Note: This page contains sample records for the topic cuarto molar supernumerario from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

Further analyses of Rio Cuarto impact glass  

NASA Technical Reports Server (NTRS)

Initial analyses of the geologic setting, petrology, and geochemistry of glasses recovered from within and around the elongate Rio Cuarto (RC) craters in Argentina focused on selected samples in order to document the general similarity with impactites around other terrestrial impact craters and to establish their origin. Continued analysis has surveyed the diversity in compositions for a range of samples, examined further evidence for temperature and pressure history, and compared the results with experimentally fused loess from oblique hypervelocity impacts. These new results not only firmly establish their impact origin but provide new insight on the impact process.

Schultz, Peter H.; Bunch, T. E.; Koeberl, C.; Collins, W.

1993-01-01

2

Taurodontism in deciduous molars.  

PubMed

Taurodont teeth are characterised by large pulp chambers at the expense of roots. An enlarged pulp chamber, apical displacement of the pulpal floor and no constriction at the level of the cement-enamel junction are the characteristic features of taurodont tooth. It appears more frequently as an isolated anomaly but its association with syndromes and other abnormalities have also been reported. Permanent dentition is more commonly affected than deciduous dentition. This paper presents a case report of taurodontism in relation to mandibular deciduous second molars. PMID:23737594

Bafna, Yash; Kambalimath, H V; Khandelwal, Vishal; Nayak, Prathibha

2013-01-01

3

[Acute infectious gastroenteritis in Rio Cuarto: clinic, diagnosis and epidemiology with special reference to viral infections].  

PubMed

The objectives of the present study are to describe the clinics view of acute infectious gastroenteritis (GE) at the community, in primary and secondary attention health centers, with special references to viral aetiology (VIGE); to correlate with drinkable water and excrete treatment; to develop for the first time a fast diagnostic using electron microscopy in Río Cuarto, Córdoba, Argentina, considering the university and community collaboration in the viral diagnostic. It has been during one year, 122 cases of acute GE, over its clinics epidemiology and diagnostic aspects (1999-2000). With conventional laboratory methods, it has been determined the bacteria and micotic aetiology (NOVIGE); the virology diagnostic with electron microscopy; and the use of the statistics for the data analysis. The microbial findings has been: pathogenics bacteria (31.7%), fungus (17%), parasites (1.2%), rotavirus (16.4%), calicivirus (1.6%), adenovirus and coronavirus (1.6%). The clinics findings are presents like digestive and extra-digestive signs, separated in NOVIGE (and no-diagnosticated) and VIGE groups. The seasonal viral and no-viral distributions are present in fig. 5. There are statistics signification: the NOVIGE in summer period (49%) against the VIGE (12.5%) (p < 0.0003); the VIGE in winter period (87.5%) against the VIGE in summer period (12.5%) (p < 0.0003); the GE aetiology (VIGE and NOVIGE) in associated with age groups (p < 0.0003); the vomits preceding diarrhoea in VIGE was 58% and in NOVIGE (19.5%) (P < 0.001). It has been presented without significative differences all the clinics signs and laboratory examinations; the breeding signs for the younger 2 years group compared with the 2 years older; the age correlation (< and > 2 years) and season (winter-summer) with the 16% for the first in VIGE (62.5% rotavirus); the absence of health systems at the NOVIGE (70%) and with both (29%); and others epidemiology considerations of the sequence. With came to conclusion that in our city: 1. there are VIGE with signficative participation of rotavirus; 2. its distribution are winter and age group, also considering the other age groups and virosis; 3. the NOVIGE may difference at the clinic sign like vomit, between all the possible sintomatology; 4. the principal cause of diarrhoea and the no seasonal distribution are the NOVIGE; 5. there are not a strong relationship of diarrhoea by shortage environmental health in this study; 6. it's possible in Río Cuarto to made a fast and direct virology diagnostic using an electron microscopy. PMID:12934244

Soñez, Carlos A; Mugnaini, María T; Godino, Sergio; Soñez, María V; Sánchez, Oscar; Fernández, Sol

2002-01-01

4

Geosphere-Biosphere Interactions in Bio-Activity Volcanic Lakes: Evidences from Hule and R?o Cuarto (Costa Rica)  

PubMed Central

Hule and Río Cuarto are maar lakes located 11 and 18 km N of Poás volcano along a 27 km long fracture zone, in the Central Volcanic Range of Costa Rica. Both lakes are characterized by a stable thermic and chemical stratification and recently they were affected by fish killing events likely related to the uprising of deep anoxic waters to the surface caused by rollover phenomena. The vertical profiles of temperature, pH, redox potential, chemical and isotopic compositions of water and dissolved gases, as well as prokaryotic diversity estimated by DNA fingerprinting and massive 16S rRNA pyrosequencing along the water column of the two lakes, have highlighted that different bio-geochemical processes occur in these meromictic lakes. Although the two lakes host different bacterial and archaeal phylogenetic groups, water and gas chemistry in both lakes is controlled by the same prokaryotic functions, especially regarding the CO2-CH4 cycle. Addition of hydrothermal CO2 through the bottom of the lakes plays a fundamental priming role in developing a stable water stratification and fuelling anoxic bacterial and archaeal populations. Methanogens and methane oxidizers as well as autotrophic and heterotrophic aerobic bacteria responsible of organic carbon recycling resulted to be stratified with depth and strictly related to the chemical-physical conditions and availability of free oxygen, affecting both the CO2 and CH4 chemical concentrations and their isotopic compositions along the water column. Hule and Río Cuarto lakes were demonstrated to contain a CO2 (CH4, N2)-rich gas reservoir mainly controlled by the interactions occurring between geosphere and biosphere. Thus, we introduced the term of bio-activity volcanic lakes to distinguish these lakes, which have analogues worldwide (e.g. Kivu: D.R.C.-Rwanda; Albano, Monticchio and Averno: Italy; Pavin: France) from volcanic lakes only characterized by geogenic CO2 reservoir such as Nyos and Monoun (Cameroon).

Cabassi, Jacopo; Tassi, Franco; Mapelli, Francesca; Borin, Sara; Calabrese, Sergio; Rouwet, Dmitri; Chiodini, Giovanni; Marasco, Ramona; Chouaia, Bessem; Avino, Rosario; Vaselli, Orlando; Pecoraino, Giovannella; Capecchiacci, Francesco; Bicocchi, Gabriele; Caliro, Stefano; Ramirez, Carlos; Mora-Amador, Raul

2014-01-01

5

Molar distalization with the Herbst appliance  

Microsoft Academic Search

This article reviews the dental effects of the Herbst appliance as well as itslong-term effects on the dentition. The Herbst appliance exhibits a pronounced high-pull headgear effect on the maxillary molars. Without retention, the molars tend to return to their former anteroposterior positions after the removal of the appliance. These distal movements of the maxillary molars are favorable in Class

Meson Lai

2000-01-01

6

MB2 in maxillary second molar.  

PubMed

Occurrence of the second mesiobuccal canal (MB2) is a frequent finding. Literary reports have shown it to be found more in the cases of the maxillary first molar. However the maxillary second molars have also been found with this variation in a number of canals. This paper presents a case report on the occurrence of a second mesiobuccal canal or the MB2 in the maxillary second molar. PMID:17347545

Prakash, R; Bhargavi, N; Rajan, Jeyavel; Joseph, Reuben; Velmurugan, N; Kandaswamy, D

2007-01-01

7

Maxillary First Molar with Two Root Canals  

PubMed Central

Knowledge regarding the anatomic morphology of maxillary molars is absolutely essential for the success of endodontic treatment. The morphology of the permanent maxillary first molar has been reviewed extensively; however, the presence of two canals in a two-rooted maxillary first molar has rarely been reported in studies describing tooth and root canal anatomies. This case report presents a patient with a maxillary first molar with two roots and two root canals, who was referred to the Department of Endodontics, Tabriz University of Medical Sciences, Iran.

Rahimi, Saeed; Ghasemi, Negin

2013-01-01

8

Molar ectopic pregnancy in the uterine cornus.  

PubMed

Cornual pregnancy is a rare form of ectopic pregnancy. The incidence of hydatiform molar pregnancy is 1 in 1000 to 2000 pregnancies. Molar cornual ectopic pregnancy is extremely rare. A 41-year-old nulliparous woman was admitted via the emergency department because of vaginal bleeding for 2 weeks. Transvaginal sonography exhibited a heterogeneous hypoechoic shadow in the endometrium that suggested a hematometra including blood clots and tissue, and a multicystic echogenic mass, with flow at color Doppler ultrasonography, in the lateral wall of the uterus. A laparoscopic cornuostomy was performed. Pathologic analysis demonstrated placental tissue with features consistent with a partial molar pregnancy. Systemic methotrexate therapy was administered to treat the possible remnants of the molar pregnancy. Molar cornual ectopic pregnancy can be successfully treated with laparoscopic cornuostomy and systemic methotrexate therapy. PMID:20226416

Hwang, Jong Ha; Lee, Jae Kwan; Lee, Nak Woo; Lee, Kyu Wan

2010-01-01

9

Unilateral molar distalization with a modified slider.  

PubMed

Although there are numerous publications on bilateral non-compliance molar distalization appliances, there is limited information on problems such as asymmetrical unilateral Class II malocclusions. The aim of the present investigation was to examine the distalization of molars unilaterally in patients with a unilateral Class II molar relationship utilizing a Keles Slider, designed without a bite plane. Ten girls (mean age 13.94 +/- 2.13 years) and seven boys (mean age 13.12 +/- 1.51 years) comprised the study material. Following insertion of the appliance, the patients were seen monthly and the screw was reactivated every 2 months. After a super-Class I molar relationship was achieved, the appliance was removed and the molars were stabilized with a Nance appliance for 2 months before the second-phase of orthodontic treatment. The Nance appliance was maintained in the palate until the end of canine distalization. Lateral cephalometric radiographs were obtained before and immediately after insertion of the molar distalizer. The results showed that the maxillary first molars were distalized bodily on average by 2.85 mm. The maxillary first premolars moved forward bodily 2 mm and were extruded 2.03 mm. In all, 1.32 mm of protrusion, 1.12 mm of extrusion, and 1.79 degrees of proclination of the upper incisors were observed. The mandibular incisors and mandibular molars erupted 0.83 and 0.95 mm, respectively. The unilateral Keles Slider distalized molars successfully to a Class I molar relationship. PMID:16648210

Sayinsu, Korkmaz; Isik, Fulya; Allaf, Ferdi; Arun, Tülin

2006-08-01

10

Third molar eruption among rural Nigerians.  

PubMed

Times of eruption of third molars were studied in rural Nigerian adolescents--125 males and 133 females. Results of this study showed that the average age for the initial eruption of third molars was 15 years in male subjects and 13 years for female subjects. The incidence of eruption showed a steep rise after the age of 16 years for male subjects and 14 years for female subjects. By the age of 19 years, all third molars had erupted into the oral cavity. The eruption of lower third molars was generally ahead of the upper third molars for all age groups. The results of this study suggest that (1) the timing of third molar eruption is strongly influenced by the availability of mandibular trigone space, (2) the attrition and shrinkage of the dental arch, probably as the result of nonrefined highly fibrous diets, produce larger mandibular trigone spaces, and (3) the early eruption of third molars observed in the present study may be due to the nature of the diet used and the vigorous employment of the masticatory apparatus (from infancy) by the subjects examined. PMID:2003009

Odusanya, S A; Abayomi, I O

1991-02-01

11

Unilateral molar distalization: a nonextraction therapy.  

PubMed

In the recent years, nonextraction treatment approaches and noncompliance therapies have become more popular in the correction of space discrepancies. One of the conventional approaches for space gaining in the arches without patient compliance is done by using certain extra oral appliances or intraoral appliance. The greatest advantage of certain appliances like fixed functional and molar distalization appliances is that they minimize the dependence on patient cooperation. Molar distalization appliances like pendulum appliance which distalizes the molar rapidly without the need of head gear can be used in patients as a unilateral space gaining procedure due to buccal segment crowding. PMID:23320203

Prasad, M Bhanu; Sreevalli, S

2012-01-01

12

Unilateral Molar Distalization: A Nonextraction Therapy  

PubMed Central

In the recent years, nonextraction treatment approaches and noncompliance therapies have become more popular in the correction of space discrepancies. One of the conventional approaches for space gaining in the arches without patient compliance is done by using certain extra oral appliances or intraoral appliance. The greatest advantage of certain appliances like fixed functional and molar distalization appliances is that they minimize the dependence on patient cooperation. Molar distalization appliances like pendulum appliance which distalizes the molar rapidly without the need of head gear can be used in patients as a unilateral space gaining procedure due to buccal segment crowding.

Prasad, M. Bhanu; Sreevalli, S.

2012-01-01

13

Efficiency of molar distalization with the XBow appliance related to second molar eruption stage.  

PubMed

To quantitatively evaluate on lateral cephalograms horizontal, vertical, and angular changes in the position of the maxillary first molar based on the presence and absence of erupted maxillary second molars when it is distalized with the XBow appliance. In this retrospective study, a total of 102 consecutively treated cases were assessed. Lateral cephalograms were obtained at the start and after completion of active treatment with the XBow appliance. In one group of patients, distal movement of the maxillary first molars was performed before the eruption of maxillary second molars; in the other group of patients, both first and second maxillary molars were simultaneously moved distally. All cephalograms were superimposed on palatal plane using the method of best-fit. In order to compare the mean horizontal, vertical, and angular changes in molar position between the treatment groups and gender, a multivariate analysis of covariance (MANCOVA) was performed with the pre-treatment class II severity used as a covariate. Regression analysis was also performed to further explore any possible relationships between the predictor variables and the quantity and quality of distalization. A MANCOVA revealed that the eruption stage of the maxillary second molar did not have a significant effect on the change in position of the maxillary first molar after treatment with a XBow appliance. When distalizing maxillary first molars with a XBow appliance, there is no difference in the amount of distalization in patients with erupted and unerupted maxillary second molars. PMID:23172578

Flores-Mir, Carlos; McGrath, L M; Heo, G; Major, P W

2013-12-01

14

Fabrication and Evaluation of a Noncompliant Molar Distalizing Appliance: Bonded Molar Distalizer  

PubMed Central

Objective Attempts to treat class II malocclusions without extraction in non-compliant patients have led to utilization of intraoral molar distalizing appliances. The purpose of this study was to investigate dental and skeletal effects of Bonded Molar Distalizer (BMD) which is a simple molar distalizing appliance. Materials and Methods Sixteen patients (12 girls, four boys) with bilateral half-cusp class II molar relationship, erupted permanent second molars and normal or vertical growth pattern were selected for bilateral distalization of maxillary molars via BMD. The screws were activated every other day, alternately. Lateral cephalograms and study models were obtained before treatment and after 11 weeks activation of the appliance. Results Significant amounts of molar distalization, molar distal tipping and anchorage loss were observed. The mean maxillary first molar distal movement was 1.22±0.936 mm with a distal tipping of 2.97±3.74 degrees in 11 weeks. The rate of distal movement was 0.48 mm per month. Reciprocal mesial movement of the first premolars was 2.26±1.12 mm with a mesial tipping of 4.25±3.12 degrees. Maxillary incisors moved 3.55±1.46 mm and tipped 9.87±5.03 degrees mesially. Lower anterior face height (LAFH) decreased 1.28±1.36 mm. Conclusion BMD is appropriate for distalizing maxillary molars, especially in patients with critical LAFH, although significant amounts of anchorage loss occur using this appliance.

Sodagar, A.; Ahmad Akhoundi, M. S.; Rafighii, A.; Arab, S.

2011-01-01

15

Maintaining perspective on third molar extraction.  

PubMed

Third molar extraction is one of the most common oral surgeries performed on Canadian patients, particularly young adults. Vigorous debate persists about the risks of retention of asymptomatic impacted third molars, compared to extraction. The controversy centres on whether medical necessity justifies the cost of third molar extraction for the patient in terms of substantial pain and potential loss of income during recovery and for the federal or provincial health care systems, which may be billed for a portion of the surgical fees. Several research studies initiated by the American Association of Oral and Maxillofacial Surgeons (AAOMS) report new associations between oral disease and asymptomatic impacted third molars. These findings merit careful attention because they are being used by the AAOMS to advocate for prophylactic third molar extraction-an approach that contradicts the conclusions of a Canadian health technology report, American Public Health Association policy, and health technology reports from Sweden, Belgium and the UK. The decision to extract third molars seems most effective when made on a case-by-case basis that is tailored to each patient's health status and access to professional oral health care. PMID:24309037

Boughner, Julia C

2013-09-01

16

A new approach in maxillary molar distalization: Intraoral bodily molar distalizer  

Microsoft Academic Search

The objectives of our study were to achieve bodily molar distalization, avoid distal tipping of molars, eliminate the need for patient cooperation (no headgear, no elastics, and no esthetic and social concern), and finally to minimize the treatment period and maximize the treatment efficiency. The study was carried out on 5 males and 10 females, a total of 15 patients.

Ahmet Keles; Korkmaz Sayinsu

2000-01-01

17

Ectopic molar pregnancy: a case report  

PubMed Central

The incidence of hydatidiform moles is 1 per 1,000 pregnancies. Ectopic pregnancy occurs in 20 per 1,000 pregnancies. Thus, the incidence of the ectopic molar gestation is very rare. We report a case of tubal molar pregnancy diagnosed at the systematic histology exam of an ectopic pregnancy. We report the case of 32 years old nulliparus women who presented a vaginal bleeding, lower abdominal pain and 6 weeks amenorrhea corresponding to the last menstrual period. At the clinical examination, the arterial pressure was 100/60 mmHG. The gynecological examination was difficult because of lower abdominal pain. Serum gonadotropin activity was 3454 ui/l. Pelvic ultrasound revealed an irregular echogenic mass in the left adnexa. Diagnostic laparoscopy revealed a left-sided unruptured ampullary ectopic pregnancy. A left laparoscopic salpingectomy was performed. The systematic histologic test identified an ectopic partial molar pregnancy, which was confirmed by DNA ploidy image analysis. The patient was followed with weekly quantitative B-hCG titers until three successive B-hCG levels were negative. It is pertinent that clinicians take routine histological examination of tubal specimens in ectopic pregnancy very seriously in order to diagnose cases of ectopic molar gestations early and mount appropriate post treatment surveillance.

Bousfiha, Najoua; Erarhay, Sanaa; Louba, Adnane; Saadi, Hanan; Bouchikhi, Chahrazad; Banani, Abdelaziz; Fatemi, Hind El; Sekkal, Med; Laamarti, Afaf

2012-01-01

18

Clostridium perfringens sepsis following a molar pregnancy.  

PubMed

Clostridium perfringens sepsis is rare since the legalization of abortion in 1973. This is a 49 year old female who developed clostridial sepsis after suction dilation and curettage for a molar pregnancy. A hysterectomy was performed after prompt recognition, and the patient survived. PMID:24096275

Adams, Brandi N; Lekovic, Jovana P; Robinson, Suzzette

2014-01-01

19

Ectopic molar pregnancy: a case report.  

PubMed

The incidence of hydatidiform moles is 1 per 1,000 pregnancies. Ectopic pregnancy occurs in 20 per 1,000 pregnancies. Thus, the incidence of the ectopic molar gestation is very rare. We report a case of tubal molar pregnancy diagnosed at the systematic histology exam of an ectopic pregnancy. We report the case of 32 years old nulliparus women who presented a vaginal bleeding, lower abdominal pain and 6 weeks amenorrhea corresponding to the last menstrual period. At the clinical examination, the arterial pressure was 100/60 mmHG. The gynecological examination was difficult because of lower abdominal pain. Serum gonadotropin activity was 3454 ui/l. Pelvic ultrasound revealed an irregular echogenic mass in the left adnexa. Diagnostic laparoscopy revealed a left-sided unruptured ampullary ectopic pregnancy. A left laparoscopic salpingectomy was performed. The systematic histologic test identified an ectopic partial molar pregnancy, which was confirmed by DNA ploidy image analysis. The patient was followed with weekly quantitative B-hCG titers until three successive B-hCG levels were negative. It is pertinent that clinicians take routine histological examination of tubal specimens in ectopic pregnancy very seriously in order to diagnose cases of ectopic molar gestations early and mount appropriate post treatment surveillance. PMID:22655097

Bousfiha, Najoua; Erarhay, Sanaa; Louba, Adnane; Saadi, Hanan; Bouchikhi, Chahrazad; Banani, Abdelaziz; El Fatemi, Hind; Sekkal, Med; Laamarti, Afaf

2012-01-01

20

Cell ploidy in molar placental disease.  

PubMed

Molar diseases of the placenta is associated with cystic change in the villi. The cysts may be from 5-20+ mm in diameter. This disease has been described in association with triploid and diploid cell lines and with and without an accompanying embryo or fetus. It may be followed by malignant change and invasive chorio-carcinoma. In order to investigate the association between cell ploidy, embryonic development and subsequent malignancy, a detailed study of 30 conceptuses with molar disease was made, with the accompanying maternal history and follow-up. The cell ploidy was determined by measurement of nuclei by a cytoscan light microscope connected to a computer program as has been previously described. Diploid cell lines were not found with embryonic or fetal development. Triploid cell lines were always associated with an embryo or fetus. Triploidy is not associated with hyperplastic changes in the trophoblast. These results are presented and discussed. PMID:715729

Poland, B J; Baillie, D L

1978-10-01

21

Mineral trioxide aggregate in primary molar pulpotomies  

Microsoft Academic Search

DesignQuasi-randomised controlled trial.InterventionPrimary molar teeth were treated using a conventional pulpotomy technique but received either mineral trioxide aggregate (MTA, test group) or formocresol (FC, control group) as a pulp dressing. Follow-up clinical (not blind) and radiographic (blind) assessments were undertaken every 6 months.Outcome measureTime elapsed between treatment and either 1) detection of pulpotomy failure 2) natural exfoliation of tooth 3)

Monty Duggal; Mohammed Al Ansary

2006-01-01

22

An analysis of molar tooth form  

Microsoft Academic Search

The maxillary first permanent molars of different human population samples were compared by multivariate analysis of two-dimensional coordinates of datum points defining the occlusal surface and periphery of the crown. This technique proved that discrimination was possible between teeth which could not be discriminated visually or by analysis of the mesio-distal or buccolingual diameters.Copyright © 1978 S. Karger AG, Basel

C. L. B. Lavelle

1978-01-01

23

Etiological factors in second mandibular molar impaction  

PubMed Central

Objectives: The impaction of the second mandibular molar (MM2) has recently become more prevalent. Several etiological hypothesis have been proposed to investigate the association between skeletal features and impaction of MM2. The aims of this study were to analyze the skeletal features in patients with MM2 impaction and the association between arrested eruption of MM2 and the presence of the third mandibular molar (MM3). Study Design: In this retrospective study 48 subjects from 3,530 Caucasian orthodontic patients with MM2 impaction were included in a study group (SG) and compared to a control group (CG) of 200 subjects without MM2 impaction. Panoramic radiographs evaluated the presence or absence of the MM3 germ. Cephalometric analysis was performed to evaluate linear and angular skeletal values. For the statistical analysis, descriptive statistics, Student’s t-test, ?2 test and odds ratio (OR) were used. Results: The paired comparisons between SG and CG showed in cephalometric analysis both a reduced mandibular gonial angle (ArGoMe) and lowered Jarabak’s polygon value with a statistically significant difference (P? 0.05). MM3 was statistically significant associated (P? 0.05) with MM2 impaction but it is not a risk factor (OR 0.817). Conclusions: Subjects with MM2 impaction show a vertical condylar growth direction. MM3 is not a risk factor for MM2 impaction. Key words:Impacted mandibular second molar, skeletal features, orthodontic.

Altieri, Federica; Calasso, Sabrina

2014-01-01

24

Third Molars and Acute Pericoronitis: A Military Problem.  

National Technical Information Service (NTIS)

Acute pericoronitis is a debilitating disease that primarily afflicts the soft and bony tissues of third molars in young adults. The positional characteristics of the third molars and the prevalence of acute pericoronitis at the time of entry is described...

S. A. Leone M. J. Edenfield

1987-01-01

25

Molar Tooth Diversity, Disparity, and Ecology in Cenozoic Ungulate Radiations  

Microsoft Academic Search

A classic example of adaptive radiation is the diversification of Cenozoic ungulates into herbivore adaptive zones. Their taxonomic diversification has been associated with changes in molar tooth morphology. Analysis of molar crown types of the Artiodactyla, Perissodactyla, and archaic ungulates (\\

Jukka Jernvall; John P. Hunter; Mikael Fortelius

1996-01-01

26

Distal molar movement with Kloehn headgear: Is it stable?  

Microsoft Academic Search

The aim of this study was to evaluate intramaxillary molar movement after 8 months of cervical traction and posttreatment displacement 7 years later. The total molar displacements in relation to stable intraosseous reference points were compared with those observed in an untreated control group that also had intraosseous reference indicators inserted. During the headgear period, the type of molar displacement

Birte Melsen; Michel Dalstra

2003-01-01

27

Attachment Levels and Crevicular Depths at the Distal of Mandibular Second Molars Following Removal of Adjacent Third Molars.  

National Technical Information Service (NTIS)

The effect of root planing and curettage on the crevicular depth and periodontal attachment at the distal of mandibular second molars following removal of adjacent impacted or partially erupted third molars was evaluated in eighteen patients between the a...

W. H. Osborne A. J. Snyder T. R. Tempel

1981-01-01

28

Natal primary molar: clinical and histological aspects.  

PubMed

The authors report a case of natal primary molar in a healthy 14-day-old child. The diagnosis of the case and the treatment plan are discussed, as well as histological analyses of the natal tooth. The tooth presented an immature appearance, with high mobility and insertion only in soft tissue, and therefore the clinical option adopted was dental extraction. Histological analyses revealed enamel hypoplasia and dentin showing a typical tubular pattern without alterations. The soft tissue had young and richly vascularized pulp with areas of chronic inflammatory infiltration. PMID:20587958

Ruschel, Henrique C; Spiguel, Monica H; Piccinini, Daniela D; Ferreira, Simone H; Feldens, Eliane G

2010-06-01

29

Topographic study of root trunk type on Chinese molars with Class III furcation involvements: molar type and furcation site.  

PubMed

This study investigated the relationship between root trunk length and prognosis for molars with furcation involvement. Molars with furcation involvement were obtained from 169 patients affected with periodontitis. The test group consisted of 174 hopeless molars screened from a total of 441 molars with Class III involvement; the remaining 267 molars formed the control group. Both arches showed a significantly higher missing rate for teeth with a long root trunk length (type C) in second molars (41.3% and 32.4% in the maxilla and mandible, respectively), with a high degree of Class III furcation involvement for the test group (extracted hopeless or poor prognosis), compared to first molars (9.9% and 0.9% in the maxilla and mandible, respectively). Both arches had a significantly higher prevalence of long root trunk lengths in the second molars compared to first molars, irrespective of furcation site. Although first molars had an early and higher prevalence of Class III furcation involvement than second molars, the latter reached a significantly higher missing rate. Molars with longer root trunk lengths had a higher risk for poor prognosis than shorter root trunks when teeth were affected by Class III furcation involvement. For extracted furcation-involved maxillary second molars that failed to respond to periodontal therapy, long root trunk length (C) accounted for the greatest prevalence at the mesial furcation site (41.8%), followed by the distal (33.0%) and buccal sites (25.2%); the greatest prevalence of root trunk length C was found at the lingual (47.9%) and buccal furcation sites (45.1%) of mandibular second molars. When a molar with root trunk type C has a Class III involvement, the prognosis is poor; for the disease to reach that level, greater amounts of attachment must be destroyed. PMID:15839594

Hou, Guey-Lin; Hung, Chun-Cheng; Tsai, Chi-Cheng; Weisgold, Amold S

2005-04-01

30

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

31

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

32

Clinical significance of computed tomography assessment for third molar surgery  

PubMed Central

Surgical extraction of the third molar is the most commonly performed surgical procedure in the clinical practice of oral surgery. Third molar surgery is warranted when there is inadequate space for eruption, malpositioning, or risk for cyst or odontogenic tumor formation. Preoperative assessment should include a detailed morphologic analysis of the third molar and its relationship to adjacent structures and surrounding tissues. Due to developments in medical engineering technology, computed tomography (CT) now plays a critical role in providing the clear images required for adequate assessment prior to third molar surgery. Removal of the maxillary third molar is associated with a risk for maxillary sinus perforation, whereas removal of the mandibular third molar can put patients at risk for a neurosensory deficit from damage to the lingual nerve or inferior alveolar nerve. Multiple factors, including demographic, anatomic, and treatment-related factors, influence the incidence of nerve injury during or following removal of the third molar. CT assessment of the third molar prior to surgery can identify some of these risk factors, such as the absence of cortication between the mandibular third molar and the inferior alveolar canal, prior to surgery to reduce the risk for nerve damage. This topic highlight presents an overview of the clinical significance of CT assessment in third molar surgery.

Nakamori, Kenji; Tomihara, Kei; Noguchi, Makoto

2014-01-01

33

Lower dental arch changes after bilateral third molar removal.  

PubMed

OBJECTIVE. To evaluate the changes in lower dental arch after bilateral lower third molars removal. MATERIAL AND METHODS. The study group consisted of 30 non-orthodontic patients (mean age 25,5 years, refered for bilateral lower third molars removal. Orthopantomograms and dental casts were made before and 6-8 months after surgical removal of lower third molars. Transversal lower arch widths between lower canines and second premolars and lower arch total tooth size-arch lenght discrepancy were evaluated on dental casts. The angulation of lower second premolars, first and second molars was measured in horizontal and mandibular planes on orthopantomograms. RESULTS. No significant difference of inter-canine and inter-premolar transversal width was noticed. No significant changes were observed in total tooth-size lenght discrepancy, except in S1 segment consisted of first and second premolar and the canine on the right quadrant of the lower dental arch. The angulation of second premolars and first molars did not show any significant changes, however there were statistically significant changes between angulation of lower second molars on both sides. CONCLUSIONS. After bilateral removal of lower third molars, lower second molars awhile showed a tendency to move backwards, but no obvious relationship between the third molar and anterior crowding was observed. Whereas the observation time is short and the patient's age is young and it can not be concluded that lower third molars cause the changes in the dental arch. PMID:24824058

Stanaityt?, R?ta; Trakinien?, Giedr?; Gervickas, Albinas

2014-01-01

34

A simplified approach to true molar intrusion  

PubMed Central

Background Orthodontic management of anterior open bites is a demanding task for orthodontists. Molar intrusion as a primary means of open bite correction entails the need for appropriate anchorage. Orthodontic mini implants can provide the required mechanical support. The suggested procedure aims to reduce the risk of complications such as root damage or soft tissue irritations while minimizing overall complexity. Methods Three female patients aged 14, 18 and 19 years who decided against a surgical correction were treated with a device consisting of mini implants in the palatal slope, a palatal bar and intrusion cantilevers. Results In all three patients, an open bite reduction of more than a millimeter occurred within four months. An anterior overbite of 2 mm or more could be established within 6 to 9 months. Conclusions The method presented in this article enables the practitioner to use mini implants in an easily accessible insertion site. A lab-side procedure is optional but not required.

2012-01-01

35

Molar extinction coefficients of some fatty acids  

NASA Astrophysics Data System (ADS)

The attenuation of gamma rays in some fatty acids, viz. formic acid (CH 2O 2), acetic acid (C 2H 4O 2), propionic acid (C 3H 6O 2), butyric acid (C 4H 8O 2), n-hexanoic acid (C 6H 12O 2), n-caprylic acid (C 8H 16O 2), lauric acid (C 12H 24O 2), myristic acid (C 14H 28O 2), palmitic acid (C 16H 32O 2), oleic acid (C 18H 34O 2) and stearic acid (C 18H 36O 2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good agreement between experiment and theory.

Sandhu, G. K.; Singh, Kulwant; Lark, B. S.; Gerward, L.

2002-10-01

36

Nerve damage and third molar removal.  

PubMed

The surgical removal of lower third molars endangers both the lingual and inferior alveolar nerves. Patients sustaining an injury to either of these nerves must be managed correctly, and this requires a diagnosis of the injury type and regular monitoring of the recovery of sensation. Surgical intervention for a damaged inferior alveolar nerve is not usually indicated but may be undertaken: if the nerve is completely divided and the severed ends are misaligned; if a bony fragment has compressed the mandibular canal; or if the patient suffers from persistent neuropathic pain. In contrast, after injury to the lingual nerve, if sensory testing demonstrates no neural recovery within 3-4 months, exploration of the injury site and microsurgical repair of the damaged nerve is indicated. PMID:14558203

Loescher, A R; Smith, K G; Robinson, P P

2003-09-01

37

Third molar surgery in general dental practice.  

PubMed

A survey to determine the treatment procedures adopted by general dental practitioners for the removal of impacted third molar teeth was undertaken. Questionnaires were mailed to a sample of 100 practising dentists. Of the 67 per cent that responded, 41.8 per cent (28) indicated that they would attempt the procedure while the remaining 51.2 per cent (39) would not do so. Neither the length of professional experience nor whether they practised in metropolitan or country areas had a bearing on whether the impacted tooth would be removed or not. In general, South African general dental practitioners routinely removed overlying bone by means of a bur, sutured the mucosal incision wound, prescribed antibiotics, analgesics and a mouthwash, and recalled their patients for a post-operative review. Steroids were not prescribed. PMID:9461920

Naidoo, L C

1997-02-01

38

Congenitally missing maxillary first permanent molars: a case report.  

PubMed

Congenitally absent maxillary first permanent molars is a rare clinical finding. It usually occurs with severe oligodontia in association with other abnormalities of the integumentary system. This article presents the case of bilateral absent maxillary permanent molars with severe oligodontia and no other abnormalities. PMID:2369704

Lapeer, G L

1990-06-01

39

Growth and Calcification in the Prenatal Human Primary Molars  

Microsoft Academic Search

SYNOPSIS IN INTERLINGUA CRESCENTIA E CALCIFICATION IN LE PRENATAL MOLARES PRIMARI HUMAN.—Con le objectivo de studiar statisticamente le relation inter le crescentia e le calcification, le 4 germines de molares primari in 69 fetos human del gruppo de etate circumnatal esseva dissecate e tincturate con rubio alizarinic S. Le grado del calcification e le dimension microscopic del corona esseva determinate.

John W. Coughlin; Gordon J. Christensen

1966-01-01

40

Patients' Retrospective Preference for Extraction of Asymptomatic Third Molars.  

National Technical Information Service (NTIS)

The purpose of this study was to determine the personal utility of asymptomatic third molar removal in military patients. From 1 to 30 days (mean=7.4) after the extraction of one or more third molars, 100 returning patients (all male, mean age=20.1) were ...

J. S. Arthur J. W. Rodden M. E. Cohen

1990-01-01

41

Mandibular First Molar with a Single Root and Single Canal  

PubMed Central

Successful endodontic management of mandibular first molar with a single root and single canal is diagnosed with the aid of dental operating microscope and multiple angled radiographs. In addition all the mandibular molars and premolars were single rooted on either side.

Sooriaprakas, Chandrasekaran; Ballal, Suma; Velmurugan, Natanasabapathy

2014-01-01

42

Mandibular first molar with a single root and single canal.  

PubMed

Successful endodontic management of mandibular first molar with a single root and single canal is diagnosed with the aid of dental operating microscope and multiple angled radiographs. In addition all the mandibular molars and premolars were single rooted on either side. PMID:24715990

Sooriaprakas, Chandrasekaran; Ballal, Suma; Velmurugan, Natanasabapathy

2014-01-01

43

Hydrophobic effects on partial molar volume  

NASA Astrophysics Data System (ADS)

The hydrophobic effects on partial molar volume (PMV) are investigated as a PMV change in the transfer of a benzenelike nonpolar solute from the nonpolar solvent to water, using an integral equation theory of liquids. The volume change is divided into two effects. One is the ``packing'' effect in the transfer from the nonpolar solvent to hypothetical ``nonpolar water'' without hydrogen bonding networks. The other is the ``iceberg'' effect in the transfer from nonpolar water to water. The results indicate that the packing effect is negative and a half compensated by the positive iceberg effect. The packing effect is explained by the difference in the solvent compressibility. Further investigation shows that the sign and magnitude of the volume change depend on the solute size and the solvent compressibility. The finding gives a significant implication that the exposure of a hydrophobic residue caused by protein denaturation can either increase or decrease the PMV of protein depending on the size of the residue and the fluctuation of its surroundings.

Imai, Takashi; Hirata, Fumio

2005-03-01

44

Prosthetic rehabilitation of a hemisected maxillary molar: a rare entity.  

PubMed

Gingival recession beyond grade III and grade IV level involving furcation defects can lead to tooth loss if not intervened at appropriate time. The treatment options include scaling and root planing, Furcation-plasty, Tunnel preparation, Root separation and resection. The chief complaint of the patient was pain in the upper left first molar because of grade III furcation involvement. Since it was a four rooted molar, the treatment of choice was hemisection of the tooth and extraction of the distal half following endodontic treatment. As the second molar was mesially tilted the prosthodontic rehabilitation was done with a hybrid prosthesis involving a full coverage conventional porcelain fused to metal retainer on the hemisected molar and a resin bonded partial coverage retainer on the tilted second molar. The resultant prosthesis is termed as "Hybrid prosthesis". PMID:24431763

Yadav, Preeti; Tahir, Mohammed; Kumar, M V Sunil; Rao, Harikesh

2013-09-01

45

Infections in elderly patients associated with impacted third molars.  

PubMed

The objective of this study was to determine the clinical characteristics of infections caused by impacted third molars in elderly persons. Infectious disorders (26 pericoronitis, 8 secondarily infected dentigerous cysts, 4 perimandibular abscesses with limited osteomyelitis, 2 chronic mandibular osteomyelitis, and 1 odontogenic skin fistula) associated with the impacted third molars impacted third molars were clinically investigated in 41 patients over 60 years of age. Twenty-nine causative teeth were located in the mandibular angle and nine in the ramus; the three remaining lesions (two cysts one pericoronitis) were associated with the maxillary third molar. Bone resorption was noted in most patients, and this caused the originally embedded tooth to become exposed intraorally. It was concluded that oral infection in elder persons are occasionally caused by retained impacted third molars with overlapping of other factors. PMID:7614172

Osaki, T; Nomura, Y; Hirota, J; Yoneda, K

1995-02-01

46

Human third molars development: Comparison of 9 country specific populations.  

PubMed

The majority of age estimation models based on third molar development are constructed on samples from populations with described and outlined origin. Due to unlike research protocols these studies can rarely be compared for the evaluation of possible geographical or ethnical influences on third molar development. The aim of this study is to evaluate country specific third molar development on standardized collected and analyzed data. On panoramic radiographs selected from subjects out of 9 country specific populations (Belgium, China, Japan, Korea, Poland, Thailand, Turkey, Saudi-Arabia and South-India) the four third molar scores were registered, according to a modified Gleiser and Hunt methodology. To obtain for each subject a (factor) score which represents the degree of third molar development, a generalized linear mixed model for multivariate ordinal data was fitted on the repeated third molar scores. Differences between countries are analyzed using gender-specific regression models for these factor scores with age and country as predictors. Comparisons between countries revealed differences in speed and onset of development. However, although reaching statistical significance, differences in actual value were small and not constant over the considered age range. In all countries, at all ages, males were ahead in third molar development compared to females. PMID:20570071

Thevissen, P W; Fieuws, S; Willems, G

2010-09-10

47

Maxillary molar distalization with a bone-anchored pendulum appliance.  

PubMed

To obtain an effective and compliance-free molar distalization without an anchorage loss, we designed the bone-anchored pendulum appliance (BAPA). The aim of this study was to evaluate the stability of the anchoring screw, distalization of the maxillary molars, and the movement of teeth anterior to maxillary first molars. The study group comprised 10 patients (mean age 13.5 +/- 1.8 years) with Class II molar relationship. A conventional pendulum appliance was modified to obtain anchorage from an intraosseous screw instead of the premolars. The screw was placed in the anterior paramedian region of the median palatal suture. Skeletal and dental changes were measured on cephalograms, and dental casts were obtained before and after distalization. A super Class I molar relationship was achieved in a mean period of 7.0 +/- 1.8 months. The maxillary first molars distalized an average of 6.4 +/- 1.3 mm in the region of the dental crown by tipping distally an average of 10.9 degrees +/- 2.8 degrees . Also, the maxillary second premolar and first premolar moved distally an average of 5.4 +/- 1.3 mm and 3.8 +/- 1.1 mm, respectively. The premolars tipped significantly distally. No anterior incisor movement was detected. The BAPA was found to be an effective, minimally invasive, and compliance-free intraoral distalization appliance for achieving both molar and premolar distalization without any anchorage loss. PMID:16808573

Kircelli, Beyza Hancio?lu; Pekta?, Zafer Ozgür; Kircelli, Cem

2006-07-01

48

Fifth alternative for replacement of maxillary first molar.  

PubMed

There are occasions when the patient is missing only one first molar or the first molar is slated for an odontectomy (extraction). Most of the time, there are only four common avenues for replacement: partial removable prosthesis, Maryland bridge, ceramic or ceramic to metal fixed prosthesis and osseo-integrated implant supported crown. In this article, the author discusses the least common avenue for replacement of missing maxillary first molar--an orthodontic closure. He discusses and demonstrates; Maximum, Medium and Minimum Anchorage strategies on acrylic models. Preserving the anchorage is necessary for successful execution of this orthodontic procedure. This demonstration is followed by presentation of the actual case. PMID:23941033

Palencar, Adrian J

2013-01-01

49

The impact of retained third molars on the deployed airman.  

PubMed

Dental emergencies can significantly affect the mission of the deployed unit. As many as 22% of all emergency department visits at a deployed Expeditionary Medical Support facility can be attributed to dental problems and many of these problems are caused by impacted third molar teeth. Currently, there is no reliable method of predicting when asymptomatic, partially erupted third molar teeth will become painful. Therefore, it is imperative that Air Force dental providers carefully consider the consequences of giving patients a clean bill of health when asymptomatic, partially erupted third molar teeth are present in the oral cavity. Recommendations for future study are presented. PMID:18277719

Langsten, Robert E; Dunn, William J

2008-01-01

50

Revascularization/Regeneration performed in immature molars: case reports.  

PubMed

These 3 case reports the outcome of revascularization treatment in necrotic immature molars. During treatment, a tri antibiotic mix was used to disinfect the pulp for 2 weeks. Then a blood clot was created in the canal, over which mineral trioxide aggregate was placed. After 24 months, the immature molars showed continuation of root development. The patients were asymptomatic, no sinus tracts were evident and apical periodontitis was resolved Results from these cases show that revascularization/regeneration using 3Mix-MP method could be effective for managing immature permanent molar teeth with pulpal necrosis. PMID:23855165

Sönmez, I S; Akbay Oba, A; Erkmen Almaz, M

2013-01-01

51

Molar heat capacity and entropy of calcium metal  

USGS Publications Warehouse

The heat capacity of calcium has been measured at 85 mean temperatures between T ??? 8 K and T ??? 369 K using an adiabatically-shielded calorimeter in an intermittent heating mode. At T = 298.15 K, the recommended values for the molar heat capacity, molar entropy, and molar enthalpy increment referred to T = 0 are (25.77 ?? 0.08) J??K-1??mol-1, (42.90 ?? 0.11) J??K-1??mol-1, and (5811 ?? 12) J??mol-1, respectively. The uncertainties are twice the standard deviation of the mean. ?? 1997 Academic Press Limited.

Hemingway, B. S.; Robie, R. A.; Chase, M. W.

1997-01-01

52

[Partial molar pregnancy. A case report and literature review].  

PubMed

We report the case of a 17 year old patient with partial molar pregnancy and coexistent live fetus of 13 gestational weeks diagnosed by ultrasound, which required the termination of pregnancy for maternal decompensation. PMID:21966838

Morales García, Víctor; Bautista Gómez, Esperanza; Vásquez Santiago, Edmundo; Santos Pérez, Ursula

2011-07-01

53

[Radiographic study of formation and calcification of the third molar].  

PubMed

A total of 500 orthopantomographic X-rays of Mexican children and teenagers of either sex, aged 7-18, were studied in order to ascertain the development and calcification stages of their third molars, as well as the most frequent anomalies related with them. It was observed that the dental bud appears between ages nine and eleven, and that the third molar is absent in 32.4% of the population, with a predominance of females over males. It was also found that 7.4% of molars evidenced malposition during their early stages of development. In view of such findings, the authors consider that a diagnosis of oligodontia and malposition of the third molar, cannot be established before age 13. PMID:2132460

Nuño González, M M; Llarena del Rosario, M E

1990-11-01

54

Molar extinction coefficient of fullerenes and related hydrogenated derivatives ``fulleranes''  

NASA Astrophysics Data System (ADS)

Fullerenes, the carbon molecules with 60 and 70 atoms, were recently detected in a series of planetary nebulae, in protoplanetary nebulae and in other astrophysical objects. The detection and the quantitative determination of these molecules was made possible by the measurement of their reference infrared spectra and the relative molar extinction coefficients and integrated molar absorptivity on laboratory scale. It is expected that also fulleranes the hydrogenated derivatives of C60 and C70 may be present in the same objects where fullerenes were detected. This prompted us to synthesize the hydrogenated fullerenes, to record their infrared spectra and the measure the molar extinction coefficients and integrated molar absorptivity on laboratory scale to have a reference in the search of these fullerene derivatives in space

Cataldo, Franco; Iglesias-Groth, Susana; Manchado, Arturo

2012-08-01

55

The Tucker technique: conservative molar inlays preserving the transverse ridge.  

PubMed

Conservation of healthy tooth structure should be the aim of any restorative procedure. Two inlays may be an ideal choice for the treatment of maxillary molars to preserve the transverse ridge and maintain structural integrity. PMID:21910585

Hess, T A; Wadhwani, C P K

2012-01-01

56

Characteristics of molar pregnancy in a 12 year old.  

PubMed Central

Gestational trophoblastic disease rarely is reported in early teens. This article describes a 12-year-old black female with molar disease, in which the characteristics and treatment are not dissimilar from adults.

Chapman, G. W.

1996-01-01

57

Determining Molar Combining Ratios Using Radioisotopes--A Student Experiment  

ERIC Educational Resources Information Center

Outlines an experimental procedure in which an iodine radioisotope is used to determine molar combining ratios of lead and silver with the iodine. Tables and graphs show the definitive results that should be attainable. (CP)

Sears, Jerry A.

1976-01-01

58

Mandibular First Molar with a Radix Entomolaris: An Endodontic Dilemma  

PubMed Central

It is known that the mandibular first molar can display significant anatomical variations namely the number of root canals, the number of roots and morphology. Mandibular molars may sometimes have an additional root located lingually (the radix entomolaris) or buccally (the radix paramolaris). If encountered, an awareness and understanding of this unusual root and its canal morphology can contribute to the successful outcome of root canal treatment. This case report discusses endodontic treatment of a mandibular first molar with a radix entomolaris, which is a rare entity and poses as an endodontic dilemma for the clinician with respect to diagnosis and subsequent treatment. Clinicians should be aware of these unusual root morphologies in the mandibular first molar which needs strategic treatment as unfilled canals remain a nidus for infection and can compromise treatment outcome.

Sarangi, Priyanka; Uppin, Veerendra M

2014-01-01

59

Mandibular first molar with a radix entomolaris: an endodontic dilemma.  

PubMed

It is known that the mandibular first molar can display significant anatomical variations namely the number of root canals, the number of roots and morphology. Mandibular molars may sometimes have an additional root located lingually (the radix entomolaris) or buccally (the radix paramolaris). If encountered, an awareness and understanding of this unusual root and its canal morphology can contribute to the successful outcome of root canal treatment. This case report discusses endodontic treatment of a mandibular first molar with a radix entomolaris, which is a rare entity and poses as an endodontic dilemma for the clinician with respect to diagnosis and subsequent treatment. Clinicians should be aware of these unusual root morphologies in the mandibular first molar which needs strategic treatment as unfilled canals remain a nidus for infection and can compromise treatment outcome. PMID:24910685

Sarangi, Priyanka; Uppin, Veerendra M

2014-01-01

60

Influence of molar ratios on properties of magnesium oxychloride cement  

SciTech Connect

A parametric study has been conducted to investigate the influences of the molar ratios of MgO/MgCl{sub 2} and H{sub 2}O/MgCl{sub 2} on the properties of magnesium oxychloride (MOC) cement. By an integrated assessment of the experimental studies of strength development and X-ray diffractograms, together with application of the relevant phase diagram, it is recognized that the molar ratios of MgO/MgCl{sub 2} and H{sub 2}O/MgCl{sub 2} can significantly affect the properties of MOC cement. For a MOC cement paste possessing a dominance of 5MgO.MgCl{sub 2}.8H{sub 2}O (phase 5) crystals, the molar ratios of MgO/MgCl{sub 2} of 11-17 and H{sub 2}O/MgCl{sub 2} of 12-18 are found to be the most favorite ranges for design purpose. The choose of the molar ratio of H{sub 2}O/MgCl{sub 2} is, however, largely depends on the molar ratio of MgO/MgCl{sub 2} mainly for controlling workability of paste. Therefore, the most critical parameter to be selected in the design process is the molar ratio of MgO/MgCl{sub 2}, although the reactivity of the MgO powder is also important. Besides, the molar ratio can also be affected by the reactivity of the MgO powder to be employed. It is believed that a molar ratio of MgO/MgCl{sub 2} of 13, the most suitable one shown in this study, can be used as a starting point in the normal practice.

Li Zongjin [Department of Civil Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong (China)]. E-mail: zongjin@ust.hk; Chau, C.K. [Department of Civil Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong (China)

2007-06-15

61

Finite Element Reconstruction of a Mandibular First Molar  

PubMed Central

Introduction Mandibular first molar is the most important tooth with complicated morphology. In finite element (FE) studies, investigators usually prefer to model anterior teeth with a simple and single straight root; it makes the results deviate from the actual case. The most complicated and time-consuming step in FE studies is modeling of the desired tooth, thus this study was performed to establish a finite element method (FEM) of reconstructing a mandibular first molar with the greatest precision. Materials and Methods An extracted mandibular first molar was digitized, and then radiographed from different aspects to achieve its outer and inner morphology. The solid model of tooth and root canals were constructed according to this data as well as the anatomy of mandibular first molar described in the literature. Result A three-dimensional model of mandibular first molar was created, giving special consideration to shape and root canal system dimensions. Conclusion This model may constitute a basis for investigating the effect of different clinical situations on mandibular first molars in vitro, especially on its root canal system. The method described here seems feasible and reasonably precise foundation for investigations.

Ehsani, Sara; Mirhashemi, Fatemeh Sadat; Asgary, Saeed

2013-01-01

62

Genetic integration of molar cusp size variation in baboons  

PubMed Central

Many studies of primate diversity and evolution rely on dental morphology for insight into diet, behavior, and phylogenetic relationships. Consequently, variation in molar cusp size has increasingly become a phenotype of interest. In 2007 we published a quantitative genetic analysis of mandibular molar cusp size variation in baboons. Those results provided more questions than answers, as the pattern of genetic integration did not fit predictions from odontogenesis. To follow up, we expanded our study to include data from the maxillary molar cusps. Here we report on these later analyses, as well as inter-arch comparisons with the mandibular data. We analyzed variation in two-dimensional maxillary molar cusp size using data collected from a captive pedigreed breeding colony of baboons, Papio hamadryas, housed at the Southwest National Primate Research Center. These analyses show that variation in maxillary molar cusp size is heritable and sexually dimorphic. We also estimated additive genetic correlations between cusps on the same crown, homologous cusps along the tooth row, and maxillary and mandibular cusps. The pattern for maxillary molars yields genetic correlations of one between the paracone-metacone and protocone-hypocone. Bivariate analyses of cuspal homologues on adjacent teeth yield correlations that are high or not significantly different from one. Between dental arcades, the non-occluding cusps consistently yield high genetic correlations, especially the metaconid-paracone and metaconid-metacone. This pattern of genetic correlation does not immediately accord with the pattern of development and/or calcification, however these results do follow predictions that can be made from the evolutionary history of the tribosphenic molar.

