Relationships among nocturnal jaw muscle activities, decreased esophageal pH, and sleep positions.

PubMed

Miyawaki, Shouichi; Tanimoto, Yuko; Araki, Yoshiko; Katayama, Akira; Imai, Mikako; Takano-Yamamoto, Teruko

2004-11-01

The purpose of this study was to examine the relationships among nocturnal jaw muscle activities, decreased esophageal pH, and sleep positions. Twelve adult volunteers, including 4 bruxism patients, participated in this study. Portable pH monitoring, electromyography of the temporal muscle, and audio-video recordings were conducted during the night in the subjects' homes. Rhythmic masticatory muscle activity (RMMA) episodes were observed most frequently, with single short-burst episodes the second most frequent. The frequencies of RMMA, single short-burst, and clenching episodes were significantly higher during decreased esophageal pH episodes than those during other times. Both the electromyography and the decreased esophageal pH episodes were most frequently observed in the supine position. These results suggest that most jaw muscle activities, ie, RMMA, single short-burst, and clenching episodes, occur in relation to gastroesophageal reflux mainly in the supine position.

Jaw-muscle fiber architecture in tufted capuchins favors generating relatively large muscle forces without compromising jaw gape.

PubMed

Taylor, Andrea B; Vinyard, Christopher J

2009-12-01

Tufted capuchins (sensu lato) are renowned for their dietary flexibility and capacity to exploit hard and tough objects. Cebus apella differs from other capuchins in displaying a suite of craniodental features that have been functionally and adaptively linked to their feeding behavior, particularly the generation and dissipation of relatively large jaw forces. We compared fiber architecture of the masseter and temporalis muscles between C. apella (n=12) and two "untufted" capuchins (C. capucinus, n=3; C. albifrons, n=5). These three species share broadly similar diets, but tufted capuchins occasionally exploit mechanically challenging tissues. We tested the hypothesis that tufted capuchins exhibit architectural properties of their jaw muscles that facilitate relatively large forces including relatively greater physiologic cross-sectional areas (PCSA), more pinnate fibers, and lower ratios of mass to tetanic tension (Mass/P(0)). Results show some evidence supporting these predictions, as C. apella has relatively greater superficial masseter and temporalis PCSAs, significantly so only for the temporalis following Bonferroni adjustment. Capuchins did not differ in pinnation angle or Mass/P(0). As an architectural trade-off between maximizing muscle force and muscle excursion/contraction velocity, we also tested the hypothesis that C. apella exhibits relatively shorter muscle fibers. Contrary to our prediction, there are no significant differences in relative fiber lengths between tufted and untufted capuchins. Therefore, we attribute the relatively greater PCSAs in tufted capuchins primarily to their larger muscle masses. These findings suggest that relatively large jaw-muscle PCSAs can be added to the suite of masticatory features that have been functionally linked to the exploitation of a more resistant diet by C. apella. By enlarging jaw-muscle mass to increase PCSA, rather than reducing fiber lengths and increasing pinnation, tufted capuchins appear to have

The relationship between jaw-opening force and the cross-sectional area of the suprahyoid muscles in healthy elderly.

PubMed

Kajisa, E; Tohara, H; Nakane, A; Wakasugi, Y; Hara, K; Yamaguchi, K; Yoshimi, K; Minakuchi, S

2018-03-01

We conducted a clinical cross-sectional study to examine the relationship between jaw-opening force and the cross-sectional area of the suprahyoid muscles and whole skeletal muscle mass. Subjects were healthy 39 males and 51 females without dysphagia and sarcopenia, aged 65 years and older. Jaw-opening force was measured three times using a jaw-opening sthenometer; the maximum of these three was taken as the measurement value. The cross-sectional area of the geniohyoid and anterior belly of the digastric muscles were evaluated using ultrasonography. The skeletal muscle mass index, gait speed and grip strength were evaluated according to the diagnostic criteria of the Asian Working Group for Sarcopenia. For each sex, a multiple regression analysis determined the factors that affect jaw-opening force. Jaw-opening force was associated with the cross-sectional area of the geniohyoid muscle in males (regression coefficient [β] = 0.441, 95% confidence interval [CI] = 14.28-56.09) and females (β = 0.28, 95% CI = 3.10-54.57). Furthermore, in females only, jaw-opening force was associated with the skeletal muscle mass index (β = 0.40, 95% CI = 3.67-17.81). In contrast, jaw-opening force was not associated with the cross-sectional area of the anterior belly of the digastric muscle in either sex. In healthy elderly males and females, jaw-opening force was positively associated with the cross-sectional area of the geniohyoid muscle. However, the jaw-opening force was positively associated with the skeletal muscle mass index only in females. © 2017 John Wiley & Sons Ltd.

Compression force on the upper jaw during neonatal intubation: mannequin study.

PubMed

Doreswamy, Srinivasa Murthy; Almannaei, Khaled; Fusch, Chris; Shivananda, Sandesh

2015-03-01

Neonatal intubation is a technically challenging procedure, and pressure-related injuries to surrounding structures have been reported. The primary objective of this study was to determine the pressure exerted on the upper jaw during tracheal intubation using a neonatal mannequin. Multidisciplinary care providers working at a neonatal intensive care unit were requested to intubate a neonatal mannequin using the standard laryngoscope and 3.0-mm (internal diameter) endotracheal tube. Compression force exerted was measured by using pressure-sensitive film taped on the upper jaw before every intubation attempt. Pressure, area under pressure and time taken to intubate were compared between the different types of health-care professionals. Thirty care providers intubated the mannequin three times each. Pressure impressions were observed on the developer film after every intubation attempt (n = 90). The mean pressure exerted during intubation across all health-care providers was 568 kPa (SD 78). The mean area placed under pressure was 142 mm(2) (SD 45), and the mean time taken for intubation was 14.7 s (SD 4.3). There was no difference in pressure exerted on the upper jaw between frequent and less frequent intubators. It was found that pressure greater than 400 kPa was inadvertently applied on the upper jaw during neonatal intubation, far exceeding the 250 kPa shown to cause tissue injury in animal models. The upper jaw is exposed to a significant compression force during intubation. Although such exposure is brief, it has the potential to cause tissue injury. Contact of the laryngoscope blade with the upper jaw occurred in all intubation attempts with the currently used design of laryngoscope. © 2014 The Authors. Journal of Paediatrics and Child Health © 2014 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

Getting a Grip on Memory: Unilateral Hand Clenching Alters Episodic Recall

DTIC Science & Technology

2013-04-24

States of America Abstract Unilateral hand clenching increases neuronal activity in the frontal lobe of the contralateral hemisphere. Such hand clenching...Simple clenching of one versus the other hand increases the neuronal activity of the frontal lobe in the opposite (contralateral) hemisphere [1], [2...hemispheres are thought to be differentially involved in many functions, including language , emotion, spatial processing, and local/global informa

A supplementary system for a brain-machine interface based on jaw artifacts for the bidimensional control of a robotic arm.

PubMed

Costa, Álvaro; Hortal, Enrique; Iáñez, Eduardo; Azorín, José M

2014-01-01

Non-invasive Brain-Machine Interfaces (BMIs) are being used more and more these days to design systems focused on helping people with motor disabilities. Spontaneous BMIs translate user's brain signals into commands to control devices. On these systems, by and large, 2 different mental tasks can be detected with enough accuracy. However, a large training time is required and the system needs to be adjusted on each session. This paper presents a supplementary system that employs BMI sensors, allowing the use of 2 systems (the BMI system and the supplementary system) with the same data acquisition device. This supplementary system is designed to control a robotic arm in two dimensions using electromyographical (EMG) signals extracted from the electroencephalographical (EEG) recordings. These signals are voluntarily produced by users clenching their jaws. EEG signals (with EMG contributions) were registered and analyzed to obtain the electrodes and the range of frequencies which provide the best classification results for 5 different clenching tasks. A training stage, based on the 2-dimensional control of a cursor, was designed and used by the volunteers to get used to this control. Afterwards, the control was extrapolated to a robotic arm in a 2-dimensional workspace. Although the training performed by volunteers requires 70 minutes, the final results suggest that in a shorter period of time (45 min), users should be able to control the robotic arm in 2 dimensions with their jaws. The designed system is compared with a similar 2-dimensional system based on spontaneous BMIs, and our system shows faster and more accurate performance. This is due to the nature of the control signals. Brain potentials are much more difficult to control than the electromyographical signals produced by jaw clenches. Additionally, the presented system also shows an improvement in the results compared with an electrooculographic system in a similar environment.

A Supplementary System for a Brain-Machine Interface Based on Jaw Artifacts for the Bidimensional Control of a Robotic Arm

PubMed Central

Costa, Álvaro; Hortal, Enrique; Iáñez, Eduardo; Azorín, José M.

2014-01-01

Non-invasive Brain-Machine Interfaces (BMIs) are being used more and more these days to design systems focused on helping people with motor disabilities. Spontaneous BMIs translate user's brain signals into commands to control devices. On these systems, by and large, 2 different mental tasks can be detected with enough accuracy. However, a large training time is required and the system needs to be adjusted on each session. This paper presents a supplementary system that employs BMI sensors, allowing the use of 2 systems (the BMI system and the supplementary system) with the same data acquisition device. This supplementary system is designed to control a robotic arm in two dimensions using electromyographical (EMG) signals extracted from the electroencephalographical (EEG) recordings. These signals are voluntarily produced by users clenching their jaws. EEG signals (with EMG contributions) were registered and analyzed to obtain the electrodes and the range of frequencies which provide the best classification results for 5 different clenching tasks. A training stage, based on the 2-dimensional control of a cursor, was designed and used by the volunteers to get used to this control. Afterwards, the control was extrapolated to a robotic arm in a 2-dimensional workspace. Although the training performed by volunteers requires 70 minutes, the final results suggest that in a shorter period of time (45 min), users should be able to control the robotic arm in 2 dimensions with their jaws. The designed system is compared with a similar 2-dimensional system based on spontaneous BMIs, and our system shows faster and more accurate performance. This is due to the nature of the control signals. Brain potentials are much more difficult to control than the electromyographical signals produced by jaw clenches. Additionally, the presented system also shows an improvement in the results compared with an electrooculographic system in a similar environment. PMID:25390372

The biological basis of treating jaw discrepancies: An interplay of mechanical forces and skeletal configuration.

PubMed

Karamesinis, Konstantinos; Basdra, Efthimia K

2018-05-01

Jaw discrepancies and malrelations affect a large proportion of the general population and their treatment is of utmost significance for individuals' health and quality of life. The aim of their therapy is the modification of aberrant jaw development mainly by targeting the growth potential of the mandibular condyle through its cartilage, and the architectural shape of alveolar bone through a suture type of structure, the periodontal ligament. This targeted treatment is achieved via external mechanical force application by using a wide variety of intraoral and extraoral appliances. Condylar cartilage and sutures exhibit a remarkable plasticity due to the mechano-responsiveness of the chondrocytes and the multipotent mesenchymal cells of the sutures. The tissues respond biologically and adapt to mechanical force application by a variety of signaling pathways and a final interplay between the proliferative activity and the differentiation status of the cells involved. These targeted therapeutic functional alterations within temporo-mandibular joint ultimately result in the enhancement or restriction of mandibular growth, while within the periodontal ligament lead to bone remodeling and change of its architectural structure. Depending on the form of the malrelation presented, the above treatment approaches, in conjunction or separately, lead to the total correction of jaw discrepancies and the achievement of facial harmony and function. Overall, the treatment of craniofacial and jaw anomalies can be seen as an interplay of mechanical forces and adaptations occurring within temporo-mandibular joint and alveolar bone. The aim of the present review is to present up-to-date knowledge on the mechano-biology behind jaw growth modification and alveolar bone remodeling. Furthermore, future molecular targeted therapeutic strategies are discussed aiming at the improvement of mechanically-driven chondrogenesis and osteogenesis. Copyright © 2018 Elsevier B.V. All rights reserved.

Experimental teeth clenching in man.

PubMed

Christensen, L V

1989-01-01

The thesis develops an electromyographic (EMG) method to quantify maximum voluntary teeth clenching (MVC), studies the onset and endurance of jaw muscle fatigue and pain from MVC, and explores the prevention of the discomforts through pharmacological and physical means. MVC, or maximum voluntary static work efforts by the elevator muscles of the mandible, was quantified by continuous (integral) functions of variations in both time and recruitment/rate coding of motor units in the masseter muscle. Fatigue was felt in the masseter muscle after about 30 seconds of MVC; differential calculus suggested that the appearance and disappearance of fatigue was associated with primarily recruitment and decruitment of masseteric motor units, respectively. About 60 seconds of MVC elicited a mild pain in the masseter and temporalis muscles; about 120 seconds of MVC induced a moderate pain and complete exhaustion of the isometrically contracting muscles. Although pain releasing maximum static work efforts are stable variables they cannot predict the pain magnitude of brief and prolonged MVC, probably because of modulations (recruitment/decruitment/rate coding) of masseteric motor units. It is suggested that the modulations begin with the onset of fatigue, are practically complete with the onset of pain, and are absent or negligible with an experience of exhaustion. A single oral dose of 1000 mg of ibuprofen did not affect the onset, endurance, and magnitude of pain from MVC. By contrast, 30 minutes of cooling (ice) of the masseter muscle effectively prevented the onset of pain; it also increased the masseteric EMG, credibly because of modulations of myoelectrical signals and, possibly, increased MVC efforts in the absence of pain.

Body posture and hand strength of patients with temporomandibular disorder.

PubMed

Shiau, Y Y; Chai, H M

1990-07-01

The aim of this study was to observe the difference between patients of craniocervical muscle pain and nonpatients in head-neck posture, masticatory muscle activity, and the force exerted by the hand. Fifty-one patients and 28 nonpatients were observed. The electric activity of the masseter muscles was recorded when the subjects were doing pinching or grasping with the jaw in positions of rest, clenched, and clenched with gauze. Measurement of right and left tilting or extension and flexion of the head and neck was made from photographs of frontal and lateral views. It was found that the pinching and grasping force was much stronger in men than in women and in nonpatients than in patients with pain. The pinching and grasping force was more powerful with the teeth clenched. Clenching with gauze did not increase, but more often decreased the strength of the hand. The activity of the masseter muscle during clenching was about 10 to 26 times that of the resting activity. The activity decreased slightly when clenching with pinching or grasping. Patients were more likely to have a stretched neck with more extension of the head. Their masseter muscle activity and hand force were significantly weaker than that of the nonpatients.

Jaw tremor as a physiological biomarker of bruxism.

PubMed

Laine, C M; Yavuz, Ş U; D'Amico, J M; Gorassini, M A; Türker, K S; Farina, D

2015-09-01

To determine if sleep bruxism is associated with abnormal physiological tremor of the jaw during a visually-guided bite force control task. Healthy participants and patients with sleep bruxism were given visual feedback of their bite force and asked to trace triangular target trajectories (duration=20s, peak force <35% maximum voluntary force). Bite force control was quantified in terms of the power spectra of force fluctuations, masseter EMG activity, and force-to-EMG coherence. Patients had greater jaw force tremor at ∼8 Hz relative to controls, along with increased masseter EMG activity and force-to-EMG coherence in the same frequency range. Patients also showed lower force-to-EMG coherence at low frequencies (<3 Hz), but greater coherence at high frequencies (20-40 Hz). Finally, patients had greater 6-10 Hz force tremor during periods of descending vs. ascending force, while controls showed no difference in tremor with respect to force dynamics. Patients with bruxism have abnormal jaw tremor when engaged in a visually-guided bite force task. Measurement of jaw tremor may aid in the detection/evaluation of bruxism. In light of previous literature, our results also suggest that bruxism is marked by abnormal or mishandled peripheral feedback from the teeth. Copyright © 2015. Published by Elsevier Ireland Ltd.

The relationships among jaw-muscle fiber architecture, jaw morphology, and feeding behavior in extant apes and modern humans.

PubMed

Taylor, Andrea B; Vinyard, Christopher J

2013-05-01

The jaw-closing muscles are responsible for generating many of the forces and movements associated with feeding. Muscle physiologic cross-sectional area (PCSA) and fiber length are two architectural parameters that heavily influence muscle function. While there have been numerous comparative studies of hominoid and hominin craniodental and mandibular morphology, little is known about hominoid jaw-muscle fiber architecture. We present novel data on masseter and temporalis internal muscle architecture for small- and large-bodied hominoids. Hominoid scaling patterns are evaluated and compared with representative New- (Cebus) and Old-World (Macaca) monkeys. Variation in hominoid jaw-muscle fiber architecture is related to both absolute size and allometry. PCSAs scale close to isometry relative to jaw length in anthropoids, but likely with positive allometry in hominoids. Thus, large-bodied apes may be capable of generating both absolutely and relatively greater muscle forces compared with smaller-bodied apes and monkeys. Compared with extant apes, modern humans exhibit a reduction in masseter PCSA relative to condyle-M1 length but retain relatively long fibers, suggesting humans may have sacrificed relative masseter muscle force during chewing without appreciably altering muscle excursion/contraction velocity. Lastly, craniometric estimates of PCSAs underestimate hominoid masseter and temporalis PCSAs by more than 50% in gorillas, and overestimate masseter PCSA by as much as 30% in humans. These findings underscore the difficulty of accurately estimating jaw-muscle fiber architecture from craniometric measures and suggest models of fossil hominin and hominoid bite forces will be improved by incorporating architectural data in estimating jaw-muscle forces. Copyright © 2013 Wiley Periodicals, Inc.

Jaw-opening force test to screen for Dysphagia: preliminary results.

PubMed

Hara, Koji; Tohara, Haruka; Wada, Satoko; Iida, Takatoshi; Ueda, Koichiro; Ansai, Toshihiro

2014-05-01

To assess the jaw-opening force test (JOFT) for dysphagia screening. Criterion standard. University dental hospital. Patients complaining of dysphagia (N=95) and with symptoms of dysphagia with chronic underlying causes (mean age ± SD, 79.3±9.61y; range, 50-94y; men: n=49; mean age ± SD, 77.03±9.81y; range, 50-94y; women: n=46; mean age ± SD, 75.42±9.73y; range, 51-93y) admitted for treatment between May 2011 and December 2012 were included. None. All patients were administered the JOFT and underwent fiberoptic endoscopic evaluation of swallowing (FEES). The mean jaw-opening strength was compared with aspiration (ASP) and pharyngeal residue observations of the FEES, which was used as the criterion standard. A receiver operating characteristic (ROC) curve analysis was performed. Forces of ≤3.2kg for men and ≤4kg for women were appropriate cutoff values for predicting ASP with a sensitivity and specificity of .57 and .79 for men and .93 and .52 for women, respectively. Based on the ROC analyses for predicting pharyngeal residue, forces of ≤5.3kg in men and ≤3.9kg in women were appropriate cutoff values, with a sensitivity and specificity of .80 and .88 for men and .83 and .81 for women, respectively. The JOFT could be a useful screening tool for predicting pharyngeal residue and could provide useful information to aid in the referral of patients for further diagnostic imaging testing. However, given its low sensitivity to ASP the JOFT should be paired with other screening tests that predict ASP. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Alterations in Masticatory Muscle Activation in People with Persistent Neck Pain Despite the Absence of Orofacial Pain or Temporomandibular Disorders.

PubMed

Testa, Marco; Geri, Tommaso; Gizzi, Leonardo; Petzke, Frank; Falla, Deborah

2015-01-01

To assess whether patients with persistent neck pain display evidence of altered masticatory muscle behavior during a jaw-clenching task, despite the absence of orofacial pain or temporomandibular disorders. Ten subjects with persistent, nonspecific neck pain and 10 age- and sex-matched healthy controls participated. Maximal voluntary contractions (MVCs) of unilateral jaw clenching followed by 5-second submaximal contractions at 10%, 30%, 50%, and 70% MVC were recorded by two flexible force transducers positioned between the first molar teeth. Task performance was quantified by mean distance and offset error from the reference target force as error indices, and standard deviation of force was used as an index of force steadiness. Electromyographic (EMG) activity was recorded bilaterally from the masseter muscle with 13 X 5 grids of electrodes and from the anterior temporalis with bipolar electrodes. Normalized EMG root mean square (RMS) was computed for each location of the grid to form a map of the EMG amplitude distribution, and the average normalized RMS was determined for the bipolar acquisition. Between-group differences were analyzed with the Kruskal Wallis analysis of variance. Task performance was similar in patients and controls. However, patients displayed greater masseter EMG activity bilaterally at higher force levels (P<.05). This study has provided novel evidence of altered motor control of the jaw in people with neck pain despite the absence of orofacial pain or temporomandibular disorders.

Craniomandibular System and Postural Balance after 3-Day Dry Immersion

PubMed Central

Treffel, Loïc; Dmitrieva, Liubov; Gauquelin-Koch, Guillemette; Custaud, Marc-Antoine; Blanc, Stéphane; Gharib, Claude; Millet, Catherine

2016-01-01

The objective of the study was to determine the influence of simulated microgravity by exposure to dry immersion on the craniomandibular system. Twelve healthy male volunteers participated in a 3-day dry immersion study. Before and immediately after exposure we measured maximal bite force using piezoresistive sensors. The mechanical properties of the jaw and cervical muscles were evaluated before, during, and after dry immersion using MyotonPRO. Because recent studies reported the effects of jaw motor activity on the postural stability of humans, stabilometric measurements of center of pressure were performed before and after dry immersion in two mandibular positions: rest position without jaw clenching, and intercuspidal position during voluntary teeth clenching. Results revealed no significant changes of maximal bite force after dry immersion. All postural parameters were significantly altered by dry immersion. There were however no significant differences in stabilometric data according to mandibular position. Moreover the masseter tonicity increased immediately after the end of dry immersion period. Dry immersion could be used as a valid model for studying the effects of microgravity on human subjects. However, 3 days appear insufficient in duration to evaluate the effects of weightlessness on maximal bite force. Our research suggests a link between postural disturbance after dry immersion and masseter tonicity. PMID:26913867

Finite element analysis of stress distribution on the mandible and condylar fracture osteosynthesis during various clenching tasks.

PubMed

Hijazi, Loai; Hejazi, Wael; Darwich, Mhd Ayham; Darwich, Khaldoun

2016-12-01

The purpose of the study was to evaluate the effect of clenching tasks on the stress and strain of condylar osteosynthesis screws and plates, as well as on the stress, strain distribution and displacement on the whole mandible and bone surrounding screws. Three-dimensional finite element models of the mandible, two straight four-hole plates and eight screws were established. Six static clenching tasks were simulated in this study: incisal clench (INC), intercuspal position (ICP), right unilateral molar clench (RMOL), left unilateral molar clench (LMOL), right group function (RGF) and left group function (LGF). Based on the simulation of the six clenching tasks, none of the inserted screws and plates were broken or bended. For the whole mandibular bone, the maximum von Mises stress and von Mises strain observed were yielded by the ICP. For the bone surrounding the inserted screws, the maximum von Mises stress and von Mises strain were yielded by the LMOL (49.2 MPa and 3795.1 μ). Clenching tasks had significant effects on the stress distribution on the condylar osteosynthesis and the bone surrounding screws. Contralateral occlusion task (LMOL) had the maximal results of von Mises stress and strain and healing problems could be occur, this result confirms the importance of soft diet after surgery.

Evolutionary Trends in the Jaw Adductor Mechanics of Ornithischian Dinosaurs.

PubMed

Nabavizadeh, Ali

2016-03-01

Jaw mechanics in ornithischian dinosaurs have been widely studied for well over a century. Most of these studies, however, use only one or few taxa within a given ornithischian clade as a model for feeding mechanics across the entire clade. In this study, mandibular mechanical advantages among 52 ornithischian genera spanning all subclades are calculated using 2D lever arm methods. These lever arm calculations estimate the effect of jaw shape and difference in adductor muscle line of action on relative bite forces along the jaw. Results show major instances of overlap between taxa in tooth positions at which there was highest mechanical advantage. A relatively low bite force is seen across the tooth row among thyreophorans (e.g., stegosaurs and ankylosaurs), with variation among taxa. A convergent transition occurs from a more evenly distributed bite force along the jaw in basal ornithopods and basal marginocephalians to a strong distal bite force in hadrosaurids and ceratopsids, respectively. Accordingly, adductor muscle vector angles show repeated trends from a mid-range caudodorsal orientation in basal ornithischians to a decrease in vector angles indicating more caudally oriented jaw movements in derived taxa (e.g., derived thyreophorans, basal ornithopods, lambeosaurines, pachycephalosaurs, and derived ceratopsids). Analyses of hypothetical jaw morphologies were also performed, indicating that both the coronoid process and lowered jaw joint increase moment arm length therefore increasing mechanical advantage of the jaw apparatus. Adaptive trends in craniomandibular anatomy show that ornithischians evolved more complex feeding apparatuses within different clades as well as morphological convergences between clades. © 2016 Wiley Periodicals, Inc.

Independently evolved upper jaw protrusion mechanisms show convergent hydrodynamic function in teleost fishes.

PubMed

Staab, Katie Lynn; Holzman, Roi; Hernandez, L Patricia; Wainwright, Peter C

2012-05-01

A protrusible upper jaw has independently evolved multiple times within teleosts and has been implicated in the success of two groups in particular: Acanthomorpha and Cypriniformes. We use digital particle image velocimetry (DPIV) to compare suction feeding flow dynamics in a representative of each of these clades: goldfish and bluegill. Using DPIV, we contrast the spatial pattern of flow, the temporal relationship between flow and head kinematics, and the contribution of jaw protrusion to the forces exerted on prey. As expected, the spatial patterns of flow were similar in the two species. However, goldfish were slower to reach maximal kinematic excursions, and were more flexible in the relative timing of jaw protrusion, other jaw movements and suction flows. Goldfish were also able to sustain flow speeds for a prolonged period of time as compared with bluegill, in part because goldfish generate lower peak flow speeds. In both species, jaw protrusion increased the force exerted on the prey. However, slower jaw protrusion in goldfish resulted in less augmentation of suction forces. This difference in force exerted on prey corresponds with differences in trophic niches and feeding behavior of the two species. The bluegill uses powerful suction to capture insect larvae whereas the goldfish uses winnowing to sort through detritus and sediment. The kinethmoid of goldfish may permit jaw protrusion that is independent of lower jaw movement, which could explain the ability of goldfish to decouple suction flows (due to buccal expansion) from upper jaw protrusion. Nevertheless, our results show that jaw protrusion allows both species to augment the force exerted on prey, suggesting that this is a fundamental benefit of jaw protrusion to suction feeders.

Improving Examination Performance through the Clenched Fist Technique.

ERIC Educational Resources Information Center

Stanton, Harry E.

1988-01-01

The literature on the use of hypnosis in an educational setting is briefly reviewed, and a hypnotic approach involving the use of the clenched fist as a conditioned trigger to improve examination performance is described. A study of 60 high school students indicates that the approach can improve test outcomes. (TJH)

The measurement and facilitation of cooperative task performance. [reactions of humans to stress exposure

NASA Technical Reports Server (NTRS)

Hutchinson, R. R.

1975-01-01

Experiments were conducted to determine under what conditions jaw clenching will occur in humans as a response to stress exposure. The method for measuring reactions to stress involves a series of electrical recordings of the masseter and temporalis muscles. A high fixed-ratio response requirement in the first series of experiments shows that jaw clenching in humans occurs in situations analogous to those which produce biting in infrahuman subjects. In the second series, reduction in the amounts of money recieved by subjects is shown to cause increases in the jaw clench response and other negative effect motor behaviors. The third series demonstrates that perception of more favorable conditions existing for another person can increase anger and hostility in the subject.

Jaw-Dropping: Functional Variation in the Digastric Muscle in Bats.

PubMed

Curtis, Abigail A; Santana, Sharlene E

2018-02-01

Diet and feeding behavior in mammals is strongly linked to the morphology of their feeding apparatus. Cranio-muscular morphology determines how wide, forcefully, and quickly the jaw can be opened or closed, which limits the size and material properties of the foods that a mammal can eat. Most studies of feeding performance in mammals have focused on skull form and jaw muscles involved in generating bite force, but few explore how jaw abduction is related to feeding performance. In this study, we explored how the morphology of the digastric muscle, the primary jaw abducting muscle in mammals, and its jaw lever mechanics are related to diet in morphologically diverse noctilionoid bats. Results showed that insectivorous bats have strong digastric muscles associated with proportionally long jaws, which suggests these species can open their jaws quickly and powerfully during prey capture and chewing. Short snouted frugivorous bats exhibit traits that would enable them to open their jaws proportionally wider to accommodate the large fruits that they commonly feed on. Our results support the hypothesis that digastric muscle and jaw morphology are correlated with diet in bats, and that our results may also apply to other groups of mammals. Anat Rec, 301:279-290, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Effect of occlusal appliances and clenching on the internally deranged TMJ space.

PubMed

Kuboki, T; Takenami, Y; Orsini, M G; Maekawa, K; Yamashita, A; Azuma, Y; Clark, G T

1999-01-01

Stabilization appliances and mandibular anterior repositioning appliances have been used to treat patients with internal derangement of the temporomandibular joint (TMJ) based on the assumption that these appliances work by decompressing the TMJ. The purpose of this study was to indirectly test this assumption. Bilateral TMJ tomograms of 7 subjects with unilateral anterior disc displacement without reduction (ADDwor) were taken during comfortable closure and during maximum clenching in maximum intercuspation; tomograms were also taken with the 2 types of occlusal appliances in use. Outlines of the condyle and the temporal fossa were automatically determined by an edge-detection protocol, and the minimum joint space dimension of the joints with and without ADDwor was automatically measured for each experimental condition as the outcome variable. Upon comfortable closure and maximum clenching, the minimum joint space dimensions of the ipsilateral and contralateral joints with the use of stabilization appliances and mandibular anterior repositioning appliances were not significantly different from those seen in maximum intercuspation. These findings do not indicate that these appliances induce an increase in joint space during closing and clenching in joints with ADDwor.

Role of stag beetle jaw bending and torsion in grip on rivals.

PubMed

Goyens, Jana; Dirckx, Joris; Piessen, Maxim; Aerts, Peter

2016-01-01

In aggressive battles, the extremely large male stag beetle jaws have to withstand strongly elevated bite forces. We found several adaptations of the male Cyclommatus metallifer jaw morphology for enhanced robustness that conspecific females lack. As a result, males improve their grip on opponents and they maintain their safety factor (5.2-7.2) at the same level as that of females (6.8), despite their strongly elevated bite muscle force (3.9 times stronger). Males have a higher second moment of area and torsion constant than females, owing to an enhanced cross-sectional area and shape. These parameters also increase faster with increasing bending moment towards the jaw base in males than in females. Male jaws are more bending resistant against the bite reaction force than against perpendicular forces (which remain lower in battles). Because of the triangular cross section of the male jaw base, it twists more easily than it bends. This torsional flexibility creates a safety system against overload that, at the same time, secures a firm grip on rivals. We found no structural mechanical function of the large teeth halfway along the male jaws. Therefore, it appears that the main purpose of these teeth is a further improvement of grip on rivals. © 2016 The Author(s).

Role of stag beetle jaw bending and torsion in grip on rivals

PubMed Central

Goyens, Jana; Dirckx, Joris; Piessen, Maxim; Aerts, Peter

2016-01-01

In aggressive battles, the extremely large male stag beetle jaws have to withstand strongly elevated bite forces. We found several adaptations of the male Cyclommatus metallifer jaw morphology for enhanced robustness that conspecific females lack. As a result, males improve their grip on opponents and they maintain their safety factor (5.2–7.2) at the same level as that of females (6.8), despite their strongly elevated bite muscle force (3.9 times stronger). Males have a higher second moment of area and torsion constant than females, owing to an enhanced cross-sectional area and shape. These parameters also increase faster with increasing bending moment towards the jaw base in males than in females. Male jaws are more bending resistant against the bite reaction force than against perpendicular forces (which remain lower in battles). Because of the triangular cross section of the male jaw base, it twists more easily than it bends. This torsional flexibility creates a safety system against overload that, at the same time, secures a firm grip on rivals. We found no structural mechanical function of the large teeth halfway along the male jaws. Therefore, it appears that the main purpose of these teeth is a further improvement of grip on rivals. PMID:26763329

Biomechanical calculation of human TM joint loading with jaw opening.

PubMed

Kuboki, T; Takenami, Y; Maekawa, K; Shinoda, M; Yamashita, A; Clark, G T

2000-11-01

A three-dimensional, static mathematical calculation of the stomatognathic system was done to predict total temporomandibular joint (TMJ) loading at different levels of jaw opening. The model assumed that muscle forces acting on the mandible could be simulated by a combination of contractile components (CCs) and elastic components (ECs) and that static equilibrium existed within the body of the mandible. The model also imposed the constraint that any generated joint reaction force would act on the centre of the condyle. The results of the model demonstrated that under all conditions of opening and for all values of the elastic modulus selected, the forces between the TMJ condyle and the articular eminence were compressive in nature. The compressive force magnitude increased from 2.7 to 27.6 N incrementally as the jaw opened from 10 to 40 mm. Overall data in this study indicated that the TMJ tissues undergo low levels of compression at open positions up to 40 mm. Finally, the condition of trismus (increased jaw closing activation with opening) was simulated, the joint reaction force at 20 mm opening increased from 7.7 to 64.9 N with only a 20% activation of the closers.

Jaw elevator silent periods in complete denture wearers and dentate individuals.

PubMed

Celebic, A; Valentic-Peruzovic, M; Alajbeg, I Z; Mehulic, K; Knezovic-Zlataric, D

2008-12-01

Functional meaning and underlying mechanisms of jaw elevator silent period (SP) have still not been completely understood. Since complete denture wearers (CDWs) have no periodontal receptors in their jaws, the aim was to examine SPs in CDWs and to compare it with dentate individuals (DIs). Thirty six DIs (skeletal/occlusal Class I) and 24 eugnath CDWs participated. EMG signals were registered using the EMGA-1 apparatus from the left and the right side anterior temporalis (ATM) and masseter muscles (MM). Ten registrations of an open-close-clench (OCC) cycle were obtained for each individual. DIs had the average latency between 12.5 and 12.9 ms and always one single short inhibitory pause (IP) with complete inhibition of motoneurons (20.1-21.1 ms). On the other hand, in CDWs various types of SPs emerged: single or single prolonged SPs, double SPs, SPs with three IPs, periods of depressed muscle activity following the first, or the second IP, SPs with relative inhibition of motoneurons or even in several registrations the SP was missing. Unless more than one IP emerged, complete duration of inhibitory pauses (CDIP) was measured. CDIP varied from 37.17 to 42.49 ms. Average latencies were from 16.22 to 16.76 ms. Based on the results of this study it is obvious that both, the duration and the latencies were significantly longer in CDWs than in DIs (p<0.05), which can be explained by different mechanisms responsible for the muscle reflex behaviour.

Co-contraction behaviour of masticatory and neck muscles during tooth grinding.

PubMed

Giannakopoulos, N N; Schindler, H J; Hellmann, D

2018-07-01

The objective of this study was to analyse the co-contraction behaviour of jaw and neck muscles during force-controlled experimental grinding in the supine position. Twelve symptom-free subjects were enrolled in the experimental study. Electromyographic (EMG) activity of semispinalis capitis, splenius capitis and levator scapulae muscles was recorded bilaterally with intramuscular fine-wire electrodes, whereas that of sternocleidomastoideus, infrahyoidal, suprahyoidal, masseter and anterior temporalis muscles were registered with surface electrodes. EMG and force measurements were performed during tasks simulating tooth grinding on custom-made intraoral metal splints. The mean EMG activity normalised by maximum voluntary contraction (% MVC) of each of the neck muscles studied during grinding was analysed and compared with previous data from jaw clenching at identical force (100 N) and (supine) position. The occurrence of low-level, long-lasting tonic activation (LLTA) of motor units was also documented. The mean three-dimensional force vector of the grinding forces was 106 ± 74 N. In the frontal plane, the incline to the midsagittal plane ranged between 10° and 15°. In the midsagittal plane, the incline to the frontal plane was negligibly small. Posterior neck muscle activity during grinding ranged between 4.5% and 12% MVC and during clenching with 100 N between 1.8% and 9.9% MVC. Masticatory muscle activity during grinding ranged between 17% and 21% MVC for contralateral masseter and ipsilateral temporalis and between 4% and 6.5% for ipsilateral masseter and contralateral temporalis. LLTA had an average duration of 195 ± 10 seconds. The findings from this study do not support pathophysiological muscle chain theories postulating simple biomechanical coupling of neck and jaw muscles. Co-contractions of neck and masticatory muscles may instead occur as a result of complex neurophysiological interactions. © 2018 John Wiley & Sons Ltd.

Double lead spiral platen parallel jaw end effector

NASA Technical Reports Server (NTRS)

Beals, David C.

1989-01-01

The double lead spiral platen parallel jaw end effector is an extremely powerful, compact, and highly controllable end effector that represents a significant improvement in gripping force and efficiency over the LaRC Puma (LP) end effector. The spiral end effector is very simple in its design and has relatively few parts. The jaw openings are highly predictable and linear, making it an ideal candidate for remote control. The finger speed is within acceptable working limits and can be modified to meet the user needs; for instance, greater finger speed could be obtained by increasing the pitch of the spiral. The force relaxation is comparable to the other tested units. Optimization of the end effector design would involve a compromise of force and speed for a given application.

A Vibrating Jaw Crusher with Auteresonant Electric Motor Drive of Swinging Movement

NASA Astrophysics Data System (ADS)

Zagrivniy, E. A.; Poddubniy, D. A.

2018-01-01

The article relates to a vibrating jaw crusher with pendulum vibrating exciter auteresonant electric motor drive and with elastic element rational force distribution, with limited peak-to-peak swing. Its design and its math model are presented. Also disclosed is the operating principle of a vibrating jaw crusher and the control algorithm for controlling the crushing jaw for maintaining the operating mode at resonant frequency.

Activation time analysis and electromyographic fatigue in patients with temporomandibular disorders during clenching.

PubMed

Pitta, Natássia Condilo; Nitsch, Gabriel Silva; Machado, Mariana Barcellos; de Oliveira, Anamaria Siriani

2015-08-01

The use of surface electromyography (SEMG) is controversial in the diagnosis and subsequent treatment of temporomandibular disorders (TMD), although there is some evidence that the pattern of the masticatory muscles in TMD patients differs from controls. The aim of this study was to compare relative time of mandibular elevator muscle activation at different levels of activity and median frequency (MF) during sustained clenching. Twenty-two women, aged between 18 and 48years, volunteered to participate in the study. The TMD group had 14 participants diagnosed as group Ia muscle disorders (RDC/TMD). The control group had eight healthy individuals. SEMG records were obtained from masseter and temporal muscles during 10s of sustained clenching. Normalized SEMG amplitudes were classified as minimal, moderate and maximal and time of activation in each level of activity was calculated and compared using two-way ANOVA (groups versus time). A slope of the linear regression line that fits MF values over time was calculated as a fatigue index for elevator muscles. Only the temporal muscles of the TMD group showed longer activation time at moderate and minimal activity levels compared to controls. Fatigue indexes were greater for the TMD group compared to controls. Results showed motor control strategies during sustained clenching that differentiate controls from TMD patients. Copyright © 2015 Elsevier Ltd. All rights reserved.

Disturbed jaw behavior in whiplash-associated disorders during rhythmic jaw movements.

PubMed

Häggman-Henrikson, B; Zafar, H; Eriksson, P-O

2002-11-01

As shown previously, "functional jaw movements" are the result of coordinated activation of jaw as well as neck muscles, leading to simultaneous movements in the temporomandibular, atlanto-occipital, and cervical spine joints. In this study, the effect of neck trauma on natural jaw function was evaluated in 12 individuals suffering from whiplash-associated disorders (WAD). Spatiotemporal characteristics of mandibular and concomitant head movements were evaluated for three different modes of rhythmic jaw activities: self-paced continuous maximal jaw-opening/-closing movements, paced continuous maximal jaw-opening/-closing movements at 50 cycles/minute, and unilateral chewing. Compared with healthy subjects, the WAD group showed smaller magnitude and altered coordination pattern (a change in temporal relations) of mandibular and head movements. In conclusion, these results show that neck trauma can derange integrated jaw and neck behavior, and underline the functional coupling between the jaw and head-neck motor systems.

The relationship between facial skeleton morphology and bite force in people with a normal relation of the bases of jaws and skull.

PubMed

Sidorowicz, Ł; Szymańska, J

2015-01-01

Better knowledge on the relationship between craniofacial structure and bite force may serve as a reference point for prophylactic and therapeutic activities targeted at developmental age patients. The aim of the study was to assess the correlation between facial skeletal morphology and bite force. The study included 54 subjects aged 7-16 years with a normal relation of the bases of jaws and skull, according to Segner's and Hasund's analysis standards (ML-NL and ML-NSL angles values were 20.0 ± 7.0° and 28.0 ± 5.0°, respectively). The study group included patients who volunteered to diagnosis and possible orthodontic treatment. Bite force was tested with a digital dynamometer calibrated in Newtons. The measurement was performed at the level of the first permanent molars. Cephalometric analysis was based on lateral cephalometric radiographs. The vertical relations were assessed using the following measurements: ML-NSL, ML-NL, NL-NSL, N-Me, Sp-Me, SpMe:NMe, ms-NL, SGo:NMe. Bite force does not depend on the following factors: lower anterior face height (Sp-Me), lower anterior face height to total anterior face height ratio (SpMe:NMe), posterior to anterior face height ratio (SG0:NMe), and the value of ML-NL, ML-NSL and NL-NSL angles. The posterior height of the maxilla alveolar process (ms-NL) exerts the greatest influence on bite force in people with a normal relation of the bases of jaws and skull: with an increase in ms-NL value bite force is reduced.

FGF and TGFβ signaling link form and function during jaw development and evolution.

PubMed

Woronowicz, Katherine C; Gline, Stephanie E; Herfat, Safa T; Fields, Aaron J; Schneider, Richard A

2018-05-16

How does form arise during development and change during evolution? How does form relate to function, and what enables embryonic structures to presage their later use in adults? To address these questions, we leverage the distinct functional morphology of the jaw in duck, chick, and quail. In connection with their specialized mode of feeding, duck develop a secondary cartilage at the tendon insertion of their jaw adductor muscle on the mandible. An equivalent cartilage is absent in chick and quail. We hypothesize that species-specific jaw architecture and mechanical forces promote secondary cartilage in duck through the differential regulation of FGF and TGFβ signaling. First, we perform transplants between chick and duck embryos and demonstrate that the ability of neural crest mesenchyme (NCM) to direct the species-specific insertion of muscle and the formation of secondary cartilage depends upon the amount and spatial distribution of NCM-derived connective tissues. Second, we quantify motility and build finite element models of the jaw complex in duck and quail, which reveals a link between species-specific jaw architecture and the predicted mechanical force environment. Third, we investigate the extent to which mechanical load mediates FGF and TGFβ signaling in the duck jaw adductor insertion, and discover that both pathways are mechano-responsive and required for secondary cartilage formation. Additionally, we find that FGF and TGFβ signaling can also induce secondary cartilage in the absence of mechanical force or in the adductor insertion of quail embryos. Thus, our results provide novel insights on molecular, cellular, and biomechanical mechanisms that couple musculoskeletal form and function during development and evolution. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Choice of biomaterials—Do soft occlusal splints influence jaw-muscle activity during sleep? A preliminary report

NASA Astrophysics Data System (ADS)

Arima, Taro; Takeuchi, Tamiyo; Tomonaga, Akio; Yachida, Wataru; Ohata, Noboru; Svensson, Peter

2012-12-01

AimThe choice of biomaterials for occlusal splints may significantly influence biological outcome. In dentistry, hard acrylic occlusal splints (OS) have been shown to have a temporary and inhibitory effect on jaw-muscle activity, such as tooth clenching and grinding during sleep, i.e., sleep bruxism (SB). Traditionally, this inhibitory effect has been explained by changes in the intraoral condition rather than the specific effects of changes in occlusion. The aim of this preliminary study was to investigate the effect of another type of occlusal surface, such as a soft-material OS in addition to a hard-type OS in terms of changes in jaw-muscle activity during sleep. Materials and methodsSeven healthy subjects (mean ± SD, six men and one woman: 28.9 ± 2.7 year old), participated in this study. A soft-material OS (ethylene vinyl acetate copolymer) was fabricated for each subject and the subjects used the OS for five continuous nights. The EMG activity during sleep was compared to baseline (no OS). Furthermore, the EMG activity during the use of a hard-type OS (Michigan-type OS, acrylic resin), and hard-type OS combined with contingent electrical stimulation (CES) was compared to baseline values. Each session was separated by at least two weeks (washout). Jaw-muscle activity during sleep was recorded with single-channel ambulatory devices (GrindCare, MedoTech, Herlev, Denmark) in all sessions for five nights. ResultsJaw-muscle activity during sleep was 46.6 ± 29.8 EMG events/hour at baseline and significantly decreased during the hard-type OS (17.4 ± 10.5, P = 0.007) and the hard-type OS + CES (10.8 ± 7.1, P = 0.002), but not soft-material OS (36.3 ± 24.5, P = 0.055). Interestingly, the soft-material OS (coefficient of variance = 98.6 ± 35.3%) was associated with greater night-to-night variations than baseline (39.0 ± 11.8%) and the hard-type OS + CES (53.3 ± 13.7%, P < 0.013). ConclusionThe present pilot study in small sample showed that a soft

Strength improvements through occlusal splints? The effects of different lower jaw positions on maximal isometric force production and performance in different jumping types

PubMed Central

Maurer, Christian; Heller, Sebastian; Sure, Jil-Julia; Fuchs, Daniel; Mickel, Christoph; Wanke, Eileen M.; Groneberg, David A.

2018-01-01

Objective The influence of the jaw position on postural control, body posture, walking and running pattern has been reported in the literature. All these movements have in common that a relatively small, but well controlled muscle activation is required. The induced effects on motor output through changed jaw positions have been small. Therefore, it has been questioned if it could still be observed in maximal muscle activation. Method Twenty-three healthy, mid age recreational runners (mean age = 34.0 ± 10.3 years) participated in this study. Three different jump tests (squat jump, counter movement jump, and drop jumps from four different heights) and three maximal strength tests (trunk flexion and extension, leg press of the right and left leg) were conducted. Four different dental occlusion conditions and an additional familiarization condition were tested. Subjects performed the tests on different days for which the four occlusion conditions were randomly changed. Results No familiarization effect was found. Occlusion conditions with a relaxation position and with a myocentric condylar position showed significantly higher values for several tests compared to the neutral condition and the maximal occlusion position. Significance was found in the squat jump, countermovement jump, the drop jump from 32cm and 40cm, trunk extension, leg press force and rate of force development. The effect due to the splint conditions is an improvement between 3% and 12% (min and max). No influence of the jaw position on symmetry or balance between extension and flexion muscle was found. Conclusion An influence of occlusion splints on rate of force development (RFD) and maximal strength tests could be confirmed. A small, but consistent increase in the performance parameters could be measured. The influence of the occlusion condition is most likely small compared to other influences as for example training status, age, gender and circadian rhythm. PMID:29474465

Developmental finite element analysis of cichlid pharyngeal jaws: Quantifying the generation of a key innovation.

PubMed

Peterson, Tim; Müller, Gerd B

2018-01-01

Advances in imaging and modeling facilitate the calculation of biomechanical forces in biological specimens. These factors play a significant role during ontogenetic development of cichlid pharyngeal jaws, a key innovation responsible for one of the most prolific species diversifications in recent times. MicroCT imaging of radiopaque-stained vertebrate embryos were used to accurately capture the spatial relationships of the pharyngeal jaw apparatus in two cichlid species (Haplochromis elegans and Amatitlania nigrofasciata) for the purpose of creating a time series of developmental stages using finite element models, which can be used to assess the effects of biomechanical forces present in a system at multiple points of its ontogeny. Changes in muscle vector orientations, bite forces, force on the neurocranium where cartilage originates, and stress on upper pharyngeal jaws are analyzed in a comparative context. In addition, microCT scanning revealed the presence of previously unreported cement glands in A. nigrofasciata. The data obtained provide an underrepresented dimension of information on physical forces present in developmental processes and assist in interpreting the role of developmental dynamics in evolution.

Developmental finite element analysis of cichlid pharyngeal jaws: Quantifying the generation of a key innovation

PubMed Central

Müller, Gerd B.

2018-01-01

Advances in imaging and modeling facilitate the calculation of biomechanical forces in biological specimens. These factors play a significant role during ontogenetic development of cichlid pharyngeal jaws, a key innovation responsible for one of the most prolific species diversifications in recent times. MicroCT imaging of radiopaque-stained vertebrate embryos were used to accurately capture the spatial relationships of the pharyngeal jaw apparatus in two cichlid species (Haplochromis elegans and Amatitlania nigrofasciata) for the purpose of creating a time series of developmental stages using finite element models, which can be used to assess the effects of biomechanical forces present in a system at multiple points of its ontogeny. Changes in muscle vector orientations, bite forces, force on the neurocranium where cartilage originates, and stress on upper pharyngeal jaws are analyzed in a comparative context. In addition, microCT scanning revealed the presence of previously unreported cement glands in A. nigrofasciata. The data obtained provide an underrepresented dimension of information on physical forces present in developmental processes and assist in interpreting the role of developmental dynamics in evolution. PMID:29320528

The Effect of Varying Jaw-elevator Muscle Forces on a Finite Element Model of a Human Cranium.

PubMed

Toro-Ibacache, Viviana; O'Higgins, Paul

2016-07-01

Finite element analyses simulating masticatory system loading are increasingly undertaken in primates, hominin fossils and modern humans. Simplifications of models and loadcases are often required given the limits of data and technology. One such area of uncertainty concerns the forces applied to cranial models and their sensitivity to variations in these forces. We assessed the effect of varying force magnitudes among jaw-elevator muscles applied to a finite element model of a human cranium. The model was loaded to simulate incisor and molar bites using different combinations of muscle forces. Symmetric, asymmetric, homogeneous, and heterogeneous muscle activations were simulated by scaling maximal forces. The effects were compared with respect to strain distribution (i.e., modes of deformation) and magnitudes; bite forces and temporomandibular joint (TMJ) reaction forces. Predicted modes of deformation, strain magnitudes and bite forces were directly proportional to total applied muscle force and relatively insensitive to the degree of heterogeneity of muscle activation. However, TMJ reaction forces and mandibular fossa strains decrease and increase on the balancing and working sides according to the degree of asymmetry of loading. These results indicate that when modes, rather than magnitudes, of facial deformation are of interest, errors in applied muscle forces have limited effects. However the degree of asymmetric loading does impact on TMJ reaction forces and mandibular fossa strains. These findings are of particular interest in relation to studies of skeletal and fossil material, where muscle data are not available and estimation of muscle forces from skeletal proxies is prone to error. Anat Rec, 299:828-839, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Jaw and Order

ERIC Educational Resources Information Center

Mooshammer, Christine; Hoole, Philip; Geumann, Anja

2007-01-01

It is well-accepted that the jaw plays an active role in influencing vowel height. The general aim of the current study is to further investigate the extent to which the jaw is active in producing consonantal distinctions, with specific focus on coronal consonants. Therefore, tongue tip and jaw positions are compared for the German coronal…

A 3D visualization and simulation of the individual human jaw.

PubMed

Muftić, Osman; Keros, Jadranka; Baksa, Sarajko; Carek, Vlado; Matković, Ivo

2003-01-01

A new biomechanical three-dimensional (3D) model for the human mandible based on computer-generated virtual model is proposed. Using maps obtained from the special kinds of photos of the face of the real subject, it is possible to attribute personality to the virtual character, while computer animation offers movements and characteristics within the confines of space and time of the virtual world. A simple two-dimensional model of the jaw cannot explain the biomechanics, where the muscular forces through occlusion and condylar surfaces are in the state of 3D equilibrium. In the model all forces are resolved into components according to a selected coordinate system. The muscular forces act on the jaw, along with the necessary force level for chewing as some kind of mandible balance, preventing dislocation and loading of nonarticular tissues. In the work is used new approach to computer-generated animation of virtual 3D characters (called "Body SABA"), using in one object package of minimal costs and easy for operation.

Effects of teeth clenching on the soleus H reflex during lower limb muscle fatigue.

PubMed

Mitsuyama, Akihiro; Takahashi, Toshiyuki; Ueno, Toshiaki

2017-04-01

We assessed whether the soleus H reflex was depressed or facilitated in association with voluntary teeth clenching during muscle fatigue. A total of 13 and 9 healthy adult subjects were instructed to perform right-side tiptoe standing for 5 (TS1) and 10min (TS2) to induce the soleus muscle fatigue. Electromyograms (EMGs) were recorded from the bilateral masseter as well as the right-side soleus muscles. H reflex was evoked using a surface electrode. The isometric muscle strength during plantar flexion was measured. We tested two dental occlusal conditions (1) with maximal voluntary teeth clenching (MVTC) and (2) at mandibular rest position (RP). H reflex was evoked before and after TS1 and TS2. The isometric muscle strength during plantar flexion was measured before and after TS1 and TS2. Mean amplitudes of H reflex with MVTC before and after TS1 were significantly larger than that with RP before and after TS1. The mean peak torque (PT) during isometric plantar flexion was observed significant differences in all subjects. The mean amplitude of H reflex with MVTC before TS2 was significantly larger than that with RP before TS2. No significant difference between RP after TS2 and MVTC after TS2. The mean PT with MVTC before TS2 was significantly larger than that with RP before TS2. There was no significant difference between RP and MVTC after TS2. The present study demonstrated that teeth clenching could facilitate H reflex regardless of the degree of muscle fatigue. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Masseter muscular weakness affects temporomandibular synovitis induced by jaw opening in growing rats.

PubMed

Ozaki, Miho; Kaneko, Sawa; Soma, Kunimichi

2008-09-01

To evaluate the influence of impaired masseter function during growth on the development of temporomandibular synovitis. Sixteen 3-week-old male Wistar rats were classified into four groups. The first group served as control; and in the second group, jaw opening was forced for 3 hours when the rats were 9 weeks old. In the third and fourth groups, the masseter muscles were bilaterally resected at 3 weeks of age, and the rats in the fourth group were additionally forced to open their jaw at 9 weeks of age. All rats were sacrificed at 9 weeks. Temporomandibular joint (TMJ) tissue samples were processed for histology, and evaluated for cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expressions by immunohistochemistry to examine the inflammatory changes in the synovial membrane. The control group showed noninflammatory changes. In the jaw-opening group, vascular dilation and weak COX-2 immunoreactivity were induced by jaw opening in the synovium. In the masseter-resection group, the masseter-resected rats exhibited moderate synovial changes while in the resection with opening group, the masseter-resected rats revealed more significant inflammatory changes including synovial hyperplasia, dilated vasculature, fibrin deposits, and intense immunoreactivity for COX-2 and iNOS, all caused by jaw opening. These results suggest that masseter activity in the growth period is an important factor in the induction of temporomandibular synovitis.

Frequency of awake bruxism behaviours in the natural environment. A 7-day, multiple-point observation of real-time report in healthy young adults.

PubMed

Bracci, A; Djukic, G; Favero, L; Salmaso, L; Guarda-Nardini, L; Manfredini, D

2018-06-01

The aim of this study was to assess awake bruxism (AB) behaviours in a sample of healthy young adults using a smartphone-based application for a real-time report (ie, ecological momentary assessment [EMA], also called experience sampling method [ESM]). Forty-six dental students used a smartphone application that sent 15 alerts at random intervals during the day for 1 week to collect AB self-reports. They had to answer on time by tapping on the display icon that refers to their current condition of jaw muscles: relaxed; teeth contact; teeth clenching; teeth grinding; jaw clenching without teeth contact (ie, bracing). The average frequency of relaxed jaw muscles, as a percentage of answers over the 7 days, was 71.7%. Teeth contact (14.5%) and jaw clenching (10.0%) were the most frequent AB behaviours. No significant gender differences were detected. Interindividual differences were quite relevant, but the overall frequency was in general only moderately variable from day-to-day. Coefficient of variation (CV) was low for the condition "relaxed jaw muscles" (0.44). At the individual level, teeth contact was the most prevalent behaviour, with a 39.1%-52.2% proportion of subjects reporting it at least once a day. During a 7-day observation period, the frequency of real-time report of AB behaviours in a sample of healthy young adults was 28.3%. The low daily variability in the average frequency value for the relaxed jaw muscles condition suggests that EMA may be a reliable strategy to get deeper into the epidemiology of oral behaviours. This investigation introduced EMA principles to the study of AB and provided data on the frequency of AB behaviours in young adults that could be compared to populations with risk/associated factors and possible clinical consequences. © 2018 John Wiley & Sons Ltd.

Multi-step EMG Classification Algorithm for Human-Computer Interaction

NASA Astrophysics Data System (ADS)

Ren, Peng; Barreto, Armando; Adjouadi, Malek

A three-electrode human-computer interaction system, based on digital processing of the Electromyogram (EMG) signal, is presented. This system can effectively help disabled individuals paralyzed from the neck down to interact with computers or communicate with people through computers using point-and-click graphic interfaces. The three electrodes are placed on the right frontalis, the left temporalis and the right temporalis muscles in the head, respectively. The signal processing algorithm used translates the EMG signals during five kinds of facial movements (left jaw clenching, right jaw clenching, eyebrows up, eyebrows down, simultaneous left & right jaw clenching) into five corresponding types of cursor movements (left, right, up, down and left-click), to provide basic mouse control. The classification strategy is based on three principles: the EMG energy of one channel is typically larger than the others during one specific muscle contraction; the spectral characteristics of the EMG signals produced by the frontalis and temporalis muscles during different movements are different; the EMG signals from adjacent channels typically have correlated energy profiles. The algorithm is evaluated on 20 pre-recorded EMG signal sets, using Matlab simulations. The results show that this method provides improvements and is more robust than other previous approaches.

Functional Morphology of Eunicidan (Polychaeta) Jaws

NASA Astrophysics Data System (ADS)

Clemo, W. C.; Dorgan, K. M.

2016-02-01

Polychaetes exhibit diverse feeding strategies and diets, with some species possessing hardened teeth or jaws of varying complexity. Species in the order Eunicida have complex, rigidly articulated jaws consisting of multiple pairs of maxillae and a pair of mandibles. While all Eunicida possess this general jaw structure, a number of characteristics of the jaw parts vary considerably among families. These differences, described for fossilized and extant species' jaws, were used to infer evolutionary relationships, but current phylogeny shows that jaw structures that are similar among several families are convergent. Little has been done, however, to relate jaw functional morphology and feeding behavior to diet. To explore these relationships, we compared the jaw kinematics of two taxa with similar but evolutionarily convergent jaw structures: Diopatra (Onuphidae) and Lumbrineris (Lumbrineridae). Diopatra species are tube-dwelling and predominantly herbivorous, whereas Lumbrineris species are burrowing carnivores. Jaw kinematics were observed and analyzed by filming individuals biting or feeding and tracking tooth movements in videos. Differences in jaw structure and kinematics between Diopatra and Lumbrineris can be interpreted to be consistent with their differences in diet. Relating jaw morphology to diet would provide insight into early annelid communities by linking fossil teeth (scolecodonts) to the ecological roles of extant species with similar morphologies.

Kinematics and Mechanics analysis of trap-jaw ant Odontomachus monticola

NASA Astrophysics Data System (ADS)

Hao, Wenteng; Yao, Guang; Zhang, Xiangyu; Zhang, Deyuan

2018-03-01

Trap-jaw ants of the genus Odontomachus exhibit spectacularly rapid predatory and fugitive strikes. In order to reveal the extraordinary impact resistance of the apical teeth material, we analyzed the kinematics and mechanics of the closing mandibles. Odontomachus monticola is an Odontomachus species and extensive in China. We video-recorded jaw-strikes to measure the closing velocity and acceleration. The experimental results showed that O. monticola’s mandibles closed at a highest velocity of 35.42 m/s and a highest acceleration of 750,000 m/s2 within an average duration of 0.16 ms. In addition, in order to measure the strike force, we developed an extraordinary measuring method with poly (vinylidene fluoride) (PVDF) piezoelectric film. First, the dynamic calibration of the PVDF piezoelectric film was conducted, then the calibrated piezoelectric film was struck by O. monticola. Finally, the mandible strike force was calculated according to the calibration result and the output signal. The measurements results demonstrated that the strike force ranges from 102.2 N to 235.2 N, which is impressive contrast with O. monticola’s body weight.

Corrective Jaw Surgery

MedlinePlus Videos and Cool Tools

... Jaw Surgery Download Download the ebook for further information Corrective jaw, or orthognathic surgery is performed by ... your treatment. Correction of Common Dentofacial Deformities ​ ​ The information provided here is not intended as a substitute ...

Jaw lever analysis of Hawaiian gobioid stream fishes: a simulation study of morphological diversity and functional performance.

PubMed

Maie, Takashi; Schoenfuss, Heiko L; Blob, Richard W

2009-08-01

Differences in feeding behavior and performance among the five native Hawaiian gobioid stream fishes (Sicyopterus stimpsoni, Lentipes concolor, Awaous guamensis, Stenogobius hawaiiensis, and Eleotris sandwicensis) have been proposed based on the skeletal anatomy of their jaws and dietary specialization. However, performance of the feeding apparatus likely depends on the proportions and configurations of the jaw muscles and the arrangement of the jaw skeleton. We used a published mathematical model of muscle function to evaluate potential differences in jaw closing performance and their correlations with morphology among these species. For example, high output force calculated for the adductor mandibulae muscles (A2 and A3) of both A. guamensis and E. sandwicensis matched expectations based on the morphology of these species because these muscles are larger than in the other species. In contrast, Stenogobius hawaiiensis exhibited an alternative morphological strategy for achieving high relative output forces of both A2 and A3, in which the placement and configuration of the muscles conveyed high mechanical advantage despite only moderate cross-sectional areas. These differing anatomical pathways to similar functional performance suggest a pattern of many-to-one mapping of morphology to performance. In addition, a functional differentiation between A2 and A3 was evident for all species, in which A2 was better suited for producing forceful jaw closing and A3 for rapid jaw closing. Thus, the diversity of feeding performance of Hawaiian stream gobies seems to reflect a maintenance of functional breadth through the retention of some primitive traits in combination with novel functional capacities in several species. (c) 2009 Wiley-Liss, Inc.

Orthodontic treatment-induced temporal alteration of jaw-opening reflex excitability.

PubMed

Sasaki, Au; Hasegawa, Naoya; Adachi, Kazunori; Sakagami, Hiroshi; Suda, Naoto

2017-10-01

The impairment of orofacial motor function during orthodontic treatment needs to be addressed, because most orthodontic patients experience pain and motor excitability would be affected by pain. In the present study, the temporal alteration of the jaw-opening reflex excitability was investigated to determine if orthodontic treatment affects orofacial motor function. The excitability of jaw-opening reflex evoked by electrical stimulation on the gingiva and recorded bilaterally in the anterior digastric muscles was evaluated at 1 (D1), 3 (D3), and 7 days (D7) after orthodontic force application to the teeth of right side; morphological features (e.g., osteoclast genesis and tooth movement) were also evaluated. To clarify the underlying mechanism of orthodontic treatment-induced alteration of orofacial motor excitability, analgesics were administrated for 1 day. At D1 and D3, orthodontic treatment significantly decreased the threshold for inducing the jaw-opening reflex but significantly increased the threshold at D7. Other parameters of the jaw-opening reflex were also evaluated (e.g., latency, duration and area under the curve of anterior digastric muscles activity), and only the latency of the D1 group was significantly different from that of the other groups. Temporal alteration of the jaw-opening reflex excitability was significantly correlated with changes in morphological features. Aspirin (300 mg·kg -1 ·day -1 ) significantly increased the threshold for inducing the jaw-opening reflex, whereas a lower dose (75-150 mg·kg -1 ·day -1 ) of aspirin or acetaminophen (300 mg·kg -1 ·day -1 ) failed to alter the jaw-opening reflex excitability. These results suggest that an increase of the jaw-opening reflex excitability can be induced acutely by orthodontic treatment, possibly through the cyclooxygenase activation. NEW & NOTEWORTHY It is well known that motor function is affected by pain, but the effect of orthodontic treatment-related pain on the trigeminal

Myoelectric manifestations of jaw elevator muscle fatigue and recovery in healthy and TMD subjects.

PubMed

Castroflorio, T; Falla, D; Tartaglia, G M; Sforza, C; Deregibus, A

2012-09-01

The effects of muscle pain and fatigue on the control of jaw elevator muscles are not well known. Furthermore, the myoelectric manifestations of fatigue and recovery from fatigue in the masticatory muscles are not reported in literature. The main aims of this study were (i) to evaluate the possible use of surface electromyography (sEMG) as an objective measure of fatigue of the jaw elevator muscles, (ii) to compare the myoelectric manifestations of fatigue in the temporalis anterior and masseter muscles bilaterally, (iii) to assess recovery of the investigated muscles after an endurance test and (iv) to compare fatigue and recovery of the jaw elevator muscles in healthy subjects and patients with muscle-related temporomandibular disorders (TMD). The study was performed on twenty healthy volunteers and eighteen patients with muscle-related TMD. An intra-oral compressive-force sensor was used to measure the voluntary contraction forces close to the intercuspal position and to provide visual feedback of submaximal forces to the subject. Surface EMG signals were recorded with linear electrode arrays during isometric contractions at 20%, 40%, 60% and 80% of the maximum voluntary contraction force, during an endurance test and during the recovery phase. The results showed that (i) the slope of the mean power spectral frequency (MNF) and the initial average rectified value (ARV) could be used to monitor fatigue of the jaw elevators, (ii) the temporalis anterior and masseter muscle show the same myoelectric manifestations of fatigue and recovery and (iii) the initial values of MNF and ARV were lower in patients with muscle-related TMD. The assessment of myoelectric manifestations of fatigue in the masticatory muscles may assist in the clinical assessment of TMDs. © 2012 Blackwell Publishing Ltd.

Self-aligning lathe chuck jaws

DOEpatents

Not Available

1980-08-26

A lathe chuck jaw for a lathe chuck having a radially moving actuator which radially moves the jaw into and out from the workpiece is described. A jaw base part is rigidly connected to the actuator. A jaw shoe part is rotatably attached to the base part. The shoe part has a workpiece-conforming surface which can hold the workpiece. The rotatable attachment of the shoe part allows it to match the general orientation of the workpiece, including a nonlongitudinal orientation due to a workpiece's imperfect shape.

Self-aligning lathe chuck jaws

DOEpatents

Peterson, William R.

1982-01-01

A lathe chuck jaw for a lathe chuck having a radially moving actuator which radially moves the jaw in to and out from the workpiece. A jaw base part is rigidly connected to the actuator. A jaw shoe part is rotatably attached to the base part. The shoe part has a workpiece-comforming surface which can hold the workpiece. The rotatable attachment of the shoe part allows it to match the general orientation of the workpiece, including a nonlongitudinal orientation due to a workpiece's imperfect shape.

Successful treatment of open jaw and jaw deviation dystonia with botulinum toxin using a simple intraoral approach.

PubMed

Moscovich, Mariana; Chen, Zhongxing Peng; Rodriguez, Ramon

2015-03-01

Oromandibular dystonia (OMD) is a focal dystonia that involves the mouth, jaw, and/or tongue. It can be classified as idiopathic, tardive dystonia or secondary to other neurological disorders and subdivided into jaw opening, jaw closing, jaw deviation and lip pursing. The muscles involved in jaw opening dystonia are usually the digastrics and lateral pterygoids. It is known that the lateral pterygoids may be approached both internally and externally. The external approach is the most common; however neurologists experienced in treating patients with botulinum toxin can safely and with no extra cost perform the intraoral procedure. We report our experience in the treatment of jaw opening and jaw deviation dystonia using the intraoral injection approach. Eight patients were selected from the University of Florida with a clinical diagnosis of open jaw/jaw deviation dystonia. All of them were injected with onabotulinum toxin A using the internal approach and the clinical global impression scale was applied. The mean age of the patients was 67 (standard deviation [SD] 10.2) years, with a disease duration of 10.2 (SD 7.7) years and the mean distance they traveled to our institution was 448 km (278 miles). After treatment, six patients scored as very much improved in the clinical global impression scale and two patients scored as much improved. Only one patient reported an adverse event of nasal speech following one of the injections that improved after 4 weeks. Botulinum toxin injections for open jaw/jaw deviation dystonia can be safely performed with the intraoral approach without the need of special devices other than electromyography. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Jaws of amphibians and reptiles].

PubMed

Tanimoto, Masahiro

2005-04-01

Big jaws of amphibians and reptiles are mainly treated in this article. In amphibians enlarged skulls are for the big jaw in contrast with human's skulls for the brain. For example, famous fossils of Homo diluvii testis are ones of salamanders in fact. In reptiles, mosasaur jaws and teeth and their ecology are introduced for instance.

Broken or dislocated jaw

MedlinePlus

... broken or dislocated jaw requires prompt medical attention. Emergency symptoms include difficulty breathing or heavy bleeding. ... safety equipment, such as a helmet when playing football, or using ... can prevent or minimize some injuries to the face or jaw.

Force and Strength Analysis of the Reel with Jaw of Torsion-bar Spring

NASA Astrophysics Data System (ADS)

Ma, Ke; Liu, Weiqi; Wang, Jiawei; Gu, Le

2017-06-01

Structure characteristics and working principle of the reel with jaw of torsion-bar spring are introduced. The reel can not only eliminate the leakage risks of hydraulic jaw, but also reduce the investment cost of enterprises and improve the surface quality of the products. The static analysis of mandrel, sector plate and oblique wedge were conducted, and the main data of stress distribution and deformation were obtained, which provide a reliable theoretical basis for the design and optimization of the reel. The research results show that the external support has a great effect on the stress and deformation of the mandrel. With the increase of the weight of steel stress increases, the drum deformation increases, but the analysis of the position of maximum stress, can be obtained to drum stress and deformation is the main reason of excessive bending moment caused by heavy steel rolls. The bending moment and deformation can be reduced significantly at the end of the steel coil, which can effectively improve the service life of the drum.

21 CFR 872.2060 - Jaw tracking device.

Code of Federal Regulations, 2014 CFR

2014-04-01

...) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.2060 Jaw tracking device. (a) Jaw tracking device... Controls Guidance Document: Dental Sonography and Jaw Tracking Devices.” [68 FR 67367, Dec. 2, 2003] ...

Swiveling Lathe Jaw Concept for Holding Irregular Pieces

NASA Technical Reports Server (NTRS)

David, J.

1966-01-01

Clamp holds irregularly shaped pieces in lathe chuck without damage and eliminates excessive time in selecting optimum mounting. Interchangeable jaws ride in standard jaw slots but swivel so that the jaw face bears evenly against the workpiece regardless of contour. The jaws can be used on both engine and turret lathes.

Parrotfish grazing ability: interspecific differences in relation to jaw-lever mechanics and relative weight of adductor mandibulae on an Okinawan coral reef

PubMed Central

2016-01-01

Parrotfishes (family Labridae: Scarini) are regarded to have important roles for maintaining the ecosystem balance in coral reefs due to their removal of organic matter and calcic substrates by grazing. The purpose of the present study was to clarify the interspecific differences in grazing ability of five parrotfish species (Chlorurus sordidus, C. bowersi, Scarus rivulatus, S. niger and S. forsteni) in relation to interspecific differences in jaw-lever mechanics and the relative weight of the adductor mandibulae (muscles operating jaw closing). The grazing ability was calculated by using stomach contents (CaCO3 weight/organic matter weight) defined as the grazing ability index (GAI). There were significant interspecific differences in GAI (C. sordidus = C. bowersi > S. rivulatus > S. niger = S. forsteni). Teeth of C. sordidus and C. bowersi were protrusive-shape whereas teeth of S. rivulatus, S. niger and S. forsteni were flat-shape. C. sordidus and C. bowersihave jaw-lever mechanics producing a greater biting force and have a larger weight of adductor mandibulae. S. rivulatus has jaw-lever mechanics producing a greater biting force but a smaller weight of adductor mandibulae that produce an intermediate biting force. In contrast, S. niger and S. forsteni have jaw-lever mechanics producing a lesser biting force and have a smaller weight of adductor mandibulae. Feeding rates and foray size of S. rivulatus, S. niger and S. forsteni were greater than C. sordidus and C. bowersi. The degree in bioerosion (GAI × feeding rate) was the largest for S. rivulatusand the smallest for S. forsteni. The degree in bioerosion for C. sordidus was larger than S. niger whereas relatively equal between C. bowersi and S. niger. These results suggest that interspecific difference in GAI was explained by interspecific differences in teeth shape, jaw-lever mechanics and relative weight of adductor mandibulae. The interspecific difference in the degree of bioerosion suggests the

Parrotfish grazing ability: interspecific differences in relation to jaw-lever mechanics and relative weight of adductor mandibulae on an Okinawan coral reef.

PubMed

Nanami, Atsushi

2016-01-01

Parrotfishes (family Labridae: Scarini) are regarded to have important roles for maintaining the ecosystem balance in coral reefs due to their removal of organic matter and calcic substrates by grazing. The purpose of the present study was to clarify the interspecific differences in grazing ability of five parrotfish species (Chlorurus sordidus, C. bowersi, Scarus rivulatus, S. niger and S. forsteni) in relation to interspecific differences in jaw-lever mechanics and the relative weight of the adductor mandibulae (muscles operating jaw closing). The grazing ability was calculated by using stomach contents (CaCO3 weight/organic matter weight) defined as the grazing ability index (GAI). There were significant interspecific differences in GAI (C. sordidus = C. bowersi > S. rivulatus > S. niger = S. forsteni). Teeth of C. sordidus and C. bowersi were protrusive-shape whereas teeth of S. rivulatus, S. niger and S. forsteni were flat-shape. C. sordidus and C. bowersihave jaw-lever mechanics producing a greater biting force and have a larger weight of adductor mandibulae. S. rivulatus has jaw-lever mechanics producing a greater biting force but a smaller weight of adductor mandibulae that produce an intermediate biting force. In contrast, S. niger and S. forsteni have jaw-lever mechanics producing a lesser biting force and have a smaller weight of adductor mandibulae. Feeding rates and foray size of S. rivulatus, S. niger and S. forsteni were greater than C. sordidus and C. bowersi. The degree in bioerosion (GAI × feeding rate) was the largest for S. rivulatusand the smallest for S. forsteni. The degree in bioerosion for C. sordidus was larger than S. niger whereas relatively equal between C. bowersi and S. niger. These results suggest that interspecific difference in GAI was explained by interspecific differences in teeth shape, jaw-lever mechanics and relative weight of adductor mandibulae. The interspecific difference in the degree of bioerosion suggests the

21 CFR 872.2060 - Jaw tracking device.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Jaw tracking device. 872.2060 Section 872.2060 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.2060 Jaw tracking device. (a) Jaw tracking device...

21 CFR 872.2060 - Jaw tracking device.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Jaw tracking device. 872.2060 Section 872.2060 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.2060 Jaw tracking device. (a) Jaw tracking device...

21 CFR 872.2060 - Jaw tracking device.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Jaw tracking device. 872.2060 Section 872.2060 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.2060 Jaw tracking device. (a) Jaw tracking device...

21 CFR 872.2060 - Jaw tracking device.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Jaw tracking device. 872.2060 Section 872.2060 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.2060 Jaw tracking device. (a) Jaw tracking device...

Analysis of the bite force and mechanical design of the feeding mechanism of the durophagous horn shark Heterodontus francisci.

