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1

Estimating the color of maxillary central incisors based on age and gender  

PubMed Central

Statement of problem There is no scientific information regarding the selection of the color of teeth for edentulous patients. Purpose The purpose of this study was to evaluate linear regression models that may be used to predict color parameters for central incisors of edentulous patients based on some characteristics of dentate subjects. Material and methods A spectroradiometer and an external light source were set in a noncontacting 45/0 degree (45-degree illumination and 0-degree observer) optical configuration to measure the color of subjects’ vital craniofacial structures (maxillary central incisor, attached gingiva, and facial skin). The subjects (n=120) were stratified into 5 age groups with 4 racial groups and balanced for gender. Linear first-order regression was used to determine the significant factors (?=.05) in the prediction model for each color direction of the color of the maxillary central incisor. Age, gender, and color of the other craniofacial structures were studied as potential predictors. Final predictions in each color direction were based only on the statistically significant factors, and then the color differences between observed and predicted CIELAB values for the central incisors were calculated and summarized. Results The statistically significant predictors of age and gender accounted for 36% of the total variability in L*. The statistically significant predictor of age accounted for 16% of the total variability in a*. The statistically significant predictors of age and gender accounted for 21% of the variability in b*. The mean ?E (SD) between predicted and observed CIELAB values for the central incisor was 5.8 (3.2). Conclusions Age and gender were found to be statistically significant determinants in predicting the natural color of central incisors. Although the precision of these predictions was less than the median color difference found for all pairs of teeth studied, and may be considered an acceptable precision, further study is needed to reduce this precision to the limit of detection. Clinical Implications Age is highly correlated with the natural color of the central incisors. When age increases, the central incisor becomes darker, more reddish, and more yellow. Also, the women subjects in this study had lighter and less yellow central incisors than the men.

Gozalo-Diaz, David; Johnston, William M.; Wee, Alvin G.

2008-01-01

2

A case of impacted maxillary central incisor and its management  

PubMed Central

Impaction of maxillary permanent central incisor is not a frequently reported case in dental practice, but its treatment is challenging because of its importance to facial esthetics. Early detection of such teeth is most important if complications are to be avoided. We report a case of a 14-year-old female with an impacted central incisor tooth in the maxillary anterior region. The impacted supernumerary tooth which was preventing the eruption of permanent incisor was surgically removed. Combined approach with surgical exposure and the application of an orthodontic force brought the impacted left maxillary central incisor down to its proper position in the dental arch.

Kannan, Prem Kumar Karupanna Pillai Subbiah; Palanisamy, Senthil Kumar Kullam Palayam; Kumar, Tamizharasi Senthil

2012-01-01

3

Solitary median maxillary central incisor (SMMCI) syndrome  

PubMed Central

Solitary median maxillary central incisor syndrome (SMMCI) is a complex disorder consisting of multiple, mainly midline defects of development resulting from unknown factor(s) operating in utero about the 35th–38th day(s) from conception. It is estimated to occur in 1:50,000 live births. Aetiology is uncertain. Missense mutation in the SHH gene (I111F) at 7q36 may be associated with SMMCI. The SMMCI tooth differs from the normal central incisor, in that the crown form is symmetric; it develops and erupts precisely in the midline of the maxillary dental arch in both primary and permanent dentitions. Congenital nasal malformation (choanal atresia, midnasal stenosis or congenital pyriform aperture stenosis) is positively associated with SMMCI. The presence of an SMMCI tooth can predict associated anomalies and in particular the serious anomaly holoprosencephaly. Common congenital anomalies associated with SMMCI are: severe to mild intellectual disability, congenital heart disease, cleft lip and/or palate and less frequently, microcephaly, hypopituitarism, hypotelorism, convergent strabismus, oesophageal and duodenal atresia, cervical hemivertebrae, cervical dermoid, hypothyroidism, scoliosis, absent kidney, micropenis and ambiguous genitalia. Short stature is present in half the children. Diagnosis should be made by eight months of age, but can be made at birth and even prenatally at 18–22 weeks from the routine mid-trimester ultrasound scan. Management depends upon the individual anomalies present. Choanal stenosis requires emergency surgical treatment. Short stature may require growth hormone therapy. SMMCI tooth itself is mainly an aesthetic problem, which is ideally managed by combined orthodontic, prosthodontic and oral surgical treatment; alternatively, it can be left untreated.

Hall, Roger K

2006-01-01

4

Fused upper central incisors: management of two clinical cases  

PubMed Central

Summary This paper reports the management of two clinical cases, in which the upper right central incisor was fused with a supernumerary tooth and the upper left central incisor was macrodontic. A radiographic examination revealed that the fused teeth had two separate roots. Hemisectioning of the fused teeth was performed, the supernumerary portion was extracted and the remaining part was reshaped to remove any sharp margins and to achieve a normal morphology. The macrodontic central incisors were not treated. At 12-months post-surgery there were no periodontal problems and no hypersensitivity. Orthodontic treatment was performed to appropriately align the maxillary teeth and to correct the malocclusion.

Sfasciotti, Gian Luca; Marini, Roberta; Bossu, Maurizio; Ierardo, Gaetano; Annibali, Susanna

2012-01-01

5

Orthodontically induced eruption of a horizontally impacted maxillary central incisor.  

PubMed

This case report presents the clinical features and periodontal findings in a patient with a horizontally impacted maxillary central incisor that had been exposed and aligned after a closed-eruption surgical technique. By combining 3 treatment stages-maxillary expansion, crown exposure surgery, and induced eruption-the horizontally impacted incisor was successfully moved into proper position. The patient finished treatment with a normal and stable occlusion between the maxillary and mandibular arches, and an adequate width of attached gingiva, even in the area surrounding the crown. The 5-year follow-up of stability and periodontal health demonstrated esthetic and functional outcomes after orthodontically induced tooth eruption. Clinical evaluation showed that the treated central incisor had periodontal clinical variables related to visible plaque, bleeding on probing, width of attached gingiva, and crown length that resembled the contralateral incisor. PMID:23810053

Rizzatto, Susana Maria Deon; de Menezes, Luciane Macedo; Allgayer, Susiane; Batista, Eraldo Luiz; Freitas, Maria Perpétua Mota; Loro, Raphael Carlos Drumond

2013-07-01

6

Surgical repositioning of the impacted immature maxillary central incisor.  

PubMed

Surgical repositioning is a treatment option for an impacted tooth with root dilaceration in an inverted position. In this case report, surgical repositioning of an abnormally impacted and labially dilacerated maxillary right central incisor is described. The impacted and dilacerated maxillary incisor was surgically repositioned in the early root development period and erupted into proper position with normal root development during a 2-year follow-up period. PMID:21206930

Choi, Sung Chul; Park, Jae Hong; Kwon, Yong-Dae; Yoo, Eun Kyu; Yoo, Jung Eun

2011-01-01

7

Age determination from central incisors of fetuses and infants.  

PubMed

Age at time of death for a fetus or infant is an important issue in the field of forensic science. Dental development can give an accurate measure of infant and fetal age and current literature does not include any studies of dental age from central incisor development. The objective of this study is to determine the age of deceased fetuses and infants by examining metric tooth development of central incisors in deceased fetuses and infants. Five dimensions of 76 maxillary and mandibular central incisors were measured: mesio-distal (MD), bucco-lingual (BL), crown height (CH), crown thickness (CT), and root height (RH). The results showed that 44.45+/-0-2 weeks is a sectional time for age calculations, which corresponds to 40 weeks from conception plus 4 to 5 weeks after birth. Four ATA entitled age formulas are derived to give the relation of age with tooth dimensions before and after 44.45 weeks [ATA is the special name given to the honor of the great Turkish leader Mustafa Kemal Atatürk (1881-1938)]. Age estimation can be calculated from these formulas with an accuracy of the age +/-0-2 weeks. Also, calcification time can be determined from ATA formulas. In conclusion, the age of fetuses and infants can be assessed by the measurements of a single central incisor. According to this research, when estimating age during identification studies, forensic researchers must take into consideration the period of embryonic human growth and development. PMID:19117707

Aka, P Sema; Canturk, Nergis; Dagalp, Rukiye; Yagan, Murat

2009-01-30

8

[A solitary central maxillary incisor and holoprosencephaly in siblings].  

PubMed

In families in which holoprosencephaly seems to be inherited by a rare dominant autosomal mutation, some individuals exhibit a single central maxillary incisor (SCMI). This anomaly was considered a minimal manifestation of the gene for holoprosencephaly. We report on a family, in which one child suffered from median cleft lip and palate and alobar holoprosencephaly, whereas the other child only had a SCMI. In the father and his sister lateral upper incisors were absent. Therefore the question is raised as to whether this anomaly may be related to the same condition. PMID:2135272

Süss, J; Pfeiffer, R A; Zschiesche, S; König, R

1990-12-01

9

[Esthetic IMZ implant for a central incisor].  

PubMed

Replacement of a missing incisor with an osseo-integrated implant, presents a difficult prosthetic problem for the practitioner because of the obliqueness of the implant and its diameter smaller than the tooth to be reconstructed. Therefore, a topographic and aesthetic pre-estimation is highly desirable. The patient whose treatment is described hereafter, presents large diastemas permitting to set the missing tooth in several locations. The various options are simulated on a study model and recorded by a silicone or resin index. This index is cut out so that the implant site is clearly defined and it presents a guide rod indicating the direction of the alveolar bone. The optimal site is selected during the surgical procedure with the most favorable index depending on the residual bone. After the implant is released, the location impression, is taken using asymmetric transfer allowing a strict positioning of the implant's replica and its thread. In order to prevent the making of a triangular-shaped crown, a false transfixed core removable is built over the intramobile component of the IMZ as well as pa periodontal ring. The latter is independent and maintained by the intramobile component. It compensates the difference in diameter between the implant and the natural tooth to be reconstructed. Its finely polished but asymmetric internal aspect prevents the rotation of the device. The volume of this device is controlled by a silicone index made on the preestimation model. Both pieces are cast in gold and assembled on the implant with a positioning indes. Parallel proximal grooves increase the friction of the core and a ceramo-metal crown is built in the conventional fashion. It is temporally cemented, and periodically removed and cleansed. The absence of gingical sulcus provides an aesthetic result similar to a bridge component. PMID:2638613

Brabant, A; Lejuste, P; Andriessens, J

1989-12-01

10

The Aesthetic Management of a 180 Degree Rotated Maxillary Central Incisor With Two Root Canals- A Case Report  

PubMed Central

The success of the root canal treatment is based on a thorough knowledge of the normal tooth, the root and the root canal morphology, which include variations. Tooth rotation is a common finding in the premolar-molar region, but a 180 degree rotation of the maxillary central incisor is extremely rare and it has not documented anywhere in the dental literature. This case report describes the aesthetic correction of a maxillary central incisor with a 180 degree rotation and two root canals.

Jain, Shweta; Narang, Praful; Sharma, Rohit; Agarwal, Vijay

2013-01-01

11

Treatment of cariously involved fused maxillary primary lateral and central incisors  

Microsoft Academic Search

A 3-and-a-half-year-old male child presented with fused cariously involved right maxillary primary central and lateral incisors as well as a previously traumatized non-vital left primary central incisor with a draining fistula. The child also had other restorative needs and the decision taken was to address all needs under a G.A. With respect to the fused incisors, these were split and

Hossam E. ElBadrawy

2001-01-01

12

Traumatic loss of a maxillary central incisor treated with nonextraction orthodontics.  

PubMed

This case report describes the orthodontic treatment of a girl who lost her maxillary left central incisor from trauma. The patient had a concave profile, a Class I molar relationship on the right side and a Class II molar relationship on the left side, with a slight maxillary retrusion, an anterior edge-to-edge bite, and a posterior crossbite. Therefore, the treatment consisted of rapid palatal expansion to widen the maxilla in a transverse direction along with reverse headgear to improve the incisor relationship. The crown of the left canine was modified to resemble the left lateral incisor, and a porcelain veneer was placed to make the left lateral incisor resemble the left central incisor. This case report illustrates how orthodontics alone can be used to treat a missing central incisor, without a bridge or an implant. PMID:23374932

Huang, Shiyou; Kang, Ting; Duan, Yinzhong

2013-02-01

13

Inner canthal distance and geometric progression as a predictor of maxillary central incisor width  

Microsoft Academic Search

Statement of Problem. Estimating the mesiodistal width of maxillary central incisors may be difficult when artificial teeth are selected for edentulous subjects. Purpose. This study examined the relationship between inner canthal distance and maxillary central incisor mesiodistal width in terms of the geometric progression popularly known as the golden proportion. Material and Methods. Two hundred twenty-nine dentate Saudi subjects (120

Mohammed Aleem Abdullah

2002-01-01

14

Endodontic Management of a Mandibular Central Incisor with Type IV Canal Pattern: A Case Report  

PubMed Central

The success of endodontic treatment requires the knowledge of tooth morphology and its variations. Mandibular incisor’s anatomy presents a challenge when an endodontic access is made, because of its small size and high prevalence of two canals. We are describing a Weine’s Type IV root canal configuration that was detected in a mandibular central incisor, which was demonstrated by a radiographic examination. This article also focuses on the successful endodontic treatment of a mandibular central incisor with a single canal at the pulp chamber, which divided into two distinct and separate canals (buccolingual) at the middle third of the root.

Mittal, Sunandan; Kumar, Tarun; Sharma, Jyotika; Mittal, Shifali; Ahuja, Tarun

2014-01-01

15

Conservative restoration of a traumatically involved central incisor.  

PubMed

The use of a direct composite material known for excellent polishability, polish retention, and wear resistance is described in this case of a fractured central incisor restoration. The method used enabled the clinician to conserve tooth structure and maintain full control of the outcome while creating an esthetically imperceptible, reliable, and durable restoration for a young male patient. Emphasized in this case are the techniques of layering, contouring, and polishing of a nanocomposite used to maximize esthetics and meet patient expectations. To further ensure imperceptibility, the author recommends first facilitating color shade selection for both body and dentin-especially in two-shade or multiple-shade restorations-by placing the composite in its planned area of the restoration and curing it in its proper thickness to allow a preview and recipe map. PMID:22536659

Bassett, Joyce

2012-04-01

16

Re - treatment of a Two-rooted Maxillary Central Incisor - A Case Report  

PubMed Central

This case report is on endodontic retreatment of a maxillary central incisor with two roots. A twenty-year-old male patient presented with pain in maxillary left central incisor. Radiographic examination showed an incompletely filled canal and an additional palatal root with periapical radiolucent lesion. Conventional cleaning and shaping of both the roots, i.e., buccal and additional palatal root canals was performed and obturation was done. After one year recall examination, the tooth was asymptomatic and periapical lesion had healed.

Garlapati, Roopadevi; Venigalla, Bhuvan Shome; Chintamani, Rammohan; Thumu, Jayaprakash

2014-01-01

17

Movement of an upper central incisor across the midline in a patient with cleft of primary palate.  

PubMed

Orthodontic treatment for a 10-years-old girl, with repaired bilateral cleft lip and left incomplete unilateral alveolar cleft, was performed by moving her right maxillary central incisor across the midline to replace her congenital missing central incisor and then moving the right lateral incisor toward the midline to act as a new central incisor. A malformed supernumerary tooth, positioned between the right central and lateral incisor, was extracted during incisor movement. Significant lip profile improvement was accomplished by maxillary and mandibular anterior teeth retraction into three-premolar extraction spaces. Not only natural functional occlusion, deviated midpalatal suture along the central incisor, and no obvious root resorption were obtained but also narrowing the alveolar bone cleft which was beneficial for bone continuity supporting dental structures, satisfactory results were possible for the patient with primary palate cleft. PMID:24386757

Manosudprasit, Montian; Wangsrimongkol, Tasanee; Pisek, Poonsak; Chittiwatanapong, Nisa

2013-09-01

18

Direct composite restorations in anterior teeth. Managing symmetry in central incisors.  

PubMed

In direct restorations of anterior teeth, particularly central incisors, symmetry plays an important role. The clinician can take advantage of silicone indexes based on a wax-up to build palatal and incisal walls; however, when he has to reproduce free-hand chair-side symmetrical items like interproximal emergence profiles, macro- and microsurface textures, and chromatic characteristics, the result can often be unpredictable. A step-by-step class IV restoration treatment will be described, as well as a simple procedure to help reproduce, check and correct symmetrically interproximal wall contours and chromatic characteristics. PMID:24757696

Paolone, Gaetano

2014-01-01

19

Innovative biomechanics for orthodontic correction of torsiversion of maxillary central incisor caused by twin mesiodens  

PubMed Central

Mesiodens is the most common type of supernumerary teeth found in the premaxilla between the two central incisors. Early and proper diagnosis and appropriate treatment plan is critical in eluding the extent of treatment needed. This case report presents the successful orthodontic and esthetic management of an unusual case of Indian origin with twin mesiodens in the maxillary arch causing torsiversion and attrition of mandibular incisors due to occlusal trauma.

Monga, Nitika; Kharbanda, Om Prakash; Duggal, Ritu

2014-01-01

20

Bilateral presence of two root canals in maxillary central incisors: A rare case study  

PubMed Central

Success in root canal treatment is achieved after thorough cleaning and shaping followed by complete obturation of the canal system. Therefore, endodontic therapy requires specific and complete knowledge of the internal and external dental anatomy, and its variations in presentation. The internal anatomy of the maxillary central incisor is well-known and usually presents one root canal system. This case report describes an endodontic treatment of traumatized both maxillary central incisors with two canal systems. Knowledge of dental anatomy is fundamental for proper endodontic practice. When root canal treatment is performed, the clinician should be aware that both external and internal anatomy may be abnormal.

Kavitha, M.; Gokul, Kannan; Ramaprabha, B.; Lakshmi, Amudha

2014-01-01

21

Single maxillary central incisor in association with mid-line anomalies.  

PubMed

A single maxillary central incisor may occur as an isolated dental finding. However, it has also been reported to occur in association with autosomal dominant holoprosencephaly, in association with growth retardation with or without growth hormone deficiency and occasionally in association with other mid-line developmental defects. Holoprosencephaly and pituitary dysfunction are two specific examples of mid-line defects and this report emphasises that other mid-line defects may be associated with a single maxillary central incisor. We recommend that patients with this dental anomaly should be referred for a detailed medical examination. PMID:2196072

Fleming, P; Nelson, J; Gorlin, R J

1990-06-23

22

Peripheral odontogenic fibroma associated with a dilacerated maxillary central incisor: a case report.  

PubMed

The authors report a case of a 16-year-old male with peripheral odontogenic fibroma (POF) in the anterior maxilla associated with dilaceration of a tooth in its vicinity. A solitary, exophytic and sessile growth was present between the maxillary right central and lateral incisors and extended from the labial mucosa to the palatal gingiva. A periapical radiograph of the maxillary right central incisor revealed a shortened and dilacerated root. The growth was excised and sent for histopathologic examination. A diagnosis of POF (World Health Organization type) was rendered. The clinical and microscopic features are discussed. PMID:23738522

Ramachandra, Srinivas Sulugodu; Baliga, Vidya; Prasad, Umesh Chandra

2011-10-01

23

Management of an intruded primary central incisor with a natural crown under general anesthesia  

PubMed Central

Tooth intrusion is the most common trauma during early infancy. Primary maxillary central incisors are the most affected teeth. There are a few treatment approaches which depend upon the severity of the trauma, and the treatment must be managed professionally. In this case report, a 3-year-old girl with a history of trauma 40 days before referring to our pediatric clinic is presented. Deciduous maxillary right central incisor was intruded through labial and alveolar socket and completely covered with soft tissue. The intruded deciduous incisor tooth was surgically extracted and impression was taken under general anesthesia. The removable partial prosthesis was completed by using the patient's own extracted tooth. Using natural crown on removable prosthesis gives psychological satisfaction to the patient and his/her family, and can be better tolerated since its shape, size, and color are exactly in harmony.

Altunsoy, Mustafa; Bilgin, Mehmet Selim

2014-01-01

24

Association between the Facial Type and Morphology of the Upper Central Incisor in Normal Occlusion Subjects.  

PubMed

Aim: The purpose of this study was to verify the association between the facial type and the morphology of the upper central incisor, to potentially provide a guide for artifcial tooth selection in esthetic and prosthetic rehabilitation. Materials and methods: The sample consisted of 51 lateral teleradiographs (lateral cephalometric radiographs) and cast models of subjects with a naturally optimal occlusion and at least four of the six keys of Andrews, for optimal occlusion. The facial type was defned by two cephalometric measurements (SN.Gn and SN.GoGn) and classifed into dolichofacial, meso- facial and brachyfacial after digitizing the radiographs. The incisor morphology was classifed into quadrangular, oval and triangular after 3D digitizing the models and evaluation of the images by 12 dentists. The evaluation between the examiners was performed by Kappa test. In order to test the differences between the variables, it was used a chi-square test (5%). Results: No signifcant difference (p < 0.05) was found between the studied variables. Conclusion: Facial type was not associated with the morphology of the upper central incisor, considering the methodology and population included in the present study. Clinical signifcance: Using the facial type as a way to select the morphology of the upper central incisor proved to be inadequate in this study. Keywords: Tooth, Artifcial, Cephalometry, Form perception, Incisor. How to cite this article: Paranhos LR, Zaroni M, de Carli JP, Okamoto R, Zogheib LV, Torres FC. Association between the Facial Type and Morphology of the Upper Central Incisor in Normal Occlusion Subjects. J Contemp Dent Pract 2014; 15(1):29-33. Source of support: Nil Confict of interest: None. PMID:24939261

Paranhos, Luiz Renato; Zaroni, Miller; de Carli, João Paulo; Okamoto, Roberta; Zogheib, Lucas Villaça; Torres, Fernando César

2014-01-01

25

Correlation between maxillary central incisor crown morphology and mandibular dental arch form in normal occlusion subjects.  

PubMed

The aim of this study was to evaluate the correlation between the morphology of the mandibular dental arch and the maxillary central incisor crown. Cast models from 51 Caucasian individuals, older than 15 years, with optimal occlusion, no previous orthodontic treatment, featuring 4 of the 6 keys to normal occlusion by Andrews (the first being mandatory) were observed. The models were digitalized using a 3D scanner, and images of the maxillary central incisor and mandibular dental arch were obtained. These were printed and placed in an album below pre-set models of arches and dental crowns, and distributed to 12 dental surgeons, who were asked to choose which shape was most in accordance with the models and crown presented. The Kappa test was performed to evaluate the concordance among evaluators while the chi-square test was used to verify the association between the dental arch and central incisor morphology, at a 5% significance level. The Kappa test showed moderate agreement among evaluators for both variables of this study, and the chi-square test showed no significant association between tooth shape and mandibular dental arch morphology. It may be concluded that the use of arch morphology as a diagnostic method to determine the shape of the maxillary central incisor is not appropriate. Further research is necessary to assess tooth shape using a stricter scientific basis. PMID:22666773

Paranhos, Luiz Renato; Lima, Carolina Souto; da Silva, Ricardo Henrique Alves; Daruge Júnior, Eduardo; Torres, Fernando Cesar

2012-01-01

26

Directions of orthodontic tooth movements associated with external apical root resorption of the maxillary central incisor  

Microsoft Academic Search

External apical root resorption is a multifactorial problem encountered in all disciplines of dentistry, but it is most commonly seen in cases treated orthodontically. Specific tooth movements that are most likely to exacerbate external apical root resorption are poorly understood. Purpose of the present investigation was twofold: (1) to quantify apical and incisal movements of the maxillary central incisor in

Robert J. Parker; Edward F. Harris

1998-01-01

27

Treatment of severe rotations of maxillary central incisors with whip appliance: Report of three cases  

PubMed Central

The routine treatment for rotated maxillary incisor is a fixed appliance, but in some instance the use of this method is impossible. In addition, in only limited cases of rotation, removable appliance is applicable. In this study, the use of a semi-removable appliance is presented, which has some benefits over the other methods. In this study, the corrections of about 70-90° rotation of the maxillary central incisors in different phases of mixed dentition were performed in three patients using whip appliance. This method was performed using a simple removable appliance such as Hawley appliance and whip spring that forced the couple to derotate the tooth. In all cases, treatment was successfully completed in relative short duration. Whip appliance can be recommended as an effective method to correct rotation of maxillary incisor in mixed dentition with several advantages like rapid correction.

Parisay, Iman; Boskabady, Marzie; Abdollahi, Mojtaba; Sufiani, Mostafa

2014-01-01

28

Dual root coverage of severely traumatized maxillary central incisors: a divided soft tissue management approach.  

PubMed

A dual mucogingival treatment is presented in which severely traumatized maxillary central incisors sustained lateral and extrusive luxation injuries in a roadside accident. Injuries resulted in complete loss of the overlying radicular labial cortical plate followed by a gingival soft tissue cleft, which created a Grade II Miller recession defect in relation to the labial aspect of the maxillary central incisors. A multidisciplinary treatment approach was used, including emergency care, endodontic therapy, and sequential dual periodontal soft tissue rehabilitation. Subepithelial connective tissue grafting was carried out using two techniques, which proved successful in achieving complete coverage of the defect sites. This two-stage surgical approach enabled achievement of ample vascularization for soft tissue grafting and enhanced its predictability for optimal outcome. At the 3-year follow-up, clinical and radiographic examination showed a maintainable functional and esthetic status. PMID:21909498

Artzi, Zvi; Chaturvedi, Rashi

2011-10-01

29

Sequelae to trauma to immature maxillary central incisors: a case report.  

PubMed

This case report highlights (i) a rare example of spontaneous apexification despite pulp necrosis and periradicular pathosis, and (ii) pulpal necrosis and periapical pathosis following secondary trauma. The initial trauma occurred in a seven-year-old female who received secondary trauma 4 years later. The diagnosis and management of both maxillary central incisors as well as follow-up assessments for both immature and mature teeth subjected to trauma is discussed. PMID:19021646

Kahler, Bill; Heithersay, Geoffrey S

2008-12-01

30

Simultaneous Replacement of Maxillary Central Incisors with CEREC Biogeneric Reference Technique: A Case Report  

PubMed Central

Biogeneric Reference Technique (BRT) of the CEREC 3D v.3.8 software is an effective technique for single anterior ceramic crowns because it provides computer-controlled match of the tooth form to the contralateral tooth. BRT also enables the fabrication of two or more anterior all-ceramic crowns simultaneously. This clinical report demonstrates the clinical application of BRT for designing and milling two central incisors in one appointment using a single optical impression. After completing the virtual design of the first central incisor, it was copied and a mirror image was created. The second central incisor was designed using this replicated image and therefore a computer-controlled symmetry was obtained. The crowns were milled from monolithic feldspathic ceramic blocks and adhesively luted with dual-cured resin cement following dentin conditioning. At the two-year follow-up appointment, the restorations were intact, no adverse effects were noted, and the resultant appearance was highly satisfactory for the patient. A step-by-step protocol is described from design to cementation of these restorations.

Akgungor, Gokhan; Sen, Deniz; Bal, Eray; Ozcan, Mutlu

2013-01-01

31

Bilateral Agenesis of Permanent Mandibular Central Incisors: Report of Two Cases  

PubMed Central

General dentists most commonly encounter one or more congenitally missing teeth on routine oral examination. Hypodontia and oligodontia are the two most commonly encountered genetic disorders. When one or less than six teeth are missing congenitally they are termed hypodontia. Environmental factors, radiation, trauma, infection, genetic mutations have all been considered as the probable cause for hypodontia. Well documentation of such condition becomes necessary to enrich the knowledge about congenitally missing teeth. How to cite the article: Satish BN, Kumar P, Furquan M, Hugar D, Saraswati FK. Bilateral agenesis of permanent mandibular central incisors: Report of two cases. J Int Oral Health 2014;6(3):103-5.

Satish, B N V S; Kumar, Prashant; Furquan, Mohammad; Hugar, Deepa; Saraswati, F K

2014-01-01

32

Stress distribution of post-core applications in maxillary central incisors.  

PubMed

The purpose of this study was to evaluate the stress distribution in a maxillary central incisor restored with various post-core applications. The study used a three-dimensional finite element method. The tooth was assumed to be endodontically treated with a porcelain crown. Two different sizes of Flexi-post, Cera-post, and Composipost were compared for 200 N palatal and incisal loads. It was determined that, purely from the point of view of strength considerations, core material was determined to be of greater importance than post material or size. Higher elastic moduli of the posts resulted in lower stresses throughout the tooth. PMID:14871043

Yaman, Sis Darendeliler; Karacaer, Ozgül; Sahin, Melin

2004-01-01

33

Implant Prosthetic Rehabilitation with Bone Regenerative Techniques after Fracture of the Upper Central Incisors  

PubMed Central

A case of implant-bone prosthetic rehabilitation, after the fracture of the maxillary central incisors, which had been treated with grafting of a bone substitute, is reported. This case was followed by the normal procedures of implantology within the traditional timeframe for bone regeneration. However, a barrier membrane was not used which shows that even along with the use of graft material a sufficient amount of bone could be achieved for a subsequent rehabilitation. Therefore, after a five-year follow-up period, osseointegration was maintained with no marginal bone loss.

Amato, Massimo; Bruno, Vincenzo; Pantaleo, Giuseppe; Cerutti, Antonio; Spagnuolo, Gianrico; Sammartino, Gilberto

2013-01-01

34

Finite elements study of the Flexi Post and Flexi Flange post systems in a maxillary central incisor.  

PubMed

The use of post and core systems has become an excellent alternative for restoring endodontically treated teeth. The aim of this study was to evaluate the von Mises, maximal compressive and tensile stresses distribution using the Finite Element Method (FEM) on human teeth restored with different post and core systems. The analysis was made on endodontically treated maxillary central incisors. The post systems used in this investigation were the stainless steel or titanium Flexi Post/Flexi Flange. Composite resin was used as core material and resin cement was the cement material of choice to seat a full porcelain crown. The bi-dimensional mathematical model was created from pictures taken from an intact human maxillary central incisor and prefabricated posts. This image was transferred to a personal computer in the MSC/Nastran 4.5 software. A static and linear analysis treatment was performed when a 45 load of 100 N was applied on the lingual surface of the tooth. Based on the results obtained, it can be concluded that the post design and its material can alter the stress pattern distribution. PMID:14569354

Lewgoy, Hugo Roberto; Youssef, Michel Nicolau; Matson, Maurício Rufaiel; Bocangel, Jorge Antônio Javier Saldivar; Netto, Camillo Anauate; Amore, Ricardo

2003-01-01

35

A morphometric analysis of maxillary central incisor on the basis of facial appearance in Korea  

PubMed Central

PURPOSE We aimed to identify a more esthetic width-to-length ratio by analyzing maxillary central incisor of Korean adult population. Information regarding tooth ratio in the Korean population may be useful to clinicians when restoring anterior teeth. MATERIALS AND METHODS A total of 40 men and 40 women were included in this study. The NON-MEDIA group included 40 non-celebrities, who were healthy and 25 to 39 years old, with normal dentofacial appearance. The MEDIA group consisted of 40 celebrities selected only on the basis of their soft-tissue facial appearance. The facial photographs of 40 celebrities were collected from the Internet websites. The width and length of the maxillary central incisor were measured using Adobe Photoshop® 7.0, a software for analysis, measurement and edition of photographs. Data were analyzed statistically using the Independent t-test at 5% statistical significance level. RESULTS The mean ratio for the MEDIA group was 0.77, whereas that of the NON-MEDIA group was 0.88. The difference between the two groups was statistically significant. No significant gender differences were found in the width-to-length ratio in MEDIA group. In NON-MEDIA group, however, there were significant differences between female and male. CONCLUSION After analyzing maxillary anterior teeth of Korean adults, our results were in accordance with the general Western standards of esthetics. A dentist restoring the natural look and beauty of teeth will have to consider those standards.

Ku, Ji-Eun; Yang, Hong-So

2012-01-01

36

Stress Analysis of a Maxillary Central Incisor Restored with Different Posts  

PubMed Central

Objectives To evaluate the effects of different post materials on the stress distribution in an endodontically treated maxillary incisor. Materials and Methods A pseudo 3-dimensional finite element model was created in a labiolingual cross-sectional view of a maxillary central incisor and modified according to five posts with different physical properties consisting stainless steel, titanium, gold alloy, glass fiber (Snowpost), and carbon fiber (Composipost). A 200 N force was then applied from two different directions; a) vertical load on the incisal edge, b) 45 degree diagonal load above the cingulum location. Stress distribution and values were then calculated by considering the pseudo three dimensional von Mises stress criteria. Results Under two loading conditions, post made of steel showed greatest stress concentration at the post/dentin interface followed by titanium, gold alloy, Snowpost and Composipost. However, Composipost, which elastic modulus was closer to the dentin, produced highest stress values at 1/3 cervical area. Conclusions Within the limitation of this simulated mechanical analysis, we can conclude that the physical characteristics of posts were important on stress distributions in post and core applications. Glass fiber post revealed more balanced stress distribution under functional forces.

Adanir, Necdet; Belli, Sema

2007-01-01

37

Surgical Retreatment of an Invaginated Maxillary Central Incisor Following Overfilled Endodontic Treatment: A Case Report  

PubMed Central

This case report presents the periapical surgical retreatment of an Oehlers Class III invaginated maxillary central incisor with extruded root canal filling into the periapical lesion. After local anesthesia, a full-thickness mucoperiosteal flap was reflected, and the granulomatous tissue and extruded gutta-percha points were curetted carefully. A deep and wide root-end cavity was prepared and filled with mineral trioxide aggregate (MTA). At 6 months and 2 years after the treatment, the tooth exhibited no clinical symptoms, and the radiograph performed during the 2-year follow-up showed a complete periapical healing around the root end. The present report indicates that MTA retrofilling can be used successfully in the surgical retreatment of dens invaginatus type III cases in which the invagination exits apically.

Ozbas, Hakan; Subay, Rustem Kemal; Ordulu, Melike

2010-01-01

38

Multidisciplinary Approach in Management of Fractured Central Incisor through Composite Plug Stabilization - A Case Report  

PubMed Central

Crown fracture is the most frequent type of traumatic injury in permanent dentition. Traumatized anterior teeth requires quick functional and esthetic repair. Traditionally such injuries have been restored with conventional post-core and crown techniques after endodontic treatment. This article presents an innovative technique of managing a complicate crown fracture of anterior tooth where plain orthodontic band was used for stabilization and post endodontic restoration was done with adhesively luted fiber reinforced composite post through fragment and composite plug stabilization. How to cite this article: Sushil K C, Rao A, Sheila K, Hanumanth R G. Multidisciplinary Approach in Management of Fractured Central Incisor through Composite Plug Stabilization - A Case Report. J Int Oral Health 2013; 5(1):79-82.

C, Sushil Kumar; Rao, Amit; K, Sheila; G, Hanumanth Reddy

2013-01-01

39

Initial forces generated by three types of thermoplastic appliances on an upper central incisor during tipping.  

PubMed

The force properties of thermoformed appliances have not been systematically investigated. Therefore, the aim of the present study was to quantify the forces delivered by thermoplastic appliances manufactured from three different materials, with the same thickness, on a central upper incisor, during tipping. Five identical appliances were manufactured from three different materials all with a thickness of 1.0 mm (Ideal Clear, Erkodur, and Biolon). For measuring the forces, an isolated measuring tooth, as part of a standardized resin model incorporated in a newly developed measuring device, was tipped in nine 2.7 arc minute (0.04629 degree) steps, from 0 to 0.416 degrees in the vestibular and palatal directions around a rotational axis through the virtual apex, after positioning an appliance on the model. For statistical analysis, the force components Fx/tipping and Fz/intrusion at a displacement of +/-0.151 mm from the incisor edge were determined. Means and standard deviations (SDs) were calculated. The Kruskal-Wallis test for overall effects and the Wilcoxon two-sample test for individual group pairings were used (P < 0.05 significance level). The mean Fx forces ranged from -2.82 N (SD 0.62) to 5.42 N (SD 0.56). The mean Fz forces were between -0.14 N (SD 0.52) and -2.3 N (SD 0.43). The highest intrusive forces were measured during vestibular displacement of the measuring tooth. The forces delivered by the Biolon appliance were found to be much greater (P < 0.01) than those of the other materials. The forces delivered by the materials investigated were mostly higher than those stated in the literature. PMID:19525441

Hahn, Wolfram; Fialka-Fricke, Julia; Dathe, Henning; Fricke-Zech, Susanne; Zapf, Antonia; Gruber, Rudolf; Kubein-Meesenburg, Dietmar; Sadat-Khonsari, Reza

2009-12-01

40

Relationship between the morphology of the maxillary central incisor and horizontal and vertical measurements of the face.  

PubMed

Purpose: In order to assist in the selection of artificial teeth for complete dentures, this study aimed to assess the relationship between horizontal and vertical measurements of the face and the morphology of the maxillary central incisor. Materials and Methods: This was a study of 50 plaster casts and 100 teleradiographs - 50 in lateral norm and 50 in frontal norm, belonging to 50 individuals, Caucasian, with a naturally optimal occlusion, matching at least four of the six keys of Andrews. Images of the upper central incisors were obtained by scanning the plaster casts (three-dimensional) and subjectively classified by three examiners as oval, triangular or quadrangular. Facial measures (vertical and horizontal) were defined by means of teleradiographs. In order to check inter-examiner agreement on the classification of central incisor, the Kappa test was used. To verify whether data had normal distribution, the Kolmogorov-Smirnov test was used (?P > 0.2) was used. One-way analysis of variance was employed to assess the association between variables (P > 0.05). Results: When vertical measurements were compared with the three incisor shapes, there was no statistically significant difference (P > 0.05): Triangular (0.54), oval (0.63) and quadrangular (0.51). Similarly, no difference (P > 0.05) was found for facial width (139.08, 143.37, 141.65), maxillary width (76.68, 78.99, 76.91) and mandibular width (103.47, 105.50, 103.11). Conclusions: The majority of cases showed that horizontal and vertical measurements of the face cannot be used as a reference for determining the morphology of the maxillary central incisor crown. It is relevant to analyze and compare other morphological structures to improve the oral health-related quality of life for the conventional denture wearer. PMID:24992847

Furtado, Gisela Crippa; Furtado, Alvaro; El Haje, Ossam Abu; Butignon, Luis Eduardo; Pesqueira, Aldieris Alves; Paranhos, Luiz Renato

2014-01-01

41

Nasopalatine canal position relative to the maxillary central incisors: a cone beam computed tomography assessment.  

PubMed

The aim of this study was to determine the proximity of the nasopalatine canal (NPC) to the maxillary central incisor root (MCIR). The study included 120 cone beam computed tomography scans obtained from the Center for Implant Dentistry, Loma Linda University, between June 2006 and September 2009. They were equally distributed into six groups: (1) 21- to 40-year-old men, (2) 21- to 40-year-old women, (3) 41- to 60-year-old men, (4) 41- to 60-year-old women, (5) 61- to 80-year-old men, and (6) 61- to 80-year-old women. The closest distances between the NPC and the MCIR (NPC-to-MCIR) were measured at the midroot (bisecting palatal cementoenamel junction to root apex) and the apex levels. Differences between the groups were analyzed using a t test and 1-way analysis of variance at a significance level of ? = .05. The overall mean NPC-to-MCIR distances at the midroot and apex levels were 3.05 ± 1.64 and 5.22 ± 1.56 mm, respectively. The modes of the NPC-to-MCIR distances at the midroot and apex levels were in the range of 1.01-2.00 mm and 4.01-5.00 mm, respectively. The mean NPC-to-MCIR distance was significantly greater in men than in women at the midroot level (P < .05) but not at the apex level (P > .05). The mean NPC-to-MCIR distance was significantly shorter for the youngest age group than the other two age groups at the midroot level (P < .05). However, at the apex level, the youngest age group had a significantly shorter distance compared with the oldest age group (P < .05) but not the middle age group (P > .05). The results of this study suggest that, to avoid NPC penetration, more care must be exercised during immediate implant placement at the midroot level of a maxillary central incisor in women and younger patients because of the root proximity to the NPC. Tapered implants may also be beneficial in such situations. PMID:20932126

Chatriyanuyoke, Pakawat; Lu, Chun-I; Suzuki, Yusuke; Lozada, Jaime L; Rungcharassaeng, Kitichai; Kan, Joseph Y K; Goodacre, Charles J

2012-12-01

42

Stress distributions in maxillary central incisors restored with various types of post materials and designs.  

PubMed

Different dental post designs and materials affect the stability of restoration of a tooth. This study aimed to analyse and compare the stability of two shapes of dental posts (parallel-sided and tapered) made of five different materials (titanium, zirconia, carbon fibre and glass fibre) by investigating their stress transfer through the finite element (FE) method. Ten three-dimensional (3D) FE models of a maxillary central incisor restored with two different designs and five different materials were constructed. An oblique loading of 100N was applied to each 3D model. Analyses along the centre of the post, the crown-cement/core and the post-cement/dentine interfaces were computed, and the means were calculated. One-way ANOVAs followed by post hoc tests were used to evaluate the effectiveness of the post materials and designs (p=0.05). For post designs, the tapered posts introduced significantly higher stress compared with the parallel-sided post (p<0.05), especially along the centre of the post. Of the materials, the highest level of stress was found for stainless steel, followed by zirconia, titanium, glass fibre and carbon fibre posts (p<0.05). The carbon and glass fibre posts reduced the stress distribution at the middle and apical part of the posts compared with the stainless steel, zirconia and titanium posts. The opposite results were observed at the crown-cement/core interface. PMID:24834856

Madfa, A A; Kadir, M R Abdul; Kashani, J; Saidin, S; Sulaiman, E; Marhazlinda, J; Rahbari, R; Abdullah, B J J; Abdullah, H; Abu Kasim, N H

2014-07-01

43

Nonlinear finite element analysis of the vibration characteristics of the maxillary central incisor related to periodontal attachment  

Microsoft Academic Search

The vibration characteristics of a maxillary central incisor were investigated by using the finite element method (FEM) according\\u000a to nonlinear behavior of the human periodontal ligament (PDL). The effect of alveolar bone loss was also studied to obtain\\u000a the relationship between the vibration property of the tooth in the periodontal system and the level of periodontal attachment\\u000a for assessing the

Haitao Xin; Yulong Li; Lingcheng Zhao; Weiguo Guo

2009-01-01

44

Using a dental operating microscope for endodontic management of a mandibular central incisor with 3 root canals.  

PubMed

Endodontic management of teeth with aberrant root canal morphology can be challenging. This article presents a case in which multiple angulated radiographs and a dental operating microscope clearly revealed the presence of 3 root canals in a right mandibular central incisor with 2 different canal patterns. This case report emphasizes the importance of utilizing a dental operating microscope to understand unusual root canal morphology. PMID:23928435

Aswinkumar, Vijayakumar; Nandini, Suresh; Velmurgan, Natanasabapathy

2013-08-01

45

Treatment of class II malocclusion with open bite and absence of central maxillary incisor lost by trauma aided by use of orthodontic mini-implants.  

PubMed

The aim of this article is to report the clinical case of non-surgical treatment of a Class II malocclusion with anterior open bite, associated with absence of a maxillary central incisor avulsed due to trauma. Treatment proceeded with the use of orthodontic mini-implants as an anchorage device for intrusion of the maxillary molars and for mesial movement of the lateral incisor to replace the central incisor. Treatment resulted in good occlusion, with anterior and lateral guides, enhancement of the facial profile, and good dental esthetic appearance without the need for prosthetic treatment. The treatment outcome was satisfactory but needs long-term or permanent retention. PMID:23331427

Pithon, Matheus Melo

2014-02-01

46

Glossectomy as an adjunct to correct an open-bite malocclusion with shortened maxillary central incisor roots.  

PubMed

A young man, 19 years of age, with the chief complaint of an anterior open bite, came for orthodontic treatment with a skeletal Class I relationship, anterior open bite, shortened maxillary incisor roots, and relative macroglossia. The malocclusion was treated by extracting the maxillary first premolars and using a fixed edgewise appliance. A partial glossectomy was performed before the orthognathic surgery with a 3-piece segmental LeFort I mandibular setback, and advancement was achieved with a reduction genioplasty. A functional and esthetic occlusion with an improved facial profile was established, and the apex of the maxillary left central incisor became slightly rounded after prolonged and significant tooth movement. Four years after treatment, there was occlusal stability of the results, and no further root shortening was observed. PMID:23810054

Tanaka, Orlando Motohiro; Guariza-Filho, Odilon; Carlini, João Luiz; Oliveira, Dauro Douglas; Pithon, Matheus Mello; Camargo, Elisa Souza

2013-07-01

47

A 5-year longitudinal study of survival rate and periodontal parameter changes at sites of dilacerated maxillary central incisors  

PubMed Central

Background Although dental dilaceration disinclusion is an accepted treatment modality, few studies have evaluated the prognosis for dilacerated maxillary incisors and changes in clinical periodontal parameters still need to be demonstrated. The objectives of this study were to evaluate the prognosis and changes in clinical attachment level (CAL), probing depth (PD), and soft tissue recession (REC) for disincluded dilacerated maxillary incisors. Methods Ten impacted dilacerated teeth were scheduled for disinclusion. Five of them were disincluded with the apically repositioned flap technique and the other five with the closed eruption technique and brought into alignment with light orthodontic forces. Results All the dilacerated teeth were disincluded as planned. CAL, PD, and REC were the same as natural teeth. Among the two surgical techniques, no statistically significant differences have been found. Conclusion The choice to disinclude dilacerated central maxillary incisors reached the goals planned. Periodontal parameters obtained in a short- and long-term follow-up allow to affirm that the disinclusion of dilacerated teeth has a good survival rate.

2014-01-01

48

Treatment of a maxillary central incisor with class III invasive cervical resorption and compromised ferrule: a clinical report.  

PubMed

This clinical report presents the treatment of a maxillary central incisor with class III invasive cervical resorption and a compromised ferrule. Nonsurgical endodontic therapy combined with periodontal surgery was provided for debridement. Direct light-polymerizing resin-modified glass ionomer cement and a zirconia crown were used to repair the defect. Symptomatic endodontic complication was diagnosed with localized cone beam computed tomography at 6-month follow-up, and periapical microsurgery was rendered. The patient was followed-up for 30 months after treatment and had no further complications. PMID:24423455

Harris, Bryan T; Caicedo, Ricardo; Lin, Wei-Shao; Morton, Dean

2014-05-01

49

Persistent endodontic lesion due to complex cementodentinal tears in a maxillary central incisor--a case report.  

PubMed

The cementodentinal tear is rarely detected by noninvasive procedures owing to its clinical picture simulating a root fracture or a periodontal or endodontic lesion. We present a case of complex cementodentinal tears in a 79-year-old woman who presented a repeated swelling at the labial mucosa of the left maxillary central incisor for 6 months. Periapical radiographs demonstrated a vertical radiolucent fracture line extending from the root apex along the mesial aspect of the root to near the middle portion of the root of the left maxillary central incisor. Because endodontic re-treatment failed to cure the disease, periapical surgery was performed, and 2 fractured U-shaped root fragments around the apical root surface were removed. Histologic examination showed that the 2 fractured root fragments were composed mainly of the dentin covered by a thin layer of the cementum and overlying periodontal ligament tissue, suggesting cementodentinal tears. A swelling recurred 8 months after the initial operation. Therefore, a second periapical surgery was performed. Although no obvious fracture line was observed around the root surface, the second surgery did not cure the disease, either. A persistent small swelling was noted at the alveolar mucosa of the affected tooth during the follow-up. We conclude that although a cementodentinal tear can be detected by a careful radiographic examination, its clinical outcome is not predictable by surgical removal only. PMID:17449287

Tai, Tseng-Fang; Chiang, Chun-Pin; Lin, Chun-Pin; Lin, Chiu-Chun; Jeng, Jiiang-Huei

2007-06-01

50

Evaluation of the mesio-buccal gingival sulcus depth of the upper central incisors in patients submitted to surgically assisted maxillary expansion  

Microsoft Academic Search

Proposition  The aim of this study was to evaluate the modifications that occurred in the mesio-buccal gingival sulcus depth of the upper\\u000a central incisors during a 3-year post-operative period.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  The mesio-buccal gingival sulcus depth of the upper central incisors of patients submitted to surgically assisted maxillary\\u000a expansion (SAME) was measured by using a periodontal probe, both in the pre-operative period and

Diogo Souza Ferreira Rubim de Assis; Paulo Domingos Ribeiro Jr; Marco Antônio Húngaro Duarte; Eduardo Sanches Gonçales

2011-01-01

51

Replantation of an immature permanent central incisor following pre-eruptive traumatic avulsion.  

PubMed

Tooth avulsion represents 0.5-16% of traumatic injuries. Avulsion of a pre-eruptive left permanent maxillary incisor in a 6-year-old boy is presented. The immature tooth was replanted after rinsing with saline following 10 min dry extra-oral time. This case report describes treatment and a 2-year follow-up of the tooth. During the follow-up period, continuation of root development, pulp revascularization, and irregular dentin formation were demonstrated. The tooth is vital, functional, and esthetic. To the best of our knowledge, no such case of replantation of a pre-eruptive tooth has been reported previously. PMID:18821947

Davidovich, Esti; Moskovitz, Moti; Moshonov, Joshua

2008-10-01

52

Incisors' proportions in smile esthetics  

PubMed Central

Aims: To determine whether alteration of the maxillary central and lateral incisors’ length and width, respectively, would affect perceived smile esthetics and to validate the most esthetic length and width, respectively, for the central and lateral incisors. Materials and Methods: Photographic manipulation was undertaken to produce two sets of photographs, each set of four photographs showing the altered width of the lateral incisor and length of the central length. The eight produced photographs were assessed by laypeople, dentists and orthodontists. Results: Alteration in the incisors’ proportion affected the relative smile attractiveness for laypeople (n=124), dentists (n=115) and orthodontists (n=68); dentists and orthodontists did not accept lateral width reduction of more than 0.5 mm (P<0.01), which suggests that the lateral to central incisor width ratio ranges from 54% to 62%. However, laypeople did not accept lateral width reduction of more than 1 mm (P<0.01), widening the range to be from 48% to 62%. All groups had zero tolerance for changes in central crown length (P<0.01). Conclusion: All participants recognized that the central incisors’ length changes. For lateral incisors, laypeople were more tolerant than dentists and orthodontists. This suggests that changing incisors’ proportions affects the relative smile attractiveness.

Alsulaimani, Fahad F; Batwa, Waeil

2013-01-01

53

Orthodontic movement of a maxillary central incisor with a horizontal root fracture treated using an intra-radicular fibre splint.  

PubMed

This paper reports the case of a 15-year-old boy with a horizontal root fracture in the left maxillary central incisor along with class II division 1 malocclusion for whom a fixed orthodontic treatment was planned. The fracture was present at the junction of apical and middle-third as a result of trauma 2 years back. No splinting was carried out at that time and the tooth was found to be vital, asymptomatic and showed a type-1 repair pattern. An intentional root canal treatment was carried out for placement of an intra-radicular fiber splint, nearly 3 mm beyond the fracture line. Orthodontic treatment was initiated after a month; to which the fractured and splinted tooth responded successfully. This report highlights the successful use of an intra-radicular splint for horizontally fractured tooth requiring orthodontic treatment. PMID:24015026

Kapur, Aditi; Utreja, A; Goyal, A; Pankaj, P

2013-04-01

54

The restoration of a maxillary central incisor fracture with the original crown fragment using a glass fiber-reinforced post: a clinical report.  

PubMed

This report describes an esthetic, conservative, and economical alternative restoration technique for a fractured central incisor using the patient's own tooth crown piece and a bondable reinforcement glass fiber. Although the long-term durability of this adhesive post core restoration remains unknown, it remains successful after 1 year. PMID:19021643

Durkan, Rukiye Kaplan; Ozel, M Birol; Celik, Davut; Ba?i?, Bora

2008-12-01

55

Agreement in the diagnosis of dental fluorosis in central incisors performed by a standardized photographic method and clinical examination.  

PubMed

The aim of this study was to assess agreement in the diagnosis of dental fluorosis performed by a standardized digital photographic method and a clinical examination (gold standard). 49 children (aged 7-9 years) were clinically evaluated by a trained examiner for the assessment of dental fluorosis. Central incisors were evaluated for the presence or absence of dental fluorosis and were photographed with a digital camera. Photographs were presented to three pediatric dentists, who examined the images. Data were analyzed using Cohen's kappa and validity values. Agreement in the diagnosis performed by the photographic method and clinical examination was good (0.67) and accuracy was 83.7%. The prevalence of dental fluorosis was reported to be higher in the clinical examination (49%) compared with the photographic method (36.7%). The photographic method presented higher specificity (96%) than sensitivity (70.8%), a positive predictive value (PPV) of 94.4% and a negative predictive value (NPV) of 77.4%. The diagnosis of dental fluorosis performed using the photographic method presented high specificity and PPV, which indicates that the method is reproducible and reliable for recording dental fluorosis. PMID:19488486

Martins, Carolina Castro; Chalub, Loliza; Lima-Arsati, Ynara Bosco; Pordeus, Isabela Almeida; Paiva, Saul Martins

2009-05-01

56

Influence of type of luting cement used with all-ceramic crowns on load capability of post-restored endodontically treated maxillary central incisors  

Microsoft Academic Search

Adhesive luting of the final restorations is supposed to support the overall strength of post-endodontically restored teeth.\\u000a For evaluating adhesive vs conventional cementation, the load capability of adhesively restored endodontically treated teeth\\u000a (ETT) with glass fibre-reinforced composite posts (GFRCP), resin composite cores and all-ceramic crowns was determined. Thirty-two\\u000a caries-free human upper, central incisors were randomly assigned to four groups, endodontically

Anja Preuss; Martin Rosentritt; Roland Frankenberger; Florian Beuer; Michael Naumann

2008-01-01

57

Clinical course and implications of congenital nasal pyriform stenosis and solitary median maxillary central incisor in a newborn: a case report  

PubMed Central

Introduction Congenital nasal pyriform aperture stenosis and solitary median maxillary central incisor are uncommon anomalies and are associated with further malformations. Solitary median maxillary central incisor itself has initially no impact on a child’s health, but congenital nasal pyriform aperture stenosis is a potentially life-threatening condition. Case presentation A Caucasian baby boy showed severe dyspnoea and was intubated orotracheally. Multiple anomalies were detected, including urogenital and craniofacial malformations. Computed tomography scans revealed congenital nasal pyriform aperture stenosis with a diameter of 4.9mm and a solitary median maxillary central incisor. A 3.0mm tube was inserted in his left nasal cavity, and the baby was able to breathe sufficiently and spontaneously. The nasal tube was removed after seven days, and the baby was discharged under application of decongestant drops. After seven months, the baby was readmitted with respiratory distress, and surgery was carried out using an intraoral sublabial approach. The stenotic area of the pyriform aperture was widened, and 3.0mm tubes were inserted in both nasal cavities for 10 days. Over a period of six months, no further respiratory distress has occurred. Conclusions The decision to perform surgery was delayed since the baby’s nasal breathing was adequate as a result of the insertion of a nasal tube. Since treatment depends on the severity of symptoms, it is appropriate in some cases to take a conservative approach at first, and to keep surgery as a last resort. Once a conservative approach has been selected for congenital nasal pyriform aperture stenosis, awareness of the life-threatening nature of the condition should be kept in mind, and a surgical approach must still be taken into account.