Koh, Christina; Bates, Elizabeth; Broughton, Elizabeth; Do, Nicholas T.; Fletcher, Zachary; Mahaney, Michael C.; Hlusko, Leslea J.

2010-01-01

63

Thiomers: influence of molar mass on in situ gelling properties.  

PubMed

The aim of this study was to investigate the influence of molar mass of thiolated polymers (thiomers) on their in situ gelling properties. Chitosan-thioglycolic acid (chitosan-TGA) and pectin-cysteine (pectin-Cys) of increasing molar mass were chosen to produce in situ gels in combination with carbamide peroxide. Low molar mass chitosan (~2 kDa) was prepared by oxidative degradation with NaNO(2), whereas pectin was depolymerized by heat treatment. Thiomers, displaying 1271-1616 ?mol (chitosan-TGA) and 305-403 ?mol (pectin-Cys) free thiol groups per gram polymer, were synthesized via amide bond formation mediated by a carbodiimide. The results showed that a reduction of molar mass combined with increased concentrations of both cationic chitosan-TGA and anionic pectin-Cys leads to higher final viscosities and to a higher relative increase in viscosity within 60 min and 180 min, respectively. Using this method, the dynamic viscosity of a very low molar mass chitosan-TGA (~2 kDa) could be increased 100,000-fold within 60 min and 390,000-fold within 180 min. In view of these in situ gelling properties carbohydrate thiomers might be useful for various pharmaceutical applications such as vehicle for drug delivery or as wound dressing material. PMID:22683454

Hintzen, Fabian; Laffleur, Flavia; Sarti, Federica; Shahnaz, Gul; Bernkop-Schnürch, Andreas

2012-10-15

64

Surgical extraction of mandibular third molar in pterygomandibular space: a case report  

PubMed Central

Impacted mandibular third molars are located between the second mandibular molar and mandibular ramus. However, ectopic mandibular third molars with heterotopic positions are reported in the subcondylar or pterygomandibular space. The usual cause of malposition is a cyst or tumor, and malposition without a pathology is rare. This case report described an impacted mandibular third molar in the pterygomandibular space without any associated pathology.

Lee, Young-Kyu; Park, Sung-Soo

2013-01-01

65

Efficacy of Postoperative Prophylactic Antibiotic Therapy in Third Molar Surgery  

PubMed Central

Introduction: Surgical extraction of mandibular third molar is the most frequently performed procedure in oral surgery. This procedure is associated with significant postoperative sequelae such as trismus, swelling, pain and infection. The need of antibiotic therapy during the removal of mandibular third molar has been a contentious issue. Method: This study investigated a regimen by using amoxycillin and metronidazole in one group and without using antibiotics in the other. Both the groups were assessed postoperatively on the 1st, 2nd, 5th, 7th and 10th days by the same observer for post operative mouth opening (interincisal distance), presence of a purulent discharge at the site of surgery, pain and swelling. Result: Overall, no statistically significant difference was seen between both the treatment groups when interincisal distance, pain, swelling and purulent discharge were considered. Conclusion: The results of this study failed to show any advantage which was associated with the routine postoperative use of antibiotics in asymptomatic third molar surgeries.

Reddy B, Praveen

2014-01-01

66

[Hypodontia with anlage of all four third molars].  

PubMed

Orthopantomographic films and anamnestic data of 1553 orthodontic patients presenting four third molars were evaluated for tooth agenesis. Agenesis was found in 94 patients (6.1%). There were no significant differences between male and female patients. The most commonly missing teeth were the lower second premolars followed by the upper lateral incisors and the upper second premolars in decreasing order of frequency. Compared with the data in the literature, these results suggest that agenesis occurs less frequently in patients with anlage of all four third molars. PMID:2269104

Roth, P; Hirschfelder, U

1990-05-01

67

Treatment of Ectopic Mandibular Second Permanent Molar with Elastic Separators  

PubMed Central

Ectopic eruption is a developmental disturbance in which the tooth fails to follow its normal eruption pathway. Ectopic eruption of the second molar is relatively rare. This paper presents the case of thirteen-year-old male with an ectopic mandibular second permanent molar. The condition was corrected with surgical exposure and placement of elastic separators. This case report lays emphasis on the practice of basic methods to obtain acceptable results rather than extensive surgical or orthodontic corrections. It is advised that ectopic teeth should not be neglected especially when it concerns developing caries and malocclusion.

Rajesh, R.; Naveen, V.; Amit, S.; Baroudi, Kusai; Sampath Reddy, C.; Namineni, Srinivas

2014-01-01

68

On the Molar Extinction Coefficient and Integrated Molar Absorptivity of the Infrared Absorption Spectra of C60 and C70 Fullerenes  

Microsoft Academic Search

The molar extinction coefficients, known also as molar absorptivity ?, of C60 and C70 fullerenes infrared absorption spectra were determined at room temperature on samples embedded in KBr pellets. Furthermore, the integrated molar absorptivity ? of each absorption infrared band either of C60 and of C70 was measured and reported together with the relative intensity of the infrared absorption bands.

Franco Cataldo; Susana Iglesias-Groth; Arturo Manchado

2012-01-01

69

Forces produced by lip bumpers on mandibular molars  

Microsoft Academic Search

The purpose of this study was to measure the forces produced by a lip bumper on the mandibular permanent first molars. The forces in a simple of 38 patients were measured bilaterally with specially designed gauges at rest but with their lips lightly touching, speaking the words church, phone, and pop, and swallowing water. Forces were compared between two types

John J. Hodge; Ram S. Nanda; Joydeep Ghosh; David Smith

1997-01-01

70

[Unusual complication of extraction of a third molar].  

PubMed

The authors summarized the technical problems of the Wisdom teeth extraction. They advised to send the patients from the basic dental service to the aMaxillofacial Surgery Departments if the position of tooth is unfavourable. They reported a complicated case of the third molar extraction. PMID:10423921

Szabó, C; Csáki, G; Bögi, I

1999-06-01

71

Mathematical analysis of furcation angle in extracted mandibular molars  

PubMed Central

Background: Multi-rooted teeth with furcation involvement exhibit a poorer prognosis when compared to single rooted teeth. The furcation angle (formed by the divergent roots and the roof) may exert a considerable influence on the accessibility for both home care maintenance and instrumentation during periodontal therapy. As there are few anatomy based reports, the furcation angle has not yet been delineated. Materials and Methods: Furcation angle (FA) was mathematically evaluated in extracted mandibular first and second molar teeth, using the Computer-aided design - computer-aided manufacturing technology. Results: The furcations were divided into three groups (Group I: <30°, Group II: 30°-60°, Group III: >60°) based on the furcation angle and their prevalence. The first molar showed greater prevalence of group II FA, while second molar showed a greater prevalence of group III FA. Conclusion: Linear, two dimensional measurements may not accurately reflect the complexities of the furcation area which exhibits considerable intermolar and intramolar (buccal and lingual furcations of second molar) variation.

James, Johnson R.; Arun, K. V.; Talwar, Avaneendra; Kumar, T. S. S.

2013-01-01

72

The Partly Molar Pregnancy That Is Not a Partial Mole  

Microsoft Academic Search

The presence of a fetus in a molar pregnancy is usually an indication that it is a partial, rather than a complete, hydatidiform mole. The underlying reason for this is a basic difference in the genetic composition of the 2 types of mole. Complete moles are ‘‘androgenetic’’ conceptions, i.e., their genome is entirely paternal in origin [1]. The total absence

Harshwardhan M. Thaker

2005-01-01

73

The current clinical presentation of complete molar pregnancy  

Microsoft Academic Search

Objective: To study the current clinical presentation of complete molar pregnancy. Method: Retrospective study of the clinical and ultrasonographic records of 41 patients with complete hydatidiform mole. Results: 17 (41%) patients were asymptomatic. 24 patients (58%) presented with vaginal bleeding, 6 (15%) had excessive uterine size,\\u000a 1 (2%) had anemia and 1 (2%) had hyperemesis. Non of the patients had

Ofer Gemer; Shmuel Segal; Alexander Kopmar; Essi Sassoon

2000-01-01

74

A geometric morphometric analysis of hominin upper first molar shape  

Microsoft Academic Search

Recent studies have revealed interesting differences in upper first molar morphology across the hominin fossil record, particularly significant between H. sapiens and H. neanderthalensis. Usually these analyses have been performed by means of classic morphometric methods, including the measurement of relative cusp areas or the angles defined between cusps. Although these studies have provided valuable information for the morphological characterization

A. Gómez-Robles; M. Martinón-Torres; J. M. Bermúdez de Castro; A. Margvelashvili; M. Bastir; J. L. Arsuaga; A. Pérez-Pérez; F. Estebaranz; L. M. Martínez

2007-01-01

75

Survival rates of porcelain molar crowns-an update.  

PubMed

The aim of this study was to identify recent studies that dealt with the clinical performance of porcelain molar crowns and to explore the possibility of grouping the findings from similar studies together to draw overall conclusions. A MEDLINE literature search was conducted in early 2009 covering the preceding 12 years. Seventeen studies were indentified. However, only seven met the specific inclusion criteria and were analyzed. Among seven studies, five European countries were covered. Five studies reported on Procera AllCeram molar crowns while one reported on In-Ceram Alumina and Spinell crowns and another on CEREC crowns. For comparison, one additional study that reported on premolar crowns was included. In the five Procera AllCeram studies, 235 molar crowns were evaluated for 5 or more years, of which 24 failed. When the results of the five studies on the performance of Procera AllCeram molar crowns were considered collectively, an overall failure rate of 10.2% was found at 5 or more years. Int J Prosthodont 2010;23:60-62. PMID:20234895

Kassem, Amr Shebl; Atta, Osama; El-Mowafy, Omar

2010-01-01

76

Studies of viscosity and excess molar volume of binary mixtures  

Microsoft Academic Search

The excess molar volume VE viscosity deviation ??, excess viscosity ?ln ? and excess Gibbs energy of activation ?G*E of viscous flow have been investigated from the density ? and viscosity ? measurements of seven binary mixtures of propylamine with ethanol, propanol, butanol, pentanol, heptanol, octanol and decanol over the entire range of mole fractions at 303.15 and 313.15 K.

S. L Oswal; H. S Desai

1998-01-01

77

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

78

Third Molar Polymorphism and the Timing of Tooth Formation  

Microsoft Academic Search

AGENESIS (congenital absence) of the third molar tooth is a familiar polymorphism in man, with a population frequency of at least 9 per cent in Europeans1. Hitherto, congenital absence of this tooth has been considered as an independent trait, or at most associated with reduction in size when agenesis is incomplete. However, there is evidence connecting the presence or absence

Stanley M. Garn; Arthur B. Lewis; Batsheva Bonné

1961-01-01

79

A permanent mandibular second molar with seven root canal systems.  

PubMed

This case report illustrates the nonsurgical endodontic management of a seven-canaled mandibular second molar. The root canal configuration presented as four mesial and three distal canals. Identification of the canal system was made with the aid of magnification, ultrasonics, and multiple angulated radiographs. Postoperative examination at 18 months showed a clinically asymptomatic tooth with resolution of the periapical pathology. PMID:24634902

Kottoor, Jojo; Paul, Kuriachan Kottanathu; Mathew, Joy; George, Saira; Mathew, Jain; Roy, Arun

2014-05-01

80

Genotype, phenotype, and developmental biology of molar tooth characters  

Microsoft Academic Search

Primate molar shapes reflect developmental and ecological processes. Development may constrain as well as facilitate evolution of new tooth shapes, affecting how reliable dental characters are in phylogenetic studies. Much of the genetic machinery of development uses the same genes among different organs, including teeth, limbs, and feathers. Furthermore, within a tooth, the development of individual cusps repeatedly uses the

Jukka Jernvall

2000-01-01

81

Solutions : WtPercentToMolarity (4 Variations)  

NSDL National Science Digital Library

A common concentration unit used commercially is percent weight per volume (%W/V) which is the number of grams of solute in 100 mL of solution. A bottle of vinegar contains 5 %W/V acetic acid (CH 3 COOH). What is the molar concentration of acetic acid in the vinegar?

82

Influence of third molar space on angulation and dental arch crowding.  

PubMed

The influence of the third molars on mandibular incisor crowding has been extensively studied but remains controversial. The purpose of this study was to ascertain whether, in Mongolian subjects, the lower third molar can affect anterior crowding and/or the inclination of teeth in the lower lateral segments. Panoramic radiographs, 45° oblique cephalograms, and dental casts were taken from Mongolian subjects (age range 18.3-24.1 years, mean 21.0 years) exhibiting impaction of all four third molars and an Angle Class I molar relationship. The Ganss ratio was calculated using panoramic radiographs, whereas the gonial angle and angulation of lower canines, premolars and molars were measured using 45° oblique cephalograms. Little's index of irregularity was calculated using dental casts. Significant relationships between the angulation of the third and second molars and between the first molars and second premolars were found. Conversely, there was no significant correlation between the angulation of third molars, first premolars and canines. The Ganss ratio calculations showed that the lower first and second molars and the second premolars inclined mesially if there was insufficient space for the lower third molars. However, there was no significant correlation between Little's index of irregularity and third molar angulation. Furthermore, although the third molar influences the lateral segments, no obvious relationship between the third molar and anterior crowding was observed. Therefore, the angulation of the third molar appears not to cause anterior crowding. PMID:22527908

Hasegawa, Yuh; Terada, Kazuto; Kageyama, Ikuo; Tsuchimochi, Takashi; Ishikawa, Fujiro; Nakahara, Sen

2013-01-01

83

Molar luxations caused by holding water taps. Report of five cases.  

PubMed

Luxation of a primary molar occurs rarely. Here, we describe five cases of primary molar luxation caused by holding a water tap pipe in the mouth during bathing. The patients were aged 16 to 19 months and the mandibular first primary molar was affected in all five cases. The second primary molar had not erupted. It is assumed that the flange of the pipe got stuck in the interdental space between the mandibular primary canine and first primary molar and the affected first molar was pushed out by force with the flange acting as a lever. PMID:24579277

Horie, Norio; Hino, Shunsuke; Fukai, Shunichi; Kaneko, Takahiro; Shimoyama, Tetsuo

2013-01-01

84

Partial Molar Volumes for Lanthanide Sesquioxides in Sodium Silicate Melts  

NASA Astrophysics Data System (ADS)

Lanthanides are of great interest in igneous petrology as trace indicators of magmatic processes that control the origin and evolution of igneous rocks. A key to the petrogenetic modelling of magmatic processes and to determine the phase diagrams of lanthanide host phases is the accurate determination of the physico-chemical and thermodynamic properties of lanthanide-containing materials, such as the volumetric properties of lanthanide-bearing silicate melts. Therefore, we have undertaken to provide a new reliable volumetric data set for lanthanide-bearing silicate melts which allows the available models in the literature to be extended to lanthanide-bearing melts. For this purpose, the densities of various lanthanide-bearing silicate melts distributed along various pseudo-binary joins, where the end-members are Na-disilicate and one of the lanthanide sesquioxides (i.e., Ce2O3, Pr2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3 and Yb2O3), have been measured using the double-bob Archimedean method. The present results show that the addition of any lanthanide to Na-disilicate leads to an increase in the melt density and that the melt density increases with increasing atomic number of the lanthanide. From the present density data set, the molar volumes of these melts have been calculated and the partial molar volumes of each lanthanide sesquioxide in these melts have been determined using a linear regression through each pseudo-binary join (i.e., Na-disilicate - lanthanide sesquioxide). This study indicates ideal behaviour with respect to the molar volume (i.e., a linear variation of the molar volume along each pseudo-binary join) for Na-silicate melts containing up to 10 mol% of lanthanide oxide. Comparison between the partial molar volumes of lanthanide sesquioxides obtained in this study and the molar volumes of molten lanthanide sesquioxides given in the literature raise the possibility however that this ideality is not maintained along the entire Na-disilicate - lanthanide sesquioxide pseudo-binary joins. Excess volumes of mixing appear to be required to describe the combined volumetric data set.

Courtial, P.; Dingwell, D. B.

2004-12-01

85

Molar extinction coefficients of the cupric ion in silicate glasses  

Microsoft Academic Search

The absorption characteristics of Cu2+ ions in binary alkali silicate and ternary silicate glasses were investigated. The molar extinction coefficients of the Cu2+ ion were determined in a series of binary alkali silicate and a ternary soda-lime-silica glasses for the actual intensities of the observed bands at their wavelength maxima. The absorption maxima due to Cu2+ ions were found to

S. P. Singh; A. Kumar

1995-01-01

86

Temporal abscess after third molar extraction in the mandible  

Microsoft Academic Search

Background  Dental infections resulting before or after third molar removal are complications in which the maxillofacial surgeon may have\\u000a to initiate an earlier management. The severe dental infections resulting before or after this procedure is one of the few\\u000a life-threatening complications in which the maxillofacial surgeon may have to initiate an earlier management. Infections involving\\u000a the temporal space are rare and

Patrício José de Oliveira Neto; Maximiana Cristina de Souza Maliska; Renato Sawazaki; Luciana Asprino; Márcio de Moraes; Roger William Fernandes Moreira

87

Better outcomes in pulpotomies on primary molars with MTA  

Microsoft Academic Search

Data sourcesMedline, Cochrane Library, Embase, Science Citation Index and the China National Knowledge Infrastructure were used to source articles. In addition, identified papers' reference lists and their authors' other published literature were also scanned.Study selectionStudies of interest were randomised controlled trials of primary molar teeth where there was exposure of vital pulp caused by caries or trauma, with at least

Nicola Innes

2007-01-01

88

Molar concentration effect on MgO thin films properties  

Microsoft Academic Search

Magnesium Oxide, MgO is inorganic material with wide band gap (7.8eV) and suitable to be used as dielectric layer. Due to its chemical and structural properties, MgO also can be used as template to prepare ferroelectric thin film [1–3]. In this work, MgO thin films with different molar concentration from 0.1M to 1M were prepared using sol-gel spin coating technique.

Habibah Zulkefle; Lyly Nyl Ismail; Raudah Abu Bakar; Mohamad Rusop Mahmood

2011-01-01

89

Evaluation of Impacted Mandibular Third Molars by Panoramic Radiography  

PubMed Central

Objective. The study was to evaluate impacted mandibular third molars (IM3M) for their angulation, level of eruption, third molar space and relation of inferior alveolar canal with their roots. Methods. Total 988 IM3M were studied in 578 individuals of age 18?years and above, dividing them into three groups i.e. symptomatic, asymptomatic and radiographic only. Individuals were also divided according to age, sex and side of IM3M (right or left). Panoramic radiographs were obtained after written consent and traced. ?2-test was applied to check inter-group and intra-group significance. Result. Out of 578 individuals 307 (53.11%) were males and 271 (46.89%) females. Maximum number of IM3M were in 18-27?years age group (398 i.e. 68.89%). Out of 988 IM3M, 39.93% were vertically placed. 61.84% IM3M were found at level A. Class II (79.65%) was the most common relation for third molar space. Notching (12.55%) was most common true inferior alveolar canal and IM3M root relation whereas superimposed (41.80%) was most common false inferior alveolar canal and IM3M root relation. For all the criteria significant inter-group difference was found (considering P < .05) and intra-group difference was non significant. Conclusion and significance. Panoramic radiographs can be used as reliable investigation for evaluation of IM3M.

Gupta, Siddharth; Bhowate, Rahul R.; Nigam, Nitin; Saxena, Sonal

2011-01-01

90

Quality of life following third molar removal under conscious sedation  

PubMed Central

Aim: The aim of this study was to assess quality of life (QoL) and degree of satisfaction among outpatients subjected to surgical extraction of all four third molars under conscious sedation. A second objective was to describe the evolution of self-reported pain measured in a visual analogue scale (VAS) in the 7 days after extraction. Study design: Fifty patients received a questionnaire assessing social isolation, working isolation, eating and speaking ability, diet modifications, sleep impairment, changes in physical appearance, discomfort at suture removal and overall satisfaction at days 4 and 7 after surgery. Pain was recorded by patients on a 100-mm pain visual analogue scale (VAS) every day after extraction until day 7. Results: Thirty-nine patients fulfilled correctly the questionnaire. Postoperative pain values suffered small fluctuations until day 5 (range: 23 to 33 mm in a 100-mm VAS), when dicreased significantly. A positive association was observed between difficult ranked surgeries and higher postoperative pain levels. The average number of days for which the patient stopped working was 4.9. Conclusion: The removal of all third molars in a single appointment causes an important deterioration of the patient’s QoL during the first postoperative week, especially due to local pain and eating discomfort. Key words:Third molar removal, quality of life, sedation.

Sancho-Puchades, Manuel; Berini-Aytes, Leonardo; Gay-Escoda, Cosme

2012-01-01

91

Group Contribution to Molar Refraction and Refractive Index of Conjugated Polymers.  

National Technical Information Service (NTIS)

The functional group contribution to molar refraction and refractive index of pi-conjugated polymers has been evaluated from the available refractive index dispersion data for 33 conjugated polymers. The Lorentz-Lorenz molar refraction (Ru) of 24 function...

C. J. Yang S. A. Jenekhe

1996-01-01

92

Correlation of Acute Pericoronitis and the Positon of the Mandibular Third Molar.  

National Technical Information Service (NTIS)

Acute pericoronitis is a painful, debilitating infection that is most commonly found among young adults with erupting mandibular third molars. Prophylactic removal of third molars to prevent this disease has been advocated, but this procedure requires an ...

S. A. Leone M. J. Edenfield M. E. Cohen

1987-01-01

93

Hypercementosis and concrescence of maxillary second molar with third molar: a case report and review of literature.  

PubMed

Concrescence signifies a rare developmental alteration, most commonly in maxillary molars,where two fully formed teeth with separate root canal structures are fused with cementum. Clinical detection is difficult due to lack of enamel involvement and radiographic detection may be challenging, as two dimensional images may be misdiagnosed as overlap, superimposition or close proximity of roots. Such a developmental anomaly can influence treatment outcomes for extraction, endodontic, periodontic, prosthodontic and orthodontic treatment. Legal complications could arise due to unexpected difficulties following treatment. Awareness of occurrence, incidence and post treatment implications of such anomalies is paramount for both the patient and clinician's benefit. This article discusses a case report of concrescence between two maxillary molar teeth and its management. PMID:24984682

Mohan, Bhavya

2014-06-01

94

A comparative study between lip bumper and headgear as maxillary molar retainers following distalization.  

PubMed

Abstract: There are many appliances that can be used to correct molar relationship, achieving upper molar distalization, in Class II malocclusion. This research aimed to study the dental effects promoted by lip bumper to retain maxillary molars that had previously been distalized using a Cetlin appliance in conjunction with headgear. PMID:23094556

Silva, Rafael Games Corrêa; Kaieda, Armando Koichiro; Paranhos, Luiz Renato; Angelieri, Fernanda; Torres, Fernando César; Scanavini, Marco Antônio

2012-01-01

95

Influence of Alkoxide Molar Ratio on Rheological Study of Alumina Sol for Fiber Preparation  

Microsoft Academic Search

Various molar ratio of aluminium isopropoxide (ALP) to aluminium nitrate nonahydrate (ALN) ranging from 1 to 5 were studied to determine suitable molar ratio in producing alumina fiber. Spinnability characteristics obtained only from intermediate molar ratio, 3, where the rheological shows Newtonian behavior. The spinned gel fiber were calcined at different temperatures ranging from 500°C to 1200°C. The rheological studies

M. Hasmaliza; M. N. Ahmad Fauzi; A. Zainal Arifin

2008-01-01

96

Mandibular third molar development after mantle radiation in long-term survivors of childhood Hodgkin's disease  

SciTech Connect

Sequential panoramic radiographs were assessed for mandibular third molar development in 47 long-term survivors of childhood Hodgkin's disease after treatment with 37 Gy mantle field radiation. To make a comparison, panoramic radiographs of 149 healthy, nonirradiated children were reviewed for the presence of mandibular third molars. In children between the ages of 7 and 12 years, bilateral agenesis of mandibular third molars was more frequent in patients who had been treated with mantle radiation than in nonirradiated patients. Unilateral agenesis, crown hypoplasia, and root growth impairment of mandibular third molars were also found. Similar, apparent, radiation-induced developmental anomalies were noted in maxillary third molars of the irradiated patients.

McGinnis, J.P. Jr.; Hopkins, K.P.; Thompson, E.I.; Hustu, H.O.

1987-05-01

97

Effect of bite force on orthodontic mini-implants in the molar region: Finite element analysis  

PubMed Central

Objective To examine the effect of bite force on the displacement and stress distribution of orthodontic mini-implants (OMIs) in the molar region according to placement site, insertion angle, and loading direction. Methods Five finite element models were created using micro-computed tomography (microCT) images of the maxilla and mandible. OMIs were placed at one maxillary and two mandibular positions: between the maxillary second premolar and first molar, between the mandibular second premolar and first molar, and between the mandibular first and second molars. The OMIs were inserted at angles of 45° and 90° to the buccal surface of the cortical bone. A bite force of 25 kg was applied to the 10 occlusal contact points of the second premolar, first molar, and second molar. The loading directions were 0°, 5°, and 10° to the long axis of the tooth. Results With regard to placement site, the displacement and stress were greatest for the OMI placed between the mandibular first molar and second molar, and smallest for the OMI placed between the maxillary second premolar and first molar. In the mandibular molar region, the angled OMI showed slightly less displacement than the OMI placed at 90°. The maximum Von Mises stress increased with the inclination of the loading direction. Conclusions These results suggest that placement of OMIs between the second premolar and first molar at 45° to the cortical bone reduces the effect of bite force on OMIs.

Lee, Hyeon-Jung; Lee, Kyung-Sook; Kim, Min-Ji

2013-01-01

98

Assessment of the relationship between the maxillary molars and adjacent structures using cone beam computed tomography  

PubMed Central

Purpose This study investigated the relationship between the roots of the maxillary molars and the maxillary sinus using cone beam computed tomography (CBCT), and measured the distances between the roots of the maxillary molars and the sinus floor as well as the thickness of the bone between the root and the alveolar cortical plate. Materials and Methods The study sample consisted of 83 patients with normally erupted bilateral maxillary first and second molars. A total of 332 maxillary molars were examined using CBCT images. The vertical relationship of each root with the maxillary sinus was classified into four types on CBCT cross-sectional images. The distance between the sinus floor and root and the bone thickness between the root and alveolar cortical plate were measured. Results In the buccal roots of the maxillary molars, a root protruding into the sinus occurred most frequently. A root projecting laterally along the sinus cavity was most common in the palatal roots of the maxillary first molars. The mesiobuccal roots of the maxillary second molar were closest to the sinus. The mesiobuccal roots of the first molars were closest to the cortical plate. Conclusion The relationship between the roots of the maxillary molars and the sinus differed between the buccal and palatal roots. A root protruding into the sinus occurred more frequent in the buccal roots of the maxillary molars. The mesiobuccal root of the maxillary second molar was closest to the maxillary sinus floor and farthest from the alveolar cortical plate.

Jung, Yun-Hoa

2012-01-01

99

Histological evaluation of mandibular third molar roots retrieved after coronectomy.  

PubMed

There is a resurgence of interest in coronectomy for the management of mandibular third molars because it has a low risk of injury to the inferior dental nerve. However, there is concern that the root that is left in place will eventually become a source of infection. We describe the histological evaluation of 26 consecutive symptomatic coronectomy roots in 21 patients. All roots had vital tissue in the pulp chamber and there was no evidence of periradicular inflammation. Persistent postoperative symptoms related predominantly to inflammation of the soft tissue, which was caused by partially erupted roots or failure of the socket to heal. PMID:24684971

Patel, Vinod; Sproat, Chris; Kwok, Jerry; Beneng, Kiran; Thavaraj, Selvam; McGurk, Mark

2014-05-01

100

Molar extinction coefficients of some carbohydrates in aqueous solutions  

Microsoft Academic Search

Molar extinction coefficients of some carbohydrates viz. L-arabinose (C5H10O5), D-glucose (C6H12O6), D-mannose (C6H12O6), D-galactose (C6H12O6), D(-) fructose (C6H12O6) and maltose (C12H24O12) in aqueous solutions have been determined at 81, 356, 511, 662, 1173 and 1332 keV by gamma ray transmission method in a narrow beam good geometry set-up. These coefficients have been found to depend upon the photon energy following

K. Singh; G. K. Sandhu; B. S. Lark; S. P. Sud

2002-01-01

101

Molar extinction coefficients of some carbohydrates in aqueous solutions  

Microsoft Academic Search

Molar extinction coefficients of some carbohydrates viz. l-arabinose (C5H10O5), d-glucose (C6H12O6), d-mannose (C6H12O6), d-galactose (C6H12O6), d(-) fructose (C6H12O6) and maltose (C12H24O12) in aqueous solutions have been determined at 81, 356, 511, 662, 1173 and 1332 keV by gamma ray transmission method in a\\u000a narrow beam good geometry set-up. These coefficients have been found to depend upon the photon energy following

K Singh; GK Sandhu; BS Lark; SP Sud

2002-01-01

102

Molar extinction coefficients of some commonly used solvents  

Microsoft Academic Search

Molar extinction coefficients of some commonly used solvents (ethanol (C2H5OH), methanol (CH3OH), propanol (C3H7OH), butanol (C4H9OH), water (H2O), toluene (C7H8), benzene (C6H6), carbontetrachloride (CCl4), acetonitrile (C4H3N), chlorobenzene (C6H5Cl), diethylether (C4H10O) and dioxane (C4H8O2)) have been determined by a well-collimated narrow beam transmission geometry at 279, 356, 662, 1173, 1252 and 1332keV ? rays. The total ? ray interaction cross sections

Ashok Kumar; Sukhpal Singh; Gurmel Singh Mudahar; Kulwant Singh Thind

2006-01-01

103

Molar extinction coefficients of some commonly used solvents  

Microsoft Academic Search

Molar extinction coefficients of some commonly used solvents (ethanol (C2H5OH), methanol (CH3OH), propanol (C3H7OH), butanol (C4H9OH), water (H2O), toluene (C7H8), benzene (C6H6), carbontetrachloride (CCl4), acetonitrile (C4H3N), chlorobenzene (C6H5Cl), diethylether (C4H10O) and dioxane (C4H8O2)) have been determined by a well-collimated narrow beam transmission geometry at 279, 356, 662, 1173, 1252 and 1332 keV gamma rays. The total gamma ray interaction cross

Ashok Kumar; Sukhpal Singh; Gurmel Singh Mudahar; Kulwant Singh Thind

2006-01-01

104

Replantation of a maxillary second molar after removal of a third molar with a dentigerous cyst: Case report and 12-month follow-up  

PubMed Central

The aim of this study was to describe the replantation of a maxillary second right molar, which had been removed for surgical reasons in order to remove a dentigerous cyst associated with the adjacent third molar, and the case’s 12-month follow-up. A 51-year-old man presented swelling in the right maxillary area. Radiographic examination showed a large radiolucency in close proximity to the third molar, suggesting a follicular cyst. The third molar was extracted and the cyst underwent curettage. The second molar had to be extracted to enable complete removal of the cyst and to achieve primary closure of the wound, which would have been impossible without repositioning the molar. With this objective, extraoral endodontic treatment was performed, the root-end was resected and prepared with ultrasonic retrotips, and root-end filling was accomplished with MTA before the molar was replanted. At the 12-month follow-up, the tooth showed no clinical signs or symptoms, probing depth was no greater than 3 mm and radiographic examination showed no evidence of root resorption or periapical lesion. Key words:Replantation, maxillary molar, follicular cyst, dentigerous cyst.

Penarrocha-Diago, Maria A.; Penarrocha-Oltra, David; Penarrocha-Diago, Miguel

2014-01-01

105

Extensive composite molar restorations: 3 years clinical evaluation.  

PubMed

Abstract Objective. To evaluate the clinical performance of extensive direct composite restorations in molars after 1 and 3 years and to find out the importance of extent of the restorations and other factors related to their performance. Materials and methods. Seventy-four patients with a molar tooth in need of a restoration covering at least three surfaces and one cusp were selected. Patient-related factors were registered and the tooth was prepared and restored by using a nano-filled composite. A topographic system for classification of extensive posterior restorations was developed. At baseline, the operator recorded a clinical evaluation, using modified USPHS-criteria. After 1 and 3 years, an independent observer evaluated the restorations. Post-operative problems arising during the observation period were registered. Results. A change in clinical score from baseline to the 1 and 3 year recall was recorded for all clinical criteria. A total of nine restorations were graded as unacceptable after 3 years (3-year survival rate of 87.7% and a mean annual failure rate of 4.2%). Except for gender (p = 0.022), none of the patient-related factors investigated (age, caries risk, extension of the restoration and presence of cervical enamel) had a significant influence on the survival of the restorations. Conclusions. Extensive direct posterior composite restorations showed an acceptable clinical performance after 3 years. Men had a significantly greater restoration failure rate than women. PMID:21780983

Laegreid, Torgils; Gjerdet, Nils Roar; Johansson, Ann-Katrin

2012-07-01

106

Sex determination potential of permanent maxillary molar widths and cusp diameters in a North Indian population  

PubMed Central

Aims: To assess the sex discrimination potential of permanent maxillary molar crown widths and cusp diameters. Materials and Methods: Measurements were made on plaster casts of 200 individuals of known sex (100 males, 100 females, aged 12-21 years). Eight parameters were measured on the first and second maxillary molars with a digital caliper [buccolingual, mesiodistal, mesiobuccal-distolingual and distobuccal-mesiolingual crown widths and cusp diameters (hypocone, protocone, paracone, and metacone)]. The percentage of sexual dimorphism for each parameter was calculated. Discriminant function analysis was used to determine the accuracy of sex determination for each molar separately and both the molars taken together. Results: The highest sexual dimorphism was shown by protocone in the first molar and hypocone in the second molar. Furthermore, the sex determination accuracy was highest when the first molar was taken alone than when the second molar or the first and second molars were taken together. Conclusion: Based on this study, odontometric measurements of maxillary molars provide low to moderate sex determination accuracy.

Sharma, Payal; Singh, Tushita; Kumar, Piush; Chandra, Pavan Kumar; Sharma, Rakesh

2013-01-01

107

An Evidenced Based Scoring System To Determine The Periodontal Prognosis On Molars  

PubMed Central

Background This retrospective study evaluated and assigned scores to six prognostic factors and derived a quantitative scoring system used to determine the periodontal prognosis on molar teeth. Methods Data were gathered on 816 molars in 102 patients with moderate to severe periodontitis. The six factors evaluated, age, probing depth, mobility, furcation involvement, smoking, and molar type, were assigned a numerical score based on statistical analysis. The sum of the scores for all factors was used to determine the prognosis score for each molar. Only patients with all first and second molars at the initial examination qualified for the study. All patients were a minimum of 15 years post treatment. Results The post treatment time ranged from 15 to 40 years and averaged 24 years. When the study was completed, 639 molars survived (78%), and of those surviving molars, 566 survived in health (89%). In molars with lower scores (1,2,and 3) the 15-year survival rates ranged from 99% to 96%. For scores 4, 5, 6 the 15 year survival rates ranged was 95% to 90% and for molars with scores of 7, 8, 9, and 10 the survival rates ranged from 86% to 67%. Conclusions Our results indicate that the periodontal prognosis on molars diagnosed with moderate to severe periodontitis can be calculated using an evidence-based scoring system.

Miller, Preston D.; McEntire, Mark L.; Marlow, Nicole M.; Gellin, Robert G.

2014-01-01

108

Periodontal healing after mandibular third molar surgery—A comparison of distolingual alveolectomy and tooth division techniques  

Microsoft Academic Search

The purpose of this study was to compare the periodontal healing of mandibular second molars after the removal of impacted mandibular third molars using distolingual alveolectomy and tooth division techniques. A total of 120 consecutive healthy patients who presented with bilaterally impacted mandibular third molars were included in this study. The same operator removed the impacted third molars on both

H.-H. Chang; J.-J. Lee; S.-H. Kok; P.-J. Yang

2004-01-01

109

[Molar distalization by using vertically installed mini-screws].  

PubMed

Mini-screws can be used for orthodontic anchorage in distalizing maxillary and mandibular molars. With them, practitioners can avoid the undesirable reciprocal movement that so often occurs when teeth are used as anchorage units. In this article, we propose a method of vertical insertion of mini-screws that places them in positions that will not interfere with movement of tooth roots. This allows orthodontists to use mass movements of groups of teeth or even of entire arches, thus reducing the need for extractions, simplifying treatment procedures, and enlarging the range of therapeutic possibilities. We evaluate the indications for this vertical placement in different anatomic situations. We suggest different sites for mini-screw placement and illustrate them with many clinical cases. PMID:23206370

Lee, Ju-Young

2012-12-01

110

[Maxillary first molar with two palatal canals: a case report].  

PubMed

Maxillary first molar with two palatal canals is rare. Clinicians should be aware of the normal anatomy of root canal system and vigilant about the possible existence of canal variation. A patient with acute episode of chronic pulpitis of 26, as presented by the case report, was examined to have four canals, which were the mesial buccal canal, the distal buccal canal, the mesial palatal canal and the distal palatal canal. When suspecting the existence of canal variation, clinicians should carefully explore the pulpal floor, further by changing the X-ray projection angle to confirm the existence of variation and prevent the missed canals, all of which are necessary for a successful root canal therapy. PMID:23852074

Shi, Jian-jun

2013-06-01

111

Molar extinction coefficients of solutions of some organic compounds  

Microsoft Academic Search

Molar extinction coefficients of aqueous solutions of some organic compounds, viz. formamide (CH3NO),N-methylformamide (C2H5NO),NN-dimethylformamide (C3H7NO),NN-dimethylacetamide (C4H9NO), 1,4-dioxane (C4H8O24), succinimide (C4H5NO2) and solutions of acetamide (C2H5NO) and benzoic acid (C7H6O2) in 1,4-dioxane (C4H8O2) have been determined by narrow beam ?-ray transmission method at 81, 356, 511, 662, 1173 and 1332 keV. The experimental\\u000a values of mass attenuation coefficients of these compounds

Kulwant Singh; G. K. Sandhu; B. S. Lark

2004-01-01

112

Molar extinction coefficients of solutions of some organic compounds  

Microsoft Academic Search

Molar extinction coefficients of aqueous solutions of some organic compounds, viz. formamide (CH_{3}NO), N-methylformamide (C_{2}H_{5}NO), NN-dimethylformamide (C_{3}H_{7}NO), NN-dimethylacetamide (C_{4}H_{9}NO), 1,4-dioxane (C_{4}H_{8}O_{2}), succinimide (C_{4}H_{5}NO_{2}) and solutions of acetamide (C_{2}H_{5}NO) and benzoic acid (C_{7}H_{6}O_{2}) in 1,4-dioxane (C_{4}H_{8}O_{2}) have been determined by narrow beam gamma-ray transmission method at 81, 356, 511, 662, 1173 and 1332 keV. The experimental values of mass attenuation coefficients

Kulwant Singh; G. K. Sandhu; B. S. Lark

2004-01-01

113

Molar extinction coefficients of some carbohydrates in aqueous solutions  

NASA Astrophysics Data System (ADS)

Molar extinction coefficients of some carbohydrates viz. L-arabinose (C5H10O5), D-glucose (C6H12O6), D-mannose (C6H12O6), D-galactose (C6H12O6), D(-) fructose (C6H12O6) and maltose (C12H24O12) in aqueous solutions have been determined at 81, 356, 511, 662, 1173 and 1332 keV by gamma ray transmission method in a narrow beam good geometry set-up. These coefficients have been found to depend upon the photon energy following a 4-parameter polynomial. These extinction coefficients for different sugars having the same molecular formula have same values varying within experimental uncertainty. Within concentration ranges studied, Beer--Lambert law is obeyed very well.

Singh, K.; Sandhu, G. K.; Lark, B. S.; Sud, S. P.

2002-03-01

114

Molar extinction coefficients of some commonly used solvents  

NASA Astrophysics Data System (ADS)

Molar extinction coefficients of some commonly used solvents (ethanol (C 2H 5OH), methanol (CH 3OH), propanol (C 3H 7OH), butanol (C 4H 9OH), water (H 2O), toluene (C 7H 8), benzene (C 6H 6), carbontetrachloride (CCl 4), acetonitrile (C 4H 3N), chlorobenzene (C 6H 5Cl), diethylether (C 4H 10O) and dioxane (C 4H 8O 2)) have been determined by a well-collimated narrow beam transmission geometry at 279, 356, 662, 1173, 1252 and 1332 keV ? rays. The total ? ray interaction cross sections of these solvents have also been determined. A good agreement has been obtained between the experimental results with the theoretical values evaluated through XCOM calculations.

Kumar, Ashok; Singh, Sukhpal; Singh Mudahar, Gurmel; Singh Thind, Kulwant

2006-07-01

115

Quantification of chlorinated naphthalenes with GC-MS using the molar response of electron impact ionization  

Microsoft Academic Search

The concept of the molar response (MR) in HRGC\\/EI-MS has been checked for naphthalene and three chlorinated naphthalenes: 1-chloronaphthalene, 1,2,3,4-tetrachloronaphthalene and octachloronaphthalene. The molar response factors increase with increasing degree of chlorination. When the ion yield is normalized for the ionization cross section Q of the molecule, a constant value of injected molar mass to signal intensity is obtained for

Thomas Wiedmann; Karlheinz Ballschmiter

1993-01-01

116

Application of size-exclusion chromatography to polymers of ultra-high molar mass  

Microsoft Academic Search

This article describes the experimental conditions that should be applied to avoid molecular degradation in size-exclusion chromatography of polymers of ultra-high molar mass (weight-average molar mass Mw>5000 kg\\/mol). The applicability of the optimized experimental conditions is demonstrated using polystyrene as a model substance, but also by using polymers of biochemical and biophysical interest, such as polyethylene of ultra-high molar mass,

Nicolai Aust

2003-01-01

117

Submandibular-space abscess from loss of a bonded molar tube during orthognathic surgery.  

PubMed

The use of bonded orthodontic molar tubes is becoming more prevalent in orthodontics because they have some advantages over conventional bonding. However, a bonded apparatus can become detached, leading to complications. This article presents the case of a submandibular-space abscess associated with a molar tube that detached during orthognathic surgery and became embedded in the soft tissues. The site became infected, and antibiotics were prescribed. Eventually, the molar tube migrated and could be removed under local anesthesia. PMID:23631975

de Queiroz, Sormani Bento Fernandes; Curioso, Pedro Augusto Bulhões; Carvalho, Francisco Samuel Rodrigues; de Lima, Valthierre Nunes

2013-05-01

118

Geometric morphometric 3D shape analysis and covariation of human mandibular and maxillary first molars.  

PubMed

Dental casts of 160 Greek subjects (80 males, 80 females) were scanned by a structured-light scanner. The upper and lower right first molar occlusal surface 3D meshes were processed using geometric morphometric methods. A total of 265 and 274 curve and surface sliding semilandmarks were placed on the upper and lower molar surfaces, respectively. Principal component analysis and partial least square analysis were performed to assess shape parameters. Molars tended to vary between an elongated and a more square form. The first two principal components (PCs), comprising almost 1/3 of molar shape variation, were related to mesiodistal-buccolingual ratios and relative cusp position. Distal cusps displayed the greatest shape variability. Molars of males were larger than those of females (2.8 and 3.2% for upper and lower molars respectively), but no shape dimorphism was observed. Upper and lower molar sizes were significantly correlated (r(2) = 0.689). Allometry was observed for both teeth. Larger lower molars were associated with shorter cusps, expansion of the distal cusp, and constriction of the mesial cusps (predicted variance 3.25%). Upper molars displayed weaker allometry (predicted variance 1.59%). Upper and lower molar shape covariation proved significant (RV = 17.26%, P < 0.0001). The main parameter of molar covariation in partial least square axis 1, contributing to 30% of total covariation, was cusp height, in contrast to the primary variability traits exhibited by PC1 and PC2. The aim of this study was to evaluate shape variation and covariation, including allometry and sexual dimorphism, of maxillary and mandibular first permanent molar occlusal surfaces. PMID:24009105

Polychronis, Georgios; Christou, Panagiotis; Mavragani, Maria; Halazonetis, Demetrios J

2013-10-01

119

[Role of lower third molars in the development of dental malocclusion: review of the literature].  

PubMed

The Author's aims was to review the role of the lower third molars in delayed crowding of the jaw. A global agreement exists on the fact that lower molars should be considered only one between several factors able to cause malocclusion. Finally, the germectomy of the third molars has to be performed only in carefully selected patients after a comprehensive diagnostic evaluation of the single case. PMID:2205795

Garattini, G; Grecchi, M T; Vogel, G

1990-01-01

120

Automatic Molar Extraction from Dental Panoramic Radiographs for Forensic Personal Identification  

NASA Astrophysics Data System (ADS)

Measurement of an individual molar provides rich information for forensic personal identification. We propose a computer-based system for extracting an individual molar from dental panoramic radiographs. A molar is obtained by extracting the region-of-interest, separating the maxilla and mandible, and extracting the boundaries between teeth. The proposed system is almost fully automatic; all that the user has to do is clicking three points on the boundary between the maxilla and the mandible.

Samopa, Febriliyan; Asano, Akira; Taguchi, Akira

121

An unusual occurrence of bilaterally geminated mandibular second premolars resulting in premolar molarization: A case report.  

PubMed

Gemination refers to an attempt by a single tooth bud to divide, with a resultant formation of either a large tooth with a bifid crown or two completely divided teeth throughout the crown and root. This report describes a rare case of bilateral gemination of permanent mandibular second premolar tooth giving rise to molarization of premolars. The mesiodistal width of these teeth is similar to mandibular molars, but the cervicoocclusal width is lesser than that of the molar tooth. This paper also discusses the potential orthodontic, periodontal, and endodontic complications of premolar molarization. PMID:24347900

Rajesh Ebenezar, Av; Venkatesh, A; Mary, A Vinita; Mohan, Ajit George

2013-11-01

122

An unusual occurrence of bilaterally geminated mandibular second premolars resulting in premolar molarization: A case report  

PubMed Central

Gemination refers to an attempt by a single tooth bud to divide, with a resultant formation of either a large tooth with a bifid crown or two completely divided teeth throughout the crown and root. This report describes a rare case of bilateral gemination of permanent mandibular second premolar tooth giving rise to molarization of premolars. The mesiodistal width of these teeth is similar to mandibular molars, but the cervicoocclusal width is lesser than that of the molar tooth. This paper also discusses the potential orthodontic, periodontal, and endodontic complications of premolar molarization.

Rajesh Ebenezar, AV; Venkatesh, A; Mary, A Vinita; Mohan, Ajit George

2013-01-01

123

Reduced radiation-absorbed dose to tissues with partial panoramic radiography for evaluation of third molars  

SciTech Connect

The radiation-absorbed doses from panoramic radiography, distal molar radiography, and a partial panoramic radiographic technique that exposes only the third molar region to radiation are compared. Doses of radiation to the submandibular salivary gland were comparable by all three techniques, but doses of radiation to the head and neck were reduced greatly by the partial panoramic radiographic technique. Partial panoramic radiography is a diagnostically satisfactory and a radiologically safer technique for evaluation of third molar pathosis than is panoramic or distal molar radiography.

Kircos, L.T.; Eakle, W.S.; Smith, R.A.

1986-05-01

124

Excess molar volumes and excess molar enthalpies of binary mixtures for 1,2-dichloropropane + 2-alkoxyethanol acetates at 298.15 K  

Microsoft Academic Search

The excess molar volumes VmE and excess molar enthalpies HmE over the whole range of composition have been measured for the binary mixtures formed by 1,2-dichloropropane (1,2-DCP) with three 2-alkoxyethanol acetates at 298.15K and atmospheric pressure using a digital vibrating-tube densimeter and an isothermal calorimeter with flow-mixing cell, respectively. The 2-alkoxyethanol acetates are ethylene glycol monomethyl ether acetate (EGMEA), ethylene

D. Sen; M. G. Kim

2008-01-01

125

The influence of impaction to the third molar mineralization in northwestern Chinese population.  

PubMed

Age estimation by third molar mineralization has been developed for a period of time. Recent studies showed that impaction status has an influence on the rate of the third molar mineralization in Europids and male Black African populations. In this regard, the present study was conducted to determine whether the impaction status could delay the chronological process of third molar mineralization in northwestern Chinese population too. A total of 3,512 digital orthopantomograms of 1,255 male and 2,257 female northwestern Chinese subjects aged from 11 to 26 years were assessed based on the formation stages described by Demirjian et al. with two modifications. Mineralization stage and impaction status were determined for all third molars. Statistical measures were calculated at stages C-H in the male and female gender for both impacted and non-impacted third molars. It was ascertained that the mean ages with impacted third molars at stages C-H were 0.02-1.42 years higher in males and 0.04-1.52 years higher in females than those with non-impacted third molars, but statistical differences were only found at stages C, D, and E in males and stages D and E in females. The probabilities of being under 14, 16, or 18 years of age with non-impacted third molars were all higher than those with impacted third molars. The results prove that impacted third molars show significant slower mineralization than non-impacted ones at stages D and E in both males and females of northwestern Chinese population. It is recommended to consider the influence of impaction on the rate of third molar mineralization for dental age estimation. PMID:24532176

Guo, Yu-cheng; Yan, Chun-xia; Lin, Xing-wei; Zhang, Wen-tao; Zhou, Hong; Pan, Feng; Wei, Lai; Tang, Zheng; Liang, Feng; Chen, Teng

2014-07-01

126

Electro-acupuncture efficacy on pain control after mandibular third molar surgery  

Microsoft Academic Search

The aim of this study was to evaluate the efficacy of electro-acupuncture (EAC) on postoperative pain control after mandibular third molar surgery. Twenty four young patients (12 male and 12 female) with symmetrically impacted mandibular third molars were selected. Each patient was submitted to two separate surgical procedures under local anesthesia. At one side, extraction was carried out employing both

Marconi Gonzaga Tavares; Ana Paula Machado; Breno Gutierrez Motta; Maria Cristina Borsatto; Adalberto Luiz Rosa; Samuel Porfírio Xavier

2007-01-01

127

Comparison of mineral trioxide aggregate and formocresol as pulp medicaments for pulpotomies in primary molars  

Microsoft Academic Search

Purpose The aim of this study was to compare the effect of white mineral trioxide aggregate (MTA) to that of formocresol (FC) as pulp dressing agents in pulpotomised primary molars.Methods In this clinical trial study, 60 lower second primary molars of 46 children were treated by a conventional pulpotomy technique. The teeth were randomly assigned to the MTA (experimental) and

H. Noorollahian

2008-01-01

128

Long-term Evaluation of Pulpotomy in Primary Molars Using Mineral Trioxide Aggregate or Formocresol  

Microsoft Academic Search

Purpose. The objective of this study was to assess the effect of mineral trioxide aggre- gate (MTA) as pulp dressing material following pulpotomy in primary molars with carious pulp exposure and compare them to those of formocresol (FC). Methods. Of 33 children, primary molars treated via a conventional pulpotomy tech- nique were randomly assigned to the MTA group (33 teeth)

Gideon Holan; Eliezer Eidelman; Anna B. Fuks

2005-01-01

129

A Comparison of Four Pulpotomy Techniques in Primary Molars: A Long-term Follow-up  

Microsoft Academic Search

The study evaluated the effects of formocresol (FC), ferric sulphate (FS), calcium hydroxide (Ca[OH]2), and mineral trioxide aggregate (MTA) as pulp dressing agents in pulpotomized primary molars. Sixteen children each with at least four primary molars requiring pulpotomy were selected. Eighty selected teeth were divided into four groups and treated with one of the pulpotomy agent. The children were recalled

Deniz Sonmez; Saziye Sari; Tu?ba Çetinba?

2008-01-01

130

Mineral trioxide aggregate vs. formocresol in pulpotomized primary molars: a preliminary report  

Microsoft Academic Search

Purpose: The aim of this study was to compare the effect of mineral trioxide aggregate (MTA) to that of formocresol (FC) as pulp dressing agents in pulpotomized primary molars with cari- ous pulp exposure. Methods: Forty-five primary molars of 26 children were treated by a conventional pulpotomy technique. The teeth were randomly assigned to the MTA (experimental) or FC (control)

Eliezer Eidelman; Anna B. Fuks

2001-01-01

131

Maxillary tuberosity fracture associated with first molar extraction: a case report.  