PubMed

Huber, Daniel R; Eason, Thomas G; Hueter, Robert E; Motta, Philip J

2005-09-01

Three-dimensional static equilibrium analysis of the forces generated by the jaw musculature of the horn shark Heterodontus francisci was used to theoretically estimate the maximum force distributions and loadings on its jaws and suspensorium during biting. Theoretical maximum bite force was then compared with bite forces measured (1) voluntarily in situ, (2) in restrained animals and (3) during electrical stimulation of the jaw adductor musculature of anesthetized sharks. Maximum theoretical bite force ranged from 128 N at the anteriormost cuspidate teeth to 338 N at the posteriormost molariform teeth. The hyomandibula, which connects the posterior margin of the jaws to the base of the chondrocranium, is loaded in tension during biting. Conversely, the ethmoidal articulation between the palatal region of the upper jaw and the chondrocranium is loaded in compression, even during upper jaw protrusion, because H. francisci's upper jaw does not disarticulate from the chondrocranium during prey capture. Maximum in situ bite force averaged 95 N for free-swimming H. francisci, with a maximum of 133 N. Time to maximum force averaged 322 ms and was significantly longer than time away from maximum force (212 ms). Bite force measurements from restrained individuals (187 N) were significantly greater than those from free-swimming individuals (95 N) but were equivalent to those from both theoretical (128 N) and electrically stimulated measurements (132 N). The mean mass-specific bite of H. francisci was greater than that of many other vertebrates and second highest of the cartilaginous fishes that have been studied. Measuring bite force on restrained sharks appears to be the best indicator of maximum bite force. The large bite forces and robust molariform dentition of H. francisci correspond to its consumption of hard prey.

Experimental masseter muscle pain alters jaw-neck motor strategy.

PubMed

Wiesinger, B; Häggman-Henrikson, B; Hellström, F; Wänman, A

2013-08-01

A functional integration between the jaw and neck regions has been demonstrated during normal jaw function. The effect of masseter muscle pain on this integrated motor behaviour in man is unknown. The aim of this study was to investigate the effect of induced masseter muscle pain on jaw-neck movements during a continuous jaw opening-closing task. Sixteen healthy men performed continuous jaw opening-closing movements to a target position, defined as 75% of the maximum jaw opening. Each subject performed two trials without pain (controls) and two trials with masseter muscle pain, induced with hypertonic saline as a single injection. Simultaneous movements of the mandible and the head were registered with a wireless optoelectronic three-dimensional recording system. Differences in movement amplitudes between trials were analysed with Friedman's test and corrected Wilcoxon matched pairs test. The head movement amplitudes were significantly larger during masseter muscle pain trials compared with control. Jaw movement amplitudes did not differ significantly between any of the trials after corrected Wilcoxon tests. The ratio between head and jaw movement amplitudes was significantly larger during the first pain trial compared with control. Experimental masseter muscle pain in humans affected integrated jaw-neck movements by increasing the neck component during continuous jaw opening-closing tasks. The findings indicate that pain can alter the strategy for jaw-neck motor control, which further underlines the functional integration between the jaw and neck regions. This altered strategy may have consequences for development of musculoskeletal pain in the jaw and neck regions. © 2012 European Federation of International Association for the Study of Pain Chapters.

The Covidien LigaSure Maryland Jaw Device.

PubMed

Zaidi, Nisar; Glover, Anthony R; Sidhu, Stanley B

2015-03-01

Since its invention nearly 20 years ago, the Covidien LigaSure device along with its ForceTriad generator has dominated the Electrothermal Bipolar Vessel Sealing market. The LigaSure was used for surgical procedures, both open and laparoscopic. The purpose of this review is to provide evidence of the safety and utility of the LigaSure device compared to more traditional means of hemostasis and its ultrasonic competitor, particularly in laparoscopic applications. We will provide evidence related to electrothermal bipolar vessel sealing in general and look specifically at Covidien's newest product, the LigaSure Maryland Jaw Device.

The jaw is a second-class lever in Pedetes capensis (Rodentia: Pedetidae)

PubMed Central

2017-01-01

The mammalian jaw is often modelled as a third-class lever for the purposes of biomechanical analyses, owing to the position of the resultant muscle force between the jaw joint and the teeth. However, it has been proposed that in some rodents the jaws operate as a second-class lever during distal molar bites, owing to the rostral position of the masticatory musculature. In particular, the infraorbital portion of the zygomatico-mandibularis (IOZM) has been suggested to be of major importance in converting the masticatory system from a third-class to a second-class lever. The presence of the IOZM is diagnostic of the hystricomorph rodents, and is particularly well-developed in Pedetes capensis, the South African springhare. In this study, finite element analysis (FEA) was used to assess the lever mechanics of the springhare masticatory system, and to determine the function of the IOZM. An FE model of the skull of P. capensis was constructed and loaded with all masticatory muscles, and then solved for biting at each tooth in turn. Further load cases were created in which each masticatory muscle was removed in turn. The analyses showed that the mechanical advantage of the springhare jaws was above one at all molar bites and very close to one during the premolar bite. Removing the IOZM or masseter caused a drop in mechanical advantage at all bites, but affected strain patterns and cranial deformation very little. Removing the ZM had only a small effect on mechanical advantage, but produced a substantial reduction in strain and deformation across the skull. It was concluded that the masticatory system of P. capensis acts as a second class lever during bites along almost the entire cheek tooth row. The IOZM is clearly a major contributor to this effect, but the masseter also has a part to play. The benefit of the IOZM is that it adds force without substantially contributing to strain or deformation of the skull. This may help explain why the hystricomorphous morphology

Deranged jaw-neck motor control in whiplash-associated disorders.

PubMed

Eriksson, Per-Olof; Zafar, Hamayun; Häggman-Henrikson, Birgitta

2004-02-01

Recent findings of simultaneous and well coordinated head-neck movements during single as well as rhythmic jaw opening-closing tasks has led to the conclusion that 'functional jaw movements' are the result of activation of jaw as well as neck muscles, leading to simultaneous movements in the temporomandibular, atlanto-occipital and cervical spine joints. It can therefore be assumed that disease or injury to any of these joint systems would disturb natural jaw function. To test this hypothesis, amplitudes, temporal coordination, and spatiotemporal consistency of concomitant mandibular and head-neck movements during single maximal jaw opening-closing tasks were analysed in 25 individuals suffering from whiplash-associated disorders (WAD) using optoelectronic movement recording technique. In addition, the relative durations for which the head position was equal to, leading ahead of, or lagging behind the mandibular position during the entire jaw opening-closing cycle were determined. Compared with healthy individuals, the WAD group showed smaller amplitudes, and changed temporal coordination between mandibular and head-neck movements. No divergence from healthy individuals was found for the spatiotemporal consistency or for the analysis during the entire jaw opening-closing cycle. These findings in the WAD group of a 'faulty', but yet consistent, jaw-neck behavior may reflect a basic importance of linked control of the jaw and neck sensory-motor systems. In conclusion, the present results suggest that neck injury is associated with deranged control of mandibular and head-neck movements during jaw opening-closing tasks, and therefore might compromise natural jaw function.

Morphology and mechanics of the teeth and jaws of white-spotted bamboo sharks (Chiloscyllium plagiosum).

PubMed

Ramsay, Jason B; Wilga, Cheryl D

2007-08-01

The teeth of white-spotted bamboo sharks (Chiloscyllium plagiosum) are used to clutch soft-bodied prey and crush hard prey; however, the dual function is not evident from tooth morphology alone. Teeth exhibit characteristics that are in agreement with a clutching-type tooth morphology that is well suited for grasping and holding soft-bodied prey, but not for crushing hard prey. The dual role of this single tooth morphology is facilitated by features of the dental ligament and jaw joint. Tooth attachment is flexible and elastic, allowing movement in both sagittal and frontal planes. During prey capture spike-like tooth cusps pierce the flesh of soft prey, thereby preventing escape. When processing prey harder than the teeth can pierce the teeth passively depress, rotating inward towards the oral cavity such that the broader labial faces of the teeth are nearly parallel to the surface of the jaws and form a crushing surface. Movement into the depressed position increases the tooth surface area contacting prey and decreases the total stress applied to the tooth, thereby decreasing the risk of structural failure. This action is aided by a jaw joint that is ventrally offset from the occlusal planes of the jaws. The offset joint position allows many teeth to contact prey simultaneously and orients force vectors at contact points between the jaws and prey in a manner that shears or rolls prey between the jaws during a bite, thus, aiding in processing while reducing forward slip of hard prey from the mouth. Together the teeth, dental ligament, and jaws form an integrated system that may be beneficial to the feeding ecology of C. plagiosum, allowing for a diet that includes prey of varying hardness and elusiveness. (c) 2007 Wiley-Liss, Inc.

Masticatory motor patterns in ungulates: a quantitative assessment of jaw-muscle coordination in goats, alpacas and horses.

PubMed

Williams, Susan H; Vinyard, Christopher J; Wall, Christine E; Hylander, William L

2007-04-01

We investigated patterns of jaw-muscle coordination during rhythmic mastication in three species of ungulates displaying the marked transverse jaw movements typical of many large mammalian herbivores. In order to quantify consistent motor patterns during chewing, electromyograms were recorded from the superficial masseter, deep masseter, posterior temporalis and medial pterygoid muscles of goats, alpacas and horses. Timing differences between muscle pairs were evaluated in the context of an evolutionary model of jaw-muscle function. In this model, the closing and food reduction phases of mastication are primarily controlled by two distinct muscle groups, triplet I (balancing-side superficial masseter and medial pterygoid and working-side posterior temporalis) and triplet II (working-side superficial masseter and medial pterygoid and balancing-side posterior temporalis), and the asynchronous activity of the working- and balancing-side deep masseters. The three species differ in the extent to which the jaw muscles are coordinated as triplet I and triplet II. Alpacas, and to a lesser extent, goats, exhibit the triplet pattern whereas horses do not. In contrast, all three species show marked asynchrony of the working-side and balancing-side deep masseters, with jaw closing initiated by the working-side muscle and the balancing-side muscle firing much later during closing. However, goats differ from alpacas and horses in the timing of the balancing-side deep masseter relative to the triplet II muscles. This study highlights interspecific differences in the coordination of jaw muscles to influence transverse jaw movements and the production of bite force in herbivorous ungulates.

Biomechanical implications of lateral pterygoid contribution to biting and jaw opening in humans.

PubMed

Osborn, J W

1995-12-01

The contributions of the lateral pterygoid muscle to a variety of different tasks were analysed by a linear programming mode based on the equations for static equilibrium in three dimensions and containing 12 muscles. The model was used to study lateral pterygoid activity at maximum bite force (MBF) for changes in (i) the direction and point of application of the bite force, (ii) the orientation of the masseter and medial pterygoid muscles and (iii) the slope of the articular eminence (glenoid slope). The effects on MBF of removing one or both lateral pterygoids were also examined. Lateral pterygoid provided a very important indirect contribution to some clenching forces. Under some conditions removing one lateral pterygoid muscle (simulating guarding an injured muscle) halved the MBF. Its activity at MBF was reduced as masseter was tilted more forward, the glenoid slope was made more horizontal and the bite force was made more vertical. The muscle helped to oppose (balance) the horizontal reaction forces at the bite point and joints, which potentially pushed the condyle backward. A balancing muscle is now defined as one (like lateral pterygoid) whose activity increases the output force by far more than its direct contribution to that force. In a larger model containing 16 muscles, every muscle was most active when its line of action was parallel to the output force. Finally, in a model which divided lateral pterygoid into superior and inferior heads, activity suddenly switched from the superior head to the inferior head when the angle of opening changed from 120 degrees (forward from the vertical) to 140 degrees.

Small vertical changes in jaw relation affect motor unit recruitment in the masseter.

PubMed

Terebesi, S; Giannakopoulos, N N; Brüstle, F; Hellmann, D; Türp, J C; Schindler, H J

2016-04-01

Strategies for recruitment of masseter muscle motor units (MUs), provoked by constant bite force, for different vertical jaw relations have not previously been investigated. The objective of this study was to analyse the effect of small changes in vertical jaw relation on MU recruitment behaviour in different regions of the masseter during feedback-controlled submaximum biting tasks. Twenty healthy subjects (mean age: 24·6 ± 2·4 years) were involved in the investigation. Intra-muscular electromyographic (EMG) activity of the right masseter was recorded in different regions of the muscle. MUs were identified by the use of decomposition software, and root-mean-square (RMS) values were calculated for each experimental condition. Six hundred and eleven decomposed MUs with significantly (P < 0·001) different jaw relation-specific recruitment behaviour were organised into localised MU task groups. MUs with different task specificity in seven examined tasks were observed. The RMS EMG values obtained from the different recording sites were also significantly (P < 0·01) different between tasks. Overall MU recruitment was significantly (P < 0·05) greater in the deep masseter than in the superficial muscle. The number of recruited MUs and the RMS EMG values decreased significantly (P < 0·01) with increasing jaw separation. This investigation revealed differential MU recruitment behaviour in discrete subvolumes of the masseter in response to small changes in vertical jaw relations. These fine-motor skills might be responsible for its excellent functional adaptability and might also explain the successful management of temporomandibular disorder patients by somatic intervention, in particular by the use of oral splints. © 2015 John Wiley & Sons Ltd.

Appraisal of jaw swellings in a Nigerian tertiary healthcare facility.

PubMed

Lasisi, Taye J; Adisa, Akinyele O; Olusanya, Adeola A

2013-02-01

The mandible and maxilla can be the site of myriads of lesions that may be categorized as neoplastic, cystic, reactive and infective or inflammatory. Literature reviewing jaw swellings in an amalgamated fashion are uncommon, probably because aetiologies for these swellings are varied. However, to appreciate their relative relationship, it is essential to evaluate the clinico-pathologic profile of jaw swellings. The aim of this appraisal is to describe the array of jaw swellings seen at our hospital from 1990 to 2011, to serve as a reference database. Biopsy records of all histologically diagnosed cases of jaw swellings seen at the department of Oral Pathology, University College Hospital between January 1990 and December 2011 were retrieved, coded and inputted into SPSS version 20. Data on prevalence, age, sex, site and histological diagnosis were analysed descriptively for each category of jaw swellings. All patients below 16 years were regarded as children. A total of 638 jaw swellings were recorded in the 22-year study period. The Non Odontogenic Tumours (NOT) were the commonest, accounting for 46.2% of all jaw swellings. Odontogenic Tumours (OT) formed 45% of all adult jaw swelling while it formed 25.2% in children and adolescents. Ameloblastoma was the commonest while the most common NOT was ossifying fibroma (OF). Chronic osteomyelitis of the jaws was about 6 times commoner in adult females than males and mostly involved the mandible. The most common malignant jaw swelling was Burkitts' lymphoma (BL) that was about 7 times more in children than adults. Osteogenic sarcoma was the most common malignancy in adults. Jaw swellings are extensively varied in types and pattern of occurrence. This study has categorized jaw swellings in a simple but comprehensive fashion to allow for easy referencing in local and international data acquisition and epidemiological comparison. Key words:Jaw swellings, odontogenic, Nigeria.

Jaw-phonatory coordination in chronic developmental stuttering.

PubMed

Loucks, Torrey M J; De Nil, Luc F; Sasisekaran, Jayanthi

2007-01-01

A deficiency in sensorimotor integration in a person who stutters may be a factor in the pathophysiology of developmental stuttering. To test oral sensorimotor function in adults who stutter, we used a task that requires the coordination of a jaw-opening movement with phonation onset. The task was adapted from previous limb coordination studies, which show that movement coordination depends on intact proprioception. We hypothesized that adult stutterers would show deficient jaw-phonatory coordination relative to control participants. The task required initiation of phonation as a jaw-opening movement passed through a narrow spatial target. Target amplitude and jaw movement speed were varied. The stuttering group showed significantly higher movement error and spatial variability in jaw-phonatory coordination compared to the control group, but group differences in movement velocity or duration were not found. The aberrant jaw-phonatory coordination of the stuttering participants suggests that stuttering is associated with an oral proprioceptive limitation, although, the findings are also consistent with a motor control deficit. As a result of this activity, reader will (1) learn about a hypothesis and evidence supporting the view that a sensorimotor deficit contributes to chronic developmental stuttering and (2) will obtain information about the role of proprioception in multi-articulatory coordination and how it can be tested using an oral-phonatory coordination task.

Frequent jaw-face pain in chronic Whiplash-Associated Disorders.

PubMed

Häggman-Henrikson, Birgitta; Grönqvist, Johan; Eriksson, Per-Olof

2011-01-01

Chronic Whiplash-Associated Disorders (WAD) present with frequent pain in the neck, head and shoulder regions but the presence of frequent jaw-face pain is unclear. The aim of the study was to investigate the frequency of jaw-face pain, pain in other regions, and general symptoms in chronic WAD patients. Fifty whiplash-patients and 50 healthy age- and sex-matched controls were examined by questionnaire for pain in the jaw-face, pain in other regions and other symptoms. In contrast to healthy, a majority of the WAD patients (88%) reported frequent pain in the jaw-face, in addition to frequent pain in the neck (100%), shoulders (94%), head (90%) and back (72%). The WAD patients also reported stiffness and numbness in the jaw-face region, and frequent general symptoms such as balance problems, stress and sleep disturbances. The result suggests that frequent pain in the jaw-face can be part of the spectrum of symptoms in chronic WAD.The finding of self-reported numbness in the jaw-face indicates disturbed trigeminal nerve function and merits further investigation. We conclude that assessment of WAD should include pain in the jaw-face region. A multidisciplinary rehabilitation program including dentists, preferably specialized in the area of orofacial pain, should be advocated after whiplash injury.

Bisphosphonate Therapy (and Osteonecrosis of the Jaw)

MedlinePlus

... or other invasive dental procedures, a phenomenon called osteonecrosis of the jaw (see Right and note area ... doctors agree that there is an association between osteonecrosis of the jaw and bisphosphonates, although the drugs ...

Self-aligning fixture used in lathe chuck jaw refacing

NASA Technical Reports Server (NTRS)

Linn, C. C.

1965-01-01

Self-aligning tool positions and rigidly holds lathe chuck jaws for refacing and truing of the clamping surface. The jaws clamp the fixture in the manner of clamping a workpiece. The fixture can be modified to accommodate four-jawed checks.

Additively manufactured sub-periosteal jaw implants.

PubMed

Mommaerts, M Y

2017-07-01

Severe bone atrophy jeopardizes the success of endosseous implants. This technical note aims to present the innovative concept of additively manufactured sub-periosteal jaw implants (AMSJIs). Digital datasets of the patient's jaws and wax trial in occlusion are used to segment the bone and dental arches, for the design of a sub-periosteal frame and abutments in the optimal location related to the dental arch and for the design of the suprastructure. The implants and suprastructure are three-dimensionally (3D) printed in titanium alloy. The provisional denture is 3D-printed in polymer. AMSJIs offer an alternative approach for patients with extreme jaw bone atrophy. This report refers to the use of this technique for full maxillary rehabilitation, but partial defects in either jaw and extended post-resection defects may also be approached using the same technique. This customized, prosthesis-driven reverse-engineering approach avoids bone grafting and provides immediate functional restoration with one surgical session. Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Surface electromyographic evaluation of jaw muscles in children with unilateral crossbite and lateral shift in the early mixed dentition. Sexual dimorphism

PubMed Central

Lenguas, Leticia; Alarcón, José-Antonio; Venancio, Filipa; Kassem, Marta

2012-01-01

Objectives: To examine the activity of jaw muscles at rest and during maximal voluntary clenching (MVC) in children with unilateral posterior crossbite (UPXB) and functional lateral shift in the early mixed dentition and to evaluate sex differences. Material and Methods: The sample included 30 children (15 males, 15 females) aged 6 to 10 years old, with UPXB and functional mandibular lateral shift (≥1.5 mm) in the early mixed dentition. sEMG activity coming from the muscle areas (anterior temporalis [AT], posterior temporalis [PT], masseter [MA] and suprahyoid [SH]) were obtained from both the crossbite (XB) and noncrossbite (NONXB) sides at mandibular rest position. sEMG acti-vity of the bilateral AT and MA muscles sides was obtained during MVC. Asymmetry and activity indexes were calculated for each muscle area at rest and during MVC; the MA/TA ratio during MVC was also determined. Results: At rest, no differences were found between sexes for any muscle areas or asymmetry and activity indexes. No differences were found between XB and NONXB sides. During MVC, however, significant sex differences were found in AT and MA activity, with higher sEMG values in males than in females, on both XB and NONXB sides. Asymmetry indexes, activity indexes and MA/AT ratios did not show significant differences between the sexes. Activity was symmetric both in males and in females. Conclusions: At rest, no sex differences were found, but during MVC males showed higher activity than did females in both XB and NONXB AT and MA muscle areas. Muscular activity was symmetrical at rest and during MVC in both sexes. Sexual dimorphism should be considered in the diagnosis and treatment of UPXB and lateral shift in the early mixed dentition. Key words:Unilateral crossbite, mandibular shift, jaw muscles, sEMG, early mixed dentition. PMID:22926468

The virtual craniofacial patient: 3D jaw modeling and animation.

PubMed

Enciso, Reyes; Memon, Ahmed; Fidaleo, Douglas A; Neumann, Ulrich; Mah, James

2003-01-01

In this paper, we present new developments in the area of 3D human jaw modeling and animation. CT (Computed Tomography) scans have traditionally been used to evaluate patients with dental implants, assess tumors, cysts, fractures and surgical procedures. More recently this data has been utilized to generate models. Researchers have reported semi-automatic techniques to segment and model the human jaw from CT images and manually segment the jaw from MRI images. Recently opto-electronic and ultrasonic-based systems (JMA from Zebris) have been developed to record mandibular position and movement. In this research project we introduce: (1) automatic patient-specific three-dimensional jaw modeling from CT data and (2) three-dimensional jaw motion simulation using jaw tracking data from the JMA system (Zebris).

Morphometric assessment of pterosaur jaw disparity

NASA Astrophysics Data System (ADS)

Navarro, Charlie A.; Martin-Silverstone, Elizabeth; Stubbs, Thomas L.

2018-04-01

Pterosaurs were a successful group of Mesozoic flying reptiles. They were the first vertebrate group to achieve powered flight and varied enormously in morphology and ecology, occupying a variety of niches and developing specialized feeding strategies. Ecomorphological principles suggest this variation should be reflected by great morphological diversity in the lower jaw, given that the mandible served as the primary apparatus for prey acquisition. Here we present the first study of mandibular shape disparity in pterosaurs and aim to characterize major aspects of variation. We use a combination of geometric morphometric approaches, incorporating both outline analysis using elliptical Fourier analysis and semi-landmark approaches. Our results show that morphological convergence is prevalent and many pterosaurs, belonging to diverse dietary groups and subclades, overlap in morphospace and possessed relatively simple `rod-shaped' jaws. There is no clear trend of size distributions in pterosaur mandibular morphospace, and larger forms are widely distributed. Additionally, there is limited functional signal within pterosaur lower jaw morphospace. Instead, the development of a large anterior ventral crest represents the major component of disparity. This suggests that a socio-sexual trait was a key driver for innovation in pterosaur lower jaw shape.

Morphometric assessment of pterosaur jaw disparity.

PubMed

Navarro, Charlie A; Martin-Silverstone, Elizabeth; Stubbs, Thomas L

2018-04-01

Pterosaurs were a successful group of Mesozoic flying reptiles. They were the first vertebrate group to achieve powered flight and varied enormously in morphology and ecology, occupying a variety of niches and developing specialized feeding strategies. Ecomorphological principles suggest this variation should be reflected by great morphological diversity in the lower jaw, given that the mandible served as the primary apparatus for prey acquisition. Here we present the first study of mandibular shape disparity in pterosaurs and aim to characterize major aspects of variation. We use a combination of geometric morphometric approaches, incorporating both outline analysis using elliptical Fourier analysis and semi-landmark approaches. Our results show that morphological convergence is prevalent and many pterosaurs, belonging to diverse dietary groups and subclades, overlap in morphospace and possessed relatively simple 'rod-shaped' jaws. There is no clear trend of size distributions in pterosaur mandibular morphospace, and larger forms are widely distributed. Additionally, there is limited functional signal within pterosaur lower jaw morphospace. Instead, the development of a large anterior ventral crest represents the major component of disparity. This suggests that a socio-sexual trait was a key driver for innovation in pterosaur lower jaw shape.

Morphometric assessment of pterosaur jaw disparity

PubMed Central

Navarro, Charlie A.; Martin-Silverstone, Elizabeth

2018-01-01

Pterosaurs were a successful group of Mesozoic flying reptiles. They were the first vertebrate group to achieve powered flight and varied enormously in morphology and ecology, occupying a variety of niches and developing specialized feeding strategies. Ecomorphological principles suggest this variation should be reflected by great morphological diversity in the lower jaw, given that the mandible served as the primary apparatus for prey acquisition. Here we present the first study of mandibular shape disparity in pterosaurs and aim to characterize major aspects of variation. We use a combination of geometric morphometric approaches, incorporating both outline analysis using elliptical Fourier analysis and semi-landmark approaches. Our results show that morphological convergence is prevalent and many pterosaurs, belonging to diverse dietary groups and subclades, overlap in morphospace and possessed relatively simple ‘rod-shaped’ jaws. There is no clear trend of size distributions in pterosaur mandibular morphospace, and larger forms are widely distributed. Additionally, there is limited functional signal within pterosaur lower jaw morphospace. Instead, the development of a large anterior ventral crest represents the major component of disparity. This suggests that a socio-sexual trait was a key driver for innovation in pterosaur lower jaw shape. PMID:29765665

Introduction to the JAWS Program

NASA Technical Reports Server (NTRS)

Mccarthy, John

1987-01-01

The JAWS Project is the Joint Airport Weather Studies project conceived in 1980 jointly between the National Center for Atmospheric Research and the Univ. of Chicago. The objectives of the program are threefold: (1) Basic scientific characterization of the microbursts and the statistics of microbursts occurrence; (2) Detection and warning, using the Low Level Wind Shear Alert System (LLWSAS) operation and performance; and (3) Doppler radar and airborne systems. These goals and the operation of the JAWS system in general are discussed in detail.

The evolutionary origin of jaw yaw in mammals

PubMed Central

Grossnickle, David M.

2017-01-01

Theria comprises all but three living mammalian genera and is one of the most ecologically pervasive clades on Earth. Yet, the origin and early history of therians and their close relatives (i.e., cladotherians) remains surprisingly enigmatic. A critical biological function that can be compared among early mammal groups is mastication. Morphometrics and modeling analyses of the jaws of Mesozoic mammals indicate that cladotherians evolved musculoskeletal anatomies that increase mechanical advantage during jaw rotation around a dorsoventrally-oriented axis (i.e., yaw) while decreasing the mechanical advantage of jaw rotation around a mediolaterally-oriented axis (i.e., pitch). These changes parallel molar transformations in early cladotherians that indicate their chewing cycles included significant transverse movement, likely produced via yaw rotation. Thus, I hypothesize that cladotherian molar morphologies and musculoskeletal jaw anatomies evolved concurrently with increased yaw rotation of the jaw during chewing cycles. The increased transverse movement resulting from yaw rotation may have been a crucial evolutionary prerequisite for the functionally versatile tribosphenic molar morphology, which underlies the molars of all therians and is retained by many extant clades. PMID:28322334

Prevalence of symptoms associated with temporomandibular disorders in Hong Kong Chinese.

PubMed

Pow, E H; Leung, K C; McMillan, A S

2001-01-01

To estimate the prevalence of self-reported symptoms associated with temporomandibular disorders (TMD) and treatment-seeking in adult Chinese in Hong Kong. A telephone survey technique was used to identify 1,526 randomly selected Cantonese-speaking individuals aged 18 years or over. Standard questions were asked about joint and jaw muscle pain, jaw opening, and joint sounds. In addition, questions on tooth grinding and clenching, sleep patterns, and treatment-seeking behavior were posed. Jaw pain was reported by 33% of the population. Only 5% of them had frequent pain, with two thirds of this subgroup having moderate to severe symptoms. The prevalence of frequent problems with jaw opening and joint clicking was 0.3% and 1.8%, respectively. There were no gender-related differences in the reporting of TMD symptoms or related conditions. One percent of the Hong Kong Chinese population had TMD-related jaw pain that was of moderate or severe intensity and occurred frequently; 0.6% of the population had sought treatment for jaw pain, impaired jaw opening, or joint clicking that occurred often in the previous year.

Multiple developmental mechanisms regulate species-specific jaw size

PubMed Central

Fish, Jennifer L.; Sklar, Rachel S.; Woronowicz, Katherine C.; Schneider, Richard A.

2014-01-01

Variation in jaw size during evolution has been crucial for the adaptive radiation of vertebrates, yet variation in jaw size during development is often associated with disease. To test the hypothesis that early developmental events regulating neural crest (NC) progenitors contribute to species-specific differences in size, we investigated mechanisms through which two avian species, duck and quail, achieve their remarkably different jaw size. At early stages, duck exhibit an anterior shift in brain regionalization yielding a shorter, broader, midbrain. We find no significant difference in the total number of pre-migratory NC; however, duck concentrate their pre-migratory NC in the midbrain, which contributes to an increase in size of the post-migratory NC population allocated to the mandibular arch. Subsequent differences in proliferation lead to a progressive increase in size of the duck mandibular arch relative to that of quail. To test the role of pre-migratory NC progenitor number in regulating jaw size, we reduced and augmented NC progenitors. In contrast to previous reports of regeneration by NC precursors, we find that neural fold extirpation results in a loss of NC precursors. Despite this reduction in their numbers, post-migratory NC progenitors compensate, producing a symmetric and normal-sized jaw. Our results suggest that evolutionary modification of multiple aspects of NC cell biology, including NC allocation within the jaw primordia and NC-mediated proliferation, have been important to the evolution of jaw size. Furthermore, our finding of NC post-migratory compensatory mechanisms potentially extends the developmental time frame for treatments of disease or injury associated with NC progenitor loss. PMID:24449843

Specification of jaw identity by the Hand2 transcription factor

PubMed Central

Funato, Noriko; Kokubo, Hiroki; Nakamura, Masataka; Yanagisawa, Hiromi; Saga, Yumiko

2016-01-01

Acquisition of the lower jaw (mandible) was evolutionarily important for jawed vertebrates. In humans, syndromic craniofacial malformations often accompany jaw anomalies. The basic helix-loop-helix transcription factor Hand2, which is conserved among jawed vertebrates, is expressed in the neural crest in the mandibular process but not in the maxillary process of the first branchial arch. Here, we provide evidence that Hand2 is sufficient for upper jaw (maxilla)-to-mandible transformation by regulating the expression of homeobox transcription factors in mice. Altered Hand2 expression in the neural crest transformed the maxillae into mandibles with duplicated Meckel’s cartilage, which resulted in an absence of the secondary palate. In Hand2-overexpressing mutants, non-Hox homeobox transcription factors were dysregulated. These results suggest that Hand2 regulates mandibular development through downstream genes of Hand2 and is therefore a major determinant of jaw identity. Hand2 may have influenced the evolutionary acquisition of the mandible and secondary palate. PMID:27329940

Jaw muscles in older overdenture patients.

PubMed

Newton, James P; McManus, Frank C; Menhenick, Stephen

2004-03-01

To determine, using computer tomography (CT), whether the retention of a small number of teeth in the older adult used to support overdentures could affect the cross-sectional area (CSA) and X-ray density of two jaw closing muscles. Cross-sectional study of a group of older patients subdivided into dentate, edentulous and those wearing overdentures supported by two to five teeth. The sample consisted of 24 subjects aged 55-68 years. CSA and X-ray density of two jaw closing muscles, masseter and medial pterygoid were measured and evaluated using CT. There were no significant differences between left and right jaw muscles, but the CSA of the masseter muscles were significantly larger than the medial pterygoid muscles. The CSA of the masseter and medial pterygoid muscles was significantly smaller in edentulous subjects compared with dentate subjects but no significant difference was observed between subjects wearing overdentures and those with a natural dentition. No significant differences were observed with the X-ray density between different muscles or dental states. The retention of a small number of teeth in the older adult used to support overdentures appears to sustain the CSA of two jaw closing muscles and therefore could enhance these patients' masticatory ability compared with those who were edentulous.

Effects of grip force on median nerve deformation at different wrist angles

PubMed Central

Nakashima, Hiroki; Muraki, Satoshi

2016-01-01

The present study investigated the effects of grip on changes in the median nerve cross-sectional area (MNCSA) and median nerve diameter in the radial-ulnar direction (D1) and dorsal-palmar direction (D2) at three wrist angles. Twenty-nine healthy participants (19 men [mean age, 24.2 ± 1.6 years]; 10 women [mean age, 24.0 ± 1.6 years]) were recruited. The median nerve was examined at the proximal carpal tunnel region in three grip conditions, namely finger relaxation, unclenched fist, and clenched fist. Ultrasound examinations were performed in the neutral wrist position (0°), at 30°wrist flexion, and at 30°wrist extension for both wrists. The grip condition and wrist angle showed significant main effects (p < 0.01) on the changes in the MNCSA, D1, and D2. Furthermore, significant interactions (p < 0.01) were found between the grip condition and wrist angle for the MNCSA, D1, and D2. In the neutral wrist position (0°), significant reductions in the MNCSA, D1, and D2 were observed when finger relaxation changed to unclenched fist and clenched fist conditions. Clenched fist condition caused the highest deformations in the median nerve measurements (MNCSA, approximately −25%; D1, −13%; D2, −12%). The MNCSA was significantly lower at 30°wrist flexion and 30°wrist extension than in the neutral wrist position (0°) at unclenched fist and clenched fist conditions. Notably, clenched fist condition at 30°wrist flexion showed the highest reduction of the MNCSA (−29%). In addition, 30°wrist flexion resulted in a lower D1 at clenched fist condition. In contrast, 30°wrist extension resulted in a lower D2 at both unclenched fist and clenched fist conditions. Our results suggest that unclenched fist and clenched fist conditions cause reductions in the MNCSA, D1, and D2. More importantly, unclenched fist and clenched fist conditions at 30°wrist flexion and 30°wrist extension can lead to further deformation of the median nerve. PMID:27688983

Can short-term oral fine motor training affect precision of task performance and induce cortical plasticity of the jaw muscles?

PubMed

Zhang, Hong; Kumar, Abhishek; Kothari, Mohit; Luo, Xiaoping; Trulsson, Mats; Svensson, Krister G; Svensson, Peter

2016-07-01

The aim was to test the hypothesis that short-term oral sensorimotor training of the jaw muscles would increase the precision of task performance and induce neuroplastic changes in the corticomotor pathways, related to the masseter muscle. Fifteen healthy volunteers performed six series with ten trials of an oral sensorimotor task. The task was to manipulate and position a spherical chocolate candy in between the anterior teeth and split it into two equal halves. The precision of the task performance was evaluated by comparing the ratio between the two split halves. A series of "hold-and-split" tasks was also performed before and after the training. The hold force and split force along with the electromyographic (EMG) activity of jaw muscles were recorded. Motor-evoked potentials and cortical motor maps of the right masseter muscle were evoked by transcranial magnetic stimulation. There was a significant effect of series on the precision of the task performance during the short-term oral sensorimotor training (P < 0.002). The hold force during the "hold-and-split" task was significantly lower after training than before the short-term training (P = 0.011). However, there was no change in the split force and the EMG activity of the jaw muscles before and after the training. Further, there was a significant increase in the amplitude of the motor-evoked potentials (P < 0.016) and in the motor cortex map areas (P = 0.033), after the short-term oral sensorimotor training. Therefore, short-term oral sensorimotor task training increased the precision of task performance and induced signs of neuroplastic changes in the corticomotor pathways, related to the masseter muscle.

Fine morphology of the jaw apparatus of Puncturella noachina (Fissurellidae, Vetigastropoda).

PubMed

Vortsepneva, Elena; Ivanov, Dmitry; Purschke, Günter; Tzetlin, Alexander

2014-07-01

Jaws of various kinds occur in virtually all groups of Mollusca, except for Polyplacophora and Bivalvia. Molluscan jaws are formed by the buccal epithelium and either constitute a single plate, a paired formation or a serial structure. Buccal ectodermal structures in gastropods are rather different. They can be nonrenewable or having final growth, like the hooks in Clione (Gastropoda, Gymnosomata). In this case, they are formed by a single cell. Conversely, they can be renewable during the entire life span and in this case they are formed by a set of cells, like the formation of the radula. The fine structure of the jaws was studied in the gastropod Puncturella noachina. The jaw is situated in the buccal cavity and consists of paired elongated cuticular plates. On the anterior edge of each cuticular plate there are numerous longitudinally oriented rodlets disposed over the entire jaw surface and immersed into a cuticular matrix. The jaw can be divided into four zones situated successively toward the anterior edge: 1) the posterior area: the zone of formation of the thick cuticle covering the entire jaw and forming the electron-dense outer layer of the jaw plate; 2) the zone of rodlet formation; 3) the zone of rodlet arrangement; and 4) the anterior zone: the free scraping edge of the plate, or the erosion zone. In the general pattern of jaw formation, Puncturella noachina resembles Testudinalia tessulata (Patellogastropoda) studied previously. The basis of the jaw is a cuticular plate formed by the activity of the strongly developed microvillar apparatus of the gnathoepithelium. However, the mechanism of renewal of the jaw anterior part in P. noachina is much more complex as its scraping edge consists not just of a thick cuticular matrix rather than of a system of denticles being the projecting endings of rodlets. © 2014 Wiley Periodicals, Inc.

Epidemiology of the sarcomas of the jaws in a Peruvian population

PubMed Central

Sacsaquispe-Contreras, Sonia J.; Morales-Vadillo, Rafael; Sánchez Lihón, Juvenal

2012-01-01

Objective: Analysis of the clinical characteristics of patients with Sarcomas of the Jaws treated in the “Instituto Nacional de Enfermedades Neoplasicas. Dr. Eduardo Caceres Graziani” from 1952-2007. Study Design: Review of 155 clinical records of patients with Sarcomas of the Jaws and record of age, gender, size, location, clinical symptoms and signs, histopathological diagnoses and type of treatment. The data obtained were analyzed by means of Student’s statistical t-test, Fisher and Friedman’s test. Results: Analysis of 155 Sarcomas of the Jaws. The average age of patients was 36.8 years old (range: 1-80 years); the female gender was the most frequent (52.9%); the average tumor size was 5.5 cm; in upper jaw 54.84% occurred and 45.16% in the lower jaw; the predominant sign was facial asymmetry (87.74%) and the predominant symptom: pain (63.23%). The most frequent diagnosis was Osteosarcoma 50.3% followed by Chondrosarcoma 18%. Surgery plus radiation therapy was the treatment type of choice with 21.94% of cases. Conclusion: The results of this study demonstrate the delayed diagnosis and facial asymmetry and pain appear as the most important events for the diagnosis of Sarcomas of the Jaws. Key words: Sarcoma, jaw, jaw neoplasms, mouth neoplasms. PMID:22143684

[Size of lower jaw as an early indicator of skeletal class III development].

PubMed

Stojanović, Zdenka; Nikodijević, Angelina; Udovicić, Bozidar; Milić, Jasmina; Nikolić, Predrag

2008-08-01

Malocclusion of skeletal class III is a complex abnormality, with a characteristic sagital position of the lower jaw in front of the upper one. A higher level of prognatism of the lower jaw in relation to the upper one can be the consequence of its excessive length. The aim of this study was to find the differences in the length of the lower jaw in the children with skeletal class III and the children with normal sagital interjaw relation (skeletal class I) in the period of mixed dentition. After clinical and x-ray diagnostics, profile tele-x-rays of the head were analyzed in 60 examinees with mixed dentition, aged from 6 to 12 years. The examinees were divided into two groups: group 1--the children with skeletal class III and group 2--the children with skeletal class I. The length of the lower jaw, upper jaw and cranial base were measured. The proportional relations between the lengths measured within each group were established and the level of difference in the lengths measured and their proportions between the groups were estimated. No significant difference between the groups was found in the body length, ramus and the total length of the lower jaw. Proportional relation between the body length and the length of the lower jaw ramus and proportional relation between the forward cranial base and the lower jaw body were not significantly different. A significant difference was found in proportional relations of the total length of the lower jaw with the total lengths of cranial base and the upper jaw and proportional relation of the length of the lower and upper jaw body. Of all the analyzed parameters, the following were selected as the early indicators of the development of skeletal class III on the lower jaw: greater total length of the lower jaw, proportional to the total lengths of cranial base and theupper jaw, as well as greater length of the lower jaw body, proportional to the length of the upper jaw body.

Lip line changes in Class III facial asymmetry patients after orthodontic camouflage treatment, one-jaw surgery, and two-jaw surgery: A preliminary study.

PubMed

Lee, Gung-Chol; Yoo, Jo-Kwang; Kim, Seong-Hun; Moon, Cheol-Hyun

2017-03-01

To evaluate the effects of orthodontic camouflage treatment (OCT), one-jaw surgery, and two-jaw surgery on the correction of lip line cant (LLC) and to examine factors affecting the correction of LLC in Class III craniofacial asymmetry patients. A sample of 30 Class III craniofacial asymmetry patients was divided into OCT (n = 10), one-jaw surgery (n = 10), and two-jaw surgery (n = 10) groups such that the pretreatment LLC was similar in each group. Pretreatment and posttreatment cone-beam computed tomography scans were used to measure dental and skeletal parameters and LLC. Pretreatment and posttreatment measurements were compared within groups and between groups. Pearson's correlation tests and multiple regression analyses were performed to investigate factors affecting the amount and rate of LLC correction. The average LLC correction was 1.00° in the one-jaw surgery group, and in the two-jaw surgery group, it was 1.71°. In the OCT group it was -0.04°, which differed statistically significantly from the LLC correction in the other two groups. The amount and rate of LLC correction could be explained by settling of skeletal discrepancies or LLC at pretreatment with goodness of fit percentages of approximately 82% and 41%, respectively. Orthognathic surgery resulted in significant correction of LLC in Class III craniofacial asymmetry patients, while OCT did not.

Effect of sympathetic nervous system activation on the tonic vibration reflex in rabbit jaw closing muscles.

PubMed

Grassi, C; Deriu, F; Passatore, M

1993-09-01

1. In precollicular decerebrate rabbits we investigated the effect of sympathetic stimulation, at frequencies within the physiological range, on the tonic vibration reflex (TVR) elicited in jaw closing muscles by small amplitude vibrations applied to the mandible (15-50 microns, 150-180 Hz). The EMG activity was recorded bilaterally from masseter muscle and the force developed by the reflex was measured through an isometric transducer connected with the mandibular symphysis. 2. Unilateral stimulation of the peripheral stump of the cervical sympathetic by the TVR, and a marked decrease or disappearance of the ipsilateral EMG activity. No significant changes were detected in the EMG contralateral to the stimulated nerve. Bilateral CSN stimulation reduced by 60-90% the force reflexly produced by the jaw closing muscles and strongly decreased or suppressed EMG activity on both sides. This effect was often preceded by a transient TVR enhancement, very variable in amplitude and duration, which was concomitant with the modest increase in pulmonary ventilation induced by the sympathetic stimulation. 3. During bilateral CSN stimulation, an increase in the vibration amplitude by a factor of 1.5-2.5 was sufficient to restore the TVR reduced by sympathetic stimulation. 4. The depressant action exerted by sympathetic activation on the TVR is mediated by alpha-adrenergic receptors, since it was almost completely abolished by the I.V. administration of either phentolamine or prazosin, this last drug being a selective antagonist of alpha 1-adrenoceptors. The sympathetically induced decrease in the TVR was not mimicked by manoeuvres producing a large and sudden reduction or abolition of the blood flow to jaw muscles, such as unilateral or bilateral occlusion of the common carotid artery. 5. The effect of sympathetic stimulation was not significantly modified after denervation of the inferior dental arch and/or anaesthesia of the temporomandibular joint, i.e. after having reduced

Range of motion exercise of temporo-mandibular joint with hot pack increases occlusal force in patients with Duchenne muscular dystrophy.

PubMed

Nozaki, S; Kawai, M; Shimoyama, R; Futamura, N; Matsumura, T; Adachi, K; Kikuchi, Y

2010-12-01

The purpose of this study is to evaluate whether the range of motion exercise of the temporo-mandibular joint (jaw ROM exercise) with a hot pack and massage of the masseter muscle improve biting disorder in Duchenne muscular dystrophy (DMD). The subjects were 18 DMD patients (21.3+/- 4.1 years old). The jaw ROM exercise consisted of therapist-assisted training (2 times a week) and self-training (before each meal every day). The therapist-assisted training consisted of the application of a hot pack on the cheek of the masseter muscle region (15 minutes), the massage of the masseter (10 minutes), and jaw ROM exercise (5 minutes). The self-training involved jaw ROM exercise by opening the mouth to the maximum degree, ten times. These trainings continued for six months. Outcomes were evaluated by measuring the greatest occlusal force and the distance at the maximum degree of mouth opening between an incisor of the top and that of the bottom. Six months later, the greatest occlusal force had increased significantly compared with that at the start of jaw ROM exercise (intermediate values: from 73.8N to 97.3N) (p = 0.005) as determined by the Friedman test and Scheffi's nonparametric test. The patients' satisfaction with meals increased. However, the maximum degree of mouth opening did not change after six months of jaw ROM exercise. Jaw ROM exercise in DMD is effective for increasing the greatest occlusal force.

Evidence for existence of trunk-limb neural interaction in the corticospinal pathway.

PubMed

Sasaki, Atsushi; Milosevic, Matija; Sekiguchi, Hirofumi; Nakazawa, Kimitaka

2018-03-06

In humans, trunk muscles have an essential role in postural control as well as walking. However, little is known about the mechanisms of interaction with different muscles, especially related to how trunk muscles interact with the limbs. Contraction of muscles can modulate the corticospinal excitability not only of the contracted muscle, but also of other muscles even in the remote segments of the body. However, "remote effect" mechanism has only been examined for inter-limb interactions. The aim of our current study was to test if there are trunk-limb interactions in the corticospinal pathways. We examined corticospinal excitability of: (a) trunk muscles at rest when hands, legs and jaw muscles were contracted and; (b) hand, leg, and jaw muscles at rest when trunk muscles were contracted. We measured motor evoked potentials elicited using transcranial magnetic stimulation in the rectus abdominis, flexor digitorum superficialis, masseter, tibialis anterior muscles under the following experimental conditions: (1) participants remained relaxed (Rest); (2) during trunk contraction (Trunk); (3) during bilateral hand clenching (Hands); (4) during jaw clenching (Jaw); and (5) during bilateral ankle dorsiflexion (Legs). Each condition was performed at three different stimulation intensities and conditions were randomized between participants. We found that voluntary contraction of trunk muscle facilitated the corticospinal excitability of upper-limb and lower-limb muscles during rest state. Furthermore, voluntary contraction of upper-limb muscle also facilitated the corticospinal excitability of trunk muscles during rest state. Overall, these results suggest the existence of trunk-limb interaction in the corticospinal pathway, which is likely depended on proximity of the trunk and limb representation in the motor cortex. Copyright © 2018 Elsevier B.V. All rights reserved.

Proximate determinants of bite force in Anolis lizards.

PubMed

Wittorski, Antoine; Losos, Jonathan B; Herrel, Anthony

2016-01-01

Performance measures associated with the vertebrate jaw system may provide important insights into vertebrate ecology and evolution because of their importance in many ecologically relevant tasks. Previous studies have shown that in many taxa, evolution toward higher bite force has gone hand in hand with the evolution of larger body size. However, independent of differences in overall body size, bite force may vary depending on head size and shape as well. Moreover, the underlying musculature may also drive variation in bite force. Here, we investigate the proximate determinants of bite force in lizards of the genus Anolis. We dissected the jaw muscles and quantified muscle mass, fibre length, and cross-sectional area. Data were analysed for both sexes independently given the sexual dimorphism detected in the dataset. Our results show that the traits that explain bite force are similar in both males and females with overall body size and muscle mass being the principal determinants. Among the different muscles examined, the adductor externus and the pseudotemporalis groups were the best determinants of bite force. However, models run for males predicted the variation in bite force better than models for females, suggesting that selection on morphology improving bite force may be stronger in males. © 2015 Anatomical Society.

Effect of hypnosis on masseter EMG recorded during the 'resting' and a slightly open jaw posture.

PubMed

Al-Enaizan, N; Davey, K J; Lyons, M F; Cadden, S W

2015-11-01

The aim of this experimental study was to determine whether minimal levels of electromyographic activity in the masseter muscle are altered when individuals are in a verified hypnotic state. Experiments were performed on 17 volunteer subjects (8 male, 9 female) all of whom gave informed consent. The subjects were dentate and had no symptoms of pain or masticatory dysfunction. Surface electromyograms (EMGs) were made from the masseter muscles and quantified by integration following full-wave rectification and averaging. The EMGs were obtained (i) with the mandible in 'resting' posture; (ii) with the mandible voluntarily lowered (but with the lips closed); (iii) during maximum voluntary clenching (MVC). The first two recordings were made before, during and after the subjects were in a hypnotic state. Susceptibility to hypnosis was assessed with Spiegel's eye-roll test, and the existence of the hypnotic state was verified by changes in ventilatory pattern. On average, EMG levels expressed as percentages of MVC were less: (i) when the jaw was deliberately lowered as opposed to being in the postural position: (ii) during hypnosis compared with during the pre- and post-hypnotic periods. However, analysis of variance followed by post hoc tests with multiple comparison corrections (Bonferroni) revealed that only the differences between the level during hypnosis and those before and after hypnosis were statistically significant (P < 0·05). As the level of masseter EMG when the mandible was in 'resting' posture was reduced by hypnosis, it appears that part of that EMG is of biological origin. © 2015 John Wiley & Sons Ltd.

SU-F-E-19: A Novel Method for TrueBeam Jaw Calibration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Corns, R; Zhao, Y; Huang, V

2016-06-15

Purpose: A simple jaw calibration method is proposed for Varian TrueBeam using an EPID-Encoder combination that gives accurate fields sizes and a homogeneous junction dose. This benefits clinical applications such as mono-isocentric half-beam block breast cancer or head and neck cancer treatment with junction/field matching. Methods: We use EPID imager with pixel size 0.392 mm × 0.392 mm to determine the radiation jaw position as measured from radio-opaque markers aligned with the crosshair. We acquire two images with different symmetric field sizes and record each individual jaw encoder values. A linear relationship between each jaw’s position and its encoder valuemore » is established, from which we predict the encoder values that produce the jaw positions required by TrueBeam’s calibration procedure. During TrueBeam’s jaw calibration procedure, we move the jaw with the pendant to set the jaw into position using the predicted encoder value. The overall accuracy is under 0.1 mm. Results: Our in-house software analyses images and provides sub-pixel accuracy to determine field centre and radiation edges (50% dose of the profile). We verified the TrueBeam encoder provides a reliable linear relationship for each individual jaw position (R{sup 2}>0.9999) from which the encoder values necessary to set jaw calibration points (1 cm and 19 cm) are predicted. Junction matching dose inhomogeneities were improved from >±20% to <±6% using this new calibration protocol. However, one technical challenge exists for junction matching, if the collimator walkout is large. Conclusion: Our new TrueBeam jaw calibration method can systematically calibrate the jaws to crosshair within sub-pixel accuracy and provides both good junction doses and field sizes. This method does not compensate for a larger collimator walkout, but can be used as the underlying foundation for addressing the walkout issue.« less

Pediatric jaw fractures: indications for open reduction.

PubMed

Krausen, A S; Samuel, M

1979-01-01

Jaw fractures in children are generally managed without major surgical intervention. Closed reduction usually is sufficient to restore normal anatomy and function. The one inviolate principle is early treatment. During the past three years, four pediatric jaw fractures that required open reduction were treated. This mode of treatment was necessitated by the limitations imposed by pediatric dental anatomy and by the type of fractures encountered. In at least 24 months of follow-up, no dental problems have been seen.

Does induced masseter muscle pain affect integrated jaw-neck movements similarly in men and women?

PubMed

Wiesinger, Birgitta; Häggman-Henrikson, Birgitta; Hellström, Fredrik; Englund, Erling; Wänman, Anders

2016-12-01

Normal jaw opening-closing involves simultaneous jaw and head-neck movements. We previously showed that, in men, integrated jaw-neck movements during jaw function are altered by induced masseter muscle pain. The aim of this study was to investigate possible sex-related differences in integrated jaw-neck movements following experimental masseter muscle pain. We evaluated head-neck and jaw movements in 22 healthy women and 16 healthy men in a jaw opening-closing task. The participants performed one control trial and one trial with masseter muscle pain induced by injection of hypertonic saline. Jaw and head movements were registered using a three-dimensional optoelectronic recording system. There were no significant sex-related differences in jaw and head movement amplitudes. Head movement amplitudes were significantly greater in the pain trials for both men and women. The proportional involvement of the neck motor system during jaw movements increased in pain trials for 13 of 16 men and for 18 of 22 women. Thus, acute pain may alter integrated jaw-neck movements, although, given the similarities between men and women, this interaction between acute pain and motor behaviour does not explain sex differences in musculoskeletal pain in the jaw and neck regions. © 2016 Eur J Oral Sci.

Three-dimensional finite element analysis of the deformation of the human mandible: a preliminary study from the perspective of orthodontic mini-implant stability

PubMed Central

Baek, Sun-Hye; Cha, Hyun-Suk; Cha, Jung-Yul; Moon, Yoon-Shik

2012-01-01

Objective The aims of this study were to investigate mandibular deformation under clenching and to estimate its effect on the stability of orthodontic mini-implants (OMI). Methods Three finite element models were constructed using computed tomography (CT) images of 3 adults with different mandibular plane angles (A, low; B, average; and C, high). An OMI was placed between #45 and #46 in each model. Mandibular deformation under premolar and molar clenching was simulated. Comparisons were made between peri-orthodontic mini-implant compressive strain (POMI-CSTN) under clenching and orthodontic traction forces (150 g and 200 g). Results Three models with different mandibular plane angles demonstrated different functional deformation characteristics. The compressive strains around the OMI were distributed mesiodistally rather than occlusogingivally. In model A, the maximum POMI-CSTN under clenching was observed at the mesial aspect of #46 (1,401.75 microstrain [µE]), and similar maximum POMI-CSTN was observed under a traction force of 150 g (1,415 µE). Conclusions The maximum POMI-CSTN developed by clenching failed to exceed the normally allowed compressive cortical bone strains; however, additional orthodontic traction force to the OMI may increase POMI-CSTN to compromise OMI stability. PMID:23112947

Spectral characteristics of speech with fixed jaw displacements

NASA Astrophysics Data System (ADS)

Solomon, Nancy P.; Makashay, Matthew J.; Munson, Benjamin

2004-05-01

During speech, movements of the mandible and the tongue are interdependent. For some research purposes, the mandible may be constrained to ensure independent tongue motion. To examine specific spectral characteristics of speech with different jaw positions, ten normal adults produced sentences with multiple instances of /t/, /s/, /squflg/, /i/, /ai/, and /squflgi/. Talkers produced stimuli with the jaw free to vary, and while gently biting on 2- and 5-mm bite blocks unilaterally. Spectral moments of /s/ and /squflg/ frication and /t/ bursts differed such that mean spectral energy decreased, and diffuseness and skewness increased with bite blocks. The specific size of the bite block had minimal effect on these results, which were most consistent for /s/. Formant analysis for the vocoids revealed lower F2 frequency in /i/ and at the end of the transition in /ai/ when bite blocks were used; F2 slope for diphthongs was not sensitive to differences in jaw position. Two potential explanations for these results involve the physical presence of the bite blocks in the lateral oral cavity, and the oromotor system's ability to compensate for fixed jaw displacements. [Work supported by NIDCD R03-DC06096.

An Ancient Gene Network Is Co-opted for Teeth on Old and New Jaws

PubMed Central

Fraser, Gareth J; Hulsey, C. Darrin; Bloomquist, Ryan F; Uyesugi, Kristine; Manley, Nancy R; Streelman, J. Todd

2009-01-01

Vertebrate dentitions originated in the posterior pharynx of jawless fishes more than half a billion years ago. As gnathostomes (jawed vertebrates) evolved, teeth developed on oral jaws and helped to establish the dominance of this lineage on land and in the sea. The advent of oral jaws was facilitated, in part, by absence of hox gene expression in the first, most anterior, pharyngeal arch. Much later in evolutionary time, teleost fishes evolved a novel toothed jaw in the pharynx, the location of the first vertebrate teeth. To examine the evolutionary modularity of dentitions, we asked whether oral and pharyngeal teeth develop using common or independent gene regulatory pathways. First, we showed that tooth number is correlated on oral and pharyngeal jaws across species of cichlid fishes from Lake Malawi (East Africa), suggestive of common regulatory mechanisms for tooth initiation. Surprisingly, we found that cichlid pharyngeal dentitions develop in a region of dense hox gene expression. Thus, regulation of tooth number is conserved, despite distinct developmental environments of oral and pharyngeal jaws; pharyngeal jaws occupy hox-positive, endodermal sites, and oral jaws develop in hox-negative regions with ectodermal cell contributions. Next, we studied the expression of a dental gene network for tooth initiation, most genes of which are similarly deployed across the two disparate jaw sites. This collection of genes includes members of the ectodysplasin pathway, eda and edar, expressed identically during the patterning of oral and pharyngeal teeth. Taken together, these data suggest that pharyngeal teeth of jawless vertebrates utilized an ancient gene network before the origin of oral jaws, oral teeth, and ectodermal appendages. The first vertebrate dentition likely appeared in a hox-positive, endodermal environment and expressed a genetic program including ectodysplasin pathway genes. This ancient regulatory circuit was co-opted and modified for teeth in oral

Synovial sarcoma of the jaw in a dog.

PubMed

Griffith, J W; Frey, R A; Sharkey, F E

1987-05-01

A case of synovial sarcoma of the jaw with pulmonary metastasis is described in a dog. It appears to be a rare or underdiagnosed neoplasm in animals and not previously reported in the jaw. Its diagnostic microscopic features are the biphasic cellular pattern and cleft formations. It may otherwise resemble haemangiopericytoma, malignant fibrous histiocytoma, reticulum cell sarcoma, fibrosarcoma, or giant-cell tumour of soft tissue.

The characters of Palaeozoic jawed vertebrates

PubMed Central

Brazeau, Martin D; Friedman, Matt

2014-01-01

Newly discovered fossils from the Silurian and Devonian periods are beginning to challenge embedded perceptions about the origin and early diversification of jawed vertebrates (gnathostomes). Nevertheless, an explicit cladistic framework for the relationships of these fossils relative to the principal crown lineages of the jawed vertebrates (osteichthyans: bony fishes and tetrapods; chondrichthyans: sharks, batoids, and chimaeras) remains elusive. We critically review the systematics and character distributions of early gnathostomes and provide a clearly stated hierarchy of synapomorphies covering the jaw-bearing stem gnathostomes and osteichthyan and chondrichthyan stem groups. We show that character lists, designed to support the monophyly of putative groups, tend to overstate their strength and lack cladistic corroboration. By contrast, synapomorphic hierarchies are more open to refutation and must explicitly confront conflicting evidence. Our proposed synapomorphy scheme is used to evaluate the status of the problematic fossil groups Acanthodii and Placodermi, and suggest profitable avenues for future research. We interpret placoderms as a paraphyletic array of stem-group gnathostomes, and suggest what we regard as two equally plausible placements of acanthodians: exclusively on the chondrichthyan stem, or distributed on both the chondrichthyan and osteichthyan stems. PMID:25750460

Mechanics of snout expansion in suction-feeding seahorses: musculoskeletal force transmission.

PubMed

Van Wassenbergh, Sam; Leysen, Heleen; Adriaens, Dominique; Aerts, Peter

2013-02-01

Seahorses and other syngnathid fishes rely on a widening of the snout to create the buccal volume increase needed to suck prey into the mouth. This snout widening is caused by abduction of the suspensoria, the long and flat bones outlining the lateral sides of the mouth cavity. However, it remains unknown how seahorses can generate a forceful abduction of the suspensoria. To understand how force is transmitted to the suspensoria via the hyoid and the lower jaw, we performed mathematical simulations with models based on computerized tomography scans of Hippocampus reidi. Our results show that the hinge joint between the left and right hyoid bars, as observed in H. reidi, allows for an efficient force transmission to the suspensorium from a wide range of hyoid angles, including the extremely retracted hyoid orientations observed in vivo for syngnathids. Apart from the hyoid retraction force by the sternohyoideus-hypaxial muscles, force generated in the opposite direction on the hyoid by the mandibulohyoid ligament also has an important contribution to suspensorium abduction torque. Forces on the lower jaw contribute only approximately 10% of the total suspensorium torque. In particular, when dynamical aspects of hyoid retraction are included in the model, a steep increase is shown in suspensorium abduction torque at highly retracted hyoid positions, when the linkages to the lower jaw counteract further hyoid rotation in the sagittal plane. A delayed strain in these linkages allows syngnathids to postpone suction generation until the end of cranial rotation, a fundamental difference from non-syngnathiform fishes.

Surgical treatment of jaw osteonecrosis in "Krokodil" drug addicted patients.

PubMed

Poghosyan, Yuri M; Hakobyan, Koryun A; Poghosyan, Anna Yu; Avetisyan, Eduard K

2014-12-01

Retrospective study of jaw osteonecrosis treatment in patients using the "Krokodil" drug from 2009 to 2013. On the territory of the former USSR countries there is widespread use of a self-produced drug called "Krokodil". Codeine containing analgesics ("Sedalgin", "Pentalgin" etc), red phosphorus (from match boxes) and other easily acquired chemical components are used for synthesis of this drug, which used intravenously. Jaw osteonecrosis develops as a complication in patients who use "Krokodil". The main feature of this disease is jawbone exposure in the oral cavity. Surgery is the main method for the treatment of jaw osteonecrosis in patients using "Krokodil". 40 "Krokodil" drug addict patients with jaw osteonecrosis were treated. Involvement of maxilla was found in 11 patients (27.5%), mandible in 21 (52.5%), both jaws in 8 (20%) patients. 35 Lesions were found in 29 mandibles and 21 lesions in 19 maxillas. Main factors of treatment success are: cessation of "Krokodil" use in the pre- (minimum 1 month) and postoperative period and osteonecrosis area resection of a minimum of 0.5 cm beyond the visible borders of osteonecrosis towards the healthy tissues. Surgery was not delayed until sequestrum formation. In the mandible marginal or segmental resection (with or without TMJ exarticulation) was performed. After surgery recurrence of disease was seen in 8 (23%) cases in the mandible, with no cases of recurrence in the maxilla. According to our experience in this case series, surgery is the main method for the treatment of jaw osteonecrosis in patients using "Krokodil". Cessation of drug use and jaw resection minimize the rate of recurrences in such patients. Copyright © 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Pain and Disability in the Jaw and Neck Region following Whiplash Trauma.

PubMed

Häggman-Henrikson, B; Lampa, E; Marklund, S; Wänman, A

2016-09-01

The relationship between whiplash trauma and chronic orofacial pain is unclear, especially with regard to the time elapsed from trauma to development of orofacial pain. The aim was to analyze prevalence of jaw pain and disability, as well as the relationship between pain and disability in the jaw and neck regions in the early nonchronic stage after whiplash trauma. In this case-control study, 70 individuals (40 women, 30 men, mean age 35.5 y) who visited an emergency department with neck pain following a car accident were examined within 3 wk of trauma (group 1) and compared with 70 individuals (42 women, 28 men, mean age 33.8 y), who declined to attend a clinical examination but agreed to fill in questionnaires (group 2). The 2 case groups were compared with a matched control group of 70 individuals (42 women, 28 men, mean age 37.6 y) without a history of neck trauma. All participants completed questionnaires regarding jaw pain and dysfunction, rating pain intensity in jaw and neck regions on the Numerical Rating Scale, the Neck Disability Index, and Jaw Disability Checklist. Compared with controls, individuals with a recent whiplash trauma reported more jaw pain and dysfunction. Furthermore, there was a moderate positive correlation between jaw and neck pain ratings for group 1 (r = 0.61, P < 0.0001) and group 2 (r = 0.59, P < 0.0001). In the logistic regression analysis, cases showed higher odds ratios (range, 6.1 to 40.8) for jaw and neck pain and disability compared with controls. Taken together, the results show that individuals with a recent whiplash trauma report more jaw pain and disability compared with controls without a history of neck trauma. Furthermore, the correlation between jaw and neck pain intensity implies that intensity of neck pain in the acute stage after whiplash trauma might be a possible risk factor also for development of chronic orofacial pain. © International & American Associations for Dental Research 2016.

Jaw1/LRMP has a role in maintaining nuclear shape via interaction with SUN proteins.

PubMed

Kozono, Takuma; Tadahira, Kazuko; Okumura, Wataru; Itai, Nao; Tamura-Nakano, Miwa; Dohi, Taeko; Tonozuka, Takashi; Nishikawa, Atsushi

2018-06-06

Jaw1/LRMP is characterized as a type II integral membrane protein that is localized to endoplasmic reticulum (ER), however, its physiological functions have been poorly understood. An alignment of amino acid sequence of Jaw1 with KASH proteins, outer nuclear membrane proteins, revealed that Jaw1 has a partial homology to the KASH domain. Here, we show that the function of Jaw1 is to maintain nuclear shape in mouse melanoma cell line. The siRNA-mediated knockdown of Jaw1 caused a severe defect in nuclear shape, and the defect was rescued by ectopic expression of siRNA-resistant Jaw1. Since co-immunoprecipitation assay indicates that Jaw1 interacts with SUN proteins that are inner nuclear proteins and microtubules, this study suggests that Jaw1 has a role in maintaining nuclear shape via interactions with SUN proteins and microtubules.

Pilot-Vehicle Interface

DTIC Science & Technology

2000-03-01

consent response, a " Midas touch " date, subtle/slight eyebrow lifts and jaw clenches problem could occur, with commands activating have been...from the display. For flights where the outside scene is visible, it Problems such as this can result in misjudgments of remains to be determined...without degrading the probability of kill [28]. display. The subjects commented that the key problem was the ambiguity in depth judgement along Any

Digital impression and jaw relation record for the fabrication of CAD/CAM custom tray.

PubMed

Kanazawa, Manabu; Iwaki, Maiko; Arakida, Toshio; Minakuchi, Shunsuke

2018-03-16

This article describes the protocol of a digital impression technique to make an impression and recording of the jaw relationship of edentulous patients for the fabrication of CAD/CAM custom tray using computer-aided design and manufacturing (CAD/CAM) technology. Scan the maxillary and mandibular edentulous jaws using an intraoral scanner. Scan the silicone jig with the maxillary and mandibular jaws while keeping the jig between the jaws. Import the standard tessellation language data of the maxillary and mandibular jaws and jig to make a jaw relation record and fabricate custom trays (CAD/CAM trays) using a rapid prototyping system. Make a definitive impression of the maxillary and mandibular jaws using the CAD/CAM trays. Digitalization of the complete denture fabrication process can simplify the complicated treatment and laboratory process of conventional methods In addition, the proposed method enables quality control regardless of the operator's experience and technique. Copyright © 2018. Published by Elsevier Ltd.

Masticatory jaw movement of Exaeretodon argentinus (Therapsida: Cynodontia) inferred from its dental microwear

PubMed Central

Yamada, Eisuke; Kubo, Mugino O.

2017-01-01

Dental microwear of four postcanine teeth of Exaeretodon argentinus was analyzed using both two dimensional (2D) and three dimensional (3D) methods to infer their masticatory jaw movements. Results of both methods were congruent, showing that linear microwear features (scratches) were well aligned and mostly directed to the antero-posterior direction in all four teeth examined. These findings support the palinal masticatory jaw movement, which was inferred in previous studies based on the observation of gross morphology of wear facets. In contrast, the lack of detection of lateral scratches confirmed the absence of the lateral jaw movement that was also proposed by a previous study. Considering previous microwear studies on cynodonts, palinal jaw movements observed in Exaeretodon evolved within cynognathian cynodonts from the fully orthal jaw movement of its basal member. Although there are currently only three studies of dental microwear of non-mammalian cynodonts including the present study, microwear analysis is a useful tool for the reconstruction of masticatory jaw movement and its future application to various cynodonts will shed light on the evolutionary process of jaw movement towards the mammalian condition in more detail. PMID:29186178

Kinematic analysis of jaw function in children following traumatic brain injury.

PubMed

Loh, E W L; Goozée, J V; Murdoch, B E

2005-07-01

To investigate jaw movements in children following traumatic brain injury (TBI) during speech using electromagnetic articulography (EMA). Jaw movements of two non-dysarthric children (aged 12.75 and 13.08 years) who had sustained a TBI were recorded using the AG-100 EMA system (Carstens Medizineletronik) during word-initial consonant productions. Mean quantitative kinematic parameters and coefficient of variation (variability) values were calculated and individually compared to the mean values obtained by a group of six control children (mean age 12.57 years, SD 1.52). The two children with TBI exhibited word-initial consonant jaw movement durations that were comparable to the control children, with sub-clinical reductions in speed being offset by reduced distances. Differences were observed between the two children in jaw kinematic variability, with one child exhibiting increased variability, while the other child demonstrated reduced or comparable variability compared to the control group. Possible sub-clinical impairments of jaw movement for speech were exhibited by two children who had sustained a TBI, providing insight into the consequences of TBI on speech motor control development.

Developmental evidence for serial homology of the vertebrate jaw and gill arch skeleton

PubMed Central

Gillis, J. Andrew; Modrell, Melinda S.; Baker, Clare V. H.

2013-01-01

Gegenbaur’s classical hypothesis of jaw-gill arch serial homology is widely cited, but remains unsupported by either paleontological evidence (e.g. a series of fossils reflecting the stepwise transformation of a gill arch into a jaw) or developmental genetic data (e.g. shared molecular mechanisms underlying segment identity in the mandibular, hyoid and gill arch endoskeletons). Here we show that nested expression of Dlx genes – the “Dlx code” that specifies upper and lower jaw identity in mammals and teleosts – is a primitive feature of the mandibular, hyoid and gill arches of jawed vertebrates. Using fate-mapping techniques, we demonstrate that the principal dorsal and ventral endoskeletal segments of the jaw, hyoid and gill arches of the skate Leucoraja erinacea derive from molecularly equivalent mesenchymal domains of combinatorial Dlx gene expression. Our data suggest that vertebrate jaw, hyoid and gill arch cartilages are serially homologous, and were primitively patterned dorsoventrally by a common Dlx blueprint. PMID:23385581

Two-year follow-up of changes in bite force and occlusal contact area after intraoral vertical ramus osteotomy with and without Le Fort I osteotomy.

PubMed

Choi, Y J; Lim, H; Chung, C J; Park, K H; Kim, K H

2014-06-01

This study was performed to examine the longitudinal changes in bite force and occlusal contact area after mandibular setback surgery via intraoral vertical ramus osteotomy (IVRO). Patients with mandibular prognathism who underwent IVRO (surgical group: 39 men and 39 women) were compared with subjects with class I skeletal and dental relationships (control group; 32 men and 35 women). The surgical group was divided into two subgroups: 1-jaw surgery (n = 30) and 2-jaw surgery (n = 48). Bite force and contact area were measured in maximum intercuspation with the Dental Prescale System before treatment, within 1 month before surgery, and at 1, 3, 6, 9, 12, and 24 months postsurgery. A linear mixed model was used to investigate the time-dependent changes and associated factors. Bite force and contact area decreased during presurgical orthodontic treatment, were minimal at 1 month postsurgery, and increased gradually thereafter. The 1-jaw and 2-jaw subgroups showed no significant differences in bite force. The time-dependent changes in bite force were significantly different according to the contact area (P < 0.05). The results of this study suggest that bite force and occlusal contact area gradually increase throughout the postsurgical evaluation period. Increasing the occlusal contact area may be essential for improving bite force after surgery. Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

A novel laparoscopic grasper with two parallel jaws capable of extracting the mechanical behaviour of soft tissues.

PubMed

Nazarynasab, Dariush; Farahmand, Farzam; Mirbagheri, Alireza; Afshari, Elnaz

2017-07-01

Data related to force-deformation behaviour of soft tissue plays an important role in medical/surgical applications such as realistically modelling mechanical behaviour of soft tissue as well as minimally invasive surgery (MIS) and medical diagnosis. While the mechanical behaviour of soft tissue is very complex due to its different constitutive components, some issues increase its complexity like behavioural changes between the live and dead tissues. Indeed, an adequate quantitative description of mechanical behaviour of soft tissues requires high quality in vivo experimental data to be obtained and analysed. This paper describes a novel laparoscopic grasper with two parallel jaws capable of obtaining compressive force-deformation data related to mechanical behaviour of soft tissues. This new laparoscopic grasper includes four sections as mechanical hardware, sensory part, electrical/electronical part and data storage part. By considering a unique design for mechanical hardware, data recording conditions will be close to unconfined-compression-test conditions; so obtained data can be properly used in extracting the mechanical behaviour of soft tissues. Also, the other distinguishing feature of this new system is its applicability during different laparoscopic surgeries and subsequently obtaining in vivo data. However, more preclinical examinations are needed to evaluate the practicality of the novel laparoscopic grasper with two parallel jaws.

[Odontogenic and nonodontogenic jaw cysts: experience in 25 cases].

PubMed

Ağir, Hakan; Sen, Cenk; Işil, Eda; Unal, Ciğdem; Ustündağ, Emre; Keskin, Gürkan

2008-01-01

We retrospectively evaluated the patients with jaw cysts treated at our center. The study included 25 patients (14 males, 11 females; mean age 33+/-19 years; range 7 to 69 years) who underwent surgery for odontogenic or nonodontogenic jaw cysts. The most common presentation was a swelling in the jaw with or without dental problems. Involvement was in the mandible in 18 patients, and in the maxilla in seven patients. The lesions consisted of eight radicular, six dentigerous, two nasoalveolar, two globulomaxillary cysts, and three keratocysts. Four patients had gingival, nasopalatine, residual, and median mandibular cysts, respectively. Marsupialization, curettage, extensive burring, enucleation, or marginal resection were performed depending on pre- and intraoperative findings. The defects were repaired with a corticocancellous iliac bone block graft in three patients and cancellous iliac bone chips in five patients. During a mean follow-up of 14 months (range 12 to 46 months), recurrence was seen in only one patient with a keratocyst. A good preoperative assessment, complete removal of the cystic lesion, and close radiographic follow-up are essential for a successful outcome in jaw cysts. In selected cases, reconstruction of the defects with autogenous corticocancellous iliac bone graft yields highly satisfactory results.

The speech focus position effect on jaw-finger coordination in a pointing task.

PubMed

Rochet-Capellan, Amélie; Laboissière, Rafael; Galván, Arturo; Schwartz, Jean-Luc

2008-12-01

This article investigates jaw-finger coordination in a task involving pointing to a target while naming it with a CVCV (e.g., /papa/) versus CVCV (e.g., /papa/) word. According to the authors' working hypothesis, the pointing apex (gesture extremum) would be synchronized with the apex of the jaw-opening gesture corresponding to the stressed syllable. Jaw and finger motions were recorded using Optotrak (Northern Digital, Waterloo, Ontario, Canada). The effects of stress position on jaw-finger coordination were tested across different target positions (near vs. far) and different consonants in the target word (/t/ vs. /p/). Twenty native Portuguese Brazilian speakers participated in the experiment (all conditions). Jaw response starts earlier, and finger-target alignment period is longer for CVCV words than for CVCV ones. The apex of the jaw-opening gesture for the stressed syllable appears synchronized with the onset of the finger-target alignment period (corresponding to the pointing apex) for CVCV words and with the offset of that period for CVCV words. For both stress conditions, the stressed syllable occurs within the finger-target alignment period because of tight finger-jaw coordination. This result is interpreted as evidence for an anchoring of the speech deictic site (part of speech that shows) in the pointing gesture.

Electronic speckle-pattern interferometry (ESPI) applied to the study of mechanical behavior of human jaws

NASA Astrophysics Data System (ADS)

Roman, Juan F.; Moreno de las Cuevas, Vincente; Salgueiro, Jose R.; Suarez, David; Fernandez, Paula; Gallas, Mercedes; Blanchard, Alain

1996-01-01

The study of the mechanical behavior of the human jaw during chewing is helpful in several specific medical fields that cover the maxillo-facial area. In this work, electronic speckle pattern interferometry has been applied to study dead jaw bones under external stress which simulates the deformations induced during chewing. Fringes obtained after subtraction of two images of the jaw, the image of the relaxed jaw and that of the jaw under stress, give us information about the most stressed zones. The interferometric analysis proposed here is attractive as it can be done in real time with the jaw under progressive stress. Image processing can be applied for improving the quality of fringes. This research can be of help in orthognathic surgery, for example in diagnosis and treatment of fractured jaws, in oral surgery, and in orthodontics because it would help us to know the stress dispersion when we insert an osseointegrated implant or place an orthodontic appliance, respectively. Studying fragments of human jaw some results about its elasticity and flexibility were obtained.