2014-01-01

58

The effect of central incisor's root proximity to the cortical plate and apical root resorption in extraction and non-extraction treatment  

PubMed Central

Aims: The present study was conducted to investigate the relevance of cortical plate proximity of maxillary central incisor root, maxillary alveolar bone width, and the apical root resorption in extraction and non-extraction orthodontically treated cases. Further, the correlation between the apical root resorption and the various parameters was investigated. Materials and Methods: A total of 80 lateral head cephalographs, 40 pre-treatment and 40 post-treatment, of orthodontic subjects with a mean age of 15 years treated with fixed standard edgewise appliance were obtained. All subjects were divided into two groups as extraction and non-extraction cases. Twelve linear and three angular parameters were measured and evaluated. The paired “t”-test, Pearson's correlation coefficient, and the stepwise regression analysis were done to test the relationship between the apical root resorption and the various parameters. Results and Conclusions: The study revealed slightly greater amount of apical root resorption in extraction subjects as compared to non-extraction subjects. However, no statistically significant difference was found between the two treatment modalities. In extraction subjects, the apical root resorption was directly proportional to the pre-treatment length of maxillary central incisor and inversely proportional to the root width in apical one-third region, though there was a weak correlation. In non-extraction subjects, the pre-treatment anteroposterior position of the root apex of maxillary central incisor in the alveolar bone, in combination with its root width in the apical one-third region formed the predictive factors for the variance in the amount of the apical root resorption, though there was a weak correlation. Furthermore, the changes in the alveolar widths at the root apex and mid-root region were considered as predictive factors for the amount of apical root resorption during extraction and non-extraction treatment, respectively.

Agarwal, Akhil; Sharma, Vijay P; Singh, Gulshan K; Tikku, Tripti; Agarwal, Nidhi; Mengi, Arvind

2014-01-01

59

Management of recently traumatized maxillary central incisors by partial pulpotomy using MTA: Case reports with two-year follow-up  

PubMed Central

In traumatized, young, permanent teeth, pulpotomy is classically undertaken to promote apexogenesis. The objective is to promote root development and apical closure. Once root end development and apical closure is achieved, the root canal treatment is completed. However, it has been suggested that mere pulp exposure does not cause pulpitis in the absence of bacteria. Recent studies have proposed that as long as a good seal is ensured, root canal treatment may not be necessary following pulpotomy. In this article we report two cases of traumatized, fully matured, maxillary permanent central incisors, which have been treated with mineral trioxide aggregate following partial pulpotomy, with a two-year follow-up.

Abarajithan, M.; Velmurugan, N.; Kandaswamy, D

2010-01-01

60

Replacement of a fractured upper central incisor with an implant-supported crown: a step-by-step approach to achieve acceptable esthetics.  

PubMed

Implant-supported restorations in the upper anterior segment need to meet biological, functional, and esthetic requirements to be successful. Bone availability and soft-tissue characteristics in the area of implant placement are crucial for achieving maximum success. This article describes the steps involved in replacing a fractured upper central incisor with an implant-supported crown. Using surgical techniques involving extraction socket preservation/augmentation and connective tissue grafting, ideal positioning of the implant was possible and gingival contours were idealized. With this multiple step treatment, the final restoration met biological and functional requirements and its esthetic results were maximized. PMID:16646393

Camargo, Paulo M; Melnick, Philip R; Suleimanagich, Omer; Carnio, Joao G P; Camargo, Luciano M

2006-04-01

61

Histomorphometric analysis of inflammatory response and necrosis in re-implanted central incisor of rats treated with low-level laser therapy.  

PubMed

Low-level laser therapy is a tool employed in the management of post-operative inflammation process and in the enhancement of reparative process. The aim of the study was to perform histological evaluation of dental and periodontal ligament of rats central upper-left incisor teeth re-implanted and irradiated with low-level laser (InGaAl, 685 nm, 50 J/cm(2)) 15, 30, and 60 days after re-implantation. Seventy-two male rats had the central upper left incisor removed and kept for 15 min on dry gauze before replantation. Laser was irradiated over the root surface and empty alveolus prior replantation and over surrounding mucosa after the re-implantation. After histological procedures, all slices were analyzed regarding external resorption area and histological aspects. We observed an increase of root resorption (p?

Vilela, Rianne Gomes; Gjerde, Kjersti; Frigo, Lucio; Leal Junior, Ernesto Cesar Pinto; Lopes-Martins, Rodrigo Alvaro Brandão; Kleine, Brígida Mônica; Prokopowitsch, Igor

2012-05-01

62

Endodontic and Esthetic Management of a Dilacerated Maxillary Central Incisor Having Two Root Canals Using Cone Beam Computed Tomography as a Diagnostic Aid  

PubMed Central

Traumatic injuries to the primary dentition are quite common. When primary teeth are subjected to trauma, force transmission and/or invasion of the underlying tooth germs lying in close proximity can result in a variety of disturbances in the permanent successors. Few of these disturbances include hypoplasia, dilaceration, or alteration in the eruption sequence and pattern. Dilaceration is defined as an angulation or sharp bend or curve in the linear relationship of the crown of a tooth to its root. A rare case of maxillary left central incisor having crown dilaceration and Vertucci's type II canal configuration with symptomatic periapical periodontitis is reported. Cone beam computed tomography was used for better understanding of the anomaly and complicated root canal morphology. The tooth was successfully managed by nonsurgical root canal therapy and restoration with resin composite to restore esthetics.

Sharma, Sarang; Grover, Shibani; Sharma, Vivek; Srivastava, Dhirendra; Mittal, Meenu

2014-01-01

63

Endodontic and esthetic management of a dilacerated maxillary central incisor having two root canals using cone beam computed tomography as a diagnostic aid.  

PubMed

Traumatic injuries to the primary dentition are quite common. When primary teeth are subjected to trauma, force transmission and/or invasion of the underlying tooth germs lying in close proximity can result in a variety of disturbances in the permanent successors. Few of these disturbances include hypoplasia, dilaceration, or alteration in the eruption sequence and pattern. Dilaceration is defined as an angulation or sharp bend or curve in the linear relationship of the crown of a tooth to its root. A rare case of maxillary left central incisor having crown dilaceration and Vertucci's type II canal configuration with symptomatic periapical periodontitis is reported. Cone beam computed tomography was used for better understanding of the anomaly and complicated root canal morphology. The tooth was successfully managed by nonsurgical root canal therapy and restoration with resin composite to restore esthetics. PMID:24955260

Sharma, Sarang; Grover, Shibani; Sharma, Vivek; Srivastava, Dhirendra; Mittal, Meenu

2014-01-01

64

Ex vivo fracture resistance of endodontically treated maxillary central incisors restored with fiber-reinforced composite posts and experimental dentin posts  

PubMed Central

Aim: To compare the fracture resistance of teeth restored with fiber-reinforced composite (FRC) posts and experimental dentin posts milled from human root dentin. Materials and Methods: Thirty maxillary central incisors were divided into three groups of ten each. Twenty teeth were restored with FRC posts and solid dentin posts and numbered as Groups 2 and 3 respectively while Group 1 acted as the control, without any post. The teeth were loaded at 135° angle to their long axes after core build-up and the failure loads were recorded. Results: One-way Analysis of Variance (ANOVA) and Bonferroni multiple comparisons revealed a significant difference among test groups with the control group showing the highest fracture resistance, followed by the dentin post group and lastly the FRC post group. Conclusions: Teeth restored with dentin posts exhibited better fracture resistance than those restored with FRC posts.

Kathuria, Ambica; Kavitha, M; Khetarpal, Suchit

2011-01-01

65

Platyrrhine incisors and diet.  

PubMed

Despite the relatively large size of anthropoid incisors in relation to the remainder of the dental arcade, and their prominent role in the preprocessing of food prior to ingestion, comparatively little is known about the functional morphology of anthropoid incisor shape and crown curvature. The relationship between incisor allometry and diet is well documented for both platyrrhines and catarrhines; however, similar relationships between incisor shape and crown curvature have to date only been reported for living and fossil members of the superfamily Hominoidea. Given the limited taxonomic diversity among the extant members of that group, it is difficult to firmly establish the relative influence of phylogeny and dietary function in the governance of incisor crown curvature. Unlike hominoids, which are represented by only five living genera, extant platyrrhines are a more varied group that includes 16 ecologically diverse genera. In an effort to clarify the functional relationship between maxillary and mandibular incisor crown curvature and diet, this study uses high resolution polynomial curve fitting to quantify mesiodistal and cervicoincisal curvature for a taxonomically diverse platyrrhine sample (n = 133 individuals representing 18 taxa) with well documented dietary behavior. Results were consistent with prior analyses of hominoid incisor curvature and identify a significant and positive correlation between incisor crown curvature and diet such that increasing curvature is associated with a proportionate increase in frugivory. These results are independent confirmation of the results reported from a previous analysis of hominoid incisor curvature and provide new evidence to suggest that diet is the primary governing factor influencing anthropoid incisor curvature. PMID:22610900

Deane, Andrew

2012-06-01

66

Proton microprobe assessment of the distribution of fluoride in the enamel and dentine of developing central incisors of sheep and changes induced by daily fluoride supplements.  

PubMed

Ten sheep were given 0.5 mg fluoride (F) and 10 sheep 0.2 mg F/kg body wt orally for periods of 1-6 months while 8 sheep received no additional F. One incisor from each sheep was sectioned longitudinally in the midline and, using the proton microprobe, multiple scans for calcium and F were made across the enamel and dentine. F was determined by proton-induced gamma-ray emission and calcium by X-ray emission. Tooth length and hence the stage of ameloblast activity for each of the 28 teeth at the start of the experiment was determined using a tetracycline marker. In addition, the stage of enamel development of the eight control teeth (no dietary F) at the time of their extraction was assessed from their macroscopic appearance. Continuous changes in F levels occurred in both enamel and dentine throughout tooth development and also in the mature enamel and associated dentine after ameloblast regression. All scans for all stages of tooth development and all F treatments showed a high F concentration at the enamel surface. Early in the secretory phase, a wide-based F peak occupied the entire width of the enamel with a similar F peak in the dentine. In the control teeth, no consistent increase in F concentration occurred at the enamel surface during later development. When F supplements were started early in the maturation phase an increase in F concentration only at the enamel surface was recorded. When F supplements were also given during the secretory phase, higher F concentrations were recorded not only at the enamel surface but also for the inner enamel and dentine plateau. These findings, based on a small number of sheep, indicate that further research is needed to clarify the method and control of F uptake and to determine the changes in these processes during the different stages of tooth development. PMID:7639647

Suckling, G; Coote, G E; Cutress, T W; Gao, J

1995-05-01

67

Measuring rodent incisors from scats can increase accuracy of predator diet studies. An illustration based on island cats and rats.  

PubMed

Non-invasive diet studies, which are a simple but important tool to understand trophic interactions inside ecosystems, need to be as detailed as possible. Determining the precise biomass of ingested prey is a key to obtaining not only a better understanding of the amount of food really ingested but also the predator-prey interactions. It is particularly relevant in the case of rodents, because they are often a predominant prey in carnivores' diet and can differ widely in biomass. This study demonstrates how an original and simple method for measuring rat incisors found in cat scats produces measurements which can be correlated with rat weight. This correlation, used in a field application, made it possible to: (i) calculate a more accurate biomass of rats in cat diets and thus obtain a better estimation of the proportion of rats compared to other prey in cat diets; (ii) show that cats preferentially ate smaller rats, indicating that the use of the mean weight of rodents sampled by trap-lines may induce a significant bias in the biomass calculation. Likewise, a correlation between rat lens weight and incisor measurements was found. Using this correlation, it should be possible to estimate the age of the rats eaten by cats and obtain a better understanding of the impact of predators on prey population dynamics. PMID:18722988

Bonnaud, Elsa; Vidal, Eric; Zarzoso-Lacoste, Diane; Torre, Franck

2008-09-01

68

Molar Incisor Hypomineralization, Prevalence, and Etiology  

PubMed Central

Aim. To evaluate the prevalence and possible etiological factors associated with molar incisor hypomineralization (MIH) among a group of children in Jeddah, Saudi Arabia. Methods. A group of 8-12-year-old children were recruited (n = 267) from the Pediatric Dental Clinics at the Faculty of Dentistry, King Abdulaziz University. Children had at least one first permanent molar (FPM), erupted or partially erupted. Demographic information, children's medical history, and pregnancy-related data were obtained. The crowns of the FPM and permanent incisors were examined for demarcated opacities, posteruptive breakdown (PEB), atypical restorations, and extracted FPMs. Children were considered to have MIH if one or more FPM with or without involvement of incisors met the diagnostic criteria. Results. MIH showed a prevalence of 8.6%. Demarcated opacities were the most common form. Maxillary central incisors were more affected than mandibular (P = 0.01). The condition was more prevalent in children with history of illnesses during the first four years of life including tonsillitis (P = 0.001), adenoiditis (P = 0.001), asthma (P = 0.001), fever (P = 0.014), and antibiotics intake (P = 0.001). Conclusions. The prevalence of MIH is significantly associated with childhood illnesses during the first four years of life including asthma, adenoid infections, tonsillitis, fever, and antibiotics intake.

Allazzam, Sulaiman Mohammed; Alaki, Sumer Madani; El Meligy, Omar Abdel Sadek

2014-01-01

69

Interdisciplinary treatment including forced extrusion and reintrusion of a traumatized mandibular incisor for a patient with Class II Division 1 skeletal open bite.  

PubMed

A woman with Class II Division 1 long-face syndrome characteristics had a history of facial trauma, dentoalveolar fracture of her mandibular anterior teeth, and temporomandibular joint pain. The pretreatment apical radiograph showed a large area of external root resorption of the mesial surface of the mandibular left central incisor. To arrest the external root resorption, the mandibular left central incisor was extruded. During extrusion, sequential apical radiographs were taken. As the tooth moved away from the site of osteoclastic activity, resorption ceased, and repair took place on the root surface. At this time, the mandibular left central incisor was intruded, the mesial defect self-repaired, the tooth remained vital, and the periodontial ligament was intact. The biologic bases for this cessation of resorption and the repair of the tooth's surface are presented. PMID:14765060

Arvystas, Michael G; Chivian, Noah

2004-02-01

70

Resin-bonded cantilever and twist-flex wire for maxillary incisor lost due to trauma.  

PubMed

A simple appliance to replace an 8-year-old's central incisor, which was decoronated after a trauma, is described. A natural tooth cantilevered pontic bonded to the adjacent central incisor may be an immediate solution. This appliance may be used when clinical conditions do not allow for the use of a conservative removable or fixed partial denture. PMID:22436431

Peretz, Benjamin; Nuni, Eyal

2012-01-01

71

Post-traumatic impaction of maxillary incisors: diagnosis and treatment  

PubMed Central

Summary Aim To provide clinicians with useful information for immediate diagnosis and management of impacted maxillary incisors due to trauma. Methods We present a case of post-traumatic impaction of a central right maxillary incisor in a young patient. The treatment plan consisted in the interceptive management (surgical and orthodontic), the valuation of the necessary space to move the impacted tooth in the normal position and the biomechanical approach for anchorage, avoiding prosthetic/implants replacement. Results The therapy of an impacted maxillary incisor due to trauma requires a multidisciplinary approach: orthodontic, surgical, endodontic and periodontal considerations are essential for successful treatment. Conclusions Surgical exposure and orthodontic traction is the treatment most often used in case of posttraumatic impacted incisor: this technique in fact can lead to suitable results at the periodontal, occlusal and esthetics levels at an early stage and more definitively than with other treatment options.

Paoloni, Valeria; Pavoni, Chiara; Mucedero, Manuela; Bollero, Patrizio; Lagana, Giuseppina; Cozza, Paola

2013-01-01

72

Apexogenesis and revascularization treatment procedures for two traumatized immature permanent maxillary incisors: a case report  

PubMed Central

Traumatic injuries to an immature permanent tooth may result in cessation of dentin deposition and root maturation. Endodontic treatment is often complicated in premature tooth with an uncertain prognosis. This article describes successful treatment of two traumatized maxillary central incisors with complicated crown fracture three months after trauma. The radiographic examination showed immature roots in maxillary central incisors of a 9-year-old boy with a radiolucent lesion adjacent to the right central incisor. Apexogenesis was performed for the left central incisor and revascularization treatment was considered for the right one. In 18-month clinical and radiographic follow-up both teeth were asymptomatic, roots continued to develop, and periapical radiolucency of the right central incisor healed. Considering the root development of these contralateral teeth it can be concluded that revascularization is an appropriate treatment method in immature necrotic teeth.

Forghani, Maryam; Maghsoudlou, Amir

2013-01-01

73

Upper incisors' positions after extraction.  

PubMed

The aim of this research was to verify the amount of horizontal and vertical movement and incisor inclination of upper incisors and correlate these with Edgewise and Alexander brackets use and the presence of overbite during anterior retraction in sliding mechanics. The sample was composed of 40 adult patients divided into 2 groups, treated with Edgewise and Alexander brackets (20 each) subdivided in 2 groups (10 each), according to the presence or absence of deep bite. Treatment consisted of 4 extraction cases with sliding mechanics with the 2 different brackets. Pre- and post-treatment cephalograms were measured and the values of interest submitted to descriptive statistical analysis, ANOVA at 5%, the Tukey test and Pearson's correlation. Upper incisor retraction was not related to the brackets used nor to the presence of deep bite, though lingual tipping was greater when Edgewise brackets were used and deep bite was absent. No statistically significant differences in upper incisor vertical movements were observed and no correlation was determined between upper incisor intrusion and lower incisor labial tipping in overbite correction or in upper incisor retraction and lower incisor labial tipping for overjet correction. Bracket prescription and its interaction with deep bite were significant and Edgewise brackets without deep bite showed the worst inclination control. It was concluded that bracket prescriptions are important to increase control of sliding mechanics. PMID:24812742

Werneck, Eduardo César; Mattos, Fernanda Silva; Cotrim-Ferreira, Flávio Augusto; Prado, Renata Falchete; Silva, Márcio Garcia; Araújo, Adriano Marotta

2014-01-01

74

The influence of varying maxillary lateral incisor dimensions on perceived smile aesthetics  

Microsoft Academic Search

Objective The aim of this study was to determine the influence of varying the dimensions of the maxillary lateral incisors on perceived smile aesthetics.Design Clinical study.Setting Postgraduate dental teaching hospital.Methods A photograph of a female smile displaying only the lips and teeth was digitally altered. First, the width of the maxillary lateral incisors, in proportion to the central incisor, was

S. M. N. Bukhary; D. S. Gill; D. R. Moles; C. J. Tredwin

2007-01-01

75

Orthodontic retraction of autotransplanted premolar to replace ankylosed maxillary incisor with replacement resorption.  

PubMed

This case report describes the successful treatment of an adult with lip protrusion and a previously traumatized maxillary central incisor that had experienced replacement root resorption. An extracted premolar was transplanted into the incisor space and retracted orthodontically. Autotransplantation was successful with complete root formation and, combined with orthodontic treatment, provided a satisfying esthetic outcome. PMID:24703290

Choi, Yoon Jeong; Shin, Sujung; Kim, Kyung-Ho; Chung, Chooryung J

2014-04-01

76

Human mandibular incisors from the late Middle Pleistocene locality of Hoedjiespunt 1, South Africa  

Microsoft Academic Search

The Hoedjiespunt 1 locality is an archaeological and palaeontological site located on the Hoedjiespunt Peninsula at Saldanha Bay, South Africa. In 1996 two human teeth, a left central mandibular incisor and a left lateral mandibular incisor, were discovered during excavations in the late Middle Pleistocene palaeontological layers. These teeth are described and are found to belong to a single subadult

Deano D. Stynder; Jacopo Moggi-Cecchi; Lee R. Berger; John E. Parkington

2001-01-01

77

Middle Paleolithic human deciduous incisor from Khudji, Tajikistan  

Microsoft Academic Search

In 1997 a human mandibular second deciduous incisor was discovered during excavations at the central Asian Middle Paleolithic site of Khudji, Tajikistan. The specimen was associated with a late Middle Paleolithic assemblage in a minimally disturbed cultural layer. The specimen is average in size for Late Pleistocene archaic human di2s and differs from many late archaic human di2s in having

Erik Trinkaus; Vadim A. Ranov; Stanislav Lauklin

2000-01-01

78

Inverted Impacted Primary Maxillary Incisors: A Case Report  

PubMed Central

Tooth impaction rarely occurs in primary dentition. Most of the primary teeth impactions are seen in second molars. The purpose of this article is to present a 4-year-old girl with bilateral impaction of inverted primary maxillary central incisors which trauma had displaced their tooth germ before erupting.

Seraj, B.; Ghadimi, S.; Mighani, G.; Zare, H.; Rabbani, M.

2012-01-01

79

Lip-to-incisor relationship and postorthodontic long-term stability of cover-bite treatment  

Microsoft Academic Search

OBJECTIVE: To investigate the impact of a persisting high lip line and other potential relapse-inducing factors on long-term stability of orthodontic correction of retroinclined maxillary central incisors. MATERIALS AND METHODS: Thirty-one cover-bite (\\

Bernd G. Lapatki; Dirk Baustert; J. Schulte-Monting; Sibylle Frucht; Irmtrud E. Jonas

2006-01-01

80

A new type of dental anomaly: molar-incisor malformation (MIM).  

PubMed

A molar-incisor malformation (MIM) is a newly discovered type of dental anomaly of the permanent first molars, deciduous second molars, and permanent maxillary central incisors. MIM anomalies of the permanent first molars and deciduous second molars may include normal crowns with a constricted cervical region and thin, narrow, and short roots, whereas the affected maxillary central incisors may exhibit a hypoplastic enamel notch near the cervical third of the clinical crown. Although the etiology of MIM remains to be determined, it is thought to be attributable to an epigenetic factor linked to brain- and central nervous system-related systemic diseases at around age 1 to 2 years. MIM teeth are associated with clinical problems such as impaction, early exfoliation, space loss, spontaneous pain, periapical abscess, and poor incisor esthetics. Children with MIM teeth should be observed closely with respect to their medical history, and dentists should formulate a wider-ranging treatment plan. PMID:24908600

Lee, Hyo-Seol; Kim, Soo-Hyun; Kim, Seong-Oh; Lee, Jae-Ho; Choi, Hyung-Jun; Jung, Han-Sung; Song, Je Seon

2014-07-01

81

Missing upper lateral incisors: orthodontic considerations in young patients.  

PubMed

Missing lateral incisors are usually discovered by age 9 when general orthodontic treatment needs are becoming apparent. Whether to close, open or maintain a space for a missing lateral incisor is an orthodontic decision that needs to fit within a total plan of dental management. Factors to consider include:- Skeletal base relationship, severity of crowding, overjet, overbite, position into which the canine erupts, crown sizes, crown shapes, crown colours, gingival contours, gingival display on smiling, patient and parent attitude toward options, availability of appropriate prosthetic services, time delay before effecting "final" prosthetic treatment, space and bone required for implant fixtures and financial and biological costs. PMID:11709923

Wexler, G

2000-10-01

82

Aggressive dentigerous cyst with ectopic central incisor.  

PubMed

Summary Dentigerous cysts form from accumulation of fluid between reduced enamel epithelium and the crown of an unerupted tooth. They cause several difficulties such as swelling, non-eruption of the involved teeth, and displacement of adjacent teeth, and thus require early detection and prompt treatment. Treatment ranges from marsupialisation to enucleation. Enucleation is rarely used in children compared with marsupialisation. This paper discusses successful use of enucleation for treating a dentigerous cyst and explains the need for such a radical procedure. PMID:24913076

Jayam, Cheranjeevi; Mitra, Malay; Bandlapalli, Anila; Jana, Biswanath

2014-01-01

83

Five mandibular incisors: an autosomal recessive trait?  

Microsoft Academic Search

A fifth mandibular incisor is a eumorphic supernumerary tooth and has rarely been described in the medical literature. We report here a large Lebanese consanguineous family where four individuals displayed five incisors in the anterior mandible. Such familial observation has not been previously described. The possibility of an autosomal recessive inheritance for this nonsyndromic trait is discussed.

A Cassia; A Feki; A Megarbane; S El-Toum

2004-01-01

84

Revascularization of immature permanent incisors after severe extrusive luxation injury.  

PubMed

Pulp necrosis is an uncommon sequel to extrusive luxation in immature teeth with incomplete apical closure. In this report, we describe the management of severely extruded immature maxillary incisors and the outcome of revascularization to treat subsequent pulp necrosis. An 8.5-Year-old boy with severe dentoalveolar trauma to the anterior maxillary region as a result of a fall was provided emergency treatment consisting of reduction of the dislodged labial cortical bone and repositioning of the central incisors, which had suffered extrusive luxation. When he presented with spontaneous pain involving the traumatized incisors a week later, the teeth were treated via a revascularization protocol using sodium hypochlorite irrigation followed by 3 weeks of intracanal calcium hydroxide, then a coronal seal of mineral trioxide aggregate and resin composite. Complete periradicular healing was observed after 3 Months, followed by progressive thickening of the root walls and apical closure. Follow-up observations confirmed the efficacy of the regenerative treatment as a viable alternative to conventional apexification in endodontically involved, traumatized immature teeth. PMID:22322021

Cehreli, Zafer C; Sara, Sezgi; Aksoy, Burak

2012-01-01

85

Revascularization of immature permanent incisors after severe extrusive luxation injury.  

PubMed

Pulp necrosis is an uncommon sequel to extrusive luxation in immature teeth with incomplete apical closure. In this report, we describe the management of severely extruded immature maxillary incisors and the outcome of revascularization to treat subsequent pulp necrosis. An 8.5-year-old boy with severe dentoalveolar trauma to the anterior maxillary region as a result of a fall was provided emergency treatment consisting of reduction of the dislodged labial cortical bone and repositioning of the central incisors, which had suffered extrusive luxation. When he presented with spontaneous pain involving the traumatized incisors a week later, the teeth were treated via a revascularization protocol using sodium hypochlorite irrigation followed by 3 weeks of intracanal calcium hydroxide, then a coronal seal of mineral trioxide aggregate and resin composite. Complete periradicular healing was observed after 3 months, followed by progressive thickening of the root walls and apical closure. Follow-up observations confirmed the efficacy of the regenerative treatment as a viable alternative to conventional apexification in endodontically involved, traumatized immature teeth. PMID:22916525

Cehreli, Zafer C; Sara, Sezgi; Aksoy, Burak

2012-07-01

86

Quantum-walk-based search and centrality  

SciTech Connect

We study the discrete-time quantum-walk-based search for a marked vertex on a graph. By considering various structures in which not all vertices are equivalent, we investigate the relationship between the successful search probability and the position of the marked vertex, in particular, its centrality. We find that the maximum value of the search probability does not necessarily increase as the marked vertex becomes more central, and we investigate an interesting relationship between the frequency of the successful search probability and the centrality of the marked vertex.

Berry, Scott D.; Wang, Jingbo B. [School of Physics, The University of Western Australia, Perth, WA 6009 (Australia)

2010-10-15

87

Dynamics-based centrality for directed networks.  

PubMed

Determining the relative importance of nodes in directed networks is important in, for example, ranking websites, publications, and sports teams, and for understanding signal flows in systems biology. A prevailing centrality measure in this respect is the PageRank. In this work, we focus on another class of centrality derived from the Laplacian of the network. We extend the Laplacian-based centrality, which has mainly been applied to strongly connected networks, to the case of general directed networks such that we can quantitatively compare arbitrary nodes. Toward this end, we adopt the idea used in the PageRank to introduce global connectivity between all the pairs of nodes with a certain strength. Numerical simulations are carried out on some networks. We also offer interpretations of the Laplacian-based centrality for general directed networks in terms of various dynamical and structural properties of networks. Importantly, the Laplacian-based centrality defined as the stationary density of the continuous-time random walk with random jumps is shown to be equivalent to the absorption probability of the random walk with sinks at each node but without random jumps. Similarly, the proposed centrality represents the importance of nodes in dynamics on the original network supplied with sinks but not with random jumps. PMID:21230545

Masuda, Naoki; Kori, Hiroshi

2010-11-01

88

Dynamics-based centrality for directed networks  

NASA Astrophysics Data System (ADS)

Determining the relative importance of nodes in directed networks is important in, for example, ranking websites, publications, and sports teams, and for understanding signal flows in systems biology. A prevailing centrality measure in this respect is the PageRank. In this work, we focus on another class of centrality derived from the Laplacian of the network. We extend the Laplacian-based centrality, which has mainly been applied to strongly connected networks, to the case of general directed networks such that we can quantitatively compare arbitrary nodes. Toward this end, we adopt the idea used in the PageRank to introduce global connectivity between all the pairs of nodes with a certain strength. Numerical simulations are carried out on some networks. We also offer interpretations of the Laplacian-based centrality for general directed networks in terms of various dynamical and structural properties of networks. Importantly, the Laplacian-based centrality defined as the stationary density of the continuous-time random walk with random jumps is shown to be equivalent to the absorption probability of the random walk with sinks at each node but without random jumps. Similarly, the proposed centrality represents the importance of nodes in dynamics on the original network supplied with sinks but not with random jumps.

Masuda, Naoki; Kori, Hiroshi

2010-11-01

89

Impacted maxillary incisors: diagnosis and predictive measurements  

PubMed Central

Summary Background When the incisors do not erupt at the expected time, it is crucial for the clinician to determine the etiology and formulate an appropriate treatment plan. Aim The aim of this report is to provide useful information for immediate diagnosis and management of impacted maxillary incisors using the interceptive treatment: removal of obstacles and rapid maxillary expansion (RME). Design An accurate diagnosis may be obtained with clinical and radiographic exam such as panoramic radiograph, computerized tomography (CT) and cone beam computerized tomography (CBCT). It’s important to know the predictive measurements of eruption evaluated on panoramic radiograph: distance from the occlusal plane, maturity, angulation and vertical position of the unerupted incisors. Early diagnosis is important and interceptive orthodontic treatment, such as removal of obstacles and orthopedic rapid maxillary expansion (RME), may correct disturbances during the eruption through recovering space for the incisors and improving the intraosseus position of delayed teeth. Results RME treatment following the surgical removal of the obstacle to the eruption of maxillary incisors leads to an improvement of the intraosseus position of the tooth. Conclusions The angulation and the vertical position of the delayed tooth appear to be important in trying to predict eruption. The improvement of the intraosseus position of the unerupted incisor, obtained by removal of the odontoma and rapid maxillary expansion, permits a conservative surgery and the achievement of an excellent esthetics and periodontal result.

Pavoni, Chiara; Mucedero, Manuela; Lagana, Giuseppina; Paoloni, Valeria; Cozza, Paola

2012-01-01

90

Signaling by FGFR2b controls the regenerative capacity of adult mouse incisors  

PubMed Central

Rodent incisors regenerate throughout the lifetime of the animal owing to the presence of epithelial and mesenchymal stem cells in the proximal region of the tooth. Enamel, the hardest component of the tooth, is continuously deposited by stem cell-derived ameloblasts exclusively on the labial, or outer, surface of the tooth. The epithelial stem cells that are the ameloblast progenitors reside in structures called cervical loops at the base of the incisors. Previous studies have suggested that FGF10, acting mainly through fibroblast growth factor receptor 2b (FGFR2b), is crucial for development of the epithelial stem cell population in mouse incisors. To explore the role of FGFR2b signaling during development and adult life, we used an rtTA transactivator/tetracycline promoter approach that allows inducible and reversible attenuation of FGFR2b signaling. Downregulation of FGFR2b signaling during embryonic stages led to abnormal development of the labial cervical loop and of the inner enamel epithelial layer. In addition, postnatal attenuation of signaling resulted in impaired incisor growth, characterized by failure of enamel formation and degradation of the incisors. At a cellular level, these changes were accompanied by decreased proliferation of the transit-amplifying cells that are progenitors of the ameloblasts. Upon release of the signaling blockade, the incisors resumed growth and reformed an enamel layer, demonstrating that survival of the stem cells was not compromised by transient postnatal attenuation of FGFR2b signaling. Taken together, our results demonstrate that FGFR2b signaling regulates both the establishment of the incisor stem cell niches in the embryo and the regenerative capacity of incisors in the adult.

Parsa, Sara; Kuremoto, Koh-ichi; Seidel, Kerstin; Tabatabai, Reza; MacKenzie, BreAnne; Yamaza, Takayoshi; Akiyama, Kentaro; Branch, Jonathan; Koh, Chester J.; Alam, Denise Al; Klein, Ophir D.; Bellusci, Saverio

2010-01-01

91

Centralized versus Decentralized Conversation-based Orchestrations  

Microsoft Academic Search

There has been a great deal of interest in recent years in the use of service oriented approach and relevant standards to implement business processes. Following the concepts of workflow-based process management, the major focus has been on service composition. Not surprisingly, this default composition approach suffers from the limitations of centralized workflow management. It is well recognized that a

Ustun Yildiz; Claude Godart

2007-01-01

92

Mandibular incisor alignment and dental arch changes 1 year after extraction of deciduous canines.  

PubMed

This study investigated the early effects on mandibular incisor irregularity and rotation together with dental arch dimensions of the extraction of four deciduous canines. Children, during early mixed dentition, were randomized into one extraction (n = 32) and one control (n = 41) group. Dental casts from baseline (T0) and 1 year follow-up (T1) were used to evaluate changes in the irregularity index and in mandibular incisor rotation, dental arch dimensions, overjet, and overbite. Median mandibular incisor irregularity decreased over time, significantly more in the extraction than the control group (1.2 versus 0.7 mm; P < 0.01), with wide ranges in both groups. Rotational changes greater than 10 degrees for lateral incisors were twice as common in the extraction group (42 versus 20 per cent; P < 0.01). Central incisors displayed only minor changes in both groups. The correlation between changes in irregularity index and changes in incisor rotation was weak in both groups (r(s) < 0.3 not significant). According to professional assessment of overall alignment, 84 per cent in the extraction group versus 34 per cent in the control group (P < 0.001) improved from T0 to T1. A significant decrease in maxillary and mandibular arch length and circumference from T0 to T1 was recorded in the extraction group (1.3, 1.1 mm and 2.4, 2.0 mm, respectively; P < 0.001), while arch dimensions were preserved in the control group. To conclude, 1 year after extraction of the deciduous canines, small improvements in mandibular incisor alignment were seen, together with reduced arch dimensions. Little's index underestimated malalignment related to tooth rotation. PMID:21345928

Sjögren, Anders; Arnrup, Kristina; Lennartsson, Bertil; Huggare, Jan

2012-10-01

93

An in vitro comparison of three endodontic techniques for primary incisors  

Microsoft Academic Search

2 Comparison of these techniques has not been tested under controlled conditions. In this study, the effective- ness of the incremental technique will be tested and com- pared with the lentulo spiral and pressure syringe tech- niques. Methods and materials Fifty-four extracted primary maxillary central incisors with some incisal edge intact as a reference point and no more than 25%

Moutaz B. Dandashi; Mamoun M. Nazif; Margaret A. Elliott; Lawrence G. Schneider

1993-01-01

94

Assessment of open and incomplete bite correction by incisor overlap and optical density of polyvinyl siloxane bite registration.  

PubMed

Open bite (OB) is a generalized term, which could incorporate subgroups that react differently to vertical correction. The objectives of the present study were to detect vertical treatment changes in incomplete bite (IB: inter-incisor overlap with no lower incisor contact with teeth or palate) and OB (no inter-incisor overlap) groups compared with a complete bite (CB: inter-incisor overlap with full lower incisor contact with teeth or palate) control group, to evaluate treatment response of the central and lateral incisors, and to study the vertico-sagittal interaction. Dental casts were taken at three time points, pre-treatment, post-treatment, and after one year of retention, from 54 Class II patients (22 males and 32 females with a mean age of 11 years 6 months) divided into three groups: CB (n = 21), IB (n = 18) and OB (n = 15). Measurements included incisor overlap (mm) and optical density (OD/mm2) of occlusal bite registration made of polyvinl siloxane. Both CB and IB groups demonstrated post-retention bite opening. However, bite opening in the CB group was three times greater than that in the IB group (e.g. lower lateral = -1.42 mm, 118 OD/mm2 versus -0.40 mm, 107 OD/mm2). Conversely, the OB group showed a significant (P < 0.001) bite closure (e.g. lower lateral = 1.30 mm, -377 OD/mm2). Overjet changes affected OD measurements, causing diversity in OD and millimetric measurements of the lateral incisors in the IB group. In conclusion, the OB group demonstrated a significant stable vertical correction; a post-treatment non-contact inter-incisor relationship was determined by a vertico-sagittal relapse; and full compensation of an IB was not possible. PMID:16267127

Shpack, Nir; Einy, Shmuel; Beni, Lea; Vardimon, Alexander D

2006-04-01

95

Strong Genetic Control of Emergence of Human Primary Incisors  

Microsoft Academic Search

Our understanding of tooth eruption in humans remains incomplete. We hypothesized that genetic factors contribute significantly to phenotypic variation in the emergence of primary incisors. We applied model-fitting to data from Australian twins to quantify contributions of genetic and environmental factors to variation in timing of the emergence of human primary incisors. There were no significant differences in incisor emergence

T. E. Hughes; M. R. Bockmann; K. Seow; T. Gotjamanos; N. Gully; L. C. Richards; G. C. Townsend

2010-01-01

96

Strong Genetic Control of Emergence of Human Primary Incisors  

Microsoft Academic Search

Our understanding of tooth eruption in humans remains incomplete. We hypothesized that genetic factors contribute significantly to phenotypic variation in the emergence of primary incisors. We applied model-fitting to data from Australian twins to quantify contributions of genetic and environmental factors to variation in timing of the emergence of human primary incisors. There were no significant differences in incisor emergence

Toby E Hughes; Michelle R Bockmann; Kim Seow; Theo Gotjamanos; Neville Gully; Lindsay C Richards; Grant C Townsend

2007-01-01

97

[Socket healing after rat mandibular incisor extraction].  

PubMed

Prosthodontic treatment is difficult if the alveolar ridge is low or thin. To develop a method for alveolar ridge preservation after tooth extraction, we need an experimental model of a small animal, in which we can analyze the socket healing easily and quantitatively. The purpose of the present study was to establish such an experimental model. Ten weeks old male rats of Wistar strain were used. The edge of the right mandibular incisor was cut every three days three times and the incisor was extracted at three days after the final cut. The animals were sacrificed 0, 1, 2, 4, 8, 12 weeks after the extraction and the mandibles were dissected out. The length of the alveolar bone was measured on soft X-ray photographs and bone mineral content was measured with a dual energy X-ray absorptiometer (DEXA). Then, transverse sections of the alveolar bone were prepared. Periodic three-times cutting of the edge of the mandibular incisor made the extraction easy. Quantitative analyses of new bone formation in the socket and the resorption of the alveolar bone were possible with soft X-ray photography and DEXA. The histological findings corresponded well with the data from the soft X-ray photos and DEXA measurements. The present results demonstrated the possibility of simple and quantitative analyses of socket healing after the extraction of rat mandibular incisors. This experimental model would be useful for developing a method to prevent atrophy of the alveolar ridge after tooth extraction. PMID:15856778

Sato, Daisuke

2005-03-01

98

Surface-based inversions above central Greenland  

NASA Astrophysics Data System (ADS)

Surface-based temperature inversions (SBIs) are studied at Summit Station in central Greenland during the period spanning July 2010 to May 2012. The frequency and intensity of SBI are examined using microwave radiometer (MWR) temperature retrievals, radiosonde profiles, and near-surface meteorological data. Using the MWRs' high temporal resolution, the diurnal, monthly, and annual cycles are investigated. Monthly mean values in SBI occurrence and intensity show that surface-based inversions are prevalent in the winter with decreasing values in the summer months. A case study on 20 February 2011 suggests that factors other than solar elevation angle influence the intensity of surface-based inversions. An increase in liquid water path corresponds to a decrease in SBI intensity, suggesting that liquid-bearing clouds, especially within the lowest 1 km, are associated with weaker surface-based inversions.

Miller, N. B.; Turner, D. D.; Bennartz, R.; Shupe, M. D.; Kulie, M. S.; Cadeddu, M. P.; Walden, Von P.

2013-01-01

99

Emerging therapies for the management of traumatized immature permanent incisors.  

PubMed

Early loss of immature permanent teeth due to pulpal necrosis secondary to trauma can have dire consequences for a child's growth and development. The treatment alternatives include surgical endodontics, traditional calcium hydroxide apexification, and mineral trioxide aggregate (MTA) apexification. These options pose potential complications, including: arrest of root development; weakened dentinal walls; and increased potential for fracture. Revascularization of the dentin-pulp complex is a new approach that involves disinfecting the root canal system followed by tissue repair and regeneration while allowing for continued root development and thickening of the lateral dentinal walls through deposition of new hard tissue. The purpose of this report was to present the revascularization of an immature permanent maxillary central incisor that had evidence of external root resorption. Six months later, internal bleaching was performed to remove cervical discoloration from the triple antibiotic paste. At 18 months, the tooth remained vital and had evidence of continued root development. PMID:22353461

Miller, Elizabeth K; Lee, Jessica Y; Tawil, Peter Z; Teixeira, Fabricio B; Vann, William F

2012-01-01

100

Age-related morphometry of equine incisors.  

PubMed

In the present study the age-related morphological characteristics of 948 equine incisors were investigated. After extraction, total incisival length and root length were measured at the vestibular side of the teeth. Equine incisors reach their maximal length 2-3 years after eruption. Notwithstanding severe occlusal wear, this maximal length is maintained during most of the horses' life due to prolonged root formation. Root formation, at the rate of 2.5 mm per year, starts at the age of 5-6 years and continues until the age of 17. As the root of the incisor develops, its apical foramen narrows and changes position. In young horses the apical foramen is situated at the apex of the tooth, whereas in older individuals it is located at the mesial, distal, or lingual side of the tooth at a distance of 5-15 mm from the dental apex. In horses aged over 20 years apical foramina are still present. Radiographic imaging is a good method with which to obtain reliable information concerning the total incisival length and the size and position of the apical foramen. PMID:10638301

Muylle, S; Simoens, P; Lauwers, H

1999-12-01

101

First records of talon cusps on baboon maxillary incisors argue for standardizing terminology and prompt a hypothesis of their formation.  

PubMed

Dental characters can provide vital clues for understanding intra- and intertaxonomic morphological variation and its underlying genetic and environmental components. However, the unambiguous identification of particular traits and their comparative study is often confounded by lack of consistent terminology in the relevant literature. This difficulty is exacerbated when the etiologies are not completely understood, as is the case with talon cusps. To date, research on talon cusps has focused on modern humans. In many instances, descriptions of talon cusps appear in clinical case studies focusing on their treatment and removal. What is lacking in those discussions, though, is a comparative framework, in which the occurrence of talon cusps in nonhuman primates, and possibly other mammals, is established and understood. Here, we report on a taloned upper central incisor of a wild baboon (Papio hamadryas ursinus) from South Africa. The anomalous incisor of this individual includes an exaggerated accessory cusp diagnosed as a Type II talon. Microcomputed tomographic and radiographic analyses show that the taloned cusp possesses enamel, dentin, and pulp. In addition, we identified an unclassifiable talon cusp on a central maxillary incisor of a baboon skull housed in the Smithsonian Institution's Natural History Museum collection. Our observations of talon cusps on baboon incisors demonstrate that, with regard to this phenomenon, systematic study of nonhuman primates is much needed, along with a consistent use of terminology in the anatomical and anthropological literature. Finally, we present a hypothesis of the formation of talon cusps on mammalian incisors. PMID:24173685

Heaton, Jason L; Pickering, Travis Rayne

2013-12-01

102

MTA resorption and periradicular healing in an open-apex incisor: A case report  

PubMed Central

This case report describes the periradicular healing and resorption of an unintentional extrusion of mineral trioxide aggregate (MTA) in an open-apex central incisor. A 22-year old female with a symptomatic open-apex right maxillary central incisor associated with a periradicular lesion was referred for evaluation and treatment. After chemomechanical debridement, the apical third of the root canal was filled with MTA to create an apical plug. Postoperative radiographs showed the extrusion of MTA into the periradicular lesion. The tooth was then restored with a post and crown. At the 2-year follow-up, the tooth was asymptomatic and radiographs revealed complete healing of the periradicular area. At the 7-year follow-up, complete resorption of the extruded MTA was evident. The results of this case study indicate that complete resorption of extruded MTA is possible in the long term; however, the extrusion of MTA in open-apex tooth should still be avoided.

Asgary, Saeed; Ehsani, Sara

2011-01-01

103

Morphological characterization of rat incisor fluorotic lesions  

Microsoft Academic Search

The morphological characterization of fluorotic rat incisor enamel was carried out. Experimental adult animals received drinking water with 45mg F\\/L of fluoride, and the control group received distilled water. Fluoride concentrations found in the control and fluorosis groups were 0.04 and 0.09?g\\/mL (plasma), 0.26 and 0.66?g\\/mg (whole tibia), and 0.24 and 2.3?g\\/mg (tibia surface), with P?0.001 for all comparisons between

Regina Aparecida Saiani; Isabel Maria Porto; Elcio Marcantonio Junior; Jaime Aparecido Cury; Frederico Barbosa de Sousa; Raquel Fernanda Gerlach

2009-01-01

104

Intracoronal bleaching of nonvital discolored mandibular incisors.  

PubMed

Intracoronal bleaching of pulpless discolored mandibular incisors is a valuable treatment modality currently disregarded by many clinicians because of the potentially disastrous consequence of cervical resorption. A patient-administered, intracoronal carbamide peroxide bleaching technique is described. This modified, walking bleaching method minimizes the risks because treatment time is reduced to days, as opposed to weeks with the original walking bleaching protocol, the concentration of the hydrogen peroxide is markedly reduced, and residual hydrogen peroxide is completely eliminated with the use of catalase prior to the definitive restoration. PMID:17402632

Liebenberg, William H

2007-01-01

105

Characterization of Progenitor Cells in Pulps of Murine Incisors  

Microsoft Academic Search

The continuous growth of rodent incisors requires the presence of stem cells capable of generating ameloblasts and odontoblasts. While epithelial stem cells giving rise to ameloblasts have been well-characterized, cells giving rise to the odontoblasts in incisors have not been fully characterized. The goal of this study was to gain insight into the potential population in dental pulps of unerupted

A. Balic; M. Mina

2010-01-01

106

Morphological characterization of rat incisor fluorotic lesions.  

PubMed

The morphological characterization of fluorotic rat incisor enamel was carried out. Experimental adult animals received drinking water with 45 mg F/L of fluoride, and the control group received distilled water. Fluoride concentrations found in the control and fluorosis groups were 0.04 and 0.09 microg/mL (plasma), 0.26 and 0.66 microg/mg (whole tibia), and 0.24 and 2.3 microg/mg (tibia surface), with P < or = 0.001 for all comparisons between the groups. A succession of white and pigmented bands was observed in the fluorotic rat incisors. Under polarizing light microscopy, cross-sections of superficial areas corresponding to the white bands (from the surface to approximately 20 microm) showed high positive birefringence. These fluorotic lesions also exhibited the lowest resistance to superficial acid etching. No morphological differences in inner enamel were seen under scanning electron microscopy. In fluorotic enamel, only the surface layer related to the white areas presented lower birefringence compared with the enamel of control teeth and the surface layer of the pigmented areas (normal ones) of fluorotic teeth. In conclusion, the white bands of fluorotic rat enamel represent hypomineralized superficial areas and are not subsurface lesions. The detailed description of these lesions is important to understand dental fluorosis. PMID:19781688

Saiani, Regina Aparecida; Porto, Isabel Maria; Marcantonio Junior, Elcio; Cury, Jaime Aparecido; de Sousa, Frederico Barbosa; Gerlach, Raquel Fernanda

2009-11-01

107

U.S. Bases in Central Asia.  

National Technical Information Service (NTIS)

The Central Asian nations of Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan have offered varying degrees of assistance to U.S. global war on terrorism (GWOT). This paper outlines the nature of their responses to the U.S. campaign and det...

S. L. Clark-Sestak

2003-01-01

108

An Identification Key to Rodent Prey in Owl Pellets from the Northwestern and Southeastern United States: Employing Incisor Size to Distinguish among Genera  

ERIC Educational Resources Information Center

We present an identification key to the common rodent prey found in owl pellets from the Northwestern (NW) and Southeastern (SE) United States that is based on differences in incisor size (arc diameter) among genera.

Hager, Stephen B.; Cosentino, Bradley J.

2006-01-01

109

Cone beam-computed topographic evaluation of a central incisor with an open apex and a failed root canal treatment using one-step apexification with Biodentine(TM): A case report  

PubMed Central

A symptomatic endodontically treated immature tooth with periapical pathology presents multiple challenges to the clinician. Owing to incomplete root formation, gutta percha removal has to be done carefully without further damaging the periapical tissue or pushing the obturating material beyond the apex. Nonsurgical approach toward treating such a tooth would necessitate the creation of an apical barrier followed by conventional root canal treatment. Current literature suggests one-step apexification with mineral trioxide aggregate (MTA), with an apical matrix as the treatment of choice. A new calcium silicate-based cement also called as dentine substitute by the manufacturers with good handling properties has been introduced recently by the trade name Biodentine™ (Septodont, St. Maurdes Fossés, France). This case report presents management of a secondary endodontic case with an open apex treated with the concept of ‘lesion sterilization and tissue repair (LSTR)’ using triantibiotic paste and Biodentine™ for apical barrier formation. A 12-month follow up with cone beam-computed topography (CBCT) exhibited progressive involution of periapical radiolucency with indications of good healing of the periapical tissues and absence of clinical symptoms.

Sinha, Nidhi; Singh, Bijay; Patil, Santosh

2014-01-01

110

An incisor plaque model in rats.  

PubMed

An in vivo model for studying plaque accumulation in rats has been described. This model investigates plaque formation on the mandibular incisors in animals which have been found to be rapid plaque-formers during a pre-test period. The accessibility of these tooth surfaces permits the removal of plaque prior to initiation of tests, the use of test groups balanced on the basis of plaque-forming potential, and interim assessments of plaque formation throughout the test period. In addition, baseline plaque scores of near zero can be attained, thereby permitting investigations of the impact of experimental measures on plaque formation. Moreover, the model permits intermittent plaque assessments throughout the test period. This model was found to have adequate sensitivity to distinguish effects between antimicrobial agents known to differ in their clinical activity and to detect differences between varying concentrations of the same agent. PMID:6582077

Schemehorn, B R; McDonald, J L; Stookey, G K; Park, K K

1984-01-01

111

The Adaptive Significance of Enamel Loss in the Mandibular Incisors of Cercopithecine Primates (Mammalia: Cercopithecidae): A Finite Element Modelling Study  

PubMed Central

In several primate groups enamel is reduced or absent from the lingual (tongue) side of the mandibular incisor crowns akin to other placental and marsupial mammalian groups such as rodents, lagomorphs and wombats. Here we investigate the presumed adaptation of crowns with unilateral enamel to the incision of tough foods in cercopithecines, an Old World monkey subfamily, using a simulation approach. We developed and validated a finite element model of the lower central incisor of the rhesus macaque (Macaca mulatta) with labial enamel only to compute three-dimensional displacements and maximum principal stresses on the crown subjected to compressive loads varying in orientation. Moreover, we developed a model of a macaque incisor with enamel present on both labial and lingual aspects, thus resembling the ancestral condition found in the sister taxon, the leaf-eating colobines. The results showed that, concomitant with experimental results, the cercopithecine crown with unilateral enamel bends predominantly towards the inside of the mouth, while displacements decreased when both labial and lingual enamel are present. Importantly, the cercopithecine incisor crown experienced lower maximum principal stress on the lingual side compared to the incisor with enamel on the lingual and labial aspects under non-axial loads directed either towards the inside or outside of the mouth. These findings suggest that cercopithecine mandibular incisors are adapted to a wide range of ingestive behaviours compared to colobines. We conclude that the evolutionary loss of lingual enamel in cercopithecines has conferred a safeguard against crown failure under a loading regime assumed for the ingestion (peeling, scraping) of tough-skinned fruits.

Kupczik, Kornelius; Lev-Tov Chattah, Netta

2014-01-01

112

Surgical treatment of an unerupted supernumerary tooth attached to an unerupted permanent incisor  

Microsoft Academic Search

An unerupted supernumerary tooth was attached to the root surface of an unerupted permanent lateral incisor. It was necessary to remove both the supernumerary and the permanent lateral incisor as a single unit. The permanent lateral incisor was separated from the supernumerary and placed back into the original developmental crypt. The replanted lateral incisor erupted normally one year later.

Mark V. Barren

1983-01-01

113

Management of internal resorption of central incisor using hybrid technique.  

PubMed

Internal inflammatory root resorption is characterised by progressive destruction of intraradicular dentin and dentinal tubules along the root canal wall. A number of theories have been proposed as a possible cause for internal resorption. It is usually asymptomatic and detected during routine radiographic investigations. Prompt diagnosis and early management of such defects is essential to maintain the integrity of the tooth. Non-surgical and surgical methods are the two main strategies involved in the management of internal resorption. The non-surgical method is usually preferred, but in cases of extensive resorption with external root perforation, surgical intervention has been advocated. The present case illustrates repair of perforating internal resorption by hybrid method, using mineral trioxide aggregate and gutta-percha, following surgical exposure. After a 10-month follow-up, no clinical and radiographic abnormalities were observed. Additionally, there was also marked reduction in periodontal pocket depth. PMID:24473420

Gayathri, Prabakaran; Pandey, Ramesh Kumar; Jain, Eesha

2014-01-01

114

A report of an impacted primary maxillary central incisor tooth.  

PubMed

Primary tooth impaction is a rare phenomenon when compared to permanent teeth impaction. The purpose of this report is to present a 5-year-old Chinese girl who exhibited impaction of tooth 51, its unusual consequence on the permanent successor tooth and its comprehensive management. Her parents revealed that at 6 months of age, the patient had fallen from her bed and struck her face on the floor; however, there were no teeth present in the oral cavity. The intraoral examinations identified a bony-like projection on the buccal aspect of the alveolus in the 51 region. Radiographic examination revealed that tooth 51 exhibited an unfavourable orientation, with the crown directed towards the palate. Therefore, the impacted tooth 51 was surgically removed, and two years later tooth 11 erupted into the oral cavity with an indentation on its incisal aspect, which resembled the crown of the primary teeth, thus giving the appearance of a tooth within a tooth or 'dens in dente'. Subsequently, enameloplasty and composite resin build-up was performed on tooth 11 for aesthetic reasons. It is very unusual to have the clinical crowns of both primary and permanent teeth in such close proximity within the alveolar bone, and the present case is a good example to emphasize that trauma to the primary teeth is of considerable importance due to the close proximity of the primary teeth to permanent tooth germs. PMID:23305157

Anthonappa, Robert P; Ongtengco, Kristine L; King, Nigel M

2013-10-01

115

Human mandibular incisors from the late Middle Pleistocene locality of Hoedjiespunt 1, South Africa.  