PubMed

Maxillary tuberosity fractures during molar teeth extraction can occur commonly in dental practice; however, very few cases are reported and discussed in the literature. This article presents a case of large fracture of maxillary tuberosity during extraction of first maxillary molar tooth and its conservative treatment outcomes. PMID:19212477

Polat, Hidayet B; Ay, Sinan; Kara, M Isa

2007-10-01

132

Uniquely derived upper molar morphology of Eocene Amphipithecidae (Primates: Anthropoidea): homology and phylogeny.  

PubMed

The extinct Southeast Asian primate family Amphipithecidae is regularly cited in discussions of anthropoid origins, but its phylogenetic position remains controversial. In part, the lack of consensus regarding amphipithecid relationships can be attributed to uncertainty regarding the homology of upper molar structures in this group. Here, we describe a virtually pristine upper molar of Pondaungia cotteri from the late middle Eocene Pondaung Formation of Myanmar, which is the first example of a relatively unworn and well-preserved amphipithecid upper molar ever recovered. The distolingual upper molar cusp in this new specimen of Pondaungia appears to be a lingually displaced and enlarged metaconule, rather than a hypocone or pseudohypocone as previous workers have thought. Reassessment of the upper molar morphology of other amphipithecids and putative amphipithecids reveals a very similar pattern in Siamopithecus, Myanmarpithecus and Ganlea, all of which are interpreted as having upper molars showing many of the same derived features apparent in Pondaungia. In contrast, the upper molar morphology of Bugtipithecus diverges radically from that of undoubted amphipithecids, and the latter taxon is excluded from Amphipithecidae on this basis. Phylogenetic analyses of several character-taxon matrices culled from the recent literature and updated to reflect the new information on amphipithecid upper molar morphology yield similar results. Consensus tree topologies derived from these analyses support amphipithecid monophyly and stable relationships within Amphipithecidae. Amphipithecids appear to be stem members of the anthropoid clade. PMID:23823753

Coster, Pauline; Beard, K Christopher; Soe, Aung Naing; Sein, Chit; Chaimanee, Yaowalak; Lazzari, Vincent; Valentin, Xavier; Jaeger, Jean-Jacques

2013-08-01

133

Experience versus complication rate in third molar surgery  

PubMed Central

Objectives The records of 1087 patients who underwent surgical removal of third molar teeth were prospectively examined to analyse the possible relationship between postoperative complications and the surgeon's experience parameter. Method and materials Seven surgeons (three specialists in surgical dentistry [specialists SD] and four oral and maxillofacial Senior House Officers [OMFS residents]) carried out the surgical procedures. For each patient, several variables were recorded including age, gender, radiographic position of extracted teeth, treating surgeon, duration of surgery and postoperative complications. Results Analysis of the data revealed some differences in the incidence of complications produced by the specialists SD and OMFS residents. The main statistically relevant differences were increase the incidences of trismus, nerve paraesthesia, alveolar osteitis and infection in the resident-treated group, while the specialist-treated group showed higher rates of post-operative bleeding. Conclusion The higher rate of postoperative complications in the resident-treated group suggests that at least some of the complications might be related to surgical experience. Further work needs to compare specialists of training programmes with different years of experience, using large cross – sectional studies.

Jerjes, Waseem; El-Maaytah, Mohammed; Swinson, Brian; Banu, Bilquis; Upile, Tahwinder; D'Sa, Sapna; Al-Khawalde, Mohammed; Chaib, Boussad; Hopper, Colin

2006-01-01

134

Lingual nerve protection during surgical removal of lower third molars. a prospective randomised study.  

PubMed

A prospective randomised study was designed to evaluate the efficacy of protecting the lingual nerve by subperiosteal insertion of a retractor in 300 patients. All operations were performed under local anaesthesia and only one molar was removed at a time. In one group, the lower third molar was removed with protection of the lingual nerve and in another group, without protection. Molars which did not need to be sectioned were excluded from the study. The position of the molar, the degree of surgical difficulty and patient gender and age were also recorded. The results indicate 1.33% incidence of temporary lingual nerve dysaesthesia--this being low in comparison with other studies. No permanent disturbances were found. The intergroup percentage difference was not significant. It is suggested that routine application of a lingual protecting instrument during surgical removal of a third molar is not necessary in the hands of an experienced surgeon. PMID:11030397

Gargallo-Albiol, J; Buenechea-Imaz, R; Gay-Escoda, C

2000-08-01

135

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

136

Influence of third molars in Le Fort 1 osteotomy  

PubMed Central

Background: The influence of maxillary third molar (M3) on the outcomes of Le Fort 1 osteotomy is not deeply investigated. Aim: To investigate the influence of M3 on Le Fort 1 osteotomies. Setting: Tertiary Referral Center, operated by a single surgeon, prospective study. Period: January 2005 to December 2010. Patients: Consecutive Le Fort 1 osteotomy patients with both M3. Predictor Variable: Gender, position, M3 root morphology, and degree of impaction. Outcome Variable: Time taken after all osteotomy cuts to point of time when maxilla is placed in predetermined plane. Result: A total of 658 M3 in line of cut were studied. Of all M3, 312 were impacted, 28.9% were partially impacted and 23.7% were erupted. Of all the M3, 2.9% had their cuspal tips above the horizontal cut, 13.8% along the line of cut, and in 20.7% below the line but not erupted. Buccoverted tooth took shortest time (7.74 minutes), while palatoversion required more time (8.44 minutes) (P = 0.000). When the cuspal tip of M3 was located above the horizontal line of cut, the mean time required to achieve the planned position was 7 minutes, while the completely erupted teeth took a mean of 8.24 minutes (P = 0.000). Conclusion: When the M3 is placed higher, it takes lesser time to prepare basal bone to receive the maxilla at its predetermined level. Angulation of M3 influences the outcome. Deeply placed M3 reduces the manipulation of the greater pterygoid palatine vessels in the area thereby minimizing the bleeding in the surgical field.

Balaji, S. M.

2011-01-01

137

Use of cone beam imaging to assess inter-root distance in molar furcations.  

PubMed

This study used cone beam computed tomography (CBCT) to evaluate distances among root surfaces in molar furcations and assess the congruence between inter-root distances in molar furcations and curette blade widths. Distances among root surfaces at 1 and 3 mm from the fornix of molar furcations (points A and B, respectively) were measured with standardized CBCT images and analyzed using computer software. Periodontal curette widths were evaluated by digital caliper and stereomicroscope (magnification 10x). Forty CBCT images (containing a total of 141 molar teeth and 354 furcations) were evaluated; 19 furcations (5.4%) with fused molars were excluded. Mesial furcations of the first molars had the highest average inter-root distances (point A: 3.81 ± 0.87 mm; point B: 5.30 ± 0.92 mm), while buccal furcations of the maxillary second molars had the smallest average distances (point A: 1.49 ± 0.37 mm; point B: 1.90 ± 0.65 mm). Analysis of 107 curettes revealed statistically significant differences among curette types and manufacturers. Pearson's coefficient revealed a strong and significant correlation for curette measurement using digital caliper and stereomicroscope (r = 0.86, P < 0.01). In most cases, the curettes tested allowed access for scaling and root planing of teeth with furcation involvement. PMID:24598502

Dutra, Danilo Antonio Milbradt; da Silva, Felipe Borges; Moreira, Carlos Heitor Cunha; Kantorski, Karla Zanini

2014-01-01

138

Autogenous transplantation of mandibular third molar to replace tooth with vertical root fracture  

PubMed Central

Autogenous tooth transplantation (ATT) can be considered when there is a hopeless molar tooth and suitable donor present. This report presents an unconventional case of successful ATT of a third molar replacing the adjacent fractured second molar in a 33 year old woman. This wisdom tooth had completely developed roots. Root-end filling with Calcium Enriched Mixture (CEM) cement was performed in the third molar. The second molar was extracted non-traumatically without any bone removal; the wisdom tooth was immediately transplanted into the recipient socket. No endodontic treatment was carried out either during or after the ATT. At six-month and 2-year clinical examination the patient was asymptomatic; the transplanted tooth was still functional, with no evidence of marginal periodontal pathosis. At the same follow ups, radiographic evaluation illustrated bone regeneration, normal PDL, and absence of external root resorption. Transplantation of mature third molar seems to be a promising method for replacing a lost permanent molar tooth and restoring aesthetics and function.

Asgary, Saeed

2009-01-01

139

Autogenous transplantation of mandibular third molar to replace tooth with vertical root fracture.  

PubMed

Autogenous tooth transplantation (ATT) can be considered when there is a hopeless molar tooth and suitable donor present. This report presents an unconventional case of successful ATT of a third molar replacing the adjacent fractured second molar in a 33 year old woman. This wisdom tooth had completely developed roots. Root-end filling with Calcium Enriched Mixture (CEM) cement was performed in the third molar. The second molar was extracted non-traumatically without any bone removal; the wisdom tooth was immediately transplanted into the recipient socket. No endodontic treatment was carried out either during or after the ATT. At six-month and 2-year clinical examination the patient was asymptomatic; the transplanted tooth was still functional, with no evidence of marginal periodontal pathosis. At the same follow ups, radiographic evaluation illustrated bone regeneration, normal PDL, and absence of external root resorption. Transplantation of mature third molar seems to be a promising method for replacing a lost permanent molar tooth and restoring aesthetics and function. PMID:24003333

Asgary, Saeed

2009-01-01

140

Prevalence of taurodontism in primary mandibular first molars of ethnic Indian children.  

PubMed

The objective of this study was to determine the prevalence of taurodontism in primary mandibular first molars in ethnic Indian children using periapical radiographs. Periapical radiographs of 274 children obtained from December 2008 to August 2010 were retrospectively screened and examined. Radiographs of 196 patients (99 boys and 97 girls; ages 2.5-10.5) with bilateral primary mandibular first molars were randomly selected and evaluated. The gender, symmetry, and frequencies of occurrence of taurodont primary mandibular first molars were compared and the obtained data were statistically analyzed using the x2 test. Eight (4.08%) taurodont primary mandibular first molars were found with a bilateral incidence of a symmetrical distribution of 38% (3/8). The prevalence of taurodontism in primary mandibular first molars did not differ significantly between right and left sides or with gender (P ? 0.05). The results of the present study indicate that approximately 4% of Indian children had taurodontism in primary mandibular first molars. Clinicians should be aware of the prevalence of this anatomic variant in primary mandibular first molars among the Indian population for early identification of taurodonts and for rendering the best care during dental treatment. PMID:23032243

Nagaveni, N B; Radhika, N B

2012-01-01

141

Piezoelectric bone surgery in the treatment of an osteoma associated with an impacted inferior third molar: a case report  

PubMed Central

Summary Operative removal of impacted mandibular third molars is a common and not riskless surgical procedure. We present an emblematic case of an osteoma closely associated with an impacted third left mandibular molar treated by Mectron Piezosurgery medical ultrasonic device.

D'Amato, Salvatore; Sgaramella, Nicola; Vanore, Laura; Piombino, Pasquale; Orabona, Giovanni Dell'Aversana; Santagata, Mario

2014-01-01

142

Two-Rooted Maxillary First Molars with Two Canals: A Case Series  

PubMed Central

Thorough understanding of the anatomic and internal morphology of a root canal system is absolutely essential for the success of endodontic treatment. Since permanent maxillary first molars have shown variation in internal anatomy, morphology, this tooth has been reviewed extensively. Presence of two canals in a two-rooted maxillary first molar has rarely been reported in studies describing tooth and root canal anatomies. In this report, three cases are presented, which involve the root canal treatment of maxillary first molars with fusion of the two buccal roots.

Shakouie, Sahar; Mokhtari, Hadi; Ghasemi, Negin; Gholizadeh, Seddigheh

2013-01-01

143

Ectopic eruption of maxillary first permanent molars in children with cleft lip.  

PubMed

The purpose of this study was to determine the incidence of ectopic eruption of the maxillary first permanent molars in cleft patients. Panoramic radiographs of 70 Brazilian Caucasian children, 6 to 8 years old and with complete unilateral cleft lip and alveolus, were assessed. Fourteen of 70 patients (20%) presented with ectopic eruption of one or both maxillary first permanent molars. Sixteen of 19 ectopically erupted molars (85%) were of a reversible type of ectopic eruption and 3 (15%) were irreversible. No significant differences were found between sexes or between cleft sides. PMID:8893107

da Silva Filho, O G; De Albuquerque, M V; Kurol, J

1996-01-01

144

Vital Pulp Therapy with Three Different Pulpotomy Agents in Immature Molars: A Case Report  

PubMed Central

Introduction This case report describes apexogenesis treatment of three molar teeth of an 8-year-old boy using three different pulpotomy agents. Methods Pulpotomy was performed on decayed immature molar teeth with established irreversible pulpitis and the remaining pulp was capped with either zinc oxide eugenol, ProRoot mineral trioxide aggregate or calcium-enriched mixture (CEM) cement. Teeth were restored with stainless steel crowns. Results Eighteen months clinical and radiographic follow-up revealed successful preservation of pulpal vitality with continued root development in all treated teeth. Conclusion Based on this case report, CEM cement may be an alternative option for pulpotomy treatment of immature permanent molars.

Harandi, Azadeh; Forghani, Maryam; Ghoddusi, Jamileh

2013-01-01

145

Extraction of upper first molar resulting in fracture of maxillary tuberosity.  

PubMed

Fracture of the maxillary tuberosity sometimes can happen when pneumatization of the maxillary sinus extends between the roots of upper molars. Some factors may lead to this complication including prominent or curved roots, chronic periapical infection, hypercementosis, root ankylosis and tooth fusion. This paper reports a case with fracture of the maxillary tuberosity following extraction of an upper first molar in general dental practice. Prevention from any complication during extractions of maxillary molars with large antral enlargement is possible with careful preoperative examination and accurate surgical planning. The general dentist should be prepared to refer such cases to an oral surgeon when facing difficulties like the presented case. PMID:19208000

Altu?, Hasan Ayberk; Sahin, Sermet; Sencimen, Metin; Dogan, Necdet

2009-02-01

146

Removal of a Maxillary Third Molar Displaced into Pterygopalatine Fossa via Intraoral Approach.  

PubMed

The removal of impacted maxillary third molars is one of the most common procedures performed in oral and maxillofacial surgery units with low rates of complications and morbidity. A few cases of accidental displacement of third molars into adjacent anatomical spaces, such as the infratemporal fossa, the pterygomandibular space, the maxillary sinus, buccal space, or the lateral pharyngeal space, during surgical interventions have been reported. In this paper, a case of a maxillary third molar accidentally displaced into the pterygopalatine fossa is presented, and the removal of the tooth via intraoral approach is described. PMID:23476814

Ozer, Nedim; Uçem, Fulya; Saruhano?lu, Alp; Yilmaz, Serdar; Tanyeri, Hakk?

2013-01-01

147

Removal of a Maxillary Third Molar Displaced into Pterygopalatine Fossa via Intraoral Approach  

PubMed Central

The removal of impacted maxillary third molars is one of the most common procedures performed in oral and maxillofacial surgery units with low rates of complications and morbidity. A few cases of accidental displacement of third molars into adjacent anatomical spaces, such as the infratemporal fossa, the pterygomandibular space, the maxillary sinus, buccal space, or the lateral pharyngeal space, during surgical interventions have been reported. In this paper, a case of a maxillary third molar accidentally displaced into the pterygopalatine fossa is presented, and the removal of the tooth via intraoral approach is described.

Ozer, Nedim; Ucem, Fulya; Saruhanoglu, Alp; Yilmaz, Serdar; Tanyeri, Hakk?

2013-01-01

148

Radiographic evaluation of third molar genesis in Greek orthodontic patients  

PubMed Central

Objectives The study reported here investigated the first radiographic evidence of third molar (M3) formation, their incidence and distribution as well as their congenital absence on the right or the left side in either the maxilla or the mandible, in both male and female Greek orthodontic patients. Materials and methods A total of 618 panoramic radiographs were initially examined. After the application of inclusion/exclusion criteria, the group finally selected consisted of 428 patients (mean age 11.64 years, range 5–18): 179 males (mean age 11.73 ± 2.46) and 249 females (mean age 11.57 ± 2.45). The collected data were analyzed using SPSS software (IBM, Armonk, New York, NY, USA). The level of significance for all analyses was set to p = 0.05. The chi-square (?2) test was used to assess the relationships between variables. The Wilcoxon’s signed-rank test and the Mann-Whitney U test were also used for comparisons as well as the Spearman’s rho test for correlations. Results M3s were first detected in females at the age of 7 years whereas males followed one year later at the age of 8 years. A strong correlation between age and M3 development was revealed for both sexes (Spearman’s rho = 0.177, p = 0.05). Presence of all four M3s was the most common incidence (present in 70.8% of study subjects), followed by the agenesis of two (12.1%), agenesis of all four (8.4%), one (6.8%), and three (1.9%) M3s. Congenitally missing M3s in all subjects showed a significantly greater predilection for the maxilla over the mandible (19.6% and 15.5%, respectively) (Wilcoxon signed-rank test Z = ?2.404, p = 0.016). However, the distribution was found equal between the two sides of the jaws. The difference between the absent frequencies of M3s in the mandible and the maxilla was found statistically significant for the total sample (McNemar’s test, p < 0.001) and for males (p = 0.041) as well. Conclusion The study data may provide a reference for the M3 genesis in Greeks.

Barka, Georgia; Marathiotis, Konstantinos; Protogerakis, Michael; Zafeiriadis, Andreas

2013-01-01

149

Accessory roots in maxillary molar teeth: a review and endodontic considerations.  

PubMed

Maxillary molar teeth may have accessory roots. The aim of this paper is to review and discuss the endodontic implications of this anatomical variation. A review of the literature was undertaken to identify studies and reported cases where accessory roots have been recorded in maxillary molar teeth. The results show that although the prevalence of accessory roots in maxillary molar teeth is low, they can exist in all three types of maxillary molar teeth, and they may be located palatally, buccally, mesially or distally. Hence, it is essential that dentists undertaking root canal treatment thoroughly assess all teeth to determine how many roots are present in order to provide the best possible outcome of treatment for the patient. PMID:22624750

Ahmed, H M A; Abbott, P V

2012-06-01

150

Root Canal Morphology of Mandibular First Permanent Molars in an Indian Population  

PubMed Central

An in vitro study was performed to determine the number of roots, root canals per tooth, root canal configurations, and frequency of isthmi and apical deltas in mandibular first permanent molars in an Indian population. Hundred and fifty mandibular first permanent molars were collected and subjected to clearing technique. The cleared teeth were examined in a stereomicroscope under 7.5x magnifications. The canal configurations were categorized using Vertucci's classification. Overall 94.6% of the mandibular first molars had two roots, and 5.3% had extradistal roots (distolingual root). In addition, 64% of the specimens had three root canals, and 36% had four root canals. The most common canal configurations of mesial and distal roots were Vertucci type IV (54%) and type I (65.3%), respectively. Clinician should be aware of the complex root canal morphology of mandibular first molars among the Indian population before and during the root canal treatment.

Chourasia, Hemant Ramesh; Meshram, Ganesh K.; Warhadpande, Manjusha; Dakshindas, Darshan

2012-01-01

151

How Many Digits Should We Use in Formula or Molar Mass Calculations?  

ERIC Educational Resources Information Center

The calculations of uncertainties in the formula or molar masses of compounds are streamlined. Three rules of increasing complexity are proposed, which overestimate the uncertainty so there is little if any risk that the true values are missed.

Svensson, Christer

2004-01-01

152

Effects of ozone therapy on pain, swelling, and trismus following third molar surgery.  

PubMed

The aim of this study was to evaluate the efficacy of therapeutic ozone application in the management of pain, swelling, and trismus associated with the surgical removal of impacted mandibular third molars. Sixty consecutive patients with asymptomatic bilateral impacted mandibular third molars were recruited into the study. Randomly, by use of envelops, the molar on one side was extracted and ozone therapy was given (study side); the molar on the other side was extracted 2 weeks later and sham ozone therapy was given (negative control side). The mean age of the 60 patients was 22.6±2.3 years (range 18-25 years). No differences were found between the two sides for mouth opening or swelling. The degree of pain and the number of analgesic tablets taken was significantly lower for the study side. This study showed ozone therapy to have a positive effect on OHIP-14 questionnaire results. PMID:24332588

Kazancioglu, H O; Kurklu, E; Ezirganli, S

2014-05-01

153

Simplifying Chemical Reactor Design by using Molar Quantities Instead of Fractional Conversion.  

ERIC Educational Resources Information Center

Explains the advantages of using molar quantities in chemical reactor design. Advocates the use of differential versions of reactor mass balances rather than the integrated forms. Provides specific examples and cases to illustrate the principles. (ML)

Brown, Lee F.; Falconer, John L.

1987-01-01

154

Alkaline phosphatase activity in sequential mouse molar tooth development an electron microscopic study  

Microsoft Academic Search

First molar teeth of developing Swiss albino mice were studied for alkaline phosphatase activity. Specimens ranging from 19 days in utero to 8 days postnatal were used (prebell through appositional and mineralization stages).

Edward P. Leonard; D. Vincent Provenza

1973-01-01

155

Root Canal Morphology of Human Mandibular First Permanent Molars in an Iranian Population  

PubMed Central

Background and aims The knowledge of variations in root canal morphology is critical for a successful endodontic treatment. The purpose of this study was to investigate variations in the root canal system of human mandibular first permanent molars in an Iranian population. Materials and methods In this study, 209 mandibular first molar teeth were decalcified, dye-injected, and cleared in order to determine the number and configuration of the root canals. Results The results demonstrated that 65.56% of the mandibular first molars under study had three, 31.57% had four and 2.87% had two canals. Conclusion According to the results of this study and considering variations in the root canal systems of the mandibular first molars, it seems that great care should be taken in the root canal treatment of these teeth.

Shahi, Shahriar; Yavari, Hamid Reza; Rahimi, Saeed; Torkamani, Reza

2008-01-01

156

Root Canal Configuration of Maxillary First Permanent Molars in an Iranian Population  

PubMed Central

Background and aims It is critical to have a proper knowledge of the normal anatomy of the pulp and its variations for the success of endodontic treatment. The purpose of this study was to investigate variations in the root canal system of maxillary first permanent molars in an Iranian population. Materials and methods In this study, 137 maxillary first molars were decalcified, dye-injected, cleared and studied. Results The results demonstrated that 37.96% of the maxillary first molars under study had three canals, 58.4% had four canals and 3.64% had five canals. Conclusion According to the results of this study and considering variations in the root canal systems of maxillary first molars, it seems that great care should be taken in the root canal treatment of these teeth.

Shahi, Shahriar; Yavari, Hamid Reza; Rahimi, Saeed; Ahmadi, Ali

2007-01-01

157

Class, type and position of 9148 surgically removed third molars in 3206 patients: A retrospective study  

PubMed Central

Objective: To investigate the class, type, position, diagnosis and most common procedures used in the surgical removal of third molars, and evaluate the sex and age distribution in a representative sample of Mexican patients. Study Design: A retrospective descriptive study was made covering the period 1993-2008 in relation to 9148 extracted third molars in 3206 patients treated in the Dental School of Salle Bajío University, A.C. (Mexico). Patients of either sex and aged 11-59 years, with at least one third molar programmed for surgical removal, were included in the study. A descriptive statistical study was made. Results: The mean patient age was 27.6 ± 10.6 years. There were 2093 females (65.3%) and 1111 males (34.6%). In relation to the 4025 upper molars, extraction was decided for prophylactic reasons in 3827 cases (95.08%). Type A presentations were recorded in 1929 cases (47.9%), with a vertical position in 1931 teeth (48%). In relation to the 5123 lower third molars, extraction was likewise most often indicated for prophylactic reasons (4424 cases, 86.36%). A total of 2353 teeth corresponded to type A (45.9%), 2545 were class I cases (49.7%), and a mesioangular position was observed in 1850 cases (36.1%). Conclusions: The present study shows that in Mexican patients, upper third molars most often correspond to type A and class I, with a vertical position, while lower third molars predominantly correspond to type A and class I, with a mesioangular position. This information can help dental surgeons take better decisions before and after surgery, to the benefit of their patients. Key words:Third molars, retrospective review, surgical removal.

Rocha-Navarro, Miriam L.; Acosta-Veloz, Anselmo L.; Juarez-Hernandez, Angelica

2012-01-01

158

Maxillary tuberosity fracture and subconjunctival hemorrhage following extraction of maxillary third molar  

PubMed Central

Extraction of teeth is the most common minor surgical procedure performed. Complication of extraction ranges from periodontal injury to fracture of jaw in the mandible and fracture of tuberosity and oroantral communication in the maxilla. Subconjunctival hemorrhage after extraction of maxillary molar is a very rare complication, and so far, only one case is reported in the literature. We report a case of subconjunctival hemorrhage with maxillary tuberosity fracture after maxillary third molar extraction.

Thirumurugan, Kanagasabapathy; Munzanoor, Rathinam Ramesh Babu; Prasad, Gnanasekaran Arun; Sankar, Kannan

2013-01-01

159

Investigation on the utility of permanent maxillary molar cusp areas for sex estimation  

Microsoft Academic Search

Digital photogrammetric methods were employed to assess the level of sexual dimorphism present in permanent maxillary molar\\u000a cusp areas of black South Africans (130 males, 105 females). Odontometric standards were then developed for diagnosing sex,\\u000a based on the cusp area data derived for these teeth. Results demonstrated that all cusp area measurements of both the first\\u000a and second maxillary molars

P. James Macaluso Jr

2011-01-01

160

Thermochemical studies for determination of the molar enthalpy of formation of aniline derivatives  

Microsoft Academic Search

The standard (po=0.1 MPa) molar enthalpies of combustion atT=298.15 K were measured by static bomb combustion calorimetry for liquidN,N-diethylaniline,N,N-dimethyl-m-toluidine,N,N-dimethyl-p-toluidine, andN-ethyl-m-toluidine. Vaporization enthalpies forN,N-dimethyl-m-toluidine andN-ethyl-m-toluidine were determined by correlation gas chromatography. Derived standard molar values of ?fH

Manuel A. V. Ribeiro da Silva; Maria Dores M. C. Ribeiro da Silva; Maria Fatima B. M. Monteiro; Maria Luísa A. C. N. Gomes; James S. Chickos; Anjanette P. Smith; Joel F. Liebman

1996-01-01

161

Molar conductivity calculation of Li-ion battery electrolyte based on mode coupling theory.  

PubMed

A method is proposed to calculate molar conductivity based on mode coupling theory in which the ion transference number is introduced into the theory. The molar conductivities of LiPF6, LiClO4, LiBF4, LiAsF6 in PC (propylene carbonate) are calculated based on this method. The results fit well to the literature data. This presents a potential way to calculate the conductivities of Li-ion battery electrolytes. PMID:16392907

Pu, Weihua; He, Xiangming; Lu, Jiufang; Jiang, Changyin; Wan, Chunrong

2005-12-15

162

IRON (III) MOLAR EXTINCTION COEFFICIENTS IN LIGHT AND HEAVY WATER SOLUTIONS  

Microsoft Academic Search

The iron(III) molar extinction coefficient in HâO-0.4 M HâSO\\/; sub 4\\/ solution at maximum absorption and 25 deg C, epsilon \\/sub s\\/, was ; determined to be 2220 plus or minus 20 liters mole⁻¹ cm⁻¹. The ; ratio of the iron(III) molar extinction coefficient in DâO-0.4 M HâSO\\/; sub 4\\/ solution at maximum absorption and 25 deg C to epsilon

J. W. Boyle; H. A. Mahlman

1962-01-01

163

A method for the determination of the molar extinction coefficient of structure-linked chromophores  

Microsoft Academic Search

Synopsis  This paper describes a general method for the determination of the molar extinction ceefficient of a chromophore covalently bound to structure-linked groups, without isolating the compound formed. The method is illustrated by the determination of the molar extinction coefficient of the reaction product of 2,4-dinitro-1-fluorobenzene (DNFB) with films of aminoethyl-cellulose (AE-cellulose). The method is based on the relation between the

J. P. R. Van Dalen; W. B. A. M. Ahsmann; P. Van Duijn

1970-01-01

164

Mandibular molar root morphology in Neanderthals and Late Pleistocene and recent Homo sapiens.  

PubMed

Neanderthals have a distinctive suite of dental features, including large anterior crown and root dimensions and molars with enlarged pulp cavities. Yet, there is little known about variation in molar root morphology in Neanderthals and other recent and fossil members of Homo. Here, we provide the first comprehensive metric analysis of permanent mandibular molar root morphology in Middle and Late Pleistocene Homo neanderthalensis, and Late Pleistocene (Aterian) and recent Homo sapiens. We specifically address the question of whether root form can be used to distinguish between these groups and assess whether any variation in root form can be related to differences in tooth function. We apply a microtomographic imaging approach to visualise and quantify the external and internal dental morphologies of both isolated molars and molars embedded in the mandible (n=127). Univariate and multivariate analyses reveal both similarities (root length and pulp volume) and differences (occurrence of pyramidal roots and dental tissue volume proportion) in molar root morphology among penecontemporaneous Neanderthals and Aterian H. sapiens. In contrast, the molars of recent H. sapiens are markedly smaller than both Pleistocene H. sapiens and Neanderthals, but share with the former the dentine volume reduction and a smaller root-to-crown volume compared with Neanderthals. Furthermore, we found the first molar to have the largest average root surface area in recent H. sapiens and Neanderthals, although in the latter the difference between M(1) and M(2) is small. In contrast, Aterian H. sapiens root surface areas peak at M(2). Since root surface area is linked to masticatory function, this suggests a distinct occlusal loading regime in Neanderthals compared with both recent and Pleistocene H. sapiens. PMID:20719359

Kupczik, Kornelius; Hublin, Jean-Jacques

2010-11-01

165

Maxillary tuberosity fracture and subconjunctival hemorrhage following extraction of maxillary third molar.  

PubMed

Extraction of teeth is the most common minor surgical procedure performed. Complication of extraction ranges from periodontal injury to fracture of jaw in the mandible and fracture of tuberosity and oroantral communication in the maxilla. Subconjunctival hemorrhage after extraction of maxillary molar is a very rare complication, and so far, only one case is reported in the literature. We report a case of subconjunctival hemorrhage with maxillary tuberosity fracture after maxillary third molar extraction. PMID:23633874

Thirumurugan, Kanagasabapathy; Munzanoor, Rathinam Ramesh Babu; Prasad, Gnanasekaran Arun; Sankar, Kannan

2013-01-01

166

Effects of parathyroid hormone on odontogenesis of the mouse embryonic molar tooth In vitro  

Microsoft Academic Search

Summary  Mandibular first molars of 17-day-old mouse embryos were culturedin vitro to examine the histological effects of various concentrations of parathyroid hormone (PTH) on odontogenesis of the molars.\\u000a PTH did not affect the cytodifferentiation of mesenchymal cells into preodontoblasts but inhibited that of preodontoblasts\\u000a into odontoblasts. Consequently, the odontoblasts failed to undergo dentinogenesis. On the other hand, inner enamel epithelium\\u000a achieved

Y. Sakakura

1987-01-01

167

Mandibular first and second molar. The variability of roots and root canal system.  

PubMed

The root and canal anatomy of mandibular first and second molars has normally recurring features, as well as a great number of atypias. Normally mandibular first and second molars have two roots, one is mesial and the other is distal, and at least three main canals. The roots of the second molar can change from one to three, the first molar can have also four roots; the canals can change from three to even six. The conventional root canal anatomy indicates the location of the initial access. The knowledge of both the normal and abnormal anatomy of molars shows the parameters under which root canal therapy is to be executed and can directly modify the probability of success. This is the reason why endodontists must be familiar with all abnormalities as well as their percentage. We present a review of the modern literature about the event of aberrances with references to the number and morphology in mandibular first and second molar root and root canals. PMID:9835748

Maggiore, C; Gallottini, L; Resi, J P

1998-09-01

168

Sharp mandibular bone irregularities after lower third molar extraction: Incidence, clinical features and risk factors  

PubMed Central

Objectives: The purpose of this study was to determine the incidence and clinical symptoms associated with sharp mandibular bone irregularities (SMBI) after lower third molar extraction and to identify possible risk factors for this complication. Study Design: A mixed study design was used. A retrospective cohort study of 1432 lower third molar extractions was done to determine the incidence of SMBI and a retrospective case-control study was done to determine potential demographic and etiologic factors by comparing those patients with postoperative SMBI with controls. Results: Twelve SMBI were found (0.84%). Age was the most important risk factor for this complication. The operated side and the presence of an associated radiolucent image were also significantly related to the development of mandibular bone irregularities. The depth of impaction of the tooth might also be an important factor since erupted or nearly erupted third molars were more frequent in the SMBI group. Conclusions: SMBI are a rare postoperative complication after lower third molar removal. Older patients having left side lower third molars removed are more likely to develop this problem. The treatment should be the removal of the irregularity when the patient is symptomatic. Key words:Third molar, postoperative complication, bone irregularities, age.

Alves-Pereira, Daniela; Valmaseda-Castellon, Eduard; Laskin, Daniel M.; Berini-Aytes, Leonardo; Gay-Escoda, Cosme

2013-01-01

169

Pathological (late) fractures of the mandibular angle after lower third molar removal: a case series  

PubMed Central

Introduction Pathological (late) fracture of the mandibular angle after third molar surgery is very rare (0.005% of third molar removals). There are 94 cases reported in the literature; cases associated with osseous pathologies such as osteomyelitis or any local and systemic diseases that may compromise mandibular bone strength have not been included. We describe three new cases of pathological (late) fracture of the mandibular angle after third molar surgery. Case presentations The first patient was a 27-year-old Caucasian man who had undergone surgical removal of a 3.8, mesioangular variety, class II-C third molar 20 days before admission to our clinic. The fracture of his left mandibular angle, complete and composed, occurred during chewing. The second patient was a 32-year-old Caucasian man. He had undergone surgical removal of a 3.8, mesioangular variety, class II-B third molar 22 days before his admission. The fracture, which occurred during mastication, was studied by computed tomography that showed reparative tissue in the fracture site. The third patient was a 36-year-old Caucasian man who had undergone surgical removal of a 3.8, vertical variety, class II-C third molar 25 days before the observation. In this case the fracture of his mandibular angle was oblique (unfavorable), complete and composed. The fracture had occurred during chewing. We studied the fracture by optical projection tomography and computed tomography. All of the surgical removals of the 3.8 third molars, performed by the patients’ dentists who had more than 10 years of experience, were difficult. We treated the fractures with open surgical reduction, internal fixation by titanium miniplates and intermaxillary elastic fixation removed after 6 weeks. Conclusions The literature indicates that the risk of pathological (late) fracture of the mandibular angle after third molar surgery for total inclusions (class II-III, type C) is twice that of partial inclusions due to the necessity of ostectomies more generous than those for partial inclusions. Other important factors are the anatomy of the teeth and the features of the teeth roots. These fractures predominantly occur in patients who are older than 25 years. The highest incidence (67.8% of cases) is found in the second and third week postsurgery. We emphasize that before the third molar surgery it is extremely important to always provide adequate instructions to the patient in order to avoid early masticatory loads and prevent this rare event.

2013-01-01

170

Compositional dependent partial molar volume and compressibility of CO2 in rhyolite, phonolite and basalt glasses  

NASA Astrophysics Data System (ADS)

Carbon dioxide is the second most abundant volatile in magmatic systems and plays an important role in many magmatic processes, e.g. partial melting, volatile saturation, outgassing. Despite this relevance, the volumetric properties of carbon-bearing silicates at relevant pressure and temperature conditions remain largely unknown because of considerable experimental difficulties associated with in situ measurements. Density and elasticity measurements on quenched glasses can provide an alternative source of information. For dissolved water, such measurements indicate that the partial molar volume is independent of compositions at ambient pressure [1], but the partial molar compressibility is not [2, 3]. Thus the partial molar volume of water may depend on melt composition at elevated pressure. For dissolved CO2, no such data is available. In order to constrain the effect of magma composition on the partial molar volume and compressibility of dissolved carbon, we determined the density and elasticity for three series of carbon-bearing basalt, phonolite and rhyolite glasses, quenched from 3.5 GPa and relaxed at ambient pressure. The CO2 content varies between 0 to 3.90 wt% depending on the glass composition. Glass densities were determined using the sink/float method in a diiodomethane (CH2I2) - acetone mixture. Brillouin measurements were conducted on relaxed and unrelaxed silicate glasses in platelet geometry to determine the compressional (VP) and shear (VS) wave velocities and elastic moduli. The partial molar volume of CO2 in rhyolite, phonolite and basalt glasses is 25.4 ± 0.9, 22.1 ± 0.6 and 26.6 ±1.8 cm3/mol, respectively. Thus, unlike for dissolved water, the partial molar volume of CO2 displays a resolvable compositional effect. Although the composition and CO2/carbonate speciation of the phonolite glasses is intermediate between that of the rhyolite and basalt glasses, the molar volume is not. Similar to dissolved water, the partial molar bulk modulus of CO2 displays a strong compositional effect. If these compositional dependencies persist in the analogue melts, the partial molar volume of dissolved CO2 will depend on melt composition, both at low and elevated pressure. Thus, for CO2-bearing melts, a full quantitative understanding of density dependent magmatic processes, such as crystal fractionation, magma mixing and melt extraction will require in situ measurements for a range of melt compositions. [1] Richet, P. et al., 2000, Contrib Mineral Petrol, 138, 337-347. [2] Malfait et al. 2011, Am. Mineral. 96, 1402-1409. [3] Whittington et al., 2012, Am. Mineral. 97, 455-467.

Lerch, P.; Seifert, R.; Malfait, W. J.; Sanchez-Valle, C.

2012-12-01

171

Binding constants and partial molar volumes of primary alcohols in sodium dodecylsulfate micelles  

SciTech Connect

The densities of methanol, ethanol, 1-propanol, 1-butanol and 1-hexanol were measured in aqueous solutions of sodium dodecylsulfate at 25/sup 0/C. The partial molar volumes of the alcohols at infinite dilution in the aqueous surfactants solutions were calculated and discussed using a mass-action model for the alcohol distribution between the aqueous and the micellar phase. The partial molar volumes of the alcohols in the aqueous and in the micellar phases, and the ratios between the binding constant and the aggregation number, were calculated. The partial molar volume for all the alcohols in micellar phase is 10 cm/sup 3/-mol/sup -1/ smaller than that in octane. This can be related to the strong hydrophilic interaction between the head groups of the alcohol and the micellized surfactant. From the extrapolated values of the distribution constant and the partial molar volumes in the aqueous and micellar phases, the standard partial molar volume of heptanol in micellar solutions was found to decrease with increasing surfactant concentration. The standard free energy of transfer of alcohols from water to micelles was rationalized in terms of hydrophilic and hydrophobic contributions. A model is proposed in which the empty space around each solute is assumed to be the same in the gas and liquid phases, and is used to explain the behavior of micelles in the presence of amphiphilic solutes.

DeLisi, R.; Lizzio, A.; Milioto, S.; Liveri, V.T.

1986-08-01

172

Accuracy of scanography using storage phosphor plate systems and film for assessment of mandibular third molars  

PubMed Central

Objectives The aim of this study was to compare the diagnostic accuracy of two digital photostimulable storage phosphor (PSP) systems and film for assessment of mandibular third molars before surgery. Methods 110 patients were referred to have both their mandibular third molars removed. Each patient underwent a radiographic examination with scanography using either Digora (Soredex, Helsinki, Finland) and film or VistaScan (Dürr Dental, Beitigheim-Bissingen, Germany) and film in a randomized paired design. Two observers examined the following variables on the scanograms: bone coverage, angulation of the tooth in the bone, number of roots, root morphology and the relationship to the mandibular canal. In 75 of the pairs (Digora/film pair = 38 and Vista/film pair = 37) both third molars were eventually removed. During and after surgery the same variables were assessed, which served as reference standard for the radiographic assessments. The Wilcoxon signed-rank test tested differences in accuracy (radiographic compared with surgical findings) between Digora/film and between Vista/film. Results There was no statistically significant difference between the diagnostic accuracy of film and either of the two digital receptors for assessment of mandibular third molars before surgery (P > 0.05), although Digora obtained a higher accuracy than film. Conclusions Scanography is a valuable method for examination of mandibular third molars before removal and the PSP digital receptors in this study were equal to film for this purpose.

Matzen, LH; Christensen, J; Wenzel, A

2011-01-01

173

Anatomical Relationship of Lingual Nerve to the Region of Mandibular Third Molar  

PubMed Central

ABSTRACT Objectives This study evaluated the relationship of the lingual nerve with the adjacent anatomical structures of the mandibular third molar region, influencing the dentist to be aware of the variability of these relationships. Material and Methods Samples of 24 human corpse half-heads were selected and divided according with the presence or absence of the mandibular third molars. The lingual nerve (LN) was explored, showing its run from the oblique line until its crossing with the submandibular gland duct. The measurements along the LN and the adjacent anatomical structures were taken at the retromolar, molar and sublingual region with the use of a digital caliper. Results The distance from the LN and the third molar socket, which represents the horizontal distance of the lingual plate to the nerve, on average, was 4.4 mm (SD 2.4 mm). The distance from the LN and the lingual alveolar rim, which represents the vertical relationship between the nerve and the lingual alveolar rim of the third molar socket, on average, was 16.8 mm (SD 5.7 mm). The LN has a varied topography that leaves it very vulnerable during any procedure executed in this region. Conclusions Unless adequate protection of the lingual nerve is acquired by following an adequate surgical technique, the lingual nerve will always be vulnerable to damage during surgical intervention or manipulation in this region.

de Carvalho Leite Leal Nunes, Carla Maria; de Almeida Lopes, Maria Candida

2013-01-01

174

Studies of the chronological course of third molars eruption in a northern Chinese population.  

PubMed

Dental age estimation is of great importance for individual identification in forensic medicine and many other fields of study. Among them, tooth eruption is a parameter developmental morphology that can be determined by clinical examinations or by dental X-rays. The purpose of present research is to study the chronological course of third molars eruption in a Chinese population and compare that with other ethnic population for age estimation. A total of 1135 conventional orthopantomograms from 506 male and 629 female northern Chinese subjects aged between 11 and 26 years were analyzed. The eruption status of the third molars was assessed using the developmental stages described by Olze et al. Results showed that the third molars 18, 28, 38 and 48 in the stage A showed significant younger average age in males than in females. The Olze's stage A could be used as a reference stage to determine whether a male or female northern Chinese is likely to be equal or above age 16, with 99.6-100% and 97.4-98.1% of correct predictions, respectively. The stage D was found to be a useful marker for diagnosing age under 16 years, with 98.9-100% and 100% of correct predictions in males and females, respectively. There were some significant differences of the chronological course of the third molars eruption in different ethnic groups, which indicated that population-specific standards could enhance the accuracy of forensic age estimation based on third molar eruption. PMID:24907520

Guo, Yu-Cheng; Yan, Chun-Xia; Lin, Xing-Wei; Zhou, Hong; Pan, Feng; Wei, Lai; Tang, Zheng; Liang, Feng; Chen, Teng

2014-09-01

175

Brief communication: possible third molar impactions in the hominid fossil record.  

PubMed

Impacted third molars affect 15%-20% of modern Americans and Western Europeans. In contrast, third molar impactions have not been reported in the early hominid fossil record. It is uncertain whether the lack of reports reflects an absence of impactions or a failure to recognize them. This communication is intended to raise awareness of the possibility of impactions by describing the appearance of impacted teeth and by noting two possible instances of impaction in early hominids. Specifically, the mandibular third molars of the Sterkfontein specimen, STS52b (Australopithecus africanus), and the left maxillary third molar of the Lake Turkana specimen, KNM-WT 17400 (Australopithecus boisei), are positioned in a manner which suggests that they would not have erupted normally. Both specimens also exhibit strong crowding of the anterior dentition, providing further support for the view that these individuals lacked sufficient space for normal eruption of the third molars. Other published reports of dental crowding in the hominid fossil record are noted, and it is suggested that more attention be paid to dental impaction and dental crowding in hominid evolution. PMID:8372939

Gibson, K R; Calcagno, J M

1993-08-01

176

The chronological age estimation of third molar mineralization of Han population in southwestern China.  

PubMed

The purpose of the study was to estimate the chronology of third molar mineralization in Han population of southwestern China and find its unique characteristics so that it would provide a reference in several legal cases like forensic age estimation. The study used Demirjian's staging method to study 2192 orthopantomograms of 984 male and 1208 female subjects aged between 8 and 25 years. The statistical data was analyzed by Student's t test and ANOVA. The conclusions of the study are: (1) The chronological mineralization age of third molars of Han population in Southwestern China is similar to the Turkish and the Japanese, was earlier than the Austrian and Han of South China, but later than the Spanish. (2) The mineralization timing of the third molars between two sides in maxilla or mandible has no significant differences in the same gender group. (3) There is no significant difference in mineralization of third molars between male and female, except for tooth 48 in Demirjian's stage E. (4) The mineralization of third molar in maxilla is earlier than mandible. PMID:24794846

Qing, Maofeng; Qiu, Lihua; Gao, Zhi; Bhandari, Kishor

2014-05-01

177

Molar tooth structures in calcareous nodules, early Neoproterozoic Burovaya Formation, Turukhansk region, Siberia  

NASA Astrophysics Data System (ADS)

Molar tooth structures are abundant in large (1-2 m diameter) carbonate nodules within fine-grained, subtidal carbonates of the early Neoproterozoic (lower Upper Riphean) Burovaya Formation along the Sukhaya Tunguska River, Turukhansk Uplift, northwestern Siberia. Although molar tooth structures are regionally abundant in this unit, here they occur only within the nodules. Stable isotopic compositions of molar-tooth-filling dolomicrospar cements and of thinly bedded dolomicrite within and surrounding the nodules are indistinguishable from one another. The carbon isotopic compositions (mean ?13C=+2.8‰ PDB±0.4) reflect mean average oceanic surface water composition during their formation; the light oxygen isotopic compositions (mean ?18O=-6.4‰ PDB±2.2) are generally similar to those of other little-altered Meso- to Neoproterozoic limestones and dolostones. These molar tooth structures have no features that would support a tectonic origin; they more likely formed through bacterial processes. Carbonate cement filling of these voids occurred soon after their formation, but the mechanism responsible for this carbonate precipitation is currently uncertain. Local restriction of molar tooth structures to early diagenetic nodules suggests that penecontemporaneous lithification was required for the formation, or at least preservation, of these widespread Mesoproterozoic to Neoproterozoic features.

Pope, Michael C.; Bartley, Julie K.; Knoll, Andrew H.; Petrov, Peter Yu.

2003-05-01

178

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

179

Ectopic third molar in the mandibular condyle: A review of the literature  

PubMed Central

Objectives: To evaluate the etiopathogenesis, clinical features, therapeutic options, and surgical approaches for removal of ectopic third molars in the mandibular condyle. Study design: MEDLINE search of articles published on ectopic third molars in the mandibular condyle from 1980 to 2011. 14 well-documented clinical cases from the literature were evaluated together with a new clinical case provided by the authors, representing a sample of 15 patients. Results: We found a mean age at diagnosis of 48.6 years and a higher prevalence in women. In 14 patients, associated radiolucent lesions were diagnosed on radiographic studies and confirmed histopathologically as odontogenic cysts. Clinical symptoms were pain and swelling in the jaw or preauricular region, trismus, difficulty chewing, cutaneous fistula and temporomandibular joint dysfunction. Treatment included conservative management in one case and in the other cases, surgical removal by intra- or extraoral approaches, the latter being the most common approach carried out. In most reported cases, serious complications were not outlined. Conclusions: The etiopathogenic theory involving odontogenic cysts in the displacement of third molars to the mandibular condyle seems to be the most relevant. They must be removed if they cause symptoms or are associated with cystic pathology. The surgical route must be planned according to the location and position of the ectopic third molar, and the possible morbidity associated with surgery. Key words:Third molar, ectopic tooth, condyle, mandible.

Iglesias-Martin, Fernando; Torres-Carranza, Eusebio; Prats-Golczer, Victoria-Eugenia; Garcia-Perla-Garcia, Alberto

2012-01-01

180

A Histologic Study of the Width and Nature of Inter-radicular Spaces in Human Adult Pre-molars and Molars  

Microsoft Academic Search

Serial sections of jaw segments from a human post mortem population of 29 individuals providing 116 posterior interproximal sites were examined at the light microscopic level. Minimum inter-root distances at the locale of closest proximity ranged from more than 4 mm to less than 0.1 mm. They were located in the coronal third of pre-molars and mandibular first and second

P. J. Heins; S. M. Wieder

1986-01-01

181

First permanent molar: first indicator of dental caries activity in initial mixed dentition.  

PubMed

The objective of the present study was to investigate among children in the initial mixed dentition phase the presence of clinical signs that might eventually function as more sensitive indicators of the development of caries disease, denoted here as caries activity. On this basis, we investigated the relationship between salivary levels of mutans streptococci (MS) and decayed, missing and filled permanent and deciduous tooth surfaces (DMFS and dmfs) using microbiological, clinical and radiographic examinations in 81 schoolchildren aged 7-8 years. Whereas dmfs did not present a positive correlation, DMFS was significantly correlated with salivary MS levels. The first permanent molars of the schoolchildren studied comprised 87.3% of the affected surfaces recorded in the DMFS, suggesting that the development of new lesions was preferentially located on the surfaces of the first permanent molars. These results permit us to conclude that the first permanent molars function as first indicators of dental caries activity in the schoolchildren examined. PMID:10863396

Noronha, J C; Massara, M de L; Souki, B Q; Nogueira, A P

1999-01-01

182

Tuning of magnetic properties in cobalt ferrite by varying Fe+2 and Co+2 molar ratios  

NASA Astrophysics Data System (ADS)

Different grades of magnetic cobalt ferrite (CoFe2O4) nanoparticles were synthesized with various molar ratios of Fe+2 to Co+2 ions in the initial salt solutions by the co-precipitation method. The crystal structure and morphology of the nanoparticles are obtained from X-ray diffraction and transmission electron microscopy studies. Fourier transform infrared spectroscopy analysis exhibited the Fe-O stretching vibration ~540 cm-1, confirming the formation of metal oxide. The magnetic studies demonstrate that all of the nanoparticles are superparamagnetic at 300 K. The saturation magnetization and coercivity of the CoFe2O4 nanoparticles are affected by the molar ratios of Fe+2 to Co+2 ions. Among all the synthesized nanoparticles, the system with 75:25 molar ratio of Fe+2 to Co+2 ions with a particle size of 13 nm showed a high magnetization of 90 emu/g.

Biswal, Dipti; Peeples, Brianna N.; Peeples, Caryn; Pradhan, Aswini K.

2013-11-01

183

Asymmetry in mesial root number and morphology in mandibular second molars: a case report  

PubMed Central

Ambiguity in the root morphology of the mandibular second molars is quite common. The most common root canal configuration is 2 roots and 3 canals, nonetheless other possibilities may still exist. The presence of accessory roots is an interesting example of anatomic root variation. While the presence of radix entomolaris or radix paramolaris is regarded as a typical clinical finding of a three-rooted mandibular second permanent molar, the occurrence of an additional mesial root is rather uncommon and represents a possibility of deviation from the regular norms. This case report describes successful endodontic management of a three-rooted mandibular second molar presenting with an unusual accessory mesial root, which was identified with the aid of multiangled radiographs and cone-beam computed tomography imaging. This article also discusses the prevalence, etiology, morphological variations, clinical approach to diagnosis, and significance of supernumerary roots in contemporary clinical dentistry.