Building Finite Element Models to Investigate Zebrafish Jaw Biomechanics.

PubMed

Brunt, Lucy H; Roddy, Karen A; Rayfield, Emily J; Hammond, Chrissy L

2016-12-03

Skeletal morphogenesis occurs through tightly regulated cell behaviors during development; many cell types alter their behavior in response to mechanical strain. Skeletal joints are subjected to dynamic mechanical loading. Finite element analysis (FEA) is a computational method, frequently used in engineering that can predict how a material or structure will respond to mechanical input. By dividing a whole system (in this case the zebrafish jaw skeleton) into a mesh of smaller 'finite elements', FEA can be used to calculate the mechanical response of the structure to external loads. The results can be visualized in many ways including as a 'heat map' showing the position of maximum and minimum principal strains (a positive principal strain indicates tension while a negative indicates compression. The maximum and minimum refer the largest and smallest strain). These can be used to identify which regions of the jaw and therefore which cells are likely to be under particularly high tensional or compressional loads during jaw movement and can therefore be used to identify relationships between mechanical strain and cell behavior. This protocol describes the steps to generate Finite Element models from confocal image data on the musculoskeletal system, using the zebrafish lower jaw as a practical example. The protocol leads the reader through a series of steps: 1) staining of the musculoskeletal components, 2) imaging the musculoskeletal components, 3) building a 3 dimensional (3D) surface, 4) generating a mesh of Finite Elements, 5) solving the FEA and finally 6) validating the results by comparison to real displacements seen in movements of the fish jaw.

[Osteonecrosis of the jaws and bisphosphonates].

PubMed

Junod, A F; Carrel, J-P; Richter, M; Vogt-Ferrier, N

2005-11-02

Widely prescribed, bisphosphonates inhibit bone resorption. They are not metabolised and have long half-lives. Two cases of osteonecrosis of the jaws have recently been attributed to bisphosphonates at the University Hospital of Geneva. The recent literature reveals more than a hundred similar cases throughout the world. Bone exposure appears spontaneously or after dental care. Treatment of the osteonecrosis is controversial and cure very difficult. This pathology is usually seen in patients on chemotherapy, steroids and i.v. bisphosphonates, but is sometimes seen with low-dose p.o. bisphosphonates. In view of the strong association between bisphosphonate therapy and osteonecrosis of the jaw, specialists have recommended dental and oral evaluation during bisphosphonate therapy as well as for several years after drug discontinuation.

Physiologic Development of Tongue-Jaw Coordination from Childhood to Adulthood

ERIC Educational Resources Information Center

Cheng, Hei Yan; Murdoch, Bruce E.; Goozee, Justine V.; Scott, Dion

2007-01-01

Purpose: This investigation aimed to examine the development of tongue-jaw coordination during speech from childhood to adolescence. Method: Electromagnetic articulography was used to track tongue and jaw motion in 48 children and adults (aged 6-38 years) during productions of /t/ and /k/ embedded in sentences. Results: The coordinative…

Comparative jaw muscle anatomy in kangaroos, wallabies, and rat-kangaroos (marsupialia: macropodoidea).

PubMed

Warburton, Natalie Marina

2009-06-01

The jaw muscles were studied in seven genera of macropodoid marsupials with diets ranging from mainly fungi in Potorous to grass in Macropus. Relative size, attachments, and lamination within the jaw adductor muscles varied between macropodoid species. Among macropodine species, the jaw adductor muscle proportions vary with feeding type. The relative mass of the masseter is roughly consistent, but grazers and mixed-feeders (Macropus and Lagostrophus) had relatively larger medial pterygoids and smaller temporalis muscles than the browsers (Dendrolagus, Dorcopsulus, and Setonix). Grazing macropods show similar jaw muscle proportions to "ungulate-grinding" type placental mammals. The internal architecture of the jaw muscles also varies between grazing and browsing macropods, most significantly, the anatomy of the medial pterygoid muscle. Potoroines have distinctly different jaw muscle proportions to macropodines. The masseter muscle group, in particular, the superficial masseter is enlarged, while the temporalis group is relatively reduced. Lagostrophus fasciatus is anatomically distinct from other macropods with respect to its masticatory muscle anatomy, including enlarged superficial medial pterygoid and deep temporalis muscles, an anteriorly inflected masseteric process, and the shape of the mandibular condyle. The enlarged triangular pterygoid process of the sphenoid bone, in particular, is distinctive of Lagsotrophus. (c) 2009 Wiley-Liss, Inc.

Jaw-opening reflex and corticobulbar motor excitability changes during quiet sleep in non-human primates.

PubMed

Yao, Dongyuan; Lavigne, Gilles J; Lee, Jye-Chang; Adachi, Kazunori; Sessle, Barry J

2013-02-01

To test the hypothesis that the reflex and corticobulbar motor excitability of jaw muscles is reduced during sleep. Polysomnographic recordings in the electrophysiological study. University sleep research laboratories. The reflex and corticobulbar motor excitability of jaw muscles was determined during the quiet awake state (QW) and quiet sleep (QS) in monkeys (n = 4). During QS sleep, compared to QW periods, both tongue stimulation-evoked jaw-opening reflex peak and root mean square amplitudes were significantly decreased with stimulations at 2-3.5 × thresholds (P < 0.001). The jaw-opening reflex latency during sleep was also significantly longer than during QW. Intracortical microstimulation (ICMS) within the cortical masticatory area induced rhythmic jaw movements at a stable threshold (≤ 60 μA) during QW; but during QS, ICMS failed to induce any rhythmic jaw movements at the maximum ICMS intensity used, although sustained jaw-opening movements were evoked at significantly increased threshold (P < 0.001) in one of the monkeys. Similarly, during QW, ICMS within face primary motor cortex induced orofacial twitches at a stable threshold (≤ 35 μA), but the ICMS thresholds were elevated during QS. Soon after the animal awoke, rhythmic jaw movements and orofacial twitches could be evoked at thresholds similar to those before QS. The results suggest that the excitability of reflex and corticobulbar-evoked activity in the jaw motor system is depressed during QS.

Description of the lower jaws of Baculites from the Upper Cretaceous U.S. Western Interior

NASA Astrophysics Data System (ADS)

Larson, Neal L.; Landman, Neil H.

2017-03-01

We report the discovery of lower jaws of Baculites (Ammonoidea) from the Upper Cretaceous U.S. Western Interior. In the lower Campanian Smoky Hill Chalk Member of the Niobrara Chalk of Kansas, most of the jaws occur as isolated elements. Based on their age, they probably belong to Baculites sp. (smooth). They conform to the description of rugaptychus, and are ornamented with coarse rugae on their ventral side. One specimen is preserved inside a small fecal pellet that was probably produced by a fish. Another specimen occurs inside in a crushed body chamber near the aperture and is probably in situ. Three small structures are present immediately behind the jaw and may represent the remains of the gills. In the lower Maastrichtian Pierre Shale of Wyoming, two specimens of Baculites grandis contain lower jaws inside their body chambers, and are probably in situ. In both specimens, the jaws are oriented at an acute angle to the long axis of the shell, with their anterior ends pointing toward the dorsum. One of the jaws is folded into a U-shape, which probably approximates the shape of the jaw during life. Based on the measurements of the jaws and the shape of the shell, the jaws could not have touched the sides of the shell even if they were splayed out, implying that they could not have effectively served as opercula. Instead, in combination with the upper jaws and radula, they constituted the buccal apparatus that collected and conveyed food to the esophagus.

An examination of the degrees of freedom of human jaw motion in speech and mastication.

PubMed

Ostry, D J; Vatikiotis-Bateson, E; Gribble, P L

1997-12-01

The kinematics of human jaw movements were assessed in terms of the three orientation angles and three positions that characterize the motion of the jaw as a rigid body. The analysis focused on the identification of the jaw's independent movement dimensions, and was based on an examination of jaw motion paths that were plotted in various combinations of linear and angular coordinate frames. Overall, both behaviors were characterized by independent motion in four degrees of freedom. In general, when jaw movements were plotted to show orientation in the sagittal plane as a function of horizontal position, relatively straight paths were observed. In speech, the slopes and intercepts of these paths varied depending on the phonetic material. The vertical position of the jaw was observed to shift up or down so as to displace the overall form of the sagittal plane motion path of the jaw. Yaw movements were small but independent of pitch, and vertical and horizontal position. In mastication, the slope and intercept of the relationship between pitch and horizontal position were affected by the type of food and its size. However, the range of variation was less than that observed in speech. When vertical jaw position was plotted as a function of horizontal position, the basic form of the path of the jaw was maintained but could be shifted vertically. In general, larger bolus diameters were associated with lower jaw positions throughout the movement. The timing of pitch and yaw motion differed. The most common pattern involved changes in pitch angle during jaw opening followed by a phase predominated by lateral motion (yaw). Thus, in both behaviors there was evidence of independent motion in pitch, yaw, horizontal position, and vertical position. This is consistent with the idea that motions in these degrees of freedom are independently controlled.

Influence of Thickness and Contact Surface Geometry of Condylar Stem of TMJ Implant on Its Stability

NASA Astrophysics Data System (ADS)

Arabshahi, Zohreh; Kashani, Jamal; Kadir, Mohammed Rafiq Abdul; Azari, Abbas

The aim of this study is to examine the effect thickness and contact surface geometry of condylar stem of TMJ implant on its stability in total reconstruction system and evaluate the micro strain resulted in bone at fixation screw holes in jaw bone embedded with eight different designs of temporomandibular joint implants. A three dimensional model of a lower mandible of an adult were developed from a Computed Tomography scan images. Eight different TMJ implant designs and fixation screws were modeled. Three dimensional finite element models of eight implanted mandibles were analyzed. The forces assigned to the masticatory muscles for incisal clenching were applied consisting of nine important muscular loads. In chosen loading condition, The results indicated that the anatomical curvature contact surface design of TMJ implant can moderately improve the stability and the strain resulted in fixation screw holes in thinner TMJ implant was diminished in comparison with other thicknesses.

Alendronate-associated osteonecrosis of the jaws: A review of the main topics

PubMed Central

Paiva-Fonseca, Felipe; Santos-Silva, Alan R.; Della-Coletta, Ricardo; Vargas, Pablo A.

2014-01-01

Bisphosphonates is a group of inorganic pyrophosphates analogues that suppress bone resorption by inducing osteoclast inactivation, being frequently used for management of diseases affecting bone metabolism, bone metastases and bone tumors. However, since 2003 many cases describing the presence of necrotic bone exposures in the jaws have been described in patients receiving these drugs, what represent a significant complication of bisphosphonates treatment. The overall incidence of bisphosphonate-related osteonecrosis of the jaws is low, ranging from 0.7% to 12%, mainly observed in those patients receiving intravenously treatment. Osteonecrosis of the jaws associated to oral bisphosphonate, particularly alendronate, has also been reported by a number of authors. Considering that alendronate is one of the most used drugs worldwide, specially for treatment of osteoporosis, a better understanding of osteonecrosis of the jaws related to its use and how to manage these patients is extremely important. Therefore, in the current manuscript the authors aim to review the most important topics related to this pathological presentation. Key words:Bisphosphonates, alendronate, bisphosphonate-related osteonecrosis of the jaws, osteonecrosis. PMID:23986020

Postmating sexual selection and the enigmatic jawed genitalia of Callosobruchus subinnotatus

PubMed Central

Rönn, Johanna Liljestrand; Schilthuizen, Menno; Arnqvist, Göran

2017-01-01

ABSTRACT Insect genitalia exhibit rapid divergent evolution. Truly extraordinary structures have evolved in some groups, presumably as a result of postmating sexual selection. To increase our understanding of this phenomenon, we studied the function of one such structure. The male genitalia of Callosobruchus subinnotatus (Coleoptera: Bruchinae) contain a pair of jaw-like structures with unknown function. Here, we used phenotypic engineering to ablate the teeth on these jaws. We then experimentally assessed the effects of ablation of the genital jaws on mating duration, ejaculate weight, male fertilization success and female fecundity, using a double-mating experimental design. We predicted that copulatory wounding in females should be positively related to male fertilization success; however, we found no significant correlation between genital tract scarring in females and male fertilization success. Male fertilization success was, however, positively related to the amount of ejaculate transferred by males and negatively related to female ejaculate dumping. Ablation of male genital jaws did not affect male relative fertilization success but resulted in a reduction in female egg production. Our results suggest that postmating sexual selection in males indeed favors these genital jaws, not primarily through an elevated relative success in sperm competition but by increasing female egg production. PMID:28583926

Zoledronate Effects on Systemic and Jaw Osteopenias in Ovariectomized Periostin-Deficient Mice

PubMed Central

Bonnet, Nicolas; Lesclous, Philippe; Saffar, Jean Louis; Ferrari, Serge

2013-01-01

Osteoporosis and periodontal disease (PD) are frequently associated in the elderly, both concurring to the loss of jaw alveolar bone and finally of teeth. Bisphosphonates improve alveolar bone loss but have also been associated with osteonecrosis of the jaw (ONJ), particularly using oncological doses of zoledronate. The effects and therapeutic margin of zoledronate on jaw bone therefore remain uncertain. We reappraised the efficacy and safety of Zoledronate (Zol) in ovariectomized (OVX) periostin (Postn)-deficient mice, a unique genetic model of systemic and jaw osteopenia. Compared to vehicle, Zol 1M (100 µg/kg/month) and Zol 1W (100 µg/kg/week) for 3 months both significantly improved femur BMD, trabecular bone volume on tissue volume (BV/TV) and cortical bone volume in both OVX Postn+/+ and Postn−/− (all p<0.01). Zol 1M and Zol 1W also improved jaw alveolar and basal BV/TV, although the highest dose (Zol 1W) was less efficient, particularly in Postn−/−. Zol decreased osteoclast number and bone formation indices, i.e. MAR, MPm/BPm and BFR, independently in Postn−/− and Postn+/+, both in the long bones and in deep jaw alveolar bone, without differences between Zol doses. Zol 1M and Zol 1W did not reactivate inflammation nor increase fibrous tissue in the bone marrow of the jaw, whereas the distance between the root and the enamel of the incisor (DRI) remained high in Postn−/− vs Postn+/+ confirming latent inflammation and lack of crestal alveolar bone. Zol 1W and Zol 1M decreased osteocyte numbers in Postn−/− and Postn+/+ mandible, and Zol 1W increased the number of empty lacunae in Postn−/−, however no areas of necrotic bone were observed. These results demonstrate that zoledronate improves jaw osteopenia and suggest that in Postn−/− mice, zoledronate is not sufficient to induce bone necrosis. PMID:23505553

Jaw-Opening Reflex and Corticobulbar Motor Excitability Changes During Quiet Sleep in Non-Human Primates

PubMed Central

Yao, Dongyuan; Lavigne, Gilles J.; Lee, Jye-Chang; Adachi, Kazunori; Sessle, Barry J.

2013-01-01

Study Objective: To test the hypothesis that the reflex and corticobulbar motor excitability of jaw muscles is reduced during sleep. Design: Polysomnographic recordings in the electrophysiological study. Setting: University sleep research laboratories. Participants and Interventions: The reflex and corticobulbar motor excitability of jaw muscles was determined during the quiet awake state (QW) and quiet sleep (QS) in monkeys (n = 4). Measurements and Results: During QS sleep, compared to QW periods, both tongue stimulation-evoked jaw-opening reflex peak and root mean square amplitudes were significantly decreased with stimulations at 2-3.5 × thresholds (P < 0.001). The jaw-opening reflex latency during sleep was also significantly longer than during QW. Intracortical microstimulation (ICMS) within the cortical masticatory area induced rhythmic jaw movements at a stable threshold (≤ 60 μA) during QW; but during QS, ICMS failed to induce any rhythmic jaw movements at the maximum ICMS intensity used, although sustained jaw-opening movements were evoked at significantly increased threshold (P < 0.001) in one of the monkeys. Similarly, during QW, ICMS within face primary motor cortex induced orofacial twitches at a stable threshold (≤ 35 μA), but the ICMS thresholds were elevated during QS. Soon after the animal awoke, rhythmic jaw movements and orofacial twitches could be evoked at thresholds similar to those before QS. Conclusions: The results suggest that the excitability of reflex and corticobulbar-evoked activity in the jaw motor system is depressed during QS. Citation: Yao D; Lavigne GJ; Lee JC; Adachi K; Sessle BJ. Jaw-opening reflex and corticobulbar motor excitability changes during quiet sleep in non-human primates. SLEEP 2013;36(2):269-280. PMID:23372275

Bite Forces and Their Measurement in Dogs and Cats.

PubMed

Kim, Se Eun; Arzi, Boaz; Garcia, Tanya C; Verstraete, Frank J M

2018-01-01

Bite force is generated by the interaction of the masticatory muscles, the mandibles and maxillae, the temporomandibular joints (TMJs), and the teeth. Several methods to measure bite forces in dogs and cats have been described. Direct in vivo measurement of a bite in dogs has been done; however, bite forces were highly variable due to animal volition, situation, or specific measurement technique. Bite force has been measured in vivo from anesthetized dogs by electrical stimulation of jaw adductor muscles, but this may not be reflective of volitional bite force during natural activity. In vitro bite forces have been estimated by calculation of the force produced using mechanical equations representing the jaw adductor muscles and of the mandible and skull structure Bite force can be estimated in silico using finite element analysis (FEA) of the computed model of the anatomical structures. FEA can estimate bite force in extinct species; however, estimates may be lower than the measurements in live animals and would have to be validated specifically in domestic dogs and cats to be reliable. The main factors affecting the bite forces in dogs and cats are body weight and the skull's morphology and size. Other factors such as oral pain, TMJ disorders, masticatory muscle atrophy, and malocclusion may also affect bite force. Knowledge of bite forces in dogs and cats is essential for various clinical and research fields such as the development of implants, materials, and surgical techniques as well as for forensic medicine. This paper is a summary of current knowledge of bite forces in dogs and cats, including the effect of measurement methods and of other factors.

Description of the chimaerid jaw and its phylogenetic origins.

PubMed

Grogan, Eileen D; Lund, Richard; Didier, Dominique

1999-01-01

Anatomical delineation of the holocephalan palatoquadrate has proven to be difficult and, so, has been an extensively debated topic as it relates to the evolutionary derivation of jaws, modes of jaw suspension, and the interrelationships of the hondrichthyes (Elasmobranchii and Holocephali). Embryological analyses of the chimaerid jaw and cranium are presented to provide an anatomical description of the palatoquadrate in modern chimaerids. The palatoquadrate fuses, anteriorly, to the nasal capsule early in development. This marks the first point of contact between the mandibular arch and cranium. Orbitonasal canal foramina delineate the dorsal palatoquadrate margin. The posteriormost margin is marked by fusion of the upper jaw with trabecular and parachordal cartilages in the region of the efferent eudobranchial artery foramen and by a suborbitally positioned basitrabecular cartilage. This basitrabecula generates a subocular shelf as it fuses medially to the parachordal cartilage and posteriorly to the postorbital wall and cranial otic process. The results of these analyses are related to morphological studies of Paleozoic chondrichthyan fishes, particularly the autodiastylic paraselachians that represent morphological intermediates to selachians and holocephalans. The paraselachian basitrabecular, which was mechanically fundamental to stabilizing the free autodiastylic upper jaw and a hyoid operculum, is shown to correlate with the suborbital basitrabecular of today's chimaerids. Further analyses of both extant and fossil data permit us to conclude that the primordial chondrichthyan palatoquadrate did not extend posteriorly to include a palatoquadrate-derived otic process. Rather, the posteriormost extent of this element is primitively found within the limits of the orbit and is demarcated by the highly conserved basitrabecular element. The collective analyses support autodiastyly as the ancestral condition from which all fundamental suspensorial states are

Phylotranscriptomic consolidation of the jawed vertebrate timetree.

PubMed

Irisarri, Iker; Baurain, Denis; Brinkmann, Henner; Delsuc, Frédéric; Sire, Jean-Yves; Kupfer, Alexander; Petersen, Jörn; Jarek, Michael; Meyer, Axel; Vences, Miguel; Philippe, Hervé

2017-09-01

Phylogenomics is extremely powerful but introduces new challenges as no agreement exists on "standards" for data selection, curation and tree inference. We use jawed vertebrates (Gnathostomata) as model to address these issues. Despite considerable efforts in resolving their evolutionary history and macroevolution, few studies have included a full phylogenetic diversity of gnathostomes and some relationships remain controversial. We tested a novel bioinformatic pipeline to assemble large and accurate phylogenomic datasets from RNA sequencing and find this phylotranscriptomic approach successful and highly cost-effective. Increased sequencing effort up to ca. 10Gbp allows recovering more genes, but shallower sequencing (1.5Gbp) is sufficient to obtain thousands of full-length orthologous transcripts. We reconstruct a robust and strongly supported timetree of jawed vertebrates using 7,189 nuclear genes from 100 taxa, including 23 new transcriptomes from previously unsampled key species. Gene jackknifing of genomic data corroborates the robustness of our tree and allows calculating genome-wide divergence times by overcoming gene sampling bias. Mitochondrial genomes prove insufficient to resolve the deepest relationships because of limited signal and among-lineage rate heterogeneity. Our analyses emphasize the importance of large curated nuclear datasets to increase the accuracy of phylogenomics and provide a reference framework for the evolutionary history of jawed vertebrates.

[Jaw osteosarcomas].

PubMed

Steve, M; Ernenwein, D; Chaine, A; Bertolus, C; Goudot, P; Ruhin-Poncet, B

2011-11-01

Osteosarcoma (OS) is the most frequent bone malignant tumor. It is usually found on long bones, 5 to 10% are located on jaws, accounting for 0.5 to 1% of all facial tumors. There is little published data which concerns only few patients. Our aim was to study retrospectively cases of facial bone OS in adults, and to compare our results with published data to suggest an optimal management scheme. Thirty-three patients were managed for an OS, from January 1997 to January 2007. Fourteen patients with a maxillary and mandibular OS, treated in first-intention in our unit, were included. The following data were analyzed: age; personal history; circumstance of discovery; clinical, functional, and physical signs; loco-regional extension and metastasis radiological investigation. The histological slides were systematically reviewed. The protocol, therapeutic outcome, and follow-up were studied. The mean age at diagnosis was 43. Swelling was the most frequent functional sign. The mean delay before management was 3.4 months. The most frequent radiological presentation was a lytic and hyperdense image. The diagnosis was suggested after CT scan in 57.1% of cases. The biopsy was correlated to the anatomopathological analysis in 78.6% of cases. The most common treatment was surgical exeresis completed by chemotherapy. The 5-year survival rate was 50%. Jaw OS are specific because of their localization and specific bone ultrastructure. Their management remains controversial: should they be managed like limb OS or treated more specifically? Neoadjuvant chemotherapy, even if it delays exeresis for 3 months, seems to stop the growth or reduce the tumor. An early anatomopathological analysis of the surgical piece determines adjuvant therapy. The negative prognostic factors are: maxillary localization because of limited exeresis margins, tumoral size, and osteoblastic sub-type. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Myofiber turnover is used to retrofit frog jaw muscles during metamorphosis.

PubMed

Alley, K E

1989-01-01

Metamorphic reorganization of the head in anuran amphibians entails abrupt restructuring of the jaw complex as larval feeding structures are transformed into their adult configurations. In this morphometric study, light microscopy wa used to analyze the larval maturation and metamorphic transfiguration of the adductor jaw muscles in the leopard frog (Rana pipiens). Larval jaw muscles, first established during embryogenesis, continue to grow by fiber addition until prometamorphosis, stage XII. Thereafter, fiber number remains stable but additional muscle growth continues by hypertrophy of the individual fibers until metamorphic climax. During metamorphic stages XIX-XXIII, a complete involution of all larval myofibers occurs. Simultaneously, within the same muscle beds, a second wave of myogenesis produces myoblasts which are the precursors of adult jaw myofibers. New muscle fibers continue to be added to these muscles well after the completion of metamorphosis; however, the total duration of the postmetamorphic myogenic period has not been defined. These observations provide clear evidence that the entir population of primary myofibers used in larval oral activity disappears from the adductor muscle beds and is replaced by a second wave of myogenesis commencing during climax. These findings indicate that the adductor jaw muscles are prepared for adult feeding by a complicated cellular process that retrofits existing muscle beds with a completely new complement of myofibers.

Jaw Function in Smilodon fatalis: A Reevaluation of the Canine Shear-Bite and a Proposal for a New Forelimb-Powered Class 1 Lever Model

PubMed Central

Brown, Jeffrey G.

2014-01-01

The jaw function of Smilodon fatalis has long been a source of debate. Although modern-day lions subdue large prey through the use of a suffocating throat bite, the dramatically elongated maxillary canines of S. fatalis suggest an alternative bite mechanism. The current literature favors a “canine shear-bite,” in which the depression of the cranium by the ventral neck flexors assists the mandibular adductors in closing the jaws. Although the model makes intuitive sense and appears to be supported by scientific data, the mechanical feasibility of “neck-powered” biting has not been experimentally demonstrated. In the present study, the computer-assisted manipulation of digitized images of a high-quality replica of an S. fatalis neck and skull shows that a rotation of the cranium by the ventral neck flexors will not result in jaw closure. Instead, the cranium and mandible rotate ventrally together (at the atlantooccipital joint), and the jaws remain in an open configuration. The only manner by which rotation of the cranium can simultaneously result in jaw closure is by an anterior rotation at the temporomandibular joint. Based on this finding, the author proposes a new Class 1 lever mechanism for S. fatalis jaw function. In this model, the mandible is immobilized against the neck of the prey and a dorsally directed force from the extension of the forelimbs rotates the cranium anteriorly at the temporomandibular joint. The maxillary canines pierce the prey’s neck and assist in clamping the ventral neck structures. The model is based on a maximum gape angle of approximately 90° and incorporates a secondary virtual point of rotation located slightly anteroventral to the temporomandibular joint. The Class 1 Lever Model is mechanically feasible, consistent with current data on S. fatalis anatomy and ecology, and may provide a basis for similar studies on other fossil taxa. PMID:25272032

Wake measurements of a dechirper jaw with nonzero tilt angle

NASA Astrophysics Data System (ADS)

Bane, Karl; Guetg, Marc; Lutman, Alberto

2018-05-01

The RadiaBeam/SLAC dechirper at the Linac Coherent Light Source (LCLS) is being used as a fast kicker, by inducing transverse wakefields, to, e.g., facilitate Fresh-slice, two-color laser operation. The dechirper jaws are independently adjustable at both ends, and it is difficult to avoid leaving residual (longitudinal) tilt in them during setup. In this report we develop a model independent method of removing unknown tilt in a jaw. In addition, for a short uniform bunch passing by a single dechirper plate, we derive an explicit analytical formula for the transverse wake kick as function of average plate offset and tilt angle. We perform wake kick measurements for the different dechirper jaws of the RadiaBeam/SLAC dechirper, and find that the agreement between measurement and theory is excellent.

Evidence of behavioral co-option from context-dependent variation in mandible use in trap-jaw ants ( Odontomachus spp.)

NASA Astrophysics Data System (ADS)

Spagna, Joseph C.; Schelkopf, Adam; Carrillo, Tiana; Suarez, Andrew V.

2009-02-01

Evolutionary co-option of existing structures for new functions is a powerful yet understudied mechanism for generating novelty. Trap-jaw ants of the predatory genus Odontomachus are capable of some of the fastest self-propelled appendage movements ever recorded; their devastating strikes are not only used to disable and capture prey, but produce enough force to launch the ants into the air. We tested four Odontomachus species in a variety of behavioral contexts to examine if their mandibles have been co-opted for an escape mechanism through ballistic propulsion. We found that nest proximity makes no difference in interactions with prey, but that prey size has a strong influence on the suite of behaviors employed by the ants. In trials involving a potential threat (another trap-jaw ant species), vertical jumps were significantly more common in ants acting as intruders than in residents (i.e. a dangerous context), while horizontal jumps occurred at the same rate in both contexts. Additionally, horizontal jump trajectories were heavily influenced by the angle at which the substrate was struck and appear to be under little control by the ant. We conclude that while horizontal jumps may be accidental side-effects of strikes against hard surfaces, vertical escape jumps are likely intentional defensive behaviors that have been co-opted from the original prey-gathering and food-processing functions of Odontomachus jaws.

Expression of Msx-1 is suppressed in bisphosphonate associated osteonecrosis related jaw tissue-etiopathology considerations respecting jaw developmental biology-related unique features

PubMed Central

2010-01-01

Background Bone-destructive disease treatments include bisphosphonates and antibodies against the osteoclast differentiator, RANKL (aRANKL); however, osteonecrosis of the jaw (ONJ) is a frequent side-effect. Current models fail to explain the restriction of bisphosphonate (BP)-related and denosumab (anti-RANKL antibody)-related ONJ to jaws. Msx-1 is exclusively expressed in craniofacial structures and pivotal to cranial neural crest (CNC)-derived periodontal tissue remodeling. We hypothesised that Msx-1 expression might be impaired in bisphosphonate-related ONJ. The study aim was to elucidate Msx-1 and RANKL-associated signal transduction (BMP-2/4, RANKL) in ONJ-altered and healthy periodontal tissue. Methods Twenty ONJ and twenty non-BP exposed periodontal samples were processed for RT-PCR and immunohistochemistry. An automated staining-based alkaline phosphatase-anti-alkaline phosphatase method was used to measure the stained cells:total cell-number ratio (labelling index, Bonferroni adjustment). Real-time RT-PCR was performed on ONJ-affected and healthy jaw periodontal samples (n = 20 each) to quantitatively compare Msx-1, BMP-2, RANKL, and GAPDH mRNA levels. Results Semi-quantitative assessment of the ratio of stained cells showed decreased Msx-1 and RANKL and increased BMP-2/4 (all p < 0.05) expression in ONJ-adjacent periodontal tissue. ONJ tissue also exhibited decreased relative gene expression for Msx-1 (p < 0.03) and RANKL (p < 0.03) and increased BMP-2/4 expression (p < 0.02) compared to control. Conclusions These results explain the sclerotic and osteopetrotic changes of periodontal tissue following BP application and substantiate clinical findings of BP-related impaired remodeling specific to periodontal tissue. RANKL suppression substantiated the clinical finding of impaired bone remodelling in BP- and aRANKL-induced ONJ-affected bone structures. Msx-1 suppression in ONJ-adjacent periodontal tissue suggested a bisphosphonate-related impairment in

Expression of Msx-1 is suppressed in bisphosphonate associated osteonecrosis related jaw tissue-etiopathology considerations respecting jaw developmental biology-related unique features.

PubMed

Wehrhan, Falk; Hyckel, Peter; Ries, Jutta; Stockmann, Phillip; Nkenke, Emeka; Schlegel, Karl A; Neukam, Friedrich W; Amann, Kerstin

2010-10-13

Bone-destructive disease treatments include bisphosphonates and antibodies against the osteoclast differentiator, RANKL (aRANKL); however, osteonecrosis of the jaw (ONJ) is a frequent side-effect. Current models fail to explain the restriction of bisphosphonate (BP)-related and denosumab (anti-RANKL antibody)-related ONJ to jaws. Msx-1 is exclusively expressed in craniofacial structures and pivotal to cranial neural crest (CNC)-derived periodontal tissue remodeling. We hypothesised that Msx-1 expression might be impaired in bisphosphonate-related ONJ. The study aim was to elucidate Msx-1 and RANKL-associated signal transduction (BMP-2/4, RANKL) in ONJ-altered and healthy periodontal tissue. Twenty ONJ and twenty non-BP exposed periodontal samples were processed for RT-PCR and immunohistochemistry. An automated staining-based alkaline phosphatase-anti-alkaline phosphatase method was used to measure the stained cells:total cell-number ratio (labelling index, Bonferroni adjustment). Real-time RT-PCR was performed on ONJ-affected and healthy jaw periodontal samples (n = 20 each) to quantitatively compare Msx-1, BMP-2, RANKL, and GAPDH mRNA levels. Semi-quantitative assessment of the ratio of stained cells showed decreased Msx-1 and RANKL and increased BMP-2/4 (all p < 0.05) expression in ONJ-adjacent periodontal tissue. ONJ tissue also exhibited decreased relative gene expression for Msx-1 (p < 0.03) and RANKL (p < 0.03) and increased BMP-2/4 expression (p < 0.02) compared to control. These results explain the sclerotic and osteopetrotic changes of periodontal tissue following BP application and substantiate clinical findings of BP-related impaired remodeling specific to periodontal tissue. RANKL suppression substantiated the clinical finding of impaired bone remodelling in BP- and aRANKL-induced ONJ-affected bone structures. Msx-1 suppression in ONJ-adjacent periodontal tissue suggested a bisphosphonate-related impairment in cellular differentiation that occurred

Hyperparathyroidism-jaw tumour syndrome detected by aggressive generalized osteitis fibrosa cystica.

PubMed

Guerrouani, Alae; Rzin, Abdelkader; El Khatib, Karim

2013-01-01

Severe hyperparathyroidism can affect bone metabolism and be in the origine of multiple brown tumours (generalized osteitis fibrosa cystica). When associated with fibro-ossifying tumours of the jaw, it realizes a rare genetic syndrome referred as Hyperparathyroidism-jaw tumour HPT-JT. We report the case of a patient we treated for HPT-JT, and literature review.

Directional selection has shaped the oral jaws of Lake Malawi cichlid fishes.

PubMed

Albertson, R Craig; Streelman, J Todd; Kocher, Thomas D

2003-04-29

East African cichlid fishes represent one of the most striking examples of rapid and convergent evolutionary radiation among vertebrates. Models of ecological speciation would suggest that functional divergence in feeding morphology has contributed to the origin and maintenance of cichlid species diversity. However, definitive evidence for the action of natural selection has been missing. Here we use quantitative genetics to identify regions of the cichlid genome responsible for functionally important shape differences in the oral jaw apparatus. The consistent direction of effects for individual quantitative trait loci suggest that cichlid jaws and teeth evolved in response to strong, divergent selection. Moreover, several chromosomal regions contain a disproportionate number of quantitative trait loci, indicating a prominent role for pleiotropy or genetic linkage in the divergence of this character complex. Of particular interest are genomic intervals with concerted effects on both the length and height of the lower jaw. Coordinated changes in this area of the oral jaw apparatus are predicted to have direct consequences for the speed and strength of jaw movement. Taken together, our results imply that the rapid and replicative nature of cichlid trophic evolution is the result of directional selection on chromosomal packages that encode functionally linked aspects of the craniofacial skeleton.

The Rise of Jaw Protrusion in Spiny-Rayed Fishes Closes the Gap on Elusive Prey.

PubMed

Bellwood, David R; Goatley, Christopher H R; Bellwood, Orpha; Delbarre, Daniel J; Friedman, Matt

2015-10-19

Jaw protrusion is one of the most important innovations in vertebrate feeding over the last 400 million years [1, 2]. Protrusion enables a fish to rapidly decrease the distance between itself and its prey [2, 3]. We assessed the evolution and functional implications of jaw protrusion in teleost fish assemblages from shallow coastal seas since the Cretaceous. By examining extant teleost fishes, we identified a robust morphological predictor of jaw protrusion that enabled us to predict the extent of jaw protrusion in fossil fishes. Our analyses revealed increases in both average and maximum jaw protrusion over the last 100 million years, with a progressive increase in the potential impact of fish predation on elusive prey. Over this period, the increase in jaw protrusion was initially driven by a taxonomic restructuring of fish assemblages, with an increase in the proportion of spiny-rayed fishes (Acanthomorpha), followed by an increase in the extent of protrusion within this clade. By increasing the ability of fishes to catch elusive prey [2, 4], jaw protrusion is likely to have fundamentally changed the nature of predator-prey interactions and may have contributed to the success of the spiny-rayed fishes, the dominant fish clade in modern oceans [5]. Copyright © 2015 Elsevier Ltd. All rights reserved.

Maintenance of weight loss in obese patients after jaw wiring.

PubMed Central

Garrow, J S; Gardiner, G T

1981-01-01

In treatment of obesity restriction of food intake is necessary to achieve good results. Various operations have been devised to prevent patients overeating, but in this study jaw wiring was used to limit food intake. This procedure produces weight loss in obese patients but when the wires are removed the weight is usually regained. This report studied a group of patients whose weight loss was maintained after the wires were removed. A nylon cord fastened round the waist of the patient after weight reduction was found to act as a psychological barrier to weight gain. Seven patients were followed for 4-14 months after removal of jaw wires and regained a mean of only 5.6 kg of the 31.8 kg lost while their jaws were wired. This procedure compares favourably with other treatments for severe obesity. PMID:6783203

Feeding behavior, diet, and the functional consequences of jaw form in orangutans, with implications for the evolution of Pongo.

PubMed

Taylor, Andrea B

2006-04-01

Orangutans are amongst the most craniometrically variable of the extant great apes, yet there has been no attempt to explicitly link this morphological variation with observed differences in behavioral ecology. This study explores the relationship between feeding behavior, diet, and mandibular morphology in orangutans. All orangutans prefer ripe, pulpy fruit when available. However, some populations of Bornean orangutans (Pongo pygmaeus morio and P. p. wurmbii) rely more heavily on bark and relatively tough vegetation during periods of low fruit yield than do Sumatran orangutans (Pongo abelii). I tested the hypothesis that Bornean orangutans exhibit structural features of the mandible that provide greater load resistance abilities to masticatory and incisal forces. Compared to P. abelii, P. p. morio exhibits greater load resistance abilities as reflected in a relatively deeper mandibular corpus, deeper and wider mandibular symphysis, and relatively greater condylar area. P. p. wurmbii exhibits most of these same morphologies, and in all comparisons is either comparable in jaw proportions to P. p. morio, or intermediate between P. p. morio and P. abelii. These data indicate that P. p. morio and P. p. wurmbii are better suited to resisting large and/or frequent jaw loads than P. abelii. Using these results, I evaluated mandibular morphology in P. p. pygmaeus, a Bornean orangutan population whose behavioral ecology is poorly known. Pongo p. pygmaeus generally exhibits relatively greater load resistance capabilities than P. abelii, but less than P. p. morio. These results suggest that P. p. pygmaeus may consume greater amounts of tougher and/or more obdurate foods than P. abelii, and that consumption of such foods may intensify amongst Bornean orangutan populations. Finally, data from this study are used to evaluate variation in craniomandibular morphology in Khoratpithecus piriyai, possibly the earliest relative of Pongo from the late Miocene of Thailand, and the late

SU-G-BRA-14: Dose in a Rigidly Moving Phantom with Jaw and MLC Compensation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chao, E; Lucas, D

Purpose: To validate dose calculation for a rigidly moving object with jaw motion and MLC shifts to compensate for the motion in a TomoTherapy™ treatment delivery. Methods: An off-line version of the TomoTherapy dose calculator was extended to perform dose calculations for rigidly moving objects. A variety of motion traces were added to treatment delivery plans, along with corresponding jaw compensation and MLC shift compensation profiles. Jaw compensation profiles were calculated by shifting the jaws such that the center of the treatment beam moved by an amount equal to the motion in the longitudinal direction. Similarly, MLC compensation profiles weremore » calculated by shifting the MLC leaves by an amount that most closely matched the motion in the transverse direction. The same jaw and MLC compensation profiles were used during simulated treatment deliveries on a TomoTherapy system, and film measurements were obtained in a rigidly moving phantom. Results: The off-line TomoTherapy dose calculator accurately predicted dose profiles for a rigidly moving phantom along with jaw motion and MLC shifts to compensate for the motion. Calculations matched film measurements to within 2%/1 mm. Jaw and MLC compensation substantially reduced the discrepancy between the delivered dose distribution and the calculated dose with no motion. For axial motion, the compensated dose matched the no-motion dose within 2%/1mm. For transverse motion, the dose matched within 2%/3mm (approximately half the width of an MLC leaf). Conclusion: The off-line TomoTherapy dose calculator accurately computes dose delivered to a rigidly moving object, and accurately models the impact of moving the jaws and shifting the MLC leaf patterns to compensate for the motion. Jaw tracking and MLC leaf shifting can effectively compensate for the dosimetric impact of motion during a TomoTherapy treatment delivery.« less

Anti-resorptive osteonecrosis of the jaws: facts forgotten, questions answered, lessons learned.

PubMed

Carlson, Eric R; Schlott, Benjamin J

2014-05-01

Osteonecrosis of the jaws associated with bisphosphonate and other anti-resorptive medications (ARONJ) has historically been a poorly understood disease process in terms of its pathophysiology, prevention and treatment since it was originally described in 2003. In association with its original discovery 11 years ago, non-evidence based speculation of these issues have been published in the international literature and are currently being challenged. A critical analysis of cancer patients with ARONJ, for example, reveals that their osteonecrosis is nearly identical to that of cancer patients who are naive to anti-resorptive medications. In addition, osteonecrosis of the jaws is not unique to patients exposed to anti-resorptive medications, but is also seen in patients with osteomyelitis and other pathologic processes of the jaws. This article represents a review of facts forgotten, questions answered, and lessons learned in general regarding osteonecrosis of the jaws. Copyright © 2014 Elsevier Inc. All rights reserved.

Actinomyces osteomyelitis in bisphosphonate-related osteonecrosis of the jaw (BRONJ): the missing link?

PubMed

De Ceulaer, J; Tacconelli, E; Vandecasteele, S J

2014-11-01

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a rare complication of bisphosphonate treatment characterized by the development of exposed, necrotic bone in the jaw with inflammatory signs. The pathogenesis of BRONJ is not yet fully understood. This review analyzes the evidence supporting the hypothesis that BRONJ may be considered as a bisphosphonate-induced Actinomyces infection of the jaw according to the modified Koch's postulates. The main arguments relies on the following factors: (1) the high prevalence of isolation of Actinomyces from bone BRONJ lesions (73.2 % in retrospective series); (2) the similar pathological appearance of BRONJ and Actinomyces osteomyelitis in most studies, although BRONJ lesions without inflammation have been reported; (3) the high incidence of events that disrupt the normal mucosal barrier as a necessary trigger to develop BRONJ in bisphosphonate-exposed patients; (4) the predilection of bisphosphonate-induced osteonecrosis for the bones of the jaws; and (5) the favorable response of BRONJ on treatment that is active on Actinomyces. If BRONJ confirms to be a bisphosphonate-induced Actinomyces osteomyelitis of the jaw, this has major consequences for the prevention and treatment of this condition.

Heterogeneous conservation of Dlx paralog co-expression in jawed vertebrates.

PubMed

Debiais-Thibaud, Mélanie; Metcalfe, Cushla J; Pollack, Jacob; Germon, Isabelle; Ekker, Marc; Depew, Michael; Laurenti, Patrick; Borday-Birraux, Véronique; Casane, Didier

2013-01-01

The Dlx gene family encodes transcription factors involved in the development of a wide variety of morphological innovations that first evolved at the origins of vertebrates or of the jawed vertebrates. This gene family expanded with the two rounds of genome duplications that occurred before jawed vertebrates diversified. It includes at least three bigene pairs sharing conserved regulatory sequences in tetrapods and teleost fish, but has been only partially characterized in chondrichthyans, the third major group of jawed vertebrates. Here we take advantage of developmental and molecular tools applied to the shark Scyliorhinus canicula to fill in the gap and provide an overview of the evolution of the Dlx family in the jawed vertebrates. These results are analyzed in the theoretical framework of the DDC (Duplication-Degeneration-Complementation) model. The genomic organisation of the catshark Dlx genes is similar to that previously described for tetrapods. Conserved non-coding elements identified in bony fish were also identified in catshark Dlx clusters and showed regulatory activity in transgenic zebrafish. Gene expression patterns in the catshark showed that there are some expression sites with high conservation of the expressed paralog(s) and other expression sites with events of paralog sub-functionalization during jawed vertebrate diversification, resulting in a wide variety of evolutionary scenarios within this gene family. Dlx gene expression patterns in the catshark show that there has been little neo-functionalization in Dlx genes over gnathostome evolution. In most cases, one tandem duplication and two rounds of vertebrate genome duplication have led to at least six Dlx coding sequences with redundant expression patterns followed by some instances of paralog sub-functionalization. Regulatory constraints such as shared enhancers, and functional constraints including gene pleiotropy, may have contributed to the evolutionary inertia leading to high

Linear force device

NASA Technical Reports Server (NTRS)

Clancy, John P.

1988-01-01

The object of the invention is to provide a mechanical force actuator which is lightweight and manipulatable and utilizes linear motion for push or pull forces while maintaining a constant overall length. The mechanical force producing mechanism comprises a linear actuator mechanism and a linear motion shaft mounted parallel to one another. The linear motion shaft is connected to a stationary or fixed housing and to a movable housing where the movable housing is mechanically actuated through actuator mechanism by either manual means or motor means. The housings are adapted to releasably receive a variety of jaw or pulling elements adapted for clamping or prying action. The stationary housing is adapted to be pivotally mounted to permit an angular position of the housing to allow the tool to adapt to skewed interfaces. The actuator mechanisms is operated by a gear train to obtain linear motion of the actuator mechanism.

Regulation of eye and jaw colouration in three-spined stickleback Gasterosteus aculeatus.

PubMed

Franco-Belussi, L; De Oliveira, C; Sköld, H N

2018-03-25

Fish can change their skin and eye colour for background matching and signalling. Males of Gasterosteus aculeatus develop ornamental blue eyes and a red jaw during the reproductive season, colours that are further enhanced during courtship. Here, the effects of different hormones on physiological colour changes in the eyes and jaws of male and female G. aculeatus were investigated in vitro. In an in vivo experiment, G. aculeatus were injected with a receptor blocker of a pivotal hormone (noradrenaline) that controls colour change. In males, noradrenaline had aggregating effects on melanophore and erythrophore pigments resulting in blue eyes and a pale jaw, whereas melanocyte-concentrating hormone (MCH) and melatonin resulted in a pale jaw only. When noradrenalin was combined with melanocyte stimulating hormone (MSH) or prolactin, the jaw became red, while the eyes remained blue. In vivo injection of yohimbine, an alpha-2 adrenoreceptor blocker, resulted in dispersion of melanophore pigment in the eyes and inhibited the blue colouration. Altogether, the data suggest that noradrenalin has a pivotal role in the short-term enhancement of the ornamental colouration of male G. aculeatus, potentially together with MSH or prolactin. This study also found a sex difference in the response to MCH, prolactin and melatonin, which may result from different appearance strategies in males, versus the more cryptic females. © 2018 The Fisheries Society of the British Isles.

Bisphosphonates and osteonecrosis of the jaw.

PubMed

Shannon, Jodi; Shannon, John; Modelevsky, Steven; Grippo, Anne A

2011-12-01

Bisphosphonates are used worldwide as a successful treatment for people with osteoporosis, which is the major underlying cause of fractures in postmenopausal women and older adults. These agents are successful at increasing bone mass and bone trabecular thickness, decreasing the risk of fracture, and decreasing bone pain, enabling individuals to have better quality of life. Bisphosphonates are also used to treat multiple myeloma, bone metastasis, and Paget's disease; however, bisphosphonate treatment may result in negative side effects, including osteonecrosis of the jaw (ONJ). ONJ involves necrotic, exposed bone in the jaw, pain, possible secondary infection, swelling, painful lesions, and various dysesthesias, although less-severe cases may be asymptomatic. First-generation bisphosphonates, which do not contain nitrogen, are metabolized into a nonfunctional, cytotoxic analogue of adenosine triphosphate and cause osteoclast death by starvation. Second-generation bisphosphonates are nitrogen-containing agents; these inhibit osteoclast vesicular trafficking, membrane ruffling, morphology, and cytoskeletal arrangement by inhibiting farnesyl diphosphate synthase in the mevalonate pathway. Physicians treating older adults with osteoporosis and cancer should work together with dental practitioners, pharmacists, and other clinicians to inform individuals receiving bisphosphonates of their possible side effects and to suggest precautionary steps that may minimize the risk of osteonecrosis, particularly of the jaw. These include practicing good oral hygiene; scheduling regular dental examinations and cleanings; and cautioning people who are scheduling treatment for periodontal disease, oral and maxillofacial therapy, endodontics, implant placement, restorative dentistry, and prosthodontics. Recommendations for management of people with ONJ include an oral rinse, such as chlorhexidine, and antibiotics. © 2011, Copyright the Authors Journal compilation © 2011, The American

Three dimensional digital reconstruction of the jaw adductor musculature of the extinct marsupial giant Diprotodon optatum

PubMed Central

2014-01-01

The morphology and arrangement of the jaw adductor muscles in vertebrates reflects masticatory style and feeding processes, diet and ecology. However, gross muscle anatomy is rarely preserved in fossils and is, therefore, heavily dependent on reconstructions. An undeformed skull of the extinct marsupial, Diprotodon optatum, recovered from Pleistocene sediments at Bacchus Marsh in Victoria, represents the most complete and best preserved specimen of the species offering a unique opportunity to investigate functional anatomy. Computed tomography (CT) scans and digital reconstructions make it possible to visualise internal cranial anatomy and predict location and morphology of soft tissues, including muscles. This study resulted in a 3D digital reconstruction of the jaw adductor musculature of Diprotodon, revealing that the arrangement of muscles is similar to that of kangaroos and that the muscle actions were predominantly vertical. 3D digital muscle reconstructions provide considerable advantages over 2D reconstructions for the visualisation of the spatial arrangement of the individual muscles and the measurement of muscle properties (length, force vectors and volume). Such digital models can further be used to estimate muscle loads and attachment sites for biomechanical analyses. PMID:25165628

Three-dimensional finite element modelling of muscle forces during mastication.

PubMed

Röhrle, Oliver; Pullan, Andrew J

2007-01-01

This paper presents a three-dimensional finite element model of human mastication. Specifically, an anatomically realistic model of the masseter muscles and associated bones is used to investigate the dynamics of chewing. A motion capture system is used to track the jaw motion of a subject chewing standard foods. The three-dimensional nonlinear deformation of the masseter muscles are calculated via the finite element method, using the jaw motion data as boundary conditions. Motion-driven muscle activation patterns and a transversely isotropic material law, defined in a muscle-fibre coordinate system, are used in the calculations. Time-force relationships are presented and analysed with respect to different tasks during mastication, e.g. opening, closing, and biting, and are also compared to a more traditional one-dimensional model. The results strongly suggest that, due to the complex arrangement of muscle force directions, modelling skeletal muscles as conventional one-dimensional lines of action might introduce a significant source of error.

Central xanthoma of the jaw in association with Noonan syndrome.

PubMed

Olson, Nicholas J; Addante, Rocco R; de Abreu, Francine B; Memoli, Vincent A

2018-05-01

Xanthomas are histiocytic lesions of the skin, soft tissue and bone and are generally considered to be reactive in nature. When they arise in the bones of the jaw, they are referred to as central xanthomas. New evidence supports the hypothesis that central xanthomas are a separate and distinct entity from their extragnathic counterparts. Noonan syndrome (NS) is an autosomal dominant disorder that has been associated with giant cell lesions which also commonly occur in the jaw. We present a case of a 15year-old-male with NS who presented with a radiolucent lesion of the mandible that on excision, was found to be a central xanthoma. Although giant cell lesions have been well described in NS, xanthomas of the jaw have not been reported. We will also discuss the entities that must be excluded prior to making a diagnosis of central xanthoma, as this can affect both treatment and follow up. Copyright © 2018. Published by Elsevier Inc.

Effect of placement angle on the stability of loaded titanium microscrews in beagle jaws.

PubMed

Xu, Zhenrui; Wu, Yeke; Zhao, Lixing; Zhou, Yuqiao; Wei, Xing; Tang, Na; Feng, Xiaoxia; Tang, Tian; Zhao, Zhihe

2013-07-01

To evaluate the effect of insertion angle on stability of loaded titanium microscrews in beagle jaws. Forty-eight microscrews were inserted at four different angles (30°, 50°, 70°, and 90°) into the intraradicular zones of the mandibular first molars and third premolars of 12 beagles and immediately loaded with a force of 2 N for 8 weeks. Microcomputed tomography (micro-CT) and biomechanical pull-out tests were used to assess osseointegration of the interface. All micro-CT parameters and maximum pull-out force (FMAX) of the microscrews were affected by insertion angles of microscrews. Higher micro-CT parameters and FMAX were seen for implants inserted at angles between 50° and 70° (P < .05). Excessive oblique and vertical insertion angles resulted in reduced stability (P < .05). An insertion angle of 50° to 70° is more favorable than excessive oblique or vertical angles to achieve stability of microscrews.

The Effect of Jaw Position on Measures of Tongue Strength and Endurance

ERIC Educational Resources Information Center

Solomon, Nancy Pearl; Munson, Benjamin

2004-01-01

Assessment of tongue strength and endurance is common in research and clinical contexts. It is unclear whether the results reveal discrete function by the tongue or combined abilities of the tongue and jaw. One way to isolate the movement of the tongue is to constrain the jaw kinematically by using a bite block. In this study, 10 neurologically…

Aesthetic Treatment of Bruxism

PubMed Central

Aguilera, Shino Bay; Perico, Viviana Andrea

2017-01-01

Bruxism is a diurnal or nocturnal parafunctional activity that includes unconscious clenching, grinding, or bracing of the teeth. An extensive medical history should be taken in these patients so proper diagnosis can be made. Habits such as biting the tongue, cheeks or lips, chewing gum or eating seeds for many hours per day, biting nails, and/or biting hard objects, will cause and/or exacerbate pre-existing bruxism. The etiology of bruxism is uncertain, but it is hypothesized to be associated with genetic, structural, and psychosocial factors. Over time, chronic clenching of the jaw leads to hypertrophy of masseters and temporalis musculature causing the face to take on a masculine and square appearance. Patients commonly present to dermatology cosmetic practices wishing to have a more slim, softer appearing face. This review is the first paper to discuss aesthetic treatment options for complications of bruxism including masseter and temporalis hypertrophy and the associated accelerated aging of the lower face. PMID:28670358

Biomechanical analysis of the influence of friction in jaw joint disorders.

PubMed

Koolstra, J H

2012-01-01

Increased friction due to impaired lubrication in the jaw joint has been considered as one of the possible causes for internal joint disorders. A very common internal disorder in the jaw joint is an anteriorly dislocated articular disc. This is generally considered to contribute to the onset of arthritic injuries. Increase of friction as caused by impairment of lubrication is suspected to be a possible cause for such a disorder. The influence of friction was addressed by analysis of its effects on tensions and deformations of the cartilaginous structures in the jaw joint using computational biomechanical analysis. Jaw open-close movements were simulated while in one or two compartments of the right joint friction was applied in the articular contact. The left joint was treated as the healthy control. The simulations predicted that friction primarily causes increased shear stress in the articular cartilage layers, but hardly in the articular disc. This suggests that impaired lubrication may facilitate deterioration of the cartilage-subchondral bone unit of the articular surfaces. The results further suggest that increased friction is not a plausible cause for turning a normally functioning articular disc into an anteriorly dislocated one. Copyright © 2011 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Cross-bridge kinetics of fast and slow fibres of cat jaw and limb muscles: correlations with myosin subunit composition.

PubMed

Hoh, Joseph F Y; Li, Zhao-Bo; Qin, Han; Hsu, Michael K H; Rossmanith, Gunther H

2007-01-01

Mechanical properties of the jaw-closing muscles of the cat are poorly understood. These muscles are known to differ in myosin and fibre type compositions from limb muscles. This work aims to correlate mechanical properties of single fibres in cat jaw and limb muscles with their myosin subunit compositions. The stiffness minimum frequency, f(min), which reflects isometric cross-bridge kinetics, was measured in Ca(2+)-activated glycerinated fast and slow fibres from cat jaw and limb muscles for temperatures ranging between 15 and 30 degrees C by mechanical perturbation analysis. At 15 degrees C, f(min) was 0.5 Hz for limb-slow fibres, 4-6 Hz for jaw-slow fibres, and 10-13 Hz for limb-fast and jaw-fast fibres. The activation energy for f(min) obtained from the slope of the Arrhenius plot for limb-slow fibres was 30-40% higher than values for the other three types of fibres. SDS-PAGE and western blotting using highly specific antibodies verified that limb-fast fibres contained IIA or IIX myosin heavy chain (MyHC). Jaw-fast fibres expressed masticatory MyHC while both jaw-fast and jaw-slow fibres expressed masticatory myosin light chains (MLCs). The nucleotide sequences of the 3' ends of the slow MyHC cDNAs isolated from cat masseter and soleus cDNA libraries showed identical coding and 3'-untranslated regions, suggesting that jaw-slow and limb-slow fibres express the same slow MyHC gene. We conclude that the isometric cross-bridge cycling kinetics of jaw-fast and limb-fast fibres detected by f(min) are indistinguishable in spite of differences in MyHC and light chain compositions. However, jaw-slow fibres, in which the same slow MyHCs are found in combination with MLCs of the jaw type, show enhanced cross-bridge cycling kinetics and reduced activation energy for cross-bridge detachment.

Does evolutionary innovation in pharyngeal jaws lead to rapid lineage diversification in labrid fishes?

PubMed Central

2009-01-01

Background Major modifications to the pharyngeal jaw apparatus are widely regarded as a recurring evolutionary key innovation that has enabled adaptive radiation in many species-rich clades of percomorph fishes. However one of the central predictions of this hypothesis, that the acquisition of a modified pharyngeal jaw apparatus will be positively correlated with explosive lineage diversification, has never been tested. We applied comparative methods to a new time-calibrated phylogeny of labrid fishes to test whether diversification rates shifted at two scales where major pharyngeal jaw innovations have evolved: across all of Labridae and within the subclade of parrotfishes. Results Diversification patterns within early labrids did not reflect rapid initial radiation. Much of modern labrid diversity stems from two recent rapid diversification events; one within julidine fishes and the other with the origin of the most species-rich clade of reef-associated parrotfishes. A secondary pharyngeal jaw innovation was correlated with rapid diversification within the parrotfishes. However diversification rate shifts within parrotfishes are more strongly correlated with the evolution of extreme dichromatism than with pharyngeal jaw modifications. Conclusion The temporal lag between pharyngeal jaw modifications and changes in diversification rates casts doubt on the key innovation hypothesis as a simple explanation for much of the richness seen in labrids and scarines. Although the possession of a secondarily modified PJA was correlated with increased diversification rates, this pattern is better explained by the evolution of extreme dichromatism (and other social and behavioral characters relating to sexual selection) within Scarus and Chlorurus. The PJA-innovation hypothesis also fails to explain the most dominant aspect of labrid lineage diversification, the radiation of the julidines. We suggest that pharyngeal jaws might have played a more important role in enabling

An antiarch placoderm shows that pelvic girdles arose at the root of jawed vertebrates

PubMed Central

Zhu, Min; Yu, Xiaobo; Choo, Brian; Wang, Junqing; Jia, Liantao

2012-01-01

Almost all gnathostomes or jawed vertebrates (including osteichthyans, chondrichthyans, ‘acanthodians’ and most placoderms) possess paired pectoral and pelvic fins. To date, it has generally been believed that antiarch placoderms (extinct armoured jawed fishes from the Silurian–Devonian periods) lacked pelvic fins. The putative absence of pelvic fins is a key character bearing on the monophyly or paraphyly of placoderms. It also has far-reaching implications for studying the sequence of origin of pelvic girdles versus that of movable jaws in the course of vertebrate evolution. Parayunnanolepis xitunensis represents the only example of a primitive antiarch with extensive post-thoracic preservation, and its original description has been cited as confirming the primitive lack of pelvic fins in early antiarchs. Here, we present a revised description of Parayunnanolepis and offer the first unambiguous evidence for the presence of pelvic girdles in antiarchs. As antiarchs are placed at the base of the gnathostome radiation in several recent studies, our finding shows that all jawed vertebrates (including antiarch placoderms) primitively possess both pectoral and pelvic fins and that the pelvic fins did not arise within gnathostomes at a point subsequent to the origin of jaws. PMID:22219394

Case-Based Review of Osteonecrosis of the Jaw (ONJ) and Application of the International Recommendations for Management From the International Task Force on ONJ.

PubMed

Khan, Aliya A; Morrison, Archie; Kendler, David L; Rizzoli, Rene; Hanley, David A; Felsenberg, Dieter; McCauley, Laurie K; O'Ryan, Felice; Reid, Ian R; Ruggiero, Salvatore L; Taguchi, Akira; Tetradis, Sotirios; Watts, Nelson B; Brandi, Maria Luisa; Peters, Edmund; Guise, Teresa; Eastell, Richard; Cheung, Angela M; Morin, Suzanne N; Masri, Basel; Cooper, Cyrus; Morgan, Sarah L; Obermayer-Pietsch, Barbara; Langdahl, Bente L; Dabagh, Rana Al; Davison, K Shawn; Sándor, George K; Josse, Robert G; Bhandari, Mohit; El Rabbany, Mohamed; Pierroz, Dominique D; Sulimani, Riad; Saunders, Deborah P; Brown, Jacques P; Compston, Juliet

Osteonecrosis of the jaw (ONJ) has been associated with antiresorptive therapy in both oncology and osteoporosis patients. This debilitating condition is very rare and advances in diagnosis and management may now effectively reduce the risk of its development and offer valuable treatment options for affected patients. This paper provides a case-based review of ONJ and application of the International Task Force on ONJ (referred to as the "Task Force") recommendations for the diagnosis and management of ONJ. The Task Force was supported by 14 international societies and achieved consensus from representatives of these multidisciplinary societies on key issues pertaining to the diagnosis and management of ONJ. The frequency of ONJ in oncology patients receiving oncology doses of bisphosphonate (BP) or denosumab is estimated at 1%-15%, and the frequency in the osteoporosis patient population receiving much lower doses of BP or denosumab is estimated at 0.001%-0.01%. Although the diagnosis of ONJ is primarily clinical, imaging may be helpful in confirming the diagnosis and staging. In those with multiple risk factors for ONJ for whom major invasive oral surgery is being planned, interruption of BP or denosumab therapy (in cancer patients) is advised, if possible, before surgery, until the surgical site heals. Major oral surgery in this context could include multiple extractions if surgical extractions are required, not simple forceps extractions. ONJ development may be reduced by optimizing oral hygiene and postoperatively using topical and systemic antibiotics as appropriate. Periodontal disease should be managed before starting oncology doses of BP or denosumab. Local debridement may be successful in disease unresponsive to conservative therapy. Successful surgical intervention has been reported in those with stage 3 disease; less severe disease is best managed conservatively. Teriparatide may be helpful in healing ONJ lesions and may be considered in osteoporosis

Biting Force and Muscle Activity in Implant-Supported Single Mandibular Overdentures Opposing Fixed Maxillary Dentition.

PubMed

Al-Magaleh, Wafaʼa R; Abbas, Nadia A; Amer, Ashraf A; Abdelkader, Ann A; Bahgat, Basma

2016-04-01

This study aimed to investigate the relation between biting force and masticatory muscle activity in patients treated by 3 modalities of single mandibular dentures. Forty implants were placed in 10 patients with completely edentulous mandibles. The study was divided into 3 treatment stages. Initially, each patient received a conventional mandibular complete denture. At the second stage, 4 mandibular implants were placed and the denture was refitted to their abutments. Third stage comprised connecting the denture to the implants through ball attachments. During each treatment stage, maximum biting force and muscle activity were measured during maximum clenching and chewing of soft and hard food. Biting force demonstrated a statistically significant increase by time for the 3 treatment stages. The highest muscle activity was recorded for the conventional denture followed by the implant-supported overdenture without attachment, whereas the lowest values were recorded for the implant-supported overdenture with attachment. Biting force was related mainly to the quality of denture support. Muscle activity was higher in patients with conventional denture than with implant-supported prostheses (with or without attachments).

A dolphin lower jaw is a hydroacoustic antenna of the traveling wave

NASA Astrophysics Data System (ADS)

Ryabov, Vyacheslav A.

2003-10-01

The purpose of the work is the analysis of a possible function of mental foramens as channels through which the echo passes in the lower jaw fat body and the determination of a role of channels and a skull in formation of the directivity of the dolphin echolocation hearing. Concrete problems were studying of the lower jaw morphology, modeling and calculation of a dolphin, tursiops truncatus p., echolocation hearing beam pattern. The outcomes of the work indicate those morphological structures of the lower jaw; the left and right half represents two hydroacoustic receiving antennas of the traveling wave type, TWA farther. The mental foramens of a dolphin lower jaw represent nonequidistant array of waveguide delay lines, and determine the phase and amplitude distribution of each of the antenna's array. The beam pattern of the echolocation hearing was calculated with the usage of the TWA model, and the allowance of flat sound wave diffraction. The beam pattern shape is naturally determined by the echolocation hearing functionality. It is equally well adapted both for echolocation and for pulses echo detection. A steepness of the bearing characteristic is estimated; it reaches 0.7 dB per degree.

Beam feasibility study of a collimator with in-jaw beam position monitors

NASA Astrophysics Data System (ADS)

Wollmann, Daniel; Nosych, Andriy A.; Valentino, Gianluca; Aberle, Oliver; Aßmann, Ralph W.; Bertarelli, Alessandro; Boccard, Christian; Bruce, Roderik; Burkart, Florian; Calvo, Eva; Cauchi, Marija; Dallocchio, Alessandro; Deboy, Daniel; Gasior, Marek; Jones, Rhodri; Kain, Verena; Lari, Luisella; Redaelli, Stefano; Rossi, Adriana

2014-12-01

At present, the beam-based alignment of the LHC collimators is performed by touching the beam halo with both jaws of each collimator. This method requires dedicated fills at low intensities that are done infrequently and makes this procedure time consuming. This limits the operational flexibility, in particular in the case of changes of optics and orbit configuration in the experimental regions. The performance of the LHC collimation system relies on the machine reproducibility and regular loss maps to validate the settings of the collimator jaws. To overcome these limitations and to allow a continuous monitoring of the beam position at the collimators, a design with jaw-integrated Beam Position Monitors (BPMs) was proposed and successfully tested with a prototype (mock-up) collimator in the CERN SPS. Extensive beam experiments allowed to determine the achievable accuracy of the jaw alignment for single and multi-turn operation. In this paper, the results of these experiments are discussed. The non-linear response of the BPMs is compared to the predictions from electromagnetic simulations. Finally, the measured alignment accuracy is compared to the one achieved with the present collimators in the LHC.

Jaw muscle fiber type distribution in Hawaiian gobioid stream fishes: histochemical correlations with feeding ecology and behavior.

PubMed

Maie, Takashi; Meister, Andrew B; Leonard, Gerald L; Schrank, Gordon D; Blob, Richard W; Schoenfuss, Heiko L

2011-12-01

Differences in fiber type distribution in the axial muscles of Hawaiian gobioid stream fishes have previously been linked to differences in locomotor performance, behavior, and diet across species. Using ATPase assays, we examined fiber types of the jaw opening sternohyoideus muscle across five species, as well as fiber types of three jaw closing muscles (adductor mandibulae A1, A2, and A3). The jaw muscles of some species of Hawaiian stream gobies contained substantial red fiber components. Some jaw muscles always had greater proportions of white muscle fibers than other jaw muscles, independent of species. In addition, comparing across species, the dietary generalists (Awaous guamensis and Stenogobius hawaiiensis) had a lower proportion of white muscle fibers in all jaw muscles than the dietary specialists (Lentipes concolor, Sicyopterus stimpsoni, and Eleotris sandwicensis). Among Hawaiian stream gobies, generalist diets may favor a wider range of muscle performance, provided by a mix of white and red muscle fibers, than is typical of dietary specialists, which may have a higher proportion of fast-twitch white fibers in jaw muscles to help meet the demands of rapid predatory strikes or feeding in fast-flowing habitats. Copyright © 2011 Elsevier GmbH. All rights reserved.

Occlusal force, electromyographic activity of masticatory muscles and mandibular flexure of subjects with different facial types

PubMed Central

CUSTODIO, William; GOMES, Simone Guimarães Farias; FAOT, Fernanda; GARCIA, Renata Cunha Matheus Rodrigues; DEL BEL CURY, Altair Antoninha

2011-01-01

Objective The aim of this study was to evaluate whether vertical facial patterns influence maximal occlusal force (MOF), masticatory muscle electromyographic (EMG) activity, and medial mandibular flexure (MMF). Material and Methods Seventy-eight dentate subjects were divided into 3 groups by Ricketts's analysis: brachyfacial, mesofacial and dolychofacial. Maximum occlusal force in the molar region was bilaterally measured with a force transducer. The electromyographic activities of the masseter and anterior temporal muscles were recorded during maximal voluntary clenching. Medial mandibular flexure was calculated by subtracting the intermolar distance of maximum opening or protrusion from the distance in the rest position. The data were analyzed using ANOVA followed by Tukey's HSD test. The significance level was set at 5%. Results Data on maximum occlusal force showed that shorter faces had higher occlusal forces (P<0.0001). Brachyfacial subjects presented higher levels of masseter electromyographic activity and medial mandibular flexure, followed by the mesofacial and dolychofacial groups. Additionally, dolychofacial subjects showed significantly lower electromyographic temporalis activities (P<0.05). Conclusion Within the limitations of the study, it may be concluded that maximum occlusal force, masticatory muscle activity and medial mandibular flexure were influenced by the vertical facial pattern. PMID:21655772

Microbursts in JAWS depicted by Doppler radars, PAM, and aerial photographs

NASA Technical Reports Server (NTRS)

Fujita, T. T.; Wakimoto, R. M.

1983-01-01

Preliminary results obtained from the JAWS (Joint Airport Weather Studies) Project near Denver, Colorado in the spring and summer of 1982 using Doppler radar, PAM, and aerial photography are presented. The definitions of the microburst phenomenon are discussed, and statistics comparing NIMROD (Northern Illinois Meteorological Research On Downbursts) for the Midwest region are compared with JAWS for the High Plains region. Possible parent clouds of the microburst are considered, and an analysis of a macroburst/microburst event on July 14, 1982 is presented.

Bruxism: A Literature Review

PubMed Central

Reddy, S Varalakshmi; Kumar, M Praveen; Sravanthi, D; Mohsin, Abdul Habeeb Bin; Anuhya, V

2014-01-01

Parafunctional activities associated with the stomatognathic system include lip and cheek chewing, nail biting, and teeth clenching. Bruxism can be classified as awake or sleep bruxism. Patients with sleep bruxism are more likely to experience jaw pain and limitation of movement, than people who do not experience sleep bruxism. Faulty occlusion is one of the most common causes of bruxism that further leads to temporomandibular joint pain. Bruxism has been described in various ways by different authors. This article gives a review of the literature on bruxism since its first description. PMID:25628497

The Speech Focus Position Effect on Jaw-Finger Coordination in a Pointing Task

ERIC Educational Resources Information Center

Rochet-Capellan, Amelie; Laboissiere, Rafael; Galvan, Arturo; Schwartz, Jean-Luc

2008-01-01

Purpose: This article investigates jaw-finger coordination in a task involving pointing to a target while naming it with a 'CVCV (e.g., /'papa/) versus CV'CV (e.g., /pa'pa/) word. According to the authors' working hypothesis, the pointing apex (gesture extremum) would be synchronized with the apex of the jaw-opening gesture corresponding to the…

The Physiologic Development of Speech Motor Control: Lip and Jaw Coordination

PubMed Central

Green, Jordan R.; Moore, Christopher A.; Higashikawa, Masahiko; Steeve, Roger W.

2010-01-01

This investigation was designed to describe the development of lip and jaw coordination during speech and to evaluate the potential influence of speech motor development on phonologic development. Productions of syllables containing bilabial consonants were observed from speakers in four age groups (i.e., 1-year-olds, 2-year-olds, 6-year-olds, and young adults). A video-based movement tracking system was used to transduce movement of the upper lip, lower lip, and jaw. The coordinative organization of these articulatory gestures was shown to change dramatically during the first several years of life and to continue to undergo refinement past age 6. The present results are consistent with three primary phases in the development of lip and jaw coordination for speech: integration, differentiation, and refinement. Each of these developmental processes entails the existence of distinct coordinative constraints on early articulatory movement. It is suggested that these constraints will have predictable consequences for the sequence of phonologic development. PMID:10668666

Influence of botulinum toxin on rabbit jaw muscle activity and anatomy.

PubMed

Korfage, J A M; Wang, Jeffrey; Lie, S H J T J; Langenbach, Geerling E J

2012-05-01

Muscles can adapt their fiber properties to accommodate to new conditions. We investigated the extent to which a decrease in muscle activation can cause an adaptation of fiber properties in synergistic and antagonistic jaw muscles. Three months after the injection of botulinum toxin type A in one masseter (anterior or posterior) muscle changes in fiber type composition and fiber cross-sectional areas in jaw muscles were studied at the microscopic level. The injected masseter showed a steep increase in myosin type IIX fibers, whereas fast fibers decreased by about 50% in size. Depending on the injection site, both synergistic and antagonistic muscles showed a significant increase in the size of their fast IIA fibers, sometimes combined with an increased number of IIX fibers. Silencing the activity in the masseter not only causes changes in the fibers of the injected muscle but also leads to changes in other jaw muscles. Copyright © 2012 Wiley Periodicals, Inc.

Molecular phylogenetics and diversification of trap-jaw ants in the genera Anochetus and Odontomachus (Hymenoptera: Formicidae).

PubMed

Larabee, Fredrick J; Fisher, Brian L; Schmidt, Chris A; Matos-Maraví, Pável; Janda, Milan; Suarez, Andrew V

2016-10-01

Ants in the genera Anochetus and Odontomachus belong to one of the largest clades in the subfamily Ponerinae, and are one of four lineages of ants possessing spring-loaded "trap-jaws." Here we present results from the first global species-level molecular phylogenetic analysis of these trap-jaw ants, reconstructed from one mitochondrial, one ribosomal RNA, and three nuclear protein-coding genes. Bayesian and likelihood analyses strongly support reciprocal monophyly for the genera Anochetus and Odontomachus. Additionally, we found strong support for seven trap-jaw ant clades (four in Anochetus and three in Odontomachus) mostly concordant with geographic distribution. Ambiguity remains concerning the closest living non-trap-jaw ant relative of the Anochetus+Odontomachus clade, but Bayes factor hypothesis testing strongly suggests that trap-jaw ants evolved from a short mandible ancestor. Ponerine trap-jaw ants originated in the early Eocene (52.5Mya) in either South America or Southeast Asia, where they have radiated rapidly in the last 30million years, and subsequently dispersed multiple times to Africa and Australia. These results will guide future taxonomic work on the group and act as a phylogenetic framework to study the macroevolution of extreme ant mouthpart specialization. Copyright © 2016 Elsevier Inc. All rights reserved.

Comparison of Performance Characteristics of Oval Cup Forceps Versus Serrated Jaw Forceps in Gastric Biopsy.

PubMed

Sussman, Daniel A; Deshpande, Amar R; Shankar, Uday; Barkin, Jodie A; Medina, Ana Maria; Poppiti, Robert J; Cubeddu, Luigi X; Barkin, Jamie S

2016-08-01

Obtaining quality endoscopic biopsy specimens is vital in making successful histological diagnoses. The influence of forceps cup shape and size on quality of biopsy specimens is unclear. To identify whether oval cup or two different serrated jaw biopsy forceps could obtain specimens of superior size. Secondary endpoints were tissue adequacy, depth of tissue acquisition, and crush artifact. A single-center, prospective, pathologist-masked, randomized controlled trial was performed. In total 136 patients with a clinical indication for esophagogastroduodenoscopy with biopsy were randomized to receive serial biopsies with a large-capacity serrated forceps with jaw diameter 2.2 mm (SER1) and either a large-capacity oval forceps with jaw diameter 2.4 mm (OVL) or large-capacity serrated biopsy forceps with jaw diameter 2.4 mm (SER2) in two parallel groups. SER2 provided significantly larger specimens than did the other forceps (SER2 3.26 ± 1.09 vs. SER1 2.92 ± 0.88 vs. OVL 2.92 ± 0.76; p = 0.026), with an average size difference of 0.34 mm greater with SER2 compared to SER1 and OVL. OVL provided significantly deeper biopsies compared to SER1 and SER2 (p = 0.02), with 31 % of OVL biopsies reaching the submucosa. SER2 had significantly less crush artifact than SER1 and OVL (p < 0.0001). Serrated forceps provided larger samples compared to oval jaw forceps of the same size, with SER2 providing the largest specimen size. Oval cup forceps had deeper penetration of epithelium, while the larger jaw diameter serrated jaw forceps had less crush artifact. All three forceps provided specimens adequate for diagnostic purposes.