PubMed

The Hoedjiespunt 1 locality is an archaeological and palaeontological site located on the Hoedjiespunt Peninsula at Saldanha Bay, South Africa. In 1996 two human teeth, a left central mandibular incisor and a left lateral mandibular incisor, were discovered during excavations in the late Middle Pleistocene palaeontological layers. These teeth are described and are found to belong to a single subadult individual. Despite their developmental stage, these incisors already display early signs of wear. Their crown diameters are larger than modern and archaeological African comparative material and are most closely comparable with crown diameters of an early Middle Pleistocene and late Middle Pleistocene dental sample from Africa, Europe and Asia. In the light of this metrical evidence, data on two previously excavated maxillary molars, most probably belonging to the same individual, were re-examined. It was found that the Hoedjiespunt 1 hominid possessed dental metrical features (large anterior teeth and small molars) comparable with other African and European hominids referred to the Middle Pleistocene. PMID:11681859

Stynder, D D; Moggi-Cecchi, J; Berger, L R; Parkington, J E

2001-11-01

116

Evaluation of the relationship between upper incisor exposure and cephalometric variables in Korean young adults  

PubMed Central

Objective The purpose of this study was to classify Korean young adults into 3 groups on the basis of upper incisor exposure rates (UIERs) and to compare the skeletal, dental, and soft tissue variables. Methods Samples were obtained from 127 students at the College of Dentistry, Wonkwang University in South Korea. Facial photographs of frontal posed smiles and lateral cephalograms of the subjects were taken. The subjects were divided into 3 groups on the basis of UIERs and 20 measurements were compared among the 3 groups. The correlations between the variables were determined. Results Male and female subjects showed significant differences in the group distribution. Male subjects showed higher frequencies of low smiles, and female subjects showed higher frequencies of high smiles. The vertical height of the anterior alveolar process of the maxilla directly correlated with the UIER. However, the UIER showed no significant correlation with the vertical height of the anterior basal bone or the inclination of the upper incisor axis. In female subjects, the upper central incisor clinical crown length showed an inverse correlation with the UIER. However, this variable showed no significant correlation with the UIER in male subjects. Conclusions The UIER was directly correlated with the levator muscle activity of the upper lip and inversely correlated with the upper lip thickness, yet there was no correlation between the UIER and upper lip length at rest.

Han, Sung-Hoon; Lee, Eon-Hwa; Cho, Jin-Hyoung; Chae, Jong-Moon; Kim, Sang-Cheol; Chang, Na-Young

2013-01-01

117

Hyaluronic acid-based scaffold for central neural tissue engineering  

PubMed Central

Central nervous system (CNS) regeneration with central neuronal connections and restoration of synaptic connections has been a long-standing worldwide problem and, to date, no effective clinical therapies are widely accepted for CNS injuries. The limited regenerative capacity of the CNS results from the growth-inhibitory environment that impedes the regrowth of axons. Central neural tissue engineering has attracted extensive attention from multi-disciplinary scientists in recent years, and many studies have been carried out to develop cell- and regeneration-activating biomaterial scaffolds that create an artificial micro-environment suitable for axonal regeneration. Among all the biomaterials, hyaluronic acid (HA) is a promising candidate for central neural tissue engineering because of its unique physico-chemical and biological properties. This review attempts to outline current biomaterials-based strategies for CNS regeneration from a tissue engineering point of view and discusses the main progresses in research of HA-based scaffolds for central neural tissue engineering in detail.

Wang, Xiumei; He, Jin; Wang, Ying; Cui, Fu-Zhai

2012-01-01

118

View west; interior view of central bay Naval Base ...  

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

View west; interior view of central bay - Naval Base Philadelphia-Philadelphia Naval Shipyard, Foundry-Propeller Shop, North of Porter Avenue, west of Third Street West, Philadelphia, Philadelphia County, PA

119

View east; interior view of central bay Naval Base ...  

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

View east; interior view of central bay - Naval Base Philadelphia-Philadelphia Naval Shipyard, Foundry-Propeller Shop, North of Porter Avenue, west of Third Street West, Philadelphia, Philadelphia County, PA

120

Onset of molar incisor hypomineralization (MIH).  

PubMed

The etiological factors and timing of the onset of molar incisor hypomineralization (MIH) are still not clear. The aim of this study was to examine ground radial and sagittal sections from teeth diagnosed with MIH using light microscopy, polarized light microscopy and X-ray micro-computed tomography (XMCT) and to estimate the onset and timing of the MIH and to relate the hypomineralized enamel to the incremental lines. Thirteen extracted permanent first molars diagnosed MIH, were analyzed with light microscopy and XMCT. The hypomineralized areas were mainly located in the mesio-buccal cusps, starting at the enamel-dentin-junction and continuing towards the enamel surface. In a relative gray scale analysis the values decreased from the EDJ towards the enamel surface. The findings indicate that the ameloblasts in the hypomineralized enamel are capable of forming an enamel of normal thickness, but with a substantial reduction of their capacity for maturation of enamel. Chronologically, it is estimated that the timing of the disturbance is at a period during the first 6-7 months of age. PMID:23957140

Fagrell, Tobias G; Salmon, Phil; Melin, Lisa; Norén, Jörgen G

2013-01-01

121

Electron microprobe analyses of Ca, S, Mg and P distribution in incisors of Spacelab-3 rats  

NASA Technical Reports Server (NTRS)

The distribution of Ca, S, Mg and P was mapped within the incisors of Spacelab-3 rats using an electron microprobe. The data indicate that Flight rats maintained in orbit for 7 days have significantly higher Ca/Mg ratios in dentin due to both higher Ca and lower Mg content than in dentin of ground-based Controls. There is no statistical difference in distribution of either P or S within Fligth animals and Controls, but there is clear indication that, for P at least, the reason is the greater variability of the Control data. These results are consistent with those obtained on a previous NASA/COSMOS flight of 18.5 days duration, although they are not pronounced. The results further suggest that continuously growing rat incisors provide useful records of the effects of weightlessness on Ca metabolism.

Rosenberg, G. D.; Simmons, D. J.

1985-01-01

122

Transposition of Mandibular Lateral Incisor-Canine (Mn.I2.C) Associated with Hypodontia: A Review and Rare Clinical Case  

PubMed Central

Transposition is a unique and extreme form of ectopic eruption in which a permanent tooth develops and erupts in the position which is normally occupied by other permanent teeth. Tooth transpositions are rare and they can be complete or incomplete. The aetiology of transposition is still obscure. Various populations have been studied, to determine the prevalence of tooth transpositions. 20% of the transpositions which occur on the maxillary arch involve the canine and the lateral incisor. Although they are rare, transpositions may involve the maxillary lateral and central incisors. Among all transpositions, Mandibular Lateral Incisor-Canine (Mn.I2.C) is the rarest, with a prevalence rate of 0.03%. Although various reports have been published on tooth transpositions, very few have noted the agenesis of teeth, particularly Mn.I2.C and its management. We are reporting a rare clinical case with associated hypodontia.

Athimuthu, Anantharaj; Prasanna, Praveen; Jagadeesh, Ramya B

2014-01-01

123

[Begg mechanics in treatment of congenitally missing lateral incisor].  

PubMed

The maxillary lateral incisors are the most frequently missing teeth after the third molars. The cases with congenitally missing lateral incisors are treated either by orthodontically closing the spaces or by space regaining for prosthetic restorations. Malocclusion is the most effective factor for selecting the treatment method. Besides the characteristics of the malocclusion and interdigitation, the colour, the shape, the size and the position of the canines effect the treatment planning. In particular, Class II Div. 1 and Cl. I anterior crowding cases are the most convenient cases for orthodontically closing the missing lateral spaces. In these cases besides the treatment of the present malocclusion the reshaping of the canines is aimed and these teeth are moved to lateral spaces. In this article the treatment of a Cl. II Div. 1 malocclusion case with congenitally maxillary missing lateral incisor with Begg technique will be presented. The changes and variations of the Begg mechanics applied for this case will be discussed. PMID:2101648

Ci?er, S; Telli, A E

1990-04-01

124

Orthodontic Treatment of a Mandibular Incisor Extraction Case with Invisalign  

PubMed Central

Mandibular incisor extraction for orthodontic treatment is considered an unusual treatment option because of the limited number of patients that meet the criteria for such treatment. Accurate diagnosis and treatment planning is essential to achieve the desired results. Adult orthodontic patients are increasingly motivated by esthetic considerations and reject the idea of conventional fixed appliances. In recent years, Invisalign appliances have gained tremendous attention for orthodontic treatment of adult patients to meet their esthetic demands. In this case report, a case of Class I malocclusion was treated with mandibular incisor extraction using the Invisalign appliance system. Successful tooth alignment of both arches was achieved. The use of Invisalign appliance is an effective treatment option in adult patients with Class I malocclusion that requires incisor extraction due to moderate to severe mandibular anterior crowding.

Zawawi, Khalid H.

2014-01-01

125

A centralized protection scheme based on combined positional protection techniques  

Microsoft Academic Search

This paper presents a new protection scheme for high-speed protection of transmission lines, the Integrated Positional Protection scheme. The concept of integrated protection is firstly introduced, in which a centralized protection relay provides the protection for multiple transmission lines. The proposed scheme is based on a specially integrated relay unit, which is installed at each substation of a network and

Z. Q. Bo; M. Han; A. Klimek; B. H. Zhang; J. H. He; X. Z. Dong

2009-01-01

126

Management of palato radicular groove in a maxillary lateral incisor  

PubMed Central

This study is to report the rare localization of a radicular groove on the palatal aspect of the maxillary lateral incisor and to discuss the pathology and management of the concomitant endo-periodontal defect. Unilateral palato-radicular groove was located on the Maxillary right lateral incisor of an 18-year-old female patient. The groove was associated with deep local periodontal pocket resulting in pulp necrosis and the formation of a large periapical lesion. A collaborative management was carried out using a combination of endodontic therapy, surgical enucleation, odontoplasty, and periodontal regenerative procedure resulting the successful healing of the periapical lesion.

Kishan, K. V.; Hegde, Vani; Ponnappa, K. C.; Girish, T. N.; Ponappa, M. C.

2014-01-01

127

Demineralisation and incisor wear: An in vitro study  

Microsoft Academic Search

The rate of incisor tooth wear in sheep may be increased by the presence of acidic dietary components. The present study investigated the effect of a weak organic acid on exposed dentine in vitro. Dentine on the incisai edge of extracted, worn teeth was exposed for 1 week in buffered sodium lactate solutions, containing calcium (Ca) and phosphate (PO4 )

G. P. Bloxham; D. G. Purton

1991-01-01

128

Innervation of the mandibular incisors by the mental nerve  

Microsoft Academic Search

Purpose: This study tested the hypothesis that some sensory innervation to the lower incisor teeth comes from reentry of the terminal branches of the mental nerve through the labial plate of the anterior mandible.Patients and Methods: Ten cadaveric heads (20 sides) were dissected and studied to determine whether the mental nerve crossed the midline or reentered the labial plate. Using

M. A Pogrel; R Smith; R Ahani

1997-01-01

129

Factors associated with molar incisor hypomineralization in Thai children.  

PubMed

Molar incisor hypomineralization (MIH) is a qualitative developmental enamel defect that affects one to four permanent first molars, with or without involvement of permanent incisors. Its etiology is of systemic origin, but is not well understood. Therefore, we conducted this cross-sectional study to examine pre-, peri-, and postnatal risk factors for MIH among children, 7-8 yr of age, in urban areas of Khon Kaen, Thailand. Molar incisor hypomineralization defects were diagnosed using the European Academy of Pediatric Dentistry criteria. Mothers or primary caregivers were interviewed on maternal medical history and habits during pregnancy, pregnancy and delivery complications, and the child's medical history. Molar incisor hypomineralization defects were observed in 78 (27.7%) of 282 children. Multiple logistic regression analysis showed a statistically significant association between the development of MIH and Cesarean section (adjusted OR = 2.0, 95% CI = 1.1-3.7), complications during vaginal delivery (adjusted OR = 4.5, 95% CI = 1.9-11.0), and severe/chronic illness when under 3 yr of age (adjusted OR = 2.9, 95% CI = 1.6-5.0). There was no association of preterm birth and low birth weight with MIH. The results suggest that Cesarean section, complications during vaginal delivery, and poor health during the first 3 yr of life are independent risk factors for MIH. PMID:24924351

Pitiphat, Waranuch; Luangchaichaweng, Sarunporn; Pungchanchaikul, Patimaporn; Angwaravong, Onauma; Chansamak, Nusara

2014-08-01

130

Continuous and Short Fiber Reinforced Composite in Root Post-Core System of Severely Damaged Incisors  

PubMed Central

Purpose: The aim of this study was to determine the static load-bearing capacity of endodontically treated maxillary incisors restored with post-core complex made of experimental fiber composite resin (FC) and complete crown made of particulate filler composite (PFC). Further aim was to evaluate the effect of FC resin on the failure mode of the restoration. Material and Methods: The experimental composite resin (FC) was prepared by mixing 22.5 wt% of short E-glass fibers (3 mm in length) and 22.5 wt% of semi-interpenetrating polymer network (IPN) resin with 55 wt% of silane treated silica fillers. Thirty extracted sound upper central incisors were used. Twenty teeth were prepared by cutting the clinical crown 2 mm above the cemento-enamel junction horizontally. Restorations were made by two techniques (n=10). Group A (control group) contained samples of sound incisor teeth. Group B had teeth restored using glass fiber post (everStick, Stick- Teck) and PFC (Filtek Z250, 3M-ESPE) to build up core and complete crown. In Group C, the teeth were restored with FC as post-core and complete crown of PFC. The root canals were prepared and posts were cemented with a dual cure resin cement. The restorations were polymerized with a hand-light curing unit. All restored teeth were stored in water at room temperature for 24 h before they were statically loaded with speed of 1.0 mm/min until fracture. Data were analyzed using ANOVA (p=0.05). Failure modes were visually examined. Results: ANOVA revealed that restored incisors (Group B and C) had a statistically significantly lower load-bearing capacity (p<0.05) than the control group. Restorations made from FC post-core and PFC coverage (Group C) gave force value of 363 N (112 SD), which was higher than the value of Group B (211 N, 50 SD). Conclusions: Within the limitations of this study, the teeth restored with experimental fiber composite post-core demonstrated higher load bearing capacity than those with fiber post and PFC core.

Garoushi, Sufyan; Vallittu, Pekka K; Lassila, Lippo V.J

2009-01-01

131

The Response of the Rabbit Mandibular Incisor to Experimental Shortening and to the Prevention of Its Eruption  

Microsoft Academic Search

Measurements have been made of the eruption rates of the mandibular incisors of domestic rabbits, to examine the effects of shortening one or both incisors for a period of three weeks. Concomitant measurements were made of the rate of wear and the length of the incisors, and of a number of other values defining the occlusion of the lower incisors

A. R. Ness

1956-01-01

132

Bizarre cause for avulsion of permanent maxillary lateral incisor tooth.  

PubMed

A 9-year-old boy presented with a missing upper front tooth after an accident involving kite flying. Diagnosis of avulsion of the upper right lateral incisor (22) was made after examination of his socket as well as by radiological investigations. A removable partial denture was given for the aesthetic purpose. The patient is under follow-up. The present case illustrates the management of avulsion. PMID:23978496

Kiran, Shital; Bargale, Seema Dinesh; Sikligar, Smit; Shanthraj, Srinivas L

2013-01-01

133

Cadherin-related Neuronal Receptors in Incisor Development  

Microsoft Academic Search

Cadherins are cell adhesion molecules that are critical for tissue development. In this report, we identified members of the cadherin family cadherin-related neuronal receptors (CNRs) 1 and 5 expressed in rat incisors by the differential display method. Quantitative RT-PCR revealed that CNR1 mRNA is expressed in the secretory stage but reduced in the early-maturation stage, while CNR5 mRNA is expressed

E. Fukumoto; H. Sakai; S. Fukumoto; T. Yagi; O. Takagi; Y. Kato

2003-01-01

134

Oxygen distribution and consumption in rat lower incisor pulp  

Microsoft Academic Search

The aim was to determine the oxygen tension (PO2) and rate of oxygen consumption in the pulp. Twelve rats were anaesthetised and artificially ventilated. Under an operating microscope, a recessed oxygen-sensitive microelectrode was inserted into the pulp through a small saline-covered cavity on the labial surface of the lower incisor. PO2 was measured as a function of the transverse distance

C. Y Yu; N. M Boyd; S. J Cringle; V. A Alder; D. Y Yu

2002-01-01

135

[Dento-alveolar cleft and the lateral incisor].  

PubMed

In the period of 1980 to 1990, 55 cleft, lip and palate patients, ranging in age from nine to twelve years, were treated. With 52% of them the lateral incisor on the cleft side was agenetic, in 24% normally developed and in 24% malformed. The malformed and the fissural teeth were removed during bone grafting of the dento-alveolar cleft. In almost all cases a well-formed tooth arch could be obtained by orthodontic treatment. PMID:11917879

van der Wal, K G

1993-10-01

136

Agenesis of maxillary lateral incisor and tooth replacement: cost-effectiveness of different treatment alternatives.  

PubMed

Purpose: To evaluate the long-term cost-effectiveness of five treatment alternatives for maxillary lateral incisor agenesis where space maintenance and tooth replacement are indicated. Materials and Methods: The following treatment modalities were considered: single-tooth implant-supported crown, resin-bonded fixed partial denture (FPD), cantilever FPD, full-coverage FPD, and autotransplantation. The cost-effectiveness for each treatment modality was determined as the ratio of the outcome of each modality divided by the cost. Direct costs, clinical and laboratory, were calculated based on national fee schedules and converted to international dollars using purchasing power parity exchange rates. Outcomes were based on the most recently published long-term (10-year) survival rates. Sensitivity analyses were carried out, testing the robustness of the cost-effectiveness analysis. Results: The five treatment modalities ranked in the following order from most to least cost-effective: autotransplantation, cantilever FPDs, resin-bonded FPDs, single-tooth implants and implant-supported crowns, and full-coverage FPDs. Sensitivity analysis illustrated that the cost-effectiveness analysis was reliable in identifying autotransplantation as the most and full-coverage FPDs as the least cost-effective treatment modalities. Conclusions: When replacing a missing maxillary lateral incisor, the most costeffective, long-term treatment modality is autotransplantation, whereas the least cost-effective is full-coverage FPDs. However, factors such as patient age, the state of the dentition, occlusion, and tooth conservation should also influence the choice of restoration. PMID:24905267

Antonarakis, Gregory S; Prevezanos, Panagiotis; Gavric, Jelena; Christou, Panagiotis

2014-01-01

137

Longitudinal clinical and radiographic evaluation of severely intruded permanent incisors in a pediatric population.  

PubMed

Intrusion is defined as the axial dislodgment of the tooth into its socket and is considered one of the most severe types of dental trauma. This longitudinal outcome study was undertaken to evaluate clinically and radiographically severely intruded permanent incisors in a population of children and adolescents. All cases were treated between September 2003 and February 2008 in a dental trauma service. Clinical and radiographic data were collected from 12 patients (eight males and four females) that represented 15 permanent maxillary incisors. Mean age at the time of injury was 8 years and 9 months (range 7-14 years and 8 months). Mean time elapsed to follow-up was 26.6 months (range 10-51 months). The analysis of data showed that tooth intrusion was twice as frequent in males. The maxillary central incisors were the most commonly intruded teeth (93.3%), and falling at home was the main etiologic factor (60%). More than half of the cases (53.3%) were multiple intrusions, 73.3% of the intruded teeth had incomplete root formation and 66.6% of the teeth suffered other injuries concomitant to intrusion. Immediate surgical repositioning was the treatment of choice in 66.7% of the cases, while watchful waiting for the tooth to return to its pre-injury position was adopted in 33.3% of the cases. The teeth that suffered additional injuries to the intrusive luxation presented a fivefold increased relative risk of developing pulp necrosis. The immature teeth had six times more chances of presenting pulp canal obliteration that the mature teeth and a lower risk of developing root resorption. The most frequent post-injury complications were pulp necrosis (73.3%), marginal bone loss (60%), inflammatory root resorption (40%), pulp canal obliteration (26.7%) and replacement root resorption (20%). From the results of this study, it was not possible to determine whether the type immediate treatment had any influence on the appearance of sequelae like pulp necrosis and root resorption after intrusive luxation, but the existence of additional injuries and the stage of root development influenced the clinical case outcome in a negative and positive manner, respectively. PMID:19614934

Neto, José Jeová Siebra Moreira; Gondim, Juliana Oliveira; de Carvalho, Fernanda Matias; Giro, Elisa Maria Aparecida

2009-10-01

138

Three-dimensional analysis of the change in the curvature of the smiling line following orthodontic treatment in incisor class II division 1 malocclusion.  

PubMed

OBJECTIVES:To investigate the different effects of changes in the occlusal plane, incisors inclination, and maxillary intercanine width on the curvature of the smiling line.MATERIALS:Records of 46 subjects (28 females and 18 males, mean age 16.6±4.2 years) with incisor class II division 1 malocclusions were selected. All subjects had four premolar extractions and were treated with preadjusted edgewise appliances.METHODS:Pre- and post-treatment maxillary dental digital models were virtually aligned via corresponding landmarks to the respective lateral cephalograms. Subsequent two-dimensional superimposition of the aligned cephalograms facilitated the three-dimensional superimposition of the pre- and post-treatment models. This process allowed the quantification of the curvature from a frontal perspective of the models. The change in curvature was then correlated with changes in the cephalometric inclination of the anterior occlusal plane (AOP), functional occlusal plane (FOP), maxillary central incisor (U1), and the intercanine width.RESULTS:Orthodontic correction in this sample resulted in the clockwise rotation of the anterior occlusal plane (5.84 degrees), reduction in proclination of the incisors (-14.39 degrees), increase in intercanine width (2.48mm), and a corresponding increase in the curvature of the smiling line (6.83 degrees).CONCLUSIONS:The change in curvature of the smiling line in these subjects was found to be related more significantly to the magnitude of difference in the inclination between the pre-treatment AOP and FOP than to the change in the inclination of the maxillary incisors. With orthodontic treatment, the smiling line can be correlated with cephalometric data to improve or maintain the curvature. PMID:23771899

Mah, Michael; Chuan Tan, Wei; Heng Ong, Sim; Huak Chan, Yiong; Foong, Kelvin

2013-06-14

139

Response of human jaw muscles to axial stimulation of the incisor  

PubMed Central

The role of periodontal mechanoreceptors (PMRs) in the reflex control of the jaw muscles has thus far been mainly derived from animal studies. To date, the work that has been done on humans has been limited and confined to orthogonal stimulation of the labial surface of the tooth. The purpose of this study was to investigate the response of the masseter and digastric muscles in humans to controlled axial stimulation of the upper left central incisor, both before and during a local anaesthetic block of the PMRs. Ten neurologically normal young adult females were tested, each on two separate occasions to confirm the reproducibility of the results. It was found that the reflex response in the masseter was modulated by the rate of rise of the stimulus used and, to a lesser degree, the level of background muscle activity. There was little detectable change in the activity of the digastric muscle under the tested conditions and what was found could be attributed to cross-talk with the masseter. The reflex responses obtained were significantly different between subjects; however retesting the same subject on a different occasion yielded similar results. The results indicate that the most common response of the masseter muscle to brisk axial stimulation of the incisor is a reflex inhibition at 20 ms, followed by a late excitation at 44 ms. However, it is possible that this late excitation could be due to delayed action potentials and hence be artefactual. As the application of a local anaesthetic block removed or significantly reduced both of these responses, it was concluded that they originated from the PMRs. Unlike during orthogonal stimulation, slowly rising stimuli did not produce any excitatory reflex activity. This indicated a difference in jaw reflexes to forces applied in different directions, possibly due to the activation of different receptor types when stimulating the tooth in either the orthogonal or axial directions.

Brinkworth, Russell S A; Turker, Kemal S; Savundra, Andrew W

2003-01-01

140

Non-linear viscoelastic finite element analysis of the effect of the length of glass fiber posts on the biomechanical behaviour of directly restored incisors and surrounding alveolar bone.  

PubMed

The study aimed at estimating the effect of insertion length of posts with composite restorations on stress and strain distributions in central incisors and surrounding bone. The typical, average geometries were generated in a FEA environment. Dentin was considered as an elastic orthotropic material, and periodontal ligament was coupled with nonlinear viscoelastic mechanical properties. The model was then validated with experimental data on displacement of incisors from published literature. Three post lengths were investigated in this study: root insertion of 5, 7, and 9 mm. For control, a sound incisor model was generated. Then, a tearing load of 50 N was applied to both sound tooth and simulation models. Post restorations did not seem to affect the strain distribution in bone when compared to the control. All simulated post restorations affected incisor biomechanics and reduced the root's deforming capability, while the composite crowns underwent a higher degree of deformation than the sound crown. No differences could be noticed in incisor stress and strain. As for the influence of post length, it was not shown to affect the biomechanics of restored teeth. PMID:18833761

Ferrari, Marco; Sorrentino, Roberto; Zarone, Fernando; Apicella, Davide; Aversa, Raffaella; Apicella, Antonio

2008-07-01

141

A centralized quantum switch network based on probabilistic channels  

NASA Astrophysics Data System (ADS)

We present a practical scheme for deterministically teleporting quantum information via probabilistic communication channels in a centralized quantum switch network. In the network, a central quantum switch agent is assigned for regulating probabilistic channels so as to construct a direct deterministic channel between the sender and the receiver. This scheme is further extended to a hierarchical network and a tree network involving multiple agents. The advantage of the scheme is that all required multi qubit gates from distributed terminal agents are uniformly performed by a central agent, with which the physical design of terminal nodes is greatly simplified and more reliable deterministic teleportation can be realized in a centralized quantum probabilistic network.

Jiang, Min; Wu, Re-Bing; Li, Hui; Zhang, Zeng-ke

2013-01-01

142

Orthodontic Management of Congenitally Missing Maxillary Lateral Incisors: A Case Report  

PubMed Central

This case report describes the orthodontic treatment of a woman, aged 15 years, with permanent dentition, brachyfacial typology, with congenitally missing maxillary lateral incisors. Multibracket straightwire fixed appliance was used to open the space for dental implant placement, and treat the impaired occlusion. The missing lateral incisors were substituted with oral implants.

Rongo, Roberto; Cupo, Antonello; Valletta, Rosa

2014-01-01

143

Control of mandibular incisors with the combined Herbst and completely customized lingual appliance - a pilot study  

Microsoft Academic Search

BACKGROUND: The traditional Herbst appliance induces mandibular incisor proclination independent of the anchorage system used. The dental effects of the Herbst appliance as an element of a completely customized lingual orthodontic (LO) appliance (Incognito, 3 M) has not been analyzed yet and the aim of this paper was to measure the effect of mandibular incisor proclination using this Herbst-LO device.

Dirk Wiechmann; Rainer Schwestka-Polly; Hans Pancherz; Ariane Hohoff

2010-01-01

144

Identification of genetic risk factors for maxillary lateral incisor agenesis.  

PubMed

Tooth agenesis affects 20% of the world population, and maxillary lateral incisors agenesis (MLIA) is one of the most frequent subtypes, characterized by the absence of formation of deciduous or permanent lateral incisors. Odontogenesis is a complex mechanism regulated by sequential and reciprocal epithelial-mesenchymal interactions, controlled by activators and inhibitors involved in several pathways. Disturbances in these signaling cascades can lead to abnormalities in odontogenesis, resulting in alterations in the formation of the normal teeth number. Our aim was to study a large number of genes encoding either transcription factors or key components in signaling pathways shown to be involved in tooth odontogenesis. We selected 8 genes-MSX1, PAX9, AXIN2, EDA, SPRY2, TGFA, SPRY4, and WNT10A-and performed one of the largest case-control studies taking into account the number of genes and variants assessed, aiming at the identification of MLIA susceptibility factors. We show the involvement of PAX9, EDA, SPRY2, SPRY4, and WNT10A as risk factors for MLIA. Additionally, we uncovered 3 strong synergistic interactions between MLIA liability and MSX1-TGFA, AXIN2-TGFA, and SPRY2-SPRY4 gene pairs. We report the first evidence of the involvement of sprouty genes in MLIA susceptibility. This large study results in a better understanding of the genetic components and mechanisms underlying this trait. PMID:24554542

Alves-Ferreira, M; Pinho, T; Sousa, A; Sequeiros, J; Lemos, C; Alonso, I

2014-05-01

145

Central neurocytoma: Management recommendations based on a 35-year experience  

Microsoft Academic Search

Purpose: To examine the outcomes of patients with histologically confirmed central neurocytomas. Methods and Materials: The data from 45 patients with central neurocytomas diagnosed between 1971 and 2003 were retrospectively evaluated. Various combinations of surgery, radiotherapy (RT), and chemotherapy had been used for treatment. Results: The median follow-up was 10.0 years. The 10-year overall survival and local control rate was

James L. Leenstra; Fausto J. Rodriguez; Christina M. Frechette; Caterina Giannini; Scott L. Stafford; Bruce E. Pollock; Steven E. Schild; Bernd W. Scheithauer; Robert B. Jenkins; Jan C. Buckner; Paul D. Brown

2007-01-01

146

A study of the ultrastructure and staining characteristics of the 'dental star' of equine incisors.  

PubMed

The objective of this study was to examine the diameter, extent, orientation and contents of dentinal tubules in order to validate the hypothesis of pigment penetration into the dental star of equine incisival occlusal surfaces. The time of appearance and the configuration of the dental star on the incisival occlusal surface are macroscopically visible features that, along with other more reliable parameters, are used for the determination of horses' age. Although dental stars are an integral part of the equine incisor occlusive surface, the exact nature and microstructure of the dental star are poorly documented. Therefore, equine incisor dentine was examined macroscopically and by scanning electron microscopy to elucidate numerical density, diameter and 3-dimensional organisation of the dentinal tubules in the dental star. The dental star is surrounded by primary dentine and consists of a central core of tertiary dentine, an intermediate ring of pale secondary dentine and a peripheral rim of darker, yellowish-brown secondary dentine. The central core of tertiary dentine contains relatively few dentinal tubules (<8000/mm2) that have small diameters (mean +/- s.d. 1.67 +/- 034 microm) and are arranged in an irregular pattern. The surrounding pale ring of secondary dentine comprises manifestly more and wider tubules that lie almost parallel to the occlusal surface. The dark peripheral rim of the dental star contains high numbers of tubules (28,000-58,000/mm2) that have wide luminal diameters (mean +/- s.d. 3.09 +/- 0.31 microm) and open perpendicular to the occlusal surface. In contrast, the primary dentine surrounding the dental star is made up by a lower number of dentinal tubules (<25,000/mm2). The tubules of primary dentine, which are initially mean +/- s.d. 5.15 +/- 0.80 microm wide, are narrowed by circumferential deposits of peritubular dentine and are obliquely exposed at the occlusal surface. From these observations, it was concluded that the regional differences in numerical density, diameter and spatial orientation of the dentinal tubules may influence the penetration of food pigments into the equine occlusal surface and result in the particular staining of the dental star. PMID:12108739

Muylle, S; Simoens, P; Lauwers, H

2002-05-01

147

Correction of palatally displaced maxillary lateral incisors without brackets  

PubMed Central

This article describes the orthodontic treatment of a 25-year-old Korean female patient with anterior crowding, including palatally displaced lateral incisors. Her facial profile was satisfactory, but 3.5 mm of maxillary anterior crowding was observed. To correct this crowding, we decided to minimize the use of the conventional fixed orthodontic appliances and employed a less bulky and more aesthetic appliance for applying light continuous force. We determined the final positions of the maxillary teeth via a working model for diagnostic set up and achieved space gaining and alignment with simple Ni-Ti spring and stainless steel round tubes. Tooth alignment was achieved efficiently and aesthetically without the conventional brackets.

Choi, Kyung-Hee; Lee, Yoonjung; Kim, Minji

2013-01-01

148

Angle Class I malocclusion treated with lower incisor extraction.  

PubMed

In planning orthodontic cases that include extractions as an alternative to solve the problem of negative space discrepancy, the critical decision is to determine which teeth will be extracted. Several aspects must be considered, such as periodontal health, orthodontic mechanics, functional and esthetic alterations, and treatment stability. Despite controversies, extraction of teeth to solve dental crowding is a therapy that has been used for decades. Premolar extractions are the most common, but there are situations in which atypical extractions facilitate mechanics, preserve periodontal health and favor maintenance of the facial profile, which tends to unfavorably change due to facial changes with age. The extraction of a lower incisor, in selected cases, is an effective approach, and literature describes greater post-treatment stability when compared with premolar extractions. This article reports the clinical case of a patient with Angle Class I malocclusion and upper and lower anterior crowding, a balanced face and harmonious facial profile. The presence of gingival and bone recession limited large orthodontic movements. The molars and premolars were well occluded, and the discrepancy was mainly concentrated in the anterior region of the lower dental arch. The extraction of a lower incisor in the most ectopic position and with compromised periodontium, associated with interproximal stripping in the upper and lower arches, was the alternative of choice for this treatment, which restored function, providing improved periodontal health, maintained facial esthetics and allowed finishing with a stable and balanced occlusion. This case was presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO), as part of the requirements for obtaining the BBO Diplomate title. PMID:24094026

Barbosa, Vanessa Leal Tavares

2013-01-01

149

Nanobiotechnology-Based Drug Delivery to the Central Nervous System  

Microsoft Academic Search

Background: Drug delivery across the blood-brain barrier (BBB) is a major limitation in the treatment of central nervous system (CNS) disorders. Several approaches are being investigated to improve drug delivery across the BBB. Objective\\/Methods: This review deals with the role of nanobiotechnology in CNS drug delivery. The small size of the nanoparticles enables them to penetrate the BBB and facilitate

K. K. Jain

2007-01-01

150

Weighting links based on edge centrality for community detection  

NASA Astrophysics Data System (ADS)

Link weights have the equally important position as links in complex networks, and they are closely associated with each other for the emergence of communities. How to assign link weights to make a clear distinction between internal links of communities and external links connecting communities is of vital importance for community detection. Edge centralities provide a powerful approach for distinguishing internal links from external ones. Here, we first use edge centralities such as betweenness, information centrality and edge clustering coefficient to weight links of networks respectively to transform unweighted networks into weighted ones, and then a weighted function that both considers links and link weights is adopted on the weighted networks for community detection. We evaluate the performance of our approach on random networks as well as real-world networks. Better results are achieved on weighted networks with stronger weights of internal links of communities, and the results on unweighted networks outperform that of weighted networks with weaker weights of internal links of communities. The availability of our findings is also well-supported by the study of Granovetter that the weak links maintain the global integrity of the network while the strong links maintain the communities. Especially in the Karate club network, all the nodes are correctly classified when we weight links by edge betweenness. The results also give us a more comprehensive understanding on the correlation between links and link weights for community detection.

Sun, Peng Gang

2014-01-01

151

Embrasure morphology and central papilla recession  

PubMed Central

Background: The aim of this study was to ascertain the effects of vertical and horizontal distances between the maxillary central incisors on the presence of interproximal dental papilla and to assess the association between the embrasure morphology and central papilla recession. Materials and Methods: The central papilla was visually assessed in 50 subjects using the standardized periapical radiographs of maxillary central incisors. The following vertical distances were measured; distance from the contact point to papilla tip, CP to proximal cementoenamel (pCEJ) junction, bone crest to CP (BC-CP) and BC-PT. The horizontal distance measured was interdental width (IDW) at pCEJ level. The measurements were recorded using a digital electronic caliper. Results: Significant association between the embrasure morphology and central papilla recession was observed for all study groups. All the interdental variables were significantly related to the presence of interdental papillae, with BC-CP distance being the strongest determinant of central papilla presence. The percentage of interdental papilla presence was 100% when the BC-CP distance was ?6 mm and IDW ranged between 0.5 and 1.5 mm. Central papilla recession was observed most frequently with wide-long and narrow-long embrasure morphology. Conclusion: In relation to maxillary central incisors, all the interdental variables have significant influences on the presence of interdental papillae, with distance from BC to CP being the strongest determinant of central papilla presence.

Saxena, Divya; Kapoor, Anoop; Malhotra, Ranjan; Grover, Vishakha

2014-01-01

152

Immediate Osseotite implant placement and immediate loading of a provisional restoration of maxillary lateral incisors.  

PubMed

This article describes the immediate replacement of two maxillary lateral incisors teeth after extraction of the left lateral deciduous incisor at the same time with immediate Osseotite implants and immediate restoration. A traumatic dental extraction of a deciduos (b) lateral incisor was performed and a 4mm diameter x 15 mm 3i tapered Osseotite (Implants Innovations, Palm Beach, CA, USA) implant was immediately placed. The other lateral incisor place was treated at the same time and provisional temporary crowns were placed at the same surgery. The provisional crowns did not have any occlusal contact to reduce negative lateral forces. Final impression for definitive restoration was made five months after implant placement veneer ceramic crowns were bonded to the Gingihue abutment (3i, Implants Innovations, Palm Beach, CA) one month later. This article describes the use of immediate implants with immediate loading of Osseotite combined with provisional crowns resulted in an excellent outcome after a two-year follow up period. PMID:16358677

Guirado, Calvo; Luis, José; Yuguero, Saez; Rosario, Mo; Pardo Zamora, Guillermo; Muñoz Barrio, Emilio

2005-01-01

153

Immunohistochemical detection of heme oxygenase-2 in the periodontal Ruffini ending of the rat incisor  

Microsoft Academic Search

The present study was carried out to examine the occurrence of heme oxygenase-2 (HO-2) in the periodontal ligament of the rat incisor. HO-2-like immunoreactive (-IR) structures showed dendritic profiles, resembling the Ruffini endings, in the alveolar half of the ligament of rat incisor. Neither thin nerve fibers nor perivascular nerve fibers displayed HO-2-like immunoreactivity (-LI). No non-neural elements exhibited HO-2-LI.

Yukako Atsumi; Takumi Imai; Takeyasu Maeda; Kojiro Kurisu; Satoshi Wakisaka

2000-01-01

154

Temporal Analysis of Ectopic Enamel Production in Incisors From Sprouty Mutant Mice  

PubMed Central

The mouse incisor has two unusual features: it grows continuously and it is covered by enamel exclusively on the labial side. The continuous growth is driven in part by epithelial stem cells in the cervical loop region that can both self-renew and give rise to ameloblasts. We have previously reported that ectopic enamel is found on the lingual side of the incisor in mice with loss-of-function of sprouty (spry) genes. Spry2+/?; Spry4?/? mice, in which three sprouty alleles have been inactivated, have ectopic enamel as a result of upregulation of epithelial-mesenchymal FGF signaling in the lingual part of the cervical loop. Interestingly, lingual enamel is also present in the early postnatal period in Spry4?/? mice, in which only two sprouty alleles have been inactivated, but ectopic enamel is not found in adults of this genotype. To explore the mechanisms underlying the disappearance of lingual enamel in Spry4?/? adults, we studied the fate of the lingual enamel in Spry4?/? mice by comparing the morphology and growth of their lower incisors with wild type and Spry2+/?; Spry4?/? mice at several timepoints between the perinatal period and adulthood. Ameloblasts and enamel were detected on the lingual side in postnatal Spry2+/?; Spry4?/+ incisors. By contrast, new ectopic ameloblasts ceased to differentiate after postnatal day 3 in Spry4?/? incisors, which was followed by a progressive loss of lingual enamel. Both the posterior extent of lingual enamel and the time of its last deposition were variable early postnatally in Spry4?/? incisors, but in all Spry4?/? adult incisors the lingual enamel was ultimately lost through continuous growth and abrasion of the incisor.

Boran, Tomas; Peterkova, Renata; Lesot, Herve; Lyons, David B.; Peterka, Miroslav; Klein, Ophir D.

2010-01-01

155

Effect of single-dose amoxicillin on rat incisor odontogenesis: a morphological study  

Microsoft Academic Search

The effect of exposure to amoxicillin on tooth development remains to be elucidated. The purpose of this study was to investigate\\u000a the effect of amoxicillin on rat incisor odontogenesis. Male Wistar rats weighing approximately 100 g were given a single\\u000a intraperitoneal injection of 3.0 g\\/kg body weight amoxicillin. One week after injection, the rats were fixed, and the lower\\u000a incisors were demineralized

Kaido Kumazawa; Takashi Sawada; Takaaki Yanagisawa; Seikou Shintani

156

A Comparative Study of Disturbed Mineralization of Rat Incisor Enamel Induced By Strontium and Fluoride Administration  

Microsoft Academic Search

The disturbed pattern of mineralization of developing enamel of the rat incisor after the oral administration of SrCl2 and NaF was investigated in an attempt to disclose possible mechanisms which might not be readily detectable under normal conditions, but which may control the progressive mineralization of developing enamel, especially during the maturation stage. Undemineralized ground sections of upper incisors were

S. Suga; H. Aoki; Y. Yamashita; M. Tsuno; M. Ogawa

1987-01-01

157

Temporal analysis of ectopic enamel production in incisors from sprouty mutant mice.  

PubMed

The mouse incisor has two unusual features: it grows continuously and it is covered by enamel exclusively on the labial side. The continuous growth is driven in part by epithelial stem cells in the cervical loop region that can both self-renew and give rise to ameloblasts. We have previously reported that ectopic enamel is found on the lingual side of the incisor in mice with loss-of-function of sprouty (spry) genes. Spry2(+/-); Spry4(-/-) mice, in which three sprouty alleles have been inactivated, have ectopic enamel as a result of upregulation of epithelial-mesenchymal FGF signaling in the lingual part of the cervical loop. Interestingly, lingual enamel is also present in the early postnatal period in Spry4(-/-) mice, in which only two sprouty alleles have been inactivated, but ectopic enamel is not found in adults of this genotype. To explore the mechanisms underlying the disappearance of lingual enamel in Spry4(-/-) adults, we studied the fate of the lingual enamel in Spry4(-/-) mice by comparing the morphology and growth of their lower incisors with wild type and Spry2(+/-); Spry4(-/-) mice at several timepoints between the perinatal period and adulthood. Ameloblasts and enamel were detected on the lingual side in postnatal Spry2(+/-); Spry4(+/-) incisors. By contrast, new ectopic ameloblasts ceased to differentiate after postnatal day 3 in Spry4(-/-) incisors, which was followed by a progressive loss of lingual enamel. Both the posterior extent of lingual enamel and the time of its last deposition were variable early postnatally in Spry4(-/-) incisors, but in all Spry4(-/-) adult incisors the lingual enamel was ultimately lost through continuous growth and abrasion of the incisor. PMID:19101957

Boran, Tomas; Peterkova, Renata; Lesot, Herve; Lyons, David B; Peterka, Miroslav; Klein, Ophir D

2009-07-15

158

Does orthodontic proclination of lower incisors in children and adolescents cause gingival recession?  

Microsoft Academic Search

In this investigation we sought to assess the effect of orthodontic proclination of lower incisors in children and adolescents with respect to the possible development of gingival recession. Ninety-eight children with a mean ± SD start-of-treatment age of 12.8 ± 1.4 years, treated with the Herbst appliance, were surveyed, for a total of 392 lower incisors. Lateral head films, dental

Sabine Ruf; Ken Hansen; Hans Pancherz

1998-01-01

159

Aesthetic Rehabilitation of a Complicated Crown-Root Fracture of the Maxillary Incisor: Combination of Orthodontic and Implant Treatment  

PubMed Central

The aim of this paper is to present a complex rehabilitation, of fractured tooth, with implants in anterior region considering the orthodontics extrusion to clinical success. At 7 years old, the patient fractured the maxillary left central incisor and the dentist did a crown with the fragment. Twenty years later, the patient was referred to a dental clinic for orthodontic treatment, with the chief complaint related to an accentuated deep bite, and a professional started an orthodontic treatment. After sixteen months of orthodontic treatment, tooth 21 fractured. The treatment plan included an orthodontic extrusion of tooth 21 and implant placement. This case has been followed up and the clinical and radiographic examinations show excellence esthetic results and satisfaction of patient. The forced extrusion can be a viable treatment option in the management of crown root fracture of an anterior tooth to gain bone in a vertical direction. This case emphasizes that to achieve the esthetic result a multidisciplinary approach is necessary.

de Avila, Erica Dorigatti; de Molon, Rafael Scaf; Cardoso, Mauricio de Almeida; Capelozza Filho, Leopoldino; Campos Velo, Marilia Mattar de Amoedo; Mollo, Francisco de Assis; Borelli Barros, Luiz Antonio

2014-01-01

160

Malignant Lesions of the Central and Posterior Skull Base  

Microsoft Academic Search

Evaluation of skull base lesions is challenging. On the one hand, the skull base is not directly accessible for clinical evaluation,\\u000a and an underlying lesion is suspected or can be only roughly outlined based on neurological deficits. On the other, cross-sectional\\u000a radiological studies are excellent in demonstrating a skull base lesion and its extent, but their evaluation is intimidating\\u000a to

Ilona M. Schmalfuss

161

Association of dentoskeletal morphology with incisor inclination in angle class II patients: a retrospective cephalometric study  

PubMed Central

Introduction The purpose of this study was to identify possible dentoskeletal parameters associated with variation of anterior tooth inclination in Angle Class II subdivisions. Methods Pre-treatment lateral radiographs of 144 Class II patients (68 males, 76 females) aged 9 to 17 years were classified for upper incisor inclination into three groups (proclined, normally inclined, retroclined) homogeneous for gender and skeletal jaw relationship. The effect of age on the 22 cephalometric variables was controlled by covariance analysis. Results Multivariate analysis of the cephalometric parameters indicated significant inter-group differences. Systematic associations with incisor inclination were revealed using rank correlation: Lower incisor proclination, Wits appraisal and gonial angle significantly decreased (0.04 ? p ? 0.002), while intercisal angle, mandibular total and corpus length and nasolabial angle increased (0.04 ? p ? 0.001) with decreasing incisor proclination. Conclusions Clear-cut classification criteria and control of confounding effects may clarify conflicting previous findings on dentoskeletal differences between Class II subdivisions in the mixed dentition. Only minor dentoskeletal differences appear to be associated with incisor inclination. The increased interincisal and nasolabial angle in Class II division 2 subjects are due to reclination of both upper and lower incisors. Jaw positions and chin prominence are not significantly different between the subdivisions. However, Wits appraisal is decreased in Class II division 2. The increased mandibular length observed in Class II division 2 requires further scrutinization.

2013-01-01

162

Cross-sectional study of correlation between mandibular incisor crowding and third molars in young Brazilians  

PubMed Central

Objectives: The aim of this study was to evaluate transversally the clinical correlation between lower incisor crowding and mandible third molar. Study Design: Three hundred healthy volunteers (134 male and 166 female), aged 20.4 (±2.4) years-old were submitted to a complete clinical examination and filled up a questionnaire about gender, age, total teeth number and presence or absence of superior and inferior third molar. After a recent panoramic radiography were evaluated. The multiple logistic regression showed that none of the studied factors influenced the mandibular incisor crowding. Results: The proportion of both molars present or both absent was higher than the other conditions (Chi-square, p<.0001). The multiple logistic regression showed that any of the studied factors, influenced (p>.05) the mandibular incisor crowding. Despite the statistical significance, wear orthodontics appliances showed a little correlation (odds ratios < 1.0) in the mandibular incisor crowding. Conclusion: Presence of maxillary and/or mandibular third molars has no relation with the lower incisor crowding. Key words:Malocclusion, third molars, lower incisor crowding, mandible.

Karasawa, Lilian H.; Groppo, Francisco C.; Prado, Felippe B.; Caria, Paulo H F.

2013-01-01

163

Extraction of the lateral incisors to treat maxillary protrusion: quantitative evaluation of the stomatognathic functions.  

PubMed

To treat morphological abnormalities, impaction, and severe malposition of the teeth, the lateral incisors are sometimes extracted, followed by orthodontic space closure. This procedure often requires special consideration, not only with regard to esthetics but also for functional issues. However, thus far, few reports that have performed a functional evaluation in such cases. The purpose of this article is to report the successful treatment of an adult patient with a Class II division 1 malocclusion who was treated with extraction of the upper lateral incisors. The female patient, aged 23 years and 6 months, had a chief complaint of maxillary incisal protrusion and crooked teeth. In this patient, the upper lateral incisors were extracted to fulfill the patient's strong request, followed by orthodontic treatment using edgewise appliances. A high-pull J-hook headgear on the lower dental arch was used to prevent further labial inclination of the lower incisors. The total active treatment period was 37 months. The resulting occlusion and a satisfactory facial profile were maintained during a 4-year retention period. Additionally, this treatment did not affect the stomatognathic functions as assessed by the following criteria: range of the incisal path or condylar motion during maximal open-close movement, protrusive excursion, lateral excursion, and the chewing test. In conclusion, extraction of the upper lateral incisors can be an effective treatment choice when the upper lateral incisors are dwarfed, are nonvital, or demonstrate severe malposition. PMID:22908948

Ishihara, Yoshihito; Kuroda, Shingo; Sumiyoshi, Kumi; Takano-Yamamoto, Teruko; Yamashiro, Takashi

2013-03-01

164

[Multi-bed & multi-parameter central monitoring system based on TCP/IP protocol].  

PubMed

Communication is one of the key problems to a central monitoring system. In this paper we put forward a central monitoring system using TCP/IP as the network protocol, Windows NT4.0 as the platform, forming a Intranet in a hospital. We also discussed the communication problem between the bed-side monitoring station and the central monitoring station in detail and then put forward a new protocol--Hospital Central Monitor Protocol (HCMP) based on TCP/IP to transfer monitoring data. It is easy to achieve tele-monitoring through the current communication subsystem. PMID:12583091

Lian, S J; Hu, D K; Zhao, M H; Tang, L H

2000-02-01

165

An Agent-Based Model of Centralized Institutions, Social Network Technology, and Revolution  

PubMed Central

This paper sheds light on the general mechanisms underlying large-scale social and institutional change. We employ an agent-based model to test the impact of authority centralization and social network technology on preference falsification and institutional change. We find that preference falsification is increasing with centralization and decreasing with social network range. This leads to greater cascades of preference revelation and thus more institutional change in highly centralized societies and this effect is exacerbated at greater social network ranges. An empirical analysis confirms the connections that we find between institutional centralization, social radius, preference falsification, and institutional change.

Makowsky, Michael D.; Rubin, Jared

2013-01-01

166

Cadherin-related neuronal receptors in incisor development.  

PubMed

Cadherins are cell adhesion molecules that are critical for tissue development. In this report, we identified members of the cadherin family cadherin-related neuronal receptors (CNRs) 1 and 5 expressed in rat incisors by the differential display method. Quantitative RT-PCR revealed that CNR1 mRNA is expressed in the secretory stage but reduced in the early-maturation stage, while CNR5 mRNA is expressed in both these stages. In situ hybridization showed that strong expression of CNR1 is strong in the secretory stage, but reduced in the early phase and diminished in the late phase of the early-maturation stage. CNR5 mRNA is expressed almost at the same levels in the secretory and in the early phase of the early-maturation stages but is absent in the late phase of the early-maturation stage. Both CNR1 and 5 mRNA are continuously expressed in odontoblasts. Immunohistology showed that CNR proteins are expressed in the secretory and early-maturation stages of ameloblasts, but no protein expression at the late-maturation stage was observed. CNR proteins were continuously expressed in odontoblasts. We found that recombinant CNR1 binds dental epithelial and mesenchymal cells through N-terminal domain EC1 in vitro. These results suggest that CNR1 and CNR5 may play an important role in enamel and dentin formation, probably through cell-cell and/or cell-matrix interactions. PMID:12508039

Fukumoto, E; Sakai, H; Fukumoto, S; Yagi, T; Takagi, O; Kato, Y

2003-01-01

167

A development-based compartmentalization of the Drosophila central brain  

PubMed Central

The neuropile of the Drosophila brain is subdivided into anatomically discrete compartments. Compartments are rich in terminal neurite branching and synapses; they are the neuropile domains in which signal processing takes place. Compartment boundaries are defined by more or less dense layers of glial cells, as well as long neurite fascicles. These fascicles are formed during the larval period when the approximately 100 neuronal lineages that constitute the Drosophila central brain differentiate. Each lineage forms an axon tract with a characteristic trajectory in the neuropile; groups of spatially related tracts congregate into the brain fascicles that can be followed from the larva throughout metamorphosis into the adult stage. In this paper we provide a map of the adult brain compartments and the relevant fascicles defining compartmental boundaries. We have identified the neuronal lineages contributing to each fascicle, which allowed us to directly compare compartments of the larval and adult brain. Most adult compartments can be recognized already in the early larval brain where they form a “protomap” of the later adult compartments. Our analysis highlights the morphogenetic changes shaping the Drosophila brain; the data will be important for studies that link early acting genetic mechanisms to the adult neuronal structures and circuits controlled by these mechanisms.

Pereanu, Wayne; Kumar, Abilasha; Jennett, Arnim; Reichert, Heinrich; Hartenstein, Volker

2010-01-01

168

Ground-based Fourier transform infrared spectroscopy in central Mexico  

NASA Astrophysics Data System (ADS)

Altzomoni is a high altitude station in central Mexico (19.12 N, 98.65 W, 4000 m a.s.l.) for continuous measurements of various atmospheric parameters. It is located within the Izta-Popo National Park and is operated remotely from the UNAM campus. Since May 2012, high resolution solar absorption spectra have been recorded from this site using a FTIR from Bruker (HR120/5) equipped with MCT, InSb and InGaAs detectors and various optical filters. In this contribution we present a detailed description of the measurement site and the instrumental set-up including a record of the instrumental line-shapes (modulation efficiency and phase error) obtained from cell measurements and analyzed with the LINEFIT code. A preliminary analysis of almost two years of spectra recorded at the Altzomoni site resulting in profile retrievals of four NDACC gases O3, CO, HF and HCl is presented. The retrieval code PROFFIT is used and the Averaging Kernels and an error analysis are used to describe the quality of the measurements. The annual cycles in the time series of O3 and CO are presented and discussed, as well as some examples of anomalies due to volcanic gas emissions of HF and HCl are shown. The presented work is part of an effort to certify this station as part of the NDACC international network.

Plaza, Eddy; Stremme, Wolfgang; Bezanilla, Alejandro; Baylon, Jorge; Grutter, Michel; Blumenstock, Thomas; Hase, Frank

2014-05-01

169

Comparison between an Acrylic Splint Herbst and an Acrylic Splint Miniscrew-Herbst for Mandibular Incisors Proclination Control  

PubMed Central

Aim. The aim of this study is to compare dental and skeletal effects produced by an acrylic splint Herbst with and without skeletal anchorage for correction of dental class II malocclusion. Methods. The test group was formed by 14 patients that were treated with an acrylic splint miniscrew-Herbst; miniscrews were placed between mandibular second premolars and first molars; controls also consisted of 14 subjects that were treated with an acrylic splint Herbst and no miniscrews. Cephalometric measurements before and after Herbst treatment were compared. The value of ? for significance was set at 0.05. Results. All subjects from both groups were successfully treated to a bilateral Class I relationship; mean treatment time was 8,1 months in the test group and 7.8 in the controls. Several variables did not have a statistical significant difference between the two groups. Some of the variables, instead, presented a significant difference such as incisor flaring, mandibular bone base position, and skeletal discrepancy. Conclusions. This study showed that the Herbst appliance associated to miniscrews allowed a better control of the incisor flaring with a greater mandibular skeletal effect.

Manni, Antonio; Pasini, Marco; Nuzzo, Claudio; Grassi, Felice Roberto

2014-01-01

170

Lateral incisor agenesis, canine impaction and characteristics of supernumerary teeth in a South European male population  

PubMed Central

Objective: To assess the prevalence of lateral incisor agenesis impacted canines and supernumerary teeth in a young adult male population. Materials and Methods: The panoramic radiographs of 1745 military students (mean age: 18.6 ± 0.52 years) who attended the Center of Aviation Medicine of the Armed Forces of Greece during the period 1997-2011 were initially analyzed for lateral incisor agenesis by two observers. After exclusion of the known orthodontic cases, a subgroup of 1636 examinees (mean age: 18.6 ± 0.44 years) was evaluated for canine impaction and supernumerary teeth. Results: Twenty-eight missing lateral incisors were observed in 22 military students, indicating an incidence of 1.3% in the investigated population. No lateral incisor agenesis was detected in the mandibular arch. A prevalence rate of 0.8% was determined for canine impaction in the sample of young adults. The majority of impacted teeth (86.7%) were diagnosed in the maxillary arch. Thirty-five supernumerary teeth were observed in 24 examinees (prevalence rate: 1.5%). The ratio of supernumerary teeth located in the maxilla versus the mandible was 2.2:1. The most common type of supernumerary tooth was the upper distomolar. Conclusion: The prevalence of lateral incisor agenesis, canine impaction, and supernumerary teeth ranged from 0.8 to 1.5% in the sample of male Greek military students.