Shetty, Shashit; Shekhar, Rhitu

2014-01-01

184

Lingual nerve injury after third molar removal: Unilateral atrophy of fungiform papillae  

PubMed Central

Background: Pain and sensory changes due to lingual nerve injury are one of the most common alterations that follow surgical removal of third molar. They are usually transient but other less common complications, such as the atrophy of fungiform papillae, have an uncertain prognosis. Case Description: We report a case of a 34-year-old woman who presented a unilateral lingual atrophy of fungiform papillae after third molar extraction accompanied by severe dysesthesia that altered her daily life significantly during the following months and how this complication evolved over time. We conducted a literature review on the different factors that can lead to a lingual nerve injury. Clinical Implications: The clinical evolution of temporary and permanent somatosensitve injuries is an important fact to take into consideration during the postoperative management because it will indicate the lesion prognosis. Key words:Lingual nerve, third molar removal, somatosensitive alteration, papillae atrophy, permanent injury, temporary injury.

de-Pablo-Garcia-Cuenca, Alba; Bescos-Atin, Maria S.

2014-01-01

185

Value of Computed Tomography (CT) in Imaging the Morbidity of Submerged Molars: A Case Report  

PubMed Central

Submerged primary molars can be difficult to manage due to the developing dentition. Rarely in some severe cases, may the surgical interventions be required while ensuring the vital structures are protected. Therefore these cases require sophisticated imaging techniques in order to locate the vital structures. In this case report, a 17 year old girl who had a retained and submerged deciduous molar which caused impaction of the second premolar and tipping of the first molar was presented. In addition, value of computed tomography (CT) for locating the vital anatomic structures was discussed. In our case, CT has been supplied effective information about localization of the vital structures and amount of bone volume during the diagnosis and treatment planning period in addition to the routine dental radiographies.

K?rz?oglu, Zuhal; Karay?lmaz, Huseyin; Baykal, Bahattin

2007-01-01

186

A new culture method assuring the three-dimensional development of the mouse embryonic molar tooth In vitro  

Microsoft Academic Search

Summary  Mandibular first molars from 17-day-old mouse embryos were cultivatedin vitro for 10 days using a new organ culture method. This method consisted of using a small glass dish and an agar chamber to slowly\\u000a float the molars to the gas-medium interface where they were maintained by the surface tension of the medium. The molars developed\\u000a three-dimensionally through the use of

Y. Sakakura

1986-01-01

187

Apparent molar volumes and compressibilities of tetrabutyl-ammonium bromide in organic solvents  

Microsoft Academic Search

The densities of tetra-n-butylammonium bromide in 1-propanol, 1-butanol, acetone at (288.15, 293.15, 298.15, 303.15, 308.15, 313.15, and 323.15)K and sound velocities at 298.15K have been measured. From these data apparent molar volumes V? at (288.15, 293.15, 298.15, 303.15, 308.15, 313.15, and 323.15)K and the apparent molar isenotropic compressibility KS,?, at T=298.15K of tetrabutylammonium bromide in nonaqueous solvents have been determined.

Joanna Krakowiak

2011-01-01

188

Upper molar distalization on palatal miniscrews: an easy to manage palatal appliance.  

PubMed

Upper molar distalization supported by miniscrews has become increasingly popular in the last years. A detailed clinical and lab procedure for the realization of a distalization appliance (fast back or distal jet) connected to miniscrews inserted in the anterior region of the palate is presented. A case report illustrates the use of a fast back appliance supported by miniscrews to correct the mesial shift of the molars and of the premolars as a consequence of an early loss of the maxillary deciduous canines. PMID:22583590

Huanca Ghislanzoni, Luis Tomas; Piepoli, Claudio

2012-05-01

189

Distalization of maxillary molars using a lever arm and mini-implant.  

PubMed

This article describes the orthodontic treatment of a young woman with a Class II malocclusion and maxillomandibular prognathism. One orthodontic mini- implant was placed in the posterior area of the palate to provide anchorage for?a transpalatal arch. The force for molar distalization was applied using an elastic chain from the lever arm inserted on the transpalatal arch to the mini-implant. Two sliding jigs were applied buccally as a complement for Class II malocclusion correction. This system created an efficient mechanotherapy for maxillary molar distalization. The active treatment period was 19 months. Normal overjet and reduction of maxillomandibular prognathism were obtained, and labial balance was improved. PMID:23646324

Gurgel, Júlio de Araújo; Pinzan-Vercelino, Célia Regina Maio; Bramante, Fausto Silva; Rivera, Alan Poy

2013-01-01

190

Contemporary endodontic management of four rooted maxillary second molar using waveOne  

PubMed Central

Knowledge of root canal morphology and variations is an essential factor to successful endodontic treatment. Presence of extra roots, canals, lateral canals, deltas etc., is commonly encountered. Maxillary second molar with two palatal roots or root canals is a rare dental anatomy. The purpose of this case report is to describe the successful endodontic management of a maxillary second molar with four root canals using a single reciprocating file system. The morphology is a typical characterized by two palatal roots with widely separated two orifices and canals. The tooth presented an individual mesiobuccal, distobuccal and two separate palatal roots.

Pawar, Ajinkya M; Kokate, Sharad R

2014-01-01

191

Modified lingual split technique for extraction of impacted mandibular third molars.  

PubMed

Critical evaluation of existing chisel and bur techniques for removal of impacted mandibular third molars reveals a high incidence of complications. Both approaches require creation of a buccal defect immediately distal to the second molar for the insertion of an elevator, which may cause pocketing to occur postoperatively. The method described here minimizes periosteal reflection, almost completely avoids loss of bone, and effectively reduces the use of rotary instrumentation. The planning of the soft tissue flaps and bony cuts assists in primary wound closure, obliteration of dead space, and reduction of postoperative morbidity. PMID:6930459

Lewis, J E

1980-08-01

192

Contemporary endodontic management of four rooted maxillary second molar using waveOne.  

PubMed

Knowledge of root canal morphology and variations is an essential factor to successful endodontic treatment. Presence of extra roots, canals, lateral canals, deltas etc., is commonly encountered. Maxillary second molar with two palatal roots or root canals is a rare dental anatomy. The purpose of this case report is to describe the successful endodontic management of a maxillary second molar with four root canals using a single reciprocating file system. The morphology is a typical characterized by two palatal roots with widely separated two orifices and canals. The tooth presented an individual mesiobuccal, distobuccal and two separate palatal roots. PMID:24808714

Pawar, Ajinkya M; Kokate, Sharad R

2014-01-01

193

Loss of molars early in life develops behavioral lateralization and impairs hippocampus-dependent recognition memory  

PubMed Central

Background Using senescence-accelerated mouse prone 8 (SAMP8), we examined whether reduced mastication from a young age affects hippocampal-dependent cognitive function. We anesthetized male SAMP8 mice at 8 weeks of age and extracted all maxillary molar teeth of half the animals. The other animals were treated similarly, except that molar teeth were not extracted. At 12 and 24 weeks of age, their general behavior and their ability to recognize novel objects were tested using the open-field test (OFT) and the object-recognition test (ORT), respectively. Results The body weight of molarless mice was reduced significantly compared to that of molar-intact mice after the extraction and did not recover to the weight of age-matched molar-intact mice throughout the experimental period. At 12 weeks of age, molarless mice showed significantly greater locomotor activity in the OFT than molar-intact mice. However, the ability of molarless mice to discriminate a novel object in the ORT was impaired compared to that of molar-intact mice. The ability of both molarless and molar-intact SAMP8 mice to recognize objects was impaired at 24 weeks of age. These results suggest that molarless SAMP8 mice develop a deficit of cognitive function earlier than molar-intact SAMP8 mice. Interestingly, both at 12 and 24 weeks of age, molarless mice showed a lateralized preference of object location in the encoding session of the ORT, in which two identical objects were presented. Their lateralized preference of object location was positively correlated with the rightward turning-direction preference, which reached statistical significance at 24 weeks of age. Conclusions Loss of masticatory function in early life causes malnutrition and chronic stress and impairs the ability to recognize novel objects. Hyperactivation and lateralized rotational behavior are commonly observed with dysfunction of the dopaminergic system, therefore, reduced masticatory function may deplete the mesolimbic and mesocorticolimbic dopaminergic systems to impair the cognitive functions of selective attention and recognition memory in the prefrontal cortex and the hippocampus.

2014-01-01

194

Preoperative Intravenous Tramadol Versus Diclofenac for Preventing Postoperative Pain After Third Molar Surgery: A Comparative Study  

Microsoft Academic Search

Purpose  The purpose of this study was to compare the analgesic efficacy of a single-dose of preoperative intravenous tramadol versus\\u000a diclofenac in preventing pain after third molar surgery.\\u000a \\u000a \\u000a \\u000a \\u000a Materials and Methods  Fifty patients undergoing elective third molar surgery were randomly assigned into one of the two groups (25 in each group):\\u000a Group 1 received diclofenac 75 mg, and Group 2 received tramadol 50 mg

Manish Kumar Pandit; Suhas Godhi; Amit B. Lall

195

Thermochemistry of amines: experimental standard molar enthalpies of formation of some aliphatic and aromatic amines  

Microsoft Academic Search

The standard (p°=0.1 MPa) molar enthalpies of formation ?fHm° (1 or cr) at the temperatureT=298.15 K were measured using combustion calorimetry forN,N-dimethyloctylamine (A), 2,4-dimethylaniline (B), 2,5-dimethylaniline (C),N-ethylaniline (D),N-benzylaniline (E), andN,N-dimethylaniline (F). The standard molar enthalpies of vaporization ?lgHm° or sublimation ?crgHm° of the compounds were obtained from the temperature variation of the vapour pressure measured in a flow system. In

Sergey P. Verevkin

1997-01-01

196

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

197

Pseudo-critical behavior on the partial molar volume of solutes in the isotropic phase of liquid crystal  

NASA Astrophysics Data System (ADS)

Temperature dependence of partial molar volume of 4-amino-4'-nitrobiphenyl (ANB) and 4,4'-dinitrobiphenyl (DNB) in the isotropic phase of 4- n-pentyl-4'-cyanobiphenyl (5CB) was determined. Addition of ANB to 5CB causes increase of isotropic-nematic phase transition temperature ( TIN) [1]. The decrease of partial molar volume of ANB was observed while the increase of partial molar volume of DNB and triphenyl phosphite (TPP) [8] was observed with approaching TIN. The anomalous behavior of partial molar volume was discussed using treatments similar to that of other thermodynamic derivatives in the I-N transition.

Matsuoka, Tatsuro; Nakamura, Shunsuke; Yamaguchi, Tsuyoshi; Koda, Shinobu

2012-01-01

198

[Stages of formation and calcification of the third molar (radiographic study of 500 Mexican children and adolescents)].  

PubMed

Five hundred orthopantomograph radiographs of mexican children and adolescent from 7 to 18 tears old were reviewed in order to establish the third molar formation and calcification stages and the most frequent anomalies related to these teeth. We find that tooth bud presence is between 9 and 11 years; Third molar is absent in 32.4% of the population; 7.4% of the molars presented early formation stage malposition; Therefore oligodontia diagnosis and third molar malposition can not be done before 13 years of age. PMID:2222754

Llarena del Rosario, M E; Nuno González, M M

1990-01-01

199

Brief communication: Dental development and enamel thickness in the Lakonis Neanderthal molar  

Microsoft Academic Search

Developmental and structural affinities between modern human and Neanderthal dental remains continue to be a subject of debate as well as their utility for informing assessments of life history and taxonomy. Excavation of the Middle Paleolithic cave site Lakonis in southern Greece has yielded a lower third molar (LKH 1). Here, we detail the crown development and enamel thickness of

T. M. Smith; K. Harvati; A. J. Olejniczak; D. J. Reid; J.-J. Hublin; E. Panagopoulou

2009-01-01

200

Prediction of postoperative facial swelling, pain and trismus following third molar surgery based on preoperative variables  

PubMed Central

Objective: This paper investigates the relationship between preoperative findings and short-term outcome in third molar surgery. Study design: A prospective study was carried out involving 80 patients who required 160 surgical extractions of impacted mandibular third molars between January 2009 and December 2010. All extractions were performed under local anesthesia by the same dental surgeon. Swelling and maximal inter-incisor distance were measured at 48 h and on the 7th day postoperatively. Mean visual analogue pain scores were determined at four different time periods. Results: One-hundred eight (67.5%) of the 160 extractions were performed on male subjects and 52 (32.5%) were performed on female subjects. Median age was 22.46 years. The amount of facial swelling varied depending on gender and operating time. Trismus varied depending on gender, operating time and tooth sectioning. The influence of age, gender and operating time varied depending on the pain evaluation period (p < 0.05). Conclusions: Short-term outcomes of third molar operations (swelling, trismus and pain) differ depending on the patients’ characteristics (age, gender and body mass index). Moreover, surgery characteristics such as operating time and tooth sectioning were also associated with postoperative variables. Key words:Third molar extraction, pain, swelling, trismus, postoperative findings, prediction.

de Souza-Santos, Jadson A.; Martins-Filho, Paulo R.; da Silva, Luiz C.; de Oliveira e Silva, Emanuel D.; Gomes, Ana C.

2013-01-01

201

Determination of the Molar Volume of Hydrogen from the Metal-Acid Reaction: An Experimental Alternative.  

ERIC Educational Resources Information Center

Describes an alternative technique for determining the molar volume of hydrogen from the metal-acid reaction in which the metal sample is encased in a specially prepared cage and a pipette filler is used to fill an inverted burette with water. Eliminates some difficulties encountered with the conventional technique. (JRH)

de Berg, Kevin; Chapman, Ken

1996-01-01

202

The Location and Accessibility of the Second Mesiobuccal Canal in Maxillary First Molar  

PubMed Central

Objectives: The purpose of this study was to examine the location and accessibility of the second mesibuccal canal in maxillary first molar of a Turkish sub-population. Methods: Presence and accessibility of the MB2 canal in 110 extracted maxillary first molars was examined with unaided vision, dental loups and the DOM. To characterize the geometrical location of MB2 canals, photographs of pulp chambers were obtained. Results: With the unaided vision, 58 MB2 canal orifices and after evaluation with the dental loup, DOM an additional 28 MB2 canal orifices were detected. In 65 molars, the MB2 canal orifices was located 0.87 mm distally and 1.73 mm palatally to the main mesiobuccal canal and in the remaining 21 molars was 0.72 mm mesially and 1.86 mm palatally. Conclusions: Presence of second mesiobuccal canal was similar to the other studies but in a Turkish sub-population it originates mainly distal to the main MB canal.

Tuncer, Aysun Kara; Haznedaroglu, Faruk; Sert, Semih

2010-01-01

203

Pulpotomy of human primary molars with MTA and Portland cement: a randomised controlled trial  

Microsoft Academic Search

Objective This study compared the clinical and radiographic effectiveness of mineral trioxide aggregate (MTA) and Portland cement (PC) as pulp dressing agents in carious primary teeth.Methodology Thirty carious primary mandibular molars of children aged 5-9 years old were randomly assigned to MTA or PC groups, and treated by a conventional pulpotomy technique. The teeth were restored with resin modified glass

A. B. S. Moretti; T. M. Oliveira; A. P. C. Fornetti; C. F. Santos; M. A. A. M. Machado; R. C. C. Abdo; V. T. Sakai

2009-01-01

204

Pulpotomías en molares primarios. Evaluación clínico radiográfica de formocresol o trióxido mineral agregado  

Microsoft Academic Search

Advances in Dentistry could not identify yet an ideal endodontic treatment showing high clinical success rates and allowing maintenance of deciduous molars until its normal exfoliation. Formocresol as a pulpo- tomy medicament has been, and continues being the most popular medication in spite of its local and sys- temic toxicity. The aim of this prospective study was to evaluate the

ANA M. BIONDI; SILVINA G. CORTESE; ANDREA ORTOLANI; CAROLINA BENCHUYA; MABEL TEDESCO

205

Summary of: Pulpotomy of human primary molars with MTA and Portland cement: a randomised controlled trial  

Microsoft Academic Search

Objective This study compared the clinical and radiographic effectiveness of mineral trioxide aggregate (MTA) and Portland cement (PC) as pulp dressing agents in carious primary teeth.Methodology Thirty carious primary mandibular molars of children aged 5-9 years old were randomly assigned to MTA or PC groups, and treated by a conventional pulpotomy technique. The teeth were restored with resin modified glass

M. Duggal

2009-01-01

206

A novel mutation in PAX9 causes familial form of molar oligodontia  

Microsoft Academic Search

PAX9 is a paired domain transcription factor that plays a critical role in odontogenesis. All mutations of PAX9 identified to date have been associated with nonsyndromic form of tooth agenesis. The present report describes an unusual novel mutation in PAX9 identified in a family with severe molar oligodontia. This heterozygous deletion combined with 24 bp insertion (including a 5? splice

Adrianna Mostowska; Barbara Biedziak; Wieslaw H Trzeciak

2006-01-01

207

Endodontic management of a mandibular second molar with radix entomolaris: a case report.  

PubMed

The presence of radix entomolaris (RE) in a mandibular first molar is a common occurrence in certain ethnic groups, but the presence of RE in a mandibular second molar is a rare occurrence. In the present case, RE was identified from preoperative radiographs and confirmed using cone-beam computed tomography (CBCT). The access cavity was modified to locate the RE. Cleaning and shaping were performed with nickel-titanium rotary instruments. Obturation was completed with gutta-percha cones using AH Plus (Dentsply Detrey GmbH) as sealer. From the CBCT axial images, the RE was determined to have a Type III curvature by the De Moor classification, Type B separate RE by the Carlsen and Alexandersen classification, and radiographically, a Type i image by the Wang classification. The presence of RE in the mandibular second molar makes it essential to anticipate and treat the distolingual root canal. This case report highlights the usefulness of CBCT for assessing RE in the mandibular second molar, which can help the clinician in making a confirmatory diagnosis and assessing the morphology of the root canal. PMID:24790927

Hannah, Rosaline; Kandaswamy, Deivanayagam; Jayaprakash, Nachimuthu

2014-05-01

208

Persistent deciduous molar as an etiology for a maxillary sinus mucocele.  

PubMed

Mucoceles are accumulations of trapped mucus, forming cystic expansile lesions. Maxillary sinus mucoceles are rare amongst paranasal sinus mucoceles, usually being a late sequel of Caldwell-Luc surgery. We present a case of a maxillary sinus mucocele due to a persistent carious deciduous molar in a middle aged patient, reported to highlight its unusual etiology. PMID:22754822

Tuli, Isha Preet; Pal, Indranil; Chakraborty, Suvamoy; Sengupta, Subhabrata

2011-07-01

209

Influence of the Broadening of Vibrational Bands on the Relative Order of Their Molar Extinction Coefficients  

Microsoft Academic Search

The broadening of transitions in the spectra of organic molecules in the liquid phase, under perturbations whose type may be the solvation effects, causes changes of the molar extinction coefficients ?. The problem has been known for a longtime and several attempts have been made to produce a measure of the width of complex absorption spectra and of their fine

B. Vidal; C. Dupret; A. Darry-Henaut

1986-01-01

210

Enamel microstructure and microstrain in the fracture of human and pig molar cusps  

Microsoft Academic Search

The role of microstructure in enamel strain and breakage was investigated in human molar cusps and those of the pig, Sus scrofa. Rosette strain gauges were affixed to cusp surfaces (buccal human M3, n=15, and lingual pig M1, n=13), and a compressive load was applied to individual cusps using an MTS materials testing machine. Load and strain data were recorded

T. E. Popowics; J. M. Rensberger; S. W. Herring

2004-01-01

211

Post-natal effect of overexpressed DKK1 on mandibular molar formation.  

PubMed

Dickkopf-related protein 1 (DKK1) is a potent inhibitor of Wnt/?-catenin signaling. Dkk1-null mutant embryos display severe defects in head induction. Conversely, targeted expression of Dkk1 in dental epithelial cells leads to the formation of dysfunctional enamel knots and subsequent tooth defects during embryonic development. However, its role in post-natal dentinogenesis is largely unknown. To address this issue, we studied the role of DKK1 in post-natal dentin development using 2.3-kb Col1a1-Dkk1 transgenic mice, with the following key findings: (1) The Dkk1 transgene was highly expressed in pulp and odontoblast cells during post-natal developmental stages; (2) the 1(st) molar displayed short roots, an enlarged pulp/root canal region, and a decrease in the dentin formation rate; (3) a small malformed second molar and an absent third molar; (4) an increase of immature odontoblasts, few mature odontoblasts, and sharply reduced dentinal tubules; and (5) a dramatic change in Osx and nestin expression. We propose that DKK1 controls post-natal mandibular molar dentin formation either directly or indirectly via the inhibition of Wnt signaling at the following aspects: (i) post-natal dentin formation, (ii) formation and/or maintenance of the dentin tubular system, (iii) mineralization of the dentin, and (iv) regulation of molecules such as Osx and nestin. PMID:21917600

Han, X L; Liu, M; Voisey, A; Ren, Y S; Kurimoto, P; Gao, T; Tefera, L; Dechow, P; Ke, H Z; Feng, J Q

2011-11-01

212

Influence of cryopreservation on the pulpal tissue of immature third molars in vitro.  

PubMed

The purpose of this study was to evaluate in vitro the viability of isolated and non-isolated pulpal tissue of immature third molars after cryopreservation. This study was divided in three different experiments. Experiment 1: Pulpal tissue isolated from 19 third molars was divided in horizontal segments. Each segment was cultured separately in order to evaluate whether differences in growth capacity within the tissue could be found. Experiment 2: Pulpal tissue isolated from 27 third molars was divided in a mesial and a distal part. One part was cryopreserved before culturing, the other part was cultured immediately. Growth capacity of cryopreserved and non-cryopreserved tissue was evaluated and compared. Experiment 3: 43 third molars were cryopreserved. After thawing, the dimension of the apical foramen was measured and the pulp was isolated and segmented horizontally. The different parts were cultured and growth capacity was evaluated and compared. Results of experiment 1 and 2 showed no significant difference in growth capacity between fibroblasts originating from different pulpal segments of the same tooth without cryopreservation and between fibroblasts originating from cryopreserved and non-cryopreserved isolated pulpal tissue. In experiment 3 it was demonstrated that the dimension of the apical foramen and pulpal viability after cryopreservation are positively correlated. A minimum dimension of 9.42 mm(2) enables the cryoprotective agent to penetrate sufficiently and to protect the pulpal tissue from apex to crown. This study proved that cryopreservation of human pulpal tissue is possible if the cryoprotective agent can reach the entire pulp. PMID:19685168

Temmerman, Liesbeth; Beele, Hilde; Dermaut, Luc R; Van Maele, Georges; De Pauw, Guy A M

2010-08-01

213

Post-natal Effect of Overexpressed DKK1 on Mandibular Molar Formation  

PubMed Central

Dickkopf-related protein 1 (DKK1) is a potent inhibitor of Wnt/?-catenin signaling. Dkk1-null mutant embryos display severe defects in head induction. Conversely, targeted expression of Dkk1 in dental epithelial cells leads to the formation of dysfunctional enamel knots and subsequent tooth defects during embryonic development. However, its role in post-natal dentinogenesis is largely unknown. To address this issue, we studied the role of DKK1 in post-natal dentin development using 2.3-kb Col1a1-Dkk1 transgenic mice, with the following key findings: (1) The Dkk1 transgene was highly expressed in pulp and odontoblast cells during post-natal developmental stages; (2) the 1st molar displayed short roots, an enlarged pulp/root canal region, and a decrease in the dentin formation rate; (3) a small malformed second molar and an absent third molar; (4) an increase of immature odontoblasts, few mature odontoblasts, and sharply reduced dentinal tubules; and (5) a dramatic change in Osx and nestin expression. We propose that DKK1 controls post-natal mandibular molar dentin formation either directly or indirectly via the inhibition of Wnt signaling at the following aspects: (i) post-natal dentin formation, (ii) formation and/or maintenance of the dentin tubular system, (iii) mineralization of the dentin, and (iv) regulation of molecules such as Osx and nestin.

Han, X.L.; Liu, M.; Voisey, A.; Ren, Y.S.; Kurimoto, P.; Gao, T.; Tefera, L.; Dechow, P.; Ke, H.Z.; Feng, J.Q.

2011-01-01

214

Occlusion regulates tooth-root elongation during root development in rat molars.  

PubMed

Occlusion is commenced by contact of a tooth with an opposing tooth and is the mechanical force working against the periodontal ligament (PDL). However, the influences of occlusion during root development remain uncertain. By extracting the unerupted counterpart molars of rats, we established a non-occlusal model that directly examined the effects of the absence of occlusion in developing molars using micro-computed tomography (?-CT) and histological procedures. The ?-CT data for experimental molars confirmed no attrition and hypogenesis of the alveolar bone. Root lengths in experimental groups increased more than in control groups. Histological findings of experimental molars showed a wide crown pulp, a long and narrow root, immature Sharpey's fibers, and hypogenesis of cementum. Proliferating cells localized in Hertwig's epithelial root sheath (HERS), the apical pulp, and the PDL of experimental teeth. Furthermore, cell-proliferative activity in experimental roots exceeded that in normal roots. These data indicate that cell proliferation is decreased by occlusion during root formation. Thus, occlusion is one factor that regulates root elongation. PMID:22112026

Nakasone, Naohiro; Yoshie, Hiromasa

2011-12-01

215

A familial case of recurrent hydatidiform molar pregnancies with biparental genomic contribution  

Microsoft Academic Search

Hydatidiform mole is a benign trophoblastic neoplasia characterized by an abnormal development of the embryo and proliferation of placental villi. Using microsatellite markers amplified by the polymerase chain reaction, we have performed a genetic study on eight independent molar tissues occurring in two sisters. Karyotype and genotype data demonstrate a diploid and biparental constitution in seven of the analyzed moles

Mazen N. Helwani; Muhieddine Seoud; Laila Zahed; Ghazi Zaatari; Ali Khalil; Rima Slim

1999-01-01

216

Placental isoferritin levels during first trimester of normal and complete molar gestations  

Microsoft Academic Search

Serum placental isoferritin levels (PLF) levels were measured in 33 patients admitted for routine scanning of a first trimester normal singleton pregnancy and six patients who were hospitalized for uterine evacuation of a complete molar gestation. Venous blood was obtained upon admission and before curettage, when necessary. Serum was separated into glass tubes, immediately frozen and stored at ?20°C until

R. Maymona; Z. Weinraub; I. Bukovsky; C. Moroz

1995-01-01

217

A morphometric analysis of maxillary molar crowns of Middle-Late Pleistocene hominins  

Microsoft Academic Search

This study explores the significance of shape differences in the maxillary first molar crowns of Neandertals and anatomically modern humans. It uses morphometric analysis to quantify these differences and to investigate how the orientation of major cusps, relative cusp base areas and occlusal polygon area influence crown shape. The aims of this study were to 1) quantify these data to

Shara E. Bailey

2004-01-01

218

Dental Caries Area of Rat Molar Expanded by Cigarette Smoke Exposure  

Microsoft Academic Search

Objectives: Passive smoking is the involuntary inhalation of cigarette smoke (CS) and has an adverse impact on oral health. We examined the effect of CS exposure on caries risk and experimental dental caries. Methods: Experimental dental caries was induced in rat maxillary molars which were inoculated orally with Streptococcus mutans MT8148 and maintained on a cariogenic diet (diet 2000) and

Y. Fujinami; K. Nakano; O. Ueda; T. Ara; T. Hattori; T. Kawakami; P.-L. Wang

2011-01-01

219

Maxillary molar distalization with MGBM-system in class II malocclusion  

PubMed Central

Aims: Objective of this retrospective study was to evaluate the treatment effects of the MGBM-System (G.B Maino, A. Giannelly, R. Bernard, P. Mura), a new intraoral device to treat Class II malocclusions Materials and Methods: A retrospective study was conducted to compare the pre-distalization and post-distalization cephalograms and dental model casts of 30 patients (15 male, 15 female) with Class II malocclusion treated with MGBM-System. Mean age at the beginning of treatment was 13.3 years (standard deviation 3.3). Angular, horizontal and vertical measurements were recorded to monitor skeletal and dental-alveolar changes. Molar movements in horizontal plane were monitored by making dental measurements on dental model casts. Results: The MGBM-System produced a rapid molar distalization and Class II relationship was corrected in 8 months ± 2.05, on average. The maxillary first molars were distalized of 4.14 (PTV-6 cemento-enamel junction), associated with a significant distal axis incline of 10. 5° referred to SN and a significant intrusion of 1.3 mm (PP). As for anchorage loss, the first premolar exhibited a significant mesial movement of 0.86 mm, associated with a significant mesial axis incline of 2.46°. No significative changes in either sagittal or vertical skeletal relationship were observed. Conclusion: The results suggest that the MGBM-System is an efficient and reliable device for distalizing the maxillary permanent first and second molars.

Maino, Giuliano; Mariani, Lisa; Bozzo, Ida; Maino, Giovanna; Caprioglio, Alberto

2013-01-01

220

Sensibility and taste alterations after impacted lower third molar extractions. A prospective cohort study  

PubMed Central

Objectives: To determine the incidence, severity and duration of lingual tactile and gustatory function impairments after lower third molar removal. Study Design: Prospective cohort study with intra-subject measures of 16 patients undergoing lower third molar extractions. Sensibility and gustatory functions were evaluated in each subject preoperatively, one week and one month after the extraction, using Semmes-Weinstein monofilaments and 5 different concentrations of NaCl, respectively. Additionally, all patients filled a questionnaire to assess subjective perceptions. Results: Although patients did not perceive any sensibility impairments, a statistically significant decrease was detected when Semmes-Weinstein monofilaments. This alteration was present at one week after the surgical procedure and fully recovered one month after the extraction. There were no variations regarding the gustatory function. Conclusions: Lower third molar removal under local anesthesia may cause light lingual sensibility impairment. Most of these alterations remain undetected to patients. These lingual nerve injuries are present one week after the extraction and recover one month after surgery. The taste seems to remain unaffected after these procedures. Key words:Lingual nerve, third molar, nerve injury, paresthesia, surgical extraction

Ridaura-Ruiz, Lourdes; Valmaseda-Castellon, Eduard; Berini-Aytes, Leonardo; Gay-Escoda, Cosme

2012-01-01

221

Perioperative Progress Check of Interdental Forces Following Extraction of the Third Molars  

Microsoft Academic Search

With the aim of checking the progress of mesially directed forces in a complete dental arch, we measured the interdental frictional forces in a population of 44 patients with erupting maxillary and mandibular third molars. The measurements were taken preoperatively and postoperatively 1, 2, 3, 7, and 12 weeks and also 1 year after extraction of surgical removal of the

Robert Fuhrmann; Christoph Grave; Peter Diedrich

2000-01-01

222

Endodontic management of a mandibular second molar with radix entomolaris: a case report  

PubMed Central

The presence of radix entomolaris (RE) in a mandibular first molar is a common occurrence in certain ethnic groups, but the presence of RE in a mandibular second molar is a rare occurrence. In the present case, RE was identified from preoperative radiographs and confirmed using cone-beam computed tomography (CBCT). The access cavity was modified to locate the RE. Cleaning and shaping were performed with nickel-titanium rotary instruments. Obturation was completed with gutta-percha cones using AH Plus (Dentsply Detrey GmbH) as sealer. From the CBCT axial images, the RE was determined to have a Type III curvature by the De Moor classification, Type B separate RE by the Carlsen and Alexandersen classification, and radiographically, a Type i image by the Wang classification. The presence of RE in the mandibular second molar makes it essential to anticipate and treat the distolingual root canal. This case report highlights the usefulness of CBCT for assessing RE in the mandibular second molar, which can help the clinician in making a confirmatory diagnosis and assessing the morphology of the root canal.

Kandaswamy, Deivanayagam; Jayaprakash, Nachimuthu

2014-01-01

223

Corrosion of a Zinc Rotating Disk in One Molar Hydrochloric Acid.  

National Technical Information Service (NTIS)

The corrosion of a zinc rotating disk in one molar hydrochloric acid has been studied using a potentiodynamic polarization method. Experimental rotating-disk data at a rotation speed of 1600 rpm are presented. The polarization curves are analyzed to deter...

A. Hauser

1984-01-01

224

Age-Specific Angulation of Unerupted Human Third Molar Teeth in a Cross-Sectional Sample.  

National Technical Information Service (NTIS)

For males aged 18 to 21, the angulation of unerupted third molars was unrelated to age. A counterbalancing loss of data resulting from tooth eruption and extraction accounted for this null finding. The value of age-specific angulation in determining wheth...

M. E. Cohen R. G. Walter J. J. Hyman P. K. Tombasco

1985-01-01

225

Root resective procedures vs implant therapy in the management of furcation-involved molars.  

PubMed

Therapeutic decision making and successful treatment of furcation- involved molars has been a challenge for many clinicians. Over recent decades, several techniques have been advocated in the treatment of furcated molar teeth, including nonsurgical periodontal therapy, regenerative therapy, and resective surgical procedures. Today, root resection is considered a relevant treatment modality in the management of furcation- involved multirooted molars. However, root resective procedures are very technique-sensitive and require a high level of periodontal, endodontic, and restorative expertise. Given the high documented success rates of implant treatment, the clinician is increasingly confronted with the dilemma of whether to treat a furcated molar by traditional root resective techniques or to extract the tooth and replace it with a dental implant. This article reviews the outcomes of root resective therapy for the management of furcation-involved multirooted teeth and discusses treatment alternatives including implant therapy. Treatment guidelines for root resective therapy, along with advantages and limitations, are presented to help the clinician in the decision-making process. PMID:24701615

Kasaj, Adrian

2014-06-01

226

Molar Tooth Sign in Joubert Syndrome: Clinical, Radiologic, and Pathologic Significance  

Microsoft Academic Search

Joubert syndrome is a rare autosomal-recessive condition characterized by early hyperpnea and apnea, developmental delay, and truncal ataxia. We previously described key ocular motor signs in Joubert syndrome and the molar tooth sign resulting from dysplasia of the isthmic segment of the brain stem, superior cerebellar peduncles, and vermis. In this study, we obtained clinical and developmental data in 61

Bernard L. Maria; Ronald G. Quisling; Louis C. Rosainz; Anthony T. Yachnis; Jill Gitten; Duane Dede; Eileen Fennell

1999-01-01

227

Endogenous epidermal growth factor regulates the timing and pattern of embryonic mouse molar tooth morphogenesis  

Microsoft Academic Search

The tooth organ provides a model for discrete patterns of morphogenesis over short periods of developmental time. Studies were designed to test the hypothesis that endogenous epidermal growth factor IEGF) functions to regulate multiple cusp molar tooth morphogenesis during embryonic mouse development. The relative levels of endogenous EGF and EGF receptor (EGFR) transcripts were determined in both enamel organ epithelia

CHING-CHUN HU; YASUNORI SAKAKURA; YASUYUKI SASANO; LILLIAN SHUM; PABLO BRINGAS; ZENA WERB; HAROLD C. SLAVKIN

1992-01-01

228

An ultrastructural study of dentinogenesis and amelogenesis in rat molar tooth germs cultured in vitro  

Microsoft Academic Search

Molar tooth germs from three-day-old rats were cultured successfully for fourteen days, permitting the study of the development in vitro of both extracellular matrix and cellular elements such as odontoblasts and ameloblasts. The ultrastructure of the cultured tooth germs was compared with the ultrastructure of tooth germs in vivo at a comparable developmental stage. Progenitor cells of odontoblasts and ameloblasts

I. Gorter de Vries; P. C. Ameloot; D. Coomans; E. Wisse

1986-01-01

229

Distribution and synthesis of type I and type III collagens in developing mouse molar tooth root  

Microsoft Academic Search

The distribution and synthesis of type I and type III collagens in the mouse molar tooth root have been investigated by correlating light and electron immunohistochemical data. Purified rabbit antibodies were raised against mouse type I and type III collagens and indirect immunoperoxidase procedures were used. In these conditions, predentin, pre-bone, and pre-acellular cementum were intensely immunostained for type I

M. B. Andujar; D. J. Hartmann; H. Emonard; H. Magloire

1988-01-01

230

Dentoskeletal effects induced by rapid molar distalization with the first class appliance  

Microsoft Academic Search

The purpose of this study was to evaluate the treatment effects of the first class appliance (FCA; Leone, Firenze, Italy), a new intraoral device for unilateral or bilateral rapid molar distalizaton. A retrospective study was conducted to compare the predistalization and postdistalization cephalograms of 17 patients (10 male, 7 female) with Class II malocclusions treated with the FCA. Mean age

Arturo Fortini; Massimo Lupoli; Fabio Giuntoli; Lorenzo Franchi

2004-01-01

231

The Antibacterial Effects of Ornidazole on Primary Molars with Infected Pulps  

Microsoft Academic Search

The purpose of this study was to investigate the antibacterial effects of a short-term topical application of ornidazole on anaerobic microorganisms. The antibacterial properties of such materials against organisms at infected primary root canals have not been well documented. Twenty infected primary molars in this study were treated using ornidazole (Biteral, Roche). The bacterial contents of the roots were collected

B. Kargül; T. Kadir

2001-01-01

232

Closing anterior open bites by intruding molars with titanium miniplate anchorage  

Microsoft Academic Search

The intent of this study was threefold: (1) to validate true intrusion of molars in adults, (2) to test the stability of miniplates as anchorage for intruding posterior teeth in the maxilla, and (3) to record the skeletal and dental changes of open-bite closure. Four adult patients who had anterior open-bite malocclusions were selected to undergo posterior intrusion with miniplate

Keith H. Sherwood; James G. Burch; William J. Thompson

2002-01-01

233

Incidence of impacted mandibular and maxillary third molars: a radiographic study in a Southeast Iran population  

PubMed Central

Objectives: The aim of this study is to evaluate the position of impacted third molars based on the classifications of Pell & Gregory and Winter in a sample of Iranian patients. Study design: In this retrospective study, up to 1020 orthopantomograms (OPG) of the patients who were referred to the radiology clinics from October 2007 to January 2011 were evaluated. Data including the age, gender, the angulation type, width and depth of impaction were evaluated by statistical tests. Results: Among 1020 patients, 380(27.3%) were male and 640(62.7%) were female with the sex ratio was 1:1.7. Of the 1020 OPGs, 585 cases showed at least one impacted third molar, with significant difference between males (205; 35.1%) and females (380; 64.9%) (P = 0.0311). Data analysis showed that impacted third molars were 1.9 times more likely to occur in the mandible than in the maxilla (P =0.000). The most common angulation of impaction in the mandible was mesioangular impaction (48.3%) and the most common angulation of impaction in the maxilla was the vertical (45.3%). Impaction in the level IIA was the most common in both maxilla and mandible. There was no significant diffe-rence between the right and left sides in both the maxilla and the mandible. Conclusion: The pattern of third molar impaction in the southeast region of Iran is characterized by a high prevalence of impaction, especially in the mandible. Female more than male have teeth impaction. The most common angulation was the mesioangular in the mandible, and the vertical angulation in the maxilla. The most common level of impaction was the A and there was no any significant difference between the right and left sides in both jaws. Key words:Third molar, impaction, incidence, Iran.

Tahmasbi-Arashlow, Mehrnaz; Fahimi-Hanzaei, Farnaz

2013-01-01

234

Pain Control Following Impacted Third Molar Surgery with Bupivacaine Irrigation of Tooth Socket: A Prospective Study  

PubMed Central

Background and aims The surgical removal of the lower third molars is a procedure generally followed by side effects such as postoperative pain. The aim of this study was to evaluate the efficacy of socket irrigation with an anesthetic solution in relieving pain following impacted third molar surgery. Materials and methods Thirty-four patients (17 males and 17 females), aged 18-24 years, with bilateral impacted lower third molars were selected. Both third molars were extracted in one surgical session. Tooth sockets in each patient were rinsed randomly either with 4 mL of 0.5% bupivacaine hydrochloride plain (without vasoconstrictor) anesthetic solu-tion or 4 mL of normal saline, used as control. The patients were instructed not to use analgesics as long as possible, and if not, they were instructed to use an analgesic, and record the time. Pain severity was assessed using a visual analogue pain scale (VAPS) at 1-, 6-, 12-, and 24-hour intervals post-operatively. Data were analyzed using Pearson’s chi-square test and P <0.05 was considered statistically significant. Results Post-operative pain difference between the two groups was statistically significant at 1-, 6-, 12- and 24-hour post-operative intervals (P <0.05). Post-operative pain increased in both groups to a maximum 12 hours after surgery with signif-icant improvements after that. Conclusion Based on the results, the irrigation of surgery site with bupivacaine after third molar surgery significantly reduces post-operative pain.

Khorshidi Khiavi, Reza; Pourallahverdi, Maghsood; Pourallahverdi, Ayda; Ghorani Khiavi, Saadat; Ghertasi Oskouei, Sina; Mokhtari, Hadi

2010-01-01

235

Cone-Beam Computed Tomography Evaluation of Maxillary First and Second Molars in Iranian Population: A Morphological Study  

PubMed Central

Introduction: The aim of this in vitro study was to identify the root and canal morphology of maxillary first and second molars in Iranian population by taking and analyzing cone-beam computed tomography (CBCT) scans. Methods and Materials: Extracted maxillary first (n=125) and second (n=125) molars were collected from native Iranians and scanned by using a CBCT scanner. The number of roots and configuration of root canal system were classified according to Vertucci’s classification. Results: Two (1.6%) maxillary first and two (1.6%) maxillary second molars had four roots. Prevalence of root fusion was 2.4% and 8.8% in maxillary first and second molars, respectively. The most common canal morphology in the mesiobuccal roots of three-rooted first and second molars was type I (46.4% and 80.8%, respectively), followed by type VI (17.6%) in first molars. The predominant morphology of distobuccal and palatal roots in first and second molars was type I. Additional canal types were also identified. Conclusion: Profound knowledge of anatomic variations is necessary prior to cleaning and obturation of the root canal system. The most common discovered root morphology was three separate roots in both tooth types. The greatest variation in canal anatomy was discovered in the MB canals of both the first and second molars.

Rouhani, Armita; Bagherpour, Ali; Akbari, Majid; Azizi, Majid; Nejat, Amirhosein; Naghavi, Neda

2014-01-01

236

Excess molar volumes and viscosities of binary mixtures of diethylene glycol diethyl ether with chloroalkanes at 298.15 K  

Microsoft Academic Search

Excess molar volumes (VmE) and dynamic viscosities (?) at 298.15 K and atmospheric pressure for mixtures of diethylene glycol diethyl ether + dichloromethane, + trichloromethane, and + tetrachloromethane were determined as a function of composition. The excess molar volumes are all negative over the whole composition range. The deviations in viscosity (?ln?) and excess energies of activation (?G?E) for viscous

Amalendu Pal; Rakesh Kumar Bhardwaj

2003-01-01

237

The use of methylprednisolone versus diclofenac in the treatment of inflammation and trismus after surgical removal of lower third molars  

Microsoft Academic Search

Objective: To compare the efficacy of methylprednisolone (corticoid)versus diclofenac (nonsteroidal anti-inflammatory -NSAID-) in the treatment of inflammation and trismus after the surgical removal of lower third molars. Study design: Prospective study on 73 patients for the surgical removal of their lower third molars. These patients were separated in two groups at ramdom: the diclofenac group and the methylprednisolone group. A

Carmen López Carriches; José M; Martínez González; Manuel Donado Rodríguez

238

Piezoelectric bone surgery in the treatment of an osteoma associated with an impacted inferior third molar: a case report.  

PubMed

Operative removal of impacted mandibular third molars is a common and not riskless surgical procedure. We present an emblematic case of an osteoma closely associated with an impacted third left mandibular molar treated by Mectron Piezosurgery medical ultrasonic device. PMID:25002883

D'Amato, Salvatore; Sgaramella, Nicola; Vanore, Laura; Piombino, Pasquale; Orabona, Giovanni Dell'Aversana; Santagata, Mario

2014-01-01

239

Excess molar volumes, excess viscosities and refractive indices of a quaternary liquid mixture at 298.15 K  

Microsoft Academic Search

Density, viscosity and refractive index values for the propan-2-ol + methylacetate + dichloromethane + n-pentane mixture have been measured at 298.15 K, over the whole concentration range. Excess molar volumes and viscosities have been calculated. Flory's statistical theory has been applied to predict the excess molar volumes and compare then to the experimental data. We have also applied Grunberg and

Ernesto Caner; Graciela C. Pedrosa; Miguel Katz

1996-01-01

240

A case report of maxillary second molar with two palatal root canals and a furcal enamel pearl.  

PubMed

This case report presents an uncommon case of maxillary molar with two palatal root canals and an enamel pearl in the furcation area. The article discusses root canal complexities of maxillary second molars as well as possibility of coexisting anomalies in the region that makes radiographic interpretation difficult and compromises the success of endodontic treatment. PMID:23411467

Shojaeian, Shiva; Ghoddusi, Jamileh; Hajian, Sara

2013-01-01

241

Loss of molar occlusion and mandibular morphology in adults in an ancient human population consuming a coarse diet.  

PubMed

The purpose of the study is to investigate the link between number of molar teeth retained in occlusion and mandibular morphology in adults in an ancient, high dental wear human population. The study material comprises skeletons from Mediaeval Wharram Percy, England (N = 50 female, 69 male adults). It was hypothesized that adults retaining fewer occluding molars would show reduction in mandibular dimensions, particularly in the ascending ramus and gonial regions where the main muscles of mastication have their insertions. Molar occlusal status is assessed using the concept of functional units. Mandibular morphology is assessed using a suite of ten linear measurements plus the mandibular angle. Results show no evidence for any association between number of molars retained in occlusion and mandibular angle. There was an association between mandibular size and number of molars retained in occlusion, with smaller mandibular dimensions in those retaining fewer occluding molars. Some measurements were affected more than others so that there was also some shape alteration. Alteration of mandibular dimensions was more clearly demonstrable in females than in males. Only in females could significant reduction in the ascending ramus and gonial regions be demonstrated. Reasons for the apparent difference in response to loss of molar occlusion between male and female mandibles are unclear, but sex differences in bony metabolism mediated by hormonal factors may be implicated. Results suggest that care should be exercised when including mandibles from individuals showing loss of molar occlusion in morphological studies. PMID:24104725

Mays, Simon A

2013-11-01

242

Determination Of Partial Molar Volumes Of Iron Species In Silicate Melts  

NASA Astrophysics Data System (ADS)

One of the major questions of planetary geology is the composition and conditions of the Earth interior. Magmas are among our most important windows into the interior. Iron, being a major element with multiple valence states, is an important influence on redox state. One way to investigate redox state is via a volume equation of state. Density data are used in computing partial molar volumes, which may then be used to construct a volume equation of state. We have devised an apparatus which permits high-quality density measurements in silicate melts at high temperatures (up to ?1500 °C) and reduced oxygen fugacity at atmospheric pressure using the Archimedean single-bob method. With this apparatus, we have collected the first high-quality density data of iron-bearing silicate melts which had their iron predominately as ferrous. We measured the density of Columbia River Basalt (approximate temperature range: 1250 °C -- 1450 °C) and an artificial composition in the FeO-FeO1.5-CaO-SiO2 system (?1460 °C) at the oxygen fugacity corresponding to the Iron-Wüstite buffer. We used these data in conjunction with literature density data gathered at thermodynamic equilibrium to calculate the partial molar volume of the iron species as a function of temperature at standard pressure. We speciated iron according to: 0.4 FeO + 0.6 FeO1.5 ? FeO1.3 The partial molar volumes of FeO, FeO1.5, and FeO1.3 were fit well with no compositional dependence, despite the wide range of compositions included in this study. To the extent that melt structure can be inferred from partial molar volumes, this result suggests that there is no compositional dependency to the structure of any of these iron species. Our partial molar volumes of FeO and FeO1.5 are consistent within one standard error of those found by Lange & Carmichael (1987) and Ghiorso & Kress (2004). However, our partial molar volume for FeO1.3 at reference temperature was one-third that of Ghiorso & Kress (2004) (Lange & Carmichael (1987) did not include this species in their fit), which would result in greater conversion of FeO and FeO1.5 into FeO1.3 at pressure.

Dwyer, C. A.; Kress, V. C.

2009-12-01

243

Selenium/mercury molar ratios in freshwater, marine, and commercial fish from the USA: variation, risk, and health management.  

PubMed

Fish provide healthy protein as well as recreational and cultural benefits, but can also contain mercury (Hg), polychlorinated biphenyls (PCBs), and other contaminants that have adverse effects on humans and other organisms, particularly developing fetuses. Recently, some authors have suggested that a molar excess of selenium (Se) [e.g., selenium/mercury (Se/Hg) molar ratio >1] confers protection from Hg toxicity derived from fish consumption. Herein, we review our studies of Hg and Se in freshwater, marine, and commercial fish (mainly marine), examining the following: (1) whether and how Se/Hg molar ratios vary among species; (2) whether and how the molar ratios vary within species; (3) whether the molar ratios differ between freshwater and saltwater fish; (4) whether mean molar ratio values provide a reliable indication of potential risk to fish consumers; and (5) whether mean Se/Hg molar ratios are sufficiently constant (e.g., low variation) to allow for use in risk assessment, risk management, or risk communication. In saltwater fish, mean Se/Hg molar ratios varied from 0.3 in mako shark to 68.1 in whiting. For freshwater fish, the mean ratios varied from 0.68 in bowfin to 20.8 in black crappie. Commercial seafood (mainly saltwater) showed great variation in ratios; shrimp and scallops had very high ratios. There was somewhat less variability in the ratios for freshwater fish compared with the fish from saltwater, but there was no overall predictable difference in variation in Se/Hg molar ratios. For both saltwater and freshwater fish, some species with mean molar ratios above 1 had a significant proportion of individual fish with molar ratios below 1. Overall, this indicates great variation in measures of central tendencies and in measures of dispersion. We suggest that relying on the Se/Hg molar ratio as a method of predicting reduced risk from Hg toxicity is problematic because of the great variation among and within fish species, and the variation is not predictable because Hg varies by season, size of the fish, and location of the fish (which is not available for commercial fish). With the high variation in ratios, and low predictability, the ratios are currently not useful for risk assessment and risk management, and vulnerable individuals cannot rely on mean Se/Hg molar ratios for protection from Hg toxicity. PMID:24192499

Burger, Joanna; Gochfeld, Michael

2013-01-01

244

Endodontic Retreatment of a Mandibular Second Molar with four Separate Roots: A Case Report  

PubMed Central

Aberrations in the root canal anatomy are a commonly occurring phenomenon. Although the mandibular second molar is commonly a bi-rooted tooth with an uncomplicated endodontic anatomy, variations have to be considered every time endodontic therapy is performed. This case report describes the non-surgical endodontic retreatment performed on a mandibular second molar with four seperate roots and canals. ProTaper Universal rotary nickel-titanium instruments (Dentsply Maillefer, Ballaigues, Switzerland) for treatment and retreatment were used to remove the old gutta percha and to clean and shape all root canals, followed by the complete obturation of root canal system. Post-operative CBCT scan was taken to confirm the quality of the performed treatment.

Idris, Mohamed; Sakkir, Nasil; KJ, Nandakishore; Kini, Annapurna

2014-01-01

245

Changes in molar volume and heat capacity of actin upon polymerization.  

PubMed Central

We have used densimetry and microcalorimetry to measure the changes in molar volume and heat capacity of the actin molecule during Mg(2+)-induced polymerization. Molar volume is decreased by 720 ml/mol. This result is in contradiction with previous measurements by Ikkai and Ooi [(1966) Science 152, 1756-1757], and by Swezey and Somero [(1985) Biochemistry 24, 852-860]: both of these groups reported increases in actin volume during polymerization, of 391 ml/mol and 63 ml/mol respectively. We also observed a decrease in heat capacity of about 69.5 kJ.K-1.mol-1 during polymerization. This is in agreement with the concept of conformational fluctuation of proteins proposed by Lumry and Gregory [(1989) J.Mol. Liq. 42, 113-144]whereby either ligand binding by a protein or monomer-monomer interaction decreases the protein's conformational flexibility.

Quirion, F; Gicquaud, C

1993-01-01

246

Cuspal deflection in molars in relation to endodontic and restorative procedures.  