EMA assessment of tongue-jaw co-ordination during speech in dysarthria following traumatic brain injury.

PubMed

Bartle, Carly J; Goozée, Justine V; Scott, Dion; Murdoch, Bruce E; Kuruvilla, Mili

2006-05-01

To investigate the spatio-timing aspects of tongue-jaw co-ordination during speech in individuals with traumatic brain injury (TBI). It was hypothesized that both timing and spatial co-ordination would be affected by TBI. A group comparison design wherein Mann-Whitney U-tests were used to compare non-neurologically impaired individuals with individuals with TBI. Nine non-neurologically impaired adults and nine adults with TBI were involved in the study. Electromagnetic articulography (EMA) was used to track tongue and jaw movement during /t/ and /k/, embedded in sentence and syllable stimuli. Analysis of group data did not reveal a significant difference in spatio-timing tongue-jaw co-ordination between the control group and TBI group. On an individual basis, a proportion of individuals with TBI differed from non-neurologically impaired participants with regard to articulatory order and percentage of jaw contribution to /t/. EMA assessment results supported perceptual data; those adults who presented with severe articulatory disturbances exhibited the most deviant spatio-timing tongue-jaw co-ordination patterns. This finding could provide a new and specific direction for treatment, directed at combined movement patterns.

Sagittal Plane Kinematics of the Jaw and Hyolingual Apparatus During Swallowing in Macaca mulatta

PubMed Central

Iriarte-Diaz, Jose; Arce-McShane, Fritzie; Orsbon, Courtney P.; Brown, Kevin A.; Eastment, McKenna; Avivi-Arber, Limor; Sessle, Barry J.; Inoue, Makoto; Hatsopoulos, Nicholas G.; Ross, Callum F.

2018-01-01

Studies of mechanisms of feeding behavior are important in a society where aging- and disease-related feeding disorders are increasingly prevalent. It is important to evaluate the clinical relevance of animal models of the disease and the control. Our present study quantifies macaque hyolingual and jaw kinematics around swallowing cycles to determine the extent to which macaque swallowing resembles that of humans. One female and one male adult Macaca mulatta were trained to feed in a primate chair. Videofluoroscopy was used to record kinematics in a sagittal view during natural feeding on solid food, and the kinematics of the hyoid bone, thyroid cartilage, mandibular jaw, and anterior-, middle-, and posterior-tongue. Jaw gape cycles were defined by consecutive maximum gapes, and the kinematics of the swallow cycles were compared with those of the two consecutive non-swallow cycles preceding and succeeding the swallow cycles. Although there are size differences between macaques and humans, and macaques have shorter durations of jaw gape cycles and hyoid and thyroid upward movements, there are several important similarities between our macaque data and human data reported in the literature: (1) The durations of jaw gape cycles during swallow cycles are longer than those of non-swallow cycles as a result of an increased duration of the jaw-opening phase; (2) Hyoid and thyroid upward movement is linked with a posterior tongue movement and is faster during swallow than non-swallow cycles; (3) Tongue elevation propagates from anterior to posterior during swallow and non-swallow cycles. These findings suggest that macaques can be a useful experimental model for human swallowing studies. PMID:28528492

Vesicular glutamate transporter 1 (VGLUT1)- and VGLUT2-immunopositive axon terminals on the rat jaw-closing and jaw-opening motoneurons.

PubMed

Park, Sook Kyung; Ko, Sang Jin; Paik, Sang Kyoo; Rah, Jong-Cheol; Lee, Kea Joo; Bae, Yong Chul

2018-02-23

To provide information on the glutamatergic synapses on the trigeminal motoneurons, which may be important for understanding the mechanism of control of jaw movements, we investigated the distribution of vesicular glutamate transporter (VGLUT)1-immunopositive (+) and VGLUT2 + axon terminals (boutons) on the rat jaw-closing (JC) and jaw-opening (JO) motoneurons, and their morphological determinants of synaptic strength by retrograde tracing, electron microscopic immunohistochemistry, and quantitative ultrastructural analysis. We found that (1) the large majority of VGLUT + boutons on JC and JO motoneurons were VGLUT2+, (2) the density of VGLUT1 + boutons terminating on JC motoneurons was significantly higher than that on JO motoneurons, (3) the density of VGLUT1 + boutons terminating on non-primary dendrites of JC motoneurons was significantly higher than that on somata or primary dendrites, whereas the density of VGLUT2 + boutons was not significantly different between JC and JO motoneurons and among various compartments of the postsynaptic neurons, and (4) the bouton volume, mitochondrial volume, and active zone area of the VGLUT1 + boutons forming synapses on JC motoneurons were significantly bigger than those of VGLUT2 + boutons. These findings suggest that JC and JO motoneurons receive glutamatergic input primarily from VGLUT2-expressing intrinsic neurons (premotoneurons), and may be controlled differently by neurons in the trigeminal mesencephalic nucleus and by glutamatergic premotoneurons.

[Positional accuracy and quality assurance of Backup JAWs required for volumetric modulated arc therapy].

PubMed

Tatsumi, Daisaku; Nakada, Ryosei; Ienaga, Akinori; Yomoda, Akane; Inoue, Makoto; Ichida, Takao; Hosono, Masako

2012-01-01

The tolerance of the Backup diaphragm (Backup JAW) setting in Elekta linac was specified as 2 mm according to the AAPM TG-142 report. However, the tolerance and the quality assurance procedure for volumetric modulated arc therapy (VMAT) was not provided. This paper describes positional accuracy and quality assurance procedure of the Backup JAWs required for VMAT. It was found that a gap-width error of the Backup JAW by a sliding window test needed to be less than 1.5 mm for prostate VMAT delivery. It was also confirmed that the gap-widths had been maintained with an error of 0.2 mm during the past one year.

Analysis of feeding function and jaw stability in bedridden elderly.

PubMed

Tamura, Fumiyo; Mizukami, Miki; Ayano, Rika; Mukai, Yoshiharu

2002-01-01

The purpose of this study was to analyze the relationship between jaw stability and the feeding function of 53 bedridden elderly dysphagic patients. Investigations included a questionnaire on daily life activities and meals, oral examinations, functional tests for feeding ability, and assessments of feeding function during the meal. The results of intraoral examination of this patient population for jaw stability revealed that 34.0% of individuals had posterior support for occlusion regardless of whether they had natural teeth or dentures. Thus, the number classified as having mandibular stability (ST) was 18 and that with no mandibular stability (NST) was 35. In a Repetitive Saliva Swallowing Test (RSST), 83.3% of the NST group and 40.0% of the ST group were unable to swallow more than 3 times within 30 seconds. In a water swallowing test, 91.4% of the NST of group was unable to swallow 15 mL of water by a single swallow, while 40.0% of ST group was capable. The results suggest that jaw stabilization by occlusion with the posterior teeth or dental prosthetics is important to feeding function, particularly swallowing.

Evolution of Muscle Activity Patterns Driving Motions of the Jaw and Hyoid during Chewing in Gnathostomes

PubMed Central

Konow, Nicolai; Herrel, Anthony; Ross, Callum F.; Williams, Susan H.; German, Rebecca Z.; Sanford, Christopher P. J.; Gintof, Chris

2011-01-01

Although chewing has been suggested to be a basal gnathostome trait retained in most major vertebrate lineages, it has not been studied broadly and comparatively across vertebrates. To redress this imbalance, we recorded EMG from muscles powering anteroposterior movement of the hyoid, and dorsoventral movement of the mandibular jaw during chewing. We compared muscle activity patterns (MAP) during chewing in jawed vertebrate taxa belonging to unrelated groups of basal bony fishes and artiodactyl mammals. Our aim was to outline the evolution of coordination in MAP. Comparisons of activity in muscles of the jaw and hyoid that power chewing in closely related artiodactyls using cross-correlation analyses identified reorganizations of jaw and hyoid MAP between herbivores and omnivores. EMG data from basal bony fishes revealed a tighter coordination of jaw and hyoid MAP during chewing than seen in artiodactyls. Across this broad phylogenetic range, there have been major structural reorganizations, including a reduction of the bony hyoid suspension, which is robust in fishes, to the acquisition in a mammalian ancestor of a muscle sling suspending the hyoid. These changes appear to be reflected in a shift in chewing MAP that occurred in an unidentified anamniote stem-lineage. This shift matches observations that, when compared with fishes, the pattern of hyoid motion in tetrapods is reversed and also time-shifted relative to the pattern of jaw movement. PMID:21705368

Electromyogram biofeedback training for daytime clenching and its effect on sleep bruxism.

PubMed

Sato, M; Iizuka, T; Watanabe, A; Iwase, N; Otsuka, H; Terada, N; Fujisawa, M

2015-02-01

Bruxism contributes to the development of temporomandibular disorders as well as causes dental problems. Although it is an important issue in clinical dentistry, no treatment approaches have been proven effective. This study aimed to use electromyogram (EMG) biofeedback (BF) training to improve awake bruxism (AB) and examine its effect on sleep bruxism (SB). Twelve male participants (mean age, 26·8 ± 2·5 years) with subjective symptoms of AB or a diagnosis of SB were randomly divided into BF (n = 7) and control (CO, n = 5) groups to undergo 5-h daytime and night-time EMG measurements for three consecutive weeks. EMG electrodes were placed over the temporalis muscle on the habitual masticatory side. Those in the BF group underwent BF training to remind them of the occurrence of undesirable clenching activity when excessive EMG activity of certain burst duration was generated in week 2. Then, EMGs were recorded at week 3 as the post-BF test. Those in the CO group underwent EMG measurement without any EMG BF training throughout the study period. Although the number of tonic EMG events did not show statistically significant differences among weeks 1-3 in the CO group, events in weeks 2 and 3 decreased significantly compared with those in week 1, both daytime and night-time, in the BF group (P < 0·05, Scheffé's test). This study results suggest that EMG BF to improve AB tonic EMG events can also provide an effective approach to regulate SB tonic EMG events. © 2014 John Wiley & Sons Ltd.

New insights into dinosaur jaw muscle anatomy.

PubMed

Holliday, Casey M

2009-09-01

Jaw muscles are key components of the head and critical to testing hypotheses of soft-tissue homology, skull function, and evolution. Dinosaurs evolved an extraordinary diversity of cranial forms adapted to a variety of feeding behaviors. However, disparate evolutionary transformations in head shape and function among dinosaurs and their living relatives, birds and crocodylians, impair straightforward reconstructions of muscles, and other important cephalic soft tissues. This study presents the osteological correlates and inferred soft tissue anatomy of the jaw muscles and relevant neurovasculature in the temporal region of the dinosaur head. Hypotheses of jaw muscle homology were tested across a broad range archosaur and sauropsid taxa to more accurately infer muscle attachments in the adductor chambers of non-avian dinosaurs. Many dinosaurs likely possessed m. levator pterygoideus, a trait shared with lepidosaurs but not extant archosaurs. Several major clades of dinosaurs (e.g., Ornithopoda, Ceratopsidae, Sauropoda) eliminated the epipterygoid, thus impacting interpretations of m. pseudotemporalis profundus. M. pseudotemporalis superficialis most likely attached to the caudoventral surface of the laterosphenoid, a trait shared with extant archosaurs. Although mm. adductor mandibulae externus profundus and medialis likely attached to the caudal half of the dorsotemporal fossa and coronoid process, clear osteological correlates separating the individual bellies are rare. Most dinosaur clades possess osteological correlates indicative of a pterygoideus ventralis muscle that attaches to the lateral surface of the mandible, although the muscle may have extended as far as the jugal in some taxa (e.g., hadrosaurs, tyrannosaurs). The cranial and mandibular attachments of mm adductor mandibulae externus superficialis and adductor mandibulae posterior were consistent across all taxa studied. These new data greatly increase the interpretive resolution of head anatomy in

Jaw-Phonatory Coordination in Chronic Developmental Stuttering

ERIC Educational Resources Information Center

Loucks, Torrey M. J.; De Nil, Luc F.; Sasisekaran, Jayanthi

2007-01-01

A deficiency in sensorimotor integration in a person who stutters may be a factor in the pathophysiology of developmental stuttering. To test oral sensorimotor function in adults who stutter, we used a task that requires the coordination of a jaw-opening movement with phonation onset. The task was adapted from previous limb coordination studies,…

Radiolucent rim as a possible diagnostic aid for differentiating jaw lesions

PubMed Central

Mortazavi, Hamed; Rahmani, Somayeh; Jafari, Soudeh; Parvaei, Parvin

2015-01-01

In this study, we formulate a new proposal that complements previous classifications in order to assist dental practitioners in performing a differential diagnosis based on patients' radiographs. We used general search engines and specialized databases such as Google Scholar, PubMed, PubMed Central, MedLine Plus, Science Direct, Scopus, and well-recognized textbooks to find relevant studies by using keywords such as "jaw disease," "jaw lesions," "radiolucent rim," "radiolucent border," and "radiolucent halo." More than 200 articles were found, of which 70 were broadly relevant to the topic. We ultimately included 50 articles that were closely related to the topic of interest. When the relevant data were compiled, the following eight lesions were identified as having a radiolucent rim: periapical cemento-osseous dysplasia, focal cemento-osseous dysplasia, florid cemento-osseous dysplasia, cemento-ossifying fibroma, osteoid osteoma, osteoblastoma, odontoma, and cementoblastoma. We propose a novel subcategory, jaw lesions with a radiolucent rim, which includes eight entities. The implementation of this new category can help improve the diagnoses that dental practitioners make based on patients' radiographs. PMID:26730374

Development of the trigeminal motor neurons in parrots: implications for the role of nervous tissue in the evolution of jaw muscle morphology.

PubMed

Tokita, Masayoshi; Nakayama, Tomoki

2014-02-01

Vertebrates have succeeded to inhabit almost every ecological niche due in large part to the anatomical diversification of their jaw complex. As a component of the feeding apparatus, jaw muscles carry a vital role for determining the mode of feeding. Early patterning of the jaw muscles has been attributed to cranial neural crest-derived mesenchyme, however, much remains to be understood about the role of nonneural crest tissues in the evolution and diversification of jaw muscle morphology. In this study, we describe the development of trigeminal motor neurons in a parrot species with the uniquely shaped jaw muscles and compare its developmental pattern to that in the quail with the standard jaw muscles to uncover potential roles of nervous tissue in the evolution of vertebrate jaw muscles. In parrot embryogenesis, the motor axon bundles are detectable within the muscular tissue only after the basic shape of the muscular tissue has been established. This supports the view that nervous tissue does not primarily determine the spatial pattern of jaw muscles. In contrast, the trigeminal motor nucleus, which is composed of somata of neurons that innervate major jaw muscles, of parrot is more developed compared to quail, even in embryonic stage where no remarkable interspecific difference in both jaw muscle morphology and motor nerve branching pattern is recognized. Our data suggest that although nervous tissue may not have a large influence on initial patterning of jaw muscles, it may play an important role in subsequent growth and maintenance of muscular tissue and alterations in cranial nervous tissue development may underlie diversification of jaw muscle morphology. Copyright © 2013 Wiley Periodicals, Inc.

Realistic kinetic loading of the jaw system during single chewing cycles: a finite element study.

PubMed

Martinez Choy, S E; Lenz, J; Schweizerhof, K; Schmitter, M; Schindler, H J

2017-05-01

Although knowledge of short-range kinetic interactions between antagonistic teeth during mastication is of essential importance for ensuring interference-free fixed dental reconstructions, little information is available. In this study, the forces on and displacements of the teeth during kinetic molar biting simulating the power stroke of a chewing cycle were investigated by use of a finite-element model that included all the essential components of the human masticatory system, including an elastic food bolus. We hypothesised that the model can approximate the loading characteristics of the dentition found in previous experimental studies. The simulation was a transient analysis, that is, it considered the dynamic behaviour of the jaw. In particular, the reaction forces on the teeth and joints arose from contact, rather than nodal forces or constraints. To compute displacements of the teeth, the periodontal ligament (PDL) was modelled by use of an Ogden material model calibrated on the basis of results obtained in previous experiments. During the initial holding phase of the power stroke, bite forces were aligned with the roots of the molars until substantial deformation of the bolus occurred. The forces tilted the molars in the bucco-lingual and mesio-distal directions, but as the intrusive force increased the teeth returned to their initial configuration. The Ogden material model used for the PDL enabled accurate prediction of the displacements observed in experimental tests. In conclusion, the comprehensive kinetic finite element model reproduced the kinematic and loading characteristics of previous experimental investigations. © 2017 John Wiley & Sons Ltd.

The earliest herbivorous marine reptile and its remarkable jaw apparatus.

PubMed

Chun, Li; Rieppel, Olivier; Long, Cheng; Fraser, Nicholas C

2016-05-01

Newly discovered fossils of the Middle Triassic reptile Atopodentatus unicus call for a radical reassessment of its feeding behavior. The skull displays a pronounced hammerhead shape that was hitherto unknown. The long, straight anterior edges of both upper and lower jaws were lined with batteries of chisel-shaped teeth, whereas the remaining parts of the jaw rami supported densely packed needle-shaped teeth forming a mesh. The evidence indicates a novel feeding mechanism wherein the chisel-shaped teeth were used to scrape algae off the substrate, and the plant matter that was loosened was filtered from the water column through the more posteriorly positioned tooth mesh. This is the oldest record of herbivory within marine reptiles.

The earliest herbivorous marine reptile and its remarkable jaw apparatus

PubMed Central

Chun, Li; Rieppel, Olivier; Long, Cheng; Fraser, Nicholas C.

2016-01-01

Newly discovered fossils of the Middle Triassic reptile Atopodentatus unicus call for a radical reassessment of its feeding behavior. The skull displays a pronounced hammerhead shape that was hitherto unknown. The long, straight anterior edges of both upper and lower jaws were lined with batteries of chisel-shaped teeth, whereas the remaining parts of the jaw rami supported densely packed needle-shaped teeth forming a mesh. The evidence indicates a novel feeding mechanism wherein the chisel-shaped teeth were used to scrape algae off the substrate, and the plant matter that was loosened was filtered from the water column through the more posteriorly positioned tooth mesh. This is the oldest record of herbivory within marine reptiles. PMID:27386529

Toolmarks made by lathe chuck jaws.

PubMed

Finkelstein, Nir; Aronson, Ayal; Tsach, Tsadok

2017-06-01

This paper presents a forensic method to evidentially tie a workpiece with a specific lathe. Examining using this method can prove or exclude a connection between the two. The importance of this method is mostly due to the growing trend among lawbreakers of manufacturing improvised firearm parts using machining processes. This method is based on comparing jaw impressions made by the chuck on a workpiece. Copyright © 2017 Elsevier B.V. All rights reserved.

Dosimetric effect on pediatric conformal treatment plans using dynamic jaw with Tomotherapy HDA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Eun Young, E-mail: eyhan@uams.edu; Kim, Dong-Wook; Zhang, Xin

It is important to minimize the radiation dose delivered to healthy tissues in pediatric cancer treatment because of the risk of secondary malignancies. Tomotherapy HDA provides a dynamic jaw (DJ) delivery mode that creates a sharper penumbra at the craniocaudal ends of a target in addition to a fixed jaw (FJ) delivery mode. The purpose of this study was to evaluate its dosimetric effect on the pediatric cancer cases. We included 6 pediatric cases in this study. The dose profiles and plan statistics—target dose conformity, uniformity, organ-at-risk (OAR) mean dose, beam-on time, and integral dose—were compared for each case. Consequently,more » the target dose coverage and uniformity were similar for different jaw settings. The OAR dose sparing depended on its relative location to the target and disease sites. For example, in the head and neck cancer cases, the brain stem dose using DJ 2.5 was reduced by more than two-fold (2.4 Gy vs. 6.3 Gy) than that obtained with FJ 2.5. The integral dose with DJ 2.5 decreased by more than 9% compared with that with FJ 2.5. Thus, using dynamic jaw in pediatric cases could be critical to reduce a probability of a secondary malignancy.« less

Brain activity associated with memory and cognitive function during jaw-tapping movement in healthy subjects using functional magnetic resonance imaging.

PubMed

Cho, Seung-Yeon; Shin, Ae-Sook; Na, Byung-Jo; Jahng, Geon-Ho; Park, Seong-Uk; Jung, Woo-Sang; Moon, Sang-Kwan; Park, Jung-Mi

2013-06-01

To determine whether jaw-tapping movement, a classically described as an indication of personal well-being and mental health, stimulates the memory and the cognitive regions of the brain and is associated with improved brain performance. Twelve healthy right-handed female subjects completed the study. Each patient performed a jaw-tapping task and an n-back task during functional magnetic resonance imaging (fMRI). The subjects were trained to carry out the jaw-tapping movement at home twice a day for 4 weeks. The fMRI was repeated when they returned. During the first and second jaw-tapping session, both sides of precentral gyrus and the right middle frontal gyrus (BA 6) were activated. And during the second session of the jaw-tapping task, parts of frontal lobe and temporal lobe related to memory function were more activated. In addition, the total percent task accuracy in n-back task significantly increased after 4 weeks of jawtapping movement. After jaw-tapping training for 4 weeks, brain areas related to memory showed significantly increased blood oxygen level dependent signals. Jaw-tapping movement might be a useful exercise for stimulating the memory and cognitive regions of the brain.

[Bruxism, temporo-mandibular dysfunction and botulinum toxin].

PubMed

Chikhani, L; Dichamp, J

2003-07-01

Tooth grinding and tooth clenching are unvoluntary mainly nocturnal habits that result in an hypertrophy of masseter and temporalis muscles with an unbalance between opening and closing muscles of the jaw and lead to an alteration of mandibular condyles movements and to hyper pressure in the temporo-mandibular joints (TMJ) which can generate severe pain. Intra muscular injections of botulinum toxin permit to restablish the balance between closing and opening muscles, to relieve pain, to treat masseteric hypertrophy with improvement of face outline and to recover a normal cinetic of temporo-mandibular joints. Moreover, botulinum toxin injections permit to quit habits of tooth grinding and clenching and one single session of injections is curative for 2/3 of the patients. There are no side effects apart from slight diffusion to superficial muscles of the face resulting in a "fixed" smile for about 6 to 8 weeks. So injections of botulinum toxin in masseter and temporalis muscles are an efficient treatment of bruxism and TMJ dysfunction, cheap with no lasting side effect.

Sella size and jaw bases - Is there a correlation???

PubMed

Neha; Mogra, Subraya; Shetty, Vorvady Surendra; Shetty, Siddarth

2016-01-01

Sella turcica is an important cephalometric structure and attempts have been made in the past to correlate its dimensions to the malocclusion. However, no study has so far compared the size of sella to the jaw bases that determine the type of malocclusion. The present study was undertaken to find out any such correlation if it exists. Lateral cephalograms of 110 adults consisting of 40 Class I, 40 Class II, and 30 Class III patients were assessed for the measurement of sella length, width, height, and area. The maxillary length, mandibular ramus height, and body length were also measured. The sella dimensions were compared among three malocclusion types by one-way ANOVA. Pearson correlation was calculated between the jaw size and sella dimensions. Furthermore, the ratio of jaw base lengths and sella area were calculated. Mean sella length, width and area were found to be greatest in Class III, followed by Class I and least in Class II though the results were not statistically significant. 3 out of 4 measured dimensions of sella, correlated significantly with mandibular ramus and body length each. However, only one dimension of sella showed significant correlation with maxilla. The mandibular ramus and body length show a nearly constant ratio to sella area (0.83-0.85, 0.64-0.65, respectively) in all the three malocclusions. Thus, mandible has a definite and better correlation to the size of sella turcica.

Scaling and Accommodation of Jaw Adductor Muscles in Canidae

PubMed Central

Kemp, Graham J.; Jeffery, Nathan

2016-01-01

ABSTRACT The masticatory apparatus amongst closely related carnivoran species raises intriguing questions about the interplay between allometry, function, and phylogeny in defining interspecific variations of cranial morphology. Here we describe the gross structure of the jaw adductor muscles of several species of canid, and then examine how the muscles are scaled across the range of body sizes, phylogenies, and trophic groups. We also consider how the muscles are accommodated on the skull, and how this is influenced by differences of endocranial size. Data were collected for a suite of morphological metrics, including body mass, endocranial volume, and muscle masses and we used geometric morphometric shape analysis to reveal associated form changes. We find that all jaw adductor muscles scale isometrically against body mass, regardless of phylogeny or trophic group, but that endocranial volume scales with negative allometry against body mass. These findings suggest that head shape is partly influenced by the need to house isometrically scaling muscles on a neurocranium scaling with negative allometry. Principal component analysis suggests that skull shape changes, such as the relatively wide zygomatic arches and large sagittal crests seen in species with higher body masses, allow the skull to accommodate a relative enlargement of the jaw adductors compared with the endocranium. Anat Rec, 299:951–966, 2016. © 2016 The Authors The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology Published by Wiley Periodicals, Inc. PMID:27103346

Ameloblastomatous Change in Radicular Cyst of The Jaw in a Nigerian Population.

PubMed

Omoregie, F O; Sede, M A; Ojo, A M

2015-06-01

To determine the incidence, age, gender, jaw-sites and subtypes of radicular cyst, and to determine the incidence of ameloblastomatous change in radicular cyst in a Nigerian population. A 10-year retrospective analysis of all diagnosed orofacial lesions in the Department of Oral Pathology and Medicine, University of Benin Teaching Hospital, Benin City, Nigeria. From the 785 diagnosed orofacial lesions within the study period; there were 54 (6.9%) cases of radicular cysts of the jaws. The peak age group was the 3(rd) decade (n=23, 42.6%) with a mean age of 31 ± 1.7 years. There were 29 (53.7%) males and 25 (46.3%) females, giving a ratio of 1.2:1. The mandible was the commonest jaw-site (n=32, 59.3%). There were 12 (22.2%) cases of periapical cyst which were significantly associated with anterior maxillary site (n=8, 14.8%) [p=0.001]. Seven (13.0%) cases of cystic ameloblastoma were diagnosed among the radicular cysts, with a predilection of the lesions for 3(rd) and 4(th) decades of life (n=6, 11.1%), and posterior mandible (n=5, 9.3%). This study showed a low incidence of radicular cyst of the jaw among orofacial lesions and a relatively higher incidence of ameloblastomatous change in radicular cyst compared to previous reports. Immuno-histochemical examination is recommended to differentiate radicular cyst with ameloblastomatous-like change from cystic ameloblastoma arising from radicular cyst.

The evolution of jaw protrusion mechanics is tightly coupled to bentho-pelagic divergence in damselfishes (Pomacentridae).

PubMed

Cooper, W James; Carter, Casey B; Conith, Andrew J; Rice, Aaron N; Westneat, Mark W

2017-02-15

Most species-rich lineages of aquatic organisms have undergone divergence between forms that feed from the substrate (benthic feeding) and forms that feed from the water column (pelagic feeding). Changes in trophic niche are frequently accompanied by changes in skull mechanics, and multiple fish lineages have evolved highly specialized biomechanical configurations that allow them to protrude their upper jaws toward the prey during feeding. Damselfishes (family Pomacentridae) are an example of a species-rich lineage with multiple trophic morphologies and feeding ecologies. We sought to determine whether bentho-pelagic divergence in the damselfishes is tightly coupled to changes in jaw protrusion ability. Using high-speed video recordings and kinematic analysis, we examined feeding performance in 10 species that include three examples of convergence on herbivory, three examples of convergence on omnivory and two examples of convergence on planktivory. We also utilized morphometrics to characterize the feeding morphology of an additional 40 species that represent all 29 damselfish genera. Comparative phylogenetic analyses were then used to examine the evolution of trophic morphology and biomechanical performance. We find that pelagic-feeding damselfishes (planktivores) are strongly differentiated from extensively benthic-feeding species (omnivores and herbivores) by their jaw protrusion ability, upper jaw morphology and the functional integration of upper jaw protrusion with lower jaw abduction. Most aspects of cranial form and function that separate these two ecological groups have evolved in correlation with each other and the evolution of the functional morphology of feeding in damselfishes has involved repeated convergence in form, function and ecology. © 2017. Published by The Company of Biologists Ltd.

Jaw Dysfunction Is Associated with Neck Disability and Muscle Tenderness in Subjects with and without Chronic Temporomandibular Disorders

PubMed Central

Silveira, A.; Gadotti, I. C.; Armijo-Olivo, S.; Biasotto-Gonzalez, D. A.; Magee, D.

2015-01-01

Purpose. Tender points in the neck are common in patients with temporomandibular disorders (TMD). However, the correlation among neck disability, jaw dysfunction, and muscle tenderness in subjects with TMD still needs further investigation. This study investigated the correlation among neck disability, jaw dysfunction, and muscle tenderness in subjects with and without chronic TMD. Participants. Forty females between 19 and 49 years old were included in this study. There were 20 healthy controls and 20 subjects who had chronic TMD and neck disability. Methods. Subjects completed the neck disability index and the limitations of daily functions in TMD questionnaires. Tenderness of the masticatory and cervical muscles was measured using an algometer. Results. The correlation between jaw disability and neck disability was significantly high (r = 0.915, P < 0.05). The correlation between level of muscle tenderness in the masticatory and cervical muscles with jaw dysfunction and neck disability showed fair to moderate correlations (r = 0.32–0.65). Conclusion. High levels of muscle tenderness in upper trapezius and temporalis muscles correlated with high levels of jaw and neck dysfunction. Moreover, high levels of neck disability correlated with high levels of jaw disability. These findings emphasize the importance of considering the neck and its structures when evaluating and treating patients with TMD. PMID:25883963

Jaw dysfunction is associated with neck disability and muscle tenderness in subjects with and without chronic temporomandibular disorders.

PubMed

Silveira, A; Gadotti, I C; Armijo-Olivo, S; Biasotto-Gonzalez, D A; Magee, D

2015-01-01

Tender points in the neck are common in patients with temporomandibular disorders (TMD). However, the correlation among neck disability, jaw dysfunction, and muscle tenderness in subjects with TMD still needs further investigation. This study investigated the correlation among neck disability, jaw dysfunction, and muscle tenderness in subjects with and without chronic TMD. Participants. Forty females between 19 and 49 years old were included in this study. There were 20 healthy controls and 20 subjects who had chronic TMD and neck disability. Subjects completed the neck disability index and the limitations of daily functions in TMD questionnaires. Tenderness of the masticatory and cervical muscles was measured using an algometer. The correlation between jaw disability and neck disability was significantly high (r = 0.915, P < 0.05). The correlation between level of muscle tenderness in the masticatory and cervical muscles with jaw dysfunction and neck disability showed fair to moderate correlations (r = 0.32-0.65). High levels of muscle tenderness in upper trapezius and temporalis muscles correlated with high levels of jaw and neck dysfunction. Moreover, high levels of neck disability correlated with high levels of jaw disability. These findings emphasize the importance of considering the neck and its structures when evaluating and treating patients with TMD.

Assessment of the increased calcification of the jaw bone with CT-Scan after dental implant placement

PubMed Central

2011-01-01

Purpose This study was performed to evaluate the changes of jaw bone density around the dental implant after placement using computed tomography scan (CT-Scan). Materials and Methods This retrospective study consisted of 30 patients who had lost 1 posterior tooth in maxilla or mandible and installed dental implant. The patients took CT-Scan before and after implant placement. Hounsfield Unit (HU) was measured around the implants and evaluated the difference of HU before and after implant installation. Results The mean HU of jaw bone was 542.436 HU and 764.9 HU before and after implant placement, respectively (p<0.05). The means HUs for male were 632.3 HU and 932.2 HU and those for female 478.2 HU and 645.5 HU before and after implant placement, respectively (p<0.05). Also, the jaw bone with lower density needed longer period for implant procedure and the increased change of HU of jaw bone was less in the cases which needed longer period for osseointegration. Conclusion CT-Scan could be used to assess the change of bone density around dental implants. Bone density around dental implant was increased after placement. The increased rate of bone density could be determined by the quality of jaw bone before implant placement. PMID:21977476

Assessment of the increased calcification of the jaw bone with CT-Scan after dental implant placement.

PubMed

Yunus, Barunawaty

2011-06-01

This study was performed to evaluate the changes of jaw bone density around the dental implant after placement using computed tomography scan (CT-Scan). This retrospective study consisted of 30 patients who had lost 1 posterior tooth in maxilla or mandible and installed dental implant. The patients took CT-Scan before and after implant placement. Hounsfield Unit (HU) was measured around the implants and evaluated the difference of HU before and after implant installation. The mean HU of jaw bone was 542.436 HU and 764.9 HU before and after implant placement, respectively (p<0.05). The means HUs for male were 632.3 HU and 932.2 HU and those for female 478.2 HU and 645.5 HU before and after implant placement, respectively (p<0.05). Also, the jaw bone with lower density needed longer period for implant procedure and the increased change of HU of jaw bone was less in the cases which needed longer period for osseointegration. CT-Scan could be used to assess the change of bone density around dental implants. Bone density around dental implant was increased after placement. The increased rate of bone density could be determined by the quality of jaw bone before implant placement.

X-ray computed tomography library of shark anatomy and lower jaw surface models.

PubMed

Kamminga, Pepijn; De Bruin, Paul W; Geleijns, Jacob; Brazeau, Martin D

2017-04-11

The cranial diversity of sharks reflects disparate biomechanical adaptations to feeding. In order to be able to investigate and better understand the ecomorphology of extant shark feeding systems, we created a x-ray computed tomography (CT) library of shark cranial anatomy with three-dimensional (3D) lower jaw reconstructions. This is used to examine and quantify lower jaw disparity in extant shark species in a separate study. The library is divided in a dataset comprised of medical CT scans of 122 sharks (Selachimorpha, Chondrichthyes) representing 73 extant species, including digitized morphology of entire shark specimens. This CT dataset and additional data provided by other researchers was used to reconstruct a second dataset containing 3D models of the left lower jaw for 153 individuals representing 94 extant shark species. These datasets form an extensive anatomical record of shark skeletal anatomy, necessary for comparative morphological, biomechanical, ecological and phylogenetic studies.

Modulation of jaw muscle spindle afferent activity following intramuscular injections with hypertonic saline.

PubMed

Ro, J Y; Capra, N F

2001-05-01

Transient noxious chemical stimulation of small diameter muscle afferents modulates jaw movement-related responses of caudal brainstem neurons. While it is likely that the effect is mediated from the spindle afferents in the mesencephalic nucleus (Vmes) via the caudally projecting Probst's tract, the mechanisms of pain induced modulations of jaw muscle spindle afferents is not known. In the present study, we tested the hypothesis that jaw muscle nociceptors gain access to muscle spindle afferents in the same muscle via central mechanisms and alter their sensitivity. Thirty-five neurons recorded from the Vmes were characterized as muscle spindle afferents based on their responses to passive jaw movements, muscle palpation, and electrical stimulation of the masseter nerve. Each cell was tested by injecting a small volume (250 microl) of either 5% hypertonic and/or isotonic saline into the receptor-bearing muscle. Twenty-nine units were tested with 5% hypertonic saline, of which 79% (23/29) showed significant modulation of mean firing rates (MFRs) during one or more phases of ramp-and-hold movements. Among the muscle spindle primary-like units (n = 12), MFRs of 4 units were facilitated, five reduced, two showed mixed responses and one unchanged. In secondary-like units (n = 17), MFRs of 9 were facilitated, three reduced and five unchanged. Thirteen units were tested with isotonic saline, of which 77% showed no significant changes of MFRs. Further analysis revealed that the hypertonic saline not only affected the overall output of muscle spindle afferents, but also increased the variability of firing and altered the relationship between afferent signal and muscle length. These results demonstrated that activation of muscle nociceptors significantly affects proprioceptive properties of jaw muscle spindles via central neural mechanisms. The changes can have deleterious effects on oral motor function as well as kinesthetic sensibility.

Dosimetric effect on pediatric conformal treatment plans using dynamic jaw with Tomotherapy HDA.

PubMed

Han, Eun Young; Kim, Dong-Wook; Zhang, Xin; Penagaricano, Jose; Liang, Xiaoying; Hardee, Matthew; Morrill, Steve; Ratanatharathorn, Vaneerat

2015-01-01

It is important to minimize the radiation dose delivered to healthy tissues in pediatric cancer treatment because of the risk of secondary malignancies. Tomotherapy HDA provides a dynamic jaw (DJ) delivery mode that creates a sharper penumbra at the craniocaudal ends of a target in addition to a fixed jaw (FJ) delivery mode. The purpose of this study was to evaluate its dosimetric effect on the pediatric cancer cases. We included 6 pediatric cases in this study. The dose profiles and plan statistics—target dose conformity, uniformity, organ-at-risk (OAR) mean dose, beam-on time, and integral dose—were compared for each case. Consequently, the target dose coverage and uniformity were similar for different jaw settings. The OAR dose sparing depended on its relative location to the target and disease sites. For example, in the head and neck cancer cases, the brain stem dose using DJ 2.5 was reduced by more than two-fold (2.4 Gy vs. 6.3 Gy) than that obtained with FJ 2.5. The integral dose with DJ 2.5 decreased by more than 9% compared with that with FJ 2.5. Thus, using dynamic jaw in pediatric cases could be critical to reduce a probability of a secondary malignancy. Copyright © 2015 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

A jaw calibration method to provide a homogeneous dose distribution in the matching region when using a monoisocentric beam split technique.

PubMed

Cenizo, E; García-Pareja, S; Galán, P; Bodineau, C; Caudepón, F; Casado, F J

2011-05-01

Asymmetric collimators are currently available in most of linear accelerators. They involve a lot of clinical improvements, such as the monoisocentric beam split technique that is more and more used in many external radiotherapy treatments. The tolerance established for each independent jaw positioning is 1 mm. Within this tolerance, a gap or overlap of the collimators up to 2 mm can occur in the half beams matching region, causing dose heterogeneities up to 40%. In order to solve this dosimetric problem, we propose an accurate jaw calibration method based on the Monte Carlo modeling of linac photon beams. Simulating different jaw misalignments, the dose distribution occurring in the matching region for each particular configuration is precisely known, so we can relate the misalignment of the jaws with the maximum heterogeneity produced. From experimental measurements using film dosimetry, and taking into account Monte Carlo results, we obtain the actual misalignment of each jaw. By direct inspection of the readings of the potentiometers that control the position of the jaws, high precision correction can be performed, adjusting the obtained misalignments. In the linac studied, the dose heterogeneity in the junction performed with X jaws (those farther from the source), and 6 MV photon beam was initially over 12%, although each jaw was within the tolerance in position. After jaw calibration, the heterogeneity was reduced to below 3%. With this method, we are able to reduce the positioning accuracy to 0.2 mm. Consequently, the dose distribution in the junction of abutted fields is highly smoothed, achieving the maximum dose heterogeneity to be less than 3%.

Adaptive phenotypic plasticity in the Midas cichlid fish pharyngeal jaw and its relevance in adaptive radiation

PubMed Central

2011-01-01

Background Phenotypic evolution and its role in the diversification of organisms is a central topic in evolutionary biology. A neglected factor during the modern evolutionary synthesis, adaptive phenotypic plasticity, more recently attracted the attention of many evolutionary biologists and is now recognized as an important ingredient in both population persistence and diversification. The traits and directions in which an ancestral source population displays phenotypic plasticity might partly determine the trajectories in morphospace, which are accessible for an adaptive radiation, starting from the colonization of a novel environment. In the case of repeated colonizations of similar environments from the same source population this "flexible stem" hypothesis predicts similar phenotypes to arise in repeated subsequent radiations. The Midas Cichlid (Amphilophus spp.) in Nicaragua has radiated in parallel in several crater-lakes seeded by populations originating from the Nicaraguan Great Lakes. Here, we tested phenotypic plasticity in the pharyngeal jaw of Midas Cichlids. The pharyngeal jaw apparatus of cichlids, a second set of jaws functionally decoupled from the oral ones, is known to mediate ecological specialization and often differs strongly between sister-species. Results We performed a common garden experiment raising three groups of Midas cichlids on food differing in hardness and calcium content. Analyzing the lower pharyngeal jaw-bones we find significant differences between diet groups qualitatively resembling the differences found between specialized species. Observed differences in pharyngeal jaw expression between groups were attributable to the diet's mechanical resistance, whereas surplus calcium in the diet was not found to be of importance. Conclusions The pharyngeal jaw apparatus of Midas Cichlids can be expressed plastically if stimulated mechanically during feeding. Since this trait is commonly differentiated - among other traits - between

Adaptive phenotypic plasticity in the Midas cichlid fish pharyngeal jaw and its relevance in adaptive radiation.

PubMed

Muschick, Moritz; Barluenga, Marta; Salzburger, Walter; Meyer, Axel

2011-04-30

Phenotypic evolution and its role in the diversification of organisms is a central topic in evolutionary biology. A neglected factor during the modern evolutionary synthesis, adaptive phenotypic plasticity, more recently attracted the attention of many evolutionary biologists and is now recognized as an important ingredient in both population persistence and diversification. The traits and directions in which an ancestral source population displays phenotypic plasticity might partly determine the trajectories in morphospace, which are accessible for an adaptive radiation, starting from the colonization of a novel environment. In the case of repeated colonizations of similar environments from the same source population this "flexible stem" hypothesis predicts similar phenotypes to arise in repeated subsequent radiations. The Midas Cichlid (Amphilophus spp.) in Nicaragua has radiated in parallel in several crater-lakes seeded by populations originating from the Nicaraguan Great Lakes. Here, we tested phenotypic plasticity in the pharyngeal jaw of Midas Cichlids. The pharyngeal jaw apparatus of cichlids, a second set of jaws functionally decoupled from the oral ones, is known to mediate ecological specialization and often differs strongly between sister-species. We performed a common garden experiment raising three groups of Midas cichlids on food differing in hardness and calcium content. Analyzing the lower pharyngeal jaw-bones we find significant differences between diet groups qualitatively resembling the differences found between specialized species. Observed differences in pharyngeal jaw expression between groups were attributable to the diet's mechanical resistance, whereas surplus calcium in the diet was not found to be of importance. The pharyngeal jaw apparatus of Midas Cichlids can be expressed plastically if stimulated mechanically during feeding. Since this trait is commonly differentiated--among other traits--between Midas Cichlid species, its plasticity

Processing system of jaws tomograms for pathology identification and surgical guide modeling

NASA Astrophysics Data System (ADS)

Putrik, M. B.; Lavrentyeva, Yu. E.; Ivanov, V. Yu.

2015-11-01

The aim of the study is to create an image processing system, which allows dentists to find pathological resorption and to build surgical guide surface automatically. X-rays images of jaws from cone beam tomography or spiral computed tomography are the initial data for processing. One patient's examination always includes up to 600 images (or tomograms), that's why the development of processing system for fast automation search of pathologies is necessary. X-rays images can be useful not for only illness diagnostic but for treatment planning too. We have studied the case of dental implantation - for successful surgical manipulations surgical guides are used. We have created a processing system that automatically builds jaw and teeth boundaries on the x-ray image. After this step, obtained teeth boundaries used for surgical guide surface modeling and jaw boundaries limit the area for further pathologies search. Criterion for the presence of pathological resorption zones inside the limited area is based on statistical investigation. After described actions, it is possible to manufacture surgical guide using 3D printer and apply it in surgical operation.

A piezoelectric film-based intrasplint detection method for bruxism.

PubMed

Takeuchi, H; Ikeda, T; Clark, G T

2001-08-01

An accurate, easy-to-use, long-term method other than EMG is needed to monitor bruxism. This article presents pilot data on the reproducibility, validity, and utility of an intrasplint piezoelectric film method. Simulated bruxism behaviors (steady-state and rhythmic clenching, grinding, and tapping) in 5 subjects were recorded with the use of both masseter EMG and an intrasplint piezoelectric film method. Correlation coefficients calculated for simulated bruxism event duration with the use of a masseter EMG or an intrasplint piezoelectric film method were 0.99 for tapping and steady-state clenching, 0.96 for rhythmic clenching, and 0.79 for grinding. Piezoelectric film has its limitations and does not faithfully capture sustained force magnitudes. However, for the target behaviors associated with bruxism (tooth grinding, clenching, and tapping), it appears to faithfully reproduce above-baseline events with durations statistically indistinguishable from those recorded with masseter EMG. Masseter EMG was poorest at detecting a simulated side-to-side grinding behavior.

Basal jawed vertebrate phylogeny inferred from multiple nuclear DNA-coded genes

PubMed Central

Kikugawa, Kanae; Katoh, Kazutaka; Kuraku, Shigehiro; Sakurai, Hiroshi; Ishida, Osamu; Iwabe, Naoyuki; Miyata, Takashi

2004-01-01

Background Phylogenetic analyses of jawed vertebrates based on mitochondrial sequences often result in confusing inferences which are obviously inconsistent with generally accepted trees. In particular, in a hypothesis by Rasmussen and Arnason based on mitochondrial trees, cartilaginous fishes have a terminal position in a paraphyletic cluster of bony fishes. No previous analysis based on nuclear DNA-coded genes could significantly reject the mitochondrial trees of jawed vertebrates. Results We have cloned and sequenced seven nuclear DNA-coded genes from 13 vertebrate species. These sequences, together with sequences available from databases including 13 jawed vertebrates from eight major groups (cartilaginous fishes, bichir, chondrosteans, gar, bowfin, teleost fishes, lungfishes and tetrapods) and an outgroup (a cyclostome and a lancelet), have been subjected to phylogenetic analyses based on the maximum likelihood method. Conclusion Cartilaginous fishes have been inferred to be basal to other jawed vertebrates, which is consistent with the generally accepted view. The minimum log-likelihood difference between the maximum likelihood tree and trees not supporting the basal position of cartilaginous fishes is 18.3 ± 13.1. The hypothesis by Rasmussen and Arnason has been significantly rejected with the minimum log-likelihood difference of 123 ± 23.3. Our tree has also shown that living holosteans, comprising bowfin and gar, form a monophyletic group which is the sister group to teleost fishes. This is consistent with a formerly prevalent view of vertebrate classification, although inconsistent with both of the current morphology-based and mitochondrial sequence-based trees. Furthermore, the bichir has been shown to be the basal ray-finned fish. Tetrapods and lungfish have formed a monophyletic cluster in the tree inferred from the concatenated alignment, being consistent with the currently prevalent view. It also remains possible that tetrapods are more closely

Malagasy cichlids differentially limit impacts of body shape evolution on oral jaw functional morphology.

PubMed

Martinez, Christopher M; Sparks, John S

2017-09-01

Patterns of trait covariation, such as integration and modularity, are vital factors that influence the evolution of vertebrate body plans. In functional systems, decoupling of morphological modules buffers functional change in one trait by reducing correlated variation with another. However, for complex morphologies with many-to-one mapping of form to function (MTOM), resistance to functional change may also be achieved by constraining morphological variation within a functionally stable region of morphospace. For this research, we used geometric morphometrics to evaluate the evolution of body shape and its relationship with jaw functional morphology in two independent radiations of endemic Malagasy cichlid (Teleostei: Cichlidae). Our results suggested that the two subfamilies used different strategies to mitigate impacts of body shape variation on a metric of jaw function, maxillary kinematic transmission (MKT): (1) modularity between cranial and postcranial morphologies, and (2) integration of body and jaw evolution, with jaw morphologies varying in a manner that limits change in MKT. This research shows that, unlike modularity, MTOM allows traits to retain strong evolutionary covariation while still reducing impacts on functionality. These results suggest that MTOM, and its influence on the evolution of correlated traits, is likely much more widespread than is currently understood. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

[A man with pain in his upper jaw].

PubMed

Jaspers, Gijs; van Gool, Lex

2011-01-01

A 66-year-old man came to the hospital with pain in the frontal left side of his upper jaw. Pressure along the left nostril could evoke a sharp pain, which radiated upwards. The patient had already consulted several specialists. After extended clinical and radiological investigation a mesiodens was found that gave pressure on the nasopalatine nerve.

Effects of the closing speed of stapler jaws on bovine pancreases.

PubMed

Chikamoto, Akira; Hashimoto, Daisuke; Ikuta, Yoshiaki; Tsuji, Akira; Abe, Shinya; Hayashi, Hiromitsu; Imai, Katsunori; Nitta, Hidetoshi; Ishiko, Takatoshi; Watanabe, Masayuki; Beppu, Toru; Baba, Hideo

2014-01-01

The division of the pancreatic parenchyma using a stapler is important in pancreatic surgery, especially for laparoscopic surgery. However, this procedure has not yet been standardized. We analyzed the effects of the closing speed of stapler jaws using bovine pancreases for each method. Furthermore, we assigned 10 min to the slow compression method, 5 min to the medium-fast compression method, and 30 s to the rapid compression (RC) method. The time allotted to holding (3 min) and dividing (30 s) was equal under each testing situation. We found that the RC method showed a high-pressure tolerance compared with the other two groups (rapid, 126 ± 49.0 mmHg; medium-fast, 55.5 ± 25.8 mmHg; slow, 45.0 ± 15.7 mmHg; p < 0.01), although the histological findings of the cut end were similar. The histological findings of the pancreatic capsule and parenchyma after the compression by staple jaws without firing also were similar. RC may provide an advantage as measured by pressure tolerance. A small series of distal pancreatectomy with a stapler that compares the speed of different stapler jaw closing times is required to prove the feasibility of these results after the confirmation of the advantages of the RC method under various settings.

[Trigeminal motor paralysis and dislocation of the temporo-mandibular joints].

PubMed

Ohkawa, S; Yoshida, T; Ohsumi, Y; Tabuchi, M

1996-07-01

A 64-year-old woman with diabetes mellitus was admitted to our hospital with left hemiparesis of sudden onset. A brain MRI demonstrated a cerebral infarction in the ventral part of the right lower pons. When left hemiparesis worsened, she had dislocation of the temporo-mandibular joints repeatedly. Then, her lower jaw deviated to the right when she opened her mouth. Also, there was decreased contraction of the right masseter when she clenched her teeth. These findings suggest that there was trigeminal motor paralysis on the right side resulting from involvement of the intrapontine trigeminal motor nerve. She has no history of dislocation of the temporo-mandibular joints. An X-ray film showed that the temporo-mandibular joints were intact. Thus, it is possible that deviation of the lower jaw was the cause of this dislocation. We suspect that dislocation of the temporo-mandibular joints may occur as a complication of unilateral trigeminal motor paralysis. This has not been reported to our knowledge.

Effect of pinching-evoked pain on jaw-stretch reflexes and exteroceptive suppression periods in healthy subjects.

PubMed

Biasiotta, A; Peddireddy, A; Wang, K; Romaniello, A; Frati, A; Svensson, P; Arendt-Nielsen, L

2007-10-01

To investigate the influence of conditioning cutaneous nociceptive inputs by a new "pinch" model on the jaw-stretch reflex and the exteroceptive suppression periods (ES1 and ES2) in jaw muscles. The jaw-stretch reflex was evoked with the use of a custom-made muscle stretcher and electrical stimuli were used to evoke an early and late exteroceptive suppression period (ES1 and ES2) in the jaw-closing muscles. Electromyographic (EMG) activity was recorded bilaterally from the masseter and temporalis muscles. These brainstem reflexes were recorded in 19 healthy men (28.8+/-1.1 years) during three different conditions: one painful clip applied to the earlobe; one painful clip applied to the nostril, and four painful clips applied simultaneously to the earlobe, nostril, eyebrow, and lower lip. Pain intensity induced by the application of the clips was scored continuously by the subjects on a 100mm visual analogue scale (VAS). The highest VAS pain scores were evoked by placement of four clips (79+/-0.5mm). There was no significant modulation of the jaw-stretch reflex (ANOVAs: P=0.929), the ES1 (P=0.298) or ES2 (P=0.082) in any of the three painful conditions. Intense and tonic cutaneous pain could be elicited by this new "pinch" pain model; however, there was no significant modulation on either excitatory or inhibitory brainstem reflex responses. The novel observation that high-intensity pinch stimuli applied to the craniofacial region fail to modulate two different brainstem reflexes is in contrast to other experimental pain studies documented facilitation of the jaw-stretch reflexes or inhibition of exteroceptive suppression periods. The clinical implication of the present findings is that only some craniofacial pain conditions could be expected to show perturbation of the brainstem reflex responses.

A new 4-dimensional imaging system for jaw tracking.

PubMed

Lauren, Mark

2014-01-01

A non-invasive 4D imaging system that produces high resolution time-based 3D surface data has been developed to capture jaw motion. Fluorescent microspheres are brushed onto both tooth and soft-tissue areas of the upper and lower arches to be imaged. An extraoral hand-held imaging device, operated about 12 cm from the mouth, captures a time-based set of perspective image triplets of the patch areas. Each triplet, containing both upper and lower arch data, is converted to a high-resolution 3D point mesh using photogrammetry, providing the instantaneous relative jaw position. Eight 3D positions per second are captured. Using one of the 3D frames as a reference, a 4D model can be constructed to describe the incremental free body motion of the mandible. The surface data produced by this system can be registered to conventional 3D models of the dentition, allowing them to be animated. Applications include integration into prosthetic CAD and CBCT data.

Jaw Dysfunction Related to Pterygoid and Masseter Muscle Dosimetry After Radiation Therapy in Children and Young Adults With Head-and-Neck Sarcomas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krasin, Matthew J., E-mail: matthew.krasin@stjude.org; Wiese, Kristin M.; Spunt, Sheri L.

Purpose: To investigate the relationship between jaw function, patient and treatment variables, and radiation dosimetry of the mandibular muscles and joints in children and young adults receiving radiation for soft-tissue and bone sarcomas. Methods and Materials: Twenty-four pediatric and young adult patients with head-and-neck sarcomas were treated on an institutional review board-approved prospective study of focal radiation therapy for local tumor control. Serial jaw depression measurements were related to radiation dosimetry delivered to the medial and lateral pterygoid muscles, masseter muscles, and temporomandibular joints to generate mathematical models of jaw function. Results: Baseline jaw depression was only influenced by themore » degree of surgical resection. In the first 12 weeks from initiation of radiation, surgical procedures greater than a biopsy, administration of cyclophosphamide containing chemotherapy regimes, and large gross tumor volumes adversely affected jaw depression. Increasing dose to the pterygoid and masseter muscles above 40 Gy predicted loss of jaw function over the full course of follow-up. Conclusions: Clinical and treatment factors are related to initial and subsequent jaw dysfunction. Understanding these complex interactions and the affect of specific radiation doses may help reduce the risk for jaw dysfunction in future children and young adults undergoing radiation therapy for the management of soft-tissue and bone sarcomas.« less

Kinematic Features of Jaw and Lips Distinguish Symptomatic From Presymptomatic Stages of Bulbar Decline in Amyotrophic Lateral Sclerosis.

PubMed

Bandini, Andrea; Green, Jordan R; Wang, Jun; Campbell, Thomas F; Zinman, Lorne; Yunusova, Yana

2018-05-17

The goals of this study were to (a) classify speech movements of patients with amyotrophic lateral sclerosis (ALS) in presymptomatic and symptomatic phases of bulbar function decline relying solely on kinematic features of lips and jaw and (b) identify the most important measures that detect the transition between early and late bulbar changes. One hundred ninety-two recordings obtained from 64 patients with ALS were considered for the analysis. Feature selection and classification algorithms were used to analyze lip and jaw movements recorded with Optotrak Certus (Northern Digital Inc.) during a sentence task. A feature set, which included 35 measures of movement range, velocity, acceleration, jerk, and area measures of lips and jaw, was used to classify sessions according to the speaking rate into presymptomatic (> 160 words per minute) and symptomatic (< 160 words per minute) groups. Presymptomatic and symptomatic phases of bulbar decline were distinguished with high accuracy (87%), relying only on lip and jaw movements. The best features that allowed detecting the differences between early and later bulbar stages included cumulative path of lower lip and jaw, peak values of velocity, acceleration, and jerk of lower lip and jaw. The results established a relationship between facial kinematics and bulbar function decline in ALS. Considering that facial movements can be recorded by means of novel inexpensive and easy-to-use, video-based methods, this work supports the development of an automatic system for facial movement analysis to help clinicians in tracking the disease progression in ALS.

Experimental muscle pain produces central modulation of proprioceptive signals arising from jaw muscle spindles.

PubMed

Capra, N F; Ro, J Y

2000-05-01

The aim of the present study was to investigate the effects of intramuscular injection with hypertonic saline, a well-established experimental model for muscle pain, on central processing of proprioceptive input from jaw muscle spindle afferents. Fifty-seven cells were recorded from the medial edge of the subnucleus interpolaris (Vi) and the adjacent parvicellular reticular formation from 11 adult cats. These cells were characterized as central units receiving jaw muscle spindle input based on their responses to electrical stimulation of the masseter nerve, muscle palpation and jaw stretch. Forty-five cells, which were successfully tested with 5% hypertonic saline, were categorized as either dynamic-static (DS) (n=25) or static (S) (n=20) neurons based on their responses to different speeds and amplitudes of jaw movement. Seventy-six percent of the cells tested with an ipsilateral injection of hypertonic saline showed a significant modulation of mean firing rates (MFRs) during opening and/or holding phases. The most remarkable saline-induced change was a significant reduction of MFR during the hold phase in S units (100%, 18/18 modulated). Sixty-nine percent of the DS units (11/16 modulated) also showed significant changes in MFRs limited to the hold phase. However, in the DS neurons, the MFRs increased in seven units and decreased in four units. Finally, five DS neurons showed significant changes of MFRs during both opening and holding phases. Injections of isotonic saline into the ipsilateral masseter muscle had little effect, but hypertonic saline injections made into the contralateral masseter muscle produced similar results to ipsilateral injections with hypertonic saline. These results unequivocally demonstrate that intramuscular injection with an algesic substance, sufficient to produce muscle pain, produces significant changes in the proprioceptive properties of the jaw movement-related neurons. Potential mechanisms involved in saline-induced changes in the

SU-F-T-307: Peripheral Dose Comparison Between Static and Dynamic Jaw Tracking On a High Definition MLC System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perez-Andujar, A; Cheung, J; Chuang, C

Purpose: To investigate the effect of dynamic and static jaw tracking on patient peripheral doses. Materials and Methods: A patient plan with a large sacral metastasis (volume 800cm3, prescription 600cGyx5) was selected for this study. The plan was created using 2-field RapidArc with jaw tracking enabled (Eclipse, V11.0.31). These fields were then exported and edited in MATLAB with static jaw positions using the control point with the largest field size for each respective arc, but preserving the optimized leaf sequences for delivery. These fields were imported back into Eclipse for dose calculation and comparison and copied to a Rando phantommore » for delivery analysis. Points were chosen in the phantom at depth and on the phantom surface at locations outside the primary radiation field, at distances of 12cm, 20cm, and 30cm from the isocenter. Measurements were acquired with OSLDs placed at these positions in the phantom with both the dynamic and static jaw deliveries for comparison. Surface measurements included an additional 1cm bolus over the OSLDs to ensure electron equilibrium. Results: The static jaw deliveries resulted in cumulative jaw-defined field sizes of 17.3% and 17.4% greater area than the dynamic jaw deliveries for each arc. The static jaw plan resulted in very small differences in calculated dose in the treatment planning system ranging from 0–16cGy. The measured dose differences were larger than calculated, but the differences in absolute dose were small. The measured dose differences at depth (surface) between the two deliveries showed an increase for the static jaw delivery of 2.2%(11.4%), 15.6%(20.0%), and 12.7%(12.7%) for distances of 12cm, 20cm, and 30cm, respectively. Eclipse calculates a difference of 0–3.1% for all of these points. The largest absolute dose difference between all points was 6.2cGy. Conclusion: While we demonstrated larger than expected differences in peripheral dose, the absolute dose differences were small.« less

Processing system of jaws tomograms for pathology identification and surgical guide modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Putrik, M. B., E-mail: pmb-88@mail.ru; Ivanov, V. Yu.; Lavrentyeva, Yu. E.

The aim of the study is to create an image processing system, which allows dentists to find pathological resorption and to build surgical guide surface automatically. X-rays images of jaws from cone beam tomography or spiral computed tomography are the initial data for processing. One patient’s examination always includes up to 600 images (or tomograms), that’s why the development of processing system for fast automation search of pathologies is necessary. X-rays images can be useful not for only illness diagnostic but for treatment planning too. We have studied the case of dental implantation – for successful surgical manipulations surgical guidesmore » are used. We have created a processing system that automatically builds jaw and teeth boundaries on the x-ray image. After this step, obtained teeth boundaries used for surgical guide surface modeling and jaw boundaries limit the area for further pathologies search. Criterion for the presence of pathological resorption zones inside the limited area is based on statistical investigation. After described actions, it is possible to manufacture surgical guide using 3D printer and apply it in surgical operation.« less

Measurement of jaw motion: the proposal of a simple and accurate method.

PubMed

Pinheiro, A P; Pereira, A A; Andrade, A O; Bellomo, D

2011-01-01

The analysis of jaw movements has long been used as a measure for clinical diagnosis and assessment. A number of strategies are available for monitoring the trajectory; however most of these strategies make use of expensive tools, which are often not available to many clinics in the world. In this context, this research proposes the development of a new tool capable of quantifying the movements of opening/closing, protrusion and laterotrusion of the mandible. These movements are important for the clinical evaluation of both the temporomandibular function and muscles involved in mastication. The proposed system, unlike current commercial systems, employs a low-cost video camera and a computer program, which is used for reconstructing the trajectory of a reflective marker that is fixed on the jaw. In order to illustrate the application of the devised tool a clinical trial was carried out, investigating jaw movements of 10 subjects. The results obtained in this study were compatible with those found in the literature with the advantage of using a low-cost, simple, non-invasive and flexible solution customized for the practical needs of clinics. The average error of the system was less than 1.0%.

Jaw symptoms and signs and the connection to cranial cervical symptoms and post-traumatic stress during the first year after a whiplash trauma.

PubMed

Severinsson, Yvonne; Bunketorp, Olle; Wenneberg, Bengt

2010-01-01

To estimate the prevalence of jaw symptoms and signs during the first year after a neck sprain in a car collision. Further, to determine their relationships to the localisation and grade of the initial neck symptoms and signs, headache, post-traumatic stress and crash characteristics. One hundred and forty-six adult subjects and crash characteristics were prospectively investigated in an in-depth study during 1997-2001. Head, neck, and jaw symptoms and signs were recorded within 5 weeks and after 1 year. Acute post-traumatic stress was estimated with the Impact of Event Scale-Revised (IES-R). Jaw symptoms were initially reported by three men (5%) and three women (4%), and subsequently developed in eight women (10%) during the following year. Jaw signs were noted initially in 53 subjects (37%) and in 28 subjects (24%) after 1 year, without difference between sexes, and more often after low-speed impacts. Headache in females, cranial cervical symptoms, pronounced neck problems, post-traumatic stress and whiplash-associated disorders (WAD) grade II-III after rear-end impacts were related to jaw signs during the acute phase. After 1 year, jaw signs were related to residual neck problems, headache and post-traumatic stress. Jaw symptoms are seldom reported during the acute phase after a whiplash trauma. Women more often than men develop jaw symptoms during the first year. Jaw symptoms and signs may develop also after low-speed impacts, especially after rear-end collisions. Jaw symptoms and signs should be observed after whiplash trauma, especially in those with headache, pronounced neck problems, cranial neck symptoms and post-traumatic stress.

Three-dimensional reconstruction of teeth and jaws based on segmentation of CT images using watershed transformation.

PubMed

Naumovich, S S; Naumovich, S A; Goncharenko, V G

2015-01-01

The objective of the present study was the development and clinical testing of a three-dimensional (3D) reconstruction method of teeth and a bone tissue of the jaw on the basis of CT images of the maxillofacial region. 3D reconstruction was performed using the specially designed original software based on watershed transformation. Computed tomograms in digital imaging and communications in medicine format obtained on multispiral CT and CBCT scanners were used for creation of 3D models of teeth and the jaws. The processing algorithm is realized in the stepwise threshold image segmentation with the placement of markers in the mode of a multiplanar projection in areas relating to the teeth and a bone tissue. The developed software initially creates coarse 3D models of the entire dentition and the jaw. Then, certain procedures specify the model of the jaw and cut the dentition into separate teeth. The proper selection of the segmentation threshold is very important for CBCT images having a low contrast and high noise level. The developed semi-automatic algorithm of multispiral and cone beam computed tomogram processing allows 3D models of teeth to be created separating them from a bone tissue of the jaws. The software is easy to install in a dentist's workplace, has an intuitive interface and takes little time in processing. The obtained 3D models can be used for solving a wide range of scientific and clinical tasks.

Asymmetric activation of motor cortex controlling human anterior digastric muscles during speech and target-directed jaw movements.

PubMed

Sowman, Paul F; Flavel, Stanley C; McShane, Christie L; Sakuma, Shigemitsu; Miles, Timothy S; Nordstrom, Michael A

2009-07-01

Like most of the cranial muscles involved in speech, the trigeminally innervated anterior digastric muscles are controlled by descending corticobulbar projections from the primary motor cortex (M1) of each hemisphere. We hypothesized that changes in corticobulbar M1 excitability during speech production would show a hemispheric asymmetry favoring the left side, which is the dominant hemisphere for language processing in most strongly right handed subjects. Fifteen volunteers aged 24.5+/-5.3 (SD) yr participated. All subjects were strongly right handed as reported by questionnaire. A surface electromyograph (EMG) was recorded bilaterally from digastrics and jaw movement detected by an accelerometer attached to a lower incisor. Focal transcranial magnetic stimulation (TMS) was used to assess corticomotor excitability of the digastric representation in M1 of both hemispheres during four tasks: 1) static isometric contraction of digastrics; 2) speaking a single word; 3) visually guided, nonspeech jaw movement that matched the jaw kinematics recorded during task 2; and 4) reciting a sentence. Background EMG was well matched in all tasks and jaw kinematics were similar around the time of the TMS pulse for tasks 2-4. TMS resting thresholds and digastric muscle-evoked potential (MEP) size during isometric contraction did not differ for TMS over left versus right M1. MEPs elicited by TMS over left, but not right M1 increased in size during speech and nonspeech jaw movement compared with isometric contraction. We conclude that left corticobulbar M1 is preferentially engaged for descending control of digastric muscles during speech and the performance of a rapid jaw movement to match a target kinematic profile.

Evaluation of jaw and neck muscle activities while chewing using EMG-EMG transfer function and EMG-EMG coherence function analyses in healthy subjects.

PubMed

Ishii, Tomohiro; Narita, Noriyuki; Endo, Hiroshi

2016-06-01

This study aims to quantitatively clarify the physiological features in rhythmically coordinated jaw and neck muscle EMG activities while chewing gum using EMG-EMG transfer function and EMG-EMG coherence function analyses in 20 healthy subjects. The chewing side masseter muscle EMG signal was used as the reference signal, while the other jaw (non-chewing side masseter muscle, bilateral anterior temporal muscles, and bilateral anterior digastric muscles) and neck muscle (bilateral sternocleidomastoid muscles) EMG signals were used as the examined signals in EMG-EMG transfer function and EMG-EMG coherence function analyses. Chewing-related jaw and neck muscle activities were aggregated in the first peak of the power spectrum in rhythmic chewing. The gain in the peak frequency represented the power relationships between jaw and neck muscle activities during rhythmic chewing. The phase in the peak frequency represented the temporal relationships between the jaw and neck muscle activities, while the non-chewing side neck muscle presented a broad range of distributions across jaw closing and opening phases. Coherence in the peak frequency represented the synergistic features in bilateral jaw closing muscles and chewing side neck muscle activities. The coherence and phase in non-chewing side neck muscle activities exhibited a significant negative correlation. From above, the bilateral coordination between the jaw and neck muscle activities is estimated while chewing when the non-chewing side neck muscle is synchronously activated with the jaw closing muscles, while the unilateral coordination is estimated when the non-chewing side neck muscle is irregularly activated in the jaw opening phase. Thus, the occurrence of bilateral or unilateral coordinated features in the jaw and neck muscle activities may correspond to the phase characteristics in the non-chewing side neck muscle activities during rhythmical chewing. Considering these novel findings in healthy subjects, EMG

Evolution of the vertebrate jaw: comparative embryology and molecular developmental biology reveal the factors behind evolutionary novelty

PubMed Central

Kuratani, Shigeru

2004-01-01

It is generally believed that the jaw arose through the simple transformation of an ancestral rostral gill arch. The gnathostome jaw differentiates from Hox-free crest cells in the mandibular arch, and this is also apparent in the lamprey. The basic Hox code, including the Hox-free default state in the mandibular arch, may have been present in the common ancestor, and jaw patterning appears to have been secondarily constructed in the gnathostomes. The distribution of the cephalic neural crest cells is similar in the early pharyngula of gnathostomes and lampreys, but different cell subsets form the oral apparatus in each group through epithelial–mesenchymal interactions: and this heterotopy is likely to have been an important evolutionary change that permitted jaw differentiation. This theory implies that the premandibular crest cells differentiate into the upper lip, or the dorsal subdivision of the oral apparatus in the lamprey, whereas the equivalent cell population forms the trabecula of the skull base in gnathostomes. Because the gnathostome oral apparatus is derived exclusively from the mandibular arch, the concepts ‘oral’ and ‘mandibular’ must be dissociated. The ‘lamprey trabecula’ develops from mandibular mesoderm, and is not homologous with the gnathostome trabecula, which develops from premandibular crest cells. Thus the jaw evolved as an evolutionary novelty through tissue rearrangements and topographical changes in tissue interactions. PMID:15575882

Intraosseous mucoepidermoid carcinoma: a review of the diagnostic imaging features of four jaw cases.

PubMed

Chan, K C; Pharoah, M; Lee, L; Weinreb, I; Perez-Ordonez, B

2013-01-01

The purpose of this case series is to present the common features of intraosseous mucoepidermoid carcinoma (IMC) of the jaws in plain film and CT imaging. Two oral and maxillofacial radiologists reviewed and characterized the common features of four biopsy-proven cases of IMC in the jaws in plain film and CT imaging obtained from the files of the Department of Oral Radiology, Faculty of Dentistry, University of Toronto, Toronto, Canada. The common features are a well-defined sclerotic periphery, the presence of internal amorphous sclerotic bone and numerous small loculations, lack of septae bordering many of the loculations, and expansion and perforation of the outer cortical plate with extension into surrounding soft tissue. Other characteristics include tooth displacement and root resorption. The four cases of IMC reviewed have common imaging characteristics. All cases share some diagnostic imaging features with other multilocular-appearing entities of the jaws. However, the presence of amorphous sclerotic bone and malignant characteristics can be useful in the differential diagnosis.

Annual reversible plasticity of feeding structures: cyclical changes of jaw allometry in a sea urchin

PubMed Central

Ebert, Thomas A.; Hernández, José Carlos; Clemente, Sabrina

2014-01-01

A wide variety of organisms show morphologically plastic responses to environmental stressors but in general these changes are not reversible. Though less common, reversible morphological structures are shown by a range of species in response to changes in predators, competitors or food. Theoretical analysis indicates that reversible plasticity increases fitness if organisms are long-lived relative to the frequency of changes in the stressor and morphological changes are rapid. Many sea urchin species show differences in the sizes of jaws (demi-pyramids) of the feeding apparatus, Aristotle's lantern, relative to overall body size, and these differences have been correlated with available food. The question addressed here is whether reversible changes of relative jaw size occur in the field as available food changes with season. Monthly samples of the North American Pacific coast sea urchin Strongylocentrotus purpuratus were collected from Gregory Point on the Oregon (USA) coast and showed an annual cycle of relative jaw size together with a linear trend from 2007 to 2009. Strongylocentrotus purpuratus is a long-lived species and under field conditions individuals experience multiple episodes of changes in food resources both seasonally and from year to year. Their rapid and reversible jaw plasticity fits well with theoretical expectations. PMID:24500161

The effect of food bolus location on jaw movement smoothness and masticatory efficiency.

PubMed

Molenaar, W N B; Gezelle Meerburg, P J; Luraschi, J; Whittle, T; Schimmel, M; Lobbezoo, F; Peck, C C; Murray, G M; Minami, I

2012-09-01

Masticatory efficiency in individuals with extensive tooth loss has been widely discussed. However, little is known about jaw movement smoothness during chewing and the effect of differences in food bolus location on movement smoothness and masticatory efficiency. The aim of this study was to determine whether experimental differences in food bolus location (anterior versus posterior) had an effect on masticatory efficiency and jaw movement smoothness. Jaw movement smoothness was evaluated by measuring jerk-cost (calculated from acceleration) with an accelerometer that was attached to the skin of the mentum of 10 asymptomatic subjects, and acceleration was recorded during chewing on two-colour chewing gum, which was used to assessed masticatory efficiency. Chewing was performed under two conditions: posterior chewing (chewing on molars and premolars only) and anterior chewing (chewing on canine and first premolar teeth only). Jerk-cost and masticatory efficiency (calculated as the ratio of unmixed azure colour to the total area of gum, the unmixed fraction) were compared between anterior and posterior chewing with the Wilcoxon signed rank test (two-tailed). Subjects chewed significantly less efficiently during anterior chewing than during posterior chewing (P = 0·0051). There was no significant difference in jerk-cost between anterior and posterior conditions in the opening phase (P = 0·25), or closing phase (P = 0·42). This is the first characterisation of the effect of food bolus location on jaw movement smoothness at the same time as recording masticatory efficiency. The data suggest that anterior chewing decreases masticatory efficiency, but does not influence jerk-cost. © 2012 Blackwell Publishing Ltd.

SU-E-T-346: Effect of Jaw Position On Dose to Critical Structures in 3-D Conformal Radiotherapy Treatment of Pancreatic Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paudel, N; Han, E; Liang, X

Purpose: Three-dimensional conformal therapy remains a valid and widely used modality for pancreatic radiotherapy treatment. It usually meets dose constraints on critical structures. However, careful positioning of collimation jaws can reduce dose to the critical structures. Here we investigate the dosimetric effect of jaw position in MLC-based 3-D conformal treatment planning on critical structures. Methods: We retrospectively selected seven pancreatic cancer patients treated with 3-D conformal radiotherapy. We started with treatment plans (Varian Truebeam LINAC, Eclipse TPS, AAA, 18MV) having both x and y jaws aligned with the farthest extent of the block outline (8mm around PTV). Then we subsequentlymore » moved either both x-jaws or all x and y jaws outwards upto 3 cm in 1 cm increments and investigated their effect on average and maximum dose to neighboring critical structures keeping the same coverage to treatment volume. Results: Lateral displacement of both x-jaws by 1cm each increased kidney and spleen mean dose by as much as 1.7% and 1.3% respectively and superior inferior displacement increased liver, right kidney, stomach and spleen dose by as much as 2.1%, 2%, 5.2% and 1.6% respectively. Displacement of all x and y-jaws away by 1cm increased the mean dose to liver, right kidney, left kidney, bowels, cord, stomach and spleen by as much as 4.9%, 5.9%, 2.1%, 2.8%, 7.4%, 10.4% and 4.2% respectively. Percentage increase in mean dose due to 2 and 3cm jaw displacement increased almost linearly with the displaced distance. Changes in maximum dose were much smaller (mostly negligible) than the changes in mean dose. Conclusion: Collimation jaw position affects dose mostly to critical structures adjacent to it. Though treatment plans with MLCs conforming the block margin usually meet dose constraints to critical structures, keeping jaws all the way in, to the edge of the block reduces dose to the critical structures during radiation treatment.« less

Embryology of the lamprey and evolution of the vertebrate jaw: insights from molecular and developmental perspectives.