Delli, Konstantina; Livas, Christos; Bornstein, Michael M.

2013-01-01

171

Neurogenic potential of dental pulp stem cells isolated from murine incisors  

PubMed Central

Introduction Interest in the use of dental pulp stem cells (DPSC) to enhance neurological recovery following stroke and traumatic injury is increasing following successful pre-clinical studies. A murine model of autologous neural stem cell transplantation would be useful for further pre-clinical investigation of the underlying mechanisms. However, while human-derived DPSC have been well characterised, the neurogenic potential of murine DPSC (mDPSC) has been largely neglected. In this study we demonstrate neuronal differentiation of DPSC from murine incisors in vitro. Methods mDPSC were cultured under neuroinductive conditions and assessed for neuronal and glial markers and electrophysiological functional maturation. Results mDPSC developed a neuronal morphology and high expression of neural markers nestin, ßIII-tubulin and GFAP. Neurofilament M and S100 were found in lower abundance. Differentiated cells also expressed protein markers for cholinergic, GABAergic and glutaminergic neurons, indicating a mixture of central and peripheral nervous system cell types. Intracellular electrophysiological analysis revealed the presence of voltage-gated L-type Ca2+ channels in a majority of cells with neuronal morphology. No voltage-gated Na+ or K+ currents were found and the cultures did not support spontaneous action potentials. Neuronal-like networks expressed the gap junction protein, connexin 43 but this was not associated with dye coupling between adjacent cells after injection of the low-molecular weight tracers Lucifer yellow or Neurobiotin. This indicated that the connexin proteins were not forming traditional gap junction channels. Conclusions The data presented support the differentiation of mDPSC into immature neuronal-like networks.

2014-01-01

172

Randomized, controlled trial of cannabis-based medicine in central pain in multiple sclerosis  

Microsoft Academic Search

Background: Central pain in multiple sclerosis (MS) is common and often refractory to treatment. Methods: We conducted a single-center, 5-week (1-week run-in, 4-week treatment), randomized, double-blind, placebo-controlled, parallel-group trial in 66 patients with MS and central pain states (59 dysesthetic, seven painful spasms) of a whole-plant cannabis-based medicine (CBM), containing delta-9-tetrahydrocannabinol:cannabidiol (THC:CBD) delivered via an oromu- cosal spray, as adjunctive

David J. Rog; Turo J. Nurmikko; Tim Friede; Carolyn A. Young

2005-01-01

173

Web-Based Training Improves Knowledge about Central Line Bloodstream Infections  

PubMed Central

A Web-based training course with embedded video clips for reducing central line–associated bloodstream infections (CLABSIs) was evaluated and shown to improve clinician knowledge and retention of knowledge over time. To our knowledge, this is the first study to evaluate Web-based CLABSI training as a stand-alone intervention.

Comer, Angela; Harris, Anthony D.; Shardell, Michelle; Braun, Barbara; Belton, Beverly M.; Wolfsthal, Susan D.; Dembry, Louise-Marie; Jacob, Jesse T.; Price, Connie; Sulis, Carol; Chu, Eugene S.; Xiao, Yan

2012-01-01

174

Gemination of a Permanent Lateral Incisor- A Case Report with Special Emphasis on Management  

PubMed Central

The purpose of this case report is to describe the successful endodontic treatment and surgical management of a unesthetic geminated permanent maxillary lateral incisor tooth. Geminated maxillary incisor clinically revealed bifid crown with coronal groove and intraoral periapical radiograph showing radiolucent lesion with sclerotic border. orthograde root canal treatment was performed. surgery was done by reflecting limited thickness mucoperiosteal flap, cyst enucleated, root end resected and retrograde filling done using mineral trioxide aggregate. During the follow up examination, post operative intra oral periapical radiographs revealed healing of periapical lesion. How to cite this article: Sharada H L, Deo B, Briget B. Gemination of a Permanent Lateral Incisor - A Case Report with Special Emphasis on Management. J Int Oral Health 2013; 5(2):55-59.

Sharada, H L; Deo, Bharathi; Briget, Biji

2013-01-01

175

Gemination of a permanent lateral incisor- a case report with special emphasis on management.  

PubMed

The purpose of this case report is to describe the successful endodontic treatment and surgical management of a unesthetic geminated permanent maxillary lateral incisor tooth. Geminated maxillary incisor clinically revealed bifid crown with coronal groove and intraoral periapical radiograph showing radiolucent lesion with sclerotic border. orthograde root canal treatment was performed. surgery was done by reflecting limited thickness mucoperiosteal flap, cyst enucleated, root end resected and retrograde filling done using mineral trioxide aggregate. During the follow up examination, post operative intra oral periapical radiographs revealed healing of periapical lesion. Key words:Gemination, Periapical Cyst, Retrograde Filling. How to cite this article: Sharada H L, Deo B, Briget B. Gemination of a Permanent Lateral Incisor - A Case Report with Special Emphasis on Management. J Int Oral Health 2013; 5(2):55-59. PMID:24155591

Sharada, H L; Deo, Bharathi; Briget, Biji

2013-04-01

176

Alpha11 beta1 integrin-dependent regulation of periodontal ligament function in the erupting mouse incisor  

Microsoft Academic Search

The fibroblast integrin 111 is a key receptor for fibrillar collagens. To study the potential function of 11 in vivo, we generated a null allele of the 11 gene. Integrin 11\\/ mice are viable and fertile but display dwarfism with increased mortality, most probably due to severely defective incisors. Mutant incisors are characterized by disorganized periodontal ligaments, whereas molar ligaments

Svetlana N. Popova; Malgorzata Barczyk; Carl-Fredrik Tiger; Wouter Beertsen; Paola Zigrino; Attila Aszodi; Nicolai Miosge; Erik Forsberg; Donald Gullberg

2007-01-01

177

An examination of the effects of levelingwith nickel titanium rectangular arch wires combined with torqued incisor brackets  

Microsoft Academic Search

Leveling the curve of Spee with sequential round cross-section arch wires characteristically results in incisor proclination. To prevent this, the use of low modulus, rectangular cross-section arch wires combined with torqued incisor brackets has been recommended by some clinicians. Clinical data were analyzed to determine whether this is the case. It showed that proclination does occur at a lesser angle

Stanley Braun

2001-01-01

178

A Retrospective Assessment of Zinc Oxide-Eugenol Pulpectomies in Vital Maxillary Primary Incisors Successfully Restored With Composite Resin Crowns  

Microsoft Academic Search

Purpose: The purpose of this retrospective study was to evaluate, via clinical and radio- graphic assessments, the treatment outcome of zinc oxide-eugenol (ZOE) pulpectomies performed in vital maxillary primary incisors successfully restored with composite resin crowns. Methods: Pulpectomized vital primary incisors were treated by a uniformed technique, filled with ZOE paste, and successfully restored with composite resin crowns. Those that

Robert E. Primosch; Anissa Ahmadi; Barry Setzer

2005-01-01

179

Detecting local community structures in complex networks based on local degree central nodes  

NASA Astrophysics Data System (ADS)

Detecting local communities in real-world graphs such as large social networks, web graphs, and biological networks has received a great deal of attention because obtaining complete information from a large network is still difficult and unrealistic nowadays. In this paper, we define the term local degree central node whose degree is greater than or equal to the degree of its neighbor nodes. A new method based on the local degree central node to detect the local community is proposed. In our method, the local community is not discovered from the given starting node, but from the local degree central node that is associated with the given starting node. Experiments show that the local central nodes are key nodes of communities in complex networks and the local communities detected by our method have high accuracy. Our algorithm can discover local communities accurately for more nodes and is an effective method to explore community structures of large networks.

Chen, Qiong; Wu, Ting-Ting; Fang, Ming

2013-02-01

180

Simulating certain aspects of hypogravity: Effects on the mandibular incisors of suspended rats (PULEH model)  

NASA Technical Reports Server (NTRS)

The effect of a hypogravity simulating model on the rate of mandibular incisor formation, dentinogenesis and, amelogenesis in laboratory rats was studied. The model is the partial unloading by elevating the hindquarters. In this system, rat hindquarters are elevated 30 to 40 deg from the cage floors to completely unload the hindlimbs, but the animals are free to move about using their forelimbs. This model replicates the fluid sift changes which occur during the weightlessness of spaceflight and produces an osteopenia in the weight bearing skeletons. The histogenesis and/or mineralization rates of the mandibular incisor during the first 19d of PULEH in young growing rats are recorded.

Simmons, D. J.; Winter, F.; Morey-Holton, E. R.

1984-01-01

181

To open or to close space--that is the missing lateral incisor question.  

PubMed

Developmentally absent permanent maxillary lateral incisors may be associated with several problems. The decision whether to open or to close the space should involve the patient/parent, orthodontist and restorative dentist. To optimize function and aesthetics, space should be opened using fixed appliances to accommodate an appropriate prosthesis. Implant-retained crowns offer several advantages, although adhesive bridges are more appropriate in certain circumstances. Removable partial dentures may be necessary in some instances. Where space opening is not feasible, practical or desirable, any residual spacing can be closed using fixed appliances and the permanent maxillary canines modified to resemble lateral incisors. PMID:15739660

Savarrio, Lee; McIntyre, Grant T

2005-01-01

182

Rehabilitation of molar-incisor hypomineralization (MIH) complicated with localized tooth surface loss: a case report.  

PubMed

Molar-incisor hypomineralization (MIH) is a developmental enamel hypomineralized condition characteristically involving the first permanent molars and sometimes also the incisors. The affected teeth are predisposed to tooth surface loss (TSL) which may not only compromise the esthetics and function but also endanger the pulp and longevity of the teeth. This report describes the management of a patient with MIH complicated with localized TSL and lack of occlusal clearance due to dentoalveolar compensation. The atypical TSL pattern involved all anterior teeth and required the placement of Dahl appliances on both arches. PMID:24634901

Lam, Walter Y H; Ho, Edward H T; Pow, Edmond H N

2014-05-01

183

Iatrogenic absence of maxillary canines: Bolton discrepancy treated with mandibular incisor extraction.  

PubMed

This case report describes the orthodontic treatment of an adult patient with iatrogenic absence of the maxillary canines, moderate maxillary and severe mandibular dental crowding, a Bolton discrepancy with a large mandibular anterior excess, a maxillary right lateral incisor crossbite, and Angle Class II molar relationships. The treatment consisted of fixed appliance therapy, mandibular incisor extraction, tooth bleaching, and dental recontouring. This method of treatment maintained the patient's good facial appearance, improved the dental esthetics, and provided a good functional occlusion, eliminating the arch length and Bolton discrepancies and providing a good outcome with minimal undesirable effects. PMID:23631973

Simão, Tassiana Mesquita; Valladares-Neto, José; Rino-Neto, José; de Paiva, João Batista

2013-05-01

184

Glass-fiber reinforced composite in management of avulsed central incisor: a case report.  

PubMed

Reimplantation failure of avulsed anterior tooth in an adolescent patient requires removal of the failed tooth and consideration of restorative options. These options may include a removable partial denture, conventional 3-unit fixed partial denture, implant, or a resin-bonded appliance with a metal substructure (Maryland bridge). The glass-fiber reinforced composite material (everSTICK, StickTech Ltd, Turku, Finland) offers a restorative solution that is conservative and esthetic when compared to other restorations. Advantages include reduction of cost compared to conventional bridges, saving of time, elimination of second visit, ease of application, absence of metal allergy, ease of cleaning, and naturalness of feel. Its limitations include occlusal factors, and the presence of unsuitable abutment teeth. Another traditional contraindication is the presence of diastemas, which may limit the potential esthetic gains. This case of an 11-year-old girl, addresses the indications, preparation guidelines, and restorative procedures for an everSTICK bridge. PMID:15272660

Aydin, M Yalçin; Kargül, Betül

2004-01-01

185

Endodontic Treatment and Esthetic Management of a Geminated Central Incisor Bearing a Talon Cusp  

PubMed Central

Gemination with talon cusps is an uncommon morphologic dental anomaly, characterized by the formation of clinically wide tooth that can cause significant aesthetic and clinical problems including esthetic impairment, pain, caries susceptibility, and tooth crowding. These morphological dental anomalies have specific treatment needs due to the abnormal morphology and need virtuous radiologic diagnosis. Multidisciplinary approach can supply success of the treatment plan that can provide esthetic and occlusal requirements. In this case report, the multidisciplinary approach for the treatment of geminated tooth with talon cusp is presented with the clinical and radiographic findings.

Tar?m Ertas, Elif; Y?rcal? At?c?, Meral; Arslan, Hakan; Yasa, Bilal; Ertas, Huseyin

2014-01-01

186

Endodontic management of an unusual foreign body in a maxillary central incisor.  

PubMed

The discovery of foreign bodies in the teeth is often diagnosed accidentally. It is commonly seen in children. These foreign objects may act as a potential source of infection and may later lead to a painful condition. Detailed case history, clinical and radiographic examinations are necessary to come to a conclusion about the nature, size, and location of the foreign body, and the difficulty involved in its retrieval. This paper discusses the types of foreign objects found in and around the teeth and reports an unusual case of a stapler pin in the root canal of a tooth, its retrieval, and associated management of the involved teeth. PMID:24082582

Chand, Keerthi; Joesph, Sam; Varughese, Jolly Mary; Nair, Mali G; Prasanth, Santhosh

2013-09-01

187

CENTRALIZED VERSUS MARKET-BASED APPROACHES TO MOBILE TASK ALLOCATION PROBLEM: STATE-OF-THE- ART  

Microsoft Academic Search

Centralized approach has been adopted for finding solutions to resource allocation problems (RAPs) in many real-life applications. On the other hand, market-based approach has been proposed as an alternative to solve the problem due to recent advancement in ICT technologies. In spite of the existence of some efforts to review the pros and cons of each approach in RAPs, the

Karim Al-Yafi; Habin Lee

2009-01-01

188

Evaluation of the central heating plant operation at Malmstrom Air Force Base, MT. Final report  

Microsoft Academic Search

In 1983, a new coal-fired central heating plant was built for Malmstrom Air Force Base (MAFB), MT, to replace the existing poorly operating system and provide for increased heating requirements. Although the generators had been fired intermittently with coal, an unofficial test in March 1986 failed due to plugging in the convective section. To determine the cause of the plugging,

M. J. Savoie; J. Davidson; J. Northrup; T. Ask; C. Schmidt

1995-01-01

189

School-Based and Centrally Directed Curriculum Development--The Uneasy Middle Ground.  

ERIC Educational Resources Information Center

Charts development and describes features of multidisciplinary health studies course emphasizing experiential learning being introduced as part of Munn and Dunning development program. Suggests methods for easing tensions generated when aspects of school-based development are introduced into centrally controlled curriculum change to develop…

Simpson, Mary

1986-01-01

190

Cultivating Urban Naturalists: Teaching Experiential, Place-Based Learning through Nature Journaling in Central Park  

ERIC Educational Resources Information Center

Preservice educators engaged in experiential, place-based learning through a semester-long assignment in which they observed a specific place in Central Park in Manhattan, New York, and kept a nature journal. The assignment was organized around two pivotal elements: direct, sensory experience and time in place. Both elements added vital dimensions…

Warkentin, Traci

2011-01-01

191

Spatial and Seasonal Variability of Base Flow in the Verde Valley, Central Arizona, 2007 and 2011.  

National Technical Information Service (NTIS)

Synoptic base-flow surveys were conducted on streams in the Verde Valley, central Arizona, in June 2007 and February 2011 by the U.S. Geological Survey (USGS), in cooperation with the Verde River Basin Partnership, the Town of Clarkdale, and Yavapai Count...

B. D. Garner D. J. Bills

2012-01-01

192

Zero Based Staffing/Services Analysis for the Central State University Library.  

ERIC Educational Resources Information Center

Zero Based Staffing/Services (ZBS/S)--a management tool designed to portray the relationship between the people or staff of an agency and the services they perform--was used in this study to inventory library services and staffing at the Central State University Library and provide a long-range planning analysis for library and university…

Lolley, John, Ed.

193

Centralization vs. Decentralization Issues in Internet-based Knowledge Management Systems: Experiences from Expert Recommender Systems  

Microsoft Academic Search

In this paper we report on the issues pertaining to centralized vs. decentralized architectures that we en- countered at various points of our research on a particu- lar Internet-based knowledge management and sharing system, namely expert finders\\/recommenders. First, we briefly describe and analyze our design experiences in expert recommender systems, emphasizing the architec- tural challenges and decisions. Then we extrapolate

Dawit Yimam; Alfred Kobsa

194

New Structural Interpretation of the Central Confusion Range, Western Utah, Based On Balanced Cross Sections  

Microsoft Academic Search

The Confusion Range is a topographically low mountain range in the Basin and Range of west-central Utah, located east of and in the hanging wall of the Snake Range core complex. Previous workers have used a gravity sliding model to interpret the Confusion Range as a large structural trough or synclinorium (e.g. Hose, 1977). Based on existing mapping (Hose, 1965;

D. Yezerski; D. C. Greene

2009-01-01

195

[The zero-curve--variability of the functional contact area of upper incisors].  

PubMed

The palatal contact area of upper incisors is an essential factor in the Krüger and Kubein occlusion conception. A long-term study at ideal plaster models suggested no significant alterations of the zero-curve in dependence on changing overbite. PMID:2132113

Haffner, T; Reinhardt, H; Steindorf, A

1990-12-01

196

Histology of primary incisor enamel in children with early onset celiac disease  

Microsoft Academic Search

The manifestations of celiac disease are a result of nutri- tional malabsorption. An early onset of such malabsorption may jeopardize the primary enamel which is not mineralized. Prepared sections of 10 primary incisors from 10 children with early onset celiac disease were examined using polarized light microscopy to determine if enamel defects were present. Study of the tooth sections dry

Daniel Raether

1988-01-01

197

Evaluation of Canal Morphology at Different Levels of Root Resection in Mandibular Incisors.  

National Technical Information Service (NTIS)

One hundred randomly selected mandibular incisors were examined to assess the prevalence and location of two canals and to describe the canal anatomy that may be encountered during apical surgery. The roots were resected at 1, 2, and 3mm apical sections s...

M. J. Mauger

1997-01-01

198

Effects of incisor-cutting on muricidal behavior induced by olfactory bulbectomy in rats  

Microsoft Academic Search

Muricidal behavior in rats is composed of two main components, attacking and killing performance. Since a large number of mice could be killed by rats during behavioral experiments, research has been limited in the past decade possibly because of ethical considerations. In preliminary studies, we found that the rat incisors play a key role in muricidal behavior in rats, so,

Hung Hsuchou; Ying-Jui Ho; Hao-Ai Shui; Mei-Yun Tai; Kuang-Ho Chen; Yuan-Feen Tsai

2002-01-01

199

Iodopolatinate visualization of phospholipids in rat incisor predentine and dentine, compared with malachite green aldehyde  

Microsoft Academic Search

The iodoplatinate (IP) reaction, a selective method for visualization of phospholipids, was applied to the predentine and dentine of rat incisors and compared with malachite green aldehyde (MG) fixation\\/staining. Spot tests indicated (1) that IP specifically stains phospholipids, but not amino acids, displaying as do phospholipids, quaternary ammonium groups; and (2) phosphatidylserine and sphingomyelin were also stained by MGA. Although

L. Vermelin; D. Septier; M. Goldberg

1994-01-01

200

The importance of incisor positioning in the esthetic smile: The smile arc  

Microsoft Academic Search

The smile arc is defined as the relationship of the curvature of the incisal edges of the maxillary incisors and canines to the curvature of the lower lip in the posed smile. The ideal smile arc has the maxillary incisal edge curvature parallel to the curvature of the lower lip. Evaluation of anterior smile esthetics must include both static and

David M. Sarver

2001-01-01

201

An Evolutionarily Conserved Enhancer Regulates Bmp4 Expression in Developing Incisor and Limb Bud  

PubMed Central

To elucidate the transcriptional regulation of Bmp4 expression during organogenesis, we used phylogenetic footprinting and transgenic reporter analyses to identify Bmp4 cis-regulatory modules (CRMs). These analyses identified a regulatory region located ?46 kb upstream of the mouse Bmp4 transcription start site that had previously been shown to direct expression in lateral plate mesoderm. We refined this regulatory region to a 396-bp minimal enhancer, and show that it recapitulates features of endogenous Bmp4 expression in developing mandibular arch ectoderm and incisor epithelium during the initiation-stage of tooth development. In addition, this enhancer directs expression in the apical ectodermal ridge (AER) of the developing limb and in anterior and posterior limb mesenchyme. Transcript profiling of E11.5 mouse incisor dental lamina, together with protein binding microarray (PBM) analyses, allowed identification of a conserved DNA binding motif in the Bmp4 enhancer for Pitx homeoproteins, which are also expressed in the developing mandibular and incisor epithelium. In vitro electrophoretic mobility shift assays (EMSA) and in vivo transgenic reporter mutational analyses revealed that this site supports Pitx binding and that the site is necessary to recapitulate aspects of endogenous Bmp4 expression in developing craniofacial and limb tissues. Finally, Pitx2 chromatin immunoprecipitation (ChIP) demonstrated direct binding of Pitx2 to this Bmp4 enhancer site in a dental epithelial cell line. These results establish a direct molecular regulatory link between Pitx family members and Bmp4 gene expression in developing incisor epithelium.

O'Connell, Daniel J.; Aboukhalil, Anton; Li, Xiao; Choe, Sung E.; Ho, Joshua W. K.; Turbe-Doan, Annick; Robertson, Erin A.; Olsen, Bjorn R.; Bulyk, Martha L.; Amendt, Brad A.; Maas, Richard L.

2012-01-01

202

Organic and inorganic content of fluorotic rat incisors measured by FTIR spectroscopy  

Microsoft Academic Search

Details on how fluoride interferes in enamel mineralization are still controversial. Therefore, this study aimed at analyzing the organic contents of fluorosis-affected teeth using Fourier Transformation Infrared spectroscopy. To this end, 10 male Wistar rats were divided into two groups: one received 45ppm fluoride in distilled water for 60 days; the other received distilled water only. Then, the lower incisors

Isabel Maria Porto; Regina Aparecida Saiani; K. L. Andrew Chan; Sergei G. Kazarian; Raquel Fernanda Gerlach; Luciano Bachmann

2010-01-01

203

A Traffic Reduction Method for Centralized RSSI-Based Location Estimation in Wireless Sensor Networks  

NASA Astrophysics Data System (ADS)

In a centralized localization scenario, the limited throughput of the central node constrains the possible number of target node locations that can be estimated simultaneously. To overcome this limitation, we propose a method which effectively decreases the traffic load associated with target node localization, and therefore increases the possible number of target node locations that can estimated simultaneously in a localization system based on received signal strength indicator (RSSI) and maximum likelihood estimation. Our proposed method utilizes a threshold which limits the amount of forwarded RSSI data to the central node. As the threshold is crucial to the method, we further propose a method to theoretically determine its value. We experimentally verified the proposed method in various environments and the experimental results revealed that the method can reduce the load by 32-64% without significantly affecting the estimation accuracy.

Zemek, Radim; Hara, Shinsuke; Yanagihara, Kentaro; Kitayama, Ken-Ichi

204

Prevalence and Incidence of Gemination and Fusion in Maxillary Lateral Incisors in Odisha population and Related Case Report  

PubMed Central

Aim: A survey was conducted to analyze the prevalence and incidence of dental anomalies in relation to maxillary lateral incisors in the Odisha population. A multidisciplinary approach for aesthetic management of a geminated tooth is described. Material and Methods: A total of 1062 subject, aged between 15-30 years (724 males and 338 Females) were randomly screened at Institute of Dental Sciences, Bhubaneswar, Odisha India. Each subject was examined clinically and radiovisuographically for dental anomalies in relation to maxillary lateral incisors. In the related case described, endodontic management and aesthetic correction of geminated maxillary lateral incisors was done. Results: Five dental anomalies i.e. gemination, fusion, missing lateral incisors (both unilateral and bilateral), peg shaped incisors (unilateral and bilateral), and dens in dente were observed. Anomalies found were Peg shaped; 2.82%, Missing;1.88%, Gemination;0.28%, Fusion;0.18% and Dens in Dente;0.18%. Conclusion: Comparison of these results with that of other studies indicated that anomalies in lateral incisors occur at different frequencies among various countries and communities in the world. In the case since maxillary lateral incisors are in the aesthetic zone, recognizing these anomalies will facilitate a successful treatment.

G., Shashirekha; Jena, Amit

2013-01-01

205

Differentiating Obstructive from Central and Complex Sleep Apnea Using an Automated Electrocardiogram-Based Method  

PubMed Central

Study Objectives: Complex sleep apnea is defined as sleep disordered breathing secondary to simultaneous upper airway obstruction and respiratory control dysfunction. The objective of this study was to assess the utility of an electrocardiogram (ECG)-based cardiopulmonary coupling technique to distinguish obstructive from central or complex sleep apnea. Design: Analysis of archived polysomnographic datasets. Setting: A laboratory for computational signal analysis. Interventions: None. Measurements and Results: The PhysioNet Sleep Apnea Database, consisting of 70 polysomnograms including single-lead ECG signals of approximately 8 hours duration, was used to train an ECG-based measure of autonomic and respiratory interactions (cardiopulmonary coupling) to detect periods of apnea and hypopnea, based on the presence of elevated low-frequency coupling (e-LFC). In the PhysioNet BIDMC Congestive Heart Failure Database (ECGs of 15 subjects), a pattern of “narrow spectral band” e-LFC was especially common. The algorithm was then applied to the Sleep Heart Health Study–I dataset, to select the 15 records with the highest amounts of broad and narrow spectral band e-LFC. The latter spectral characteristic seemed to detect not only periods of central apnea, but also obstructive hypopneas with a periodic breathing pattern. Applying the algorithm to 77 sleep laboratory split-night studies showed that the presence of narrow band e-LFC predicted an increased sensitivity to induction of central apneas by positive airway pressure. Conclusions: ECG-based spectral analysis allows automated, operator-independent characterization of probable interactions between respiratory dyscontrol and upper airway anatomical obstruction. The clinical utility of spectrographic phenotyping, especially in predicting failure of positive airway pressure therapy, remains to be more thoroughly tested. Citation: Thomas RJ; Mietus JE; Peng CK; Gilmartin G; Daly RW; Goldberger AL; Gottlieb DJ. Differentiating obstructive from central and complex sleep apnea using an automated electrocardiogram-based method. SLEEP 2007;30(12):1756-1769.

Thomas, Robert Joseph; Mietus, Joseph E.; Peng, Chung-Kang; Gilmartin, Geoffrey; Daly, Robert W.; Goldberger, Ary L.; Gottlieb, Daniel J.

2007-01-01

206

Automatic target recognition of radar HRRP based on high order central moments features  

Microsoft Academic Search

The paper addresses the problem of target recognition using High-resolution Radar Range Profiles (HRRP). A novel approach\\u000a of feature extraction and dimension reduction based on extended high order central moments is proposed in order to reduce\\u000a the dimension of range profiles. Features extracted from radar HRRPs are normalized and smoothed, and then comparative analysis\\u000a of the similar approaches is done.

Luo Si Li Shaohong; Shaohong Li

2009-01-01

207

A multidimensional magnetohydrodynamics code based on semidiscrete central WENO and PPM schemes  

NASA Astrophysics Data System (ADS)

We present a multidimensional magnetohydrodynamics code based on semidiscrete central Godunov-type schemes and high order weighted essentially non-oscillatory data reconstruction and incorporate elements of the piecewise parabolic method into the reconstruction schemes. This algorithm avoids spectral decomposition into characteristic waves and is easily implemented. We have implemented this algorithm and carried out one and two dimensional tests, which verifies that this code can achieve the accuracy and efficiency to solve the astrophysical problems.

Yang, Xiaohong; Li, Qixiu

2009-01-01

208

Survival rate and fracture strength of incisors restored with different post and core systems after exposure in the artificial mouth.  

PubMed

The survival rate and fracture resistance of 40 decapitated endodontically treated maxillary central incisors using four different post and core systems covered with all-ceramic copings was evaluated after exposure in the artificial mouth. Ten samples of the following post and core systems were investigated: high precious metal post (Permador) and core (Olympia) (A), zirconia post (Cerapost) with a pre-fabricated bonded ceramic core (Ceracap) (B), resin-ceramic post (experimental) with a pre-fabricated bonded ceramic core (Ceracap(R)) (C) and a zirconia post (Cerapost) with a custom made ceramic core (Cosmo Ingots) (D). The all-ceramic copings (Procera) were cemented using Panavia TC. The survival rates after 1 200 000 cycles in the artificial mouth are as follows: 90% (A), 80% (B), 60% (C) and 100% (D). The results of the means and standard deviations (s.d.) of the fracture resistance during static loading are: 1270 +/- 312.5 (A), 1494.5 +/- 333.5 (B), 1146.7 +/- 182.6 (C) and 463.3 +/- 46.2 (D). There are statistically significant differences between all groups with the exception of A and B, and A and C (Wilcoxon test). None of the zirconia posts with custom made ceramic cores covered with all-ceramic copings fractured during dynamic loading in the artificial mouth. The mean fracture strength during static loading was less favourable than that of groups A, B and C but above the clinical necessary level. PMID:11298259

Strub, J R; Pontius, O; Koutayas, S

2001-02-01

209

Evaluation of the Effect of Different Ferrule Designs on Fracture Resistance of Maxillary Incisors Restored with Bonded Posts and Cores  

PubMed Central

Introduction: In cases of severe hard tissue loss, 2 mm circumferential ferrule is difficult to achieve. So in these cases we should use different ferrule designs. This in vitro study investigated the effect of different ferrule designs on the fracture resistance of teeth restored with bonded post and cores. Materials and Methods: Forty freshly-extracted central incisors were endodontically treated. The teeth were randomly divided into four groups; group 1 were teeth with 2 mm circumferential ferrule above the CEJ, group 2 were teeth with 2 mm ferrule only on the palatal side of the teeth, group 3 consisted of teeth with 2 mm ferrule only on the facial side and group 4 were teeth with 2 mm ferrule on the palatal and facial side of teeth with interproximal concavities. All teeth were restored with fiber posts and composite cores. The specimen was mounted on a universal testing machine and compressive load was applied to the long axis of the specimen until failure occurred. Results: The fracture resistance was 533.79 ± 232.28 in group 1, 634.75± 133.35 in group 2, 828.90 ±118.27 in group 3 and 678.78± 160.20 in group 4. The post hoc analysis showed statistically significant difference between groups 1 and 3. Conclusions: The results of this in vitro study showed that facial ferrule increases the fracture resistance of endodontically treated teeth restored with bonded post and cores.

Mahdavi Izadi, Z.; Jalalian, E.; Eyvaz Ziaee, A.; Zamani, L.; Javanshir, B.

2010-01-01

210

Development of a Physiologically-Based Pharmacokinetic Model of the Rat Central Nervous System  

PubMed Central

Central nervous system (CNS) drug disposition is dictated by a drug’s physicochemical properties and its ability to permeate physiological barriers. The blood–brain barrier (BBB), blood-cerebrospinal fluid barrier and centrally located drug transporter proteins influence drug disposition within the central nervous system. Attainment of adequate brain-to-plasma and cerebrospinal fluid-to-plasma partitioning is important in determining the efficacy of centrally acting therapeutics. We have developed a physiologically-based pharmacokinetic model of the rat CNS which incorporates brain interstitial fluid (ISF), choroidal epithelial and total cerebrospinal fluid (CSF) compartments and accurately predicts CNS pharmacokinetics. The model yielded reasonable predictions of unbound brain-to-plasma partition ratio (Kpuu,brain) and CSF:plasma ratio (CSF:Plasmau) using a series of in vitro permeability and unbound fraction parameters. When using in vitro permeability data obtained from L-mdr1a cells to estimate rat in vivo permeability, the model successfully predicted, to within 4-fold, Kpuu,brain and CSF:Plasmau for 81.5% of compounds simulated. The model presented allows for simultaneous simulation and analysis of both brain biophase and CSF to accurately predict CNS pharmacokinetics from preclinical drug parameters routinely available during discovery and development pathways.

Badhan, Raj K. Singh; Chenel, Marylore; Penny, Jeffrey I.

2014-01-01

211

Surgical resection technique of a fused supernumerary lateral incisor: a clinical report and review of the literature.  

PubMed

This case report presents the surgical and restorative management of a fused supernumerary left lateral incisor. The diagnosis was confirmed using conventional radiographs and CT. The case report discusses the value of CT for evaluation of the root relationships and describes the varied morphology associated with supernumerary incisors, the surgical resection technique, partial pulpotomy, and restoration with composite resin after mechanical exposure of the remaining tooth's pulp. PMID:22782063

Beier, Ulrike Stephanie; Dumfahrt, Herbert; Widmann, Gerlig; Puelacher, Wolfgang

2012-01-01

212

Carbonic anhydrase isozyme II immunoreactivity in the mechanoreceptive Ruffini endings of the periodontal ligament in rat incisor  

Microsoft Academic Search

The present study describes the distribution of carbonic anhydrase isozymeII (CAII) in the lingual periodontal ligament of the rat incisor. Some thick nerve fibers in the nerve bundle displayed CAII-like immunoreactivity (LI) as well as non-neuronal elements such as osteoclasts. At the alveolar half of the lingual periodontal ligament of the incisor, thick CAII-like immunoreactive (-IR) nerve fibers showed a

Kanako Ochi; Satoshi Wakisaka; Suk Hyun Youn; Kooji Hanada; Takeyasu Maeda

1998-01-01

213

Calretinin-like immunoreactivity in the Ruffini endings, slowly adapting mechanoreceptors, of the periodontal ligament of the rat incisor  

Microsoft Academic Search

The distribution and ultrastructural localization of calretinin (CR)-like immunoreactivity (-LI) were investigated in the lingual periodontal ligament of rat incisors. Some thick nerve fibers within the nerve bundle displayed CR-LI; these CR-like immunoreactive (-IR) nerve fibers entered the alveolar half of the lingual periodontal ligament of the incisor where dendritic terminal arborization was exhibited. Thin and beaded CR-IR nerve fibers

Kanako Ochi; Satoshi Wakisaka; Suk Hyun Youn; Kooji Hanada; Takeyasu Maeda

1997-01-01

214

Sema3A chemorepellant regulates the timing and patterning of dental nerves during development of incisor tooth germ.  

PubMed

Semaphorin 3A (Sema3A) axon repellant serves multiple developmental functions. Sema3A mRNAs are expressed in epithelial and mesenchymal components of the developing incisor in a dynamic manner. Here, we investigate the functions of Sema3A during development of incisors using Sema3A-deficient mice. We analyze histomorphogenesis and innervation of mandibular incisors using immunohistochemistry as well as computed tomography and thick tissue confocal imaging. Whereas no apparent disturbances in histomorphogenesis or hard tissue formation of Sema3A (-/-) incisors were observed, nerve fibers were prematurely seen in the presumptive dental mesenchyme of the bud stage Sema3A (-/-) tooth germ. Later, nerves were ectopically present in the Sema3A (-/-) dental papilla mesenchyme during the cap and bell stages, whereas in the Sema3A (+/+) mice the first nerve fibers were seen in the pulp after the onset of dental hard tissue formation. However, no apparent topographic differences in innervation pattern or nerve fasciculation were seen inside the pulp between postnatal and adult Sema3A (+/+) or Sema3A (-/-) incisors. In contrast, an abnormally large number of nerves and arborizations were observed in the Sema3A (-/-) developing dental follicle target field and periodontium and, unlike in the wild-type mice, nerve fibers were abundant in the labial periodontium. Of note, the observed defects appeared to be mostly corrected in the adult incisors. The expressions of Ngf and Gdnf neurotrophins and their receptors were not altered in the Sema3A (-/-) postnatal incisor or trigeminal ganglion, respectively. Thus, Sema3A is an essential, locally produced chemorepellant, which by creating mesenchymal exclusion areas, regulates the timing and patterning of the dental nerves during the development of incisor tooth germ. PMID:24752460

Shrestha, Anjana; Moe, Kyaw; Luukko, Keijo; Taniguchi, Masahiko; Kettunen, Paivi

2014-07-01

215

Fixed retention of congenitally missing maxillary lateral incisors using a chairside, prefabricated fiber-reinforced composite bridge.  

PubMed

Adolescents with congenitally missing lateral incisors require an interim space maintainer to restore function and esthetics before craniofacial growth is complete and an endosseous implant can be placed. This article presents 2 patients, each with a missing lateral incisor, who underwent orthodontic therapy. A chairside, prefabricated fiber-reinforced composite bridge was used as a fixed space maintainer after the appliances were removed. PMID:19146016

Uribe, Flavio; Meiers, Jonathan C; Nanda, Ravindra

2008-01-01

216

Non-Syndromic Bilateral Supplemental Maxillary Lateral Incisors: A Rare Case  

PubMed Central

Supernumerary teeth or hyperdontia are defined as the teeth that exceeds the normal dental formula, regardless of their location and morphology. A supernumerary tooth is a developmental anomaly and it has been argued to arise from multiple aetiologies. Supernumerary teeth with orthodox shapes and sizes, that resemble the normal dentition are called ‘supplemental teeth’. The supplemental teeth are often overlooked because of their normal shapes and sizes. Supplemental lateral incisors are rare and bilateral cases are even rarer, with only two cases being reported in the literature till date. Therefore, we are describing a rare case of non–syndromic, bilateral, supplemental, maxillary, lateral incisors and we have discussed the management of supernumerary teeth.

Nagpal, Ajay; Hans, Manoj Kumar; Shetty, Shashit; Kaur, Navpreet; Kumar, Sunil

2013-01-01

217

Non-syndromic bilateral supplemental maxillary lateral incisors: a rare case.  

PubMed

Supernumerary teeth or hyperdontia are defined as the teeth that exceeds the normal dental formula, regardless of their location and morphology. A supernumerary tooth is a developmental anomaly and it has been argued to arise from multiple aetiologies. Supernumerary teeth with orthodox shapes and sizes, that resemble the normal dentition are called 'supplemental teeth'. The supplemental teeth are often overlooked because of their normal shapes and sizes. Supplemental lateral incisors are rare and bilateral cases are even rarer, with only two cases being reported in the literature till date. Therefore, we are describing a rare case of non-syndromic, bilateral, supplemental, maxillary, lateral incisors and we have discussed the management of supernumerary teeth. PMID:24086923

Nagpal, Ajay; Hans, Manoj Kumar; Shetty, Shashit; Kaur, Navpreet; Kumar, Sunil

2013-08-01

218

Ageing horses by an examination of their incisor teeth: an (im)possible task?  

PubMed

It is generally considered that the age of a horse can be determined by examining its incisor teeth. However, the criteria used to determine age from dental configurations differ widely. The existence of this variety of rules and guidelines was the challenge for the present examination. Detailed descriptions of the incisor teeth of 212 horses of registered age were recorded and the results were compared with the age criteria of various authors. The time at which teeth were shed and the appearance of dental stars seemed to be more reliable features than the disappearance of the cups. The disappearance of the marks occurred four years later than usually stated. Other criteria, such as the presence of the seven-year notch and Galvayne's groove, were too variable and inconsistent to be reliable for the determination of age. PMID:8730689

Muylle, S; Simoens, P; Lauwers, H

1996-03-30

219

Three-dimensional imaging cone bean computer tomography technology: an update and case report of an impacted incisor in a mixed dentition patient.  

PubMed

The current 3-dimensional (3-D) technology termed "cone beam computer tomography" (CBCT) provides accurate 3-D anatomical image data similar to medical computerized tomography but at a lower cost and dose. CBCT has been suggested to be used in cases of supernumeraries because it yields accurate 3-D information relative to the orientation, sagittal position, local disorders, and neighboring anatomic structures. The purposes of this article were to: present the available 3-D imaging technology; and report the case of a patient in the late mixed dentition with a maxillary supernumerary tooth and an impacted central incisor. The use of a CBCT appears to be favorable as a diagnostic and communication tool for cases of impacted teeth in the mixed dentition that are candidates for orthodontic resolution. PMID:20836957

Nurko, Carlos

2010-01-01

220

Integrated flight/propulsion control system design based on a centralized approach  

NASA Technical Reports Server (NTRS)

An integrated flight/propulsion control system design is presented for the piloted longitudinal landing task with a modern, statically unstable, fighter aircraft. A centralized compensator based on the Linear Quadratic Gaussian/Loop Transfer Recovery methodology is first obtained to satisfy the feedback loop performance and robustness specificiations. This high-order centralized compensator is then partitioned into airframe and engine sub-controllers based on modal controllability/observability for the compensator modes. The order of the sub-controllers is then reduced using internally-balanced realization techniques and the sub-controllers are simplified by neglecting the insignificant feedbacks. These sub-controllers have the advantage that they can be implemented as separate controllers on the airframe and the engine while still retaining the important performance and stability characteristics of the full-order centralized compensator. Command prefilters are then designed for the closed-loop system with the simplified sub-controllers to obtain the desired system response to airframe and engine command inputs, and the overall system performance evaluation results are presented.

Garg, Sanjay; Mattern, Duane L.; Bullard, Randy E.

1989-01-01

221

Quantitative analysis of the central-chest lymph nodes based on 3D MDCT image data  

NASA Astrophysics Data System (ADS)

Lung cancer is the leading cause of cancer death in the United States. In lung-cancer staging, central-chest lymph nodes and associated nodal stations, as observed in three-dimensional (3D) multidetector CT (MDCT) scans, play a vital role. However, little work has been done in relation to lymph nodes, based on MDCT data, due to the complicated phenomena that give rise to them. Using our custom computer-based system for 3D MDCT-based pulmonary lymph-node analysis, we conduct a detailed study of lymph nodes as depicted in 3D MDCT scans. In this work, the Mountain lymph-node stations are automatically defined by the system. These defined stations, in conjunction with our system's image processing and visualization tools, facilitate lymph-node detection, classification, and segmentation. An expert pulmonologist, chest radiologist, and trained technician verified the accuracy of the automatically defined stations and indicated observable lymph nodes. Next, using semi-automatic tools in our system, we defined all indicated nodes. Finally, we performed a global quantitative analysis of the characteristics of the observed nodes and stations. This study drew upon a database of 32 human MDCT chest scans. 320 Mountain-based stations (10 per scan) and 852 pulmonary lymph nodes were defined overall from this database. Based on the numerical results, over 90% of the automatically defined stations were deemed accurate. This paper also presents a detailed summary of central-chest lymph-node characteristics for the first time.

Lu, Kongkuo; Bascom, Rebecca; Mahraj, Rickhesvar P. M.; Higgins, William E.

2009-02-01

222

Ultrastructural Localization of Calmodulin in Rat Incisor Ameloblasts and Odontoblasts During the Early Stages of Development  

Microsoft Academic Search

W visualized calmodulin distribution in rat incisor pre-secretory and secretory ameloblasts on ultrathin sections, using Lowicryl K4M embedding, antibody to calmodulin prepared from rabbit antiserum, and colloidal gold. The distribution of gold particles was compared with that observed in post-mitotic and secretory odontoblasts, and we also evaluated the effects of aldehyde fixation and fixation by rapid-freezing freeze-substitution.Evaluation of gold particles

M. Goldberg; F. Escaig; J. Feinberg; S. Weinman

1987-01-01

223

Cultured incisors display major modifications in basal lamina deposition without further effect on odontoblast differentiation  

Microsoft Academic Search

Matrix-mediated epithelio-mesenchymal interactions play a crucial role in the control of dental cytodifferentiations. Ultrastructural observation of the epithelio-mesenchymal junction in cultured embryonic mouse molars showed discrete zones with duplicated or multilayered basal laminae. The use of synthetic peptides demonstrated that the process was RGD*-independent, did not involve the YIGSR* sequence present on laminin and could occur spontaneously. Cultured incisors showed

Jean-Marie Meyer; Jean Victor Ruch; Marie Dominique Kubler; Christian Kupferle; Hervé Lesot

1995-01-01

224

Remineralization of Bovine Incisor Root Lesions in vitro: The Role of the Collagenous Matrix  

Microsoft Academic Search

This study deals with the role of collagen in the remineralization of bovine incisor root lesions. The degradability of the collagenous matrix after in vitro remineralization was also investigated. The root surfaces were exposed to 0.1 M acetic acid, pH 4.0, to produce erosive lesions or to 0.1 M lactic acid, 0.2 mM methane hydroxy diphosphonate, pH 5.0, to produce

B. Klont; J. M. ten Cate

1991-01-01

225

Endodontic treatment of immature maxillary lateral incisor with two canals: type 3 dens invaginatus.  

PubMed

Dens invaginatus is a developmental anomaly. The nonsurgical endodontic treatment of a type 3 dens invaginatus with a large periradicular lesion in a maxillary left lateral incisor of a 10-year-old girl is presented. In spite of difficult diagnosis and treatment of type 3 dens invaginatus, nonsurgical treatment was performed successfully. Resolution of the periradicular lesion and apical closure was observed after 1-year follow-up. PMID:20580274

Altunta?, Alev; C?nar, Ca?da?; Akal, Ne?e

2010-10-01

226

Management of geminated maxillary lateral incisor using cone beam computed tomography as a diagnostic tool  

PubMed Central

Geminated teeth are consequences of developmental anomalies leading to joined elements, due to incomplete attempt of one tooth germ to divide into two. This case report describes successful endodontic treatment of an unaesthetic geminated permanent maxillary lateral incisor tooth and its esthetic rehabilitation using all ceramic crowns. Newer imaging technique like cone beam computed tomography was taken for the better understanding of the complicated root canal morphology.

James, Elizabeth Prabha; Johns, Dexton Antony; Johnson, KI; Maroli, Ramesh Kumar

2014-01-01

227

Treatment outcome and efficacy of an aligner technique - regarding incisor torque, premolar derotation and molar distalization  

PubMed Central

Background The aim of this study was to investigate the efficacy of orthodontic treatment using the Invisalign® system. Particularly, we analyzed the influence of auxiliaries (Attachment/Power Ridge) as well as the staging (movement per aligner) on treatment efficacy. Methods We reviewed the tooth movements of 30 consecutive patients who required orthodontic treatment with Invisalign®. In all patients, one of the following tooth movements was performed: (1) Incisor Torque >10°, (2) Premolar derotation >10° (3) Molar distalization >1.5 mm. The groups (1)-(3) were subdivided: in the first subgroup (a) the movements were supported with the use of an attachment, while in the subgroup (b) no auxiliaries were used (except incisor torque, in which Power Ridges were used). All tooth movements were performed in a split-mouth design. To analyze the clinical efficacy, pre-treatment and final plaster cast models were laser-scanned and the achieved tooth movement was determined by way of a surface/surface matching algorithm. The results were compared with the amount of tooth movement predicted by ClinCheck®. Results The overall mean efficacy was 59% (SD?=?0.2). The mean accuracy for upper incisor torque was 42% (SD?=?0.2). Premolar derotation showed the lowest accuracy with approximately 40% (SD?=?0.3). Distalization of an upper molar was the most effective movement, with efficacy approximately 87% (SD?=?0.2). Conclusion Incisor torque, premolar derotation and molar distalization can be performed using Invisalign® aligners. The staging (movement/aligner) and the total amount of planned movement have an significant impact on treatment efficacy.

2014-01-01

228

The Multidisciplinary Management of Fused Maxillary Lateral Incisor with a Supernumerary Tooth in Cleft Lip Adolescence  

PubMed Central

Fusion, an uncommon anomaly of the hard dental tissues, is potentially the cause of clinical problems related to esthetics, tooth spacing, and other periodontal complications. This paper describes a multidisciplinary approach involving surgical, endodontic, restorative, and orthodontic attention for the successful, functional, and esthetic rehabilitation of a maxillary left lateral incisor fused with a supernumerary tooth in unilateral cleft lip adolescence in contralateral side. After clinical and radiographic examinations, a fusion between the left maxillary lateral incisor and a supernumerary tooth was diagnosed in the patient, and a small connection was detected between the pulp systems of the two root canals. The case reported in this paper presents the successful resolution of a fused maxillary lateral incisor with a supernumerary tooth, using endodontic, surgical, restorative, and orthodontic management. The decision made in extracting or retaining the fused tooth depends on the arch discrepancy and esthetic needs. Future studies, with long-term followup, will be helpful in evaluating the long-term efficacy of the different treatment options.

Yagci, Ahmet; Cantekin, Kenan; Buyuk, Suleyman Kutalmis; Pala, Kansad

2014-01-01

229

?11?1 Integrin-Dependent Regulation of Periodontal Ligament Function in the Erupting Mouse Incisor  

PubMed Central

The fibroblast integrin ?11?1 is a key receptor for fibrillar collagens. To study the potential function of ?11 in vivo, we generated a null allele of the ?11 gene. Integrin ?11?/? mice are viable and fertile but display dwarfism with increased mortality, most probably due to severely defective incisors. Mutant incisors are characterized by disorganized periodontal ligaments, whereas molar ligaments appear normal. The primary defect in the incisor ligament leads to halted tooth eruption. ?11?1-defective embryonic fibroblasts displayed severe defects in vitro, characterized by (i) greatly reduced cell adhesion and spreading on collagen I, (ii) reduced ability to retract collagen lattices, and (iii) reduced cell proliferation. Analysis of matrix metalloproteinase in vitro and in vivo revealed disturbed MMP13 and MMP14 synthesis in ?11?/? cells. We show that ?11?1 is the major receptor for collagen I on mouse embryonic fibroblasts and suggest that ?11?1 integrin is specifically required on periodontal ligament fibroblasts for cell migration and collagen reorganization to help generate the forces needed for axial tooth movement. Our data show a unique role for ?11?1 integrin during tooth eruption.

Popova, Svetlana N.; Barczyk, Malgorzata; Tiger, Carl-Fredrik; Beertsen, Wouter; Zigrino, Paola; Aszodi, Attila; Miosge, Nicolai; Forsberg, Erik; Gullberg, Donald

2007-01-01

230

Development of the oxytalan fiber system in the periodontal space of rat incisors.  

PubMed

The present study clarifies developmental organization of the oxytalan fiber system in the periodontal space of both the enamel (labial) and cementum (lingual) sides of rat incisors. The number of oxytalan fibers per unit area (?m(2)) was counted in rat incisors at stages of embryonic day 20 (E20) to postnatal day 35 (P35). Oxytalan fibers in the periodontal space of the enamel side were apt to decrease in number during the postnatal period, whereas their number remained almost unchanged on the cementum side during the developmental period. When the incisor emerged through the gum at P11, thinner oxytalan fibers distributed in the apical growing periodontium of the cementum side seemed to be fused with one another to become thicker fibers as has been reported for rat molars (Inoue et al., 2012). Thus, the oxytalan fiber system in the periodontal space represented significant differences in its distributional density between the enamel and cementum sides after E23. At the stage of P35, oxytalan fibers presented significantly denser distribution in all territories of the periodontal ligament of the cementum side versus the enamel side. The present findings claim that the oxytalan fiber system might bind the tooth to the periodontal ligament and provide equilibrium of vascular system and control of blood flow in the periodontal ligament of the cementum side, while it might exclusively regulate the high level of physiologically adapted vasculature in the periodontal space of the enamel side. PMID:23742981

Inoue, Kouji; Hara, Yaiko; Kuroda, Noriyuki; Sato, Tetsuji

2013-10-01

231

Long-term preservation of Bone Morphogenetic Activity in stored demineralized murine incisors.  

PubMed

Demineralized bone or dentine implanted intramuscularly induce endochondral bone formation. This phenomenon, termed "bone induction" is triggered by non-collagenous signal molecules, named "Bone Morphogenetic Proteins" (BMPs), released from bone or dentine. Demineralization of bone/dentine prior their implantation facilitates the release of BMPs from the extracellular matrix allowing to reach a BMP threshold level needed to initiate the process of differentiation of mesenchymal cells towards an osteogenic/chondrogenic lineage. Unprocessed, mineralized tissues usually fail to induce cartilage/bone. Isolated BMPs are commercially available, and in clinical practice are an alternative for demineralized tissues, however, in many cases demineralized bone has advantages over soluble BMPs, as it combines both bone inducing principles and mechanical properties, a feature important for bridging bone fracture and filling bone defects. Demineralized bones are an inexpensive source of bone forming agents for bone-fracture healing or filling bone defects. In this report we demonstrated that storage of lyophilized demineralized murine incisors for 30 months does not deteriorate its osteoinductive potency and colonizing induced bone by bone marrow. Lyophylized incisors, stored for 0-30 months at refrigator were implanted intramuscularly and recovered, together with surrounding tissues at various time intervals ranging 10-450 days. Bone closely associated with implant was observed in about 87% of cases, regardless the storage duration. It is concluded that storage of demineralized and lyophilized incisor matrices for at least 30 months does not change their osteoinductive potency. PMID:23563912

W?odarski, Krzysztof H; Szcz?sny, Grzegorz; Kuzaka, Boles?aw; W?odarski, Pawe? K

2013-01-01

232

The dentinal structure of equine incisors: a light and scanning electron-microscopic study.  

PubMed

This paper gives an anatomical overview of the dentinal structure in equine incisor teeth with special reference to the three-dimensional organization, the number and the diameter of the dentinal tubules. The spatial arrangement of equine dentine was examined by scanning electron microscopy of occlusal surfaces and longitudinally fractured teeth and by light microscopy of both decalcified and ground sections. The dentinal tubules of the peripherally situated primary dentine were directly continuous with those of the circumpulpal secondary dentine. The tubules had numerous side branches along their entire course and ramified into terminal branches near the dentino-enamel junction. Tubules of tertiary dentine, situated in the centre of the dental star, were few in number and not continuous with those of the surrounding secondary dentine. On non-etched incisors tubular orifices were clogged by an amorphous smear layer that covered the occlusal surface. On etched occlusal surfaces the numerical tubular density was calculated in different zones. The largest number of tubules per unit area was situated in the secondary dentine forming the dark periphery of the dental star, whereas the smallest number was present in the tertiary dentine located in the pale centre of the dental star. Dentinal tubular diameters were measured at various distances from the pulp. They were widest near the pulpal wall and narrowed progressively towards the dentino-enamel junction. Tubular widths measured on etched occlusal surfaces were considerably larger than those measured on undecalcified incisors due to the removal of intratubular dentine during the etching process. PMID:11014917

Muylle, S; Simoens, P; Lauwers, H

2000-01-01

233

[Extended subfrontal approach to the central cranial base - analysis of the surgical technique in cadaver simulation].  

