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1

Molarity  

NSDL National Science Digital Library

What determines the concentration of a solution? Learn about the relationships between moles, liters, and molarity by adjusting the amount of solute and solution volume. Change solutes to compare different chemical compounds in water.

Simulations, Phet I.; Chamberlain, Julia; Malley, Chris; Lancaster, Kelly; Parson, Robert; Perkins, Kathy

2012-02-20

2

Intraoperative molar pregnancy crisis.  

PubMed

Molar pregnancy is a gestation in which the ovum is transformed into a fleshy tumor mass or mole. Of all gynecologic tumors, it is one of the most feared. It is characterized by first trimester bleeding, hyperemesis, and toxemia and can be diagnosed using pelvic ultrasound. Suction currettage is the treatment of choice for molar pregnancy when a patient desires to have more children; however, hysterectomy may be necessary. Abdominal hysterectomy reduces the risk of malignant sequelae. Complications associated with molar pregnancy usually are a result of suction curettage and include pulmonary insufficiency syndrome, choriocarcinoma, hyperthyroidism, theca lutein cysts, and disseminated intravascular coagulation. The perioperative nurse can be instrumental in assessing, planning, organizing, and directing intervention for potential complications associated with the management of a molar pregnancy crisis. The perioperative nurse is encouraged to review all aspects of molar pregnancy to understand the ramifications of the surgical procedures. PMID:7944318

Robinson, B J

1994-08-01

3

The formation and evolution of Hule and Río Cuarto maars, Costa Rica  

NASA Astrophysics Data System (ADS)

The Hule and Río Cuarto maars are respectively located 11 and 18 km northward of the active crater of Poás volcano, on the Caribbean side of the Central Volcanic Range of Costa Rica. They lie on the northern part of Poás volcano massif, along a N-S trending, ~ 27 km-long volcanic fracture crossing the Poás volcano. The volcanic products from Hule maar (2.3 km × 1.8 km, area ~ 3.5 km 2) are mainly pyroclastic surges (poorly vesiculated andesites with very small plagioclases), silica-rich andesitic pumice flows, air-fall deposits, ballistic blocks, and reworked deposits that overlie the regional Pleistocene volcanic basement. They were produced during three main explosive phases. Two overlapping pyroclastic cones have developed within the Hule maar, and at least three lava fields are related to them (high-Al basalt to basaltic andesite). Another maar, Pata de Gallo (400 m across), is located less than 1 km off the SE rim of Hule. Río Cuarto is a nearly circular maar (700-850 m across) with a surface area of 0.33 km 2. Río Cuarto products include surges, ballistics and air-fall tephra, produced during three main explosive phases. These deposits show a narrow fan oriented westward, according to westerly wind direction. They indicate a westerly-directed surge (first 2 km), followed by air-fall deposits (up to 5 km away). Radiocarbon dating has shown that Hule was formed ~ 6.2 ka ago and Pata de Gallo probably formed ~ 2.8 ka ago, while the intra-maar products could have ages of ~ 1.7 ka or ~ 0.7 ka, indicating that Hule is a polygenetic maar. There are no radiocarbon ages yet for dating the formation of Río Cuarto maar, but archaeological data suggest that it erupted between 3-4 ka ago. The volume of pyroclastic deposits associated to Hule maar is estimated to be 0.51-0.53 km 3, from which ~ 20% is juvenile material, therefore 0.07-0.08 km 3 of new dense rock equivalent (DRE) magma, after subtracting 20-30% of porosity. The tephra from Río Cuarto is estimated to be 4.4 × 10 7 m 3, of which 0.008 m 3 correspond to DRE magma. The Hule and Río Cuarto maars are occupied by lakes and, in the last decades, several lake-overturn events have taken place, with a repeat cycle of six to seven years. The main outcome of these events has been the mass death of fish accompanied by changes in the lake color. In these systems, the hazard related to the possible occurrence of Nyos-type gas eruptions can be considered negligible or very local, but significant for tourists who camp by the lakes.

Alvarado, Guillermo E.; Soto, Gerardo J.; Salani, Flavia M.; Ruiz, Pablo; de Mendoza, Luis Hurtado

2011-04-01

4

Molarization of Mandibular Second Premolar  

PubMed Central

ABSTRACT Macrodontia (megadontia, megalodontia, mac rodontism) is a rare shape anomaly that has been used to describe dental gigantism. Mandibular second premolars show an elevated variability of crown morphology, as are its eruptive potential and final position in the dental arch. To date, only eight cases of isolated macrodontia of second premolars have been reported in the literature. This case report presents clinical and radiographic findings of unusual and rare case of isolated unilateral molarization of left mandibular second premolar. How to cite this article: Mangla N, Khinda VIS, Kallar S, Brar GS. Molarization of Mandibular Second Premolar. Int J Clin Pediatr Dent 2014;7(2):137-139. PMID:25356014

Singh Khinda, Vineet Inder; Kallar, Shiminder; Singh Brar, Gurlal

2014-01-01

5

Molar versus as a paradigm clash.  

PubMed Central

The molar view of behavior arose in response to the demonstrated inadequacy of explanations based on contiguity. Although Dinsmoor's (2001) modifications to two-factor theory render it irrefutable, a more basic criticism arises when we see that the molar and molecular views differ paradigmatically. The molar view has proven more productive. PMID:11453623

Baum, W M

2001-01-01

6

[On eruption of mandibular third molar after extraction of mandibular first or second molar].  

PubMed

In the orthodontic practice, the first or second molars are extracted by reason of a necessity based on the treatment planning. In these cases, it is desirable that the third molar would be taken part in the masticatory function. This study was made to investigate the natural movement of the erupting third molars after the extraction of the first or second molar on the serial lateral cephalometric radiographs and orthopantomographs. Subjects were divided into three groups. The first is the group which the mandibular second molars were extracted. The second is the group which the first molars were extracted bringing about the successful eruption of the third molars. The third is the group which the first molars were extracted with resultant in the failure of the third molar eruption. In all cases, the orthodontic forces were not applied to the third molars. The results were as follows: 1. In the first group, all third molars were successfully erupted and a lot of the spaces after the extraction of second molars were utilized for the eruption of third molars. 2. In the second group, all third molars were successfully erupted and a lot of the spaces after the extraction of first molars were utilized for the mesial movement of the second molars. 3. In the third group, there were various patterns of the impaction of the third molars. It was suggested that the eruption of the third molar was related to the space distal to the second molar but it was not related to the anterio-posterior length of the mandibular body significantly. PMID:2133887

Yamabe, K; Kouguchi, M; Watanabe, Y; Yamauchi, K

1990-08-01

7

Prevalence and Pattern of Third Molar Impaction  

PubMed Central

Objectives: The aim of this retrospective study was to investigate the prevalence and pattern of third molar impaction in patients between 19–26 years old attending Sultan Qaboos University Hospital (SQUH) in Muscat, Oman. Methods: The study reviewed 1,000 orthopantomograms (OPGs) of patients attending the Oral Health Department of SQUH between October 2010 and April 2011. Patients were evaluated to determine the prevalence of third molar impaction, angulation, level of eruption and associated pathological conditions. Results: Of the study population, 543 (54.3%) OPGs showed at least one impacted third molar. The total number of impacted molars was 1,128. The most common number of impacted third molars was two (41%). The most common angulation of impaction in the mandible was the mesioangular (35%) and the most common level of impaction in the mandible was level A. Of the 388 bilateral occurrences of impacted third molars, 377 were in the mandible. There was no significant difference in the frequency of impaction between the right and left sides of both jaws. Pathological conditions associated with impacted lower third molars were found in 18%, of which 14% were associated with a radiographic radiolucency of more than 2.5 mm, and 4% of impacted lower third molars were associated with dental caries. Conclusion: This study found that more than half of Omani adult patients ranging in age from 19–26 years had at least one impacted third molar. PMID:25097776

Al-Anqudi, Samira M.; Al-Sudairy, Salim; Al-Hosni, Ahmed; Al-Maniri, Abdullah

2014-01-01

8

Molar Malocclusions in Pine Voles (Microtus pinetorum)  

PubMed Central

Here we describe 5 cases of molar malocclusions in adult pine voles (Microtus pinetorum) used for behavioral endocrinology studies. This species belongs to the subfamily Microtinae, which possess aradicular hypsodont molars. The abnormal molars identified caused apparent difficulty in mastication, resulting in poor body condition necessitating euthanasia. Postmortem examination of the oral cavity revealed grossly elongated mandibular and maxillary molars with abnormal wear at occlusal surfaces. This colony health problem was addressed successfully by adding autoclaved hardwood sticks to each cage as an enrichment tool. PMID:19653952

Harvey, Stephen B; Alworth, Leanne C; Blas-Machado, Uriel

2009-01-01

9

Immature primary molar in the newborn  

Microsoft Academic Search

A clinical report of an erupted immature primary molar in a newborn is presented. The occurrence of a natal or neonatal molar can be considered a rare event since the majority of cases described are incisors. Clinical appearance, location, histological and radiographical examinations were used to establish the identity oF the lesion, The literature related to natal and neonatal teeth

Stephen K Brandt; Steven D. Shapiro; Paul E. Kittle

1983-01-01

10

Expressly Fabricated Molar Tube Bases: Enhanced Adhesion  

PubMed Central

Clinicians, Orthodontists and their patients’ parents often expect the best results in the shortest time span possible. Orthodontic bonding of molar tubes has been an acceptable risk in a modern era of refined biomaterials and instrumentation. Although many orthodontists still prefer banding to bonding, it is the failure rate of the tubes on molars which accounts to an impedance in molar bonding. One of the reasons for molar attachment failures is attributed to improper adaptation of the buccal tube base with or without increased thickness of composite. Merits of banding the second molars especially when these are the terminal teeth for anchorage have been overemphasized in the literature. The present article presents a simple and relatively less time consuming technique of preparing molar tubes to be bonded on tooth surfaces which may be quite difficult to isolate especially for bonding, for example, mandibular second molars. The increased surface area of the composite scaffold helps not only in enhanced bond strength but also serves to reduce the incidence of plaque accumulation given the dexterity of invitro preparation. The removal of the occlusal part of the molar tube scaffold helps in prevention of open / raised bite tendencies. The present innovation, therefore, is not merely serendipity but a structured technique to overcome a common dilemma for the clinical orthodontist. The present dictum of banding being superior to molar tube bonding may prove to be futile with trendsetting molar attachments. It is also an established fact that bonding proves to be a lesser expensive modality when compared to banding procedures. PMID:25121070

Phull, Tarun Singh; Rana, Tarun; Kumar, Varun

2014-01-01

11

Antibiotics in third molar surgery.  

PubMed

The aim of this survey was to assess the knowledge and practice of Swiss dentists focusing on the use of antibiotics in prophylactic surgical removal of lower wisdom teeth. A postal survey was conducted among all 3288 dentists who are members of the Swiss Dental Society (SSO) representing nearly all dentists in Switzerland. The questionnaire consisted of 13 questions with mostly multiple-choice answers. Demographic profile, surgical experience, the use of antibiotics, and wound management, i.e. wound closure and the use of mouth rinse were assessed. A response rate of 55% was obtained. Most Swiss dentists perform surgical extractions in their practices. Of all dentists, 18.6% used antibiotics routinely, but a large variation was found comparing the three linguistic regions of Switzerland with the highest prescription rate of 48% in the French-speaking south-west of Switzerland. Fifty-two percent of dentists prescribed amoxicillin in a dose of 750 mg. Most often three daily doses were prescribed (47%). A postoperative regime was prescribed by 54.4% of dentists. French language (p=0.003), graduation from the university of Geneva (p=0.007), foreign diplomas (p<0.001), and dentists with diplomas awarded from 2001-2006 (p=0.004) showed a highly significant correlation with the use of antibiotics. In Switzerland, prophylactic antibiotics are used in third molar surgery. Antibiotic prescription however largely depends on geographical situation and dentist profiles. The assessment of antibiotic use in private practices is important in the light of growing evidence that antibiotic overuse may lead to development of multiresistant bacterial strains. In a second part results regarding wound management and mouth rinse will be presented. PMID:24671748

Vlcek, Daniel; Razavi, Amir; Kuttenberger, Johannes J

2014-01-01

12

Apparent Molar Volume and Apparent Molar Expansibility of Rubidium, Cesium, and Ammonium Cyclohexylsulfamate in Aqueous Solution  

Microsoft Academic Search

Summary.  The apparent molar volume of rubidium, caesium, and ammonium cyclohexylsulfamate was determined from the density data of their\\u000a aqueous solutions at 293.15, 298.15, 303.15, 313.15, 323.15, and 333.15?K. From the apparent molar volume, determined at various\\u000a temperatures, the apparent molar expansibility was calculated. The limiting apparent molar volume and apparent molar expansibility\\u000a were evaluated and apportioned into their ionic components.

Cveto Klofutar; Jaka Horvat; Darja Rudan-Tasic

2006-01-01

13

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. PMID:23320203

Prasad, M. Bhanu; Sreevalli, S.

2012-01-01

14

Molars and incisors: show your microarray IDs  

PubMed Central

Background One of the key questions in developmental biology is how, from a relatively small number of conserved signaling pathways, is it possible to generate organs displaying a wide range of shapes, tissue organization, and function. The dentition and its distinct specific tooth types represent a valuable system to address the issues of differential molecular signatures. To identify such signatures, we performed a comparative transcriptomic analysis of developing murine lower incisors, mandibular molars and maxillary molars at the developmental cap stage (E14.5). Results 231 genes were identified as being differentially expressed between mandibular incisors and molars, with a fold change higher than 2 and a false discovery rate lower than 0.1, whereas only 96 genes were discovered as being differentially expressed between mandibular and maxillary molars. Numerous genes belonging to specific signaling pathways (the Hedgehog, Notch, Wnt, FGF, TGF?/BMP, and retinoic acid pathways), and/or to the homeobox gene superfamily, were also uncovered when a less stringent fold change threshold was used. Differential expressions for 10 out of 12 (mandibular incisors versus molars) and 9 out of 10 selected genes were confirmed by quantitative reverse transcription-PCR (qRT-PCR). A bioinformatics tool (Ingenuity Pathway Analysis) used to analyze biological functions and pathways on the group of incisor versus molar differentially expressed genes revealed that 143 genes belonged to 9 networks with intermolecular connections. Networks with the highest significance scores were centered on the TNF/NF?B complex and the ERK1/2 kinases. Two networks ERK1/2 kinases and tretinoin were involved in differential molar morphogenesis. Conclusion These data allowed us to build several regulatory networks that may distinguish incisor versus molar identity, and may be useful for further investigations of these tooth-specific ontogenetic programs. These programs may be dysregulated in transgenic animal models and related human diseases leading to dental anomalies. PMID:23531410

2013-01-01

15

Efficiency of a pendulum appliance for molar distalization related to second and third molar eruption stage  

Microsoft Academic Search

A modified pendulum appliance, including a distal screw and special preactivated pendulum springs (built-in straightening activation and toe-in bending), was used for bilateral maxillary molar distalization in 36 adolescent patients in various stages of the molar dentition. The patients were divided into 3 groups (PG 1-3) according to the stage of eruption of their second and third molars. In PG

Gero S. M Kinzinger; Ulrike B Fritz; Franz-Günter Sander; Peter R Diedrich

2004-01-01

16

Orthodontic extrusion of horizontally impacted mandibular molars  

PubMed Central

Objective: To introduce and evaluate a novel approach in treating horizontally impacted mandibular second and third molars. Materials and methods: An orthodontic technique was applied for treatment of horizontally impacted mandibular second and third molars, which included a push-type spring for rotation first, and then a cantilever for extrusion. There were 8 mandibular third molars (M3s) and 2 second molars (M2s) in this study. Tooth mobility, extraction time, the inclination and parallelism of the impacted tooth, alveolar bone height of the adjacent tooth, and the relationship of impacted M3 and the inferior alveolar nerve (IAN) were evaluated. Results: Two horizontally impacted M2s could be upright in the arch and good occlusal relationships were obtained after treatment. All impacted M3s were successfully separated from the IAN, without any neurologic consequences. The average extraction time was 5 minutes. There was a significant change in the inclination and parallelism of the impacted tooth after treatment. A new bone apposition with the average height of 3.2 mm was noted distal to the adjacent tooth. Conclusions: This two-step orthodontic technique as presented here may be a safe and feasible alternative in management of severely horizontally impacted mandibular molars, which achieves a successful separation of M3s from the IAN and an excellent position for M2s.

Ma, Zhigui; Yang, Chi; Zhang, Shanyong; Xie, Qianyang; Shen, Yuqing; Shen, Pei

2014-01-01

17

Oxygen from Hydrogen Peroxide. A Safe Molar Volume-Molar Mass Experiment.  

ERIC Educational Resources Information Center

Describes a molar volume-molar mass experiment for use in general chemistry laboratories. Gives background technical information, procedures for the titration of aqueous hydrogen peroxide with standard potassium permanganate and catalytic decomposition of hydrogen peroxide to produce oxygen, and a discussion of the results obtained in three…

Bedenbaugh, John H.; And Others

1988-01-01

18

Molar and Modular Examples 1 Running head: ENHANCING LEARNING FROM MOLAR AND MODULAR  

E-print Network

that are to be integrated into a to-be- learned schema and therefore have to be processed in working memory s Gerjets, P., Scheiter, K., & Catrambone, R. (2006). Can learning from molar and modular worked examples © Elsevier Ltd. 2006. doi:10.1016/j.learninstruc.2006.02.007 Can Learning from Molar and Modular Worked

Paris-Sud XI, Université de

19

The Neanderthalian molar from Hunas, Germany.  

PubMed

In this paper, we present a well-preserved isolated human molar found in 1986 in the Hunas cave ruin, south-east Bavaria. The tooth was located at the bottom of layer F2, which belongs to a long stratigraphic sequence comprising faunal remains as well as archaeological levels (Mousterian). A stalagmite from layer P at the base of the stratigraphic sequence was recently dated to 79.373+/-8.237 ka (base) and 76.872+/-9.686 ka (tip) by TIMS-U/Th (Stanford University). We identified the tooth as a right (possibly third) mandibular molar. Characteristic parameters such as crown and root morphology, fissure pattern, enamel thickness, occlusal and interproximal wear, dental dimensions and indices, and radiological features indicate that the Hunas molar represents the tooth of a Neanderthal. This is corroborated by both the palaeontological and archaeological findings (Mousterian) of layer F2. PMID:16780842

Alt, K W; Kaulich, B; Reisch, L; Vogel, H; Rosendahl, W

2006-01-01

20

Prevalence of asymmetric molar and canine relationship.  

PubMed

The purpose of this study was to investigate the prevalence and severity of occlusal asymmetries in the molar and canine regions in a large population-based sample of adolescent Kuwaitis. Using a stratified cluster sampling method, 1299 Kuwaiti adolescents (674 boys mean age 13.3 years and 625 girls mean age 13.2 years), representing approximately 6.7 per cent of that age stratum in the population, were examined clinically for sagittal molar and canine relationships, with a view to recording half and full-step asymmetries. In this sample, 1244 subjects were examined clinically, while for the remaining 55, pre-treatment study models were assessed. All subjects were in the early permanent dentition stage. Descriptive statistical analyses were used to determine the proportion of different molar and canine asymmetries. Antero-posterior asymmetries were found to be a distinctive and common feature of the dental arches, with half-step outweighing full-step asymmetries both in the anterior and posterior regions. The total prevalence of an asymmetric molar or canine relationship was 29.7 and 41.4 per cent, respectively, with more than 95 per cent falling in the mild category. Patient gender did not influence the prevalence or magnitude of asymmetry. The results showed a clinically significant prevalence of asymmetric molar and canine relationships, which were mainly in the category of half-step asymmetry. Class II half and full-step asymmetries were more prevalent than Class III asymmetries in the molar and canine regions. PMID:21742643

Behbehani, Faraj; Roy, Rino; Al-Jame, Badreia

2012-12-01

21

Geosphere-biosphere interactions in bio-activity volcanic lakes: evidences from Hule and Rìo Cuarto (Costa Rica).  

PubMed

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). PMID:25058537

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

22

Apparent Molar Volume and Apparent Molar Expansibility of Lithium, Sodium, Potassium, and Tetramethylammonium Cyclohexylsulfamate in Aqueous Solution  

Microsoft Academic Search

Summary. The apparent molar volume of lithium, sodium, potassium, and tetramethylammonium cyclohexylsulfamate was determined from the density data of their aqueous solutions at 293.15, 298.15, 303.15, 313.15, and 323.15?K. The apparent molar expansibility was calculated from the apparent molar volume at various temperatures. The limiting apparent molar volume and apparent molar expansibility were evaluated and divided into their ionic components.

Cveto Klofutar; Darja Rudan-Tasic

2005-01-01

23

The Neanderthalian molar from Hunas, Germany  

Microsoft Academic Search

In this paper, we present a well-preserved isolated human molar found in 1986 in the Hunas cave ruin, south-east Bavaria. The tooth was located at the bottom of layer F2, which belongs to a long stratigraphic sequence comprising faunal remains as well as archaeological levels (Mousterian). A stalagmite from layer P at the base of the stratigraphic sequence was recently

K. W. Alt; L. Reisch; H. Vogel; W. Rosendahl

2006-01-01

24

Continuous multi-criteria methods for crop and soil conservation planning on La Colacha (Río Cuarto, Province of Córdoba, Argentina)  

NASA Astrophysics Data System (ADS)

Agro-areas of Arroyos Menores (La Colacha) west and south of Río Cuarto (Prov. of Córdoba, Argentina) basins are very fertile but have high soil loses. Extreme rain events, inundations and other severe erosions forming gullies demand urgently actions in this area to avoid soil degradation and erosion supporting good levels of agro production. The authors first improved hydrologic data on La Colacha, evaluated the systems of soil uses and actions that could be recommended considering the relevant aspects of the study area and applied decision support systems (DSS) with mathematic tools for planning of defences and uses of soils in these areas. These were conducted here using multi-criteria models, in multi-criteria decision making (MCDM); first of discrete MCDM to chose among global types of use of soils, and then of continuous MCDM to evaluate and optimize combined actions, including repartition of soil use and the necessary levels of works for soil conservation and for hydraulic management to conserve against erosion these basins. Relatively global solutions for La Colacha area have been defined and were optimised by Linear Programming in Goal Programming forms that are presented as Weighted or Lexicographic Goal Programming and as Compromise Programming. The decision methods used are described, indicating algorithms used, and examples for some representative scenarios on La Colacha area are given.

Antón, J. M.; Grau, J. B.; Cisneros, J. M.; Laguna, F. V.; Aguado, P. L.; Cantero, J. J.; Andina, D.; Sánchez, E.

2012-08-01

25

4. New perspectives on chimpanzee and human molar crown development  

E-print Network

within humans. Within upper molars, mesiopalatal cusps (protocones) show thicker cuspal enamel and longer crown formation time than mesiobuccal cusps (paracones). Within lower molars, mesiobuccal cusps4. New perspectives on chimpanzee and human molar crown development T.M. SMITH Human Evolution

Smith, Tanya M.

26

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. PMID:24949012

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

2014-01-01

27

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. PMID:25071882

Nakamori, Kenji; Tomihara, Kei; Noguchi, Makoto

2014-01-01

28

Adjacent dentigerous cysts with the ectopic displacement of a third mandibular molar and supernumerary (forth) molar: a rare occurrence.  

PubMed

Dentigerous cysts are the most common odontological cysts of the jaws, being associated with the crowns of permanent teeth, especially unerupted mandibular third molars. Multiple dentigerous cysts are rare and most often occur in association with a developmental syndrome. This article presents an unusual case of nonsyndromic adjacent dentigerous cysts associated with a mandibular third molar and a supernumerary molar. This occurrence has not been previously reported. PMID:19464637

McCrea, Shane

2009-06-01

29

Clinical decision making on extensive molar restorations.  

PubMed

SUMMARY Extensive loss of posterior tooth substance, which traditionally was restored with amalgam or indirect restorations, is more commonly being restored with resin-based composite restorations. Using a questionnaire, we aimed to survey dentists' clinical decision making when restoring extensive defects in posterior molar teeth. The questionnaire, which included questions on background information from the dentists, clinical cases with treatment options, and general questions about restoring extensive posterior defects, was sent to 476 dentists. The response rate was 59%. Multiple logistic regressions were used to investigate the different associations. Most of the respondents preferred a direct composite restoration when one cusp was missing, while indirect restorations were most preferred when replacing three or four cusps. Younger dentists and dentists working in the private sector had a greater tendency to choose an indirect technique compared with older colleagues. Generally, the most important influencing factor in clinical decision making was the amount of remaining tooth substance. Factors that appeared to be less important were dental advertisements, use of fluoride, and dietary habits. Female dentists perceived factors such as oral hygiene, patient requests, and economy to be more important than did their male colleagues. PMID:24828135

Laegreid, T; Gjerdet, Nr; Johansson, A; Johansson, A-K

2014-01-01

30

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

31

Modification of uprighting spring for derotation of second molars.  

PubMed

One of the most efficient ways for the correction of rotated upper molars is derotation with a transpalatal arch, but this appliance is usually favourable when the need for correction is same on both sides of the dental arch. Derotation of unilateral upper second molar is a difficult task, especially when there is no accessible tooth/ any attachment is available distal to it for the application of couple forces. We have designed a modification of uprighting spring which is far more convenient than using the conventional method of TPA for derotation of unilateral upper second molar. PMID:24640073

Mallikarjun, Vankre; Rachala, Madhukar Reddy; Aileni, Kaladhar Reddy; Jaipal, Pyata Reddy

2013-01-01

32

Orthognathic treatment with autotransplantation of a third molar.  

PubMed

Autotransplantation is an option for tooth replacement when a suitable tooth is available and anatomic circumstances are favorable. This case report describes successful orthognathic treatment that was combined with autotransplantation of a maxillary third molar. A 20-year-old woman had mandibular protrusion and facial asymmetry. Five years previously, her mandibular right first molar had been extracted because of dental caries. After preoperative orthodontic treatment, we performed a LeFort I procedure and a bilateral intraoral vertical ramus osteotomy to correct the patient's mandibular protrusion and facial asymmetry. During the postoperative orthodontic treatment, the maxillary left third molar was autotransplanted into the mandibular right first molar site. The total treatment period was 24 months. As a result of these therapeutic treatments, the patient's facial appearance was improved, and an implant was unnecessary. The autotransplanted tooth effectively supported the adjacent teeth and maintained her chewing ability. PMID:24182590

Choi, Sung-Hwan; Hwang, Chung-Ju

2013-11-01

33

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

34

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

35

40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.  

Code of Federal Regulations, 2011 CFR

...false SSV, CFV, and PDP molar flow rate calculations. 1065...PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING...642 SSV, CFV, and PDP molar flow rate calculations. This section...equations for calculating molar flow rates from various flow...

2011-07-01

36

40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.  

Code of Federal Regulations, 2012 CFR

...false SSV, CFV, and PDP molar flow rate calculations. 1065...PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING...642 SSV, CFV, and PDP molar flow rate calculations. This section...equations for calculating molar flow rates from various flow...

2012-07-01

37

40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.  

Code of Federal Regulations, 2010 CFR

...false SSV, CFV, and PDP molar flow rate calculations. 1065...PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING...642 SSV, CFV, and PDP molar flow rate calculations. This section...equations for calculating molar flow rates from various flow...

2010-07-01

38

40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.  

Code of Federal Regulations, 2013 CFR

...false SSV, CFV, and PDP molar flow rate calculations. 1065...PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING...642 SSV, CFV, and PDP molar flow rate calculations. This section...equations for calculating molar flow rates from various flow...

2013-07-01

39

Preliminary Evaluation of Sodium Hypochlorite for Pulpotomies in Primary Molars  

Microsoft Academic Search

Purpose: The purpose of this study was to compare the effectiveness of 5% sodium hypo- chlorite (NaOCl) to that of ferric sulfate (FeSO4) as a pulpotomy medicament in decayed primary molars. Methods: Healthy subjects between 4 and 9 years with at least 2 primary molars need- ing pulpotomy consented to receive either NaOCl or FeSO4 and restoration with IRM base\\/stainless

Kaaren G. Vargas; Brett Packham; David Lowman

2006-01-01

40

Partial molar quantity of an intensive mother function.  

PubMed

A new formal definition is given to the partial molar quantity of a component i for an intensive mother function. We perturb the entire system by increasing the amount of the target component by ?n(i) keeping others constant and measure the response of the system in terms of an intensive mother function, ?, ??. We then define its partial molar quantity of the ith component, ?(i), as ?(i) = [???{?n(i)?(N + ?n(i))

Koga, Yoshikata

2012-09-28

41

Prevalence of missing and impacted third molars in adults aged 25 years and above  

PubMed Central

Purpose The purpose of this study was to determine the prevalence of missing and impacted third molars in people aged 25 years and above. Materials and Methods The study sample of 3,799 patients was chosen randomly from patients who visited Pusan National University Dental Hospital and had panoramic radiographs taken. The data collected included presence and impaction state, angulation, and depth of impaction of third molars, and radiographically detected lesions of third molars and adjacent second molars. Results A greater percentage of men than women retained at least one third molar. The incidence of third molars decreased with increasing age. The incidence of partially impacted third molars greatly declined after the age of 30. Vertically impacted maxillary third molars and horizontally impacted mandibular third molars were most frequent in all age groups. Among the maxillary third molars, those impacted below the cervical line of the second molar were most frequent in all age groups, and among the mandibular third molars, deeply impacted third molars were most frequent in those aged over 40. Dental caries was the most common radiographic lesion of the third molars. Mesioangularly impacted third molars showed radiographic lesions in 13 (9.5%) adjacent maxillary second molars and 117 (27.4%) mandibular second molars. Conclusion The number of remaining third molars decreased and the percentage of Class C depth increased with age. Caries was the most frequent lesion in third molars. Partially impacted mesioangular third molars showed a high incidence of caries or periodontal bone loss of the adjacent second molar. Regular oral examination will be essential to keep asymptomatic third molars in good health. PMID:24380060

Jung, Yun-Hoa

2013-01-01

42

First permanent molar root development arrest associated with compound odontoma.  

PubMed

Trauma or infection to the primary tooth may have deleterious effects on the underlying developing tooth buds. Anatomically the root apices of primary teeth are in close proximity to the developing permanent tooth buds; hence spread of infection originating from pulp necrosis of primary tooth may not only affect the underlying tooth bud but may also affect the adjacent tooth buds. The extent of malformation depends on the developmental stage of tooth or the age of patient. Presented here is a rare case of complete arrest of maxillary first permanent molar root growth due to spread of periapical infection originating from second primary molar leading to failure of its eruption and finally extraction. Histopathlogical analysis revealed compound odontoma associated with maxillary first permanent molar. PMID:23832997

Gunda, Sachin A; Patil, Anil; Varekar, Aniruddha

2013-01-01

43

- and Low-Molar Liquid Crystal Mixtures for Photorefractive Applications  

NASA Astrophysics Data System (ADS)

We describe a highly efficient photorefractive material possessing high-molar-mass liquid crystal (H-LC), low-molar-mass liquid crystal (L-LC), and photoconductive agent. These photorefractive high- and low-molar-mass liquid crystal mixtures (HL-LCMs) show high-performance in a thick grating regime (Bragg regime) under low dc electric fields (< 1 V/?m). The photorefractive properties are strongly dependent on the concentration of the H-LC. The fastest response time of 70 ms is achieved with a gain coefficient of 213 cm-1 in the case of 10 wt% of the H-LC with 0.18 V/?m. The largest gain coefficient of over 600 cm-1 is achieved with the response time of 2.6 s in the case of 40 wt% of the H-LC with 0.7 V/?m. In addition, our future directions in this research area are also presented.

Ono, Hiroshi; Kawatsuki, Nobuhiro

44

Anxiety and extraction of third molars in Turkish patients.  

PubMed

Preoperative anxiety is widespread and adversely affects a patient's physical and psychological outcome. Extraction of third molars is common, and many patients complain of anxiety and emotional disturbance. We assessed the anxiety of patients in Turkey before extraction of third molars. A total of 120 patients were admitted for removal of one or more third molars under local anaesthesia. The Amsterdam Preoperative Anxiety and Information Scale (APAIS) and Spielberger's State Trait Anxiety Inventory (STAI) were used to evaluate anxiety. The results showed that women were significantly more anxious than men; women who had not had a previous operation were more anxious than other women; there was no difference in the anxiety scores of patients who had previously had a local anaesthetic and those who had not; there were no differences in anxiety as measured by trait scores; patients who wanted a lot of information were more anxious. PMID:15544887

Garip, Hasan; Abali, Osman; Göker, Kamil; Göktürk, Ulkü; Garip, Yildiz

2004-12-01

45

Paramolar - A supernumerary molar: A case report and an overview  

PubMed Central

Paramolar is a supernumerary molar usually small and rudimentary, most commonly situated buccally or palatally to one of the maxillary molars. Paramolar is a developmental anomaly and has been argued to arise from a combination of genetic and environmental factors. Reports of this entity are rarely found in the dental literature. This article presents a case report of an unusual occurrence of a paramolar in the maxilla in otherwise a healthy individual. In addition, literature review, prevalence, classification, etiology, complications, diagnosis, and therapeutic strategies that may be adopted when supernumeraries occurs have been discussed. PMID:23559961

Nayak, Gurudutt; Shetty, Shashit; Singh, Inderpreet; Pitalia, Deepti

2012-01-01

46

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. PMID:25050182

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

2014-01-01

47

Inflammatory root resorption in primary molars: prevalence and associated factors.  

PubMed

This study aimed at determining the prevalence of inflammatory root resorption and associated factors in 1068 primary mandibular molars in 453 children 3 to 12 years of age. Age, dental history and medical history were recorded using a questionnaire administered to the children's parents/caregivers. Previously trained and calibrated examiners assessed radiographic images of the primary molars by direct observation, with the aid of a viewing box. Root resorption (physiological or inflammatory), dental crown status (healthy, carious with no pulp involvement, carious with pulp involvement and evidence of restoration), and pulpotomy or pulpectomy were determined. Data analysis involved descriptive statistics, the chi-square test and a multiple logistic regression (p < 0.05). The prevalence of inflammatory root resorption was 16.2% (n = 173). The male gender (OR: 1.4; 95% CI), the 3-to-7-years age bracket (OR: 1.5; 95% CI), an unhealthy dental crown (OR: 8.7; 95% CI), caries with pulp involvement (OR: 7.4; 95% CI), pulpotomy (OR: 3.1; 95% CI), and pulpectomy (OR: 5.4; 95% CI) were risk factors for the occurrence of inflammatory root resorption in primary molars. In conclusion, the prevalence of inflammatory root resorption in the present sample was 16.2%. Gender, age, an unhealthy tooth, caries with pulp involvement, pulpotomy, pulpectomy, and the absence of a restoration were associated with a higher occurrence of inflammatory root resorption in primary molars. PMID:22790498

Vieira-Andrade, Raquel Gonçalves; Drumond, Clarissa Lopes; Alves, Laura Pereira Azevedo; Marques, Leandro Silva; Ramos-Jorge, Maria Letícia

2012-01-01

48

On the apparent molar volumes of nonelectrolytes in water  

Microsoft Academic Search

Apparent molar volumes of aqueous solutions of argon and xenon have been calculated using a previously developed comprehensive equation of state for nonelectrolyte systems. The equation consists of a virial expansion truncated after the fourth virial coefficient and a closed-form term approximating higher coefficients. Mixing rules are based on the composition dependence of virial coefficients, which is known from statistical

Andrzej Anderko; John P. Chan; Kenneth S. Pitzer

1993-01-01

49

DNA Templated Synthesis (DTS) -Nature's effective molarity based approach-  

E-print Network

DNA Templated Synthesis (DTS) -Nature's effective molarity based approach- Organic Seminar 27th May Translation DNA RNA Protein Replication mRNA tRNA Nucleic acid templated synthesis plays a important role X Y -CTGCC TGG -GACGGCACCAT CA X-Y DNA-templated synthesis (DTS) have the ability to direct

Katsumoto, Shingo

50

Excess Molar Volumes of Aqueous Solutions of Butylamine Isomers  

Microsoft Academic Search

Excess molar volumes (V ) and average thermal expansivities (?) of the systems, water (W) + n-butylamine (NBA), W + sec-butylamine (SBA), and W + tert-butylamine (TBA), have been calculated from the density data at temperatures ranging from 298.15–323.15 K. The V and ? values have been plotted as functions of mole fraction of amines. The systems show large negative

Muhammad A. Saleh; Shamim Akhtar; Ashiqur Rahman Khan

2000-01-01

51

Accidental displacement of impacted maxillary third molar: a case report  

Microsoft Academic Search

An unusual case of an impacted right maxillary third molar that was accidentally displaced into the maxillary sinus during exodontia and was surgically retrieved almost 2 years later is described. The tooth was removed under general anesthesia, after maxillary sinus exposure through Caldwell-Luc approach. Postoperative recovery was uneventful. Six months after the retrieval surgery, the maxillary sinus was completely healed

Cassio Edvard Sverzut; Alexandre Elias Trivellato; Luiz Marcel de Figueiredo; Emanuela Prado Ferraz; Alexander Tadeu Sverzut

2005-01-01

52

Molar mass of dry air in mass metrology  

Microsoft Academic Search

Since 1980, the different national metrology institutes use the same procedure and formula for air density determination. The formula employed assumes some hypotheses on the composition of dry air and is expressed in terms of its molar mass and the four environmental parameters: air pressure, air temperature and concentrations of carbon dioxide and water vapour. In this formula (known as

N. Khélifa; M. Lecollinet; M. Himbert

2007-01-01

53

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

54

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

55

In vivo subcellular localization of Mal de Río Cuarto virus (MRCV) non-structural proteins in insect cells reveals their putative functions.  

PubMed

The in vivo subcellular localization of Mal de Río Cuarto virus (MRCV, Fijivirus, Reoviridae) non-structural proteins fused to GFP was analyzed by confocal microscopy. P5-1 showed a cytoplasmic vesicular-like distribution that was lost upon deleting its PDZ binding TKF motif, suggesting that P5-1 interacts with cellular PDZ proteins. P5-2 located at the nucleus and its nuclear import was affected by the deletion of its basic C-termini. P7-1 and P7-2 also entered the nucleus and therefore, along with P5-2, could function as regulators of host gene expression. P6 located in the cytoplasm and in perinuclear cloud-like inclusions, was driven to P9-1 viroplasm-like structures and co-localized with P7-2, P10 and ?-tubulin, suggesting its involvement in viroplasm formation and viral intracellular movement. Finally, P9-2 was N-glycosylated and located at the plasma membrane in association with filopodia-like protrusions containing actin, suggesting a possible role in virus cell-to-cell movement and spread. PMID:22608534

Maroniche, Guillermo A; Mongelli, Vanesa C; Llauger, Gabriela; Alfonso, Victoria; Taboga, Oscar; del Vas, Mariana

2012-09-01

56

In vivo subcellular localization of Mal de Rio Cuarto virus (MRCV) non-structural proteins in insect cells reveals their putative functions  

SciTech Connect

The in vivo subcellular localization of Mal de Rio Cuarto virus (MRCV, Fijivirus, Reoviridae) non-structural proteins fused to GFP was analyzed by confocal microscopy. P5-1 showed a cytoplasmic vesicular-like distribution that was lost upon deleting its PDZ binding TKF motif, suggesting that P5-1 interacts with cellular PDZ proteins. P5-2 located at the nucleus and its nuclear import was affected by the deletion of its basic C-termini. P7-1 and P7-2 also entered the nucleus and therefore, along with P5-2, could function as regulators of host gene expression. P6 located in the cytoplasm and in perinuclear cloud-like inclusions, was driven to P9-1 viroplasm-like structures and co-localized with P7-2, P10 and {alpha}-tubulin, suggesting its involvement in viroplasm formation and viral intracellular movement. Finally, P9-2 was N-glycosylated and located at the plasma membrane in association with filopodia-like protrusions containing actin, suggesting a possible role in virus cell-to-cell movement and spread.

Maroniche, Guillermo A.; Mongelli, Vanesa C.; Llauger, Gabriela; Alfonso, Victoria; Taboga, Oscar [Instituto de Biotecnologia, CICVyA, Instituto Nacional de Tecnologia Agropecuaria (IB-INTA), Las cabanas y Los Reseros s/n. Hurlingham Cp 1686, Buenos Aires (Argentina)] [Instituto de Biotecnologia, CICVyA, Instituto Nacional de Tecnologia Agropecuaria (IB-INTA), Las cabanas y Los Reseros s/n. Hurlingham Cp 1686, Buenos Aires (Argentina); Vas, Mariana del, E-mail: mdelvas@cnia.inta.gov.ar [Instituto de Biotecnologia, CICVyA, Instituto Nacional de Tecnologia Agropecuaria (IB-INTA), Las cabanas y Los Reseros s/n. Hurlingham Cp 1686, Buenos Aires (Argentina)

2012-09-01

57

Corticotomy-assisted molar protraction with the aid of temporary anchorage device.  