PubMed Central

Kuratani, S; Nobusada, Y; Horigome, N; Shigetani, Y

2001-01-01

Evolution of the vertebrate jaw has been reviewed and discussed based on the developmental pattern of the Japanese marine lamprey, Lampetra japonica. Though it never forms a jointed jaw apparatus, the L. japonica embryo exhibits the typical embryonic structure as well as the conserved regulatory gene expression patterns of vertebrates. The lamprey therefore shares the phylotype of vertebrates, the conserved embryonic pattern that appears at pharyngula stage, rather than representing an intermediate evolutionary state. Both gnathostomes and lampreys exhibit a tripartite configuration of the rostral-most crest-derived ectomesenchyme, each part occupying an anatomically equivalent site. Differentiated oral structure becomes apparent in post-pharyngula development. Due to the solid nasohypophyseal plate, the post-optic ectomesenchyme of the lamprey fails to grow rostromedially to form the medial nasal septum as in gnathostomes, but forms the upper lip instead. The gnathostome jaw may thus have arisen through a process of ontogenetic repatterning, in which a heterotopic shift of mesenchyme-epithelial relationships would have been involved. Further identification of shifts in tissue interaction and expression of regulatory genes are necessary to describe the evolution of the jaw fully from the standpoint of evolutionary developmental biology. PMID:11604127

Root canal therapy for the prevention of osteonecrosis of the jaws: an evidence-based clinical update.

PubMed

Kyrgidis, Athanassios; Arora, Amit; Lyroudia, Kleoniki; Antoniades, Konstantinos

2010-12-01

Osteonecrosis of the jaws is an adverse effect of bone preservation treatment. There is a sufficient body of evidence to associate osteonecrosis of the jaws development with dental extractions and trauma caused from ill-fitting dentures. In this review, we critically appraise available evidence about the clinical efficacy of root canal therapy in patients receiving bisphosphonates.We review a series of theories to explain why endodontic treatment is a safe clinical intervention to prevent osteonecrosis of the jaws in patients receiving bisphosphonates. Root canal therapy could postpone or even eradicate the need for dental extractions of carious teeth in patients on bisphosphonates who may develop osteonecrosis of the jaws. Patients receiving bisphosphonates should be offered the full range of preventive care to reduce their risk to both dental caries and periodontal disease, so that the need for both endodontic therapy and dental extractions will be reduced. Implementing such a strategy would require both practitioner and patient education through the combined efforts of medical and dental societies. Such an approach is justified, as the risk of compromising the oral health of patients on bisphosphonates undertaking endodontic treatment is negligible compared with the benefit from avoiding dental extractions.

Jaw motion during gum-chewing in children with primary dentition.

PubMed

Kubota, Naoko; Hayasaki, Haruaki; Saitoh, Issei; Iwase, Yoko; Maruyama, Tomoaki; Inada, Emi; Hasegawa, Hiroko; Yamada, Chiaki; Takemoto, Yoshihiko; Matsumoto, Yuko; Yamasaki, Youichi

2010-01-01

This study was undertaken to characterize jaw motion during mastication in children with primary dentition and to compare jaw motion with that in adults. The means and the variances of the traditional parameters for the chewing cycle, i.e., duration, excursive ranges and 3-D distances of travel at the lower incisor, molars and condyles were analyzed and compared in 23 children and 25 female adults. The duration of opening in children was significantly shorter than that of adults. Significant differences between children and adults were observed in lateral and vertical excursion of the incisor, lateral excursion at the molars, and vertical excursion at the condyles. Many of these measurements had larger between-subject and between-cycle variances in children than adults, suggesting that chewing motion in children has not yet matured. The results of this study indicate that chewing motion in children is different from that of adults.

2,3,7,8-Tetrachlorodibenzo-p-dioxin toxicity in the zebrafish embryo: altered regional blood flow and impaired lower jaw development.

PubMed

Teraoka, Hiroki; Dong, Wu; Ogawa, Shuji; Tsukiyama, Shusaku; Okuhara, Yuji; Niiyama, Masayoshi; Ueno, Naoto; Peterson, Richard E; Hiraga, Takeo

2002-02-01

The effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure on regional red blood cell (RBC) perfusion rate, as an index of blood flow, and lower jaw development were investigated quantitatively in zebrafish embryos (Danio rerio) during early development. As revealed by observation of live embryos and alcian-blue staining, TCDD retarded lower jaw development in a concentration-dependent manner with only a minor inhibitory effect on total body length. Both inhibitory effects were significant as early as 60 h postfertilization (hpf), at which time the area of goosecoid (gsc) mRNA expression was clearly reduced in the lower jaw. To examine effects of TCDD on RBC perfusion rate, time-lapse recording was performed using a digital video camera attached to a light microscope. TCDD did not show marked effects on RBC perfusion rate until 72 hpf, when vessel-specific effects emerged. TCDD severely inhibited RBC perfusion rate in intersegmental arteries of the trunk, but only modestly and slightly inhibited RBC perfusion rate in certain vessels of the head such as the central arteries and optic vein. Conversely, at both 72 and 84 hpf, TCDD significantly increased RBC perfusion rate in the hypobranchial artery branching to the lower jaw primordia, and then reduced it at 96 hpf. RBC perfusion rate in all vessels examined in TCDD-exposed embryos was inhibited at 96 hpf. The zebrafish aryl hydrocarbon receptor 2 (zfAhR2) mRNA was strongly expressed in the lower jaw primordia at 48 hpf, and expression of this transcript was augmented by TCDD treatment. Thus, TCDD exposure of the zebrafish embryo has a disruptive effect on local circulation and lower jaw cartilage growth. Initially, TCDD may act directly on the lower jaw primordia to impair lower jaw development. Reductions in hypobranchial RBC perfusion rate occurred well after the initial retardation in lower jaw development had become apparent, and may contribute further to the effect.

Determination of capacity of single-toggle jaw crusher, taking into account parameters of kinematics of its working mechanism

NASA Astrophysics Data System (ADS)

Golikov, N. S.; Timofeev, I. P.

2018-05-01

Efficiency increase of jaw crushers makes the foundation of rational kinematics and stiffening of the elements of the machine possible. Foundation of rational kinematics includes establishment of connection between operation mode parameters of the crusher and its technical characteristics. The main purpose of this research is just to establish such a connection. Therefore this article shows analytical procedure of getting connection between operation mode parameters of the crusher and its capacity. Theoretical, empirical and semi-empirical methods of capacity determination of a single-toggle jaw crusher are given, taking into account physico-mechanical properties of crushed material and kinematics of the working mechanism. When developing a mathematical model, the method of closed vector polygons by V. A. Zinoviev was used. The expressions obtained in the article give an opportunity to solve important scientific and technical problems, connected with finding the rational kinematics of the jaw crusher mechanism, carrying out a comparative assessment of different crushers and giving the recommendations about updating the available jaw crushers.

15. NORTH ELEVATION OF UPPER ORE BIN, CHUTE, AND JAW ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. NORTH ELEVATION OF UPPER ORE BIN, CHUTE, AND JAW CRUSHER, LOOKING SOUTH FROM END OF CONVEYOR PLATFORM. NOTICE THE THREE ORE BIN CONTROL DOORS, CORRESPONDING TO SEPARATE COMPARTMENTS OF THE BIN. - Skidoo Mine, Park Route 38 (Skidoo Road), Death Valley Junction, Inyo County, CA

Bite force measurement based on fiber Bragg grating sensor

NASA Astrophysics Data System (ADS)

Padma, Srivani; Umesh, Sharath; Asokan, Sundarrajan; Srinivas, Talabattula

2017-10-01

The maximum level of voluntary bite force, which results from the combined action of muscle of mastication, joints, and teeth, i.e., craniomandibular structure, is considered as one of the major indicators for the functional state of the masticatory system. Measurement of voluntary bite force provides useful data for the jaw muscle function and activity along with assessment of prosthetics. This study proposes an in vivo methodology for the dynamic measurement of bite force employing a fiber Bragg grating (FBG) sensor known as bite force measurement device (BFMD). The BFMD developed is a noninvasive intraoral device, which transduces the bite force exerted at the occlusal surface into strain variations on a metal plate. These strain variations are acquired by the FBG sensor bonded over it. The BFMD developed facilitates adjustment of the distance between the biting platform, which is essential to capture the maximum voluntary bite force at three different positions of teeth, namely incisor, premolar, and molar sites. The clinically relevant bite forces are measured at incisor, molar, and premolar position and have been compared against each other. Furthermore, the bite forces measured with all subjects are segregated according to gender and also compared against each other.

[Florid cemento-osseous dysplasia of the jaws].

PubMed

Benazzou, S; Boulaadas, M; El Ayoubi, A; Nazih, N; Essakalli, L; Kzadri, M

2011-06-01

Florid cemento-osseous dysplasia is a benign and rare tumor of the jaws. It is more commonly seen in middle-aged black women. Most cases are asymptomatic and are found during routine radiographic examination. We report two complicated cases of florid cemento-osseous dysplasia, one with facial deformity and the other with chronic osteitis. The diagnosis of florid cemento-osseous dysplasia is based on clinical and radiological features. The lesions are commonly bilateral and symmetrical. Copyright © 2011. Published by Elsevier Masson SAS.

Pediatric Odontogenic Cysts of the Jaws.

PubMed

Arce, Kevin; Streff, Christopher S; Ettinger, Kyle S

2016-02-01

Odontogenic cysts represent a common form of pathology of the jaws, and the natural history, clinicopathologic findings, and appropriate management strategies are important to the oral and maxillofacial surgeon. Odontogenic cysts in the pediatric populations are important pathologic entities given their potential impact on the growth and development of the maxillofacial complex. Inappropriate management strategies can severely affect the form and function of the growing child. Categorizing pediatric odontogenic cysts into inflammatory or developmental causes provides a convenient way of conceptualizing these various entities and helps facilitate the appropriate diagnosis and the subsequent management. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of Mandibular Retrusive Deviation on Prefrontal Cortex Activation: A Functional Near-Infrared Spectroscopy Study

PubMed Central

Otsuka, Takero; Yamasaki, Ryuichi; Shimazaki, Tateshi; Sasaguri, Kenichi; Kawata, Toshitsugu

2015-01-01

The objective of this study was to evaluate occlusal condition by assessing brain activity in the prefrontal cortex, which is associated with emotion. Functional near-infrared spectroscopy (fNIRS) was used to detect changes in cerebral blood flow in the prefrontal cortex of 12 healthy volunteers. The malocclusion model was a custom-made splint that forced the mandible into retrusion. A splint with no modification was used as a control. The cortical activation during clenching was compared between the retrusive position condition and the control condition. A visual analog scale score for discomfort was also obtained during clenching and used to evaluate the interaction between fNIRS data and psychiatric changes. Activation of the prefrontal cortex was significantly greater during clenching in the mandibular retrusive condition than during clenching in the control condition. Furthermore, Spearman rank-correlation coefficient revealed a parallel relation between prefrontal cortex activation and visual analog scale score for discomfort. These results indicate that fNIRS can be used to objectively evaluate the occlusal condition by evaluating activity in the prefrontal cortex. PMID:26075235

Effects of mandibular retrusive deviation on prefrontal cortex activation: a functional near-infrared spectroscopy study.

PubMed

Otsuka, Takero; Yamasaki, Ryuichi; Shimazaki, Tateshi; Yoshino, Fumihiko; Sasaguri, Kenichi; Kawata, Toshitsugu

2015-01-01

The objective of this study was to evaluate occlusal condition by assessing brain activity in the prefrontal cortex, which is associated with emotion. Functional near-infrared spectroscopy (fNIRS) was used to detect changes in cerebral blood flow in the prefrontal cortex of 12 healthy volunteers. The malocclusion model was a custom-made splint that forced the mandible into retrusion. A splint with no modification was used as a control. The cortical activation during clenching was compared between the retrusive position condition and the control condition. A visual analog scale score for discomfort was also obtained during clenching and used to evaluate the interaction between fNIRS data and psychiatric changes. Activation of the prefrontal cortex was significantly greater during clenching in the mandibular retrusive condition than during clenching in the control condition. Furthermore, Spearman rank-correlation coefficient revealed a parallel relation between prefrontal cortex activation and visual analog scale score for discomfort. These results indicate that fNIRS can be used to objectively evaluate the occlusal condition by evaluating activity in the prefrontal cortex.

A Retrospective Analysis of Radiographic Jaw Findings in Young Women; Prevalence and Predictors

PubMed Central

El Khateeb, Sara M.; Abu-Hammad, Osama; Fadel, Hani; Dar-Odeh, Najla

2017-01-01

Aims and Objectives: To determine the prevalence and types of jaw pathologic findings as detected in panoramic radiographs of a sample of young women attending a teaching hospital in Al Madinah Al Munawarah, Saudi Arabia, and to determine the most important factors that predict the occurrence of jaw pathologic findings. Materials and Methods: The electronic clinical files of a representative sample of female patients who attended the outpatient dental clinics were retrieved. Patients were aged 18 to 25 years. Types of pathologic radiographic jaw findings and their prevalence were determined through screening of panoramic radiographs. Data were analyzed using the statistical analysis software [SPSS version 21 (IBM Corp.)]. Multiple linear regression was used to explore the significance of some types of dental lesions as predictor variables for the occurrence of jaw pathologic findings. Results: A total of 190 patients (mean age, 22.4 ± 2.46 years) were included in the study. Periapical lesions, retained roots, and alveolar bone loss were detected in 53.6%, 24.8%, and 17.4% of the participants, respectively. Other odontogenic abnormalities such as supernumerary and impacted teeth (6.4% and 33.7%, respectively) were also detected. Patients' age was found to be a good predictor for alveolar bone loss and number of periapical lesions (P ≤ 0.05). Conclusions: A high prevalence of periapical lesions, retained roots, and alveolar bone loss was found among a sample of young female dental attendees, as shown by their panoramic radiographs. Further studies are needed to explore potential risk factors for such a noticeable trend of poor oral health, and the needed strategies to counteract this trend. PMID:28316945

Effect of therapeutic jaw exercise on temporomandibular disorders in individuals with chronic whiplash-associated disorders.

PubMed

Klobas, Luciano; Axelsson, Susanna; Tegelberg, Ake

2006-11-01

The aim of this study was to investigate the effect of a specific therapeutic jaw exercise on the temporomandibular disorders of patients with chronic whiplash-associated disorders. Ninety-four consecutive patients with whiplash-related conditions were referred to and accepted for a treatment period at a center for functional evaluation and rehabilitation during 2001-2002. The patients followed a program of physical therapy, occupational therapy, and pain management. At the start of their stay, they were examined by a physician specialized in rehabilitation medicine and also by a dentist who performed a functional examination of the stomatognathic system. Of the 93 patients who accepted participation in the study, 55 were diagnosed with temporomandibular disorders and chronic whiplash-associated disorders in accordance with the inclusion criteria. They were randomized into a jaw exercise group (n = 25), who performed specific therapeutic jaw exercises, and a control group (n = 30). Both groups undertook the whiplash rehabilitation program at the center. There were no inter- or intra-group differences in symptoms and signs of temporomandibular disorders at baseline, nor at the 3-week and 6-month follow-ups, except for an increase of maximum active mouth-opening capacity in the control group. In conclusion, the therapeutic jaw exercises, in addition to the regular whiplash rehabilitation program, did not reduce symptoms and signs of temporomandibular disorders in patients with chronic whiplash-associated disorders.

A fixed-jaw method to protect critical organs during intensity-modulated radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Jiayun; Chen, Xinyuan; Huang, Manni, E-mail: dai_jianrong@163.com

2014-01-01

Intensity-modulated radiotherapy (IMRT) plays an important role in cancer radiotherapy. For some patients being treated with IMRT, the extremely low tolerances of critical organs (such as lens, ovaries, and testicles) cannot be met during treatment planning. The aim of this article is to introduce a new planning method to overcome that problem. In current planning practice, jaw positions are automatically set to cover all target volumes by the planning system (e.g., Pinnacle{sup 3} system). Because of such settings, critical organs may be fully blocked by the multileaf collimator (MLC), but they still sit in the field that is shaped bymore » collimator jaws. These critical organs receive doses from the transmission and leakage of MLC leaves. We manually fixed jaw positions to block them to further reduce such doses. This method has been used for different treatment sites in our clinic, and it was thoroughly evaluated in patients with radical hysterectomy plus ovarian transposition after surgery. For each patient, 2 treatment plans were designed with the same optimization parameters: the original plan with automatically chosen jaw positions (called O-plan) and the plan with fixed-jaw positions (named F-plan). In the F-plan, the jaws were manually fixed to block the ovaries. For target coverage, the mean conformity index (CI) of the F-plan (1.28 ± 0.02) was remarkably lower than that of the O-plan (1.53 ± 0.09) (p < 0.05). The F-plan and the O-plan performed similarly in target dose homogeneity. Meanwhile, for the critical organ sparing, the mean dose of both ovaries were much lower in the F-plan than that in the O-plan (p < 0.05). The V{sub 20}, V{sub 30}, and V{sub 40} of bladder were also lower in the F-plan (93.57 ± 1.98, 73.99 ± 5.76, and 42.33 ± 3.7, respectively) than those in the O-plan (97.98 ± 1.11, 85.07 ± 4.04, and 49.71 ± 3.63, respectively) (p < 0.05). The maximum dose to the spinal cord planning organ at risk (OAR) volume (PRV) in the O

Bone-Breaking Bite Force of Basilosaurus isis (Mammalia, Cetacea) from the Late Eocene of Egypt Estimated by Finite Element Analysis

PubMed Central

Snively, Eric; Fahlke, Julia M.; Welsh, Robert C.

2015-01-01

Bite marks suggest that the late Eocence archaeocete whale Basilosaurus isis (Birket Qarun Formation, Egypt) fed upon juveniles of the contemporary basilosaurid Dorudon atrox. Finite element analysis (FEA) of a nearly complete adult cranium of B. isis enables estimates of its bite force and tests the animal’s capabilities for crushing bone. Two loadcases reflect different biting scenarios: 1) an intitial closing phase, with all adductors active and a full condylar reaction force; and 2) a shearing phase, with the posterior temporalis active and minimized condylar force. The latter is considered probable when the jaws were nearly closed because the preserved jaws do not articulate as the molariform teeth come into occulusion. Reaction forces with all muscles active indicate that B. isis maintained relatively greater bite force anteriorly than seen in large crocodilians, and exerted a maximum bite force of at least 16,400 N at its upper P3. Under the shearing scenario with minimized condylar forces, tooth reaction forces could exceed 20,000 N despite lower magnitudes of muscle force. These bite forces at the teeth are consistent with bone indentations on Dorudon crania, reatract-and-shear hypotheses of Basilosaurus bite function, and seizure of prey by anterior teeth as proposed for other archaeocetes. The whale’s bite forces match those estimated for pliosaurus when skull lengths are equalized, suggesting similar tradeoffs of bite function and hydrodynamics. Reaction forces in B. isis were lower than maxima estimated for large crocodylians and carnivorous dinosaurs. However, comparison of force estimates from FEA and regression data indicate that B. isis exerted the largest bite forces yet estimated for any mammal, and greater force than expected from its skull width. Cephalic feeding biomechanics of Basilosaurus isis are thus consistent with habitual predation. PMID:25714832

Bone-breaking bite force of Basilosaurus isis (Mammalia, Cetacea) from the late Eocene of Egypt estimated by finite element analysis.

PubMed

Snively, Eric; Fahlke, Julia M; Welsh, Robert C

2015-01-01

Bite marks suggest that the late Eocence archaeocete whale Basilosaurus isis (Birket Qarun Formation, Egypt) fed upon juveniles of the contemporary basilosaurid Dorudon atrox. Finite element analysis (FEA) of a nearly complete adult cranium of B. isis enables estimates of its bite force and tests the animal's capabilities for crushing bone. Two loadcases reflect different biting scenarios: 1) an intitial closing phase, with all adductors active and a full condylar reaction force; and 2) a shearing phase, with the posterior temporalis active and minimized condylar force. The latter is considered probable when the jaws were nearly closed because the preserved jaws do not articulate as the molariform teeth come into occulusion. Reaction forces with all muscles active indicate that B. isis maintained relatively greater bite force anteriorly than seen in large crocodilians, and exerted a maximum bite force of at least 16,400 N at its upper P3. Under the shearing scenario with minimized condylar forces, tooth reaction forces could exceed 20,000 N despite lower magnitudes of muscle force. These bite forces at the teeth are consistent with bone indentations on Dorudon crania, reatract-and-shear hypotheses of Basilosaurus bite function, and seizure of prey by anterior teeth as proposed for other archaeocetes. The whale's bite forces match those estimated for pliosaurus when skull lengths are equalized, suggesting similar tradeoffs of bite function and hydrodynamics. Reaction forces in B. isis were lower than maxima estimated for large crocodylians and carnivorous dinosaurs. However, comparison of force estimates from FEA and regression data indicate that B. isis exerted the largest bite forces yet estimated for any mammal, and greater force than expected from its skull width. Cephalic feeding biomechanics of Basilosaurus isis are thus consistent with habitual predation.

Msx-1 is suppressed in bisphosphonate-exposed jaw bone analysis of bone turnover-related cell signalling after bisphosphonate treatment.

PubMed

Wehrhan, F; Hyckel, P; Amann, K; Ries, J; Stockmann, P; Schlegel, Ka; Neukam, Fw; Nkenke, E

2011-05-01

Bone-destructive disease treatments include bisphosphonates and antibodies against receptor activator for nuclear factor κB ligand (aRANKL). Osteonecrosis of the jaw (ONJ) is a side-effect. Aetiopathology models failed to explain their restriction to the jaw. The osteoproliferative transcription factor Msx-1 is expressed constitutively only in mature jaw bone. Msx-1 expression might be impaired in bisphosphonate-related ONJ. This study compared the expression of Msx-1, Bone Morphogenetic Protein (BMP)-2 and RANKL, in ONJ-affected and healthy jaw bone. An automated immunohistochemistry-based alkaline phosphatase-anti-alkaline phosphatase method was used on ONJ-affected and healthy jaw bone samples (n = 20 each): cell-number ratio (labelling index, Bonferroni adjustment). Real-time RT-PCR was performed to quantitatively compare Msx-1, BMP-2, RANKL and GAPDH mRNA levels. Labelling indices were significantly lower for Msx-1 (P < 0.03) and RANKL (P < 0.003) and significantly higher (P < 0.02) for BMP-2 in ONJ compared with healthy bone. Expression was sevenfold lower (P < 0.03) for Msx-1, 22-fold lower (P < 0.001) for RANKL and eightfold higher (P < 0.02) for BMP-2 in ONJ bone. Msx-1, RANKL suppression and BMP-2 induction were consistent with the bisphosphonate-associated osteopetrosis and impaired bone remodelling in BP- and aRANKL-induced ONJ. Msx-1 suppression suggested a possible explanation of the exclusivity of ONJ in jaw bone. Functional analyses of Msx-1- RANKL interaction during bone remodelling should be performed in the future. © 2011 John Wiley & Sons A/S.

[The clinical and X-ray classification of osteonecrosis of the low jaw].

PubMed

Medvedev, Iu A; Basin, E M; Sokolina, I A

2013-01-01

To elaborate a clinical and X-ray classification of osteonecrosis of the low jaw in people with desomorphine or pervitin addiction. Ninety-two patients with drug addiction who had undergone orthopantomography, direct frontal X-ray of the skull, and multislice computed tomography, followed by multiplanar and three-dimensional imaging reconstruction were examined. One hundred thirty four X-ray films and 74 computed tomographic images were analyzed. The authors proposed a clinical and X-ray classification of osteonecrosis of the low jaw in people with desomorphine or pervitin addiction and elaborated recommendations for surgical interventions on the basis of the developed classification. The developed clinical and X-ray classification and recommendations for surgical interventions may be used to treat osteonecroses of various etiology.

Bisphosphonate-associated Osteonecrosis of the jaws and endodontic treatment: two case reports.

PubMed

Goodell, Gary

2006-01-01

Bisphosphonates are commonly used in the management of bone diseases, such as osteoporosis and Paget's disease, and to prevent bone complications and treat malignant hypercalcemia in certain types of cancer. Although this class of drugs has clear evidence of medical efficacy, there are an, increasing number of reports of bisphosphonate-associated osteonecrosis of the jaws that have substantial implications for the patient and for the treating dentist. This article reviews proposed possible mechanisms of bisphosphonate-associated osteonecrosis of the jaws and describes two case reports where non-surgical and surgical root canal treatment were precipitating factors. Recommendations for prevention and treatment of the disease follow. Thorough history-taking and timely consultation with the patient's oral surgeon and oncologist are emphasized.

Comparison of immediate complete denture, tooth and implant-supported overdenture on vertical dimension and muscle activity

PubMed Central

Shah, Farhan Khalid; Gebreel, Ashraf; Elshokouki, Ali hamed; Habib, Ahmed Ali

2012-01-01

PURPOSE To compare the changes in the occlusal vertical dimension, activity of masseter muscles and biting force after insertion of immediate denture constructed with conventional, tooth-supported and Implant-supported immediate mandibular complete denture. MATERIALS AND METHODS Patients were selected and treatment was carried out with all the three different concepts i.e, immediate denture constructed with conventional (Group A), tooth-supported (Group B) and Implant-supported (Group C) immediate mandibular complete dentures. Parameters of evaluation and comparison were occlusal vertical dimension measured by radiograph (at three different time intervals), Masseter muscle electromyographic (EMG) measurement by EMG analysis (at three different positions of jaws) and bite force measured by force transducer (at two different time intervals). The obtained data were statistically analyzed by using ANOVA-F test at 5% level of significance. If the F test was significant, Least Significant Difference test was performed to test further significant differences between variables. RESULTS Comparison between mean differences in occlusal vertical dimension for tested groups showed that it was only statistically significant at 1 year after immediate dentures insertion. Comparison between mean differences in wavelet packet coefficients of the electromyographic signals of masseter muscles for tested groups was not significant at rest position, but significant at initial contact position and maximum voluntary clench position. Comparison between mean differences in maximum biting force for tested groups was not statistically significant at 5% level of significance. CONCLUSION Immediate complete overdentures whether tooth or implant supported prosthesis is recommended than totally mucosal supported prosthesis. PMID:22737309

Indirect Estimates of Jaw Muscle Tension in Children with Suspected Hypertonia, Children with Suspected Hypotonia, and Matched Controls

ERIC Educational Resources Information Center

Connaghan, Kathryn P.; Moore, Christopher A.

2013-01-01

Purpose: In this study, the authors compared indirect estimates of jaw-muscle tension in children with suspected muscle-tone abnormalities with age- and gender-matched controls. Method: Jaw movement and muscle activation were measured in children (ages 3 years, 11 months, to 10 years) with suspected muscle-tone abnormalities (Down syndrome or…

Raman Spectroscopic Analyses of Jaw Periosteal Cell Mineralization

PubMed Central

Brauchle, Eva; Carvajal Berrio, Daniel; Rieger, Melanie; Schenke-Layland, Katja; Reinert, Siegmar

2017-01-01

To achieve safer patient treatments, serum-free cell culture conditions have to be established for cell therapies. In previous studies, we demonstrated that serum-free culture favored the proliferation of MSCA-1+ osteoprogenitors derived from the jaw periosteum. In this study, the in vitro formation of bone-specific matrix by MSCA-1+ jaw periosteal cells (JPCs, 3 donors) was assessed and compared under serum-free and serum-containing media conditions using the marker-free Raman spectroscopy. Based on a standard fluorescence assay, JPCs from one patient were not able to mineralize under serum-containing culture conditions, whereas the other cells showed similar mineralization levels under both conditions. Raman spectra from mineralizing MSCA-1+ JPCs revealed higher levels of hydroxyapatite formation and higher mineral to matrix ratios under serum-free culture conditions. Higher carbonate to phosphate ratios and higher crystallinity in JPCs cultured under serum-containing conditions indicated immature bone formation. Due to reduced collagen production under serum-free conditions, we obtained significant differences in collagen maturity and proline to hydroxyproline ratios compared to serum-free conditions. We conclude that Raman spectroscopy is a useful tool for the assessment and noninvasive monitoring of in vitro mineralization of osteoprogenitor cells. Further studies should extend this knowledge and improve JPC mineralization by optimizing culture conditions. PMID:28232849

Pathological and clinical features of primary osseous tumours of the jaw.

PubMed

Sarkar, Reena

2014-11-01

Primary bone tumors of the jaw are rare. The neoplastic cells in these tumors are the osteoblasts and osteoclasts. The gnathic bone tumors have also been referred to as borderline. The clinicopathologic approach towards these bony lesions have been reviewed.

A description on pharyngeal jaw apparatus and diets of halfbeak fish Zenarchopterus buffonis (Valenciennes 1847) in Malaysian waters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abidin, Diana Atiqah Zainal, E-mail: diana.atiqah@gmail.com; Hashim, Marina; Ghaffar, Mazlan Abd., E-mail: magfish05@yahoo.com

2015-09-25

Information on the feeding mechanism and diet of halfbeak fish species in harsh estuarine environment ecosystem is still lacking. The present study investigates the fine structure of pharyngeal jaw apparatus and diets of halfbeak fish Zenarchopterus buffonis. A total of 84 halfbeak fish samples have been collected from the coastal water of Peninsular Malaysia using fishing rod. Scanning electron microscopy was used to examine the micrographs of fine microstructure of the pharyngeal teeth. The fundamental anatomy of pharyngeal jaw apparatus displayed that the upper pharyngeal jaw (third pharyngobranchials) displays larger size of hook-like or tricuspid teeth which was analogous tomore » tricuspid morphology. The lower pharyngeal jaw (fifth ceratobranchial) bears mainly conical teeth and appears triangular shape with two, short projections. The estimated TROPH values (1 − 3.2±0.55) denoted that halfbeak fish were omnivores in nature. The findings of this study was found to be useful as a baseline information for a better representation of the trophic flows associated with large medium and small surface water fishes.« less

A description on pharyngeal jaw apparatus and diets of halfbeak fish Zenarchopterus buffonis (Valenciennes 1847) in Malaysian waters

NASA Astrophysics Data System (ADS)

Abidin, Diana Atiqah Zainal; Hashim, Marina; Das, Simon K.; Ghaffar, Mazlan Abd.

2015-09-01

Information on the feeding mechanism and diet of halfbeak fish species in harsh estuarine environment ecosystem is still lacking. The present study investigates the fine structure of pharyngeal jaw apparatus and diets of halfbeak fish Zenarchopterus buffonis. A total of 84 halfbeak fish samples have been collected from the coastal water of Peninsular Malaysia using fishing rod. Scanning electron microscopy was used to examine the micrographs of fine microstructure of the pharyngeal teeth. The fundamental anatomy of pharyngeal jaw apparatus displayed that the upper pharyngeal jaw (third pharyngobranchials) displays larger size of hook-like or tricuspid teeth which was analogous to tricuspid morphology. The lower pharyngeal jaw (fifth ceratobranchial) bears mainly conical teeth and appears triangular shape with two, short projections. The estimated TROPH values (1 - 3.2±0.55) denoted that halfbeak fish were omnivores in nature. The findings of this study was found to be useful as a baseline information for a better representation of the trophic flows associated with large medium and small surface water fishes.

An unusual case of osteonecrosis of the jaw associated with dengue fever and periodontitis.

PubMed

Indurkar, M S; Sethi, R

2016-03-01

Osteonecrosis is a disorder rarely occurring in the jaw. Dengue fever is a common mosquito-borne disease prevalent in many countries including India. The following report presents an interesting case of maxillary osteonecrosis in a middle aged male with a history of dengue infection. We also diagnosed symptoms of chronic periodontitis, which may have potentiated the necrosis. This case report will describe a novel clinical presentation and management of osteonecrosis of the jaw (ONJ) of unknown origin and a possible pathogenesis explaining the association of ONJ with dengue fever and periodontitis. © 2015 Australian Dental Association.

12. CLOSEUP OF THE CURRENT TRASH RAKELIFTING MECHANISM (CALLED 'JAWS' ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. CLOSE-UP OF THE CURRENT TRASH RAKE-LIFTING MECHANISM (CALLED 'JAWS' BY THE PRESENT OPERATORS), LOOKING WEST. THIS EQUIPMENT WAS REMOVED IN AUTUMN OF 1996. - Washington Water Power Company Post Falls Power Plant, Middle Channel Powerhouse & Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

Rhythmic chewing with oral jaws in teleost fishes: a comparison with amniotes.

PubMed

Gintof, Chris; Konow, Nicolai; Ross, Callum F; Sanford, Christopher P J

2010-06-01

Intra-oral prey processing (chewing) using the mandibular jaws occurs more extensively among teleost fishes than previously documented. The lack of muscle spindles, gamma-motoneurons and periodontal afferents in fishes makes them useful for testing hypotheses regarding the relationship between these sensorimotor components and rhythmic chewing in vertebrates. Electromyography (EMG) data from the adductor mandibulae (AM) were used to quantify variation in chew cycle duration in the bowfin Amia, three osteoglossomorphs (bony-tongues), four salmonids and one esocid (pike). All species chewed prey using their oral jaw in repetitive trains of between 3 and 30 consecutive chews, a pattern that resembles cyclic chewing in amniote vertebrates. Variance in rhythmicity was compared within and between lineages using coefficients of variation and Levene's test for homogeneity of variance. These comparisons revealed that some teleosts exhibit degrees of rhythmicity that are comparable to mammalian mastication and higher than in lepidosaurs. Moreover, chew cycle durations in fishes, as in mammals, scale positively with mandible length. Chewing among basal teleosts may be rhythmic because it is stereotyped and inflexible, the result of patterned interactions between sensory feedback and a central pattern generator, because the lack of a fleshy tongue renders jaw-tongue coordination unnecessary and/or because stereotyped opening and closing movements are important for controlling fluid flow in the oral cavity.

Jaw Intraosseous Lesions Biopsied Extracted From 1998 to 2010 in an Iranian Population

PubMed Central

Jamshidi, Shokoofeh; Shojaei, Setareh; Roshanaei, Ghodratollah; Modabbernia, Shirin; Bakhtiary, Esmaeel

2015-01-01

Background: Jaw bones might be potential locations for different lesions. Differences in prevalence and the type of lesions can help in designing and programming prevention procedures in health care centers. Objectives: The aim of the present study was to evaluate the prevalence of intraosseous lesions in the jaws of patients referred to diagnostic and therapeutic centers in Hamadan during 1990-2010. Patients and Methods: This cross-sectional descriptive analytical study was carried out in Hamadan in 2011. Data sheets of the subjects were used to collect all the data of patients with intraosseous lesions, including their age, gender, location of the lesion, the radiographic view of lesions, and their type and histopathological diagnoses. Data were analyzed with SPSS, using means and frequencies. Results: A total of 284 intraosseous lesions were reported in our study. The mean age of the subjects was 28.8 ± 15.2 years. The lesions were distributed in males and females almost similarly. The most prevalent lesions were cystic lesions (54.58%), manifestations of systemic conditions in jaw bones (18.3%), benign tumors (15.5%), malignant lesions (6.7%), and inflammatory lesions (4.92%), in a descending order. The most common cystic lesion was radicular cyst; the most common manifestation of systemic conditions in jaw bones was central giant cell granuloma; the most common benign tumor was ameloblastoma; the most common malignant lesion was osteosarcoma; and the most common inflammatory lesion was periapical granuloma. Conclusions: Our data provided information on the prevalence and types of intraosseous lesions among an Iranian population. This study provided baseline information to help in designing and programming procedures in health care centers in every community so that preventive therapeutic measures can be adopted. PMID:26328061

Jaws for a spiral-tooth whorl: CT images reveal novel adaptation and phylogeny in fossil Helicoprion

PubMed Central

Tapanila, Leif; Pruitt, Jesse; Pradel, Alan; Wilga, Cheryl D.; Ramsay, Jason B.; Schlader, Robert; Didier, Dominique A.

2013-01-01

New CT scans of the spiral-tooth fossil, Helicoprion, resolve a longstanding mystery concerning the form and phylogeny of this ancient cartilaginous fish. We present the first three-dimensional images that show the tooth whorl occupying the entire mandibular arch, and which is supported along the midline of the lower jaw. Several characters of the upper jaw show that it articulated with the neurocranium in two places and that the hyomandibula was not part of the jaw suspension. These features identify Helicoprion as a member of the stem holocephalan group Euchondrocephali. Our reconstruction illustrates novel adaptations, such as lateral cartilage to buttress the tooth whorl, which accommodated the unusual trait of continuous addition and retention of teeth in a predatory chondrichthyan. Helicoprion exemplifies the climax of stem holocephalan diversification and body size in Late Palaeozoic seas, a role dominated today by sharks and rays. PMID:23445952

Expeditionary Operations Require Joint Force Capabilities in the Future Operating Environment

DTIC Science & Technology

2013-03-01

endeavor, I would like to thank COL Purvis, and the professionals of JAWS Seminar 2 for letting me try to weave my thesis into almost every seminar...joint sea base, expeditionary strike group, or task force. JP 4-0, JSHIP JT&E, ’DLQ MOU Notes: The AFSB is to exploit the flexibility and...of the global commons and select sovereign territory, waters , airspace and cyberspace. 14  The combat task of overcoming the enemy’s anti-access

Concurrence of lower jaw skeletal anomalies in triploid Atlantic salmon (Salmo salar L.) and the effect on growth in freshwater.

PubMed

Amoroso, G; Cobcroft, J M; Adams, M B; Ventura, T; Carter, C G

2016-12-01

Triploid Atlantic salmon populations are associated with higher prevalence of lower jaw skeletal anomalies affecting fish performance, welfare and value deleteriously. Anomalous lower jaw can be curved downward (LJD), shortened (SJ) or misaligned (MA). Two separate groups of triploid Atlantic salmon (~12 g) with either normal lower jaw (NOR) or SJ were visually assessed four times over three months for presence and concurrence of jaw anomalies (with severity classified) and opercular shortening to understand the relatedness of these anomalous developmental processes. The prevalence of jaw anomalies increased in both groups over time (NOR group - SJ, LJD and MA combined 0-24.5%; SJ group - LJD and MA combined 17-31%). SJ and LJD occurred both independently and concurrently whereas MA exclusively concurred with them. All three anomalies could be concurrent. Severity of both LJD and SJ increased in the SJ group only. Opercular shortening recovery was observed in both groups but at a slower rate in the SJ group. The SJ group specific growth rate (SGR) was significantly (P < 0.05) lower than the NOR group. This study demonstrated the concurrence of SJ, LJD and MA and showed possible deleterious consequences deriving from the conditions. © 2016 John Wiley & Sons Ltd.

Clinical assessment of the jaw-tracking function in IMRT for a brain tumor

NASA Astrophysics Data System (ADS)

Kim, Jin-Young; Kim, Shin-Wook; Choe, Bo-Young; Suh, Tae-Suk; Park, Sung-Kwang; Jo, Sun-Mi; Oh, Won-Yong; Shin, Jung-Wook; Cho, Gyu-Seok; Nam, Sang-Hee; Chung, Jin-Beom; Kim, Jung-Ki; Lee, Young-Kyu

2015-01-01

Intensity-modulated radiotherapy (IMRT) improves dose conformity and saves critical organs. IMRT is widely used in cases of head and neck, prostate, and brain cancer due to the close location of the targets to critical structures. However, because IMRT has a larger amount of radiation exposure than 3 dimensional-conformal radiation therapy (3D-CRT), it has disadvantages such as increases in the low dose irradiation to normal tissues and in the accumulated dose for the whole volume due to leakage and transmission of the multi-leaf collimator (MLC). The increased accumulated dose and the larger low dose may increase the occurrence of secondary malignant neoplasms. For these reasons, the jaw-tracking function of the TrueBeam (Varian Medical Systems, Palo Alto, CA) was developed to reduce the leakage and the transmission dose of the MLC with linear accelerators. However, the change in the superficial dose has not been verified with a quantitative analysis of the dose reduction in a brain tumor. Therefore, in the present study, we intended to verify the clinical possibility of utilizing the jaw-tracking function for a brain tumor by comparing treatment plans and superficial doses. To accomplish this, we made three types of original treatment plans using Eclipse11 (Varian Medical Systems, Palo Alto, CA): 1) farther than 2 cm from the organs at risk (OAR); 2) within 2 cm of the OAR; and 3) intersecting with the OAR. Jaw-tracking treatment plans were also made with copies of the original treatment plan using Smart LMC Version 11.0.31 (Varian Medical Systems, Palo Alto, CA). A comparison between the original treatment plans and jaw-tracking treatment plans was performed using the difference of the mean dose and maximum dose to the OARs in cumulative Dose Volume Histogram (DVH). In addition, the dependencies of the effects of transmission and the scattering doses according to jaw motion were assessed through the difference in the surface doses. In the DVH comparison, a

Masticatory myosin unveiled: first determination of contractile parameters of muscle fibers from carnivore jaw muscles.

PubMed

Toniolo, Luana; Cancellara, Pasqua; Maccatrozzo, Lisa; Patruno, Marco; Mascarello, Francesco; Reggiani, Carlo

2008-12-01

Masticatory myosin heavy chain (M MyHC) is a myosin subunit isoform with expression restricted to muscles derived from the first branchial arch, such as jaw-closer muscles, with pronounced interspecies variability. Only sparse information is available on the contractile properties of muscle fibers expressing M MyHC (M fibers). In this study, we characterized M fibers isolated from the jaw-closer muscles (temporalis and masseter) of two species of domestic carnivores, the cat and the dog, compared with fibers expressing slow or fast (2A, 2X, and 2B) isoforms. In each fiber, during maximally calcium-activated contractions at 12 degrees C, we determined isometric-specific tension (P(o)), unloaded shortening velocity (v(o)) with the slack test protocol, and the rate constant of tension redevelopment (K(TR)) after a fast shortening-relengthening cycle. At the end of the mechanical experiment, we identified MyHC isoform composition of each fiber with gel electrophoresis. Electrophoretic migration rate of M MyHC was similar in both species. We found that in both species the kinetic parameters v(o) and K(TR) of M fibers were similar to those of 2A fibers, whereas P(o) values were significantly greater than in any other fiber types. The similarity between 2A and M fibers and the greater tension development of M fibers were confirmed also in mechanical experiments performed at 24 degrees C. Myosin concentration was determined in single fibers and found not different in M fibers compared with slow and fast fibers, suggesting that the higher tension developed by M fibers does not find an explanation in a greater number of force generators. The specific mechanical characteristics of M fibers might be attributed to a diversity in cross-bridge kinetics.

Thermal resilient multiple jaw braze fixture

DOEpatents

Ney, Robert; Perrone, Alex J.

1995-07-11

A braze fixture has side walls forming a cavity with an opening to receive a stack of parts to be brazed. Sidewalls of the housing have a plurality of bearing receiving openings into which bearing rods or jaws are inserted to align the stacked elements of the workpiece. The housing can also have view ports to allow a visual check of the alignment. Straps or wires around the fixture are selected to have thermal characteristics similar to the thermal characteristics of the workpiece undergoing brazing. The straps or wires make physical contact with the bearing rods thereby causing bearing rods to maintain the workpiece in proper alignment throughout the entire brazing cycle.

Thermal resilient multiple jaw braze fixture

DOEpatents

Ney, R.; Perrone, A.J.

1995-07-11

A braze fixture has side walls forming a cavity with an opening to receive a stack of parts to be brazed. Sidewalls of the housing have a plurality of bearing receiving openings into which bearing rods or jaws are inserted to align the stacked elements of the workpiece. The housing can also have view ports to allow a visual check of the alignment. Straps or wires around the fixture are selected to have thermal characteristics similar to the thermal characteristics of the workpiece undergoing brazing. The straps or wires make physical contact with the bearing rods thereby causing bearing rods to maintain the workpiece in proper alignment throughout the entire brazing cycle. 9 figs.

Giant cell lesion of the jaw as a presenting feature of Noonan syndrome.

PubMed

Sinnott, Bridget P; Patel, Maya

2018-05-30

This is a case of a 20-year-old woman who presented with a left jaw mass which was resected and found to be a giant cell granuloma of the mandible. Her history and physical examination were suggestive for Noonan syndrome which was confirmed with genetic testing and the finding of a PTPN11 gene mutation which has rarely been associated with giant cell lesions of the jaw. Given her particular genetic mutation and the presence of a giant cell lesion, we present a case of Noonan-like/multiple giant cell lesion syndrome. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Effects of over-the-counter jaw-repositioning mouth guards on dynamic balance, flexibility, agility, strength, and power in college-aged male athletes.

PubMed

Golem, Devon L; Arent, Shawn M

2015-02-01

Improvements in muscular power and anaerobic performance have resulted from the use of jaw-repositioning mouth guards designed with advanced dental techniques. The high cost of such techniques has dissuaded the widespread use. Recently, more affordable, over-the-counter (OTC) jaw-repositioning mouth guards have become available. The primary objective of this study was to examine the effects of 2 OTC jaw-repositioning mouth guards on muscular power and strength performance in college-aged male athletes. It was hypothesized that similar to previous observations with advanced dentistry-designed mouth guards, OTC jaw-repositioning mouth guards would impart positive effects on muscular power but not have any effect on muscular strength. Secondary objectives of this study included the examination of the effects of 2 OTC jaw-repositioning mouth guards on other variables related to athletic performance. Male collegiate athletes (N = 20) participated in 4 separate testing sessions that consisted of assessment of muscular power, dynamic balance, flexibility, agility, and muscular strength. The 4 conditions, 1 per testing session, were assigned in a randomized order and consisted of a no-mouth guard control (CON), a placebo mouth guard, a self-adapted jaw-repositioning mouth guard (SA), and a custom-fitted jaw-repositioning mouth guard (CF). No significant differences were observed between conditions in muscular power (p = 0.78), dynamic balance (p = 0.99), agility (p = 0.22), or muscular strength (p = 0.47). The CF had significantly lower hip flexion than the CON (p = 0.014) and had significantly greater lumbar spine lateral flexion compared with the SA condition (p = 0.054). However, these flexibility differences lack practical relevance as the effect sizes remain very small (ES = -0.27 and -0.14, respectively). In conclusion, the jaw-repositioning technique used in the design of these OTC mouth guards did not affect performance. It is important to note that negative

Evaluation of the pair-culture effect in Ophyryotrocha puerilis (Polychaeta: Dorvilleidae). II. Conditions for the moult of the upper jaw

NASA Astrophysics Data System (ADS)

Kegel, B.; Pfannenstiel, H.-D.

1983-06-01

The conditions for moult of the upper jaw of Ophryotrocha puerilis were determined in isolated individuals and in groups of various sizes. The frequency of formation of the complicated upper jaw in both isolated individuals and in groups varies to a considerable extent. Although formation of the upper jaw and sex reversal normally are associated processes, the relationship of these two processes is not very well understood. Histological investigations at the light microscopic level demonstrate that the dental apparatus is an elaboration of the ectodermal stomodaeum which is considered to be a highly specialized part of the cuticle in the pharyngeal region of the gut.

[Experience of systematization on the treatment of patients with upper jaws fractures, during the period 1991-2000].

PubMed

Khinkov, D

2005-01-01

A retrospecive analysis was done of the 128 patients with fractures in a upper jaw, treated during the period 1991-2000. The treatment of the patients with partial fractures in a alveolar part of maxilla and frontal wall of maxillary sinus, consist of debridement on the open wound, primery stiched and stabilization by arch bar of perspective teeth. In the cases with fractures of tuber maxilla and opening of maxillary sinus they tray to clouse it by Rhermann technique, with or without radical antrothomy by Caldwell-Luc technique. On the patients by total upper jaw fractures they try lead by princip of duble stage fixation: from one side-of intact upper bone structures and the other side-on a mandible. On the cases of upper jaw fractures, combine with barain traums. was treated conservativly - the specialize treatment of facial injures was postpoun until stabilization of brain status.

[Clinical experience in osteoplastic material Allomatrix-implant and fibrin rich platelets use in surgical treatment of jaw radicular cysts].

PubMed

Kuz'minykh, I A

2009-01-01

Bones forming optimizators applying in surgical dentistry is an important element of jaw destructive processes successful treatment. Today use of osteoplastic materials on the collagen basis is widely spread. One of this challenge solution is FRP and Allomatrix-implant material applying to jaws during surgery operations. We described clinical investigation phase: the estimation of postoperative and remote results of treatment was carried out.

Kinetic analysis of concurrent activation potentiation during back squats and jump squats.

PubMed

Ebben, William P; Kaufmann, Clare E; Fauth, McKenzie L; Petushek, Erich J

2010-06-01

Concurrent activation potentiation enhances muscular force during open kinetic chain isometric and isokinetic exercises via remote voluntary contractions (RVCs). The purpose of this study was to evaluate the effect of RVCs on the performance of closed kinetic chain ground-based exercises. Subjects included 13 men (21.4+/-1.5 years) who performed the back squat and jump squat in 2 test conditions. The RVC condition included performing the test exercises while clenching the jaw on a mouth guard, forcefully gripping and pulling the barbell down into the trapezius, and performing a Valsalva maneuver. The normal condition (NO-RVC) included performing the test exercises without RVCs. Exercises were assessed with a force platform. Peak ground reaction force (GRF), rate of force development (RFD) during the first 100 milliseconds (RFD-100), RFD to peak GRF (RFD-P), and jump squat height (JH) were calculated from the force-time records. Data were analyzed using an analysis of variance. Results reveal that GRF and RFD-100 were higher in the RVC compared with the NO-RVC condition for both the back squat and jump squat (p

A novel method for single sample multi-axial nanoindentation of hydrated heterogeneous tissues based on testing great white shark jaws.

PubMed

Ferrara, Toni L; Boughton, Philip; Slavich, Eve; Wroe, Stephen

2013-01-01

Nanomechanical testing methods that are suitable for a range of hydrated tissues are crucial for understanding biological systems. Nanoindentation of tissues can provide valuable insights into biology, tissue engineering and biomimetic design. However, testing hydrated biological samples still remains a significant challenge. Shark jaw cartilage is an ideal substrate for developing a method to test hydrated tissues because it is a unique heterogeneous composite of both mineralized (hard) and non-mineralized (soft) layers and possesses a jaw geometry that is challenging to test mechanically. The aim of this study is to develop a novel method for obtaining multidirectional nanomechanical properties for both layers of jaw cartilage from a single sample, taken from the great white shark (Carcharodon carcharias). A method for obtaining multidirectional data from a single sample is necessary for examining tissue mechanics in this shark because it is a protected species and hence samples may be difficult to obtain. Results show that this method maintains hydration of samples that would otherwise rapidly dehydrate. Our study is the first analysis of nanomechanical properties of great white shark jaw cartilage. Variation in nanomechanical properties were detected in different orthogonal directions for both layers of jaw cartilage in this species. The data further suggest that the mineralized layer of shark jaw cartilage is less stiff than previously posited. Our method allows multidirectional nanomechanical properties to be obtained from a single, small, hydrated heterogeneous sample. Our technique is therefore suitable for use when specimens are rare, valuable or limited in quantity, such as samples obtained from endangered species or pathological tissues. We also outline a method for tip-to-optic calibration that facilitates nanoindentation of soft biological tissues. Our technique may help address the critical need for a nanomechanical testing method that is applicable

A method of indirect registration of the coordinates of condylar points with a six-degree-of-freedom jaw tracker.

PubMed

Huang, B Y; Durrant, C J; Johnson, C W L; Murray, G M

2002-06-30

Previous studies have indicated that the location of a condylar point can significantly influence its trajectory. The aim of this investigation was to develop a method of registering the location of radiographically defined condylar points in the coordinate system of a six-degree-of-freedom jaw-tracking device and to determine the accuracy of this method by using a perspex model in one experiment and a dry skull in another. A direct measurement ('the gold standard') of condylar point coordinates in the coordinate system of JAWS3D was done using a three-dimensional (3D) digitizer (MicroScribe-3DX). The indirect measurement used a distributed fiducial marker as the interface between the coordinate system of MicroScribe-3DX (which was used to register the fiducial marker and the JAWS3D coordinate system) and the coordinate system of the CT scans (used to define condyle anatomy and the relation with the fiducial marker). The coordinates of condylar points could then be calculated in the coordinate system of JAWS3D. The results showed that the indirect method could register condylar point coordinates on either side to an accuracy of approximately 0.5 mm.

Correlation between bone mineral density of jaws and skeletal sites in an Iranian population using dual X-ray energy absorptiometry.

PubMed

Esfahanizadeh, Nasrin; Davaie, Sotoudeh; Rokn, A R; Daneshparvar, Hamid Reza; Bayat, Noushin; Khondi, Nasrin; Ajvadi, Sara; Ghandi, Mostafa

2013-07-01

The aim of the present study was to evaluate the relationship between the bone density of various regions of jaws and skeletal bones. A total of 110 patients with a mean age of 55.01 ± 10.77 years were selected for the purpose of the present descriptive study. Dual X-ray Energy Absorptiometry (DXA) was carried out to determine bone mineral density (BMD) of the femur and lumbar vertebrae. Then all the subjects underwent DXA of the jaw bones and BMD values were determined at four jaw regions. Data were analyzed by SPSS 16 statistical software, and the correlation between the various BMD values was determined by Pearson's correlation coefficient. The results showed that 42.7% of females had normal BMD values in the femur, and in vertebrae, 20% were osteopenic and 37.3% suffered from osteoporosis, with statistically significant differences in the BMD values of the jaws between the three above-mentioned groups (P < 0.001). There was an increasing tendency toward osteopenia and osteoporosis with age. There was a positive correlation between BMD values of the femur and lumbar vertebrae and those of all the jaw regions under study (P < 0.005). There was a negative correlation (P < 0.01) between age and the BMD values of the femur, lumbar vertebrae and anterior maxilla. The bone density of the maxilla and mandible and presence of osteoporosis or osteopenia in these bones might reflect the same problem in skeletal bones.

Morphology of the jaw, suspensorial, and opercle musculature of Beloniformes and related species (Teleostei: Acanthopterygii), with a special reference to the m. adductor mandibulae complex.

PubMed

Werneburg, Ingmar

2015-01-01

The taxon Beloniformes represents a heterogeneous group of teleost fishes that show an extraordinary diversity of jaw morphology. I present new anatomical descriptions of the jaw musculature in six selected beloniforms and four closely related species. A reduction of the external jaw adductor (A1) and a changed morphology of the intramandibular musculature were found in many Beloniformes. This might be correlated with the progressively reduced mobility of the upper and lower jaw bones. The needlefishes and sauries, which are characterised by extremely elongated and stiffened jaws, show several derived characters, which in combination enable the capture of fish at high velocity. The ricefishes are characterised by several derived and many plesiomorphic characters that make broad scale comparisons difficult. Soft tissue characters are highly diverse among hemiramphids and flying fishes reflecting the uncertainty about their phylogenetic position and interrelationship. The morphological findings presented herein may help to interpret future phylogenetic analyses using cranial musculature in Beloniformes.

[Acupuncture combined with magnetic therapy for treatment of temple-jaw joint dysfunction].

PubMed

Wang, Xiao-Hui; Zhang, Wen

2009-04-01

To compare clinical therapeutic effects of acupuncture combined with magnetic therapy and simple magnetic therapy on temple-jaw joint dysfunction. Eighty-two cases were randomly divided into an observation group (n = 52) and a control group (n = 30). The observation group was treated with acupuncture at Xiaguan (ST 7), Jiache (ST 6), Hegu (LI 4), etc. and AL-2 low frequency electromagnetic comprehensive treatment instrument; the control group was treated with AL-2 low frequency electromagnetic comprehensive treatment instrument. The cured and markedly effective rate of 90.4% in the observation group was significantly better than 66.7% in the control group (P < 0.01), and the total effective rate of 98.1% in the observation group was significantly better than 86.7% in the control group (P < 0.05). The therapeutic effect of acupuncture combined with magnetic therapy is significantly better than that of the simple magnetic therapy on temple-jaw joint dysfunction.

Interaction between Foxc1 and Fgf8 during Mammalian Jaw Patterning and in the Pathogenesis of Syngnathia

PubMed Central

Inman, Kimberly E.; Purcell, Patricia; Kume, Tsutomu; Trainor, Paul A.

2013-01-01

Syngnathia (bony fusion of the upper and lower jaw) is a rare human congenital condition, with fewer than sixty cases reported in the literature. Syngnathia typically presents as part of a complex syndrome comprising widespread oral and maxillofacial anomalies, but it can also occur in isolation. Most cartilage, bone, and connective tissue of the head and face is derived from neural crest cells. Hence, congenital craniofacial anomalies are often attributed to defects in neural crest cell formation, survival, migration, or differentiation. The etiology and pathogenesis of syngnathia however remains unknown. Here, we report that Foxc1 null embryos display bony syngnathia together with defects in maxillary and mandibular structures, and agenesis of the temporomandibular joint (TMJ). In the absence of Foxc1, neural crest cell derived osteogenic patterning is affected, as osteoblasts develop ectopically in the maxillary prominence and fuse with the dentary bone. Furthermore, we observed that the craniofacial musculature is also perturbed in Foxc1 null mice, which highlights the complex tissue interactions required for proper jaw development. We present evidence that Foxc1 and Fgf8 genetically interact and that Fgf8 dosage is associated with variation in the syngnathic phenotype. Together our data demonstrates that Foxc1 – Fgf8 signaling regulates mammalian jaw patterning and provides a mechanistic basis for the pathogenesis of syngnathia. Furthermore, our work provides a framework for understanding jaw patterning and the etiology of other congenital craniofacial anomalies, including temporomandibular joint agenesis. PMID:24385915

Feeding ecology underlies the evolution of cichlid jaw mobility.

PubMed

Martinez, Christopher M; McGee, Matthew D; Borstein, Samuel R; Wainwright, Peter C

2018-06-19

The fish feeding apparatus is among the most diverse functional systems in vertebrates. While morphological and mechanical variation of feeding systems are well studied, we know far less about the diversity of the motions that they produce. We explored patterns of feeding movements in African cichlids from Lakes Malawi and Tanganyika, asking whether the degree of kinesis is associated with dietary habits of species. We used geometric morphometrics to measure feeding kinesis as trajectories of shape change, based on 326 high-speed videos in 56 species. Cranial morphology was significantly related to feeding movements, both of which were distributed along a dietary axis associated with prey evasiveness. Small-mouthed cichlids that feed by scraping algae and detritus from rocks had low kinesis strikes, while large-mouthed species that eat large, evasive prey (fishes and shrimps) generated the greatest kinesis. Despite having higher overall kinesis, comparisons of trajectory shape (linearity) revealed that cichlids that eat mobile prey also displayed more kinematically conserved, or efficient, feeding motions. Our work indicates that prey evasiveness is strongly related to the evolution of cichlid jaw mobility, suggesting that this same relationship may explain the origins and diversity of highly kinetic jaws that characterize the super-radiation of spiny-rayed fishes. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Bayesian Morphological Clock Methods Resurrect Placoderm Monophyly and Reveal Rapid Early Evolution in Jawed Vertebrates.

PubMed

King, Benedict; Qiao, Tuo; Lee, Michael S Y; Zhu, Min; Long, John A

2017-07-01

The phylogeny of early gnathostomes provides an important framework for understanding one of the most significant evolutionary events, the origin and diversification of jawed vertebrates. A series of recent cladistic analyses have suggested that the placoderms, an extinct group of armoured fish, form a paraphyletic group basal to all other jawed vertebrates. We revised and expanded this morphological data set, most notably by sampling autapomorphies in a similar way to parsimony-informative traits, thus ensuring this data (unlike most existing morphological data sets) satisfied an important assumption of Bayesian tip-dated morphological clock approaches. We also found problems with characters supporting placoderm paraphyly, including character correlation and incorrect codings. Analysis of this data set reveals that paraphyly and monophyly of core placoderms (excluding maxillate forms) are essentially equally parsimonious. The two alternative topologies have different root positions for the jawed vertebrates but are otherwise similar. However, analysis using tip-dated clock methods reveals strong support for placoderm monophyly, due to this analysis favoring trees with more balanced rates of evolution. Furthermore, enforcing placoderm paraphyly results in higher levels and unusual patterns of rate heterogeneity among branches, similar to that generated from simulated trees reconstructed with incorrect root positions. These simulations also show that Bayesian tip-dated clock methods outperform parsimony when the outgroup is largely uninformative (e.g., due to inapplicable characters), as might be the case here. The analysis also reveals that gnathostomes underwent a rapid burst of evolution during the Silurian period which declined during the Early Devonian. This rapid evolution during a period with few articulated fossils might partly explain the difficulty in ascertaining the root position of jawed vertebrates. © The Author(s) 2016. Published by Oxford University

Finite Element Analysis of the Cingulata Jaw: An Ecomorphological Approach to Armadillo’s Diets

PubMed Central

Serrano-Fochs, Sílvia; De Esteban-Trivigno, Soledad; Marcé-Nogué, Jordi; Fortuny, Josep; Fariña, Richard A.

2015-01-01

Finite element analyses (FEA) were applied to assess the lower jaw biomechanics of cingulate xenarthrans: 14 species of armadillos as well as one Pleistocene pampathere (11 extant taxa and the extinct forms Vassallia, Eutatus and Macroeuphractus). The principal goal of this work is to comparatively assess the biomechanical capabilities of the mandible based on FEA and to relate the obtained stress patterns with diet preferences and variability, in extant and extinct species through an ecomorphology approach. The results of FEA showed that omnivorous species have stronger mandibles than insectivorous species. Moreover, this latter group of species showed high variability, including some similar biomechanical features of the insectivorous Tolypeutes matacus and Chlamyphorus truncatus to those of omnivorous species, in agreement with reported diets that include items other than insects. It remains unclear the reasons behind the stronger than expected lower jaw of Dasypus kappleri. On the other hand, the very strong mandible of the fossil taxon Vassallia maxima agrees well with the proposed herbivorous diet. Moreover, Eutatus seguini yielded a stress pattern similar to Vassalia in the posterior part of the lower jaw, but resembling that of the stoutly built Macroeuphractus outesi in the anterior part. The results highlight the need for more detailed studies on the natural history of extant armadillos. FEA proved a powerful tool for biomechanical studies in a comparative framework. PMID:25919313

Survival, Function, and Complications of Oral Implants Placed in Bone Flaps in Jaw Rehabilitation: A Systematic Review.

PubMed

Zhang, Lei; Ding, Qian; Liu, Cunrui; Sun, Yannan; Xie, Qiufei; Zhou, Yongsheng

2016-01-01

This systematic review attempted to determine the survival rate of implants placed in bone flaps in jaw rehabilitation and the functional gains and the most common complications related to these implants. An electronic search was undertaken of PubMed, EMBASE, and CNKI records from 1990 through July 2014. Two independent examiners read the titles and abstracts of the results to identify studies that met the inclusion criteria. Subsequently, the reference lists of the selected publications were hand searched. Descriptive statistics were used to report all data related to the survival rate of implants placed in bone flaps in jaw rehabilitation, the functional gains, and complications. A total of 20 studies were included for systematic review without repetition. The mean follow-up time after implant placement ranged from 1.75 to 9.5 years. Within the limitations of available studies, the survival rate of implants placed in bone flaps in jaw rehabilitation ranged from 82.4% to 100%. Of the 20 included studies, 15 reported a survival rate higher than 90%. The cumulative survival rate was 93.2%, with the longest follow-up time being 12.9 years. The most common complications related to these implants were peri-implant bone resorption or peri-implant inflammation, and peri-implant soft tissue proliferation. The main factors associated with the survival rate of implants in bone flaps were reported as time of implant placement and radiotherapy. Despite some persistent soft tissue problems and implant loss, most patients reached a satisfactory functional and esthetic outcome, as evaluated by clinical examination and subjectively by the patients at interview. Implant-supported dental prosthetic rehabilitation in reconstructed jaws improved the quality of life in terms of speech, nutrition, oral competence, and facial appearance. Placement of implants in bone flaps in jaw rehabilitation was demonstrated to be a reliable technique with a high survival rate. Multicentered

Novel System for Bite-Force Sensing and Monitoring Based on Magnetic Near Field Communication

PubMed Central

Lantada, Andres Diaz; Bris, Carlos González; Morgado, Pilar Lafont; Maudes, Jesús Sanz

2012-01-01

Intraoral devices for bite-force sensing have several applications in odontology and maxillofacial surgery, as bite-force measurements provide additional information to help understand the characteristics of bruxism disorders and can also be of help for the evaluation of post-surgical evolution and for comparison of alternative treatments. A new system for measuring human bite forces is proposed in this work. This system has future applications for the monitoring of bruxism events and as a complement for its conventional diagnosis. Bruxism is a pathology consisting of grinding or tight clenching of the upper and lower teeth, which leads to several problems such as lesions to the teeth, headaches, orofacial pain and important disorders of the temporomandibular joint. The prototype uses a magnetic field communication scheme similar to low-frequency radio frequency identification (RFID) technology (NFC). The reader generates a low-frequency magnetic field that is used as the information carrier and powers the sensor. The system is notable because it uses an intra-mouth passive sensor and an external interrogator, which remotely records and processes information regarding a patient's dental activity. This permits a quantitative assessment of bite-force, without requiring intra-mouth batteries, and can provide supplementary information to polysomnographic recordings, current most adequate early diagnostic method, so as to initiate corrective actions before irreversible dental wear appears. In addition to describing the system's operational principles and the manufacture of personalized prototypes, this report will also demonstrate the feasibility of the system and results from the first in vitro and in vivo trials. PMID:23112669

Correlation between bone mineral density of jaws and skeletal sites in an Iranian population using dual X-ray energy absorptiometry

PubMed Central

Esfahanizadeh, Nasrin; Davaie, Sotoudeh; Rokn, A. R.; Daneshparvar, Hamid Reza; Bayat, Noushin; Khondi, Nasrin; Ajvadi, Sara; Ghandi, Mostafa

2013-01-01

Background: The aim of the present study was to evaluate the relationship between the bone density of various regions of jaws and skeletal bones. Materials and Methods: A total of 110 patients with a mean age of 55.01 ± 10.77 years were selected for the purpose of the present descriptive study. Dual X-ray Energy Absorptiometry (DXA) was carried out to determine bone mineral density (BMD) of the femur and lumbar vertebrae. Then all the subjects underwent DXA of the jaw bones and BMD values were determined at four jaw regions. Data were analyzed by SPSS 16 statistical software, and the correlation between the various BMD values was determined by Pearson's correlation coefficient. Results: The results showed that 42.7% of females had normal BMD values in the femur, and in vertebrae, 20% were osteopenic and 37.3% suffered from osteoporosis, with statistically significant differences in the BMD values of the jaws between the three above-mentioned groups (P < 0.001). There was an increasing tendency toward osteopenia and osteoporosis with age. There was a positive correlation between BMD values of the femur and lumbar vertebrae and those of all the jaw regions under study (P < 0.005). There was a negative correlation (P < 0.01) between age and the BMD values of the femur, lumbar vertebrae and anterior maxilla. Conclusion: The bone density of the maxilla and mandible and presence of osteoporosis or osteopenia in these bones might reflect the same problem in skeletal bones. PMID:24130580

Contrast-enhanced multidetector computerized tomography for odontogenic cysts and cystic-appearing tumors of the jaws: is it useful?

PubMed

Kakimoto, Naoya; Chindasombatjaroen, Jira; Tomita, Seiki; Shimamoto, Hiroaki; Uchiyama, Yuka; Hasegawa, Yoko; Kishino, Mitsunobu; Murakami, Shumei; Furukawa, Souhei

2013-01-01

The purpose of this study was to investigate the usefulness of computerized tomography (CT), particularly contrast-enhanced CT, in differentiation of jaw cysts and cystic-appearing tumors. We retrospectively analyzed contrast-enhanced CT images of 90 patients with odontogenic jaw cysts or cystic-appearing tumors. The lesion size and CT values were measured and the short axis to long axis (S/L) ratio, contrast enhancement (CE) ratio, and standard deviation ratio were calculated. The lesion size and the S/L ratio of keratocystic odontogenic tumors were significantly different from those of radicular cysts and follicular cysts. There were no significant differences in the CE ratio among the lesions. Multidetector CT provided diagnostic information about the size of odontogenic cysts and cystic-appearing tumors of the jaws that was related to the lesion type, but showed no relation between CE ratio and the type of these lesions. Copyright © 2013 Elsevier Inc. All rights reserved.

[Permanent constrictions of the jaws (author's transl)].

PubMed

Dupuis, A; Michaud, J

1981-01-01

Permanent constrictions of the jaws are of various types depending on the site of the lesion: temporomaxillary ankylosis, extra-articular constrictions of bone, skin, muscle, or mucosal origin, and those arising from tumors. The commonest cause is injury, those due to infection being currently less frequently observed, which cannot be said for those of tumoral origin. The consequences are difficulty in taking foud and poor buccodental hygiene, while temporomaxillary ankylosis in children provokes mandibular growth disturbances. Surgical treatment is aimed at removing the constriction. Total resection of the ankylosed block is essential to avoid recurrences, while reeducation of buccal opening must be started early and continued for long periods in all cases.

Mechanical constraint from growing jaw facilitates mammalian dental diversity

PubMed Central

Renvoisé, Elodie; Kavanagh, Kathryn D.; Lazzari, Vincent; Häkkinen, Teemu J.; Rice, Ritva; Pantalacci, Sophie; Salazar-Ciudad, Isaac; Jernvall, Jukka

2017-01-01

Much of the basic information about individual organ development comes from studies using model species. Whereas conservation of gene regulatory networks across higher taxa supports generalizations made from a limited number of species, generality of mechanistic inferences remains to be tested in tissue culture systems. Here, using mammalian tooth explants cultured in isolation, we investigate self-regulation of patterning by comparing developing molars of the mouse, the model species of mammalian research, and the bank vole. A distinct patterning difference between the vole and the mouse molars is the alternate cusp offset present in the vole. Analyses of both species using 3D reconstructions of developing molars and jaws, computational modeling of cusp patterning, and tooth explants cultured with small braces show that correct cusp offset requires constraints on the lateral expansion of the developing tooth. Vole molars cultured without the braces lose their cusp offset, and mouse molars cultured with the braces develop a cusp offset. Our results suggest that cusp offset, which changes frequently in mammalian evolution, is more dependent on the 3D support of the developing jaw than other aspects of tooth shape. This jaw–tooth integration of a specific aspect of the tooth phenotype indicates that organs may outsource specific aspects of their morphology to be regulated by adjacent body parts or organs. Comparative studies of morphologically different species are needed to infer the principles of organogenesis. PMID:28808032

[Imaging analysis of jaw defects reparation with antigen-extracted porcine cancellous bone].

PubMed

Chen, Xufeng; Lu, Lihong; Feng, Zhiqiang; Yin, Zhongda; Lai, Renfa

2017-12-01

At present, most of the bone xenograft for clinical application comes from bovine. In recent years, many studies have been done on the clinical application of porcine xenograft bone. The goal of this study was to evaluate the effect of canine mandibular defects reparation with antigen-extracted porcine cancellous bone by imaging examination. Four dogs' bilateral mandibular defects were created, with one side repaired with autologous bone (set as control group) while the other side repaired with antigen-extracted porcine cancellous bone (set as experimental group). Titanium plates and titanium screws were used for fixation. Cone beam computed tomography (CBCT), computed tomography (CT), single-photon emission computed tomography (SPECT) were undertaken at week 12 and 24 postoperatively, and SPECT and CT images were fused. The results demonstrated that the remodeling of antigen-extracted porcine cancellous bone was slower than that of autologous bone, but it can still be used as scaffold for jaw defects. The results in this study provide a new choice for materials required for clinical reparation of jaw defects.

Actinomyces israelii in osteoradionecrosis of the jaws. Histopathologic and immunocytochemical study of five cases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Happonen, R.P.; Viander, M.; Pelliniemi, L.

1983-06-01

Five surgically treated patients with osteoradionecrosis of the jaws are presented. The clinical history of the disease varied from 3 to 17 years. In three cases the progression of the disease was enhanced by surgical procedures performed in the irradiated area causing exfoliation of the premaxillary area in one case and spontaneous mandibular fracture in two cases. Actinomyces israelii was demonstrated in tissue sections of all five cases by using FITC-labeled specific antiserum and additionally with peroxidase-antiperoxidase method in one case. Candida was found in histologic sections of three cases. Radiation damage in the oral soft tissues and jawbones makesmore » the atmosphere favorable for anaerobic microorganisms. The present results indicate that the role of A. israelii in the pathogenesis of osteoradionecrosis of the jaws has not been fully appreciated.« less

Jaw osteonecrosis related to bisphosphonate therapy: a severe secondary disorder.

PubMed

Dannemann, C; Grätz, K W; Riener, M O; Zwahlen, R A

2007-04-01

Bisphosphonate-related osteonecrosis of the jaws (BON), first described in 2003, is gaining importance due to the increasing indication spectrum of bisphosphonate therapy [S. Takeyama, M. Ito, H. Shinoda, A novel bisphosphonate, TRK-530, for periodontitis, Bone 38 (2006) 31-31; M. Tagil, A. W-Dahl, J. Astrand, D. Little, S. Toksvig-Larsen, Decreasing the catabolic response by a single bisphosphonate infusion shortens the healing time in hemicallotasis operations, Bone 38 (2006) 84-85; E. Rodriguez, M.C. Duran, L.M. Rodriguez, R. Ros, M.R. Aleman, M. Rodriguez-Gaspar, A.M. Lopez, E. Garcia-Valdecasas, F. Santolaria, Intravenous (IV) bisphosphonates for osteopenic cancer survivor women: an alternative treatment, Bone 38 (2006) 72-73; D.G. Little, K. Ward, P. Kiely, M.C. Bellemore, J. Briody, C.T. Cowell, Bisphosphonate rescue in distraction osteogenesis: a case series, Bone 38 (2006) 80-80; R. Marx, Pamidronate (Aredia) and zoledronate (Zometa) induced avascular necrosis of the jaws: a growing epidemic, J. Oral Maxillofac. Surg. 61 (2003) 1115-1118]. BON patients suffering from varying bony defects and symptoms are extremely restricted in their quality of life. Due to a limited knowledge of the aetiology of BON efficient evidence-based treatment strategies are lacking. Until now 23 patients with bisphosphonate-related osteonecrosis have been admitted to the Department of Cranio-Maxillofacial Surgery of the University of Zurich. A complete history has been recorded. All patients underwent clinical and radiographic examination. CT scans and MRI have been performed in selected cases. All patients had in common that, before signs of BON were observed, a local traumatic incidence had occurred. All patients showed signs of infection which could be remarkably reduced by antibacterial treatment. Furthermore, the period of bisphosphonate treatment was found to be one of the significant factors causing bisphosphonate-related osteonecrosis of the jaws. The aetiology of BON

[Osteonecrosis of the jaws (ONJ) associated to antiresorptive treatment].

PubMed

Larsson Wexell, Cecilia; Kjellman, Anders; Akre, Olof

2018-05-25

Osteonecrosis of the jaws (ONJ) has been associated to antiresorptive treatment and is an increasing problem all over the world. ONJ is a severe adverse effect of antiresorptive treatment with bisphosphonate and denosumab used for treatment of osteoporosis, metastases from certain malignant conditions and as an adjuvant treatment in postmenopausal women with breast cancer, and of treatment with certain chemotherapeutic drugs. In this paper the epidemiology, symptoms, diagnostic features, clinical findings, and treatment are reviewed. Guidelines are presented for dental treatment, surgery and referral of patients on antiresorptive treatment.

Do patients with chronic unilateral orofacial pain due to a temporomandibular disorder show increased attending to somatosensory input at the painful side of the jaw?