PubMed

The aim of the study was to present consecutive stages of the extended subfrontal approach (ESA). Eight simulations of ESA were performed on non-fixed human cadavers without any known pathologies in the head and neck. The consecutive stages of the procedure were documented with photographs and schematic diagrams. The starting point for ESA is a bifrontal craniotomy and osteotomy including the base of the nose and superior parts of the orbits. If the anterior cranial base is not invaded by the tumour, an attempt to partially preserve olfaction is possible. Wound closure after removal of the tumour with ESA requires reconstruction of the tissue barrier between the cranial cavity, paranasal sinuses and nasopharynx. The extended subfrontal approach is a reproducible technique which provides surgical penetration of the central skull base. This approach is particularly useful in the surgical treatment of tumours expanding along the midline, superiorly and inferiorly to the skull base. PMID:19353445

Ladzi?ski, Piotr; Maliszewski, Mariusz

2009-01-01

234

Centralized, decentralized, and independent control of a flexible manipulator on a flexible base  

NASA Technical Reports Server (NTRS)

The dynamics and control of a flexible manipulator arm with payload mass on a flexible base in space are considered. The controllers are provided by one torquer at the center of the base and one torquer at the connection joint of the robot and the base. The nonlinear dynamics of the system is modeled by applying the finite element method and Lagrangian formula. Three control strategies are considered and compared, i.e., centralized control, decentralized control, and independent control. All these control designs are based on the linear quadratic regulator theory. A mathematical decomposition is used in the decentralization process so that the coupling between the subsystems is weak, while a physical decomposition is used in the independent control design process. For both the decentralized and the independent controls, the stability of the overall linear system is checked before a numerical simulations is initiated. Two numerical examples show that the response of the independent control system are close to those of the centralized control system, while the responses of the decentralized control system are not.

Li, Feiyue; Bainum, Peter M.; Xu, Jianke

1991-01-01

235

Central FPGA-based destination and load control in the LHCb MHz event readout  

NASA Astrophysics Data System (ADS)

The readout strategy of the LHCb experiment is based on complete event readout at 1 MHz. A set of 320 sub-detector readout boards transmit event fragments at total rate of 24.6 MHz at a bandwidth usage of up to 70 GB/s over a commercial switching network based on Gigabit Ethernet to a distributed event building and high-level trigger processing farm with 1470 individual multi-core computer nodes. In the original specifications, the readout was based on a pure push protocol. This paper describes the proposal, implementation, and experience of a non-conventional mixture of a push and a pull protocol, akin to credit-based flow control. An FPGA-based central master module, partly operating at the LHC bunch clock frequency of 40.08 MHz and partly at a double clock speed, is in charge of the entire trigger and readout control from the front-end electronics up to the high-level trigger farm. One FPGA is dedicated to controlling the event fragment packing in the readout boards, the assignment of the farm node destination for each event, and controls the farm load based on an asynchronous pull mechanism from each farm node. This dynamic readout scheme relies on generic event requests and the concept of node credit allowing load control and trigger rate regulation as a function of the global farm load. It also allows the vital task of fast central monitoring and automatic recovery in-flight of failing nodes while maintaining dead-time and event loss at a minimum. This paper demonstrates the strength and suitability of implementing this real-time task for a very large distributed system in an FPGA where no random delays are introduced, and where extreme reliability and accurate event accounting are fundamental requirements. It was in use during the entire commissioning phase of LHCb and has been in faultless operation during the first two years of physics luminosity data taking.

Jacobsson, R.

2012-10-01

236

Effect of Er,Cr:YSGG laser irradiation on eruption of rat mandibular incisor after disturbance of the enamel organ in the pulp  

Microsoft Academic Search

To investigate the efficacy of Er,Cr:YSGG (erbium,chromium:yttrium scandium gallium garnet) laser irradiation in root canal preparation and to evaluate its effect on eruption of rat incisors after disturbance of the enamel organ in the pulp, 20 canals of lower left incisor teeth were prepared by K-files followed by Er,Cr:YSGG laser irradiation, and 20 canals of right incisors were subjected to

Yoshiko Murakami Masuda; Mozammal Hossain; Xiaogu Wang; Emi Matsuoka; Tomohiro Okano; Koukichi Matsumoto

2006-01-01

237

Systematic review of changes in maxillary incisor exposure and upper lip position with Le Fort I type osteotomies with or without cinch sutures and/or VY closures.  

PubMed

The aim was to systematically review the maxillary incisor exposure and upper lip position changes with Le Fort I type osteotomies for advancement ± impaction with rigid internal fixation, taking into account the use of cinch sutures and VY closures. Electronic databases (Cochrane Library, Medline, Embase, and Web of Science) were searched using medical subject headings (MeSH), key words, truncations, and Boolean operators. Hand searching was also undertaken. Of 979 articles identified, 15 were included (11 retrospective, two prospective, and two unspecified). Relevant study details and outcomes were recorded on a spreadsheet, along with an assessment of their quality. In total, these studies assessed 419 patients (266 female, 118 male) with a mean age of 26.4 years (range 14-57 years). Soft tissue changes were assessed on lateral cephalometric radiographs. The mean maxillary hard tissue advancement and impaction ranged between 0.94 and 8.77 mm and -0.56 and 4.2 mm, respectively. The ranges of ratios demonstrated that from pronasale (0.24-0.35) to labrale superius (0.36-1.43), the soft tissues followed the underlying horizontal hard tissue movement increasingly more closely. Alar base cinch sutures and VY closures tended to increase these ratios. The soft tissue response was more variable vertically. None of the studies reported on maxillary incisor exposure change. More good quality prospective studies are needed. PMID:24103543

Khamashta-Ledezma, L; Naini, F B

2014-01-01

238

An Innovative Approach to Treat Incisors Hypomineralization (MIH): A Combined Use of Casein Phosphopeptide-Amorphous Calcium Phosphate and Hydrogen Peroxide--A Case Report  

PubMed Central

Molar Incisor Hypomineralization (MIH) is characterized by a developmentally derived deficiency in mineral enamel. Affected teeth present demarcated enamel opacities, ranging from white to brown; also hypoplasia can be associated. Patient frequently claims aesthetic discomfort if anterior teeth are involved. This problem leads patients to request a bleaching treatment to improve aestheticconditions.Nevertheless, hydrogen peroxide can produce serious side-effects, resulting from further mineral loss. Microabrasion and/or a composite restoration are the treatments of choice in teeth with mild/moderate MIH, but they also need enamel loss. Recently, a new remineralizing agent based on Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP) has been proposed to be effective in hypomineralized enamel, improving also aesthetic conditions. The present paper presents a case report of a young man with white opacities on incisors treated with a combined use of CPP-ACP mousse and hydrogen peroxide gel to correct the aesthetic defect. The patient was instructed to use CPP-ACP for two hours per day for three months in order to obtain enamel remineralization followed by a combined use of CPP-ACP and bleaching agent for further two months. At the end of this five-month treatment, a noticeable aesthetic improvement of the opacities was observed.

Mastroberardino, Stefano; Campus, Guglielmo; Strohmenger, Laura; Villa, Alessandro; Cagetti, Maria Grazia

2012-01-01

239

External apical root resorption in maxillary root-filled incisors after orthodontic treatment: A split-mouth design study  

PubMed Central

Introduction: The purpose of this study was to compare, in a split mouth design, the external apical root resorption (EARR) associated with orthodontic treatment in root-filled maxillary incisors and their contralateral teeth with vital pulps. Methodology: The study sample consisted of 38 patients (14 males and 24 females), who had one root-filled incisor before completion of multiband/bracket orthodontic therapy for at least 1 year. For each patient, digital panoramic radiographs taken before and after orthodontic treatment were used to determine the root resortion and the proportion of external root resorption (PRR), defined as the ratio between the root resorption in the endodontically treated incisor and that in its contralateral incisor with a vital pulp. The student’s t-test, chi-square test and logistic regression analysis were used to determine statistical significance. Results: There was no statistically significant difference (p > 0.05) between EARR in vital teeth (1.1 ± 1.0 mm) and endodontically treated incisors (1.1 ± 0.8 mm). Twenty-six patients (68.4%) showed greater resorption of the endodontically treated incisor than its homolog vital tooth (p > 0.05). The mean and standard deviation of PPR were 1.0 ± 0.2. Multivariate logistic regression suggested that PRR does not correlate with any of the variables analyzed. Conclusions: There was no significant difference in the amount or severity of external root resorption during orthodontic movement between root-filled incisors and their contralateral teeth with vital pulps. Key words:Endodontics, orthodontics, root canal treatment, root resorption.

Amarilla, Almudena; Espinar-Escalona, Eduardo; Castellanos-Cosano, Lizett; Martin-Gonzalez, Jenifer; Sanchez-Dominguez, Benito; Lopez-Frias, Francisco J.

2012-01-01

240

Central obesity in Yemeni children: A population based cross-sectional study  

PubMed Central

AIM: To establish percentile curves and to explore prevalence and correlates of central obesity among Yemeni children in a population based cross-sectional study. METHODS: A representative sample of 3114 Yemeni children (1564 boys, 1550 girls) aged 6-19 years participating in the HYpertension and Diabetes in Yemen study was studied. Data collection was conducted at home by survey teams composed of two investigators of both genders. Study questionnaire included questions about demographics, lifestyle, and medical history. Anthropometric measurements included body weight, height, waist circumference (WC) and hip circumferences. Waist to hip ratio (WHR) and waist-to-height ratio (WHtR) were then calculated. Age and gender specific smoothed percentiles of WC, WHR, and WHtR were obtained using lambda-mu-sigma parameters (LMS method). The independent predictors of central obesity defined as (1) WC percentile ? 90th; (2) WHtR ? 0.5; or (3) WC percentile ? 90th and WHtR ? 0.5, were identified at multivariate logistic regression analysis adjusted for age, gender, urban/rural location, years of school education, sedentary/active life-style. RESULTS: Percentile curves for WC, WHR and WHtR are presented. Average WC increased with age for both genders. Boys had a higher WC than girls until early adolescence and thereafter girls had higher values than boys. WHR decreased both in boys and girls until early adolescence. Thereafter while in boys it plateaued in girls it continued to decrease. Mean WHtR decreased until early adolescence with no gender related differences and thereafter increased more in girls than in boys towards adult age. Prevalence of central obesity largely varied according to the definition used which was 10.9% for WC ? 90th percentile, 18.3% for WHtR ? 0.5, and 8.6% when fulfilling both criteria. At adjusted logistic regression WC ? 90th percentiles and WHtR ? 0.5 were less prevalent in rural than in urban areas (OR = 0.52, 95%CI: 0.41-0.67 and 0.66, 0.54-0.79 respectively), being more prevalent in children with sedentary lifestyle rather than an active one (1.52, 95%CI: 1.17-1.98 and 1.42, 95%CI: 1.14-1.75, respectively). CONCLUSION: Yemeni children central obesity indices percentile curves are presented. Central obesity prevalence varied according to the definition used and was more prevalent in urban sedentary subjects.

Bamoshmoosh, Mohamed; Massetti, Luciano; Aklan, Hameed; Al-Karewany, Mahdi; Goshae, Husni Al; Modesti, Pietro Amedeo

2013-01-01

241

New approaches to solve old water problems: community based organizations in Central Asia  

NASA Astrophysics Data System (ADS)

The dry summer of 2009 has once again shown unsteadiness of economy of the Central-Asian countries, first of all, in agricultural sector and serious dependence of the region on water resources. For example, decreasing of water level in Toktogul reservoir forces the Government of the Kyrgyz Republic, the country where the largest rivers of the Central Asia originate, to the systematic switching-off of the electricity in three regions. Already in the spring of 2009, the experts predicted decreasing of gross production of agriculture in region, especially for the main cultures of cotton and rice. Coupled by natural cataclysms, the problems with water resources management have seriously aggravated conditions that are directly reflected on the livelihood of the rural population of Central Asia. This demands a search for new approaches and methods of solution of the main problems of water resources management. Despite the fact that the main issues of water distribution are solved at a level of the governments of the countries of Central Asia, a serious role in this process is associated directly to local water users. In recent years in some countries of the region, a process of creation of new community based Institutes of water resources management like Water Users Associations of (WUA) has started. The main idea for creation of these organizations is the necessity to involve the local water users like farmers to the process of water resources management and distribution. However, activity of the WUAs in the region has shown certain weaknesses both regarding the legal status of these organizations and institutional development. The main weakness of many WUAs is a lack of opportunities and mechanisms of involving of associations in decision-making processes. Members of WUAs have an opportunity to participate in distribution of water only within the borders of the associations while the main requirement of efficient water resources management is the principle of the integrated water management. The essence of this principle is that issues of water use and water distribution should be solved in coordination and in view of interests of all partners from other countries of the region. The next important issue is the necessity to strengthen the institutional capacity of WUAs. First of all, it is related to providing new approaches in training of members of associations in organizational management, fundraising, and modern technologies of natural resources management. It would be useful as well to strengthen cooperation between WUAs of neighboring countries in order to create information exchange and distribution of best practices between them. Hence, cooperation between the WUAs of the Central Asia countries could become an example for local governments for an integrated solution of problems of distribution and water resources management in the region.

Nurymgereyev, Kanysh

2010-05-01

242

Bedside prediction of airway length by measuring upper incisor manubrio-sternal joint length  

PubMed Central

Background: Malpositioning of endotracheal tube may lead to serious complications like endobronchial intubation or accidental extubation. Using anatomical measurements for prediction of airway length would be more practical in resource constrained settings. Materials and Methods: One hundred adult patients of American Society of Anesthesiologists (ASA) grade 1 or 2, without any evidence of difficult airway, were randomly allocated to two cohorts — a model cohort of 70 (50 males) and test cohort of 30 (20 males) subjects. Height, the straight length from the upper incisor to manubrio-sternal joint in fully extended head position (IncManustL), the length from upper incisor to the carina in neutral head position (IncCarinaL), and degree of neck extension were measured in all subjects. Relationship between the two lengths in the model cohort was explored by Pearson's coefficient (r). Predictions were made for subjects in the test cohort and actual and predicted values assessed for agreement using intra-class correlation coefficient (ICC). Results: Good agreement was found between IncManustL and IncCarinaL for both male (r = 0.69) and female (r = 0.54) subjects. Multiple regression analysis suggested height to be another significant predictor, unlike age, weight, and neck extension. The gender-specific regression equations were used to predict IncCarinaL for the test cohort. ICC for absolute agreement between the actual and predicted values was 0.723 (95% CI 0.495-0.858). Conclusions: It is possible to predict airway length in adult Indian subjects by making two simple anatomical measurements, namely stature and incisor manubrio-sternal joint length.

Mukherjee, Sudipta; Ray, Manjushree; Pal, Rita

2014-01-01

243

[Central neurobiological mechanism of liver depression and spleen deficiency syndrome based on chronic stress: a review].  

PubMed

Some researchers focus on research of the nature of syndromes. The methods of combining traditional Chinese medicine syndrome and diseases and the correspondence between formulas and syndromes may be used in research of the nature of syndromes. According to combined theories of zang-organ state and seven emotions in traditional Chinese medicine with stress theory in modern medicine, the authors applied the methods of chronic immobilization stress to induce liver depression and spleen deficiency syndrome in rats based on the thinking of relativity on formula and syndrome. The research showed that the central neurobiology mechanism of liver depression and spleen deficiency syndrome closely correlates to the hypothalamic-pituitary-adrenal axis, brain-gut axis, myriad central neurotrophic factors, neurotransmitters, neuropeptides and hormones and their receptors, involving in many encephalic regions such as the hypothalamus, hippocampus, cortex, amygdale, etc. The authors will combine their previous work with multi-disciplinary research, such as genomics, proteomics, metabolomics and bioinformatics in future studies, to reveal the scientific connotations of liver depression and spleen deficiency syndrome. PMID:22237267

Li, Xiao-hong; Li, Jing-jing; Liu, Yue-yun; Chen, Jia-xu

2012-01-01

244

Physics-based real time ground motion parameter maps: the Central Mexico example  

NASA Astrophysics Data System (ADS)

We present the use of near real time ground motion simulations in the generation of ground motion parameter maps for Central Mexico. Simple algorithm approaches to predict ground motion parameters of civil protection and risk engineering interest are based on the use of observed instrumental values, reported macroseismic intensities and their correlations, and ground motion prediction equations (GMPEs). A remarkable example of the use of this approach is the worldwide Shakemap generation program of the United States Geological Survey (USGS). Nevertheless, simple approaches rely strongly on the availability of instrumental and macroseismic intensity reports, as well as the accuracy of the GMPEs and the site effect amplification calculation. In regions where information is scarce, the GMPEs, a reference value in a mean sense, provide most of the ground motion information together with site effects amplification using a simple parametric approaches (e.g. the use of Vs30), and have proven to be elusive. Here we propose an approach that includes physics-based ground motion predictions (PBGMP) corrected by instrumental information using a Bayesian Kriging approach (Kitanidis, 1983) and apply it to the central region of Mexico. The method assumes: 1) the availability of a large database of low and high frequency Green's functions developed for the region of interest, using fully three-dimensional and representative one-dimension models, 2) enough real time data to obtain the centroid moment tensor and a slip rate function, and 3) a computational infrastructure that can be used to compute the source parameters and generate broadband synthetics in near real time, which will be combined with recorded instrumental data. By using a recently developed velocity model of Central Mexico and an efficient finite element octree-based implementation we generate a database of source-receiver Green's functions, valid to 0.5 Hz, that covers 160 km x 300 km x 700 km of Mexico, including a large portion of the Pacific Mexican subduction zone. A subset of the velocity and strong ground motion data available in real time is processed to obtain the source parameters to generate broadband ground motions in a dense grid ( 10 km x 10 km cells). These are interpolated later with instrumental values using a Bayesian Kriging method. Peak ground velocity and acceleration, as well as SA (T=0.1, 0.5, 1 and 2s) maps, are generated for a small set of medium to large magnitude Mexican earthquakes (Mw=5 to 7.4). We evaluate each map by comparing against stations not considered in the computation.

Ramirez Guzman, L.; Contreras Ruiz Esparza, M. G.; Quiroz Ramirez, A.; Carrillo Lucia, M. A.; Perez Yanez, C.

2013-12-01

245

Implant rehabilitation of canines in case of bilaterally missing maxillary lateral incisors.  

PubMed

This article reports the successful treatment of a patient with a malocclusion and missing maxillary lateral incisors with an unusual implant-prosthetic rehabilitation in place of the canines. A man, 25 years 5 months of age, was referred by his general dentist with the chief complaint of retained maxillary deciduous canines. He had a skeletal Class I and an Angle Class I malocclusion with an open-bite tendency and prolonged retention of both deciduous canines. The malocclusion was treated with extraction of the maxillary deciduous canines, a fixed edgewise appliance, and implant-prosthesis rehabilitation in place of the canines. A functional and an esthetic occlusion was achieved. PMID:23810052

Bizetto, Murilo Sérgio Principe; Tessarollo, Fábio Rafael; Jimenez, Emigdio Enrique Orellana; Guariza-Filho, Odilon; Camargo, Elisa Souza; Tanaka, Orlando Motohiro

2013-07-01

246

The distribution of intratubular dentine in equine incisors: a scanning electron microscopic study.  

PubMed

The distribution of intratubular (peritubular) dentine was studied by scanning electron microscopy in 12 equine incisor teeth. High levels of intratubular dentine were found in the peripheral regions of the dentine. In these areas, a marked asymmetry occurred, as intratubular dentine was predominantly deposited onto the side of the dentinal tubular walls nearest to the dentino-enamel junction. The quantity and asymmetry of intratubular dentine were reduced towards the centre of the tooth. The significance of these variations in the amount and distribution of intratubular dentine between the different dentinal regions is discussed. PMID:11191613

Muylle, S; Simoens, P; Lauwers, H

2001-01-01

247

Holocene climate variability in lake Sonkul sediments (Kyrgyzstan, Central Asia) based on vegetation changes  

NASA Astrophysics Data System (ADS)

Western Central Asia, as a remote intracontinental setting located far from oceanic influences, is a key place for high-resolution paleoclimatic studies because different climate systems interact at different timescales and control the regional climate variability. A multiproxy study (pollen grains, palynofacies, and magnetic susceptibility) was conducted on Holocene sediments from the alpine lake Sonkul (3010 m, 41°48'33N / 75°07'38E; Tien Shan, Kyrgyzstan). The combination of sediment core proxies allowed the reconstruction of palaeoenvironmental and palaeoclimatic changes through lake level variations and vegetation dynamics between 8400 and 2000 cal. BP. A high-resolution age model was built on Holocene sediments, constituting one of the most accurate chronologies available in the Central Tien Shan. A quantitative reconstruction of climatic parameters using the "modern analogue vegetation types" (MAV) method was carried out to establish variations in temperature and precipitation patterns during the Holocene as based on variations in fossil pollen assemblages. Between 8400 and 5900 cal. BP, the climate conditions are cold and wet associated with a very low lake level. The Siberian High Pressure (SHP) and the Pacific Summer Monsoon (PSM) are the main mechanisms controlling climatic conditions during the early to mid-Holocene. Between 5900 and 4300 cal. BP, warm and moist conditions characterized the "Mid Holocene Optimum" interval where the combined influence of the Westerlies and the PSM is recorded. Our results reveal that the "Mid Holocene Optimum" period in Lake Sonkul sediments appears to be of shorter duration than in other lakes from the Tibetan plateau. Finally, between 4300 and 2000 cal. BP, the climate becomes persistently arid and warm, as it is nowadays, with a predominant influence of the Westerlies in summer and the SHP in winter. Our results show, therefore, that the lake Sonkul represents an excellent sedimentary archive in Central Asia for high-resolution climatic studies. It allows deciphering, at a high time resolution, the interactions between different climatic systems on environmental dynamics in Central Asia during the Holocene.

Mathis, M.; Sorrel, P.; Klotz, S.; Oberhänsli, H.

2012-04-01

248

Spatial and seasonal variability of base flow in the Verde Valley, central Arizona, 2007 and 2011  

USGS Publications Warehouse

Synoptic base-flow surveys were conducted on streams in the Verde Valley, central Arizona, in June 2007 and February 2011 by the U.S. Geological Survey (USGS), in cooperation with the Verde River Basin Partnership, the Town of Clarkdale, and Yavapai County. These surveys, also known as seepage runs, measured streamflow under base-flow conditions at many locations over a short period of time. Surveys were conducted on a segment of the Verde River that flows through the Verde Valley, between USGS streamflow-gaging stations 09504000 and 09506000, a distance of 51 river miles. Data from the surveys were used to investigate the dominant controls on Verde River base flow, spatial variability in gaining and losing reaches, and the effects that human alterations have on base flow in the surface-water system. The most prominent human alterations in the Verde Valley are dozens of surface-water diversions from streams, including gravity-fed ditch diversions along the Verde River.Base flow that entered the Verde River from the tributary streams of Oak Creek, Beaver Creek, and West Clear Creek was found to be a major source of base flow in the Verde River. Groundwater discharge directly into the Verde River near these three confluences also was an important contributor of base flow to the Verde River, particularly near the confluence with Beaver Creek. An examination of individual reaches of the Verde River in the Verde Valley found three reaches (largely unaffected by ditch diversions) exhibiting a similar pattern: a small net groundwater discharge in February 2011 (12 cubic feet per second or less) and a small net streamflow loss in June 2007 (11 cubic feet per second or less). Two reaches heavily affected by ditch diversions were difficult to interpret because of the large number of confounding human factors. Possible lower and upper bounds of net groundwater flux were calculated for all reaches, including those heavily affected by ditches.

Garner, Bradley D.; Bills, Donald J.

2012-01-01

249

Access to the Central Skull Base Via a Modified Le Fort I Maxillotomy  

PubMed Central

We describe a modification of the standard Le Fort I maxillotomy in favor of a unilateral palatal hinge flap. Used in combination with a partial medical maxillectomy, submucous resection of the nasal septum, and contralateral inferior turbinectomy, this approach provides direct access to the entire nasal cavity, ipsilateral maxillary antrum, pterygopalatine fossa, nasopharynx, clivus, and first two cervical vertebrae. Use of the palatal hinge serves both to maintain palatal vascularity and eliminates the need for intermaxillary fixation. Facial incisions are avoided through a midfacial degloving approach. A variety of other surgical techniques used to access the central skull base are critically reviewed and compared with this new technique. ImagesFigure 6Figure 11Figure 15Figure 16

Catalano, Peter J.; Biller, Hugh F.; Sachdev, Ved

1993-01-01

250

Meteorological Factors-Based Spatio-Temporal Mapping and Predicting Malaria in Central China  

PubMed Central

Despite significant reductions in the overall burden of malaria in the 20th century, this disease still represents a significant public health problem in China, especially in central areas. Understanding the spatio-temporal distribution of malaria is essential in the planning and implementing of effective control measures. In this study, normalized meteorological factors were incorporated in spatio-temporal models. Seven models were established in WinBUGS software by using Bayesian hierarchical models and Markov Chain Monte Carlo methods. M1, M2, and M3 modeled separate meteorological factors, and M3, which modeled rainfall performed better than M1 and M2, which modeled average temperature and relative humidity, respectively. M7 was the best fitting models on the basis of based on deviance information criterion and predicting errors. The results showed that the way rainfall influencing malaria incidence was different from other factors, which could be interpreted as rainfall having a greater influence than other factors.

Huang, Fang; Zhou, Shuisen; Zhang, Shaosen; Zhang, Hongwei; Li, Weidong

2011-01-01

251

Study of the dimensions of the lateral incisors and their involvement in anterior tooth-size discrepancy.  

PubMed

Tooth-size discrepancy (TSD), i.e. the disproportion between the size of the maxillary teeth and that of the mandibular teeth, impacts the quality of esthetic and occlusal results in orthodontic treatment. Various studies have shown that, in anterior TSDs, the deficit is most often maxillary and the small size of the upper lateral incisor is incriminated. The present study was performed on a sample of 30 moulds from Moroccan patients displaying an anterior TSD. The differences in the sizes of the upper and lower lateral incisors were compared with a control sample with normal occlusion. The aim of the study was to check the validity of similarity of size between the upper and the lower lateral incisors as a clinical sign of possible anterior TSD. Our results confirmed the efficacy of this rapidly detectable clinical sign in the diagnosis of anterior TSDs. PMID:20303916

Regragui, Salwa; Azaroual, Faouzi; Tlemsani, Houda; Aalloula, El houssaine

2009-09-01

252

On adaptive HVAC based on a De-Centralized algorithm using K:1 transmission protocol for Autonomous Wireless Sensor Network  

Microsoft Academic Search

This paper presents the design of an adaptive HVAC based on psychrometric analysis and a De-Centralized control Algorithm for an Autonomous Wireless Sensor Network. The proposed system aims to initially differentiate the area under consideration into active and inactive zones and perform control operations on them. The De-Centralized control methodology follows a K:1 transmission protocol for optimized K-Coverage by allowing

Addwiteey Chrungoo; Akshay Kumar; Pradeep Kumar; Jai Parkash Godara

2010-01-01

253

Situational Lightning Climatologies for Central Florida: Phase IV: Central Florida Flow Regime Based Climatologies of Lightning Probabilities  

NASA Technical Reports Server (NTRS)

The threat of lightning is a daily concern during the warm season in Florida. Research has revealed distinct spatial and temporal distributions of lightning occurrence that are strongly influenced by large-scale atmospheric flow regimes. Previously, the Applied Meteorology Unit (AMU) calculated the gridded lightning climatologies based on seven flow regimes over Florida for 1-, 3- and 6-hr intervals in 5-, 10-, 20-, and 30-NM diameter range rings around the Shuttle Landing Facility (SLF) and eight other airfields in the National Weather Service in Melbourne (NWS MLB) county warning area (CWA). In this update to the work, the AMU recalculated the lightning climatologies for using individual lightning strike data to improve the accuracy of the climatologies. The AMU included all data regardless of flow regime as one of the stratifications, added monthly stratifications, added three years of data to the period of record and used modified flow regimes based work from the AMU's Objective Lightning Probability Forecast Tool, Phase II. The AMU made changes so the 5- and 10-NM radius range rings are consistent with the aviation forecast requirements at NWS MLB, while the 20- and 30-NM radius range rings at the SLF assist the Spaceflight Meteorology Group in making forecasts for weather Flight Rule violations during Shuttle landings. The AMU also updated the graphical user interface with the new data.

Bauman, William H., III

2009-01-01

254

Use of Forsus fatigue-resistant device in a patient with Class I malocclusion and mandibular incisor agenesis.  

PubMed

Orthodontic treatment in patients with congenitally missing teeth can be challenging. In this case report, we describe the treatment of a 15-year-old girl with mild dental crowding and 2 congenitally missing mandibular incisors. The Forsus fatigue-resistant device was used to move the mandible and the mandibular teeth forward. A new balanced and stable occlusion was achieved after treatment. When the treatment plan includes moving the mandibular teeth forward in a patient with mandibular incisor agenesis, the profile and the skeletal and dental features should be carefully scrutinized to ensure that balanced and esthetic results are achieved. PMID:24880853

Zhang, Ruofang; Bai, Yuxing; Li, Song

2014-06-01

255

Ring1a/b polycomb proteins regulate the mesenchymal stem cell niche in continuously growing incisors.  

PubMed

Rodent incisors are capable of growing continuously and the renewal of dental epithelium giving rise to enamel-forming ameloblasts and dental mesenchyme giving rise to dentin-forming odontoblasts and pulp cells is achieved by stem cells residing at their proximal ends. Although the dental epithelial stem cell niche (cervical loop) is well characterized, little is known about the dental mesenchymal stem cell niche. Ring1a/b are the core Polycomb repressive complex1 (PRC1) components that have recently also been found in a protein complex with BcoR (Bcl-6 interacting corepressor) and Fbxl10. During mouse incisor development, we found that genes encoding members of the PRC1 complex are strongly expressed in the incisor apical mesenchyme in an area that contains the cells with the highest proliferation rate in the tooth pulp, consistent with a location for transit amplifying cells. Analysis of Ring1a(-/-);Ring1b(cko/cko) mice showed that loss of Ring1a/b postnatally results in defective cervical loops and disturbances of enamel and dentin formation in continuously growing incisors. To further characterize the defect found in Ring1a(-/-);Ring1b(cko/cko) mice, we demonstrated that cell proliferation is dramatically reduced in the apical mesenchyme and cervical loop epithelium of Ring1a(-/-);Ring1b(cko/cko) incisors in comparison to Ring1a(-/-);Ring1b(fl/fl)cre- incisors. Fgf signaling and downstream targets that have been previously shown to be important in the maintenance of the dental epithelial stem cell compartment in the cervical loop are downregulated in Ring1a(-/-);Ring1b(cko/cko) incisors. In addition, expression of other genes of the PRC1 complex is also altered. We also identified an essential postnatal requirement for Ring1 proteins in molar root formation. These results show that the PRC1 complex regulates the transit amplifying cell compartment of the dental mesenchymal stem cell niche and cell differentiation in developing mouse incisors and is required for molar root formation. PMID:22562112

Lapthanasupkul, Puangwan; Feng, Jifan; Mantesso, Andrea; Takada-Horisawa, Yuki; Vidal, Miguel; Koseki, Haruhiko; Wang, Longlong; An, Zhengwen; Miletich, Isabelle; Sharpe, Paul T

2012-07-15

256

The congenitally missing upper lateral incisor. A retrospective study of orthodontic space closure versus restorative treatment.  

PubMed

Orthodontic treatment for patients with uni- or bilateral congenitally missing lateral incisors is a challenge to effective treatment planning. The two major alternatives, orthodontic space closure or space opening for prosthetic replacements, can both compromise aesthetics, periodontal health, and function. The aim of this retrospective study was to examine treated patients who had congenitally missing lateral incisors and to compare their opinion of the aesthetic result with the dentists' opinions of occlusal function and periodontal health. In this sample, 50 patients were identified. Thirty had been treated with orthodontic space closure, and 20 by space opening and a prosthesis (porcelain bonded to gold and resin bonded bridges). The patient's opinion of the aesthetic result was evaluated using the Eastman Esthetic Index questionnaire and during a structured interview. The functional status, dental contact patterns, periodontal condition, and quality of the prosthetic replacement was evaluated. In general, subjects treated with orthodontic space closure were more satisfied with the appearance of their teeth than those who had a prosthesis. No significant differences in the prevalence of signs and symptoms of temporomandibular dysfunction (TMD) were found. However, patients with prosthetic replacements had impaired periodontal health with accumulation of plaque and gingivitis. The conclusion of this study is that orthodontic space closure produces results that are well accepted by patients, does not impair temporomandibular joint (TMJ) function, and encourages periodontal health in comparison with prosthetic replacements. PMID:11212605

Robertsson, S; Mohlin, B

2000-12-01

257

Formation of the dentino-enamel interface in enamelysin (MMP-20)-deficient mouse incisors.  

PubMed

An anomalous dentino-enamel junction (DEJ), manifested by delamination of the enamel layer, was reported in enamelysin [matrix metalloproteinase-20 (MMP-20)] knockout (KO) mice. To better understand the possible role of MMP-20 in the formation of the DEJ, we performed transmission electron microscopy (TEM) studies of the DEJ at early stages of tooth morphogenesis in KO mice. Our TEM analysis revealed that in the incisors from KO mice the mantle dentin is hypomineralized at the onset of enamel mineralization. At this early stage, TEM revealed no apparent differences in nascent aprismatic enamel between the KO mice and the controls. Hypomineralized mantle dentin was also observed in the incisors from KO mice, as assessed by back-scattered SEM at the secretory and early maturation stages, but not in the late-maturation stage, suggesting that the mineralization of mantle dentin is not completely arrested, but rather postponed. Histological studies indicate that the organic content in the initial enamel layer remains very high throughout amelogenesis. These results imply that MMP-20 is involved in the regulation of mineralization in mantle dentin and demonstrate the complex nature of DEJ formation. They also suggest that the structural and functional properties of the DEJ are determined during the initial mineralization stages. PMID:16674658

Beniash, Elia; Skobe, Ziedonis; Bartlett, John D

2006-05-01

258

[Effects of lower canine distalization with sectional arches on the positions of lower incisors and molars].  

PubMed

The purpose of the study was to investigate the effects of lower canine distalization with .016 x 0.016 inch sectional arches on the positions of lower incisors and first permanent molars. Study was carried out on two lateral cephalograms taken at the beginning of treatment and at the end of canine distalization over a period of six months, from each of 17 subjects having a chronological age range of 11 years 8 months and 19 years and whose treatments with first premolar extraction were begun with .018 inch slot std. edgewise technique. Due to the mean lower canine distalization of 3 mm. till spacing of lower anteriors, mean lower incisor retrusion of 0.9 mm. concurrent with a mean decrease of 0.9 mm. in Holdaway difference were occurred which were both found to be statistically significant. Mesial movement of lower first permanent molars having a mean of 0.3 mm was not found to be significant. PMID:2101661

I?can, H N

1990-04-01

259

Investigation of the maxillary lateral incisor agenesis and associated dental anomalies in an orthodontic patient population  

PubMed Central

Objectives: The aim of this study was to investigate the prevalence of maxillary lateral incisor (MLI) agenesis and associated dental anomalies as well as skeletal patterns in an orthodontic population, and then to compare it with the prevalence of these anomalies in the general population. Study Design: The material of the present study included the records of the 3872 orthodontic patients. The followings were recorded for each subject with the agenesis of MLI: Age, sex, unilateral or bilateral absence, anterior-posterior skeletal relationship of the maxilla and mandible, and presence of associated dental anomalies. The occurrence of these anomalies was compared with data previously reported for the general populations. Results: Of the 3872 patients examined, 94 were found to have agenesis of the MLI, representing a prevalence of 2.4 per cent, with females being more frequently observed. The most commonly found associated anomalies were ectopic eruption of maxillary canines and reduced or peg- shaped contralateral incisor with the frequencies of 21.3 per cent and 20.2 per cent respectively. Conclusions: Patients with agenesis of MLI showed a significantly higher prevalence of skeletal Class III malocclusion compared with the general population. The prevalence of ectopic eruption, transposition, and transmigration of the maxillary canine and reduced or peg- shaped MLIs were significantly increased. Key words:Hypodontia, missing laterals, associated dental anomalies.

Kamak, Hasan; Yildirim, Hanifi; Ceylan, Ismail

2012-01-01

260

Comparison of Late Pleistocene and Modern Glacier Extents in Central Nepal Based on Digital Elevation Data and Satellite Imagery  

Microsoft Academic Search

Late Pleistocene and modern ice extents in central Nepal are compared to estimate equilibrium line altitude (ELA) depressions. New techniques are used for determining the former extent of glaciers based on quantitative, objective geomorphic analyses of a ?90-m resolution digital elevation model (DEM). For every link of the drainage network, valley form is classified as glacial or fluvial based on

Christopher C. Duncan; Andrew J. Klein; Jeffrey G. Masek; Bryan L. Isacks

1998-01-01

261

Familial malignant mesothelioma: a population-based study in central Italy (1980-2012).  

PubMed

Malignant mesothelioma is a sporadic cancer linked to asbestos exposure. Its occurrence among blood relatives (familial mesothelioma) may point to genetic susceptibility or shared exposures. The burden of the familial disease is unknown. The aims of the study were to assess at population level the proportion of familial mesotheliomas among all mesotheliomas and to investigate the family history of cancer among relatives of mesothelioma cases. We actively searched familial clusters based on a mesothelioma registry from central Italy (5.5 million people, 10% of the Italian population) of the National Mesothelioma Register network (ReNaM) as well as a pathology-based archive. Among 997 incident mesotheliomas recorded in a 32-year-period (1980-2012), we detected 13 clusters and 34 familial cases, accounting for 3.4% of all mesotheliomas. The most common clusters where those with affected siblings and unaffected parents. Asbestos exposure was occupational (n=7 clusters), household (n=2), environmental (n=1), or not attributable for insufficient information (n=3). There were 25 additional cancers in nine families. Some were cancer sites for which there is sufficient evidence (lung and larynx) or limited evidence (stomach and colon) of causal association with asbestos. The results suggest potential genetic recessive effects in mesothelioma that interact with asbestos exposure, but it is not possible to estimate the specific proportion attributable to each of these components. PMID:24684899

Ascoli, Valeria; Romeo, Elisa; Carnovale Scalzo, Caterina; Cozzi, Ilaria; Ancona, Laura; Cavariani, Fulvio; Balestri, Anna; Gasperini, Letizia; Forastiere, Francesco

2014-06-01

262

The PCR-Based Diagnosis of Central Nervous System Tuberculosis: Up to Date  

PubMed Central

Central nervous system (CNS) tuberculosis, particularly tuberculous meningitis (TBM), is the severest form of Mycobacterium tuberculosis (M.Tb) infection, causing death or severe neurological defects in more than half of those affected, in spite of recent advancements in available anti-tuberculosis treatment. The definitive diagnosis of CNS tuberculosis depends upon the detection of M.Tb bacilli in the cerebrospinal fluid (CSF). At present, the diagnosis of CNS tuberculosis remains a complex issue because the most widely used conventional “gold standard” based on bacteriological detection methods, such as direct smear and culture identification, cannot rapidly detect M.Tb in CSF specimens with sufficient sensitivity in the acute phase of TBM. Recently, instead of the conventional “gold standard”, the various molecular-based methods including nucleic acid amplification (NAA) assay technique, particularly polymerase chain reaction (PCR) assay, has emerged as a promising new method for the diagnosis of CNS tuberculosis because of its rapidity, sensitivity and specificity. In addition, the innovation of nested PCR assay technique is worthy of note given its contribution to improve the diagnosis of CNS tuberculosis. In this review, an overview of recent progress of the NAA methods, mainly highlighting the PCR assay technique, was presented.

Takahashi, Teruyuki; Tamura, Masato; Takasu, Toshiaki

2012-01-01

263

Slow Vertical Downwasting of Cold-Based Ice Sheets in the Rondane Area, Central Scandinavia  

NASA Astrophysics Data System (ADS)

The rate of ice-sheet downwasting following the Late Weichselian glacial maximum (LGM) c. 20 ka is crucial for estimating the vertical extent prior to and during the last deglaciation in central Scandinavia. The Scandinavian Ice Sheet was cold-based in this region, and air temperature is suggested to be the critical factor influencing the rate of downwasting until the final deglaciation took place close to 10 ka. Depending on when the deglaciation started, the rate of downwasting necessary to explain recent 'maximum' and 'minimum' estimates for ice-sheet thickness may differ by 1-2 orders of magnitude. Here we present figures for the rate of downwasting based on OSL-dated waterlain sediments exposed to daylight prior to deposition and 10Be exposure dates on erratic boulders and lateral meltwater channels cut into bedrock in different altitudes. The results indicate a very slow vertical downwasting until c. 15 ka, and a somewhat increase prior to c. 13 ka. After a stillstand related to the Younger Dryas (12.8-11.5 ka) the downwasting accelerated until all ice was gone close to 10 ka. The ice-sheet surface was locally lowered c. 120 m from the LGM to 13.8 ka, or about 2.4 cm/year on an average. The results imply that a much thinner continental ice sheet that hitherto suggested by ice-sheet modelling is necessary to explain field observations related to the last deglaciation in the Rondane area.

Dahl, S.; Linge, H.; Fabel, D.; Murray, A.

2007-12-01

264

Characteristics and Composition of Atmospheric Aerosols in Phimai, Central Thailand During BASE-ASIA  

NASA Technical Reports Server (NTRS)

Popular summary: Atmospheric aerosols play an important role in the Earth's climate system, and can also have adverse effects on air quality and human health. The environmental impacts of aerosols, on the other hand, are highly regional, since their temporal/spatial distribution is inhomogeneous and highly depends on the regional emission sources. To better understand the effects of aerosols, intensive field experiments are necessary to characterize the chemical and physical properties on a region-by-region basis. From late February to early May in 2006, NASA/GSFC's SMARTLabs facility was deployed at a rural site in central Thailand, Southeast Asia, to conduct a field experiment dubbed BASE-ASIA (Biomass-burning Aerosols in South East-Asia: Smoke Impact Assessment). The group was joined by scientists from the University of Hawaii and other regional institutes. Comprehensive measurements were made during the experiment, including aerosol chemical composition, optical and microphysical properties, as well as surface energetics and local . meteorology. This study analyzes part of the data from the BASE-ASIA experiment. It was found that, even for the relatively remote rural site, the aerosol loading was still substantial. Besides agricultural burning in the area, industrial pollution near the Bangkok metropolitan area, about 200 km southeast of the site, and even long-range transport from China, also contribute to the area's aerosol loading. The results indicate that aerosol pollution has developed into a regional problem for northern Indochina, and may become more severe as the region's population and economy continue to grow. Abstract: Comprehensive measurements of atmospheric aerosols were made in Phimai, central Thailand (15.l83 N, 102.565 E, elevation: 206 m) during the BASE-ASIA field experiment from late February to early May in 2006. The observed aerosol loading was sizable for this rural site (mean aerosol scattering: 108 +/- 64 Mm(exp -1); absorption: 15 +/- 8 Mm(exp -1); PM(sub 10) concentration: 33 +/- 17 miro-g/ cubic m and dominated by submicron particles. Major aerosol compounds included carbonaceous (OC: 9.5 +/- 3.6miro-g/ cubic m; EC: 2.0 2.3 miro-g/ cubic m and secondary species (SO4(2-): 6.4 +/- 3.7 miro-g/ cubic m, NH4(+): 2.2 +/- 1.3 miro-g/ cubic m). While the site was seldom under the direct influence of large forest fires to its north, agricultural fires were ubiquitous during the experiment, as suggested by the substantial concentration of K+ (0.56 +/- 0.33 micro-g/ cubic m). Besides biomass burning, aerosols in Phimai during the experiment were also strongly influenced by industrial and vehicular emissions from the Bangkok metropolitan region and long-range transport from southern China. High humidity played an important role in determining the aerosol composition and properties in the region. Sulfate was primarily formed via aqueous phase reactions, and hygroscopic growth could enhance the aerosol light scattering by up to 60%, at the typical morning RH level of 85%. The aerosol single scattering albedo demonstrated distinct diurnal variation, ranging from 0.86 +/- 0.04 in the evening to 0.92 +/- 0.02 in the morning. This experiment marks the first time such comprehensive characterization of aerosols was made for rural central Thailand. Our results indicate that aerosol pollution has developed into a regional problem for northern Indochina, and may become more severe as the region's population and economy continue to grow.

Li, Can; Tsay, Si-Chee; Hsu, N. Christina; Kim, Jin Young; Howell, Steven G.; Huebert, Barry J.; Ji, Qiang; Jeong, Myeong-Jae; Wang, Sheng-Hsiang; Hansell, Richard A.; Bell, Shaun W.

2012-01-01

265

Comparison of Central Dimmer Systems Based on Multiple-Tapped Autotransformer and High-Frequency Switching Converter  

Microsoft Academic Search

This paper compares two central dimmer system technologies used in street lighting. These dimmers are utilized in adaptive lighting systems based on high-intensity-discharge lamps and magnetic ballasts. The first technology is based on a multiple-tapped autotransformer which is commonly used for these types of installations. The second technology is based on a high-frequency switch converter (more specifically in a single-

Guillermo Velasco-Quesada; Manuel Roman-Lumbreras; Alfonso Conesa-Roca

2012-01-01

266

Covariance matrix adaptation evolution strategy based design of centralized PID controller  

Microsoft Academic Search

In this paper, design of centralized PID controller using Covariance Matrix Adaptation Evolution Strategy (CMAES) is presented. Binary distillation column plant described by Wood and Berry (WB) having two inputs and two outputs and by Ogunnike and Ray (OR) having three inputs and three outputs are considered for the design of multivariable PID controller. Optimal centralized PID controller is designed

M. Willjuice Iruthayarajan; S. Baskar

2010-01-01

267

Stromelysin-1 (MMP-3) in Forming Enamel and Predentine in Rat Incisor – Coordinated Distribution with Proteoglycans Suggests a Functional Role  

Microsoft Academic Search

Stromelysin-1 (matrix metalloproteinase-3) or proteoglycanase was visualized by light and electron microscopy immunolabelling in the forming zone of rat incisors. In predentine, labelling was more dense at the transition zone between the inner proximal third and the two outer thirds. Odontoblast processes were also positively stained, mostly in predentine and to a lesser degree in dentine. The dentine–enamel junction was

Rachel Hall; Dominique Septier; Graham Embery; Michel Goldberg

1999-01-01

268

EMG, force and discharge rate analysis of human jaw reflexes in response to axial stimulation of the incisor  

Microsoft Academic Search

Reflex studies utilising controlled stimulation along the long axis of human incisors are relatively new, and the effects that various stimulus parameters have on the elicited reflexes are not fully understood. Twelve subjects were recruited to determine the effects that contraction level, stimulus force and amount of constant force applied between stimuli have on the reflex response of the masseter

Russell S. A. Brinkworth; Kemal S. Türker

2005-01-01

269

Long-term development in the mandible and incisor crowding with and without an orthodontic stabilising appliance  

Microsoft Academic Search

Summary In children with dentoalveolar Class Il malocclusion with proclined upper incisors treated with extraction of the maxillary first premolars and appliance in the upper jaw only has been reported to increase the lower arch crowding when compared with children with untreated normal occlusion. Stabilising orthodontic appliances might therefore be useful in the lower jaw. A comparison was made of

Ulrike Schütz-Fransson; Krister Bjerklin; Jüri Kurol

1998-01-01

270

Long-term effects of Herbst treatment on the mandibular incisor segment: A cephalometric and biometric investigation  

Microsoft Academic Search

The purpose of this study was to analyze mandibular incisor changes during and after Herbst treatment with respect to tooth inclination and anterior crowding. The sample consisted of 24 Class II, Division 1 subjects (15 boys and 9 girls) treated with the Herbst appliance. Dental casts and lateral head films from before and after treatment, 6 months after treatment and

Ken Hansen; Theodoros G. Koutsonas; Hans Pancherz

1997-01-01

271

The contribution of a central pattern generator in a reflex-based neuromuscular model  

PubMed Central

Although the concept of central pattern generators (CPGs) controlling locomotion in vertebrates is widely accepted, the presence of specialized CPGs in human locomotion is still a matter of debate. An interesting numerical model developed in the 90s’ demonstrated the important role CPGs could play in human locomotion, both in terms of stability against perturbations, and in terms of speed control. Recently, a reflex-based neuro-musculo-skeletal model has been proposed, showing a level of stability to perturbations similar to the previous model, without any CPG components. Although exhibiting striking similarities with human gaits, the lack of CPG makes the control of speed/step length in the model difficult. In this paper, we hypothesize that a CPG component will offer a meaningful way of controlling the locomotion speed. After introducing the CPG component in the reflex model, and taking advantage of the resulting properties, a simple model for gait modulation is presented. The results highlight the advantages of a CPG as feedforward component in terms of gait modulation.

Dzeladini, Florin; van den Kieboom, Jesse; Ijspeert, Auke

2014-01-01

272

DEM-based determination of knickpoints in South Central Alborz Drainage Basin, N Iran  

NASA Astrophysics Data System (ADS)

Stream gradients of Karaj River and its tributaries in south central Alborz were examined using GIS and 30-m digital elevation models to discuss the distribution of knickpoints. In order to discriminate values at the index related to rock resistance, different levels of average rock strength were defined (by rock type and field observation) from very low strength (alluvial deposits), low strength (slope deposits), moderate strength (siltstone, shale), high strength (sandstone, conglomerate, limestone, and tuff), and very high strength (quartzite, and monzodiorit-monzogabbro). The observed SL index anomalies were then plotted on the map of the relative strength of materials and their relation to rock strength were analyzed utilizing GIS applications. Based upon the quantitative SL indices linked to relative rock resistance described above with field observations suggest that there are three knickzones. The identified knickzones occur widely in the study area and indicate that the knickzone is one of the common landforms in Karaj drainage basin. Although there is most resistance rock around the Amir-Kabir dam the knickpoints are more abundant there.

Khavari, R.

2010-05-01

273

A tunable protein-based scaffold for the study of central nervous system regeneration  

NASA Astrophysics Data System (ADS)

Central nervous system (CNS) injuries pose a significant and potentially debilitating health problem in society today and, to date, no successful clinical repair strategies have been advanced. The development of effective treatments is severely hindered by the quick formation of a complex, inhibitory scar at the site of CNS injury. This scar both physically blocks and chemically suppresses nerve regeneration. It has been hypothesized that combinatorial approaches involving biomaterial scaffolds, cell transplantation, and pro-survival factors, which provide a more permissive growth environment, have the highest chance of stimulating regeneration. The work completed in this thesis focuses on the design and characterization of a biomimetic hydrogel scaffold constructed from chemically crosslinked recombinant proteins. This protein-based scaffold has been designed to offer a flexible platform for the systematic optimization of key scaffold design parameters, such as mechanical strength, degradation, cellular interaction, molecule delivery, and topography. Specifically, a collection of proteins containing sequences previously shown to enhance cell adhesion, to promote neurite extension, and to exhibit varying susceptibility to cleavage by neurite-secreted proteases were synthesized to serve as the polymer backbone for the scaffold. Experiments were conducted to analyze the capacity of scaffolds, constructed from single proteins or mixtures of proteins, to independently control cell behavior, scaffold degradation properties, and scaffold mechanical properties based upon differences in the primary protein sequence and crosslinking conditions. In addition, composite scaffolds constructed by layered spatial deposition of chemically crosslinked, protease-degradable proteins were applied to the formation of dynamic internal, three-dimensional scaffold patterns that can be directly coupled to molecule delivery. Overall, this work demonstrates the tunable and bio-functional nature of these hydrogels and sets the framework for future studies into the development of effective protein-engineered scaffolds for CNS regeneration.

Straley, Karin

274

Cardiovascular safety of central nervous system stimulants in children and adolescents: population based cohort study  

PubMed Central

Objectives To evaluate the cardiac safety of central nervous system stimulants in children and adolescents. Design Population based retrospective cohort study. Setting Automated healthcare claims data from 1?219?847 children and young people eligible for 28 state Medicaid programmes from 1999 to 2006 linked to the Social Security Death Master File and the National Death Index. Participants Children and young people age 3-18 entered the cohort at the first diagnosis of a mental health condition commonly treated with stimulants (such as attention-deficit/hyperactivity disorder) after a minimum period of six months’ eligibility and were followed until loss of eligibility, their 19th birthday, admission to hospital for longer than 30 days, or death. Exclusion criteria included transplant recipients, receipt of dialysis, or claims indicating substance misuse. We retained high risk groups with similar use of stimulants as low risk children (such as children with congenital heart disease). Sociodemographic characteristics, cardiac risk factors, and psychiatric diagnoses obtained from before the index period were summarised with a propensity score. We used discrete survival analysis to estimate the relative risk for periods of stimulant use and non-use, adjusted for propensity score and antipsychotic use for the full cohort and the high risk and low risk groups. Main outcome measures Composite endpoint of stroke, acute myocardial infarction, or sudden cardiac death; a secondary composite endpoint added ventricular arrhythmia Results A total of 66 (95 including ventricular arrhythmia) events occurred during 2?321?311 years of follow-up. The odds ratio adjusted for propensity score and antipsychotic use for current versus no stimulant use was 0.62 (95% confidence interval 0.27 to 1.44), with a corresponding adjusted incidence rate of 2.2 and 3.5 per 100?000 patient years for current stimulant and non-use, respectively. Twenty six events occurred in high risk patients (incidence rate 63 per 100?000 patient years) with an odds ratio of 1.02 (0.28 to 3.69). Odds ratios for the secondary endpoint were similar to those for the primary endpoint (0.74, 0.38 to 1.46). Conclusions Treatment of children with central nervous stimulants is not significantly associated with an increase in the short term risk of severe cardiac events. Analyses cannot be generalised to children with long term use of stimulants. Furthermore, long term effects of slight increases in heart rate or blood pressure are unknown.

2012-01-01

275

Carbon Turnover in Organic Soils of Central Saskatchewan: Insights From a Core-Based Decomposition Study  

NASA Astrophysics Data System (ADS)

Field-based decomposition studies that examine several site types tend to use one of two approaches: Either the decay of one (or more) standard litters is examined in all sites, or litters native to each site type are incubated in the environment they came from. The first of these approaches examines effects of environment on decay, whereas the latter determines rates of mass loss characteristic of each site type. Both methods are usually restricted to a limited number of litters, and neither allows for a direct estimate of ecosystem-level parameters (e.g. heterotrophic respiration). In order to examine changes in total organic matter turnover along forest - peatland gradients in central Saskatchewan, we measured mass loss of native peat samples from six different depths (surface to 50 cm) over one year. Samples were obtained by sectioning short peat cores, and cores and samples were returned to their original position after determining the initial weight of each sample. A standard litter (birch popsicle sticks) was included at each depth, and water tables and soil temperature were monitored over the growing season. After one year, average mass loss in surface peat samples was similar to published values from litter bag studies, ranging from 12 to 21 percent in the environments examined. Native peat mass loss showed few systematic differences between sites or along the forest - peatland gradient, with over 60 percent of the total variability explained by depth alone. Mass loss of standard litter samples was highly variable, with high values in areas at the transition between upland and peatland that may have experienced recent disturbance. In combination, these results suggest strong litter-based control over natural rates of organic matter turnover. Estimates of heterotrophic respiration calculated from the mass loss data are higher than values obtained by eddy covariance or static chamber techniques, probably reflecting loss of material during the handling of samples or increased mass loss from manipulated profiles. Nevertheless, the core-based method is a useful tool in examining carbon dynamics of organic soils, since it provides a good relative index of organic matter turnover, and allows for separate examination of environmental and litter-based effects.

Bauer, I. E.; Bhatti, J. S.; Hurdle, P. A.