PubMed

This case report describes the interdisciplinary management of a 58-year-old woman who was missing lower first molars and supraerupted maxillary first molars. The treatment plan included intrusion of the upper first molars and corticotomy-assisted mandibular second molar protraction with the aid of temporary anchorage devices. Miniscrews were effective in intrusion of the maxillary first molars and protraction of the lower second molars. Although good functional outcome was achieved in 41 months, the corticotomy-assisted procedure did not significantly reduce the treatment time. PMID:23834274

Uribe, Flavio; Janakiraman, Nandakumar; Fattal, Amine N; Schincaglia, Gian Pietro; Nanda, Ravindra

2013-11-01

58

On the apparent molar volumes of nonelectrolytes in water  

SciTech Connect

Apparent molar volumes of aqueous solutions of argon and xenon have been calculated using a previously developed comprehensive equation of state for nonelectrolyte systems. The equation consists of a virial expansion truncated after the fourth virial coefficient and a closed-form term approximating higher coefficients. Mixing rules are based on the composition dependence of virial coefficients, which is known from statistical mechanics. The equation accurately represents vapor-liquid and gas-gas equilibria for the Ar + H[sub 2]O and Xe + H[sub 2]O systems over wide ranges of pressure and temperature using two binary parameters. With the binary parameters determined from phase equilibrium data, the equation accurately predicts apparent molar volumes V[sub [phi

Anderko, A.; Chan, J.P.; Pitzer, K.S. (Lawrence Berkeley Lab., CA (United States))

1993-04-01

59

Molar volumes of aqueous and ethylene glycol solutions of tetrahydrofuran  

NASA Astrophysics Data System (ADS)

The densities of ethylene glycol solutions of tetrahydrofuran (THF) with 0-20 mol % THF were measured at 20-60°C and atmospheric pressure to an accuracy of 5 × 10-5 g/cm3. The apparent molar volumes of THF in the solutions were calculated and their concentration and temperature dependences determined. The results were compared with the apparent molar volumes of THF in aqueous systems calculated from the literature data. Minima were found on the concentration dependence of the apparent volume of THF for both aqueous and ethylene glycol solutions and changed differently as the temperature increased. The data obtained were discussed from the standpoint of solvophobic effects in aqueous and ethylene glycol solutions of THF.

Rodnikova, M. N.; Gunina, M. A.; Makarov, D. M.; Egorov, G. I.; Val'Kovskaya, T. M.

2011-09-01

60

Thermal correction to the molar polarizability of a Boltzmann gas  

SciTech Connect

Metrology in atomic physics has been crucial for a number of advanced determinations of fundamental constants. In addition to very precise frequency measurements, the molar polarizability of an atomic gas has recently also been measured very accurately. Part of the motivation for the measurements is due to ongoing efforts to redefine the International System of Units (SI), for which an accurate value of the Boltzmann constant is needed. Here we calculate the dominant shift of the molar polarizability in an atomic gas due to thermal effects. It is given by the relativistic correction to the dipole interaction, which emerges when the probing electric field is Lorentz transformed into the rest frame of the atoms that undergo thermal motion. While this effect is small when compared to currently available experimental accuracy, the relativistic correction to the dipole interaction is much larger than the thermal shift of the polarizability induced by blackbody radiation.

Jentschura, U. D. [Department of Physics, Missouri University of Science and Technology, Rolla, Missouri 65409-0640 (United States); Puchalski, M. [Department of Physics, Missouri University of Science and Technology, Rolla, Missouri 65409-0640 (United States); Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, PL-60-780 Poznan (Poland); Mohr, P. J. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8420 (United States)

2011-12-15

61

Radicular Cyst in Deciduous Maxillary Molars: A Rarity  

PubMed Central

Radicular cyst arising from deciduous teeth is exceedingly rare accounting for <1% of all radicular cysts. A total of 122 cases have been reported to date in the English language literature. We present a rare case of a radicular cyst associated with a decayed deciduous maxillary molar tooth without any history of prior pulp therapy. Our aim is to emphasize the recognition of inflammatory radicular lesions associated with deciduous teeth which may adversely impact underlying permanent successor. PMID:20237985

Shetty, Shibani; Rekha, K.

2009-01-01

62

Five Canalled and Three-Rooted Primary Second Mandibular Molar  

PubMed Central

A thorough knowledge of root canal anatomy and its variation is necessary for successful completion of root canal procedures. Morphological variations such as additional root canals in human deciduous dentition are rare. A mandibular second primary molar with more than four canals is an interesting example of anatomic variations, especially when three of these canals are located in the distal root. This case shows a rare anatomic configuration and points out the importance of looking for additional canals. PMID:25147744

Selvakumar, Haridoss; Kavitha, Swaminathan; Bharathan, Rajendran; Varghese, Jacob Sam

2014-01-01

63

Partial molar volumes of amino acid derivatives in water  

Microsoft Academic Search

The partial molar volumes at infinite dilution for a number of hydrochlorides and sodium salts of N-methyl derivatives of a, ?-aminocarboxylic acids in water at 25°C are measured and related to their van der Waals volumes. Results indicate that 4.96±0.48 water molecules hydrate a betaine hydrochloride. Volumes of proton ionization and interaction terms are evaluated. Group contributions to the partial

Fereidoon Shahidi

1983-01-01

64

Extrusion of impacted mandibular second molar using removable appliance  

PubMed Central

The purpose of this article is to review the principles of case management of impacted mandibular molars and to illustrate their potential to respond well to treatment. Although the scope of treatment may be influenced by the patient's age, past dental history, severity of impaction, dentoalveolar development, and root form, the case reports demonstrate the inherent potential for good treatment outcome even in the most unfavorable circumstances.

Karthikeyan, M. K.; Prabhakar, Ramachandran; Saravanan, R.; Vikram, N. Raj; Kumar, R. Vinoth; Prasath, R. Eshwara

2014-01-01

65

Developmental regulations of Perp in mice molar morphogenesis.  

PubMed

Teraspanin transmembrane protein, Perp (P53 apoptosis effector related to PMP22), which is found in the plasma membrane as a component of the desmosome, is reported to be involved in the morphogenesis of the epithelium and the enamel formation of the incisor. However, its expression pattern and signaling regulation during molar development have not been elucidated in detail. We have examined the precise expression patterns of Perp in developing lower molars and employed the knock-down of Perp by antisense oligodeoxynucleotide treatment during in vitro organ cultivation at embryonic day 13 to define the precise developmental function of Perp. Perp was expressed mainly in the dental lamina and stellate reticulum regions at the bud and cap stages. After Perp knock-down, the tooth germ showed disruption of the dental lamina and stellate reticulum with altered apoptosis and proliferation. The changed expression levels of related signaling molecules from the enamel knot and desmosome were evaluated by real-time quantitative polymerase chain reaction. A renal capsule transplantation method was employed to examine the effects of Perp knock-down on molar crown development. Ultrastructural observations revealed that enamel was deposited more densely in an irregular pattern in the cusp region, and that dentin was hypo-mineralized after Perp knock-down at the cap stage. Thus, Perp might play important roles in the formation and integration of stellate reticulum, dental lamina structure and enamel formation through signaling interactions with the enamel knot and desmosome-related signaling molecules at the cap stage of lower molar development. PMID:24865245

Neupane, Sanjiv; Sohn, Wern-Joo; Rijal, Girdhari; Lee, Ye-Ji; Lee, Sanggyu; Yamamoto, Hitoshi; An, Chang-Hyeon; Cho, Sung-Won; Lee, Youngkyun; Shin, Hong-In; Kwon, Tae-Yub; Kim, Jae-Young

2014-10-01

66

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. PMID:22926461

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

2012-01-01

67

Rescue surgery (surgical repositioning) of impacted lower second molars.  

PubMed

The impaction of lower second molars, given that its incidence is 0.03 to 0.21%, is a rare complication in tooth eruption. It has been detected more often in unilateral form than bilateral and is more common in the mandible than in the maxillary. It has a slight predilection for males, and mesial inclination is more usual. A wide variety of therapeutic approaches have been published, basically referring to surgical techniques, independent or complemented by means of orthodontic technical aids, with the aim of placing the tooth in the correct position, and which are encompassed under the concept of surgical rescue. In cases resolved with repositioning of an impacted tooth, prophylactic root extraction has been proposed as obligatory. We present a case of a 12 and a half year old patient referred to the University of Seville due to non-eruption of the left lower second molar. The patient was referred by her orthodontist, who detected the impaction before starting orthodontic treatment. The orthodontist requested that, if it was possible, we did not extract the root of the third molar, because its eruption would be feasible in the future (there would be sufficient space in the arch). The spaces available were measured and we decided to attempt the repositioning of the impacted tooth without extracting the root of the wisdom tooth, which was carried out successfully. PMID:16264380

García-Calderón, Manuel; Torres-Lagares, Daniel; González-Martín, Maribel; Gutiérrez-Pérez, José Luis

2005-01-01

68

Intranasal atomized dexmedetomidine for sedation during third molar extraction.  

PubMed

The purpose of this study was to evaluate the intranasal use of 1.5 ?g/kg atomized dexmedetomidine for sedation in patients undergoing mandibular third molar removal. Eighteen patients underwent third molar removal in two surgical sessions. Patients were randomly assigned to receive intranasal water (placebo group) or 1.5 ?g/kg atomized dexmedetomidine (group D) at the first session. The alternate regimen was used during the second session. Local anaesthesia was injected 30 min after placebo/sedative administration. Pain from local anaesthesia infiltration was rated on a scale from zero (no pain) to 10 (worst pain imaginable). Sedation status was measured every 10 min by a blinded observer with a modified Observer's Assessment of Alertness/Sedation (OAA/S) scale and the bispectral index (BIS). Adverse reactions and analgesic consumption were recorded. Sedation values in group D were significantly different from placebo at 20-30 min, peaked at 40-50 min, and returned to placebo levels at 70-80 min after intranasal drug administration. Group D displayed decreased heart rate and systolic blood pressure, but the decreases did not exceed 20% of the baseline values. Intranasal administration of 1.5 ?g/kg atomized dexmedetomidine is effective, convenient, and safe as a sedative for patients undergoing third molar extraction. PMID:23497981

Nooh, N; Sheta, S A; Abdullah, W A; Abdelhalim, A A

2013-07-01

69

Molar Macrowear Reveals Neanderthal Eco-Geographic Dietary Variation  

PubMed Central

Neanderthal diets are reported to be based mainly on the consumption of large and medium sized herbivores, while the exploitation of other food types including plants has also been demonstrated. Though some studies conclude that early Homo sapiens were active hunters, the analyses of faunal assemblages, stone tool technologies and stable isotopic studies indicate that they exploited broader dietary resources than Neanderthals. Whereas previous studies assume taxon-specific dietary specializations, we suggest here that the diet of both Neanderthals and early Homo sapiens is determined by ecological conditions. We analyzed molar wear patterns using occlusal fingerprint analysis derived from optical 3D topometry. Molar macrowear accumulates during the lifespan of an individual and thus reflects diet over long periods. Neanderthal and early Homo sapiens maxillary molar macrowear indicates strong eco-geographic dietary variation independent of taxonomic affinities. Based on comparisons with modern hunter-gatherer populations with known diets, Neanderthals as well as early Homo sapiens show high dietary variability in Mediterranean evergreen habitats but a more restricted diet in upper latitude steppe/coniferous forest environments, suggesting a significant consumption of high protein meat resources. PMID:21445243

Fiorenza, Luca; Benazzi, Stefano; Tausch, Jeremy; Kullmer, Ottmar; Bromage, Timothy G.; Schrenk, Friedemann

2011-01-01

70

Molar macrowear reveals Neanderthal eco-geographic dietary variation.  

PubMed

Neanderthal diets are reported to be based mainly on the consumption of large and medium sized herbivores, while the exploitation of other food types including plants has also been demonstrated. Though some studies conclude that early Homo sapiens were active hunters, the analyses of faunal assemblages, stone tool technologies and stable isotopic studies indicate that they exploited broader dietary resources than Neanderthals. Whereas previous studies assume taxon-specific dietary specializations, we suggest here that the diet of both Neanderthals and early Homo sapiens is determined by ecological conditions. We analyzed molar wear patterns using occlusal fingerprint analysis derived from optical 3D topometry. Molar macrowear accumulates during the lifespan of an individual and thus reflects diet over long periods. Neanderthal and early Homo sapiens maxillary molar macrowear indicates strong eco-geographic dietary variation independent of taxonomic affinities. Based on comparisons with modern hunter-gatherer populations with known diets, Neanderthals as well as early Homo sapiens show high dietary variability in Mediterranean evergreen habitats but a more restricted diet in upper latitude steppe/coniferous forest environments, suggesting a significant consumption of high protein meat resources. PMID:21445243

Fiorenza, Luca; Benazzi, Stefano; Tausch, Jeremy; Kullmer, Ottmar; Bromage, Timothy G; Schrenk, Friedemann

2011-01-01

71

Surgical extraction of deeply horizontally impacted mandibular second and third molars.  

PubMed

The presence of deeply horizontally impacted lower second and third molars is unusual. The arrested eruption of the lower second and third molars can determine disturbances of mastication and aesthetics. Moreover, an increased risk of caries in the distal side of the first lower molar is possible. Different therapeutic approaches could be proposed for second and third molar impaction and malposition. In this article, we report the management and the outcome of the surgical treatment of a patient with impacted mandibular second and third molars. PMID:20186075

Boffano, Paolo; Gallesio, Cesare; Bianchi, Francesca; Roccia, Fabio

2010-03-01

72

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

73

Restoration of Endodontically Treated Molars Using All Ceramic Endocrowns  

PubMed Central

Clinical success of endodontically treated posterior teeth is determined by the postendodontic restoration. Several options have been proposed to restore endodontically treated teeth. Endocrowns represent a conservative and esthetic restorative alternative to full coverage crowns. The preparation consists of a circular equigingival butt-joint margin and central retention cavity into the entire pulp chamber constructing both the crown and the core as a single unit. The case reports discussed here are moderately damaged endodontically treated molars restored using all ceramic endocrowns fabricated using two different systems, namely, CAD/CAM and pressed ceramic. PMID:24455318

Carlos, Roopak Bose; Thomas Nainan, Mohan; Pradhan, Shamina; Roshni Sharma; Benjamin, Shiny; Rose, Rajani

2013-01-01

74

[Cheek swelling after surgical removal of third molar].  

PubMed

A 55-years-old man visited his family doctor because of a one-day existing, not painful, right-sided swelling of the cheek. It appeared to be a subcutaneous emphysema, caused at an attempt to remove mandibular third molar roots, using a water- and air-cooled air rotor. Rare potential se?elae resulting from subcutaneous emphysema are venous air embolism, airway obstruction because of neck swelling, pneumomediastinum, and mediastinitis. Using air-cooled instruments in surgical orofacial treatments should be avoided because of the possible atrogenic life-threatening complications. PMID:16566402

van Essen, G A; de Baat, C

2006-03-01

75

The Prevalence of Bilateral Three-Rooted Mandibular First Molar in Indian Population  

PubMed Central

Introduction The purpose of the present study was to evaluate the prevalence of bilateral three-rooted mandibular first and second molars in Indian population. Materials and Methods A total of 215 patients were screened bilaterally for mandibular first and second molar and 430 samples of periapical radiographs were obtained. The gender, symmetry, and prevalence of three-rooted mandibular first and second molars were recorded. The correlation between left and right side occurrences and distribution were recorded and analysed using Z-test. Results The results showed that 33 teeth had three-rooted mandibular first molars, 16 male and 17 female (P=0.442). Overall, 21 teeth of right jaw and 12 teeth of left jaw (P=0.103) showed presence of an extra-root. The prevalence of three-rooted mandibular first molars was 7.67% and second molar was 0.23%. The bilateral frequency distribution was 3.72% for the first molar. There was no statistically significant difference between right side and left side mandibular molars. Also, gender did not show a significant relationship with this variant. Conclusion The endodontic treatments of first mandibular molars require a careful clinical approach in Indian population as a high racial prevalence of 7.67% three-rooted molars was found. However, in the same population, 0.23% mandibular second molars had three roots. PMID:23922569

Karale, Rupali; Chikkamallaiah, Champa; Hegde, Jayshree; Aswathanarayana, Srirekha; Santhosh, Lekha; Bashetty, Kusum; Rajanna Susheela, Shwetha; Panchajanya, Srinivas

2013-01-01

76

Compensation trends of the angulation of first molars: retrospective study of 1?403 malocclusion cases.  

PubMed

We investigated the compensatory trends of mesiodistal angulation of first molars in malocclusion cases. We compared differences in the angulation of first molars in different developmental stages, malocclusion classifications and skeletal patterns. The medical records and lateral cephalogrammes of 1?403 malocclusion cases taken before treatment were measured to evaluate compensation of molar angulation in relation to the skeletal jaw. The cases were stratified by age, Angle classification and skeletal patterns. Differences in the mesiodistal angulation of the first molars were compared among the stratifications. We observed three main phenomena. First, angulation of the upper first molar varied significantly with age and tipped most distally in cases aged <12 years and least distally in cases aged >16 years. The lower first molar did not show such differences. Second, in Angle Class II or skeletal Class II cases, the upper first molar was the most distally tipped, the lower first molar was the most mesially tipped, and opposite angulation compensation was observed in Class III cases. Third, in high-angle cases, the upper and lower first molars were the most distally tipped, and opposite angulation compensation was observed in low-angle cases. These data suggest that the angulation of the molars compensated for various growth patterns and malocclusion types. Hence, awareness of molar angulation compensation would help to adjust occlusal relationships, control anchorage and increase the chances of long-term stability. PMID:24699185

Su, Hong; Han, Bing; Li, Sa; Na, Bin; Ma, Wen; Xu, Tian-Min

2014-09-01

77

Compensation trends of the angulation of first molars: retrospective study of 1 403 malocclusion cases  

PubMed Central

We investigated the compensatory trends of mesiodistal angulation of first molars in malocclusion cases. We compared differences in the angulation of first molars in different developmental stages, malocclusion classifications and skeletal patterns. The medical records and lateral cephalogrammes of 1?403 malocclusion cases taken before treatment were measured to evaluate compensation of molar angulation in relation to the skeletal jaw. The cases were stratified by age, Angle classification and skeletal patterns. Differences in the mesiodistal angulation of the first molars were compared among the stratifications. We observed three main phenomena. First, angulation of the upper first molar varied significantly with age and tipped most distally in cases aged <12 years and least distally in cases aged >16 years. The lower first molar did not show such differences. Second, in Angle Class II or skeletal Class II cases, the upper first molar was the most distally tipped, the lower first molar was the most mesially tipped, and opposite angulation compensation was observed in Class III cases. Third, in high-angle cases, the upper and lower first molars were the most distally tipped, and opposite angulation compensation was observed in low-angle cases. These data suggest that the angulation of the molars compensated for various growth patterns and malocclusion types. Hence, awareness of molar angulation compensation would help to adjust occlusal relationships, control anchorage and increase the chances of long-term stability. PMID:24699185

Su, Hong; Han, Bing; Li, Sa; Na, Bin; Ma, Wen; Xu, Tian-Min

2014-01-01

78

Nanoparticle counting: towards accurate determination of the molar concentration.  

PubMed

Innovations in nanotechnology have brought tremendous opportunities for the advancement of many research frontiers, ranging from electronics, photonics, energy, to medicine. To maximize the benefits of nano-scaled materials in different devices and systems, precise control of their concentration is a prerequisite. While concentrations of nanoparticles have been provided in other forms (e.g., mass), accurate determination of molar concentration, arguably the most useful one for chemical reactions and applications, has been a major challenge (especially for nanoparticles smaller than 30 nm). Towards this significant yet chronic problem, a variety of strategies are currently under development. Most of these strategies are applicable to a specialized group of nanoparticles due to their restrictions on the composition and size range of nanoparticles. As research and uses of nanomaterials are being explored in an unprecedented speed, it is necessary to develop universal strategies that are easy to use and are compatible with nanoparticles of different sizes, compositions, and shapes. This review outlines the theories and applications of current strategies to measure nanoparticle molar concentration, discusses the advantages and limitations of these methods, and provides insights into future directions. PMID:25099190

Shang, Jing; Gao, Xiaohu

2014-11-01

79

Study of molar response of dextrans in electrochemical detection.  

PubMed

In this work, a methodological approach is reported, aimed at assessing the electrochemical response of some model gluco-oligosaccharides (dextrans). Such strategy is based on the complementary use of both anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and capillary zone electrophoresis coupled with UV detection (CZE-UV). Unlike HPAEC-PAD, CZE-UV required derivatization with a chromophoric dye (i.e., 8-aminonaphtalene-1,3,6-trisulphonic acid, ANTS) to enhance UV response and separation selectivity. From the comparison between chromophore response and PAD signal, the reliability of HPAEC-PAD for quantitative evaluation of dextran mixtures containing mainly oligomers with polymerization degree (DP) up to 18 could be proved, due to the fairly constant molar response. For higher DPs (up to 41), a maximum in the trend of the molar responses was observed followed by a steep decrease for DPs higher than about 30-35; indeed, an underestimation of weight-average molecular weight of dextran mixtures containing such oligomers was noticed. PMID:17188282

Abballe, Franco; Toppazzini, Mila; Campa, Cristiana; Uggeri, Fulvio; Paoletti, Sergio

2007-05-11

80

Nanomechanical Behavior of Human Molars Soaked in Slight Acid Solutions  

NASA Astrophysics Data System (ADS)

This paper studied the mechanical and chemical properties of hydroxyl apatite (HA) crystal structure in the teeth when human molars were soaked in slight acid solution. First, we soaked the ground and polished molars respectively in the liquor of 30 wt.% H2CO3 and the liquor of 30 wt.% H2O2 for 10, 20, or 60 minutes. Next, we used a nanoindenter to measure the hardness and Young's modulus. Finally, we used a scanning electron microscope (SEM) coupled with energy dispersive spectroscopy (EDS) to analyze the variation of Ca, P and Na in teeth, a high resolution transmitting electron microscope (HRTEM) to observe the arrangement of crystallization phase of HA, and X-ray diffraction (XRD) to analyze the crystallinity of the hexagonal phase of HA. The results showed that the demineralization phenomenon of the calcium-phosphorous compound in teeth made the teeth reduce sharply in hardness and Young's modulus after they were soaked in the two slight acid solutions for 10 minutes, but the re-mineralization phenomenon made the hardness and Young's modulus ascend gradually when the time lasted longer. With the same period of time, the teeth soaked in H2CO3 were lower in the hardness and Young's modulus than that in H2O2.

Fang, Te-Hua; Chang, Win-Jin; Kang, Shao-Hui; Chu, Chia-Chun

81

Infinitely dilute partial molar properties of proteins from computer simulation.  

PubMed

A detailed understanding of temperature and pressure effects on an infinitely dilute protein's conformational equilibrium requires knowledge of the corresponding infinitely dilute partial molar properties. Established molecular dynamics methodologies generally have not provided a way to calculate these properties without either a loss of thermodynamic rigor, the introduction of nonunique parameters, or a loss of information about which solute conformations specifically contributed to the output values. Here we implement a simple method that is thermodynamically rigorous and possesses none of the above disadvantages, and we report on the method's feasibility and computational demands. We calculate infinitely dilute partial molar properties for two proteins and attempt to distinguish the thermodynamic differences between a native and a denatured conformation of a designed miniprotein. We conclude that simple ensemble average properties can be calculated with very reasonable amounts of computational power. In contrast, properties corresponding to fluctuating quantities are computationally demanding to calculate precisely, although they can be obtained more easily by following the temperature and/or pressure dependence of the corresponding ensemble averages. PMID:25325571

Ploetz, Elizabeth A; Smith, Paul E

2014-11-13

82

Radiographic evaluation of third molar development in 6- to 24-year-olds  

PubMed Central

Purpose This study investigated the developmental stages of third molars in relation to chronological age and compared third molar development according to location and gender. Materials and Methods A retrospective analysis of panoramic radiographs of 2490 patients aged between 6 and 24 years was conducted, and the developmental stages of the third molars were evaluated using the modified Demirjian's classification. The mean age, standard deviation, minimal and maximal age, and percentile distributions were recorded for each stage of development. A Mann-Whitney U test was performed to test the developmental differences in the third molars between the maxillary and mandibular arches and between genders. A linear regression analysis was used for assessing the correlation between the third molar development and chronological age. Results The developmental stages of the third molars were more advanced in the maxillary arch than the mandibular arch. Males reached the developmental stages earlier than females. The average age of the initial mineralization of the third molars was 8.57 years, and the average age at apex closure was 21.96 years. The mean age of crown completion was 14.52 and 15.04 years for the maxillary and the mandibular third molars, respectively. Conclusion The developmental stages of the third molars clearly showed a strong correlation with age. The third molars developed earlier in the upper arch than the lower arch; further, they developed earlier in males than in females. PMID:25279338

Jung, Yun-Hoa

2014-01-01

83

An in vitro morphological investigation of the endodontic spaces of third molars.  

PubMed

Aim of this paper was to investigate the particular anatomic features of the endodontic space of third molars in the general population of Croatia. A total of 106 fully developed third molars (56 maxillar and 50 mandibular) has been analyzed. The respective number of roots and of root canals, the structure of the roots, and the curvature and absolute length of the root-canals were analyzed. In most cases, upper third molars had three roots (83.9%), while most of the lower molars were single rooted (56.0%). Upper third molars had mostly three root canals (75.1%), lower third molars two (90.0%). In both jaws, most third molars had curved canals (60.7% in the upper and 84.0% in the lower jaw). 12.5% of upper third molars had lateral and accessory canals, whereas only 4.0% of the lower third molars were found to have them. The Student t-test showed statistically significant differences (p < 0.05) in the length of the root-canals, mesiobuccal and distobuccal canals being significantly shorter than palatinal canals. The same test showed that in the lower third molars the mesial root canals were significantly longer that the distal ones, although slightly. The results obtained are in compliance with similar results by other authors; however, they tend to show some specific population-related features. PMID:23940986

Cosi?, Jozo; Gali?, Nada; Vodanovi?, Marin; Njemirovskij, Vera; Segovi?, Sanja; Paveli?, Bozidar; Ani?, Ivica

2013-06-01

84

Rotation of rectangular wire in rectangular molar tubes. Part I.  

PubMed

The degree of angular rotation of rectangular orthodontic wires in rectangular molar tubes was measured using a rotatable mechanical stage on a Unitron metallograph and compared to theoretical data. It was found that square 0.016 inch wire did not bind in 0.018 by 0.022 inch or larger mandrel- or inconel-formed tubes, whereas rotations of 11 to 23 degrees were noted in cast tubes of this dimension. Although 0.016 by 0.022 inch wire did bind in these tubes, the degree of rotation was far greater than expected on the basis of theoretical calculations or clinical expectations. The results indicated that it was unrealistic to expect fine control of a few degrees of torque to occur as expected for delicate clinical control. PMID:6943934

Raphael, E; Sandrik, J L; Klapper, L

1981-08-01

85

[The pendulis appliance: a palatal miniscrew supported molar distalization device].  

PubMed

The maxillary molar distalization is a valuable therapeutic option in some clinical cases. Its biomechanics is challenging and difficult to obtain. Historically, various devices have been described offering successful solutions to this problem such as the Hilgers Pendulum Appliance (1992) and variants linked to mini screws which recently have shown interesting clinical potential. This article presents a new Pendulum variant using a miniscrew, the "pendulis". It follows the original concept (titanium-molybdenum alloy distalization springs and polymethyl-methacrylate pellet) but dental support is replaced by a single palatal miniscrew (median adults, para-median in children) to which the device is fixed by means of a metal welded cap easily positioned and removable by the practitioner. This allows for better control of the oral hygiene and completely controlled extraoral activation. Fabrication steps are described and instruction of use is illustrated with clinical documentation. PMID:25158749

Nappée-Miévilly, Magali; Nappée, François-Joseph; Kerbrat, Jean-Baptiste; Goudot, Patrick

2014-09-01

86

Intra- and interspecific variation in macaque molar enamel thickness.  

PubMed

Enamel thickness has played an important role in studies of primate taxonomy, phylogeny, and functional morphology, although its variation among hominins is poorly understood. Macaques parallel hominins in their widespread geographic distribution, relative range of body sizes, and radiation during the last five million years. To explore enamel thickness variation, we quantified average and relative enamel thickness (AET and RET) in Macaca arctoides, Macaca fascicularis, Macaca fuscata, Macaca mulatta, Macaca nemestrina, and Macaca sylvanus. Enamel area, dentine area, and enamel-dentine junction length were measured from mesial sections of 386 molars scanned with micro-computed tomography, yielding AET and RET indices. Intraspecific sex differences were not found in AET or RET. Macaca fuscata had the highest AET and RET, M. fascicularis showed the lowest AET, and M. arctoides had the lowest RET. The latitudinal distribution of macaque species was associated with AET for these six species. Temperate macaques had thicker molar enamel than did tropical macaques, suggesting that thick enamel may be adaptive in seasonal environments. Additional research is needed to determine if thick enamel in temperate macaques is a response to intensified hard-object feeding, increased abrasion, and/or a broader diet with a greater range of food material properties. The extreme ecological flexibility of macaques may prohibit identification of consistent trends between specific diets and enamel thickness conditions. Such complications of interpretation of ecological variability, dietary diversity, and enamel thickness may similarly apply for fossil Homo species. Am J Phys Anthropol 155:447-459, 2014. © 2014 Wiley Periodicals, Inc. PMID:25146639

Kato, Akiko; Tang, Nancy; Borries, Carola; Papakyrikos, Amanda M; Hinde, Katie; Miller, Ellen; Kunimatsu, Yutaka; Hirasaki, Eishi; Shimizu, Daisuke; Smith, Tanya M

2014-11-01

87

UPPER VS. LOWER MOLARS FOR CEMENTUM ANNULI AGE DETERMINATION OF DEER  

Microsoft Academic Search

Ages were determined for 23 black-tailed deer (Odocoileus hemionus columbianus) and 14 white-tailed deer (0. virginianus) by examination of cementum annuli of both upper and lower 1st molars. Although estimated ages were virtually the same for both upper and lower molars, the clarity of annuli was significantly greater in upper molars for both species. Abstract: Ages were determined for 23

DALE R. McCULLOUGH; PAUL BEIER

88

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

89

Human molars from later Pleistocene deposits of Witkrans Cave, Gaap Escarpment, Kalahari Margin  

Microsoft Academic Search

Human molars from travertine deposits of Witkrans Cave (Gaap Escarpment, northern Cape Province, South Africa) are described.\\u000a The Witkrans molars were discovered in direct association with later Pleistocene faunal remains and a sample of Middle Stone\\u000a Age artifacts (Peabody, 1954; Clark, 1971; Sampson, 1974; Klein, 1984; Volman, 1984). The morphology and dimensions of the\\u000a Witkrans molars resemble remains from other

Monte L. McCrossin

1992-01-01

90

Relationships between the molar volumes of mixtures of elements and their compounds  

Microsoft Academic Search

The molar volumes of stoichiometric mixtures of Group I–III metals and Group V–VII nonmetals are compared with the molar volumes\\u000a of MX compounds. The derivatives of the B-subgroup metals have the molar volumes larger than the mixtures. The compounds of\\u000a A-subgroup metals have smaller volumes than the mixtures. A crystal-chemical interpretation of this fact is advanced.

S. S. Batsanov

2006-01-01

91

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

92

Statistical genetics of molar cusp patterning in pedigreed baboons: implications for primate dental development and evolution.  

PubMed

Gene expression and knock-out studies provide considerable information about the genetic mechanisms required for tooth organogenesis. Quantitative genetic studies of normal phenotypic variation are complementary to these developmental studies and may help elucidate the genes and mechanisms that contribute to the normal population-level phenotypic variation upon which selection acts. Here we present the first quantitative genetic analysis of molar cusp positioning in mammals. We analyzed quantitative measures of molar cusp position in a captive pedigreed baboon breeding colony housed at the Southwest National Primate Research Center in San Antonio, Texas. Our results reveal complete pleiotropy between antimeric pairs of traits--i.e., they are influenced by the same gene or suite of genes. Mandibular morphological homologues in the molar series also exhibit complete pleiotropy. In contrast, morphological homologues in maxillary molar series appear to be influenced by partial, incomplete pleiotropic effects. Variation in the mandibular mesial and distal molar loph orientation on the same molar crown is estimated to be genetically independent, whereas the maxillary molar mesial and distal loph orientation is estimated to have partially overlapping genetic affects. The differences between the maxillary and mandibular molar patterning, and the degree of genetic independence found between lophs on the same molar crown, may be indicative of previously unrecognized levels of modularity in the primate dentition. PMID:15211686

Hlusko, Leslea J; Maas, Mary-Louise; Mahaney, Michael C

2004-05-15

93

Image analysis of the eruptive positions of third molars and adjacent second molars as indicators of age evaluation in Thai patients  

PubMed Central

Purpose This study was performed to determine the relationship between the stage of tooth eruption (both vertical and mesio-angular) and chronological age. Materials and Methods Indirect digital panoramic radiographs were used to measure the distances from the dentinoenamel junction (DEJ) of the second molars to the occlusal plane of the second molar teeth and of the adjacent third molars in 264 Thai males and 437 Thai females using ImageJ software. The ratio of those distances was calculated by patient age, and the correlation coefficient of the ratio of the third molar length to the second molar length was calculated. Results The correlation between the height of the vertically erupted upper third molar teeth and age was at the intermediate level. The age range of ?15 to <16 years was noted to be the range in which the correlation between the chronological age determined from the eruptional height and actual chronological age was statistically significant. The mean age of the female subjects, in which the position of the right upper third molar teeth was at or above the DEJ of the adjacent second molar but below one half of its coronal height was 19.9±2.6 years. That for the left side was 20.2±2.7 years. The mean ages of the male subjects were 20.1±3.3 years and 19.8±2.7 years for the right and left sides, respectively. Conclusion It might be possible to predict chronological age from the eruption height of the wisdom teeth. PMID:24380069

Pramojanee, Sakarat; Thaiupathump, Trasapong

2013-01-01

94

Modified Distal Shoe Appliance for Premature Loss of Multiple Deciduous Molars: A Case Report  

PubMed Central

Preservation of the primary dentition until the normal time of exfoliation is one of the most important factor involved in preventive and interceptive dentistry. The premature loss of second primary molar before the eruption of permanent first molar can create a significant arch space/tooth size discrepancy. Distal shoe space maintainer is a valuable part of the Paediatric Dentist’s armamentarium in those cases where the second primary molar is prematurely lost and it helps to guide the first permanent molar into place. Conventional design poses various limitations in cases of premature loss of multiple deciduous molars. Thus, it is required to modify the conventional designs according to the needs of the patient. This case report describes an innovative modification of distal shoe appliance in cases of premature loss of multiple deciduous molars. In the present case, modification of distal shoe space maintainer was advocated because of inadequate abutments caused due to multiple loss of deciduous molars. Bilateral design of distal shoe was planned for unilateral loss of deciduous molars. PMID:25302284

K., Navin H.; Idris, Mohammed; Christopher, Pradeep; Rai, Niharika

2014-01-01

95

A new method to correct lingual rolling of lower molars (Amini twister).  

PubMed

In this report, we present an uncomplicated approach to overcome lingual rolling of mandibular molars during orthodontic treatment, by using rectangular NiTi arch wire in twist fashion through the molar tube. The sequential steps of the twist manoeuvre on a typodont and a case report are exhibited in this article. PMID:23729138

Amini, Fariborz; Poosti, Maryam

2013-01-01

96

High school students' ability to solve molarity problems and their analog counterparts  

Microsoft Academic Search

The study investigates the use of analog tasks for determining difficulties that high school chemistry students might encounter in solving molarity problems. Students (n = 619) from five schools completed three tests given throughout the school year. These were: an analog test, a molarity test, and a retention test. The analog task consisted of dissolving lemonade powder for solid sodium

Dorothy L. Gabel; K. V. Samuel

1986-01-01

97

Effect of submucosal and intramuscular dexamethasone on postoperative sequelae after third molar surgery: comparative study  

Microsoft Academic Search

We compared the effects of dexamethasone sodium phosphate given submucosally and intramuscularly on postoperative complications after removal of impacted lower third molars in a preliminary randomised prospective clinical trial. Thirty patients, each of whom required removal of a single impacted mandibular third molar under local anaesthesia, were randomly allocated to one of 3 groups of 10 each. The 2 experimental

Omer Waleed Majid; Waseem Khalid Mahmood

98

The influence of the group V/III molar precursor ratio on the structural properties  

E-print Network

, the precursors were temporally embedded in a nitrogen carrier gas stream, such that the total flow and pressureThe influence of the group V/III molar precursor ratio on the structural properties of InGaN layers, University of California, Irvine, CA 92697-2375, USA The influence of the group V/III molar precursor ratio

Dietz, Nikolaus

99

Modified distal shoe appliance for premature loss of multiple deciduous molars: a case report.  

PubMed

Preservation of the primary dentition until the normal time of exfoliation is one of the most important factor involved in preventive and interceptive dentistry. The premature loss of second primary molar before the eruption of permanent first molar can create a significant arch space/tooth size discrepancy. Distal shoe space maintainer is a valuable part of the Paediatric Dentist's armamentarium in those cases where the second primary molar is prematurely lost and it helps to guide the first permanent molar into place. Conventional design poses various limitations in cases of premature loss of multiple deciduous molars. Thus, it is required to modify the conventional designs according to the needs of the patient. This case report describes an innovative modification of distal shoe appliance in cases of premature loss of multiple deciduous molars. In the present case, modification of distal shoe space maintainer was advocated because of inadequate abutments caused due to multiple loss of deciduous molars. Bilateral design of distal shoe was planned for unilateral loss of deciduous molars. PMID:25302284

Bhat, Prasanna Kumar; K, Navin H; Idris, Mohammed; Christopher, Pradeep; Rai, Niharika

2014-08-01

100

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

101

Mole, Mole per Liter, and Molar: A Primer on SI and Related Units for Chemistry Students  

Microsoft Academic Search

This review provides historical background on the terms mole, mole per liter, and molar as it discusses their status with respect to the SI system of measurement. Currently the prevalent use of mole per liter and molar does not conform with the recommendations which apply to SI units in general. The article suggests an approach for dealing with this problem

George Gorin

2003-01-01

102

Management of unilaterally deep impacted first, second, and third mandibular molars.  

PubMed

Simultaneous impactions of first, second, and third permanent molars comprises a very rare clinical situation with diverse therapeutic approaches and is a difficult challenge for dentists. Early diagnosis and treatment of eruption disturbances contributes to optimal outcomes. This article reports the treatment of a teenager with severe impaction of right mandibular first, second, and third molars, which hinders the masticatory function and dental arch integrity. A decision-making process and a simple orthodontic technique are described. To shorten the treatment time and simplify the procedures, the impacted right mandibular third and second molars were orthodontically uprighted with an innovative tip-back cantilever. Subsequently, the deeply impacted right mandibular first molar was extracted with minimal obstacles. The combined surgical-orthodontic approach resolved a challenging clinical problem and eliminated the need for prosthetic or dental implant replacement of the impacted molars. Good occlusion, normal function, and a healthy periodontium of the patient were also achieved. PMID:21988519

Fu, Po-Sung; Wang, Jen-Chyan; Chen, Cheng-Hwei; Huang, Ta-Ko; Tseng, Chin-Huang; Hung, Chun-Cheng

2012-05-01

103

Management of an ectopically erupting permanent mandibular molar: a case report.  

PubMed

Ectopically erupting permanent first molars occur in approximately 3% to 4% of children, and presentation in the mandible is very rare. When the malocclusion warrants a nonextraction treatment plan in the mandible, early correction of an impacted ectopic molar with space regaining is appropriate. The purpose of this case report was to describe and document the correction of a severely impacted permanent mandibular left first molar in the early mixed dentition along with long-term results. A bilateral lingual arch was placed on the primary mandibular second molars with a Halterman-type extension in conjunction with a bonded button on the occlusal surface of the impacted permanent molar and chain elastic Early space regaining allowed future nonextraction treatment. PMID:18402102

Kennedy, David B

2008-01-01

104

Optimization of the mineral content in polymeric gels: The effect of calcium to phosphate molar ratio  

NASA Astrophysics Data System (ADS)

The influence of calcium to phosphate (Ca/P) molar ratio on the extent of mineralization in a model (poly)acrylamide gel was investigated under simulated physiological conditions. We hypothesized that the optimal growth of hydroxyapatite crystals will take place at the stoichiometric Ca/P molar ratio of 1.67. Phosphate ions were incorporated during the polymerization of the gel and mineralization was initiated by submersion of the gel in calcium acetate solution. Ca/P molar ratios were varied in the range of 0.5-5.0. The mineralized gel was characterized by Raman spectroscopy, scanning electron microscopy (SEM) and mineral weight fraction analysis via ashing. Raman spectra captured across the bulk of the gels indicated the presence of mineral at the core section. The phosphate symmetric stretching peak was observed in the range of 955-960 cm -1 which is characteristic of hydroxyapatite. SEM images showed that crystals formed at Ca/P=2.0 were denser and larger in size than at other molar ratios. In agreement with SEM images, the dry weight fraction of mineral reached the maximum at the molar ratio of 2.0 and the extent of mineralization rapidly declined as the molar ratio diverged from 2.0. Also, the crystallinity of the mineral was optimum at the molar ratio of 2.0. Thus it appears that for effective mineralization, the molar ratio of the two ions needs to be in excess of the stoichiometric requirement, suggesting that ions are expended in processes other than the formation and growth of hydroxyapatite crystals. Therefore, the optimal level of mineralization in biomimetic-based growth of calcium phosphate crystals in sol-gel environment requires consideration of a range of molar ratios as opposed to using the molar ratios corresponding to that of the crystal species intended to grow.