PubMed

The extent of cuspal flexure following endodontic and restorative procedures has important consequences for potential fracture. This study was undertaken to determine the extent to which cusps of molars are weakened by progressively larger restorative preparations and endodontic access. Cuspal flexure of 13 extracted, intact human mandibular molars was measured under controlled occlusal loading. A ramped load of 100 N was applied to the mesial cusps via a steel sphere, using a closed-loop servohydraulic testing machine. Lateral cuspal displacement was recorded by linear measuring devices (direct current differential transformers) accurate to 1 micron. Increasingly extensive MO or MOD cavity preparations followed by endodontic access were cut in each tooth. Cuspal deflection increased with increasing cavity size and was greatest following endodontic access. Cuspal deflections of more than 10 microns were observed. These findings reinforce the importance of cuspal coverage to minimize the danger of marginal leakage and cuspal fracture in endodontically treated teeth. PMID:7714437

Panitvisai, P; Messer, H H

1995-02-01

247

Determination of the passive absorption through the rat intestine using chromatographic indices and molar volume.  

PubMed

Immobilized artificial membrane (IAM) chromatography coupled to physicochemical descriptors was evaluated to model the passive intestinal absorption of drugs through rat gut sacs. The chromatographic capacity factors (logk'(IAM)) of 12 structurally diverse compounds were determined on a IAM PC DD2 column. The passive permeabilities (P(a)) of the drugs were determined through rat everted gut sacs or through non-everted sacs for actively transported molecules. Correlation studies between logk'(IAM), physicochemical descriptors and P(a) were conducted by stepwise multiple linear regression (MLR) and back-propagation neural network (BPNN). MLR and BPNN showed that logk'(IAM) was the descriptor which correlated best with P(a). Considering the molar volume as an additional descriptor, the correlation was improved. Retention indices on IAM and the molar volume can be used concurrently to predict passive drug absorption. PMID:11113641

Genty, M; González, G; Clere, C; Desangle-Gouty, V; Legendre, J Y

2001-01-01

248

Estimation of molar heat capacities in solution from gas chromatographic data.  

PubMed

The temperature dependence of retention data (retention or capacity factors) is measured for 35 aliphatic ketones and aldehydes as model compounds on a dimethylpolysiloxane stationary phase. A novel model is derived to determine the heat of solution and the solution molar heat capacities from the fits of the log natural of the difference of the retention factor and the column temperature (T) versus 1/T and the temperature arrangement. The convex curvature present in the residual plots of a former defined equation of ours disappears when applying a newly defined model. A detailed statistical analysis clearly shows the superiority of the refined model to the earlier one in a broader temperature range. The validation of this model is made through a comparison of heat capacity values taken from literature determined by different methods. The molar heat capacity of a pure liquid oxo compound is similar to that of when the same compound is solvated in a stationary phase. PMID:11277252

Héberger, K; Görgényi, M

2001-03-01

249

Endodontic treatment of a hypertaurodont mandibular second molar: a case report.  

PubMed

A 28-year old patient was referred for endodontic treatment of his left mandibular second molar. The patient had no history of systemic diseases and his chief complaint was spontaneous pain in left posterior region of mandible. Clinically, there was a deep caries in the left mandibular second molar. Radiographic examination of this tooth revealed a long crown containing large pulp chamber and two short roots with a apically located furcation, indicating hypertaurodontism. After coronal access preparation, five orifices were found including mesiolingual, mesiobuccal, distobuccal, mid-distal and distolingual. Subsequent to root canal preparation, a modified filling technique was used for canal obturation. After one year the treated tooth was symptom free. PMID:23130066

Janani, Maryam; Rahimi, Saeed; Shahi, Shahriar; Aghbali, Amirala; Zand, Vahid

2011-01-01

250

Prevalence of Taurodontism in Premolars and Molars in the South of Iran  

PubMed Central

Background and aims The study was undertaken to assess the prevalence of taurodontism and related systemic condi-tions and gender differences in premolars and molars of patients attending Shiraz Faculty of Dentistry. Materials and methods In this cross-sectional study, panoramic radiographs of 510 randomly selected patients were evaluated by a maxillofacial radiologist for the apically displaced pulp chamber. Detailed medical and family history of the patients was obtained. Results The prevalence of taurodontism in 510 panoramic views was 5.5% of patients. Females had significantly higher prevalence of taurodontism than men (P>0.05) and mandibular second molar was the most affected tooth. Conclusion Taurodontism was relatively common in population under study. A family history of other anomalies should be checked for affected patients.

Bronoosh, Pegah; Haghnegahdar, Abdolaziz; Dehbozorgi, Mehrnoosh

2012-01-01

251

Unusual treatment of bimaxillary dentoalveolar protrusion via miniscrews and molar extraction  

PubMed Central

This case report describes the treatment of a Saudi female patient, aged 13 years 8 months at the start of treatment, with a Class I bimaxillary dentoalveolar protrusion and extracted maxillary first molars. Miniscrews were placed bilaterally in the interdental space between both the upper and the lower posterior teeth. The treatment plan consisted of extraction of both lower first permanent molars, distalization of upper and lower premolars using miniscrews followed by en masse retraction of the upper and lower six anterior teeth. The active treatment period was 2 years 8 months. Arch retention was done using upper wrap-around retainer and lower fixed 3-3 retainer. The use of miniscrews helped to resolve the bimaxillary protrusion regardless of extraction pattern used.

Al-Fraidi, Ahmad; Afify, Ahmed R.

2012-01-01

252

Endodontic Retreatment of a Mandibular Second Molar with four Separate Roots: A Case Report.  

PubMed

Aberrations in the root canal anatomy are a commonly occurring phenomenon. Although the mandibular second molar is commonly a bi-rooted tooth with an uncomplicated endodontic anatomy, variations have to be considered every time endodontic therapy is performed. This case report describes the non-surgical endodontic retreatment performed on a mandibular second molar with four seperate roots and canals. ProTaper Universal rotary nickel-titanium instruments (Dentsply Maillefer, Ballaigues, Switzerland) for treatment and retreatment were used to remove the old gutta percha and to clean and shape all root canals, followed by the complete obturation of root canal system. Post-operative CBCT scan was taken to confirm the quality of the performed treatment. PMID:24783160

Idris, Mohamed; Sakkir, Nasil; Kj, Nandakishore; Kini, Annapurna

2014-03-01

253

Third molar surgical procedures: practices by maxillofacial and oral surgeons in South Africa.  

PubMed

An audit of the treatment procedures routinely adopted by maxillofacial and oral surgeons for the removal of impacted third molars under general anaesthesia was undertaken in South Africa. Most maxillofacial and oral surgeons agree on the method of bone removal, the prescribing of antibiotics, analgesic agents and mouthwashes, the suturing of the incision wound and the post-operative review of patients. The results were compared to a similar study undertaken by Falcon and Roberts (1992) in the UK. With the exception of the method of bone removal, maxillofacial and oral surgeons in both groups share a similar approach to the treatment procedures adopted in the removal of impacted third molars. Some variability, however, existed in both studies with regard to the use of intra-operative local anaesthetic agents, the administration of peri-operative steroids and the use of non-steroidal anti-inflammatory agents. PMID:9461974

Naidoo, L C

1996-06-01

254

Tree fine root Ca\\/Al molar ratio – Indicator of Al and acidity stress  

Microsoft Academic Search

High soil acidity and elevated soil Al concentrations limit plant growth in many terrestrial ecosystems. Aluminium toxicity can be ameliorated by Ca. Thus, Ca\\/Al molar ratios in soil solution and in plant tissues have been proposed as superior indicators than Al concentration itself for evaluating the Al toxicity stress to trees (Cronan & Grigal, J Environ Qual 1995;24:209 – 226). This article

E. I. Vanguelova; Y. Hirano; T. D. Eldhuset; L. Sas-Paszt; M. R. Bakker; Ü. Püttsepp; I. Brunner; K. Lõhmus; D. Godbold

2007-01-01

255

Molar volumes of molten indium at high pressures measured in a diamond anvil cell  

Microsoft Academic Search

Molar volumes of molten indium have been measured in an isothermal compression up to 8.5 GPa at 710(3) K in an externally heated diamond anvil cell. The measurement is based on the x-ray diffraction and x-ray absorption of materials using a synchrotron monochromatic x-ray microbeam. The fit to the results with the Birch-Murnaghan equation of state gives parameters of V0=16.80

Guoyin Shen; Nagayoshi Sata; Mathew Newville; Mark L. Rivers; Stephen R. Sutton

2002-01-01

256

Molar Pregnancy with False Negative ?-hCG Urine in the Emergency Department  

PubMed Central

This case describes an atypical presentation of molar pregnancy in an emergency department patient with abdominal pain and vaginal bleeding. The patient demonstrated clinical features of hydatidiform mole, including acute discharge of a large, grape-like vesicular mass, despite multiple negative urine pregnancy tests. These false-negative qualitative human chorionic gonadotropin assays were likely caused by the “high-dose hook effect” and may have delayed proper care of the patient, who displayed pulmonary choriocarcinoma at the time of diagnosis.

Hunter, Christopher L.; Ladde, Jay

2011-01-01

257

Endodontic management of a four rooted retained primary maxillary second molar  

PubMed Central

The presence of accessory roots is rare in the primary dentition. Complete knowledge and understanding of tooth anatomy is essential to carry out high quality dental treatment with excellent outcome. In addition, the persistent primary tooth and its missing permanent successor in the dental arch pose several hurdles in front of the clinician due to doubtful survival of primary tooth. In this paper, highlights the root canal treatment of a rarest four rooted retained primary maxillary second molar.

Chhabra, Naveen

2013-01-01

258

Toxicity of an effective amphotericin B formulation at high cationic lipid to drug molar ratio  

Microsoft Academic Search

Therapeutic activity of an effective and less nephrotoxic amphotericin B (AMB) formulation with dioctadecyldimethylammonium bromide (DODAB) bilayer fragments (named DODAB\\/AMB) inspired this toxicity survey in mice. At low drug to lipid molar ratios, hepatotoxicity, spleen damage and blood changes in comparison to DOC\\/AMB (sodium desoxycholate\\/amphotericin B, Fungizone) are evaluated ultimately showing toxic effects associated to DODAB only. Swiss Webster female

Nilton Lincopan; Primavera Borelli; Ricardo Fock; Elsa M. Mamizuka; Ana M. Carmona-Ribeiro

2006-01-01

259

Subconjunctival ecchymosis after extraction of maxillary molar teeth: a case report.  

PubMed

Extraction of teeth is usually performed by either intra-alveolar or trans alveolar methods. Subconjunctival ecchymosis occurring after intra-alveolar extraction of maxillary first and second molar teeth is a rare entity and finds no mention in the latest clinical literature. The etiology of subconjunctival ecchymosis includes traumatic and non-traumatic causes. We report a case and discuss the possible etiology and management of this complication. PMID:20406279

Kumar, Raichoor Anil; Moturi, Kishore

2010-06-01

260

Mineral trioxide aggregate a reliable alternative material for pulpotomy in primary molar teeth  

Microsoft Academic Search

DesignThis was a randomised controlled trial.InterventionThe trial assessed application of formocresol (FC) or mineral trioxide aggregate (MTA) during pulpotomy in primary molar teeth.Outcome measureTreatment was evaluated by recording clinical signs (spontaneous pain, swelling, pain on palpation or percussion and sinus tract formation) or radiological signs of failure (root resorption, periodontal ligament widening, and apical, lateral or furcal radiolucency).ResultsNo signs of

Chris Deery

2007-01-01

261

Incidence of deep fascial space infection after surgical removal of the mandibular third molars  

Microsoft Academic Search

Nine hundred and ninety-three patients who underwent surgical removal of the mandibular third molars with oral antibiotic\\u000a prophylaxis were examined to determine the incidence of postoperative deep fascial space infection and its background factors.\\u000a Postoperative deep fascial space infection was observed in 8 of the patients (0.8%; 4 males and 4 females), and submandibular\\u000a spaces were involved in all infected

Takashi Yoshii; Yoshihiko Hamamoto; Shigetada Muraoka; Atsushi Kohjitani; Osamu Teranobu; Shungo Furudoi; Takahide Komori

2001-01-01

262

Unilateral gingival fibromatosis with localized aggressive periodontitis (involving first molars): An unusual case report  

PubMed Central

An atypical and rare case report is presented here of a 16 years old female patient who presented with severe, unilateral, gingival enlargement along with aggressive periodontitis around first molars that was confined to the left side of her mouth. A careful recording of the case history and results of clinical examination, laboratory blood analysis, radiological findings, and microbiological and histopathological investigations were noted and a critical review of similar conditions was taken into account to arrive at the said diagnosis.

Sandhu, Sharn Pal; Kakar, Vipin; Gogia, Guneet; Narula, S. C.

2009-01-01

263

The mandibular third molar position as a predictive criteria for risk for pericoronitis: a retrospective study.  

PubMed

During the 6-month period from mid February 1988 to mid August 1988, 148 patients presented with 154 diagnosed cases of mandibular third molar pericoronitis. All patients were members of the recruit population stationed at the Recruit Training Command, Great Lakes, Illinois. Selected clinical parameters relating to the orientation and eruption status of these third molars were collected and analyzed. The goal was to obtain a predictive clinical profile of the impacted mandibular third molar (MTM) at greatest risk for pericoronitis in the young naval and Marine Corps personnel. The majority of pericoronitis cases, 120 of 148 or 81.0%, involved vertically oriented MTMs; of this total, 79.1% were erupted to the approximate height of the occlusal plane of the arch. The remaining 20.9% were at or below the height of contour of the adjacent tooth. Mesioangular impacted MTMs accounted for only 11.2% of pericoronitis cases. The remaining cases comprised distoangular and horizontally impacted MTMs (3.4% and 3.8%, respectively). Involvement by impinging maxillary dentition was observed in 39.7% of the vertically oriented MTMs, 56.2% of the mesioangular oriented MTMs, 40.0% of the distoangular MTMs, and 14.0% of the horizontally impacted MTMs. The mean value for occlusal coverage by a soft tissue operculum observed for all MTMs in this study was 49%. In the population studied, risk for pericoronitis appears to increase with greater vertical orientation and height of eruption. The absence of impinging maxillary dentition did not eliminate the risk of mandibular third molar pericoronitis. These data have implications for targeting treatment needs of naval and Marine Corps personnel who may be without dental support for extended periods of time. PMID:1603407

Halverson, B A; Anderson, W H

1992-03-01

264

The molar extinction coefficient of bacteriochlorophyll e and the pigment stoichiometry in Chlorobium phaeobacteroides  

Microsoft Academic Search

We have determined the molar extinction coefficient of bacteriochlorophyll (BChl) e, the main light-harvesting pigment from brown-coloured photosynthetic sulfur bacteria. The extinction coefficient was determined using pure [Pr,E]BChl eF isolated by reversed-phase HPLC from crude pigment extracts of Chlorobium (Chl.) phaeobacteroides strain CL1401. The extinction coefficients at the Soret and Qy bands were determined in four organic solvents. The extinction

Carles M. Borrego; Juan B. Arellano; Carles A. Abella; Tomas Gillbro; Jesús Garcia-Gil

1999-01-01

265

Determination of the molar extinction coefficient for the ferric reducing\\/antioxidant power assay  

Microsoft Academic Search

The FRAP reagent contains 2,4,6-tris(2-pyridyl)-s-triazine, which forms a blue–violet complex ion in the presence of ferrous ions. Although the FRAP (ferric reducing\\/antioxidant power) assay is popular and has been in use for many years, the correct molar extinction coefficient of this complex ion under FRAP assay conditions has never been published, casting doubt on the validity of previous calibrations. A

William A. Hayes; Daniel S. Mills; Rachel F. Neville; Jenna Kiddie; Lisa M. Collins

2011-01-01

266

Molar extinction coefficients of IR absorption bands of Cu(II) dipivaloylmethanate  

Microsoft Academic Search

IR absorption spectra of an intracomplex chelate compound of Cu(II) bis-dipivaloylmethanate in the spectral range 4000–300\\u000a cm?1 are investigated. A comparison is made between the spectra of the complex in different aggregative states: as a solution\\u000a in heptane and as condensed films. The molar extinction coefficients of absorption bands are calculated. The extinction coefficients\\u000a found are used to evaluate the

L. F. Bakhturova; V. V. Bakovets; T. M. Levashova; I. P. Dolgovesova; V. O. Borisov

2000-01-01

267

Glass ionomer-silver cermet Class II tunnel-restorations for primary molars.  

PubMed

Tunnel preparations preserve the anatomical marginal ridge and minimize the loss of healthy tooth structure adjacent to the carious lesion. When the practitioner has developed proficiency in restoring class II carious lesions with tunnel restorations, less treatment time is required than with traditional class II preparations. The technique for restoring a primary first molar with a class II carious lesion, using a tunnel preparation and Ketac-Silver restorative material is described. PMID:2968382

Croll, T P

1988-01-01

268

Single-rooted maxillary first molar with a single canal: endodontic retreatment.  

PubMed

This case report presents an unusual root canal system in a maxillary first molar tooth: a single canal in a single root. The endodontic access cavity displayed only 1 canal orifice. This case demonstrated that: 1) clinicians must have adequate knowledge about root canal morphology and its variations; 2) the location and morphology of root canals should be identified radiologically before the root canal treatment; and 3) careful examination of radiographs and the internal anatomy of teeth is essential. PMID:18926738

de la Torre, Francisco; Cisneros-Cabello, Rafael; Aranguren, José Luis; Estévez, Roberto; Velasco-Ortega, Eugenio; Segura-Egea, Juan José

2008-12-01

269

[Prediction and estimation on molar response values of alkane using molecular subgraph].  

PubMed

A new method based on topographical subgraph of alkanes is proposed and used for molar response values of alkanes. A novel coding, which derived from the numbers of molecular subgraph, is used to characterize molecular structure of alkanes. It showed that there is a very good correlation between the coding and molar response values. The results of multiple linear regression are as follows. Molar response values (SM) on FID: SM = 89.579 - 56.579x1 - 40.579x2 - 18.191x 3 - 2.677x4 + 11.818x5 + 25.690x6 + 40.421x7 + 54.421x8 + 13.926x9 + 15.524x10 + 13.923x11 + 13.857x12 + 30.079x13 + 30.403x14 + 32.677x15 + 29.030x16, N = 50, r = 0.9983, S = 1.9342; Molar response values (SM) on TCD: SM = 139.799 - 62.251x2 - 49.214x3 - 31.244x4 - 15.992x5 + 0x6 + 13.201x7 + 27.201x8 + 11.152x9 + 9.225x10 + 8.427x11 + 10.041x12 + 22.452x13 + 14.977x14 + 22.318x16, N = 32, r = 0.9963, S = 1.7668. Where r, S and N are regression coefficient, residual standard deviation and data number, respectively. Having tested the modeling by using back-propagation neural network (BPNN) and leave-one-out method, we got the correlation coefficient of cross validation, 0.989. PMID:12552880

Chen, G; Li, Z

1999-09-01

270

Immunolocalization of proteoglycans and bone-related noncollagenous glycoproteins in developing acellular cementum of rat molars  

Microsoft Academic Search

To elucidate the roles of proteoglycans (PGs), bone sialoprotein (BSP), and osteopontin (OPN) in cementogenesis, their distribution was investigated in developing and established acellular cementum of rat molars by an immunoperoxidase method. To characterize PGs, antibodies against five species of glycosaminoglycans (GAGs), chondroitin-4-sulfate (C4S), chondroitin-6-sulfate (C6S), unsulfated chondroitin (C0S), dermatan sulfate (DS), and keratan sulfate (KS) were used. Routine histological

T. Yamamoto; T. Domon; S. Takahashi; A. K. S. Arambawatta; M. Wakita

2004-01-01

271

The use of intraosseous screw for upper molar distalization: a case report.  

PubMed

The use of implants has made a major change in orthodontic treatment mechanics. They have replaced conventional unaesthetic and compliance dependent extraoral appliances with well accepted intraoral mechanics. Implants can be used in molar and canine distalization, intrusion and in extraoral force applications. In the present case report, treatment of a case using an intermaxillary fixation screw (IMF) will be presented. The treatment results will be evaluated using pretreatment, post distalization and post treatment cephalometric radiographs and dental casts. PMID:19212521

Polat-Ozsoy, Omür

2008-04-01

272

The Use of Intraosseous Screw for Upper Molar Distalization: A Case Report  

PubMed Central

The use of implants has made a major change in orthodontic treatment mechanics. They have replaced conventional unaesthetic and compliance dependent extraoral appliances with well accepted intraoral mechanics. Implants can be used in molar and canine distalization, intrusion and in extraoral force applications. In the present case report, treatment of a case using an intermaxillary fixation screw (IMF) will be presented. The treatment results will be evaluated using pretreatment, post distalization and post treatment cephalometric radiographs and dental casts.

Polat-Ozsoy, Omur

2008-01-01

273

Influence of molar ratio on Pd–Pt catalysts for methane combustion  

Microsoft Academic Search

The catalytic oxidation of methane was investigated over six catalysts with different palladium and platinum molar ratios. The catalysts were characterised by TEM, EDS, XPS, PXRD and temperature-programmed oxidation. The results suggest that in the bimetallic catalysts, an alloy between Pd and Pt was formed in close contact with the PdO phase, with an exception for the Pt-rich catalyst, where

K. Persson; A. Ersson; K. Jansson; J. L. G. Fierro; S. G. Järås

2006-01-01

274

Endodontic treatment of a mesotaurodont maxillary first molar: a case report.  

PubMed

Taurodontism is an abnormal morphological trait of tooth shape, which usually occurs in multi-rooted teeth. An enlarged pulp chamber and apical displacement of the pulpal floor are characteristics. Endodontic treatment ofa taurodont tooth may be very difficult because it requires special care in identifying and treatment of the complex root canal system. The endodontic treatment ofa taurodont maxillary first molar is presented. PMID:19772109

Gharagozloo, Salman; Faraghat, Sudeh; Jafarzadeh, Hamid

2009-09-01

275

[Volumetric verification of edema protection with Serrapeptase after third molar osteotomy].  

PubMed

Preventive edema protection using Serrapeptase after standardized one-stage osteotomy procedures of 4 third molars was verified by means of an opto-electronic measuring instrument. This measuring technique proved to be a sensitive tool for demonstrating the efficacy of Serrapeptase in reducing postoperative edema. Although statistically significant, the reduction of soft tissue swelling was only approximately 15% when compared with a patient group without Serrapeptase medication. PMID:1816962

Merten, H A; Müller, K; Drubel, F; Halling, F

1991-01-01

276

[Optimization of the surgical technic for extraction of the lower third molars].  

PubMed

The high incidence of third molar extraction is related to their frequent pathology. The use of an uncomplicated and reliable diagnostic and therapeutic protocol therefore became extremely important. The protocol has to include careful selection and preparation as well as the appropriate choice of instruments and surgical techniques. This is even more important, considering the elective nature of the procedure and the local and more rarely, systemic complications that could develop. PMID:2659960

Garattini, G; Piccoli, P; Grecchi, M T

1989-04-01

277

Strategies used to inhibit postoperative swelling following removal of impacted lower third molar  

PubMed Central

Postoperative swelling following different surgical strategies is an area of great interest. The main part of literature on the topic deals with swelling after extraction of low impacted third molar. In this review, we have analyzed publications of the last 20 years with a pubmed search using the following key words: impacted third molar, swelling third molar, wisdom tooth, edema jaw, corticosteroids and extraction third molar, antibiotic prophylaxis and tooth extraction. Attention has often been focused on corticosteroid therapy administered by diverse routes (orally, IV, IM, topically) and at different time schedules (before or after surgery or both). This investigation revealed how the use of different molecules and dosages makes the obtained results hardly comparable. Similar conclusions can be drawn from studies aimed at evaluating the efficacy of antibiotic therapy administered either before or after surgery. A complete review has also to take into account different surgical strategies used including various flaps, no traumatic osteothomy, and primary or secondary closure. The use of pharmacological therapy and application of an ice pack is critical in the postoperative period and has always provided positive results. However, even if it is difficult to come to definite conclusions, due to the variability of the design of studies analyzed, the postoperative discomfort identified with edema, pain and trismus following wisdom tooth removal is influenced by various factors such as the difficulty of the surgical procedure involved, age and gender of the patient, and experience of the surgeon. The pharmacological therapy when performed with corticosteroids seems to improve control of the postoperative swelling related with this kind of surgeries.

Sortino, Francesco; Cicciu, Marco

2011-01-01

278

Increased thermal stability of a poled electro-optic polymer using high-molar-mass fractions.  

PubMed

Polymer fractionation yields materials with higher average molar masses and thus substantially increased glass transition temperatures. We apply this technique to a photoaddressable polymer that exhibits high electro-optic coefficients, in order to enhance the thermal stability of the poled material. The degree of orientation of the dipolar chromophores is investigated with both pyroelectric and electro-optic measurements. The pyroelectric measurements at elevated temperatures show no significant contribution of beta relaxation as compared to alpha relaxation. PMID:15600428

Bertram, Ralph P; Benter, Nils; Apitz, Dirk; Soergel, Elisabeth; Buse, Karsten; Hagen, Rainer; Kostromine, Serguei G

2004-10-01

279

Parvalbumin and calretinin-immunoreactive trigeminal neurons innervating the rat molar tooth pulp  

Microsoft Academic Search

Calcium-binding proteins and neuropeptides were examined in trigeminal neuronal cell bodies retrogradely labeled with Fast blue (FB) from the maxillary molar tooth pulp of the rat. FB-labeled cells were located in the maxillary division of the trigeminal ganglion. ? 30 and 50% of the labeled cells were immunoreactive for parvalbumin and calcitonin gene-related peptide (CGRP), respectively. The coexpression of these

Hiroyuki Ichikawa; Toru Deguchi; Tadao Nakago; David M. Jacobowitz; Tomosada Sugimoto

1995-01-01

280

Calmodulin-like activity in a mineralising tissue: The rat molar tooth germ  

Microsoft Academic Search

Summary  Calmodulin, a calcium binding protein, has been implicated in the regulation of many calcium-dependent biological processes.\\u000a Since calcium has an important role in hard tissue genesis, both at intra- and extracellular levels, we anticipate that calcium\\u000a binding proteins may modulate this process. The present study investigated a mineralising tissue, the rat molar tooth germ,\\u000a to determine the presence of calmodulin-like

Michael J. Hubbard; Mark P. Bradley; Thomas B. Kardos; Ian T. Forrester

1981-01-01

281

Neonatal hamster molar tooth development: Extraction and characterization of amelogenins, enamelins, and soluble dentin proteins  

Microsoft Academic Search

Summary  Amelogenins, enamelins, and soluble dentin proteins were sequentially separated under dissociative conditions from morphologically\\u000a characterized molar tooth germs of 4-, 6-, and 7-day-old hamsters. Polyacrylamide gel electrophoretic, gel filtration chromatographic,\\u000a and amino acid compositional data of neonatal hamster amelogenin extracts were in general agreement with those obtained from\\u000a fetal bovine enamel under similar extraction conditions. As development progressed (e.g., 4

D. M. Lyaruu; A. Belcourt; A. G. Fincham; J. D. Termine

1982-01-01

282

The sedimentary features of Proterozoic microspar (Molar-tooth) carbonates in China and their significance  

Microsoft Academic Search

On the North China platform Molar-tooth (MT) carbon- ates were formed during 1600-650Ma (i.e. the Middle to Late Proterozoic), within various supercyclic sequences, such as the Changcheng, Jixian, Qingbaikou and Sinian Systems. Detailed field observations on the MT carbonate sections and microscopic studies show that MT carbonates may be divided into two major groups—autochthonous and allochthonous and 6 sub- groups

Meng Xianghua; Ge Ming

283

Inhibition of Mouse Molar Tooth Germ Morphogenesis in Organ Culture by Alanosine  

Microsoft Academic Search

Alanosine (2-amino-3-[hydroxynitrosoamino] propionic acid) an extracellular antitumor product of Streptomyces inhibits the in vitro morphogenesis of mouse molar tooth germs. Organ cultures prepared from 15- and 16-day-old C5 7BL\\/6J embryos were maintained on agar-solidified BME, supplemented with glutamine, gentamicin and fetal calf serum, in an incubation atmosphere of 5% CO2 and 95% air. At a concentration of 16 ?g\\/ml, alanosine

F. J. Dye; E. J. Kollar

1978-01-01

284

Physiological distal drift in rat molars contributes to acellular cementum formation.  

PubMed

Occlusal forces may induce the physiological teeth migration in humans, but there is little direct evidence. Rat molars are known to migrate distally during aging, possibly caused by occlusal forces. The purpose of this study was to determine if a reduction in occlusion would decrease teeth migration and affect associated periodontal structures such as cementum. To reduce occlusal forces, the right upper first molar (M1) in juvenile rats was extracted. The transition of the position of upper second molar (M2) and formation of M2 cementum was followed during aging. From the cephalometric analyses, upper M2 was located more anterior compared with the original position with aging after M1 extraction. Associated with this "slowing-down" of the physiological drift, cementum thickness on distal surface, but not on mesial surface, of M2 root was significantly increased. The accumulation of alizarin red as vital stain indicative of calcification, was observed in the distal cementum of M2 root only on the side of M1 extraction. Extraction of M1 that results in less functional loading, distinctly attenuates the physiological drift only in the upper dentition. The decreased physiological drift appears to activate acellular cementum formation only on distal surface of M2 root, perhaps due to reduced mechanical stress associated with the attenuated distal drift. In conclusion, the physiological distal drift in rat molars appears to be largely driven by the occlusal force and also affects the formation of acellular cementum. These findings provide additional direct evidence for an important role of occlusal forces in tooth migration. PMID:23775928

Tsuchiya, Shinobu; Tsuchiya, Masahiro; Nishioka, Takashi; Suzuki, Osamu; Sasano, Yasuyuki; Igarashi, Kaoru

2013-08-01

285

Evaluation of a one-appointment formocresol pulpectomy technique for primary molars  

Microsoft Academic Search

The purpose of this study was to evaluate the relative amount of root resorption in nonvital primary teeth after treatment with a 1-appointment formocresol pulpectomy. Thirty-seven children ranging in age from 2 years, 10 months to 8 years, 10 months received 41 pulpectomies in nonvital primary molars. At an initial follow-up examination, 6-36 months posttreatment (mean = 21 months), 80.5%

Jerome S. Casper

1985-01-01

286

Absorption of Nickel, Chromium, and Iron by the Root Surface of Primary Molars Covered with Stainless Steel Crowns  

PubMed Central

Objective. The purpose of this study was to analyze the absorption of metal ions released from stainless steel crowns by root surface of primary molars. Study Design. Laboratory research: The study included 34 primary molars, exfoliated or extracted during routine dental treatment. 17 molars were covered with stainless-steel crowns for more than two years and compared to 17 intact primary molars. Chemical content of the mesial or distal root surface, 1?mm apically to the crown or the cemento-enamel junction (CEJ), was analyzed. An energy dispersive X-ray spectrometer (EDS) was used for chemical analysis. Results. Higher amounts of nickel, chromium, and iron (5-6 times) were found in the cementum of molars covered with stainless-steel crowns compared to intact molars. The differences between groups were highly significant (P < .001). Significance. Stainless-steel crowns release nickel, chromium, and iron in oral environment, and the ions are absorbed by the primary molars roots. The additional burden of allergenic metals should be reduced if possible.

Keinan, David; Mass, Eliyahu; Zilberman, Uri

2010-01-01

287

Acetaminophen, pesticide, and diethylhexyl phthalate metabolites, anandamide, and fatty acids in deciduous molars: potential biomarkers of perinatal exposure.  

PubMed

The developing fetus is particularly vulnerable to adverse effects from pharmaceutical and exogenous chemical exposure. Deciduous teeth primarily form over specific periods from the second trimester in utero through the months after birth. We hypothesized that organic chemicals or their metabolites circulating in the bloodstream may sorb into forming dental tissues and remain stored in the tooth thereafter. Our aims were to devise analytical and preparation methods for potentially toxic or beneficial organic chemicals or metabolites in deciduous teeth and to estimate their detection frequencies. The analgesic acetaminophen was stored at greater concentration in a child's second molar than a first molar, consistent with intake, suggesting that acetaminophen concentration in molars may be a biomarker of acetaminophen exposure during molar formation. Chemicals detected by liquid chromatography/tandem mass spectrometry in molars of 21 typically developing children include the endocannabinoid anandamide (86% of children), acetaminophen (43%), and specific metabolites mono-2-ethylhexyl phthalate (MEHP, of plasticizer di-2-ethylhexyl phthalate, 29%), 3,5,6-trichloro-2-pyridinol (TCPy, of organophosphate (OP) insecticide chlorpyrifos, 10%), and 2-isopropyl-6-methyl-4-pyrimidinol (IMPy, of OP insecticide diazinon, 10%). None of these chemicals has previously been detected in human teeth. Molars from the two oldest subjects contained the largest concentrations of MEHP, TCPy, and IMPy. Potentially protective fatty acids detected by gas chromatography/mass spectrometry after derivatization include docosahexaenoic (19%), arachidonic (100%), and linoleic (100%). Validation studies are necessary to verify that each detected chemical in molars provides a biomarker of perinatal exposure. PMID:22805989

Camann, David E; Schultz, Stephen T; Yau, Alice Y; Heilbrun, Lynne P; Zuniga, Michelle M; Palmer, Raymond F; Miller, Claudia S

2013-03-01

288

[First permanent molar caries: a case study of Moroccan children between 6 and 15 year-old].  

PubMed

It is a transverse descriptive study realized from clinical files of 100 Moroccan children aged between 6 and 15 year-old having consulted the Rabat Dental Hospital (U.T.H. Ibn Sina) in Morocco between January and December 2009. The criteria of inclusion are age, Moroccan origin, first four permanent molars having made their eruption and a complete clinical file. The criteria of exclusion are the non-eruption of a first permanent molar and an incomplete clinical file. The clinical parameters are: age, sex, tooth brushing, quality of alimentation and the condition of the first permanent molars (caries, extraction, filling). The results showed that 65% of the children between 6 and 15 years have at least a first decayed permanent molar. Eight per cent of the children have at least a filling material on the first permanent molar and 4% of the children have already extracted a first permanent molar. The caries touch both sexes, both right and left sectors and both superior and lower arches without statistically significant difference (p > 0.05). The presence of the caries increased, on the other hand, with the age (p < 0.05). The relation between presence of caries, tooth brushing and quality of alimentation is not significant (p < 0.05). These results are in accordance with numerous studies and show a particular cario-sensibility of the first permanent molar. PMID:23513507

Zouaidi, K; Chala, S; Ameziane, R; Chhoul, H

2012-12-01

289

Brief communication: dental development and enamel thickness in the Lakonis Neanderthal molar.  

PubMed

Developmental and structural affinities between modern human and Neanderthal dental remains continue to be a subject of debate as well as their utility for informing assessments of life history and taxonomy. Excavation of the Middle Paleolithic cave site Lakonis in southern Greece has yielded a lower third molar (LKH 1). Here, we detail the crown development and enamel thickness of the distal cusps of the LKH 1 specimen, which has been classified as a Neanderthal based on the presence of an anterior fovea and mid-trigonid crest. Crown formation was determined using standard histological techniques, and enamel thickness was measured from a virtual plane of section. Developmental differences include thinner cuspal enamel and a lower periodicity than modern humans. Crown formation in the LKH 1 hypoconid is estimated to be 2.6-2.7 years, which is shorter than modern human times. The LKH 1 hypoconid also shows a more rapid overall crown extension rate than modern humans. Relative enamel thickness was approximately half that of a modern human sample mean; enamel on the distal cusps of modern human third molars is extremely thick in absolute and relative terms. These findings are consistent with recent studies that demonstrate differences in crown development, tissue proportions, and enamel thickness between Neanderthals and modern humans. Although overlap in some developmental variables may be found, the results of this and other studies suggest that Neanderthal molars formed in shorter periods of time than modern humans, due in part to thinner enamel and faster crown extension rates. PMID:18711737

Smith, T M; Harvati, K; Olejniczak, A J; Reid, D J; Hublin, J-J; Panagopoulou, E

2009-01-01

290

Detection of a secondary mesio-buccal canal in maxillary first molar: A comparative study  

PubMed Central

Aim: The purpose of this study was to clarify detection characteristics of the secondary mesio-buccal canal in maxillary first molars using various methods. Materials and Methods: The root canal system of 86 extracted human maxillary first molars was inspected using micro-focus-computed tomography to accurately determine the number of canals. Radiographs or floors of the pulp chamber for all samples were observed for the secondary mesio-buccal canal with computed tomography for dentistry, digital dental radiography, magnifier, or the naked eye. Sensitivity, specificity, positive, and negative predictive values and diagnostic accuracy for these four methods were investigated using the results from the micro-focus-computed tomography inspection as the gold standard. All samples of each method were observed by 10 endodontists. Using these results, the ?2 test was used to compare and analyze differences between the various conditions (P<0.05). Results: The secondary mesio-buccal canal could be recognized in 60.9% of samples with the micro-focus-computed tomography. No significant difference was seen between efficiencies of the computed tomography for dentistry and the micro-focus-computed tomography. The computed tomography for dentistry was superior to the other three methods. Conclusion: Detectability of the secondary mesio-buccal canal in the maxillary first molar was superior using dental-computed tomography compared to digital dental radiography, magnification telescope, and the naked eye.

Hosoya, Noriyasu; Yoshida, Takumasa; Iino, Fumiaki; Arai, Takashi; Mishima, Akira; Kobayashi, Kaoru

2012-01-01

291

Randomized Split-Mouth Study on Postoperative Effects of Palmitoylethanolamide for Impacted Lower Third Molar Surgery  

PubMed Central

The aim of this study was to assess the efficacy of Normast 300?mg in reducing swelling and pain after the surgical extraction of impacted lower third molars. Materials and Methods. A randomized, split-mouth, single-blind study was conducted on 30 patients between 18 and 30 years of age requiring lower third molar extraction. Patients underwent bilateral extractions in a randomized sequence, one extraction being performed under Normast treatment. The Normast treatment involved 2 tablets a day for 15 days. The parameters assessed at each procedure were trismus, swelling, pain, NSAID consumption, postoperative complications, drug tolerability, and safety. The results obtained were processed using repeated measures analysis of variance. Results. Perceived postoperative pain was reportedly significantly milder on Normast treatment than control. The trend of the means differed over time (P < .0001) and between the two extraction groups (P < .0221). On the other hand, for edema and trismus, the trend differed over time for both groups but did not differ between the two groups. Discussion. Our analyses indicate that patients experienced significantly less postoperative pain when they were treated with Normast. Conclusions. Administering Normast improves the postoperative course—in terms of pain—after lower third molar extraction.

Bacci, Christian; Cassetta, Giulia; Emanuele, Bruno; Berengo, Mario

2011-01-01

292

Histopathological and radiographic evaluation of rat molar teeth after traumatic injury-a pilot study  

PubMed Central

Objective: Radiographic and histopathological evaluation of mechanical trauma on the development of maxillary molars in rat. Materials and Methods: Experimental study with 7-day-old five new born Wistar rats. Trauma induced on 7th postnatal day with #55 K file. Right first molar region of the maxilla was the experimental side, and the left side as control. Each animal was sacrificed for histopathological observation on 8th day (immediately next day of injury), 10th day (after 3 days of injury), 13th day (Enamel completion), 19th day (Emergence into oral cavity) and 42nd day when all the teeth came into functional occlusion. Results: On the 42nd day experimental side of the study, the 1st molar tooth had not erupted and the radiographs taken revealed conglomerate mass suggestive of complex odontome. Reduced tooth size, altered enamel and dentin formation, abscess formation and complex odontome like structure were observed histopathologically. Conclusion: The diversity of morphlogical and histopathological changes to intrusive force implies intricate mechanism involved in tooth development.

Prasanth, T; Saraswathi, TR

2012-01-01

293

The Long-Term Effects of Mandibular Distraction Osteogenesis on Developing Deciduous Molar Teeth  

PubMed Central

Background. Many studies have demonstrated the effectiveness of mandibular distraction osteogenesis (MDO) in alleviating the micrognathia-associated upper airway obstruction but very few studies have focused on long-term dental outcomes. Objective. To report the effect of MDO on developing deciduous molars in the distraction area. Methods. A retrospective chart review was performed to identify patients with Pierre Robin sequence who underwent MDO with documented long-term dental assessments. Results. Ten children (mean age at surgery 69.8 days; 6 boys and 4 girls) were included for analysis. All patients underwent bilateral MDO with an inverted L-shaped osteotomy to avoid injuring tooth buds. The dental developmental stage was primary dentition in all children. Overall, 3 patients developed minor dental problems involving 4 molar teeth (2 root malformations and 2 shape anomalies) but they did not require any interventions. Conclusion. Significant primary molar developmental complications were not seen in our patients. The use of internal distractor device with an inverted L-shaped osteotomy seems to be a safe surgical approach in regards to dental outcomes.

Hong, Paul; Graham, Elise; Belyea, James; Taylor, S. Mark; Kearns, Donald B.; Bezuhly, Michael

2012-01-01

294

Histological evaluation of pulp tissue from second primary molars correlated with clinical and radiographic caries findings  

PubMed Central

Background: Managing dental caries in young children is demanding due to the elusions present on the right diagnostic criteria for treatment. The present study evaluated the histological status of pulp tissues extracted from primary second molar with caries involvement. Histological findings are correlated with clinical and radiographic assessment. Materials and Methods: Simple experimental study was conducted on upper or lower second primary molars with occlusal (22 teeth) or proximal (22 teeth) dental caries. Selected children were below 6 years of age. Percentage of caries involvement, residual dentin thickness (RDT), radiographic assessment of interradicular and periapical areas, clinical caries depth and signs and symptoms are the parameters considered for comparing with the histological findings. The specimens were grouped based on the nature of the inflammatory process as acute or chronic. The data were analyzed by Student t-test to compare histological types of inflammation with clinical parameters. P value < 0.05 was considered as significant. Results: Four cases revealed severe acute inflammation in coronal and relatively mild acute inflammation in radicular pulp. In the rest of the specimen coronal and radicular pulp had similar acute or chronic inflammatory changes. Histological evidence of pulpitis correlated with dental caries depth of ?80%, RDT of ?1 mm, radiographic rarefactions in the interradicular regions and symptoms of pain. Conclusion: Primary second molars with more than two-third caries involvement with symptoms of pain histologically showed inflammation of both coronal and radicular pulp tissues in all cases.

Gopinath, Vellore Kannan; Anwar, Khurshid

2014-01-01

295

Resin-modified glass ionomer restorations in primary molars: a comparison of three in vitro procedures.  

PubMed

In recent years, interest in the use of glass ionomer cements as a restorative material has been increased. The aim of this in vitro study was to evaluate the microleakage of a glass ionomer restorative material (Vitremer TM) in Class V cavities of primary molars using three different application procedures. The experimental material consisted of 24 freshly extracted human primary molars in which a standardized class V cavities were prepared and restored with Vitremer utilizing three different application procedures (Vitremer with conditioner, with conditioner and primer or with primer). Teeth were covered with green stick compound and nail polish except approximately 1 mm from the class V cavities margins. Later, teeth were immersed in 5% methylene blue for 4 hours, rinsed with water and embedded in acrylic resin. The marginal microleakage was assessed according to the degree of dye penetration of the occlusal and cervical margins. The results showed no significant difference between the three different application procedures. However, the occlusal margin microleakage was significantly higher than the cervical margin (P = 0.0079). It was concluded that using different application procedures of Vitremer, including the recommendations of the manufacturer does not affect microleakage of class V cavities in primary molars. PMID:9161211

al-Obaidi, F F; Salama, F S

1996-01-01

296

Determination of the molar extinction coefficient for the ferric reducing/antioxidant power assay.  

PubMed

The FRAP reagent contains 2,4,6-tris(2-pyridyl)-s-triazine, which forms a blue-violet complex ion in the presence of ferrous ions. Although the FRAP (ferric reducing/antioxidant power) assay is popular and has been in use for many years, the correct molar extinction coefficient of this complex ion under FRAP assay conditions has never been published, casting doubt on the validity of previous calibrations. A previously reported value of 19,800 is an underestimate. We determined that the molar extinction coefficient was 21,140. The value of the molar extinction coefficient was also shown to depend on the type of assay and was found to be 22,230 under iron assay conditions, in good agreement with published data. Redox titration indicated that the ferrous sulfate heptahydrate calibrator recommended by Benzie and Strain, the FRAP assay inventors, is prone to efflorescence and, therefore, is unreliable. Ferrous ammonium sulfate hexahydrate in dilute sulfuric acid was a more stable alternative. Few authors publish their calibration data, and this makes comparative analyses impossible. A critical examination of the limited number of examples of calibration data in the published literature reveals only that Benzie and Strain obtained a satisfactory calibration using their method. PMID:21669177

Hayes, William A; Mills, Daniel S; Neville, Rachel F; Kiddie, Jenna; Collins, Lisa M

2011-09-15

297

Accuracy of the Dentaport ZX apex locator for working length determination when retreating molar root canals.  

PubMed

The aim of this study was to evaluate the accuracy of the Dentaport ZX apex locator for working length determination during root canal retreatment of mandibular molars. Fifteen extracted mandibular first molars with separate mesial canals and apical foraminae and one distal canal were selected. The mesiobuccal and distal canals were investigated; the length with the file tip at the major diameter was defined as the tooth length (TL). The canals were prepared with ProTaper files to 1?mm short of this and filled with gutta-percha and AH Plus sealer. One week later, the root fillings were removed using ProTaper retreatment files. Tooth length was remeasured and recorded as the retreatment tooth length (RTL). Then electronic measurements were taken at the major (electronic apex locator (EAL) major) and minor (EAL minor) foraminae as suggested by the instrument display. These lengths were compared with RTL and measurements 0.5 and 1?mm short of this distance. For both canals, no significant difference was found between RTL and EAL major, and 0.5?mm short of RTL and EAL minor (P?>?0.05). There were significant differences found between all other readings. The Dentaport ZX could not detect the minor foramen accurately but was able to indicate the major foramen in molars undergoing a root canal retreatment procedure. PMID:24697957

Cimilli, Hale; Aydemir, Seda; Ar?can, Burcin; Mumcu, Gonca; Chandler, Nicholas; Kartal, Nevin

2014-04-01

298

Ice nucleation in aqueous solutions of poly[ethylene glycol] with different molar mass  

NASA Astrophysics Data System (ADS)

Homogeneous ice nucleation was investigated in aqueous solutions of poly[ethylene glycol] (PEG) with a molar mass between 300 and 6000 g mol-1. Experiments were performed with a differential scanning calorimeter using emulsified aqueous PEG solutions with concentrations of 0-44 wt %. Equilibrium phase transition temperatures are determined and discussed, in particular the simultaneous occurrence of metastable and stable eutectic temperatures. The observed homogeneous freezing temperatures of ice reveal a continuous increase in the supercooling of PEG solutions with increasing molar mass of the PEG. The freezing behavior was investigated within the framework of water-activity-based ice nucleation theory. The latter predicts that homogeneous ice nucleation in aqueous solutions is independent of the nature of the solute, but depends only on the water activity of the solution. Water activity data of various PEG solutions in the stable and supercooled range were compared. It was found that the water activity of PEG solutions decreases with decreasing temperature. This trend is stronger for the PEGs of larger molar mass, and can explain why solutions of larger PEGs supercool more readily. Our study shows that the predictions of water-activity-based ice nucleation theory are consistent with the observed freezing behavior and with the thermodynamic properties of PEG solutions. It is also in agreement with the suggestion of a thermodynamic control of ice nucleation in aqueous systems due to the existence of a liquid phase spinodal.

Zobrist, Bernhard; Weers, Uwe; Koop, Thomas

2003-06-01

299

Surgical extraction of impacted inferior third molars at risk for inferior alveolar nerve injury.  

PubMed

The objective of the study was to prospectively assess the intraoperative findings and the radiographic signs of a study population of patients with impacted third molars at risk of inferior alveolar nerve injury. One hundred thirty-four patients with impacted mandibular third molars at risk for nerve injury were included in the study. Radiographic signs of possible close relationship between the 2 structures and intraoperative exposition or damage of the inferior alveolar nerve were recorded. The follow-up controls comprised clinical examinations and assessment for the sensation of the lower lip and chin. In 24 patients, a real contiguity was encountered between the third molars and nerve. Among these, intraoperative neural exposition was observed in 19 patients. Four patients complained of postoperative temporary hypoesthesia. No deficit of sensibility was found in cases with no exposition of the nerve. The accidental exposition of the inferior alveolar nerve is associated with an increased risk for neural injuries. At panoramic radiograph, the presence of signs of bifid and radiolucent apex, superimposition, and radiolucent root band should be considered at high risk for neural damage. PMID:21119486

Gallesio, Cesare; Berrone, Mattia; Ruga, Emanuele; Boffano, Paolo

2010-11-01

300

Influence of surrounding wall thickness on the fatigue resistance of molars restored with ceramic inlay.  

PubMed

The purpose of this study was to evaluate the influence of buccal and lingual wall thickness on the fatigue resistance of molars restored with CAD/CAM ceramic inlays. Forty human third molars were selected and divided into 4 groups, according to the remaining surrounding wall thickness chosen for inlay preparation (n = 10): G1, 2.0 mm; G2, 1.5 mm; G3, 1.0 mm; G4, 0.5 mm. All inlays were made from feldspathic ceramic blocks by a CAD/CAM system, and cemented adhesively. After 1 week stored in distilled water at 37 °C, the specimens were subjected to fatigue testing under the following protocol: 5Hz; pre-load of 200 N for 5,000 cycles, followed by increasing loads of 400, 600, 800, 1000, 1200 and 1400 N for 30,000 cycles each. The specimens were cycled until failure or completion of 185,000 cycles. The survival rate of the groups was compared using the Kaplan-Meier survival curves (p > 0.05). All specimens withstood the fatigue protocol (185,000 cycles), representing a 100% survival rate. The Kaplan-Meier survival curves showed no difference between groups. It can be concluded that the remaining tooth wall thickness did not influence the fatigue resistance of molars restored with CAD/CAM ceramic inlays. PMID:24918366

Shibata, Shizuma; Gondo, Renata; Araújo, Elito; Roesler, Carlos Rodrigo De Mello; Baratieri, Luiz Narciso

2014-06-11

301

Buccal Injection of 2% Lidocaine With Epinephrine for the Removal of Maxillary Third Molars  

PubMed Central

The aim of the study was to demonstrate if 2% lidocaine hydrochloride with 1?:?200,000 epinephrine could provide palatal anesthesia in maxillary tooth removal with a single buccal injection. The subjects included in the clinical study were those requiring extraction of the maxillary third molar of either side. For the purpose of comparison, the sample was randomly divided into 2 main groups: group 1 (study group) included 100 subjects who were to receive a single injection before extraction, and group 2 (control group) included 100 subjects who were to receive a single buccal injection and a single palatal injection before extraction. After 5 minutes the extraction was performed. All patients were observed for Faces Pain Scale during extraction and asked for the same on a 100-mm visual analog scale after extraction. According to visual analog scale and Faces Pain Scale scores, when maxillary third molar removal without palatal injection (study group) and with palatal injection (control group) were compared the difference was not statistically significant (P > .05). Removal of maxillary third molars without palatal injection is possible by depositing 2 mL of 2% lidocaine hydrochloride with 1?:?200,000 epinephrine to the buccal vestibule of the tooth.

Yadav, Sunil; Verma, Ajay; Sachdeva, Akash

2013-01-01

302

Comparative analysis of preemptive analgesic effect of tramadol chlorhydrate and nimesulide following third molar surgery.  

PubMed

The aim of this prospective, randomized, controlled, paired trial was to perform a comparative analysis of the preemptive analgesic effect of nimesulide and tramadol chlorhydrate during third molar surgery. The study was carried out between March and November 2009, involving 94 operations in 47 male and female patients with bilateral impacted lower third molars in comparable positions. The sample was divided into two groups. Group A received an oral dose of 100 mg of nimesulide 1 h prior to surgery. Group B received an oral dose of 100 mg of tramadol chlorhydrate 1 h prior to surgery. The following aspects were evaluated in the postoperative period: adverse effects of the drugs; amount of rescue medication used (acetaminophen 750 mg); and pain 5, 6, 24, 36, 48, 60, 72 and 84 h after surgery using a visual analog pain scale. Peak pain occurred 5 h after surgery in both groups, with a mean pain score of 2.3 in Group A and 3.0 in Group B; this difference did not achieve statistical significance (p > 0.141). Based on the sample studied, nimesulide and tramadol chlorhydrate demonstrate similar preemptive analgesic effects when used in lower third molar surgeries. PMID:22421470

da Costa Araújo, Fábio Andrey; de Santana Santos, Thiago; de Morais, Hécio Henrique Araújo; Laureano Filho, José Rodrigues; de Oliveira E Silva, Emanuel Dias; Vasconcellos, Ricardo José Holanda

2012-12-01

303

PrPc is temporospatially expressed in molar development of rats.  