2004-05-01

276

Basement structure based on gravity anomaly in the northern Noto peninsula, Central Japan  

NASA Astrophysics Data System (ADS)

Upper crustal block structures are usually defined by using surface information, such as geological and morphological data. The northern Noto Peninsula, central Japan, is divided into four geological block structures from tectonic geomorphologic perspectives (Ota and Hirakawa, 1979). This division is based on the surface crustal movement. To image the geological blocks three-dimensionally, it is necessary to construct a subsurface structure model. Gravity survey can clarify the detailed subsurface structure with dense gravity measurement. From the detailed Bouguer anomalies in the northwestern Noto Peninsula, Honda et al. (2008) suggested that the rupture size of the 2007 Noto Hanto earthquake was constrained by the geological block structures. Hiramatsu et al. (2008) also suggested the active faults on the seafloor, such as the source fault of the 2007 Noto Hanto earthquake plays a major role for the formation of the geological block structures. In this study, we analyze subsurface density structure based on the Bouguer anomaly and estimate the distribution of basement depth in the northern Noto Peninsula. We focus the relationship among the basement depth, the block structures and the active faults on the seafloor and discuss the block movement in the northern Noto Peninsula. We compiled the data measured and published previously (Gravity Database of Southwest Japan, 2001; Geological survey of Japan, 2004; Geographical survey institute of Japan, 2006; The Gravity Research Group in Southwest Japan, 2001; Komazawa and Okuma, 2010; Hokuriku electric power Co. Ltd., undisclosed) and calculated Bouguer anomaly in the northern Noto Peninsula. Based on this Bouguer anomaly, we analyzed subsurface density structures along 13 northeastern-southwestern profiles and 35 northwestern-southeastern profiles with the interval of 2 km using the two dimensional Talwani's method (Talwani et al., 1959). In the analysis, we assumed a density structure with four layers: basement (density is 2670kg/m3), Neocene volcanic rock (density is 2400kg/m3, or 2550kg/m3), Neocene sedimentary rock (density is 2200kg/m3), and Quaternary sedimentary rock (density is 1800kg/m3, or 1500kg/m3) (Honda et al., 2008). To compare our basement model to the geological block structures, we focus on a transition zone of the basement depth. We recognize that two of three geological block boundaries correspond to the transition zones. These boundaries also correspond to the boundary of active fault segments on the seafloor. Therefore, based on the relationship between the source fault of the 2007 Noto Hanto earthquake and the geological block, we suggest that the movement of those geological blocks is possibly controlled by the corresponding active fault segments. However, we find that the other block boundary doesn't correspond to the transition zone.

Mizubayashi, T.; Sawada, A.; Hamada, M.; Hiramatsu, Y.; Honda, R.

2012-12-01

277

Model-based clustering reveals vitamin D dependent multi-centrality hubs in a network of vitamin-related proteins  

PubMed Central

Background Nutritional systems biology offers the potential for comprehensive predictions that account for all metabolic changes with the intricate biological organization and the multitudinous interactions between the cellular proteins. Protein-protein interaction (PPI) networks can be used for an integrative description of molecular processes. Although widely adopted in nutritional systems biology, these networks typically encompass a single category of functional interaction (i.e., metabolic, regulatory or signaling) or nutrient. Incorporating multiple nutrients and functional interaction categories under an integrated framework represents an informative approach for gaining system level insight on nutrient metabolism. Results We constructed a multi-level PPI network starting from the interactions of 200 vitamin-related proteins. Its final size was 1,657 proteins, with 2,700 interactions. To characterize the role of the proteins we computed 6 centrality indices and applied model-based clustering. We detected a subgroup of 22 proteins that were highly central and significantly related to vitamin D. Immune system and cancer-related processes were strongly represented among these proteins. Clustering of the centralities revealed a degree of redundancy among the indices; a repeated analysis using subsets of the centralities performed well in identifying the original set of 22 most central proteins. Conclusions Hierarchical and model-based clustering revealed multi-centrality hubs in a vitamin PPI network and redundancies among the centrality indices. Vitamin D-related proteins were strongly represented among network hubs, highlighting the pervasive effects of this nutrient. Our integrated approach to network construction identified promiscuous transcription factors, cytokines and enzymes - primarily related to immune system and cancer processes - representing potential gatekeepers linking vitamin intake to disease.

2011-01-01

278

Involvement of PLEKHM1 in osteoclastic vesicular transport and osteopetrosis in incisors absent rats and humans  

PubMed Central

This study illustrates that Plekhm1 is an essential protein for bone resorption, as loss-of-function mutations were found to underlie the osteopetrotic phenotype of the incisors absent rat as well as an intermediate type of human osteopetrosis. Electron and confocal microscopic analysis demonstrated that monocytes from a patient homozygous for the mutation differentiated into osteoclasts normally, but when cultured on dentine discs, the osteoclasts failed to form ruffled borders and showed little evidence of bone resorption. The presence of both RUN and pleckstrin homology domains suggests that Plekhm1 may be linked to small GTPase signaling. We found that Plekhm1 colocalized with Rab7 to late endosomal/lysosomal vesicles in HEK293 and osteoclast-like cells, an effect that was dependent on the prenylation of Rab7. In conclusion, we believe PLEKHM1 to be a novel gene implicated in the development of osteopetrosis, with a putative critical function in vesicular transport in the osteoclast.

Van Wesenbeeck, Liesbeth; Odgren, Paul R.; Coxon, Fraser P.; Frattini, Annalisa; Moens, Pierre; Perdu, Bram; MacKay, Carole A.; Van Hul, Els; Timmermans, Jean-Pierre; Vanhoenacker, Filip; Jacobs, Ruben; Peruzzi, Barbara; Teti, Anna; Helfrich, Miep H.; Rogers, Michael J.; Villa, Anna; Van Hul, Wim

2007-01-01

279

Force Eruption of Mandibular Second Incisor in an 11- Year Old Boy: A Technical Report  

PubMed Central

There is a great challenge in the treatment of deeply fractured and un-restorable teeth among dentists. Orthodontic force eruption is a method of treatment for these teeth to preserve natural root system and periodontal structures. This technical report is a new modification of this procedure presented in an 11- year old boy with deeply fractured left second mandibular incisor. The fractured teeth were treated with root canal therapy and a file #80 was modified to become a hook cemented into the fractured tooth. Anterior teeth were splinted and used as anchorage to help the root extrusion. 1-year follow up of the tooth showed the convenience of the treatment. This simple and low-cost method can be an acceptable alternative to the current high cost techniques, achieving the same results.

Sobhnamayan, F; Moazami, F; Hamedi, S; Meshki, R

2013-01-01

280

Force eruption of mandibular second incisor in an 11- year old boy: a technical report.  

PubMed

There is a great challenge in the treatment of deeply fractured and un-restorable teeth among dentists. Orthodontic force eruption is a method of treatment for these teeth to preserve natural root system and periodontal structures. This technical report is a new modification of this procedure presented in an 11- year old boy with deeply fractured left second mandibular incisor. The fractured teeth were treated with root canal therapy and a file #80 was modified to become a hook cemented into the fractured tooth. Anterior teeth were splinted and used as anchorage to help the root extrusion. 1-year follow up of the tooth showed the convenience of the treatment. This simple and low-cost method can be an acceptable alternative to the current high cost techniques, achieving the same results. PMID:24724126

Sobhnamayan, F; Moazami, F; Hamedi, S; Meshki, R

2013-06-01

281

The effects of spaceflight on the mineralization of rat incisor dentin  

NASA Technical Reports Server (NTRS)

Specific effects of space flight on dentin formation on the lower incisors of male rats were determined. Data were Fourier analyzed to determine the spectra of chemical growth rhythms. It was found that Calcium and P were more concentrated in the newly forming dentin of the Flight rats than in comparable regions of control tissues. There was no significant difference in the mean S-concentration between the two groups, but the pattern of S-distribution in the recently formed dentin from the Flight rats was different from that in the control group. Sulfur fluctuations in flight animals periodically peak above the irregular background fluctuations, but there are no comparable sulfur peaks across the dentin in the control. It is indicated that spaceflight has measurable effects on dentinogenesis, and may also bear on the problem of the regulatory role of proteoglycans in mineralization and the maturation of mineral and matrix moieties in skeletal tissue.

Simmons, D. J.; Rosenberg, G. D.

1984-01-01

282

New Reforms in the Management of the University: Transition from Centralized to Decentralized (University-Based Management) in Iran  

ERIC Educational Resources Information Center

This article focuses on new reforms in Iran's higher education management system--Transition from centralized to decentralized (University-Based management--UBM). This is an important subject since Iran's Ministry of Science, Research, and Technology (MSRT) has begun to introduce new reforms for the improvement and the enhancement of Iranian…

Mehralizadeh, Y.

2005-01-01

283

Soil microbial activities in tree-based cropping systems and natural forests of the Central Amazon, Brazil  

Microsoft Academic Search

Little information is available about the factors controlling soil C and N transformations in natural tropical forests and tree-based cropping systems. The aim of this work was to study the effects of single trees on soil microbiological activities from plantations of timber and non-timber species as well as species of primary and secondary forests in the Central Amazon. Soil samples

Oleg V. Menyailo; Johannes Lehmann; Manoel da Silva Cravo; Wolfgang Zech

2003-01-01

284

The monitor and control system for the grain depot based on the algorithm of flexible logic centralized fusion  

Microsoft Academic Search

During the storage of grain, its quality can be influenced by temperature, humidity, oxygen, microorganisms, insects and other factors. It is necessary to protect the storage quality of grain through real-time monitoring these parameters and analyzing their influences. An algorithm is proposed based on flexible logic centralized fusion to study the evaluation method of overall temperature in grain heap. According

Xingxing Cheng; Zhixiao Yang; Dexian Zhang

2010-01-01

285

Routine treatment of bilateral aplasia of upper lateral incisors by orthodontic space closure without mandibular extractions.  

PubMed

This study aimed to gather statistically validated information on the changes in orthodontic variables in patients with bilateral upper lateral incisor aplasia treated with isolated orthodontic space closure. Data were collected from 25 (15 females, 10 males) consecutively treated, unselected adolescents [mean age at the end of treatment 16.4 years, standard deviation (SD) 1.3] after orthodontic space closure using push-and-pull mechanics (PPM). The changes in the relevant parameters were determined by comparing baseline and final lateral headfilms and casts. Following verification of normal distribution by means of a Kolmogorov-Smirnov test, a two-tailed t-test for related data was performed. SNA, ANB, OcP-NL, OcP-ML, upper space balance, overbite, overjet, bilateral molar relationship, and L1-NB changed significantly (P < or = 0.05) during treatment. The changes in overbite, overjet, spatial conditions, and molar relationship were in line with the targeted treatment objectives and within the normal range. Although the change in L1-NB was probably due to treatment, it was not clinically relevant given that the mean final values were close to normal at 22.8 degrees (SD 5.8 degrees ) for L1-NB and 95 degrees (SD 8 degrees ) for L1-ML. Isolated orthodontic space closure for bilateral upper lateral incisor aplasia using PPM can be regarded as a valid alternative to prosthetic solutions. Long-term use of Class III elastics does not lead to significant changes in relevant orthodontic parameters. PMID:19147810

Zimmer, Bernd; Seifi-Shirvandeh, Nasrin

2009-06-01

286

Effect of interrupted eruption on the enamel organ of the rat incisor.  

PubMed

The aim of this study was to investigate the behavior of rat incisor tissues during the inhibition of tooth eruption. Twenty Sprague-Dawley rats were used in this study, and incisor eruption was inhibited by a screw pin. Animals were sacrificed 1, 3, 7 and 14 days after the start of the experiment. Cross-sections at the mesial point of the mandibular first molar and sagittal sections of the mandibular tooth germ area were examined using immunohistochemical and immunofluorescence methods. For morphometric analysis, numbers of TRAP-positive cells were calculated against the total number of cells. In cross-sections from the experimental group, dentin was thickened and pulp tissue was constricted day by day. On days 1, 3 and 7, nestin-positive cells were observed in all odontoblast cell bodies and processes, while on day 14 fewer nestin-positive cells were seen than in the control group. On day 14, the mesial area of the periodontal ligament was constricted and the number of TRAP-positive cells in the mesial area was significantly higher than in the control group. In sagittal sections, enamel formation was found to be increased on days 7 and 14. Furthermore, in the enamel matrix amelogenin was expressed more strongly than in the control group. PCNA-positive cells were significantly increased in cells of the tooth germ compared with the control group. These results suggest that inhibition of tooth eruption accelerates the apical elongation with resorption of the mesial area of the alveolar bone and stimulates cell proliferation with thickened enamel towards the apical end. PMID:23433861

Miwa, Tsuneyuki; Matsuzaka, Kenichi; Inoue, Takashi

2013-04-01

287

Rock glacier analyses in the Tyrolean Central Alps based on airborne lidar-data  

NASA Astrophysics Data System (ADS)

Airborne LIDAR-datasets offer a high potential for the monitoring of surface changes within high mountain environments. Based on an analysis of rock glaciers with airborne LIDAR-datasets a rock glacier activity index is developed. The results are then compared to the classified rock glacier activities from the Tyrolean rock glacier inventory. LIDAR-data from 2006 and 2010 are used to generate bi-temporal, high-resolution DTMs, for more than 400 rock glaciers in the Tyrolean Central Alps (Austria) that cover an area of 750 qkm. The differential DTMs are used to identify basic processes on rock glacier surfaces including vertical and horizontal displacement rates. In order to calculate the vertical displacement rates the DTMs from 2006 are subtracted from 2010 DTMs, whereas the velocities are calculated by image matching. Based on the DTMs the mean and standard deviation of the surface elevation changes and the surface velocities are calculated for each rock glacier. The accuracy of the results of the surface elevation change calculations is improved by applying a simple stable area approach. This approach allows to correct the systematic error between the bi-temporal DTMs, yielding a higher accuracy for the vertical displacement rates. By combining the normalized mean and standard deviation of the surface elevation changes and velocities, a rock glacier activity index is developed. The activity index ranges from values between zero and one indicating low and high activity rates for each rock glacier. A clear trend between the activity index and the rock glacier inventory is found. Most of the active classified rock glaciers show a high activity index with values exceeding 0.4 and most of the fossil classified rock glaciers show a low activity index with values around zero. Discrepancies between the two methods, the developed rock glacier activity index and the prior manual rock glacier classification, will be discussed. The activity index is in good agreement with the standard classification of an already existing rock glacier inventory. This activity index offers new possibilities in rock glacier research towards an independently reproducible and quantitative airborne lidar based classification.

Girstmair, A.; Sailer, R.; Bollmann, E.; Stötter, J.; Krainer, K.

2012-12-01

288

Rock glacier analyses in the Tyrolean Central Alps based on airborne lidar-data  

NASA Astrophysics Data System (ADS)

Airborne LIDAR-datasets offer a high potential for the monitoring of surface changes within high mountain environments. Based on an analysis of rock glaciers with airborne LIDAR-datasets a rock glacier activity index is developed. The results are then compared to the classified rock glacier activities from the Tyrolean rock glacier inventory. LIDAR-data from 2006 and 2010 are used to generate bi-temporal, high-resolution DTMs, for more than 400 rock glaciers in the Tyrolean Central Alps (Austria). The differential DTMs are used to identify basic processes on rock glacier surfaces including vertical and horizontal displacement rates. In order to calculate the vertical displacement rates the DTMs from 2006 are subtracted from 2010 DTMs, whereas the velocities are calculated by image matching. Based on the DTMs the mean and standard deviation of the surface elevation changes and the surface velocities are calculated for each rock glacier. The accuracy of the results of the surface elevation change calculations is improved by applying a simple stable area approach. This approach allows to correct the systematic error between the bi-temporal DTMs, yielding a higher accuracy for the vertical displacement rates. By combining the normalized mean and standard deviation of the surface elevation changes and velocities, a rock glacier activity index is developed. The activity index ranges from values between zero and one indicating low and high activity rates for each rock glacier. A clear trend between the activity index and the rock glacier inventory is found. Most of the active classified rock glaciers show a high activity index with values exceeding 0.4 and most of the fossil classified rock glaciers show a low activity index with values around zero. Discrepancies between the two methods, the developed rock glacier activity index and the prior manual rock glacier classification, will be discussed. The activity index is in good agreement with the standard classification of an already existing rock glacier inventory. This activity index offers new possibilities in rock glacier research towards an independently reproducible and quantitative airborne lidar based classification.

Girstmair, Anna; Mitterer-Hoinkes, Susanna; Bollmann, Erik; Krainer, Karl; Sailer, Rudolf; Stötter, Johann

2013-04-01

289

An EO-Based Approach to Modelling Ecosystem Health in Response to Wildfire in Central Greece  

NASA Astrophysics Data System (ADS)

Assessment of ecosystem health is becoming more relevant in a world where ecosystems are being used unsustainably and have been showing increased signs of stress and dysfunction. Therefore, this research has set out to establish an Earth Observation (EO) based methodology in conjunction with Geographical Information Systems (GIS) to establish and monitor the indicators of ecosystem health in a region affected by wildfire in Central Greece. A further goal has been to assess the responses of ecosystem health to wildfire and urban expansion in the studied region. The methodology integrated GIS software and EO data to assess ecosystem characteristics including: vigour, organisation and resilience. The characteristics were quantified using remote sensing techniques focusing on Normalised Difference Vegetation Index (NDVI) images derived from Landsat imagery from 1999-2011. Topographic features including slope and aspect were extracted from a digital elevation model (DEM). These elements were then assigned weightings based upon research and combined in a model to produce a map of ecosystem health. The map of ecosystem health was validated against a compound topographic index that was produced for the study region, completed by overlaying the layers in Google Earth. This software allowed for a direct comparison of each layer. The results of the model have demonstrated correlations with past wildfires and the associated recovery. The findings are in agreement with the hypothesis that ecosystem health maps can illustrate the effect wildfires have on ecosystem health, thus providing useful information to land managers and policy makers who manage wildfire. The results further demonstrate that the resolution of Landsat imagery is excellent for obtaining a general overview of ecosystem health mapping. The methods described in this study could provide more detailed information if applied to high resolution imagery such as Worldview or IKONOS data. Results could be further enhanced with hyperspectral sensors due to the possibility of detecting chemical processes associated with ecosystem process. The method is robust enough to be transferable to other regions, with some minor changes based on a specified climate for a given location. The launch of Landsat 8 will ensure the continued acquisition and availability of Landsat data as well as provide high quality images, also making it possible to develop this method to potentially contribute to an operational estimation of ecosystem health recovery after wildfire.

Evans, Aaron; Petropoulos, George P.

2014-05-01

290

Attenuation Tomography Based on Strong Motion Data: Case Study of Central Honshu Region, Japan  

NASA Astrophysics Data System (ADS)

Three-dimensional frequency dependent S-wave quality factor (Q?(f)) value for the central Honshu region of Japan has been determined in this paper using an algorithm based on inversion of strong motion data. The method of inversion for determination of three-dimensional attenuation coefficients is proposed by H ashida and S himazaki (J Phys Earth. 32, 299-316, 1984) and has been used and modified by J oshi (Curr Sci. 90, 581-585, 2006; Nat Hazards. 43, 129-146, 2007) and J oshi et al. (J. Seismol. 14, 247-272, 2010). Twenty-one earthquakes digitally recorded on strong motion stations of Kik-net network have been used in this work. The magnitude of these earthquake ranges from 3.1 to 4.2 and depth ranging from 5 to 20 km, respectively. The borehole data having high signal to noise ratio and minimum site effect is used in the present work. The attenuation structure is determined by dividing the entire area into twenty-five three-dimensional blocks of uniform thickness having different frequency-dependent shear wave quality factor. Shear wave quality factor values have been determined at frequencies of 2.5, 7.0 and 10 Hz from record in a rectangular grid defined by 35.4°N to 36.4°N and 137.2°E to 138.2°E. The obtained attenuation structure is compared with the available geological features in the region and comparison shows that the obtained structure is capable of resolving important tectonic features present in the area. The proposed attenuation structure is compared with the probabilistic seismic hazard map of the region and shows that it bears some remarkable similarity in the patterns seen in seismic hazard map.

Kumar, Parveen; Joshi, A.; Verma, O. P.

2013-12-01

291

Epidemiology of Idiopathic Central Serous Chorioretinopathy in Taiwan, 2001-2006: A Population-based Study  

PubMed Central

Objectives The epidemiology of idiopathic central serous chorioretinopathy (CSCR) is not well understood in an Asian population. The present study aimed to investigate the incidence and risk factors for corticosteroid-unrelated CSCR using Taiwan’s National Health Insurance Research Database. Methods and Results From 2001 to 2006, a total of 786 patients (500 [63.6%] males) who were newly diagnosed with CSCR, aged from 20 to 64 years and had no history of corticosteroid prescription were identified as incident cases of idiopathic CSCR. 3606 age-, gender-, and enrollment time-matched subjects were randomly selected as the control group. The mean annual incidence was 0.21‰ (0.27‰ for males, and 0.15‰ for females; P<0.001), with a male/female ratio of 1.74. The peak incidence was in the 35- to 39-year-old age group (0.30‰), followed by the 40- to 44-year-old age group (0.26‰). Males had a significantly higher mean annual incidence than female only in the middle age groups. Conditional logistic regression was used to estimate the odds ratios (ORs) for potential risk factors of idiopathic CSCR. Only exposure to anti-anxiety drugs (OR, 1.63; 95% confidence interval, 1.09–2.44) was found to be independently associated with idiopathic CSCR among males. No risk factors of idiopathic CSCR were found for females. Conclusions This study provides the nationwide, population-based data on the incidence of idiopathic CSCR in adult Asians, and suggests that exposure to anti-anxiety drugs is an independent risk factor for idiopathic CSCR among males.

Tsai, Der-Chong; Chen, Shih-Jen; Huang, Chin-Chou; Chou, Pesus; Chung, Chia-Min; Huang, Po-Hsun; Lin, Shing-Jong; Chen, Jaw-Wen; Chen, Tseng-Ji

2013-01-01

292

Deep sounding TEM investigation method based on a modified fixed central-loop system  

NASA Astrophysics Data System (ADS)

The central-loop TEM technology has been widely used in mineral exploration, engineering and environmental investigations and assorted geologic studies. For easy and efficient working conditions, a square (or rectangular) loop is generally employed instead of a circular one. Any position within the inner one ninth of the central part of the loop is often designated as the central survey location (within which the field is assumed to be uniform), and referred to as a modified central-loop configuration. However, the deduced field parameters at such non-central positions when calculated by a central-loop formula result in decreased accuracy and possibly erroneous interpretation. A large-fixed loop offers the advantage of being able to determine the induced potential at any point inside or outside the loop. In this study we provide the formula for the large-fixed loop and receiver positions within the modified central-loop system and solve the problem. Specifically, we compute the electromagnetic response of any field point by using an electric dipole integration method. The full time-domain apparent resistivity values are then extracted by using an iterative method. Both theoretical modeling and real data examples indicate that such a configuration not only improves the accuracy for the TEM survey, but also enlarges the exploration depth, due to a large loop used in the deployment. The method is used for locating the water enriched areas in coal mines in Yangquan region of Shanxi province and in Bin County of Shaanxi province, China. The interpreted results are tested by later drilling, which confirmed our combined method to be a reliable and efficient method for deep sounding.

Xue, Guo-qiang; Bai, Chao-ying; Yan, Shu; Greenhalgh, Stewart; Li, Mei-fang; Zhou, Nan-nan

2012-01-01

293

Crustal architecture of central Australia based on deep seismic reflection profiling  

NASA Astrophysics Data System (ADS)

The crustal architecture of central Australia is interpreted from deep seismic reflection profiling conducted by the Australian Geological Survey Organisation in two surveys in 1985 and 1993. The seismic traverses, oriented normal to the main surface structures, ran north-south in central Australia, and crossed parts of the Arunta Block, Amadeus Basin, Musgrave Block and Officer Basin. The present crustal fabric was set in place by the end of the Mesoproterozoic (by about 1100 Ma). Reactivation of the structures took place in a continental intraplate setting mainly during the Middle-Late Palaeozoic Alice Springs Orogeny, but also during other orogenic events. In the Arunta Block. the crust is dominated by major north-dipping planar structures, interpreted as thick-skinned thrusts. Many of these thrusts cut deep into the crust, and at least one, the Redbank Thrust Zone, appears to cut and offset the Moho. In contrast, in the northern Musgrave Block, limited field mapping and teleseismic data suggest that the major crustal-scale planar structures are south-dipping. In the central to southern Amadeus Basin, deformation is essentially thin-skinned, with north-directed thrusting confined to the sedimentary succession. Thus, the deep seismic profiles in central Australia show a present day crustal architecture that is the response of the crust to Mesoproterozoic terrane amalgamation and to later reactivation by intraplate deformational events. Therefore. central Australia is a model for intraplate cratonic deformation that occurs in continental crust that is cold. thick and strong.

Korsch, R. J.; Goleby, B. R.; Leven, J. H.; Drummond, B. J.

1998-03-01

294

How accurate and statistically robust are catalytic site predictions based on closeness centrality?  

PubMed Central

Background We examine the accuracy of enzyme catalytic residue predictions from a network representation of protein structure. In this model, amino acid ?-carbons specify vertices within a graph and edges connect vertices that are proximal in structure. Closeness centrality, which has shown promise in previous investigations, is used to identify important positions within the network. Closeness centrality, a global measure of network centrality, is calculated as the reciprocal of the average distance between vertex i and all other vertices. Results We benchmark the approach against 283 structurally unique proteins within the Catalytic Site Atlas. Our results, which are inline with previous investigations of smaller datasets, indicate closeness centrality predictions are statistically significant. However, unlike previous approaches, we specifically focus on residues with the very best scores. Over the top five closeness centrality scores, we observe an average true to false positive rate ratio of 6.8 to 1. As demonstrated previously, adding a solvent accessibility filter significantly improves predictive power; the average ratio is increased to 15.3 to 1. We also demonstrate (for the first time) that filtering the predictions by residue identity improves the results even more than accessibility filtering. Here, we simply eliminate residues with physiochemical properties unlikely to be compatible with catalytic requirements from consideration. Residue identity filtering improves the average true to false positive rate ratio to 26.3 to 1. Combining the two filters together has little affect on the results. Calculated p-values for the three prediction schemes range from 2.7E-9 to less than 8.8E-134. Finally, the sensitivity of the predictions to structure choice and slight perturbations is examined. Conclusion Our results resolutely confirm that closeness centrality is a viable prediction scheme whose predictions are statistically significant. Simple filtering schemes substantially improve the method's predicted power. Moreover, no clear effect on performance is observed when comparing ligated and unligated structures. Similarly, the CC prediction results are robust to slight structural perturbations from molecular dynamics simulation.

Chea, Eric; Livesay, Dennis R

2007-01-01

295

Geodiversity of the Umbria region (central Italy): a GIS-based quantitative index  

NASA Astrophysics Data System (ADS)

The measure of natural range related to geological bedrock, landforms and geomorphological processes is the necessary starting point to geodiversity evaluation. Geodiversity plays a strategic role in landscape management. Whereas geotourism and geosites are identified as a driving power for the scientific and economic promotion of an area, the geodiversity knowledge is required for a complete and accurate research. For example, high values of this abiotic parameter identify and support the foundation of geoparks. According to this perspective, the geodiversity is the unifying factor for these areas of interest. While a subjective and qualitative approach may be adequate for geosites definition, identification and cultural promotion, the geodiversity concept needs a different evaluation method. A quantitative procedure allows achieving an objective and repeatable process exportable in different geographic units. Geographical Information Systems and spatial analysis techniques are the base to quantitative evaluation involving topographic, geological and geomorphological data. Therefore, the assessment of a numerical index derived from the overlay of spatial parameters can be conveniently computed in GIS environment. In this study, a geodiversity index is proposed where geological, geomorphological and landcover factors deriving mainly from maps and field survey; topographic ones are employed from DEM and remote sensed data. Each abiotic parameter is modelled in a grid format; focal functions do provide neighbourhood analysis and computing variety statistics. A particular extent is dedicated to topographic information and terrain roughness, that are strictly related to efficiency of geomorphological processes and generally corresponding to the abiotic components variability. The study area is located in central Italy and is characterized by a well known natural heritage. Thirty-seven geosites are detected in the Umbria region, where seven regional and one natural parks are present. All the area shows a strong correlation between the geological setting and the relief energy associated to topography assessment. Three main outcrop complexes are present: a fluvial lacustrine, where the lowest slope values and plain area are widespread; a terrigenous one, with a medium slope value; and a calcareous complex corresponding to the mountain areas and the highest amplitude of relief. This partition matches different geomorphological processes and landforms, ensuring a widespread distribution of geodiversity. The final map is a digital data that localizes areas with, respectively, null or minimum, medium, and high geodiversity values. The highest class overlaps to geosites areas, to high values of amplitude of relief and where the geomorphological processes are more effective and various. This confirms the method accuracy. The results obtained represent an important advancement in geodiversity research and a significant instrument for economic development and conservation management.

Melelli, Laura; Pica, Alessia; Del Monte, Maurizio

2014-05-01

296

Catheter-based renal sympathetic denervation improves central hemodynamics and arterial stiffness: a pilot study.  

PubMed

Renal sympathetic denervation (RDN) is a novel treatment strategy for patients with resistant arterial hypertension. Recently, the Symplicity trials demonstrated significant peripheral blood pressure (BP) reduction. The present study aimed at measuring central aortic pressures and arterial stiffness as better predictors for cardiovascular risk in patients undergoing RDN. RDN was performed in 21 patients (systolic peripheral BP ?150 mm Hg) with an Ardian/Medtronic (Mountain View, CA) ablation system. Data were recorded with an Arteriograph. After 6 months, peripheral systolic BP was reduced by 6.1% (P<.05) while central systolic pressure was reduced by 7.0% (P<.05). Subgroup analysis showed that in responders, peripheral systolic BP was reduced by 16.1% (P<.01) while central systolic pressure was reduced by 18.3% (P<.01). Arterial stiffness improved significantly. Aortic augmentation index (AIx) improved by 9.5% (P<.05). In responders, AIx improved by 19.2% (P<.02). Pulse wave velocity (PWV) was high at baseline (10.8 m/s) and improved by 10.4% (P<.05). In responders, PWV improved by 13.7% (P<.05). Multivariate analysis showed that short-term effects on PWV were BP-related, whereas during follow-up, improvement of PWV becomes BP-unrelated. RDN improves peripheral and central blood pressure as well as arterial stiffness and, thus, may improve cardiovascular outcome. PMID:23205753

Mortensen, Kai; Franzen, Klaas; Himmel, Frank; Bode, Frank; Schunkert, Heribert; Weil, Joachim; Reppel, Michael

2012-12-01

297

A Centralized, Computerized, and Relational Data Base for Student Clinical Placements.  

ERIC Educational Resources Information Center

A centralized relational database is used to manage information on advanced practice nursing students and their preceptors at Johns Hopkins University. The system relieves faculty of time-consuming tasks and enables rapid report generation, consistent tracking, and timely communications. (SK)

Lears, Mary Kathleen; Olsen, Sharon J.; Morrison, Candis; Vessey, Judith A.

1998-01-01

298

A gene expression atlas of the central nervous system based on bacterial artificial chromosomes  

Microsoft Academic Search

The mammalian central nervous system (CNS) contains a remarkable array of neural cells, each with a complex pattern of connections that together generate perceptions and higher brain functions. Here we describe a large-scale screen to create an atlas of CNS gene expression at the cellular level, and to provide a library of verified bacterial artificial chromosome (BAC) vectors and transgenic

Shiaoching Gong; Chen Zheng; Martin L. Doughty; Kasia Losos; Nicholas Didkovsky; Uta B. Schambra; Norma J. Nowak; Alexandra Joyner; Gabrielle Leblanc; Mary E. Hatten; Nathaniel Heintz

2003-01-01

299

Central Nervous System Based Neurogenic Female Sexual Dysfunction: Current Status and Future Trends  

Microsoft Academic Search

The amount of information available regarding the impact of various central nervous system disorders on female sexual function has greatly increased. In this article, the most recent information regarding brain and spinal cord disorders in human females is reviewed. Evidence from women with spinal cord injuries (SCIs) supports findings in able-bodied females that the sympathetic nervous system provides regulation of

Marca L. Sipski

2002-01-01

300

Prediction of central nervous system embryonal tumour outcome based on gene expression  

Microsoft Academic Search

Embryonal tumours of the central nervous system (CNS) represent a heterogeneous group of tumours about which little is known biologically, and whose diagnosis, on the basis of morphologic appearance alone, is controversial. Medulloblastomas, for example, are the most common malignant brain tumour of childhood, but their pathogenesis is unknown, their relationship to other embryonal CNS tumours is debated, and patients'

Scott L. Pomeroy; Pablo Tamayo; Michelle Gaasenbeek; Lisa M. Sturla; Michael Angelo; Margaret E. McLaughlin; John Y. H. Kim; Liliana C. Goumnerova; Peter M. Black; Ching Lau; Jeffrey C. Allen; David Zagzag; James M. Olson; Tom Curran; Cynthia Wetmore; Jaclyn A. Biegel; Tomaso Poggio; Shayan Mukherjee; Ryan Rifkin; Andrea Califano; Gustavo Stolovitzky; David N. Louis; Jill P. Mesirov; Eric S. Lander; Todd R. Golub

2002-01-01

301

Fiber-reinforced framework in conjunction with porcelain veneers for the esthetic replacement of a congenitally missing maxillary lateral incisor: a case study.  

PubMed

This article presents a case of a congenitally missing right maxillary lateral incisor and the contralateral incisor with discolored composite resin restorations. The technique of fiber reinforcement in conjunction with porcelain veneers was used to provide a satisfactory outcome for the patient. The key learning points of the article are the following: proper diagnosis, treatment plan and appropriate utilization of materials are mandatory for a successful result. PMID:22621164

Benito, P P; Trushkowsky, R D; Magid, K S; David, S B

2012-01-01

302

Influence of fatigue testing and cementation mode on the load-bearing capability of bovine incisors restored with crowns and zirconium dioxide posts  

Microsoft Academic Search

The aim of the study was to evaluate the influence of fatigue and cementation mode on the fracture behavior of endodontically\\u000a treated bovine incisors restored with zirconium dioxide posts and crowns. Forty-eight endodontically treated bovine primary\\u000a incisors were restored with zirconium dioxide posts (Cerapost, Brasseler), composite build-ups, and crowns cast from a chromium\\u000a cobalt alloy. In 16 teeth, each of

F. P. Nothdurft; T. Schmitt; P. J. Motter; P. R. Pospiech

2008-01-01

303

Analysis of Solvent Central Nervous System Toxicity and Ethanol Interactions Using a Human Population Physiologically Based Kinetic and Dynamic Model  

Microsoft Academic Search

The effect of acute ethanol-mediated inhibition of m-xylene metabolism on central nervous system (CNS) depression in the human worker population was investigated using physiologically based pharmacokinetic (PBPK) models and probabilistic random (Monte Carlo) sampling. PBPK models of inhaled m-xylene and orally ingested ethanol were developed and combined by a competitive enzyme (CYP2E1) inhibition model. Human interindividual variability was modeled by

A. J. MacDonald; A. Rostami-Hodjegan; G. T. Tucker; D. A. Linkens

2002-01-01

304

Effect of Growth Hormone on the Distribution of Decorin and Biglycan during Odontogenesis in the Rat Incisor  

Microsoft Academic Search

Previous studies have shown that growth hormone can influence the expression of N-acetylgalactosamine-containing molecules in the extracellular matrix of developing rat incisors. N-acetylgalactosamine is a principal component of proteoglycans containing chondroitin sulfate and dermatan sulfate, as well as of some glycoproteins. Since chondroitin sulfate proteoglycans are identifiable components in enamel, dentin, and cementum, we have tested the hypothesis that growth

C. Z. Zhang; H. Li; P. M. Bartold; W. G. Young; M. J. Waters

1995-01-01

305

Dendritic Cells: A Novel Cellular Component of the Rat Incisor Enamel Organ Appearing in the Late Stages of Enamel Maturation  

Microsoft Academic Search

Immunocompetent cells in the enamel organ of rat incisors were examined immunohistochemically using OX6, ED1, and ED2 monoclonal antibodies known to recognize the Class II MHC molecules, a monocyte-macrophage lineage, and residential macrophages, respectively. The OX6 immunopositive cells (MHC cells) were located exclusively in the enamel maturation zone. MHC cells increased in number in the incisal direction and occasionally extended

Y. Takano; I. Kawahara; M. Hoshino; K. Takeuchi; T. Maeda; H. Ohshima; Y. Hanaizumi; Y. Kawano

1996-01-01

306

Core binding factor beta functions in the maintenance of stem cells and orchestrates continuous proliferation and differentiation in mouse incisors.  

PubMed

Rodent incisors grow continuously throughout life, and epithelial progenitor cells are supplied from stem cells in the cervical loop. We report that epithelial Runx genes are involved in the maintenance of epithelial stem cells and their subsequent continuous differentiation and therefore growth of the incisors. Core binding factor ? (Cbfb) acts as a binding partner for all Runx proteins, and targeted inactivation of this molecule abrogates the activity of all Runx complexes. Mice deficient in epithelial Cbfb produce short incisors and display marked underdevelopment of the cervical loop and suppressed epithelial Fgf9 expression and mesenchymal Fgf3 and Fgf10 expression in the cervical loop. In culture, FGF9 protein rescues these phenotypes. These findings indicate that epithelial Runx functions to maintain epithelial stem cells and that Fgf9 may be a target gene of Runx signaling. Cbfb mutants also lack enamel formation and display downregulated Shh mRNA expression in cells differentiating into ameloblasts. Furthermore, Fgf9 deficiency results in a proximal shift of the Shh expressing cell population and ectopic FGF9 protein suppresses Shh expression. These findings indicate that Shh as well as Fgf9 expression is maintained by Runx/Cbfb but that Fgf9 antagonizes Shh expression. The present results provide the first genetic evidence that Runx/Cbfb genes function in the maintenance of stem cells in developing incisors by activating Fgf signaling loops between the epithelium and mesenchyme. In addition, Runx genes also orchestrate continuous proliferation and differentiation by maintaining the expression of Fgf9 and Shh mRNA. PMID:21898689

Kurosaka, Hiroshi; Islam, Md Nurul; Kuremoto, Koh-Ichi; Hayano, Satoru; Nakamura, Masahiro; Kawanabe, Noriaki; Yanagita, Takeshi; Rice, David P C; Harada, Hidemitsu; Taniuchi, Ichiro; Yamashiro, Takashi

2011-11-01

307

Mandibular lateral incisor with four root canals: A unique case of double tooth diagnosed using multidetector computed tomography  

PubMed Central

Double tooth is a dental anomaly consequent to fusion of two or more teeth or gemination of a single tooth. This report describes a unique case of double tooth in relation to a mandibular lateral incisor exhibiting the presence of four root canals. The role of conventional radiography and advanced three-dimensional imaging techniques in the better assessment of complex root canal systems and their aid in endodontic management has also been highlighted.

Gupta, Sunil Kumar; Acharya, Shashi Rashmi; Ather, Amber

2013-01-01

308

Red/near-infrared luminescence tuning of group-14 element complexes of dipyrrins based on a central atom.  

PubMed

A dipyrrin complex has been one of the most utilized fluorescent dyes, and a variety of dipyrrin complexes show intriguing functions based on the various coordination structures of the central element. We now report the synthesis, structure, and photophysical properties of germanium and stannane complexes of the N2O2-type tetradentate dipyrrin, L·Ge and L·Sn, which are heavier analogues of the previously reported dipyrrin silicon complex, L·Si. The central group-14 atoms of the monomeric complexes have geometries close to trigonal bipyramidal (TBP), in which the contribution of the square-pyramidal (SP) character becomes higher as the central atom is heavier. Interestingly, L·Sn formed a dimeric structure in the crystal. All complexes L·Si, L·Ge, and L·Sn showed a fluorescence in the red/NIR region. Fluorescence quantum yields of L·Ge and L·Sn are higher than that of L·Si. These results indicated that the central atom on the dipyrrin complexes contributes not only to the geometry difference but also to tuning the fluorescence properties. PMID:24422462

Yamamura, Masaki; Albrecht, Marcel; Albrecht, Markus; Nishimura, Yoshinobu; Arai, Tatsuo; Nabeshima, Tatsuya

2014-02-01

309

Alpha11 beta1 integrin-dependent regulation of periodontal ligament function in the erupting mouse incisor.  

PubMed

The fibroblast integrin alpha11beta1 is a key receptor for fibrillar collagens. To study the potential function of alpha11 in vivo, we generated a null allele of the alpha11 gene. Integrin alpha11(-/-) mice are viable and fertile but display dwarfism with increased mortality, most probably due to severely defective incisors. Mutant incisors are characterized by disorganized periodontal ligaments, whereas molar ligaments appear normal. The primary defect in the incisor ligament leads to halted tooth eruption. alpha11beta1-defective embryonic fibroblasts displayed severe defects in vitro, characterized by (i) greatly reduced cell adhesion and spreading on collagen I, (ii) reduced ability to retract collagen lattices, and (iii) reduced cell proliferation. Analysis of matrix metalloproteinase in vitro and in vivo revealed disturbed MMP13 and MMP14 synthesis in alpha11(-/-) cells. We show that alpha11beta1 is the major receptor for collagen I on mouse embryonic fibroblasts and suggest that alpha11beta1 integrin is specifically required on periodontal ligament fibroblasts for cell migration and collagen reorganization to help generate the forces needed for axial tooth movement. Our data show a unique role for alpha11beta1 integrin during tooth eruption. PMID:17420280

Popova, Svetlana N; Barczyk, Malgorzata; Tiger, Carl-Fredrik; Beertsen, Wouter; Zigrino, Paola; Aszodi, Attila; Miosge, Nicolai; Forsberg, Erik; Gullberg, Donald

2007-06-01

310

Feasibility study for establishing a centralized geothermal data base for New Mexico. Final report, June 1, 1979-October 15, 1979  

SciTech Connect

The purpose of this work is to catalog the information available and to make recommendations toward improving its accessibility. Existing computerized and non-computerized data sources are identified at both the state and national level. The content and accessibility of each such data base are investigated, as well as its suitability for aiding geothermal development. A catalog of such information is provided for each of the following data sources: GEOTHERM, WATSORE, STORIT, RPPM, GRID, HISS, EID air quality, and EID water quality. The available computing facilities within the state are evaluated for their appropriateness as a central storage facility for the many data sources. Recommendations are made for the establishment of a centralized geothermal/environmental data base. Included are recommendations for the computing facilities to be used by such a data base. How to obtain access to a given data base is described. This includes whether the data base is accessible from within New Mexico, necessary agreements, and contact persons. A glossary of computer-related terms and a brief description of knowledge-based problem-solving are included. (MHR)

Klimowicz, G.; Martin, N.

1980-01-01

311

Development of Multimode Biomimetic Robotic Fish Based on Central Pattern Generator  

Microsoft Academic Search

This paper presents the construction and motion control of a biologically inspired, multi-mode biomimetic robotic fish capable of three-dimensional locomotion. The mechanical configuration and the control system are described. The rhythmic movements of swimming are driven by the biological neural networks, called the central pattern generators (CPGs). The CPGs are modeled as nonlinear oscillators for joints and inter-joint coordination is

Wei Zhao; Junzhi Yu; Yimin Fang; Long Wang

2006-01-01

312

Er:YAG Laser and Fractured Incisor Restorations: An In Vitro Study  

PubMed Central

Introduction. The aim of this study was to analyse the effects of an Er:YAG laser on enamel and dentine in cases of dental restorations involving fractured teeth, utilizing the dental fragment. Materials and Methods. Seventy-two freshly extracted bovine incisors were fractured at the coronal level by using a hammer applied with a standardized method, and the fragment was reattached by using three different methods: Er:YAG laser, orthophosphoric acid, and laser plus acid. The different groups were evaluated by a test realized with the dynamometer to know the force required to successfully detach the reattached fragment and by a microinfiltration test by using a 0.5% methylene blue solution followed by the optic microscope observation. Results. The compression test showed only a slight difference between the three groups, without any statistical significance. The infiltration test used to evaluate the marginal seal between the fracture fragment and the tooth demonstrated that etching with Er:YAG laser alone or in combination with orthophosphoric acid gives better results than orthophosphoric acid alone, with a highly significant statistical result. Discussion. Reattaching a tooth fragment represents a clinically proven methodology, in terms of achieving resistance to detachment, and the aim of this work was to demonstrate the advantages of Er:YAG laser on this procedure. Conclusion. This “in vitro” study confirms that Er:YAG laser can be employed in dental traumatology to restore frontal teeth after coronal fracture.

Fornaini, C.; Petruzzella, S.; Podda, R.; Merigo, E.; Nammour, S.; Vescovi, P.

2012-01-01

313

The design of future central receiver power plants based on lessons learned from the Solar One Pilot Plant  

SciTech Connect

The 10-MW{sub e} Solar One Pilot Plant was the world's largest solar central receiver power plant. During its power production years it delivered over 37,000 MWhrs (net) to the utility grid. In this type of electric power generating plant, large sun-tracking mirrors called heliostats reflect and concentrate sunlight onto a receiver mounted on top a of a tower. The receiver transforms the solar energy into thermal energy that heats water, turning it into superheated steam that drives a turbine to generate electricity. The Solar One Pilot Plant successfully demonstrated the feasibility of generating electricity with a solar central receiver power plant. During the initial 2 years the plant was tested and 4 years the plant was operated as a power plant, a great deal of data was collected relating to the efficiency and reliability of the plant's various systems. This paper summarizes these statistics and compares them to goals developed by the US Department of Energy. Based on this comparison, improvements in the design and operation of future central receiver plants are recommended. Research at Sandia National Laboratories and the US utility industry suggests that the next generation of central receiver power plants will use a molten salt heat transfer fluid rather than water/steam. Sandia has recently completed the development of the hardware needed in a molten salt power plant. Use of this new technology is expected to solve many of the performance problems encountered at Solar One. Projections for the energy costs from these future central receiver plants are also presented. For reference, these projections are compared to the current energy costs from the SEGS parabolic trough plants now operating in Southern California.

Kolb, G.J.

1991-01-01

314

The design of future central receiver power plants based on lessons learned from the Solar One Pilot Plant  

NASA Astrophysics Data System (ADS)

The 10-MW(sub e) Solar One Pilot Plant was the world's largest solar central receiver power plant. During its power production years it delivered over 37,000 MWhrs (net) to the utility grid. In this type of electric power generating plant, large sun-tracking mirrors called heliostats reflect and concentrate sunlight onto a receiver mounted on top of a tower. The receiver transforms the solar energy into thermal energy that heats water, turning it into superheated steam that drives a turbine to generate electricity. The Solar One Pilot Plant successfully demonstrated the feasibility of generating electricity with a solar central receiver power plant. During the initial 2 years the plant was tested and 4 years the plant was operated as a power plant, a great deal of data was collected relating to the efficiency and reliability of the plant's various systems. This paper summarizes these statistics and compares them to goals developed by the U.S. Department of Energy. Based on this comparison, improvements in the design and operation of future central receiver plants are recommended. Research at Sandia National Laboratories and the U.S. utility industry suggests that the next generation of central receiver power plants will use a molten salt heat transfer fluid rather than water/steam. Sandia has recently completed the development of the hardware needed in a molten salt power plant. Use of this new technology is expected to solve many of the performance problems encountered at Solar One. Projections for the energy costs from these future central receiver plants are also presented. For reference, these projections are compared to the current energy costs from the SEGS parabolic trough plants now operating in Southern California.

Kolb, G. J.

315

A simple low-coherence interferometric sensor for absolute position measurement based on central fringe maximum identification  

NASA Astrophysics Data System (ADS)

In this paper, a simple low-coherence interferometric sensor for absolute position measurement based on central fringe maximum identification is presented. The channeled spectrum, captured by a commercial spectrometer, is analyzed by using an algorithm based on the fitting of the calculated autocorrelation function of the captured optical power spectrum with the sum of two Gaussian functions. The position of the central fringe is obtained directly from the separation between two fitted Gaussian functions. In order to boost the precision of such a built sensing system, the position of the maximum of the central fringe is identified by a simple algorithm. The system currently provides unambiguous measurement over a range of 200??m with a mid-range error less than 1.4?nm. In addition to this, the sensor is characterized by a very small sensing head (bare single-mode fiber with a diameter of 125??m) and by very high resistance to environmental influences, thus enabling the possibility of using a very long down-lead sensing fiber.

Manojlovi?, L. M.; Živanov, M. B.; Slankamenac, M. P.; Stupar, D. Z.; Baji?, J. S.

2012-05-01

316

Lithospheric structure of the central Andes based on surface wave dispersion  

NASA Astrophysics Data System (ADS)

Shear wave velocity is very sensitive to temperature anomalies and partial melt and can provide important insights on the state of the lithosphere. With that aim in mind, phase velocities of Rayleigh and Love waves have been inverted for the regionalized shear wave velocity structure of the lithosphere across the central Andes. This inversion reveals strong lateral variations of Vs both across the range and along-strike in the Altiplano crust. In the upper crust, the main features of our models are prominent low-velocity anomalies probably related to partial melt below the Los Frailes ignimbrite complex and the southern Altiplano. At lower crustal level, the Altiplano is characterized by lower Vs than the surrounding regions. We find that the transition from the Altiplano to the Puna is associated with a 7-km thickening of the crust. At mantle depths, the Nazca plate is found to be overlaid by a dipping low-velocity zone with decreasing intensity with depth. Our results favor the idea of a cold mantle lid underlying the whole central Andes.

Baumont, David; Paul, Anne; Zandt, George; Beck, Susan L.; Pedersen, Helle

2002-12-01

317

How long has the central-northern Greenland Ice Sheet been melting at the base?  

NASA Astrophysics Data System (ADS)

Ice-penetrating radar studies (Fahnestock et al., 2001) and the deep ice core project NGRIP (Anderson et al., 2004) have identified extensive areas of rapid basal melt under the central-northern Greenland Ice Sheet (GIS). Our new reconstruction of the lithosphere structure in Greenland reveal that strong anomalies in geothermal heat flux are responsible for much of the estimated ice loss through basal melt. We use our coupled lithosphere-GIS model to study the history of basal ice conditions since the Pliocene period and find that the anomalous heat flow has been maintaining basal ice melt throughout the history of Greenland glaciation. Persistence of basal melt water over the course of ~3.5 million years and periodic development of paleo ice streams originating at the anomaly have likely caused considerable erosion of the subglacial bedrock. The erosion is revealed by ice-penetrating radar measurements, and now exerts a geometric control on ice sheet streaming in the eroded region, and possibly the overall geometry of the GIS. Anderson, K. K., et al. (2004), High-resolution record of Northern Hemisphere climate extending into the last interglacial period, Nature, 431(7005), 147-151 Fahnestock, M., W. Abdalati, I. Joughin, J. Brozena, and P. Gogineni (2001), High geothermal heat flow, basal melt, and the origin of rapid ice flow in central Greenland, Science, 294, 2338-2342

Rogozhina, Irina; Petrunin, Alexey G.; Johnson, Jesse V.; Vaughan, Alan P. M.

2014-05-01

318

Unnatural base pair systems toward the expansion of the genetic alphabet in the central dogma.  

PubMed

Toward the expansion of the genetic alphabet of DNA, several artificial third base pairs (unnatural base pairs) have been created. Synthetic DNAs containing the unnatural base pairs can be amplified faithfully by PCR, along with the natural A-T and G-C pairs, and transcribed into RNA. The unnatural base pair systems now have high potential to open the door to next generation biotechnology. The creation of unnatural base pairs is a consequence of repeating "proof of concept" experiments. In the process, initially designed base pairs were modified to address their weak points. Some of them were artificially evolved to ones with higher efficiency and selectivity in polymerase reactions, while others were eliminated from the analysis. Here, we describe the process of unnatural base pair development, as well as the tests of their applications. PMID:22850726

Hirao, Ichiro; Kimoto, Michiko

2012-01-01

319

Distribution characteristics of the soils in Henan province of central China based on pedodiversity methodology  

NASA Astrophysics Data System (ADS)

A newly developed pedodiversity methodology was used in analyzing the distribution character of the soils in Henan province of central China. The rare soil types and representative soil types were defined after three soil parameters (soil patch numbers, total area and spatial distribution diversity in 2km×2km grid scale) were calculated respectively. Results show that there are positive correlations between soil patch numbers, total area and spatial distribution diversity, the regression equations between spatial distribution diversity and total area is y=0.086ln(x)-0.021, R2=0.992 and y=0.106ln(x)+0.161, R2=0.921 between spatial distribution diversity and patch numbers. The value constituent pattern of soil spatial distribution diversity fits the normal distribution. More attention needs to be paid to protect the endangered rare soil types. The soil type quantity per km2 is always different under different local conditions.

Duan, J. L.; Zhang, X. L.

2014-03-01

320

Genetic and structural analysis of base substitutions in the central pseudoknot of Thermus thermophilus 16S ribosomal RNA  

PubMed Central

Characterization of base substitutions in rRNAs has provided important insights into the mechanism of protein synthesis. Knowledge of the structural effects of such alterations is limited, and could be greatly expanded with the development of a genetic system based on an organism amenable to both genetics and structural biology. Here, we describe the genetic analysis of base substitutions in 16S ribosomal RNA of the extreme thermophile Thermus thermophilus, and an analysis of the conformational effects of these substitutions by structure probing with base-specific modifying agents. Gene replacement methods were used to construct a derivative of strain HB8 carrying a single 16S rRNA gene, allowing the isolation of spontaneous streptomycin-resistant mutants and subsequent genetic mapping of mutations by recombination. The residues altered to give streptomycin resistance reside within the central pseudoknot structure of 16S rRNA comprised of helices 1 and 27, and participate in the U13–U20–A915 base triple, the G21–A914 type II sheared G–A base pair, or the G885–C912 Watson–Crick base pair closing helix 27. Substitutions at any of the three residues engaged in the base triple were found to confer resistance. Results from structure probing of the pseudoknot are consistent with perturbation of RNA conformation by these substitutions, potentially explaining their streptomycin-resistance phenotypes.

Gregory, Steven T.; Dahlberg, Albert E.

2009-01-01

321

Sustainability and Cost of a Community-Based Strategy Against Aedes aegypti in Northern and Central Vietnam  

PubMed Central

We previously reported a new community-based mosquito control that resulted in the elimination of Aedes aegypti in 40 of 46 communes in northern and central Vietnam. During 2007 and 2008, we revisited Nam Dinh and Khanh Hoa provinces in northern and central Vietnam, respectively, to evaluate whether or not these programs were still being maintained 7 years and 4.5 years after formal project activities had ceased, respectively. Using a previously published sustainability framework, we compared 13 criteria from Tho Nghiep commune in Nam Dinh where the local community had adopted our community-based project model using Mesocyclops from 2001. These data were compared against a formal project commune, Xuan Phong, where our successful intervention activities had ceased in 2000 and four communes operating under the National Dengue Control Program with data available. In Khanh Hoa province, we compared 2008 data at Ninh Xuan commune with data at project completion in 2003 and benchmarked these, where possible, against an untreated control commune, Ninh Binh, where few control activities had been undertaken. The three communes where the above community-based strategy had been adopted were rated as well-sustained with annual recurrent total costs (direct and indirect) of $0.28–0.89 international dollars per person.

Kay, Brian H.; Tuyet Hanh, Tran T.; Le, Nguyen Hoang; Quy, Tran Minh; Nam, Vu Sinh; Hang, Phan V. D.; Yen, Nguyen Thi; Hill, Peter S.; Vos, Theo; Ryan, Peter A.