Das, Prasenjit; Akkus, Ozan; Azad, Abdul-Majeed

2005-07-01

105

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. PMID:23482647

Balaji, S. M.

2011-01-01

106

Molar absorptivities and reducing capacity of pyranoanthocyanins and other anthocyanins.  

PubMed

To improve accuracy in the determination of anthocyanin purity and succeeding antioxidant capacity, 1H and 13C nuclear magnetic resonance spectroscopy have been combined with high-performance liquid chromatography (HPLC) equipped with a diode array detector and UV-vis spectroscopy in the analysis of anthocyanidin 3-glycosides and 5-carboxypyranoanthocyanidin 3-glycosides. The molar absoptivity (epsilon) values were found to be relatively similar, in contrast to previously reported literature values, and the average epsilon values for both anthocyanidin 3-monoglycosides and 5-carboxypyranoanthocyanidin 3-glycosides were proposed to be 22,000 and 23,000 in acidified aqueous and methanolic solutions, respectively. To assess the influence of structure on the potential antioxidant capacity of anthocyanins, the 3-glucosides of pelargonidin (1), cyanidin (2), peonidin (3), delphinidin (4), petunidin (5), malvidin (6), 5-carboxypyranopelargonidin (8), 5-carboxypyranocyanidin (9), 5-carboxypyranodelphinidin (11), 5-carboxypyranopetunidin (12), and 5-carboxypyranomalvidin (13) and the 3-galactosides of cyanidin (7) and 5-carboxypyranocyanidin (14) were examined by a ferric ion reducing antioxidant power (FRAP) assay. The reducing capacities of the individual anthocyanins were in the range of 0.9-5.2 micromol of Trolox equivalents/micromol. The two 5-carboxypyranoanthocyanins 11 and 9 and the four common anthocyanins 2, 4, 7, and 14, all possessing pyrogallol or catechol type of B rings, showed the highest antioxidant capacity measured by FRAP. However, the inclusion of the 5-hydroxyl in the D ring and just one oxygen substituent on the B ring in 8 diminished the reducing capacity considerably. Correspondingly, electrochemical behavior of 5-carboxypyranoanthocyanidin 3-glucosides and anthocyanidin 3-glucosides was derived using HPLC coupled to a coulometric array detector set from 100 to 800 mV in increments of 100 mV. The relative order of the reducing capacity of the various 5-carboxypyranoanthocyanidin 3-glucosides and anthocyanidin 3-glucosides were nearly alike, whether determined by coulometric array detection or FRAP. PMID:18047275

Jordheim, Monica; Aaby, Kjersti; Fossen, Torgils; Skrede, Grete; Andersen, Øyvind M

2007-12-26

107

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. PMID:24072974

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

2013-01-01

108

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. PMID:23412400

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

2013-01-01

109

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

110

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

111

Accidental Displacement of Third Molar into the Sublingual Space: a Case Report  

PubMed Central

ABSTRACT Background Successful extraction of third molars depends on preoperative diagnosis and planning. Gold standard preoperative examinations are performed through computed tomography, decreasing risks and avoiding potential accidents. The present report highlights the value of preoperative examinations in face of accidentally displaced third molars. Methods An 18-years-old female patient underwent a third mandibular molar extraction with a general dentist. Accidentally, the mandibular left third molar was displaced into the sublingual space, making necessary a second surgical step. The surgery was interrupted and the patient was referred to an expert in maxillofacial surgery. Results After 21 days awaiting an asymptomatic health status, the second surgical step was successfully performed using multislice computed tomography as preoperative imaging guide. Conclusions The present case report highlights the clinical usefulness of imaging planning and informed consents in face of legal and ethic potential complaints. PMID:25386232

Garcia, Robson Rodrigues; Botelho, Tessa Lucena; Franco, Ademir; Silva, Rhonan Ferreira

2014-01-01

112

Complications following removal of impacted third molars: the role of the experience of the surgeon.  

PubMed

The incidence of complications associated with the removal of impacted third molars in a group of 500 patients treated by oral surgery faculty were compared with the incidence of complications in 208 patients treated during the same period by residents of oral and maxillofacial surgery. The results show that complications were more numerous after the removal of third molars classified as partial bony or complete bony impactions, and that less-experienced surgeons had a significantly higher incidence of such complications. PMID:3464711

Sisk, A L; Hammer, W B; Shelton, D W; Joy, E D

1986-11-01

113

Measurements and analysis of excess molar volumes for the ternary mixture MTBE + 1-pentanol + decane  

Microsoft Academic Search

Summary Densities at 298.15 K and atmospheric pressure have been measured, using a DMA 4500 Anton Paar densimeter, for the ternary mixture methyl tert-butyl ether (MTBE)+1-pentanol+decane and for the involved binary mixtures MTBE+1-pentanol and 1-pentanol+decane. The excess molar volumes for the binary mixture MTBE+decane was reported in an earlier work [1]. In addition, excess molar volumes were determined from the

P. V. Verdes; M. M. Mato; J. Salgado; J. L. Legido; M. I. Paz Andrade

2005-01-01

114

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. PMID:23633874

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

2013-01-01

115

Optimization of the mineral content in polymeric gels: The effect of calcium to phosphate molar ratio  

Microsoft Academic Search

The influence of calcium to phosphate (Ca\\/P) molar ratio on the extent of mineralization in a model (poly)acrylamide gel was investigated under simulated physiological conditions. We hypothesized that the optimal growth of hydroxyapatite crystals will take place at the stoichiometric Ca\\/P molar ratio of 1.67. Phosphate ions were incorporated during the polymerization of the gel and mineralization was initiated by

Prasenjit Das; Ozan Akkus; Abdul-Majeed Azad

2005-01-01

116

Alternative approach to management of early loss of second primary molar: a clinical case report.  

PubMed

Preservation of space after premature loss of the second primary molar is essential to prevent mesial drifting of the permanent first molar. Various modifications of distal shoe space maintainers, which have been documented, are all nonfunctional in nature. This paper describes an innovative design of a functional distal shoe space maintainer that is intended to overcome the disadvantages of conventional non-functional space maintainers and that does not hamper the periodontal status of the abutment tooth. PMID:25087351

Agarwal, Ravi; Chaudhry, Kalpna; Yeluri, Ramakrishna; Singh, Chanchal; Munshi, Autar K

2014-05-01

117

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

118

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

119

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

120

The addition of hydrogen bromide to propyne in equal molar quantities  

E-print Network

CONSTANTS, EXPERIMENTAL RESULTS. DISCUSSION, CONCLUSION. APPENDIX, REFERENCES. Page 10 16 17 22 2B 34 TABLE OF FIGURES Figure Apparatus Diagram. Infrared Spectra of Fraction Distilling Between 56 and 59 Degrees Centigrade (Reaction 58...). Page 12 Infrared Spectra (Reaction 58). Infrared Spectra (Reaction 54), of l-Bromopropene of 2-Bromopropene THE ADDITION OF HYDROGEN BROMIDE TO PROPYNE IN EQUAL MOLAR QUANTITIES INTRODUCTION In a reaction involving equal molar quantities...

Mejia, Joe Marcus

2012-06-07

121

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

122

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. PMID:23631557

2013-01-01

123

Degeneration of fungiform and circumvallate papillae following molar extraction in rats.  

PubMed

Abstract Objective. Proper occlusion facilitates food intake and gustatory function is indispensable for the enjoyment of food. Although an interaction between dentoalveolar and gustatory afferent neurons has been suggested by previous studies, the relationship between occlusion and gustation remains unclear. This study investigated the effect of upper molar extraction which diminished occlusal support on peripheral gustatory receptors in rats. Materials and methods. Thirty-six 7-week-old male Wistar rats were randomly assigned to either the experimental or the control group. All maxillary molars were extracted from rats in the experimental group under anesthesia, while a sham operation was conducted in the control group. The rats were euthanized 7, 14 or 28 days after the procedure. The morphology of the circumvallate papillae and taste buds using immunohistochemical methods and the fungiform papillae were visualized with 1% methylene blue. Results. Defects in the gustatory epithelium were observed after maxillary molar extraction. Rats in the experimental group had significantly fewer fungiform papillae, narrower circumvallate papillae, shallower trench depth, smaller trench area, smaller taste bud area, lower ratios of taste bud area to trench area and fewer taste buds than those in the control group. Conclusions. The findings indicate that molar extraction would affect peripheral gustatory receptors. This is the first study to characterize changes in rat fungiform and circumvallate papillae after maxillary molar extraction. This study suggests a possible synergic relationship between dentoalveolar perception and gustatory function, which has clinical implications that occlusion is closely correlated with gustatory perception. PMID:24866919

Hsu, Jui-Chin; Watari, Ippei; Ono, Rieko; Privatananupunt, Jutiporn; Mizumachi-Kubono, Mariko; Honda, Koji; Ishida, Yuji; Ono, Takashi

2014-11-01

124

In vitro evaluation of an alternative method to bond molar tubes  

PubMed Central

Despite the advances in bonding materials, many clinicians today still prefer to place bands on molar teeth. Molar bonding procedures need improvement to be widely accepted clinically. Objective The purpose of this study was to evaluate the shear bond strength when an additional adhesive layer was applied on the occlusal tooth/tube interface to provide reinforcement to molar tubes. Material and methods Sixty third molars were selected and allocated to the 3 groups: group 1 received a conventional direct bond followed by the application of an additional layer of adhesive on the occlusal tooth/tube interface, group 2 received a conventional direct bond, and group 3 received a conventional direct bond and an additional cure time of 10 s. The specimens were debonded in a universal testing machine. The results were analyzed statistically by ANOVA and Tukey’s test (?=0.05). Results Group 1 had a significantly higher (p<0.05) shear bond strength compared to groups 2 and 3. No difference was detected between groups 2 and 3 (p>0.05). Conclusions The present in vitro findings indicate that the application of an additional layer of adhesive on the tooth/tube interface increased the shear bond strength of the bonded molar tubes. PMID:21437468

PINZAN-VERCELINO, Célia Regina Maio; PINZAN, Arnaldo; GURGEL, Júlio de Araújo; BRAMANTE, Fausto Silva; PINZAN, Luciana Maio

2011-01-01

125

Mineralization of mandibular third molars can estimate chronological age--Brazilian indices.  

PubMed

Forensic age estimation is an important element of anthropological research, as it produces one of the primary sources of data that researchers use to establish the identity of a person living or the identity of unknown bodily remains. The aim of this study was to determine if the chronology of third molar mineralization could be an accurate indicator of estimated age in a sample Brazilian population. If so, mineralization could determine the probability of an individual being 18 years or older. The study evaluated 407 panoramic radiographs of males and females from the past 5 years in order to assess the mineralization status of the mandibular third molars. The evaluation was carried out using an adaptation of Demirjian's system. The results indicated a strong correlation between chronological age and the mineralization of the mandibular third molars. The results indicated that modern Brazilian generation tends to demonstrate an earlier mandibular third molar mineralization than older Brazilian generation and people of other nationalities. Males reached developmental stages slightly earlier than females, but statistically significant differences between the sex were not found. The probability that an individual with third molar mineralization stage H had reached an age of 18 years or older was 96.8-98.6% for males and females, respectively. PMID:22257966

de Oliveira, Fernando Toledo; Capelozza, Ana Lúcia Álvares; Lauris, José Roberto Pereira; de Bullen, Izabel Regina Fischer Rubira

2012-06-10

126

Evc regulates a symmetrical response to Shh signaling in molar development.  

PubMed

Tooth morphogenesis involves patterning through the activity of epithelial signaling centers that, among other molecules, secrete Sonic hedgehog (Shh). While it is known that Shh responding cells need intact primary cilia for signal transduction, the roles of individual cilia components for tooth morphogenesis are poorly understood. The clinical features of individuals with Ellis-van Creveld syndrome include various dental anomalies, and we show here that absence of the cilial protein Evc in mice causes various hypo- and hyperplasia defects during molar development. During first molar development, the response to Shh signaling is progressively lost in Evc-deficient embryos and, unexpectedly, the response consistently disappears in a buccal to lingual direction. The important role of Evc for establishing the buccal-lingual axis of the developing first molar is also supported by a displaced activity of the Wnt pathway in Evc mutants. The observed growth abnormalities eventually manifest in first molar microdontia, disruption of molar segmentation and symmetry, root fusions, and delayed differentiation. Analysis of our data indicates that both spatially and temporally disrupted activities of the Shh pathway are the primary cause for the variable dental anomalies seen in patients with Ellis-van Creveld syndrome or Weyers acrodental dysostosis. PMID:23315474

Nakatomi, M; Hovorakova, M; Gritli-Linde, A; Blair, H J; MacArthur, K; Peterka, M; Lesot, H; Peterkova, R; Ruiz-Perez, V L; Goodship, J A; Peters, H

2013-03-01

127

Formation of polyelectrolyte complexes with diethylaminoethyl dextran: Charge ratio and molar mass effect.  

PubMed

The formation of polyelectrolyte complexes (PECs) between carboxymethyl pullulan and DEAE Dextran, was investigated, in dilute solution, with emphasis on the effect of charge density (molar ratio or pH) and molar masses. Electrophoretic mobility measurements have evidenced that insoluble PECs (neutral electrophoretic mobility) occurs for charge ratio between 0.6 (excess of polycation) and 1 (stoichiometry usual value) according to the pH. This atypical result is explained by the inaccessibility of some permanent cationic charge when screened by pH dependant cationic ones (due to the Hoffman alkylation). Isothermal titration calorimetry (ITC) indicates an endothermic formation of PEC with a binding constant around 10(5)Lmol(-1). Finally asymmetrical flow field flow fractionation coupled on line with static multi angle light scattering (AF4/MALS) evidences soluble PECs with very large average molar masses and size around 100nm, in agreement with scrambled eggs multi-association between various polyelectrolyte chains. PMID:25256478

Le Cerf, Didier; Pepin, Anne Sophie; Niang, Pape Momar; Cristea, Mariana; Karakasyan-Dia, Carole; Picton, Luc

2014-11-26

128

Routine antibiotic prophylaxis is not necessary during operations to remove third molars.  

PubMed

The purpose of this study was to evaluate the efficacy of antibiotic prophylaxis during removal of impacted third molars. We studied 150 patients with impacted mandibular or maxillary third molars who were divided randomly into three groups. The first was given amoxicillin 2g combined with clavulanic acid, orally daily for 5 days postoperatively; starting at the end of the operation. The second group was given the same drugs but the regimen started 5 days before the operation. The third was given no antibiotics. Pain, infection, swelling, alveolar osteitis, and interincisal mouth opening (mm) were evaluated. There were no significant differences among the groups in the incidence of these complications. We cannot recommend routine oral antibiotic prophylaxis in third molar surgery. PMID:17188409

Atao?lu, Hanife; Oz, Gülsün Yildirim; Candirli, Celal; Kizilo?lu, Dilek

2008-03-01

129

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

PubMed

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. PMID:24516829

Nayak, Gurudutt; Shetty, Shashit; Shekhar, Rhitu

2014-02-01

130

In-depth morphological study of mesiobuccal root canal systems in maxillary first molars: review  

PubMed Central

A common failure in endodontic treatment of the permanent maxillary first molars is likely to be caused by an inability to locate, clean, and obturate the second mesiobuccal (MB) canals. Because of the importance of knowledge on these additional canals, there have been numerous studies which investigated the maxillary first molar MB root canal morphology using in vivo and laboratory methods. In this article, the protocols, advantages and disadvantages of various methodologies for in-depth study of maxillary first molar MB root canal morphology were discussed. Furthermore, newly identified configuration types for the establishment of new classification system were suggested based on two image reformatting techniques of micro-computed tomography, which can be useful as a further 'Gold Standard' method for in-depth morphological study of complex root canal systems. PMID:23493453

Chang, Seok-Woo; Lee, Jong-Ki; Lee, Yoon

2013-01-01

131

Prevention of localized osteitis in mandibular third-molar sites using platelet-rich fibrin.  

PubMed

Purpose. To review our experience utilizing platelet rich fibrin (PRF), which is reported to aid in wound healing of extraction sites, for the prevention of localized osteitis following lower third-molar removal. Materials and Methods. PRF was placed in the mandibular third-molar extraction sites, 200 sites total, on 100 consecutive patients treated in our practice, by the authors. The patients were managed with standard surgical techniques, intraoperative IV antibiotic/steroid coverage, and routine postoperative narcotic analgesics/short-term steroid coverage. All patients were reevaluated for localized osteitis within 7-10 days of the surgery. A comparison group consisted of 100 consecutive patients who underwent bilateral removal of indicated mandibular wisdom teeth and did not receive PRF placement within the lower third molar surgical sites. Results. The incidence of localized osteitis (LO) following removal of 200 lower third molars with simultaneous PRF placement within the extraction site was 1% (2 sites out of 200). The group of patients whose mandibular 3rd molar sockets were not treated with PRF demonstrated a 9.5% (19 sites out of 200) incidence of localized osteitis. The latter group also required 6.5 hours of additional clinical time to manage LO than the study group who received PRF. Conclusions. This retrospective review demonstrated that preventative treatment of localized osteitis can be accomplished using a low cost, autogenous, soluble, biologic material, PRF, that PRF enhanced third-molar socket healing/clot retention and greatly decreased the clinical time required for postoperative management of LO. PMID:23653648

Hoaglin, Donald R; Lines, Gary K

2013-01-01

132

Long-Term Clinical Performance of Aesthetic Restorations in Primary Molars: A Case Report  

PubMed Central

There is a great diversity of restorative materials and techniques for deciduous molars with significant coronal destruction, including resin composite restorations and biologic restorations (portions of natural teeth). By using 4 evaluation methods, this study aimed at longitudinally evaluating the effectiveness of restorations in the deciduous molars of a patient having high caries activity, using adhesive techniques. The evaluation methods consisted of the fibre-optic transillumination method, clinical evaluation based on the United States Public Health Service criteria, radiographs, and an indirect method, scanning electron microscopy. Despite the patient's poor biofilm control, the restorative techniques were shown to be efficacious, particularly the biologic restorative technique. PMID:22567439

Pomarico, Luciana; Neves, Beatriz Goncalves; Maia, Lucianne Cople; Primo, Laura Guimaraes

2011-01-01

133

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

134

The molar enthalpies of solution and vapour pressures of saturated aqueous solutions of some ammonium salts  

Microsoft Academic Search

Vapour pressures of water over saturated solutions of ammonium bromide, ammonium dihydrogen phosphate, ammonium thiosulfate, ammonium persulfate, ammonium acetate, ammonium oxalate and ammonium tartrate were determined as a function of temperature. These vapour pressures were used to evaluate the water activities, osmotic coefficients and molar enthalpies of vaporization. Molar enthalpies of solution of ammonium bromide ?solHm(NH4Br, T=293.97K, m=0.1030mol·kg?1)=(17.4±0.5)kJ·mol?1; ammonium hydrogen

Alexander Apelblat; Eli Korin

2003-01-01

135

Nonsurgical Endodontic Retreatment of Maxillary Second Molar with Two Palatal Root Canals: A Case Report  

PubMed Central

Successful endodontic treatment requires thorough knowledge regarding each root canal system of any tooth and probability of extra canals should be considered. Second maxillary molar with two palatal root canals is not frequent and its incidence reported in literatures is about 0.4–2%. The present case report describes non-surgical retreatment of maxillary second mo-lar with two palatal root canals. Radiographic interpretation is difficult in this region; so, very careful examination of pulpal space and using supportive devices such as loupe and operating microscope is recommended to discover any unusual anat-omic features like extra canals. PMID:22991641

Eskandarinezhad, Mahsa; Ghasemi, Negin

2012-01-01

136

On the magnitude of border thickness in the partial molar volume of cavities in water  

NASA Astrophysics Data System (ADS)

Analysis of the partial molar volumes of large Lennard-Jones solutes in the TIP3P water model has shown that the border thickness is markedly larger than 0.5 Å [Biophys. Chem. 161 (2012) 46]. I confirm this result by analyzing the cavity partial molar volumes obtained by means of Monte Carlo simulations in the TIP4P water model [J. Phys. Chem. B 108 (2004) 16244]. It is argued that, very likely, these results are a consequence of some limitations/deficiencies of the water models used in computer simulations.

Graziano, Giuseppe

2013-05-01

137

A Comparative Evaluation of Hydroxyapatite Crystals and Glutaraldehyde as Agents for Pulpotomy in Deciduous Molars  

PubMed Central

Purpose: To evaluate and compare clinically and radiographically use of hydroxyapatite crystals and 2% glutaraldehyde as a pulpotomy agent. Method: Thirty deciduous molars were treated with pulpotomy using hydroxyapatite crystals and 2% glutaraldehyde. Results: Clinical and radiographic findings were observed at three months and six months. The success rate was found to be 100% clinically and 80.33% radiographically in the hydroxyapatite crystals group and 100% clinically and radiographically in the glutaraldehyde group. Clinical significance: The results of this study revealed that hydroxyapatite crystals is a potential pulpotomy agent for deciduous molars.

Adlakha, Vivek Kumar; Chandna, Preetika; Joshi, JL; Thomas, AM; Singh, Namita

2009-01-01

138

Negative urine pregnancy test in a molar pregnancy: is it possible?  

PubMed

A urine pregnancy test is commonly used to detect pregnancy and is based on finding intact ?-human chorionic gonadotrophin (hCG) molecules in the urine by an immunoassay system. However, the significantly large amount of ?-hCG in molar pregnancy may paradoxically lead to a false-negative result due to a phenomenon known as the 'high dose hook effect'. A case of molar pregnancy with negative urine pregnancy test but very high serum ?-hCG is reported. Every obstetrician should be aware of this limitation in the presence of a high index of suspicion of gestational trophoblastic disease but negative urine pregnancy test. PMID:25378114

Nigam, Aruna; Kumari, Archana; Gupta, Nidhi

2014-01-01

139

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

140

Excess molar volumes for CO sub 2 -CH sub 4 -N sub 2 mixtures  

SciTech Connect

Vibrating-tube densimetry experiments are being performed to determine the excess molar volumes of single-phase CO{sub 2}-CH{sub 4}-N{sub 2} gas mixtures at pressures as high as 3500 bars and temperatures up to 500{degrees}C. In our initial experiments, we determined the P-V-T properties of: (1) CO{sub 2}-CH{sub 4}, CO{sub 2}N{sub 2}, CH{sub 4}-N{sub 2}, and CO{sub 2}-CH{sub 4}-N{sub 2} mixtures at 1000 bars. 50 {degrees}C: and (2) CO{sub 2}-CH{sub 4} mixtures from 100 to 1000 bars at 100{degrees}C. Excess molar volumes in the binary subsystems are very accurately represented by two-parameter Margules equations. Experimentally determined excess molar volumes are in fair to poor agreement with predictions from published equations of state. Geometric projection techniques based on binary system data yield from published equations of state. Geometric projection techniques based on binary system data yield calculated excess molar volume for CO{sub 2}-CH{sub 4}-N{sub 2} mixtures that are in good agreement with our experimental data. 7 refs., 8 figs.

Seitz, J.C. (Oak Ridge National Lab., TN (United States) Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Geological Sciences); Blencoe, J.G.; Joyce, D.B. (Oak Ridge National Lab., TN (United States)); Bodnar, R.J. (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Geological Sciences)

1992-01-01

141

Use of the intraosseous screw for unilateral upper molar distalization and found well balanced occlusion  

Microsoft Academic Search

BACKGROUND: The aim of this study was to present a temporary anchorage device with intraosseous screw for unilateral molar distalization to make a space for the impacted premolar and to found well balanced occlusion in a case. CASE PRESENTATION: A 13-year-old male who have an impacted premolar is presented with skeletal Class I and dental Class 2 relationship. The screw

Ibrahim Erhan Gelgor; Ali Ihya Karaman; Tamer Buyukyilmaz

2006-01-01

142

[Dental health of first molars among Westphalian immigrants and German students].  

PubMed

The aim of this study was to assess the health status of the occlusal surface on the first molars of Westphalian students, of whom 41.0% were immigrants. The prevalence and retention of fissure sealants (FS) and caries experience was scored for 161 students aged 8 and 10 years. Logistic regression analysis was used to predict the influence of sex, ethnicity, and retention of FS on the occlusal caries risk of the first molars. There was no difference in caries prevalence and experience in 8-year-old German students and immigrants (5.6%/10.5%; 0.07 DMFT/0.21 DMFT), both parameters were significantly higher in 10-year-old immigrants than in German students (25.5%/9.5%; 0.55 DMFT/0.11 DMFT). The prevalence and number of molars with FS was not different between German students and immigrants at 8 years (39.1%, 1.28 FS; 33.8%, 0.94 FS) and at 10 years of age (47.4%, 1.68 FS; 39.4%, 1.17 FS). The occlusal caries risk of first molars without FS was significantly higher in 8-year-old immigrants than in German students (OR 4.62). FS should be used more frequently in daily dental practice. To improve the quality of FS, stricter implementation of guideline-based standards is required. PMID:24297452

Heinrich-Weltzien, R; Walther, M; Goddon, I; Kühnisch, J

2014-01-01

143

Surface Ultrastructure of Rat Molar Teeth after Experimentally Induced Erosion and Attrition  

Microsoft Academic Search

Young Osborne-Mendel rats were given different diets for 6 weeks. Effects of soft and rough food as well as acidic sport drink on the lingual surfaces of first mandibular molars were studied. In addition, the effect of fluoride on erosion was examined. A Jeol JSM-35 scanning electron microscope was used to visualize tooth surface ultrastructure. Intact surfaces were found in

R. Sorvari; A. Pelttari; J. H. Meurman

1996-01-01

144

Surgical Removal of Fractured Endodontic Instrument in the Periapex of Mandibular First Molar  

PubMed Central

The purpose of this article is to present the surgical removal of a broken endodontic file from the periapical region of the distal root of a mandibular first molar. The methods of diagnosis and measurement of the distance of the instrument to the adjacent vital structures in the periapical region was done with simple means and in an economical manner.

Gandevivala, Adil; Parekh, Bandish; Poplai, Gaurav; Sayed, Aliya

2014-01-01

145

What molars contribute to an emerging understanding of lateral enamel formation in Neandertals vs. modern humans  

Microsoft Academic Search

Two hypotheses, based on previous work on Neandertal anterior and premolar teeth, are investigated here: (1) that estimated molar lateral enamel formation times in Neandertals are likely to fall within the range of modern human population variation, and (2) that perikymata (lateral enamel growth increments) are distributed across cervical and occlusal halves of the crown differently in Neandertals than they

Debbie Guatelli-Steinberg; Donald J. Reid

2008-01-01

146

Molar Functional Relations and Clinical Behavior Analysis: Implications for Assessment and Treatment  

ERIC Educational Resources Information Center

The experimental analysis of behavior has identified several molar functional relations that are highly relevant to clinical behavior analysis. These include matching, discounting, momentum, and variability. Matching provides a broader analysis of how multiple sources of reinforcement influence how individuals choose to allocate their time and…

Waltz, Thomas J.; Follette, William C.

2009-01-01

147

Apical root resorption of maxillary first molars after intrusion with zygomatic skeletal anchorage.  

PubMed

The aim of this study was to evaluate radiographically the apical root resorption of maxillary first molars after their intrusion was done using zygomatic miniplates as skeletal anchorage in open-bite cases. The study group comprised 16 consecutively treated open-bite cases who had received special titanium miniplates in their zygomatic bones for use as anchorage to apply orthodontic intrusive forces to the maxillary posterior region. The control group consisted of 16 patients, who were matched regarding age, sex, and treatment duration but who had undergone fixed orthodontic treatment without intrusion mechanics for molars. Tooth lengths were measured on pretreatment, and posttreatment panoramic radiographs of all patients and mesiobuccal and distobuccal roots of left and right maxillary first molars were measured on-screen using a software program. The difference between the pre- and posttreatment tooth lengths was defined as apical root resorption. Comparison of the differences in root resorption of the two groups using the t-test for independent samples showed a statistically significant difference (P = .004) only for mesial roots on the right side. But because the mean difference in apical root resorption was only 0.5 mm, it was concluded that the apical root resorption of maxillary first molars after intrusion was done using zygomatic skeletal anchorage was not clinically significant. PMID:16283814

Ari-Demirkaya, Arzu; Masry, Mazin Al; Erverdi, Nejat

2005-09-01

148

Modern human molar enamel thickness and enamel--dentine junction shape  

E-print Network

, Box 571197, Washington, DC 20057-1197, USA Accepted 28 April 2006 Archives of Oral Biology (2006) 51 thickness; Enamel cap area; Dentine area; Enamel--dentine junction (EDJ) length; EDJ shape; Fossil hominids were generated from molars sectioned bucco- lingually across mesial cusps. Enamel cap area, dentine

Smith, Tanya M.

149

Passive drainage through the vestibular oblique incision in impacted inferior third molar surgery: a preliminary study.  

PubMed

The aim of the present study was to clinically evaluate the variables pain, swelling and trismus when two different suture techniques were applied in surgery of impacted lower third molars. The sample comprised 20 patients of both genders participating in the clinical trial at the Division of Oral and Maxillofacial Surgery, with an indication for the removal of bilaterally impacted lower third molars. They were divided into test and control groups. Complete suture was performed on the free and attached gums in the control group and only on the attached gum of the oblique vestibular incision in the test group. The results showed that the fact that the drainage of fluid through the suture was not obliterated led to diminution of pain 48 hours after surgery. No statistically significant differences were observed in relation to swelling, which diminished gradually in both groups. As regards the variable trismus, the test group presented a greater mouth opening throughout the evaluation, being statistically significant at 7 days. The probing depth, three months postoperatively, was found to be greater in the control group. This difference reached statistical significance for the vestibular distal region of the adjacent second molar. It is concluded that the strategy of not suturing the free gum of the oblique vestibular incision in the extraction of impacted lower third molars leads to the diminution of immediate painful symptomatology, but has no influence on the swelling. PMID:18841747

Xavier, Ruth Lopes de Freitas; Vasconcelos, Belmiro Cavalcanti do Egito; Caubi, Antonio Figuereido; Porto, Gabriela Granja; Maurette, Marvis Allais

2008-01-01

150

Partial molar volume reduction of solvent for solute crystallization using carbon dioxide as antisolvent  

Microsoft Academic Search

The gas antisolvent crystallization (GASC) process using dense carbon dioxide (CO2) as antisolvent is particularly useful for purification and micronization of thermo-labile bioactive solid substances. Conventionally, the GASC process is characterized by the relative total volume expansion or the relative molar volume expansion of the solution. A new criterion is proposed in this work in terms of the relative partial

Mamata Mukhopadhyay

2003-01-01

151

Effects of molar mass, concentration and thermodynamic conditions on polymer-induced flow drag reduction  

Microsoft Academic Search

Drag reduction in Taylor flow of polystyrene solutions is investigated using a commercial rheometer equipped with a standard double-gap sample holder with axial symmetry. The dependence of drag reduction on various factors, including polymer molar mass, polymer concentration, and thermodynamic conditions is studied. Drag reduction induced by polystyrene in toluene is found to increase with increasing polymer concentration in the

Torgeir Nakken; Morten Tande; Bo Nyström

2004-01-01

152

Bilateral fusion of mandibular second molars with supernumerary teeth: case report  

Microsoft Academic Search

Fusion is a developmental anomaly characterized by the union of two adjacent teeth. In this article we report a rare case of bilateral fusion of permanent mandibular second molars with supernumerary teeth. The rarity with which this entity appears, along with its complex characteristics, often make it difficult to treat. The endodontic management of one tooth is described, as well

Eduardo Nunes; Ivaldo Gomes de Moraes; Paulo Márcio de Oliveira Novaes; Simone Maria Galvão de Sousa

2002-01-01

153

Evaluating success of autotransplantation of embedded/impacted third molars harvested using piezosurgery: a pilot study.  

PubMed

Abstract Objective. To evaluate the success of autogenous transplantation of embedded/impacted third molars harvested using piezosurgery. Materials and methods. This prospective pilot study enrolled 20 healthy patients with non-restorable first/second molars and a caries-free retrievable embedded/impacted third molar. Piezosurgery was used for removing inter-radicular bone at the recipient socket as well as for bone removal around the donor teeth. Results. After an average follow-up of 16.4 months (SD = 1.9), 18 cases were successful with formation of periodontal ligament around the teeth. One tooth was lost due to infection at 1 month. One patient was lost to follow-up. There was no root resorption or ankylosis in any of the cases. In six donor teeth with complete root formation, root canal treatment was carried out. All the remaining teeth responded positively with vitality testing. Conclusion. Piezosurgery is an effective device if embedded/impacted third molars are to be harvested for successful autogenous transplantation. PMID:24791608

Nagori, Shakil Ahmed; Jose, Anson; Bhutia, Ongkila; Roychoudhury, Ajoy

2014-11-01

154

Transforming Growth Factor-? Isoform Expression in Mature Human Healthy and Carious Molar Teeth  

Microsoft Academic Search

Transforming growth factor (TGF)- isoforms have been implicated in cellular signalling during tooth development and repair, but little is known of their cellular localisation or distribution within the dental tissues in the mature tooth. This study investigated the presence of TGF-1, 2 and 3 isoforms in tissues of sound and carious human molar teeth, to understand better the expression of

A. J. Sloan; H. Perry; J. B. Matthews; A. J. Smith

2000-01-01

155

Genetic and Environmental Molarity and Modularity of Cognitive Functioning in 2-Year-Old Twins.  

ERIC Educational Resources Information Center

Investigated genetic and environmental influences on the similarity and differences among five tests of cognitive abilities in 1,958 pairs of same-sex twins born in 1994 in the United Kingdom. Results suggest a developmental trend from modularity to molarity when considered in relation to multivariate genetic results later in life that show that…

Petrill, Stephen A.; Saudino, Kimberly S.; Wilkerson, Bessie; Plomin, Robert

2001-01-01

156

Selenium:mercury molar ratios in bullfrog and leopard frog tadpoles from the northeastern United States.  

PubMed

Vertebrates experience adverse effects from methylmercury, largely obtained through their food. Selenium has the potential to reduce the toxic effects of methylmercury (and vice versa). In this paper, we examine the selenium:mercury molar ratios in tadpoles (Lithobates sphenocephalus, Lithobates catesbeianus (formerly Rana), and a newly documented leopard frog species currently referred to as R. sp. nov.) and fully formed leopard frog metamorphs. There were no significant differences in metal levels between the two leopard frog species, and data were therefore combined. Selenium:mercury molar ratios varied from 19 to 38 for bullfrog tadpoles, from 16 to 330 for leopard frog tadpoles, and from 7 to 17 for leopard frog metamorphs. Leopard frog tadpoles with less than 45 days exposure to field conditions had significantly higher molar ratios than other tadpoles and leopard frog metamorphs. There were significant locational differences for the molar ratios of bullfrogs, and leopard frog tadpoles with more than 45 days of field exposure. At the sites where we were able to sample both leopard frog tadpoles and leopard frog metamorphs, there were significant differences between the two distinct life stages. Most of the variation in the ratio was accounted for by selenium levels, field sites, and exposure period. PMID:24585386

Burger, Joanna; Feinberg, Jeremy; Jeitner, Christian; Gochfeld, Michael; Donio, Mark; Pittfield, Taryn

2014-06-01

157

Extension Rates and Growth in Tooth Height of Modern Human and Fossil Hominin Canines and Molars  

Microsoft Academic Search

The aim of this study was to describe similarities and differences in the way modern and fossil hominin teeth grow in height. Measurements from longitudinal ground sections of 7 modern human canines and 19 first permanent molars were used to calculate extension rates in the crowns and roots and to plot distance curves for growth in tooth height. These were

Christopher Dean

2009-01-01

158

Regaining leeway space and anterior crossbite correction with a modified maxillary molar distalizing appliance.  

PubMed

During the mixed dentition stage, adolescents experience rapid dental and skeletal development. Unfortunately, many of them do not visit the orthodontist early enough and miss out on the opportunity to take advantage of preventive and interceptive orthodontic treatment. This article describes the management of regaining leeway space and correcting anterior crossbite using a modified maxillary molar distalizing appliance. PMID:23855181

Park, J H; Tai, K; Ikeda, M; Kanao, A

2013-01-01

159

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. PMID:24790927

Kandaswamy, Deivanayagam; Jayaprakash, Nachimuthu

2014-01-01

160

Variation in hominoid molar enamel thickness Tanya M. Smith a,*, Anthony J. Olejniczak a  

E-print Network

Evolution 48 (2005) 575e592 #12;taxonomic discrimination using enamel thickness, tooth type and sectionVariation in hominoid molar enamel thickness Tanya M. Smith a,*, Anthony J. Olejniczak a , Lawrence.K. Received 25 August 2004; accepted 16 February 2005 Abstract Enamel thickness has figured prominently

Smith, Tanya M.

161

Study of the chemical nature of petroleum components of high molar mass from Russian fields  

Microsoft Academic Search

Study of the composition and structure of high molar mass compounds (HMC) of petroleum may be simplified considerably by fractionation before physical and chemical analysis. Solvent extraction, adsorption, gel-filtration, ion-exchange chromatography and other methods are applied to this end, the first two methods are most popular. The separation of resins by extraction is restricted as these petroleum components readily dissolve

T. A. Filimonova; L. V. Gorbunova; V. F. Kamyanov

1984-01-01

162

Femto-Molar Sensitive Field Effect Transistor Biosensors Based on Silicon Nanowires and  

E-print Network

Femto-Molar Sensitive Field Effect Transistor Biosensors Based on Silicon Nanowires and Antibodies-- This article presents electrically-based sensors made of high quality silicon nanowire field effect transistors characterizing the early stage of the diseases. Devices like field-effect transistors (FETs) can be suitable can

Dalang, Robert C.

163

Age at first molar emergence in early Miocene Afropithecus turkanensis and life-history evolution in the Hominoidea  

E-print Network

the life histories of fossil primate species. One method of determining age at first molar emergence is to determine the age at death of fossil individuals that were in the process of erupting their first molars enamel perikymata with estimates of the duration of cuspal enamel formation and the duration

Smith, Tanya M.

164

A modified device for intraoral radiography to assess the distal osseous defects of mandibular second molar after impacted third molar surgery  

PubMed Central

Purpose This article is to describe a modified device for intraoral radiography which was developed to obtain reproducible radiographic images for assessment of distal osseous defects of the mandibular second molar (2 Mm) after impacted third molar (3 Mm) surgery. Materials and Methods A commercial available alignment system for posterior region was modified by adding a reference gauge pin (millimetric) and threading a hollow acrylic cylinder at the ring of the radiographic positioner to attach the X-ray collimator. The design included customized resin acrylic stent for the occlusal surface of the 2Mm in maximum intercuspal position, individualizing the biteblock positioner. Periapical radiographs were taken before and after surgical extraction of 3 Mm, employing the radiographic technique of parallelism described by Kugelberg (1986) with this modified film holder and inserting the gauge pin on the deepest bone probing depth point. Results This technique permitted to obtain standardized periapical radiographs with a moderate to high resolution, repeatability, and accuracy. There was no difference between the measurements on the pre- and post-operative radiographs. This technique allowed better maintenance of the same geometric position compared with conventional one. The insertion of the gauge pin provided the same reference point and localized the deepest osseous defect on the two-dimensional radiographs. Conclusion This technique allowed better reproducibility in posterior radiographic records (distal surface of 2 Mm) and more accurate measurements of radiographic bone level by the use of a millimetric pin. PMID:22010068

Ana, Faria-Inocencio

2011-01-01

165

Molar Uprighting  

MedlinePLUS

... that this be done before a bridge or implant replaces the missing tooth. Preparation Before any treatment ... However, if you will be getting a dental implant, your dentist may want it put in before ...