PubMed

Odontogenesis, tooth development, is derived from two tissue components: ectoderm and neural crest-derived mesenchyme. Cyto-differentiation of odontogenic cells during development involves time-dependent and sequential regulation of genetic programs. This study was conducted to detect molecules implicated in cyto-differentiation of developing molar germs of rats. Differential display-PCR revealed that PrP(c) was differentially expressed between cap/early bell-staged germs (maxillary 3rd molar germs) and root formation-staged germs (maxillary 2nd molar germs) at postnatal day 9. Both levels of PrP(c) mRNA and protein expression were higher in the root formation stage than the cap/early bell stage and increased in a time-dependent manner. Immunofluorescence revealed for the first time that PrP(c) was not localized in the enamel organ, but localized in dental follicular cells for the development of the periodontal ligament and cementum as well as odontoblasts, both of which are of neural crest origin. These results suggest that the physiological functions of the PrP(c) in tooth development may be implicated in the differentiation of neural crest-derived mesenchyme including the periodontal tissues for root formation rather than epithelial tissue. PMID:24127188

Yoo, H I; Jang, S M; Kang, J H; Kim, M S; Koh, J T; Jung, J Y; Kim, W J; Oh, W M; Kim, S H

2013-12-01

304

Investigation of third molar impaction in Turkish orthodontic patients: Prevalence, depth and angular positions  

PubMed Central

Objective: We aimed to investigate the prevalence, distribution, angular position, and depth of third molar impaction in a Turkish orthodontic patient population. Materials and Methods: We retrospectively reviewed the panoramic radiographs, intraoral photographs, and dental casts of 207 patients (62 men and 145 women; age 20-39 years) who had undergone orthodontic treatment at a university department of orthodontics for impacted third molars (ITMs). A comprehensive chart review of all subjects was conducted. Patient and treatment-related data were recorded in a digital database for comparative analysis. Results: The prevalence of ITMs was 54.1%, and no statistically significant gender differences were evident (61.3% in men and 51.0% in women; P = 0.23). The frequency of maxillary ITMs was 49.3% (148 of 300 teeth) while that of mandibular ITMs was 50.7% (152 of 300 teeth). The most frequently observed angulations of impaction were mesioangular for the mandible (65.1%), and distoangular for the maxilla (64.2%). Of all the ITMs analysed, 61% were partially buried in bone and 39% were completely buried. Conclusions: Third molar impaction was evident in 54.1% of a group of Turkish orthodontic patients aged 20-39 years, and there was no statistically significant gender bias. Mesioangular and distoangular inclinations were the most common in the mandible and the maxilla, respectively.

Topkara, Ahu; Sari, Zafer

2013-01-01

305

Permanent molar pulpotomy with a new endodontic cement: A case series  

PubMed Central

The aim of this case series was to determine the clinical and radiographic success rate of pulpotomy, with new endodontic cement (NEC), in human mature permanent molar teeth. Twelve molars with established irreversible pulpitis were selected from patients 14 – 62 years old. The selection criteria included carious pulp exposure with a positive history of lingering pain. After isolation, caries removal, and pulp exposure, pulpotomy with NEC was performed and a permanent restoration was immediately placed. At the first recall (+1 day) no patients reported postoperative pain. One wisdom tooth had been extracted after two months because of failure in coronal restoration. Eleven patients were available for the second recall, with a mean time of 15.8 months. Clinical and radiographic examination revealed that all teeth were functional and free of signs and symptoms. Histological examination of the extracted teeth revealed complete dentin bridge formation and a normal pulp. Although the results favored the use of NEC, more studies with larger samples and a longer recall period were suggested, to justify the use of this novel material for treatment of irreversible pulpitis in human permanent molar teeth.

Asgary, Saeed; Ehsani, Sara

2009-01-01

306

“Molar-tooth” structures: A geochemical perspective on a Proterozoic enigma  

NASA Astrophysics Data System (ADS)

“Molar-tooth” structures are microcrystalline calcite-filled features of long-debated origin that are common in Mesoproterozoic and early Neoproterozoic fine-grained, shallow-water carbonates. We have constrained the environment of their formation from the standpoint of depositional and diagenetic conditions inferred on the basis of petrographic and geochemical data derived from examples in the Helena Formation, a calcareous marine interval within the Mesoproterozoic Belt Supergroup. The collective data set supports an early-diagenetic origin for molar-tooth structures and implies environmental factors that promoted rapid precipitation of calcite into CO2-generated voids in cohesive muds. We propose that the temporally restricted distribution of molar-tooth structures in the geologic record reflects a unique combination of the environmental parameters that control their formation. Of these factors, the most fundamental include CaCO3 saturation and redox conditions in shallow marine waters that promote prolific carbonate production, tectonic quiescence and the availability of extensive epicratonic sites for carbonate accumulation, and the absence of bioturbators.

Frank, Tracy D.; Lyons, Timothy W.

1998-08-01

307

Root and canal morphology of mandibular second molar in an Iranian population by clearing method.  

PubMed

Statement of Problem: The knowledge of the pulp anatomy plays an important role in the success of endodontic treatments. Purpose: The aim of this study was to determine the root and canal morphology of the mandibular second molar teeth in an Iranian population. Material and Methods: One hundred intact human mandibular second molars were collected. The teeth were examined visually and the number of their roots were recorded. The teeth were covered using of lacquer. Access cavities were prepared and the pulp tissue was dissolved by sodium hypochlorite. The apices were covered with the glue and the root canals were injected with the methylene blue and were decalcified with 10% nitric acid, dehydrated with ascending concentrations of alcohol and rendered clear by immersion in methyl salicylate. The following remarks were evaluated: (i) number of root canals per tooth; (ii) number of canals per root; (iii) canal configuration in each root. Results: Of 100 examined teeth; 6% had one root, 89% had two roots, 2% had three roots and 3% had C-shaped roots. The teeth were classified based on the number of canals: 3 % had single canal, 6 % two canals, 54% three canals, 34% four canals, whilst 3 % had C-shaped roots. Based on the Vertucci classification, the most prevalent canal configuration in the mesial root was type II and in the distal root was type I. Conclusion : Iranian mandibular second molar teeth exhibit features which are similar to the average Jordanian, Caucasian and Burmese root and canal morphology. PMID:24724124

Zare Jahromi, M; Jafari Golestan, F; Mashhadi Esmaeil, M; Moouavizahed, Sh; Sarami, M

2013-06-01

308

Influence of eruption stage and biofilm accumulation on occlusal caries in permanent molars: a generalized estimating equations logistic approach.  

PubMed

The aim of this study was to estimate the independent effects of biofilm accumulation and eruption stage on the occurrence of active caries lesions on occlusal surfaces of permanent molars. The sample consisted of 298 schoolchildren (6-15 years) who were examined by a calibrated examiner at a dental unit, using artificial light, a dental mirror and a WHO probe. The occurrence of visible biofilm on occlusal surfaces and the eruption stage of each permanent molar were recorded. After professional prophylaxis and air drying, the occlusal surfaces were classified as sound, caries-inactive or caries-active. To evaluate the association of eruption stage and biofilm accumulation with active caries lesions, a logistic regression model was used. Since data were clustered, odds ratios were obtained using generalized estimating equations with a logistic link function. 1,779 permanent molars were examined. All eruption stages were associated with active caries lesions. After adjustment for biofilm accumulation and type of molar, molars with occlusal surfaces partially exposed to the oral cavity were 63.6 times more susceptible to caries activity than molars with full occlusion (95% CI = 22.0-183.7). After adjustment for eruption stage and type of molar, teeth with a high degree of biofilm accumulation were 14.5 times more susceptible to caries activity than those without visible biofilm accumulation (95% CI = 6.5-32.4). No association between active caries and hardly detectable biofilm was found in this population. The present study found that the eruption stage of permanent molars is strongly associated with active caries lesions, adjusted for biofilm accumulation and type of molar. PMID:23221986

Zenkner, J E A; Alves, L S; de Oliveira, R S; Bica, R H; Wagner, M B; Maltz, M

2013-01-01

309

Does the Relationship between Retained Mandibular Third Molar and Mandibular Angle Fracture Exist? An Assessment of Three Possible Causes  

PubMed Central

The objective of this study is to discuss problems associated with dental retention through three clinical cases of mandible fractures related to the presence of retained lower third molars, emphasizing the possibility of mandible fractures resulting from this or from the extraction procedure. The three evaluated patients had a fracture in the mandible angle. The third molars were present in all the cases, as was the relationship of the fracture with the teeth. After evaluating the three cases and reviewing literature, it is believed that the presence of the retained lower third molars and the surgical procedures for their extraction increase the risk of mandible angle fractures.

Duarte, Bruno G.; Assis, Diogo; Ribeiro-Junior, Paulo; Goncales, Eduardo Sanches

2012-01-01

310

Spiral Computed Tomographic Evaluation and Endodontic Management of a Mandibular Second Molar with Four Roots. A Case Report and Literature Review  

PubMed Central

The vast majority of mandibular second molars have two roots with three root canals; however, variations in molar root canal anatomy are not uncommon. To the best of our knowledge, four rooted mandibular second molar with three mesial roots and one distal root has never been reported. Herein, we present the endodontic management of a four rooted mandibular second molar tooth, diagnosed with the assistance of spiral computed tomography (SCT) with a brief review of literature.

Purra, Aamir Rashid; Mushtaq, Mubashir; Robbani, Irfan; Farooq, Riyaz

2013-01-01

311

A partial molar volume for ZnO in silicate melts.  

NASA Astrophysics Data System (ADS)

Trace elements in igneous petrology have, in comparison with major elements, a relevance in the petrogenetic modelling of magmatic differentiation that far outweighs their relative abundance. Optimal use of the information contained in trace element variations within igneous phases requires an accurate description of their partitioning behaviour as a function of phase composition and structure, as well as temperature and pressure. In this manner, the partial molar thermodynamic properties of trace elements in silicate melts may contribute to the petrogenetic modelling of such systems. With this in mind, a series of investigations into the partial molar properties of trace elements in silicate melts have been carried out in recent years. Here we extend this work to the analysis of the volumetric properties of ZnO in silicate melts. Densities of 8 Zn-bearing silicate melts have been determined in air in the temperature range of 1363 to 1850 K. The compositional joins investigated (sodium disilicate (NS2) - ZnO; anorthite-diopside 1 bar eutectic (AnDi) - ZnO; and diopside - petedunnite) were chosen based on the pre-existing experimental density data set, their petrological relevance and to provide a test for significant compositionally induced variations in the structural role of ZnO. The ZnO concentrations investigated range up to 25 mol% for sodium disilicate, 20 mol% for the anorthite-diopside 1 atm eutectic and 100 mol% petedunnite. Molar volumes and expansivities of all melts have been derived. The molar volumes of the present liquids all decrease with increasing ZnO content. The partial molar volume of ZnO derived here from the volumetric measurements for each binary system is the same within error. A multicomponent fit to the volumetric data for all compositions yields a value of 14.141(0.730) cm3.mol-1 at 1300 K. We find, herewith, no volumetric evidence for compositionally-induced coordination number variations for ZnO in alkali-bearing versus alkali-free silicate melts.

Ledda, B.; Potuzak, M.; Dingwell, D. B.; Courtial, P.

2004-12-01

312

MOLAR Progress Report 1/1997. March 1996 - March 1997. Measuring and modelling the dynamic responce of remote mountain lake ecosystems to environmental change: A programme of Mountain Lake Research - MOLAR.  

National Technical Information Service (NTIS)

MOLAR (Mountain Lake Research) is an extensive European cooperative research project with 23 partners. It is funded within the European Commission Framework Programme IV: Environment and Climate with assistance from INCO. It is coordinated by the Environm...

B. M. Wathne

1997-01-01

313

Comparison of tooth displacement between buccal mini-implants and palatal plate anchorage for molar distalization: a finite element study.  

PubMed

The purposes of this study were to mechanically evaluate distalization modalities through the application of skeletal anchorage using finite element analysis. Base models were constructed from commercial teeth models. A finite element model was created and three treatment modalities were modified to make 10 models. Modalities 1 and 2 placed mini-implants in the buccal side, and modality 3 placed a plate on the palatal side. Distalization with the palatal plate in modality 3 showed bodily molar movement and insignificant displacement of the incisors. Placing mini-implants on the buccal side in modalities 1 and 2 caused the first molar to be distally tipped and extruded, while the incisors were labially flared and intruded. Distalization with the palatal plate rather than mini-implants on the buccal side provided bodily molar movement without tipping or extrusion. It is recommended to use our findings as a clinical guide for the application of skeletal anchorage devices for molar distalization. PMID:22051536

Yu, Il-Jun; Kook, Yoon-Ah; Sung, Sang-Jin; Lee, Kee-Joon; Chun, Youn-Sic; Mo, Sung-Seo

2011-11-01

314

Dislocation of an upper third molar into the maxillary sinus after a severe trauma: a case report.  

PubMed

Dental injuries are common following facial trauma. This article presents a rare injury: the dislocation of a third molar into the maxillary sinus after complex mandibular and maxillary tuberosity fractures. The possible mechanism and clinical treatment are discussed. PMID:17511841

Cai, Heng-Xing; Long, Xing; Cheng, Yong; Li, Xiao-Dan; Jin, Hui-Xi

2007-06-01

315

Molar Extinction Coefficients of Liquid O3F2, O2F2, and O3 in the Visible Range  

Microsoft Academic Search

The absorption spectra for solutions of liquid O3F2, O2F2, and O3 in a Freon mixture of CClF3 and CCl2F2, and that of liquid O3 in liquid O2 were measured at 77°K and their molar extinction coefficients calculated. The effect of temperature on the molar extinction coefficient of liquid O2F2 in the Freon mix was studied.

A. D. Kirshenbaum; A. G. Streng

1961-01-01

316

Considerations of mandibular angle fractures during and after surgery for removal of third molars: a review of the literature  

Microsoft Academic Search

Background  Angle fractures are quite common considering that the angle of the mandible forms an area of lower resistance which contains\\u000a a thicker upper border, a thin basilar bone, and the presence of an impacted mandibular third molar. Common complications\\u000a of mandibular third molar surgery include alveolar osteitis (dry socket), secondary infection, nerve dysfunction, and hemorrhage.\\u000a Reports of mandibular fracture during

Bruno Ramos Chrcanovic; Antônio Luís Neto Custódio

2010-01-01

317

Ionic Molar Conductivities in Solutions of KCl, NaCl and LiCl in Glycerol at 25°C  

Microsoft Academic Search

Conductivities of solutions of KCl, NaCl and LiCl in glycerol at 25°C have been measured for concentrations in the range 0.0005 to 0.5 mol dm, and values of molar conductivity at infinite dilution obtained by extrapolation. Using previously measured transference numbers for KCl dissolved in glycerol, values of ionic molar conductivities at infinite dilution have been deducted for K, Na,

M. C. Blanco; D. C. Champeney; M. Kameche

1989-01-01

318

Molar apicectomy with amalgam root-end filling: results of a prospective study in two district general hospitals  

Microsoft Academic Search

Aim To determine the five-year success rates, site or sites of failure, prognostic indicators and lower lip morbidity associated with molar apicectomy using amalgam root-end filling.Design Multicentre, prospective study.Setting The departments of oral and maxillo-facial surgery in two district general hospitals.Method One thousand and seven molar apicectomy procedures, combined with amalgam root-end filling were expedited during the period 1974–1995. A

T M Gale; C M Wesson

2003-01-01

319

Liquid-phase degradation of polyethylene wax over mordenite catalysts with different Si\\/Al molar ratios  

Microsoft Academic Search

The catalytic liquid-phase degradation of polyethylene wax into fuel oil was studied using mordenite catalysts with various Si\\/Al molar ratios prepared by dealumination. The total yield of gas and liquid products showed a volcano plot along the Si\\/Al molar ratio of mordenite. No significant change was observed in the composition of the liquid product for all catalysts used in this

Young San You; Jong-Seob Shim; Jong-Ho Kim; Gon Seo

1999-01-01

320

Excess molar volumes of diisopropylamine + (C 1–C 5) alkan-1-ols: Application of the ERAS model and cubic EOS  

Microsoft Academic Search

Densities of the binary mixtures consist of methanol, ethanol, 1-propanol, 1-butanol and 1-pentanol with diisopropylamine were measured at temperatures (293.15, 298.15, 303.15 and 313.15) K and atmospheric pressure. Data were used to calculate the excess molar volumes. All the excess molar volumes are large and negative over the whole range of mole fraction, indicating strong interactions between unlike molecules. The

Mohammad Almasi; Maryam Shojabakhtiar

2011-01-01

321

A computerised third molar surgery simulator--results of supervision by different professionals.  

PubMed

The purpose of the study was to investigate which supervisory approach afforded the most efficient learning method for undergraduate students in oral and maxillofacial surgery (OMS) using a computerised third molar surgery simulator. Fifth year dental students participated voluntarily in a randomised experimental study using the simulator. The amount of time required and the number of trials used by each student were evaluated as a measure of skills development. Students had the opportunity to practise the procedure until no further visible improvements were achieved. The study assessed four different types of supervision to guide the students. The first group was where they were supported by a teacher/specialist in OMS, the second by a teaching assistant, the third group practised without any supervision and the fourth received help from a simulator technician/engineer. A protocol describing assessment criteria was designed for this purpose, and a questionnaire was completed by all participating students after the study. The average number of attempts required to virtually remove a third molar tooth in the simulator was 1.44 times for the group supervised by an OMS teacher; 1.5 times for those supervised by a teaching assistant; 2.8 times for those who had no supervision; and 3.6 times when support was provided only by a simulator technician. The results showed that the most efficient experience of the students was when they were helped by an OMS teacher or a teaching assistant. In a time and cost-effective perspective, supervision by a teaching assistant for a third molar surgery simulator would be the optimal choice. PMID:24521173

Rosen, A; Eliassi, S; Fors, U; Sallnäs, E-L; Forsslund, J; Sejersen, R; Lund, B

2014-05-01

322

Modified cuspal relationships of mandibular molar teeth in children with Down's syndrome  

PubMed Central

A total of 50 permanent mandibular 1st molars of 26 children with Down's syndrome (DS) were examined from dental casts and 59 permanent mandibular 1st molars of normal children were examined from 33 individuals. The following measurements were performed on both right and left molars (teeth 46 and 36 respectively): (a) the intercusp distances (mb-db, mb-d, mb-dl, db-ml, db-d, db-dl, db-ml, d-dl, d-ml, dl-ml); (b) the db-mb-ml, mb-db-ml, mb-ml-db, d-mb-dl, mb-d-dl, mb-dl-d angles; (c) the area of the pentagon formed by connecting the cusp tips. All intercusp distances were significantly smaller in the DS group. Stepwise logistic regression, applied to all the intercusp distances, was used to design a multivariate probability model for DS and normals. A model based on 2 distances only, mb-dl and mb-db, proved sufficient to discriminate between the teeth of DS and the normal population. The model for tooth 36 for example was as follows: formula here A similar model for tooth 46 was also created, as well as a model which incorporated both teeth. With respect to the angles, significant differences between DS and normals were found in 3 out of the 6 angles which were measured: the d-mb-dl angle was smaller than in normals, the mb-d-dl angle was higher, and the mb-dl-d angle was smaller. The dl cusp was located closer to the centre of the tooth. The change in size occurs at an early stage, while the change in shape occurs in a later stage of tooth formation in the DS population.

PERETZ, BENJAMIN; SHAPIRA, JOSEPH; FARBSTEIN, HANNA; ARIELI, ELIAHU; SMITH, PATRICIA

1998-01-01

323

Orthodontic molar brackets: the effect of three different base designs on shear bond strength.  

PubMed

The purpose of the study was to assess the relative base designs of three different maxillary molar stainless steel brackets with reference to the shear bond strength of three different adhesive resins. The molar brackets used were Victory series (3M Unitek), Upper Molar (GAC) and Optimesh XRT (Ormco). The adhesives used were Transbond XT (3M Unitek), Enlight (Ormco) and Sure Ortho Light Bond (Sure Orthodontics). The human enamel specimens (144) were randomly divided into nine groups and each group (n=16) was allocated to a bracket/adhesive combination. The contact surface of each of the bracket bases was measured three dimensionally using a reflex microscope. The base designs were also subjected to further microscopic investigations. The brackets were bonded to the enamel, temperature cycled and the shear bond strength was measured. The size and design of each of the brackets was different. The base size, surface treatment, mesh strand diameter and aperture size of the bracket base mesh have a significant effect on the shear bond strength at the bracket/adhesive interface. The shear bond strengths of all three Ormco bracket/adhesive resin combinations (5.8-6.8 MPa) were significantly lower (p<0.05; Kruskal-Wallis) than the other six bracket/adhesive combinations (9.4-12.1 MPa). The different adhesive types (3 types) could not be mainly responsible for the low shear bond values found for the Ormco bracket. The 3M Unitek combination of the Victory series bracket and Transbond XT adhesive proved to have a high shear bond strength without enamel damage. PMID:23675217

Hudson, Athol P; Grobler, Sias R; Harris, Angela M P

2011-03-01

324

Iodination of Fab fragments: Effect of I/Fab molar ratio  

SciTech Connect

Radioisotopes of iodine covalently coupled to antibodies have formed the standard against which other radiolabeled antibody tracers are compared. Since the use of monoclonal antibodies (MoAb) for the diagnosis and therapy of malignant diseases is increasing rapidly the authors wished to investigate radiolabeling variables which affect the immunointegrity of radioiodinated antibodies. The authors studied the electrophilic (chloramine-T) iodination of the Fab fragment of a murine MoAb against the high molecular weight proteoglycan antigen of human melanoma. The immunoreactivity of the iodianted Fab was assessed using a cell binding assay with formaldehyde-fixed cells of a selected cell line (number 2669). The in vitro stability of the labeled fragment was studied electrophoretically. The results indicate that the reaction time and concentrations of chloramine-T were not critical within broad limits. On the other hand immunoreactivity and deiodination over time (shelf-life) were inversely related and very sensitive to I/Fab molar ratio even at concentrations below -0.1 atom of I per Fab molecule. This has important implications for the radiotherapy of malignant tumors using I-131 labeled immunoglobulins which often have higher I/Fab molar ratios (100 mCi I-131/10 mg Fab approx. = 0.5 I atoms/Fab) versus diagnostic preparations (10 mCi I-131/5 mg Fab approx. = 0.1 I atoms/Fab). Thus the authors conclude that to maintain high immunointegrity the I/Fab molar ratio should be kept low, especially for therapeutic preparations, by using correspondingly higher amounts of Fab.

Kishore, R.; Eary, J.F.; Beaumier, P.L.; Hellstrom, K.E.; Hellstrom, I.; Nelp, W.B.

1985-05-01

325

Orthodontic Molar Brackets: The Effect of Three Different Base Designs on Shear Bond Strength  

PubMed Central

The purpose of the study was to assess the relative base designs of three different maxillary molar stainless steel brackets with reference to the shear bond strength of three different adhesive resins. The molar brackets used were Victory series (3M Unitek), Upper Molar (GAC) and Optimesh XRT (Ormco). The adhesives used were Transbond XT (3M Unitek), Enlight (Ormco) and Sure Ortho Light Bond (Sure Orthodontics). The human enamel specimens (144) were randomly divided into nine groups and each group (n=16) was allocated to a bracket/adhesive combination. The contact surface of each of the bracket bases was measured three dimensionally using a reflex microscope. The base designs were also subjected to further microscopic investigations. The brackets were bonded to the enamel, temperature cycled and the shear bond strength was measured. The size and design of each of the brackets was different. The base size, surface treatment, mesh strand diameter and aperture size of the bracket base mesh have a significant effect on the shear bond strength at the bracket/adhesive interface. The shear bond strengths of all three Ormco bracket/adhesive resin combinations (5.8-6.8 MPa) were significantly lower (p<0.05; Kruskal-Wallis) than the other six bracket/adhesive combinations (9.4-12.1 MPa). The different adhesive types (3 types) could not be mainly responsible for the low shear bond values found for the Ormco bracket. The 3M Unitek combination of the Victory series bracket and Transbond XT adhesive proved to have a high shear bond strength without enamel damage.

Hudson, Athol P.; Grobler, Sias R.; Harris, Angela M. P.

2011-01-01

326

Effects of debridement with an ultrasonic furcation tip in degree II furcation involvement of mandibular molars.  

PubMed

The purpose of this study was to evaluate the clinical effects of closed debridement with an ultrasonic furcation tip in degree II furcation involvement of mandibular molars. Fifteen patients with degree II furcation involvement in mandibular first and/ or second molars participated in the study. All patients were given oral hygiene instruction. Plaque score, probing depth, probing attachment level and bleeding on probing were recorded at baseline, 1, 4, 8 and 12 weeks. Following a baseline examination, a single episode of supra- and subgingival debridement was provided using an ultrasonic furcation tip in the test group, and an ultrasonic conventional tip and hand scalers under local anesthesia in the control group. At baseline, the mean horizontal probing depth in the test group was 6.35 mm and in the control group 6.06 mm. These values decreased to 4.88 mm and 5.29 mm respectively after 12 weeks. There were horizontal probing attachment gains of 1.29 mm in the test group and 0.59 mm in the control group after 12 weeks (P < 0.01). The bleeding scores were 1.0 in the test group and 0.88 in control group at baseline. These scores were improved to 0.12 in the test group and 0.59 in the control group after 12 weeks (P < 0.01). The results suggest that ultrasonic debridement with a furcation tip has a significantly better potential in treating degree II furcation involvement of mandibular molars. PMID:12670094

Sugaya, Tsutomu; Kawanami, Masamitsu; Kato, Hiroshi

2002-10-01

327

Mineral Trioxide Aggregate vs. Calcium Hydroxide in Primary Molar Pulpotomy: A Systematic Review  

PubMed Central

Introduction: The aim of this quantitative systematic review/meta-analysis was to compare the treatment outcomes of mineral trioxide aggregate (MTA) and calcium hydroxide (CH) in pulpotomy of human primary molars. The focused PICO question was “in case of pulp exposure in vital primary molars, how does MTA pulpotomy compare to CH in terms of clinical/radiographic success?” Methods and Materials: We retrieved published randomized clinical trials (RCTs) of at least 6-month duration; our search included articles published up to March 2013 in five following databases: PubMed (Medline), Cochrane database of systematic reviews, Science Citation Index, EMBASE, and Google Scholar. Mantel Haenszel and Inverse Variance-weighted methods were applied by STATA; the relative risk (RR) was calculated with 95% confidence intervals (CI). Results: A total of 282 English articles were collected. Two authors independently screened the articles and five RCTs were selected; data extraction and quality assessment were then carried out. Four RCTs were appropriate for meta-analysis according to their follow-up times by Mantel Haenszel method. Statistically significant difference was found between success rate of MTA compared to CH, with RR=0.08 (95% CI, 0.02-0.39), RR=0.19 (95% CI, 0.08-0.46), and RR=0.38 (95% CI, 0.21-0.68) for 6-, 12-, and 24-month follow-ups, respectively. A significant difference was also observed for all included RCTs after analyses using the Inverse Variance-weighted method (RR=0.44; 95% CI, 0.27-0.72). Conclusions: Systematic review/meta-analysis of included RCTs revealed that for pulpotomy of vital primary molars, MTA has better treatment outcomes compared to CH.

Shirvani, Armin; Hassanizadeh, Raheleh; Asgary, Saeed

2014-01-01

328

Effect of unilateral extraction of molar teeth on suprahyoid muscles: macroscopic and ultrastructural aspects.  

PubMed

Anatomical and physiologic components are parts of the stomatognathic system and their interaction results in integrated functional activities. Important alterations in the masticatory system originated by dental loss affect the bone, oral mucosa and muscular function. Dental arch structures specifically designed to receive and expose teeth allow performance of their functions. But the distinction between bony and soft tissues is lost when teeth are removed since there is not a specific function to be completed. The aim of this study was to evaluate the macroscopic and ultrastructural effects of the unilateral extraction of molar teeth on the suprahyoid muscles function, using twenty young male gerbils (Meriones unguiculatus) as the experimental animal model. They were divided in experimental malocclusion (n=10) and control (n=10) groups. The experimental malocclusion group was submitted to exodontia of the left upper molars and the control group was not submitted to this procedure and served as sham-operated. For macroscopic analysis of the suprahyoid muscle, the skin was uplifted and the muscles dissected individually and removed for weight analysis according to Scherle method. The electron microscopy analysis was made in ultra thin sections of small suprahyoid muscle fragments from the experimental and control groups, examined in a Jeol 1010, 880 Kv transmission electron microscope. Several micrographs at magnifications of 3000x, 6000x, 30,000x were randomly selected for the qualitative analysis of the muscle fiber ultrastructures. Sixty days after the induced unilateral occlusal alteration no macroscopic morphologic changes was detected in the suprahyoid muscles and the muscle volume differences between the right and left sides and between groups were not significant. However, in the ultrastructural analysis suprahyoid muscles showed characteristics of specific adaptation to the unilateral occlusal alteration, by the reduced density of subsarcolemmal mitochondria and the shorter and less numerous ramifications in intermyofibrilar mitochondria localized between electronlucid myofibrils. It is concluded that unilateral exodontia of all the upper left molars affect the ultrastructural morphology of suprahyoid muscle fibers. PMID:18693023

Iyomasa, Mamie Mizusaki; Issa, João Paulo Mardegan; Siéssere, Selma; Regalo, Simone Cecílio Hallak; Watanabe, Ii-sei

2008-12-01

329

Influence of Different Apical Preparations on Root Canal Cleanliness in Human Molars: a SEM Study  

PubMed Central

ABSTRACT Objectives To compare the influence of type and dimensions of the apical preparation on the cleanliness of the apical area in molars. Material and Methods A total of 120 root canals (MB and DB root canals from 30 maxillary molars and mesial root canals from 30 mandibular molars) were instrumented with Mtwo NiTi rotary instruments to a size 25/0.06 taper and were equally divided into three different experimental groups depending on the subsequently apical root canal preparation: Group 1: no further apical preparation, Group 2: apical preparation with Mtwo files to a size 40/0.04 taper, Group 3: apical preparation with Mtwo Apical Files. All root canals were observed through scanning electron microscopy (SEM). Presence of superficial debris and smear layer was evaluated using a score system. Data were statistically analysed using the Kruskal-Wallis and Bonferroni tests with a level of significance set at P < 0.05. Results Kruskal-Wallis test revealed no differences among groups in the middle and coronal third (P > 0.05), while at the apical level, there was a significant difference for both residual debris and presence of smear layer between Group 1 and both Group 2 (P = 0.003 and P = 0.014) and 3 (P = 0.012 and P = 0.021), while no difference was present between Group 2 and Group 3 (P = 0.871 and P = 0.923). Conclusions Cleanliness of the apical third in terms of debris and smear layer was statistically better when an apical preparation was performed to a size 40/0.04 taper or with the use of the Mtwo Apical Files.

Grande, Nicola M.; Tocci, Luigi; Testarelli, Luca; Gambarini, Gianluca

2014-01-01

330

Construction of a cDNA library for miniature pig mandibular deciduous molars  

PubMed Central

Background The miniature pig provides an excellent experimental model for tooth morphogenesis because its diphyodont and heterodont dentition resembles that of humans. However, little information is available on the process of tooth development or the exact molecular mechanisms controlling tooth development in miniature pigs or humans. Thus, the analysis of gene expression related to each stage of tooth development is very important. Results In our study, after serial sections were made, the development of the crown of the miniature pigs’ mandibular deciduous molar could be divided into five main phases: dental lamina stage (E33-E35), bud stage (E35-E40), cap stage (E40-E50), early bell stage (E50-E60), and late bell stage (E60-E65). Total RNA was isolated from the tooth germ of miniature pig embryos at E35, E45, E50, and E60, and a cDNA library was constructed. Then, we identified cDNA sequences on a large scale screen for cDNA profiles in the developing mandibular deciduous molars (E35, E45, E50, and E60) of miniature pigs using Illumina Solexa deep sequencing. Microarray assay was used to detect the expression of genes. Lastly, through Unigene sequence analysis and cDNA expression pattern analysis at E45 and E60, we found that 12 up-regulated and 15 down-regulated genes during the four periods are highly conserved genes homologous with known Homo sapiens genes. Furthermore, there were 6 down-regulated and 2 up-regulated genes in the miniature pig that were highly homologous to Homo sapiens genes compared with those in the mouse. Conclusion Our results not only identify the specific transcriptome and cDNA profile in developing mandibular deciduous molars of the miniature pig, but also provide useful information for investigating the molecular mechanism of tooth development in the miniature pig.

2014-01-01

331

Inactivation of Tgfbr2 in Osterix-Cre expressing dental mesenchyme disrupts molar root formation.  

PubMed

It has been difficult to examine the role of TGF-ß in post-natal tooth development due to perinatal lethality in many of the signaling deficient mouse models. To address the role of Tgfbr2 in postnatal tooth development, we generated a mouse in which Tgfbr2 was deleted in odontoblast- and bone-producing mesenchyme. Osx-Cre;Tgfbr2(fl/fl) mice were generated (Tgfbr2(cko)) and post-natal tooth development was compared in Tgfbr2(cko) and control littermates. X-ray and ?CT analysis showed that in Tgfbr2(cko) mice radicular dentin matrix density was reduced in the molars. Molar shape was abnormal and molar eruption was delayed in the mutant mice. Most significantly, defects in root formation, including failure of the root to elongate, were observed by postnatal day 10. Immunostaining for Keratin-14 (K14) was used to delineate Hertwig's epithelial root sheath (HERS). The results showed a delay in elongation and disorganization of the HERS in Tgfbr2(cko) mice. In addition, the HERS was maintained and the break up into epithelial rests was attenuated suggesting that Tgfbr2 acts on dental mesenchyme to indirectly regulate the formation and maintenance of the HERS. Altered odontoblast organization and reduced Dspp expression indicated that odontoblast differentiation was disrupted in the mutant mice likely contributing to the defect in root formation. Nevertheless, expression of Nfic, a key mesenchymal regulator of root development, was similar in Tgfbr2(cko) mice and controls. The number of osteoclasts in the bone surrounding the tooth was reduced and osteoblast differentiation was disrupted likely contributing to both root and eruption defects. We conclude that Tgfbr2 in dental mesenchyme and bone is required for tooth development particularly root formation. PMID:23933490

Wang, Ying; Cox, Megan K; Coricor, George; MacDougall, Mary; Serra, Rosa

2013-10-01

332

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

333

Mandibular Second Molar with a Single Root and a Single Canal: Case Series  

PubMed Central

The variability of root canal system morphology of multirooted teeth represents a continuous challenge to endodontic diagnosis and therapeutics. This report extends the range of known possible anatomical variations to include teeth with lesser number of root and root canals. Variations of root canal systems need not always be in the form of extra canals. Clinicians should be aware that there is a possibility of existence of fewer number of roots and root canals than the normal root canal anatomy. Thus the aim of this article is to present three cases of endodontically managed mandibular second molars with a single root and root canal.

Roy, Anna; Velmurugan, Natanasabapathy; Suresh, Nandhini

2013-01-01

334

A novel technique for removal of broken instrument from root canal in mandibular second molar.  

PubMed

The fracture of an endodontic instrument is an obstacle in completion of a routine successful pulp space therapy. Ni-Ti instruments corrode when in contact with sodium hypochlorite which leads to their deterioration and ultimately fracture during use. Removal of separated instrument from root canal is often a very difficult procedure. This procedure is more complicated when the instrument separated is closer to the mandibular canal. A case is presented in which a separated hand instrument was retrieved from the mesio buccal of a second molar approximating the mandibular canal root by replantation. PMID:24748311

Shenoy, Amarnath; Mandava, Pragna; Bolla, Nagesh; Vemuri, Sayish

2014-01-01

335

Efficient sensitization of nanocrystalline TiO 2 films with high molar extinction coefficient ruthenium complex  

Microsoft Academic Search

A novel heteroleptic polypyridine ruthenium complex, cis-Ru(L1)(L2)(NCS)2, L1=4,4?-dicarboxylic acid-2,2?-bipyridine (dcbpy), L2=4,4?-bis[p-diethylamino]-?-styryl]-2,2?-bipyridine, was synthesized. The dye displays extremely high molar extinction coefficient, which is comparable with organic dye. Preliminary test shows the dye-sensitized TiO2 solar cell gives high conversion efficiency up to 8.65% under 1 Sun, while 8.35% is given for N3 based DSCs under the same condition. The dye will

Ke-Jian Jiang; Jiang-bin Xia; Naruhiko Masaki; Shuji Noda; Shozo Yanagida

2008-01-01

336

Synthesis and photoelectrochemical characterization of a high molar extinction coefficient heteroleptic ruthenium(II) complex  

Microsoft Academic Search

A new high molar extinction coefficient heteroleptic ruthenium(II) complex (m-BL-1) that contains a 4,4’4”-tricaboxy-2,2’:6’,2”-terpyridine, 4,4’-bis-[3,5-di-tert-butyl-phenyl)-vinyl]-[2,2’]bipyridyl and a thiocyanate ligand in its molecular structure has been synthesized and completely\\u000a characterized by CHN, Mass, 1H-NMR, UV-Vis, and fluorescence spectroscopies as well as cyclic voltammetry. The new sensitizer was tested in dye-sensitized\\u000a solar cells using three different redox electrolytes and compared its performance

L GIRIBABU; VARUN KUMAR SINGH; M SRINIVASU; CH VIJAY KUMAR; V GOPAL REDDY; Y SOUJNYA; P YELLA REDDY

337

Molar Volume Dependence of Static Magnetization and Ordering Temperature in bcc Solid 3He  

NASA Astrophysics Data System (ADS)

Nuclear magnetic ordering in bcc 3He has been studied by a static magnetization measurement from 10 down to 0.3 mK for a molar volume region of V=24.14 to V=22.46 cm3/mole. The results show that the ordering temperature TN varies in proportion to V16.5+/-1 and that the magnetization in the ordered state is constant. The magnetization reduced by its maximum value is found to be represented by a universal function of the reduced temperature TTN.

Hata, T.; Yamasaki, S.; Taneda, M.; Kodama, T.; Shigi, T.

1983-10-01

338

Molar mass, surface tension, and droplet growth kinetics of marine organics from measurements of CCN activity  

NASA Astrophysics Data System (ADS)

The CCN-relevant properties and droplet growth kinetics are determined for marine organic matter isolated from seawater collected near the Georgia coast. The organic matter is substantially less CCN active than (NH4)2SO4, but droplet growth kinetics are similar. Köhler Theory Analysis (KTA) is used to determine the average organic molar masses of two samples, which are 4370 +/- 24% and 4340 +/- 18% kg kmol-1. KTA is used to infer surface tension depression, which is in excellent agreement with direct measurements. For the first time it is shown that direct measurements of surface tension are relevant for CCN activation, and this study highlights the power of KTA.

Moore, R. H.; Ingall, E. D.; Sorooshian, A.; Nenes, A.

2008-04-01

339

Prediction of excess molar volumes of binary mixtures of organic compounds from refractive indices  

Microsoft Academic Search

The excess molar volumes of 51 binary mixtures containing diverse groups of organic compounds: alcohols (methanol, ethanol,\\u000a propan-1-ol, butan-1-ol, pentan-1-ol, hexan-1-ol, and heptan-1-ol), (cyclo-) alkanes (hexane, heptane, octane, nonane, decane,\\u000a undecane, dodecane, and cyclohexane), esters (diethyl carbonate and ethyl chloroacetate), aromatics (o-xylene, m-xylene, p-xylene, and ethylbenzene), ketones (acetone), and ethers (anisole), were predicted from the refractive index data, using\\u000a three

Ivona R. Radovi?; Mirjana Lj. Kijev?anin; Marijan Z. Gabrijel; Slobodan P. Šerbanovi?; Bojan D. Djordjevi?

2008-01-01

340

Molar microwear in Praeanthropus afarensis: evidence for dietary stasis through time and under diverse paleoecological conditions.  

PubMed

Molar microwear fabrics in extant mammals vary with diet and, more particularly, the physical properties of the items that are consumed. Praeanthropus afarensis is well represented in the fossil record over a prolonged and radiometrically controlled temporal span, and reasonably robust paleoecological reconstructions are available for the various localities from which it is known. We therefore examined molar microwear in this species to determine whether diet varied in relation to time or in response to different ecological conditions. Of more than 70 specimens of Pr. afarensis that contain one or more worn permanent molars, only 19 were found to be suitable for microwear analysis. These derive from eight temporal horizons in the Laetolil Beds and Hadar Formation spanning approximately 400kyr (3.6-3.2Ma). Six paleoecological categories have been reconstructed for these horizons, and these were ranked on the basis of floral cover. None of the microwear variables observed for Pr. afarensis is significantly associated with either temporal or paleoecological rank. Thus, microwear and, by extension, diet does not appear to have altered significantly in Pr. afarensis through time or in response to different paleoecological circumstances. The wear pattern that appears to have characterized Pr. afarensis overlaps extensively that of Gorilla gorilla beringei and differs notably from the fabrics of extant primates (e.g., Cebus apella and Cercocebus albigena) that consume hard objects. The high proportion of scratches on Pr. afarensis molars suggests the inclusion of fine abrasives in or on the food items consumed by those individuals sampled in this study. Although Pr. afarensis may have been morphologically equipped to process hard, brittle items, the microwear data suggest that it did not necessarily do so, even in the face of varying environmental circumstances. Explanatory scenarios that describe Pr. afarensis as part of an evolutionary trajectory involving a more heavily masticated diet with an increased reliance on hard, brittle items need to be reconsidered. However, fallback foods that were consumed during relatively short, albeit critical periods may have exerted sufficient selective pressure to explain the evolution of the comparatively robust Pr. afarensis trophic apparatus. Because it is unlikely that many individuals from such restricted temporal intervals would be sampled in the paleontological record, we suggest that the most productive approach to the elucidation of paleodiet is the integration of genetic (morphological) and epigenetic (microwear and isotopic) lines of evidence. PMID:16750841

Grine, Frederick E; Ungar, Peter S; Teaford, Mark F; El-Zaatari, Sireen

2006-09-01

341

Mandibular second molar with a single root and a single canal: case series.  

PubMed

The variability of root canal system morphology of multirooted teeth represents a continuous challenge to endodontic diagnosis and therapeutics. This report extends the range of known possible anatomical variations to include teeth with lesser number of root and root canals. Variations of root canal systems need not always be in the form of extra canals. Clinicians should be aware that there is a possibility of existence of fewer number of roots and root canals than the normal root canal anatomy. Thus the aim of this article is to present three cases of endodontically managed mandibular second molars with a single root and root canal. PMID:24392427

Roy, Anna; Velmurugan, Natanasabapathy; Suresh, Nandhini

2013-11-01

342

Is there justification for prophylactic extraction of third molars? A systematic review.  

PubMed

The present systematic review was performed to investigate if there is evidence justifying the prophylactic extraction of third molars, one of the most frequent procedures in oral surgery. A series of searches was carried out for randomized, clinical trials and systematic reviews in seven databases (MEDLINE, BBO, LILACS, Web of Science, EMBASE, BIREME and Cochrane Library), with no restrictions regarding year or language. A supplemental manual search of the references of retrieved articles was also performed. The search strategy resulted in 260 papers. Both the data extracted and the quality of each paper were evaluated independently by two reviewers. After selection based on the preestablished eligibility criteria, four papers qualified for the final analysis. A medium degree of quality and methodological consistency was found in three studies, and low quality was found in one study. No studies showed a high degree of consistency. The most significant flaw was an inadequate sample size. The results of the present review indicate a lack of scientific evidence to justify the indication of the prophylactic extraction of third molars. PMID:23538430

Costa, Moacir Guilherme da; Pazzini, Camila Alessandra; Pantuzo, Mariele Cristina Garcia; Jorge, Maria Letícia Ramos; Marques, Leandro Silva

2013-01-01

343

Subjective values of different treatments for missing molars in older Japanese.  

PubMed

The purpose of this study was to determine how elderly Japanese people subjectively value treatment options for missing molars. Subjects were 528 independently community-dwelling elderly people. They were presented with photographs and descriptions of the process and expected outcomes of five possible treatment options: cantilever fixed dental prosthesis (FDP); resin or metal removable partial denture prosthesis (RPDP); implant-supported fixed prosthesis; and no replacement (shortened dental arch: SDA) for missing lower bilateral first and second molars. The participants filled in the questionnaire on subjective importance for treatment and indicated on a visual analogue scale how they valued the treatment (utility value: UV). Values were analysed by Mann-Whitney U-tests and multiple logistic regression analyses. Overall, the UVs for the FDP and the metal RPDP were the highest, and the UV for the SDA was the lowest. With respect to subjective importance, 'chewing ability' and 'no pain during function' were significantly selected more frequently. Multiple logistic regression analyses showed that the UV for the resin RPDP had significant positive associations with denture wearers and low treatment cost, whereas the implant had significant negative associations with denture wearers and older age. The SDA had significant positive associations with men and low treatment cost and a negative association with appearance. In conclusion, these elderly Japanese preferred cantilever FDPs and metal RPDPs to implants and 'no replacement.' It suggests that the SDA as an oral health goal can be questionable from the patients' point of view, even if it is biologically correct. PMID:20633073

Ikebe, K; Hazeyama, T; Kagawa, R; Matsuda, K; Maeda, Y

2010-12-01

344

Expression of amelogenin mRNA sequences during development of rat molars.  

PubMed

The expression of amelogenin mRNA in growing rat molars was studied. Northern blotting and the analysis of cDNA isolates revealed two predoninant variants. One group of cDNA inserts contained sequences of a long mRNA version and the other group contained mRNA sequences of the shorter leucin-rich amelogenin polypeptide (LRAP). The LRAP group was deficient in an internal stretch which coded for a peptide with a high potential for beta turns. Northern blot experiments showed that most amelogenin RNA in rat teeth was represented by two bands of 1.1 and 0.8 kb. Two oligonucleotide probes were designed that were specific for the long version and for the LRAP variant. The probes were used for in situ hybridization experiments on sections of developing maxillar teeth of rats between day 2 and day 15 after birth. Both RNA species were accumulated concomitantly and exclusively in cells of the inner enamel epithelium. Expression was first observed at the mesial cusp sides and finally involved the whole ameloblast layer except for the cells adjacent to the enamel-free region at the tip of the cusps. The early amelogenin RNA expression occurred adjacent to the initial deposition of the dentin matrix. Low amounts of amelogenin RNA persisted after the differentiation of ameloblasts into the maturative stage. The sequence of events was similar in all three molars. PMID:8770705

Wurtz, T; Lundmark, C; Christersson, C; Bawden, J W; Slaby, I; Hammarström, L

1996-01-01

345

The Effect of Prism Orientation in the Indentation Testing of Human Molar Enamel  

PubMed Central

Recent nanoindentation studies have demonstrated that the hardness and Young's modulus of human molar enamel decreases by more than 50% on moving from the occlusal surface to the dentin-enamel junction on cross-sectional samples. Possible sources of these variations are changes in local chemistry, microstructure, and prism orientation. This study investigates the latter source by performing nanoindentation tests at two different orientations relative to the hydroxyapatite prisms: parallel and perpendicular. A single sample volume was tested in order to maintain a constant chemistry and microstructure. The resulting data show very small differences between the two orientations for both hardness and Young's modulus. The 1.5 to 3.0% difference is significantly less than the standard deviations found within the data set. Thus, the variations in hardness and Young's modulus on cross-sectional samples of human molar are attributed to changes in local chemistry (varying levels of mineralization, organic matter, and water content) and changes in microstructure (varying volume fractions of inorganic crystals and organic matrix). The impact of prism orientation on mechanical properties measured by nanoindentation appears to be minimal.

Braly, A.; Darnell, L.A.; Mann, A.B.; Teaford, M.F.; Weihs, T.P.

2007-01-01

346

Enhanced molar sorption ratio for naphthalene through the impregnation of surfactant into chitosan hydrogel beads.  

PubMed

Surfactants in their impregnated forms in chitosan beads (CBs) were used for sorption of naphthalene (NAP) from aqueous solutions. Three different surfactants, Triton X-100 (TX100), cetyltrimethyl ammonium bromide (CTAB) and sodium dodecyl sulfate (SDS), were selected for this study. The results showed that surfactant-impregnated CS beads (SICBs) in the form of a separate phase surfactant were very effective for NAP sorption. The calculated molar sorption ratio (MSR(B) mol NAP/mol surfactant) of the surfactant impregnated into SICBs was much greater than the intrinsic molar solubilization ratio (MSR) in liquid phase. The high MSR(B) value could be explained by favorable configurations of surfactants in beads, such as micelles in sorbed form. The equilibrium isotherm did not follow Langmuir or Freundlich models, but followed Chapman sigmoidal equation, indicating co-operative sorption of solutes. Using SICBs as a separate phase surfactant may be a valuable tool for remediation of groundwater contaminated with hydrophobic organic compounds. PMID:20185302

Chatterjee, Sudipta; Lee, Dae S; Lee, Min W; Woo, Seung H

2010-06-01

347

A data-based study on survival of permanent molar restorations in adolescents.  

PubMed

Abstract Objective. The aim of this epidemiological, data-based survival study was to study the longevity of restorations in permanent molars of adolescents in the 1990 and 1995 birth cohorts during the period of 1992-2005 in the City of Vantaa, Finland. Materials and methods. The dental records of 2975 (1990 cohort) and 3147 (the 1995 cohort) adolescents were analyzed. The longevity of restorations from their placement until replacement was illustrated using the Kaplan-Meier survival curves. The influence of the cohort, gender and caries risk on the survival rate was assessed using the Cox proportional hazards regression analysis. Results. A majority of the restorations were tooth-colored. The proportion of amalgam restorations was almost non-existent in both cohorts. The survival of tooth-colored restorations on the occlusal surfaces of molars was lower in the 1995 cohort compared to the 1990 cohort. The need of replacement of glass-ionomer restorations was twice that of composite restorations' hazard ratio 2.27 (1.62-3.16). Conclusions. Composites are the most frequently used dental materials and have the longest survival times among adolescents. The survival of restorations per se is poorer in the more recent than in the earlier birth cohort. PMID:24070039

Vähänikkilä, Hannu; Käkilehto, Taina; Pihlaja, Joanna; Päkkilä, Jari; Tjäderhane, Leo; Suni, Jorma; Salo, Sinikka; Anttonen, Vuokko

2014-07-01

348

A Comparison of four pulpotomy techniques in primary molars: a long-term follow-up.  

PubMed

The study evaluated the effects of formocresol (FC), ferric sulphate (FS), calcium hydroxide (Ca[OH](2)), and mineral trioxide aggregate (MTA) as pulp dressing agents in pulpotomized primary molars. Sixteen children each with at least four primary molars requiring pulpotomy were selected. Eighty selected teeth were divided into four groups and treated with one of the pulpotomy agent. The children were recalled for clinical and radiographic examination every 6 months during 2 years of follow-up. Eleven children with 56 teeth arrived for clinical and radiographic follow-up evaluation at 24 months. The follow-up evaluations revealed that the success rate was 76.9% for FC, 73.3% for FS, 46.1% for Ca(OH)(2), and 66.6% for MTA. In conclusion, Ca(OH)(2)is less appropriate for primary teeth pulpotomies than the other pulpotomy agents. FC and FS appeared to be superior to the other agents. However, there was no statistically significant difference between the groups. PMID:18634926

Sonmez, Deniz; Sari, Saziye; Cetinba?, Tu?ba

2008-08-01

349

The apparent molar heat capacity of aqueous hydrochloric acid from 10 to 140/sup 0/C  

SciTech Connect

The apparent molar heat capacity of aqueous HCl has been measured at temperatures of 25, 76, 103, 125 and 140 C and molalities from 0.1 to 1.02 mol-kg/sup -1/ using a Picker flow microcalorimeter. The results were analyzed using the Pitzer and the Helgeson-Kirkhan-Flowers models to derive standard state heat capacities. The fitted parameters were also used to extrapolate the standard EMF of the silver-silver chloride reference electrode at steam saturation from 0 to 200 C and the mean ionic activity coefficient at 225 C, with an accuracy at the highest temperature of 2 MeV and 4%, respectively. The results confirm that experimental values of the apparent molar heat capacity to just over 100 C can be used to extrapolate standard state and excess Gibbs energies above 250 C, when the corresponding enthalpies at 25 C are accurately known. This work was carried out owing to the importance of HCl as a reference solute for measuring and tabulating the thermodynamic properties of electrolyte solutions at the elevated temperatures and pressures encountered in in situ bitumen recovery operations, steam generators and natural geothermal systems.