2010-01-01

322

A Common Variation in EDAR Is a Genetic Determinant of Shovel-Shaped Incisors  

PubMed Central

Shovel shape of upper incisors is a common characteristic in Asian and Native American populations but is rare or absent in African and European populations. Like other common dental traits, genetic polymorphisms involved in the tooth shoveling have not yet been clarified. In ectodysplasin A receptor (EDAR), where dysfunctional mutations cause hypohidrotic ectodermal dysplasia, there is a nonsynonymous-derived variant, 1540C (rs3827760), that has a geographic distribution similar to that of the tooth shoveling. This allele has been recently reported to be associated with Asian-specific hair thickness. We aimed to clarify whether EDAR 1540C is also associated with dental morphology. For this purpose, we measured crown diameters and tooth-shoveling grades and analyzed the correlations between the dental traits and EDAR genotypes in two Japanese populations, inhabitants around Tokyo and in Sakishima Islands. The number of EDAR 1540C alleles in an individual was strongly correlated with the tooth-shoveling grade (p = 7.7 × 10?10). The effect of the allele was additive and explained 18.9% of the total variance in the shoveling grade, which corresponds to about one-fourth of the heritability of the trait reported previously. For data reduction of individual-level metric data, we applied a principal-component analysis, which yielded PC1-4, corresponding to four patterns of tooth size; this result implies that multiple factors are involved in dental morphology. The 1540C allele also significantly affected PC1 (p = 4.9 × 10?3), which denotes overall tooth size, and PC2 (p = 2.6 × 10?3), which denotes the ratio of mesiodistal diameter to buccolingual diameter.

Kimura, Ryosuke; Yamaguchi, Tetsutaro; Takeda, Mayako; Kondo, Osamu; Toma, Takashi; Haneji, Kuniaki; Hanihara, Tsunehiko; Matsukusa, Hirotaka; Kawamura, Shoji; Maki, Koutaro; Osawa, Motoki; Ishida, Hajime; Oota, Hiroki

2009-01-01

323

Central nucleus-nucleus collisions at relativistic energies with a new method based on Random Matrix Theory  

NASA Astrophysics Data System (ADS)

Using the method based on Random Matrix Theory (RMT), the results for the nearest-neighbor distributions obtained from the experimental data on 12C-C collisions at 4.2 AGeV/c have been discussed and compared with the simulated data on 12C-C collisions at 4.2 AGeV/c produced with the aid of the Dubna Cascade Model. The results show that the correlation of secondary particles decreases with an increasing number of charged particles Nch. These observed changes in the nearest-neighbor distributions of charged particles could be associated with the centrality variation of the collisions.

Wazir, Z.; G. Nazmitdinov, R.; I. Shahaliev, E.; K. Suleymanov, M.

2010-08-01

324

Palaeoclimates in central and south America since 18,000 BP based on pollen and lake-level records  

NASA Astrophysics Data System (ADS)

The last 18 ka of palaeoclimates are discussed at 3 ka intervals based on palaeoenvironmental changes shown in pollen and lake level records from Central and South America. A total of 61 pollen records fulfill the requirements of continuity and chronology to be used in this synthesis: 8 records from tropical and subtropical lowlands in Central and South America; 7 records from the Central American Highlands; 26 records from the High Andes, north and south of the equator; 2 records from the southern subtropics; and 18 from the southern Andes and subantarctic islands. Palaeoclimatic interpretation of the pollen records is semiquantitative, based on bioclimatic parameters such as e.g. elevational temperature gradients or latitudinal precipitation gradients that can be related to vegetation zonation. Additional palaeoclimatic information is obtained from lake-level records, derived either from dated shorelines, or from the limnological history of lake sediment sections. Large-scale palaeoclimatic comparison of the proxy data records indicates that full- and late-glacial climates throughout Central and South America were cooler than today, by about 4 to 5°C, but that moisture patterns showed regional differentiation. Thus, in both the southern subtropics and high latitudes in southern Chile, conditions were substantially moister than today during full- and late-glacial times, whereas everywhere else conditions were far drier than today. In terms of palaeocirculation, this scenario can be interpreted as a poleward shift of the subtropical as well as the westerly circulation, a scenario that has been suggested by palaeoclimatic simulations from general circulation models (GCM). Another major palaeoclimatic aspect predicted by the GCM simulations is the suppressed early Holocene summer monsoon in the southern subtropics. Although proxy records are few from this zone, their palaeoenvironmental history during that time shows a period of aridity that would support the model. One of the most controversial aspects of South American palaeoclimates concerns the existence of a Younger Dryas equivalent, a cold period between 11 and 10 ka BP. Based on the existing data from South America, that show a great diversity of palaeoclimatic trends, the concept of an interval that is characterized by the same climatic signal as documented for the North Atlantic seems too simplistic. Moreover, at this point, only very few records have been analysed in sufficient detail to yield unambiguous climatic information for the interval in question. The principal outcome of this palaeoenvironmental and palaeoclimatic synthesis is the better understanding of the type and quality of data available at present, and the realization of regions and periods where much more and concerted effort is needed to address problems of intra- and interhemispheric palaeoclimatic correlations. Only then can questions concerning the mechanism of climatic change be tackled successfully.

Markgraf, Vera

325

Congenital malformations at birth in Central India: A rural medical college hospital based data  

PubMed Central

OBJECTIVE: To study the incidence of congenital anomalies and the associated risk factors in Department of Pediatrics at Mahatma Gandhi Institute of Medical Sciences, Sevagram, Wardha, a rural medical college hospital in central Maharashtra. MATERIALS AND METHODS: All the intramural deliveries between 1 January 2005 and 31 July 2007 comprised 9386 births and their 9324 mothers (62 mothers gave birth to twin babies). The newborns were examined and assessed systematically for the presence of congenital anomalies, system wise distribution of anomalies and risk factors attributable. RESULTS: Out of the total 9386 deliveries, 9194 were live births and 192 were stillbirths. The total number of babies with congenital malformations was 179 (1.91%). Out of the 9262 singleton births, 177 (1.05%) were malformed, whereas 2 of the 62 pairs of twins had birth defects. Nine of the 179 malformed babies (5.02%) were still born. Prematurity, increased maternal age, increasing birth order and low birth weight were found to have a higher risk of congenital anomalies. Cardiovascular malformations were most common in live births, followed by musculoskeletal and genitourinary anomalies. CONCLUSION: Congenital anomalies are a major cause of stillbirths and infant mortality. Evaluation of cardiovascular system to rule out congenital heart disease in high-risk mothers’ babies is the important factor to be considered.

Taksande, Amar; Vilhekar, Krishna; Chaturvedi, Pushpa; Jain, Manish

2010-01-01

326

Analysis of particulate matter concentrations in mazovia region, central poland, based on 2007-2010 data  

NASA Astrophysics Data System (ADS)

Measurement results of PM10 (particulate matter with diameters below 10 ?m) concentrations performed at four stations in central Poland (2007-2010) were analyzed in terms of levels and distributions of concentrations, the number of exceedances of the limit values and the causes of these exceedances. PM10 levels were similar at suburban and rural stations, except of one station located in the vicinity of a busy street. The median of PM10 concentration ranged from 26 ?g/m3 at suburban station to 44 ?g/m3 at Warsaw Kerb station. Seasonal variability analysis of PM10 concentration revealed an additional maximum beyond the usual autumn-winter one. This maximum occurred in April at all stations, and corresponded to seasonal wildfires activity and dust activation in Eastern Europe. Cluster analysis of back-trajectories revealed that PM10 concentrations depend on the direction of advection of the incoming air; the highest values are registered for air of regional and southern origins, while the lowest are for the airmasses coming from the north and northwest direction.

Pietruczuk, Aleksander; Jaros?awski, Janusz

2013-04-01

327

The Generation of Antiphase Oscillations and Synchrony by a Rebound-Based Vertebrate Central Pattern Generator  

PubMed Central

Many neural circuits are capable of generating multiple stereotyped outputs after different sensory inputs or neuromodulation. We have previously identified the central pattern generator (CPG) for Xenopus tadpole swimming that involves antiphase oscillations of activity between the left and right sides. Here we analyze the cellular basis for spontaneous left–right motor synchrony characterized by simultaneous bursting on both sides at twice the swimming frequency. Spontaneous synchrony bouts are rare in most tadpoles, and they instantly emerge from and switch back to swimming, most frequently within the first second after skin stimulation. Analyses show that only neurons that are active during swimming fire action potentials in synchrony, suggesting both output patterns derive from the same neural circuit. The firing of excitatory descending interneurons (dINs) leads that of other types of neurons in synchrony as it does in swimming. During synchrony, the time window between phasic excitation and inhibition is 7.9 ± 1 ms, shorter than that in swimming (41 ± 2.3 ms). The occasional, extra midcycle firing of dINs during swimming may initiate synchrony, and mismatches of timing in the left and right activity can switch synchrony back to swimming. Computer modeling supports these findings by showing that the same neural network, in which reciprocal inhibition mediates rebound firing, can generate both swimming and synchrony without circuit reconfiguration. Modeling also shows that lengthening the time window between phasic excitation and inhibition by increasing dIN synaptic/conduction delay can improve the stability of synchrony.

Merrison-Hort, Robert; Zhang, Hong-Yan; Borisyuk, Roman

2014-01-01

328

The generation of antiphase oscillations and synchrony by a rebound-based vertebrate central pattern generator.  

PubMed

Many neural circuits are capable of generating multiple stereotyped outputs after different sensory inputs or neuromodulation. We have previously identified the central pattern generator (CPG) for Xenopus tadpole swimming that involves antiphase oscillations of activity between the left and right sides. Here we analyze the cellular basis for spontaneous left-right motor synchrony characterized by simultaneous bursting on both sides at twice the swimming frequency. Spontaneous synchrony bouts are rare in most tadpoles, and they instantly emerge from and switch back to swimming, most frequently within the first second after skin stimulation. Analyses show that only neurons that are active during swimming fire action potentials in synchrony, suggesting both output patterns derive from the same neural circuit. The firing of excitatory descending interneurons (dINs) leads that of other types of neurons in synchrony as it does in swimming. During synchrony, the time window between phasic excitation and inhibition is 7.9 ± 1 ms, shorter than that in swimming (41 ± 2.3 ms). The occasional, extra midcycle firing of dINs during swimming may initiate synchrony, and mismatches of timing in the left and right activity can switch synchrony back to swimming. Computer modeling supports these findings by showing that the same neural network, in which reciprocal inhibition mediates rebound firing, can generate both swimming and synchrony without circuit reconfiguration. Modeling also shows that lengthening the time window between phasic excitation and inhibition by increasing dIN synaptic/conduction delay can improve the stability of synchrony. PMID:24760866

Li, Wen-Chang; Merrison-Hort, Robert; Zhang, Hong-Yan; Borisyuk, Roman

2014-04-23

329

Centralized Monitoring of the Microsoft Windows-based computers of the LHC Experiment Control Systems  

NASA Astrophysics Data System (ADS)

The control system of each of the four major Experiments at the CERN Large Hadron Collider (LHC) is distributed over up to 160 computers running either Linux or Microsoft Windows. A quick response to abnormal situations of the computer infrastructure is crucial to maximize the physics usage. For this reason, a tool was developed to supervise, identify errors and troubleshoot such a large system. Although the monitoring of the performance of the Linux computers and their processes was available since the first versions of the tool, it is only recently that the software package has been extended to provide similar functionality for the nodes running Microsoft Windows as this platform is the most commonly used in the LHC detector control systems. In this paper, the architecture and the functionality of the Windows Management Instrumentation (WMI) client developed to provide centralized monitoring of the nodes running different flavour of the Microsoft platform, as well as the interface to the SCADA software of the control systems are presented. The tool is currently being commissioned by the Experiments and it has already proven to be very efficient optimize the running systems and to detect misbehaving processes or nodes.

Varela Rodriguez, F.

2011-12-01

330

Growth and wear of incisor and cheek teeth in domestic rabbits (Oryctolagus cuniculus) fed diets of different abrasiveness.  

PubMed

Although patterns of tooth wear are crucial in palaeo-reconstructions, and dental wear abnormalities are important in veterinary medicine, experimental investigations on the relationship between diet abrasiveness and tooth wear are rare. Here, we investigated the effect of four different pelleted diets of increasing abrasiveness (due to both internal [phytoliths] and external abrasives [sand]) or whole grass hay fed for 2 weeks each in random order to 16 rabbits (Oryctolagus cuniculus) on incisor and premolar growth and wear, and incisor and cheek tooth length. Wear and tooth length differed between diets, with significant effects of both internal and external abrasives. While diet abrasiveness was linked to tooth length for all tooth positions, whole forage had an additional effect on upper incisor length only. Tooth growth was strongly related to tooth wear and differed correspondingly between diets and tooth positions. At 1.4-3.2?mm/week, the growth of cheek teeth measured in this study was higher than previously reported for rabbits. Dental abnormalities were most distinct on the diet with sand. This study demonstrates that concepts of constant tooth growth in rabbits requiring consistent wear are inappropriate, and that diet form (whole vs. pelleted) does not necessarily affect cheek teeth. Irrespective of the strong effect of external abrasives, internal abrasives have the potential to induce wear and hence exert selective pressure in evolution. Detailed differences in wear effects between tooth positions allow inferences about the mastication process. Elucidating feedback mechanisms that link growth to tooth-specific wear represents a promising area of future research. PMID:24700486

Müller, Jacqueline; Clauss, Marcus; Codron, Daryl; Schulz, Ellen; Hummel, Jürgen; Fortelius, Mikael; Kircher, Patrick; Hatt, Jean-Michel

2014-06-01

331

Comparison of Late Pleistocene and Modern Glacier Extents in Central Nepal Based on Digital Elevation Data and Satellite Imagery  

NASA Astrophysics Data System (ADS)

Late Pleistocene and modern ice extents in central Nepal are compared to estimate equilibrium line altitude (ELA) depressions. New techniques are used for determining the former extent of glaciers based on quantitative, objective geomorphic analyses of a ˜90-m resolution digital elevation model (DEM). For every link of the drainage network, valley form is classified as glacial or fluvial based on cross-valley shape and slope statistics. Down-valley transitions from glacial to fluvial form indicate the former limits of glaciation in each valley. Landsat Multispectral Scanner imagery for the same region is used to map current glacier extents. For both full-glacial and modern cases, ELAs are computed from the glacier limits using the DEM and a toe-to-headwall altitude ratio of 0.5. Computed ELA depressions range from 100-900 m with a modal value of ˜650 m and a mean of ˜500 m, values consistent with previously published estimates for the central Himalaya but markedly smaller than estimates for many other regions. We suggest that this reflects reduced precipitation, rather than a small temperature depression, consistent with other evidence for a weaker monsoon under full-glacial conditions.

Duncan, Christopher C.; Klein, Andrew J.; Masek, Jeffrey G.; Isacks, Bryan L.

1998-05-01

332

PHYSICS AND CONTROL OF ELMING H-MODE NEGATIVE CENTRAL SHEAR ADVANCED TOKAMAK SCENARIO BASED ON EXPERIMENTAL PROFILES FOR ITER  

SciTech Connect

A271 PHYSICS AND CONTROL OF ELMING H-MODE NEGATIVE CENTRAL SHEAR ADVANCED TOKAMAK SCENARIO BASED ON EXPERIMENTAL PROFILES FOR ITER. Key DIII-D AT experimental and modeling results are applied to examine the physics and control issues for ITER to operate in a negative central shear (NCS) AT scenario. The effects of a finite edge pressure pedestal and current density are included based on the DIII-D experimental profiles. Ideal and resistive stability analyses indicate that feedback control of resistive wall modes by rotational drive or flux conserving intelligent coils is crucial for these AT configurations to operate at attractive {beta}{sub N} values in the range of 3.0-3.5. Vertical stability and halo current analyses show that reliable disruption mitigation is essential and mitigation control using an impurity gas can significantly reduce the local mechanical stress to an acceptable level. Core transport and turbulence analyses demonstrate that control of the rotational shear profile is essential to maintain the good confinement necessary for high {beta}. Consideration of edge stability and core transport suggests that a sufficiently wide pedestal is necessary for the projected fusion performance. Heat flux analyses indicate that with core-only radiation enhancement the outboard peak divertor heat load is near the design limit of 10 MW/m{sup 2}

LAO,LL; CHAN,VS; EVANS,TE; HUMPHREYS,DA; LEUER,JA; MAHDAVI,MA; PETRIE,TW; SNYDER,PB; STJOHN,HE; STAEBLER,GM; STAMBAUGH,RD; TAYLOR,TS; TURNBULL,AD; WEST,WP; BRENNAN,DP

2002-11-01

333

Immediate esthetic treatment of an avulsed/replanted permanent incisor with extensive root resorption: a case report.  

PubMed

This article describes the treatment of a 10 year-old patient with complete root resorption of the maxillary permanent incisor following avulsion and replantation 4 years earlier. The remaining natural crown was used to immediately solve the esthetic problem created by its extraction. The crown was attached with an orthodontic wire and composite resin to adjacent teeth. This temporary treatment does not elicit any damage to adjacent teeth, and can be easily removed. Therefore, it does not affect any plans that might be considered in the future as the permanent treatment. PMID:8619974

Holan, G; Botzer, E

1996-01-01

334

Glycosiderophores: synthesis of tris-hydroxamate siderophores based on a galactose or glycero central scaffold, Fe(III) complexation studies.  

PubMed

A series of five new hexadentate tris-hydroxamate ligands based on a d-galactose or a glycerol scaffold have been synthesized. Protonation and ferric complex formation constants have been determined from solution studies by potentiometric and spectrophotometric titrations. All ligands form 1:1 Fe:L complexes. The calculated pFe values at pH 7.4 span over the range 19.2-23.0 depending on the scaffold and on the length of the spacers between hydroxamate and central scaffold and on the N-methyl substitution. This new kind of artificial siderophores based on a glycoscaffold is of interest as it opens up an easy way to modulate the pFe. PMID:22551986

Neff, Christelle; Bellot, François; Waern, Jenny-Birgitta; Lambert, François; Brandel, Jérémy; Serratrice, Guy; Gaboriau, François; Policar, Clotilde

2012-07-01

335

Magmatic occurrences in the Central Arava (southern Israel) based on Geology and Magnetometry  

NASA Astrophysics Data System (ADS)

The Eshet Ridge is located in the Central Arava near Wadi Paran. Geological data were collected using ground magnetic surveys and petrophysical measurements (magnetic susceptibility and density). The goal was to reveal the structure and nature of a concealed magmatic body under the ridge. Integrated gravity and magnetic interpretation together with seismic reflection data (including 2¾ modeling) indicated the presence of a deep-seated basic magmatic intrusion. Occurrence of Fe-mineralized rocks along the ridge supports subsurface data. The magmatic body was intruded in the hard Turonian rocks of the Eshet Ridge. Basic magmatic exposures dating from the Early Miocene were evident along Wadi Ashosh (in the eastern Negev) and its margins 18 km. to the north of the ridge. A new outcrop of basic magmatic intrusion was found southwest of the Tzukim settlement. Magnetic measurements indicated a similarity between their magnetic pattern and the Ashosh basic magmatics, which were dated to 20.4 ± 0.7 Ma. Volcanoclastic tuff pebbles (magnetic susceptibility of around 2-7 * 10-3 SI) surrounded by conglomerate were discovered at two sites in Wadi Demma and Wadi Menuha (streams that drain near the Eshet Ridge and 2 km south of it, respectively). The conglomerates contained mostly limestone, chalk and chert fragments; not more than 5% of which were volcanic pebbles. Two pebbles were dated to 24.4 ± 0.7and 21.5 ± 0.5 Ma. The magmatic outcrops in Wadi Ashosh, the magmatic dyke near Tzukim and the volcanic purple and black pebbles near Wadi Menuha were all dated to the very Late Oligocene-Early Miocene. The magmatic body identified in this study under the Eshet Ridge was termed the Eshet Intrusion and is connected to, and even the source of, all these phenomena.

Hanan, Ginat; Michael, Rybakov; Boris, Shirman; Michael, Lazar

2014-05-01

336

Security of Business to Business and Business to Customer Software Applications based on the Central Dogma of Molecular Biology (CDMB) and evolutionary models  

Microsoft Academic Search

The development, implementation and testing for Security of Business to Business and Business to Customer Software Applications System is based on the Central Dogma of Molecular Biology (CDMB), where we derive DNA Cryptographic Keys based on evolutionary models as public-key algorithms are based on mathematical functions rather than on substitution and permutation involving the use of two separate keys, in

Tatiana Hodorogea; Ionas Szilard Otto

2011-01-01

337

A GPS-based three-dimensional lightning mapping system: Initial observations in central New Mexico  

Microsoft Academic Search

A GPS-based system has been developed that accurately locates the sources of VHF radiation from lightning discharges in three spatial dimensions and time. The observations are found to reflect the basic charge structure of electrified storms. Observations have also been obtained of a distinct type of energetic discharge referred to as positive bipolar breakdown, recently identified as the source of

W. Rison; R. J. Thomas; P. R. Krehbiel; T. Hamlin; J. Harlin

1999-01-01

338

Site-based Management: Is It Still Central to the School Reform Movement?  

ERIC Educational Resources Information Center

This research summary says school-based management increases political activity in schools, but is time-consuming; many teachers evade SBM; less actively participating parents risk co-option by educators; and schools will not commit necessary resources. Academic achievement is not necessarily improved, and organizational implementation obstacles…

Brown, Frank

2001-01-01

339

Fingerprint Classification Based on Improved Singular Points Detection and Central Symmetrical Axis  

Microsoft Academic Search

Effective fingerprint classification not only can provide an important index mechanism for large fingerprint database, but also can improve the efficiency and performance of AFIS. At present, because of traditional Poincare method detection more false singular points and weaker anti-noise problem, this paper presents a fingerprint classification method based on continuously directional image and symmetrical axis. Compared with traditional algorithms,

Wang Feng; Chen Yun; Wang Hao; Wang Xiu-you

2009-01-01

340

The beaver Anchitheriomys from the Miocene of Central Europe  

SciTech Connect

New finds of teeth and mandibles of Anchitheriomys from the Hambach opencast lignite mine in Northwest Germany and the first detailed descriptions of other mandibles from South Germany and Switzerland allow a review of the Central European specimens of this rare beaver genus. The metric variation of cheek teeth and especially the great differences in dimensions of incisors can be much better assessed. The observed range in size can be attributed to ontogenetic changes, and all material is assigned to Anchitheriomys suevicus. Stratigraphically, this species is restricted to the early middle Miocene, European Mammalian Neogene biozones MN 5-6.

Stefen, C.; Mors, T. [Museum Tierkunde, Dresden (Germany)

2008-09-15

341

Provenance of the Subinal Formation, Central Guatemala, Based on Point-Counting of Pebbles in Conglomerates  

NASA Astrophysics Data System (ADS)

The continental Subinal Formation of Central Guatemala is composed of red conglomerates and sandstones that outcrop in the Motagua valley between the San Agustín and Cabañas fault, and in the southeastern corner of Guatemala. Stratigraphic position implies a post-Cretaceous depositional age, which has not been accurately established. Point counts of pebbles in conglomerates were performed in localities distributed along the Motagua valley from Granados to Los Amates, and in the Jocotán-Esquipulas area near the border with Honduras. Pebble types contained in conglomerates in the Motagua area are very diverse, and include sandstones, limestones, chert, milky quartz, phyllite, marble, chlorite schist, quartz-muscovite schist, amphibolite, eclogite, gneiss, granite, gabbro/diorite, volcanic rocks, and abundant serpentinite. Schist and gneiss resembles rocks of the Chuacús complex. Serpentinite, gabbro, amphibolite, and eclogite clasts are similar to oceanic lithosphere from the Motagua suture. Abundant white mica in interbedded sandstones is ubiquitous, suggesting derivation from the mica-rich Chuacús complex. Unfoliated granites and volcanic clasts were probably derived from the northern edge of the Chortis block or an unknown terrane, as no unmetamorphosed igneous rocks are known from the southern edge of the Maya block. The relative abundance of some clast groups correlates with the rock units exposed immediately adjacent to the north across the San Agustín fault. Serpentinite in conglomerate is most abundant near Juan de Paz; eclogite, amphibolite and gneiss are most abundant in the Granados area; and white mica is most abundant where Chuacús complex schists are most pelitic. This suggests that the Cabañas fault accommodated most of the strike-slip movement of the Motagua fault system. In contrast, conglomerates in southeastern Guatemala are more homogeneous, containing chiefly clasts of volcanic origin, with minor limestone, graphitic phyllite, chert, and milky quartz. Pebbles were probably derived from the underlying Padre Miguel volcanics that occur within the Chortis block, not from rock units in the Motagua suture zone. Pebbles contained in red beds in the Motagua valley were derived from rock units of the Motagua suture and the southern margin of the Maya block, but provenance from rock of the Chortis block is not clear. These findings suggest that red-bed-bearing basins in the Motagua valley and in the southeast of Guatemala were not connected, and may have formed at disparate times.

Gutierrez, A.; Martens, U.

2007-05-01

342

Cortical, callosal, and thalamic connections from primary somatosensory cortex in the naked mole-rat (Heterocephalus glaber), with special emphasis on the connectivity of the incisor representation.  

PubMed

We investigated the distribution of cortical, callosal, and thalamic connections from the primary somatosensory area (S1) in naked mole-rats, concentrating on lower incisor and forelimb representations. A neuronal tracer (WGA-HRP) was injected into the center of each respective representation under guidance from microelectrode recordings of neuronal activity. The locations of cells and terminals were determined by aligning plots of labeled cells with flattened cortical sections reacted for cytochrome oxidase. The S1 lower incisor area was found to have locally confined intrahemispheric connections and longer connections to a small cluster of cells in the presumptive secondary somatosensory (S2) and parietal ventral (PV) incisor fields. The S1 incisor area also had sparse connections with anterior cortex, in presumptive primary motor cortex. Homotopic callosal projections were identified between the S1 lower incisor areas in each hemisphere. Thalamocortical connections related to the incisor were confined to ventromedial portions of the ventral posterior medial subnucleus (VPM) and posterior medial nucleus (Po). Injections into the S1 forelimb area revealed reciprocal intrahemispheric connections to S2 and PV, to two areas in frontal cortex, and to two areas posterior to S1 that appear homologous to posterior lateral area and posterior medial area in rats. The S1 forelimb representation also had callosal projections to the contralateral S1 limb area and to contralateral S2 and PV. Thalamic distribution of label from forelimb injections included ventral portions of the ventral posterior lateral subnucleus (VPL), dorsolateral Po, the ventral lateral nucleus, and the ventral medial nucleus and neighboring intralaminar nuclei. PMID:16652365

Henry, Erin C; Catania, Kenneth C

2006-06-01

343

New neonatal classification of unilateral cleft lip and palate-part 1: to predict primary lateral incisor agenesis and inherent tissue hypoplasia.  

PubMed

Objectives : To bring a neonatal classification system of unilateral cleft lip and palate (UCLP) and to correlate this classification with the distribution of the primary lateral incisor. Design : Retrospective with longitudinal follow-up. Setting : Tertiary. Patients : One hundred twenty-one patients with treated UCLP. Thirteen plaster casts were used as controls. Main Outcome Measures : The UCLP patients were classified anatomically into four categories: class 1 corresponds to a maxillary arch with a narrow alveolar cleft, class 2 corresponds to a balanced form, class 3 corresponds to a wide cleft and short maxilla, and class 4 corresponds to a wide cleft and long maxilla. Clinical validity was evaluated with a concordance analysis (intra- and interexaminer). This anatomical classification was also corroborated with an automatic classification determined by morphometric parameters measured on neonatal maxillary plaster casts. The class was finally correlated with the distribution of the primary lateral incisor. Results : Clinical classification of UCLP found 12 cases of class 1 (9.9%), 36 cases of class 2 (29.8%), 47 cases of class 3 (38.8%), and 26 cases of class 4 (21.5%). The clinical classification was validated with a good intra- and interexaminer concordance analysis (? > .6). The automatic classification was close to the clinical classification in 84%. The correlation was ideal in class 1 (100%), almost perfect in class 4 (92%), but lower for class 2 (74%) and class 3 (70%). The primary lateral incisor was usually duplicated in class 1, whereas class 2 and class 4 were correlated with a primary lateral incisor located on the lateral palatal segment. Class 3 was associated with an agenesis of the primary lateral incisor (P < .001). Conclusions : UCLP can be classified into four different classes at birth, which can all give information about the inherent tissue hypoplasia and the distribution of the primary lateral incisor. PMID:23451717

Delestan, Christian; Montoya, Pedro; Doucet, Jean-Charles; Bigorre, Michèle; Baümler, Caroline; Herlin, Christian; Daures, Jean-Pierre; Captier, Guillaume

2014-07-01

344

Unifying model of carpal mechanics based on computationally derived isometric constraints and rules-based motion - the stable central column theory.  

PubMed

This study was part of a larger project to develop a (kinetic) theory of carpal motion based on computationally derived isometric constraints. Three-dimensional models were created from computed tomography scans of the wrists of ten normal subjects and carpal spatial relationships at physiological motion extremes were assessed. Specific points on the surface of the various carpal bones and the radius that remained isometric through range of movement were identified. Analysis of the isometric constraints and intercarpal motion suggests that the carpus functions as a stable central column (lunate-capitate-hamate-trapezoid-trapezium) with a supporting lateral column (scaphoid), which behaves as a 'two gear four bar linkage'. The triquetrum functions as an ulnar translation restraint, as well as controlling lunate flexion. The 'trapezoid'-shaped trapezoid places the trapezium anterior to the transverse plane of the radius and ulna, and thus rotates the principal axis of the central column to correspond to that used in the 'dart thrower's motion'. This study presents a forward kinematic analysis of the carpus that provides the basis for the development of a unifying kinetic theory of wrist motion based on isometric constraints and rules-based motion. PMID:24072199

Sandow, M J; Fisher, T J; Howard, C Q; Papas, S

2014-05-01

345

Task-Based Lessons: The Central Focus of a Mathematics Content Course for Future Elementary Teachers  

Microsoft Academic Search

A task-based lesson serves as the organizing principle for a university mathematics content course for future elementary teachers.\\u000a The course, which provides the first semester of a year-long sequence, covers the arithmetic of numbers. The daily classroom\\u000a activities follow a Japanese-style lesson plan and use tasks developed through a didactical phenomenological analysis. A situated\\u000a learning perspective frames an understanding of

Anne R. Teppo

346

Aetiologies of Central Nervous System Infection in Viet Nam: A Prospective Provincial Hospital-Based Descriptive Surveillance Study  

PubMed Central

Background Infectious diseases of the central nervous system (CNS) remain common and life-threatening, especially in developing countries. Knowledge of the aetiological agents responsible for these infections is essential to guide empiric therapy and develop a rational public health policy. To date most data has come from patients admitted to tertiary referral hospitals in Asia and there is limited aetiological data at the provincial hospital level where most patients are seen. Methods We conducted a prospective Provincial Hospital-based descriptive surveillance study in adults and children at thirteen hospitals in central and southern Viet Nam between August 2007– April 2010. The pathogens of CNS infection were confirmed in CSF and blood samples by using classical microbiology, molecular diagnostics and serology. Results We recruited 1241 patients with clinically suspected infection of the CNS. An aetiological agent was identified in 640/1241 (52%) of the patients. The most common pathogens were Streptococcus suis serotype 2 in patients older than 14 years of age (147/617, 24%) and Japanese encephalitis virus in patients less than 14 years old (142/624, 23%). Mycobacterium tuberculosis was confirmed in 34/617 (6%) adult patients and 11/624 (2%) paediatric patients. The acute case fatality rate (CFR) during hospital admission was 73/617 (12%) in adults and to 42/624 (7%) in children. Conclusions Zoonotic bacterial and viral pathogens are the most common causes of CNS infection in adults and children in Viet Nam.

Ho Dang Trung, Nghia; Le Thi Phuong, Tu; Wolbers, Marcel; Nguyen Van Minh, Hoang; Nguyen Thanh, Vinh; Van, Minh Pham; Thieu, Nga Tran Vu; Le Van, Tan; Song, Diep To; Le Thi, Phuong; Thi Phuong, Thao Nguyen; Van, Cong Bui; Tang, Vu; Ngoc Anh, Tuan Hoang; Nguyen, Dong; Trung, Tien Phan; Thi Nam, Lien Nguyen; Kiem, Hao Tran; Thi Thanh, Tam Nguyen; Campbell, James; Caws, Maxine; Day, Jeremy; de Jong, Menno D.; Van Vinh, Chau Nguyen; Van Doorn, H. Rogier; Tinh, Hien Tran; Farrar, Jeremy; Schultsz, Constance

2012-01-01

347

Quantitative temperature reconstruction based on growth rate of annually-layered stalagmite: a case study from central China  

NASA Astrophysics Data System (ADS)

We used the annual growth rate of a stalagmite (XL21) collected from Xianglong Cave, central China, to quantitatively reconstruct regional terrestrial temperature changes over the last 95 years (1912-2006 AD). Based on a significant positive correlation between the growth rate and the observed temperature, a transfer function was designed, and the temperature from the previous September to May (P9-5) was reconstructed, with an explained variance of 43.5%. Our results show an increasing trend in temperature during the last century, and especially over the last 30 years. The temperature variability from central China recorded here bears a striking similarity to that in the Northern Hemisphere, and also to global trends. However, the cooling between the 1980s and the early 1990s seen in the stalagmite record, which interrupted the warming trend that began in the 1960s, is not observed in the mean conditions found in China, the Northern Hemisphere, neither globally. This methodology for reconstructing historical temperature from stalagmite growth rates overcomes the limitation of the short meteorological observation period and supports the potential of stalagmite lamina climatology.

Tan, Liangcheng; Yi, Liang; Cai, Yanjun; Shen, Chuan-Chou; Cheng, Hai; An, Zhisheng

2013-07-01

348

GIS-based seismic shaking slope vulnerability map of Sicily (Central Mediterranean)  

NASA Astrophysics Data System (ADS)

Earthquakes often represent very dangerouses natural events in terms of human life and economic losses and their damage effects are amplified by the synchronous occurrence of seismically-induced ground-shaking failures in wide regions around the seismogenic source. In fact, the shaking associated with big earthquakes triggers extensive landsliding, sometimes at distances of more than 100 km from the epicenter. The active tectonics and the geomorphic/morphodinamic pattern of the regions affected by earthquakes contribute to the slopes instability tendency. In fact, earthquake-induced groun-motion loading determines inertial forces activation within slopes that, combined with the intrinsic pre-existing static forces, reduces the slope stability towards its failure. Basically, under zero-shear stress reversals conditions, a catastrophic failure will take place if the earthquake-induced shear displacement exceeds the critical level of undrained shear strength to a value equal to the gravitational shear stress. However, seismic stability analyses carried out for various infinite slopes by using the existing Newmark-like methods reveal that estimated permanent displacements smaller than the critical value should also be regarded as dangerous for the post-earthquake slope safety, in terms of human activities use. Earthquake-induced (often high-speed) landslides are among the most destructive phenomena related to slopes failure during earthquakes. In fact, damage from earthquake-induced landslides (and other ground-failures), sometimes exceeds the buildings/infrastructures damage directly related to ground-shaking for fault breaking. For this matter, several hearthquakes-related slope failures methods have been developed, for the evaluation of the combined hazard types represented by seismically ground-motion landslides. The methodologies of analysis of the engineering seismic risk related to the slopes instability processes is often achieved through the evaluation of the permanent displacement potentially induced by an seismic scenario. Such methodologies found on the consideration that the conditions of seismic stability and the post-seismic functionality of engineering structures are tightly related to the entity of the permanent deformations that an earthquake can induce. Regarding the existing simplified procedures among slope stability models, Newmark's model is often used to derive indications about slope instabilities due to earthquakes. In this way, we have evaluated the seismically-induced landslides hazard in Sicily (Central Mediterranean) using the Newmark-like model. In order to determine the map distribution of the seismic ground-acceleration from an earthquake scenario, the attenuation-law of Sabetta & Pugliese has been used, analyzing some seismic recordings occurred in Italy. Also, by evaluating permanent displacements, the correlation of Ambraseys & Menu has been assumed. The seismic shaking slope vulnerability map of Sicily has been carried out using GIS application, also considering max seismic ground-acceleration peak distribution (in terms of exceedance probability for fixed time), slope acclivity, cohesion/angle of internal friction of outcropping rocks, allowing the zoning of the unstable slopes under seismic forces.

Nigro, Fabrizio; Arisco, Giuseppe; Perricone, Marcella; Renda, Pietro; Favara, Rocco

2010-05-01

349

A conodont-based standard reference section in central Nevada for the lower Middle Ordovician Whiterockian Series  

USGS Publications Warehouse

Ranges of conodonts in stratigraphic sections at five localities in the Monitor and Antelope ranges of central Nevada are used graphically to assemble a standard reference section for the lower Middle Ordovician Whiterockian Series. The base of the series is officially 0.3 m above the base of the Antelope Valley Limestone in the stratotype in Whiterock Canyon (Monitor Range). The top is the level at which Baltoniodus gerdae makes a brief appearance in an exposure of the Copenhagen Formation on the flanks of Hill 8308 in the western Antelope Range. Graphic compilation of the sections considered in this report also indicates that a level correlative with the base of the Whiterockian Series in the stratotype section is 66 m above the base of the Antelope Valley Limestone in its de facto type section on Martin Ridge in the eastern part of the Monitor Range. Ranges, diversity, and the composition of the conodont faunas differ markedly in lithofacies adjacent to the basal boundary of the series; hence we are unable to identify a single conodont species, in a credible developmental sequence, to serve as biological marker of that boundary.

Sweet, W. C.; Ethington, R. L.; Harris, A. G.

2005-01-01

350

Prosthodontic considerations in the implant-supported all-ceramic restoration of congenitally missing maxillary lateral incisor: a clinical report.  

PubMed

The congenitally missing maxillary lateral incisor is the most common agenesis in the anterior region. There are several treatment options for this anomaly, which causes severe deficiencies: orthodontic space closure, tooth-supported restoration, or single-tooth implant. Each of these solutions has a high degree of success if used in the correct situation. An implant-supported restoration with an interdisciplinary approach provides a predictable outcome. This article describes the treatment of a patient with agenesis of the maxillary left lateral incisor. After orthodontic space management, it was decided to restore the tooth with an all-ceramic crown cemented on a zirconia custom abutment, which fractured after only 6 weeks of service. Fractographic analysis revealed that the failure was due to over-reduction of the buccal wall to correct the labial emergence of the implant. Zirconia abutments should be designed with even wall thicknesses of at least 0.8 mm to avoid areas that may compromise functional success. PMID:24118630

Martínez-Rus, Francisco; Rivera, Begoña; Ozcan, Mutlu; Pradíes, Guillermo

2014-04-01

351

Bmi1 represses Ink4a/Arf and Hox genes to regulate stem cells in the rodent incisor  

PubMed Central

The polycomb group gene Bmi1 is required for maintenance of adult stem cells in many organs1, 2. Inactivation of Bmi1 leads to impaired stem cell self-renewal due to deregulated gene expression. One critical target of BMI1 is Ink4a/Arf, which encodes the cell cycle inhibitors p16ink4a and p19Arf3. However, deletion of Ink4a/Arf only partially rescues Bmi1 null phenotypes4, indicating that other important targets of BMI1 exist. Here, using the continuously-growing mouse incisor as a model system, we report that Bmi1 is expressed by incisor stem cells and that deletion of Bmi1 resulted in fewer stem cells, perturbed gene expression, and defective enamel production. Transcriptional profiling revealed that Hox expression is normally repressed by BMI1 in the adult, and functional assays demonstrated that BMI1-mediated repression of Hox genes preserves the undifferentiated state of stem cells. As Hox gene upregulation has also been reported in other systems when Bmi1 is inactivated1, 2, 5–7, our findings point to a general mechanism whereby BMI1-mediated repression of Hox genes is required for the maintenance of adult stem cells and for prevention of inappropriate differentiation.

Biehs, Brian; Hu, Jimmy Kuang-Hsien; Strauli, Nicolas B.; Sangiorgi, Eugenio; Jung, Heekyung; Heber, Ralf-Peter; Ho, Sunita; Goodwin, Alice F.; Dasen, Jeremy S.; Capecchi, Mario R.; Klein, Ophir D.

2013-01-01

352

An Immature Type II Dens Invaginatus in a Mandibular Lateral Incisor with Talon's Cusp: A Clinical Dilemma to Confront.  

PubMed

Dens invaginatus (DI) is a malformation of teeth probably resulting from an infolding of the dental papilla during tooth development. DI is classified as type I, II, and III by Oehlers depending on the severity of malformation. The maxillary lateral incisor is the most commonly affected tooth. Structural defects do exist in the depth of the invagination pits, and as a consequence, the early development of caries and the subsequent necrosis of the dental pulp, as well as abscess and cyst formation are clinical implications associated with DI. Occasionally, we can see more than one developmental anomaly occurring in a single tooth. In such cases it becomes important to identify the anomalies and initiate a proper treatment plan for good prognosis. In this paper, an unusual case of DI which clinically presented as a huge talons cusp affecting a mandibular lateral incisor tooth is described. This case report illustrates grinding of the talons cusp followed by nonsurgical endodontic management of dens invaginatus type II with an immature apex and periapical lesions, in which Mineral Trioxide Aggregate (MTA) shows a complete periapical healing with bone formation at the site of the lesions. PMID:24660071

Gangwar, Anshul; Singal, Deepa; Giri, K Y; Agarwal, Anshita; Keerthi, S Sruthi

2014-01-01

353

Characterization of Dental Epithelial Stem Cells from the Mouse Incisor with Two-Dimensional and Three-Dimensional Platforms  

PubMed Central

Dental epithelial stem cells (DESCs) drive continuous growth in the adult mouse incisors. To date, a robust system for the primary culture of these cells has not been reported, and little is known about the basic molecular architecture of these cells or the minimal extracellular scaffolding that is necessary to maintain the epithelial stem cell population in an undifferentiated state. We report a method of isolating DESCs from the cervical loop of the mouse mandibular incisor. Cells were viable in a two-dimensional culture system and did not demonstrate preferential proliferation when grown on top of various substrates. Characterization of these cells indicated that E-cadherin, integrin alpha-6, and integrin beta-4 mark the DESCs both in vivo and in vitro. We also grew these cells in a three-dimensional microenvironment and obtained spheres with an epithelial morphology and expression patterns. Insights into the mechanisms of stem cell maintenance in vitro will help lay the groundwork for the successful generation of bioengineered teeth from adult DESCs.

Chavez, Miquella G.; Yu, Wenli; Biehs, Brian; Harada, Hidemitsu; Snead, Malcolm L.; Lee, Janice S.; Desai, Tejal A.

2013-01-01

354

Mineral trioxide aggregate apical plug method for the treatment of nonvital immature permanent maxillary incisors: Three case reports  

PubMed Central

Treatment of nonvital immature permanent teeth with calcium-hydroxide is associated with some difficulties such as weakened tooth fracture, root canal reinfection and long treatment time. Mineral trioxide aggregate (MTA) apical plug method is an alternative treatment option for open apices, and has gained popularity in the recent times. In this case report, we have attempted to present successful treatment of three maxillary incisors with open apices and periapical lesions with MTA. After preparing the access cavity, the working length was determined. The root canals were irrigated with 2.5% Sodium hypochlorite (NaOCl) and disinfected with calcium-hydroxide for two weeks. MTA was then placed in the apical 3 millimeters of the root canal. The remaining part of the root canal was filled with gutta-percha and the coronal restoration was finished with composite resin. After six months the radiographic examination showed a decrease of periapical lesions. At a 1-year and 18-months follow up, radiological and clinical successful healing of the incisor teeth was seen. MTA seems as an effective material for the apical plug method for the treatment of nonvital immature permanent teeth with open apices.

Gunes, Betul; Aydinbelge, Hale Ari

2012-01-01

355

Temperature changes on the root surfaces of mandibular incisors after an 810-nm high-intensity intracanal diode laser irradiation  

NASA Astrophysics Data System (ADS)

Temperature changes caused by laser irradiation can promote damage to the surrounding dental tissues. In this study, we evaluated the temperature changes of recently extracted human mandibular incisors during intracanal irradiation with an 810-nm diode laser at different settings. Fifty mandibular incisors were enlarged up to an apical size of ISO No. 40 file. After the final rinse with 17% ethylenediaminetetraacetic acid, 0.2% lauryl sodium sulfate biologic detergent, and sterile water, samples were irradiated with circular movements from apex to crown through five different settings of output power (1.5, 2.0, 2.5, 3.0, and 3.5 W) in continuous mode. The temperature changes were measured on both sides of the apical and middle root thirds using two thermopar devices. A temperature increase of 7 °C was considered acceptable as a safe threshold when applying the diode laser. Results: The results showed that only 3.5-W output power increased the outer surface temperature above the critical value. Conclusion: The recommended output power can be stipulated as equal to or less than 3 W to avoid overheating during diode laser irradiation on thin dentin walls.

da Fonseca Alvarez, Andrea; Moura-Netto, Cacio; Daliberto Frugoli, Alexandre; Fernando, Casemiro; Correa Aranha, Ana Cecilia; Davidowicz, Harry

2012-01-01

356

Effect of post type and restorative techniques on the strain and fracture resistance of flared incisor roots.  

PubMed

Restoring flared endodontically treated teeth continues to be a challenge for clinicians. This study evaluated the effect of post types and restorative techniques on the strain, fracture resistance, and fracture mode of incisors with weakened roots. One hundred five endodontically treated bovine incisors roots (15 mm) were divided into 7 groups (n=15). The two control groups were (C) intact roots restored with Cpc (cast posts and core) or Gfp (glass fiber posts). The five experimental groups were (F) flared roots restored with GfpAp (Gfp associated with accessory glass fiber posts), GfpRc (anatomic Gfp, relined with composite resin), and GfpRcAp (anatomized Gfp with resin and accessory glass fiber posts). All teeth were restored with metal crowns. Mechanical fatigue was performed with 3x10(5)/50 N. Specimens were loaded at 45º, and the strain values (?S) were obtained on root buccal and proximal surfaces. Following that, the fracture resistance (N) was measured. One-way ANOVA and Tukey's HSD tests (?=0.05) were applied, and failure mode was checked. No significant difference in strain values among the groups was found. Cpc presented lower fracture resistance and more catastrophic failures in flared roots. Gfp associated with composite resin or accessory glass fiber posts seems to be an effective method to improve the biomechanical behavior of flared roots. PMID:21915521

Silva, Gisele Rodrigues da; Santos-Filho, Paulo César de Freitas; Simamoto-Júnior, Paulo Cézar; Martins, Luis Roberto Marcondes; Mota, Adérito Soares da; Soares, Carlos José

2011-01-01

357

An Immature Type II Dens Invaginatus in a Mandibular Lateral Incisor with Talon's Cusp: A Clinical Dilemma to Confront  

PubMed Central

Dens invaginatus (DI) is a malformation of teeth probably resulting from an infolding of the dental papilla during tooth development. DI is classified as type I, II, and III by Oehlers depending on the severity of malformation. The maxillary lateral incisor is the most commonly affected tooth. Structural defects do exist in the depth of the invagination pits, and as a consequence, the early development of caries and the subsequent necrosis of the dental pulp, as well as abscess and cyst formation are clinical implications associated with DI. Occasionally, we can see more than one developmental anomaly occurring in a single tooth. In such cases it becomes important to identify the anomalies and initiate a proper treatment plan for good prognosis. In this paper, an unusual case of DI which clinically presented as a huge talons cusp affecting a mandibular lateral incisor tooth is described. This case report illustrates grinding of the talons cusp followed by nonsurgical endodontic management of dens invaginatus type II with an immature apex and periapical lesions, in which Mineral Trioxide Aggregate (MTA) shows a complete periapical healing with bone formation at the site of the lesions.

Singal, Deepa; Giri, K. Y.; Keerthi, S. Sruthi

2014-01-01

358

Molar-incisor hypomineralization and oral hygiene in 10- to-12-yr-old Swedish children born preterm.  

PubMed

Although preterm birth is associated with an increased risk of medical problems and impairments, there is limited knowledge of how this affects oral health. It was hypothesized that when 10-12 yr of age, children who were preterm at birth would present with a higher prevalence of molar-incisor hypomineralization (MIH), more dental plaque, and a higher degree of gingival inflammation than full-term control children. Eighty-two preterm children, born between 24 and 32 wk of gestation, and 82 control children, born between 37 and 43 wk of gestation, were clinically examined for developmental defects in enamel, MIH, dental plaque, and gingival health. In addition, behaviour management problems were evaluated. Information on any aetiological factors with a potential influence on MIH and oral health was collected via questionnaires. Molar-incisor hypomineralization was more common in preterm children than in controls (38% vs. 16%), as were enamel developmental defects (69.5% vs. 51%). Low gestational age and low birth weight increased the risk of MIH. Preterm children had more plaque, a higher degree of gingival inflammation, and more behaviour-management problems than controls. In conclusion, oral health problems were more common in preterm children than in control children. PMID:21244509

Brogårdh-Roth, Susanne; Matsson, Lars; Klingberg, Gunilla

2011-02-01

359

Object based change detection of Central Asian Tugai vegetation with very high spatial resolution satellite imagery  

NASA Astrophysics Data System (ADS)

Ecological restoration of degraded riparian Tugai forests in north-western China is a key driver to combat desertification in this region. Recent restoration efforts attempt to recover the forest along with its most dominant tree species, Populus euphratica. The present research observed the response of natural vegetation using an object based change detection method on QuickBird (2005) and WorldView2 (2011) data. We applied the region growing approach to derived Normalized Difference Vegetation Index (NDVI) values in order to identify single P. euphratica trees, delineate tree crown areas and quantify crown diameter changes. Results were compared to 59 reference trees. The findings confirmed a positive tree crown growth and suggest a crown diameter increase of 1.14 m, on average. On a single tree basis, tree crown diameters of larger crowns were generally underestimated. Small crowns were slightly underestimated in QuickBird and overestimated in Worldview2 images. The results of the automated tree crown delineation show a moderate relation to field reference data with R20052: 0.36 and R20112: 0.48. The object based image analysis (OBIA) method proved to be applicable in sparse riparian Tugai forests and showed great suitability to evaluate ecological restoration efforts in an endangered ecosystem.

Gärtner, Philipp; Förster, Michael; Kurban, Alishir; Kleinschmit, Birgit

2014-09-01

360

Simulation of a rubber plantation productivity in central Cambodia using the individual-based dynamic vegetation model SEIB-DGVM  

NASA Astrophysics Data System (ADS)

To provide a useful tool for building strategy of forest plantation management, we developed the Spatially Explicit Individual-Based (SEIB) Dynamic Global Vegetation Model (DGVM) applicable to simulate productivity of tree plantations (SEIB-PP). Rubber (Hevea brasiliensis Müll. Arg.) plantations, which are rapidly expanding into both climatically optimal and sub-optimal environments throughout mainland Southeast Asia, potentially change the partitioning of water, energy, and carbon at multiple scales, compared with traditional land covers that are being replaced. Describing both primary and latex productivities in rubber plantations via SEIB-PP is, therefore, important to understanding the climatic impacts on productive processes. Model results are compared with measurements collected at a field site in central Cambodia, and here, we show some examples of projections: the rubber plantation production under future climate change conditions.

Kumagai, T.; SATO, H.; Shinjiro, Ph. D., F.

2013-12-01

361

Central DXA utilization shifts from office-based to hospital-based settings among medicare beneficiaries in the wake of reimbursement changes.  

PubMed

In the United States, Medicare gradually reduced payments for central dual-energy X-ray absorptiometry (DXA) performed at physician offices (or other nonhospital settings) from an average of $139 in 2006 to about $82 in 2007 and 2008 and $72 in 2009. Reimbursement for hospital outpatient DXA service was unchanged. We investigated the utilization of hip and spine (central) DXA in the Medicare population before and after the reduction. We identified individuals from the national 5% random sample of Medicare beneficiaries who were ?65 years of age and enrolled in Medicare Parts A and B but not in a Medicare Advantage plan from 2002 through 2009. For each calendar year, we calculated the proportion of beneficiaries who submitted claims for DXA, the proportions of DXAs performed in hospitals and in physician offices and the number of physician office-based practices that discontinued or started to provide DXA services. From 2002 to 2006, the proportion of beneficiaries who had at least one central DXA increased from 7.9% to 9.6% at an annual increase of 0.4% and from 2006 to 2009, the annual increase dropped to 0.1%. The number of DXAs performed in physician offices dropped from 1,643,720 (69% of 2,363,500 total DXAs) in 2006 to 1,534,240 (66% of 2,338,240) in 2009. This decline was offset by an increase in the number of DXAs performed in hospitals, which increased from 719,780 (31%) in 2006 to 804,000 (34%) in 2009. Among physician office-based practices, more practices initiated than discontinued DXA service each year from 2002 to 2006. However, the trend was reversed since 2007 such that in 2009, 1876 practices discontinued and only 1394 initiated DXA service. The reduction in DXA reimbursement was associated with a decrease in the number of DXAs performed in physician offices and fewer physician offices that provided DXA services. PMID:22190195

Zhang, Jie; Delzell, Elizabeth; Zhao, Hong; Laster, Andrew J; Saag, Kenneth G; Kilgore, Meredith L; Morrisey, Michael A; Wright, Nicole C; Yun, Huifeng; Curtis, Jeffrey R

2012-04-01

362

Energy-based Location and Wavefield Polarization Analysis of Tectonic Tremors in Central Mexico  

NASA Astrophysics Data System (ADS)

We have designed a location technique based on non-volcanic tremor (NVT) energy measurements and their spatial derivatives in the three ground motion components. By means of a source-scanning grid search and a large database of theoretical Green's functions (i.e. more than 45,000 functions from rake-variable horizontal point dislocations) accounting for both intrinsic attenuation and layered media, the algorithm looks for the hypocentral locations that minimize an error function between observed and synthetic spatial-energy distributions. However, since the energy has little information about the footprint of the source-radiation-pattern on the wavefield polarization we have introduced, into the location algorithm, a particle-motion polarization analysis. The analysis is based on the eigendecomposition of the covariance matrix determined from the three ground motion components, and provides the algorithm with much better control of both NVT location and source mechanism (i.e. dislocation rake angle). Preliminary locations of the NVT catalogue by Husker et al. (2010) for the Guerrero province confirmed the coastward spreading of the NVT activity during the 2006 Slow Slip Event, recently reported. Although the horizontal NVT-energy distribution changes along the one-dimensional MASE array from downdip to updip locations, our results show that this variation may be explained, for all NVT's, with approximately the same rake angle, which differs from the plate convergence direction by 15 to 20 degrees clockwise. Moreover, although a few NVT foci are located within the deep continental crust (i.e. between 30 and 40 km depth), most of the NVT activity is embedded within the subducted slab, below the 40 km depth Moho. Most of the intraslab activity lies between 200 and 240 km from the trench (region called the 'Sweet Spot' by Husker et al., 2012) with 40 to 50 km depth. By superimposing the NVT hypocentral cross-section locations over the state of pore pressure (Pp) computationally modeled within the slab due to the strain field induced by previous Slow Slip Events in the region (Cruz-Atienza et al., 2011), a surprisingly good spatial correlation appears between a low pore-pressure slab segment toward which fluids diffuse and the 'Sweet Spot', where most of the NVT bursts are systematically located.

Cruz-Atienza, V. M.; Husker, A. L.; Legrand, D.; Kostoglodov, V.