166

Crystallization behavior of bisphenol-A polycarbonate: Effects of crystallization time, temperature, and molar mass  

NASA Astrophysics Data System (ADS)

Crystallization and multiple melting behavior of bisphenol-A polycarbonate (PC) was investigated using differential scanning calorimetry (DSC) for the monitoring of thermal behavior and atomic force microscopy (AFM) for the morphology study. The exceedingly slow crystallization kinetics of PC and the feasibility of obtaining near monodisperse fractions provide distinct advantages for the elucidation of the effects of crystallization time, temperature, and molar mass on crystallization kinetics. The effects of molar mass on the glass transition temperature (T g) and heat capacity change at Tg, and the amorphous density of PC were investigated. Similar to many semicrystalline polymers, PC exhibits a multiple melting behavior upon heating. While for each PC sample, the coexistence of low and high temperature endothermic regions in the DSC heating traces is explained by the melting of populations of crystals with different stabilities, melting-recrystallization-remelting effects are observed only for the lowest molar mass samples. The effects of crystallization temperature and molar mass distribution on overall crystallization kinetics were studied for some of the fractions, including the commercial PC-28K (Mw = 28,000 g.mol-1 ) sample. Regarding the kinetics of secondary crystallization, particular attention was placed on understanding the effects of molar mass, initial degree of crystallinity prior to the secondary crystallization, and secondary crystallization time and temperature. The secondary crystallization of PC follows the same laws discovered in previous studies of PEEK, PET, it-PS and ethylene copolymers, and the results are discussed in the context of a bundle-like secondary crystallization model. During isothermal annealing of semicrystalline PC-28K around the high melting endotherm, a significant increase of melting temperature along with peak broadening with time was observed. Independently, morphological studies using AFM showed that mean lamellar thickness increases with time during isothermal annealing. These results are discussed in light of isothermal thickening of lamellar crystals. Lastly, almost 200 DSC melting traces of varying molar mass PC samples thermally treated under various conditions were analyzed to calculate crystallinity (Xc), rigid fraction (RF), and rigid amorphous fraction (RAF). The correlation between RAF vs Xc, Tg, and Tg broadening are discussed.

Sohn, Seungman

167

Brodie bite with an extracted mandibular first molar in a young adult: a case report.  

PubMed

Total buccal crossbites are rare, but, when they occur, they can be extremely difficult to correct, even with surgery and orthodontics. In most patients with in-locking crossbites, the maxillary teeth erupt past their mandibular antagonists, creating severe occlusal difficulties. This article presents an adult patient with scissors-bite or partial telescoping bite bilaterally in the posterior region and an extracted mandibular first molar on the right side. She was treated with expansion of the mandibular arch, and the subsequent open bite was closed with the help of masticatory muscle exercises and high-pull headgear. The second and third molars were uprighted and moved mesially to close the extraction spaces. PMID:20451791

Chugh, Vinay K; Sharma, Vijay P; Tandon, Pradeep; Singh, Gyan P

2010-05-01

168

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. PMID:24987626

Al-Fraidi, Ahmad; Afify, Ahmed R.

2012-01-01

169

Unusual treatment of bimaxillary dentoalveolar protrusion via miniscrews and molar extraction.  

PubMed

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. PMID:24987626

Al-Fraidi, Ahmad; Afify, Ahmed R

2012-04-01

170

Molar Growth Yields of Certain Lactic Acid Bacteria as Influenced by Autolysis  

PubMed Central

Molar growth yields determined from batch cultures of Streptococcus diacetilactis and S. faecalis were appreciably greater at the peaks of maximal growth than after continued incubation and considerable autolysis. The higher molar growth yields were about equal to those determined in a continuous culture. Autolysis during logarithmic growth was minimal. The average Y value for adenosine triphosphate (ATP), determined by using limiting concentrations of glucose, galactose, lactose, and maltose for growing S. diacetilactis and limiting concentrations of glucose for growing S. lactis, S. cremoris, and S. faecalis, was 17.0. This is close to the Y (arginine) value of 17.8 determined with S. faecalis, but 62% greater than the generally accepted value of 10.5. Data are presented indicating that the often-used Y (ATP) value of 10.5 is erroneously low. PMID:4969603

Moustafa, Hassan H.; Collins, E. B.

1968-01-01

171

Aneurysmal bone cyst of maxilla with ectopic molar tooth - a case report.  

PubMed

Aneurysmal cysts of bone are rare non-neoplastic, locally aggressive lesion of bone with propensity for rapid growth, affecting mainly the long bones and spine. It rarely occurs in the head and neck region and within the head and neck mandible (especially the molar areas) is common. Aneurysmal cyst of bone involving the maxilla in the first decade of life is even rarer. We report a case of giant aneurysmal bone cyst of maxilla in eight-year-old male with ectopic molar tooth within the cyst. Is endoscopic excision possible? Endoscopic excision of the cyst was done successfully and no recurrence was noted even after 1 year of follow up. PMID:24238115

Verma, Roshan Kumar; Kumar, Ram; Bal, Amanjeet; Panda, Naresh K

2013-01-01

172

Radicular cyst associated with a primary first molar: A case report  

PubMed Central

Radicular cysts arising from deciduous teeth are rare. This report presents a case of radicular cyst associated with a primary molar following pulp therapy and discusses the relationship between pulp therapy and the rapid growth of the cyst. The treatment consisted of enucleation of the cyst sac and extraction of the involved primary teeth and 20 months follow up of the patient. Early diagnosis of the lesion would have lead to a less aggressive treatment plan. PMID:22509461

Toomarian, L.; Moshref, M.; Mirkarimi, M.; Lotfi, A.; Beheshti, M.

2011-01-01

173

Electrical Conductance of Fissure Enamel in Recently Erupted Molar Teeth as Related to Caries Status  

Microsoft Academic Search

Pit-and-fissure caries lesions contribute greatly to the caries incidence in permanent molar teeth in children. To date, the diagnosis of occlusal caries is still performed mainly by visual inspection, periodically aided by bite-wing radiography. However, in detecting small occlusal carious lesions, these methods perform inadequately, especially in low caries prevalence populations or individuals. The use of electrical conductance measurements (ECMs)

Y. L. Ie; E. H. A. M. Verdonschot; M. J. M. Schaeken; M. A. van’t Hof

1995-01-01

174

Study of transient photorefractive beam coupling in high- and low-molar-mass liquid crystal mixtures  

NASA Astrophysics Data System (ADS)

We observed transient signals of Bragg grating formation in high-performance photorefractive high- and low-molar-mass liquid crystal mixtures (HL-LCMs). These transient signals including oscillation-like behavior can be explained by a complex time constant in the case of a finite applied dc field. The time constant for the space-charge field to reach its steady state and the oscillation frequency are estimated.

Ono, H.; Kawatsuki, N.

175

Engineered Struvite Precipitation: lmpacts of Gomponent-lon Molar Ratios and pH  

Microsoft Academic Search

Struvite Fecipitation has the potential for rcmoving and recovering phosphorus from agricultural wastewater streams, such as concentrated animal feeding operations wastewater. However, impacts of anticipated component-ion molar ratios and potentially inter- fering ions are unknown as are the compounding pH relationship with respect to all potential complexes. This research expe.imentally investigates and mathematically models these facto.s. Emphasis is placed upon

Jun Wangl; Joel G. Burken; Rao Surampalli

176

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. PMID:22135686

Sortino, Francesco; Cicciu, Marco

2011-01-01

177

Maxillary Molar Extraction Decreases Stiffness of the Mandible in Ovariectomized Rats  

Microsoft Academic Search

Although osteoporosis is a major public health concern, the effect of this condition on oral bone has not been determined. Using the ovariectomized rat as a model, we examined whether acute estrogen depletion affects the mandible of the ovariectomized rat with and without maxillary molar extraction. Twenty-two ovariectomized and 20 sham-ovariectomized 90-day-old Sprague-Dawley rats were divided into the following groups:

R. P. Elovic; J. A. Hipp; W. C. Hayes

1994-01-01

178

Poly(4-vinylpyridine isopentyl bromide) as inhibitor for corrosion of pure iron in molar sulphuric acid  

Microsoft Academic Search

The effect of poly(4-vinylpyridine isopentyl bromide) (P4VPIPBr) in three degrees of quaternisation (6, 18 and 79%) on the corrosion of pure iron in molar sulphuric acid is investigated by potentiodynamic, polarisation resistance and weight loss measurements. The inhibition efficiency (E%) of P4VPIPBr increases with its concentration to attain ?100% around 5×10?6M. E% values obtained from the various methods are in

A Chetouani; K Medjahed; K. E Benabadji; B Hammouti; S Kertit; A Mansri

2003-01-01

179

A Clinical Trial of Pulpotomy vs. Root Canal Therapy of Mature Molars  

Microsoft Academic Search

Root canal therapy (RCT) and tooth extraction are the main treatment options for irreversible pulpitis or its sequelae. Pulpotomy is an alternative treatment; however, more evidence is required. If outcomes of pulpotomy with a calcium-enriched mixture (PCEM) are non-inferior for mature molars with irreversible pulpitis compared with those from one-visit RCT (ORCT), this may be a beneficial treatment option. Four

S. Asgary; M. J. Eghbal

2010-01-01

180

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

181

Glucose Degradation, Molar Growth Yields, and Evidence for Oxidative Phosphorylation in Streptococcus agalactiae  

PubMed Central

In a complex medium with the energy source as the limiting nutrient factor and under anaerobic growth conditions, Streptococcus agalactiae fermented 75% of the glucose to lactic acid and the remainder to acetic and formic acids and ethanol. By using the adenosine triphosphate (ATP) yield constant of 10.5, the molar growth yield suggested 2 moles of ATP per mole of glucose from substrate level phosphorylation. Under similar growth conditions, pyruvate was fermented 25% to lactic acid, and the remainder was fermented to acetic and formic acids. The molar growth yield suggested 0.75 mole of ATP per mole of pyruvate from substrate level phosphorylation. Under aerobic growth conditions about 1 mole of oxygen was consumed per mole of glucose; about one-third of the glucose was converted to lactic acid and the remainder to acetic acid, acetoin, and carbon dioxide. Molar growth yields indicated 5 moles of ATP per mole of glucose. Estimates based on products of glucose degradation suggested that about one-half of the ATP was derived from substrate level phosphorylation and one-half from oxidative phosphorylation. Addition of 0.5 m 2,4-dinitrophenol reduced the growth yield to that occurring in the absence of oxygen. Aerobic pyruvate degradation resulted in 30% of the substrate becoming reduced to lactic acid and the remainder being converted to acetic acid and carbon dioxide, with small amounts of formic acid and acetoin. The molar growth yields and products found suggested that 0.70 mole of ATP per mole of pyruvate resulted from substrate level phosphorylation and 0.4 mole per mole of pyruvate resulted from oxidative phosphorylation. PMID:4550679

Mickelson, M. N.

1972-01-01

182

C-Shaped Canal in Maxillary First Molars: A Case Report  

PubMed Central

C-shaped configuration in the upper maillary first molar is an extremely rare appearance (0.12%). This case reports management of the tooth with such a configuration as well as depiction of its internal morpholgy and external morphology through spiral computed tomography and dentascan in the contralateral tooth with similar morphology. After careful clinical observation and confirmation through spiral computed tomography, it was concluded that the teeth had Melton category I configuration with fused roots. PMID:24910684

Joshi, Chintan; Joshi, Surabhi

2014-01-01

183

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. PMID:23248457

Prasanth, T; Saraswathi, TR

2012-01-01

184

Molar mass of silicon highly enriched in 28Si determined by IDMS  

NASA Astrophysics Data System (ADS)

The molar mass of a new silicon crystal material highly enriched in 28Si ('Si28', x(28Si) >99.99%) has been measured for the first time using a combination of a modified isotope dilution mass spectrometry (IDMS) technique and a high resolution multicollector-ICP-mass spectrometer. This work is related to the redetermination of the Avogadro constant NA with an intended relative measurement uncertainty urel(NA) <= 2 × 10-8. The corresponding experimental investigations of the International Avogadro Coordination (IAC) were performed using this novel 'Si28' material. One prerequisite of the redetermination of NA is the determination of the isotopic composition and thus molar mass of 'Si28' with urel(M('Si28')) <= 1 × 10-8. At PTB, a molar mass M('Si28') = 27.976 970 27(23) g mol-1 has been determined with an associated relative uncertainty urel(M('Si28')) = 8.2 × 10-9, opening the opportunity to reach the target uncertainty of NA.

Pramann, Axel; Rienitz, Olaf; Schiel, Detlef; Schlote, Jan; Güttler, Bernd; Valkiers, Staf

2011-04-01

185

The use of resin-based composite restorations in pulpotomized primary molars.  

PubMed

The purpose of this retrospective clinical study was to report a 12- to 54-month follow-up, in which a resin-based composite filling material was used in direct contact with a fast-setting zinc oxide eugenol cement to restore the function and anatomy of 51 pulpotomized primary molars in 2- to 11-year-old children who needed a Class I or II restoration. Formocresol pulpotomy using Temrex cement was performed in all cases. The total-etch technique was used with: (1) 35% phosphoric acid; (2) OptiBond Solo Plus bonding agent; and (3) Filtek P60/shade B2 resin-based composite material. The restored teeth were sealed with Embrace pit and fissure sealant, monitored, and evaluated with periodic radiographs and clinical exams at 6-month recall visits. The results revealed that none of the 51 pulpotomized primary molars had evidence of periapical or furcation pathosis, recurrent decay, open margins, or broken restorations. In conclusion, this clinical study demonstrated that resin-based composite restorations--combined with the total-etch technique and a fifth-generation bonding agent and in direct contact with a fast-setting zinc oxide eugenol cement were long-lasting, quality clinical alternatives to restore the anatomy and function of pulpotomized primary molars. PMID:18477438

Caceda, Jorge H

2007-01-01

186

Molar absorptivity and color characteristics of acylated and non-acylated pelargonidin-based anthocyanins.  

PubMed

The effects of glycosylation and acylation on the spectral characteristics, molar absorptivity, and color attributes of purified acylated and non-acylated pelargonidin derivatives were compared. Pigments were obtained from strawberries, radishes, red-fleshed potatoes, and partially hydrolyzed radish pigments. Individual pigments were isolated by using semipreparative HPLC. Spectral and color (CIELch) attributes of purified pigments were measured. Molar absorptivity ranged from 15 600 to 39 590 for pelargonidin-3-glucoside (pg-3-glu) and pg-3-rutinoside-5-glucoside acylated with p-coumaric acid, respectively. The presence of cinnamic acid acylation had a considerable impact on spectral and color characteristics, causing a bathochromic shift of lambda(max). Sugar substitution also played an important role, with a hypsochromic shift caused by the presence of glycosylation. Pg-3, 5-diglu and pg-3,5-triglu possessed a higher hue angle (>40 degrees ) than the other pg derivatives at pH 1.0, corresponding to the yellow-orange region of the color solid. Acylation with malonic acid did not affect lambda(max) and showed little effect on color characteristics. The solvent system had an effect not only on the molar absorptivity, but also on the visual color characteristic of the pigments. PMID:10552862

Giusti, M M; Rodríguez-Saona, L E; Wrolstad, R E

1999-11-01

187

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. PMID:24932190

Gopinath, Vellore Kannan; Anwar, Khurshid

2014-01-01

188

Prevalence of Three-Rooted Mandibular First Molars among Indians Using SCT  

PubMed Central

Undetected extra roots or root canals are a major reason for failure of endodontic treatment. Failure to recognize an extra distolingual (DL) root in mandibular first molar may lead to incomplete debridement of the root canal system and eventually treatment failure. Therefore, it is crucial that atypical anatomy is identified before and during dental treatment. Spiral computed tomography (SCT) images can show 3D images, and therefore much detail can be used when traditional methods prevent adequate endodontic treatment. The overall incidence of DL roots on the mandibular first molars was 6.40% for all patients and 5.00% for all teeth, respectively. The occurrence of DL roots on the right side and on the left side showed a statistically significant difference. The bilateral incidence of symmetrical distribution of DL roots was 56.25%. The DL root canal orifice was separated from DB canal orifice by 2.79 ± 0.34?mm, from the MB canal orifice by 4.23 ± 0.81?mm, and from the ML canal orifice by 3.29 ± 0.52?mm. The high prevalence of the DL root in permanent mandibular first molars among the Indian population by using SCT and estimations of the interorifice distance of such teeth might be useful for successful endodontic treatments. PMID:23840212

Garg, Amit Kumar; Tewari, Rajendra Kumar; Agrawal, Neha

2013-01-01

189

Gross enamel hypoplasia in molars from subadults in a 16th-18th century London graveyard.  

PubMed

Dental Enamel Hypoplasia has long been used as a common nonspecific stress indicator in teeth from archaeological samples. Most researchers report relatively minor linear and pitted hypoplastic defects on tooth crown surfaces. In this work we report a high prevalence and early age of onset of extensive enamel defects in deciduous and permanent molars in the subadults from the post-medieval cemetery of Broadgate, east central London. Analysis of the dentition of all 45 subadults from the cemetery, using both macroscopic and microscopic methods, reveals disturbed cusp patterns and pitted, abnormal and arrested enamel formation. Forty-one individuals from this group (93.2%) showed some evidence of enamel hypoplasia, 28 of them showing moderate or extensive lesions of molars, deciduous or permanent (63.6% of the sample). Scanning Electron Microscope images reveal many molars with grossly deformed cuspal architecture, multiple extra cusps and large areas of exposed Tomes' process pits, where the ameloblasts have abruptly ceased matrix production, well before normal completion. This indented, rough and poorly mineralized surface facilitates both bacterial adhesion and tooth wear, and when such teeth erupt fully into the mouth they are likely to wear and decay rapidly. We suggest that this complex combination of pitted and plane-form lesions, combined with disruption of cusp pattern and the formation of multiple small cusps, should henceforth be identified as "Cuspal Enamel Hypoplasia." PMID:17492667

Ogden, A R; Pinhasi, R; White, W J

2007-07-01

190

Fabrication and characterization of ZnO nanowire structure on flexible substrate with different solution molarities  

NASA Astrophysics Data System (ADS)

Zinc Oxide nanostructures are capable of applying numerous applications such as optoelectronics, sensors, varistors, and electronic devices. There are several techniques to gorw ZnO nanostructures, including vapor-liquid-solid method, chemical vapor deposition, physical vapor deposition, metal organic chemical vapor deposition and solution process. Recently reported solution method is a simple way to grow ZnO nanowires at a low temperature. One distinctive advantage with the solution method is low processing temperature so that flexible polymer materials can be used as a substrate to grow ZnO nanowires. In this study, ZnO nanowires have been fabricated on PET film by solution method with various molarities to see the effect of different molarities on ZnO nanowire growth. The solution temperature was 80°C and ZnO nanowires were grown for 6 hours for each case. The ZnO seed layer was sputtered at room temperature for 33 min. prior to ZnO nanowire growth. These ZnO nanowires were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and photoluminescence (PL) measurements at room temperature using a He-Cd 325-nm laser as the excitation source. We also measured the current using current Atomic Force Microscopy (I-AFM) and presented the possibility to use ZnO nanowires as a power source for micro/nano scale devices. As a result, we found that the characterization of ZnO nanowires changes according to the solution molarity.

Lee, Kyu-Hang; Hur, Shin; Kim, Wan-Doo; Choi, Hongsoo

2010-08-01

191

Effects of early unilateral mandibular first molar extraction on condylar and ramal vertical asymmetry  

PubMed Central

Objective: The objective of the following study is to investigate the mandibular vertical asymmetry in a group of patients with early unilateral mandibular first molar extractions. Materials and Methods: Mandibular asymmetry index measurements (condylar, ramal and condylar-plus-ramal) were performed on the panoramic radiographs of a study group including 51 patients (mean age: 18.60 ± 1.11 years) and a control group of 51 patients (mean age: 18.53 ± 1.29 years). Group I included patients with a unilateral mandibular first molar extracted before the age of 12 years. Group II included patients with no extractions and had excellent Class I relationships, no missing teeth and slight or moderate anterior crowding. A paired t-test was used to determine possible statistically significant differences between the sides for the measurements. Student's t-test was used for the comparison of asymmetry index values between the groups and genders. Results: No group showed statistically significant sex-or side-specific differences for posterior vertical height measurements. Condylar asymmetry index and ramal asymmetry index measurements were not statistically different between the groups, while condylar-plus-ramal asymmetry index (CRAI) measurements were statistically different between the groups (P = 0.019). Conclusions: A slight difference for CRAI value was found in patients with early unilateral mandibular first molar extractions. PMID:24966767

Halicioglu, Koray; Celikoglu, Mevlut; Buyuk, Suleyman K.; Sekerci, Ahmet E.; Candirli, Celal

2014-01-01

192

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. PMID:24966737

Topkara, Ahu; Sari, Zafer

2013-01-01

193

Shape covariation between the craniofacial complex and first molars in humans.  

PubMed

The occurrence of mutual genetic loci in morphogenesis of the face and teeth implies shape covariation between these structures. However, teeth finalize their shape at an early age, whereas the face grows and is subjected to environmental influences for a prolonged period; it is therefore conceivable that covariation might modulate with age. Here we investigate the extent of this covariation in humans by measuring the 3D shape of the occlusal surface of the permanent first molars and the shape of the craniofacial complex from lateral radiographs, at two maturations stages. A sample of Greek subjects was divided into two groups (110 adult, 110 prepubertal) with equally distributed gender. The occlusal surfaces of the right first molars were 3D scanned from dental casts; 265 and 274 landmarks (including surface and curve semilandmarks) were digitized on the maxillary and mandibular molars, respectively. The corresponding lateral cephalometric radiographs were digitized with 71 landmarks. Geometric morphometric methods were used to assess shape variation and covariation. The vertical dimension of the craniofacial complex was the main parameter of shape variation, followed by anteroposterior deviations. The male craniofacial complex was larger (4.0-5.7%) and was characterized by a prominent chin and clockwise rotation of the cranial base (adult group only). Allometry was weak and statistically significant only when examined for the sample as a whole (percent variance explained: 2.1%, P = 0.0002). Covariation was statistically significant only between the lower first molar and the craniofacial complex (RV = 14.05%, P = 0.0099, and RV = 12.31%, P = 0.0162, for the prepubertal and adult groups, respectively). Subtle age-related covariation differences were noted, indicating that environmental factors may influence the pattern and strength of covariation. However, the main pattern was similar in both groups: a class III skeletal pattern (relative maxillary retrusion and mandibular protrusion), hyperdivergency, forward rotation of the posterior cranial base and upward rotation of the anterior cranial base were associated with mesiodistal elongation of the lower molars and height reduction of their distal cusps. This pattern mimics phylogeny in humans, where flexion and counterclockwise rotation of the cranial base, considered advantageous to survival, co-occur with tooth reductions that cannot be easily explained in evolutionary terms. The similarity of the phylogenetic and covariation patterns seems to support the pleiotropic gene hypothesis. PMID:24916927

Polychronis, Georgios; Halazonetis, Demetrios J

2014-08-01

194

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. PMID:23717333

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

2013-01-01

195

Partial molar volumes, expansibilities and compressibilities of glyglyglycine in aqueous sucrose and fructose solutions between 288.15 and 308.15 K  

Microsoft Academic Search

Apparent molar volumes (V?) and apparent molar adiabatic compressibilities (K?,s) of triglycine (glyglyglycine) in aqueous and mixed aqueous solutions of fructose and sucrose (2, 4, and 6mass%) have been determined at 288.15, 293.15, 298.15, 303.15, and 308.15K. From these data, limiting partial molar volumes (V?0) and limiting partial molar adiabatic compressibilities (K?,s0) for glyglyglycine in aqueous sucrose and fructose solutions

Amalendu Pal; Nalin Chauhan

2011-01-01

196

Endodontic management of maxillary first molar with seven root canals diagnosed using Cone Beam Computed Tomography scanning  

PubMed Central

The main objective of root canal treatment is thorough cleaning and shaping of the entire pulp space and its complete filling with an inert filling material. A major cause of post-treatment disease is the inability to locate, debride or adequately fill all canals of the root canal system. The form, configuration, and number of root canals in the maxillary first molars have been discussed for more than half a century. Maxillary first molars commonly present with three roots and three canals, with a second mesiobuccal canal (MB2) also present. With the advent of improved magnification there are reports of multiple root canals in the maxillary first molars. Nonsurgical endodontic therapy of a left maxillary first molar with three roots and seven root canals was successfully performed under a dental operating microscope. The diagnosis of multiple root canals was confirmed with the help of Cone Beam Computed Tomography (CBCT) images.

Raghavendra, Srinidhi Surya; Hindlekar, Ajit Narayan; Desai, Niranjan Nanasaheb; Vyavahare, Nishant Kishor; Napte, Bandu Devrao

2014-01-01

197

Implantation of an RFID-tag into human molars to reduce hard forensic identification labor. Part 2: Physical properties  

Microsoft Academic Search

Modifying and implanting existing RFID-tags into extracted human molars was described previously [P. Thevissen, G. Poelman, B. Puers, M. De Cooman, G. Willems, Implantation of RFID-tag into human molars to reduce hard forensic identification labor. Part 1. Working principle, Forensic Sci. Int. 156 (2006)]. Maximal vertical occlusal load during which the implanted RFID-tags remain active was evaluated in vitro. The

Patrick W. Thevissen; Guy Poelman; Michel De Cooman; Robert Puers; Guy Willems

2006-01-01

198

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

199

Characteristics of bony changes and tooth displacement in the mandibular cystic lesion involving the impacted third molar  

PubMed Central

Objectives The purpose of this retrospective study is to find the differentiating characteristics of cystic and cystic-appearing lesions that involve the impacted mandibular third molar by analyzing panoramic radiographs and computed tomography images, and to aid the preoperative diagnosis. Materials and Methods Eighty-one patients who had a mandibular cystic or cystic-appearing lesion that involved impacted mandibular third molar and underwent cyst enucleation were included in the study. The preoperative panoramic radiograph and computed tomography findings were analyzed in accordance to the histopathologic type. Results Most of the cystic lesions containing the mandibular third molar were diagnosed as a dentigerous cyst (77.8%). The occurrence of mesio-distal displacement of the third molar was more frequent in the odontogenic keratocyst (71.4%) and in the ameloblastoma (85.7%) than in the dentigerous cyst (19.1%). Downward displacement was primarily observed in each group. Odontogenic keratocyst and ameloblastoma showed more aggressive growth pattern with higher rate of bony discontinuity and cortical bone expansion than in dentigerous cyst. Conclusion When evaluating mandibular cystic lesions involving the impacted mandibular third molar, dentigerous cyst should first be suspected. However, when the third molar displacement and cortical bone absorption are observed, then odontogenic keratocyst or ameloblastoma should be considered. PMID:25368835

Lee, Jin-Hyeok; Kim, Sung-Min; Kim, Hak-Jin; Jeon, Kug-Jin; Park, Kwang-Ho

2014-01-01

200

Comparative studies between mice molars and incisors are required to draw an overview of enamel structural complexity  

PubMed Central

In the field of dentistry, the murine incisor has long been considered as an outstanding model to study amelogenesis. However, it clearly appears that enamel from wild type mouse incisors and molars presents several structural differences. In incisor, exclusively radial enamel is observed. In molars, enamel displays a high level of complexity since the inner part is lamellar whereas the outer enamel shows radial and tangential structures. Recently, the serotonin 2B receptor (5-HT2BR) was shown to be involved in ameloblast function and enamel mineralization. The incisors from 5HT2BR knockout (KO) mice exhibit mineralization defects mostly in the outer maturation zone and porous matrix network in the inner zone. In the molars, the mutation affects both secretory and maturation stages of amelogenesis since pronounced alterations concern overall enamel structures. Molars from 5HT2BR KO mice display reduction in enamel thickness, alterations of inner enamel architecture including defects in Hunter-Schreger Bands arrangements, and altered maturation of the outer radial enamel. Differences of enamel structure were also observed between incisor and molar from other KO mice depleted for genes encoding enamel extracellular matrix proteins. Thus, upon mutation, enamel analysis based exclusively on incisor defects would be biased. In view of the functional relationship between enamel structure and tooth morphogenesis, identification of molecular actors involved in amelogenesis requires comparative studies between mice molars and incisors. PMID:25285079

Goldberg, Michel; Kellermann, O.; Dimitrova-Nakov, S.; Harichane, Y.; Baudry, A.

2014-01-01

201

Unique inhibitory cascade pattern of molars in canids contributing to their potential to evolutionary plasticity of diet  

PubMed Central

Developmental origins that guide the evolution of dental morphology and dental formulae are fundamental subjects in mammalian evolution. In a previous study, a developmental model termed the inhibitory cascade model was established. This model could explain variations in relative molar sizes and loss of the lower third molars, which sometimes reflect diet, in murine rodents and other mammals. Here, I investigated the pattern of relative molar sizes (inhibitory cascade pattern) in canids, a taxon exhibiting a wide range of dietary habits. I found that interspecific variation in canid molars suggests a unique inhibitory cascade pattern that differs from that in murine rodents and other previously reported mammals, and that this variation reflects dietary habits. This unique variability in molars was also observed in individual variation in canid species. According to these observations, canid species have greater variability in the relative sizes of first molars (carnassials), which are functionally important for dietary adaptation in the Carnivora. In conclusion, an inhibitory cascade that differs from that in murine rodents and other mammals may have contributed to diverse dietary patterns and to their parallel evolution in canids. PMID:23467478

Asahara, Masakazu

2013-01-01

202

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. PMID:25089176

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

2014-01-01

203

Function of pretribosphenic and tribosphenic mammalian molars inferred from 3D animation.  

PubMed

Appearance of the tribosphenic molar in the Late Jurassic (160 Ma) is a crucial innovation for food processing in mammalian evolution. This molar type is characterized by a protocone, a talonid basin and a two-phased chewing cycle, all of which are apomorphic. In this functional study on the teeth of Late Jurassic Dryolestes leiriensis and the living marsupial Monodelphis domestica, we demonstrate that pretribosphenic and tribosphenic molars show fundamental differences of food reduction strategies, representing a shift in dental function during the transition of tribosphenic mammals. By using the Occlusal Fingerprint Analyser (OFA), we simulated the chewing motions of the pretribosphenic Dryolestes that represents an evolutionary precursor condition to such tribosphenic mammals as Monodelphis. Animation of chewing path and detection of collisional contacts between virtual models of teeth suggests that Dryolestes differs from the classical two-phased chewing movement of tribosphenidans, due to the narrowing of the interdental space in cervical (crown-root transition) direction, the inclination angle of the hypoflexid groove, and the unicuspid talonid. The pretribosphenic chewing cycle is equivalent to phase I of the tribosphenic chewing cycle, but the former lacks phase II of the tribosphenic chewing. The new approach can analyze the chewing cycle of the jaw by using polygonal 3D models of tooth surfaces, in a way that is complementary to the electromyography and strain gauge studies of muscle function of living animals. The technique allows alignment and scaling of isolated fossil teeth and utilizes the wear facet orientation and striation of the teeth to reconstruct the chewing path of extinct mammals. PMID:25091547

Schultz, Julia A; Martin, Thomas

2014-10-01

204

Effect of submucosal and intramuscular dexamethasone on postoperative sequelae after third molar surgery: comparative study.  

PubMed

We compared the effects of dexamethasone sodium phosphate given submucosally and intramuscularly on postoperative complications after removal of impacted lower third molars in a preliminary randomised prospective clinical trial. Thirty patients, each of whom required removal of a single impacted mandibular third molar under local anaesthesia, were randomly allocated to one of 3 groups of 10 each. The 2 experimental groups were given dexamethasone 4 mg submucosally or intramuscularly, and the control group had no steroid. Facial swelling and maximal interincisal distance were measured by an independent examiner at baseline (preoperatively), and at 1, 3, and 7 days postoperatively. Pain was measured by counting the number of rescue analgesic tablets taken, and from the patients' response to a visual analogue scale (VAS). The mean age of the 16 men and 14 women was 27 years (range 20-48). Both dexamethasone groups showed significant reductions in swelling (p<0.001) and in pain (p<0.05) compared with the control group at all intervals. Submucosal dexamethasone resulted in significantly less trismus than controls on day 1 postoperatively (p=0.04), but there were no significant differences among the groups at the other times. The effects of the two routes of dexamethasone were comparable for all variables. There were no cases of alveolar osteitis or wound infection. Dexamethasone 4 mg given submucosally is an effective way of minimising swelling, trismus, and pain after removal of impacted lower third molars, and is comparable with the intramuscular route. It offers a simple, safe, painless, non-invasive, and cost-effective treatment in moderate and severe cases. PMID:21035237

Majid, Omer Waleed; Mahmood, Waseem Khalid

2011-12-01

205

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. PMID:24688575

Shirvani, Armin; Hassanizadeh, Raheleh; Asgary, Saeed

2014-01-01

206

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. PMID:24750690

2014-01-01

207

Absolute silicon molar mass measurements, the Avogadro constant and the redefinition of the kilogram  

NASA Astrophysics Data System (ADS)

The results of an absolute silicon molar mass determination of two independent sets of samples from the highly 28Si-enriched crystal (AVO28) produced by the International Avogadro Coordination are presented and compared with results published by the Physikalisch-Technische Bundesanstalt (PTB, Germany), the National Research Council (NRC, Canada) and the National Metrology Institute of Japan (NMIJ, Japan). This study developed and describes significant changes to the published protocols for producing absolute silicon isotope ratios. The measurements were made at very high resolution on a multi-collector inductively coupled plasma mass spectrometer using tetramethylammonium hydroxide (TMAH) to dissolve and dilute all samples. The various changes in the measurement protocol and the use of TMAH resulted in significant improvements to the silicon isotope ratio precision over previously reported measurements and in particular, the robustness of the 29Si/30Si ratio of the AVO28 material. These new results suggest that a limited isotopic variability is present in the AVO28 material. The presence of this variability is at present singular and therefore its significance is not well understood. Fortunately, its magnitude is small enough so as to have an insignificant effect on the overall uncertainty of an Avogadro constant derived from the average molar mass of all four AVO28 silicon samples measured in this study. The NIST results confirm the AVO28 molar mass values reported by PTB and NMIJ and confirm that the virtual element-isotope dilution mass spectrometry approach to calibrated absolute isotope ratio measurements developed by PTB is capable of very high precision as well as accuracy. The Avogadro constant NA and derived Planck constant h based on these measurements, together with their associated standard uncertainties, are 6.02214076(19) × 1023 mol-1 and 6.62607017(21) × 10-34 Js, respectively.

Vocke, R. D., Jr.; Rabb, S. A.; Turk, G. C.

2014-10-01

208

Function of pretribosphenic and tribosphenic mammalian molars inferred from 3D animation  

NASA Astrophysics Data System (ADS)

Appearance of the tribosphenic molar in the Late Jurassic (160 Ma) is a crucial innovation for food processing in mammalian evolution. This molar type is characterized by a protocone, a talonid basin and a two-phased chewing cycle, all of which are apomorphic. In this functional study on the teeth of Late Jurassic Dryolestes leiriensis and the living marsupial Monodelphis domestica, we demonstrate that pretribosphenic and tribosphenic molars show fundamental differences of food reduction strategies, representing a shift in dental function during the transition of tribosphenic mammals. By using the Occlusal Fingerprint Analyser (OFA), we simulated the chewing motions of the pretribosphenic Dryolestes that represents an evolutionary precursor condition to such tribosphenic mammals as Monodelphis. Animation of chewing path and detection of collisional contacts between virtual models of teeth suggests that Dryolestes differs from the classical two-phased chewing movement of tribosphenidans, due to the narrowing of the interdental space in cervical (crown-root transition) direction, the inclination angle of the hypoflexid groove, and the unicuspid talonid. The pretribosphenic chewing cycle is equivalent to phase I of the tribosphenic chewing cycle, but the former lacks phase II of the tribosphenic chewing. The new approach can analyze the chewing cycle of the jaw by using polygonal 3D models of tooth surfaces, in a way that is complementary to the electromyography and strain gauge studies of muscle function of living animals. The technique allows alignment and scaling of isolated fossil teeth and utilizes the wear facet orientation and striation of the teeth to reconstruct the chewing path of extinct mammals.

Schultz, Julia A.; Martin, Thomas

2014-10-01

209

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

210

Radicular cyst followed by incomplete pulp therapy in primary molar: a case report.  

PubMed

Radicular cysts are one of the most common odontogenic cyst of the jaws. However, those arising from primary teeth are rare. An 8-year-old boy reported to the Department of Pedodontics and Preventive Dentistry with the chief complaint of pain and swelling on the lower left primary molar tooth region. Radiographic examination revealed a well-defined radiolucency with continuous hyperostotic border. Considering the age of the child, size of lesion, and involvement of unerupted premolars; marsupialization was preferred as a conservative treatment of choice. The success of the treatment was evident both clinically and radiographically during the follow-up period. PMID:24021332

Nagarathna, C; Jaya, A R; Jaiganesh, I

2013-01-01

211

Analysis of the internal anatomy of maxillary first molars by using different methods.  

PubMed

The success of endodontic treatment depends on the identification of all root canals so that they can be cleaned, shaped, and obturated. This study investigated internal morphology of maxillary first molars by 3 different methods: ex vivo, clinical, and cone beam computed tomography (CBCT) analysis. In all these different methods, the number of additional root canals and their locations, the number of foramina, and the frequency of canals that could or could not be negotiated were recorded. In the ex vivo study, 140 extracted maxillary first molars were evaluated. After canals were accessed and detected by using an operating microscope, the teeth with significant anatomic variances were cleared. In the clinical analysis, the records of 291 patients who had undergone endodontic treatment in a dental school during a 2-year period were used. In the CBCT analysis, 54 maxillary first molars were evaluated. The ex vivo assessment results showed a fourth canal frequency in 67.14% of the teeth, besides a tooth with 7 root canals (0.72%). Additional root canals were located in the mesiobuccal root in 92.85% of the teeth (17.35% could not be negotiated), and when they were present, 65.30% exhibited 1 foramen. Clinical assessment showed that 53.26%, 0.35%, and 0.35% of the teeth exhibited 4, 5, and 6 root canals, respectively. Additional root canals were located in this assessment in mesiobuccal root in 95.63% (27.50% could not be negotiated), and when they were present, 59.38% exhibited 1 foramen. CBCT results showed 2, 4, and 5 root canals in 1.85%, 37.05%, and 1.85% of the teeth, respectively. When present, additional canals showed 1 foramen in 90.90% of the teeth studied. This study demonstrated that operating microscope and CBCT have been important for locating and identifying root canals, and CBCT can be used as a good method for initial identification of maxillary first molar internal morphology. PMID:19249591

Baratto Filho, Flares; Zaitter, Suellen; Haragushiku, Gisele Aihara; de Campos, Edson Alves; Abuabara, Allan; Correr, Gisele Maria

2009-03-01

212

[Preparation and properties of prostaglandin D2 labelled with tritium with high molar radioactivity].  

PubMed

Kinetic parameters of enzymatic and non-enzymatic transformations of [3H]prostaglandin H2 (PGH2) were determined; the maximum yield of [3H]PGD2 being obtained at the keobs/koobs ratio equal to 10. The two-stage enzymatic synthesis of [3H]PGD2 with high molar radioactivity (3.15 TBq/mmol) from [3H]arachidonic acid carried out. Its identity in properties to the natural PGD2 was shown in experiments on the inhibition of ADP-induced aggregation of thrombocytes and on enzymatic oxidation with 15-hydroxyprostaglandin dehydrogenase. PMID:2590255

Shram, S I; Vrzheshch, P V; Bobrovich, O A; Tatarintsev, A V; Shevchenko, V P; Miasoedov, N F

1989-09-01

213

Dentigerous cyst associated with ectopic maxillary third molar in maxillary antrum  

PubMed Central

The treatment of ectopic maxillary tooth is surgical removal via a Caldwell-Luc procedure. Trans-nasal extraction of tooth may be attempted if the tooth is small and sited near the maxillary antrum. It is also mandatory to completely remove all pathological antral tissue and thoroughly assess all resected soft tissue histologically. This is important as certain antral pathologies such as dentigerous cyst, as in this case, may co-exist with an ectopic molar. It is thus important to follow-up such patients. In the absence of any unusual histology, surgery provides the patient with a definitive cure of his symptoms. PMID:22696724

Thakur, Gagan; Nair, Preeti P; Thomas, Shaji; Ahuja, Ruchi; Kothari, Rohit

2011-01-01

214

Treatment of dentoskeletal bimaxillary protrusion: additional extraction of maxillary second molars.  

PubMed

This case report describes the orthodontic treatment of an 18-year-old female patient with Class II malocclusion with dentoskeletal bimaxillary protrusion. An acceptable treatment result was obtained with a four first premolar extraction and an additional maxillary two second molar extraction plan. Standard edgewise appliances were placed after the premolars were extracted. A positive soft tissue response to treatment was achieved, and the patient's profile was improved, with a reduction of lip protrusion and mentalis strain. Dentally, the interincisal angle improved significantly as both the maxillary and mandibular incisors were uprighted after space closure. The occlusion remained stable during 2 years of follow-up. PMID:19639455

Iijima, Shigeki; Yoshida, Mitsuru; Terada, Kazuto

2009-07-01

215

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

216

Coronectomy of a lower third molar in combination with vital pulp therapy  

PubMed Central

Coronectomy is a procedure that intentionally spares the vital root after removal of the crown of the lower third molar to avoid damage to the inferior alveolar nerve. Vital pulp therapy is one option for managing exposed pulp tissue to reduce the risk of pulpal inflammation or necrosis. Among various dental materials, mineral trioxide aggregate (MTA) has been successfully used for vital pulp therapy. Thus, this case report discusses a coronectomy procedure in combination with vital pulp therapy using MTA. This case also attempts to highlight the formation of tertiary dentin, evidence of successful vital pulp therapy. PMID:25202226

Kim, Young-Bin; Joo, Woo-Hee; Min, Kyung-San

2014-01-01

217

Background factors of molar-incisor hypomineralization in a group of Finnish children.  