PubMed

Van Damme, Stefaan; Vanden Bulcke, Charlotte; Van Den Berghe, Linda; Poppe, Louise; Crombez, Geert

2018-01-01

Patients with chronic orofacial pain due to temporomandibular disorders (TMD) display alterations in somatosensory processing at the jaw, such as amplified perception of tactile stimuli, but the underlying mechanisms remain unclear. This study investigated one possible explanation, namely hypervigilance, and tested if TMD patients with unilateral pain showed increased attending to somatosensory input at the painful side of the jaw. TMD patients with chronic unilateral orofacial pain ( n  = 20) and matched healthy volunteers ( n  = 20) performed a temporal order judgment (TOJ) task indicated which one of two tactile stimuli, presented on each side of the jaw, they had perceived first. TOJ methodology allows examining spatial bias in somatosensory processing speed. Furthermore, after each block of trials, the participants rated the perceived intensity of tactile stimuli separately for both sides of the jaw. Finally, questionnaires assessing pain catastrophizing, fear-avoidance beliefs, and pain vigilance, were completed. TMD patients tended to perceive tactile stimuli at the painful jaw side as occurring earlier in time than stimuli at the non-painful side but this effect did not reach conventional levels of significance ( p  = .07). In the control group, tactile stimuli were perceived as occurring simultaneously. Secondary analyses indicated that the magnitude of spatial bias in the TMD group is positively associated with the extent of fear-avoidance beliefs. Overall, intensity ratings of tactile stimuli were significantly higher in the TMD group than in the control group, but there was no significant difference between the painful and non-painful jaw side in the TMD patients. The hypothesis that TMD patients with chronic unilateral orofacial pain preferentially attend to somatosensory information at the painful side of the jaw was not statistically supported, although lack of power could not be ruled out as a reason for this. The findings are discussed within

Intraosseous embolotherapy of central arteriovenous malformations in the jaw: long-term experience with 8 cases.

PubMed

Liu, Denggao; Ma, Xuchen; Zhao, Fuyun; Zhang, Jianguo

2009-11-01

To investigate the long-term effects of direct intraosseous histoacryl embolotherapy on central arteriovenous malformations (AVMs) of the jaw. Eight patients with central AVMs of the jaw (3 in the maxilla and 5 in the mandible) were treated with direct intraosseous histoacryl injection. These AVMs exhibited cystic radiolucency, with (n = 5) or without (n = 3) honeycombed component. On angiography, all the AVMs exhibited a large intraosseous nidus with multiple suppliers and drainages. The intraosseous lesions were percutaneously punctured with an 18- to 20-gauge needle, and NBCA diluted 30% to 40% with iodized oil was injected during venous compression. Postembolic arteriograms showed that all the AVMs were completely or nearly completely devascularized after single or multiple injections at the initial treatment. The follow-up period ranged from 3 to 8 years. Two AVMs experienced postembolic curettage and were anatomically cured. Three AVMs were anatomically cured after 1 to 3 sessions of embolotherapy. The other 3 AVMs were clinically cured after 1 (n = 2) to 4 (n = 1) sessions of embolotherapy. There were no procedure-related severe complications. Direct intraosseous glue embolotherapy can be a simple and safe technique for endovascular management of central AVMs in the jaw and is particularly effective in an emergency. Complete reossification of the intraosseous nidus can be anticipated if a complete occlusion is obtained.

Is Virtual Surgical Planning in Orthognathic Surgery Faster Than Conventional Planning? A Time and Workflow Analysis of an Office-Based Workflow for Single- and Double-Jaw Surgery.

PubMed

Steinhuber, Thomas; Brunold, Silvia; Gärtner, Catherina; Offermanns, Vincent; Ulmer, Hanno; Ploder, Oliver

2018-02-01

The purpose of this study was to measure and compare the working time for virtual surgical planning (VSP) in orthognathic surgery in a largely office-based workflow in comparison with conventional surgical planning (CSP) regarding the type of surgery, staff involved, and working location. This prospective cohort study included patients treated with orthognathic surgery from May to December 2016. For each patient, both CSP with manual splint fabrication and VSP with fabrication of computer-aided design-computer-aided manufacturing splints were performed. The predictor variables were planning method (CSP or VSP) and type of surgery (single or double jaw), and the outcome was time. Descriptive and analytic statistics, including analysis of variance for repeated measures, were computed. The sample was composed of 40 patients (25 female and 15 male patients; mean age, 24.6 years) treated with single-jaw surgery (n = 18) or double-jaw surgery (n = 22). The mean times for planning single-jaw surgery were 145.5 ± 11.5 minutes for CSP and 109.3 ± 10.8 minutes for VSP, and those for planning double-jaw surgery were 224.1 ± 11.2 minutes and 149.6 ± 15.3 minutes, respectively. Besides the expected result that the working time was shorter for single-versus double-jaw surgery (P < .001), it was shown that VSP shortened the working time significantly versus CSP (P < .001). The reduction of time through VSP was relatively stronger for double-jaw surgery (P < .001 for interaction). All differences between CSP and VSP regarding profession (except for the surgeon's time investment) and location were statistically significant (P < .01). The surgeon's time to plan single-jaw surgery was 37.0 minutes for CSP and 41.2 minutes for VSP; for double-jaw surgery, it was 53.8 minutes and 53.6 minutes, respectively. Office-based VSP for orthognathic surgery was significantly faster for single- and double-jaw surgery. The time investment of the surgeon was equal

3D-model building of the jaw impression

NASA Astrophysics Data System (ADS)

Ahmed, Moumen T.; Yamany, Sameh M.; Hemayed, Elsayed E.; Farag, Aly A.

1997-03-01

A novel approach is proposed to obtain a record of the patient's occlusion using computer vision. Data acquisition is obtained using intra-oral video cameras. The technique utilizes shape from shading to extract 3D information from 2D views of the jaw, and a novel technique for 3D data registration using genetic algorithms. The resulting 3D model can be used for diagnosis, treatment planning, and implant purposes. The overall purpose of this research is to develop a model-based vision system for orthodontics to replace traditional approaches. This system will be flexible, accurate, and will reduce the cost of orthodontic treatments.

Assessment of the Survival of Dental Implants in Irradiated Jaws Following Treatment of Oral Cancer: A Retrospective Study

PubMed Central

Rana, Meenakshi Chauhan; Solanki, Swati; Pujari, Sudarshan C; Shaw, Eisha; Sharma, Swati; Anand, Abhishek; Singh, Harkanwal Preet

2016-01-01

Background: In patients undergoing head and neck surgery for various pathologic conditions, implants are one of the best restorative options and are increasing widely used. Therefore, we evaluated the success of dental implants in the irradiated jaws of patients following treatment of oral cancer oral cancer treated patients. Materials and Methods: Data of oral cancer treated patients was collected retrospectively from 2002 to 2008. We took 46 oral cancer treated patients in which implants were placed in irradiated jaws for rehabilitation. Results: It was found that out of 162 dental implants placed, 52 failed. Furthermore, there was no variation in the implant survival rate in between both the jaws. Radiation dose of <50 Gy units also showed significantly increased amount of implant survival rate. Conclusions: Implant survival is multifactorial and depends upon a number of factors like level of radiation exposure in that area, time gap between last radiation doses etc., Further research is required in this field to improve the esthetics and quality of life of cancer treated patients. PMID:27843270

SU-F-E-20: A Mathematical Model of Linac Jaw Calibration Integrated with Collimator Walkout

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Y; Corns, R; Huang, V

2016-06-15

Purpose: Accurate jaw calibration is possible, but it does not necessarily achieve good junctions because of collimator rotation walkout. We developed a mathematical model seeking to pick an origin for calibration that minimizes the collimator walkout effect. Methods: We use radioopaque markers aligned with crosshair on the EPID to determine the collimator walkout at collimator angles 0°, 90° and 270°. We can accurately calibrate jaws to any arbitrary origin near the radiation field centre. While the absolute position of an origin moves with the collimator walkout, its relative location to the crosshair is an invariant. We studied two approaches tomore » select an optimal origin. One approach seeks to bring all three origin locations (0°–90°–270°) as close as possible by minimizing the perimeter of the triangle formed by these points. The other approach focuses on the gap for 0°–90° junctions. Results: Our perimeter cost function has two variables and non-linear behaviour. Generally, it does not have zero-perimeter-length solution which leads to perfect jaw matches. The zero solution can only be achieved, if the collimator rotates about a single fixed axis. In the second approach, we can always get perfect 0°–0° and 0°–90° junctions, because we ignore the 0°–270° situation. For our TrueBeams, both techniques for selecting an origin improved junction dose inhomogeneities to less than ±6%. Conclusion: Our model considers the general jaw matching with collimator rotations and proposes two potential solutions. One solution optimizes the junction gaps by considering all three collimator angles while the other only considers 0°–90°. The first solution will not give perfect matching, but can be clinically acceptable with minimized collimator walkout effect, while the second can have perfect junctions at the expense of the 0°–270° junctions. Different clinics might choose between these two methods basing on their clinical practices.« less

Accuracy of Intraoral Digital Impressions for Whole Upper Jaws, Including Full Dentitions and Palatal Soft Tissues.

PubMed

Gan, Ning; Xiong, Yaoyang; Jiao, Ting

2016-01-01

Intraoral digital impressions have been stated to meet the clinical requirements for some teeth-supported restorations, though fewer evidences were proposed for larger scanning range. The aim of this study was to compare the accuracy (trueness and precision) of intraoral digital impressions for whole upper jaws, including the full dentitions and palatal soft tissues, as well as to determine the effect of different palatal vault height or arch width on accuracy of intraoral digital impressions. Thirty-two volunteers were divided into three groups according to the palatal vault height or arch width. Each volunteer received three scans with TRIOS intraoral scanner and one conventional impression of whole upper jaw. Three-dimensional (3D) images digitized from conventional gypsum casts by a laboratory scanner were chose as the reference models. All datasets were imported to a specific software program for 3D analysis by "best fit alignment" and "3D compare" process. Color-coded deviation maps showed qualitative visualization of the deviations. For the digital impressions for palatal soft tissues, trueness was (130.54±33.95)μm and precision was (55.26±11.21)μm. For the digital impressions for upper full dentitions, trueness was (80.01±17.78)μm and precision was (59.52±11.29)μm. Larger deviations were found between intraoral digital impressions and conventional impressions in the areas of palatal soft tissues than that in the areas of full dentitions (p<0.001). Precision of digital impressions for palatal soft tissues was slightly better than that for full dentitions (p = 0.049). There was no significant effect of palatal vault height on accuracy of digital impressions for palatal soft tissues (p>0.05), but arch width was found to have a significant effect on precision of intraoral digital impressions for full dentitions (p = 0.016). A linear correlation was found between arch width and precision of digital impressions for whole upper jaws (r = 0.326, p = 0

Osteonecrosis of the jaw: effect of bisphosphonate type, local concentration, and acidic milieu on the pathomechanism.

PubMed

Otto, Sven; Pautke, Christoph; Opelz, Christine; Westphal, Ines; Drosse, Inga; Schwager, Joanna; Bauss, Frieder; Ehrenfeld, Michael; Schieker, Matthias

2010-11-01

Osteonecrosis of the jaw has been reported in patients receiving high doses of intravenous nitrogen-containing bisphosphonates (N-BPs) because of malignant disease. The exact pathomechanisms have been elusive and questions of paramount importance remain unanswered. Recent studies have indicated toxic effects of bisphosphonates on different cell types, apart from osteoclast inhibition. Multipotent stem cells play an important role in the processes of wound healing and bone regeneration, which seem to be especially impaired in the jaws of patients receiving high doses of N-BPs. Therefore, the aim of the present study was to investigate the effects of different bisphosphonate derivatives and dose levels combined with varying pH levels on the mesenchymal stem cells in vitro. The effect of 2 N-BPs (zoledronate and ibandronate) and 1 non-N-BP (clodronate) on immortalized mesenchymal stem cells was tested at different concentrations, reflecting 1, 3, and 6 months and 1, 3, 5, and 10 years of exposure to standard oncology doses of the 2 N-BPs and equimolar concentrations of clodronate at different pH values (7.4, 7.0, 6.7, and 6.3). Cell viability and activity were analyzed using a WST assay. Cell motility was investigated using scratch wound assays and visualized using time-lapse microscopy. Both types of bisphosphonates revealed remarkable differences. Zoledronate and ibandronate showed a dose- and pH-dependent cellular toxicity. Increasing concentrations of both N-BPs and an acidic milieu led to a significant decrease in cell viability and activity (P < .01), with more pronounced effects for zoledronate. Equimolar concentrations of clodronate did not affect the cell survival or activity significantly, apart from the effect of pH reduction itself, which was also detectable in the patients in the control group who did not receive bisphosphonates. Our results have shown that high concentrations of N-BPs and a local acidic milieu, which is commonly present in infections of

Accuracy of Intraoral Digital Impressions for Whole Upper Jaws, Including Full Dentitions and Palatal Soft Tissues

PubMed Central

Gan, Ning; Xiong, Yaoyang; Jiao, Ting

2016-01-01

Intraoral digital impressions have been stated to meet the clinical requirements for some teeth-supported restorations, though fewer evidences were proposed for larger scanning range. The aim of this study was to compare the accuracy (trueness and precision) of intraoral digital impressions for whole upper jaws, including the full dentitions and palatal soft tissues, as well as to determine the effect of different palatal vault height or arch width on accuracy of intraoral digital impressions. Thirty-two volunteers were divided into three groups according to the palatal vault height or arch width. Each volunteer received three scans with TRIOS intraoral scanner and one conventional impression of whole upper jaw. Three-dimensional (3D) images digitized from conventional gypsum casts by a laboratory scanner were chose as the reference models. All datasets were imported to a specific software program for 3D analysis by "best fit alignment" and "3D compare" process. Color-coded deviation maps showed qualitative visualization of the deviations. For the digital impressions for palatal soft tissues, trueness was (130.54±33.95)μm and precision was (55.26±11.21)μm. For the digital impressions for upper full dentitions, trueness was (80.01±17.78)μm and precision was (59.52±11.29)μm. Larger deviations were found between intraoral digital impressions and conventional impressions in the areas of palatal soft tissues than that in the areas of full dentitions (p<0.001). Precision of digital impressions for palatal soft tissues was slightly better than that for full dentitions (p = 0.049). There was no significant effect of palatal vault height on accuracy of digital impressions for palatal soft tissues (p>0.05), but arch width was found to have a significant effect on precision of intraoral digital impressions for full dentitions (p = 0.016). A linear correlation was found between arch width and precision of digital impressions for whole upper jaws (r = 0.326, p = 0

Platelet Lysate: The Better Choice for Jaw Periosteal Cell Mineralization

PubMed Central

Wanner, Yvonne; Umrath, Felix; Waidmann, Marc; Reinert, Siegmar

2017-01-01

Previously, we demonstrated a high quality of minerals formed by serum-free cultured jaw periosteal cells (JPCs) by Raman spectroscopy but the mineralization extent was not satisfactory. In the present study, we analyzed the proliferation and mineralization potential of human platelet lysate- (hPL-) cultured JPCs in comparison to that of FCS-cultured JPCs. By cell impedance measurements, we detected significantly higher population doubling times of PL-cultured JPCs in comparison to FCS-cultured JPCs. However, this result was not based on lower proliferation activities but on diminished cell sizes which JPCs develop under PL cultivation. The measurements of the metabolic activities clearly showed significantly higher cell proliferation rates under PL culturing. Equivalent levels of the mesenchymal cell markers CD29, CD45, CD73, CD90, and CD105 were detected, but there were significantly increased MSCA-1 levels under PL cultivation. While JPCs only occasionally mineralize under FCS culture conditions, the mineralization potential was significantly stronger under PL cultivation. Moreover, in 4 of 5 analyzed patient cells, the addition of dexamethasone was proved no longer necessary for strong mineralization of PL-cultured JPCs. We conclude that in vitro cultivation of JPCs with platelet lysate is a suitable alternative to FCS culture conditions and a powerful tool for the development of high-quality TE constructs using jaw periosteal cells. PMID:29391870

Platelet Lysate: The Better Choice for Jaw Periosteal Cell Mineralization.

PubMed

Wanner, Yvonne; Umrath, Felix; Waidmann, Marc; Reinert, Siegmar; Alexander, Dorothea

2017-01-01

Previously, we demonstrated a high quality of minerals formed by serum-free cultured jaw periosteal cells (JPCs) by Raman spectroscopy but the mineralization extent was not satisfactory. In the present study, we analyzed the proliferation and mineralization potential of human platelet lysate- (hPL-) cultured JPCs in comparison to that of FCS-cultured JPCs. By cell impedance measurements, we detected significantly higher population doubling times of PL-cultured JPCs in comparison to FCS-cultured JPCs. However, this result was not based on lower proliferation activities but on diminished cell sizes which JPCs develop under PL cultivation. The measurements of the metabolic activities clearly showed significantly higher cell proliferation rates under PL culturing. Equivalent levels of the mesenchymal cell markers CD29, CD45, CD73, CD90, and CD105 were detected, but there were significantly increased MSCA-1 levels under PL cultivation. While JPCs only occasionally mineralize under FCS culture conditions, the mineralization potential was significantly stronger under PL cultivation. Moreover, in 4 of 5 analyzed patient cells, the addition of dexamethasone was proved no longer necessary for strong mineralization of PL-cultured JPCs. We conclude that in vitro cultivation of JPCs with platelet lysate is a suitable alternative to FCS culture conditions and a powerful tool for the development of high-quality TE constructs using jaw periosteal cells.

Convergent evolution of hemoglobin switching in jawed and jawless vertebrates.

PubMed

Rohlfing, Kim; Stuhlmann, Friederike; Docker, Margaret F; Burmester, Thorsten

2016-02-01

During development, humans and other jawed vertebrates (Gnathostomata) express distinct hemoglobin genes, resulting in different hemoglobin tetramers. Embryonic and fetal hemoglobin have higher oxygen affinities than the adult hemoglobin, sustaining the oxygen demand of the developing organism. Little is known about the expression of hemoglobins during development of jawless vertebrates (Agnatha). We identified three hemoglobin switches in the life cycle of the sea lamprey. Three hemoglobin genes are specifically expressed in the embryo, four genes in the filter feeding larva (ammocoete), and nine genes correspond to the adult hemoglobin chains. During the development from the parasitic to the reproductive adult, the composition of hemoglobin changes again, with a massive increase of chain aHb1. A single hemoglobin chain is expressed constitutively in all stages. We further showed the differential expression of other globin genes: Myoglobin 1 is most highly expressed in the reproductive adult, myoglobin 2 expression peaks in the larva. Globin X1 is restricted to the embryo; globin X2 was only found in the reproductive adult. Cytoglobin is expressed at low levels throughout the life cycle. Because the hemoglobins of jawed and jawless vertebrates evolved independently from a common globin ancestor, hemoglobin switching must also have evolved convergently in these taxa. Notably, the ontogeny of sea lamprey hemoglobins essentially recapitulates their phylogeny, with the embryonic hemoglobins emerging first, followed by the evolution of larval and adult hemoglobins.

Automatic repositioning of jaw segments for three-dimensional virtual treatment planning of orthognathic surgery.

PubMed

Santos, Rodrigo Mologni Gonçalves Dos; De Martino, José Mario; Passeri, Luis Augusto; Attux, Romis Ribeiro de Faissol; Haiter Neto, Francisco

2017-09-01

To develop a computer-based method for automating the repositioning of jaw segments in the skull during three-dimensional virtual treatment planning of orthognathic surgery. The method speeds up the planning phase of the orthognathic procedure, releasing surgeons from laborious and time-consuming tasks. The method finds the optimal positions for the maxilla, mandibular body, and bony chin in the skull. Minimization of cephalometric differences between measured and standard values is considered. Cone-beam computed tomographic images acquired from four preoperative patients with skeletal malocclusion were used for evaluating the method. Dentofacial problems of the four patients were rectified, including skeletal malocclusion, facial asymmetry, and jaw discrepancies. The results show that the method is potentially able to be used in routine clinical practice as support for treatment-planning decisions in orthognathic surgery. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Osteonecrosis of the jaw (ONJ) in patients who receive Bone Targeting Agents (BTAs): the power of e-learning.

PubMed

Nicolatou-Galitis, Ourania; Migliorati, Cesar

2018-01-01

The definition, pathobiology and risk factors of ONJ in cancer patients who receive BTAs are discussed in the recent ecancer module for osteonecrosis of the jaw (http://ecancer.org/education/module/276-osteonecrosis-of-the-jaw.php). ONJ prevention, early diagnosis and management are presented. The critical question of the performance of dental extraction, during BTA therapy, as indicated with the recent studies, is supported. The importance of the collaboration between dental and oncology professionals and the patients is highlighted and can be achieved through appropriate education. The ecancer modules are valuable tools for successful e-learning in medical oncology education, including ONJ.

Osteomalacia: the missing link in the pathogenesis of bisphosphonate-related osteonecrosis of the jaws?

PubMed

Bedogni, Alberto; Saia, Giorgia; Bettini, Giordana; Tronchet, Anita; Totola, Andrea; Bedogni, Giorgio; Tregnago, Paolo; Valenti, Maria Teresa; Bertoldo, Francesco; Ferronato, Giuseppe; Nocini, Pier Francesco; Blandamura, Stella; Dalle Carbonare, Luca

2012-01-01

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a well-documented adverse event from treatment with nitrogen-containing bisphosphonates (NBPs). During a preliminary histomorphometric study aimed at assessing the rate of bone remodeling in the jaws of patients with surgically resected BRONJ, we found a defect of bone mineralization (unpublished data). We hypothesized that osteomalacia could be a risk factor for BRONJ in patients taking NBPs. Therefore, we looked for static and dynamic histomorphometric evidence of osteomalacia in biopsies from subjects with and without BRONJ. This case-control study used histomorphometric analysis of bone specimens of patients using NBPs (22 patients with BRONJ and 21 patients without BRONJ) who required oral surgical interventions for the treatment/prevention of osteonecrosis. Patients were given tetracycline hydrochloride according to a standardized protocol before taking bone biopsies from their jaws. Biopsies with evidence of osteomyelitis or necrosis at histology were excluded from the study. Osteomalacia was defined as a mineralization lag time >100 days, a corrected mean osteoid thickness >12.5 mm, and an osteoid volume >10%. In all, 77% of patients with BRONJ were osteomalacic compared with 5% of patients without BRONJ, according to histomorphometry. Because osteomalacia was found almost exclusively in NBP users with BRONJ, this is likely to be a generalized process in which the use of NBPs further deteriorates mechanisms of bone repair. Osteomalacia represents a new and previously unreported risk factor for disease development. This finding may contribute to a better understanding of the pathogenesis of this disease and help with the development of strategies to increase the safety of NBP administration.

The genetic architecture of novel trophic specialists: larger effect sizes are associated with exceptional oral jaw diversification in a pupfish adaptive radiation.

PubMed

Martin, Christopher H; Erickson, Priscilla A; Miller, Craig T

2017-01-01

The genetic architecture of adaptation is fundamental to understanding the mechanisms and constraints governing diversification. However, most case studies focus on loss of complex traits or parallel speciation in similar environments. It is still unclear how the genetic architecture of these local adaptive processes compares to the architecture of evolutionary transitions contributing to morphological and ecological novelty. Here, we identify quantitative trait loci (QTL) between two trophic specialists in an excellent case study for examining the origins of ecological novelty: a sympatric radiation of pupfishes endemic to San Salvador Island, Bahamas, containing a large-jawed scale-eater and a short-jawed molluscivore with a skeletal nasal protrusion. These specialized niches and trophic traits are unique among over 2000 related species. Measurements of the fitness landscape on San Salvador demonstrate multiple fitness peaks and a larger fitness valley isolating the scale-eater from the putative ancestral intermediate phenotype of the generalist, suggesting that more large-effect QTL should contribute to its unique phenotype. We evaluated this prediction using an F2 intercross between these specialists. We present the first linkage map for pupfishes and detect significant QTL for sex and eight skeletal traits. Large-effect QTL contributed more to enlarged scale-eater jaws than the molluscivore nasal protrusion, consistent with predictions from the adaptive landscape. The microevolutionary genetic architecture of large-effect QTL for oral jaws parallels the exceptional diversification rates of oral jaws within the San Salvador radiation observed over macroevolutionary timescales and may have facilitated exceptional trophic novelty in this system. © 2016 John Wiley & Sons Ltd.

Effects of Botulinum Toxin on Jaw Motor Events during Sleep in Sleep Bruxism Patients: A Polysomnographic Evaluation

PubMed Central

Shim, Young Joo; Lee, Moon Kyu; Kato, Takafumi; Park, Hyung Uk; Heo, Kyoung; Kim, Seong Taek

2014-01-01

Study Objectives: To investigate the effects of botulinum toxin type A (BoNT-A) injection on jaw motor episodes during sleep in patients with or without orofacial pain who did not respond to oral splint treatment. Methods: Twenty subjects with a clinical diagnosis of SB completed this study. Ten subjects received bilateral BoNT-A injections (25 U per muscle) into the masseter muscles only (group A), and the other 10 received the injections into both the masseter and temporalis muscles (group B). Video-polysomnographic (vPSG) recordings were made before and at 4 weeks after injection. Rhythmic masticatory muscle activity (RMMA) and orofacial activity (OFA) were scored and analyzed for several parameters (e.g., frequency of episodes, bursts per episode, episode duration). The peak amplitude of electromyographic (EMG) activity in the two muscles was also measured. Results: BoNT-A injection did not reduce the frequency, number of bursts, or duration for RMMA episodes in the two groups. The injection decreased the peak amplitude of EMG burst of RMMA episodes in the injected muscles (p < 0.001, repeated measure ANOVA) in both groups. At 4 weeks after injection, 9 subjects self-reported reduction of tooth grinding and 18 subjects self-reported reduction of morning jaw stiffness. Conclusions: A single BoNT-A injection is an effective strategy for controlling SB for at least a month. It reduces the intensity rather than the generation of the contraction in jaw-closing muscles. Future investigations on the efficacy and safety in larger samples over a longer follow-up period are needed before establishing management strategies for SB with BoNT-A. Citation: Shim YJ; Lee MK; Kato T; Park HU; Heo K; Kim ST. Effects of botulinum toxin on jaw motor events during sleep in sleep bruxism patients: a polysomnographic evaluation. J Clin Sleep Med 2014;10(3):291-298. PMID:24634627

A suitable device for cystic lesions close to the tooth-bearing areas of the jaws.

PubMed

Costa, Fábio Wildson Gurgel; Carvalho, Francisco Samuel Rodrigues; Chaves, Filipe Nobre; Soares, Eduardo Costa Studart

2014-01-01

Different devices for decompression of cystic lesions of the jaw have been described in the literature. Although there are no rigorous rules for choosing a particular design or method, the choice depends on situational needs. Although minor, most techniques are associated with certain difficulties and complications, such as the need for long-term monitoring, inappropriate decompression tube size, soft tissue trauma, suture dehiscence, soft tissue invagination, dislodgement, and malpositioning of the tube into the lesion. These complications may have a negative impact on the level of treatment acceptance, especially when devices are used over long periods. The aim of this study was to present a new suitable device for cystic lesions close to tooth-bearing areas of the jaws. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

THE INFLUENCE OF LEXICAL FACTORS ON VOWEL DISTINCTIVENESS: EFFECTS OF JAW POSITIONING.

PubMed

Munson, Benjamin; Solomon, Nancy Pearl

2016-11-01

The phonetic characteristics of words are influenced by lexical characteristics, including word frequency and phonological neighborhood density (Baese-Berke & Goldrick, 2009; Wright, 2004). In our previous research, we replicated this effect with neurologically healthy young adults (Munson & Solomon, 2004). In research with the same set of participants, we showed that speech sounded less natural when produced with bite blocks than with an unconstrained jaw (Solomon, Makashay, & Munson, 2016). The current study combined these concepts to examine whether a bite-block perturbation exaggerated or reduced the effects of lexical factors on normal speech. Ten young adults produced more challenging lexical stimuli (i.e. infrequent words with many phonological neighbors) with shorter vowels and more disperse F1/F2 spaces than less challenging words (i.e. frequent words with few phonological neighbors). This difference was exaggerated when speaking with a 10-mm bite block, though the interaction between jaw positioning and lexical competition did not achieve statistical significance. Results indicate that talkers alter vowel characteristics in response both to biomechanical and linguistic demands, and that the effect of lexical characteristics is robust to the articulatory reorganization required for successful bite-block compensation.

Variation in the shape and mechanical performance of the lower jaws in ceratopsid dinosaurs (Ornithischia, Ceratopsia).

PubMed

Maiorino, Leonardo; Farke, Andrew A; Kotsakis, Tassos; Teresi, Luciano; Piras, Paolo

2015-11-01

Ceratopsidae represents a group of quadrupedal herbivorous dinosaurs that inhabited western North America and eastern Asia during the Late Cretaceous. Although horns and frills of the cranium are highly variable across species, the lower jaw historically has been considered to be relatively conservative in morphology. Here, the lower jaws from 58 specimens representing 21 ceratopsoid taxa were sampled, using geometric morphometrics and 2D finite element analysis (FEA) to explore differences in morphology and mechanical performance across Ceratopsoidea (the clade including Ceratopsidae, Turanoceratops and Zuniceratops). Principal component analyses and non-parametric permuted manovas highlight Triceratopsini as a morphologically distinct clade within the sample. A relatively robust and elongate dentary, a larger and more elongated coronoid process, and a small and dorso-ventrally compressed angular characterize this clade, as well as the absolutely larger size. By contrast, non-triceratopsin chasmosaurines, Centrosaurini and Pachyrhinosaurini have similar morphologies to each other. Zuniceratops and Avaceratops are distinct from other taxa. No differences in size between Pachyrhinosaurini and Centrosaurini are recovered using non-parametric permuted anovas. Structural performance, as evaluated using a 2D FEA, is similar across all groups as measured by overall stress, with the exception of Triceratopsini. Shape, size and stress are phylogenetically constrained. A longer dentary as well as a long coronoid process result in a lower jaw that is reconstructed as relatively much more stressed in triceratopsins. © 2015 Anatomical Society.

Multiple prismatic calcium phosphate layers in the jaws of present-day sharks (Chondrichthyes; Selachii).

PubMed

Dingerkus, G; Séret, B; Guilbert, E

1991-01-15

Jaws of large individuals, over 2 m in total length, of the shark species Carcharodon carcharias (great white shark) and Isurus oxyrinchus (mako shark) of the family Lamnidae, and Galeocerdo cuvieri (tiger shark) and Carcharhinus leucas (bull shark) of the family Carcharhinidae were found to have multiple, up to five, layers of prismatic calcium phosphate surrounding the cartilages. Smaller individuals of these species and other known species of living chondrichthyans have only one layer of prismatic calcium phosphate surrounding the cartilages, as also do most species of fossil chondrichthyans. Two exceptions are the fossil shark genera Xenacanthus and Tamiobatis. Where it is found in living forms, this multiple layered calcification does not appear to be phylogenetic, as it appears to be lacking in other lamnid and carcharhinid genera and species. Rather it appears to be functional, only appearing in larger individuals and species of these two groups, and hence may be necessary to strengthen the jaw cartilages of such individuals for biting.

Standardized classification unsuitable for spontaneous reporting: the example of osteonecrosis of the jaw.

PubMed

de Boissieu, Paul; Trenque, Thierry

2015-07-01

This study assessed the impact of using a standardized definition of bisphosphonate-related osteonecrosis of the jaw (BRONJ) in the analysis of a spontaneous reporting database. All notifications of osteonecrosis of the jaw (ONJ) in the French National Pharmacovigilance Database as of 31 December 2013 were analyzed. First, we considered all reports of ONJ with bisphosphonates as BRONJ. Second, we applied the 2014 definition of BRONJ from the American Association of Oral and Maxillofacial Surgeons (AAOMS), retaining only bisphosphonates as antiresorptive medication. In the absence of any one of these criteria, or missing data, cases were not considered as BRONJ. The first analysis found 158 cases of ONJ, among which 153 were associated with bisphosphonate use. The second analysis identified only 43 cases of BRONJ (28.1%). The definition of BRONJ as laid down by the AAOMS is not suitable for use in spontaneous reporting database. The use of the AAOMS definition alone should be avoided, as it leads to the exclusion of over 70% of cases. When cases of ONJ are identified, all results should be presented including confirmed and excluded cases.

Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) Slit-Jaw Imaging System

NASA Astrophysics Data System (ADS)

Wilkerson, P.; Champey, P. R.; Winebarger, A. R.; Kobayashi, K.; Savage, S. L.

2017-12-01

The Marshall Grazing Incidence X-ray Spectrometer is a NASA sounding rocket payload providing a 0.6 - 2.5 nm spectrum with unprecedented spatial and spectral resolution. The instrument is comprised of a novel optical design, featuring a Wolter1 grazing incidence telescope, which produces a focused solar image on a slit plate, an identical pair of stigmatic optics, a planar diffraction grating and a low-noise detector. When MaGIXS flies on a suborbital launch in 2019, a slit-jaw camera system will reimage the focal plane of the telescope providing a reference for pointing the telescope on the solar disk and aligning the data to supporting observations from satellites and other rockets. The telescope focuses the X-ray and EUV image of the sun onto a plate covered with a phosphor coating that absorbs EUV photons, which then fluoresces in visible light. This 10-week REU project was aimed at optimizing an off-axis mounted camera with 600-line resolution NTSC video for extremely low light imaging of the slit plate. Radiometric calculations indicate an intensity of less than 1 lux at the slit jaw plane, which set the requirement for camera sensitivity. We selected a Watec 910DB EIA charge-coupled device (CCD) monochrome camera, which has a manufacturer quoted sensitivity of 0.0001 lux at F1.2. A high magnification and low distortion lens was then identified to image the slit jaw plane from a distance of approximately 10 cm. With the selected CCD camera, tests show that at extreme low-light levels, we achieve a higher resolution than expected, with only a moderate drop in frame rate. Based on sounding rocket flight heritage, the launch vehicle attitude control system is known to stabilize the instrument pointing such that jitter does not degrade video quality for context imaging. Future steps towards implementation of the imaging system will include ruggedizing the flight camera housing and mounting the selected camera and lens combination to the instrument structure.

Stress distribution in the temporo-mandibular joint discs during jaw closing: a high-resolution three-dimensional finite-element model analysis.

PubMed

Savoldelli, Charles; Bouchard, Pierre-Olivier; Loudad, Raounak; Baque, Patrick; Tillier, Yannick

2012-07-01

This study aims at analysing the stresses distribution in the temporomandibular joint (TMJ) using a complete high-resolution finite element model (FE Model). This model is used here to analyse the stresses distribution in the discs during a closing jaw cycle. In the end, this model enables the prediction of the stress evolution in the TMJ disc submitted to various loadings induced by mandibular trauma, surgery or parafunction. The geometric data for the model were obtained from MRI and CT scans images of a healthy male patient. Surface and volume meshes were successively obtained using a 3D image segmentation software (AMIRA(®)). Bone components of skull and mandible, both of joint discs, temporomandibular capsules and ligaments and dental arches were meshed as separate bodies. The volume meshes were transferred to the FE analysis software (FORGE(®)). Material properties were assigned for each region. Boundary conditions for closing jaw simulations were represented by different load directions of jaws muscles. The von Mises stresses distribution in both joint discs during closing conditions was analyzed. The pattern of von Mises stresses in the TMJ discs is non-symmetric and changed continuously during jaw movement. Maximal stress is reached on the surface disc in areas in contact with others bodies. The three-dimension finite element model of masticatory system will make it possible to simulate different conditions that appear to be important in the cascade of events leading to joint damage.

Development of Flight Slit-Jaw Optics for Chromospheric Lyman-Alpha SpectroPolarimeter

NASA Technical Reports Server (NTRS)

Kubo, Masahito; Suematsu, Yoshinori; Kano, Ryohei; Bando, Takamasa; Hara, Hirohisa; Narukage, Noriyuki; Katsukawa, Yukio; Ishikawa, Ryoko; Ishikawa, Shin-nosuke; Kobiki, Toshihiko;

Development of Flight Slit-Jaw Optics for Chromospheric Lyman-Alpha SpectroPolarimeter

NASA Technical Reports Server (NTRS)

Kubo, Masahito; Suematsu, Yoshinori; Kano, Ryohei; Bando, Takamasa; Hara, Hirohisa; Narukage, Noriyuki; Katsukawa, Yukio; Ishikawa, Ryoko; Ishikawa, Shin-nosuke; Kobiki, Toshihiko;

Osteomalacia: The Missing Link in the Pathogenesis of Bisphosphonate-Related Osteonecrosis of the Jaws?

PubMed Central

Saia, Giorgia; Bettini, Giordana; Tronchet, Anita; Totola, Andrea; Bedogni, Giorgio; Tregnago, Paolo; Valenti, Maria Teresa; Bertoldo, Francesco; Ferronato, Giuseppe; Nocini, Pier Francesco; Blandamura, Stella; Dalle Carbonare, Luca

2012-01-01

Background. Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a well-documented adverse event from treatment with nitrogen-containing bisphosphonates (NBPs). During a preliminary histomorphometric study aimed at assessing the rate of bone remodeling in the jaws of patients with surgically resected BRONJ, we found a defect of bone mineralization (unpublished data). We hypothesized that osteomalacia could be a risk factor for BRONJ in patients taking NBPs. Therefore, we looked for static and dynamic histomorphometric evidence of osteomalacia in biopsies from subjects with and without BRONJ. Methods. This case-control study used histomorphometric analysis of bone specimens of patients using NBPs (22 patients with BRONJ and 21 patients without BRONJ) who required oral surgical interventions for the treatment/prevention of osteonecrosis. Patients were given tetracycline hydrochloride according to a standardized protocol before taking bone biopsies from their jaws. Biopsies with evidence of osteomyelitis or necrosis at histology were excluded from the study. Osteomalacia was defined as a mineralization lag time >100 days, a corrected mean osteoid thickness >12.5 mm, and an osteoid volume >10%. Results. In all, 77% of patients with BRONJ were osteomalacic compared with 5% of patients without BRONJ, according to histomorphometry. Because osteomalacia was found almost exclusively in NBP users with BRONJ, this is likely to be a generalized process in which the use of NBPs further deteriorates mechanisms of bone repair. Conclusions. Osteomalacia represents a new and previously unreported risk factor for disease development. This finding may contribute to a better understanding of the pathogenesis of this disease and help with the development of strategies to increase the safety of NBP administration. PMID:22723507

The value of maximum jaw motion measurements for distinguishing between common temporomandibular disorder subgroups.

PubMed

Masumi, S; Kim, Y J; Clark, G T

2002-05-01

The purpose of this study was to determine if mandibular motion measurements could be used to distinguish between common temporomandibular disorder (TMD) subgroups that were established on the basis of only clinical signs and symptoms. Patients were 41 consecutive TMD clinic patients (31 women and 10 men). These patients were divided into 6 typical TMD subgroups. The subgroups were patients with (1) arthromyalgia, (2) arthromyalgia with disk condyle incoordination, (3) disk condyle incoordination only, (4) osteoarthritis, (5) suspected disk displacement without reduction, or (6) other diagnoses. There were no subjects in the other-diagnosis subgroup and only 1 subject with suspected disk displacement without reduction who was dropped without further consideration. The data for mean age showed that the osteoarthritis subgroup (n = 12) was statistically older (17 years) than the disk-condyle-incoordination-only subgroup (n = 11). The mean age of the other 2 groups, arthromyalgia (n = 11) and arthromyalgia with disk condyle incoordination (n = 6), was between the osteoarthritis and the disk-condyle-incoordination-only subgroups. For the 4 TMD subgroups whose data were analyzed, the mean differences between similar jaw opening measurements ranged from 6 to 8 mm with a standard deviation of approximately 8 to 10 mm. The mean left lateral motions were 0.5 to 1.3 mm larger than observed on the right. The widest mean jaw opening (56 mm) occurred in the disk-condyle-incoordination-only group. These differences were not found to be statistically significant. Analysis of opening, lateral and protrusive jaw motion data showed these measurements could not reliably differentiate between patients with osteoarthritis, arthromyalgia, arthromyalgia with disk condyle incoordination and disk condyle incoordination only.

Robot gripper

NASA Technical Reports Server (NTRS)

Webb, Winston S. (Inventor)

1987-01-01

An electronic force-detecting robot gripper for gripping objects and attaching to an external robot arm is disclosed. The gripper comprises motor apparatus, gripper jaws, and electrical circuits for driving the gripper motor and sensing the amount of force applied by the jaws. The force applied by the jaws is proportional to a threshold value of the motor current. When the motor current exceeds the threshold value, the electrical circuits supply a feedback signal to the electrical control circuit which, in turn, stops the gripper motor.

Haemangiopericytoma of the jaw.

PubMed

Wushou, Alimujiang; Bai, Xiu Feng; Qi, Hong; Xu, Zhe; Zheng, Jun; Li, Gang

2014-07-01

Haemangiopericytoma (HPC) is a vascular tumour which originates in the pericytes of vessels and therefore it may occur at any site, but it is very uncommon in the jaw. From January 2000 to December 2011, a retrospective analysis of nine consecutive patients with HPCJ was performed. There were five patients with a primary tumour and four patients with a recurrent tumour. Of the nine patients, eight were male and one female. Their ages ranged from 23 years to 51 years, with a median age of 38 years. The tumours were located in the mandible in six patients and in maxilla in three cases. The median course of disease was 7.6 months (range 2-12 months). All patients underwent surgery. Two patients had postoperative adjuvant radiotherapy, and two cases were given postoperative adjuvant chemotherapy. The median follow-up period was 49 months (10-101 months). One patient suffered from lumbar metastasis, while another case had metastasis at local and multiple distant sites, and eventually died. There was no local recurrence or metastasis in other seven cases. HPCJ are rare and the clinical characteristics are not specific. The first choice of treatment is radical surgery. Adjuvant radiotherapy may be effective to improve the prognosis of HPCJ. Copyright © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Functional anatomy and kinematics of the oral jaw system during terrestrial feeding in Periophthalmus barbarus.

PubMed

Michel, Krijn B; Adriaens, Dominique; Aerts, Peter; Dierick, Manuel; Wassenbergh, Sam Van

2014-10-01

The Atlantic mudskipper, Periophthalmus barbarus, is an amphibious fish that successfully overcomes the numerous physical challenges of capturing prey in a terrestrial environment. However, it is unclear what changes in the morphology and function of the feeding apparatus contribute to the mudskipper's successful transition from aquatic to terrestrial capture of prey. In particular, how does the mudskipper achieve effective prehension of land-based prey using its percomorph feeding apparatus? To address that question, we performed a morphological analysis of the feeding apparatus of P. barbarus based on microcomputed tomography scanning, histological sectioning, and dissections as well as a kinematic analysis based on high-speed video and X-ray video to quantify the movements of the oral jaw apparatus elements. Our results show that the neurocranium remains in a fixed position relative to the pectoral girdle as the fish pivots over its pectoral fins toward the prey. The premaxilla rotates dorsally and protrudes downward over the prey. The dentary is rotated ventrally over an angle of 120°, which is facilitated by an intramandibular joint. These motions of the neurocranium, premaxilla, and dentary reorient the mouth aperture so it is parallel to the substrate, thereby allowing the jaws to be placed over the prey. The prey is grabbed between the oral teeth or scooped into the mouth primarily via rapid closing motion of the lower jaw. This analysis of P. barbarus clarifies the morphological and kinematic characteristics required by fish to become successful terrestrial feeders at the environmental transition between water and land. © 2014 Wiley Periodicals, Inc.

Accuracy of virtual surgical planning in two-jaw orthognathic surgery: comparison of planned and actual results.

PubMed

Zhang, Nan; Liu, Shuguang; Hu, Zhiai; Hu, Jing; Zhu, Songsong; Li, Yunfeng

2016-08-01

This study aims to evaluate the accuracy of virtual surgical planning in two-jaw orthognathic surgery via quantitative comparison of preoperative planned and postoperative actual skull models. Thirty consecutive patients who required two-jaw orthognathic surgery were included. A composite skull model was reconstructed by using Digital Imaging and Communications in Medicine (DICOM) data from spiral computed tomography (CT) and STL (stereolithography) data from surface scanning of the dental arch. LeFort I osteotomy of the maxilla and bilateral sagittal split ramus osteotomy (of the mandible were simulated by using Dolphin Imaging 11.7 Premium (Dolphin Imaging and Management Solutions, Chatsworth, CA). Genioplasty was performed, if indicated. The virtual plan was then transferred to the operation room by using three-dimensional (3-D)-printed surgical templates. Linear and angular differences between virtually simulated and postoperative skull models were evaluated. The virtual surgical planning was successfully transferred to actual surgery with the help of 3-D-printed surgical templates. All patients were satisfied with the postoperative facial profile and occlusion. The overall mean linear difference was 0.81 mm (0.71 mm for the maxilla and 0.91 mm for the mandible); and the overall mean angular difference was 0.95 degrees. Virtual surgical planning and 3-D-printed surgical templates facilitated the diagnosis, treatment planning, and accurate repositioning of bony segments in two-jaw orthognathic surgery. Copyright © 2016 Elsevier Inc. All rights reserved.

Transjugular liver biopsy with use of the shark jaw needle: diagnostic yield, complications, and cost-effectiveness.

PubMed

Psooy, B J; Clark, T W; Beecroft, J R; Malatjalian, D

2001-01-01

Obtaining transjugular liver biopsy specimens with use of single-use needle systems is expensive, whereas biopsy specimens obtained with use of reusable needle systems are frequently associated with inadequate core specimens. The authors report their experience with the reusable Cook Shark Jaw biopsy needle, including diagnostic yield, complications, and cost-effectiveness. A retrospective audit was performed of a cohort of 134 patients who underwent 136 transjugular liver biopsies with use of a reusable 16-gauge Shark Jaw needle during a 30-month period. Specimen adequacy and complication rates were assessed and direct costs of expendable components calculated. Cost-effectiveness was expressed as cost-per-successful biopsy. Biopsies were technically successful in 126 of 136 (93%) patients, with diagnostic histologic core specimens obtained in 124 of 126 (98%) patients, for an overall success rate of 91%. Complications included capsular penetration in six (4.4%) patients, cardiac arrhythmia in two (1.5%) patients, and puncture site hematoma or bleeding in 10 (7.4%) patients. Three tract embolizations were performed for capsular penetration. No instances of subcapsular hematoma, hemoperitoneum, or sepsis occurred, and no deaths were attributed to the procedure. The cost of expendable components totaled $103 per biopsy, corresponding to a cost-effectiveness of $113/successful biopsy. Transjugular liver biopsy specimens obtained with use of the Shark Jaw needle have a diagnostic yield comparable to those obtained with use of single-use biopsy systems, at a substantially lower cost with no increase in serious complications.

Periodontal Tissues, Maxillary Jaw Bone, and Tooth Regeneration Approaches: From Animal Models Analyses to Clinical Applications

PubMed Central

Batool, Fareeha; Strub, Marion; Petit, Catherine; Bugueno, Isaac Maximiliano; Bornert, Fabien; Clauss, François; Kuchler-Bopp, Sabine; Benkirane-Jessel, Nadia

2018-01-01

This review encompasses different pre-clinical bioengineering approaches for periodontal tissues, maxillary jaw bone, and the entire tooth. Moreover, it sheds light on their potential clinical therapeutic applications in the field of regenerative medicine. Herein, the electrospinning method for the synthesis of polycaprolactone (PCL) membranes, that are capable of mimicking the extracellular matrix (ECM), has been described. Furthermore, their functionalization with cyclosporine A (CsA), bone morphogenetic protein-2 (BMP-2), or anti-inflammatory drugs’ nanoreservoirs has been demonstrated to induce a localized and targeted action of these molecules after implantation in the maxillary jaw bone. Firstly, periodontal wound healing has been studied in an induced periodontal lesion in mice using an ibuprofen-functionalized PCL membrane. Thereafter, the kinetics of maxillary bone regeneration in a pre-clinical mouse model of surgical bone lesion treated with BMP-2 or BMP-2/Ibuprofen functionalized PCL membranes have been analyzed by histology, immunology, and micro-computed tomography (micro-CT). Furthermore, the achievement of innervation in bioengineered teeth has also been demonstrated after the co-implantation of cultured dental cell reassociations with a trigeminal ganglia (TG) and the cyclosporine A (CsA)-loaded poly(lactic-co-glycolic acid) (PLGA) scaffold in the jaw bone. The prospective clinical applications of these different tissue engineering approaches could be instrumental in the treatment of various periodontal diseases, congenital dental or cranio-facial bone anomalies, and post-surgical complications. PMID:29772691

Towards an SEMG-based tele-operated robot for masticatory rehabilitation.

PubMed

Kalani, Hadi; Moghimi, Sahar; Akbarzadeh, Alireza

2016-08-01

This paper proposes a real-time trajectory generation for a masticatory rehabilitation robot based on surface electromyography (SEMG) signals. We used two Gough-Stewart robots. The first robot was used as a rehabilitation robot while the second robot was developed to model the human jaw system. The legs of the rehabilitation robot were controlled by the SEMG signals of a tele-operator to reproduce the masticatory motion in the human jaw, supposedly mounted on the moving platform, through predicting the location of a reference point. Actual jaw motions and the SEMG signals from the masticatory muscles were recorded and used as output and input, respectively. Three different methods, namely time-delayed neural networks, time delayed fast orthogonal search, and time-delayed Laguerre expansion technique, were employed and compared to predict the kinematic parameters. The optimal model structures as well as the input delays were obtained for each model and each subject through a genetic algorithm. Equations of motion were obtained by the virtual work method. Fuzzy method was employed to develop a fuzzy impedance controller. Moreover, a jaw model was developed to demonstrate the time-varying behavior of the muscle lengths during the rehabilitation process. The three modeling methods were capable of providing reasonably accurate estimations of the kinematic parameters, although the accuracy and training/validation speed of time-delayed fast orthogonal search were higher than those of the other two aforementioned methods. Also, during a simulation study, the fuzzy impedance scheme proved successful in controlling the moving platform for the accurate navigation of the reference point in the desired trajectory. SEMG has been widely used as a control command for prostheses and exoskeleton robots. However, in the current study by employing the proposed rehabilitation robot the complete continuous profile of the clenching motion was reproduced in the sagittal plane. Copyright �

Bisphosphonate-related osteonecrosis of the jaw: an Italian post-marketing surveillance analysis.

PubMed

Parretta, Elisabetta; Sottosanti, Laura; Sportiello, Liberata; Rafaniello, Concetta; Potenza, Simona; D'Amato, Salvatore; González-González, Rocio; Rossi, Francesco; Colella, Giuseppe; Capuano, Annalisa

2014-09-01

Although bisphosphonate (BP)-related osteonecrosis of the jaw (BRONJ) is well recognized, little is known about it in terms of pathophysiology, epidemiology or management. We analyzed all suspected BRONJ reports sent to the Italian Pharmacovigilance Adverse Event Spontaneous Reporting System (Rete Nazionale Farmacovigilanza [RNF]) to determine their pattern and add new information about this relevant issue. All suspected BRONJ sent to the RNF between 2003 and 2011 were retrieved. After a case-by-case assessment procedure, we analyzed BP type, BP exposure time and time since last use. Between 2003 and 2011, 555 reports of osteonecrosis of the jaw (ONJ) after BP administration were recorded in the RNF. These events occurred mostly in patients affected by cancer (77.84%) in which zoledronate was the most frequently suspected BP. Most patients experienced ONJ after long-term use of the drug (median time of BP exposure being between 1.3 and 8.8 years). Interestingly, 139 (25.05%) cases of ONJ occurred between 2 and 121 months after BP withdrawal. This study shows that BRONJ can occur much earlier than hitherto reported, adds new data on BRONJ onset following ibandronate treatment and reveals that patients who cease BP-based therapy develop ONJ, raising the question of post-treatment monitoring strategies.

Ontogeny of the Alligator Cartilago Transiliens and Its Significance for Sauropsid Jaw Muscle Evolution

PubMed Central

Tsai, Henry P.; Holliday, Casey M.

2011-01-01

The cartilago transiliens is a fibrocartilaginous structure within the jaw muscles of crocodylians. The cartilago transiliens slides between the pterygoid buttress and coronoid region of the lower jaw and connects two muscles historically identified as m. pseudotemporalis superficialis and m. intramandibularis. However, the position of cartilago transiliens, and its anatomical similarities to tendon organs suggest the structure may be a sesamoid linking a single muscle. Incompressible sesamoids often form inside tendons that wrap around bone. However, such structures rarely ossify in reptiles and have thus far received scant attention. We tested the hypothesis that the cartilago transiliens is a sesamoid developed within in one muscle by investigating its structure in an ontogenetic series of Alligator mississippiensis using dissection, 3D imaging, and polarizing and standard light microscopy. In all animals studied, the cartilago transiliens receives collagen fibers and tendon insertions from its two main muscular attachments. However, whereas collagen fibers were continuous within the cartilaginous nodule of younger animals, such continuity decreased in older animals, where the fibrocartilaginous core grew to displace the fibrous region. Whereas several neighboring muscles attached to the fibrous capsule in older individuals, only two muscles had significant contributions to the structure in young animals. Our results indicate that the cartilago transiliens is likely a sesamoid formed within a single muscle (i.e., m. pseudotemporalis superficialis) as it wraps around the pterygoid buttress. This tendon organ is ubiquitous among fossil crocodyliforms indicating it is a relatively ancient, conserved structure associated with the development of the large pterygoid flanges in this clade. Finally, these findings indicate that similar tendon organs exist among potentially homologous muscle groups in birds and turtles, thus impacting inferences of jaw muscle homology

Two cases of multiple ossifying fibromas in the jaws

PubMed Central

2014-01-01

Background The clinicopathologic characteristics of multiple ossifying fibroma (OF) are unclear due to the condition’s rarity, making diagnosis challenging. Sporadic multiple OFs must be distinguished from hyperparathyroidism-jaw tumour syndrome (HPT-JT) related OF and other fibro-osseous lesions. Methods Multiple OF cases were identified from ossifying fibroma cases. Clinical data including age, sex, anatomic site, radiographic features, clinical impression, treatment and available follow-up data as well as serum calcium, phosphorus, and parathyroid hormone (PTH) were recorded. GNAS and HRPT2 genetic mutations were examined in the two present cases. Case reports of sporadic multiple ossifying fibroma and HPT-JT-related OF were also reviewed. Results The two present cases were confirmed as sporadic multiple OF, with no genetic GNAS and HRPT2 mutations found. The incidence of sporadic multiple ossifying fibroma was 2.0% (2/102). The total 18 sporadic multiform OF cases were characterized as followed: 13 (72.2%) female; 5 (27.8%) male; mean age 28.6 years; 2/16 (11.1%) cases only in the mandible; 4/18 (22.2%) cases only in the maxilla; and 12/18 (66.7%) cases in both the maxilla and mandible. Radiographically, the lesions were radiolucent in 5/18 (27.8%) cases and mixed density in 13/18 (72.2%) cases. Along with 24 cases of HPT-JT related OF were reviewed, sixteen (66.7%) patients were diagnosed with a single lesion, and 8 patients (33.3%) were diagnosed with multiple jaw lesions. Conclusions Sporadic multiple OFs are very rare, but must be distinguished from HPT-JT related OF. We strongly recommend that patients diagnosed with multiple ossifying fibromas receive serum PTH testing and mutation screening of HRPT2. Virtual slides http://www.diagnosticpathology.diagnomx.eu/vs/1194507146115753 PMID:24678936

Developmental odontogenic cysts of jaws: a clinical study of 245 cases.

PubMed

Yazdani, Javad; Kahnamouii, Shiva Solahaye

2009-01-01

The aim of this study was to investigate the relative frequency of developmental odontogenic cysts in an Iranian population. In this study 245 cysts from both jaws, treated in the Faculty of Dentistry at Tabriz University of Medical Sciences during a 10-year period from 1998 to 2008, were analyzed in order to evaluate the incidence of such cysts. We had permission from all the patients. Case histories of 65% of male and 35% of female patients were analyzed. The age of the patients varied from 14 to 64 years, with an average of 33.21 ± 10.89. In this 10-year study of odontogenic cysts, 97 cases were developmental odontogenic cysts with the following inci-dence: dentigerous cyst, 44%; odontogenic keratocyst, 36%; primordial cyst, 9%; Gorlin cyst, 2%; lateral periodontal cyst, 3%; eruption cyst, 3%; and gingival cyst, 3% (adults 2%, infants 1%). A total of 60% of the cysts were found in the mandible and 40% in the maxilla. Regarding the mandible, the molar region was involved in 47% of the cases, premolar region in 33% and anterior region in 20% (total = 100%). Regarding the maxilla, the canine-to-canine region was involved in 52% of the cases, premolar region in 20% and molar region in 28% (total = 100%). An important finding in this study was the fact that 39% of the jaw cysts were developmental odontogenic cysts and the most common developmental odontogenic cysts were dentigerous cyst and OKC (odontogenic keratocyst).

Extracting DNA from 'jaws': high yield and quality from archived tiger shark (Galeocerdo cuvier) skeletal material.

PubMed

Nielsen, E E; Morgan, J A T; Maher, S L; Edson, J; Gauthier, M; Pepperell, J; Holmes, B J; Bennett, M B; Ovenden, J R

2017-05-01

Archived specimens are highly valuable sources of DNA for retrospective genetic/genomic analysis. However, often limited effort has been made to evaluate and optimize extraction methods, which may be crucial for downstream applications. Here, we assessed and optimized the usefulness of abundant archived skeletal material from sharks as a source of DNA for temporal genomic studies. Six different methods for DNA extraction, encompassing two different commercial kits and three different protocols, were applied to material, so-called bio-swarf, from contemporary and archived jaws and vertebrae of tiger sharks (Galeocerdo cuvier). Protocols were compared for DNA yield and quality using a qPCR approach. For jaw swarf, all methods provided relatively high DNA yield and quality, while large differences in yield between protocols were observed for vertebrae. Similar results were obtained from samples of white shark (Carcharodon carcharias). Application of the optimized methods to 38 museum and private angler trophy specimens dating back to 1912 yielded sufficient DNA for downstream genomic analysis for 68% of the samples. No clear relationships between age of samples, DNA quality and quantity were observed, likely reflecting different preparation and storage methods for the trophies. Trial sequencing of DNA capture genomic libraries using 20 000 baits revealed that a significant proportion of captured sequences were derived from tiger sharks. This study demonstrates that archived shark jaws and vertebrae are potential high-yield sources of DNA for genomic-scale analysis. It also highlights that even for similar tissue types, a careful evaluation of extraction protocols can vastly improve DNA yield. © 2016 John Wiley & Sons Ltd.

Open-jaw syndrome in chinook salmon (Oncorhynchus tshawytscha) at a hatchery

USGS Publications Warehouse

Crouch, Dennis E.; Yasutake, William T.; Rucker, Robert R.

1973-01-01

Nearly 0.5% of the yearling spring chinook salmon (Oncorhynchus tshawytscha) at a national fish hatchery were observed with mouth agape, the condition occurring in two of 16 ponds. X-radiographs and histological preparations indicated that the articular bone of the lower jaw was malformed and dislocated dorsal and posterior to its normal point of attachment. The bone appeared to be embedded in the mandibular muscle and surrounded by an extensive fibrous tissue network. Genetic aberration, environmental interaction, and teratogenic substances are discussed as possible causes of the anomaly.

Flexible piezoelectric energy harvesting from jaw movements

NASA Astrophysics Data System (ADS)

Delnavaz, Aidin; Voix, Jérémie

2014-10-01

Piezoelectric fiber composites (PFC) represent an interesting subset of smart materials that can function as sensor, actuator and energy converter. Despite their excellent potential for energy harvesting, very few PFC mechanisms have been developed to capture the human body power and convert it into an electric current to power wearable electronic devices. This paper provides a proof of concept for a head-mounted device with a PFC chin strap capable of harvesting energy from jaw movements. An electromechanical model based on the bond graph method is developed to predict the power output of the energy harvesting system. The optimum resistance value of the load and the best stretch ratio in the strap are also determined. A prototype was developed and tested and its performances were compared to the analytical model predictions. The proposed piezoelectric strap mechanism can be added to all types of head-mounted devices to power small-scale electronic devices such as hearing aids, electronic hearing protectors and communication earpieces.

Bruxism defined and graded: an international consensus.

PubMed

Lobbezoo, F; Ahlberg, J; Glaros, A G; Kato, T; Koyano, K; Lavigne, G J; de Leeuw, R; Manfredini, D; Svensson, P; Winocur, E

2013-01-01

To date, there is no consensus about the definition and diagnostic grading of bruxism. A written consensus discussion was held among an international group of bruxism experts as to formulate a definition of bruxism and to suggest a grading system for its operationalisation. The expert group defined bruxism as a repetitive jaw-muscle activity characterised by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible. Bruxism has two distinct circadian manifestations: it can occur during sleep (indicated as sleep bruxism) or during wakefulness (indicated as awake bruxism). For the operationalisation of this definition, the expert group proposes a diagnostic grading system of 'possible', 'probable' and 'definite' sleep or awake bruxism. The proposed definition and grading system are suggested for clinical and research purposes in all relevant dental and medical domains. © 2012 Blackwell Publishing Ltd.

Asymmetric activation of temporalis, masseter, and sternocleidomastoid muscles in temporomandibular disorder patients.

PubMed

Ries, Lilian Gerdi Kittel; Alves, Marcelo Correa; Bérzin, Fausto

2008-01-01

The aim of this study was to analyze the symmetry of the electromyographic (EMG) activity of the temporalis, masseter, and sternocleidomastoid (SCM) muscles in volunteers divided into a control group and a temporomandibular disorder (TMD) group. The surface EMG recordings were made during mandibular rest position, maximal intercuspal position, and during the chewing cycle. Normalized EMG waves of paired muscles were compared by computing a percentage overlapping coefficient (POC). The difference between the groups and between the static and dynamic clenching tests was analyzed through repeated measures, ANOVA. Symmetry of the temporalis, masseter, and SCM muscles activity was smaller in the TMD group compared to the control group. The mandibular postures were also significantly different among themselves. The asymmetric activation of jaw and neck muscles was interpreted as a compensatory strategy to achieve stability for the mandibular and cervical systems during masticatory function.

Oral squamous cell carcinoma arising in a patient after hematopoietic stem cell transplantation with bisphosphonate-related osteonecrosis of the jaws.

PubMed

Arduino, Paolo G; Scully, Crispian; Chiusa, Luigi; Broccoletti, Roberto

2015-01-01

A 55-year-old man with a history of acute myeloid leukaemia treated with hematopoietic stem cell transplantation and with a 5-year history of bisphosphonate-related osteonecrosis of the jaws, following 12 cycles of intravenous zoledronic acid therapy, presented in December 2009 with a history of increasingly severe unilateral lower jaw pain. Oral examination revealed, as previously, exposed bone in the left mandible, but also a new exophytic mass on the lower-left buccal mucosa. Biopsy confirmed a diagnosis of oral squamous cell carcinoma. To the best of our knowledge, this is the first report of an oral squamous cell carcinoma that appeared adjacent to an area of osteochemonecrosis.

The Ups and Downs of ASVAB: Fluctuations in Armed Services Vocational Aptitude Battery Scores and Implications for U.S. Army Force Readiness

DTIC Science & Technology

2017-03-30

reflect my own personal views and are not necessarily endorsed by the National Defense University, Joint Forces Staff College, the Department of State, or...thesis and are sincerely appreciated. I also thank Mr. Jeffrey Turner, JAWS Academic Writing Specialist for his tireless r writing assistance, as well... AR ) 28 Word Knowledge (WK) 29 Mechanical Comprehension (MC) 30 2009-2015 31 General Science (GS) 31 Arithmetic Reasoning ( AR ) 32 Word Knowledge (WK) 32

[Surgical treatment of diseases in the oral cavity and jaws].

PubMed

Nordenram, Ake; Astrand, Per; Nord, Per-Gunnar; Paulin, Gunnar; Feldmann, Hartmut

2005-01-01

Surgical treatment of diseases in the oral cavity and the jaws has been performed since ancient times. However, in the beginning there were mostly simple tooth extractions and treatment of oral infections which could be done. The therapists consisted of a heterogenic group (physicians, barber-surgeons, dental surgeons, smiths, monks etc.). In the beginning of the 20th century great progress was made. Dental surgeons were employed as consultants in hospitals. And when the national dental servIce in Sweden (Folktandvården) was established 1938, departments of oral surgery were built in these hospitals. The department of oral surgery at the University hospital in Linköping started 1947 and is presented in this paper. Dr. Helge Hed, originator of the department, was chief oral surgeon the first 24 years. The surgical activity was gradually increased from 389 operations in 1950 to 1.514 in 1999, and the number of jaw fractures treated in 1948 were 21 and in 1999 73. The treatment panorama has changed during the years. At first the poor dental status of the patients characterized the situation and minor dentoalveolar surgery was usually performed. Later more advanced oral surgery e. g. trauma-surgery, orthognatic surgery and dental implantology has been done - and in addition a lot of scientific research and programmed instructions in oral surgery for dental surgeons and medical students. To sum up, the development of the department of oral surgery at the University hospital in Linköping has been well adjusted to the gradually more demanding treatment and it is representative of the successful development of Swedish oral surgery during the 20th century.

Involvement of histaminergic inputs in the jaw-closing reflex arc

PubMed Central

Gemba, Chikako; Nakayama, Kiyomi; Nakamura, Shiro; Mochizuki, Ayako; Inoue, Tomio

2015-01-01

Histamine receptors are densely expressed in the mesencephalic trigeminal nucleus (MesV) and trigeminal motor nucleus. However, little is known about the functional roles of neuronal histamine in controlling oral-motor activity. Thus, using the whole-cell recording technique in brainstem slice preparations from Wistar rats aged between postnatal days 7 and 13, we investigated the effects of histamine on the MesV neurons innervating the masseter muscle spindles and masseter motoneurons (MMNs) that form a reflex arc for the jaw-closing reflex. Bath application of histamine (100 μM) induced membrane depolarization in both MesV neurons and MMNs in the presence of tetrodotoxin, whereas histamine decreased and increased the input resistance in MesV neurons and MMNs, respectively. The effects of histamine on MesV neurons and MMNs were mimicked by an H1 receptor agonist, 2-pyridylethylamine (100 μM). The effects of an H2 receptor agonist, dimaprit (100 μM), on MesV neurons were inconsistent, whereas MMNs were depolarized without changes in the input resistance. An H3 receptor agonist, immethridine (100 μM), also depolarized both MesV neurons and MMNs without changing the input resistance. Histamine reduced the peak amplitude of postsynaptic currents (PSCs) in MMNs evoked by stimulation of the trigeminal motor nerve (5N), which was mimicked by 2-pyridylethylamine but not by dimaprit or immethridine. Moreover, 2-pyridylethylamine increased the failure rate of PSCs evoked by minimal stimulation and the paired-pulse ratio. These results suggest that histaminergic inputs to MesV neurons through H1 receptors are involved in the suppression of the jaw-closing reflex although histamine depolarizes MesV neurons and/or MMNs. PMID:25904711

Clinical performance of a lithia disilicate-based core ceramic for three-unit posterior FPDs.

PubMed

Esquivel-Upshaw, Josephine F; Anusavice, Kenneth J; Young, Henry; Jones, Jack; Gibbs, Charles

2004-01-01

The purpose of this research project was to determine the clinical success rate of a lithia disilicate-based core ceramic for use in posterior fixed partial dentures (FPD) as a function of bite force, cement type, connector height, and connector width. Thirty ceramic FPD core frameworks were prepared using a heat-pressing technique and a lithia disilicate-based core ceramic. The maximum clenching force was measured for each patient prior to tooth preparation. Connector height and width were measured for each FPD. Patients were recalled yearly after cementation for 2 years and evaluated using 11 clinical criteria. All FPDs were examined by two independent clinicians, and rankings from 1 to 4 were made for each criterion (4 = excellent; 1 = unacceptable). Two of the 30 ceramic FPDs fractured within the 2-year evaluation period, representing a 93% success rate. One fracture was associated with a low occlusal force and short connector height (2.9 mm). The other fracture was associated with the greatest occlusal force (1,031 N) and adequate connector height. All criteria were ranked good to excellent during the 2-year recall for all remaining FPDs. The performance of the experimental core ceramic in posterior FPDs was promising, with only a 7% fracture rate after 2 years. Because of the limited sample size, it is not possible to identify the maximum clenching force that is allowable to prevent fracture caused by interocclusal forces.

Homology of the jaw muscles in lizards and snakes-a solution from a comparative gnathostome approach.

PubMed

Johnston, Peter

2014-03-01

Homology or shared evolutionary origin of jaw adductor muscles in lizards and snakes has been difficult to establish, although snakes clearly arose within the lizard radiation. Lizards typically have temporal adductors layered lateral to medial, and in snakes the muscles are arranged in a rostral to caudal pattern. Recent work has suggested that the jaw adductor group in gnathostomes is arranged as a folded sheet; when this theory is applied to snakes, homology with lizard morphology can be seen. This conclusion revisits the work of S.B. McDowell, J Herpetol 1986; 20:353-407, who proposed that homology involves identity of m. levator anguli oris and the loss of m. adductor mandibulae externus profundus, at least in "advanced" (colubroid) snakes. Here I advance the folded sheet hypothesis across the whole snake tree using new and literature data, and provide a solution to this homology problem. Copyright © 2014 Wiley Periodicals, Inc.

Multiple jaw cysts-unveiling the Gorlin-Goltz syndrome.

PubMed

Manjima, S; Naik, Zameera; Keluskar, Vaishali; Bagewadi, Anjana

2015-03-01

Gorlin-Goltz syndrome or basal cell nevus syndrome is a comparatively rare syndrome characterized by basal cell nevi, odontogenic keratocysts, and skeletal anomalies. Diagnosis is based on the major and minor clinical and radiographic criteria. Dentist plays a major role in the diagnosis of this disease due to the oral and maxillofacial manifestations of the syndrome. In some cases, jaw cysts are diagnosed by routine radiographs advised by the dentists. Odontogenic keratocysts in such syndromic patients will be multiple and extensive and in some cases results in cortical expansion and facial disfigurement. Thorough clinical examination and investigations prompt an early confirmation of the syndrome, which is very essential to avoid morbidity associated with the syndrome. Here, we report a case of multiple odontogenic cysts in a 16-year-old patient which later was diagnosed as a case of Gorlin Goltz syndrome.

Multiple jaw cysts-unveiling the Gorlin-Goltz syndrome

PubMed Central

Manjima, S.; Naik, Zameera; Keluskar, Vaishali; Bagewadi, Anjana

2015-01-01

Gorlin-Goltz syndrome or basal cell nevus syndrome is a comparatively rare syndrome characterized by basal cell nevi, odontogenic keratocysts, and skeletal anomalies. Diagnosis is based on the major and minor clinical and radiographic criteria. Dentist plays a major role in the diagnosis of this disease due to the oral and maxillofacial manifestations of the syndrome. In some cases, jaw cysts are diagnosed by routine radiographs advised by the dentists. Odontogenic keratocysts in such syndromic patients will be multiple and extensive and in some cases results in cortical expansion and facial disfigurement. Thorough clinical examination and investigations prompt an early confirmation of the syndrome, which is very essential to avoid morbidity associated with the syndrome. Here, we report a case of multiple odontogenic cysts in a 16-year-old patient which later was diagnosed as a case of Gorlin Goltz syndrome. PMID:25821359

Evaluation of the dose calculation accuracy for small fields defined by jaw or MLC for AAA and Acuros XB algorithms.

PubMed

Fogliata, Antonella; Lobefalo, Francesca; Reggiori, Giacomo; Stravato, Antonella; Tomatis, Stefano; Scorsetti, Marta; Cozzi, Luca

2016-10-01

Small field measurements are challenging, due to the physical characteristics coming from the lack of charged particle equilibrium, the partial occlusion of the finite radiation source, and to the detector response. These characteristics can be modeled in the dose calculations in the treatment planning systems. Aim of the present work is to evaluate the MU calculation accuracy for small fields, defined by jaw or MLC, for anisotropic analytical algorithm (AAA) and Acuros XB algorithms, relative to output measurements on the beam central axis. Single point output factor measurement was acquired with a PTW microDiamond detector for 6 MV, 6 and 10 MV unflattened beams generated by a Varian TrueBeam STx equipped with high definition-MLC. Fields defined by jaw or MLC apertures were set; jaw-defined: 0.6 × 0.6, 0.8 × 0.8, 1 × 1, 2 × 2, 3 × 3, 4 × 4, 5 × 5, and 10 × 10 cm 2 ; MLC-defined: 0.5 × 0.5 cm 2 to the maximum field defined by the jaw, with 0.5 cm stepping, and jaws set to: 2 × 2, 3 × 3, 4 × 4, 5 × 5, and 10 × 10 cm 2 . MU calculation was obtained with 1 mm grid in a virtual water phantom for the same fields, for AAA and Acuros algorithms implemented in the Varian eclipse treatment planning system (version 13.6). Configuration parameters as the effective spot size (ESS) and the dosimetric leaf gap (DLG) were varied to find the best parameter setting. Differences between calculated and measured doses were analyzed. Agreement better than 0.5% was found for field sizes equal to or larger than 2 × 2 cm 2 for both algorithms. A dose overestimation was present for smaller jaw-defined fields, with the best agreement, averaged over all the energies, of 1.6% and 4.6% for a 1 × 1 cm 2 field calculated by AAA and Acuros, respectively, for a configuration with ESS = 1 mm for both X and Y directions for AAA, and ESS = 1.5 and 0 mm for X and Y directions for Acuros. Conversely, a calculated dose underestimation was found for small MLC-defined fields, with the

Hyperarticulation in Lombard speech: Global coordination of the jaw, lips and the tongue.

PubMed

Šimko, Juraj; Beňuš, Štefan; Vainio, Martti

2016-01-01

Over the last century, researchers have collected a considerable amount of data reflecting the properties of Lombard speech, i.e., speech in a noisy environment. The documented phenomena predominately report effects on the speech signal produced in ambient noise. In comparison, relatively little is known about the underlying articulatory patterns of Lombard speech, in particular for lingual articulation. Here the authors present an analysis of articulatory recordings of speech material in babble noise of different intensity levels and in hypoarticulated speech and report quantitative differences in relative expansion of movement of different articulatory subsystems (the jaw, the lips and the tongue) as well as in relative expansion of utterance duration. The trajectory modifications for one articulator can be relatively reliably predicted by those for another one, but subsystems differ in a degree of continuity in trajectory expansion elicited across different noise levels. Regression analysis of articulatory modifications against durational expansion shows further qualitative differences between the subsystems, namely, the jaw and the tongue. The findings are discussed in terms of possible influences of a combination of prosodic, segmental, and physiological factors. In addition, the Lombard effect is put forward as a viable methodology for eliciting global articulatory variation in a controlled manner.

Plate-like permanent dental laminae of upper jaw dentition in adult gobiid fish, Sicyopterus japonicus.

PubMed

Moriyama, Keita; Watanabe, Shun; Iida, Midori; Sahara, Noriyuki

2010-04-01

Sicyopterus japonicus (Teleostei, Gobiidae) possesses a unique upper jaw dentition different from that known for any other teleosts. In the adults, many (up to 30) replacement teeth, from initiation to attachment, are arranged orderly in a semicircular-like strand within a capsule of connective tissue on the labial side of each premaxillary bone. We have applied histological, ultrastructural, and three-dimensional imaging from serial sections to obtain insights into the distribution and morphological features of the dental lamina in the upper jaw dentition of adult S. japonicus. The adult fish has numerous permanent dental laminae, each of which is an infolding of the oral epithelium at the labial side of the functional tooth and forms a thin plate-like structure with a wavy contour. All replacement teeth of a semicircular-like strand are connected to the plate-like dental lamina by the outer dental epithelium and form a tooth family; neighboring tooth families are completely separated from each other. The new tooth germ directly buds off from the ventro-labial margin of the dental lamina, whereas no distinct free end of the dental lamina is present, even adjacent to this region. Cell proliferation concentrated at the ventro-labial margin of the dental lamina suggests that this region is the site for repeated tooth initiation. During tooth development, the replacement tooth migrates along a semicircular-like strand and eventually erupts through the dental lamina into the oral epithelium at the labial side of the functional tooth. This unique thin plate-like permanent dental lamina and the semicircular-like strand of replacement teeth in the upper jaw dentition of adult S. japonicus probably evolved as a dental adaptation related to the rapid replacement of teeth dictated by the specialized feeding habit of this algae-scraping fish.