Tremaine, P.R.; Barbero, J.A.; Sway, K.

1986-01-01

350

A correlation study of occlusal and pulp chamber anatomy: the mandibular first molar.  

PubMed

Many parameters must be addressed for endodontic therapy to succeed. Because conservation of tooth structure is vital, the pulp chamber and root canal orifices should be located by using a method that is consistent yet accurate. The correlation of occlusal anatomy with the locations of the root canal orifice may aid dentists with access design. This study sought to determine if a correlation existed between occlusal surface anatomy, pulp chamber location, and root canal orifice location. This in vitro study utilized 21 human mandibular first molars. For each specimen, amalgam restorations were placed in the respective cusp tips, with gutta-percha placed in each canal at the level of the furcation. The authors made digital radiographs and occlusal photographs of each complete specimen. The samples were sectioned horizontally at the level of the cementoenamel junction (CEJ). Using a digital software program, the radiographs were superimposed with the digital photographs and correlations of pulp chamber to locate the canal orifice and occlusal surface anatomy. The authors found that the pulp chamber of the mandibular first molar lies more lingual at the level of the CEJ. In addition, the orifices were consistent in their location relative to cusp tip anatomy, a discovery that may assist dentists with the access design. PMID:17511365

Mickel, Andre K; Chogle, Sami; Bingham, Robert; Self, McKinley; Bogle, John

2007-01-01

351

Identification of possible factors impacting dental students' ability to locate MB2 canals in maxillary molars.  

PubMed

This study examined the effect of the access size and straight-line path of access on third-year dental students' ability to locate a second mesiobuccal (MB2) canal in maxillary first and second molars. One hundred and six third-year dental students at one Faculty of Dentistry performed simulated root canal treatment with the aid of 2x magnification loupes on extracted teeth. A postgraduate endodontic student subsequently made a reasonable search for an untreated MB2 canal with the aid of a dental operating microscope. The mesiobuccal roots were then sectioned horizontally for determination of the canal configuration. The dental students were able to treat an MB2 canal in 15.8 percent of the teeth, but this was not associated with satisfactory access criteria. The postgraduate endodontic student identified an MB2 canal in 54.7 percent of the remaining tooth samples excluding those where the MB2 canal was found by the dental students; this represented 94.3 percent of those teeth confirmed by horizontal sectioning of the root to have an MB2 canal. The postgraduate student troughed, on average, 2.6 mm before negotiating the MB2 canal. As satisfactory access criteria and straight-line path of access did not correlate with the dental students' ability to find a second mesiobuccal canal, this result has important implications for educational goals with respect to endodontic treatment of maxillary molar teeth. PMID:24789839

Park, Ellen; Chehroudi, Babak; Coil, Jeffrey M

2014-05-01

352

The effects of informed consent format on preoperative anxiety in patients undergoing inferior third molar surgery  

PubMed Central

Objectives: To evaluate the effect of informed consent format on preoperative anxiety of patients. Material and Methods: We performed a prospective study (91 patients) undergoing lower third molar extraction. Patients were distributed into three groups. Informed consent for surgery was obtained through a written document, an oral interview or a video recording. Afterwards, patients were asked about their anxiety level and the effect the informed consent had had on it. Results: Whereas the information conveyed both in oral and written formats relieved the patient to some extent (in a scale of -3 to +3) 0.97±1.21 and 0.29±0.97, respectively), the video recording increased patient’s anxiety in a statistically significant way (in a scale of -3 to +3, -0.57±1.43). The difference obtained between the values obtained in oral and written information was not statistically significant. Discussion: The most adequate format, according to our study, would be the oral format. Key words:Anxiety, satisfaction, third molar surgery, Spielberger State-Trait Anxiety Inventory.

Heras-Meseguer, Marisa; Azcarate-Velazquez, Francisco; Hita-Iglesias, Pilar; Ruiz-de-Leon-Hernandez, Gonzalo; Hernandez-Pacheco, Esther; Gutierrez-Perez, Jose L.

2014-01-01

353

Refractive index, molar refraction and comparative refractive index study of propylene carbonate binary liquid mixtures.  

PubMed

Refractive indices (n) have been experimentally determined for the binary liquid-liquid mixtures of Propylene carbonate (PC) (1) with benzene, ethylbenzene, o-xylene and p-xylene (2) at 298.15, 303.15 and 308.15 K over the entire mole fraction range. The experimental values of n are utilised to calculate deviation in refractive index (?n), molar refraction (R) and deviation in molar refraction (?R). A comparative study of Arago-Biot (A-B), Newton (NW), Eyring and John (E-J) equations for determining refractive index of a liquid has been carried out to test their validity for all the binary mixtures over the entire composition range at 298.15 K. Comparison of various mixing relations is represented in terms of average deviation (AVD). The ?n and ?R values have been fitted to Redlich-Kister equation at 298.15 K and standard deviations have been calculated. The results are discussed in terms of intermolecular interactions present amongst the components. PMID:24061238

Wankhede, Dnyaneshwar Shamrao

2012-06-01

354

Health Technology Assessment of CEM Pulpotomy in Permanent Molars with Irreversible Pulpitis.  

PubMed

Introduction: Teeth with irreversible pulpitis usually undergo root canal therapy (RCT). This treatment modality is often considered disadvantageous as it removes vital pulp tissue and weakens the tooth structure. A relatively new concept has risen which suggests vital pulp therapy (VPT) for irreversible pulpitis. VPT with calcium enriched mixture (VPT/CEM) has demonstrated favorable treatment outcomes when treating permanent molars with irreversible pulpitis. This study aims to compare patient related factors, safety and organizational consideration as parts of health technology assessment (HTA) of the new VPT/CEM biotechnology when compared with RCT. Materials and Methods: Patient related factors were assessed by looking at short- and long-term clinical success; safety related factors were evaluated by a specialist committee and discussion board involved in formulating healthcare policies. Organizational evaluation was performed and the social implications were assessed by estimating the costs, availability, accessibility and acceptability. The impact of VPT/CEM biotechnology was assessed by investigating the incidence of irreversible pulpitis and the effect of this treatment on reducing the burden of disease. Results: VPT/CEM biotechnology was deemed feasible and acceptable like RCT; however, it was more successful, accessible, affordable, available and also safer than RCT. Conclusion: When considering socioeconomic implications on oral health status and oral health-related quality of life of VPT/CEM, the novel biotechnology can be more effective and more efficient than RCT in mature permanent molars with irreversible pulpitis. PMID:24396372

Yazdani, Shahram; Jadidfard, Mohammad-Pooyan; Tahani, Bahareh; Kazemian, Ali; Dianat, Omid; Alim Marvasti, Laleh

2014-01-01

355

The effect of prism orientation on the indentation testing of human molar enamel.  

PubMed

Recent nanoindentation studies have demonstrated that the hardness and Young's modulus of human molar enamel decreases by more than 50% on moving from the occlusal surface to the dentine-enamel junction on cross-sectional samples. Possible sources of these variations are changes in local chemistry, microstructure, and prism orientation. This study investigates the latter source by performing nanoindentation tests at two different orientations relative to the hydroxyapatite prisms: parallel and perpendicular. A single sample volume was tested in order to maintain a constant chemistry and microstructure. The resulting data show very small differences between the two orientations for both hardness and Young's modulus. The 1.5-3.0% difference is significantly less than the standard deviations found within the data set. Thus, the variations in hardness and Young's modulus on cross-sectional samples of human molar are attributed to changes in local chemistry (varying levels of mineralization, organic matter, and water content) and changes in microstructure (varying volume fractions of inorganic crystals and organic matrix). The impact of prism orientation on mechanical properties measured at this scale by nanoindentation appears to be minimal. PMID:17449008

Braly, A; Darnell, L A; Mann, A B; Teaford, M F; Weihs, T P

2007-09-01

356

Evaluation of formocresol, calcium hydroxide, ferric sulfate, and MTA primary molar pulpotomies  

PubMed Central

Objective: The aim of this study is to evaluate four different pulpotomy medicaments in primary molars. Materials and Methods: A total of 147 primary molars with deep caries were treated with four different pulpotomy medicaments (FC: formocresol, FS: ferric sulfate, CH: calcium hydroxide, and MTA: mineral trioxide aggregate) in this study. The criteria for tooth selection for inclusion were no clinical and radiographic evidence of pulp pathology. During 30 months of follow-up at 6-month intervals, clinical and radiographic success and failures were recorded. The differences between the groups were statistically analyzed using the Chi-square test and Kaplan-Meier analysis. Results: At 30 months, clinical success rates were 100%, 95.2%, 96.4%, and 85% in the FC, FS, MTA, and CH groups, respectively. In radiographic analysis, the MTA group had the highest (96.4%), and the CH group had the lowest success rate (85%). There were no clinical and radiographic differences between materials (P > 0.05). Conclusions: Although there were no differences between materials, only in the CH group did three teeth require extraction due to further clinical symptoms of radiographic failures during the 30-month follow-up period. None of the failed teeth in the other groups required extraction during the 30-month follow-up period.

Yildiz, Esma; Tosun, Gul

2014-01-01

357

The chronology of second molar development in Brazilians and its application to forensic age estimation  

PubMed Central

Purpose This study investigated the possible correlation between the mineralization of the second molars and the chronological age of a sample population of the state of Paraiba, Brazil. Materials and Methods One thousand eight hundred fifty-four digitized panoramic images using a scanner of a private dental radiology service were obtained in six months. Of these, 457 were selected from patients aged 4.6 to 16 years who met certain criteria. The images were assessed twice by a radiologist with 5 years experience. A minimum interval of 30 days between the evaluations of the same patient was established. To analyze the relationship between chronological age, calcification level proposed by Demirjian et al in 1973, gender, and tooth, a multiple linear regression model was adjusted, taking age as the response variable (p<0.05). Results The gender and calcification level were significantly correlated with the age of the patients (p<0.05). There was a significant difference between the average age of the patients' upper teeth compared to the lower ones in both genders (p<0.05). The dental development occurred earlier in female individuals than in male ones, and there was no significant difference between the right and left second permanent molars. Conclusion It was observed that ethnic variables are related to certain parameters of age and sex identification in the Brazilian population, providing important information for forensic evaluations.

Pontual, Andrea dos Anjos; Beltrao, Rejane Targino; Beltrao, Ricardo Villar; Pontual, Maria Luiza dos Anjos

2013-01-01

358

[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

359

Quadrupole terms in the Maxwell equations: Born energy, partial molar volume, and entropy of ions.  

PubMed

A new equation of state relating the macroscopic quadrupole moment density Q to the gradient of the field ?E in an isotropic fluid is derived: Q = ?Q(?E - U?·E/3), where the quadrupolarizability ?Q is proportional to the squared molecular quadrupole moment. Using this equation of state, a generalized expression for the Born energy of an ion dissolved in quadrupolar solvent is obtained. It turns out that the potential and the energy of a point charge in a quadrupolar medium are finite. From the obtained Born energy, the partial molar volume and the partial molar entropy of a dissolved ion follow. Both are compared to experimental data for a large number of simple ions in aqueous solutions. From the comparison the value of the quadrupolar length LQ is determined, LQ = (?Q/3?)(1/2) = 1-4 Å. Data for ion transfer from aqueous to polar oil solution are analyzed, which allowed for the determination of the quadrupolarizability of nitrobenzene. PMID:24559353

Slavchov, Radomir I; Ivanov, Tzanko I

2014-02-21

360

Quadrupole terms in the Maxwell equations: Born energy, partial molar volume, and entropy of ions  

NASA Astrophysics Data System (ADS)

A new equation of state relating the macroscopic quadrupole moment density seriesshape Q to the gradient of the field ?E in an isotropic fluid is derived: seriesshape Q = ?Q(?E - series U?·E/3), where the quadrupolarizability ?Q is proportional to the squared molecular quadrupole moment. Using this equation of state, a generalized expression for the Born energy of an ion dissolved in quadrupolar solvent is obtained. It turns out that the potential and the energy of a point charge in a quadrupolar medium are finite. From the obtained Born energy, the partial molar volume and the partial molar entropy of a dissolved ion follow. Both are compared to experimental data for a large number of simple ions in aqueous solutions. From the comparison the value of the quadrupolar length LQ is determined, LQ = (?Q/3?)1/2 = 1-4 Å. Data for ion transfer from aqueous to polar oil solution are analyzed, which allowed for the determination of the quadrupolarizability of nitrobenzene.

Slavchov, Radomir I.; Ivanov, Tzanko I.

2014-02-01

361

MOLAR: Modular Linux and Adaptive Runtime Support for HEC OS/R Research  

SciTech Connect

MOLAR is a multi-institution research effort that concentrates on adaptive, reliable,and efficient operating and runtime system solutions for ultra-scale high-end scientific computing on the next generation of supercomputers. This research addresses the challenges outlined by the FAST-OS - forum to address scalable technology for runtime and operating systems --- and HECRTF --- high-end computing revitalization task force --- activities by providing a modular Linux and adaptable runtime support for high-end computing operating and runtime systems. The MOLAR research has the following goals to address these issues. (1) Create a modular and configurable Linux system that allows customized changes based on the requirements of the applications, runtime systems, and cluster management software. (2) Build runtime systems that leverage the OS modularity and configurability to improve efficiency, reliability, scalability, ease-of-use, and provide support to legacy and promising programming models. (3) Advance computer reliability, availability and serviceability (RAS) management systems to work cooperatively with the OS/R to identify and preemptively resolve system issues. (4) Explore the use of advanced monitoring and adaptation to improve application performance and predictability of system interruptions. The overall goal of the research conducted at NCSU is to develop scalable algorithms for high-availability without single points of failure and without single points of control.

Frank Mueller

2009-02-05

362

Accuracy of Cameriere's cut-off value for third molar in assessing 18 years of age.  

PubMed

Due to increasingly numerous international migrations, estimating the age of unaccompanied minors is becoming of enormous significance for forensic professionals who are required to deliver expert opinions. The third molar tooth is one of the few anatomical sites available for estimating the age of individuals in late adolescence. This study verifies the accuracy of Cameriere's cut-off value of the third molar index (I3M) in assessing 18 years of age. For this purpose, a sample of orthopantomographs (OPTs) of 397 living subjects aged between 13 and 22 years (192 female and 205 male) was analyzed. Age distribution gradually decreases as I3M increases in both males and females. The results show that the sensitivity of the test was 86.6%, with a 95% confidence interval of (80.8%, 91.1%), and its specificity was 95.7%, with a 95% confidence interval of (92.1%, 98%). The proportion of correctly classified individuals was 91.4%. Estimated post-test probability, p was 95.6%, with a 95% confidence interval of (92%, 98%). Hence, the probability that a subject positive on the test (i.e., I3M<0.08) was 18 years of age or older was 95.6%. PMID:24365729

De Luca, S; Biagi, R; Begnoni, G; Farronato, G; Cingolani, M; Merelli, V; Ferrante, L; Cameriere, R

2014-02-01

363

Sealing versus partial caries removal in primary molars: a randomized clinical trial  

PubMed Central

Background The resin-based pit and fissure sealant is considered a successful tool in caries prevention, however there is a growing evidence of its use in controlling already established caries in posterior teeth. The aim of this clinical trial is to verify the efficacy of pit and fissure sealants in arresting dentinal caries lesions compared to partial excavation and restorative treatment in primary molar teeth. Methods Thirty six patients with occlusal cavitated primary molar reaching outer half of dentin were selected. The patients were randomly allocated into two groups: sealant application (experimental group – n?=?17) and restoration with composite resin (control group – n?=?19). Clinical and radiograph evaluation were performed after 6, 12 and 18 months. The chi-square test was used to verify the distribution of characteristics variables of the sample among the groups. The survival rate of treatments was evaluated using Kaplan–Meier survival and log-rank test. Fisher’s Exact and logistic regression tests were calculated in each evaluation period (??=?5%). Results The control group showed significantly better clinical survival after 18 months (p?=?0.0025). In both groups, no caries progression was registered on the radiographic evaluations. Conclusions Sealing had similar efficacy in the arrestment of caries progression of cavitated occlusal lesions compared to partial excavation of the lesions, even though the frequency of re-treatments was significantly higher in sealed lesions. Trial registration Registro Brasileiro de Ensaios Clínicos (ReBEC): RBR-9kkv53

2014-01-01

364

Bubble curves and saturated liquid molar volumes for chlorofluorohydrocarbon-hydrocarbon mixtures: Experimental data and modeling  

SciTech Connect

Vapor-liquid equilibria and liquid densities were obtained using a static apparatus fitted with a variable-volume cell which was described in detail by Valtz et al. (1). Results are given at four temperatures for the binary systems butane--1,2,2-trichlorotrifluoroethane, pentane--1,2-dichloro-1,1,2,2-tetrafluoroethane, hexane--1,2-dichloro-1,1,2,2-tetrafluoroethane, heptane--1,12-trichloro-1,2,2-trifluoromethane, heptane--1,2-dichloro-1,1,2,2-tetrafluoroethane, and benzene--1,2-dichloro-1,1,2,2-tetrafluoroethane and the ternary system 1,2-dichloro-1,1,2,2-tetrafluoroethane--1,1,2-trichloro-1,2,2-trifluoromethane--heptane. The best simultaneous representation of pressures and saturated liquid molar volumes at a given temperature and liquid composition for these mixtures is obtained using either the Patel-Teja or Trebble-Bishnoi-Salim equation of state (TBS EOS) in either their standard or generalized form (maximum deviation 0.7% in pressure and 3.1% in saturated liquid molar volume with the TBS EOS).

Laugier, S. (Ecole Nationale Superieure de Chimie et Physique de Bordeaux, Talence (France)); Richon, D.; Renon, H. (Ecole National Superieure des Mines de Paris, Fontainebleau (France). Lab. de Thermodynamique)

1994-01-01

365

Histopathologic evaluation of follicular tissues associated with impacted lower third molars  

PubMed Central

Context: Previous studies have reported that the dental follicular tissues associated with impacted lower third molars (ILTMs) may undergo cystic degeneration and/or neoplastic transformation. This is especially likely when the pericoronal space is >2.5 mm on intraoral radiographs and >3 mm on panoramic radiographs and to examine dental follicular tissue for pathological changes in patients with ILTMs and pericoronal radiolucencies of <2.5 mm. Aim: Histopathological evaluation of follicular tissues associated with ILTMs. Materials and Methods: The morphology of the hematoxylin and eosin-stained follicular tissues of 146 such impactions were studied. Results: On microscopy, no cystic structures with fibrous walls were identified. 85 cases (58%) showed fibrous or myxomatous connective tissue and no epithelial elements. 61 cases (42%) showed epithelial elements in addition to fibrocollagenous tissue. Of these, 16 cases exhibited epithelium, of which 13 cases showed reduced enamel epithelium and three cases showed squamous metaplasia/non-keratinized stratified squamous epithelium. Conclusions: All asymptomatic unerupted third molars with pericoronal radiolucency of <2.5 mm should be retained since they do not exhibit cyst formation microscopically.

Tegginamani, Anand S; Prasad, Rajendra

2013-01-01

366

Reliability of Third Molar Development for Age Estimation by Radiographic Examination (Demirjian's Method)  

PubMed Central

Introduction: Dental age estimation methods are of particular value because teeth are highly resistant to mechanical, chemical, or physical impacts and time. Teeth are the strongest parts in the human body and are therefore very resistant to external influences, such as extreme temperatures, explosions, and other extreme conditions, which make them available for extensive postmortem periods. Aim: To correlate chronological age with dental age using Demirijian’s method. Materials and Methods: The study was carried out on 100 digital orthopantamograms (OPG) of patients in the age group of 7 to 24 years. During the analysis, Magnify’ and Ruler’ tools were used. Mandibular right third molar was used for entire study. Data collected was analysed by using SPSS software. Results: Development of third molar in all stages was found slightly earlier in males than in females, when chronological age was compared with dental age using Demirjian method. 88% subject showed statistically significant linear correlation between chronological age and developmental age using Demirjian’s method. Conclusion: The linear correlation between chronological age and dental age using to Demirjian’s method was more in age group above 16 years and less in age group below 16 years. Demirijian’s method is a reliable guide for age estimation in age group of 7 to 24 years of age.

Patil, Swapnil N; Kamble, Seema D; Mowade, Tushar; Motghare, Pavan

2014-01-01

367

Molar position associated with a missing opposed and/or adjacent tooth: a follow up study in women.  

PubMed

The purpose of the study was to assess (i) the degree of overeruption of molars lacking opposed teeth and (ii) the inclination of molars with a mesial edentulous space and alsoto study (iii) changes during a 12 year period. The subject sample originated from the prospective population study of women in Gothenburg, Sweden where scanned panoramic radiographs taken with an interval of 12 years were analysed. Tipping as well as overeruption were scored on the two images according to a five-level scale. Sixty-seven subjects fulfilled the inclusion criteria at baseline and were referred to as "the non-extraction group". Further 35 subjects had lost the opposed and/or the adjacent tooth/teeth during the 12-year follow-up period: "the extraction-group". These groups were studied separately and a comparison between these groups was performed. The prevalence of molars tipped more than 15 degrees at baseline was 17.1% in the upper jaw and 44.3 % in the lower jaw, in the non-extraction group. At baseline overeruption was seen in 25 % of the unopposed upper molars and none of lower molars in the non-extraction group. The prevalence of tipping and overeruption was statistical significant less in the extraction group (P<0.01), than in the non-extraction group at baseline, but at follow-up no statistical significant group differences existed. In conclusion: The prevalence of tipped molars facing a mesial edentulous space and overerupted unopposed molars increased in adults during the 12-year period but the changes were small. Overeruption and tipping is most pronounced immediately after extractions. PMID:23957144

Lindskog-Stokland, Birgitta; Hakeberg, Magnus; Hansen, Ken

2013-01-01

368

Significance of radiological variables studied on orthopantamogram to pridict post-operative inferior alveoler nerve paresthesia after third molar extraction.  

PubMed

Context: Removal of impacted third molar is a procedure that is often associated with post-operative complications. The rate of complications is somewhat high because of its proximity to the vital structures. Inferior alveolar nerve paresthesia is one of the common complications of impacted their molar surgery. This is due to intimate relationship between roots of mandibular third molar and inferior alveolar canal. To access the proximity of inferior alveolar canal to third molar many diagnostic methods are suggested but in conventional radiography orthopantamogram is considered as the best. There are many findings onorthopantamogram that are suggestive of close proximity of nerve to the canal. In this study authors reviewed seven radiographic findings related to proximity of roots to the inferior alveolar nerve as seen on orthopantamogram and try to find a relationship between these radiographic variables and presence of post-operative paresthesia. Study Design: The study containd 100 impacted third molars need to be removed. Presence of radiographic findings on orthopantamogram were noted and analyzed, to find a relationship with occurrence of post-operative inferior alveolar nerve paresthesia. Materials and Methods: This study comprises of 100 impacted third molar teeth indicated for extraction. Cases were randomly selected from the patients, needs to undergo extraction of impacted mandibular third molar. After extraction cases were evaluated for occurrence of inferior alveolar nerve paresthesia. Stastical Analyisis: Data was transferred to SPss 21 software for frequency calculation, and two tailed p-values were obtained betweens these variables and post-operative paresthesia, by applying Fischer's exact test (GRAPH PAD SOFTWARE). Results: Out of seven, four radiological findings that are grooving of roots, hooked roots, bifid roots and obliteration of white line are significantly related to post-operative paresthesia while bending of canal, narrow canal and darkening of tooth roots over the canal are not significantly associated with post-operative morbidity of facial nerve. PMID:24995248

Pathak, Sachin; Mishra, Nitin; Rastogi, Madhur Kant; Sharma, Shalini

2014-05-01

369

The Component Slope Linear Model for Calculating Intensive Partial Molar Properties: Application to Waste Glasses and Aluminate Solutions - 13099  

SciTech Connect

Partial molar properties are the changes occurring when the fraction of one component is varied while the fractions of all other component mole fractions change proportionally. They have many practical and theoretical applications in chemical thermodynamics. Partial molar properties of chemical mixtures are difficult to measure because the component mole fractions must sum to one, so a change in fraction of one component must be offset with a change in one or more other components. Given that more than one component fraction is changing at a time, it is difficult to assign a change in measured response to a change in a single component. In this study, the Component Slope Linear Model (CSLM), a model previously published in the statistics literature, is shown to have coefficients that correspond to the intensive partial molar properties. If a measured property is plotted against the mole fraction of a component while keeping the proportions of all other components constant, the slope at any given point on a graph of this curve is the partial molar property for that constituent. Actually plotting this graph has been used to determine partial molar properties for many years. The CSLM directly includes this slope in a model that predicts properties as a function of the component mole fractions. This model is demonstrated by applying it to the constant pressure heat capacity data from the NaOHNaAl(OH){sub 4}-H{sub 2}O system, a system that simplifies Hanford nuclear waste. The partial molar properties of H{sub 2}O, NaOH, and NaAl(OH){sub 4} are determined. The equivalence of the CSLM and the graphical method is verified by comparing results determined by the two methods. The CSLM model has been previously used to predict the liquidus temperature of spinel crystals precipitated from Hanford waste glass. Those model coefficients are re-interpreted here as the partial molar spinel liquidus temperature of the glass components. (authors)

Reynolds, Jacob G. [Washington River Protection Solutions, LLC, P.O. Box 850, Richland, WA 99352 (United States)] [Washington River Protection Solutions, LLC, P.O. Box 850, Richland, WA 99352 (United States)

2013-07-01

370

Significance of Radiological Variables Studied on Orthopantamogram to Pridict Post-Operative Inferior Alveoler Nerve Paresthesia After Third Molar Extraction  

PubMed Central

Context: Removal of impacted third molar is a procedure that is often associated with post-operative complications. The rate of complications is somewhat high because of its proximity to the vital structures. Inferior alveolar nerve paresthesia is one of the common complications of impacted their molar surgery. This is due to intimate relationship between roots of mandibular third molar and inferior alveolar canal. To access the proximity of inferior alveolar canal to third molar many diagnostic methods are suggested but in conventional radiography orthopantamogram is considered as the best. There are many findings onorthopantamogram that are suggestive of close proximity of nerve to the canal. In this study authors reviewed seven radiographic findings related to proximity of roots to the inferior alveolar nerve as seen on orthopantamogram and try to find a relationship between these radiographic variables and presence of post-operative paresthesia. Study Design: The study containd 100 impacted third molars need to be removed. Presence of radiographic findings on orthopantamogram were noted and analyzed, to find a relationship with occurrence of post-operative inferior alveolar nerve paresthesia. Materials and Methods: This study comprises of 100 impacted third molar teeth indicated for extraction. Cases were randomly selected from the patients, needs to undergo extraction of impacted mandibular third molar. After extraction cases were evaluated for occurrence of inferior alveolar nerve paresthesia. Stastical Analyisis: Data was transferred to SPss 21 software for frequency calculation, and two tailed p-values were obtained betweens these variables and post-operative paresthesia, by applying Fischer’s exact test (GRAPH PAD SOFTWARE). Results: Out of seven, four radiological findings that are grooving of roots, hooked roots, bifid roots and obliteration of white line are significantly related to post-operative paresthesia while bending of canal, narrow canal and darkening of tooth roots over the canal are not significantly associated with post-operative morbidity of facial nerve.

Mishra, Nitin; Rastogi, Madhur Kant; Sharma, Shalini

2014-01-01

371

Accuracy of identifying juvenile/adult status from third molar development using prediction probabilities derived from logistic regression analysis.  

PubMed

The use of third molars in predicting juvenile/adult status (molar development was assessed using Köhler's grading on 268 orthopantomograms of Indian subjects. Logistic regression analysis was applied to determine allocation accuracy of juvenile/adult status and the level of probability that is "reliable" in predicting juvenile/adult status. Allocation accuracies ranged between 75.8% and 78.2% for the sexes combined, with minimal male-female differences. Adults were categorized more accurately than juveniles, suggesting that Köhler's grading puts Indian juveniles at greater risk of unwarranted punishment. In both sexes, juvenile/adult status was "reliably" predicted when the probability was >80% using individual third molars (excepting the lower right third molar in males); combining upper and lower third molars on the left/right sides, "reliable" predictions were possible when the probability was >80% and >90% for females and males, respectively. Overall, "reliable" juvenile/adult status prediction was achieved in c. 36% of subjects. PMID:24313875

Acharya, Ashith B; Bhowmik, Biyas; Naikmasur, Venkatesh G

2014-05-01

372

Prevalence of Impacted Molar Teeth among Saudi Population in Asir Region, Saudi Arabia - A Retrospective Study of 3 Years.  

PubMed

Aim: To report the prevalence of impacted third molars according to the age, gender and type among Saudi population. Materials and methods: This retrospective study involved 3800 panoramic radiographs of subjects aged 18 to 45 years who presented to the College of Dentistry, King Khalid University, Abha, Kingdom of Saudi Arabia for oral care during the period from February 2009 to February 2011. Data collected was entered into a spreadsheet (Excel 2000; Microsoft, US) and analyzed using Statistical Package for Social Sciences (SPSS) version 16.0. Results: A total of 713 impacted teeth were identified (18.76%) (p=0.003). The male to female ratio with impacted third molars was 604:109 (5.54:1) and the ratio of patients with impacted teeth was (5:1). Age group 1 (i.e., 20 to 25 years)had the highest prevalence of third molar tooth impaction (64.5%) and this decreased with increasing age. Conclusion: Incidence of tooth impaction is higher in the mandible than in maxilla. Males had a higher incidence of third molar impaction as compared to the females. Highest incidence is found in the age group of 20-25 years. Mesio-angular impaction was the most predominant type. How to cite this article: Syed KB, Kota Z, Ibrahim M, Bagi MA, Assiri MA. "Prevalence of Impacted Molar Teeth among Saudi Population in Asir Region, Saudi Arabia - A Retrospective Study of 3 Years". J Int Oral Health 2013; 5(1):43-47. PMID:24155577

Syed, Kamran Bokhari; Zaheer, Kamran Bokhari; Ibrahim, Mohammed; Bagi, Mustafa Abdel; Assiri, Mohammed Abdullah

2013-02-01

373

Prevalence of Impacted Molar Teeth among Saudi Population in Asir Region, Saudi Arabia - A Retrospective Study of 3 Years  

PubMed Central

Aim: To report the prevalence of impacted third molars according to the age, gender and type among Saudi population. Materials and methods: This retrospective study involved 3800 panoramic radiographs of subjects aged 18 to 45 years who presented to the College of Dentistry, King Khalid University, Abha, Kingdom of Saudi Arabia for oral care during the period from February 2009 to February 2011. Data collected was entered into a spreadsheet (Excel 2000; Microsoft, US) and analyzed using Statistical Package for Social Sciences (SPSS) version 16.0. Results: A total of 713 impacted teeth were identified (18.76%) (p=0.003). The male to female ratio with impacted third molars was 604:109 (5.54:1) and the ratio of patients with impacted teeth was (5:1). Age group 1 (i.e., 20 to 25 years)had the highest prevalence of third molar tooth impaction (64.5%) and this decreased with increasing age. Conclusion: Incidence of tooth impaction is higher in the mandible than in maxilla. Males had a higher incidence of third molar impaction as compared to the females. Highest incidence is found in the age group of 20-25 years. Mesio-angular impaction was the most predominant type. How to cite this article: Syed KB, Kota Z, Ibrahim M, Bagi MA, Assiri MA. "Prevalence of Impacted Molar Teeth among Saudi Population in Asir Region, Saudi Arabia – A Retrospective Study of 3 Years". J Int Oral Health 2013; 5(1):43-47.

Syed, Kamran Bokhari; Zaheer, Kamran Bokhari; Ibrahim, Mohammed; Bagi, Mustafa Abdel; Assiri, Mohammed Abdullah

2013-01-01

374

Selenium:mercury molar ratios in freshwater fish from Tennessee: individual, species, and geographical variations have implications for management.  

PubMed

Vertebrates, including humans, can experience adverse effects from mercury consumed in fish. Humans often prefer large predatory fish that bioaccumulate high mercury levels. Recent attention has focused on the role of selenium countering mercury toxicity, but there is little research on the selenium:mercury molar ratios in freshwater fish. We examine selenium:mercury molar ratios in freshwater fish from Tennessee at Poplar Creek which receives ongoing inputs of mercury from the Department of Energy's Oak Ridge Y-12 facility. Our objective was to determine variation of the ratios within species that might affect the protectiveness of selenium against mercury toxicity. Within species, the ratio was correlated significantly and positively with fish length only for two species. There was great individual variation in the selenium:mercury molar ratio within each species, except striped bass. The lack of a clear relationship between the selenium:mercury molar ratio and fish length, and the intraspecific variation, suggests that it would be difficult to use the molar ratio in predicting either the risk from mercury toxicity or in devising consumption advisories. PMID:22456727

Burger, Joanna; Gochfeld, Michael; Jeitner, C; Donio, M; Pittfield, T

2012-06-01

375

Correlation between crystallite size–optical gap energy and precursor molarities of ZnO thin films  

NASA Astrophysics Data System (ADS)

We investigated the structural and optical properties of ZnO thin films as an n-type semiconductor. The films were deposited at different precursor molarities using an ultrasonic spray method. In this paper we focused our attention on a new approach describing a correlation between the crystallite size and optical gap energy with the precursor molarity of ZnO thin films. The results show that the X-ray diffraction (XRD) spectra revealed a preferred orientation of the crystallites along the c-axis. The maximum value of the crystallite size of the films is 63.99 nm obtained at 0.1 M. The films deposited with 0.1 M show lower absorption within the visible wavelength region. The optical gap energy increased from 3.08 to 3.37 eV with increasing precursor molarity of 0.05 to 0.1 M. The correlation between the structural and optical properties with the precursor molarity suggests that the crystallite size of the films is predominantly influenced by the band gap energy and the precursor molarity. The measurement of the crystallite size by the model proposed is equal to the experimental data. The minimum error value was estimated by Eq. (4) in the higher crystallinity.

Benramache, S.; Belahssen, O.; Guettaf, A.; Arif, A.

2014-04-01

376

Differences in molar relationships and occlusal contact areas evaluated from the buccal and lingual aspects using 3-dimensional digital models  

PubMed Central

Objective The aims of this study were to use a 3-dimensional (3D) system to compare molar relationship assessments performed from the buccal and lingual aspects, and to measure differences in occlusal contact areas between Class II and Class I molar relationships. Methods Study casts (232 pairs from 232 subjects, yielding a total of 380 sides) were evaluated from both the buccal and lingual aspects, so that molar relationships could be classified according to the scheme devised by Liu and Melsen. Occlusal contact areas were quantified using 3D digital models, which were generated through surface scanning of the study casts. Results A cusp-to-central fossa relationship was observed from the lingual aspect in the majority of cases classified from the buccal aspect as Class I (89.6%) or mild Class II (86.7%). However, severe Class II cases had lingual cusp-to-mesial triangular fossa or marginal ridge relationships. Mean occlusal contact areas were similar in the Class I and mild Class II groups, while the severe Class II group had significantly lower values than either of the other 2 groups (p < 0.05). Conclusions Buccal and lingual assessments of molar relationships were not always consistent. Occlusal contact areas were lowest for the Class II-severe group, which seems to have the worst molar relationships - especially as seen from the lingual aspect.

Jang, Sook-Yoon; Kim, Minji

2012-01-01

377

Midbuccal canals of maxillary molars evaluated by cone-beam computed tomography: endodontic management of two cases.  

PubMed

Maxillary molars present variable root canal and root morphologies. This report describes the endodontic management of two cases of midbuccal canals found in maxillary molars. Midbuccal canals were present in a maxillary first molar with a single buccal root (Case 1), and in a maxillary second molar with three buccal roots (Case 2). An assessment of the internal configuration of these teeth was performed using cone-beam computed tomography (CBCT). Magnification with a dental operating microscope, surgical loupes, and the use of an endodontic explorer enabled the identification of the midbuccal canal orifices. The root canals in both cases were chemomechanically prepared and filled. Postobturation radiographic images revealed four (one midbuccal, two mesiobuccal and one palatal) and five (one midbuccal, two mesiobuccal, one distobuccal and one palatal) root canals, which were filled in Cases 1 and 2, respectively. Complex canal configurations of maxillary molars including the presence of midbuccal canals were presented. CBCT was a valuable tool in this diagnosis, as it provided a precise description of these unusual anatomical variations. PMID:24474352

Brito, Manoel; Moreira, Gil; Normanha, João Américo; Faria-e-Silva, André Luis; Camilo, Carla Cristina; Savioli, Ricardo Novak; Saquy, Paulo César

2013-01-01

378

Dilemmas pertaining to three canals in the mesiobuccal root of a maxillary second molar: a case report  

PubMed Central

The mesiobuccal root of the maxillary molars is well known to pose a hindrance during endodontic therapy. Presented here is a case of a maxillary left second molar where three canals were located in its mesiobuccal root with the use of visual and diagnostic aids. Difficulties encountered during the process of unveiling the tooth's internal anatomy were discussed. The dilemmas encountered pertained to the root canal configuration, the nomenclature of the extra canals, and the justification for the presence of a third canal. The root canal configuration of 3-2-1 was confirmed for the mesiobuccal root using information gained from clinical, radiographic, and multi-detector computed tomography (MDCT) scan findings. This case demonstrates the need for efforts to locate extra canals in the mesiobuccal root of the maxillary molars as their internal anatomy remains a mystery.

Acharya, Shashi Rashmi; Saraswathi, Muliya Vidya; Sharma, Padmaja; Ather, Amber

2013-01-01

379

Synthesis of aluminum nitride nanoparticles by a facile urea glass route and influence of urea/metal molar ratio  

NASA Astrophysics Data System (ADS)

Attention toward nanosized aluminum nitride (AlN) was rapidly increasing due to its physical and chemical characteristics. In this work, nanocrystalline AlN particles were prepared via a simple urea glass route. The effect of the urea/metal molar ratio on the crystal structure and morphology of nanocrystalline AlN particles was studied using X-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results revealed that the morphology and the crystal structure of AlN nanoparticles could be controlled by adjusting the urea/metal ratio. Furthermore, a mixture of Al2O3 and h-AlN was detected at the urea/metal molar ratio of 4 due to the inadequate urea content. With increasing the molar ratio, the pure h-AlN was obtained. In addition, the nucleation and growth mechanisms of AlN nanocrystalline were proposed.

Gao, Zhifang; Wan, Yizao; Xiong, Guangyao; Guo, Ruisong; Luo, Honglin

2013-09-01

380

Presence of Two Distal and One Mesial Root Canals in Mandibular Second Molars: Report of Four Cases  

PubMed Central

Most mandibular second molars have one and two canals in distal and mesial roots, respectively. This report represents four cases of mandibular second molars with a single mesial and two distal root canals with two different canal configurations. After access cavity preparation, two teeth had one distal and two mesial orifices, whereas in the two other teeth one mesial and two distal orifices were found. In the teeth with two mesial canal orifices, the distal root canal and one of root canals with a mesial orifice joined together in the apical part of the root, whereas in the two other teeth with one mesial and two distal canal orifices, three separate canals each with a different apical foramen were detected. Dental practitioners should be aware that despite higher prevalence of one distal and two mesial root canals, the mandibular second molars may also have one mesial and two distal root canals.

Parirokh, Masoud; V. Abbott, Paul; Yosefi, Mohammad Hosein; Hosseini, Hamid Reza

2014-01-01

381

Molar-mass measurement of a 28Si-enriched silicon crystal for determination of the Avogadro constant  

NASA Astrophysics Data System (ADS)

The molar mass of a 28Si-enriched crystal was measured at the National Metrology Institute of Japan to determine the Avogadro constant by the x-ray crystal density method as part of the International Avogadro Coordination project. The molar mass was determined by isotope ratio measurements using a multicollector inductively coupled plasma mass spectrometer combined with an isotope dilution technique. The 28Si-enriched crystal was dissolved in tetramethylammonium hydroxide and three different blended solutions were used to correct for mass bias in the measurement. The molar mass of the 28Si-enriched crystal was determined to be 27.976?970 09 g mol?1 with a standard uncertainty of 0.000?000 14 g mol?1. This corresponds to a relative standard uncertainty of 5.2 × 10?9. This result is consistent with measurements reported by the Physikalisch-Technische Bundesanstalt, Germany.

Narukawa, Tomohiro; Hioki, Akiharu; Kuramoto, Naoki; Fujii, Kenichi

2014-06-01

382

Influence of Ni/Co molar ratio on electromagnetic properties and microwave absorption performances for Ni/Co paraffin composites  

NASA Astrophysics Data System (ADS)

Ni and Co metallic microparticles with submicron size were synthesized with a simple wet chemical reduction method at a relatively low temperature. Then their morphologies and structures were characterized by SEM and XRD. Ni metallic microparticles have spherical-shape morphology with fcc crystalline structure, however, Co has a distinct leaf-like morphology with the fcc and hcp mixed phases crystalline structures. For the characterization of their electromagnetic properties, paraffin matrix composites containing different molar ratio Ni and Co mixture powder as fillers were prepared. It was found that both the electromagnetic properties and electromagnetic microwave absorption performances of absorber layer were remarkably influenced by Ni/Co molar ratio. The electromagnetic microwave absorption performances were significantly improved by blending Ni and Co metallic microparticles into paraffin matrix with changing Ni/Co molar ratio, and enhanced mechanism were discussed.

Yan, S. J.; Dai, S. L.; Ding, H. Y.; Wang, Z. Y.; Liu, D. B.

2014-05-01

383

Capsid Polypeptides of Mouse Elberfeld Virus I. Amino Acid Compositions and Molar Ratios in the Virion  

PubMed Central

The four major polypeptide chains (alpha, beta, gamma, delta) constituting the capsid protein of mouse Elberfeld (ME) virus were isolated by preparative electrophoresis on polyacrylamide gels, and the amino acid composition of each chain was determined. In addition, the molecular weights of the smallest chains of ME virus, mengovirus, and poliovirus, which had previously been determined by gel electrophoretic methods, were redetermined by gel filtration chromatography in 6 m guanidine hydrochloride. Each was found to have a molecular weight about 7,300. Using the reevaluated molecular weights and the known amino acid compositions of the chains, the molar ratio of each chain in the ME virion was determined by quantitative analysis of the distribution of radioactivity in the electrophoretically separated chains of virus which had been specifically radiolabeled with leucine or with methionine. Equimolar proportions of all four chains were found in the virion.

Stoltzfus, C. Martin; Rueckert, Roland

1972-01-01

384

A correlation study of occlusal and pulp chamber anatomy: the maxillary first molar.  

PubMed

The success of endodontic therapy is based on a number of criteria, particularly the conservation of tooth structure. This principle requires a systematic approach to pulp chamber access. By correlating the occlusal anatomy with the location of the root canal orifice, a dentist may find a number of guidelines for improving access design. In this in vitro study, the authors evaluated 29 human maxillary first molars. Digital radiographs and digital occlusal photographs were taken of each specimen before and after decoronation at the cementoenamel junction (CEJ). The three images were superimposed on one another and evaluated for occlusal and pulpal patterns. The thickness of the pulp chamber walls of the CEJ varied, based on the circumference of individual teeth. In addition, the canal orifices at the pulp chamber floor exhibited a consistent pattern relative to the cusp tips, which may assist in access design. PMID:17511364

Chogle, Sami; Mickel, Andre K; Self, McKinley; Bogle, John; Wright, Andrew

2007-01-01

385

Ionic limiting molar conductivity calculation of Li-ion battery electrolyte based on mode coupling theory.  

PubMed

A method is proposed based on mode coupling theory in which the ion transference number is introduced into the theory. The ionic limiting molar conductivities of LiPF6, LiClO4, LiBF4, LiCF3SO3, Li(CF3SO3)2N, LiC4F9SO3, and LiAsF6 in PC(propylene carbonate), GBL(gamma-butyrolactone), PC(propylene carbonate)/EMC(ethylmethyl carbonate), and PC(propylene carbonate)/DME(dimethoxyethane) are calculated based on this method, which does not involve any adjustable parameter. The results fit well to the literature data which are calculated by an empirically adjusted formula. This presents a potential way to calculate the conductivities of Li-ion battery electrolytes. PMID:16375275

He, Xiangming; Pu, Weihua; Han, Jingli; Chen, Jian; Lu, Jiufang; Jiang, Changyin; Wan, Chunrong

2005-12-15

386

Sonic hedgehog signaling is critical for cytodifferentiation and cusp formation in developing mouse molars.  

PubMed

The present study was designed to investigate the direct role of Shh molecule on cytodifferentiation and cusp formation. Affi-gel blue beads soaked in exogenous Shh-N, Shh antibody or BSA control protein were implanted between the epithelium and mesenchyme of isolated molar germs at the cap stage. The recombinants were grafted for culture under the kidney capsules respectively. In compared to the control, additional Shh-N protein could not enhance the ameloblasts and odontoblasts differentiation of the explanted tooth germs. While, application of Shh antibody retarded these events. After 4 weeks of subrenal culture, the teeth dissected from the explants treated with Shh-N were multicuspid. Most of the teeth harvested from the Shh antibody group were small and single irregularly shaped cusp was visible. The main cusp height in this group was reduced. The results indicated Shh signaling pathway is critical for odontoblast and ameloblast differentiation and patterns cusp formation. PMID:17786571

Zhang, Lu; Hua, Fang; Yuan, Guo-Hua; Zhang, Yan-Ding; Chen, Zhi

2008-02-01

387

[Prediction and estimation on molar response values of alkanes by using molecular path vector].  

PubMed

A new method based on a novel molecular topological index vector, called the molecular path vector (MPV), of alkane molecules is proposed and employed for estimation and prediction of the molar response values of various alkanes. The novel MPV, p = (P1, P2, P3, P4, P5, P6, P7, P8, P9, P10)', which derived directly from the interaction terms of molecular graph, is used to characterize well molecular structures of all alkanes from one through ten or eleven carbon atoms. It showed that there exists very good correlation between the MPV elements and molar response values on both FID and TCD detectors in classical gas chromatography. Based on the given calibration set with different sample numbers and by using the practical multiple linear regression, the quantitative structure-response relationship (QSRR) equations, for the molar response values (SM) on both FID and TCD, are respectively given as follows: SM(FID) = 15.4004881 + 17.9905995 X1 - 0.1652116 X2 - 0.6974103 X3 - 0.8452390 X4 - 0.2671000 X5 - 1.5657273 X6 + 0.0944440 X7, n = 50, m = 7, r = 0.9976, ST = 26.132, SR = 1.965 1, Ev = 99.72%, RMS = 1.801, F = 1231.71 SM(TCD) = 11.9946996 + 29.1490916 X1 - 4.7451669 X2 - 3.7673385 X3 - 1.4948330 X4 - 1.6278831 X5 - 0.7934611 X6 - 3.0566093 X7, n = 32, m = 7, r = 0.9968, ST = 15.72, SR = 1.4310, Ev = 99.59%, RMS = 1.239, F = 531.227 where the independent descriptor variables, X1-X7, refer to the elements, P1, P2, P3, P4, P5, P6, P7 in the molecular path vector for all samples in both FID and TCD training sets; n, r, ST, SR, Ev, RMS and F are the sample number, regression coefficient, total standard deviation, standard residual deviation, explained variance, rooted mean squared error and F-statistic value, respectively. To test both models by using back-propagation neural network (BPNN) with the topological structure NN(7-4-2) and the cross validation through leave-one-out (LOO) procedure, the correlation coefficient of cross validation is over 0.96. Because there exists a quite good linear relationship between the molar responses and molecular path parameters, BPNN (r = 0.989 and 0.968) does not show its nonlinear advantage over multiple linear regression(MLR) (r = 0.9976 and 0.9968) in both presently examined cases, FID and TCD in the GC technique, for molecular modelling and quantitative prediction. PMID:12541731

Zhou, L P; Xia, Z N; Liu, S S; Zhang, M J; Li, Z L

2000-11-01

388

A radiochemical titrant for the determination of the operational molarity of solutions of acid proteinases.  

PubMed Central

N-Diazoacetyl-L-phenylalanine 3-phenyl[2,3-3H]propylamide was synthesized and shown to inhibit pepsin A (EC3,4,23.1) and cathepsin D (EC 3.4.23.5) irreversibly and stoicheiometrically in the presence of Cu2+. Quantitative separation of the inhibited enzyme from excess reagent by gel filtration followed by measurement of the radioactivity of the protein peak provided a method for determining the operational molarity of these enzymes. Several other putative active-site-directed irreversible inhibitors were synthesized, but were inactive. Data on the synthesis of these compounds have been deposited as Supplementary Publication SUP50096 (4 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1978) 169, 5.

Irvine, G B; Elmore, D T

1979-01-01

389

Size-dependent composition and molar extinction coefficient of PbSe semiconductor nanocrystals.  

PubMed

Atomic compositions and molar extinction coefficients of PbSe semiconductor nanocrystals were determined by atomic absorption spectrometry, UV-vis-NIR spectrophotometry, and transmission electron microscopy. The Pb/Se atomic ratio was found to be size-dependent with a systematic excess of Pb atoms in the PbSe nanocrystal system. Experimental results indicated that the individual PbSe nanocrystal was nonstoichiometric, consisting of a PbSe core and an extra layer of Pb atoms. For these nonstoichiometric PbSe semiconductor nanocrystals, we proposed a new computational approach to calculate the total number of Pb and Se atoms in different sized particles. This calculation played a key role on the accurate determination of the strongly size-dependent extinction coefficient, which followed a power law with an exponent of approximately 2.5. PMID:19435305

Dai, Quanqin; Wang, Yingnan; Li, Xinbi; Zhang, Yu; Pellegrino, Donald J; Zhao, Muxun; Zou, Bo; Seo, JaeTae; Wang, Yiding; Yu, William W

2009-06-23

390

Fracture Resistance of Non-Metallic Molar Crowns Manufactured with CEREC 3D  

NASA Astrophysics Data System (ADS)

Objectives. To compare fracture strength and fatigue resistance of ceramic (ProCAD, Ivoclar-Vivadent) (C) and resin composite (Paradigm MZ100, 3M/ ESPE) (R) crowns made with CEREC-3D. Methods. A prepared ivorine molar tooth was duplicated to produce 40 identical prepared specimens made of epoxy resin (Viade). Twenty (C) crowns and 20 (R) were cemented to their dies using resin cement. Ten of each group were subjected to compressive loading to fracture. The remaining 10 of each group were subjected to mechanical cyclic loading for 500,000 cycles. The survivors were subjected to compressive loading to fracture. Results. No significant difference in mean fracture load was found between the two materials. However, only 30% of the (C) crowns vs. 100% of the (R) crowns survived the cyclic loading test. Conclusions. (R) crowns demonstrated higher fatigue Resistance than (C) crowns in-vitro and might better resist cracking in-vivo.

Madani, Dalia A.

391

Determination of the solubility of crystalline low molar mass compounds in polymers by differential scanning calorimetry.  