PubMed

Abstract Objective. Molar-Incisor Hypomineralization (MIH) is a common developmental enamel defect characterized by demarcated opacities in permanent molars and incisors. Its etiology still remains unclear. The aim of this retrospective cohort study was to assess if the socioeconomic environment of the child is associated with MIH. Materials and methods. The study was located in two rural towns and three urban cities in Finland. A total of 818 children, between 7-13 years old, were examined for MIH using the evaluation criteria in line with those of the European Academy of Paediatric Dentistry, but excluding opacities smaller than 2 mm in diameter. The mothers filled in a questionnaire which included questions related to the family's way of living (e.g. area of residency, farming, day care attendance) and socioeconomic status (family income, number of mother's school years, level of maternal education). Results. The prevalence of MIH in the study population was 17.1%. Family income, urban residency and day care attendance were associated with MIH in the univariate analysis. In the multivariate analysis using binary logistic regression, only urban residency during a child's first 2 years of life remained associated with MIH. The prevalence of MIH in urban areas was 21.3% and in rural areas 11.5% (OR = 2.18, CI = 1.35-3.53, p = 0.001). Conclusions. The prevalence of MIH was related to urban residency and could not be explained by any other factor included in the study. PMID:25005624

Wuollet, Emma; Laisi, Sakari; Salmela, Eija; Ess, Anneli; Alaluusua, Satu

2014-11-01

218

Expression of Nfic during root formation in first mandibular molar of rat.  

PubMed

The transcription factor Nfic is a key regulator during tooth development. Nfic deficient mice exhibit short and abnormal molar roots and severely deformed incisors. Dental epithelial cells, known as Hertwig's epithelial root sheath (HERS), participate in root formation. However, whether Nfic is involved in HERS-mesenchyme interaction remains unclear. In this study, the detail temporal and spatial expression pattern of Nfic during rat molar development was examined using immunohistochemistry and in situ hybridization. Nfic was detected in ameloblasts, dental follicle cells (DFCs) and dental papilla cells (DPCs), especially the DPCs close to dentin, from postnatal day 5 to day 16. Nfic expression in DPCs, DFCs and HERS cells was also examined by western blot and RT-PCR. Nfic was detected in DPCs and DFCs, but not in HERS cells. Co-culture experiment further indicated that Nfic mRNA expression in DPCs was elevated by the presence of HERS cells. Our results revealed that Nfic could be a marker gene for root odontoblasts differentiation initiation and its expression might be regulated through epithelial-mesenchymal interaction. PMID:25074584

Chen, Xiang; Chen, Guoqing; Feng, Lian; Jiang, Zongting; Guo, Weihua; Yu, Mei; Tian, Weidong

2014-12-01

219

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. PMID:24966776

Yildiz, Esma; Tosun, Gul

2014-01-01

220

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 PMID:24884684

2014-01-01

221

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. PMID:24995239

Patil, Swapnil N; Kamble, Seema D; Mowade, Tushar; Motghare, Pavan

2014-01-01

222

Molar Incisor Hypomineralization: A Study of Prevalence and Etiology in a Group of Iranian Children  

PubMed Central

Objective The aim of this study was to investigate the prevalence of molar incisor hypomineralization (MIH) and its relationship with systemic conditions in a group of Iranian children. Methods The study population comprised of 433 7-9 year olds, from four schools in Zahedan, Iran. Subjects were evaluated clinically by one examiner, and at a separate session, their mothers completed a coded medical history questionnaire. Hypo-mineralized molars and incisors were recorded based on DDE (developmental defects of enamel) index and DMFT (number of decayed, filled and missing teeth) was determined. Statistical analyses were performed using Chi-square and independent sample t-tests. Findings Fifty-five (12.7%) children showed MIH. The overall mean number of affected teeth was 0.2. The mean value of DMFT in MIH children was greater than in normal children. Demarcated opacities were the most frequent (76%) enamel defect. Mother's and child's medical problems during prenatal, perinatal and post natal period were significantly remarkable in MIH children. Conclusion The prevalence of MIH in a group of Iranian children was 12.7%. Prenatal, perinatal and post natal medical conditions were more prevalent in children affected by MIH. PMID:23056894

Ahmadi, Rahil; Ramazani, Nahid; Nourinasab, Rahmatollah

2012-01-01

223

Comparison of oral versus sublingual piroxicam during postoperative pain management after lower third molar extraction.  

PubMed

In this study, 53 patients received piroxicam, administered orally or sublingually, after undergoing removal of symmetrically positioned lower third molars, during two separate appointments. This study used a randomized, blind, cross-over protocol. Objective and subjective parameters were recorded for comparison of postoperative results for 7 days after surgery. Patients treated with oral or sublingual piroxicam reported low postoperative pain scores. The patients who received piroxicam orally took a similar average amount of analgesic rescue medication compared with patients who received piroxicam sublingually (p>0.05). Patients exhibited similar values for mouth opening measured just before surgery and immediately following suture removal 7 days later (p>0.05), and showed no significant differences between routes of piroxicam administration for swelling control during the second or seventh postoperative days (p>0.05). In summary, pain, trismus and swelling after lower third molar extraction, independent of surgical difficulty, could be controlled by piroxicam 20mg administered orally or sublingually and no significant differences were observed between the route of delivery used in this study. PMID:21144709

Trindade, P A K; Giglio, F P M; Colombini-Ishikiriama, B L; Calvo, A M; Modena, K C S; Ribeiro, D A; Dionísio, T J; Brozoski, D T; Lauris, J R P; Faria, F A C; Santos, C F

2011-03-01

224

Risk factors in the occurrence of molar-incisor hypomineralization amongst a group of Iraqi children.  

PubMed

BACKGROUND.? Despite the worldwide increasing interest in the prevalence studies of molar-incisor hypomineralization (MIH), there is still insufficient evidence to verify the aetiological factors of this condition. AIMS.? To investigate risk factors involved in the development of MIH in a group of school-aged Iraqi children. DESIGN.? Seven- to nine-year-old school children (823 of 1000 eligible, response rate of 82.3%) had their first permanent molars and incisors evaluated using the European Academy of Paediatric Dentistry evaluation criteria for MIH. Mothers completed a medical history questionnaire-based interview performed in the schools by a trained examiner. RESULTS.? For children with MIH, 6% reported no relevant medical history; the remaining 94% reported various medical conditions putatively associated with MIH compared with 70% for the non-affected group. Post-natal medical conditions (33.3%) were most frequently reported. When data were split into the possible risk effect groups, maternal psychological stress (OR, 3.24), frequent exposure to ultrasonic scans during the last gestational trimester (OR, 2.51) and birth order as a fourth sibling or later (OR, 3.17 and 5.73, respectively) were previously unreported significant risk factors and postulated as contributing to, or causing the defect. CONCLUSIONS.? Children with MIH had experienced a greater number of medical conditions than their unaffected peers with no single health event identified as a risk factor. PMID:22646757

Ghanim, Aghareed; Manton, David; Bailey, Denise; Mariño, Rodrigo; Morgan, Michael

2013-05-01

225

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

226

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

227

Growth-Associated Changes in the Periodontal Bone and Molar Teeth of Male Rats  

PubMed Central

Here we report quantitative data associating periodontal bone variables of young conventional rats with the growth process. The hemimandibles of male rats (IIM/Fm stock, 2 to 15 wk of age.) were excised and submitted to conventional morphologic, radiologic, and histologic evaluation. The length, area, or X-ray absorbance of various regions or structures was measured on digital images of radiographs by using an image-analysis program. The sum of periodontal bone areas undergoing resorption (interproximal + intraradicular) increased until 9 or 10 wk of age and decreased thereafter. Mineral accretion rates and mineral density asymptotes were not significantly different among molars. The mineral density of resorption areas in alveolar bone fitted sinusoidal kinetics, indicative of the ‘instability’ of the tissue due to its high metabolic activity. Mineral accretion rates and mineral density asymptotes were not significantly different among molars. The proportion of root length within alveolar bone exhibited a biphasic curve (minimum at 5 wk of age), due to differences in the growth rates of variables involved in its calculation (distance between the cementoenamel junction to the apex and height of the resorption areas). The distance between the cementoenamel junction and alveolar bone crest over time fitted a sigmoidal function with a point of inflection that did not differ significantly from that of body or mandible dry weight. In summary, the growth process appears to affect periodontal bone support and the distance between the cementoenamel junction and alveolar bone crest in male rats. PMID:19807966

Garcia, Maria F; Moreno, Hilda; Rigalli, Alfredo; Puche, Rodolfo C

2009-01-01

228

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. PMID:23524859

Pontual, Andrea dos Anjos; Beltrão, Rejane Targino; Beltrão, Ricardo Villar; Pontual, Maria Luiza dos Anjos

2013-01-01

229

Obtaining Spruce Hemicelluloses of Desired Molar Mass by using Pressurized Hot Water Extraction.  

PubMed

There is growing interest in utilizing galactoglucomannan, the main hemicellulose in softwoods, for various applications such as cosmetics, pharmaceuticals, textiles, alimentary, and health products, as well as for the production of fuels. For fuel production and for using the rare sugars as platform chemicals, the hemicelluloses need to be hydrolyzed to sugar monomers, and for this purpose, low-molecular-mass extracts are favorable. However, for the other applications high molecular masses are required, which presents an even greater challenge for extraction. The ability to optimize the extraction process according to the needs of further processing, by using solely water as the solvent, is a key issue in the environmentally friendly utilization of this versatile raw material. The goal of this work is to study how the average molar mass of hemicelluloses extracted from spruce sapwood can be influenced by altering the experimental conditions. The main parameters influencing the extraction and hydrolysis of the hemicelluloses, namely, extraction time, temperature, pH, and chip size, were studied. The results show that it is feasible to develop an extraction process for harvesting spruce hemicelluloses, also of large molar masses, for industrial applications by using pressurized hot water extraction. PMID:25169811

Rissanen, Jussi V; Grénman, Henrik; Xu, Chunlin; Willför, Stefan; Murzin, Dmitry Yu; Salmi, Tapio

2014-10-01

230

The vasculogenesis--a possible histological identification criterion for the molar pregnancy.  

PubMed

The benign hydatidiform mole (partial and complete) practically represents an associated pathology of the first trimester miscarriage; it is considered that it represents the initial pathology, which, evolutionally, may be followed by the appearance of invasive mole and choriocarcinoma. The authors have studied clinical and cytogenetical 61 cases selected according to some specific criteria for the suspicion of molar pregnancy or hydropic abortion and 21 cases that represented the control group made by patients with normal pregnancy which have been presented for legal abortion. In all cases has been made a histological exam and has been studied the vasculogenesis by immunohistochemistry labeling for CD31 and CD34. Following-up the results has been established a number of histological and immunohistochemical criteria for the evaluation and differentiation of various molar pregnancy types and the vasculogenesis characteristics. The most important differential diagnosis criteria between partial and complete mole is represented by the trophoblast disposition and the atypical trophoblast in the complete mole. PMID:21424033

Novac, Liliana; Niculescu, Mihaela; Manolea, Maria Magdalena; Iliescu, D; Georgescu, Claudia Valentina; Com?nescu, Al; Cernea, N; Enache, Andreea

2011-01-01

231

Effect of Erythrina mulungu on anxiety during extraction of third molars  

PubMed Central

Objectives: The aim of the present study was to evaluate the effect of Erythrina mulungu on the control of dental anxiety in patients who had under gone bilateral extraction of asymptomatic, impacted mandibular third molars. Material and Methods: In a randomized, double-blind, crossover study, 30 healthy volunteers (5 men and 25 women, over 18 years of age), received either 500mg of E.mulungu (Mulungu Matusa®) or 500 mg of placebo, p.o., one hour before surgical procedure. The level ofanxiety was assessed through questionnaire sand physical parameters, such as blood pressure, heart rate andoxygen saturation. Data were analyzed by Chi-square test, ANOVA (Tukey test) and Friedman with significance level of 5%. Results: A higher preference (Chi-square, p = 0.0062) for E. mulungu was observed for both genders. Volunteers with higher anxiety levels tended to to prefer E. mulungu. No statistically significant differences were verified in blood pressure (one-way ANOVA, p = 0.1259), heart rate (Friedman, p> 0.05) and oxygen saturation (Friedman, p = 0.7664) among periods and types of treatments. Conclusions: E. mulungu showed an anxiolytic effect without significant changes in physiological parameters. It could be considered as an alternative to control the anxiety in adult patients undergoing mandibular thirdmolars surgery. Key words:Anxiety, Erythrina mulungu, third molar, oral surgery. PMID:24880443

Silveira-Souto, Maria L.; Sao-Mateus, Carla R.; Groppo, Francisco C.

2014-01-01

232

On a relationship between molecular polarizability and partial molar volume in water  

NASA Astrophysics Data System (ADS)

We reveal a universal relationship between molecular polarizability (a single-molecule property) and partial molar volume in water that is an ensemble property characterizing solute-solvent systems. Since both of these quantities are of the key importance to describe solvation behavior of dissolved molecular species in aqueous solutions, the obtained relationship should have a high impact in chemistry, pharmaceutical, and life sciences as well as in environments. We demonstrated that the obtained relationship between the partial molar volume in water and the molecular polarizability has in general a non-homogeneous character. We performed a detailed analysis of this relationship on a set of ~200 organic molecules from various chemical classes and revealed its fine well-organized structure. We found that this structure strongly depends on the chemical nature of the solutes and can be rationalized in terms of specific solute-solvent interactions. Efficiency and universality of the proposed approach was demonstrated on an external test set containing several dozens of polyfunctional and druglike molecules.

Ratkova, Ekaterina L.; Fedorov, Maxim V.

2011-12-01

233

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

234

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. PMID:23112949

Jang, Sook-Yoon; Kim, Minji

2012-01-01

235

Selenium:Mercury Molar Ratios in Freshwater Fish from Tennessee: Individual, Species, and Geographical Variations have Implications for Management  

PubMed Central

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.

2014-01-01

236

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

237

Economic modeling of sealing primary molars using a "value of information" approach.  

PubMed

The objective was to evaluate 2 primary molar sealant strategies for publicly insured children using an "expected value of perfect information" (EVPI) approach. We converted a 10,000-observation tooth-level cost-effectiveness simulation model comparing 2 primary molar sealant strategies - always seal (AS) and standard care (SC) - with a 1,250-observation child-level model. Costs per child per restoration or extraction averted were estimated. Opportunity losses under the AS strategy were determined for children for whom SC was the optimal choice. We determined the EVPI by multiplying mean opportunity losses by the projected incident population of publicly insured 3-year-olds in the US over 10 years with costs discounted at 2%. All analyses were conducted under assumptions of high and low intrachild correlations between at-risk teeth. The AS strategy cost $43.68 over SC (95% CI: -$5.50, $92.86) per child per restoration or extraction averted under the high intrachild correlation assumption and $15.54 (95% CI $7.86, $23.20) under the low intrachild correlation. Under high intrachild correlation, mean opportunity losses were $80.28 (95% CI: $76.39, $84.17) per child, and AS was the optimal strategy in 31% of children. Under low correlation, mean opportunity losses were $14.61 (95% CI: $12.20, $17.68) and AS was the optimal strategy in 87% of children. The EVPI was calculated at $530,813,740 and $96,578,389 (for high and low intrachild correlation, respectively), for a projected total incident population of 8,059,712 children. On average, always sealing primary molars is more effective than standard care, but widespread implementation of this preventive approach among publicly insured children would result in large opportunity losses. Additional research is needed to identify the subgroups of publicly insured children who would benefit the most from this effective and potentially cost-saving public health intervention. PMID:25056993

Ney, J P; van der Goes, D N; Chi, D L

2014-09-01

238

Removal of impacted third molars by oral/maxillofacial surgery and general dentistry residents.  

PubMed

The post-operative symptoms of patients who had undergone third molar extractions by Oral/Maxillofacial Surgery (OMS) residents were compared with those of patients whose extractions were performed by General Dentistry (GD) residents. The OMS group had more extractions per visit and were more likely to use intravenous sedation than the GD-treated group. No significant differences were found when the provider groups were compared by post-operative symptoms such as osteitis, infection, trismus, or paresthesia/dysthesia. The pain relief due to postoperative analgesics during the immediate 12-hour period was higher for patients treated by GD residents. Multiple regression analysis revealed that this difference was due to the number of teeth extracted and the complexity of the surgical procedure, independent of type of provider. PMID:8153854

Handelman, S L; Black, P M; Desjardins, P; Gatlin, L; Simmons, L

1993-01-01

239

High-performance photorefractivity in high- and low-molar-mass liquid crystal mixtures  

NASA Astrophysics Data System (ADS)

High-performance photorefractivity in a thick-grating regime was observed in high- (H-LC) and low-molar-mass liquid crystal (L-LC) mixtures (HL-LCMs) doped with fullerene. The photorefractive performance strongly depended on the concentration ratio of H-LC and L-LC. A high net gain coefficient over 600 cm-1 was achieved with low applied dc fields (0.7 V/?m) and a fringe spacing of 2.8 ?m. The gain coefficients and the resolution increased with increasing the concentration of the H-LCs. The photorefractive grating formation time was varied between 0.12 and 3.5 s, which depended on the concentration of the H-LCs.

Ono, Hiroshi; Kawatsuki, Nobuhiro

1999-03-01

240

Excess molar enthalpies of an alkanol + a cyclic ether at 298.15 K  

SciTech Connect

Excess molar enthalpies H{sub m}{sup E} measured at 298.15 K using a flow calorimeter are reported for 12 mixtures of methanol, ethanol, propan-1-ol, or propan-2-ol + tetrahydrofuran (THF), + tetrahydropyran (THP), or + 1,4-dioxane. For all of the systems investigated, H{sub m}{sup E} is strongly positive over the whole mole fraction range and increase in the order methanol

Letcher, T.M.; Govender, U.P. [Univ. of Natal, Durban (South Africa). Dept. of Chemistry and Applied Chemistry

1995-09-01

241

Effect of mandibular molar anatomy on the buccal Class I cavity preparation.  

PubMed

In mandibular molars, enamel dramatically increases in thickness at the buccal pit area and progresses occlusally due to an extensive concavity in the buccal dentinal core. In order to comply with the principles of operative dentistry, this anatomic variance dictates that, if the ultimate restoration is to be placed in dentin, the axial wall of a Class I buccal pit preparation should incline medially rather than follow the external contour of the tooth. The occlusal cavosurface angle of the preparation should be obtuse to coincide with enamel rod direction. Retention, when needed, should be placed at the mesio-axial and disto-axial line angles to avoid undermining occlusal intercuspal enamel, especially as the preparation approaches 2 mm occlusal to the buccal pit. PMID:6348113

Re, G J; Pruitt, D; Childers, J M; Norling, B K

1983-09-01

242

Raman studies of hydration of hydroxy complexes and the effect on standard partial molar heat capacities  

NASA Astrophysics Data System (ADS)

Raman spectroscopic studies of aqueous hydroxy complexes B(OH) 3, B(OH) 42-, Al(OH) 4-, Zn(OH) 42-, and their deuterated analogues provide compelling evidence for the presence of strong hydrogen bonding of water in the outer solvation sphere to the oxygen of the hydroxy ligand in the first coordination sphere. The deuterated complexes are more strongly hydrogen bonded than the hydrogen complexes. The fact that these hydrogen-bonding effects for the hydroxy borates are much more pronounced than for the aluminate and zincate anions can account for the unexpectedly large differences in the standard partial molar heat capacities of B(OH) 4- and A1(OH) 4-. The extension of semi-empirical solvation models based on the Born approximation for aqueous hydrolyzed species will need to consider the rather large and specific effect of hydrogen bonding of water to the hydroxide ion.

Brooker, Murray H.; Tremaine, Peter R.

1992-06-01

243

Partial molar enthalpies and reaction enthalpies from equilibrium molecular dynamics simulation  

NASA Astrophysics Data System (ADS)

We present a new molecular simulation technique for determining partial molar enthalpies in mixtures of gases and liquids from single simulations, without relying on particle insertions, deletions, or identity changes. The method can also be applied to systems with chemical reactions. We demonstrate our method for binary mixtures of Weeks-Chandler-Anderson particles by comparing with conventional simulation techniques, as well as for a simple model that mimics a chemical reaction. The method considers small subsystems inside a large reservoir (i.e., the simulation box), and uses the construction of Hill to compute properties in the thermodynamic limit from small-scale fluctuations. Results obtained with the new method are in excellent agreement with those from previous methods. Especially for modeling chemical reactions, our method can be a valuable tool for determining reaction enthalpies directly from a single MD simulation.

Schnell, Sondre K.; Skorpa, Ragnhild; Bedeaux, Dick; Kjelstrup, Signe; Vlugt, Thijs J. H.; Simon, Jean-Marc

2014-10-01

244

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. PMID:24723307

Rager, Timo

2014-06-01

245

Molar Functional Relations and Clinical Behavior Analysis: Implications for Assessment and Treatment  

PubMed Central

The experimental analysis of behavior has identified several molar functional relations that are highly relevant to clinical behavior analysis. These include matching, discounting, momentum, and variability. Matching provides a broader analysis of how multiple sources of reinforcement influence how individuals choose to allocate their time and offers an empirical rationale for reducing problem behavior by increasing adaptive behavior. Discounting highlights the functional relations that affect self-control. Momentum specifies the variables responsible for persistence in challenging situations. Variability characterizes a functional dimension of behavior that is essential for learning and problem solving. These concepts have important implications for clinical practice and research. A selective review of these concepts is presented, and their implications for assessment and treatment are discussed with two goals: to inform basic scientists about the relevance of their work and to invite clinical behavior analysts to broaden the conceptual basis for their work. PMID:22478513

Waltz, Thomas J; Follette, William C

2009-01-01

246

Partial molar enthalpies and reaction enthalpies from equilibrium molecular dynamics simulation.  

PubMed

We present a new molecular simulation technique for determining partial molar enthalpies in mixtures of gases and liquids from single simulations, without relying on particle insertions, deletions, or identity changes. The method can also be applied to systems with chemical reactions. We demonstrate our method for binary mixtures of Weeks-Chandler-Anderson particles by comparing with conventional simulation techniques, as well as for a simple model that mimics a chemical reaction. The method considers small subsystems inside a large reservoir (i.e., the simulation box), and uses the construction of Hill to compute properties in the thermodynamic limit from small-scale fluctuations. Results obtained with the new method are in excellent agreement with those from previous methods. Especially for modeling chemical reactions, our method can be a valuable tool for determining reaction enthalpies directly from a single MD simulation. PMID:25318729

Schnell, Sondre K; Skorpa, Ragnhild; Bedeaux, Dick; Kjelstrup, Signe; Vlugt, Thijs J H; Simon, Jean-Marc

2014-10-14

247

Demineralization of Enamel in Primary Second Molars Related to Properties of the Enamel  

PubMed Central

Enamel structure is of importance in demineralization. Differences in porosity in enamel effect the rate of demineralization, seen between permanent and deciduous teeth. Individual differences have been shown in the mean mineral concentration values in enamel, the role of this in demineralization is not thoroughly investigated. The aim of this study was to study variations of depths of artificial lesions of demineralization and to analyze the depth in relation to variations in the chemical and mineral composition of the enamel. A demineralized lesion was created in second primary molars from 18 individuals. Depths of lesions were then related to individual chemical content of the enamel. Enamel responded to demineralization with different lesion depths and this was correlated to the chemical composition. The carbon content in sound enamel was shown to be higher where lesions developed deeper. The lesion was deeper when the degree of porosity of the enamel was higher. PMID:22629152

Sabel, N.; Robertson, A.; Nietzsche, S.; Norén, J. G.

2012-01-01

248

Demineralization of enamel in primary second molars related to properties of the enamel.  

PubMed

Enamel structure is of importance in demineralization. Differences in porosity in enamel effect the rate of demineralization, seen between permanent and deciduous teeth. Individual differences have been shown in the mean mineral concentration values in enamel, the role of this in demineralization is not thoroughly investigated. The aim of this study was to study variations of depths of artificial lesions of demineralization and to analyze the depth in relation to variations in the chemical and mineral composition of the enamel. A demineralized lesion was created in second primary molars from 18 individuals. Depths of lesions were then related to individual chemical content of the enamel. Enamel responded to demineralization with different lesion depths and this was correlated to the chemical composition. The carbon content in sound enamel was shown to be higher where lesions developed deeper. The lesion was deeper when the degree of porosity of the enamel was higher. PMID:22629152

Sabel, N; Robertson, A; Nietzsche, S; Norén, J G

2012-01-01

249

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. PMID:25031600

Parirokh, Masoud; V. Abbott, Paul; Yosefi, Mohammad Hosein; Hosseini, Hamid Reza

2014-01-01

250

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

251

Amoxicillin and clavulanic acid vs ceftazidime in the surgical extraction of impacted third molar: a comparative study.  

PubMed

The objective of this work is to compare the effectiveness and the side effects of two different drugs, amoxicillin and clavulanic acid vs ceftazidime, used as antibiotic prophylaxis in the surgical extraction of third molars and to demonstrate that the use of second choice antibiotic has no significant advantages in comparison with a first choice antibiotic. One hundred and seven patients with impacted third molar were selected and divided into two groups: amoxicillin and clavulanic acid were administered to group 1 and ceftazidime to group 2 for five days after surgery and we observed the postoperative period. The statistical analysis showed no differences between the two groups which lead to the conclusion that there is no indication to routinely administrate intramuscular second-choice antibiotic prophylatic therapy (ceftazidime) in case of surgical extraction of the third molar. PMID:23058029

Sisalli, U; Lalli, C; Cerone, L; Maida, S; Manzoli, L; Serra, E; Dolci, M

2012-01-01

252

A comparison of the effects of methylprednisolone and tenoxicam on pain, edema, and trismus after impacted lower third molar extraction  

PubMed Central

Background The aim of the present study was to compare the effects of preemptive intravenous tenoxicam and methylprednisolone administrations on extraction of impacted third molars. Material/Methods This was a placebo-controlled, randomized, double-blind, clinical trial. A total of 60 adult patients ages 18–40 years with the complaints of impacted third molar teeth were included in the study. Results The postoperative swelling ratios (p<0.05) and pain scores (p<0.05) were significantly better in both study groups than in the control group and there was no statistically significant difference between methylprednisolone and tenoxicam groups with regards to the edema and pain relief. Conclusions Preoperative administration of 80 mg methylprednisolone achieves better control of trismus than tenoxicam without any significant differences in edema and pain control in impacted third molar teeth extraction. PMID:24473372

Ilhan, Ozgur; Agacayak, Kamil Serkan; Gulsun, Belgin; Koparal, Mahmut; Gunes, Nedim

2014-01-01

253

SOLUBILITY OF MUSTARD GAS [BIS (?-CHLOROETHYL) SULFIDE] IN WATER, MOLAR SODIUM CHLORIDE, AND IN SOLUTIONS OF DETERGENTS  

PubMed Central

1. The solubility of mustard (H) in water and in molar sodium chloride was found to be 5.8 x 10–3 molar and 3.2 x 10–3 molar respectively or 0.92 mg. per ml. and 0.5 mg. per ml. Solubility curves have been drawn and the usefulness of this method in examining the homogeneity of H preparations as well as in establishing their solubility, is discussed. 2. Certain detergents increase the solubility of H in water. The solubility was found to increase with the concentration of detergent. 3. Many detergents were found to affect the interfacial tension between H and water so that with slight agitation liquid H breaks up into minute droplets. This in turn greatly accelerates the rate of solution. PMID:19873510

Herriott, Roger M.

1947-01-01

254

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

255

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

256

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. PMID:22589580

Kirzioglu, Zuhal; Gungor, Ozge Erken; Ciftci, Z. Zahit

2011-01-01

257

Practice-based clinical evaluation of metal-ceramic and zirconia molar crowns: 3-year results.  

PubMed

This practice-based study evaluates the clinical performance of conventionally luted metal-ceramic and zirconia molar crowns fabricated with pronounced anatomical core design and a prolonged cooling period of the veneering porcelain. Fifty-three patients were treated from 07/2008 until 07/2009 with either metal-ceramic crowns (MCC) (high-noble alloy + low-fusing porcelain) or zirconia crowns (Cercon System, DeguDent, Germany). Forty-nine patients (30 women/19 men) with 100 restorations (metal-ceramic: 48/zirconia: 52, mean observational period: 36·5 ± 6 months) participated in a clinical follow-up examination and were included in the study. Time-dependent survival (in situ criteria), success (event-free restorations) and chipping rates (defects of the veneering ceramics) were calculated according to the Kaplan-Meier method and analysed in relation to the crown fabrication technique, using a Cox regression model (P < 0·05). Three complete failures (metal-ceramic: 1, zirconia: 2) were recorded (survival rate after 3 years: metal-ceramic: 97·6%, zirconia: 95·2%). Of the metal-ceramic restorations, 90·9% remained event-free (two ceramic fractures, one endodontic treatment), whereas the success rate for the zirconia was 86·8% (two ceramic fractures, one endodontic treatment, one secondary caries). No significant differences in survival (P = 0·53), success (P = 0·49) and ceramic fracture rates (P = 0·57) were detected. The combination of a pronounced anatomical core design and a modified firing of the veneering porcelain for the fabrication of zirconia molar crowns resulted in a 3-year survival, success and chipping rate comparable to MCC. PMID:23211063

Rinke, S; Schäfer, S; Lange, K; Gersdorff, N; Roediger, M

2013-03-01

258

[The method of esthetic crown restoration with composite resin jacket crown in primary molars].  

PubMed

The term "esthetics" has recently been also used in the dental field, and a field called esthetic dentistry is increasingly being noted. The number of not only adult but also pediatric patients who visit for treatment aiming at esthetic recovery is being increased. Inpedodontics, composite resin of the coronal color is generally used in the restoration of deciduous incisors. However, the method using metal crowns for the deciduous teeth is used for the deciduous molars at present. We applied a composite resin jacket crown to the deciduous molar in a way similar to that of esthetic crown restoration for the anterior teeth. The surgical procedure before crown preparation varied slightly according to the presence or absence of pulpal treatment of vital teeth and with non-vital teeth, but the application was performed as follows: 1) Desensitization of pulp, pulpal treatment and core construction. 2) Preparation of crown. 3) Selection, trial set and occlusal equilibration of a metal crown for the deciduous tooth. 4) Precision impression with a silicone impression material. 5) Removal of the metal crown for the deciduous tooth from the impression material. 6) Making of an under-cut to the abutment tooth on the buccal lingual side. 7) Filling of the impression with chemical polymerization resin. 8) Application of pressure in the oral cavity. 9) Adjustment of edge and crown forms. Thus, the preparation method for the composite resin jacket crown was relatively simple. Since this surgery, the patient has been followed up for 1 year and 6 months, and no specifically troublesome points have been observed clinically. The patient and her parents are satisfied with the results.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2134806

Doi, K; Shibui, N; Suda, M; Uehara, M; Karibe, H; Kondou, K

1990-10-01

259

Dental pulp of the third molar: a new source of pluripotent-like stem cells.  

PubMed

Dental pulp is particularly interesting in regenerative medicine because of the accessibility and differentiation potential of the tissue. Dental pulp has an early developmental origin with multi-lineage differentiation potential as a result of its development during childhood and adolescence. However, no study has previously identified the presence of stem cell populations with embryonic-like phenotypes in human dental pulp from the third molar. In the present work, we describe a new population of dental pulp pluripotent-like stem cells (DPPSCs) that were isolated by culture in medium containing LIF, EGF and PDGF. These cells are SSEA4(+), OCT3/4(+), NANOG(+), SOX2(+), LIN28(+), CD13(+), CD105(+), CD34(-), CD45(-), CD90(+), CD29(+), CD73(+), STRO1(+) and CD146(-), and they show genetic stability in vitro based on genomic analysis with a newly described CGH technique. Interestingly, DPPSCs were able to form both embryoid-body-like structures (EBs) in vitro and teratoma-like structures that contained tissues derived from all three embryonic germ layers when injected in nude mice. We examined the capacity of DPPSCs to differentiate in vitro into tissues that have similar characteristics to mesoderm, endoderm and ectoderm layers in both 2D and 3D cultures. We performed a comparative RT-PCR analysis of GATA4, GATA6, MIXL1, NANOG, OCT3/4, SOX1 and SOX2 to determine the degree of similarity between DPPSCs, EBs and human induced pluripotent stem cells (hIPSCs). Our analysis revealed that DPPSCs, hIPSC and EBs have the same gene expression profile. Because DPPSCs can be derived from healthy human molars from patients of different sexes and ages, they represent an easily accessible source of stem cells, which opens a range of new possibilities for regenerative medicine. PMID:22467856

Atari, Maher; Gil-Recio, Carlos; Fabregat, Marc; García-Fernández, Dani; Barajas, Miguel; Carrasco, Miguel A; Jung, Han-Sung; Alfaro, F Hernández; Casals, Nuria; Prosper, Felipe; Ferrés-Padró, Eduard; Giner, Luis

2012-07-15

260

Low PIP(2) molar fractions induce nanometer size clustering in giant unilamellar vesicles.  

PubMed

Phosphatidylinositol (4,5) bisphosphate (PIP2) is an important signaling molecule located on the inner leaflet of the cell membrane. In order to perform its various signaling functions, it is suggested that PIP2 must be able to form localized clusters. In this study, we have used LAURDAN generalized polarization function (GP) with unlabeled PIP2 and single point fluorescence correlation spectroscopy and brightness analysis of various BODIPY labeled PIP2 to determine the presence of clusters in the membrane of giant unilamellar vesicles (GUVs) made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) or a mixture of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), sphingomyelin and cholesterol. We determined the number of freely diffusing fluorescent BODIPY molecules in the membrane and found that in GUVs containing various amounts of labeled PIP2, this number was significantly lower than in GUVs made with the control BODIPY labeled hexadecyl phosphatidylcholine (BODIPY-HPC). Also, we noted an increase in brightness of the labeled PIP2 particles with increasing labeled PIP2 molar fraction. Together with the observed change in LAURDAN GP with increasing molar fraction of unlabeled PIP2, these results demonstrate the presence of PIP2 enriched clusters that are smaller than the resolution limit of the fluorescent microscope. In addition, we report the presence of a hypsochromic shift of the fluorescence for the BODIPY labeled lipids that we attributed to clustering. This clustering result in a change in the partitioning of the lipids with the BODIPY labeled PIP2 lipids able to move between the liquid ordered and liquid disordered phase. PMID:24269375

Salvemini, Iyrri L; Gau, D M; Reid, J; Bagatolli, L A; Macmillan, A; Moens, P D J

2014-01-01

261

Volume analysis of heat-induced cracks in human molars: A preliminary study  

PubMed Central

Context: Only a few methods have been published dealing with the visualization of heat-induced cracks inside bones and teeth. Aims: As a novel approach this study used nondestructive X-ray microtomography (micro-CT) for volume analysis of heat-induced cracks to observe the reaction of human molars to various levels of thermal stress. Materials and Methods: Eighteen clinically extracted third molars were rehydrated and burned under controlled temperatures (400, 650, and 800°C) using an electric furnace adjusted with a 25°C increase/min. The subsequent high-resolution scans (voxel-size 17.7 ?m) were made with a compact micro-CT scanner (SkyScan 1174). In total, 14 scans were automatically segmented with Definiens XD Developer 1.2 and three-dimensional (3D) models were computed with Visage Imaging Amira 5.2.2. The results of the automated segmentation were analyzed with an analysis of variance (ANOVA) and uncorrected post hoc least significant difference (LSD) tests using Statistical Package for Social Sciences (SPSS) 17. A probability level of P < 0.05 was used as an index of statistical significance. Results: A temperature-dependent increase of heat-induced cracks was observed between the three temperature groups (P < 0.05, ANOVA post hoc LSD). In addition, the distributions and shape of the heat-induced changes could be classified using the computed 3D models. Conclusion: The macroscopic heat-induced changes observed in this preliminary study correspond with previous observations of unrestored human teeth, yet the current observations also take into account the entire microscopic 3D expansions of heat-induced cracks within the dental hard tissues. Using the same experimental conditions proposed in the literature, this study confirms previous results, adds new observations, and offers new perspectives in the investigation of forensic evidence. PMID:25125923

Sandholzer, Michael A.; Baron, Katharina; Heimel, Patrick; Metscher, Brian D.

2014-01-01

262

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. PMID:24967595

Alam, Mohammad Khursheed; Hamza, Muhammad Asyraf; Khafiz, Muhammad Aizuddin; Rahman, Shaifulizan Abdul; Shaari, Ramizu; Hassan, Akram

2014-01-01

263

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. PMID:24797658

2014-01-01

264

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. PMID:24570827

M. Badr-Eldin, Shaimaa; A. Ahmed, Tarek; R Ismail, Hatem

2013-01-01

265

Comparative evaluation of Ferric Sulfate, Electrosurgical and Diode Laser on human primary molars pulpotomy: an “in-vivo” study  

PubMed Central

Background and aims: Despite modern advances in the prevention of dental caries and increased understanding of the importance of maintaining the natural primary dentition, many teeth are still lost prematurely. This can lead to malocclusion with aesthetic, phonetic and functional problems that may be transient or permanent. Therefore, maintaining the integrity and health of the oral tissues is the primary objective of pulp treatment. Pulpotomy has remained an acceptable and mainstay treatment in preserving the vitality of primary tooth and prolonging its life till the permanent successor erupts. Various materials and techniques are available for pulpotomy on primary molars; all with some advantages and disadvantages. The present study was carried out on 45 primary molars to evaluate and compare the clinical and radiographic success of diode laser, electrosurgical and ferric sulfate pulpotomy over a period of 9 months. Materials (Subjects) and Methods: The forty five primary molars were randomly and equally divided into three treatment groups which were as follows: Group A: 15 primary molars treated with 15.5% Ferric sulfate Group B: 15 primary molars treated with electrosurgical unit and Group C: 15 primary molars treated with diode laser. All teeth in three categories were followed up clinically and radiographically at 1, 3, 6 and 9 months post treatment and the findings were recorded on the prepared proforma Results: Clinically, 86.6% success rate was found in ferric sulfate group whereas 100% success rate was found in electrosurgical and diode laser groups. Radiographically, 80% success rate was found in all the three groups at the end of 9 months with internal resorption being the most common cause of failure after pulpotomy. Conclusions: Thus, electrosurgery and diode lasers appear to be acceptable alternative to pharmacotherapeutic pulpotomy agents. PMID:24771970

Yadav, P; Indushekar, KR; Saraf, BG; Sheoran, N; Sardana, D

2014-01-01

266

Conservative treatment of complicated oblique crown-root fractures of molars: a report of five representative cases.  

PubMed

The five cases presented here describe a conservative treatment procedure for complicated crown-root fractures of molars with extensive loss of tooth structure. After the mobile crown-root fragments were extracted, the remaining crowns were restored at the juxtagingival level. The follow-up time ranged from two years, seven months, to four years. At the follow-up examinations, all of the teeth were asymptomatic and had healthy clinical appearances. There was no evidence of pockets related to fractures. The results of these cases show that complete periodontal healing is possible with conservative treatment of complicated crown-root fracture of molars. PMID:23418876

Wang, P; He, W; Ni, L; Lu, Q; Sun, H

2013-01-01

267

Endodontic Management of a Maxillary First Molar with Two Palatal Canals and a Single Buccal Canal: A Case Report  

PubMed Central

Thorough knowledge of root canal morphology is essential for the endodontic therapy. There are rare variations in canal number and configuration in maxillary molars, which could affect treatment outcome. This paper presents the endodontic management of a maxillary first molar with two palatal canals in one root (Vertucci type IV) and a single buccal canal. In this paper cone-beam computed tomography was made to asses this morphology. This paper is intended to reinforce clinician's awareness of the rare morphology of root canals. PMID:23304564

Atash biz Yeganeh, Leila; Adel, Mamak; Vahedi, Reza; Tofangchiha, Maryam

2012-01-01

268

Effect of age, impaction types and operative time on inflammatory tissue reactions following lower third molar surgery  

Microsoft Academic Search

Background  Postoperative mobidity following third molar surgery is affected by a number of factors. The study of these factors is essential\\u000a for effective planning and limitation of morbidity. The aim of this study was to determine the effect of age, type of impaction\\u000a and operative time on immediate postoperative tissue reactions following mandibular third molar surgery.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Consecutive patients with impacted mandibular

Seidu A Bello; Wasiu L Adeyemo; Babatunde O Bamgbose; Emeka V Obi; Ademola A Adeyinka

2011-01-01

269

Excess molar volumes, viscosity, refractive index, and Gibbs energy of activation of binary biodiesel + benzene, and biodiesel + toluene mixtures at 298.15 and 303.15 K  

Microsoft Academic Search

Excess molar volumes (V\\u000a E), viscosities, refractive index, and Gibbs energies were evaluated for binary biodiesel + benzene and toluene mixtures at\\u000a 298.15 and 303.15 K. The excess molar volumes V\\u000a E were determined from density, while the excess Gibbs free energy of activation G*E was calculated from viscosity deviation ??. The excess molar volume (V\\u000a E), viscosity deviation (??),

Ufuk Sancar Vural; Fatih Durmaz; Ozcan Kocyigit; Hasan Kocyigit; V. Muradoglu; Beril Akin

2008-01-01

270

Excess molar volumes for CO{sub 2}-CH{sub 4}-N{sub 2} mixtures  

SciTech Connect

Vibrating-tube densimetry experiments are being performed to determine the excess molar volumes of single-phase CO{sub 2}-CH{sub 4}-N{sub 2} gas mixtures at pressures as high as 3500 bars and temperatures up to 500{degrees}C. In our initial experiments, we determined the P-V-T properties of: (1) CO{sub 2}-CH{sub 4}, CO{sub 2}N{sub 2}, CH{sub 4}-N{sub 2}, and CO{sub 2}-CH{sub 4}-N{sub 2} mixtures at 1000 bars. 50 {degrees}C: and (2) CO{sub 2}-CH{sub 4} mixtures from 100 to 1000 bars at 100{degrees}C. Excess molar volumes in the binary subsystems are very accurately represented by two-parameter Margules equations. Experimentally determined excess molar volumes are in fair to poor agreement with predictions from published equations of state. Geometric projection techniques based on binary system data yield from published equations of state. Geometric projection techniques based on binary system data yield calculated excess molar volume for CO{sub 2}-CH{sub 4}-N{sub 2} mixtures that are in good agreement with our experimental data. 7 refs., 8 figs.