Long-term results after treatment of extensive odontogenic cysts of the jaws: a review.

PubMed

Wakolbinger, Robert; Beck-Mannagetta, Johann

2016-01-01

The aim was to perform a literature review concerning long-term results after treatment of extensive cysts of the jaws. The following databases were searched: MEDLINE, Cochrane CENTRAL, Cochrane Database of Systematic Reviews, The Cochrane Library, and EMBASE. Case reports and abstracts were excluded. Three hundred fifty-six articles were found, of which 30 were included. Only the minority of the studies reported long-term results. Most authors did not distinguish between temporary complications and permanent deficiencies (incomplete bone healing, permanent sensory deficits). Based on this review, it is recommended to consider primary decompression or marsupialization ± later definitive surgery for the treatment of extensive jaw cysts in order to achieve satisfying clinical results. Complications (occurring within the first 6 months postoperatively, e.g., infection) and remaining deficits (after a minimum of 6 months and not changing over time, e.g., bony or sensory deficit) should be clearly separated from each other. Knowledge of permanent deficits and bone healing after different therapeutic approaches is important for decision making. Patients should be informed not only about complications but also about the risk of permanent deficits for each method.

Two-argument total scatter factor for small fields simultaneously collimated by MLC and jaws: application to stereotactic radiosurgery and radiotherapy

NASA Astrophysics Data System (ADS)

Han, Zhaohui; Friesen, Scott; Hacker, Fred; Zygmanski, Piotr

2018-01-01

Direct use of the total scatter factor (S tot) for independent monitor unit (MU) calculations can be a good alternative approach to the traditional separate treatment of head/collimator scatter (S c) and phantom scatter (S p), especially for stereotactic small fields under the simultaneous collimation of secondary jaws and tertiary multileaf collimators (MLC). We have carried out the measurement of S tot in water for field sizes down to 0.5  ×  0.5 cm2 on a Varian TrueBeam STx medical linear accelerator (linac) equipped with high definition MLCs. Both the jaw field size (c) and MLC field size (s) significantly impact the linac output factors, especially when c \\gg s and s is small (e.g. s  <  5 cm). The combined influence of MLC and jaws gives rise to a two-argument dependence of the total scatter factor, S tot(c,s), which is difficult to functionally decouple. The (c,s) dependence can be conceived as a set of s-dependent functions (‘branches’) defined on domain [s min, s max  =  c] for a given jaw size of c. We have also developed a heuristic model of S tot to assist the clinical implementation of the measured S tot data for small field dosimetry. The model has two components: (i) empirical fit formula for the s-dependent branches and (ii) interpolation scheme between the branches. The interpolation scheme preserves the characteristic shape of the measured branches and effectively transforms the measured trapezoidal domain in (c,s) plane to a rectangular domain to facilitate easier two-dimensional interpolation to determine S tot for arbitrary (c,s) combinations. Both the empirical fit and interpolation showed good agreement with experimental validation data.

Dosimetric investigation of dual energy photon beams with assymmetric collimator jaws

NASA Astrophysics Data System (ADS)

Varatharaj, C.; Ravikumar, M.; Supe, Sanjay S.; Sathiyan, S.; Ganesh, K. M.; Arunkumar, T.

2008-01-01

Many modern linear accelerators are equipped with asymmetric collimators or jaws that can be moved independently. Asymmetric jaws have got many clinical applications in radiation therapy. In the present study, the dosimetric characteristics of asymmetric collimators from our linear accelerator with 6 and 18 MV X-rays were carried out. The field size factors (FSF) and half value layer (HVL) were measured in a water phantom using 0.6 cc Farmer chamber for symmetric and asymmetric fields for both 6 and 18 MV X-rays. Measurements of beam penumbra, percentage depth dose (PDD), cross beam profiles and calculated isodose curves were measured by RFA 300 for both asymmetric and symmetric fields. The FSF were found to agree with in 3% for symmetric and asymmetric fields. The HVL in water was found to be 15.8 cm and 14.4 cm for 6 MV photons and 26 cm and 22.9 cm for 18 MV photons at the central axis and at 20 cm off the central axis. At 30 cm depth the percentage depth dose for symmetric and asymmetric fields were found to differ as high as 6% for 6 MV and 4% for 18 MV fields. No observable difference in penumbra was noticed for symmetric and asymmetric fields of same dimensions. The constrictions of isodose curves at the edge nearer to central axis were noticed for asymmetrically placed fields. The observed differences could be due to the passage of primary beam through differential thickness of the flattening filter which alters the beam quality.

Developmental Odontogenic Cysts of Jaws: A Clinical Study of 245 Cases

PubMed Central

Yazdani, Javad; Kahnamouii, Shiva Solahaye

2009-01-01

Background and aims The aim of this study was to investigate the relative frequency of developmental odontogenic cysts in an Iranian population. Materials and methods In this study 245 cysts from both jaws, treated in the Faculty of Dentistry at Tabriz University of Medical Sciences during a 10-year period from 1998 to 2008, were analyzed in order to evaluate the incidence of such cysts. We had permission from all the patients. Case histories of 65% of male and 35% of female patients were analyzed. The age of the patients varied from 14 to 64 years, with an average of 33.21 ± 10.89. Results In this 10-year study of odontogenic cysts, 97 cases were developmental odontogenic cysts with the following inci-dence: dentigerous cyst, 44%; odontogenic keratocyst, 36%; primordial cyst, 9%; Gorlin cyst, 2%; lateral periodontal cyst, 3%; eruption cyst, 3%; and gingival cyst, 3% (adults 2%, infants 1%). A total of 60% of the cysts were found in the mandible and 40% in the maxilla. Regarding the mandible, the molar region was involved in 47% of the cases, premolar region in 33% and anterior region in 20% (total = 100%). Regarding the maxilla, the canine-to-canine region was involved in 52% of the cases, premolar region in 20% and molar region in 28% (total = 100%). Conclusion An important finding in this study was the fact that 39% of the jaw cysts were developmental odontogenic cysts and the most common developmental odontogenic cysts were dentigerous cyst and OKC (odontogenic keratocyst). PMID:23230485

A high-resolution line sensor-based photostereometric system for measuring jaw movements in 6 degrees of freedom.

PubMed

Hayashi, T; Kurokawa, M; Miyakawa, M; Aizawa, T; Kanaki, A; Saitoh, A; Ishioka, K

1994-01-01

Photostereometry has widely been applied to the measurement of mandibular movements in 6 degrees of freedom. In order to improve the accuracy of this measurement, we developed a system utilizing small LEDs mounted on the jaws in redundant numbers and a 5000 pixel linear charge-coupled device (CCD) as a photo-sensor. A total of eight LEDs are mounted on the jaws, in two sets of four, by means of connecting facebows, each weighing approximately 55 g. The position of the LEDs are detected in three-dimensions by two sets of three CCD cameras, located bilaterally. The position and orientation of the mandible are estimated from the positions of all LEDs measured in the sense of least-squares, thereby effectively reducing the measurement errors. The static overall accuracy at all tooth and condylar points was considered to lie within 0.19 and 0.34 mm, respectively, from various accuracy verification tests.

Oral Squamous Cell Carcinoma Arising in a Patient after Hematopoietic Stem Cell Transplantation with Bisphosphonate-Related Osteonecrosis of the Jaws

PubMed Central

Scully, Crispian; Chiusa, Luigi; Broccoletti, Roberto

2015-01-01

A 55-year-old man with a history of acute myeloid leukaemia treated with hematopoietic stem cell transplantation and with a 5-year history of bisphosphonate-related osteonecrosis of the jaws, following 12 cycles of intravenous zoledronic acid therapy, presented in December 2009 with a history of increasingly severe unilateral lower jaw pain. Oral examination revealed, as previously, exposed bone in the left mandible, but also a new exophytic mass on the lower-left buccal mucosa. Biopsy confirmed a diagnosis of oral squamous cell carcinoma. To the best of our knowledge, this is the first report of an oral squamous cell carcinoma that appeared adjacent to an area of osteochemonecrosis. PMID:25973278

A Comparative Evaluation of Condylar Guidance Value from Radiograph with Interocclusal Records made During Jaw Relation and Try-in: A Pilot Study.

PubMed

Shetty, Shilpa; Satish Babu, C L; Tambake, Deepti; Surendra Kumar, G P; Setpal, Abhishek T

2013-09-01

The purpose of this study was to evaluate the reliability of programming the articulator using the radiographs and the interocclusal records made during Jaw relation (Arrow point tracing) and Try-in stage. The study comprised of 15 edentulous subjects with well formed maxillary and mandibular ridges, with no signs and symptoms of temporomandibular joint disorders and neuromuscular disorders. Digital Orthopantomograph was taken for all the subjects. The condylar guidance angles were traced on Orthopantomograph for right and left sides and the values were recorded. The protrusive interocclusal records were made at jaw relation stage and at try-in stage using bite registration paste (Bitrex- vinyl polysiloxane) for all subjects. These interocclusal records were used to programme the Semi-adjustable articulator (Hanau Wide Vue) and the condylar guidance values on the right and left sides were recorded. The condylar guidance values so obtained were compared with the values obtained by Orthopantomograph. The condylar guidance values obtained by the various procedures were subjected to statistical analysis. The results showed statistically significant difference between the condylar guidance values obtained from Orthopantomograph (Radiograph) and the condylar guidance values obtained at the stage of jaw relation and also between Orthopantomograph and condylar guidance values obtained at the stage of Try-in. Condylar guidance values obtained from the Radiographs were higher than those obtained at the stage of Jaw relation and at the stage of Try-in. However, we notice that the mean condylar guidance values obtained at the stage of Try-in were nearer to the mean condylar guidance values obtained on the Radiographs.

Follicular cyst of the jaw developing into a keratocyst in a patient with unrecognized Gorlin-Goltz syndrome.

PubMed

Longobardi, Gianluigi; Diana, Giovanni; Poddi, Valentina; Pagano, Immacolata

2010-05-01

Gorlin-Goltz (GG) syndrome is an inherited autosomal dominant condition. Its diagnosis may be clinically confirmed by checking either major or minor signs that define the diagnostic criteria. It may occur that, although GG syndrome is a well-known condition, only the specific symptom could be observed by different specialists. Therefore, the patient cannot be placed into an always complex clinical panel. We introduce an example in this report. Throughout a 20-year clinical history characterized by the lack of proper diagnosis and missed follow-up operations, a patient with GG syndrome underwent partial amputation of the jaw after severe complications. A 52-year-old man required an implant-prosthetic rehabilitation since becoming edentulous after a partial resection of the jaw due to a keratocyst, which was later reconstructed through a free fibula flap. The observation of a typical phenotype and various symptoms that succeeded for longer than 20 years, with anamnestic evaluation and clinical examination, led us to suspect a complex pathologic condition such as GG syndrome, which was not previously considered, although the patient had undergone several polyspecialistic evaluations. Diagnosis has been eventually confirmed by a genetic study, which was always mandatory. The simultaneous presence of muscular and skeletal malformations, basocellular nevi, and multiple cysts of the jaw can represent signs linking to a condition such as GG syndrome. There are many syndromes involving the head and neck region, and specialists are supposed to be alerted when faced with similar typical expressions associated with a characteristic soma so as to avoid delays in diagnosing the syndrome.

Age-related declines in the swallowing muscle strength of men and women aged 20-89 years: A cross-sectional study on tongue pressure and jaw-opening force in 980 subjects.

PubMed

Hara, Koji; Tohara, Haruka; Kobayashi, Kenichiro; Yamaguchi, Kohei; Yoshimi, Kanako; Nakane, Ayako; Minakuchi, Shunsuke

2018-05-31

Swallowing muscle strength weakens with aging. Although numerous studies have investigated tongue pressure (TP) changes with age, studies on jaw-opening force (JOF), an indicator of suprahyoid muscle strength, are lacking. We investigated differences between age-related declines in TP and JOF in a cross-sectional study of 980 healthy and independent participants (379 men, 601 women) without dysphagia. Hand grip strength (HGS), TP, and JOF were compared among decade-based age groups in multiple comparison analyses with post-hoc tests and effect size calculated. Participants were divided into adult (20 s-50 s) and elderly groups (60 s-80 s); within each group, Pearson correlations between age and muscle strength indices were evaluated. TP started to significantly decline in the 60 s and 50 s for men and women (p < .01, medium effect size and p < .05, small effect size, respectively); HGS also declined at these ages (men: p < .01, women: p < .01, medium effect size). JOF started to significantly decline in men in their 80 s (p < .01, large effect size), but remained unchanged in women. In the elderly group, all measurements declined with age more sharply in men (HGS: r = -0.56, TP: r = -0.63, JOF: r = -0.13) than in women (HGS: r = -0.38, TP: r = -0.49, JOF: r = -0.003). TP declined more steeply than did JOF. Thus, the age related-decline in TP was similar to that of the HGS, but not the JOF. The results reveal that different patterns exist in the age-related decline in swallowing muscle strength, and suggest that maintenance of JOF might contribute to safe swallowing in healthy elderly individuals. Copyright © 2018 Elsevier B.V. All rights reserved.

Thermomechanical assessment of the effects of a jaw-beam angle during beam impact on Large Hadron Collider collimators

NASA Astrophysics Data System (ADS)

Cauchi, Marija; Assmann, R. W.; Bertarelli, A.; Carra, F.; Lari, L.; Rossi, A.; Mollicone, P.; Sammut, N.

2015-02-01

The correct functioning of a collimation system is crucial to safely and successfully operate high-energy particle accelerators, such as the Large Hadron Collider (LHC). However, the requirements to handle high-intensity beams can be demanding, and accident scenarios must be well studied in order to assess if the collimator design is robust against possible error scenarios. One of the catastrophic, though not very probable, accident scenarios identified within the LHC is an asynchronous beam dump. In this case, one (or more) of the 15 precharged kicker circuits fires out of time with the abort gap, spraying beam pulses onto LHC machine elements before the machine protection system can fire the remaining kicker circuits and bring the beam to the dump. If a proton bunch directly hits a collimator during such an event, severe beam-induced damage such as magnet quenches and other equipment damage might result, with consequent downtime for the machine. This study investigates a number of newly defined jaw error cases, which include angular misalignment errors of the collimator jaw. A numerical finite element method approach is presented in order to precisely evaluate the thermomechanical response of tertiary collimators to beam impact. We identify the most critical and interesting cases, and show that a tilt of the jaw can actually mitigate the effect of an asynchronous dump on the collimators. Relevant collimator damage limits are taken into account, with the aim to identify optimal operational conditions for the LHC.

Sympathomimetic effects of chronic methamphetamine abuse on oral health: a cross-sectional study.

PubMed

Rommel, Niklas; Rohleder, Nils H; Koerdt, Steffen; Wagenpfeil, Stefan; Härtel-Petri, Roland; Wolff, Klaus-Dietrich; Kesting, Marco R

2016-05-26

Methamphetamine, a highly addictive sympathomimetic stimulant, is currently widely abused worldwide and has been associated with devastating effects on oral health, resulting in the term "meth mouth". However, "meth mouth" pathology is primarily based on case reports with a lack of systematic clinical evaluation. Therefore, we have conducted a systematic study to investigate (1) the pharmacological impact of methamphetamine on oral health with regard to saliva function, including the parameters saliva flow rate and total saliva production (ml/5 min) and the buffering capacity of saliva; (2) the contribution of the symptoms of bruxism and muscle trismus to potential oral health damage. We assessed the data of 100 chronic methamphetamine abusers and 100 matched-pair comparison participants. Primarily, we conducted an anamnesis with all methamphetamine abusers with regard to saliva dysfunctions, jaw clenching and pain in the temporomandibular joint. Subsequently, in the first part of the clinical enquiry, we tested the saliva flow rate and the total saliva production (ml/5 min) by using the sialometry method and the buffer capacity of saliva by determining the pH-value. In the second part of the clinical enquiry, we evaluated bruxism symptoms with respect to generalized tooth attrition, dentine exposure and visible enamel cracks and examined a potential muscle trismus by measuring the maximal opening of the mouth. The majority of methamphetamine abusers reported a dry mouth (72 %) and jaw clenching (68 %). Almost half of all methamphetamine abusers experienced pain in the temporomandibular joint (47 %). With regard to the clinical findings, methamphetamine abusers showed significantly lower total saliva production (ml/5 min) (p < 0.001), lower pH-values of their saliva (p < 0.001) and more bruxism symptoms (p < 0.001). However, we found no relevant trismus symptoms on comparing the two groups (p > 0.05). The sympathomimetic effects of chronic

Medication-related osteonecrosis of the jaw. Introduction of a new modified experimental model.

PubMed

Curra, Cláudia; Cardoso, Camila Lopes; Ferreira, Osny; Curi, Marcos Martins; Matsumoto, Mariza Akemi; Cavenago, Bruno Cavalini; Santos, Pâmela Letícia Dos; Santiago, Joel Ferreira

2016-05-01

To evaluate a modified experimental model for medication-related osteonecrosis of the jaw (MRONJ) through the upper right central incisor extraction followed by intravenous bisphosphonate administration. Forty five rats underwent the upper right central incisor tooth extraction were divided in 2 groups: Group I - experimental group, 30 rats received an intravenous administration protocol of zoledronic acid 35μg/kg into the tail vein every two weeks, totalizing four administrations, during eight weeks of administration, previously the extraction, and Group II - control group, 15 rats didn't received any medication before extraction. The groups were subdivided in postoperative periods: 14/28/42 days. Clinical analysis and microtomography were performed to verify the presence of osteonecrosis. In addition, descritive histological analysis of hematoxylin-eosin stained sections was performed to evaluate the presence of osteonecrosis or necrotic foci. Twelve (40%) rats, from experimental group, showed clinical signs of MRONJ (p=0.005), however, all samples showed imaginologic findings like osteolysis and loss of integrity of the cellular walls (p≤0.001). Microscopic evaluation revealed osteonecrosis areas with microbial colonies and inflammatory infiltrate (p≤0.001). In the control group, all animals presented the chronology of a normal wound healing. The presence of medication-related osteonecrosis of the jaw after maxillary central incisor extraction in rats. This new experimental model may be considered an option for the study of MRONJ.

Non-Radiation-Related Osteonecrosis of the Jaws in Dogs: 14 Cases (1996–2014)

PubMed Central

Peralta, Santiago; Arzi, Boaz; Nemec, Ana; Lommer, Milinda J.; Verstraete, Frank J. M.

2015-01-01

Osteonecrosis of the jaws (ONJ) is an entity of major clinical impact characterized by chronically exposed necrotic mandibular or maxillary bone. Its clinicopathological characteristics and possible inciting or risk factors are well described in humans but only anecdotally reported in dogs. Treatment modalities and outcome vary depending on the inciting factors involved and the extent and severity of the lesions. The objectives of this study were to retrospectively describe the clinicopathological features of non-radiation-related ONJ in a series of 14 dogs, identify possible inciting or risk factors, and report on the surgical treatment and outcome. For all patients, the medical records were used to collect information regarding signalment, clinical signs, characteristics of the oral, jaw and dental lesions, diagnostic imaging findings, histopathological and microbiological analysis, treatment performed, and outcome. The data collected showed that non-radiation-related ONJ appears to be an infrequent clinical entity but of significant impact in dogs; that a history of systemic antibiotics and dental disease is common among affected dogs; that previous dental extractions are commonly associated with ONJ sites; that using a systematic diagnostic approach is essential for diagnosis; and that thorough surgical debridement combined with a course of oral antibiotics was effective in the described dogs affected by advanced non-radiation-related ONJ. PMID:26664936

Bony outgrowths on the jaws of an extinct sperm whale support macroraptorial feeding in several stem physeteroids

NASA Astrophysics Data System (ADS)

Lambert, Olivier; Bianucci, Giovanni; Beatty, Brian L.

2014-06-01

Several extinct sperm whales (stem Physeteroidea) were recently proposed to differ markedly in their feeding ecology from the suction-feeding modern sperm whales Kogia and Physeter. Based on cranial, mandibular, and dental morphology, these Miocene forms were tentatively identified as macroraptorial feeders, able to consume proportionally large prey using their massive teeth and robust jaws. However, until now, no corroborating evidence for the use of teeth during predation was available. We report on a new specimen of the stem physeteroid Acrophyseter, from the late middle to early late Miocene of Peru, displaying unusual bony outgrowths along some of the upper alveoli. Considering their position and outer shape, these are identified as buccal maxillary exostoses. More developed along posterior teeth and in tight contact with the high portion of the dental root outside the bony alveoli, the exostoses are hypothesized to have developed during powerful bites; they may have worked as buttresses, strengthening the teeth when facing intense occlusal forces. These buccal exostoses further support a raptorial feeding technique for Acrophyseter and, indirectly, for other extinct sperm whales with a similar oral apparatus ( Brygmophyseter, Livyatan, Zygophyseter). With a wide size range, these Miocene stem physeteroids were major marine macropredators, occupying ecological niches nowadays mostly taken by killer whales.

Time and order of eruption of first functional teeth in the upper jaw of post-larval life of Sicyopterus japonicus (Gobiidiae: Sicydiinae) during cranial metamorphosis at the time of river recruitment.

PubMed

Sahara, Noriyuki; Moriyama, Keita; Iida, Midori; Watanabe, Shun

2016-06-01

The present study was aimed at elucidating the time and order of eruption of first functional teeth in the upper jaw of post-larval life of Sicyopterus japonicus (S. japonicus) during cranial metamorphosis at the time of river recruitment. Fishes were caught at the post-larval stage at a river mouth and maintained for 7 days in a water tank. Each of 10 specimens was evaluated every day for 7 days by using microcomputed tomography, scanning electron microscopy, and light microscopy with peculiar attention to the development of the upper jaw teeth. Fishes caught at the river mouth were mostly transparent, with a rostral terminal mouth, and no teeth could be found in either the upper or lower jaw. At 2 days after collection, the mouth position changed from terminal to subterminal, resulting from a change in head shape. The initial eruption of first functional teeth was detected at the anterior two-thirds region of each upper jaw. These teeth erupted in adjacent positions, most had a tricuspid crown, and they represented miniature versions of adult teeth. At 5 days, the position of the mouth became further relocated from terminal rostral to ventral. The number of erupted teeth increased, followed by spreading of them anteriorly and posteriorly. At 7 days, they formed a single row of close-set tricuspid teeth along the entire length of each upper jaw. The present study demonstrated that even under laboratory conditions a rapid and drastic cranial metamorphosis took place within a week after the time of collection of post-larval S. japonicus from a river. The eruption of first functional teeth in the upper jaw of S. japonicus, which teeth are adapted to scraping algae off the substrate, was initially detected at 2 days after collection, and first functional dentition of the upper jaw was set up within 7 days after it. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sleep bruxism: Current knowledge and contemporary management

PubMed Central

Yap, Adrian U.; Chua, Ai Ping

2016-01-01

Bruxism is defined as the repetitive jaw muscle activity characterized by the clenching or grinding of teeth. It can be categorized into awake and sleep bruxism (SB). Frequent SB occurs in about 13% of adults. The exact etiology of SB is still unknown and probably multifactorial in nature. Current literature suggests that SB is regulated centrally (pathophysiological and psychosocial factors) and not peripherally (morphological factors). Cited consequences of SB include temporomandibular disorders, headaches, tooth wear/fracture, implant, and other restoration failure. Chairside recognition of SB involves the use of subjective reports, clinical examinations, and trial oral splints. Definitive diagnosis of SB can only be achieved using electrophysiological tools. Pharmacological, psychological, and dental strategies had been employed to manage SB. There is at present, no effective treatment that “cures” or “stops” SB permanently. Management is usually directed toward tooth/restoration protection, reduction of bruxism activity, and pain relief. PMID:27656052

Sleep Bruxism in Respiratory Medicine Practice.

PubMed

Mayer, Pierre; Heinzer, Raphael; Lavigne, Gilles

2016-01-01

Sleep bruxism (SB) consists of involuntary episodic and repetitive jaw muscle activity characterized by occasional tooth grinding or jaw clenching during sleep. Prevalence decreases from 20% to 14% in childhood to 8% to 3% in adulthood. Although the causes and mechanisms of idiopathic primary SB are unknown, putative candidates include psychologic risk factors (eg, anxiety, stress due to life events, hypervigilance) and sleep physiologic reactivity (eg, sleep arousals with autonomic activity, breathing events). Although certain neurotransmitters (serotonin, dopamine, noradrenalin, histamine) have been proposed to play an indirect role in SB, their exact contribution to rhythmic masticatory muscle activity (RMMA) (the electromyography marker of SB) genesis remains undetermined. No specific gene is associated with SB; familial environmental influence plays a significant role. To date, no single explanation can account for the SB mechanism. Secondary SB with sleep comorbidities that should be clinically assessed are insomnia, periodic limb movements during sleep, sleep-disordered breathing (eg, apnea-hypopnea), gastroesophageal reflux disease, and neurologic disorders (eg, sleep epilepsy, rapid eye movement behavior disorder). SB is currently quantified by scoring RMMA recordings in parallel with brain, respiratory, and heart activity recordings in a sleep laboratory or home setting. RMMA confirmation with audio-video recordings is recommended for better diagnostic accuracy in the presence of neurologic conditions. Management strategies (diagnostic tests, treatment) should be tailored to the patient's phenotype and comorbidities. In the presence of sleep-disordered breathing, a mandibular advancement appliance or CPAP treatment is preferred over single occlusal splint therapy on the upper jaw. Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

Symptoms of craniomandibular dysfunction in professional orchestra musicians.

PubMed

Steinmetz, A; Zeh, A; Delank, K S; Peroz, I

2014-01-01

Up to 80% of professional musicians are affected by playing-related musculoskeletal disorders, but data regarding the frequency of craniomandibular dysfunction (CMD) in professional orchestra musicians is scarce. To evaluate the frequency of CMD and its relation to musculoskeletal pain in various body regions. A questionnaire-based survey approach assessing CMD symptoms and musculoskeletal pain in professional orchestra players was adopted. Relative prevalence rates and prevalence ratios for different instrument groups were estimated. A total of 408 musicians completed the questionnaire (response rate 57%). Playing-related pain in the teeth or jaw was reported by 19-47% of musicians and TMJ pain by 15-34%, depending on the instrument group. Current pain in the face indicating a painful CMD was reported in 6-10% and related symptoms such as teeth grinding in 25-34%, jaw clenching in 33-42% and jaw locking in 11-18% of musicians. Females were 2.4 times (95% confidence intervals (CI) 1.49-3.84) more likely to report having had orofacial pain within the last month. Musicians reporting orofacial pain within the last month were 4.8 times (95% CI: 2.83-8.02) more likely to report pain in the neck and 2.5-3.8 times (P < 0.05) more likely to report pain in other body regions, including shoulders, right wrist, left fingers and the thoracic and lumbar spine. Symptoms suggesting CMD were common in this study of professional orchestra musicians and were associated with pain in the neck, shoulder and hands. There is a need to enhance awareness of CMD to optimize early medical diagnosis and treatment.

Intraosseous Leiomyoma of the Jaw in an Adolescent.

PubMed

Valls-Ontañón, Adaia; Pozuelo-Arquimbau, Laura; Mateu-Esquerda, Gemma; Arranz-Obispo, Carlos; Cuscó-Albors, Sílvia; Melero-Luque, Mireia; Morla, Arnaud; Marí-Roig, Antoni

2017-05-15

Leiomyoma is a benign tumor of the smooth muscle that rarely occurs in the mouth as an intraosseous lesion. The purposes of this paper are to: (1) present a case of an intraosseous solid leiomyoma of the mandible in a 13-year-old child, who presented with a well-defined unilocular radiolucency in the right mandible incidentally discovered during a routine dental radiographic examination; and (2) conduct a review of the literature to describe clinicopathological features and management of intraosseous jaw leiomyoma (IJL). A total of 17 articles describing 18 cases of IJL satisfied the selection criteria; including the present patient, to date a total of 19 cases of IJL have been reported. IJL occurs mainly in young patients (36.8 percent), more often in boys (1:5:1 male-to-female ratio), and reaches a larger size in children than in adults. The treatment of choice for IJL is surgical excision, which should be as minimally invasive as possible, especially in children.

Concurrent simulation of a parallel jaw end effector

NASA Technical Reports Server (NTRS)

Bynum, Bill

1985-01-01

A system of programs developed to aid in the design and development of the command/response protocol between a parallel jaw end effector and the strategic planner program controlling it are presented. The system executes concurrently with the LISP controlling program to generate a graphical image of the end effector that moves in approximately real time in response to commands sent from the controlling program. Concurrent execution of the simulation program is useful for revealing flaws in the communication command structure arising from the asynchronous nature of the message traffic between the end effector and the strategic planner. Software simulation helps to minimize the number of hardware changes necessary to the microprocessor driving the end effector because of changes in the communication protocol. The simulation of other actuator devices can be easily incorporated into the system of programs by using the underlying support that was developed for the concurrent execution of the simulation process and the communication between it and the controlling program.

PubMed Central

Nozaki, S.; Kawai, M.; Shimoyama, R.; Futamura, N.; Matsumura, T.; Adachi, K.; Kikuchi, Y.

2010-01-01

The purpose of this study is to evaluate whether the range of motion exercise of the temporo-mandibular joint (jaw ROM exercise) with a hot pack and massage of the masseter muscle improve biting disorder in Duchenne muscular dystrophy (DMD). The subjects were 18 DMD patients (21.3 ± 4.1 years old). The jaw ROM exercise consisted of therapist-assisted training (2 times a week) and self-training (before each meal every day). The therapist-assisted training consisted of the application of a hot pack on the cheek of the masseter muscle region (15 minutes), the massage of the masseter (10 minutes), and jaw ROM exercise (5 minutes). The self-training involved jaw ROM exercise by opening the mouth to the maximum degree, ten times. These trainings continued for six months. Outcomes were evaluated by measuring the greatest occlusal force and the distance at the maximum degree of mouth opening between an incisor of the top and that of the bottom. Six months later, the greatest occlusal force had increased significantly compared with that at the start of jaw ROM exercise (intermediate values: from 73.8N to 97.3N) (p = 0.005) as determined by the Friedman test and Scheffé's nonparametric test. The patients' satisfaction with meals increased. However, the maximum degree of mouth opening did not change after six months of jaw ROM exercise. Jaw ROM exercise in DMD is effective for increasing the greatest occlusal force. PMID:21574523

Allometric shape change of the lower pharyngeal jaw correlates with a dietary shift to piscivory in a cichlid fish.

PubMed

Hellig, Christoph J; Kerschbaumer, Michaela; Sefc, Kristina M; Koblmüller, Stephan

2010-07-01

The morphological versatility of the pharyngeal jaw of cichlid fishes is assumed to represent a key factor facilitating their unparalleled trophic diversification and explosive radiation. It is generally believed that the functional design of an organism relates to its ecology, and thus, specializations to different diets are typically associated with distinct morphological designs, especially manifested in the cichlids' pharyngeal jaw apparatus. Thereby, the lower pharyngeal jaw (LPJ) incorporates some of the most predictive features for distinct diet-related morphotypes. Thus, considering that piscivorous cichlids experience an ontogenetic dietary shift from typically various kinds of invertebrates to fish, concomitant morphological changes in the LPJ are expected. Using Lepidiolamprologus elongatus, a top predator in the shallow rocky habitat of Lake Tanganyika, as model, and applying geometric and traditional morphometric techniques, we demonstrate an allometric change in ontogenetic LPJ shape development coinciding with the completion of the dietary shift toward piscivory. The piscivorous LPJ morphotype is initiated in juvenile fish by increasing elongation and narrowing of the LPJ and--when the fish reach a size of 80-90 mm standard length--further refined by the elongation of the posterior muscular processes, which serve as insertion for the fourth musculus levator externus. The enlarged muscular processes of the fully mature piscivorous morphotype provide for the construction of a powerful lever system, which allows the large individuals to process large prey fish and rely on exclusive piscivory.

Allometric shape change of the lower pharyngeal jaw correlates with a dietary shift to piscivory in a cichlid fish

NASA Astrophysics Data System (ADS)

Hellig, Christoph J.; Kerschbaumer, Michaela; Sefc, Kristina M.; Koblmüller, Stephan

2010-07-01

The morphological versatility of the pharyngeal jaw of cichlid fishes is assumed to represent a key factor facilitating their unparalleled trophic diversification and explosive radiation. It is generally believed that the functional design of an organism relates to its ecology, and thus, specializations to different diets are typically associated with distinct morphological designs, especially manifested in the cichlids’ pharyngeal jaw apparatus. Thereby, the lower pharyngeal jaw (LPJ) incorporates some of the most predictive features for distinct diet-related morphotypes. Thus, considering that piscivorous cichlids experience an ontogenetic dietary shift from typically various kinds of invertebrates to fish, concomitant morphological changes in the LPJ are expected. Using Lepidiolamprologus elongatus, a top predator in the shallow rocky habitat of Lake Tanganyika, as model, and applying geometric and traditional morphometric techniques, we demonstrate an allometric change in ontogenetic LPJ shape development coinciding with the completion of the dietary shift toward piscivory. The piscivorous LPJ morphotype is initiated in juvenile fish by increasing elongation and narrowing of the LPJ and—when the fish reach a size of 80-90 mm standard length—further refined by the elongation of the posterior muscular processes, which serve as insertion for the fourth musculus levator externus. The enlarged muscular processes of the fully mature piscivorous morphotype provide for the construction of a powerful lever system, which allows the large individuals to process large prey fish and rely on exclusive piscivory.

Whole Genome Duplications Shaped the Receptor Tyrosine Kinase Repertoire of Jawed Vertebrates

PubMed Central

Brunet, Frédéric G.; Volff, Jean-Nicolas; Schartl, Manfred

2016-01-01

The receptor tyrosine kinase (RTK) gene family, involved primarily in cell growth and differentiation, comprises proteins with a common enzymatic tyrosine kinase intracellular domain adjacent to a transmembrane region. The amino-terminal portion of RTKs is extracellular and made of different domains, the combination of which characterizes each of the 20 RTK subfamilies among mammals. We analyzed a total of 7,376 RTK sequences among 143 vertebrate species to provide here the first comprehensive census of the jawed vertebrate repertoire. We ascertained the 58 genes previously described in the human and mouse genomes and established their phylogenetic relationships. We also identified five additional RTKs amounting to a total of 63 genes in jawed vertebrates. We found that the vertebrate RTK gene family has been shaped by the two successive rounds of whole genome duplications (WGD) called 1R and 2R (1R/2R) that occurred at the base of the vertebrates. In addition, the Vegfr and Ephrin receptor subfamilies were expanded by single gene duplications. In teleost fish, 23 additional RTK genes have been retained after another expansion through the fish-specific third round (3R) of WGD. Several lineage-specific gene losses were observed. For instance, birds have lost three RTKs, and different genes are missing in several fish sublineages. The RTK gene family presents an unusual high gene retention rate from the vertebrate WGDs (58.75% after 1R/2R, 64.4% after 3R), resulting in an expansion that might be correlated with the evolution of complexity of vertebrate cellular communication and intracellular signaling. PMID:27260203

Sleep bruxism possibly triggered by multiple sclerosis attacks and treated successfully with botulinum toxin: Report of three cases.

PubMed

Sevim, Serhan; Kaleağası, Hakan; Fidancı, Halit

2015-09-01

Sleep bruxism refers to a nocturnal parafunctional activity including the clenching, grinding or gnashing of teeth. While most of the nocturnal bruxism cases seen in the general population are apparently idiopathic, it has been reported to be associated with a range of neurological diseases such as Huntington's disease, cranio-cervical dystonia and post-anoxic brain damage, but not multiple sclerosis (MS). We describe three cases of MS patients who have had moderate to severe complaints of bruxism in the two weeks following their relevant MS attacks. None of the three patients had a diagnosis of bruxism prior to her attack. The diagnosis was confirmed in one out of three by a polysomnography. One patient did not have any complaints related to bruxism previous to her attack, whereas two had mild and infrequent complaints. The symptoms of the relevant attacks were left hemihypesthesia in all and hemiparesis in two. None of the patients had spasticity that could result in severe teeth clenching. All three patients presented with morning headaches and jaw pain or tightness and were treated successfully with botulinum toxin (Btx) injections applied to their masseter and temporalis muscles. The cause of bruxism is controversial but lesions of the cortico-basalganglia-thalamo-cotrical loops are thought to be most likely. However, acute or chronic lesions in those pathways were not demonstrated in the 3 patients. It is feasible that they had normal appearing white matter interruptions in their cortico-basalganglia-thalamocortical loops along with their relevant attack. Copyright © 2015 Elsevier B.V. All rights reserved.

Tapia's Syndrome after Corrective Jaw Surgery under General Anesthesia: A Case Report.

PubMed

Izadi, Farzad; Ahmadi, Aslan; Daneshvar, Ali; Safdarian, Mahdi

2017-03-01

Tapia's syndrome is a rare complication of recurrent laryngeal and hypoglossal nerve paralysis due to anesthetic airway mismanagement or malpositioning of the patient's head during surgery. Here we present a case of Tapia's syndrome in a 22-year-old male after corrective jaw surgery under general anesthesia, with a long period of recovery, related to airway management procedures and/or overstretching of the neck during positioning for surgery. Although it is a rare condition, every surgeon should be aware of Tapia's syndrome in order to consider the correct positioning of the head and endotracheal tube during surgery and avoid this complication.

Proteomics and immunohistochemistry identify the expression of α-cardiac myosin heavy chain in the jaw-closing muscles of sooty mangabeys (order Primates).

PubMed

Wall, Christine E; Holmes, Megan; Soderblom, Erik J; Taylor, Andrea B

2018-07-01

The jaw-closing muscles of humans and nonprimate mammals express alpha-cardiac fibers but MyHC α-cardiac has not been identified in the jaw adductors of nonhuman primates. We determined whether MyHC α-cardiac is expressed in the superficial masseter and temporalis muscles of the sooty mangabey (Cercocebus atys), an African Old World monkey that specializes on hard seeds. LC-MS/MS based proteomics was used to identify the presence of MyHC Iα. Immunohistochemistry was used to analyze the composition and distribution of fiber types in the superficial masseter and temporalis muscles of eight C. atys. Serial sections were stained against MyHC α-cardiac (MYH6), as well as MyHC-1 (NOQ7.5.4D), MyHC-2 (MY-32), and MyHC-M (2F4). Proteomics analysis identified the presence of Myosin-6 (MyHC α-cardiac) in both heart atrium and superficial masseter. MyHC α-cardiac was expressed in abundance in the superficial masseter and temporalis muscles of all eight individuals and hybrid fibers were common. The identification of MyHC α-cardiac in the jaw adductors of sooty mangabeys is a novel finding for nonhuman primates. The abundance of MyHC α-cardiac indicates a fatigue-resistant fiber population characterized by intermediate speed of contraction between pure MyHC-1 and MyHC-2 isoforms. We suggest that α-cardiac fibers may be advantageous to sooty mangabeys, whose feeding behavior includes frequent crushing of relatively large, hard seeds during the power stroke of ingestion. Additional studies comparing jaw-adductor fiber phenotype of hard-object feeding primates and other mammals are needed to explore this relationship further. Copyright © 2018 Elsevier Ltd. All rights reserved.

Medication-related osteonecrosis of the jaws from once per year intravenous zoledronic acid (Reclast): report of 4 cases.

PubMed

Lee, Cameron Y S; Suzuki, Jon B

2015-04-01

Osteonecrosis of the jaws is a commonly reported side effect with patients prescribed oral antiresorptive medications to treat osteoporosis and osteopenia. Oral antiresorptive agents are considered as the standard of care for the prevention and treatment of women with postmenopausal osteoporosis. Because of patient's noncompliance of the antiresorptive medications, which may require once-weekly or once-monthly oral ingestion, a new once a year intravenous (IV) infusion of zoledronic acid was recently introduced in the management of osteoporosis. Reports of medication-related osteonecrosis of the jaw (MRONJ) have been reported in patients with cancer treated with multiple doses of IV zoledronic acid. However, there is a paucity of reports occurring with the once-yearly infusion of zoledronic acid (Reclast) for the management of osteoporosis. In this article, we report 4 cases of patients who had a history of long-term oral antiresorptive therapy and now were taking the once-yearly IV zoledronic acid (Reclast) and soon developed MRONJ after completing surgery of the maxilla and mandible.

Influence of the teaching program on the learning in knowledge and practice of osteonecrosis of the jaws produced by antireasorptives in dental students of the Principality of Asturias (Spain)

PubMed Central

Escobedo, Matias-Ferrán; García-Consuegra, Luis; Gay, Silvia; Álvarez, Lorena; Olay, Sonsoles; Ascani, Giuliano

2017-01-01

Background This study aims to evaluate the influence of changes in the teaching contents on medication-related osteonecrosis of the jaw may have on the knowledge and the capacity for practical case resolution about this pathology. Material and Methods A cross-sectional descriptive study was conducted through a survey divided into four sections: degree of means of knowledge acquisition, habitual practice and ability to solve clinical cases. The total number of respondents (n = 225) was divided into two groups: Group A (Year 2015-2016) and Group B (Year 2016-2017). The students in Group B received more teaching content on the subject than group A. Results A total of 175 survey responses were collected. The internet was the preferred tool for continuing education in both groups. The best known bisphosphonates (BPs) were Alendronate (Fosamax®: 56.9% Group A, 67.5% Group B) and Zoledronic Acid (Zometa®: 56.9% Group A, 51.8% Group B). A low percentage of students (37.9% Group A, 43.4% Group B) acknowledged the existence of other drugs that could also cause osteonecrosis of the jaws. Regarding the correct resolution of practical cases, the respondents of Group B reached a significantly higher score (5.67) than the score observed in Group A (4.04). Conclusions Training on medication-related osteonecrosis among dental students is susceptible to improvement. Introducing minor changes in the teachings allows this goal to be successfully achieved. Key words:Osteonecrosis of the jaw (ONJ), bisphosphonate-related osteonecrosis of the jaws (BRONJ), medication-related osteonecrosis of the jaw (MRONJ), dental education. PMID:29410755

Optimizing Hybrid Occlusion in Face-Jaw-Teeth Transplantation: A Preliminary Assessment of Real-Time Cephalometry as Part of the Computer-Assisted Planning and Execution Workstation for Craniomaxillofacial Surgery.

PubMed

Murphy, Ryan J; Basafa, Ehsan; Hashemi, Sepehr; Grant, Gerald T; Liacouras, Peter; Susarla, Srinivas M; Otake, Yoshito; Santiago, Gabriel; Armand, Mehran; Gordon, Chad R

2015-08-01

The aesthetic and functional outcomes surrounding Le Fort-based, face-jaw-teeth transplantation have been suboptimal, often leading to posttransplant class II/III skeletal profiles, palatal defects, and "hybrid malocclusion." Therefore, a novel technology-real-time cephalometry-was developed to provide the surgical team instantaneous, intraoperative knowledge of three-dimensional dentoskeletal parameters. Mock face-jaw-teeth transplantation operations were performed on plastic and cadaveric human donor/recipient pairs (n = 2). Preoperatively, cephalometric landmarks were identified on donor/recipient skeletons using segmented computed tomographic scans. The computer-assisted planning and execution workstation tracked the position of the donor face-jaw-teeth segment in real time during the placement/inset onto recipient, reporting pertinent hybrid cephalometric parameters from any movement of donor tissue. The intraoperative data measured through real-time cephalometry were compared to posttransplant measurements for accuracy assessment. In addition, posttransplant cephalometric relationships were compared to planned outcomes to determine face-jaw-teeth transplantation success. Compared with postoperative data, the real-time cephalometry-calculated intraoperative measurement errors were 1.37 ± 1.11 mm and 0.45 ± 0.28 degrees for the plastic skull and 2.99 ± 2.24 mm and 2.63 ± 1.33 degrees for the human cadaver experiments. These results were comparable to the posttransplant relations to planned outcome (human cadaver experiment, 1.39 ± 1.81 mm and 2.18 ± 1.88 degrees; plastic skull experiment, 1.06 ± 0.63 mm and 0.53 ± 0.39 degrees). Based on this preliminary testing, real-time cephalometry may be a valuable adjunct for adjusting and measuring "hybrid occlusion" in face-jaw-teeth transplantation and other orthognathic surgical procedures.

Intravenous bisphosphonate-related osteonecrosis of the jaws: Influence of coadjuvant antineoplastic treatment and study of buccodental condition

PubMed Central

Bagán, José; Poveda-Roda, Rafael

2013-01-01

Objectives: To determine whether coadjuvant antineoplastic treatment can influence the number and size of bone exposures among patients with intravenous bisphosphonate-related osteonecrosis of the jaws (iBRONJ), and to analyze the buccodental condition of these patients. Material and methods: The study sample comprised 67 patients with iBRONJ, 53 patients without iBRONJ receiving treatment with intravenous bisphosphonates, and 36 healthy subjects. In all three groups, measurements were made of the CAO index and of resting whole saliva and stimulated whole saliva. In the patients with iBRONJ, the size (cm) and number of bone exposures were recorded. The data obtained were subjected to analysis of variance (ANOVA), the Mann-Whitney U-test, and multivariate logistic regression analysis. Results: A total of 57.6% of the patients presented single bone exposure, 25.4% presented two, and 17% more than two exposures. The mean exposure size was 2.3±1.9 cm. Neither the bivariate analysis nor the multivariate multiple regression analysis found coadjuvant antineoplastic treatment to exert a statistically significant effect upon the number and size of bone exposures. On the other hand, there were statistically significant differences among the three study groups in relation to the CAO index (p=0.02) and the number of missing teeth (p=0.00). The resting whole saliva and stimulated whole saliva levels were similar in the three groups, though the patients with osteonecrosis of the jaws showed comparatively lower SWS levels. Conclusions: Coadjuvant antineoplastic treatment alone appears to exert no influence upon the size and number of bone exposures in iBRONJ. The patients with this disease show a higher CAO index and a larger number of missing teeth. Key words:Osteonecrosis of the jaws, bisphosphonates, bone exposure, CAO index, resting whole saliva, stimulated whole saliva. PMID:23229272

Selecting Question-Specific Genes to Reduce Incongruence in Phylogenomics: A Case Study of Jawed Vertebrate Backbone Phylogeny.

PubMed

Chen, Meng-Yun; Liang, Dan; Zhang, Peng

2015-11-01

Incongruence between different phylogenomic analyses is the main challenge faced by phylogeneticists in the genomic era. To reduce incongruence, phylogenomic studies normally adopt some data filtering approaches, such as reducing missing data or using slowly evolving genes, to improve the signal quality of data. Here, we assembled a phylogenomic data set of 58 jawed vertebrate taxa and 4682 genes to investigate the backbone phylogeny of jawed vertebrates under both concatenation and coalescent-based frameworks. To evaluate the efficiency of extracting phylogenetic signals among different data filtering methods, we chose six highly intractable internodes within the backbone phylogeny of jawed vertebrates as our test questions. We found that our phylogenomic data set exhibits substantial conflicting signal among genes for these questions. Our analyses showed that non-specific data sets that are generated without bias toward specific questions are not sufficient to produce consistent results when there are several difficult nodes within a phylogeny. Moreover, phylogenetic accuracy based on non-specific data is considerably influenced by the size of data and the choice of tree inference methods. To address such incongruences, we selected genes that resolve a given internode but not the entire phylogeny. Notably, not only can this strategy yield correct relationships for the question, but it also reduces inconsistency associated with data sizes and inference methods. Our study highlights the importance of gene selection in phylogenomic analyses, suggesting that simply using a large amount of data cannot guarantee correct results. Constructing question-specific data sets may be more powerful for resolving problematic nodes. © The Author(s) 2015. Published by Oxford University Press, on behalf of the Society of Systematic Biologists. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Marcus Gunn jaw-winking synkinesis: clinical features and management.

PubMed

Demirci, Hakan; Frueh, Bartley R; Nelson, Christine C

2010-07-01

To evaluate the clinical features including eyelid excursion and management of Marcus Gunn jaw-winking synkinesis (MGJWS). Observational case series. Forty-eight consecutive patients with MGJWS. Clinical features and management of 48 patients with MGJWS were reviewed retrospectively. Upper eyelid excursion was measured and graded. Complications of surgical intervention were evaluated. Resolution of MGJWS and symmetry of upper eyelids in primary position. Excursion of the ptotic eyelid with jaw movement in MGJWS was graded as mild (<2 mm) in 16% of patients, moderate (2-4 mm) in 76% of patients, and severe (> or = 5 mm) in 8% of patients. Thirty patients with moderate or severe MGJWS underwent disabling of the involved levator muscle and bilateral or unilateral frontalis suspension and had more than 6 months of follow-up. After a mean follow-up of 62 months, MGJWS resolved in 29 (97%) patients and improved from 6 mm to 2 mm in 1 (3%) patient. Relative upper eyelid height was within 1 mm in 87% of patients in primary position and within 1 mm in 80% of patients in downgaze. Twenty-six patients had bilateral frontalis suspension with disabling of unilateral levator muscle on the involved side. Relative upper eyelid height was within 1 mm in 88% of patients in the primary position and within 1 mm in 88% of patients in downgaze. Four non-amblyopic patients had unilateral frontalis suspension with levator muscle disabling. Relative upper eyelid height was symmetrical in 75% of the patients in primary position and in 25% of patients in downgaze. Complications included eyelash ptosis in 10% of the patients, loss of eyelid crease in 10%, and entropion in 3%. Most of the patients with MGJWS exhibited moderate eyelid excursion. Disabling of the involved levator muscle and bilateral frontalis suspension and, in selected cases, disabling of the involved levator muscle and unilateral frontalis suspension were effective in the treatment of MGJWS. Eyelash ptosis and loss of eyelid

Effect of peripherally and cortically evoked swallows on jaw reflex responses in anesthetized rabbits.

PubMed

Suzuki, Taku; Yoshihara, Midori; Sakai, Shogo; Tsuji, Kojun; Nagoya, Kouta; Magara, Jin; Tsujimura, Takanori; Inoue, Makoto

2018-05-03

This study aimed to investigate whether the jaw-opening (JOR) and jaw-closing reflexes (JCR) are modulated during not only peripherally, but also centrally, evoked swallowing. Experiments were carried out on 24 adult male Japanese white rabbits. JORs were evoked by trigeminal stimulation at 1 Hz for 30 sec. In the middle 10 sec, either the superior laryngeal nerve (SLN) or cortical swallowing area (Cx) was simultaneously stimulated to evoke swallowing. The peak-to-peak JOR amplitude was reduced during the middle and late 10-sec periods (i.e., during and after SLN or Cx stimulation), and the reduction was dependent on the current intensity of SLN/Cx stimulation: greater SLN/Cx stimulus current resulted in greater JOR inhibition. The reduction rate was significantly greater during Cx stimulation than during SLN stimulation. The amplitude returned to baseline 2 min after 10-sec SLN/Cx stimulation. The effect of co-stimulation of SLN and Cx was significantly greater than that of SLN stimulation alone. There were no significant differences in any parameters of the JCR between conditions. These results clearly showed that JOR responses were significantly suppressed, not only during peripherally evoked swallowing but also during centrally evoked swallowing, and that the inhibitory effect is likely to be larger during centrally compared with peripherally evoked swallowing. The functional implications of these results are discussed. Copyright © 2018. Published by Elsevier B.V.

Pleiotropic functions of embryonic sonic hedgehog expression link jaw and taste bud amplification with eye loss during cavefish evolution.

PubMed

Yamamoto, Yoshiyuki; Byerly, Mardi S; Jackman, William R; Jeffery, William R

2009-06-01

This study addresses the role of sonic hedgehog (shh) in increasing oral-pharyngeal constructive traits (jaws and taste buds) at the expense of eyes in the blind cavefish Astyanax mexicanus. In cavefish embryos, eye primordia degenerate under the influence of hyperactive Shh signaling. In concert, cavefish show amplified jaw size and taste bud numbers as part of a change in feeding behavior. To determine whether pleiotropic effects of hyperactive Shh signaling link these regressive and constructive traits, shh expression was compared during late development of the surface-dwelling (surface fish) and cave-dwelling (cavefish) forms of Astyanax. After an initial expansion along the midline of early embryos, shh was elevated in the oral-pharyngeal region in cavefish and later was confined to taste buds. The results of shh inhibition and overexpression experiments indicate that Shh signaling has an important role in oral and taste bud development. Conditional overexpression of an injected shh transgene at specific times in development showed that taste bud amplification and eye degeneration are sensitive to shh overexpression during the same early developmental period, although taste buds are not formed until much later. Genetic crosses between cavefish and surface fish revealed an inverse relationship between eye size and jaw size/taste bud number, supporting a link between oral-pharyngeal constructive traits and eye degeneration. The results suggest that hyperactive Shh signaling increases oral and taste bud amplification in cavefish at the expense of eyes. Therefore, selection for constructive oral-pharyngeal traits may be responsible for eye loss during cavefish evolution via pleiotropic function of the Shh signaling pathway.

Stiffening the stingray skeleton - an investigation of durophagy in myliobatid stingrays (Chondrichthyes, batoidea, myliobatidae).

PubMed

Summers, A P

2000-02-01

The stingray family Myliobatidae contains five durophagous (hard prey specialist) genera and two planktivorous genera. A suite of morphological features makes it possible for the hard prey specialists to crush mollusks and crustaceans in their cartilaginous jaws. These include: 1) flat, pavement-like tooth plates set in an elastic dental ligament; 2) multiple layers of calcified cartilage on the surface of the jaws; 3) calcified struts running through the jaws; and 4) a lever system that amplifies the force of the jaw adductors. Examination of a range of taxa reveals that the presence of multiple layers of calcified cartilage, previously described from just a few species, is a plesiomorphy of Chondrichthyes. Calcified struts within the jaw, called "trabecular cartilage," are found only in the myliobatid genera, including the planktivorous Manta birostris. In the durophagous taxa, the struts are concentrated under the area where prey is crushed, thereby preventing local buckling of the jaws. Trabecular cartilage develops early in ontogeny, and does not appear to develop as a direct result of the stresses associated with feeding on hard prey. A "nutcracker" model of jaw function is proposed. In this model, the restricted gape, fused mandibular and palatoquadrate symphyses, and asynchronous contraction of the jaw adductors function to amplify the closing force by 2-4 times. Copyright 2000 Wiley-Liss, Inc.

Whole Genome Duplications Shaped the Receptor Tyrosine Kinase Repertoire of Jawed Vertebrates.

PubMed

Brunet, Frédéric G; Volff, Jean-Nicolas; Schartl, Manfred

2016-06-03

The receptor tyrosine kinase (RTK) gene family, involved primarily in cell growth and differentiation, comprises proteins with a common enzymatic tyrosine kinase intracellular domain adjacent to a transmembrane region. The amino-terminal portion of RTKs is extracellular and made of different domains, the combination of which characterizes each of the 20 RTK subfamilies among mammals. We analyzed a total of 7,376 RTK sequences among 143 vertebrate species to provide here the first comprehensive census of the jawed vertebrate repertoire. We ascertained the 58 genes previously described in the human and mouse genomes and established their phylogenetic relationships. We also identified five additional RTKs amounting to a total of 63 genes in jawed vertebrates. We found that the vertebrate RTK gene family has been shaped by the two successive rounds of whole genome duplications (WGD) called 1R and 2R (1R/2R) that occurred at the base of the vertebrates. In addition, the Vegfr and Ephrin receptor subfamilies were expanded by single gene duplications. In teleost fish, 23 additional RTK genes have been retained after another expansion through the fish-specific third round (3R) of WGD. Several lineage-specific gene losses were observed. For instance, birds have lost three RTKs, and different genes are missing in several fish sublineages. The RTK gene family presents an unusual high gene retention rate from the vertebrate WGDs (58.75% after 1R/2R, 64.4% after 3R), resulting in an expansion that might be correlated with the evolution of complexity of vertebrate cellular communication and intracellular signaling. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Analysis of different therapeutic protocols for osteonecrosis of the jaw associated with oral and intravenous bisphpsphonates

PubMed Central

Bermúdez-Bejarano, Elena-Beatriz; Serrera-Figallo, María-Ángeles; Gutiérrez-Corrales, Aida; Romero-Ruiz, Manuel-María; Castillo-de-Oyagüe, Raquel; Gutiérrez-Pérez, José-Luis; Machuca-Portillo, Guillermo

2017-01-01

Introduction Chemotherapy-associated osteonecrosis of the jaw caused by bisphosphonates is an exposure of necrotic bone with more than eight weeks of evolution that is attributable to bisphosphonates and no prior radiation therapy. Its etiopathogenesis remains unknown, although there are two hypotheses that may explain it: the drug’s mechanism of action, and the risk factors that can lead to osteonecrosis. There is a wide range of treatment options for managing chemotherapy-associated osteonecrosis of the jaw, from conservative treatments to surgical procedures of varying levels of invasiveness, which are sometimes supplemented with adjuvant therapies. Objectives The objective of this article is to group the therapeutic options for osteonecrosis of the jaw (ONJ) into seven different protocols and to evaluate their effectiveness in relation to stage of ONJ. Material and Methods A literature review was carried out in PubMed following the PRISMA criteria. A total of 47 were collected after compiling a series of variables that define ONJ, applied treatments, and the clinical results obtained. Results and Discussion The 47 articles selected have a low to average estimated risk of bias and are of moderate to good quality. According to the data obtained, Protocol 3 (conservative treatment, clinical and radiological follow-up, minimally invasive surgical treatment, and adjuvant therapies) is the most favorable approach for ONJ lesions caused by oral bisphosphonates. For lesions caused by intravenous bisphosphonates, Protocol 2 (conservative treatment, clinical and radiological follow-up, minimally invasive surgical treatment, and no adjuvant therapies) is the best approach. When comparing the different stages of ONJ, Protocol 1 (conservative treatment, clinical and radiological follow-up) promotes better healing of Stage 1 ONJ lesions caused by orally administered bisphosphonates, and Protocol 3 is recommended for Stage II. For ONJ lesions attributable to intravenous

DEPENDENCE OF MORPHOMETRIC PARAMETERS OF THE DENTAL OCCLUSION ON THE TYPE OF THE LOWER JAW GROWTH IN CHILDREN WITH CLASS II1 DENTOFACIAL ANOMALIES WHO LINE IN THE NORTHERN UKRAINE.

PubMed

Galich, L V; Kuroedova, V; Lakhtin, Yu; Galich, L B; Moskalenko, P

2017-03-01

The aim of the work was to study the structure of dentofacial anomalies in children and adolescents in Sumy city and Sumy oblast, to identify dentoalveolar morphological peculiarities of the occlusion in 10-13 years old patients with class ІІ1 anomalies according to Angle's classification with different types of lower jaw bone growth. A retrospective analysis of 2236 outpatient dental cards of urban and rural patients with orthodontic pathology was conducted. Patients were divided into three age groups: 6-9 years old (early mixed occlusion) - 592 children; 10-13 years old (late mixed occlusion) - 1180 children; over 13 years old (permanent occlusion) - 464 persons; besides 76 patients with class ІІ1 anomalies according to Angle's classification aged 10-13 years were examined. To determine the type of lower jaw growth, the children underwent orthopantomographic examination, diagnostic models were made and biometric indicators were calculated to determine the severity of the morphological changes. It was established that anomalies of individual teeth and dental curve dominated in all age groups (71.24%). Among the occlusion anomalies, a large part falls to class ІІ anomalies according to Angle's classification (19.18%). A third of these patients have a neutral type of lower jaw growth (36.84±5.53%), horizontal and vertical types of growth reach 18.42±4.47% and 19.74±4.56%, respectively. The combination of neutral and vertical type of growth of the lower jaw occurs in 1.7 times more than the combination of neutral and horizontal. The most pronounced morphological changes were observed in the group of patients with a horizontal type of lower jaw growth. When planning treatment and prophylactic measures among patients of the orthodontic profile, it is necessary to take into account the peculiarities of both the prevalence of pathology in the region and the morphological changes of different severity in the dental curves of the jaws.

Optimizing Hybrid Occlusion in Face-Jaw-Teeth Transplantation: A Preliminary Assessment of Real-Time Cephalometry as Part of the Computer-Assisted Planning and Execution Workstation for Craniomaxillofacial Surgery

PubMed Central

Murphy, Ryan J.; Basafa, Ehsan; Hashemi, Sepehr; Grant, Gerald T.; Liacouras, Peter; Susarla, Srinivas M.; Otake, Yoshito; Santiago, Gabriel; Armand, Mehran; Gordon, Chad R.

2016-01-01

Background The aesthetic and functional outcomes surrounding Le Fort–based, face-jaw-teeth transplantation have been suboptimal, often leading to posttransplant class II/III skeletal profiles, palatal defects, and “hybrid malocclusion.” Therefore, a novel technology—real-time cephalometry—was developed to provide the surgical team instantaneous, intraoperative knowledge of three-dimensional dentoskeletal parameters. Methods Mock face-jaw-teeth transplantation operations were performed on plastic and cadaveric human donor/recipient pairs (n = 2). Preoperatively, cephalometric landmarks were identified on donor/recipient skeletons using segmented computed tomographic scans. The computer-assisted planning and execution workstation tracked the position of the donor face-jaw-teeth segment in real time during the placement/inset onto recipient, reporting pertinent hybrid cephalometric parameters from any movement of donor tissue. The intraoperative data measured through real-time cephalometry were compared to posttransplant measurements for accuracy assessment. In addition, posttransplant cephalometric relationships were compared to planned outcomes to determine face-jaw-teeth transplantation success. Results Compared with postoperative data, the real-time cephalometry–calculated intraoperative measurement errors were 1.37 ± 1.11 mm and 0.45 ± 0.28 degrees for the plastic skull and 2.99 ± 2.24 mm and 2.63 ± 1.33 degrees for the human cadaver experiments. These results were comparable to the posttransplant relations to planned outcome (human cadaver experiment, 1.39 ± 1.81 mm and 2.18 ± 1.88 degrees; plastic skull experiment, 1.06 ± 0.63 mm and 0.53 ± 0.39 degrees). Conclusion Based on this preliminary testing, real-time cephalometry may be a valuable adjunct for adjusting and measuring “hybrid occlusion” in face-jaw-teeth transplantation and other orthognathic surgical procedures. PMID:26218382

Characterization of Hand Clenching in Human Sensorimotor Cortex Using High-, and Ultra-High Frequency Band Modulations of Electrocorticogram

PubMed Central

Jiang, Tianxiao; Liu, Su; Pellizzer, Giuseppe; Aydoseli, Aydin; Karamursel, Sacit; Sabanci, Pulat A.; Sencer, Altay; Gurses, Candan; Ince, Nuri F.

2018-01-01

Functional mapping of eloquent cortex before the resection of a tumor is a critical procedure for optimizing survival and quality of life. In order to locate the hand area of the motor cortex in two patients with low-grade gliomas (LGG), we recorded electrocorticogram (ECoG) from a 113 channel hybrid high-density grid (64 large contacts with diameter of 2.7 mm and 49 small contacts with diameter of 1 mm) while they executed hand clenching movements. We investigated the spatio-spectral characteristics of the neural oscillatory activity and observed that, in both patients, the hand movements were consistently associated with a wide spread power decrease in the low frequency band (LFB: 8–32 Hz) and a more localized power increase in the high frequency band (HFB: 60–280 Hz) within the sensorimotor region. Importantly, we observed significant power increase in the ultra-high frequency band (UFB: 300–800 Hz) during hand movements of both patients within a restricted cortical region close to the central sulcus, and the motor cortical “hand knob.” Among all frequency bands we studied, the UFB modulations were closest to the central sulcus and direct cortical stimulation (DCS) positive site. Both HFB and UFB modulations exhibited different timing characteristics at different locations. Power increase in HFB and UFB starting before movement onset was observed mostly at the anterior part of the activated cortical region. In addition, the spatial patterns in HFB and UFB indicated a probable postcentral shift of the hand motor function in one of the patients. We also compared the task related subband modulations captured by the small and large contacts in our hybrid grid. We did not find any significant difference in terms of band power changes. This study shows initial evidence that event-driven neural oscillatory activity recorded from ECoG can reach up to 800 Hz. The spatial distribution of UFB oscillations was found to be more focalized and closer to the central

Characterization of Hand Clenching in Human Sensorimotor Cortex Using High-, and Ultra-High Frequency Band Modulations of Electrocorticogram.

PubMed

Jiang, Tianxiao; Liu, Su; Pellizzer, Giuseppe; Aydoseli, Aydin; Karamursel, Sacit; Sabanci, Pulat A; Sencer, Altay; Gurses, Candan; Ince, Nuri F

2018-01-01

Functional mapping of eloquent cortex before the resection of a tumor is a critical procedure for optimizing survival and quality of life. In order to locate the hand area of the motor cortex in two patients with low-grade gliomas (LGG), we recorded electrocorticogram (ECoG) from a 113 channel hybrid high-density grid (64 large contacts with diameter of 2.7 mm and 49 small contacts with diameter of 1 mm) while they executed hand clenching movements. We investigated the spatio-spectral characteristics of the neural oscillatory activity and observed that, in both patients, the hand movements were consistently associated with a wide spread power decrease in the low frequency band (LFB: 8-32 Hz) and a more localized power increase in the high frequency band (HFB: 60-280 Hz) within the sensorimotor region. Importantly, we observed significant power increase in the ultra-high frequency band (UFB: 300-800 Hz) during hand movements of both patients within a restricted cortical region close to the central sulcus, and the motor cortical "hand knob." Among all frequency bands we studied, the UFB modulations were closest to the central sulcus and direct cortical stimulation (DCS) positive site. Both HFB and UFB modulations exhibited different timing characteristics at different locations. Power increase in HFB and UFB starting before movement onset was observed mostly at the anterior part of the activated cortical region. In addition, the spatial patterns in HFB and UFB indicated a probable postcentral shift of the hand motor function in one of the patients. We also compared the task related subband modulations captured by the small and large contacts in our hybrid grid. We did not find any significant difference in terms of band power changes. This study shows initial evidence that event-driven neural oscillatory activity recorded from ECoG can reach up to 800 Hz. The spatial distribution of UFB oscillations was found to be more focalized and closer to the central sulcus

Kinematic Features of Jaw and Lips Distinguish Symptomatic from Presymptomatic Stages of Bulbar Decline in Amyotrophic Lateral Sclerosis

ERIC Educational Resources Information Center

Bandini, Andrea; Green, Jordan R.; Wang, Jun; Campbell, Thomas F.; Zinman, Lorne; Yunusova, Yana

2018-01-01

Purpose: The goals of this study were to (a) classify speech movements of patients with amyotrophic lateral sclerosis (ALS) in presymptomatic and symptomatic phases of bulbar function decline relying solely on kinematic features of lips and jaw and (b) identify the most important measures that detect the transition between early and late bulbar…

Diagnostic value of NobelGuide to minimize the need for reconstructive surgery of jaws before implant placement: a review.

PubMed

Scotti, Roberto; Pellegrino, Gerardo; Marchetti, Claudio; Corinaldesi, Guiseppe; Ciocca, Leonardo

2010-01-01

To test if using a CAD/CAM system might reduce the necessity of bone augmentation in patients with atrophic maxillary arches before implant therapy. Twenty male and female patients consecutively scheduled for bone augmentation of the jaw before implant surgery were included in this study, with a total of 29 jaws (maxillary and mandibular) to analyze for the implant-supported fixed prosthesis group and 19 maxillary arches for the implant-supported removable prosthesis group. NobelGuide System (Nobel Biocare), Autocad System (Autodesk), and routine manual CT measurements of available bone were used in this study. The total results of the mean values of the fixed prosthesis group plus the mean values of the removable prosthesis group showed a statistically significant difference between the NobelGuide intervention score and both manual (P = .004) and Autocad (P = .001) measurements. The NobelGuide System represents a viable diagnostic device to reduce the entity or avoid bone reconstructive surgery before implant placements in the atrophic maxilla and mandible.

Retrospective cohort clinical investigation of a dental implant with a narrow diameter and short length for the partial rehabilitation of extremely atrophic jaws.

PubMed

Maló, Paulo S; de Araújo Nobre, Miguel A; Lopes, Armando V; Ferro, Ana S

2017-01-01

We investigated the short-term clinical outcomes of narrow-diameter short-length implants for the fixed-prosthetic partial rehabilitation of extremely resorbed jaws. Twenty-three patients requiring partial rehabilitations with narrow-platform short-length implants in any jaw were included in this study. In total, 30 implants 3.3 mm in diameter and 7 (n = 15 implants) or 8.5 (n = 15 implants) mm in length were inserted. The primary outcome measure was implant cumulative survival rate (CSR); the secondary outcome measures were marginal bone resorption at 1 and 3 years and the incidence of biologic and mechanical complications. Five patients (21.7%) with six implants (20%) were lost to follow-up. Two implants failed in two patients, yielding a CSR at 3 years of follow-up of 93.4%. The average (standard deviation) marginal bone resorption was 1.34 mm (0.95 mm) after the first year and 1.38 mm (0.78 mm) after the third year. Biologic complications occurred in three patients; mechanical complications occurred in three patients. Despite the limitations of the study, our findings show that the use of new narrow-diameter short-length implants for the rehabilitation of extremely atrophic regions is viable in the short-term, and can be considered a treatment alternative in extremely resorbed jaws.

"So Happy I Could Shout!" and "So Happy I Could Cry!" Dimorphous expressions represent and communicate motivational aspects of positive emotions.

PubMed

Aragón, Oriana R; Bargh, John A

2018-03-01

Happiness can be expressed through smiles. Happiness can also be expressed through physical displays that without context, would appear to be sadness (tears, downward turned mouths, and crumpled body postures) and anger (clenched jaws, snarled lips, furrowed brows, and pumped fists). These seemingly incongruent displays of happiness, termed dimorphous expressions, we propose, represent and communicate expressers' motivational orientations. When participants reported their own aggressive expressions in positive or negative contexts, their expressions represented positive or negative emotional experiences respectively, imbued with appetitive orientations (feelings of wanting to go). In contrast, reported sad expressions, in positive or negative contexts, represented positive and negative emotional experiences respectively, imbued with consummatory orientations (feelings of wanting to pause). In six additional experiments, participant observers interpreted that aggression displayed in positive contexts signalled happy-appetitive states, and sadness displayed in positive contexts signalled happy-consummatory states. Implications for the production and interpretation of emotion expressions are discussed.

A Comparison of Methods for Decoupling Tongue and Lower Lip from Jaw Movements in 3D Articulography

ERIC Educational Resources Information Center

Henriques, Rafael Neto; van Lieshout, Pascal

2013-01-01

Purpose: One popular method to study the motion of oral articulators is 3D electromagnetic articulography. For many studies, it is important to use an algorithm to decouple the motion of the tongue and the lower lip from the motion of the mandible. In this article, the authors describe and compare 4 methods for decoupling jaw motion by using 3D…

Converting Chemical Energy to Electricity through a Three-Jaw Mini-Generator Driven by the Decomposition of Hydrogen Peroxide.

PubMed

Xiao, Meng; Wang, Lei; Ji, Fanqin; Shi, Feng

2016-05-11

Energy conversion from a mechanical form to electricity is one of the most important research advancements to come from the horizontal locomotion of small objects. Until now, the Marangoni effect has been the only propulsion method to produce the horizontal locomotion to induce an electromotive force, which is limited to a short duration because of the specific property of surfactants. To solve this issue, in this article we utilized the decomposition of hydrogen peroxide to provide the propulsion for a sustainable energy conversion from a mechanical form to electricity. We fabricated a mini-generator consisting of three parts: a superhydrophobic rotator with three jaws, three motors to produce a jet of oxygen bubbles to propel the rotation of the rotator, and three magnets integrated into the upper surface of the rotator to produce the magnet flux. Once the mini-generator was placed on the solution surface, the motor catalyzed the decomposition of hydrogen peroxide. This generated a large amount of oxygen bubbles that caused the generator and integrated magnets to rotate at the air/water interface. Thus, the magnets passed under the coil area and induced a change in the magnet flux, thus generating electromotive forces. We also investigated experimental factors, that is, the concentration of hydrogen peroxide and the turns of the solenoid coil, and found that the mini-generator gave the highest output in a hydrogen peroxide solution with a concentration of 10 wt % and under a coil with 9000 turns. Through combining the stable superhydrophobicity and catalyst, we realized electricity generation for a long duration, which could last for 26 000 s after adding H2O2 only once. We believe this work provides a simple process for the development of horizontal motion and provides a new path for energy reutilization.

A novel whole tooth-in-jaw-bone culture of rat molars: morphological, immunohistochemical, and laser capture microdissection analysis.

PubMed

Chokechanachaisakul, Uraiwan; Kaneko, Tomoatsu; Yamanaka, Yusuke; Okiji, Takashi; Suda, Hideaki

2012-10-01

In conventional whole-tooth culture systems, limitation exists regarding maintenance of the vitality of the dental pulp, because this tissue is encased in rigid dentin walls that hinder nutrition supply. We here report a whole tooth-in-jaw-bone culture system of rat mandibular first molars, where transcardiac perfusion with culture medium was carried out before placement of the jaw bone into culture medium, aiming to facilitate longer time preservation of the dental pulp tissue. Following 7 days of culture, the pulp tissues were analyzed by histology and immunohistochemistry to ED2 (antiresident macrophage). ED2-positive macrophages were also analyzed for their Class II MHC, interleukin-6 (IL-6), and p53 mRNA expression levels by means of immune-laser capture microdissection (immune-LCM). Dentin sialophosphoprotein (DSPP) mRNA expression in odontobalstic layer was also examined by LCM. Teeth cultured following saline-perfusion and nonperfusion served as cultured controls. Normal teeth also served as noncultured controls. Histological examination demonstrated that the structure of the pulp tissue was well preserved in the medium-perfused explants in contrast to the cultured control groups. The Class II MHC, IL-6, and p53 mRNA expression levels of ED2-positive cells and DSPP expression levels of odontoblastic layer tissues in the pulp of medium-perfused explants were not significantly different from those in the noncultured normal teeth. In conclusion, the structural integrity and mRNA expression in the pulp were maintained at the in vivo level in the ex vivo whole tooth-in-jaw-bone culture system. The system may lay the foundation for studies aiming at defining further histological and molecular mechanism of the pulp. Copyright © 2012 Wiley Periodicals, Inc.

Regional odontodysplasia involving three quadrants of the jaws: a case report.

PubMed

Quinderé, Lêda Bezerra; Cavalcante, Roberta Barroso; Nonaka, Cassiano Francisco Weege; Miguel, Márcia Cristina da Costa; de Souza, Lélia Batista

2010-01-01

Regional odontodysplasia is a rare developmental anomaly of the teeth that affects enamel and dentin. Its etiology is unknown, but the most accepted theory refers to circulatory disorders associated with vascular nevi. An uncommon case of regional odontodysplasia involving three quadrants of the jaws is reported. An 8-year-old boy was referred to the authors' institution with lack of teeth as a major symptom. There was no hereditary anomaly in the family. Extraoral examination revealed a brown discoloration on the skin on the right side of the face, neck, and chest. Detailed intraoral examination showed hypoplastic and carious teeth. Fistulae and gingival overgrowth were also observed. Radiographically, the affected teeth presented the pathognomonic image of "ghost teeth." Conservative treatment was instituted.

A pharyngeal jaw evolutionary innovation facilitated extinction in Lake Victoria cichlids.

PubMed

McGee, Matthew D; Borstein, Samuel R; Neches, Russell Y; Buescher, Heinz H; Seehausen, Ole; Wainwright, Peter C

2015-11-27

Evolutionary innovations, traits that give species access to previously unoccupied niches, may promote speciation and adaptive radiation. Here, we show that such innovations can also result in competitive inferiority and extinction. We present evidence that the modified pharyngeal jaws of cichlid fishes and several marine fish lineages, a classic example of evolutionary innovation, are not universally beneficial. A large-scale analysis of dietary evolution across marine fish lineages reveals that the innovation compromises access to energy-rich predator niches. We show that this competitive inferiority shaped the adaptive radiation of cichlids in Lake Tanganyika and played a pivotal and previously unrecognized role in the mass extinction of cichlid fishes in Lake Victoria after Nile perch invasion. Copyright © 2015, American Association for the Advancement of Science.