PubMed

A mathematical equation has been derived to calculate the liquidus for a binary system consisting of an amorphous polymer and a crystalline low molar mass compound. The experimental input to this equation is an interaction enthalpy, which is derived from the variation of the melting enthalpy with composition in differential scanning calorimetry (DSC) experiments. The predictive power of the equation has been tested with mixtures of acetylsalicylic acid, carbamazepine, or intraconazole with poly(ethylene glycol) as well as mixtures of carbamazepine with poly(acrylic acid), poly(hydroxystyrene), or poly(vinylpyrrolidone). It has been confirmed that the evaluation of the melting enthalpy in DSC is a suitable method to identify the preferred solute-polymer combinations for thermodynamically stable molecular dispersions. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci. PMID:24723307

Rager, Timo

2014-06-01

392

Infected Dentigerous Cyst of Maxillary Sinus Arising from an Ectopic Third Molar  

PubMed Central

A dentigerous cyst or follicular cyst is a form of odontogenic cyst. It is believed that it forms during the development of the tooth and is associated with pressure exerted by the crown of an unerupted (or partially erupted) tooth on the fluid within the follicular space. Typically, dentigerous cysts are painless and discovered during routine radiographic examination. However, they may be large and result in a palpable mass. Additionally, as they grow they displace adjacent teeth. They almost exclusively occur in permanent dentition. The cyst is lined by stratified squamous non-keratinizing epithelium. About 70% of dentigerous cysts occur in the mandible and 30% in the maxilla. Dentigerous cysts associated with ectopic teeth within the maxillary sinus are very rare. We report radiologic and pathologic features in a rare case of infected dentigerous cyst of maxillary sinus arising from an ectopic third molar in a 21-year-old female patient.

Guruprasad, Yadavalli; Chauhan, Dinesh Singh; Kura, Umashankar

2013-01-01

393

The antibacterial effects of ornidazole on primary molars with infected pulps.  

PubMed

The purpose of this study was to investigate the antibacterial effects of a short-term topical application of ornidazole on anaerobic microorganisms. The antibacterial properties of such materials against organisms at infected primary root canals have not been well documented. Twenty infected primary molars in this study were treated using ornidazole (Biteral, Roche). The bacterial contents of the roots were collected with sterile paper points before the application. Freshly mixed ornidazole and sterile saline were placed into the root canals. After 1 week, the bacterial contents of the root canals were collected again. Microbiological analyses were made. Based on our results, it appears that the antibacterial activity of ornidazole caused significant changes in rates of microorganisms (94.53% reduction). PMID:11306789

Kargül, B; Kadir, T

2001-01-01

394

Facial Pain Associated with CPAP Use: Intra-Sinusal Third Molar  

PubMed Central

Objective. This paper describes a patient with left hemifacial pain elicited by the use of a CPAP mask. Case Report. A 74-year-old man was referred with a history of pain in the left maxillary sinus related to the use of his CPAP interface, thereby prohibiting the use of the latter. Computed tomography revealed an intra-sinusal ectopic third molar in the left maxillary sinus floor corresponding to the painful area. After removal of the ectopic tooth under local anesthesia by a Caldwell-Luc approach, the patient was relieved of his symptoms. Conclusion. Although an ectopic tooth in the maxillary sinus is rare, this case points out the importance of actively looking for a regional problem if patients cannot tolerate the CPAP interface since this can lead to issues of incompliance and medical complications due to the untreated obstructive sleep apnoea syndrome.

Mermod, Maxime; Broome, Martin; Hoarau, Remy; Zweifel, Daniel

2014-01-01

395

The influence of a packable resin composite, conventional resin composite and amalgam on molar cuspal stiffness.  

PubMed

Packable resin composites may offer improved properties and clinical performance over conventional resin composites or dental amalgam. This in vitro study examined the cuspal stiffness of molars restored with a packable resin composite, a conventional posterior microfilled resin composite and amalgam. Forty-eight intact caries-free human third molars were distributed into four treatment groups (n=12) so that the mean cross-sectional areas of all groups were equal. Standardized MOD cavity preparations were made and specimens restored using one of four restorative materials: (1) a spherical particle amalgam (Tytin); (2) Tytin amalgam with a dentin adhesive liner (OptiBond Solo); (3) a conventional microfilled posterior resin composite (Heliomolar); (4) a packable posterior resin composite (Prodigy Posterior). Cuspal stiffness was measured using a Bionix 200 biomaterials testing machine (MTS). Specimens were loaded vertically to 300 N at a crosshead speed of 1.0 mm/minute. Stiffness was measured at 10 intervals: (1) prior to cavity preparation (intact); (2) following cavity preparation, but before restoration; (3) seven days after restoration; then (4) 1, 2, 3, 4, 5, 6 and 12 months after restoration. All specimens were stored at 37 degrees C in deionized water throughout the study and thermocycled (5 degrees/55 degrees C; 2000 cycles) monthly for 12 months. Repeated Measures ANOVA revealed significant differences among treatment groups over time (p<0.0001). Cavity preparation reduced cuspal stiffness by more than 60%. At 12 months, the cuspal stiffness of restored teeth was, on average, 58% that of intact specimens. Neither the packable nor the conventional resin composite increased cuspal stiffness over that of amalgam. PMID:12216572

Molinaro, J D; Diefenderfer, K E; Strother, J M

2002-01-01

396

NLRP7 or KHDC3L genes and the etiology of molar pregnancies and recurrent miscarriage.  

PubMed

Women with mutation in both alleles of the NLRP7 or C6orf221/KHDC3L genes are predisposed to diploid biparental moles, but it has also been suggested that mutation in these genes can predispose to diploid androgenetic or triploid moles and to other kinds of reproductive wastage. We have investigated the association between molar pregnancy and recurrent miscarriages regarding changes in the NLRP7 and C6orf221/KHDC3L genes. Our study group can be divided into three sub-cohorts: (i) women having had at least one molar pregnancy and at least two non-mole miscarriages, (ii) women having had recurrent androgenetic hydatidiform moles and (iii) women having had one diploid androgenetic hydatidiform mole and a relative having had a hydatidiform mole (familial hydatidiform moles). We observed a statistically non-significant tendency of non-synonymous variants in NLRP7 to be more frequent in women with familial hydatidiform mole and in women with female family members with hydatidiform mole or non-mole miscarriage compared with women with no family history of mole or miscarriage. However, we did not find any unequivocal pathogenic mutations (the term 'unequivocal pathogenic mutations' refers to mutations that indubitably have a pathogenic effect on the affected woman) in NLRP7 or C6orf221/KHDC3L in any of the women in the study group. This indicates that recurrent miscarriages plus hydatidiform mole, recurrent androgenetic hydatidiform moles and familial androgenetic hydatidiform moles in general do not have the same monogenetic etiology as familiar diploid biparental moles. PMID:23963444

Andreasen, L; Christiansen, O B; Niemann, I; Bolund, L; Sunde, L

2013-11-01

397

Lipid Concentration and Molar Ratio Boundaries for the Use of Isotropic Bicelles  

PubMed Central

Bicelles are model membranes generally made of long-chain dimyristoylphosphatidylcholine (DMPC) and short-chain dihexanoyl-PC (DHPC). They are extensively used in the study of membrane interactions and structure determination of membrane-associated peptides, since their composition and morphology mimic the widespread PC-rich natural eukaryotic membranes. At low DMPC/DHPC (q) molar ratios, fast-tumbling bicelles are formed in which the DMPC bilayer is stabilized by DHPC molecules in the high-curvature rim region. Experimental constraints imposed by techniques such as circular dichroism, dynamic light scattering, or microscopy may require the use of bicelles at high dilutions. Studies have shown that such conditions induce the formation of small aggregates and alter the lipid-to-detergent ratio of the bicelle assemblies. The objectives of this work were to determine the exact composition of those DMPC/DHPC isotropic bicelles and study the lipid miscibility. This was done using 31P nuclear magnetic resonance (NMR) and exploring a wide range of lipid concentrations (2–400 mM) and q ratios (0.15–2). Our data demonstrate how dilution modifies the actual DMPC/DHPC molar ratio in the bicelles. Care must be taken for samples with a total lipid concentration ?250 mM and especially at q ? 1.5–2, since moderate dilutions could lead to the formation of large and slow-tumbling lipid structures that could hinder the use of solution NMR methods, circular dichroism or dynamic light scattering studies. Our results, supported by infrared spectroscopy and molecular dynamics simulations, also show that phospholipids in bicelles are largely segregated only when q > 1. Boundaries are presented within which control of the bicelles’ q ratio is possible. This work, thus, intends to guide the choice of q ratio and total phospholipid concentration when using isotropic bicelles.

2014-01-01

398

Evaluation of the Restoration Success of Endodontic Therapy of the Primary Molars  

PubMed Central

Objectives: The aim of this study was to evaluate the clinical and radiographic success rates of pulpotomized primary molar teeth restored with a compomer material with using United States Public Health Service (USPHS) criteria. Methods: In 173 primary molars of 156 child patients, aged within 4–9 years (mean age: 6.1±1.4 years), conventional pulpotomy treatment were performed. The teeth treated using calcium hydroxide, formocresol or ferric sulphate. After pulpotomy procedure, teeth were restored with compomer material. The teeth were evaluated as clinically and radiographically during a period of 12–24 months. Both of success of pulpotomy treatment and also restorative material (compomer material) were evaluated during follow-up period. The data were assessed with chi-square test. Results: At the end of the first year, 45% of initial treated teeth were checked, but only 18% were checked at the end of the second year. The first year success rates in the groups treated with CH, FC, and FS were 87.5%, 95%, and 79%, respectively, and, as the number of controllable patients was lower, the success rates on available teeth were determined to be 88.3% and 80%, respectively, according to the materials at the end of the second year. Restorations having been made, they were analyzed in accordance with USPHS criteria. Conclusions: At the end of the first year, 67.5% of compomer restorations were detected to be original and healthy and at the end of the second year, 57% were deemed healthy. No statistically significant relationships were found between marginal adaptation, secondary caries and pulpotomy success (chi-square test, P>.05). Among the three groups, there is no significant difference in terms of success. The least successful age group was defined as 4–6 years.

Kirzioglu, Zuhal; Gungor, Ozge Erken; Ciftci, Z. Zahit

2011-01-01

399

Patterns of morphological variation in enamel-dentin junction and outer enamel surface of human molars.  

PubMed

Tooth crown patterning is governed by the growth and folding of the inner enamel epithelium (IEE) and the following enamel deposition forms outer enamel surface (OES). We hypothesized that overall dental crown shape and covariation structure are determined by processes that configurate shape at the enamel-dentine junction (EDJ), the developmental vestige of IEE. This this hypothesis was tested by comparing patterns of morphological variation between EDJ and OES in human permanent maxillary first molar (UM1) and deciduous second molar (um2). Using geometric morphometric methods, we described morphological variation and covariation between EDJ and OES, and evaluated the strength of two components of phenotypic variability, canalization and morphological integration, in addition to the relevant evolutionary flexibility, i.e. the ability to respond to selective pressure. The strength of covariation between EDJ and OES was greater in um2 than in UM1, and the way that multiple traits covary between EDJ and OES was different between these teeth. The variability analyses showed that EDJ had less shape variation and a higher level of morphological integration than OES, which indicated that canalization and morphological integration acted as developmental constraints. These tendencies were greater in UM1 than in um2. On the other hand, EDJ and OES had a comparable level of evolvability in these teeth. Amelogenesis could play a significant role in tooth shape and covariation structure, and its influence was not constant among teeth, which may be responsible for the differences in the rate and/or period of enamel formation. PMID:24689536

Morita, Wataru; Yano, Wataru; Nagaoka, Tomohito; Abe, Mikiko; Ohshima, Hayato; Nakatsukasa, Masato

2014-06-01

400

Partial Molar Liquidus Temperatures of Multivalent Elements in Multicomponent Borosilicate Glass  

SciTech Connect

A multicomponent borosilicate glass containing several multivalent elements (Fe, Ni, Cr, Mn) and precipitating (Fe,Ni,Mn,Cr)(Fe,Cr,Mn)2O4 spinel as its primary phase, was equilibrated with the gas phase over the range of oxygen partial pressures, from 10{sup -13} Pa to 10{sup 5} Pa and temperatures, T, from 850 C to 1300 C. The oxidation-reduction equilibrium of Fe in the glass was measured with Mossbauer spectroscopy and wet colorimetry. These data were combined with oxidation-reduction equilibria for Fe, Ni, and Cr in a borosilicate frit of a similar composition found in the literature to estimate concentrations of Fe(II), Fe(III), Ni(II), Cr(II), Cr(III), and Cr(VI) as functions of T. Measured liquidus temperature (TL) data for the test glasses within the same range were then added to a critically evaluated TL database composed of multicomponent borosilicate glasses within the spinel primary crystalline phase field. The set of partial molar liquidus temperatures for elements other than oxygen determined from this database was then augmented by values for Fe(II), Fe(III), Cr(II), Cr(III), and Cr(VI). A 0.1-mol% change in the metal ion concentration increases TL as follows: Fe(II) by 4.6 C, Fe(III) by 2.8 C, Cr(II) by 185?C, Cr(III) by 66 C, and Cr(VI) by -17 C. The calculated TL based on partial molar liquidus temperatures agreed with the measured TL in the range from 10{sup -13} Pa to 10{sup 5} Pa.

Hrma, Pavel R. (BATTELLE (PACIFIC NW LAB)); Izak, Pavel (ASSOC WESTERN UNIVERSITY); Vienna, John D. (BATTELLE (PACIFIC NW LAB)); Thomas, M-L (.); Irwin, G M. (.)

2002-01-01

401

Treatment Outcomes of Primary Molars Direct Pulp Capping after 20 Months: A Randomized Controlled Trial  

PubMed Central

Introduction The aim of this randomized controlled trial was to compare the radiographic and clinical success rates of direct pulp capping (DPC) using ProRoot mineral trioxide aggregate (MTA) or calcium enriched mixture (CEM). Methods and Materials A total of 42 symptom-free carious vital primary molars (21 pairs) were selected in this split mouth trial and randomly pulpotomized in two experimental groups. Pinpoint pulp exposures were covered by the same blinded operator with MTA or CEM, and then restored by amalgam. Radiographic and clinical successes were evaluated at 20 month follow-up. Data were statistically analyzed using McNemar test. Results Nineteen patients were available for 20-month follow-up; only one failed tooth was extracted in the CEM group. All available teeth were symptom-free, however, the final evaluated success rate was 89% in CEM (CI 95%: 0.82-0.96) and 95% in MTA (CI 95%: 0.85-1) groups without statistical difference (P=0.360). Worst case scenario was applied for missing value analysis; assuming that the 2 lost cases in CEM group had failed and the only lost case in MTA group was due to treatment success, as a result the success of CEM and MTA were 81% (CI 95%: 0.72-0.90) and 95% (CI 95%:0.85-1), respectively, with no statistical difference (P=0.078). In the reverse scenario, the success of MTA and CEM were 86% (CI 95%: 0.78-0.94) and 90% (CI 95%: 0.82-0.98), respectively; again with no statistical difference (P=0.479). Conclusion Effectiveness of MTA and CEM biomaterials for primary molars’ DPC was similar; CEM can be a suitable alternative for MTA.

Fallahinejad Ghajari, Masoud; Asgharian Jeddi, Tahereh; Iri, Sonay; Asgary, Saeed

2013-01-01

402

Comparison of Propofol-Remifentanil Versus Propofol-Ketamine Deep Sedation for Third Molar Surgery  

PubMed Central

This study aimed to compare continuous intravenous infusion combinations of propofol-remifentanil and propofol-ketamine for deep sedation for surgical extraction of all 4 third molars. In a prospective, randomized, double-blinded controlled study, participants received 1 of 2 sedative combinations for deep sedation for the surgery. Both groups initially received midazolam 0.03 mg/kg for baseline sedation. The control group then received a combination of propofol-remifentanil in a ratio of 10 mg propofol to 5 ?g of remifentanil per milliliter, and the experimental group received a combination of propofol-ketamine in a ratio of 10 mg of propofol to 2.5 mg of ketamine per milliliter; both were given at an initial propofol infusion rate of 100 ?g/kg/min. Each group received an induction loading bolus of 500 ?g/kg of the assigned propofol combination along with the appropriate continuous infusion combination . Measured outcomes included emergence and recovery times, various sedation parameters, hemodynamic and respiratory stability, patient and surgeon satisfaction, postoperative course, and associated drug costs. Thirty-seven participants were enrolled in the study. Both groups demonstrated similar sedation parameters and hemodynamic and respiratory stability; however, the ketamine group had prolonged emergence (13.6 ± 6.6 versus 7.1 ± 3.7 minutes, P = .0009) and recovery (42.9 ± 18.7 versus 24.7 ± 7.6 minutes, P = .0004) times. The prolonged recovery profile of continuously infused propofol-ketamine may limit its effectiveness as an alternative to propofol-remifentanil for deep sedation for third molar extraction and perhaps other short oral surgical procedures, especially in the ambulatory dental setting.

Kramer, Kyle J.; Ganzberg, Steven; Prior, Simon; Rashid, Robert G.

2012-01-01

403

Lipid concentration and molar ratio boundaries for the use of isotropic bicelles.  

PubMed

Bicelles are model membranes generally made of long-chain dimyristoylphosphatidylcholine (DMPC) and short-chain dihexanoyl-PC (DHPC). They are extensively used in the study of membrane interactions and structure determination of membrane-associated peptides, since their composition and morphology mimic the widespread PC-rich natural eukaryotic membranes. At low DMPC/DHPC (q) molar ratios, fast-tumbling bicelles are formed in which the DMPC bilayer is stabilized by DHPC molecules in the high-curvature rim region. Experimental constraints imposed by techniques such as circular dichroism, dynamic light scattering, or microscopy may require the use of bicelles at high dilutions. Studies have shown that such conditions induce the formation of small aggregates and alter the lipid-to-detergent ratio of the bicelle assemblies. The objectives of this work were to determine the exact composition of those DMPC/DHPC isotropic bicelles and study the lipid miscibility. This was done using (31)P nuclear magnetic resonance (NMR) and exploring a wide range of lipid concentrations (2-400 mM) and q ratios (0.15-2). Our data demonstrate how dilution modifies the actual DMPC/DHPC molar ratio in the bicelles. Care must be taken for samples with a total lipid concentration ?250 mM and especially at q ? 1.5-2, since moderate dilutions could lead to the formation of large and slow-tumbling lipid structures that could hinder the use of solution NMR methods, circular dichroism or dynamic light scattering studies. Our results, supported by infrared spectroscopy and molecular dynamics simulations, also show that phospholipids in bicelles are largely segregated only when q > 1. Boundaries are presented within which control of the bicelles' q ratio is possible. This work, thus, intends to guide the choice of q ratio and total phospholipid concentration when using isotropic bicelles. PMID:24797658

Beaugrand, Maïwenn; Arnold, Alexandre A; Hénin, Jérôme; Warschawski, Dror E; Williamson, Philip T F; Marcotte, Isabelle

2014-06-01

404

Root Canal Cleaning Efficacy of Rotary and Hand Files Instrumentation in Primary Molars  

PubMed Central

INTRODUCTION: Pulpectomy of primary teeth is commonly carried out with hand files and broaches; a tricky and time consuming procedure. The purpose of this in vitro study was to compare the cleaning efficacy and time taken for instrumentation of deciduous molars using hand K-files and Flex Master rotary system. MATERIALS AND METHODS: In this study, 68 canals of 23 extracted primary molars with at least two third intact roots and 7-12 mm length were selected. After preparing an access cavity, K-file size #15 was introduced into the root canal and India ink was injected with an insulin syringe. Sixty samples were randomly divided in to experimental groups in group I (n=30), root canals were prepared with hand K-files; in group II (n=30), rotary Flex Master files were used for instrumentation, and in group III 8 remained samples were considered as negative controls. After clearing and root sectioning, the removal of India ink from cervical, middle, and apical thirds was scored. Data was analyzed using student's T-test and Mann-Whitney U test. RESULTS: There was no significant difference between experimental groups cleaning efficacy at the cervical, middle and apical root canal thirds. Only the coronal third scored higher in the hand instrumented group (P<0.001). Instrumentation with Flex Master rotary files was significantly less time consuming (P<0.001). CONCLUSION: Although there was no difference in cleanliness efficacy at the apical and middle thirds, the coronal third was more effectively cleaned with hand files. Predictably, time efficiency was a significant advantage with rotary technique.

Nazari Moghaddam, Kiumars; Mehran, Majid; Farajian Zadeh, Hamideh

2009-01-01

405

A Physiological Permeability Study of Third Molar Dentine with Odontoblasts Preserved and Odontoblasts Free Preparations  

PubMed Central

Introduction Dentine a viable biological tissue forms an intimately related complex with the odontoblasts. Much has been question of the barrier properties of dentine within teeth and between teeth.. In human adults the odontoblasts are fully differentiated post-mitotic cells, which send its cytoplasmic processes into the dentinal tubules, yet various studies in the physic of fluid flow in dentine takes little recognition of its presence. The permeability of dentine has been implicated in a possible hydrodynamic mechanism by which rapid fluid movement in the tubules is thought to depolarise the nerve endings. Objective The innovative aim from this pilot investigation is to contribute to the understanding of the influence of odontoblasts on the permeability of human dentine. Methodology This study describes the permeability in odontoblast preserved and odontoblast free preparations in vitro i.e. comparing fluid flow across dentine in human third molars. The pulp tissues were removed from human third molars leaving the odontoblasts attached to the walls of the chamber. The specimens were then either fixed chemically (odontoblast-preserved specimens) or immersed in NaOH (odontoblast free specimens). Occlusal dentine was exposed by removing the enamel. The exposed dentine was placed in contact with water and the ingress of water into the pulp chamber was observed with a binocular microscope. A microlitre syringe was used to measure the volume of water accumulated at time intervals of several hours for up to 70 hours or more. Results The results showed that spontaneous flow continued in both preparations until equilibrium was reached. The relative final volumes were greater in the odontoblast free preparations than in the odontoblast preserved. Conclusion Water movement through odontoblast free dentine was believed to be driven by capillarity and through odontoblast preserved dentine by capillarity and osmotic pressure.

Ghazali, Farid Che

2000-01-01

406

Multivariate Analysis of Factors Affecting Presence and/or Agenesis of Third Molar Tooth.  

PubMed

To investigate the presence and/or agenesis of third molar (M3) tooth germs in orthodontics patients in Malaysian Malay and Chinese population and evaluate the relationship between presence and/or agenesis of M3 with different skeletal malocclusion patterns and sagittal maxillomandibular jaw dimensions. Pretreatment records of 300 orthodontic patients (140 males and 160 females, 219 Malaysian Malay and 81 Chinese, average age was 16.27±4.59) were used. Third-molar agenesis was calculated with respect to race, genders, number of missing teeth, jaws, skeletal malocclusion patterns and sagittal maxillomandibular jaw dimensions. The Pearson chi-square test and ANOVA was performed to determine potential differences. Associations between various factors and M3 presence/agenesis groups were assessed using logistic regression analysis. The percentages of subjects with 1 or more M3 agenesis were 30%, 33% and 31% in the Malaysian Malay, Chinese and total population, respectively. Overall prevalence of M3 agenesis in male and female was equal (P>0.05). The frequency of the agenesis of M3s is greater in maxilla as well in the right side (P>0.05). The prevalence of M3 agenesis in those with a Class III and Class II malocclusion was relatively higher in Malaysian Malay and Malaysian Chinese population respectively. Using stepwise regression analyses, significant associations were found between Mx (P<0.05) and ANB (P<0.05) and M3 agenesis. This multivariate analysis suggested that Mx and ANB were significantly correlated with the M3 presence/agenesis. PMID:24967595

Alam, Mohammad Khursheed; Hamza, Muhammad Asyraf; Khafiz, Muhammad Aizuddin; Rahman, Shaifulizan Abdul; Shaari, Ramizu; Hassan, Akram

2014-01-01

407

Multivariate Analysis of Factors Affecting Presence and/or Agenesis of Third Molar Tooth  

PubMed Central

To investigate the presence and/or agenesis of third molar (M3) tooth germs in orthodontics patients in Malaysian Malay and Chinese population and evaluate the relationship between presence and/or agenesis of M3 with different skeletal malocclusion patterns and sagittal maxillomandibular jaw dimensions. Pretreatment records of 300 orthodontic patients (140 males and 160 females, 219 Malaysian Malay and 81 Chinese, average age was 16.27±4.59) were used. Third-molar agenesis was calculated with respect to race, genders, number of missing teeth, jaws, skeletal malocclusion patterns and sagittal maxillomandibular jaw dimensions. The Pearson chi-square test and ANOVA was performed to determine potential differences. Associations between various factors and M3 presence/agenesis groups were assessed using logistic regression analysis. The percentages of subjects with 1 or more M3 agenesis were 30%, 33% and 31% in the Malaysian Malay, Chinese and total population, respectively. Overall prevalence of M3 agenesis in male and female was equal (P>0.05). The frequency of the agenesis of M3s is greater in maxilla as well in the right side (P>0.05). The prevalence of M3 agenesis in those with a Class III and Class II malocclusion was relatively higher in Malaysian Malay and Malaysian Chinese population respectively. Using stepwise regression analyses, significant associations were found between Mx (P<0.05) and ANB (P<0.05) and M3 agenesis. This multivariate analysis suggested that Mx and ANB were significantly correlated with the M3 presence/agenesis.

Alam, Mohammad Khursheed; Hamza, Muhammad Asyraf; Khafiz, Muhammad Aizuddin; Rahman, Shaifulizan Abdul; Shaari, Ramizu; Hassan, Akram

2014-01-01

408

Articaine For Surgical Removal of Impacted Third Molar; A Comparison With Lignocaine  

PubMed Central

Aim: Articaine is an amide local anesthetic that differs from other agents of its group due to the presence of thiophene ring instead of a benzene ring. Some researchers claim that articaine is superior to lidocaine in its biologic profile. The aim of the study is to compare the efficacy of articaine with that of lidocaine which has proven efficacy. Materials and method: This study was done on 50 subjects; 25 of them received 4 % articaine HCl with 1:100000 epinephrine and the next 25 received 2% lignocaine HCl with 1:100000 epinephrine. Time of injection, onset of anesthesia, amount of anesthetic injected were recorded. Efficacy was determined using visual analog scale. The values were statistically analyzed. Results: The mean onset time of anesthesia in study group was 2.07 ± 0.22 and 2.18 ± 0.26 minutes in comparison group. A mean duration of 4.28 +0.78 hours was seen with articaine group and 3.51 + 0.45 hours with the lignocaine group. No statistical difference between the two groups with regard to pain experience. Conclusion: Articaine has similar efficacy as that of lignocaine with slightly longer duration and can be used as an alternative to lignocaine in third molar surgeries. Clinical Significance: Increased availability of local anesthetics has improved interest in research about dental pain control. a quest for new methods of pain reduction is always justified. How to cite this article: R Shruthi, S N Kedarnath, S Mamatha N, Rajaram P, Dinesh B. Articaine For Surgical Removal of Impacted Third Molar; A Comparison With Lignocaine. J Int Oral Health 2013; 5(1):48-53.

Shruthi, R; Kedarnath, NS; Mamatha, NS; Rajaram, Prashanth; BhadraShetty, Dinesh

2013-01-01

409

Aripiprazole-Cyclodextrin Binary Systems for Dissolution Enhancement: Effect of Preparation Technique, Cyclodextrin Type and Molar Ratio  

PubMed Central

Objective(s): The aim of this work was to investigate the effect of the natural and the chemically modified form of cyclodextrins namely; ?-cyclodextrin (?-CD) and hydroxypropyl-?-cyclodextrin (HP-?-CD) respectively on the solubility and dissolution rate of aripiprazole; an antipsychotic medication showing poor aqueous solubility. Materials and Methods: Phase solubility of aripiprazole with the studied CDs and the complexation efficiency values (CE) which reflect the solubilizing power of the CDs towards the drug was performed. Solid binary systems of aripiprazole with CDs were prepared by kneading, microwave irradiation and freeze-drying techniques at 1:1 and 1:2 (drug to CD) molar ratios. Drug-CD physical mixtures were also prepared in the same molar ratios for comparison. The dissolution of aripiprazole-binary systems was carried out to select the most appropriate CD type, molar ratio and preparation technique. Results: Phase solubility study indicated formation of higher order complexes and the complexation efficiency values was higher for HP-?-CD compared to ?-CD. Drug dissolution study revealed that aripiprazole dissolution was increased upon increasing the CD molar ratio and, the freeze-drying technique was superior to the other studied methods especially when combined with the HP-?-CD. The cyclodextrin type, preparation technique and molar ratio exhibited statistically significant effect on the drug dissolution at P? 0.05. Conclusion: The freeze-dried system prepared at molar ratio 1:2 (drug: CD) can be considered as efficient tool for enhancing aripiprazole dissolution with the possibility of improving its bioavailability.

M. Badr-Eldin, Shaimaa; A. Ahmed, Tarek; R Ismail, Hatem

2013-01-01

410

Thermodynamics of aqueous methyldiethanolamine (MDEA) and methyldiethanolammonium chloride (MDEAH +Cl ?) over a wide range of temperature and pressure: Apparent molar volumes, heat capacities, and isothermal compressibilities  

Microsoft Academic Search

Apparent molar volumes of aqueous methyldiethanolamine and its salt were determined with platinum vibrating tube densitometers over a range of temperatures from 283K?T?576K and at pressures from 0.1MPa to 20MPa. Apparent molar heat capacities were obtained using a Sodev Picker flow microcalorimeter at a pressure of 0.1MPa and within the temperature range of 283K?T?328K. Apparent molar adiabatic and isothermal compressibilities

B. Hawrylak; R. Palepu; Peter R. Tremaine

2006-01-01

411

Effect of two routes of administration of dexamethasone on pain, edema, and trismus in impacted lower third molar surgery  

Microsoft Academic Search

Purpose  The aim of the present study was to compare pain, edema, and trismus in the postoperative period following third molar surgery\\u000a using 8 mg of dexamethasone administered either orally or through local injection.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  A prospective, controlled, randomized trial was carried out involving 60 lower third molar surgeries in 67 patients between\\u000a October 2008 and June 2009. The sample was randomly divided

Antonio Azoubel Antunes; Rafael Linard Avelar; Evandro Carneiro Martins Neto; Riedel Frota; Emanuel Dias

412

New nomenclature for extra canals based on four reported cases of maxillary first molars with six canals.  

PubMed

This clinical article describes 4 different case reports of maxillary first molars with unusual anatomy of 6 root canals and their endodontic management. Treating these additional canals in maxillary first molars might be challenging. Inability to locate and properly treat these extra canals might lead to failures. A thorough knowledge of root canal morphology and the proper use of microscopes increase chances for successful clinical results. Because presence of these extra canals is not unusual and naming these canals still remains elusive, a new nomenclature is suggested for ease of communication. PMID:20478469

Karthikeyan, Kittappa; Mahalaxmi, Sekar

2010-06-01

413

Ultrasonic bone surgery in the treatment of impacted lower third molar associated to a complex odontoma: a case report  

PubMed Central

Summary The removal of impacted mandibular third molar is a common surgical procedure entailing some risk of complications, especially when the tooth and the inferior alveolar nerve and/or lingual cortical plate are in close proximity. A technique that can reduce the possibility of damage is the Ultra Sonic Bone Surgery. The aim of this report is to present a paradigmatic case of an impacted mandibular third molar closely associated with a complex odontoma, which was treated with the Ultrasonic Bone Surgery (UBS) device. This technique appeared to be a valid alternative to manual or mechanical treatment, strongly minimizing trauma to the inferior alveolar nerve, vascular tissues, or surrounding dental tissues.

Cristalli, Maria Paola; La Monaca, Gerardo; Sgaramella, Nicola; Vozza, Iole

2012-01-01

414

Effect of temperature on the excess molar volumes of some alcohol + aromatic mixtures and modelling by cubic EOS mixing rules  

Microsoft Academic Search

Densities of the (methanol+benzene), (ethanol+benzene), (methanol+chlorobenzene) and (ethanol+chlorobenzene) mixtures have been measured at six temperatures (288.15, 293.15, 298.15, 303.15, 308.15 and 313.15K) and 101.33kPa. Excess molar volumes VE were determined and fitted by the Redlich–Kister equation. It was observed that in all cases VE increases with rising of temperature. The values of limiting excess partial molar volumes have been calculated,

Slobodan P. Šerbanovi?; Mirjana Lj. Kijev?anin; Ivona R. Radovi?; Bojan D. Djordjevi?

2006-01-01

415

Analysis of a force system for upper molar distalization using a trans-palatal arch and mini-implant: a finite element analysis study.  

PubMed

The purpose of this study was to analyse distal movements of molars in a force system using a trans-palatal arch (TPA), fixed to the maxillary first molar, and mini-implants placed at the palatal midline, considering the diagnostic standard for placement site in association with variation in upper molar locations, using finite element (FE) analysis. Three-dimensional FE models, divided by the differing direction of traction force, mesiodistal locations of the left and right molars, and the lateral location of the mini-implant were constructed. (1) When a traction force was fixed from the height of alveolar crest to the mini-implant placed at the middle of palate, the molars underwent bodily movement. (2) When the location of the mini-implant was moved to the left of the midline, the amount of distal movement of the left molar increased. When the mesiodistal locations of the left and right molars differed, the amount of distal movement of the molar located mesially was larger than that of the contralateral molar, even when the mini-implant was located on the midline. PMID:22952153

Ueno, Satoshi; Motoyoshi, Mitsuru; Mayahara, Kotoe; Saito, Yoko; Akiyama, Yuko; Son, Seil; Shimizu, Noriyoshi

2013-10-01

416

Adsorption rate of methane and carbon dioxide on activated carbon by the semi-batch constant molar flow rate method  

Microsoft Academic Search

The adsorption of methane and carbon dioxide on activated carbon pellets have been studied by a semi-batch constant molar flow rate method, which was first proposed by Do (1995). In this method, a very low and constant flow of adsorbate was introduced into a pre-evacuated adsorption cell. The pressure of the cell was monitored as a function of time and

I. Prasetyo; D. D. Do

1998-01-01

417

Rheological Properties and Structure of Aqueous Solutions of Polysaccharides. Solutions of Mixtures of Sodium Carboxymethylcellulose Fractions of Different Molar Mass  

Microsoft Academic Search

Rigorous relations are proposed for calculating the additive values of activation parameters of viscous flow of solutions of polymer mixtures. The point of view that the cause of deviation of the viscosity of solutions of Na-CMC fractions of the same chemical composition but significantly different molar mass from the additive values is the formation of a supermolecular structure common to

A. N. Prusov; S. M. Prusova; I. V. Ryabinina

2003-01-01

418

Can Learning from Molar and Modular Worked Examples Be Enhanced by Providing Instructional Explanations and Prompting Self-Explanations?  

ERIC Educational Resources Information Center

In two experiments we explored how learning from traditional molar worked-out examples--focusing on problem categories and their associated overall solution procedures--as well as from more efficient modular worked-out examples--where intrinsic cognitive load is reduced by breaking down complex solutions into smaller meaningful solution…

Gerjets, Peter; Scheiter, Katharina; Catrambone, Richard

2006-01-01

419

A combined frontal and maxillary sinus approach for repulsion of the third maxillary molar in a horse.  

PubMed Central

The 3rd maxillary molar is a difficult tooth to remove by extraction or repulsion. A combined frontal and maxillary approach provides good exposure for repulsion of this tooth, debridement of the sinuses, and placement of an alveolar seal. The improved exposure should minimize operative difficulties and postoperative complications. Images Figure 1.

Boutros, C P; Koenig, J B

2001-01-01

420

Effect of clinical guidelines on practice for extraction of lower third molars: study of referrals in 1997 and 2000.  

PubMed

We made a retrospective study of patient records for 3-month periods during 1997 and 2000 to assess changes in referral patterns and decision-making for extraction of lower third molars after publication of national guidelines. A total of 277 patients were referred to the department for extraction of lower third molars in 1997 and 234 in 2000 while overall referrals increased from 884 to 979. The number having extractions dropped from 243/277 (88%) to 190/234 (81%) of those referred (P=0.05) and of those operated on, bilateral removal dropped from 120/243 (49%) to 65/190 (34%) (P=0.002). The number of patients operated on under general anaesthesia reduced from 161/243 (66%) to 103/190 (54%) (P=0.01). However, women remained more likely to get treatment under general anaesthesia than men. In conclusion, there was a reduction in referrals for extraction of third molars, the proportion of referred patients having extractions, the number of bilateral operations, and changes in the choice of anaesthesia over the period of introduction of national guidelines on operations for third molars. PMID:14614863

Jamileh, Y; Pedlar, J

2003-12-01

421

A high molar extinction coefficient mono-anthracenyl bipyridyl heteroleptic ruthenium(II) complex: synthesis, photophysical and electrochemical properties.  

PubMed

In our quest to develop good materials as photosensitizers for photovoltaic dye-sensitized solar cells (DSSCs), cis-dithiocyanato-4-(2,3-dimethylacrylic acid)-2,2'-bipyridyl-4-(9-anthracenyl-(2,3-dimethylacrylic)-2,2'-bipyridyl ruthenium(II) complex, a high molar extinction coefficient charge transfer sensitizer, was designed, synthesized and characterized by spectroscopy and electrochemical techniques. Earlier studies on heteroleptic ruthenium(II) complex analogues containing functionalized oligo-anthracenyl phenanthroline ligands have been reported and documented. Based on a general linear correlation between increase in the length of ?-conjugation bond and the molar extinction coefficients, herein, we report the photophysical and electrochemical properties of a Ru(II) bipyridyl complex analogue with a single functionalized anthracenyl unit. Interestingly, the complex shows better broad and intense metal-to ligand charge transfer (MLCT) band absorption with higher molar extinction coefficient (?(max) = 518 nm, e = 44900 M?¹ cm?¹), and appreciable photoluminescence spanning the visible region than those containing higher anthracenyl units. It was shown that molar absorption coefficient of the complexes may not be solely depended on the extended ?-conjugation but are reduced by molecular aggregation in the molecules. PMID:21642936

Adeloye, Adewale O; Ajibade, Peter A

2011-01-01

422

Morphometry, scanning electron microscopy and x-ray spectral microanalysis of protostylid pits on human lower third molars  

Microsoft Academic Search

Protostylid pits on 50 lower third molars were studied. The depth and width of the pits, the thickness of the enamel at the pit bottom and the concavity of the dentino-enamel junction under the pit were measured by light microscopy. The pit content was examined by scanning electron microscopy and X-ray spectral microanalysis. The results show that the morphometric variables

Dominik Gašperši?

1996-01-01

423

Calcium enriched mixture cement for primary molars exhibiting root perforations and extensive root resorption: report of three cases.  

PubMed

In primary molars with root perforations of endodontic origin, tooth extraction and space maintainer are recommended. Calcium-enriched mixture (CEM) cement is a new biomaterial demonstrating favorable sealability/biocompatibility. This report presents a novel treatment modality for cases of primary molar teeth with root perforations associated with a periodontal lesion due to extensive inflammatory root resorption, whereby CEM was used as a perforation repair/pulpotomy biomaterial. Three cases of primary molar root perforations due to inflammatory resorption were selected; all cases were associated with furcal lesions of endodontic origin. Pulp chambers were accessed/irrigated with NaOCl; the root canal orifices were filled with CEM and restored with stainless steel crowns. Clinical/radiographic examinations up to 17 months revealed that all teeth were functional and free of signs/symptoms of infection and all had complete bone healing. Further trials are suggested to confirm CEM use for management of root perforations in primary molars exhibiting root perforation. PMID:24717704

Tavassoli-Hojjati, Sara; Kameli, Somayeh; Rahimian-Emam, Sara; Ahmadyar, Maryam; Asgary, Saeed

2014-01-01

424

A facile no-carrier-added one pot micro-molar scale radiosynthesis of 2-[¹?C]-uracil.  

PubMed

A facile no-carrier-added one pot micro-molar scale radiolabelled synthesis of 2-[(14)C]-uracil from [(14)C]-urea and propiolic acid in the presence of polyphosphoric acid (PPA) with an yield of 48.33% and with radiochemical purity of 98% is reported in this paper. PMID:23208239

Srinivas, G; Unny, V K P; Mukkanti, K; Choudary, B M

2013-02-01

425

Familial molar tissues due to mutations in the inflammatory gene, NALP7 , have normal postzygotic DNA methylation  

Microsoft Academic Search

An imprinting disorder has been believed to underlie the etiology of familial biparental hydatidiform moles (HMs) based on the abnormal methylation or expression of imprinted genes in molar tissues. However, the extent of the epigenetic defect in these tissues and the developmental stage at which the disorder begins have been poorly defined. In this study, we assessed the extent of

Ugljesa Djuric; Osman El-Maarri; Barbara Lamb; Rork Kuick; Muheiddine Seoud; Philippe Coullin; Johannes Oldenburg; Samir Hanash; Rima Slim

2006-01-01

426

Electrical Insulating and Heat-Resistive Properties of PDMS-TEOS Hybrid with Different Molar Ratio of TEOS to PDMS  

Microsoft Academic Search

The hybrids prepared from polydimethylsiloxane (PDMS) and tetraethoxysilane (TEOS) have been well known to be rubbery hybrid materials. In this report, the authors have investigated the electrical insulating and heat resistive properties of the hybrids by changing the molar ratio of TEOS to PDMS. The electrical insulating properties are evaluated by volume resistivity and AC breakdown strength at room temperature.

Makoto Sugiura; Fumitoshi Imasato; Atsushi Ohno; Yusuke Aoki; Shuhei Nakamura; Tetsushi Okamoto; Takuya Shindou

2007-01-01

427

Molar Tooth Sign in Fetal Brain Magnetic Resonance Imaging Leading to the Prenatal Diagnosis of Joubert Syndrome and Related Disorders  

Microsoft Academic Search

Joubert syndrome is a rare autosomal recessive disorder characterized by ataxia, developmental delay, and oculomotor and respiratory abnormalities in relation to cerebellar vermian and midbrain dysgenesis. The midbrain dysgenesis is responsible for the molar tooth sign on axial magnetic resonance imaging (MRI). This classic hallmark of Joubert syndrome has been identified in other disorders sharing overlapping clinical and radiologic features

Joel Fluss; Susan Blaser; David Chitayat; Hani Akoury; Phyllis Glanc; Martin Skidmore; Charles Raybaud

2006-01-01

428

Slit1 is specifically expressed in the primary and secondary enamel knots during molar tooth cusp formation  

Microsoft Academic Search

The shape and diversity of the mammalian molar teeth is suggested to be regulated by the primary and secondary enamel knots, which are putative epithelial signaling centers of the tooth. In search of novel molecules involved in tooth morphogenesis, we analyzed mRNA expression of Slit1, -2 and -3, earlier characterized as secreted signals needed for axonal pathfinding and their two

Sigbjørn Løes; Keijo Luukko; Inger Hals Kvinnsland; Päivi Kettunen

2001-01-01

429

Identification of a novel putative signaling center, the tertiary enamel knot in the postnatal mouse molar tooth  

Microsoft Academic Search

The final shape of the molar tooth crown is thought to be regulated by the transient epithelial signaling centers in the cusp tips, the secondary enamel knots (SEKs), which are believed to disappear after initiation of the cusp growth. We investigated the developmental fate of the signaling center using the recently characterized Slit1 enamel knot marker as a lineage tracer

Keijo Luukko; Sigbjørn Løes; Tomasz Furmanek; Karianne Fjeld; Inger Hals Kvinnsland; Paivi Kettunen

2003-01-01

430

A Review on Prediction Methods for Molar Enthalpies of Vaporization of Hydrocarbons: The ELBA Method as the Best Answer  

NASA Astrophysics Data System (ADS)

A review on prediction methods for molar enthalpies of vaporization at T = 298.15 K of hydrocarbons is presented. A new method is proposed and compared with six of the most common used ones from the literature. This new method, the extended Laidler bond additivity (ELBA), was applied to the prediction of standard molar enthalpies of vaporization of hydrocarbons (alkanes, alkenes, alkynes, polyenes, poly-ynes, cycloalkanes, cycloalkenes, benzene compounds, biphenyl compounds, and polyphenyl compounds) at T = 298.15 K. A total of 260 experimental standard molar enthalpies of vaporization at T = 298.15 K were used for the parameters optimization. Comparison between the experimental values and those calculated using ELBA led to an average absolute difference of 0.35 kJ mol-1, corresponding to an average relative error of 0.92%. In addition, this new method proves to be better than the ones used for comparison with an independent set of 83 experimental standard molar enthalpies of vaporization at T = 298.15 K.

Santos, Rui C.; Leal, Joa~o. P.

2012-12-01

431

The Role of Mandibular Third Molars on Lower Anterior Teeth Crowding and Relapse after Orthodontic Treatment: A Systematic Review  

PubMed Central

Aims. To evaluate the role of third molars in the development of crowding or relapse after orthodontic treatment in the anterior segment of the dental arch. Methods. PubMed search of the literature was performed selecting all the articles relevant to the topic and limiting the studies to controlled trials on humans and written in English language. Systematic review was conducted according to the PRISMA (preferred reporting items for systematic reviews and meta-analyses) statement. Results. A total of 12 clinical studies were included in the review. A high risk of bias was found in most of the articles, either because the relative items assessed were inadequate or because they were unclearly described. The third molars were not correlated with more severe anterior tooth crowding in most of the studies. However, four of them described a different outcome. Conclusion. Definitive conclusions on the role of the third molars in the development of anterior tooth crowding cannot be drawn. A high risk of bias was found in most of the trials, and the outcomes were not consistent. However, most of the studies do not support a cause-and-effect relationship; therefore, third molar extraction to prevent anterior tooth crowding or postorthodontic relapse is not justified.

Zawawi, Khalid H.

2014-01-01

432

Internal Resorption Treated with Mineral Trioxide Aggregate in a Primary Molar Tooth: 18Month Follow-Up  

Microsoft Academic Search

Mineral trioxide aggregate (MTA) repair of a mandibular second-primary molar tooth with an inflammatory resorptive defect in the coronal third of the root canal is reported in this case. After the root canals were obturated with zinc oxide eugenol sealer, MTA was applied to the resorption cavity. The coronal cavity was then restored with a stainless steel crown. At an

?aziye Sari; Deniz Sönmez

2006-01-01

433

Corneal Stromal Cell Growth on Gelatin/Chondroitin Sulfate Scaffolds Modified at Different NHS/EDC Molar Ratios  

PubMed Central

A nanoscale modification strategy that can incorporate chondroitin sulfate (CS) into the cross-linked porous gelatin materials has previously been proposed to give superior performance for designed corneal keratocyte scaffolds. The purpose of this work was to further investigate the influence of carbodiimide chemistry on the characteristics and biofunctionalities of gelatin/CS scaffolds treated with varying N-hydroxysuccinimide (NHS)/1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC) molar ratios (0–1) at a constant EDC concentration of 10 mM. Results of Fourier transform infrared spectroscopy and dimethylmethylene blue assays consistently indicated that when the NHS to EDC molar ratio exceeds a critical level (i.e., 0.5), the efficiency of carbodiimide-mediated biomaterial modification is significantly reduced. With the optimum NHS/EDC molar ratio of 0.5, chemical treatment could achieve relatively high CS content in the gelatin scaffolds, thereby enhancing the water content, glucose permeation, and fibronectin adsorption. Live/Dead assays and interleukin-6 mRNA expression analyses demonstrated that all the test samples have good cytocompatibility without causing toxicity and inflammation. In the molar ratio range of NHS to EDC from 0 to 0.5, the cell adhesion ratio and proliferation activity on the chemically modified samples significantly increased, which is attributed to the increasing CS content. Additionally, the materials with highest CS content (0.143 ± 0.007 nmol/10 mg scaffold) showed the greatest stimulatory effect on the biosynthetic activity of cultivated keratocytes. These findings suggest that a positive correlation is noticed between the NHS to EDC molar ratio and the CS content in the biopolymer matrices, thereby greatly affecting the corneal stromal cell growth.

Lai, Jui-Yang

2013-01-01

434

The determination of GC-MS relative molar responses of some n-alkanes and their halogenated analogs.  

PubMed

The dependence of relative response factors on the carbon atom number related to naphthalene has been investigated in homologous series by using gas chromatography-mass spectrometry. Relative responses of some straight chain aliphatic n-alkanes and their halogenated derivatives (chlorine, bromine and iodine) were compared in the experiments. Linear correlations were found between the molecular structures; i.e., the carbon atom number and relative molar response in current homologous series. In conclusion, mass spectrometric detection combined with gas chromatography was less sensitive to n-alkanes than to their derivatives containing a chlorine, bromine or iodine atom. After n-alkanes, mass spectrometric responses increase in the order of 1-chloroalkanes, 1-bromoalkanes and 1-iodoalkanes. These results are in accordance with electron ionization cross section data for n-alkyl-derivatives. The relative molar responses of the individual CH(2) groups are between 0.171 and 0.178 in the homologous series. The increments of chlorine, bromine and iodine atoms to the relative molar responses are 0.081, 0.141 and 0.492, respectively. Based on these results, the addivity rule is valid for both halogen atoms and CH(2) groups in the case of mono-substituted n-haloalkanes. The results of this study show a significant departure from the additivity rule in the case of polyhalogenated alkanes and alkenes. However, the relative molar response can be calculated by means of simultaneously measuring other compounds. Further study is needed about how to influence the relative molar responses as a function of various experimental parameters. PMID:22781184

Göröcs, Noémi; Mudri, Dénes; Mátyási, Judit; Balla, József

2013-02-01

435

Effects of the molar mass of the matrix on electrical properties, structure and morphology of plasticized PANI PMMA blends  

NASA Astrophysics Data System (ADS)

The effects of the molar mass of polymethylmethacrylate (PMMA) on electrical, structural and morphological properties of conductive polyaniline-polymethylmethacrylate blends have been studied. We have plasticized the PMMA matrix by using dioctyl phthalate (DioPh). Three different molar masses of PMMA, 15 000, 120 000 and 350 000 g mol-1, have been used. The x-ray diffraction analysis showed amorphous structure for all our studied PANI-PMMA blend films. The SEM micrographs showed more aggregation with the lowest molar mass of PMMA matrix. The direct current (dc) and alternating current (ac) electrical conductivities have been investigated in the temperature range 20-300 K and frequency range 7-1 × 108 Hz. The results of this study indicate an increase of the conductivity when the molar mass of PMMA decreases. With the lowest molar mass of PMMA (15 000 g mol-1), we obtained the lowest percolation threshold (pc?0.3%). The dc conductivity is governed by Mott's three-dimensional variable range hopping (3D VRH) model; different Mott's parameters have been evaluated. At high frequencies, the ac conductivity follows the power law ?(?,T) = A(T)?s(T,?), which is characteristic for charge transport in disordered materials by hopping or tunnelling processes. The observed decrease in the frequency exponent s with increasing temperature suggests that the correlated barrier hopping (CBH) model best describes the ac conduction mechanism. All our blends are well described by the scaling law ?(?)/?dc = 1+(?/?c)n with n?0.51-0.52.

Gmati, Fethi; Fattoum, Arbi; Bohli, Nadra; Belhadj Mohamed, Abdellatif

2008-03-01

436

Molar gas ratios of air entrapped in ice: A new tool to determine the origin of relict massive ground ice bodies in permafrost  

Microsoft Academic Search

The molar ratios of atmospheric gases change during dissolution in water due to differences in their relative solubilities. We exploited this characteristic to develop a tool to clarify the origin of ice formations in permafrost regions. Extracted from ice, molar gas ratios can distinguish buried glacier ice from intrasedimental ground ice formed by freezing groundwaters. An extraction line was built

Raphaelle Cardyn; Ian D. Clark; Denis Lacelle; Bernard Lauriol; Christian Zdanowicz; Fabrice Calmels

2007-01-01

437

Rheological evaluation of the influence of polymer concentration and molar mass distribution on the formation and performance of asymmetric gas separation membranes prepared by dry phase inversion  

Microsoft Academic Search

Asymmetric gas separation membranes were prepared by the dry-casting technique from PEEKWC, a modified amorphous glassy poly(ether ether ketone). The phase inversion process and membrane performance were correlated to the properties of the polymer and the casting solution (molar mass, polymer concentration, solution rheology and thermodynamics). It was found that a broad molar mass distribution of the polymer in the

Johannes C. Jansen; Marialuigia Macchione; Cesare Oliviero; Raniero Mendichi; Giuseppe A. Ranieri; Enrico Drioli

2005-01-01