Seitz, J.C. [Oak Ridge National Lab., TN (United States)]|[Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Geological Sciences; Blencoe, J.G.; Joyce, D.B. [Oak Ridge National Lab., TN (United States); Bodnar, R.J. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Geological Sciences

1992-04-01

271

Abstract Rodents have a toothless diastema region be-tween the incisor and molar teeth which may contain ru-  

E-print Network

Abstract Rodents have a toothless diastema region be- tween the incisor and molar teeth which may of diastema teeth represents a natural "experi- ment" which can be compared to the loss of teeth in gene knockout experiments. All teeth, regardless of shape or identity, pass through the same developmental

Jernvall, Jukka

272

GEOPHYSICAL RESEARCH LETTERS, VOL. ???, XXXX, DOI:10.1029/, Molar Mass, Surface Tension, and Droplet Growth Kinetics of  

E-print Network

GEOPHYSICAL RESEARCH LETTERS, VOL. ???, XXXX, DOI:10.1029/, Molar Mass, Surface Tension are 4370±24% and 4340±18% kg kmol-1 . KTA is used to infer surface tension depression, and is in excellent organic carbon [Asa-Awuku et al., in re- view]. Asa-Awuku et al. [in review] first extended KTA to 1School

Nenes, Athanasios

273

Mineral Specific IR Molar Absorption Coefficients for Routine Water Determination in Olivine, SiO2 polymorphs and Garnet  

Microsoft Academic Search

Conventionally applied Infrared (IR) calibrations [1, 2] for quantitative water analyses in solids are established on hydrous minerals and glasses with several wt% water. These calibrations are based on a negative correlation between the IR molar absorption coefficient (?) for water and the mean wavenumber of the corresponding OH pattern. The correlation reflects the dependence of the OH band position

S. Thomas; M. Koch-Mueller; P. Reichart; D. Rhede; R. Thomas

2007-01-01

274

Poly(ethylene oxide)\\/Laponite nanocomposites via melt-compounding: effect of clay modification and matrix molar mass  

Microsoft Academic Search

The present study focuses on the preparation of poly(ethylene oxide) (PEO) nanocomposites based on the synthetic Laponite clay. The clay was added both in its pure form as well as organically modified with low molar mass poly(ethylene glycol) (PEG) components in order to enhance the compatibility between Laponite and PEO. Several PEG's with different end groups were used. Almost all

Wendy Loyens; Patric Jannasch; Frans H. J. Maurer

2005-01-01

275

Excess Molar Volumes and Thermal Expansivities of Aqueous Solutions of Dimethylsulfoxide, Tetrahydrofuran and 1,4Dioxane  

Microsoft Academic Search

Densities, ? , of the systems water (W) + dimethylsulfoxide (DMSO), W + tetrahydrofuran (THF) and W + 1,4-dioxane (DO) have been determined in the temperature range 303.15-323.15 K. Excess molar volumes, $V_m^E $ , have been found to be negative and large in magnitude. Thermal expansivities, f , and excess thermal expansivities, f E , have been calculated. Densities,

Muhammad A. Saleh; Shamim Akhtar; M. Shamsuddin Ahmed; Mohammad Hemayet Uddin

2002-01-01

276

Use of palatal miniscrew anchorage and lingual multi-bracket appliances to enhance efficiency of molar scissors-bite correction.  

PubMed

This article reports the successful treatment method of scissors-bite correction using miniscrew anchorage and a lingual multi-bracket appliance. A female patient, 17 years and 4 months old, had a chief complaint of crowding of anterior teeth. The patient was given the diagnosis of Angle Class I malocclusion with bimaxillary protrusion and incisor crowding. She also showed a scissors-bite of the second molar on the right side. Miniscrews were inserted into the palatal region of the upper second molar to reinforce the anchorage, and a lingual multi-bracket appliance was placed into the maxilla. Miniscrews inserted palatally were used to correct the scissors-bite in the first 3 months; afterward, they were used to retract the six anterior teeth. The total active treatment period was 26 months. Because of the bite-plane effect, the upper and lower molars were separated in occlusion, and the scissors-bite was corrected effectively within a short time. The combined use of palatal miniscrew anchorage and lingual multi-bracket appliances enhances efficiency of molar scissors-bite correction. PMID:19413381

Tamamura, Nagato; Kuroda, Shingo; Sugawara, Yasuyo; Takano-Yamamoto, Teruko; Yamashiro, Takashi

2009-05-01

277

Excess molar volumes of mixtures of hexane + natural oils from 298.15 to 313.15 K  

SciTech Connect

Excess molar volume data for mixtures containing hexane with three edible oils: olive, corn, and pip of grape have been determined from density measurements at various temperatures between 298.15 and 313.15 K using a vibrating tube densimeter. Results have been correlated by the Redlich-Kister equation. Systems showed negative deviations from ideality in the whole composition range.

Gonzalez, C.; Resa, J.M.; Ruiz, A.; Gutierrez, J.I. [Univ. del Pais Vasco, Vitoria (Spain). Dept. of Chemical Engineering] [Univ. del Pais Vasco, Vitoria (Spain). Dept. of Chemical Engineering

1997-03-01

278

Name: Ghanem Question: In patients undergoing third molar surgery, will use of diclofenac sodium, as compared to  

E-print Network

, as compared to ibuprofen, result in better control of postoperative pain? PICO: (patient, intervention, comparison, outcome) P: 18 y/o, third molar surgery I: Use of diclofenac sodium C: ibuprofen O: Control the pain after the surgery Question Type: treatment Search Strategy: Diclofenac sodium AND ibuprofen

Goldman, Steven A.

279

Comparison of the Cleaning Efficacy of Passive Sonic Activation and Passive Ultrasonic Activation After Hand Instrumentation in Molar Root Canals  

Microsoft Academic Search

The purpose of this study was to compare the cleaning efficacy of passive ultrasonic activation with that of passive sonic activation after hand instrumentation. Sixty curved molar canals were hand-instrumented to size 35 and divided into three groups. Group 1 received no further treat- ment. Group 2 received 3 rain of passive sonic activation. Group 3 received 3 rain of

Scott A. Jensen; Thomas L. Walker; Jeffrey W. Hutter; Brian K. Nicoll

280

Prevalência de Perda Precoce de Molares De cíduos em Crianças Atendidas na Faculdade de Odontologia da Universidade de Pernambuco  

Microsoft Academic Search

Key-words Foi realizado um estudo transversal com objetivo de determinar a prevalência de perda precoce de molares decíduos e sua relação com o sexo, a faixa etária e o arco dentário. A amostra foi constituída dos prontuários de 1056 crianças de ambos os sexos, na faixa etária de 3 a 9 anos, atendidas na Faculdade de Odontologia da Universidade de

Natalie Kelner; Maria José Rodrigues; Karla Soares de Miranda

2003-01-01

281

Efficacy of platelet-rich plasma applied to post-extraction retained lower third molar alveoli. A systematic review  

PubMed Central

Dental retentions have a high prevalence among the general population and their removal can involve multiple complications. The use of platelet rich plasma has been proposed in an attempt to avoid these complications, as it contains high growth factors and stimulates diverse biological functions that facilitate the healing of soft and hard tissues. Objectives: To evaluate the available scientific evidence related to the application of platelet-rich plasma in the post-extraction alveoli of a retained lower third molars. Material and Methods: A systematic review of published literature registered in the Medline, EMBASE, Cochrane and NIH databases. The following categories were included: human randomized clinical studies. Key search words were: platelet rich plasma; platelet rich plasma and oral surgery; platelet rich in growth factors and third molar. Results: Of 101 potentially valid articles, seven were selected, of which four were rejected as they failed to meet quality criteria. Three studies fulfilled all selection and quality criteria: Ogundipe et al.; Rutkowski et al.; Haraji et al. The studies all measured osteoblast activity by means of sintigraphy, and also registered pain, bleeding, inflammation, temperature, numbness as perceived by the patients, radiological bone density and the incidence of alveolar osteitis. Conclusions: Scientific evidence for the use of PRP in retained third molar surgery is poor. For this reason randomized clinical trials are needed before recommendations for the clinical application of PRP can be made. Key words:Platelet rich plasma, lower third molar surgery, postoperative. PMID:24316707

Barona-Dorado, Cristina; Gonzalez-Regueiro, Iria; Martin-Ares, Maria; Arias-Irimia, Oscar; Martinez-Gonzalez, Jose M.

2014-01-01

282

Comparison of dental measurement systems for taxonomic assignment of Neanderthal and modern human lower second deciduous molars  

Microsoft Academic Search

Traditional morphometric approaches for taxonomic assignment of Neanderthal and modern human dental remains are mainly characterized by caliper measurements of tooth crowns. Several studies have recently described differences in dental tissue proportions and enamel thickness between Neanderthal and modern human teeth. At least for the lower second deciduous molar (dm2), a three-dimensional lateral relative enamel thickness index has been proposed

Stefano Benazzi; Cinzia Fornai; Priscilla Bayle; Michael Coquerelle; Ottmar Kullmer; Francesco Mallegni; Gerhard W. Weber

2011-01-01

283

Effect of Food Size on the Movement of the Mandibular First Molars and Condyles during Deliberate Unilateral Mastication in Humans  

Microsoft Academic Search

To date, the effect of food size on the movement of the mandibular first molars and condyles during chewing has not been fully examined due to methodological problems. The purpose of the present study was to examine the previously unknown effect of food size on masticatory jaw movement. Using a face bow, light-emitting diodes, and optical cameras, we recorded, in

S. Miyawaki; N. Ohkochi; T. Kawakami; M. Sugimura

2000-01-01

284

Comparison of the efficacy of two anesthetic techniques of mandibular primary first molar: A randomized clinical trial  

PubMed Central

Background: The most common technique to anesthetize mandibular primary teeth is inferior alveolar (I.A) nerve block injection which induces a relatively sustained anesthesia and in turn may potentially traumatize soft-tissues. Therefore, the need of having an alternative technique of anesthesia with a shorter term but the same efficacy is reasonable. The aim of this study was a comparison of the efficacy of two anesthetic techniques of mandibular primary first molar. Materials and Methods: In this randomized crossover clinical trial, 40 children with ages ranged from 5 years to 8 years whose mandibular primary first molars were eligible for pulpotomy, were selected and divided randomly into two groups. The right and left mandibular first molars of group A were anesthetized with infiltration and I. A nerve block techniques in the first and second sessions respectively. The left and right mandibular first molars of group B were anesthetized with I.A nerve block and infiltration techniques in the first and second sessions respectively. The severity of pain were measured and recorded according to sound-eye-motor scale by a certain person. Data was analyzed using Wilcoxon Signed Rank and Mann-Whitney U tests (P > 0.05). Results: The severity of pain was lower in infiltration technique versus I.A nerve block. There were no significant differences between the severities of pain on pulpal exposure of two techniques. Conclusion: It seems that infiltration technique is more favorable to anesthetize the mandibular primary first molar compared to I.A nerve block. PMID:24348619

Tudeshchoie, Davood Ghasemi; Rozbahany, Neda Ahmadi; Hajiahmadi, Maryam; Jabarifar, Ebrahim

2013-01-01

285

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. PMID:23337203

Lai, Jui-Yang

2013-01-01

286

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

287

A clinical trial of pulpotomy vs. root canal therapy of mature molars.  

PubMed

Root canal therapy (RCT) and tooth extraction are the main treatment options for irreversible pulpitis or its sequelae. Pulpotomy is an alternative treatment; however, more evidence is required. If outcomes of pulpotomy with a calcium-enriched mixture (PCEM) are non-inferior for mature molars with irreversible pulpitis compared with those from one-visit RCT (ORCT), this may be a beneficial treatment option. Four hundred seven individuals met the inclusion criteria and were randomly allocated [PCEM (n = 205), ORCT (n = 202)]. We used NRS questionnaires to record pain intensity. Six-month clinical and radiographic successes were assessed. Individuals in the ORCT arm reported significantly more post-operative pain than those in the PCEM arm (P < 0.001). Clinical success rates in the two arms showed no statistically significant difference; however, the radiographic success rates were significantly greater in the PCEM arm (P < 0.001). This trial suggests PCEM as an alternative for treatment of irreversible pulpitis. If long-term results confirm initial ones, PCEM may revolutionize oral health worldwide. PMID:20562409

Asgary, S; Eghbal, M J

2010-10-01

288

Probabilistic classification of age by third molar development: the use of soft evidence.  

PubMed

This study introduces a method to classify individuals according to an age threshold, given sex and third molars' dental maturity measured on the Demirjian scale by expressing uncertainty on dental evidence (soft evidence). We introduced a procedure to learn the parameters of the Naïve Bayes model, and we discussed two classification rules. The model was estimated and tested on 559 Italians aged 16-22. Two experts provided the dental evaluations, and the model was estimated for each of them. We evaluated the coherence of the evidence provided by the experts. Some indexes have been proposed to evaluate the effectiveness of the models, emphasizing how the experts' ability and the technology affect the results. We introduced two benchmarks, one based on the sample distribution per sex and age: in this case, probability of correct classification increases 22% and the proportion of false adults impressively decreases 80.2%; the other benchmark, obtained by simulating hard evidence, shows how the use of soft evidence increases the proportion of correct classification 3.1% and decreases the crucial proportion of false adults about 20%. Similarly, the proportion of false minors decreases about 5.3%. PMID:22803954

Corradi, Fabio; Pinchi, Vilma; Barsanti, Iljà; Garatti, Stefano

2013-01-01

289

Introductory Chemistry: A Molar Relaxivity Experiment in the High School Classroom  

PubMed Central

Dotarem and Magnevist, two clinically available magnetic resonance imaging (MRI) contrast agents, were assessed in a high school science classroom with respect to which is the better contrast agent. Magnevist, the more efficacious contrast agent, has negative side effects because its gadolinium center can escape from its ligand. However, Dotarem, though a less efficacious contrast agent, is a safer drug choice. After the experiment, students are confronted with the FDA warning on Magnevist, which enabled a discussion of drug efficacy versus safety. We describe a laboratory experiment in which NMR spin lattice relaxation rate measurements are used to quantify the relaxivities of the active ingredients of Dotarem and Magnevist. The spin lattice relaxation rate gives the average amount of time it takes the excited nucleus to relax back to the original state. Students learn by constructing molar relaxivity curves based on inversion recovery data sets that Magnevist is more relaxive than Dotarem. This experiment is suitable for any analytical chemistry laboratory with access to NMR. PMID:23929983

Dawsey, Anna C.; Hathaway, Kathryn L.; Kim, Susie; Williams, Travis J.

2013-01-01

290

Distal movement of premolars to provide posterior abutments for missing molars.  

PubMed

In 24 patients with missing molar teeth in the upper and/or in the lower jaw, 32 premolars were distalized. The mean orthodontic distalizing distance was 9.4 mm (SD 2.6). After distalization all these teeth served as posterior abutments for fixed restorations. The investigation period ranged between 2.5 to 14.1 years, average 9.6 years (SD 3.2). The clinical examination criteria were sensitivity, mobility, probing depth, sulcus bleeding index; the radiologic criteria were root resorption (lateral and apical) marginal bone level and axial position. None of the 32 premolar abutments were lost during investigation period. All the teeth maintained their vitality. The measured probing depths and sulcus bleeding indices were low. Of the teeth tested 40.6% revealed localized lateral root resorption on the pressure side; the average postorthodontic depth of root resorption was 0.7 mm (SD 0.3), and the length 2.3 mm (SD 0.6). The follow-up examination revealed a partial repair of the lateral root lesions. The extent of apical root resorption amounted to 0.9 mm (SD 1.1). The marginal bone level showed a bone loss of 0.5 mm mesially and 0.2 mm distally. The findings confirm that the distalized premolar functioning as a posterior bridge abutment represents a prognostically favorable alternative to an implant. PMID:8638576

Diedrich, P R; Fuhrmann, R A; Wehrbein, H; Erpenstein, H

1996-04-01

291

Isolation of pluripotent stem cells from human third molar dental pulp.  

PubMed

Potent stem/progenitor cells have been isolated from normal human dental pulps, termed dental pulp stem cells (DPSCs). However, no study has described the presence of stem cell populations in human dental pulp from the third molar with embryonic phenotypes. The dental pulp tissue was cultured in media with the presence of LIF, EGF, and PDGF. In the present study, we describe a new population of pluripotent stem cells that were isolated from dental pulp (DPPSC). These cells are SSEA-4(+), Oct4(+), Nanog(+), FLK-1(+), HNF3beta(+), Nestin(+), Sox2(+), Lin28(+), c-Myc(+), CD13(+), CD105(+), CD3(-), CD45(-), CD90(low), CD29(+), CD73(low), STRO-1(low) and CD146(-). We have investigated by SEM analysis and q-RT-PCR the capacity of DPPSCs to 3D differentiate in vitro using the Cell Carrier 3D glass scaffold into tissues that have similar characteristics to embryonic mesoderm and endoderm layers. These data would support the use of these cells, which are derived from an easily accessible source and can be used in future regeneration protocols for many tissue types that differentiate from the three embryonic layers. PMID:21692038

Atari, M; Barajas, M; Hernández-Alfaro, F; Gil, C; Fabregat, M; Ferrés Padró, E; Giner, L; Casals, N

2011-08-01

292

Effect of single dose preoperative intramuscular dexamethasone injection on lower impacted third molar surgery.  

PubMed

This study aimed to investigate the effects of dexamethasone intramuscular injection 1h preoperatively, in reducing facial swelling, pain and trismus after lower impacted third molar (LITM) surgery. Twenty healthy Thai patients with both LITM surgical extraction were enrolled in the study. The washout period was 1 month after the first operation. Clinical assessment of the facial swelling, pain and trismus were measured before and after operation for 7 days and the patient's total analgesic consumption was recorded. The level of significance used in the statistical decisions was P<0.05. Preoperative intramuscular injection of single-dose 8mg dexamethasone reduced postoperative swelling after LITM surgical extraction significantly on the second postoperative day, but immediately after surgery and on day 7 after the surgical extraction, no significant difference was found between the dexamethasone and control groups. Dexamethasone also reduced postoperative pain after LITM surgical extraction significantly on postoperative days 2 and 7. Additionally, the amount of paracetamol decreased significantly. There were no significant differences in trismus in the study and control groups 7 days after LITM operation. Single-dose intramuscular injection of dexamethasone can reduce postoperative facial swelling and pain, without affecting trismus after LITM surgical extraction. PMID:22209181

Klongnoi, Boworn; Kaewpradub, Pariya; Boonsiriseth, Kiatanant; Wongsirichat, Natthamet

2012-03-01

293

BrO/SO2 molar ratios from scanning DOAS measurements in the NOVAC network  

NASA Astrophysics Data System (ADS)

The molar ratio of BrO to SO2 is, like other halogen/sulfur ratios, a possible precursor for dynamic changes in the shallow part of a volcanic system. While the predictive significance of the BrO/SO2 ratio has not been well constrained yet, it has the major advantage that this ratio can be readily measured using the remote-sensing technique differential optical absorption spectroscopy (DOAS) in the UV. While BrO/SO2 ratios have been measured during several short-term field campaigns, this article presents an algorithm that can be used to obtain long-term time series of BrO/SO2 ratios from the scanning DOAS instruments of the Network for Observation of Volcanic and Atmospheric Change (NOVAC) or comparable networks. Parameters of the DOAS retrieval of both trace gases are given. The influence of co-adding spectra on the retrieval error and influences of radiative transfer will be investigated. Difficulties in the evaluation of spectroscopic data from monitoring instruments in volcanic environments and possible solutions are discussed. The new algorithm is demonstrated by evaluating data from the NOVAC scanning DOAS systems at Nevado del Ruiz, Colombia, encompassing almost 4 years of measurements between November 2009 and end of June 2013. This data set shows variations of the BrO/SO2 ratio several weeks prior to the eruption on 30 June 2012.

Lübcke, P.; Bobrowski, N.; Arellano, S.; Galle, B.; Garzón, G.; Vogel, L.; Platt, U.

2014-06-01

294

Effects of Nd:YAG laser pulpotomy on human primary molars.  

PubMed

The purpose of this study was to compare the effects of Nd:YAG laser pulpotomy to formocresol pulpotomy on human primary teeth. Patients with a primary tooth that required pulpotomy because of pulpal exposure to caries, were selected for this study. After removal of coronal pulpal tissue, Nd:YAG laser at 2 W, 20 Hz, 100 mJ or a 1:5 dilution of formocresol was introduced into the canal orifice for complete hemostasis. IRM paste was then placed over the pulp stump, and the tooth was restored either with composite resin or stainless steel crown. Sixty-eight teeth were treated with Nd:YAG laser and followed up for 6 to 64 months. Clinical success was achieved in 66 out of the 68 teeth (97 %), and 94.1 % were radiographically successful. In the control group, 69 primary molars were treated with formocresol and followed up for 9 to 66 months; 85.5 and 78.3% achieved clinical and radiographic success, respectively. The success rate of Nd:YAG laser pulpotomy was significantly higher than that of formocresol pulpotomy. The permanent successors of the laser-treated teeth erupted without any complications. PMID:16631836

Liu, Jeng-fen

2006-05-01

295

Indirect pulp therapy in a symptomatic mature molar using calcium enriched mixture cement.  

PubMed

Dental pulp has the ability of repair/regeneration. Indirect pulp therapy (IPT) is recommended for pulp preservation in asymptomatic teeth with extremely deep caries as well as teeth with clinical symptoms of reversible pulpitis. In this case study, we performed IPT with calcium enriched mixture (CEM) cement on a symptomatic permanent molar. After clinical/radiographic examinations the tooth was diagnosed with irreversible pulpitis and associated apical periodontitis. IPT involved partial caries removal, the placement of CEM cement pulp cap and overlying adhesive permanent restoration. At the 1 week follow-up, patient's spontaneous symptoms had resolved. One-year follow-up demonstrated pulp vitality, clinical function, as well as the absence of pain/tenderness to percussion/palpation/cold sensitivity tests; periapical radiograph showed a healing periradicular lesion with newly formed bone, that is normal pulp with normal periodontium. These favorable results indicate that IPT/CEM may be a good treatment option in comparison to endodontic treatment in young patients. IPT of deep-caries lesion is an easier, more practical and valuable treatment plan than complete caries removal. PMID:23349584

Torabzadeh, Hassan; Asgary, Saeed

2013-01-01

296

Endodontic retreatment of a mandibular first molar with five root canal systems: an important clinical lesson.  

PubMed

The objective of root canal treatment is to perform complete debridement of the root canals and subsequent obturation to facilitate healing of periapical pathosis. However, this process becomes complicated with the presence of additional root canal systems. The purpose of the present article is to report successful non-surgical retreatment of a mandibular first molar with five canals. This case report discusses the clinical management of a previously root filled mandibular firstmolar with two missed canal systems; distolingual and an additional mesial canal known as the middle mesial canal. The post-treatment radiographs show successful obturation to length in all canals. The middle mesial canal was found to be associated with mesiolingual canal and categorised as confluent. The configuration of canals in the mesial root was type XV, based on the classification given by Sert and Bayirli. This case report highlights the importance of knowledge and its application in the management of abnormal anatomic variants which play a crucial role in the success of endodontic retreatment. PMID:24654237

Hasan, Muhammad; Umer, Fahad

2014-01-01

297

Pressure distribution measurement in biting surimi gels with molars using a multiple-point sheet sensor.  

PubMed

The bite force of three surimi gels with molars was measured in the mouth using a multiple-point sheet sensor. A peak force appeared at the breaking point of each sample, and then the force increased again, accompanied by a decrease in the opening between the upper and lower teeth. Low values in the peak force, pressure, and time at the first peak, the time at which the maximum contact area was engaged, impulse, and slope of bite curve were observed in samples with low breaking force and low breaking deformation found by the mechanical measurement of gel strength, and with less toughness in the sensory assessment. The duration of the bite force, the second peak time, and active bite pressure at the second peak did not change with a change in the surimi texture. The active pressure at the breaking point of each gel was affected by gel strength, while that at the second peak was independent of the gel strength. PMID:11826953

Kohyama, K; Sakai, T; Azuma, T; Mizuguchi, T; Kimura, I

2001-12-01

298

Cervical and crown outline analysis of worn Neanderthal and modern human lower second deciduous molars.  

PubMed

Despite the general increase in digital techniques for dental morphometric analyses, only a few methods are available to study worn teeth. Moreover, permanent dentitions are studied much more frequently than deciduous teeth. In this study, we address both issues by providing a taxonomic classification of Neanderthal and modern human (MH) lower second deciduous molars (dm(2) s) through the analysis of crown and cervical outlines. Crown and cervical outlines were obtained from a three-dimensional (3D) digital sample of uniformly oriented dm(2) s. Both outlines were centered on the centroid of their area and represented by 16 pseudolandmarks obtained by equiangularly spaced radial vectors out of the centroid. We removed size information from the oriented and centered outlines with a uniform scaling of the pseudolandmark configurations to unit Centroid Size. Group shape variation was evaluated separately for the dm(2) crown and cervical outlines through a shape-space principal component (PC) analysis. Finally, quadratic discriminant analysis of a subset of PCs was used to classify the specimens. Our results demonstrate that both outlines successfully separate the two groups. Neanderthals showed a buccodistal expansion and convex lingual outline shape, whilst MHs have buccodistal reduction and straight lingual outline shape. Therefore, we confirmed that the cervical outline represents an effective parameter for distinguishing between the two taxa when dealing with worn or damaged dm(2) s. PMID:23077004

Benazzi, Stefano; Fornai, Cinzia; Buti, Laura; Toussaint, Michel; Mallegni, Francesco; Ricci, Stefano; Gruppioni, Giorgio; Weber, Gerhard W; Condemi, Silvana; Ronchitelli, Annamaria

2012-12-01

299

Ecogeographic variation in Neandertal dietary habits: evidence from occlusal molar microwear texture analysis.  

PubMed

In the late Middle and early Late Pleistocene, Neandertals inhabited a wide variety of ecological zones across western Eurasia during both glacial and interglacial times. To elucidate the still poorly understood effects of climatic change on Neandertal subsistence patterns, this study employs dental microwear texture analysis to reconstruct the diets of Neandertal individuals from various sites across their wide temporal and geographic ranges. The results of this study reveal environmentally-driven differences in the diets of Neandertal groups. Significant differences in microwear signatures, correlated with paleoecological conditions, were found among Neandertal groups that lived in open, mixed, and wooded environments. In comparison to recent hunter-gatherer populations with known, yet diverse diets, the occlusal molar microwear signatures of all the Neandertal groups indicate that their diet consisted predominantly of meat. However, the results of this study suggest that plant foods did form an important part of the diet of at least some Neandertal groups (i.e., those that lived in mixed and wooded habitats). Overall, the proportion of plant foods in the Neandertal diet appears to have increased with the increase in tree cover. PMID:21719068

El Zaatari, Sireen; Grine, Frederick E; Ungar, Peter S; Hublin, Jean-Jacques

2011-10-01

300

Relationship between cusp size and occlusal wear pattern in Neanderthal and Homo sapiens first maxillary molars.  

PubMed

Tooth wear studies in mammals have highlighted the relationship between wear facets (attritional areas produced during occlusion by the contact between opposing teeth) and physical properties of the ingested food. However, little is known about the influence of tooth morphology on the formation of occlusal wear facets. We analyzed the occlusal wear patterns of first maxillary molars (M(1) s) in Neanderthals, early Homo sapiens, and contemporary modern humans. We applied a virtual method to analyze wear facets on the crown surface of three-dimensional digital models. Absolute and relative wear facet areas are compared with cusp area and cusp height. Although the development of wear facets partially follows the cusp pattern, the results obtained from the between-group comparisons do not reflect the cusp size differences characterizing these groups. In particular, the wear facets developed along the slopes of the most discriminate cusp between Neanderthals and Homo sapiens (hypocone) do not display any significant difference. Moreover, no correlations have been found between cusp size and wear facet areas (with the exception of the modern sample) and between cusp height and wear facet areas. Our results suggest that cusp size is only weakly related to the formation of the occlusal wear facets. Other factors, such as, diet, food processing, environmental abrasiveness, and nondietary habits are probably more important for the development and enlargement of wear facets, corroborating the hypotheses suggested from previous dental wear studies. PMID:21337711

Fiorenza, Luca; Benazzi, Stefano; Viola, Bence; Kullmer, Ottmar; Schrenk, Friedemann

2011-03-01

301

BrO/SO2 molar ratios from scanning DOAS measurements in the NOVAC network  

NASA Astrophysics Data System (ADS)

The molar ratio of BrO to SO2 is, like other halogen/sulphur ratios, a~possible precursor for dynamic changes in the shallow part of a volcanic system. While the predictive significance of the BrO/SO2 ratio has not been well constrained yet, it has the major advantage that this ratio can be readily measured using the remote-sensing technique Differential Optical Absorption Spectroscopy (DOAS) in the UV. While BrO/SO2 ratios have been measured during several short-term field campaigns this article presents an algorithm that can be used to obtain long-term time series of BrO/SO2 ratios from the scanning DOAS instruments of the Network for Observation of Volcanic and Atmospheric Change (NOVAC) or comparable networks. Parameters of the DOAS retrieval of both trace gases are given and the influence of co-adding spectra on the retrieval error will be investigated. Difficulties in the evaluation of spectroscopic data from monitoring instruments in volcanic environments and possible solutions are discussed. The new algorithm is demonstrated by evaluating data from the NOVAC scanning DOAS systems at Nevado del Ruiz, Colombia encompassing almost four years of measurements between November 2009 and end of June 2013. This dataset shows variations of the BrO/SO2 ratio several weeks prior to the eruption on 30 June 2012.

Lübcke, P.; Bobrowski, N.; Arellano, S.; Galle, B.; Garzón, G.; Vogel, L.; Platt, U.

2013-11-01

302

Endodontic treatment of mandibular molar with root dilaceration using Reciproc single-file system  

PubMed Central

Biomechanical preparation of root canals with accentuated curvature is challenging. New rotatory systems, such as Reciproc, require a shorter period of time to prepare curved canals, and became a viable alternative for endodontic treatment of teeth with root dilaceration. Thus, this study aimed to report a clinical case of endodontic therapy of root with accentuated dilaceration using Reciproc single-file system. Mandibular right second molar was diagnosed as asymptomatic irreversible pulpitis. Pulp chamber access was performed, and glide path was created with #10 K-file (Dentsply Maillefer) and PathFile #13, #16 and #19 (Dentsply Maillefer) up to the temporary working length. The working length measured corresponded to 20 mm in the mesio-buccal and mesio-lingual canals, and 22 mm in the distal canal. The R25 file (VDW GmbH) was used in all the canals for instrumentation and final preparation, followed by filling with Reciproc gutta-percha cones (VDW GmbH) and AH Plus sealer (Dentsply Maillefer), using thermal compaction technique. The case has been receiving follow-up for 6 mon and no painful symptomatology or periapical lesions have been found. Despite the difficulties, the treatment could be performed in a shorter period of time than the conventional methods. PMID:24010084

Meireles, Daniely Amorin; Bastos, Mariana Mena Barreto; Marques, Andre Augusto Franco; Sponchiado, Emilio Carlos

2013-01-01

303

Genes Expressed in Dental Enamel Development Are Associated with Molar-Incisor Hypomineralization  

PubMed Central

Genetic disturbances during dental development influence variation of number and shape of the dentition. In this study, we tested if genetic variation in enamel formation genes is associated with molar-incisor hypomineralization (MIH), also taking into consideration caries experience. DNA samples from 163 cases with MIH and 82 unaffected controls from Turkey, and 71 cases with MIH and 89 unaffected controls from Brazil were studied. Eleven markers in five genes [ameloblastin (AMBN), amelogenin (AMELX), enamelin (ENAM), tuftelin (TUFT1), and tuftelin-interacting protein 11 (TFIP11)] were genotyped by the TaqMan method. Chi-square was used to compare allele and genotype frequencies between cases with MIH and controls. In the Brazilian data, distinct caries experience within the MIH group was also tested for association with genetic variation in enamel formation genes. The ENAM rs3796704 marker was associated with MIH in both populations (Brazil: p=0.03; OR=0.28; 95% C.I.=0.06–1.0; Turkey: p=1.22e–012; OR=17.36; 95% C.I.=5.98–56.78). Associations between TFIP11 (p=0.02), ENAM (p=0.00001), and AMELX (p=0.01) could be seen with caries independent of having MIH or genomic DNA copies of Streptococcus mutans detected by real time PCR in the Brazilian sample. Several genes involved in enamel formation appear to contribute to MIH. PMID:23790503

Jeremias, Fabiano; Koruyucu, Mine; Kuchler, Erika C.; Bayram, Merve; Tuna, Elif B.; Deeley, Kathleen; Pierri, Ricardo A.; Souza, Juliana F.; Fragelli, Camila M.B.; Paschoal, Marco A.B.; Gencay, Koray; Seymen, Figen; Caminaga, Raquel M.S.; dos Santos-Pinto, Lourdes; Vieira, Alexandre R.

2013-01-01

304

Genes expressed in dental enamel development are associated with molar-incisor hypomineralization.  

PubMed

Genetic disturbances during dental development influence variation of number and shape of the dentition. In this study, we tested if genetic variation in enamel formation genes is associated with molar-incisor hypomineralization (MIH), also taking into consideration caries experience. DNA samples from 163 cases with MIH and 82 unaffected controls from Turkey, and 71 cases with MIH and 89 unaffected controls from Brazil were studied. Eleven markers in five genes [ameloblastin (AMBN), amelogenin (AMELX), enamelin (ENAM), tuftelin (TUFT1), and tuftelin-interacting protein 11 (TFIP11)] were genotyped by the TaqMan method. Chi-square was used to compare allele and genotype frequencies between cases with MIH and controls. In the Brazilian data, distinct caries experience within the MIH group was also tested for association with genetic variation in enamel formation genes. The ENAM rs3796704 marker was associated with MIH in both populations (Brazil: p=0.03; OR=0.28; 95% C.I.=0.06-1.0; Turkey: p=1.22e-012; OR=17.36; 95% C.I.=5.98-56.78). Associations between TFIP11 (p=0.02), ENAM (p=0.00001), and AMELX (p=0.01) could be seen with caries independent of having MIH or genomic DNA copies of Streptococcus mutans detected by real time PCR in the Brazilian sample. Several genes involved in enamel formation appear to contribute to MIH. PMID:23790503

Jeremias, Fabiano; Koruyucu, Mine; Küchler, Erika C; Bayram, Merve; Tuna, Elif B; Deeley, Kathleen; Pierri, Ricardo A; Souza, Juliana F; Fragelli, Camila M B; Paschoal, Marco A B; Gencay, Koray; Seymen, Figen; Caminaga, Raquel M S; dos Santos-Pinto, Lourdes; Vieira, Alexandre R

2013-10-01

305

Isolation and characterization of stem cells derived from human third molar tooth germs of young adults: implications in neo-vascularization, osteo-, adipo- and neurogenesis  

Microsoft Academic Search

A number of studies have reported in the last decade that human tooth germs contain multipotent cells that give rise to dental and peri-odontal structures. The dental pulp, third molars in particular, have been shown to be a significant stem cell source. In this study, we isolated and characterized human tooth germ stem cells (hTGSCs) from third molars and assessed

M E Yalvac; M Ramazanoglu; A A Rizvanov; F Sahin; O F Bayrak; U Salli; A Palotás; G T Kose

2010-01-01

306

Determining the molar mass of a plasma substitute succinylated gelatin by size exclusion chromatography–multi-angle laser light scattering, sedimentation equilibrium and conventional size exclusion chromatography  

Microsoft Academic Search

The clinical effectiveness of succinylated gelatin as a plasma substitute depends strongly on its molar mass, determined conventionally by size exclusion chromatography (SEC). This study evaluates different SEC calibration standards in comparison with two independent “absolute” methods for determining the weight average molar mass (Mw) of a succinylated gelatin sample. SEC calibrated using succinylated gelatin fractions correlated well with size

Manjit Kaur; Kornelia Jumel; Kim R. Hardie; Andrea Hardman; John Meadows; Colin D. Melia

2002-01-01

307

Evaluating controlling factors to Al(i)/(Ca + Mg) molar ratio in acidic soil water, southern and southwestern China: multivariate approach.  

PubMed

Al(i)/(Ca + Mg) molar ratio in soil water has been used as an indicator to the effects of acid deposition on terrestrial ecosystems. However, the main factors controlling this ratio have not been well documented in southern and southwestern China. In this study, we presented the variation in inorganic aluminum (Al(i)) and Al(i)/(Ca + Mg) molar ratio in different sites and soil horizons based on two to three years monitoring data, and evaluated the main factors controlling Al(i)/(Ca + Mg) molar ratio using principle component analysis (PCA) and partial least square (PLS) regression. Monitoring data showed although Al(i)/(Ca + Mg) molar ratios in most soil water were lower than assumed critical 1.0, higher molar ratios were found in some soil water at TSP and LXH site. Besides acid loading, both soil properties and soil water chemistry affected the value of Al(i)/(Ca + Mg) molar ratio in soil water. Partial least square (PLS) indicated that they had different relative importance in different soil horizons. In A-horizon, soil aluminum saturation (AlS) had higher influence on Al(i)/(Ca + Mg) molar ratio than soil water chemistry did; higher soil aluminum saturation (AlS) led to higher Al(i)/(Ca + Mg) molar ratio in soil water. In the deeper horizons (i.e., B(1)-, B(2)- and BC-horizon), inorganic aluminum (Al(i)) in soil water had more and more important role in regulating Al(i)/(Ca + Mg) molar ratio. On regional scale, soil aluminum saturation (AlS) as well as cation exchange capacity (CEC) was the dominant factor controlling Al(i)/(Ca + Mg) molar ratio. This should be paid enough attention on when making regional acid rain control policy in China. PMID:17057971

Guo, Jing-Heng; Zhang, Xiao-Shan; Vogt, Rolf D; Xiao, Jin-Song; Zhao, Da-Wei; Xiang, Ren-Jun; Luo, Jia-Hai

2007-06-01

308

Molar mass profiling of synthetic polymers by free-solution capillary electrophoresis of DNA-polymer conjugates.  