2013-05-01

363

Prestige centrality-based functional outlier detection in gene expression analysis  

PubMed Central

Motivation: Traditional gene expression analysis techniques capture an average gene expression state across sample replicates. However, the average signal across replicates will not capture activated gene networks in different states across replicates. For example, if a particular gene expression network is activated within a subset or all sample replicates, yet the activation state across the sample replicates differs by the specific genes activated in each replicate, the activation of this network will be washed out by averaging across replicates. This situation is likely to occur in single cell gene expression experiments or in noisy experimental settings where a small sub-population of cells contributes to the gene expression signature of interest. Results and Implementation: In this light, we developed a novel network-based approach which considers gene expression within each replicate across its entire gene expression profile, and identifies outliers across replicates. The power of this method is demonstrated by its ability to enrich for distant metastasis related genes derived from noisy expression data of CD44+CD24-/low tumor initiating cells. Contact: atorkama@scripps.edu; atorkama@scrippshealth.org Supplementary information: Supplementary data are available at Bioinformatics online.

Torkamani, Ali; Schork, Nicholas J.

2009-01-01

364

Treatment of a molasses based distillery effluent in a constructed wetland in central India.  

PubMed

A field-scale 4-celled, horizontal subsurface constructed wetland (CW) was installed to evaluate removal efficiencies of wastewater constituents in an industrial distillery effluent. Total and dissolved solids, NH4-N, TKN, P and COD were measured. This CW design provides four serial cells with synthetic liners and a river gravel base. The first two unplanted cells provide preliminary treatment. Specific gravel depths and ensuing biofilm growth provides anaerobic treatment in Cell 1 and anaerobic treatment in Cell 2. Cell 3 was planted with Typha latifolia with an inserted layer of brick rubble (for phosphorus removal). Locally grown reed, Phragmites karka was planted in Cell 4. COD was reduced from 8420 mg/l 3000 from Cell 1 to the outlet of Cell 4. Likewise other parameters: total and dissolved solids, ammonium and total nitrogen, and total P, indicated declining trends at the 4-celled CW effluent. This study reveals how high strength distillery wastewater strongly impacts morphology, aeration anatomy in the chiseled plant tissues, reed growth; and composition of the biofilm in the specialized substratum. The reliability of a CW for organic and nutrients reduction, in association with a poorly performing conventional system is discussed. There is an immense potential for appropriately designed constructed wetlands to improve high strength wastewaters in India. PMID:11804132

Billore, S K; Singh, N; Ram, H K; Sharma, J K; Singh, V P; Nelson, R M; Dass, P

2001-01-01

365

A new interpretation of the sedimentary cover in the western Siljan Ring area, central Sweden, based on seismic data  

NASA Astrophysics Data System (ADS)

Two new reflection seismic profiles over the Paleozoic successions of the western part of the Siljan Ring impact structure show a contrasting seismic signature. The more southerly c. 10 km long Mora profile reveals a highly disturbed structure, with only a few kilometers of relatively horizontally layered structures observed. However, interpretations of refracted arrivals in the data, that can be correlated to reflections, indicate the Silurian clastic rocks to be about 200 m thick in the central part of the profile. Weak reflections from about 600 m depth suggest a 400 m thick Ordovician limestone sequence to be present. Cores from the area show a mainly shale lithology for the Silurian and only a thin sequence of Ordovician strata, suggesting a rapid thickening of the Ordovician towards the north. On the more northern c. 12 km Orsa profile clear reflections from the Paleozoic successions are seen along the entire profile, except on the southernmost few kilometers. Based on interpretations of refracted arrivals, the Silurian succession appears to be considerably thinner here, and possibly absent at some locations. The Ordovician is also interpreted to be thinner in this area, with a maximum thickness of about 200-300 m along most of the profile. A deeper reflection from about 2 km within the crystalline basement may represent a dolerite sill. The lack of clear basement reflections on the Mora profile can be attributed to near-surface conditions and the acquisition geometry. The seismic data and recent coring in the area suggest the presence of a deeper paleo-basin towards the southwest with significantly more shales being deposited and the Paleozoic successions being severely disturbed. The shallow coring and seismic data will help form the basis for locating future boreholes for deeper drilling to study impact processes and the Paleozoic evolution of central Sweden.

Juhlin, Christopher; Sturkell, Erik; Ebbestad, Jan Ove R.; Lehnert, Oliver; Högström, Anette E. S.; Meinhold, Guido

2012-12-01

366

Late Quaternary alluvial fan response to climatic and tectonic base-level changes: Jakes Valley, Central Great Basin, USA  

NASA Astrophysics Data System (ADS)

Late Quaternary alluvial fans within the Jakes Valley region (White Pine County, Central Great Basin) are typically composed of up to 4 inset morphostratigraphic units. These units, Qf0 (oldest) through to Qf3 (youngest), are based upon field relationships (mapping & fan topographic profiles) and soil properties. Distal fan areas contain pluvial lake shoreline features (erosional benches and beach ridges) that record lake-level lowering since the last glacial maximum. Integration of the fan morphostratigraphy and pluvial lake shoreline features allows for the alluvial fan response to climate induced base-level lowering to be investigated. Geochronology is established by AMS C14 dating of gastropod shells sampled from a range of highstand (dates pending) through to lowstand (12,080 +/- 50 rcybp) beach ridges. Detailed analysis of two alluvial fans from the western (Cottonwood Fan) and eastern (Yamaha Fan) basin margins reveals some interesting differences in fan morphostratigraphy. The Cottonwood fan is characterised by a complete suite of morphostratigraphic units (Qf0-Qf3), whilst the Yamaha fan comprises only Qf0 and Qf3. The presence of a pronounced 17 m high scarp feature, some several hundreds of metres in length, within close proximity to the mountain front on the Cottonwood fan, suggests the occurrence of neotectonic activity. This extensional (?) faulting appears to be post QF0 and may have been responsible for influencing the observed stratigraphic differences between the Cottonwood and Yamaha fans via a tectonic lowering of base-level. Within this poster we explore the relative roles of climate and tectonic base-level lowering for alluvial fan development.

Stokes, M.; Garcia, A. F.

2003-12-01

367

Nanoparticle-based drug delivery to improve the efficacy of antiretroviral therapy in the central nervous system  

PubMed Central

Antiretroviral drug therapy plays a cornerstone role in the treatment of human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome patients. Despite obvious advances over the past 3 decades, new approaches toward improved management of infected individuals are still required. Drug distribution to the central nervous system (CNS) is required in order to limit and control viral infection, but the presence of natural barrier structures, in particular the blood–brain barrier, strongly limits the perfusion of anti-HIV compounds into this anatomical site. Nanotechnology-based approaches may help providing solutions for antiretroviral drug delivery to the CNS by potentially prolonging systemic drug circulation, increasing the crossing and reducing the efflux of active compounds at the blood–brain barrier, and providing cell/tissue-targeting and intracellular drug delivery. After an initial overview on the basic features of HIV infection of the CNS and barriers to active compound delivery to this anatomical site, this review focuses on recent strategies based on antiretroviral drug-loaded solid nanoparticles and drug nanosuspensions for the potential management of HIV infection of the CNS.

Gomes, Maria Joao; Neves, Jose das; Sarmento, Bruno

2014-01-01

368

Nanoparticle-based drug delivery to improve the efficacy of antiretroviral therapy in the central nervous system.  

PubMed

Antiretroviral drug therapy plays a cornerstone role in the treatment of human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome patients. Despite obvious advances over the past 3 decades, new approaches toward improved management of infected individuals are still required. Drug distribution to the central nervous system (CNS) is required in order to limit and control viral infection, but the presence of natural barrier structures, in particular the blood-brain barrier, strongly limits the perfusion of anti-HIV compounds into this anatomical site. Nanotechnology-based approaches may help providing solutions for antiretroviral drug delivery to the CNS by potentially prolonging systemic drug circulation, increasing the crossing and reducing the efflux of active compounds at the blood-brain barrier, and providing cell/tissue-targeting and intracellular drug delivery. After an initial overview on the basic features of HIV infection of the CNS and barriers to active compound delivery to this anatomical site, this review focuses on recent strategies based on antiretroviral drug-loaded solid nanoparticles and drug nanosuspensions for the potential management of HIV infection of the CNS. PMID:24741312

Gomes, Maria João; Neves, José das; Sarmento, Bruno

2014-01-01

369

An Evaluation of Incisor Relapse in Premolar Extraction and Nonextraction Patients Premolar Çekimli ve Çekimsiz Hastalarda Kesici Relapsinin De?erlendirilmesi  

Microsoft Academic Search

Objective: The purpose of this study was to evaluate the short-term postretention changes in four first premolar extraction and nonextraction patients to detect relapse in maxillary and mandibular dental arches and consider the associated factors with upper and lower incisor crowding. Subjects and Method: 15 cases were treated by four first premolar extraction and 30 cases without extraction. All of

TANER DDS; Derya GERMEÇ DDS

370

A comparative analysis between site-based and centralized ratings and patient self-ratings in a clinical trial of Major Depressive Disorder.  

PubMed

We compared scores from three different ratings methods in a clinical trial of patients with Major Depressive Disorder (MDD). The Quick Inventory of Depressive Symptoms (QIDS-SR16) was compared to site-based clinician and centralized (site-independent) ratings of the Inventory of Depressive Symptoms (IDSc30). An extracted QIDSc16 was used for a matched comparison with the QIDS-SR16. Patient self-ratings were more depressed at baseline than either site-based ratings (p = 0.131) or centralized ratings (p = 0.005), but significantly less depressed at the end of double-blind treatment than either site-based (p = 0.006) or centralized ratings (p = 0.014), and after 12 weeks (site-based ratings: p = 0.048; centralized ratings: p = 0.004). The matched comparisons with patient self-ratings revealed ICC of r = 0.55 (site-based raters) and r = 0.49 (centralized raters) at baseline. After baseline, the correlations between the two different clinician ratings and patient self-ratings improved to r-values between 0.78 and 0.89. At the end of double-blind treatment, site-based raters separated the combination treatment from placebo on the IDSc30 (p = 0.030) whereas neither centralized ratings nor patient self-ratings achieved statistical significance. Alternatively, patient self-ratings separated the combination treatment from buspirone (p = 0.030) whereas neither clinician rating method achieved significance. A "dual" scoring concordance range reduced the placebo response rate and increased the drug effect between the combination treatment and placebo. These findings reveal scoring variability between each of the three ratings methods and challenge the reliability of any single method to accurately assess symptom severity scores, particularly at baseline. The use of "dual" scoring criteria may help to confirm symptom severity scores and improve ratings precision, particularly prior to enrolling subjects into CNS trials. PMID:23562150

Targum, Steven D; Wedel, Pamela C; Robinson, Jill; Daniel, David G; Busner, Joan; Bleicher, Leo S; Rauh, Philip; Barlow, Carrolee

2013-07-01

371

Late Quaternary ostracode-based paleoenvironmental reconstructions from Lake Petén Itzá, Guatemala and Lake Chalco, central Mexico  

NASA Astrophysics Data System (ADS)

Modern and fossil ostracodes in lakes from central Mexico (Chalco) to lowland Guatemala (Petén Itzá) were used to infer paleoenvironmental conditions during the last 45 ka. Ostracode-based paleoenvironmental reconstruction from sediment cores in Lake Petén Itzá was based on a modern calibration data set from 63 water bodies in Guatemala, Mexico (Yucatán Peninsula) which provided information on the modern ecological preferences of 29 ostracode species. Statistical analysis indicated that lake water conductivity and chemical composition determine ostracode distributions on the Yucatán Peninsula and that lake level is a strong determinant of species distribution in Lake Petén Itzá. Transfer functions were applied to fossil species assemblages in long sediment cores from Lake Petén Itzá to infer past conductivity and lake level. Over the past 45 ka, ostracodes in Lake Petén Itzá were sensitive to fluctuations in lake water chemical composition and lake stage. Relative abundances of ostracode taxa and stable isotope values in their shells indicate large environmental changes from the LGM to deglaciation, and into the Holocene. The LGM was characterized by low species richness (n=4), dominance of benthic taxa, cold conditions and moderate to high lake levels. The deglaciation displayed higher species richness (n=6), dominance of nektobenthic taxa, and alternating dry and wet conditions, with low to relatively high lake levels. The Holocene was dominated by the deep-water ostracode Physocypria globula, indicating warmer temperatures and higher lake levels. Preliminary results from Lake Chalco sediment cores indicate ostracodes were scarce during the LGM and deglacial, but displayed higher abundances in older deposits. Ostracodes identified in the sediment record include Limnocythere sp., Candona patzcuaro and Darwinula stevensoni. The only species in common with the Lake Petén Itzá record is D. stevensoni. Deglacial species richness in Chalco (n=3) was lower than in Lake Petén Itzá (n=6). Because the species in Lake Chalco cores differ from those in the Petén Itzá record, a training set specifically for central Mexico was developed, using 28 water bodies. About 15 ostracode species have been identified and transfer functions to infer environmental variables will be developed. We will compare stable oxygen and carbon isotope records, measured on fossil ostracode remains in dated cores from Lakes Chalco and Petén Itzá, to infer past regional climate conditions.

Perez, L.; Lozano, S.; Caballero, M.; Brenner, M.; Schwalb, A.

2013-05-01

372

Is the lingual forming part of the incisor a structural entity? Evidences from the fragilitas ossium (fro/fro) mouse mutation and the TGFbeta1 overexpressing transgenic strain.  

PubMed

Our objective was to study the teeth of a mutant mice fro/fro that display severe forms of osteogenesis imperfecta. One day and 8 week-old fro/fro and +/fro heterozygote mice (wild type, WT) were processed for light and scanning electron microscopy. The genetic defect, shown to be located on chromosome 8, induced alveolar bone and teeth hypomineralisation. Due to defective cell proliferation in the fro/fro, the distal growth of the mandibular incisors was impaired. Immunolabelling revealed an increase of chondroitin/dermatan sulphate, whereas no difference was detected in dental tissues for decorin and biglycan. Amelogenin expression was decreased in the incisor and enhanced in the molar. Dentin sialoprotein was below the level of detection in the fro/fro, whereas osteonectin and osteopontin were unchanged. The main target of the mutation was seen in the lingual part of the incisor near the apex where dentine formation was delayed. In the molars, bulbous roots with obliteration of the pulp chamber were seen. In the TGFbeta1 overexpressing mice, the lingual root-analogue part of the incisor was missing. In the molar, short roots, circumpulpal dentine of the osteodentine type and pulp obliteration were seen. It may be noted that, although the mutant and transgenic strains mutations are two different genetic alterations not related to the same defective gene, in both cases the expression of the dentin sialoprotein is altered. Altogether, the present data suggest that the lingual forming part of the incisor seems to be an anatomical entity bearing its own biological specificities. PMID:15721162

Opsahl, S; Septier, D; Aubin, I; Guenet, J-L; Sreenath, T; Kulkarni, A; Vermelin, L; Goldberg, M

2005-02-01

373

GIS-based probability assessment of natural hazards in forested landscapes of Central and South-Eastern Europe.  

PubMed

We assessed the probability of three major natural hazards--windthrow, drought, and forest fire--for Central and South-Eastern European forests which are major threats for the provision of forest goods and ecosystem services. In addition, we analyzed spatial distribution and implications for a future oriented management of forested landscapes. For estimating the probability of windthrow, we used rooting depth and average wind speed. Probabilities of drought and fire were calculated from climatic and total water balance during growing season. As an approximation to climate change scenarios, we used a simplified approach with a general increase of pET by 20%. Monitoring data from the pan-European forests crown condition program and observed burnt areas and hot spots from the European Forest Fire Information System were used to test the plausibility of probability maps. Regions with high probabilities of natural hazard are identified and management strategies to minimize probability of natural hazards are discussed. We suggest future research should focus on (i) estimating probabilities using process based models (including sensitivity analysis), (ii) defining probability in terms of economic loss, (iii) including biotic hazards, (iv) using more detailed data sets on natural hazards, forest inventories and climate change scenarios, and (v) developing a framework of adaptive risk management. PMID:20535611

Lorz, C; Fürst, C; Galic, Z; Matijasic, D; Podrazky, V; Potocic, N; Simoncic, P; Strauch, M; Vacik, H; Makeschin, F

2010-12-01

374

FUCHS ENDOTHELIAL CORNEAL DYSTROPHY: SUBJECTIVE GRADING VERSUS OBJECTIVE GRADING BASED ON THE CENTRAL TO PERIPHERAL THICKNESS RATIO  

PubMed Central

Purpose To assess inter-observer agreement between two corneal specialists grading Fuchs dystrophy clinically, and to determine if the corneal central to peripheral thickness ratio (CPTR) might be an alternative and objective metric of disease severity. Design Cross-sectional study. Participants Forty-five eyes (26 subjects) with mild and moderate Fuchs dystrophy, 73 eyes (60 subjects) with advanced Fuchs dystrophy, and 267 eyes (142 subjects) with normal corneas. Methods Corneas with Fuchs dystrophy were graded by two corneal specialists based on the confluence and area of guttae, and the presence or absence of edema. Central corneal thickness (CCT) and peripheral corneal thickness at 4 mm from the center (PCT4) were measured by using scanning-slit pachymetry. CPTR4 was the quotient of CCT and PCT4. Main Outcome Measures Inter-observer agreement for clinical grade; CPTR4. Results Inter-observer agreement for clinical grading of Fuchs dystrophy was moderate (?=0.32, 95% confidence interval, 0.19-0.45). In normal corneas, CCT was not correlated with age (r= -0.10, p=0.28, n=267), PCT4 decreased with age (r= -0.33, p<0.001, n=254), and CPTR4 increased with age (r= 0.59, p<0.001, n=254). CCT was higher in Fuchs dystrophy (652 ± 61 ?m, n=118) than in normal corneas (559 ± 31 ?m, n=267, p<0.001). PCT4 was higher in Fuchs dystrophy (650 ± 51 ?m, n=107) than in normal corneas (643 ± 43 ?m, n=254, p<0.001 after adjusting thickness for age). CPTR4 was higher in advanced Fuchs dystrophy (1.03 ± 0.07, n=65) than in mild and moderate Fuchs dystrophy (0.95 ± 0.07, n=42, age-adjusted p<0.001), which in turn was higher than in normal corneas (0.87 ± 0.05, n=254, age-adjusted p<0.001). CPTR4 was highly correlated with clinical grade of Fuchs dystrophy (r=0.77, p<0.001, n=361). CPTR4 was repeatable (median coefficient of variation, 1.3%), and provided excellent discrimination between Fuchs dystrophy and normal (area under the receiver operator characteristic curve, 0.93). Conclusions Agreement between corneal specialists for the subjective and morphologic clinical grading of Fuchs dystrophy is only moderate. The corneal CPTR is an objective, repeatable, and possibly functional, metric of severity of Fuchs dystrophy that warrants further investigation to determine its role in monitoring disease progression and predicting the need for keratoplasty.

Repp, Daniel J.; Hodge, David O.; Baratz, Keith H.; McLaren, Jay W.; Patel, Sanjay V.

2012-01-01

375

Pliocene to Quaternary Central American tephrostratigraphy based on marine Tephras from ODP and DSDP sites - first comprehensive study  

NASA Astrophysics Data System (ADS)

The Central American Volcanic Arc (CAVA) is, and has been, one of the most active volcanic regions and generated numerous Plinian eruptions along his 1200 km extension. The best preserved archive of this volcanism can be found as ash layers in the marine sediments downwind from the volcanic sources on the Pacific floor. Numerous ash layers up to 8 Mio old, which occur in ODP and DSDP cores of Legs 66, 67, and 202, originated in Central America and southern Mexico. The cores lie across the ash distribution areas expected from dominant wind directions as identified by mapped fallout deposits. We have chosen 145 ash layers of all three Legs for first detailed analysis of these sites to built up a data base for upcoming IODP cruise 334: Costa Rica Seismogenesis Project. The ash layers commonly have sharp contacts at the bottom and diffuse transitions to terrigenous and pelagic sediments at the top. Ash layer thickness ranges from 0.5 to 60 cm with typical grain sizes from medium silt to coarse sand. The mineral assemblages are typical for arc volcanism (plagioclase, pyroxene, hornblende, and olivine). The most evolved tephras also contain biotite. Electron microprobe analyses of 1300 glass shards yield compositions ranging from basaltic andesite to rhyolite and trachyte. Felsic ashes can be divided into seven compositional groups by means of silica and potassium contents. Correlations between marine ashes and on-land tephras are constrained by petrographical and stratigraphical criteria, major element geochemistry of glasses and minerals, and trace element data from LA-ICP-MS analyses. Due to limited exposure on land, such correlations with individual tephras are only possible for deposits of late Pleistocene to Holocene age. Older ash layers, however, can be correlated with regional arc segments making use of systematic along-arc variations of trace-element characteristics (Zr/Nb, Ba/La, Ce/Yb, La/Yb and Ba/Zr) of the arc rocks. Results show that source areas of the ash layers are distributed along the entire CAVA, as well as at the Southern Mexican Arc. The marine tephra record provides important data for ongoing studies of CAVA volcanism: (a) dating of undated land tephra by correlation with marine ashes and the ages derived by sedimentation rates; (b) stratigraphic correlations along the entire arc can be traced much more completely in the marine sediment cores than by limited onshore outcrops alone; (c) long-term changes in magmatic evolution of volcanic complexes can be reconstructed by using the marine archive of ash layers.

Strehlow, K.; Kutterolf, S.; Freundt, A.; Kwasnitschka, T.

2010-12-01

376

A three-dimensional slope stability model based on GRASS GIS and its application to the Collazzone area, Central Italy  

NASA Astrophysics Data System (ADS)

Landslide risk depends on landslide hazard, i.e. the probability of occurrence of a slope failure of a given magnitude within a specified period and in a given area. The occurrence probability of slope failures in an area characterized by a set of geo-environmental parameters gives the landslide susceptibility. Statistical and deterministic methods are used to assess landslide susceptibility. Deterministic models based on limit equilibrium techniques are applied for the analysis of particular types of landslides (e.g., shallow soil slips, debris flows, rock falls), or to investigate the effects of specific triggers, i.e., an intense rainfall event or an earthquake. In particular, infinite slope stability models are used to calculate the spatial probability of shallow slope failures. In these models, the factor of safety is computed on a pixel basis, assuming a slope-parallel, infinite slip surface. Since shallow slope failures coexist locally with deep-seated landslides, infinite slope stability models fail to describe the complexity of the landslide phenomena. Limit equilibrium models with curved sliding surfaces are geometrically more complex, and their implementation with raster-based GIS is a challenging task. Only few attempts were made to develop GIS-based three-dimensional applications of such methods. We present a preliminary implementation of a GIS-based, three-dimensional slope stability model capable of dealing with deep-seated and shallow rotational slope failures. The model is implemented as a raster module (r.rotstab) in the Open Source GIS package GRASS GIS, and makes use of the three-dimensional sliding surface model proposed by Hovland (1977). Given a DEM and a set of thematic layers of geotechnical and hydraulic parameters, the model tests a large number of randomly determined potential ellipsoidal slip surfaces. In addition to ellipsoidal slip surfaces, truncated ellipsoids are tested, which can occur in the presence of weak layers or hard bedrock. Any raster cell may be intersected by various sliding surfaces, each associated with a computed factor of safety. The lowest value of the factor of safety is stored for each raster cell together with the depth of the associated slip surface. This results in an overview of potentially unstable regions without showing the individual sliding areas. We test the model in the Collazzone area, Umbria, Central Italy, which is susceptible to landslides of different types. The presence of both shallow translational and deep-seated rotational landslides, and the availability of reference data, allow for the critical evaluation of the model in comparison with standard infinite slope stability models.

Mergili, M.; Marchesini, I.; Fellin, W.; Rossi, M.; Raia, S.; Guzzetti, F.

2012-04-01

377

Efficacy of two cannabis based medicinal extracts for relief of central neuropathic pain from brachial plexus avulsion: results of a randomised controlled trial  

Microsoft Academic Search

The objective was to investigate the effectiveness of cannabis-based medicines for treatment of chronic pain associated with brachial plexus root avulsion. This condition is an excellent human model of central neuropathic pain as it represents an unusually homogenous group in terms of anatomical location of injury, pain descriptions and patient demographics. Forty-eight patients with at least one avulsed root and

Jonathan S. Berman; Catherine Symonds; Rolfe Birch

2004-01-01

378

Seismicity in Central North Africa at low magnitudes: A first look at the TAM event detected data base  

SciTech Connect

Teleseismic observations of seismicity in the central North Africa region show that the region is aseismic. This is true for earthquakes with a body wave magnitude greater than about 4 or so. For earthquakes with body wave magnitudes substantially below about 4, the teleseismic observations of seismicity in the central Sahara are incomplete since smaller earthquakes would probably not be detected and located by the current teleseismic monitoring networks. Only one known open seismic station has been operating in the central Sahara. This is the Tamanrasset (TAM) seismic station in southern Algeria. A simple analysis of data records from this station can be used to determine if the central Sahara is also relatively aseismic at magnitudes substantially below 4. That is the primary purpose of this study.

Harben, P.E.,

1997-01-01

379

Preliminary Results of the Active Source Portion of the Bighorns Array Seismic Experiment (BASE), North-Central Wyoming, USA  

NASA Astrophysics Data System (ADS)

The Bighorn Arch Seismic Experiment (BASE), is designed to image the Bighorn Arch in North Central Wyoming using active and passive seismic methods. The Bighorn Mountains formed as a basement involved foreland arch during the Laramide Orogeny. Whereas such arches are major features of both modern and ancient contractional orogens, the manifestation of arch shortening at depth has been highly contested due to the absence of detailed geophysical imaging of crust and mantle beneath the arches. BASE is a component of an integrated geological-geophysical program, the Bighorns Project, focused on discovering the nature of features that accommodate shortening at depth in such orogens. The active component of BASE was conducted in two deployments during the summer of 2010 and was designed to image the crust and upper mantle of the region. During the first deployment, ca. 1800 single channel Texan seismographs were deployed at 100 and 500 m spacings along a north-south profile located on the west flank of the Bighorn Mountains and along an east-west profile that extended across the arch from near Cody, Wyoming to north of Gillette, Wyoming. The seismograph array recorded blasts at 16 locations over two nights. The second deployment recorded 8 shots on ~800 Texan seismographs deployed at 200 and 1000 m spacings along the same north-south and east-west profiles. These shots were also recorded by ~400 additional Texans seismographs with 1 km spacing on a larger grid that encompassed the entire arch. Preliminary review of the data shows that shot energy propagated to offsets as great as 270 km and that large delays and advances in first arrival times correlate with the location of basins and exposed basement rocks respectively. Early one-dimensional velocity models show that the crystalline crust has velocities of 6.1 to 6.5 km/s to depths of ca 22 km, below which velocities increase from 6.8 to 7.0 km/s Crustal thickness appears to vary between 35 and 45 km. Future work includes developing velocity models from seismic tomography that will show what type of basement structures exist beneath the mountains, and, after integration with other datasets, how their geometries change in two- and three-dimensions.

Terbush, B. R.; Worthington, L. L.; Miller, K. C.; Harder, S. H.; Erslev, E.; Anderson, M. L.; Siddoway, C. S.

2010-12-01

380

A COMPARATIVE STUDY OF RADIOFREQUENCIES FIELD LEVELS OF SOME BASE STATIONS IN MAKURDI AND ITS ENVIRONS IN BENUE STATE, NORTH CENTRAL NIGERIA  

Microsoft Academic Search

A comparative study of radiofrequencies field levels of some base stations in Makurdi and its environs was carried out in Makurdi, Benue State, North central Nigeria. Electromagnetic field tester (EMF 827 Lutron) was used for measurement at distances ranging from 5.00, 10.00, 15.00 and 20.00 meters away from the base stations at the North, South, West and East directions. Electric

J. T Iortile; L. Alumuku

2014-01-01

381

Detection of Planets in Extremely Weak Central Perturbation Microlensing Events via Next-generation Ground-based Surveys  

NASA Astrophysics Data System (ADS)

Even though the recently discovered high-magnification event MOA-2010-BLG-311 had complete coverage over its peak, confident planet detection did not happen due to extremely weak central perturbations (EWCPs, fractional deviations of <~ 2%). For confident detection of planets in EWCP events, it is necessary to have both high cadence monitoring and high photometric accuracy better than those of current follow-up observation systems. The next-generation ground-based observation project, Korea Microlensing Telescope Network (KMTNet), satisfies these conditions. We estimate the probability of occurrence of EWCP events with fractional deviations of <=2% in high-magnification events and the efficiency of detecting planets in the EWCP events using the KMTNet. From this study, we find that the EWCP events occur with a frequency of >50% in the case of <~ 100 M E planets with separations of 0.2 AU <~ d <~ 20 AU. We find that for main-sequence and sub-giant source stars, >~ 1 M E planets in EWCP events with deviations <=2% can be detected with frequency >50% in a certain range that changes with the planet mass. However, it is difficult to detect planets in EWCP events of bright stars like giant stars because it is easy for KMTNet to be saturated around the peak of the events because of its constant exposure time. EWCP events are caused by close, intermediate, and wide planetary systems with low-mass planets and close and wide planetary systems with massive planets. Therefore, we expect that a much greater variety of planetary systems than those already detected, which are mostly intermediate planetary systems, regardless of the planet mass, will be significantly detected in the near future.

Chung, Sun-Ju; Lee, Chung-Uk; Koo, Jae-Rim

2014-04-01

382

Crustal-scale structural architecture in central Chile based on seismicity and surface geology: Implications for Andean mountain building  

NASA Astrophysics Data System (ADS)

We document a crustal-scale structural model for the central Chile Andes based on seismicity and surface geology, which consists in a major east verging ramp-detachment structure connecting the subduction zone with the cordillera. The ramp rises from the subducting slab at ˜60 km depth to 15-20 km below the western edge of the cordillera, extending eastward as a 10 km depth flat detachment. This structure plays a fundamental role in the Andean orogenesis because most of the shortening has been accommodated by structures rooted in it and allows the distribution of crustal thickening in a "simple shear deformation mode." Indeed, despite shortening distribution being very asymmetric (˜16 km versus ˜70 km in the western and eastern side, respectively), the western side is higher and thicker than what is expected. Yield strength envelopes show strong rheological control on this structure. Vp and Vp/Vs variations in the upper mantle and in the deepest limit of the seismogenic interplate contact mark the intersection of the ramp with the slab, which coincides with the blueschist-eclogite transition. Therefore, subduction processes would control the depth where the major east verging structure may merge with the slab. Such a ramp-flat structure is observed in other parts of the Chilean margin; hence, it seems to be a first-order feature in the Andean subduction zone. This structure delimitates upward the rocks, transmitting part of the plate convergence stress from the plate interface, and controls mountain-building tectonics, thus playing a key role in the Andean orogeny.

FaríAs, Marcelo; Comte, Diana; Charrier, Reynaldo; Martinod, Joseph; David, Claire; Tassara, AndréS.; Tapia, Felipe; Fock, AndréS.

2010-06-01

383

Reinterpretation of Paleoproterozoic accretionary boundaries of the north-central United States based on a new aeromagnetic-geologic compilation  

USGS Publications Warehouse

The Paleoproterozoic crust in the north-central U.S. represents intact juvenile terranes accreted to the rifted Archean Superior craton. A new tectonic province map, based on the interpretation of a new aeromagnetic compilation, published geologic maps, and recent geochronologic data, shows progressive accretion of juvenile arc terranes from ca. 1900-1600 Ma. Contrary to earlier models, geon 18 Penokean-interval crust is primarily confined to a ???2100 Ma tectonic embayment of the rifted Superior craton. The newly defined Spirit Lake tectonic zone, characterized by a sharp magnetic discontinuity that marks the southern limit of Archean and Penokean-interval rocks, is here interpreted to represent an eastern analog of the Cheyenne belt suture zone in southern Wyoming. South of this boundary, geon 17 Yavapai-interval rocks form the basement upon which 1750 Ma rhyolite and succeeding quartzite sequences were deposited. Substantial portions of the Penokean and Yavapai terranes were subsequently deformed during the 1650-1630 Ma Mazatzal orogeny. The northern boundary of the Mazatzal terrane is obscured by abundant 1470-1430 Ma "anorogenic" plutons that stitched the suture with the older Yavapai terrane rocks. These data reveal a progressive tectonic younging to the south as the Laurentian craton grew southward and stabilized during the Proterozoic. Late Mesoproterozoic rift magmatism produced pronounced geophysical anomalies, indicating strong, but localized crustal modification. In comparison to the western U.S., little tectonism has occurred here in the last 1 billion years, providing a uniquely preserved record of the Precambrian evolution of the continental U.S. lithosphere. ?? 2007 Elsevier B.V. All rights reserved.

Holm, D. K.; Anderson, R.; Boerboom, T. J.; Cannon, W. F.; Chandler, V.; Jirsa, M.; Miller, J.; Schneider, D. A.; Schulz, K. J.; Van Schmus, W. R.

2007-01-01

384

Enhancing a global satellite-based Landslide hazard Algorithm with regional applications in Central America and the Caribbean  

NASA Astrophysics Data System (ADS)

A satellite-based landslide algorithm has been developed using land surface information and multi-satellite rainfall data to address landslide susceptibility dynamically. The evaluation of this global system indicates that principally three factors limit the algorithm's performance, including unsuitable weighting of several surface input parameters to the susceptibility map, under-estimation of rainfall accumulations, and incompleteness of the landslide inventories. To address these limitations and refine the methodology used to calculate the input variables for the algorithm this research considers the algorithm components at a regional scale focusing on Central America and the Caribbean. Drawing upon available landslide inventories and higher resolution surface products including Shuttle Radar Topography Mission (SRTM) DEMs, land cover, and other parameters, this study identifies regional landslide susceptibility by employing several different techniques. Susceptibility maps are compiled for multiple test regions and compared using sensitivity analysis of the input surface parameters, indicating which factors are the primary drivers of successful susceptibility calculations. The rainfall triggering relationship is also considered at the regional scale, considering both in situ and satellite data to better resolve the range of potential rainfall threshold conditions. Additional variables such as soil moisture can be integrated into the susceptibility and rainfall variables to provide a more dynamic estimation of potential landsliding conditions. Regional landslide vulnerability data can then be extracted by incorporating socio-economic data including population density and transportation networks. The improved inputs can then be tested in a regional version of the landslide algorithm and validated for system performance. The results of the regional study indicate that resolution of the input parameters can significantly affect the susceptibility calculations and the rainfall relationship remains a difficult aspect of the algorithm to effectively categorize; however, approaching the algorithm at the regional scale improves algorithm performance and is a crucial component of the second version of this global system.

Kirschbaum, D. B.; Lerner-Lam, A.; Adler, R.; Hong, Y.; Teng, B.

2008-12-01

385

Central Pontine Myelinolysis  

Microsoft Academic Search

Central pontine myelinolysis (CPM) is a demyelinating disease of the pons often associated with demyelination of other areas of the central nervous system (CNS). The term ‘osmotic demyelinization syndrome’ is used for pontine and extrapontine myelinolysis. In this paper, we are concerned with CPM although the extrapontine one is based on the same pathogenesis. Both share the diagnostic methods, and

Christian Lampl; Kambiz Yazdi

2002-01-01

386

Effects of aliskiren- and ramipril-based treatment on central aortic blood pressure in elderly with systolic hypertension: a substudy of AGELESS  

PubMed Central

Background Systolic hypertension is the most common form of hypertension in elderly patients. There is increasing evidence that measurement of central aortic pressure (CAP) better accounts for cardiovascular risk than brachial blood pressure (BP). The Aliskiren for GEriatric LowEring of SyStolic hypertension (AGELESS) study in elderly patients with systolic hypertension showed that aliskiren-based therapy provided greater reductions in peripheral BP than ramipril-based therapy over 12 and 36 weeks of treatment. Here, we present CAP results in a substudy of elderly patients from the AGELESS study. Methods This was a post hoc analysis of a 36-week, randomized, double-blind, parallel-group, active-controlled, optional-titration study in patients ?65 years of age with systolic BP ?140 mmHg. Changes in both central and peripheral BP and pulse pressure (PP) and changes in systolic and PP amplification ratios from baseline to the week 36 end point with aliskiren-based versus ramipril-based therapy were analyzed. Results Of the 901 patients randomized in the overall study, 154 patients (aliskiren, n=78; ramipril, n=76) had CAP data. Numerically comparable reductions were seen for central aortic systolic pressure (CASP) in aliskiren-based therapy (baseline: 143.7±15.0; week 36: ?20.3±16.2) compared with ramipril-based therapy (baseline: 147.9±11.9; week 36: ?20.7±14.6). However, for the change in central aortic diastolic pressure, the least squares mean between-treatment difference (?3.6 mmHg [95% confidence interval, ?6.76, ?0.43; P=0.0263]) was in favor of aliskiren, while the other changes were comparable between the two groups with a trend in favor of aliskiren for CASP as well (?2.6 mmHg [95% confidence interval, ?7.38, 2.19; P=0.2855)]. Correlation coefficients for change from baseline between CASP and systolic BP and between central aortic pulse pressure and PP (r=0.8, P<0.0001) were highly significant. Conclusion Aliskiren-based therapy provides comparable reductions in CASP to ramipril-based therapy. Although the results did not reach statistical significance, these findings, when coupled with those of the main study, suggest that aliskiren may offer effective control of central BP in elderly patients with systolic hypertension and may be a good alternative to ramipril.

Baschiera, Fabio; Chang, William; Brunel, Patrick

2014-01-01

387

ScienceCentral: open access full-text archive of scientific journals based on Journal Article Tag Suite regardless of their languages  

PubMed Central

ScienceCentral, a free or open access, full-text archive of scientific journal literature at the Korean Federation of Science and Technology Societies, was under test in September 2013. Since it is a Journal Article Tag Suite-based full text database, extensible markup language files of all languages can be presented, according to Unicode Transformation Format 8-bit encoding. It is comparable to PubMed Central: however, there are two distinct differences. First, its scope comprises all science fields; second, it accepts all language journals. Launching ScienceCentral is the first step for free access or open access academic scientific journals of all languages to leap to the world, including scientific journals from Croatia.

Huh, Sun

2013-01-01

388

ScienceCentral: open access full-text archive of scientific journals based on Journal Article Tag Suite regardless of their languages.  

PubMed

ScienceCentral, a free or open access, full-text archive of scientific journal literature at the Korean Federation of Science and Technology Societies, was under test in September 2013. Since it is a Journal Article Tag Suite-based full text database, extensible markup language files of all languages can be presented, according to Unicode Transformation Format 8-bit encoding. It is comparable to PubMed Central: however, there are two distinct differences. First, its scope comprises all science fields; second, it accepts all language journals. Launching ScienceCentral is the first step for free access or open access academic scientific journals of all languages to leap to the world, including scientific journals from Croatia. PMID:24266292

Huh, Sun

2013-01-01

389

Validation and future predictions based on a new Non-Point Source Assessment Toolbox, applied to the Central Valley, California  

NASA Astrophysics Data System (ADS)

Groundwater is a major irrigation water source in semi-arid regions. It is also vulnerable to Non-Point Source (NPS) contamination, particularly from nitrate (NO3-) as a result of agricultural practices. To support sound policy decisions we developed a physically based flow and transport model framework to understand and predict the fate of contaminants within regional aquifer systems. In large aquifers, the total source area of pollutants typically cover several thousand square kilometers, whilst individual sources typically do not exceed a few hundred square meters. The large contrast in these scenarios result in NPS modeling tasks that are computationally demanding, and the classical 3D models that solve the Advection-Dispersion Equation (ADE) are often not applicable due to computer memory limitations, numerical dispersion and numerical instabilities. Here, we developed and employed a number of numerical techniques to assemble a Non-Point Source Assessment Toolbox (NPSAT). The NPSAT is a quasi-3D model, combining a flow model and a streamline transport model. The flow model solves the groundwater flow equation using very fine discretization. For very large groundwater basins, a simplistic decomposition method is applied, splitting the aquifer into several overlapping sub-domains and solving to produce a high resolution velocity field. This velocity field is subsequently utilized within the transport model, where backward particle tracking links contamination sources with discharge surfaces using a large number of streamlines. For each streamline the 1D ADE is solved, assuming a unit pulse loading at the source side and a free exit boundary condition at the discharge surface side. From this, a Unit Response Function (URF) is obtained at the discharge surface side. Subsequently, actual Breakthrough Curves (BTCs) can be quickly computed from actual or hypothetical loading histories, by convoluting the URFs with real loading functions. The URFs are stored into a GIS platform and can be used for efficient scenario evaluations without the need to repeat groundwater model simulations. This method is applied to the southern third part of the Central Valley Aquifer, California, which is an intensively farmed semi-arid area, where the local communities rely heavily on groundwater. To obtain a detailed velocity field, the Central Valley Hydrologic Model (CVHM) developed by the USGS was used as the coarse solution, split and refined into a large number of sub-domains. The CVHM resolution is 1 sq mi, with the stresses applied to the center of each cell. In our refined model the well stresses are spatially distributed to a large number of hypothetical wells, where the pumping rates, well depths and screen lengths are obtained from empirical probability distributions, derived from real data. The NPSAT generates a time-dependent water quality probability distribution, which express the time-dependent probability for a discharge surface (e.g., well) to exceed a threshold level of contamination across at a specific time. The model result is compared against real historic nitrate data, and used for future predictions with different scenario evaluations.

Kourakos, G.; Harter, T.

2011-12-01

390

The carpenter fork bed, a new - and older - Black-shale unit at the base of the New Albany shale in central Kentucky: Characterization and significance  

USGS Publications Warehouse

Black shales previously interpreted to be Late Devonian cave-fill or slide deposits are shown to be much older Middle Devonian black shales only preserved locally in Middle Devonian grabens and structural lows in central Kentucky. This newly recognized - and older -black-shale unit occurs at the base of the New Albany Shale and is named the Carpenter Fork Bed of the Portwood Member of the New Albany Shale after its only known exposure on Carpenter Fork in Boyle County, central Kentucky; two other occurrences are known from core holes in east-central Kentucky. Based on stratigraphic position and conodont biostratigraphy, the unit is Middle Devonian (Givetian: probably Middle to Upper P. varcus Zone) in age and occurs at a position represented by an unconformity atop the Middle Devonian Boyle Dolostone and its equivalents elsewhere on the outcrop belt. Based on its presence as isolated clasts in the overlying Duffin Bed of the Portwood Member, the former distribution of the unit was probably much more widespread - perhaps occurring throughout western parts of the Rome trough. Carpenter Fork black shales apparently represent an episode of subsidence or sea-level rise coincident with inception of the third tectophase of the Acadian orogeny. Deposition, however, was soon interrupted by reactivation of several fault zones in central Kentucky, perhaps in response to bulge migration accompanying start of the tectophase. As a result, much of central Kentucky was uplifted and tilted, and the Carpenter Fork Bed was largely eroded from the top of the Boyle, except in a few structural lows like the Carpenter Fork graben where a nearly complete record of Middle to early Late Devonian deposition is preserved.

Barnett, S. F.; Ettensohn, F. R.; Norby, R. D.

1996-01-01

391

Urokinase-type Plasminogen Activator mRNA is Expressed in Normal Developing Teeth and Leads to Abnormal Incisor Enamel in ?MUPA Transgenic Mice  

Microsoft Academic Search

The urokinase-type plasminogen activator (uPA) is a secreted, inducible serine protease implicated in extracellular proteolysis\\u000a and tissue remodeling. Here we detected uPA mRNA through in situ hybridization in developing molar and incisor teeth of normal mice at multiple sites of the cap and bell developmental stages.\\u000a The mRNA was confined to epithelial cells, however, was undetectable in ameloblasts or their

Ruth Miskin; Tamar Masos; Zipi Shoham; Lisa Williams-Simons

2006-01-01

392

Increase of MT1-MMP, TIMP-2 and Ki67 proteins in the odontogenic region of the rat incisor post-shortening procedure  

Microsoft Academic Search

MT1-MMP and TIMP-2 are well known for their roles in remodelling of extracellular matrix components. However, reports are\\u000a emerging on the involvement of these molecules in cell kinetics. In the rat incisor tooth, a shortening treatment increases\\u000a the eruption and cell proliferation rates. However, the role of MT1-MMP and TIMP-2 proteins in these processes is still to\\u000a be evaluated. Male

Jose Rosa Gomes; Nádia Fayez Omar; Juliana dos Santos Neves; Eliene Aparecida Orsini Narvaes; Pedro Duarte Novaes

2010-01-01

393

Adapting to Climate Variability and Change: Experiences from Cereal-Based Farming in the Central Rift and Kobo Valleys, Ethiopia  

NASA Astrophysics Data System (ADS)

Small-holder farmers in Ethiopia are facing several climate related hazards, in particular highly variable rainfall with severe droughts which can have devastating effects on their livelihoods. Projected changes in climate are expected to aggravate the existing challenges. This study examines farmer perceptions on current climate variability and long-term changes, current adaptive strategies, and potential barriers for successful further adaptation in two case study regions—the Central Rift Valley (CRV) and Kobo Valley. The study was based on a household questionnaire, interviews with key stakeholders, and focus group discussions. The result revealed that about 99 % of the respondents at the CRV and 96 % at the Kobo Valley perceived an increase in temperature and 94 % at CRV and 91 % at the Kobo Valley perceived a decrease in rainfall over the last 20-30 years. Inter-annual and intraseasonal rainfall variability also has increased according to the farmers. The observed climate data (1977-2009) also showed an increasing trend in temperature and high inter-annual and intra-seasonal rainfall variability. In contrast to farmers’ perceptions of a decrease in rainfall totals, observed rainfall data showed no statistically significant decline. The interaction among various bio-physical and socio-economic factors, changes in rainfall intensity and reduced water available to crops due to increased hot spells, may have influenced the perception of farmers with respect to rainfall trends. In recent decades, farmers in both the CRV and Kobo have changed farming practices to adapt to perceived climate change and variability, for example, through crop and variety choice, adjustment of cropping calendar, and in situ moisture conservation. These relatively low-cost changes in farm practices were within the limited adaptation capacity of farmers, which may be insufficient to deal with the impacts of future climate change. Anticipated climate change is expected to impose new risks outside the range of current experiences. To enable farmers to adapt to these impacts critical technological, institutional, and market-access constraints need to be removed. Inconsistencies between farmers’ perceptions and observed climate trends (e.g., decrease in annual rainfall) could lead to sub-optimal or counterproductive adaptations, and therefore must be removed by better communication and capacity building, for example through Climate Field Schools. Enabling strategies, which are among others targeted at agricultural inputs, credit supply, market access, and strengthening of local knowledge and information services need to become integral part of government policies to assist farmers to adapt to the impacts of current and future climate change.

Kassie, Belay Tseganeh; Hengsdijk, Huib; Rötter, Reimund; Kahiluoto, Helena; Asseng, Senthold; Van Ittersum, Martin

2013-11-01

394

Holocene glacier history of Bjørnbreen and climatic reconstruction in central Jotunheimen, Norway, based on proximal glaciofluvial stream-bank mires  

NASA Astrophysics Data System (ADS)

Holocene variations of Bjørnbreen, Smørstabbtinden massif, west-central Jotunheimen are reconstructed from the lithostratigraphy of two alpine stream-bank mires flooded episodically by meltwater. The approach uses multiple sedimentological indicators (weight loss-on-ignition, mean grain size, grain-size fractions, bulk density, moisture content and magnetic susceptibility), an a priori model of overbank deposition of suspended glaciofluvial sediments, a detailed chronology based on 56 radiocarbon dates, and a Little Ice Age sedimentological analogue. Rapid, late-Preboreal deglaciation was indicated by immigration of Betula pubescens by 9700 cal. BP. An interval of at least 3000 years in the early Holocene when glaciers were absent was interrupted by two abrupt episodes of glacier expansion around the time of the Finse Event, the first at ca 8270-7900 cal. BP (Bjørnbreen I Event) and the second at ca 7770-7540 cal. BP (Bjørnbreen II Event). Neoglaciation began shortly before ca 5730 cal. BP with gradual build-up to the maximum of the Bjørnbreen III Event at ca 4420 cal. BP. Later maxima occurred at ca 2750 cal. BP (Bjørnbreen IV Event) and at 1300, 1260, 1060 and 790 cal. BP (all within the Bjørnbreen V Event). Glaciers were smaller than today and possibly melted away on several occasions in the late Holocene (ca 3950, 1410 and 750 cal. BP). Minor maxima also occurred at ca 660 and 540 cal. BP, within the late Mediaeval Warm Period and the early Little Ice Age, respectively. The Little Ice Age maximum was dated to 213±25 BP (ca 205 cal. BP). The relative magnitudes of the main glacier maxima were determined: Erdalen Event>Little Ice Age Event (Bjørnbreen VI)>Bjørnbreen I (Finse Event) ? Bjørnbreen II>Bjørnbreen V?Bjørnbreen IV>Bjørnbreen III. These episodic events of varying magnitude and abruptness were used in conjunction with an independent summer-temperature proxy to reconstruct variations in equilibrium-line altitude (ELA) and a Holocene record of winter precipitation. Since the Preboreal, ELA varied within a range of about 390 m, and winter precipitation ranged between 40 and 160% of modern values. Winter precipitation variations appear to have been the main cause of these century- to millennial-scale Holocene glacier variations.

Matthews, John A.; Berrisford, Mark S.; Quentin Dresser, P.; Nesje, Atle; Olaf Dahl, Svein; Elisabeth Bjune, Anne; Bakke, Jostein; John, H.; Birks, B.; Lie, Øyvind; Dumayne-Peaty, Lisa; Barnett, Catherine

2005-01-01

395

Effect of the X-linked gene Tabby (Ta) on eyelid opening and incisor eruption in neonatal mice is opposite to that of epidermal growth factor.  

PubMed

Studies on eyelid opening and incisor eruption in 216 neonatal Tabby (Ta)-bearing mice and wildtype controls (35 Ta/Y, 62 + /Y, 30 Ta/Ta, 57 Ta/+ and 32 +/+) showed that in animals hemizygous and homozygous for Ta, the timing of eyelid opening and incisor eruption was significantly delayed (P less than 0.05). It was also observed that once open, the eyes of mutant pups do not remain open for long but soon close again for several days before reopening. An iterative eyes open-eyes closed process seems to continue beyond puberty. Studies in 25 epidermal growth factor (EGF)-treated mutants and 23 saline-treated controls showed that neonatal EGF injections (4 micrograms g-1 body weight per day) reversed the delayed timing of eyelid opening and incisor eruption in hemizygote and homozygote Tabby mice. However, both mutant and wildtype EGF-treated mice also showed the eyes open-eyes closed cycle, whereas untreated nonmutant mice did not. Because Tabby appears to be genetically homologous to the gene for human X-linked hypohidrotic ectodermal dysplasia, these results may have potential clinical significance. The eyes open-eyes closed cycle may involve cycling levels of EGF receptor; since the gene for this receptor shows homology with an oncogene, this system may be useful in studies on genetic control of oncogene function. PMID:2351074

Kapalanga, J; Blecher, S R

1990-02-01

396

Scanning electron microscopic quantitative study of changes with age in closing pattern of openings of dentinal tubules on worn occlusal surfaces of Japanese permanent mandibular incisors.  

PubMed

Age-related changes in the closing of dentinal tubules of Japanese permanent mandibular incisors were surveyed using a non-destructive replication technique suitable for SEM analysis at the magnifications of up to X3,000. The areas of openings of dentinal tubules on occlusal surfaces decreased significantly between a 20-39-year age group and a 40+ age group, but the number of the openings tended to decrease. Heavy toothwear on occlusal surfaces of these Japanese permanent incisors was evident even at 27 years of age. A subject of 30 years of age showed surprisingly small number of the opening of dentinal tubules on occlusal surface. The occlusal surfaces became smoother in 40-59-year age group as closure of dentinal tubules of openings increased. Early heavy toothwear and early closure of the openings of dentinal tubules may be related to Japanese ethnic diet such as dried hard sardines whole which contain hard bones. Japanese often crush shells of crabs and shrimp with their incisors and canines as they eat. PMID:2094005

Hojo, T

1990-12-01

397

Causes and prevalence of traumatic injuries to the permanent incisors of school children aged 10-14 years in Maseru, Lesotho.  

PubMed

Traumatic dental injuries are widespread in the population and the prevalence of traumatic dental injuries among school children in different parts of the world varies from about 3% to 45%. Most injuries involve the anterior teeth, which may lead to eating restrictions, changes in physical appearance, speech defects and psychological impacts that affect the child's quality of life. A cross-sectional survey was carried out to investigate the prevalence, aetiology and types of injuries to permanent incisors among schoolchildren aged 10-14 years from Maseru, Lesotho. Upper and lower permanent incisors were examined for dental injuries. The prevalence of traumatic injuries to the permanent incisor teeth was 9.3% (13.3% boys and 6.3% girls). Significantly more boys than girls suffered injury. The most common type of injury was enamel fractures and most common cause was falls. Health promotion policies should aim to create an appropriate and safe environment for children. Soft playground surfaces, school-crossing patrols, marked zebra crossings and bicycle lanes would help create a safe environment. Speed limits for cars and the use of seat belts, air bags, special car seats for children and bicycle helmets should be enforced. Mouth guards should be used when playing sport, in particular contact sports. Education regarding the epidemiology of dental injuries and their prevention through health promotion may play a major role in reducing the prevalence of dental injury and avoiding the financial costs of treatment, especially in developing countries. PMID:18689347

Lin, H; Naidoo, Sudeshni

2008-04-01

398

Determining central activation failure and peripheral fatigue in the course of sustained maximal voluntary contractions: a model-based approach  

Microsoft Academic Search

In the study of fatigue, several methods have been used to calculate the development of central activation failure (CAF) and peripheral fatigue (PF) in the course of a sustained maximal voluntary contraction (MVC). This paper presents a model that enables simultaneous determination of CAF and PF during sustained MVC by using only force registration and superimposed electrical stimulation. In the

Maartje L. Schillings; Dick F. Stegeman; Machiel J. Zwarts

2005-01-01

399

Evaporation of intercepted precipitation based on an energy balance in unlogged and logged forest areas of central Kalimantan, Indonesia  

Microsoft Academic Search

The effect of logging practices on rainfall interception loss has been investigated in a humid tropical rainforest of central Kalimantan. The traditional volume balance method was used to measure throughfall, stemflow and interception loss. The evaporation rate during and after rainfall has ceased in canopy-saturated conditions was calculated by an energy balance method, which relied on the modified Penman equation

Chay Asdak; Paul G Jarvis; Paul V Gardingen

1998-01-01

400

Pleistocene climatic history of East and Central Asia based on paleopedological indicators in loess–paleosol sequences  

Microsoft Academic Search

A micromorphological comparison of the loess–paleosol sequence of the Karamaydan section, Central Asia, with the upper part of the Luochuan section, China, clearly indicates that for the Brunhes chron the sequence at Karamaydan is more detailed than the corresponding section at Luochuan. Single paleosols at Luochuan correspond to pedocomplexes at Karamaydan; for example, S 3 at Luochuan corresponds to PK

A Bronger; R Winter; T Heinkele

1998-01-01

401

The performance of the ZEUS central tracking detector z-by-timing electronics in a transputer based data acquisition system  

Microsoft Academic Search

The Central Tracking Detector of the ZEUS experiment employs a time difference technique to measure the z coordinate of each hit. The method provides fast, three-dimensional space point measurements which are used as input to all levels of the ZEUS trigger. Such a tracking trigger is essential in order to discriminate against events with vertices lying outside the nominal electron-proton

B. Foster; G. P. Heath; T. J. Llewellyn; D. M. Gingrich; N. Harnew; P. M. Hallam-Baker; T. Khatri; I. C. McArthur; P. Morawitz; J. Nash; P. D. Shield; S. Topp-Jorgensen; F. F. Wilson; D. B. Allen; R. C. Carter; M. D. Jeffs; M. C. Morrissey; S. P. H. Quinton; M. Postranecky

1993-01-01

402