The effect of oral motor activity on the athletic performance of professional golfers

PubMed Central

Ringhof, Steffen; Hellmann, Daniel; Meier, Florian; Etz, Eike; Schindler, Hans J.; Stein, Thorsten

2015-01-01

Human motor control is based on complex sensorimotor processes. Recent research has shown that neuromuscular activity of the craniomandibular system (CMS) might affect human motor control. In particular, improvements in postural stability and muscle strength have been observed as a result of voluntary jaw clenching. Potential benefits of jaw aligning appliances on muscle strength and golf performance have also been described. These reports are highly contradictory, however, and the oral motor task performed is often unclear. The purpose of our study was, therefore, to investigate the effect of submaximum biting on golf performance via shot precision and shot length over three different distances. Participants were 14 male professional golfers – seven with sleep bruxism and seven without – randomly performing golf shots over 60m, 160m, or driving distance while either biting on an oral splint or biting on their teeth; habitual jaw position served as the control condition. Statistical analysis revealed that oral motor activity did not systematically affect golf performance in respect of shot precision or shot length for 60m, 160 m, or driving distance. These findings were reinforced by impact variables such as club head speed and ball speed, which were also not indicative of significant effects. The results thus showed that the strength improvements and stabilizing effects described previously are, apparently, not transferable to such coordination-demanding sports as golf. This could be due to the divergent motor demands associated with postural control and muscle strength on the one hand and the complex coordination of a golf swing on the other. Interestingly, subjects without sleep bruxism performed significantly better at the short distance (60 m) than those with bruxism. Because of the multifactorial etiology of parafunctional CMS activity, conclusions about the need for dental treatment to improve sports performance are, however, completely unwarranted. PMID

Isolation of osteoprogenitors from human jaw periosteal cells: a comparison of two magnetic separation methods.

PubMed

Olbrich, Marcus; Rieger, Melanie; Reinert, Siegmar; Alexander, Dorothea

2012-01-01

Human jaw periosteum tissue contains osteoprogenitors that have potential for tissue engineering applications in oral and maxillofacial surgeries. To isolate osteoprogenitor cells from heterogeneous cell populations, we used the specific mesenchymal stem cell antigen-1 (MSCA-1) antibody and compared two magnetic separation methods. We analyzed the obtained MSCA-1(+) and MSCA-1(-) fractions in terms of purity, yield of positive/negative cells and proliferative and mineralization potentials. The analysis of cell viability after separation revealed that the EasySep method yielded higher viability rates, whereas the flow cytometry results showed a higher purity for the MACS-separated cell fractions. The mineralization capacity of the osteogenic induced MSCA-1(+) cells compared with the MSCA-1(-) controls using MACS was 5-fold higher, whereas the same comparison after EasySep showed no significant differences between both fractions. By analyzing cell proliferation, we detected a significant difference between the proliferative potential of the osteogenic cells versus untreated cells after the MACS and EasySep separations. The differentiated cells after MACS separation adjusted their proliferative capacity, whereas the EasySep-separated cells failed to do so. The protein expression analysis showed small differences between the two separation methods. Our findings suggest that MACS is a more suitable separation method to isolate osteoprogenitors from the entire jaw periosteal cell population.

Mechanics of biting in great white and sandtiger sharks.

PubMed

Ferrara, T L; Clausen, P; Huber, D R; McHenry, C R; Peddemors, V; Wroe, S

2011-02-03

Although a strong correlation between jaw mechanics and prey selection has been demonstrated in bony fishes (Osteichthyes), how jaw mechanics influence feeding performance in cartilaginous fishes (Chondrichthyes) remains unknown. Hence, tooth shape has been regarded as a primary predictor of feeding behavior in sharks. Here we apply Finite Element Analysis (FEA) to examine form and function in the jaws of two threatened shark species, the great white (Carcharodon carcharias) and the sandtiger (Carcharias taurus). These species possess characteristic tooth shapes believed to reflect dietary preferences. We show that the jaws of sandtigers and great whites are adapted for rapid closure and generation of maximum bite force, respectively, and that these functional differences are consistent with diet and dentition. Our results suggest that in both taxa, insertion of jaw adductor muscles on a central tendon functions to straighten and sustain muscle fibers to nearly orthogonal insertion angles as the mouth opens. We argue that this jaw muscle arrangement allows high bite forces to be maintained across a wider range of gape angles than observed in mammalian models. Finally, our data suggest that the jaws of sub-adult great whites are mechanically vulnerable when handling large prey. In addition to ontogenetic changes in dentition, further mineralization of the jaws may be required to effectively feed on marine mammals. Our study is the first comparative FEA of the jaws for any fish species. Results highlight the potential of FEA for testing previously intractable questions regarding feeding mechanisms in sharks and other vertebrates. Copyright © 2010 Elsevier Ltd. All rights reserved.

Interpretation of fusimotor activity in cat masseter nerve during reflex jaw movements.

PubMed Central

Gottlieb, S; Taylor, A

1983-01-01

Simultaneous recordings were made from fusimotor axons in the central ends of filaments of the masseter nerve, and from masseter and temporalis spindle afferents in the mesencephalic nucleus of the fifth cranial nerve in lightly anaesthetized cats. Fusimotor and alpha-motor units in the masseter nerve were differentiated on the basis of their response to passive ramp and hold stretches applied to the jaw. Spindle afferents were identified as primary or secondary according to their dynamic index after administration of suxamethonium. The activity of a given fusimotor unit during reflex movements of the jaw followed one of two distinct patterns: so-called 'tonic' units showed a general increase in activity during a movement, without detailed relation to lengthening or shortening, while 'modulated' units displayed a striking modulation of their activity with shortening, and were usually silent during subsequent lengthening. Comparison of the simultaneously recorded fusimotor and spindle afferent activity suggests that modulated units may be representative of a population of static fusimotor neurones, and tonic units of a population of dynamic fusimotor neurones. In these lightly anaesthetized animals, both primary and secondary spindle afferents showed increased firing during muscle shortening as well as during lengthening. This increase during shortening is not usually seen in conscious animals and reasons are given for the view that it is due to greater depression of alpha-motor activity than of static fusimotor activity during anaesthesia. The results are discussed in relation to the theories of 'alpha-gamma co-activation' and of 'servo-assistance'; and it is suggested that static fusimotor neurones provide a 'temporal template' of the intended movement, while dynamic fusimotor neurones set the required dynamic sensitivity to deviations from the intended movement pattern. PMID:6229627

Masticatory muscle architecture in a water-rat from Australasia (Murinae, Hydromys) and its implication for the evolution of carnivory in rodents.

PubMed

Fabre, P-H; Herrel, A; Fitriana, Y; Meslin, L; Hautier, L

2017-09-01

Murines are well known for their generalist diet, but several of them display specializations towards a carnivorous diet such as the amphibious Indo-Pacific water-rats. Despite the fact that carnivory evolved repeatedly in this group, few studies have investigated associated changes in jaw muscle anatomy and biomechanics. Here, we describe the jaw muscles and cranial anatomy of a carnivorous water-rat, Hydromys chrysogaster. The architecture of the jaw musculature of six specimens captured both on Obi and Papua were studied and described using dissections. We identified the origin and insertions of the jaw muscles, and quantified muscle mass, fiber length, physiological cross-sectional area, and muscle vectors for each muscle. Using a biomechanical model, we estimated maximum incisor and molar bite force at different gape angles. Finally, we conducted a 2D geometric morphometric analyses to compare jaw shape, mechanical potential, and diversity in lever-arm ratios for a set of 238 specimens, representative of Australo-Papuan carnivorous and omnivorous murids. Our study reveals major changes in the muscle proportions among Hydromys and its omnivorous close relative, Melomys. Hydromys was found to have large superficial masseter and temporalis muscles as well as a reduced deep masseter and zygomatico-mandibularis, highlighting major functional divergence among omnivorous and carnivorous murines. Changes in these muscles are also accompanied by changes in jaw shape and the lines of action of the muscles. A more vertically oriented masseter, reduced masseteric muscles, as well as an elongated jaw with proodont lower incisors are key features indicative of a reduced propalinality in carnivorous Hydromys. Differences in the fiber length of the masseteric muscles were also detected between Hydromys and Melomys, which highlight potential adaptations to a wide gape in Hydromys, allowing it to prey on larger animals. Using a biomechanical model, we inferred a greater bite

Three-dimensional virtual operations can facilitate complicated surgical planning for the treatment of patients with jaw deformities associated with facial asymmetry: a case report.

PubMed

Hara, Shingo; Mitsugi, Masaharu; Kanno, Takahiro; Nomachi, Akihiko; Wajima, Takehiko; Tatemoto, Yukihiro

2013-09-01

This article describes a case we experienced in which good postsurgical facial profiles were obtained for a patient with jaw deformities associated with facial asymmetry, by implementing surgical planning with SimPlant OMS. Using this method, we conducted LF1 osteotomy, intraoral vertical ramus osteotomy (IVRO), sagittal split ramus osteotomy (SSRO), mandibular constriction and mandibular border genioplasty. Not only did we obtain a class I occlusal relationship, but the complicated surgery also improved the asymmetry of the frontal view, as well as of the profile view, of the patient. The virtual operation using three-dimensional computed tomography (3D-CT) could be especially useful for the treatment of patients with jaw deformities associated with facial asymmetry.

Three-dimensional virtual operations can facilitate complicated surgical planning for the treatment of patients with jaw deformities associated with facial asymmetry: a case report

PubMed Central

Hara, Shingo; Mitsugi, Masaharu; Kanno, Takahiro; Nomachi, Akihiko; Wajima, Takehiko; Tatemoto, Yukihiro

2013-01-01

This article describes a case we experienced in which good postsurgical facial profiles were obtained for a patient with jaw deformities associated with facial asymmetry, by implementing surgical planning with SimPlant OMS. Using this method, we conducted LF1 osteotomy, intraoral vertical ramus osteotomy (IVRO), sagittal split ramus osteotomy (SSRO), mandibular constriction and mandibular border genioplasty. Not only did we obtain a class I occlusal relationship, but the complicated surgery also improved the asymmetry of the frontal view, as well as of the profile view, of the patient. The virtual operation using three-dimensional computed tomography (3D-CT) could be especially useful for the treatment of patients with jaw deformities associated with facial asymmetry. PMID:23907678

Evaluation of Spontaneous Bone Regeneration after Enucleation of Large Cysts of the Jaws using Radiographic Computed Software.

PubMed

Wagdargi, Shivaraj S; Rai, Kirthi Kumar; Arunkumar, K V; Katkol, Basavraj; Arakeri, Gururaj

2016-06-01

Spontaneous regeneration of bone is commonly seen in the small surgical defects caused by enucleation of cysts. However, in case of large surgical defects caused by the enucleation, spontaneous regeneration of bone is a rare phenomenon and it depends on factors, such as age of the patient, intact periosteum, and proper stabilization. The study included 16 patients, who reported to the department of oral and maxillofacial surgery with the complaint of pain and swelling in the jaws diagnosed as cyst. The sample included equal numbers of male and female subjects aged between 15 and 40 years. Panoramic radiographs were taken pre- and postoperatively on day 2 of the enucleation. The dimensions of the cyst were evaluated on the radiograph according to the proforma. Subsequent radiographs were taken at regular intervals of 1.5, 3, and 6 months using standard parameters and were analyzed using MCID™ analysis software of imaging research. Mean reduction was seen in up to 39 and 60% in the cystic cavity size and increase in the mean density up to 59 and 90.2% at 3 and 6 months intervals respectively. Spontaneous bone regeneration was seen even after primary closure of the large cystic defect without the need for placement of foreign substances or grafts and it also eliminated the complications resulting from placement of foreign substance. Further studies are required in a larger sample with longer follow-up durations to confirm the outcome of the present work for the benefit of patients. The present study depicted that spontaneous bone regeneration can occur with accepted results after simple enucleation of jaw cyst without the aid of any graft material. Hence, simple enucleation may be considered as a first line of treatment modality for cystic lesion of the jaws. This simplifies the surgical procedure, decreases the economic and biologic costs, and reduces the risk of postoperative complications. Follow-up is necessary along with patient's compliance for the success of

Finite element analysis to determine the stress distribution, displacement and safety factor on a microplate for the fractured jaw case

NASA Astrophysics Data System (ADS)

Pratama, Juan; Mahardika, Muslim

2018-03-01

Microplate is a connecting plate that can be used for jaw bone fixation. In the last two decades, microplate has been used so many times to help reconstruction of fractured jaw bone which is called mandibular bone or mandible bone. The plate is used to provide stable fixation of the fractured bone tissue during healing and reconstruction process. In this study Finite Element Analysis was used to predict the stress concentration and distribution on a microplate, displacement on the microplate and also to determine the safety factor of the microplate based on maximum allowable stress value, and finally to ascertain whether microplate is safe to use or not. The microplate was produced from punching process using titanium grade 1 (pure titanium) as material with a thickness of 500 µm. The results of the research indicated that the microplate was safe to use according to the maximum stress around the hole, displacement around the hole and also the safety factor of the microplate.

Existing data sources for clinical epidemiology: Scandinavian Cohort for osteonecrosis of the jaw – work in progress and challenges

PubMed Central

Schiodt, Morten; Larsson Wexell, Cecilia; Herlofson, Bente Brokstad; Giltvedt, Karen Marie; Norholt, Sven Erik; Ehrenstein, Vera

2015-01-01

Osteonecrosis of the jaw (ONJ) is a severe side effect associated with antiresorptive treatment. Monitoring of ONJ using routine databases in Scandinavian countries is a challenge owing to lack of valid algorithms and to heterogeneous referral practices. The aim of this paper is to describe the process of establishing a Scandinavian ONJ Cohort enrolling all ONJ cases related to antiresorptive treatment arising in Denmark, Norway, and Sweden between 2011 and 2019. The initial purpose of the cohort is to support an ongoing pharmacovigilance study of denosumab and zoledronic acid in Denmark, Norway, and Sweden. The three countries, with their 199 clinics, departments, and units of oral and maxillofacial surgery, both hospital-based and freestanding, differ somewhat in referral practices of the ONJ patients. By directly contacting all providers of care to ONJ patients in the three countries, we established a network for reporting incident cases to each country’s research database directly or through a member of the Scandinavian ONJ task force as a liaison. The task force includes a Scandinavian coordinator and three national coordinators collaborating directly with the clinics. A uniform ONJ registration form has been developed, and the relevant medical community has been informed either directly or through presentations at professional meetings. A website with study information is published in each country, and data entry is ongoing. This large-scale systematic uniform registration of ONJ cases in Denmark, Norway, and Sweden, with an underlying total population of more than 20 million people, merged into the Scandinavian ONJ Cohort, will contribute to better knowledge and understanding of this challenging group of patients, and ultimately, help improve patient care. The Scandinavian ONJ Cohort as a whole and its component national ONJ research databases may offer the potential for large-scale multinational intervention and safety studies in the future. PMID:25657594

The Redox Balance in Erythrocytes, Plasma, and Periosteum of Patients with Titanium Fixation of the Jaw

PubMed Central

Borys, Jan; Maciejczyk, Mateusz; Krȩtowski, Adam J.; Antonowicz, Bozena; Ratajczak-Wrona, Wioletta; Jabłońska, Ewa; Załęski, Piotr; Waszkiel, Danuta; Ładny, Jerzy R.; Żukowski, Piotr; Zalewska, Anna

2017-01-01

Titanium miniplates and screws are commonly used for fixation of jaw fractured or osteotomies. Despite the opinion of their biocompatibility, in clinical practice symptoms of chronic inflammation around the fixation develop in some patients, even many years after the application of miniplates and screws. The cause of these complications is still an unanswered question. Taking into account that oxidative stress is one of the toxic action of titanium, we have evaluated the antioxidant barrier as well as oxidative stress in the erythrocytes, plasma and periosteum covering the titanium fixation of the jaw. The study group was composed of 32 patients aged 20–30 with inserted miniplates and screws. The antioxidant defense: catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase-1 (SOD1), uric acid (UA), total antioxidant capacity (TAC), as well as oxidative damage products: advanced oxidation protein products (AOPP), advanced glycation end products (AGE), dityrosine, kynurenine, N-formylkynurenine, tryptophan, malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), total oxidant status (TOS), and oxidative status index (OSI) were evaluated. SOD1 activity (↓37%), and tryptophan levels (↓34%) showed a significant decrease while AOPP (↑25%), TOS (↑80%) and OSI (↑101%) were significantly elevated in maxillary periosteum of patients who underwent bimaxillary osteotomies as compared to the control group. SOD-1 (↓55%), TAC (↓58.6%), AGE (↓60%) and N-formylkynurenine (↓34%) was statistically reduced while AOPP (↑38%), MDA (↑29%), 4-HNE (↑114%), TOS (↑99%), and OSI (↑381%) were significantly higher in the mandibular periosteum covering miniplates/screw compared with the control tissues. There were no correlations between antioxidants and oxidative stress markers in the periosteum of all patients and the blood. As exposure to the Ti6Al4V titanium alloy leads to disturbances of redox balance in the periosteum surrounding titanium implants of the

Stress assessment using hair cortisol of kangaroos affected by the lumpy jaw disease.

PubMed

Sotohira, Yukari; Suzuki, Kazuyuki; Sano, Tadashi; Arai, Chigusa; Asakawa, Mitsuhiko; Hayashi, Hideaki

2017-05-03

The aim of this study was to objectively assess stress of kangaroos affected by lumpy jaw disease (LJD) using plasma and hair cortisol concentrations. The plasma and hair samples were collected from kangaroos with LJD and healthy controls. Collected hair samples were extracted with methanol after washing with isopropanol, following which they were processed with the cortisol enzyme immunoassay kit. The plasma cortisol concentration of LJD animals tended to be higher than that of the control. Ventral hair cortisol, but not dorsal hair, of LJD animals was significantly higher than that of the control. In conclusion, stress in kangaroos infected with LJD could be assessed by measuring ventral hair cortisol.

The Measurement of Airflow Using Singing Helmet That Allows Free Movement of the Jaw.

PubMed

Jiang, Jack J; Hanna, Rewais B; Willey, Malachi V; Rieves, Adam

2016-11-01

Airflow measurement is a useful method of evaluating laryngeal physiology. We introduce a noninvasive device that measures airflow without restricting jaw movement or requiring phonation into a mouthpiece, thus facilitating measurement during singing and connected speech. Validation and human subject trials were conducted. Airflow measurements were obtained from 16 male and 16 female subjects during singing, speech, and constant vowel production tasks. A similar helmet was designed by Stevens and Mead in 1968. The new device validity was evaluated by comparing the measured volume of air to a known volume of administered air using a calibration syringe. Subjects were asked to voice sustained vowels at low, medium, and high vocal intensity, read two sentences at a conversational volume, and perform different singing exercises while airflow was recorded. The device accurately and reliably measured airflow with mean airflow values falling within previously published ranges. There was an experimentally determined response time of 0.173 ± 0.014 seconds. Subjects were able to comfortably perform speech and singing exercises. Male subjects had higher airflow for all sustained vowels (P < 0.05). Airflow was higher for abduction rather than adduction sentences (P < 0.05). No other portable device has been shown to measure airflow during singing and speech while allowing for free movement of the jaw. This device provides a more natural environment to measure airflow that could be used to help evaluate laryngeal function and aid in singing training. Copyright © 2016 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Cranial morphology and bite force in Chamaeleolis lizards--adaptations to molluscivory?

PubMed

Herrel, Anthony; Holanova, Veronika

2008-01-01

Anolis lizards have become a model system for the study of adaptive radiations as species with similar morphologies occupying similar habitats have arisen independently on all the larger islands in the Caribbean. However, on both, Cuba and Hispaniola unique forms have evolved that seemingly have no counterparts on any of the other Caribbean islands. Anoles of the genus Chamaeleolis comprise such a unique form and have been termed 'twig giants' because of their cryptic life style, slow locomotor mode, and short limbs. However, some of the most unusual features of these lizards are their large heads and molluscivorous diet. Here, we compare head shape, bite force, and muscle structure among sexes and age classes of Chamaeleolis lizards with Anolis crown giants. Our data show that Chamaeleolis lizards have a dramatically different head shape characterized by tall heads with a pronounced temporal ridge and long snouts. Analyses of bite force, surprisingly, show no differences between adult Chamaeleolis and Anolis crown giants. Juveniles of Chamaeleolis, however, have very tall heads for their size and bite harder than Anolis juveniles do. This can be related to the propensity of juveniles of this genus to eat snails, food items for which high bite forces are crucial. This observation is corroborated by the presence of well-developed jaw adductors in juveniles. Thus, our data suggest that the unusual phenotype of adults with large and tall heads may be due to selection on the juvenile life history stages.

Bisphosphonate associated osteonecrosis of the jaw.

PubMed

Khan, Aliya A; Sándor, George K B; Dore, Edward; Morrison, Archibald D; Alsahli, Mazen; Amin, Faizan; Peters, Edmund; Hanley, David A; Chaudry, Sultan R; Lentle, Brian; Dempster, David W; Glorieux, Francis H; Neville, Alan J; Talwar, Reena M; Clokie, Cameron M; Mardini, Majd Al; Paul, Terri; Khosla, Sundeep; Josse, Robert G; Sutherland, Susan; Lam, David K; Carmichael, Robert P; Blanas, Nick; Kendler, David; Petak, Steven; Ste-Marie, Louis Georges; Brown, Jacques; Evans, A Wayne; Rios, Lorena; Compston, Juliet E

2009-03-01

In 2003, the first reports describing osteonecrosis of the jaw (ONJ) in patients receiving bisphosphonates (BP) were published. These cases occurred in patients with cancer receiving high-dose intravenous BP; however, 5% of the cases were in patients with osteoporosis receiving low-dose bisphosphonate therapy. We present the results of a systematic review of the incidence, risk factors, diagnosis, prevention, and treatment of BP associated ONJ. We conducted a comprehensive literature search for relevant studies on BP associated ONJ in oncology and osteoporosis patients published before February 2008.All selected relevant articles were sorted by area of focus. Data for each area were abstracted by 2 independent reviewers. The results showed that the diagnosis is made clinically. Prospective data evaluating the incidence and etiologic factors are very limited. In oncology patients receiving high-dose intravenous BP, ONJ appears to be dependent on the dose and duration of therapy, with an estimated incidence of 1%-12% at 36 months of exposure. In osteoporosis patients, it is rare, with an estimated incidence < 1 case per 100,000 person-years of exposure. The incidence of ONJ in the general population is not known. Currently, there is insufficient evidence to confirm a causal link between low-dose BP use in the osteoporosis patient population and ONJ. We concluded BP associated ONJ is associated with high-dose BP therapy primarily in the oncology patient population. Prevention and treatment strategies are currently based on expert opinion and focus on maintaining good oral hygiene and conservative surgical intervention.

Dynamic finite element simulation of dental prostheses during chewing using muscle equivalent force and trajectory approaches.

PubMed

Razaghi, Reza; Biglari, Hasan; Karimi, Alireza

2017-05-01

The long-term application of dental prostheses inside the bone has a narrow relation to its biomechanical performance. Chewing is the most complicated function of a dental implant as it implements different forces to the implant at various directions. Therefore, a suitable holistic modelling of the jaw bone, implant, food, muscles, and their forces would be deemed significant to figure out the durability as well as functionality of a dental implant while chewing. So far, two approaches have been proposed to employ the muscle forces into the Finite Element (FE) models, i.e. Muscle Equivalent Force (MEF) and trajectory. This study aimed at propounding a new three-dimensional dynamic FE model based on two muscle forces modelling approaches in order to investigate the stresses and deformations in the dental prosthesis as well as maxillary bone during the time of chewing a cornflakes bio. The results revealed that both contact and the maximum von Mises stress in the implant and bones for trajectory approach considerably exceed those of the MEF. The maximum stresses, moreover, are located around the neck of implant which should be both clinically and structurally strong enough to functionally maintain the bone-implant interface. In addition, a higher displacement due to compressive load is observed for the implant head in trajectory approach. The results suggest the benefits provided by trajectory approach since MEF approach would significantly underestimate the stresses and deformations in both the dental prosthesis and bones.

Feeding biomechanics and theoretical calculations of bite force in bull sharks (Carcharhinus leucas) during ontogeny.

PubMed

Habegger, Maria L; Motta, Philip J; Huber, Daniel R; Dean, Mason N

2012-12-01

Evaluations of bite force, either measured directly or calculated theoretically, have been used to investigate the maximum feeding performance of a wide variety of vertebrates. However, bite force studies of fishes have focused primarily on small species due to the intractable nature of large apex predators. More massive muscles can generate higher forces and many of these fishes attain immense sizes; it is unclear how much of their biting performance is driven purely by dramatic ontogenetic increases in body size versus size-specific selection for enhanced feeding performance. In this study, we investigated biting performance and feeding biomechanics of immature and mature individuals from an ontogenetic series of an apex predator, the bull shark, Carcharhinus leucas (73-285cm total length). Theoretical bite force ranged from 36 to 2128N at the most anterior bite point, and 170 to 5914N at the most posterior bite point over the ontogenetic series. Scaling patterns differed among the two age groups investigated; immature bull shark bite force scaled with positive allometry, whereas adult bite force scaled isometrically. When the bite force of C. leucas was compared to those of 12 other cartilaginous fishes, bull sharks presented the highest mass-specific bite force, greater than that of the white shark or the great hammerhead shark. A phylogenetic independent contrast analysis of anatomical and dietary variables as determinants of bite force in these 13 species indicated that the evolution of large adult bite forces in cartilaginous fishes is linked predominantly to the evolution of large body size. Multiple regressions based on mass-specific standardized contrasts suggest that the evolution of high bite forces in Chondrichthyes is further correlated with hypertrophication of the jaw adductors, increased leverage for anterior biting, and widening of the head. Lastly, we discuss the ecological significance of positive allometry in bite force as a possible

Possible Interbreeding in Late Italian Neanderthals? New Data from the Mezzena Jaw (Monti Lessini, Verona, Italy)

PubMed Central

Condemi, Silvana; Mounier, Aurélien; Giunti, Paolo; Lari, Martina; Caramelli, David; Longo, Laura

2013-01-01

In this article we examine the mandible of Riparo Mezzena a Middle Paleolithic rockshelter in the Monti Lessini (NE Italy, Verona) found in 1957 in association with Charentian Mousterian lithic assemblages. Mitochondrial DNA analysis performed on this jaw and on other cranial fragments found at the same stratigraphic level has led to the identification of the only genetically typed Neanderthal of the Italian peninsula and has confirmed through direct dating that it belongs to a late Neanderthal. Our aim here is to re-evaluate the taxonomic affinities of the Mezzena mandible in a wide comparative framework using both comparative morphology and geometric morphometrics. The comparative sample includes mid-Pleistocene fossils, Neanderthals and anatomically modern humans. This study of the Mezzena jaw shows that the chin region is similar to that of other late Neanderthals which display a much more modern morphology with an incipient mental trigone (e.g. Spy 1, La Ferrassie, Saint-Césaire). In our view, this change in morphology among late Neanderthals supports the hypothesis of anatomical change of late Neanderthals and the hypothesis of a certain degree of interbreeding with AMHs that, as the dating shows, was already present in the European territory. Our observations on the chin of the Mezzena mandible lead us to support a non abrupt phylogenetic transition for this period in Europe. PMID:23544098

Fast and Powerful: Biomechanics and Bite Forces of the Mandibles in the American Cockroach Periplaneta americana

PubMed Central

Weihmann, Tom; Reinhardt, Lars; Weißing, Kevin; Siebert, Tobias; Wipfler, Benjamin

2015-01-01

Knowing the functionality and capabilities of masticatory apparatuses is essential for the ecological classification of jawed organisms. Nevertheless insects, especially with their outstanding high species number providing an overwhelming morphological diversity, are notoriously underexplored with respect to maximum bite forces and their dependency on the mandible opening angles. Aiming for a general understanding of insect biting, we examined the generalist feeding cockroach Periplaneta americana, characterized by its primitive chewing mouth parts. We measured active isometric bite forces and passive forces caused by joint resistance over the entire mandibular range with a custom-built 2D force transducer. The opening angle of the mandibles was quantified by using a video system. With respect to the effective mechanical advantage of the mandibles and the cross-section areas, we calculated the forces exerted by the mandible closer muscles and the corresponding muscle stress values. Comparisons with the scarce data available revealed close similarities of the cockroaches’ mandible closer stress values (58 N/cm2) to that of smaller specialist carnivorous ground beetles, but strikingly higher values than in larger stag beetles. In contrast to available datasets our results imply the activity of faster and slower muscle fibres, with the latter becoming active only when the animals chew on tough material which requires repetitive, hard biting. Under such circumstances the coactivity of fast and slow fibres provides a force boost which is not available during short-term activities, since long latencies prevent a specific effective employment of the slow fibres in this case. PMID:26559671

Canadian consensus practice guidelines for bisphosphonate associated osteonecrosis of the jaw.

PubMed

Khan, Aliya A; Sándor, George K B; Dore, Edward; Morrison, Archibald D; Alsahli, Mazen; Amin, Faizan; Peters, Edmund; Hanley, David A; Chaudry, Sultan R; Dempster, David W; Glorieux, Francis H; Neville, Alan J; Talwar, Reena M; Clokie, Cameron M; Al Mardini, Majd; Paul, Terri; Khosla, Sundeep; Josse, Robert G; Sutherland, Susan; Lam, David K; Carmichael, Robert P; Blanas, Nick; Kendler, David; Petak, Steven; St-Marie, Louis Georges; Brown, Jacques; Evans, A Wayne; Rios, Lorena; Compston, Juliet E

2008-07-01

Following publication of the first reports of osteonecrosis of the jaw (ONJ) in patients receiving bisphosphonates in 2003, a call for national multidisciplinary guidelines based upon a systematic review of the current evidence was made by the Canadian Association of Oral and Maxillofacial Surgeons (CAOMS) in association with national and international societies concerned with ONJ. The purpose of the guidelines is to provide recommendations regarding diagnosis, identification of at-risk patients, and prevention and management strategies, based on current evidence and consensus. These guidelines were developed for medical and dental practitioners as well as for oral pathologists and related specialists. The multidisciplinary task force established by the CAOMS reviewed all relevant areas of research relating to ONJ associated with bisphosphonate use and completed a systematic review of current literature. These evidence-based guidelines were developed utilizing a structured development methodology. A modified Delphi consensus process enabled consensus among the multidisciplinary task force members. These guidelines have since been reviewed by external experts and endorsed by national and international medical, dental, oral surgery, and oral pathology societies. RECOMMENDATIONS regarding diagnosis, prevention, and management of ONJ were made following analysis of all current data pertaining to this condition. ONJ has many etiologic factors including head and neck irradiation, trauma, periodontal disease, local malignancy, chemotherapy, and glucocorticoid therapy. High-dose intravenous bisphosphonates have been identified as a risk factor for ONJ in the oncology patient population. Low-dose bisphosphonate use in patients with osteoporosis or other metabolic bone disease has not been causally linked to the development of ONJ. Prevention, staging, and treatment recommendations are based upon collective expert opinion and current data, which has been limited to case

SU-E-T-320: Dosimetric Evaluation of Intracranial Stereotactic Radiotherapy Plans Using Jaws-Only Collimation On a LINAC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mistry, N; Kim, A; Schaum, J

2015-06-15

Purpose: To evaluate the dosimetry of cranial stereotactic radiotherapy (SRT) plans using jaws-only collimation on linac that meets appropriate TG-142 tolerances. Methods: Seventeen spherical targets were generated in the center of a head phantom with diameters ranging from 8 mm to 40 mm. Plans balanced treatment time with dose gradient and conformity using 13 static fields and 3 couch angles: 9 non-opposed and coplanar fields and 4 non-coplanar fields. The symmetrical jaws field size was target diameter plus 2 mm. The prescription (Rx) was 7 Gy per fraction to the 80% isodose line. Two plans were created for each target:more » one kept the collimator at 0° (C0), one adjusted the collimator angle 40° for each field to create a 360° sweep over the 9 coplanar fields (CR).Conformity of the Rx to the target was evaluated using a ratio of Rx to target volume (PITV). Heterogeneity was determined using a ratio of maximum dose to Rx dose. Falloff was scored using CGIg: the difference of effective radii of spheres equal to half and full Rx volumes. Results: All plans met RTOG SRS criteria for conformity and heterogeneity. The use of collimator rotation improved conformity by 3.2% on average, the mean PITV was 1.7±0.1 for C0 plans and 1.6±0.1 for CR. Mean heterogeneity was 1.25±0.0 for both C0 and CR. The mean CGIg was 75.9±16.4 for C0 plans and 74.4±17.0 for CR; with a mean dose falloff degradation of 2.5% by CR. Conclusion: Clinically acceptable SRT plans for spherical targets were created using jaws-only collimation with static fields. The addition of sweeping collimator rotation improves conformity at the expense of gradient. This technique can expand the availability of SRT to patients especially to those who cannot travel to a facility with a dedicated stereotactic radiosurgery machine.« less

Multigenic Delineation of Lower Jaw Deformity in Triploid Atlantic Salmon (Salmo salar L.)

PubMed Central

Amoroso, Gianluca; Ventura, Tomer; Elizur, Abigail; Carter, Chris G.

2016-01-01

Lower jaw deformity (LJD) is a skeletal anomaly affecting farmed triploid Atlantic salmon (Salmo salar L.) which leads to considerable economic losses for industry and has animal welfare implications. The present study employed transcriptome analysis in parallel with real-time qPCR techniques to characterise for the first time the LJD condition in triploid Atlantic salmon juveniles using two independent sample sets: experimentally-sourced salmon (60 g) and commercially produced salmon (100 g). A total of eleven genes, some detected/identified through the transcriptome analysis (fbn2, gal and gphb5) and others previously determined to be related to skeletal physiology (alp, bmp4, col1a1, col2a1, fgf23, igf1, mmp13, ocn), were tested in the two independent sample sets. Gphb5, a recently discovered hormone, was significantly (P < 0.05) down-regulated in LJD affected fish in both sample sets, suggesting a possible hormonal involvement. In-situ hybridization detected gphb5 expression in oral epithelium, teeth and skin of the lower jaw. Col2a1 showed the same consistent significant (P < 0.05) down-regulation in LJD suggesting a possible cartilaginous impairment as a distinctive feature of the condition. Significant (P < 0.05) differential expression of other genes found in either one or the other sample set highlighted the possible effect of stage of development or condition progression on transcription and showed that anomalous bone development, likely driven by cartilage impairment, is more evident at larger fish sizes. The present study improved our understanding of LJD suggesting that a cartilage impairment likely underlies the condition and col2a1 may be a marker. In addition, the involvement of gphb5 urges further investigation of a hormonal role in LJD and skeletal physiology in general. PMID:27977809

Multigenic Delineation of Lower Jaw Deformity in Triploid Atlantic Salmon (Salmo salar L.).

PubMed

Amoroso, Gianluca; Ventura, Tomer; Cobcroft, Jennifer M; Adams, Mark B; Elizur, Abigail; Carter, Chris G

2016-01-01

Lower jaw deformity (LJD) is a skeletal anomaly affecting farmed triploid Atlantic salmon (Salmo salar L.) which leads to considerable economic losses for industry and has animal welfare implications. The present study employed transcriptome analysis in parallel with real-time qPCR techniques to characterise for the first time the LJD condition in triploid Atlantic salmon juveniles using two independent sample sets: experimentally-sourced salmon (60 g) and commercially produced salmon (100 g). A total of eleven genes, some detected/identified through the transcriptome analysis (fbn2, gal and gphb5) and others previously determined to be related to skeletal physiology (alp, bmp4, col1a1, col2a1, fgf23, igf1, mmp13, ocn), were tested in the two independent sample sets. Gphb5, a recently discovered hormone, was significantly (P < 0.05) down-regulated in LJD affected fish in both sample sets, suggesting a possible hormonal involvement. In-situ hybridization detected gphb5 expression in oral epithelium, teeth and skin of the lower jaw. Col2a1 showed the same consistent significant (P < 0.05) down-regulation in LJD suggesting a possible cartilaginous impairment as a distinctive feature of the condition. Significant (P < 0.05) differential expression of other genes found in either one or the other sample set highlighted the possible effect of stage of development or condition progression on transcription and showed that anomalous bone development, likely driven by cartilage impairment, is more evident at larger fish sizes. The present study improved our understanding of LJD suggesting that a cartilage impairment likely underlies the condition and col2a1 may be a marker. In addition, the involvement of gphb5 urges further investigation of a hormonal role in LJD and skeletal physiology in general.

Influence of jaw tracking in intensity-modulated and volumetric-modulated arc radiotherapy for head and neck cancers: a dosimetric study.

PubMed

Mani, Karthick Raj; Upadhayay, Sagar; Das, K J Maria

2017-03-01

To Study the dosimetric advantage of the Jaw tracking technique in intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) for Head and Neck Cancers. We retrospectively selected 10 previously treated head and neck cancer patients stage (T1/T2, N1, M0) in this study. All the patients were planned for IMRT and VMAT with simultaneous integrated boost technique. IMRT and VMAT plans were performed with jaw tracking (JT) and with static jaw (SJ) technique by keeping the same constraints and priorities for a particular patient. Target conformity, dose to the critical structures and low dose volumes were recorded and analyzed for IMRT and VMAT plans with and without JT for all the patients. The conformity index average of all patients followed by standard deviation ([Formula: see text] ± [Formula: see text]) of the JT-IMRT, SJ-IMRT, JT-VMAT, and SJ-VMAT were 1.72 ± 0.56, 1.67 ± 0.57, 1.83 ± 0.65, and 1.85 ± 0.64, and homogeneity index were 0.059 ± 0.05, 0.064 ± 0.05, 0.064 ± 0.04, and 0.064 ± 0.05. JT-IMRT shows significant mean reduction in right parotid and left parotid shows of 7.64% (p < 0.001) and 7.45% (p < 0.001) compare to SJ-IMRT. JT-IMRT plans also shows considerable dose reduction to thyroid, inferior constrictors, spinal cord and brainstem compared to the SJ-IMRT plans. Significant dose reductions were observed for critical structure in the JT-IMRT compared to SJ-IMRT technique. In JT-VMAT plans dose reduction to the critical structure were not significant compared to the SJ-IMRT due to relatively lesser monitor units.

Chromosome evaluation of Angus calves with unilateral congenital cleft lip and jaw (cheilognathoschisis).

PubMed

Swartz, H A; Vogt, D W; Kintner, L D

1982-04-01

Two purebred Angus calves with unilateral cleft lip and jaw were karyotyped and anatomically described. Both calves, 1 male and 1 female, were from the same farm and were born in March and April 1980. The defect was most pronounced in the female calf. Both calves exhibited an elevated midline of the hard palate. The female calf also manifested characteristics indicative of proportionate dwarfism. Karyotypes were constructed after a 72-hour culture of peripheral blood. The 2N number was 60 with no apparent chromosome abnormality. The coefficient of relationship between the 2 affected calves was calculated to be 0.78%. The cause of the defect could not be ascertained from the limited data available.

Ecomorphology of the moray bite: relationship between dietary extremes and morphological diversity.

PubMed

Mehta, Rita S

2009-01-01

The pharyngeal jaws of moray eels function exclusively to transport prey from the oral jaws into the esophagus. This functional innovation in the moray pharyngeal jaw system occurred through the loss of some ancestral functions that presumably included prey processing. Therefore, the oral jaws of morays are used to capture and process prey. Dietary accounts suggest that morays can be categorized as either piscivorous or durophagous in feeding habits. These extreme feeding specializations that select for conflicting biomechanical demands on the oral jaws should result in two discrete clusters of cranial form and diet in morphospace. When functional characters underlying the oral jaws were examined for 10 muraenid species, piscivorous and durophagous morays occupied distinct areas of morphospace. Piscivores exhibited longer jaws, narrower heads, and long recurved teeth, while durophagous morays exhibited shorter jaws, greater dentary depths, and short blunt teeth. Durophagous morays process prey in their oral jaws, and their jaw-opening and jaw-closing ratios, along with their enlarged adductors, revealed jaws modified for force transmission. Pharyngeal jaw characters also separated moray species into different areas of morphospace. For example, Gymnomuraena zebra, a molluscivore, had more teeth on its pharyngobranchials than all other morays, and these teeth were long and thin compared with those of piscivores. The overall patterns of morphological variation corresponded well with moray dietary breadth. In addition, the range of jaw-opening and jaw-closing ratios revealed that for a clade of obligate carnivores, morays exhibit diverse biting behaviors.

On occlusal forces in dentitions with implant-supported fixed cantilever prostheses.

PubMed

Falk, H

1990-01-01

The main aims of this thesis were (1) to study the functional characteristics of dentitions with mandibular implant-supported fixed cantilever prostheses - IFCP s- occluding with complete dentures, (2) to study in detail the magnitudes and distributions of axially directed closing and chewing forces in such dentitions, (3) to study the influence of number and distribution of occlusal contacts on the magnitude and distribution of closing and chewing forces, (4) to assess the vertical bending moment and the resulting vertical bending stress in the cantilever joints and (5) to find out whether the force distribution over the cantilever beams and the resulting vertical bending stress in the cantilever joint are influenced by the type of prosthetic construction in the opposing jaw. Closing and chewing forces were registered in altogether seventeen subjects by means of miniature strain gauge transducers mounted bilaterally and symmetrically in performed matrices in prosthetic appliances. Four, six or eight transducers, evenly distributed over the tooth-arch, permitted registrations of axially directed occlusal forces in several occluding areas simultaneously. In Papers I-IV, the implant-supported prostheses were installed in the mandible and occluded with complete dentures. In Paper V, group A, the fixture-supported prostheses were installed in the maxilla and occluded with tooth-supported fixed partial dentures whereas in group B, the arrangements were analogous to those in Papers I-IV. All subjects exhibited a rhythmic chewing pattern and preferred one side for chewing although both sides were used. Most chewing sequences were terminated with swallowing with occlusal force development. The mean total forces acting over the tooth-arch varied somewhat between groups and occlusal arrangements but averaged 350 and 170 N for closing and chewing respectively. Closing and chewing forces increased distally along the cantilever beams when occluding with complete dentures and

Inactivation of the Anterior Cingulate Cortex Impairs Extinction of Rabbit Jaw Movement Conditioning and Prevents Extinction-Related Inhibition of Hippocampal Activity

ERIC Educational Resources Information Center

Griffin, Amy L.; Berry, Stephen D.

2004-01-01

Although past research has highlighted the involvement of limbic structures such as the anterior cingulate cortex (ACC) and hippocampus in learning, few have addressed the nature of their interaction. The current study of rabbit jaw movement conditioning used a combination of reversible lesions and electrophysiology to examine the involvement of…

Developmental studies of the lamprey and hierarchical evolutionary steps towards the acquisition of the jaw

PubMed Central

Kuratani, Shigeru

2005-01-01

The evolution of animal morphology can be understood as a series of changes in developmental programs. Among vertebrates, some developmental stages are conserved across species, representing particular developmental constraints. One of the most conserved stages is the vertebrate pharyngula, in which similar embryonic morphology is observed and the Hox code is clearly expressed. The oral developmental program also appears to be constrained to some extent, as both its morphology and the the Hox-code-default state of the oropharyngeal region are well conserved between the lamprey and gnathostome embryos. These features do not by themselves explain the evolution of jaws, but should be regarded as a prerequisite for evolutionary diversification of the mandibular arch. By comparing the pharyngula morphology of the lamprey and gnathostomes, it has become clear that the oral pattern is not entirely identical; in particular, the positional differentiation of the rostral ectomesenchyme is shifted between these animals. Therefore, the jaw seems to have arisen as an evolutionary novelty by overriding ancestral constraints, a process in which morphological homologies are partially lost. This change involves the heterotopic shift of tissue interaction, which appears to have been preceded by the transition from monorhiny to diplorhiny, as well as separation of the hypophysis. When gene expression patterns are compared between the lamprey and gnathostomes, cell-autonomously functioning genes tend to be associated with identical cell types or equivalent anatomical domains, whereas growth-factor-encoding genes have changed their expression domains during evolution. Thus, the heterotopic evolution may be based on changes in the regulation of signalling-molecule-encoding genes. PMID:16313390

Three-dimensional evaluation of human jaw bone microarchitecture: correlation between the microarchitectural parameters of cone beam computed tomography and micro-computer tomography.

PubMed

Kim, Jo-Eun; Yi, Won-Jin; Heo, Min-Suk; Lee, Sam-Sun; Choi, Soon-Chul; Huh, Kyung-Hoe

2015-12-01

To evaluate the potential feasibility of cone beam computed tomography (CBCT) in the assessment of trabecular bone microarchitecture. Sixty-eight specimens from four pairs of human jaw were scanned using both micro-computed tomography (micro-CT) of 19.37-μm voxel size and CBCT of 100-μm voxel size. The correlation of 3-dimensional parameters between CBCT and micro-CT was evaluated. All parameters, except bone-specific surface and trabecular thickness, showed linear correlations between the 2 imaging modalities (P < .05). Among the parameters, bone volume, percent bone volume, trabecular separation, and degree of anisotropy (DA) of CBCT images showed strong correlations with those of micro-CT images. DA showed the strongest correlation (r = 0.693). Most microarchitectural parameters from CBCT were correlated with those from micro-CT. Some microarchitectural parameters, especially DA, could be used as strong predictors of bone quality in the human jaw. Copyright © 2015 Elsevier Inc. All rights reserved.

A reevaluation of the anatomy of the jaw-closing system in the extant coelacanth Latimeria chalumnae

NASA Astrophysics Data System (ADS)

Dutel, Hugo; Herrel, Anthony; Clément, Gaël; Herbin, Marc

2013-11-01

The coelacanth Latimeria is the only extant representative of the Actinistia, a group of sarcopterygian fishes that originated in the Devonian. Moreover, it is the only extant vertebrate in which the neurocranium is divided into an anterior and a posterior portion that articulate by means of an intracranial joint. This joint is thought to be highly mobile, allowing an elevation of the anterior portion of the skull during prey capture. Here we provide a new description of the skull and jaw-closing system in Latimeria chalumnae in order to better understand its skull mechanics during prey capture. Based on a dissection and the CT scanning of an adult coelacanth, we provide a detailed description of the musculature and ligaments of the jaw system. We show that the m. adductor mandibulae is more complex than previously reported. We demonstrate that the basicranial muscle inserts more anteriorly than has been described previously, which has implications for its function. Moreover, the anterior insertion of the basicranial muscle does not correspond to the posterior tip of the tooth plate covering the parasphenoid, questioning previous inferences made on fossil coelacanths and other sarcopterygian fishes. Strong ligaments connect the anterior and the posterior portions of the skull at the level of the intracranial joint, as well as the notochord and the catazygals. These observations suggest that the intracranial joint is likely to be less mobile than previously thought and that its role during feeding merits to be reexamined.

Legal liability in bisphosphonate-related osteonecrosis of the jaw.

PubMed

Lo Russo, L; Ciavarella, D; Buccelli, C; Di Fede, O; Campisi, G; Lo Muzio, L; Pellegrino, G; Di Lorenzo, P

2014-09-01

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is an adverse reaction that may occur in patients administered with bisphosphonates (BP). This condition can cause high morbidity and hinder quality of life. Its treatment is complex and often unsatisfactory, and prevention strategies may have limited effectiveness, if any. Thus, managing patients treated with BP may result in exposure of the practitioner to legal liability or malpractice claims: legal actions pursuant to BRONJ are reported to be underway on three continents. Nonetheless, the attribution of liability, if any, is a complex process requiring, on the basis of current knowledge, a robust and pragmatic approach to the facts, which must be identified from the point of view of the time, place and individuals involved. This means a comprehensive consideration of the sequence of actions from bisphosphonates prescription to BRONJ occurrence (as well as immediately after, and any action potentially related to its causation or worsening) is required in order to determine if a breach in informing, diagnosing, managing or referring the patient took place, as well as determining if the patient was compliant in attending to prescriptions and follow-up programmes.

Tongue- and Jaw-Specific Contributions to Acoustic Vowel Contrast Changes in the Diphthong /ai/ in Response to Slow, Loud, And Clear Speech

ERIC Educational Resources Information Center

Mefferd, Antje S.

2017-01-01

Purpose: This study sought to determine decoupled tongue and jaw displacement changes and their specific contributions to acoustic vowel contrast changes during slow, loud, and clear speech. Method: Twenty typical talkers repeated "see a kite again" 5 times in 4 speech conditions (typical, slow, loud, clear). Speech kinematics were…

Are mental health problems and depression associated with bruxism in children?

PubMed

Renner, Andréa Coimbra; da Silva, Antônio Augusto Moura; Rodriguez, Juliana Dalla Martha; Simões, Vanda Maria Ferreira; Barbieri, Marco Antonio; Bettiol, Heloísa; Thomaz, Erika Bárbara Abreu Fonseca; Saraiva, Maria da Conceição

2012-06-01

Previous studies have found an association between bruxism and emotional and behavioral problems in children, but reported data are inconsistent. The objective of this study was to estimate the prevalence of bruxism, and of its components clenching and grinding, and its associations with mental problems and depression. Data from two Brazilian birth cohorts were analyzed: one from 869 children in Ribeirão Preto - RP (São Paulo), a more developed city, and the other from 805 children in São Luís - SL (Maranhão). Current bruxism - evaluated by means of a questionnaire applied to the parents/persons responsible for the children - was defined when the habit of tooth clenching during daytime and/or tooth grinding at night still persisted until the time of the assessment. Additionally, the lifetime prevalence of clenching during daytime only and grinding at night only was also evaluated. Mental health problems were investigated using the Strength and Difficulties Questionnaire (SDQ) and depression using the Children's Depression Inventory (CDI). Analyses were carried out for each city: with the SDQ subscales (emotional symptoms, conduct problems, peer problems, attention/hyperactivity disorder), with the total score (sum of the subscales), and with the CDI. These analyses were performed considering different response variables: bruxism, clenching only, and grinding only. The risks were estimated using a Poisson regression model. Statistical inferences were based on 95% confidence intervals (95% CI). There was a high prevalence of current bruxism: 28.7% in RP and 30.0% in SL. The prevalence of clenching was 20.3% in RP and 18.8% in SL, and grinding was found in 35.7% of the children in RP and 39.1% in SL. Multivariable analysis showed a significant association of bruxism with emotional symptoms and total SDQ score in both cities. When analyzed separately, teeth clenching was associated with emotional symptoms, peer problems, and total SDQ score; grinding was

Odontogenic keratocysts in the Basal Cell Nevus (Gorlin-Goltz) Syndrome associated with paresthesia of the lower jaw: Case report, retrospective analysis of a representative Czech cohort and recommendations for the early diagnosis.

PubMed

Hubacek, Milan; Kripnerova, Tereza; Nemcikova, Michaela; Krepelová, Anna; Puchmajerova, Alena; Malikova, Marcela; Havlovicová, Markéta; Cadova, Jana; Kodet, Roman; Macek, Milan; Dostalova, Tatjana

2016-09-01

Identification of early presenting signs of the Basal Cell Nevus (BCNS; synonyme Gorlin-Goltz) syndrome, which is associated with a principal triad of multiple basal cell nevi, jaw odontogenic keratocysts, and skeletal anomalies, in stomatological and neurological practices. Proposal of multidisciplinary diagnostic algorithm comprising other medical specialists, including pathology, imaging, laboratory and molecular analyses based on the study outcomes. Case report of a male patient reporting paresthesia of their lower jaw, with right facial asymmetry (maxilla and mandible) and radiological detection of large osteolytic lesions in both jaws, including a retrospective analysis of a representative Czech cohort with BCNS from within the last decade. Clinical, imaging and laboratory analyses were carried out at a national tertiary centre. A multidisciplinary clinical approach followed by surgical management lead to the identification of odontogenic cysts, which were substantiated by histological examination. DNA sequencing of the PTCH1 gene detected a c.2929dupT resulting in p. Tyr977Leufs*16 pathogenic variant. This finding confirmed the clinical and laboraoty diagnosis of BCNS. Parental DNA analysis showed that this causal genetic defect arose de novo. Surgical management and orthodontic therapy were successful. Analysis of the reported case and retrospective data analysis provided evidence that paresthesia of the lower jaw should be considered as one of the early presenting signs of this rare disorder in stomatological and neurological practice. Obtained results allowed us to formulate recommendations for diagnostic practice in stomatology and neurology.

Teriparatide and the treatment of bisphosphonate-related osteonecrosis of the jaw: a rat model.

PubMed

Ersan, N; van Ruijven, L J; Bronckers, A L J J; Olgaç, V; Ilgüy, D; Everts, V

2014-01-01

The objectives of this study were to establish a bisphosphonate-related osteonecrosis of the jaw (BRONJ) rat model and to analyse the effects of teriparatide (TP) on this model. Sprague-Dawley rats were divided into three groups: I-zoledronic acid (ZA, n = 10); II-ZA and teriparatide (ZA + TP, n = 10); III-control (n = 10). Osteonecrosis was induced by administering zoledronic acid to groups ZA and ZA + TP. A week after the injections, rats underwent extraction of the first left mandibular molar. Following a four week period, TP was administered to the ZA + TP group for 28 days. Upon killing, extraction sockets were examined clinically, radiologically and histopathologically. Clinical examination revealed necrotic bone exposure in none of the animals. MicroCT (µCT) examination showed that bone mineral density of the newly formed bone in the extraction socket was lower in the ZA group than in the ZA + TP group (p < 0.05). Histopathological examination revealed that only the ZA and ZA + TP groups developed osteonecrosis, and the osteonecrotic bone area in the ZA group was larger than that in the ZA + TP group (p < 0.05). Tartrate-resistant acid phosphatase (TRAcP) enzyme histochemistry revealed that the number of detached and large osteoclasts were higher in the ZA group than in other groups, whereas the number of apoptotic osteoclasts in both ZA and ZA + TP groups were higher than in the control group (p < 0.05). Our data indicate that bisphosphonate-related osteonecrosis of the jaw model used in the present study is an attractive model to investigate treatment modalities and that TP might be an effective treatment in BRONJ.

Detachable clamps for minimal access surgery.

PubMed

Frank, T; Willetts, G J; Cuschieri, A

1995-01-01

A detachable clamp and applicator have been developed for use in minimal access surgical operations involving hollow visceral transection and anastomosis. The clamp has parallel jaws which ensure uniform distribution of the occlusive force. Following application on the bowel, the clamp is released from the applicator, thus freeing the access port. On completion of the anastomosis, the clamp is docked to the applicator, its jaws opened for release from the bowel and then closed prior to removal. The jaws of the clamp are kept closed by a pseudoelastic nickel-titanium (NiTi) alloy spring which imparts advantageous force characteristics when compared to stainless steel. The excellent holding and atraumatic characteristics of the detachable clamp have been confirmed by use in laparoscopic and thoracoscopic surgery on the gastrointestinal tract.

Tubing and cable cutting tool

NASA Technical Reports Server (NTRS)

Mcsmith, D. D.; Richardson, J. I. (Inventor)

1984-01-01

A hand held hydraulic cutting tool was developed which is particularly useful in deactivating ejection seats in military aircraft rescue operations. The tool consists primarily of a hydraulic system composed of a fluid reservoir, a pumping piston, and an actuator piston. Mechanical cutting jaws are attached to the actuator piston rod. The hydraulic system is controlled by a pump handle. As the pump handle is operated the actuator piston rod is forced outward and thus the cutting jaws are forced together. The frame of the device is a flexible metal tubing which permits easy positioning of the tool cutting jaws in remote and normally inaccessible locations. Bifurcated cutting edges ensure removal of a section of the tubing or cable to thereby reduce the possibility of accidental reactivation of the tubing or cable being severed.

Bisphosphonate-induced osteonecrosis of the jaws: clinical, imaging, and histopathology findings.

PubMed

Franco-Pretto, Elias; Pacheco, Maikel; Moreno, Andrey; Messa, Oscar; Gnecco, Juan

2014-10-01

To assess the main clinical, radiographic, and histopathologic features of patients with bisphosphonate-induced osteonecrosis of the jaws (BIONJ). Patients with BIONJ diagnosed and treated at the Head and Neck Department, Instituto Nacional de Cancerología, Bogotá, DC, Colombia, between January 2012 and February 2014 were retrospectively included. Patients treated with sequestrectomy or curettage were excluded. Specimens from selected patients were reexamined under a light microscope. Clinical and imaging findings and sociodemographic variables were also reviewed. Five stage 3 BIONJ cases were included. Imaging found massive osteolysis. Histopathology found devitalized trabecular bone, an absence of osteoblastic rimming, osteoclastic necrosis, and viable periosteum. Actinomyces spp colonies were limited to superficial layers. BIONJ histopathology is different from that of other necrotizing and inflammatory bone diseases. This relates to the known antiresorptive mechanism of bisphosphonates, which is the basis of their therapeutic action. Nevertheless, further study with larger series should be accomplished. Copyright © 2014 Elsevier Inc. All rights reserved.

The Jaw Adductor Muscle Complex in Teleostean Fishes: Evolution, Homologies and Revised Nomenclature (Osteichthyes: Actinopterygii)

PubMed Central

Datovo, Aléssio; Vari, Richard P.

2013-01-01

The infraclass Teleostei is a highly diversified group of bony fishes that encompasses 96% of all species of living fishes and almost half of extant vertebrates. Evolution of various morphological complexes in teleosts, particularly those involving soft anatomy, remains poorly understood. Notable among these problematic complexes is the adductor mandibulae, the muscle that provides the primary force for jaw adduction and mouth closure and whose architecture varies from a simple arrangement of two segments to an intricate complex of up to ten discrete subdivisions. The present study analyzed multiple morphological attributes of the adductor mandibulae in representatives of 53 of the 55 extant teleostean orders, as well as significant information from the literature in order to elucidate the homologies of the main subdivisions of this muscle. The traditional alphanumeric terminology applied to the four main divisions of the adductor mandibulae – A1, A2, A3, and Aω – patently fails to reflect homologous components of that muscle across the expanse of the Teleostei. Some features traditionally used as landmarks for identification of some divisions of the adductor mandibulae proved highly variable across the Teleostei; notably the insertion on the maxilla and the position of muscle components relative to the path of the ramus mandibularis trigeminus nerve. The evolutionary model of gain and loss of sections of the adductor mandibulae most commonly adopted under the alphanumeric system additionally proved ontogenetically incongruent and less parsimonious than a model of subdivision and coalescence of facial muscle sections. Results of the analysis demonstrate the impossibility of adapting the alphanumeric terminology so as to reflect homologous entities across the spectrum of teleosts. A new nomenclatural scheme is proposed in order to achieve congruence between homology and nomenclature of the adductor mandibulae components across the entire Teleostei. PMID

Microscopic Evaluation of the Effect of Oral Microbiota on the Development of Bisphosphonate-Related Osteonecrosis of the Jaws in Rats

PubMed Central

Silveira, Felipe M.; Etges, Adriana; Correa, Marcos B.

2016-01-01

ABSTRACT Objectives Osteonecrosis of the jaws is a side effect associated with the use of bisphosphonates. Using histologic analysis, this study aimed to evaluate the influence of microbial colonies in the development of osteonecrosis in the jaws of rats subjected to nitrogenous and non-nitrogenous bisphosphonates, undergoing surgical procedures. Material and Methods Thirty-four rats (Rattus norvegicus, Wistar strain) were allocated randomly into three groups: 12 animals treated with zoledronic acid; 12 animals treated with clodronate; and 10 animals treated with saline. Sixty days after the start of treatment, the animals underwent three extractions of the upper right molars. After 120 days of drug administration, the rats were killed. Histologic analysis was performed on specimens stained with hematoxylin and eosin by the technique of manual counting points using Image-Pro Plus software on images of the right hemimaxilla. Results Osteonecrosis was induced in the test groups. There was no statistically significant association between the presence of microbial colonies and the presence of non-vital bone (Kruskal-Wallis, P > 0.05). Conclusions Use of zoledronic acid was associated with non-vital bone and the results suggested that the presence of microbial colonies does not lead to osteonecrosis. PMID:28154747

Neuronal activity related to spontaneous and capsaicin-induced rhythmical jaw movements in the rat.

PubMed

Ohta, M; Sasamoto, K; Kobayashi, J

1998-02-01

Intraoral capsaicin induced rhythmical jaw movements (RJM) in anesthetized rats. Neurons in the trigeminal spinal nucleus caudalis or the cortico-peduncular (CP) axons were extracellularly recorded. Capsaicin excited dose-dependently most caudalis neurons, which were activated by stimulation of the oral cavity and/or the tooth pulp and activated during spontaneous or induced RJM. Ten of 55 CP axons were antidromically activated by stimulation of the contralateral trigeminal motor nucleus. All antidromic and 29 other CP axons discharged prior to the spontaneous RJM, but most of them did not during capsaicin-induced RJM. These neuronal activities possibly initiate spontaneous RJM although the activities of caudalis neurons are necessary for capsicin-induced RJM.

Cerebro-Oculo-Facio-Skeletal Syndrome (COFS)

MedlinePlus

... clenched fists, wide-set nipples, vision impairments, involuntary eye movements, and impaired cognitive development, which can be moderate ... clenched fists, wide-set nipples, vision impairments, involuntary eye movements, and impaired cognitive development, which can be moderate ...

Influence of cladogenesis on feeding structures in drums (Teleostei: Sciaenidae).

PubMed

Deary, Alison L; Hilton, Eric J

2017-02-01

Drums (family Sciaenidae) are common in tropical to temperate coastal and estuarine habitats worldwide and present a broad spectrum of morphological diversity. The anatomical variation in this family is particularly evident in their feeding apparatus, which may reflect the partitioning of adult foraging habitats. Adult and early life history stage sciaenids may display ecomorphological patterns in oral and pharyngeal jaw elements but because sciaenids are hierarchically related, the morphological variation of the feeding apparatus cannot be analyzed as independent data. Morphological patterns have been identified in three sciaenid genera from the Chesapeake Bay but it is not known if these patterns are present in other genera of the family and if such patterns are constrained by phylogenetic history. In this study, phylogenetic comparative methods were applied to two sets of oral jaw data obtained from growth series of 11 species of cleared and double-stained Chesapeake Bay sciaenids and alcohol-preserved museum specimens representing 65 of the 66 recognized genera to determine the magnitude of phylogenetic dependence present in the structure of the oral jaws using a recent molecular phylogeny of the family. Pagel's lambda, a measure of phylogenetic signal, was low for pelagic sciaenids in premaxilla, lower jaw, and ascending process lengths, indicating influence of selective forces on the condition of these traits. Conversely, for benthic sciaenids, phylogenetic signal was high for lower jaw and ascending process lengths, indicating significant phylogenetic constraint for their condition in these taxa. Pagel's lambda was intermediate for premaxilla length in benthic sciaenids, suggesting that the length of the premaxilla is influenced by a mix of selective forces and phylogenetic constraint. Although the ecomorphological patterns identified in the oral jaws of scaienids are not entirely free of phylogenetic dependence, selective forces related to foraging are

Expression of forkhead box transcription factor genes Foxp1 and Foxp2 during jaw development.

PubMed

Cesario, Jeffry M; Almaidhan, Asma A; Jeong, Juhee

2016-03-01

Development of the face is regulated by a large number of genes that are expressed in temporally and spatially specific patterns. While significant progress has been made on characterizing the genes that operate in the oral region of the face, those regulating development of the aboral (lateral) region remain largely unknown. Recently, we discovered that transcription factors LIM homeobox (LHX) 6 and LHX8, which are key regulators of oral development, repressed the expression of the genes encoding forkhead box transcription factors, Foxp1 and Foxp2, in the oral region. To gain insights into the potential role of the Foxp genes in region-specific development of the face, we examined their expression patterns in the first pharyngeal arch (primordium for the jaw) of mouse embryos at a high spatial and temporal resolution. Foxp1 and Foxp2 were preferentially expressed in the aboral and posterior parts of the first pharyngeal arch, including the developing temporomandibular joint. Through double immunofluorescence and double fluorescent RNA in situ hybridization, we found that Foxp1 was expressed in the progenitor cells for the muscle, bone, and connective tissue. Foxp2 was expressed in subsets of bone and connective tissue progenitors but not in the myoblasts. Neither gene was expressed in the dental mesenchyme nor in the oral half of the palatal shelf undergoing extensive growth and morphogenesis. Together, we demonstrated for the first time that Foxp1 and Foxp2 are expressed during craniofacial development. Our data suggest that the Foxp genes may regulate development of the aboral and posterior regions of the jaw. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of dexamethasone and nimesulide on bisphosphonate-related osteonecrosis of the jaw: An experimental study.

PubMed

Oliveira, Camila Carvalho de; Barros Silva, Paulo Goberlânio de; Ferreira, Antonio Ernando Carlos; Gonçalves, Romélia Pinheiro; Sousa, Fabrício Bitu de; Mota, Mário Rogério Lima; Alves, Ana Paula Negreiros Nunes

2017-11-01

To evaluate the effects of dexamethasone (DEX) and nimesulide (NIM) on Bisphosphonate-related Osteonecrosis of the Jaw (BRONJ) in rats. BRONJ was induced by zoledronic acid (ZA) infusion (0.2mg/kg) in Wistar rats (n=8), followed by extraction of the left lower first molar (BRONJ groups). Control groups (n=40) received saline (IV). For eight weeks, DEX (0.04, 0.4, 4mg/kg) or saline (SAL) were administered by gavage 24h before each infusion of ZA or saline (IV), or NIM (10.3mg/kg) was administered 24h and 12h before each infusion of ZA or saline (IV). The haematological analyses were conducted weekly. After euthanasia (day 70), the jaws were submitted to radiographic and microscopic analysis. Kidney, liver, spleen and stomach were analysed histopathologically. The BRONJ groups showed a higher radiolucent area compared with the control groups (p<0.05). Histomorphometric analysis revealed healing and new bone formation in the control groups, while the BRONJ groups exhibited devitalized bone with bacterial colonies and inflammatory infiltrate. The BRONJ-DEX 0.4 and 4mg/kg groups had a greater number of bacterial colonies (p<0.05) and an increased polymorphonuclear cell count compared to the saline-BRONJ group, while the BRONJ-NIM group had a lower polymorphonuclear count (p<0.05). The BRONJ groups had leucocytosis, which was reduced by DEX administration. Treatments with DEX with or without ZA caused white pulp atrophy. Thus, DEX or NIM therapy was not effective in preventing radiographic and histopathologic events associated with BRONJ. Treatment with DEX attenuated leucocytosis post-infusion with ZA. Copyright © 2017 Elsevier Ltd. All rights reserved.

Prevalence and clinical characteristics of tori and jaw exostoses in a teaching hospital in Jordan.

PubMed

Sawair, Faleh A; Shayyab, Mohammad H; Al-Rababah, Mohammad A; Saku, Takashi

2009-12-01

To determine the prevalence and clinical characteristics of oral bony outgrowths (OBOs); torus palatinus (TP), torus mandibularis (TM), and exostoses in Jordanian dental patients. This cross-sectional study was conducted between November 1 and December 31, 2008 at the University of Jordan Hospital, Amman, Jordan. Clinical examinations of 618 patients (354 men and 264 women), 10-82 years of age, were conducted to determine the presence of OBOs. There were 239 subjects (38.7%) who had OBOs. Nearly one-third (34.6%) had TP, TM, or both. The prevalence rates were 25.7% for TM, 15.4% for TP, and 14.4% for exostoses. The OBOs were mostly noted in patients in their fifth decade of life, with attrition, clenching, or bruxism. Women had more TP, but gender differences were not statistically significant in cases of TM and exostoses. Most TP were large in size (71.6%), spindle (41.1%), or flat (40%) in shape, and located at the premolar-molar region (45.3%). The TM were mostly medium to large in size (84.9%), bilateral (81.1%), composed of single node (69.2%), and located at the premolar region (65.4%). Of the studied subjects, 7.1% had mandibular buccal exostosis, 10% had maxillary buccal, and 2.4% had palatal exostoses. Statistically significant associations were noticed between the concurrent existence of OBOs. A relatively high prevalence of OBOs was noted, and this should be taken into consideration when planning periodontal surgery and prosthodontic treatment.

Spatiotemporal movement variability in ALS: Speaking rate effects on tongue, lower lip, and jaw motor control

PubMed Central

Kuruvilla-Dugdale, Mili; Mefferd, Antje

2017-01-01

Purpose Although it is frequently presumed that bulbar muscle degeneration in Amyotrophic Lateral Sclerosis (ALS) is associated with progressive loss of speech motor control, empirical evidence is limited. Furthermore, because speaking rate slows with disease progression and rate manipulations are used to improve intelligibility in ALS, this study sought to (i) determine between and within-group differences in articulatory motor control as a result of speaking rate changes and (ii) identify the strength of association between articulatory motor control and speech impairment severity. Method Ten talkers with ALS and 11 healthy controls repeated the target sentence at habitual, fast, and slow rates. The spatiotemporal variability index (STI) was calculated to determine tongue, lower lip, and jaw movement variability. Results During habitual speech, talkers with mild-moderate dysarthria displayed significantly lower tongue and lip movement variability whereas those with severe dysarthria showed greater variability compared to controls. Within-group rate effects were significant only for talkers with ALS. Specifically, lip and tongue movement variability significantly increased during slow speech relative to habitual and fast speech. Finally, preliminary associations between speech impairment severity and movement variability were moderate to strong in talkers with ALS. Conclusion Between-group differences for habitual speech and within-group effects for slow speech replicated previous findings for lower lip and jaw movements. Preliminary findings of moderate to strong associations between speech impairment severity and STI suggest that articulatory variability may vary from pathologically low (possibly indicating articulatory compensation) to pathologically high variability (possibly indicating loss of control) with dysarthria progression in ALS. PMID:28528293

An early role for sonic hedgehog from foregut endoderm in jaw development: ensuring neural crest cell survival.

PubMed

Brito, José M; Teillet, Marie-Aimée; Le Douarin, Nicole M

2006-08-01

We have investigated the role of Sonic hedgehog (Shh) in the development of facial structures by depriving chicken embryos of the most anterior sources of this morphogen, including the prechordal plate and the anterior ventral endoderm of the foregut, before the onset of neural crest cell (NCC) migration to the first branchial arch (BA1). The entire forehead, including the foregut endoderm, was removed at 5- to 10-somite stage (ss), which led to the absence of the lower jaw when the operation was performed before 7-ss. If the embryos were deprived of their forehead at 8- to 10-ss, they were later on endowed with a lower beak. In embryos that were operated on early, the NCCs migrated normally to BA1 but were subjected to massive apoptosis a few hours later. Cell death did not occur when forehead excision was performed at a later stage. In this case, onward expression of Shh in the ventral foregut endoderm extended caudally over the excision limit, and we hypothesized that absence of Shh production by the endoderm in embryos that were operated on early could be responsible for the NCC apoptosis and the failure of BA1 development. We thus provided exogenous Shh to the embryos that were operated on before 7-ss. In this case, the development of the lower jaw was rescued. Therefore, Shh derived from the ventral foregut endoderm ensures the survival of NCCs at a critical stage of BA1 development.

[Comparison of jaw thrust and trapezius squeezing test as indicators for laryngeal mask airway insertion in infants and young children].

PubMed

Liu, J Z; Zhao, J; Zhang, Y J

2016-02-01

To compare the effectiveness of the jaw thrust and the trapezius squeezing test(TST) for laryngeal mask airway (LMA) insertion in infants and children under sevoflurane anesthesia. A total of 100 children aged from 6 month to 3 years, American Society of Anesthesiologists(ASA) Ⅰ-Ⅱ and undergoing minor operation were enrolled from January to June 2015 in Tianjin Children's Hospital. The patients were randomly divided into jaw thrusting group (Group J, n=50)and trapezius squeezing group(Group T, n=50). Anesthesia was induced with sevoflurane. When children's eyelash reflex lose, jaw thrust/trapezius squeeze was applied every 15 seconds.It's considered that the depth of anesthesia was not enough, and test reaction was positive if any movements of body, limbs or toes were found at the point of test. Sevoflurane should be keep on inhalation until negative test reaction was appeared. Then LMA was inserted immediately.The time required for the negative test, end-tidal sevoflurane concentrations (ETsev), the index of Narcotrend anesthesia monitor(NT), the occurrence of gross purposeful movements, coughing, gagging, breath-holding, laryngospasm or an SpO2 < 90% during LMA insertion in two groups of patients were observed and recorded. The condition of LMA insertion and the rate of successful insertion were evaluated. The blood pressure(BP), heart rate(HR) and SpO2 were also recorded before and after LMA insertion. In group J and group T, the time required for the negative test was (2.31±1.03) vs (2.85±0.97)min(t=-2.462, P<0.05), ETsev was(3.25±1.02)% vs (3.81±0.87) %(t=-2.361, P<0.05), the depth of anesthesia NT index was(50.41±5.38) vs (41.32±4.92)(t=3.021, all P<0.05). All of above results were significantly different. The successful rate of the first attempt LMA insertion was 78% vs 100%(χ(2)=12.36 , P<0.01), respectively. The differences had statistical significance. The conditions of LMA insertion in group T were superior to those in group J. The incidences

The evolution of pharyngognathy: a phylogenetic and functional appraisal of the pharyngeal jaw key innovation in labroid fishes and beyond.

PubMed

Wainwright, Peter C; Smith, W Leo; Price, Samantha A; Tang, Kevin L; Sparks, John S; Ferry, Lara A; Kuhn, Kristen L; Eytan, Ron I; Near, Thomas J

2012-12-01

The perciform group Labroidei includes approximately 2600 species and comprises some of the most diverse and successful lineages of teleost fishes. Composed of four major clades, Cichlidae, Labridae (wrasses, parrotfishes, and weed whitings), Pomacentridae (damselfishes), and Embiotocidae (surfperches); labroids have been an icon for studies of biodiversity, adaptive radiation, and sexual selection. The success and diversification of labroids have been largely attributed to the presence of a major innovation in the pharyngeal jaw apparatus, pharyngognathy, which is hypothesized to increase feeding capacity and versatility. We present results of large-scale phylogenetic analyses and a survey of pharyngeal jaw functional morphology that allow us to examine the evolution of pharyngognathy in a historical context. Phylogenetic analyses were based on a sample of 188 acanthomorph (spiny-rayed fish) species, primarily percomorphs (perch-like fishes), and DNA sequence data collected from 10 nuclear loci that have been previously used to resolve higher level ray-finned fish relationships. Phylogenies inferred from this dataset using maximum likelihood, Bayesian, and species tree analyses indicate polyphyly of the traditional Labroidei and clearly separate Labridae from the remainder of the traditional labroid lineages (Cichlidae, Embiotocidae, and Pomacentridae). These three "chromide" families grouped within a newly discovered clade of 40 families and more than 4800 species (>27% of percomorphs and >16% of all ray-finned fishes), which we name Ovalentaria for its characteristic demersal, adhesive eggs with chorionic filaments. This fantastically diverse clade includes some of the most species-rich lineages of marine and freshwater fishes, including all representatives of the Cichlidae, Embiotocidae, Pomacentridae, Ambassidae, Gobiesocidae, Grammatidae, Mugilidae, Opistognathidae, Pholidichthyidae, Plesiopidae (including Notograptus), Polycentridae, Pseudochromidae

Laser beam guard clamps

DOEpatents

Dickson, Richard K.

2010-09-07

A quick insert and release laser beam guard panel clamping apparatus having a base plate mountable on an optical table, a first jaw affixed to the base plate, and a spring-loaded second jaw slidably carried by the base plate to exert a clamping force. The first and second jaws each having a face acutely angled relative to the other face to form a V-shaped, open channel mouth, which enables wedge-action jaw separation by and subsequent clamping of a laser beam guard panel inserted through the open channel mouth. Preferably, the clamping apparatus also includes a support structure having an open slot aperture which is positioned over and parallel with the open channel mouth.

Jaw muscle development as evidence for embryonic repatterning in direct-developing frogs.

PubMed Central

Hanken, J; Klymkowsky, M W; Alley, K E; Jennings, D H