PubMed

The molar mass distribution of a polymer sample is a critical determinant of its material properties and is generally analyzed by gel permeation chromatography or more recently, by MALDI-TOF mass spectrometry. We describe here a novel method for the determination of the degree of polymerization of polydisperse, uncharged, water-soluble polymers (e.g., poly(ethylene glycol) (PEG)), based upon single-monomer resolution of DNA-polymer conjugates by free-solution capillary electrophoresis. This is accomplished by end-on covalent conjugation of a polydisperse, uncharged polymer sample (PEG) to a monodisperse, fluorescently labeled DNA oligomer, followed by electrophoretic analysis. The monodisperse, charged DNA "engine" confers to each conjugate an equal amount of electromotive force, while the varying contour lengths of the uncharged, polydisperse polymers engender different amounts of hydrodynamic drag. The balance of electromotive and hydrodynamic forces enables rapid, high-resolution separation of the DNA-polymer conjugates as a function of the size of the uncharged PEG tail. This provides a profile of the molar mass distribution of the original polymer sample that can be detected by laser-induced fluorescence through excitation of the dye-labeled DNA. We call this method free solution conjugate electrophoresis (FSCE). Theory-based analysis of the resulting electrophoresis data allows precise calculation of the degree of polymerization of the PEG portion of each conjugate molecule. Knowledge of the molecular mass of the uncharged polymer's repeat unit allows for direct calculation of the molar mass averages as well as sample polydispersity index. The results of these analyses are strikingly reminiscent of MALDI-TOF spectra taken of the same PEG samples. PEG samples of 3.4-, 5-, and 20-kDa nominal average molar mass were analyzed by FSCE and MALDI-TOF; the values of the molar mass averages, Mw and Mn, typically agree to within 5%. Measurements and molar mass calculations are performed without any internal standards or calibration. Moreover, when DNA-polymer conjugate analysis is performed in a chip-based electrophoresis system, separation is complete in less than 13 min. FSCE offers an alternative to MALDI-TOF for the characterization of uncharged, water-soluble polymers that can be uniquely conjugated to DNA. PMID:11338593

Vreeland, W N; Desruisseaux, C; Karger, A E; Drouin, G; Slater, G W; Barron, A E

2001-04-15

309

Developmental variations in plasma leptin, leptin soluble receptor and their molar ratio in healthy infants  

PubMed Central

Background Leptin and its soluble receptor (sOB-R) are important to regulation of body composition but there are no data on the developmental variations in these plasma variables and their relationship with body composition measurements, Methods Weight, length, and body composition (bone, fat and lean mass) by dual energy absorptiometry, and plasma variables were measured in healthy infants at 2, 4, 8 and 12 months. Results 15 whites and 29 African Americans (21 males and 23 females) with mean birth weight 3357 +/- 45 (SEM) g and gestation of 39.3 +/- 0.17 weeks were studied. The overall Z score for weight, length and weight for length during the study were 0.00 +/- 0.15, -0.08 +/- 0.11 and 0.12 +/- 0.14 respectively. With increasing age, plasma leptin (1.0 to 18.2, median 5.5 ng/mL) and sOB-R:leptin molar ratio (10.1 to 247.4, median 59.9) were lowered (r = -0.47, p < 0.01; and r = -0.37, p < 0.05 respectively), best predicted by weight Z score and percentage of fat mass, and higher in African American and female. Presence of body composition measurements eliminated the race and gender effect on the plasma variables. Plasma sOB-R (49.5 to 173.9, median 81.3 ng/mL) did not change significantly with age and was correlated and predicted only by body composition measurements. Conclusion In healthy growing infants, plasma leptin but not sOB-R decreases with age. Gender, race and anthropometric measurements are additional physiological determinants predictive of plasma leptin and the receptor:ligand ratio. However, body composition is the only variable that can predict plasma leptin and its soluble receptor and the receptor: ligand ratio; and body composition measurements eliminated the race and gender effect on these plasma variables. PMID:17547758

Koo, Winston WK; Hammami, Mouhanad; Hockman, Elaine M

2007-01-01

310

Relationship between hydroperoxide concentration and average molar mass in thermo-oxidized polyethylene  

NASA Astrophysics Data System (ADS)

The aim of this research project is to investigate the oxidation mechanism of high density polyethylene (HDPE) used in outdoor applications, in order to establish in a near future, a non-empirical kinetic model for lifetime prediction. The present paper focuses on the changes in the hydroperoxide (POOH) concentration induced by thermo-oxidative ageing, and on their relationship with the evolution of the weight average molar mass (Mw) due both to chain scission and crosslinking processes. Thin HDPE films were aged at 110 and 140°C in air under atmospheric pressure. In a first part, changes in the POOH concentration versus ageing time were assessed by three different analytical methods previously reported in the literature: modulated differential scattering calorimetry (MDSC), Fourier transform Infra-Red spectrometry after chemical derivatization treatment with gaseous sulfur dioxide (SO2-FTIR), and iodometry. A comparison of experimental results revealed that these three methods provide very similar quantitative data on POOH accumulation, whereas iodometry tends to strongly underestimate the subsequent stage of POOH decomposition. It was thus suspected that iodometry does not only titrate POOH, but also other chemical species (presumably double bonds) formed when POOH decompose. Therefore, only MDSC and SO2-FTIR were considered as relevant methods for POOH titration. In a second part, changes in Mw versus ageing time were monitored by size exclusion chromatography (SEC). A sharp drop of Mw was first observed at the beginning of exposure, which was assigned to an intensive chain scission process. Then, in a second stage, a stabilization or even a substantial re-increase in Mw was observed, suggesting a competition between chain scission and crosslinking processes. As this second stage starts at the same time as POOH decomposition, it was concluded that there is a strong correlation between both phenomena, occurring respectively at the macromolecular and molecular scales.

Da Cruz, Manuela; Van Schoors, Laetitia; Colin, Xavier; Benzarti, Karim

2014-05-01

311

Hertwig's epithelial root sheath cell behavior during initial acellular cementogenesis in rat molars.  

PubMed

This study was designed to examine developing acellular cementum in rat molars by immunohistochemistry, to elucidate (1) how Hertwig's epithelial root sheath disintegrates and (2) whether epithelial sheath cells transform into cementoblasts through epithelial-mesenchymal transition (EMT). Initial acellular cementogenesis was divided into three developmental stages, which can be seen in three different portions of the root: portion 1, where the epithelial sheath is intact; portion 2, where the epithelial sheath becomes fragmented; and portion 3, where acellular cementogenesis begins. Antibodies against three kinds of matrix proteinases, which degrade epithelial sheath-maintaining factors, including basement membrane and desmosomes, were used to investigate proteolytic activity of the epithelial sheath. Tissue non-specific alkaline phosphatase (TNALP) and keratin were used to investigate EMT. Epithelial sheath cells showed immunoreactivity for all three enzymes at fragmentation, which suggests that epithelial sheath disintegration is enzymatically mediated. Dental follicle cells and cementoblasts showed intense immunoreactivity for TNALP, and from portion 1 through to 3, the reaction extended from the alveolar bone-related zone to the root-related zone. Cells possessing keratin/TNALP double immunoreactivity were virtually absent. Keratin-positive epithelial sheath cells showed negligible immunoreactivity for TNALP, and epithelial cells did not appear to migrate to the dental follicle. Together, these findings suggest that a transition phenotype between epithelial cells and cementoblasts does not exist in the developing dental follicle and hence that epithelial sheath cells do not undergo EMT during initial acellular cementogenesis. In brief, this study supports the notion that cementoblasts derive from the dental follicle. PMID:24859538

Yamamoto, Tsuneyuki; Yamamoto, Tomomaya; Yamada, Tamaki; Hasegawa, Tomoka; Hongo, Hiromi; Oda, Kimimitsu; Amizuka, Norio

2014-11-01

312

Using occlusal wear information and finite element analysis to investigate stress distributions in human molars  

PubMed Central

Simulations based on finite element analysis (FEA) have attracted increasing interest in dentistry and dental anthropology for evaluating the stress and strain distribution in teeth under occlusal loading conditions. Nonetheless, FEA is usually applied without considering changes in contacts between antagonistic teeth during the occlusal power stroke. In this contribution we show how occlusal information can be used to investigate the stress distribution with 3D FEA in lower first molars (M1). The antagonistic crowns M1 and P2–M1 of two dried modern human skulls were scanned by ?CT in maximum intercuspation (centric occlusion) contact. A virtual analysis of the occlusal power stroke between M1 and P2–M1 was carried out in the Occlusal Fingerprint Analyser (OFA) software, and the occlusal trajectory path was recorded, while contact areas per time-step were visualized and quantified. Stress distribution of the M1 in selected occlusal stages were analyzed in strand7, considering occlusal information taken from OFA results for individual loading direction and loading area. Our FEA results show that the stress pattern changes considerably during the power stroke, suggesting that wear facets have a crucial influence on the distribution of stress on the whole tooth. Grooves and fissures on the occlusal surface are seen as critical locations, as tensile stresses are concentrated at these features. Properly accounting for the power stroke kinematics of occluding teeth results in quite different results (less tensile stresses in the crown) than usual loading scenarios based on parallel forces to the long axis of the tooth. This leads to the conclusion that functional studies considering kinematics of teeth are important to understand biomechanics and interpret morphological adaptation of teeth. PMID:21615398

Benazzi, Stefano; Kullmer, Ottmar; Grosse, Ian R; Weber, Gerhard W

2011-01-01

313

How to measure and predict the molar absorption coefficient of a protein.  

PubMed Central

The molar absorption coefficient, epsilon, of a protein is usually based on concentrations measured by dry weight, nitrogen, or amino acid analysis. The studies reported here suggest that the Edelhoch method is the best method for measuring epsilon for a protein. (This method is described by Gill and von Hippel [1989, Anal Biochem 182:319-326] and is based on data from Edelhoch [1967, Biochemistry 6:1948-1954]). The absorbance of a protein at 280 nm depends on the content of Trp, Tyr, and cystine (disulfide bonds). The average epsilon values for these chromophores in a sample of 18 well-characterized proteins have been estimated, and the epsilon values in water, propanol, 6 M guanidine hydrochloride (GdnHCl), and 8 M urea have been measured. For Trp, the average epsilon values for the proteins are less than the epsilon values measured in any of the solvents. For Tyr, the average epsilon values for the proteins are intermediate between those measured in 6 M GdnHCl and those measured in propanol. Based on a sample of 116 measured epsilon values for 80 proteins, the epsilon at 280 nm of a folded protein in water, epsilon (280), can best be predicted with this equation: epsilon (280) (M-1 cm-1) = (#Trp)(5,500) + (#Tyr)(1,490) + (#cystine)(125) These epsilon (280) values are quite reliable for proteins containing Trp residues, and less reliable for proteins that do not. However, the Edelhoch method is convenient and accurate, and the best approach is to measure rather than predict epsilon. PMID:8563639

Pace, C. N.; Vajdos, F.; Fee, L.; Grimsley, G.; Gray, T.

1995-01-01

314

[The structure of morphological variability (with the masticatory surface morphotypes of the lower first molar in voles as an example)].  

PubMed

An analysis of morphotypical variability of the lower first molar in twelve species of Microtus genus revealed similarity in patterns of variability, consisting in two-three homologous series of three morphotypes of one class of rugosity in each series. In the majority of species, morphotypes are located in a single plane. In some species, morphotypes of other class of rugosity form the homologous series of a second plane so that the structure of the variability takes on a three-dimensional form. The variability spectrum is limited by molars design; at the different trends in complication of a masticatory surface have taxonomic weight of subgenus or species rank. Thus, incompleteness of homologous series is caused by taxonomic specificity and is nonrandom in essence. PMID:21542335

Pozdniakov, A A

2011-01-01

315

Nonsurgical endodontic treatments in molar teeth with large periapical lesions in children: 2-year follow-up.  

PubMed

Profound caries lesions may lead to invasion of microorganisms to the dental pulp, and periapical areas can promote the development of dentoalveolar abscess and periapical bone loss. Treatment options to manage large periapical lesions range from nonsurgical root canal treatment and/or apical surgical procedure to extraction. Young molar teeth with pulp necrosis and large periapical lesions in children are frequently treated with root canal treatment because the therapy is more difficult in multirooted teeth. In these case reports, nonsurgical endodontic treatments performed on 6 molar teeth with large periapical lesions, by repeated intracanal dressing with calcium hydroxide, are presented. Radiographs displayed significant bony healing at the end of the second year. In conclusion, large periapical lesions can respond favorably to nonsurgical treatment, and complex and difficult endodontic treatments in children might not be required. PMID:17499527

Kusgoz, Adem; Yildirim, Sibel; Gokalp, Alparslan

2007-07-01

316

Dentigerous cyst associated with an ectopic third molar in the maxillary sinus: A case report and review of literature  

PubMed Central

Dentigerous cysts are the most common type of developmental odontogenic cysts arising from the crowns of impacted, embedded, or unerupted teeth. They constitute about 20% of all epithelium-lined cysts of the jaws. The teeth involved most often are mandibular third molar and maxillary canines. 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 fairly rare, and only 20 cases had been reported in Medline since 1980. In the present paper, we report an additional case of dentigerous cysts associated with ectopic third molar in the right maxillary sinus. Also, pathogenesis of ectopic tooth, role of advanced imaging, differential diagnosis, and management are discussed. PMID:23293505

Kasat, Vikrant O.; Karjodkar, Freny R.; Laddha, Ruchi S.

2012-01-01

317

Is post-operative antibiotic therapy justified for surgical removal of mandibular third molar? A comparative study.  

PubMed

Surgical removal of impacted mandibular third molar (SRIMTM) is the most common procedure performed in oral and maxillofacial surgery. In the literature, many complications associated with lower third molar removal are described such as pain, swelling, trismus, infection, inflammation, and nerve damage. Antibiotics are routinely used either pre-operatively or post-operatively to reduce the chances of surgical site infection (SSI). However routine use of antibiotics for SRIMTM is still controversial. For antibiotics to be effective in reducing post-operative infective complications, the time of administration is very important. Adequate serum concentration of antibiotic must be achieved prior to the procedure. In a developing country like India, antibiotics are routinely prescribed post-operatively. The current study is designed to evaluate the efficacy of post-operative prophylactic antibiotic in SRIMTM. PMID:24822012

Sane, Vikrant Dilip; Gadre, Kiran Shrikrishna; Chandan, Sanjay; Halli, Rajshekhar; Saddiwal, Rashmi; Kadam, Pankaj

2014-06-01

318

Characterization of Dental Pulp Stem Cells from Impacted Third Molars Cultured in Low Serum-Containing Medium  

Microsoft Academic Search

We isolated and expanded stem cells from dental pulp from extracted third molars using an innovative culture method consisting of low serum-containing medium supplemented with epidermal growth factor and platelet-derived growth factor BB. We evaluated the differentiation potential of these cells when they were growing either adherently or as micromass\\/spheroid cultures in various media. Undifferentiated and differentiated cells were analyzed

Jana Karbanová; Tomáš Soukup; Jakub Suchánek; Robert Pytlík; Denis Corbeil; Jaroslav Mokrý; W. Martens; R. Donders; E. Wolfs; J. Huang; J. Chen; R. Y. Shi

2011-01-01

319

Apparent Molar Volume, Heat Capacity, and Conductance of Lithium Bis (trifluoromethylsulfone)imide in Glymes and Other Aprotic Solvents  

Microsoft Academic Search

Lithium bis(trifluoromethylsulfone)imide (LiTFSI) is a promising electrolyte for high-energy lithium batteries due to its high solubility in most solvents and electrochemical stability. To characterize this electrolyte in solution, its conductance and apparent molar volume and heat capacity were measured over a wide range of concentration in glymes, tetraethylsulfamide (TESA), acetonitrile, ?-butyrolactone, and propylene carbonate at 25°C and were compared with

Dany Brouillette; Gérald Perron; Jacques E. Desnoyers

1998-01-01

320

Evaluation of isthmus prevalence, location, and types in mesial roots of mandibular molars in the Iranian Population  

PubMed Central

Background: Management of canal isthmus is considered as an important factor for successful endodontic treatment. Accordingly, this study was designed to determine the prevalence, location, and types of isthmus in mesial root canals of extracted mandibular molars in a sample of Iranian population. Materials and Methods: In this cross-sectional descriptive study, 60 extracted molars with two mesial canals were included. The samples were initially decoronated and then, roots were sectioned horizontally at 2, 4, and 6 mm levels from the apex via a low-speed handpiece with a thin metallic disk and finally prepared and stained with Indian ink. All sections were examined using a stereomicroscope at a magnification of ×30. Prevalence, location, and types of isthmus were evaluated based on the classifications by Kim and Teixeira and all data were statistically analyzed by the chi-squared test. The statistical significance level was established at 0.05. Results: Eighty-three percent of extracted mandibular molars had an isthmus at the mesial root. This prevalence increased with distance from the apex, that is, 92% at 6 mm from the apex and 70% at 2 mm from the apex. A statistically significant difference was found between the sections at 2 and 6 mm from the apex (P < 0.05), but no other significant differences between other levels (P > 0.05). Conclusion: Isthmus is very common in the mesial roots of the mandibular permanent molars in the Iranian population, with the highest prevalence in the 6 mm distance from the root apex. Therefore, detection, cleaning, and filling of these apical 6 mm isthmuses are of great benefit in modern endodontics. PMID:24932198

Mehrvarzfar, Payman; Akhlagi, Nahid Mohammadzade; Khodaei, Fatemeh; Shojaee, Golnaz; Shirazi, Sara

2014-01-01

321

Stimulatory effect of low-level laser therapy on root development of rat molars: a preliminary study  

Microsoft Academic Search

Several studies suggest a biomodulatory influence of low-level laser irradiation in the inflammatory and reparative processes\\u000a of dental tissues. The aim of this study was to investigate the stimulatory effect of 808-nm laser irradiation on root development\\u000a of rat molars and also to evaluate the histological reaction of pulp and periapical tissues. Twenty-four 30-day-old Wistar\\u000a male rats were randomly assigned

Lida Toomarian; Reza Fekrazad; Nikoo Tadayon; Jamileh Ramezani; Jan Tunér

322

Maxillary First Molars with Six Canals Diagnosed with the Aid of Cone Beam Computed Tomography: A Report of Two Cases  

PubMed Central

The case reports present the endodontic management of two maxillary first molars with six canals. The diagnosis of morphology of multiple canal systems was identified under magnification of the dental operating microscope and was confirmed with the help of cone beam computed tomography. This paper discusses the variations in the canal morphology and the use of the latest adjuncts in successfully diagnosing and treating unusual canal anatomy. PMID:23984111

Mehra, Neha

2013-01-01

323

Excess Chemical Potentials, Excess Partial Molar Enthalpies, Entropies, Volumes, and Isobaric Thermal Expansivities of Aqueous Glycerol at 25°C  

Microsoft Academic Search

The vapor pressures p the excess partial molar enthalpies of glycerol HGlyE the densities d and the thermal expansivities ap of aqueous glycerol were measured at 25°C. From the vapor pressure data, the excess chemical potential of H2O µWE was calculated, assuming that the partial pressure of glycerol pGly is negligibly small. The excess chemical potential of glycerol µ GlyE

Eric C. H. To; James V. Davies; Michael Tucker; Peter Westh; Christa Trandum; Kennth S. H. Suh; Yoshikata Koga

1999-01-01

324

Temperature determination in a transient free fuel jet with equilibrium temperature of the local molar mixture fraction  

Microsoft Academic Search

This paper presents the space-resolved temperature determination in the mixing zone of a transient free dimethyl ether jet\\u000a flowing into a non-moving atmosphere via the time-resolved local molar mixture fraction, obtained with tracer added Laser-induced\\u000a Fluorescence. The temperature of the mixture is calculated with an approach of an adiabatic mixing temperature. To validate\\u000a the obtained temperatures a high-speed thermocouple measures

Christian Pfeifer; Stephan Kress; Dietmar Kuhn

2010-01-01

325

A clinical and microbiological comparative study of deep carious lesion treatment in deciduous and young permanent molars.  

PubMed

The aim of this study was to compare one-visit indirect pulp treatment (IPT), two-visit IPT, and direct complete excavation (DCE) of deciduous and young permanent molars with deep carious lesions from clinical and microbiological points of view. One hundred thirty-five teeth (83 deciduous molars and 52 young permanent molars) were included in the study. The teeth were randomly selected and treated either with one-visit IPT, two-visit IPT, or DCE. For two-visit IPT, the final excavation was performed after a period of 3 months. The color, consistency, and humidity of the dentin at the cavity floor were recorded for clinical assessment, and dentin samples were obtained from all teeth. Dentin samples were microbiologically investigated for the total number of colony forming units, mutans streptococci, and lactobacilli. The results showed bacterial growth in 63.8% of the dentin samples in one-visit IPT, while in two-visit IPT, bacterial growth was observed in all of the samples (100%) after the first excavation. When the cavities were reopened before the final excavation, the number of samples with positive growth had decreased significantly (44.4%), and after the final excavation, the number of the samples with positive growth had decreased to 2.2%. In the DCE group, only 25.6% of the samples revealed bacterial growth. No statistical difference was found between deciduous and permanent molars in any of the treatment groups in terms of microbiologic results (p > 0.05). In conclusion, although none of the treatment methods completely eliminated the viable microorganisms during the initial excavations, a dramatic reduction in bacterial growth was detected during the treatment stages of two-visit IPT. PMID:18548292

Orhan, Ayse I; Oz, Firdevs T; Ozcelik, Berrin; Orhan, Kaan

2008-12-01

326

Estimation of the acentric factor and the liquid molar volume at 298 K using a new group contribution method  

Microsoft Academic Search

The method of Constantinou and Gani [Constantinou, L. and Gani, R., 1994. A new group contribution method for the estimation of properties of pure compounds. AIChE J., 40(10): 1697–1710] is extended to the estimation of the acentric factor and the liquid molar volume at 298 K. Thus, it now allows reliable prediction of all the common corresponding-state physical properties. In

Leonidas Constantinou; Rafiqul Gani; John P. O'Connell

1995-01-01

327

Comparison of Conventional, Rotary, and Ultrasonic Preparation, Different Final Irrigation Regimens, and 2 Sealers in Primary Molar Root Canal Therapy  

Microsoft Academic Search

Purpose: The aim of this study was to compare the shaping effectiveness rotary nickel- titanium (Profi le .04 ISO), ultrasonic (K-Type\\/Satelec), and stainless-steel hand fi le (K-fi le\\/Maillefer) instrumentation and to assess tubular penetration of 2 gutta percha seal- ers (AH Plus and Sealite-Ultra) following 4 different fi nal irrigation regimens in primary molar roots. Methods: Distal roots of extracted

Harun Canoglu; Meryem U. Tekcicek; Zafer C. Cehreli

2006-01-01

328

The chronology of second and third molar development in Koreans and its application to forensic age estimation  

Microsoft Academic Search

The accuracy of forensic age estimation based on the chronology of second (M2) and third molar (M3) development was investigated\\u000a using 2,087 orthopantomograms of Korean men and women aged between 3 and 23 years. The developmental stages of M2s and M3s\\u000a in these subjects were classified using the criteria of Demirjian. Inter-observer reliability and statistical data on each\\u000a stage of mineralization

Sang-Seob Lee; Young-Sub Byun; Myung Jin Park; Jong-Hoon Choi; Chang-Lyuk Yoon; Kyoung-Jin Shin

2010-01-01

329

Influence of the molar ratio of tetraethoxysilane and glycidoxypropyltriethoxysilane on the properties of anhydride-cured epoxy-siloxane composites  

Microsoft Academic Search

The topological structure of epoxy-siloxane composites prepared by anhydride curing was studied in relation to the molar ratio\\u000a of glycidoxypropyltriethoxysilane and tetraethoxysilane and to the total content of siloxane components of the system. The\\u000a optical characteristics, glass transition point, sol fraction yield, concentration of internodal chains, and maximal rate\\u000a of oxygen uptake by the hybrid materials were determined.

S. V. Zhil’tsova; V. M. Mikhal’chuk; V. A. Beloshenko; A. V. Kirilash

2009-01-01

330

Dental Caries and Mutans Streptococci in the Proximal Areas of Molars Affected by the Habitual Use of Xylitol Chewing Gum  

Microsoft Academic Search

The relationship between the caries status and the microbiological status [mutans streptococci (MS)] in the proximal areas of lower right and upper left molars was investigated in subjects of the Ylivieska xylitol study in Finland (1982–1985) in a cross-sectional follow-up in 1988. Those children who had used xylitol chewing gum regularly since 1982 showed significantly lower caries indices in 1988,

P. Isokangas; J. Tenovuo; E. Söderling; H. Männistö; K. K. Mäkinen

1991-01-01

331

Collagen proteins in electrorefining: Rate constants for glue hydrolysis and effects of molar mass on glue activity  

Microsoft Academic Search

Animal glue (collagen proteins) degradation was studied in water and in a simulated copper electrolyte (150 g\\/L H2SO4, 46 g\\/L Cu2+ as CuSO4) by size-exclusion chromatography. The rate of degradation was relatively slow in pure aqueous solutions, and depending on\\u000a the temperature and glue concentration, some association to larger molar mass species was observed. For simulated electrolyte\\u000a in a temperature

M. D. Saban; J. D. Scott; R. M. Cassidy

1992-01-01

332

Change of working length in curved molar root canals after preparation with different rotary nickel-titanium instruments  

PubMed Central

Aim: The purpose of this study was to investigate change of working length in curved molar root canals after preparation with Profile, ProTaper and K3 Rotary Nickel-Titanium (Ni-Ti) instruments. Materials and Methods: One hundred and eighty maxillary and mandibular molars were divided into group I having root curvature angle <300 and group II having root curvature angle >300 comprising 90 teeth in each group based on Schneider's method. Group II and I were further divided into sub group A, B and C having 30 teeth each based on type of instrument used. Profiles, ProTaper and K3 Rotary Ni-Ti files were used to prepare mesial and buccal roots of molars. Radiography platform was made to allow technique for constant object to film distance and object to sensor distance. Conventional access opening was prepared in each tooth. Preoperative and postoperative working length was measured to an accuracy of 0.1 of mm on Dexis 3.0 direct digital radiograph's onscreen measurement device. Results: Mean loss of working length varied from 0.28 to 0.92 mm. Highest working length loss was seen in ProTaper followed by K3 files and Profiles, which is statistically significant. PMID:22025830

Khurana, Pardeep; Nainan, Mohan Thomas; Sodhi, Kiranmeet Kaur; Padda, Bupinder Kaur

2011-01-01

333

Recurrent hydatidiform mole: A case report of six consecutive molar pregnancies complicated by choriocarcinoma, and review of the literature  

PubMed Central

Hydatidiform mole (HM) is the most common form of gestational trophoblastic neoplasia. Recurrence of HM is extremely rare. Here, we report the case of a patient with six consecutive partial HMs without normal pregnancy. A 42-year-old lady who was referred to us at King Fahad Hospital of the University, Al Khobar, initially as a case of 26-year-old with persistent trophoblastic disease after three recurrent molar pregnancies that were confirmed histologically in the referring hospital. She underwent evacuation and curettage and was followed up by serial ?-human chorionic gonadotropin levels, and did not require chemotherapy. She then had three more molar pregnancies in 1995, 1996, and 2004; all molar pregnancies were evacuated by suction curettage at her base hospital, but in the last event, she complained of shortness of breath and abdominal pain. Diagnostic workup in our hospital confirmed choriocarcinoma, for which she received multiple regimen chemotherapy and was cured. Unfortunately, she lately presented with symptoms suggestive of premature menopause. PMID:22175045

Al-Ghamdi, Ahlam A.

2011-01-01

334

Quantitative three-dimensional analysis of root canal curvature in maxillary first molars using micro-computed tomography.  

PubMed

In endodontic therapy, access and instrumentation are strongly affected by root canal curvature. However, the few studies that have actually measured curvature are mostly from two-dimensional radiographs. The purpose of this study was to measure the three-dimensional (3D) canal curvature in maxillary first molars using micro-computed tomography (microCT) and mathematical modeling. Extracted maxillary first molars (46) were scanned by microCT (502 image slices/tooth, 1024 X 1024 pixels, voxel size of 19.5 x 19.5 x 39.0 microm) and their canals reconstructed by 3D modeling software. The intersection of major and minor axes in the canal space of each image slice were connected to create an imaginary central axis for each canal. The radius of curvature of the tangential circle was measured and inverted as a measure of curvature using custom-made mathematical modeling software. Root canal curvature was greatest in the apical third and least in the middle third for all canals. The greatest curvatures were in the mesiobuccal (MB) canal (0.76 +/- 0.48 mm(-1)) with abrupt curves, and the least curvatures were in the palatal (P) canal (0.38 +/- 0.34 mm(-1)) with a gradual curve. This study has measured the 3D curvature of root canals in maxillary first molars and reinforced the value of microCT with mathematical modeling. PMID:16982269

Lee, Jong-Ki; Ha, Byung-Hyun; Choi, Jeong-Ho; Heo, Seok-Mo; Perinpanayagam, Hiran

2006-10-01

335

Effects of active and passive lacebacks on antero-posterior position of maxillary first molars and central incisors.  

PubMed

The purpose of this study was to compare the effects of active and passive lacebacks on antero-posterior position of maxillary first molars and central incisors during leveling phase. Twenty-three subjects with Class I and Class II malocclusion were treated with first premolars extraction using preadjusted appliances (MBT 0.022-inch brackets). The leveling phase was performed with stainless steel archwires only. The sample was divided into 2 groups: 14 subjects received active lacebacks (Group 1) and 9 subjects received passive lacebacks (Group 2). Lacebacks were made from 0.008-inch ligature wire. Lateral cephalometric radiographs were taken pre- and post-leveling phase. Student's t-test was applied to determine the differences between pre- and post-leveling mean values and to determine the mean differences between groups. In Group I, the first molars showed a significant mesial movement, whereas no change was observed in Group 2. In both groups, maxillary central incisor crowns moved to lingual side. In conclusion, active laceback produced anchorage loss of maxillary first molars whereas passive laceback did not affect the position of these teeth. Active and passive lacebacks were effective in preventing central incisor proclination. PMID:23207862

Moresca, Ricardo Cesar; Vigorito, Julio Wilson; Dominguez, Gladys Cristina; Tortamano, André; Moraes, Danielle Rodrigues; Moro, Alexandre; Correr, Gisele Maria

2012-01-01

336

Low-temperature heat capacities and standard molar enthalpy of formation of pyridine-2,6-dicarboxylic acid  

NASA Astrophysics Data System (ADS)

This paper reports that the low-temperature heat capacities of pyridine-2,6-dicarboxylic acid were measured by a precision automatic calorimeter over a temperature range from 78 K to 380 K. A polynomial equation of heat capacities as a function of temperature was fitted by the least-squares method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at intervals of 5 K. The constant-volume energy of combustion of the compound was determined by means of a precision rotating-bomb combustion calorimeter. The standard molar enthalpy of combustion of the compound was derived from the constant-volume energy of combustion. The standard molar enthalpy of formation of the compound was calculated from a combination of the datum of the standard molar enthalpy of combustion of the compound with other auxiliary thermodynamic quantities through a Hess thermochemical cycle.

Yang, Wei-Wei; Di, You-Ying; Kong, Yu-Xia; Tan, Zhi-Cheng

2010-06-01

337

Facile spectrophotometric assay of molar equivalents of N-hydroxysuccinimide esters of monomethoxyl poly-(ethylene glycol) derivatives  

PubMed Central

Background A new method is developed to quantify molar equivalents of N-hydroxysuccinimide (NHS) esters of derivatives of monomethoxyl poly-(ethylene glycol) (mPEG) in their preparations with NHS acetate ester as the reference. Results NHS ester of succinic monoester or carbonate of mPEG of 5,000 Da was synthesized and reacted with excessive ethanolamine in dimethylformamide at 25°C for 15 min. Residual ethanolamine was subsequently quantified by absorbance at 420 nm after reaction with 2,4,6-trinitrobenzenesulfonic acid (TNBS) at pH 9.2 for 15 min at 55°C followed by cooling with tap water. Reaction products of ethanolamine and NHS esters of mPEG caused no interference with TNBS assay of residual ethanolamine. Reaction between ethanolamine and NHS acetate ester follows 1:1 stoichiometry. By the new method, molar equivalents of NHS esters of carbonate and succinic monoester of mPEG in their preparations were about 90% and 60% of their theoretical values, respectively. During storage at 37°C in humid air, the new method detected spontaneous hydrolyses of the two NHS esters of mPEG more sensitively than the classical spectrophotometric method based on absorbance at 260 nm of NHS released by reaction with ammonia in aqueous solution. Conclusion The new method is favorable to quantify molar equivalents of NHS esters of mPEG derivatives and thus control quality of their preparations. PMID:23176729

2012-01-01

338

Open Access Acid Resistance of the Enamel in Primary Second Molars from Children with Down Syndrome and Cerebral Palsy  

E-print Network

Abstract: Objectives: This study was carried out to evaluate the extent of differences in mineralization of inner and outer enamel of the lower primary second molars of children with Down syndrome (DS) and Cerebral Palsy (CP) as revealed by acid treatment of exfoliated teeth. The results were compared to those obtained from a control group of healthy children. Methods: The sample included 4 mandibular second molars from each group. On each tooth, a thin section was cut, bisecting the mesial cusps. The analysis was carried out on the mesio-buccal cusps. Atomic force microscopy (AMF) was used to analyze the morphological structure of the dental enamel after 10 sec of 0.1 mol % citric acid treatment. The measurements were performed on 3 points in the enamel close to the outer surface and 3 points in the enamel close to the dentin. The differences between groups were analyzed using Mann Whitney tests. Results: In controls and CP teeth the outer enamel was more resistant to etching than the inner enamel. In DS teeth both outer and inner enamel showed similar results for all parameters. Between group comparisons showed that roughness values were significantly higher (Penamel reflect increased solubility of the enamel to acid relative to controls and CP teeth together with irregularity of the organic matrix. The practical importance of the results is that DS primary molars needs reduced etching time when prepared for pit and fissure sealants or composite/compomer restorations.

David Keinan; Anna Radko; Patricia Smith; Uri Zilberman

339

Molar size and shape in the estimation of biological ancestry: A comparison of relative cusp location using geometric morphometrics and interlandmark distances.  

PubMed

Human molars exhibit varying shapes when viewed from the occlusal surface. Available methods for quantifying molar occlusal shape have historically been confined to qualitative descriptions. The present study utilized geometric morphometric analyses to capture molar shape as defined through relative cusp locations. Cusp apices of maxillary and mandibular first and second molars were digitized from 190 American Blacks and Whites to estimate biological affinity through the shape of relative cusp locations. The coordinate data were subjected to a Generalized Procrustes Analysis to generate Procrustes coordinates and calculate centroid sizes. Procrustes coordinates were then subjected to a principal component analysis to examine the direction and magnitude of shape change inherent in the sample. Centroid size and major shape component group means were compared with t-tests. Interlandmark distances were then calculated from the raw coordinate information and also subjected to a principal components analysis. Procrustes coordinates and the principal components derived from them with and without centroid size, along with the interlandmark distances and the principal components derived from them, were each subjected to a discriminant function analysis to examine which methods yielded the highest correct classification between population groups. Total correct classifications ranged from 62.7% to 87.9% depending on the variables forward stepwise selected for each analysis. Using a combination of the second maxillary molar and first mandibular molar yielded the most optimistic results and corroborates theoretical models of molar development. PMID:24248428

Kenyhercz, Michael W; Klales, Alexandra R; Kenyhercz, William E

2014-02-01

340

Trial shows partial caries removal is an effective technique in primary molars.  

PubMed

DesignRandomised controlled trial in a university setting.InterventionChildren aged three to eight years, with at least one molar with an acute, deep carious lesion into the dentine were recruited. Treatment took place under rubber dam with decayed dentine being removed completely from the lateral walls of cavities in both groups using round burs operated at low speed. TCR or PCR was then performed in the pulpal wall of each tooth. After caries removal teeth were restored with calcium hydroxide cement and composite resin. Teeth with pulpal exposure were pulpotomised using ferric sulphate.Outcome measureThe presence of a fistula, swelling, spontaneous pain and mobility not compatible with root resorption were considered to be clinical signs of failure. Radiolucency at the furcation or in the periapical region and internal or external pathological resorption were considered to be radiographic signs of failure.ResultsOne hundred and twenty-four teeth in 51 patients were randomised. In the TCR group there were 57 teeth and 38 patients, with 41 patients and 67 teeth in the PCR group. Three patients (four teeth; one PCR and three TCR) dropped out leaving 120 teeth (PCR: n = 66; TCR: n = 54) for analysis. In the TCR group 27.5% (15) teeth in 13 children had pulp exposure compared with one tooth in one child in the PCR group (2%). The mean operative time was significantly higher for TCR (28.1 min; 95% CI: 23.6-32.6 min) than for PCR (17.9 min; 95% CI: 16.3-19.5 min). There was no statistical difference in success rates at 24 months between the groups. The success rate in the TCR group was 96%; (95% CI: 85-99%) compared with 92%; (95% CI: 81-96%) in the PCR group.ConclusionsThe clinical and radiographic success rates of PCR and TCR in primary teeth with deep carious lesions were high and did not differ significantly, indicating that PCR is a reliable minimally invasive approach in primary teeth and that the retention of carious dentine does not interfere with pulp vitality. Moreover, PCR provided other clinically relevant advantages over TCR, especially lower incidence of pulp exposure and lower operative time. PMID:25343394

Santamaria, Ruth; Innes, Nicola

2014-09-01

341

Late postoperative hemorrhage in a patient with undiagnosed COX-1 deficiency after third molar extractions.  

PubMed

Oral maxillofacial surgeons direct invasive procedures that often cause significant bleeding. Uncontrolled hemorrhage is a rare, yet serious, complication that can be seen in patients with thrombocytopathy. Platelets have 3 distinct roles in coagulation: initial adhesion, phospholipid externalization, and platelet aggregation.(1) Several types of platelet deficiencies, including defects of adhesion (Bernard-Soulier syndrome), defects of aggregation (Glanzmann thrombasthenia), and disorders of platelet secretion due to a deficiency of adenosine diphosphate (ADP) or cyclooxygenase-1 (COX-1).(2-4) COX has 2 isoforms: COX-1 and COX-2.(5,6) COX-1 is expressed constitutively in most tissues, and COX-2 is induced primarily by inflammatory mediators.(7,8) Although both isoforms are present in platelets, COX-1 is the major isoform that contributes to coagulation, because it is critically important in the formation of thromboxane A2 (TXA2) by way of the arachidonic acid (AA) pathway.(9) AA is a potent inducer of platelet aggregation.(1,3,4) When AA is exposed to an activating agent, such as ADP, it undergoes a series of enzymatic reactions that culminates in the production of TXA2.(10) TXA2 is the predominant product of the COX-1 pathway and is a major metabolite of AA in platelets. TXA2 is necessary for normal platelet function. Therefore, the inhibition of, or a deficiency in, COX-1 will compromise the AA pathway, thereby reducing platelet secretion and altering normal platelet aggregatory function.(1,3) COX-1 deficiencies are usually caused by drug interactions with the enzyme itself. In addition, studies have identified genetic mutations that can result in COX-1 deficiency.(2) We present the hospital course, management, and diagnosis of a patient with an undiagnosed COX-1 deficiency who had had third molars removed in a private office. To our knowledge, this is the first case of COX-1 deficiency diagnosed after exodontia documented in English studies. In addition, we reviewed the published data of this rare disorder that has significant clinical implications. PMID:24480756

Doscher, Jesse C; Volpe, Fedele N

2014-04-01

342

Microchemical and structural regular variability of apatites in “overbuilt” enamel and dentin of human molar teeth  

NASA Astrophysics Data System (ADS)

The aim of a recent paper was to recognize the chemical and structural changes in apatites, which form both the enamel and the dentin of the human tooth. The aim was achieved by scrutinizing the linear elemental profiles along the cross-sections of human molar teeth. Essentially, the task was accomplished with the application of the Electron Probe Microanalysis method and with some additional studies by Micro-Raman spectrometry. All the trends in linear profiles were strictly determined. In the enamel zone they were either increasing or decreasing curves of exponential character. The direction of the investigations was to start with the tooth surface and move towards the dentin-enamel junction (DEJ). The results of the elemental studies were more visible when the detected material was divided, in an arbitrary way, into the prevailing "core" enamel (˜93.5% of the total mass) and the remaining "overbuilt" enamel. The material in the "core" enamel was fully stable, with clearly determined chemical and mechanical features. However, the case was totally different in the "overbuilt enamel", with dynamic changes in the composition. In the "overbuilt" layer Ca, P, Cl and F profiles present the decaying distribution curves, whereas Mg, Na, K and CO 32- present the growing ones. Close to the surface of the tooth the mixture of hydroxy-, chlor- and fluor-apatite is formed, which is much more resistant than the rest of the enamel. On passing towards the DEJ, the apatite is enriched with Na, Mg and CO 32-. In this location, three of six phosphate groups were substituted with carbonate groups. Simultaneously, Mg is associated with the hydroxyl groups around the hexad axis. In this way, the mechanisms of exchange reactions were established. The crystallographic structures were proposed for new phases located close to DEJ. In the dentin zone, the variability of elemental profiles looks different, with the most characteristic changes occurring in Mg and Na concentrations. Mg content increases more and more when passing deeper in the dentin, while Na content decreases along this route. Na concentration reaches its maximum when it is very close to the DEJ zone. But the carbonate and phosphate spatial distributions inside the dentin refute the potential conclusions drawn from the studies of Mg and Na profiles.

Kuczumow, A.; Nowak, J.; Cha?as, R.

2011-10-01

343

Caries management strategies for primary molars: 1-yr randomized control trial results.  

PubMed

Minimal invasive approaches to managing caries, such as partial caries removal techniques, are showing increasing evidence of improved outcomes over the conventional complete caries removal. There is also increasing interest in techniques where no caries is removed. We present the 1-yr results of clinical efficacy for 3 caries management options for occlusoproximal cavitated lesions in primary molars: conventional restorations (CR; complete caries removal and compomer restoration), Hall technique (HT; no caries removal, sealing in with stainless steel crowns), and nonrestorative caries treatment (NRCT; no caries removal, opening up the cavity, teaching brushing and fluoride application). In sum, 169 children (3-8 yr old; mean, 5.56 ± 1.45 yr) were enrolled in this secondary care-based, 3-arm, parallel-group, randomized clinical trial. Treatments were carried out by specialist pediatric dentists or postgraduate trainees. One lesion per child received CR, HT, or NRCT. Outcome measures were clinical failure rates, grouped as minor failure (restoration loss/need for replacement, reversible pulpitis, caries progression, etc.) and major failure (irreversible pulpitis, abscess, etc.). There were 148 children (87.6%) with a minimum follow-up of 11 mo (mean, 12.23 ± 0.98 mo). Twenty teeth were recorded as having at least 1 minor failure: NRCT, n = 8 (5%); CR, n = 11 (7%); HT, n = 1 (1%) (p = .002, 95% CI = 0.001 to 0.003). Only the comparison between NRCT and CR showed no significant difference (p = .79, 95% CI = 0.78 to 0.80). Nine (6%) experienced at least 1 major failure: NRCT, n = 4 (2%); CR, n = 5 (3%); HT, n = 0 (0%) (p = .002, 95% CI = 0.001 to 0.003). Individual comparison of NRCT and CR showed no statistically significant difference in major failures (p = .75, 95% CI = 0.73 to 0.76). Success and failure rates were not significantly affected by pediatric dentists' level of experience (p = .13, 95% CI = 0.12 to 0.14). The HT was significantly more successful clinically than NRCT and CR after 1 yr, while pairwise analyses showed comparable results for treatment success between NRCT and CR (ClinicalTrials.gov NCT01797458). PMID:25216660

Santamaria, R M; Innes, N P T; Machiulskiene, V; Evans, D J P; Splieth, C H

2014-11-01

344

Making Space for Permanent Molars in Growing Baboon (Papio anubis) and Great Ape (Pan paniscus and P. troglodytes) Mandibles: Possible Ontogenetic Strategies and Solutions  

PubMed Central

While mandible proportions do not appear to constrain permanent molar initiation times, how adequate space is created in the corpus for these teeth in a timely way is not well understood. This question is important for explaining how primate tooth and jaw development and evolution are coordinated. Landmark and linear measurement data were used to characterize mandible shape, growth trajectory, and growth rate between two genera, Papio and Pan, with contrasting permanent molar initiation schedules and mandible proportions. 3D geometric morphometric and 2D bivariate analyses showed genus-level differences in mandible morphology from birth that were amplified by different postnatal growth trajectories. Different corpus proportions and regional variation in corpus growth rates helped create space in a timely way for the molars. Regional corpus growth rates may evolve alongside permanent molar morphology and developmental timing to modify space available in the corpus for these teeth. PMID:22567294

Boughner, Julia C.

2011-01-01

345

Orthodontic treatment combined with tooth transplantation for an adult patient with a missing mandibular first molar: long-term follow-up.  

PubMed

A Japanese woman, age 29 years 8 months, had a missing mandibular left first molar, bimaxillary dentoalveolar protrusion, and crowding. She had a skeletal Class II relationship and a long face with a steep mandible. She had previously undergone root canal treatment for the mandibular right second premolar, and the mandibular left third molar was impacted. The maxillary left first premolar was extracted for autotransplantation to the mandibular left first molar region. After confirmation of a favorable prognosis for the transplanted tooth, the maxillary right first premolar, the mandibular right second premolar, and the impacted mandibular left third molar were extracted for orthodontic treatment. The active orthodontic treatment period was 32 months. The patient returned for follow-up records 12 years 7 months after the active treatment, and her facial profile and occlusion were well maintained. At 13 years 9 months after transplantation, no abnormalities were observed with the transplanted tooth in the radiographic and clinical evaluations. PMID:24680019

Watanabe, Yohei; Mohri, Tamaki; Yoshida, Rumi; Yamaki, Masaki; Saito, Isao

2014-04-01

346

Efficacy of low-level laser therapy in the management of pain, facial swelling, and postoperative trismus after a lower third molar extraction. A preliminary study  

Microsoft Academic Search

Pain, swelling, and trismus are the most common complications after surgical removal of impacted lower third molars. The aim\\u000a of this study was to evaluate the analgesic and anti-inflammatory effects of a low-level laser therapy (Laser Smile™, Biolase®,\\u000a San Clemente, USA) applied to the wound appeared after the surgical removal of impacted lower third molars. A prospective,\\u000a randomized, and double-blind

Marta López-Ramírez; Miguel Ángel Vílchez-Pérez; Jordi Gargallo-Albiol; Josep Arnabat-Domínguez; Cosme Gay-Escoda

347

Determination of Frequency of the Second Mesiobuccal Canal in the Permanent Maxillary First Molar Teeth with Magnification Loupes (x 3.5)  

PubMed Central

INTRODUCTION: The mesiobuccal root of the maxillary first molar has generated more research and clinical investigation than any root. An inability to detect and treat a second mesiobuccal (MB2) canal is a reason for endodontic failure in maxillary first molars. Modifications in the endodontic access and detection techniques, along with advancements in illumination and magnification technology, have aided in the location and treatment with the second mesiobuccal canal of maxillary first molars. OBJECTIVE: To determine the frequency of the second mesiobuccal canal in the permanent maxillary first molars with magnification loupes (× 3.5). MATERIALS AND METHODS: A total of 53 teeth were assessed using a moderate magnification for second mesiobuccal canal in mesiobuccal root of first permanent maxillary molars in vivo. Detection of this canal in maxillary first molars was done through a clinical access cavity preparation under magnification loupes (× 3.5). Data was analyzed using SPSS 15.0. Frequency distribution of variables was determined and the level of significance was kept at 0.05. RESULTS: We were able to detect second mesiobuccal canal in 27 out of 53 (50.9%) of the permanent maxillary first molars that were studied. It was found that the males tend to have a higher proportion of second mesiobuccal canals (up to 31%) as compared to the females in whom the second mesiobuccal canals could be identified only 19% of the time. Whilst, there was no association found between age, gender and chamber obliteration with the presence of second mesiobuccal canal. CONCLUSIONS: In conclusion, within its limitations, this study suggested that the use of magnification loupes enhanced both the detection (50.9%) and negotiation (86.8%) of the second mesiobuccal canals in the permanent maxillary first molars beyond what could be achieved with naked eye.

Hasan, Muhammad; Raza Khan, Farhan

2014-01-01

348

Thermodynamic properties of alcohols in a micellar phase. Binding constants and partial molar volumes of pentanol in sodium dodecylsulfate micelles at 15, 25, and 35°C  

Microsoft Academic Search

Densities of the ternary system water-sodium dodecylsulfate (NaDS)-pentanol and of the binary systems butanol-octane and pentanol-octane were measured at 15, 25, and 35 °C. The apparent molar volume of pentanol in the ternary system was analyzed using a mass-action model for the alcohol distribution in micellar solutions. The partial molar volume of alcohol bound to the micelles and the ratio

Rosario De Lisi; Calogero Genova; Rosaria Testa; Vincenzo Turco Liveri

1984-01-01

349

Determination of the Relative Partial Molar Enthalpy of Decyldimethylphospine Oxide in H 2O and D 2O at 25°C  

Microsoft Academic Search

The relative partial molar enthalpy of decyldimethylphosphine oxide has been determined in H2O and D2O from infinite dilution to about 8 mm at 25°C. The shapes of the resulting curves resemble those previously reported forionicbut notnonionicsurfactants and are inconsistent with existing models of micelle formation. The enthalpy of micelle formation (corresponding to the maximum value of the relative partial molar

Gordon C. Kresheck

1997-01-01

350

Molecular polarizability of organic compounds and their complexes: LII. Molar volumes of polymeric compounds in solutions, extrapolated to infinite dilution, and steric structure of their molecules  

Microsoft Academic Search

The molar volumes in solutions at infinite dilution were determined for a series of vinyl, glycol, isoprene, and cyclopentadiene\\u000a polymers and oligomers with various degrees of polymerization. An additive analysis of the molar volumes showed that molecules\\u000a of vinyl, ethylene glycol, and isoprene polymers exist in solutions in elongated helical conformations. In the majority of\\u000a polymer molecules, except polystyrenes, polyisoprenes,

S. B. Bulgarevich; T. V. Burdastykh; M. V. Boiko

2007-01-01

351

The Inter-Relationship between Dietary and Environmental Properties and Tooth Wear: Comparisons of Mesowear, Molar Wear Rate, and Hypsodonty Index of Extant Sika Deer Populations  

PubMed Central

In reference to the evolutionary trend of increasing cheek tooth height in herbivorous ungulates, the causes of dental abrasion have long been debated. Interspecific comparisons of extant ungulates have revealed that both phytoliths in grass and external abrasive matter may play important roles. Using analysis of extant sika deer living in various environments and showing continuous latitudinal variation in food habits from northern grazing to southern browsing, we quantitatively evaluated the influence of dietary and environmental properties on three dental variables: mesowear score (MS), molar wear rate, and M3 hypsodonty index. We used 547 skulls and 740 mandibles from 16 populations of sika deer to obtain the dental measurements. We found that only graminoid proportion in diet correlated with MS and the molar wear rate, implying that phytoliths in grass abrade dental tissues. In contrast, annual precipitation in habitat was not correlated with any of the dental variables. We also found a significant correlation between the molar wear rate (selective pressure for high-crowned molars) and the M3 hypsodonty index of extant sika deer, implying an evolutionary increment in molar height corresponding to the molar wear rate. Our intraspecific comparative analyses provide further support for use of mesowear analysis as a paleodiet estimation method; it not only reveals staple food types (graminoids or dicots) but also implies regional or seasonal variation in the diet of the species. PMID:24603896

Kubo, Mugino Ozaki; Yamada, Eisuke

2014-01-01

352

Effects of mineral trioxide aggregate and formocresol on vital pulp after pulpotomy of primary molars: An in vivo study  

PubMed Central

Background: Preservation of pulp vitality is of utmost importance to the normal physiological functioning of tooth in situ and physiological process of exfoliation in a tooth affected by disease or trauma. Pulpotomy serves such a purpose using various medicaments applied directly on vital pulp. Aim: The aim of this study was to evaluate clinically and radiographically the effects of mineral trioxide aggregate (MTA) and formocresol (FC) as a pulp dressing after coronal pulp amputation (pulpotomy) in primary molars prospectively over a period of 1 year. Materials and Methods: Thirty-three healthy children, aged between 5 and 8 years, requiring pulp therapy were selected after clinical and radiographic assessment. A total of 50 maxillary and mandibular primary molars were treated by the conventional pulpotomy technique. The teeth were divided into two equal groups. In Group A, FC was used as the pulp dressing agent, and in Group B, MTA was used before restoration with stainless steel crowns. The research employed was a prospective study. The teeth treated were assessed postoperatively after 1, 3, 6 and 12 months. The observations were tabulated and statistically analyzed. Results: Clinically, both the groups showed 100% success at 1, 3, 6 and 12 months. At 3 months, the radiographic success rates of FC and MTA were 92% and 96%, respectively, and at 6 and 12 months, the radiographic success rates of FC and MTA were 88% and 96%, respectively. Conclusion: MTA showed a higher success rate than FC and may be a favorable material for pulpotomy in primary molars whose pulps have been compromised by a carious or mechanical pulp exposure PMID:22346156

Godhi, Brinda; Sood, P. B.; Sharma, Arun

2011-01-01

353

Analysis of the dental morphology of Plio-pleistocene hominids. I. Mandibular molars: crown area measurements and morphological traits.  

PubMed Central

This study has used accurate measurements of crown area and precise assessments of the morphological traits of mandibular molars in an attempt to define the metrical and morphological characteristics of early hominid taxa. A total of 196 Plio-Pleistocene hominid molars were either allocated to one of six informal taxonomic groups or considered as individual cases. Accurate measurements of crown base area made from occlusal photographs have enabled us to estimate the effects of interproximal wear on crown areas. The average correction factor over the three molar types is around 2-4% with a maximum of 6%. The patterns of distribution of extra cusps show interesting differences between taxa. None of the M-1S in the two groups of 'gracile' hominids from East and South Africa bears a C6, but it is common in the two 'robust' taxa. The distribution of a C7 is the reverse of this, it being rare in the robust' taxa, and more common in the 'gracile' groups. There is thus no simple relationship between cusp number and tooth size. Our observations on the protostylid suggest that though it is more common in the 'robust' australopithecines than the 'graciles', when it does occur it is more strongly expressed in the 'gracile' group. The combination of simple metrical data, and the assessment of morphological traits, can help in the classification of enigmatic or incomplete specimens. Some isolated teeth from the collection at Koobi Fora can confidently be assigned to Australopithecus boisei, and useful guides have been provided for taxonomic assessment of the skull KNM-ER 1805, and the mandibles KNM-ER 1506 and 1820. PMID:6403498

Wood, B A; Abbott, S A

1983-01-01

354

Half-molar sodium lactate infusion improves cardiac performance in acute heart failure: a pilot randomised controlled clinical trial  

PubMed Central

Introduction Acute heart failure (AHF) is characterized by inadequate cardiac output (CO), congestive symptoms, poor peripheral perfusion and end-organ dysfunction. Treatment often includes a combination of diuretics, oxygen, positive pressure ventilation, inotropes and vasodilators or vasopressors. Lactate is a marker of illness severity but is also an important metabolic substrate for the myocardium at rest and during stress. We tested the effects of half-molar sodium lactate infusion on cardiac performance in AHF. Methods We conducted a prospective, randomised, controlled, open-label, pilot clinical trial in 40 patients fulfilling two of the following three criteria for AHF: (1) left ventricular ejection fraction <40%, (2) acute pulmonary oedema or respiratory failure of predominantly cardiac origin requiring mechanical ventilation and (3) currently receiving vasopressor and/or inotropic support. Patients in the intervention group received a 3 ml/kg bolus of half-molar sodium lactate over the course of 15 minutes followed by 1 ml/kg/h continuous infusion for 24 hours. The control group received only a 3 ml/kg bolus of Hartmann’s solution without continuous infusion. The primary outcome was CO assessed by transthoracic echocardiography 24 hours after randomisation. Secondary outcomes included a measure of right ventricular systolic function (tricuspid annular plane systolic excursion (TAPSE)), acid-base balance, electrolyte and organ function parameters, along with length of stay and mortality. Results The infusion of half-molar sodium lactate increased (mean?±?SD) CO from 4.05?±?1.37 L/min to 5.49?±?1.9 L/min (P?molar sodium lactate improved cardiac performance and led to metabolic alkalosis in AHF patients without any detrimental effects on organ function. Trial registration Clinicaltrials.gov NCT01981655. Registered 13 August 2013. PMID:24666826

2014-01-01

355

Air Oxidation of FeCoNi-Base Equi-Molar Alloys at 800–1000°C  

Microsoft Academic Search

The oxidation behavior of FeCoNi, FeCoNiCr, and FeCoNiCrCu equi-molar alloys was studied over the temperature range 800–1000 °C in dry air. The ternary and quaternary alloys were single-phase, while the quinary alloy was two-phase. In general, the oxidation kinetics of the ternary and quinary alloys followed the two-stage parabolic rate law, with rate constants generally increasing with temperature. Conversely, three-stage parabolic

W. Kai; W. L. Jang; R. T. Huang; C. C. Lee; H. H. Hsieh; C. F. Du

2005-01-01

356

Excess partial molar volumes and thermal expansivities in the water-rich region of aqueous 2-butanone  

Microsoft Academic Search

Excess partial molar volumes of 2-butanone VmE(B) and thermal expansivities ap were measured in the water-rich region of aqueous 2-butanone. The composition derivatives of both quantities showed anomalies at about XB=0.033 (xB is the mole fraction of B).\\u000a$$(\\\\partial V_m^E (B)\\/\\\\partial n_B )_{p,T,n_w }$$\\u000a showed a step anomaly, while\\u000a$$(\\\\partial \\\\alpha _p \\/\\\\partial n_B )_{p,T,n_w }$$\\u000a exhibited a peak anomaly.

James V. Davies; Robert Fooks; Yoshikata Koga

1994-01-01

357

Densities and excess molar volumes for mixtures of methanol with other alcohols at temperatures (288.15–313.15 K)  

Microsoft Academic Search

Densities have been measured for the binary mixtures of methanol with ethanol, isomers of propanol and butanol over the entire\\u000a composition range at 288.15, 293.15, 298.15, 303.15, 308.15, 313.15 K. The density data have been used to calculate the molar\\u000a volumes, thermal expansion coefficients and their excess values. The excess parameters have been fitted to the Redlich–Kister\\u000a polynomial equation. The values

Agnieszka Boru?; Ma?gorzata ?urada; Adam Bald

2010-01-01

358

Incidence of neurosensory deficits and recovery after lower third molar surgery: a prospective clinical study of 4338 cases.  

PubMed

A prospective study of all lower third molar surgery performed in the outpatient extraction clinic of a teaching dental hospital was conducted from January 1998 through October 2005 to determine the incidence of subsequent neurosensory deficit due to inferior alveolar nerve (IAN) and lingual nerve (LN) injury, to examine possible contributing risk factors and to describe the pattern of recovery. 3595 patients were included (61% female, 39% male; age range, 14-82 years). Of the 4338 lower third molar extractions performed by various grades of operators, 0.35% developed IAN deficit and 0.69% developed LN deficit. Distoangular impaction was found to increase the risk of LN deficit significantly (p<0.001). Depth of impaction was related to the risk of IAN deficit (p<0.001). Undergraduates caused more LN deficits (p<0.001). Sex, age, raising of a lingual flap, protection of LN with a retractor, removal of distolingual cortex, tooth sectioning and difficulty in tooth elevation were not significantly related to IAN or LN injury. Postoperative recovery from IAN and LN deficits was noted most significantly at 3 and 6 months, respectively. By the end of the follow-up period, 67% of IAN deficits and 72% of LN deficits had recovered completely. PMID:20061121

Cheung, L K; Leung, Y Y; Chow, L K; Wong, M C M; Chan, E K K; Fok, Y H

2010-04-01

359

A clinical evaluation of a bioresorbable membrane and porous hydroxyapatite in the treatment of human molar class II furcations  

PubMed Central

Background: The ultimate goal of periodontal therapy is predictable regeneration of a functional attachment apparatus destroyed as a result of periodontitis. Reconstructive procedures have been used with varying success during the past decades to accomplish this goal. Aim: To evaluate whether the use of porous hydroxyapatite alone or a bioresorbable membrane alone would enhance the clinical results in the treatment of class II furcation defects in human lower molars. Materials and Methods: Fifteen patients with chronic periodontitis, aged between 39 and 49 years, with a pair of similar bilateral class II furcation defects (classification of Hamp et al.) in mandibular first molars were selected. A split-mouth design was incorporated and the selected 30 furcation defects were assigned to one of the two treatment groups, i.e., Group I treated with a bioresorbable membrane from bovine-derived collagen guided tissue regeneration membrane and Group II treated using porous hydroxyapatite bone graft material on the contralateral sides. Evaluation of clinical parameters, probing depths and attachment levels, and radiographs was done preoperatively and 6 months postoperatively. Results: Both the groups showed statistically significant mean reduction in probing depths and gain in clinical attachment levels and linear bone fill. Comparison between Group I and Group II showed insignificant difference. Conclusion: Within the limits of this study, both the treatment modalities are beneficial for the treatment of human mandibular class II furcation defects. PMID:24174756

Malathi, K. Gita; Dev, J. Narendra; Kumar, K. Suresh; Srikanth, Chitta; Ravi Chandra, P. V.; Paul, Arpita

2013-01-01

360

Correlation of the Radiographic and Morphological Features of the Dental Follicle of Third Molars with Incomplete Root Formation  

PubMed Central

The objective of this study was to determine the correlation of the radiographic and morphological features of the dental follicle of unerupted third molars with incomplete root formation. A cross-sectional study was carried out with 56 patients (105 teeth) aged 13 to 24 years. Panoramic radiography was used to determine the stage of root formation to locate and measure pericoronal radiolucency. The width of the dental follicle ranged from 0.0 to 4.0 mm, the distal face being the one most frequently involved, and stage 7 of root formation showing the highest incidence. An inactive enamel reduced epithelium and inactive epithelium remnant also showed a high incidence. Dense connective tissue showed a high incidence, chronic inflammation was infrequent and calcification was a common finding. There was a significant association between the progression of the rhizogenesis and the transformation of the enamel reduced epithelium into a stratified squamous epithelium. No significant association was found between rhizogenesis and the other morphological findings or between the latter and the width of the pericoronal space. It was concluded that there was no clinically significant correlation between the radiographic and morphological features. Every asymptomatic unerupted third molar should be followed up and the follicular tissue analyzed. PMID:18311329

de OLIVEIRA, David Moraes; de Souza ANDRADE, Emanuel Sávio; da SILVEIRA, Márcia Maria Fonseca; CAMARGO, Igor Batista

2008-01-01

361

Pre-emptive analgesia with the combination of tramadol plus meloxicam for third molar surgery: a pilot study.  

PubMed

The aim of this pilot study was to evaluate pre-emptive analgesia using the combination tramadol plus meloxicam compared with each individual drug alone for the reduction of pain after extraction of third molars. Fifty-one patients were randomised into three groups (n=17 in each), using a series of random numbers: the first group was given tramadol 25mg and meloxicam 7.5mg; the second tramadol 50mg, and the third meloxicam 15 mg, all intramuscularly. Treatments were prepared in identical syringes by an independent investigator and were given immediately. The teeth were removed 50 min after the analgesics had been given. Intensity of pain, consumption of analgesics, and adverse effects were evaluated. The intensity of pain was evaluated using a visual analogue scale (VAS) and the area under the curve of the VAS showed significant differences amongst the groups. In conclusion, the study showed that the combination of tramadol 25mg and meloxicam 7.5mg had an analgesic effect similar to that of meloxicam 15 mg, but both were better than tramadol 50mg for relief of pain after the extraction of mandibular third molars. PMID:22222224

Isiordia-Espinoza, Mario Alberto; Sánchez-Prieto, Martín; Tobías-Azúa, Francisco; Reyes-García, Juan Gerardo; Granados-Soto, Vinicio

2012-10-01

362

Collagen proteins in electrorefining: Rate constants for glue hydrolysis and effects of molar mass on glue activity  

NASA Astrophysics Data System (ADS)

Animal glue (collagen proteins) degradation was studied in water and in a simulated copper electrolyte (150 g/L H2SO4, 46 g/L Cu2+ as CuSO4) by size-exclusion chromatography. The rate of degradation was relatively slow in pure aqueous solutions, and depending on the temperature and glue concentration, some association to larger molar mass species was observed. For simulated electrolyte in a temperature range of 42 °C to 70 °C and a glue concentration range of 100 to 3000 mg/L, the degradation rate constant was described with the following relation: k' = 1.5· 107exp (-9951 /T), min-1 The degradation rate was zero order with respect to initial concentration of the protein and first order with respect to acid concentration. The results show that glue degradation under normal tankhouse operation should be rapid, with degradation to number-average molar mass (M n ) < 10,000 units occurring in about 40 to 80 minutes depending on the mass transfer rate (or mixing) of the electrolyte solution. Samples of glue from three different sources showed almost no difference in degradation rates. Results calculated from the rate equation for glue degradation have been correlated with cathode polarization data from the literature, and the results suggest that critical glue M n below which the glue loses most of its activity is 3700.

Saban, M. D.; Scott, J. D.; Cassidy, R. M.

1992-03-01

363

Thermodynamics of aqueous zinc: Standard partial molar heat capacities and volumes of Zn 2+(aq) from 10 to 55°C  

NASA Astrophysics Data System (ADS)

The apparent molar heat capacities and volumes of aqueous Zn(ClO 4) 2 have been measured from 10-55°C in a Picker flow microcalorimeter and vibrating tube densimeter. The Guggenheim form of the extended Debye-Hückel equation was fitted to the experimental data, to obtain the following expressions for the standard-state properties from 10-55°C: C p0(Zn(ClO 4) 2, aq)/JK -1 mol -1 = 3850.8 - 150720/T-190 - 8.4956T (1) and V 0(Zn(ClO 4) 2, aq)/cm 3 mol -1 = 116.65 - 4073/T-190- 0.050374T . (2) The standard partial molar heat capacities and volumes for Zn 2+(aq) were extrapolated to higher temperatures by employing the Helgeson-Kirkham-Flowers (HKF) equations, amended to include a standardstate correction term. Gibbs energies calculated from the extrapolated heat capacity and volume functions are consistent with limited experimental data for the solubility of ZnO in acidic to near-neutral aqueous solutions at 200-300°C ( BOURCIER and BARNES, 1987).

Pan, Pujing; Tremaine, Peter R.

1994-11-01

364

The efficacy of 2 different doses of dexamethasone to control postoperative swelling, trismus, and pain after third molar extractions.  

PubMed

This article addresses the effect of 2 different concentrations (4 and 12 mg) of dexamethasone to control pain, swelling, and trismus after third molar surgery. A clinical study was conducted with 27 male and female patients, all presenting with bilaterally displaced mandibular third molars. The treatment protocol required a surgical removal of each tooth in 2 separate operations. The patients were given a preoperative dose of dexamethasone-4 mg for one surgery, 12 mg for the other. The choice of which side would be operated on first and which dose of dexamethasone would be taken was performed randomly, under double-blind conditions. The trismus was assessed by measuring the interincisal distance. Pain intensity was measured both by the amount of painkillers (acetaminophen 750 mg) taken postsurgery and by the Visual Analogue Pain Scale. Data were collected 1 hour preoperative, then at 24 and 48 hours postoperative. A statistical analysis (student's t, Wilcoxon and Friedman tests) of the results showed no significant differences (? = 0.05) between the analyzed variables for the 2 doses of dexamethasone (4 and 12 mg). PMID:25369393

Agostinho, Cicero Newton Lemos Felicio; da Silva, Vanessa Camila; Maia Filho, Etevaldo Matos; Cruz, Maria Luiza; Bastos, Eider Guimaraes

2014-01-01

365

Crown size and cusp proportions in Homo antecessor upper first molars. A comment on Quam et al. 2009  

PubMed Central

A recent evaluation of upper first molar (M1) crown size and cusp proportions in the genus Homo (Quam et al. 2009) describes Homo antecessor as maintaining a primitive pattern of cusp proportions, similar to that identified in australopithecines and the earliest members of the genus Homo. These results contrast with those of Gómez-Robles et al. (2007), who described the crown shape in these molars as derived and similar to Neanderthals and European Homo heidelbergensis. The reassessment of these measurements following the same methodology described by Quam et al. (2009) in all the M1s that are currently part of the hypodigm of H. antecessor demonstrates that the fossils from TD6 not only have the same cusp proportions identified in later Homo species, but also a strongly reduced metacone and a large hypocone shared with Middle and Upper Pleistocene members of the Neanderthal lineage. The evolutionary significance of these features should be evaluated in light of the results provided by recently discovered dental, cranial, mandibular, and postcranial H. antecessor fossils. PMID:21208207

Gomez-Robles, Aida; de Castro, Jose Maria Bermudez; Martinon-Torres, Maria; Prado-Simon, Leyre

2011-01-01

366

Comparison of two incision designs for surgical removal of impacted mandibular third molar: A randomized comparative clinical study  

PubMed Central

Objective: The objective of this study is to investigate the influence of flap design on visibility and accessibility during removal of impacted third molar and hematoma formation, wound gaping and healing of flap post-operatively. Study Design: The randomized prospective comparative study included 30 patients with impacted mandibular third molars. Two flap designs namely envelope flap (Koener's incision) and ‘triangular flap’ (Ward's incision) were used. After 7 days, sutures were removed and status of wound, periodontal health, and progress of healing was assessed. Patients were followed through 15 days to judge the incidence of post-operative complications in both groups. Results: No statistical differences were noted between the groups in terms of visibility, accessibility, excessive bleeding during surgery, healing of flap, sensitivity of adjacent teeth, and dry socket. A statistically significant difference was observed in post-operative hematoma, wound gaping, and distal pocket in adjacent tooth, which was significant in Ward's triangular incision group in comparison to Koeiner's envelope incision group. Conclusion: The selection of the flap design is dependent on needs of the case and preference of the operating surgeon and does not seem to have a significant influence on the health of tissues. In order to avoid wide area of exposure of bone, the operating surgeon should clinically and radiographically assess the designing of incision and mucoperiosteal flap, the clinical relevance is still debatable. PMID:24963241

Desai, Adarsh; Patel, Rushit; Desai, Kiran; Vachhani, Nirav Bharatbhai; Shah, Kruti A; Sureja, Raj

2014-01-01

367

Selenium and mercury molar ratios in saltwater fish from New Jersey: Individual and species variability complicate use in human health fish consumption advisories?  

PubMed Central

Balancing risk versus benefits to humans and other organisms from consuming fish is a national concern in the USA, as well as in many other parts of the world. Protecting public health is both a federal and state responsibility, and states respond by issuing fish consumption advisories, particularly for mercury. Recently it has been emphasized that the protective role of selenium against mercury toxicity depends on their molar ratios, which should be evaluated as an indication of selenium’s protective capacity, and incorporated in risk assessments for fish consumption. However, there is no single “protective” ratio agreed upon. In this paper we examine the selenium:mercury (Se:Hg) molar ratios in a wide range of saltwater fish caught and eaten by recreational fishers along the New Jersey coast. We were particularly interested in interspecific and intraspecific variability, and whether the molar ratios were consistent within a species, allowing for its use in managing risk. The selenium–mercury molar ratio showed significant variation among and within fish species. The molar ratio decreased with the size of the fish species, decreased with the mercury levels, and within a fish species, the selenium:mercury ratio decreased with fish size. As an essential element, selenium undergoes some homeostatic regulation, but it is also highly toxic. Within species, mercury level tends to increase with size, accounting for the negative relationship between size and ratio. This variability may make it difficult to use the selenium:mercury molar ratio in risk assessment, risk management, and risk communication at this time, and more information is needed on how mercury and selenium actually interact and on the relationship between the molar ratios and health outcomes. PMID:22405995

Burger, Joanna; Gochfeld, Michael

2014-01-01

368

Dental caries in primary and permanent molars in 7-8-year-old schoolchildren evaluated with Caries Assessment Spectrum and Treatment (CAST) index  

PubMed Central

Background No reports on a caries pattern covering the full spectrum of the disease could be found in the literature. The aim of this study was to evaluate caries in primary and first permanent molars of 7-8-year-old Polish children by the Caries Assessment Spectrum and Treatment (CAST) index and to find whether there was any correlation between the caries stages in such teeth. Methods The study covered 284 7-8-year-old children from randomly selected schools in the Bialystok District, Poland. The prevalence of CAST categories was evaluated with regard to the first and second primary, and first permanent, molars. The Spearman’s rank correlation coefficient was used to explore the correlation of the distribution of CAST codes among the evaluated teeth. The level of statistical significance was established at p?molars, caries was observed in 14.8% to 17.3% of the molar and most lesions were scored at the non-cavitation level. Caries in primary molars was most often recorded at the stage of cavitated dentine lesion. Teeth with pulpal involvement, sepsis and extracted due to caries were found to be more prevalent in first, and then in second primary molars. A strong correlation was found between the status of teeth from the right and left sides of the oral cavity. The correlation of the status of first and second primary teeth was stronger for the left than for the right side of the mouth, r was 0.627 and 0.472 in maxilla and 0.513 and 0.483 in mandible (p?molars the correlation was assessed to be weak. With regard to the teeth situated in opposite jaws the study revealed that the correlations were moderate - r between 0.33 and 0.49. The intra-examiner reliability was established at 0.96 for the primary dentition and at 0.878 for permanent molars. Conclusion The strongest correlation found in the evaluated population concerned the distribution of caries in primary molars on the left side of the mouth. The study proved the usefulness of the CAST index in epidemiological surveys. PMID:24952612

2014-01-01

369

Correlation of panoramic radiographs and spiral CT scan in the preoperative assessment of intimacy of the inferior alveolar canal to impacted mandibular third molars.  

PubMed

Iatrogenic origin of neurosensory dysfunction is a distressing sequel to the surgical removal of impacted mandibular third molars, which is frequently overlooked. According to various surveys, the rate of neurologic complications related to the surgical removal of impacted mandibular third molars varies between 0.5% and 1% for permanent damage and 5% and 7% involving temporary damage. Prevention always stands as the best modality to avoid patient's discomfort and lawsuits by sophisticated consumerism.Preoperative assessment of the topographic relationship of the impacted mandibular third molar to the inferior alveolar canal has been performed by different imaging modalities. However, none of the imaging techniques give cent percent information. The best available imaging modality in time and resources should be adopted by the surgeon to avoid complications and lawsuits. Orthopantomography has often been cited as the imaging modality of choice before surgical removal of impacted mandibular third molar. However, it depicts a two-dimensional view of an intricate three-dimensional anatomic relationship and also fails to accurately project the buccolingual relation between the tooth and the inferior alveolar canal. The current study was designed to evaluate the potential advantages of spiral computed tomography and compare its efficacy as a presurgical planning tool with orthopantomography in patients with impacted mandibular third molars showing proximity to the inferior alveolar canal on an orthopantomogram. PMID:21403569

Khan, Imran; Halli, Rajshekhar; Gadre, Pushkar; Gadre, Kiran S

2011-03-01

370

Composite bone graft for treatment of osseous defects after surgical removal of impacted third and second molars: case report and review of the literature.  

PubMed

The aim of this case report was to evaluate the clinical and radiographic measurements of mandibular first molar bone support after mandibular third and second molar extraction and immediate augmentation of the extraction site with a combined autogenous bone graft with Bio-Oss materials. A pyramidal full-thickness mucoperiosteal flap with 1 distal releasing incision was used for removal of impacted third and second molars. During the procedure, autogenous bone graft was collected with a bone trap and then combined with Bio-Oss materials. The osseous defects distal to first molar and extraction site was filled with the composite bone graft and covered with Bio-Gide membrane. After 1 year, there was a successful defect regression and gain of bone and clinical attachment level. Moreover, there was a reduction of probing pocket depth and gingival inflammation. From the results of this study, it can be concluded that grafting of osseous defects and extraction site with autogenous bone graft combined with Bio-Oss materials will predictably result in a decreased risk of developing a periodontal defect on the distal aspect of mandibular first molar. PMID:21784674

Hassan, Khalid S; Marei, Hesham F; Alagl, Adel S

2011-12-01

371

Molar Absorptivity and Concentration-Dependent Quantum Yield of Fe(II) Photo-Formation for the Aqueous Solutions of Fe(III)-Dicarboxylate Complexes  

NASA Astrophysics Data System (ADS)

Redox cycles of iron in the aquatic environment affect formation of reactive oxygen species such as hydrogen peroxide and hydroxyl radicals, which in turn determines lifetimes of many organic compounds. Although aqueous Fe(III)-dicarboxylate complexes are considered to be important sources of photo-formed Fe(II), molar absorptivity and quantum yield of Fe(II) formation for individual species are not well understood. We initiated a study to characterize Fe(II) photo-formation from Fe(III)-dicarboxylates with the concentration ranges that are relevant to the natural aquatic environment. The Visual MINTEQ computer program was used to calculate the equilibrium concentrations of individual Fe(III)-dicarboxylate species. The molar absorptivity of Fe(III)-dicarboxylate species was obtained by UV-VIS spectrophotometer, and the product of the quantum yield and the molar absorptivity of Fe(III)-dicarboxylate species were obtained from photochemical experiments. These experimental data were combined with the calculated equilibrium Fe(III)-dicarboxylate concentrations to determine individual molar absorptivity and quantum yield of Fe(II) photo-formation for a specific Fe(III)-dicarboxylate species. We used initial concentrations of less than 10 micromolar Fe(III) to study the photochemical formation of Fe(II). Dicarboxylate compounds studied include oxalate, malonate, succinate, malate, and phthalate. We report molar absorptivity and concentration-dependent quantum yields of Fe(II) photo-formation of individual Fe(III)-dicarboxylates.

Hitomi, Y.; Arakaki, T.

2009-12-01

372

GENERAL: Low-temperature heat capacities and standard molar enthalpy of formation of N-methylnorephedrine C11H17NO(s)  

NASA Astrophysics Data System (ADS)

This paper reports that low-temperature heat capacities of N-methylnorephedrine C11H17NO(s) have been measured by a precision automated adiabatic calorimeter over the temperature range from T = 78 K to T = 400K. A solid to liquid phase transition of the compound was found in the heat capacity curve in the temperature range of T = 342-364 K. The peak temperature, molar enthalpy and entropy of fusion of the substance were determined. The experimental values of the molar heat capacities in the temperature regions of T = 78-342 K and T = 364-400 K were fitted to two polynomial equations of heat capacities with the reduced temperatures by least squares method. The smoothed molar heat capacities and thermodynamic functions of N-methylnorephedrine C11H17NO(s) relative to the standard reference temperature 298.15 K were calculated based on the fitted polynomials and tabulated with an interval of 5 K. The constant-volume energy of combustion of the compound at T = 298.15K was measured by means of an isoperibol precision oxygen-bomb combustion calorimeter. The standard molar enthalpy of combustion of the sample was calculated. The standard molar enthalpy of formation of the compound was determined from the combustion enthalpy and other auxiliary thermodynamic data through a Hess thermochemical cycle.

Di, You-Ying; Wang, Da-Qi; Shi, Quan; Tan, Zhi-Cheng

2008-08-01

373

A new mammal skull from the Lower Cretaceous of China with implications for the evolution of obtuse-angled molars and 'amphilestid' eutriconodonts  

PubMed Central

We report the discovery of Juchilestes liaoningensis, a new genus and species of eutriconodont mammal from the Lujiatun Site of the Lower Cretaceous Yixian Formation (123.2 ± 1.0 Ma; Lower Aptian). The holotype preserves a partial skull and full dentition. Among eutriconodonts, its lower dentition is similar to taxa formerly assigned to the paraphyletic group of ‘amphilestids’. Some have considered ‘amphilestid’ molars to represent the structural intermediate between the lower molars of the ‘triconodont’ pattern of cusps in alignment and the fully triangulate and more derived therian molars. However, ‘amphilestid’ taxa were previously represented only by the lower dentition. Our study reveals, for the first time, the upper dentition and skull structure of an ‘amphilestid’, and shows that at least some eutriconodonts have an obtuse-angled cusp pattern on molars in middle positions of the long molar series. Its petrosal is similar to those of other eutriconodonts and spalacotheroid ‘symmetrodonts’. Our phylogenetic analyses suggest that (i) Juchilestes is most closely related to the Early Cretaceous Hakusanodon from Japan, in the same Eastern Asiatic geographic region; (ii) ‘amphilestids’ are not monophyletic; and (iii) eutriconodonts might not be a monophyletic group, although this hypothesis must be further tested. PMID:19726475

Gao, Chun-Ling; Wilson, Gregory P.; Luo, Zhe-Xi; Maga, A. Murat; Meng, Qingjin; Wang, Xuri

2010-01-01

374

A surface structural model for ferrihydrite I: Sites related to primary charge, molar mass, and mass density  

NASA Astrophysics Data System (ADS)

A multisite surface complexation (MUSIC) model for ferrihydrite (Fh) has been developed. The surface structure and composition of Fh nanoparticles are described in relation to ion binding and surface charge development. The site densities of the various reactive surface groups, the molar mass, the mass density, the specific surface area, and the particle size are quantified. As derived theoretically, molecular mass and mass density of nanoparticles will depend on the types of surface groups and the corresponding site densities and will vary with particle size and surface area because of a relatively large contribution of the surface groups in comparison to the mineral core of nanoparticles. The nano-sized (˜2.6 nm) particles of freshly prepared 2-line Fh as a whole have an increased molar mass of M ˜ 101 ± 2 g/mol Fe, a reduced mass density of ˜3.5 ± 0.1 g/cm 3, both relatively to the mineral core. The specific surface area is ˜650 m 2/g. Six-line Fh (5-6 nm) has a molar mass of M ˜ 94 ± 2 g/mol, a mass density of ˜3.9 ± 0.1 g/cm 3, and a surface area of ˜280 ± 30 m 2/g. Data analysis shows that the mineral core of Fh has an average chemical composition very close to FeOOH with M ˜ 89 g/mol. The mineral core has a mass density around ˜4.15 ± 0.1 g/cm 3, which is between that of feroxyhyte, goethite, and lepidocrocite. These results can be used to constrain structural models for Fh. Singly-coordinated surface groups dominate the surface of ferrihydrite (˜6.0 ± 0.5 nm -2). These groups can be present in two structural configurations. In pairs, the groups either form the edge of a single Fe-octahedron (˜2.5 nm -2) or are present at a single corner (˜3.5 nm -2) of two adjacent Fe octahedra. These configurations can form bidentate surface complexes by edge- and double-corner sharing, respectively, and may therefore respond differently to the binding of ions such as uranyl, carbonate, arsenite, phosphate, and others. The relatively low PZC of ferrihydrite can be rationalized based on the estimated proton affinity constant for singly-coordinated surface groups. Nanoparticles have an enhanced surface charge. The charging behavior of Fh nanoparticles can be described satisfactory using the capacitance of a spherical Stern layer condenser in combination with a diffuse double layer for flat plates.

Hiemstra, Tjisse; Van Riemsdijk, Willem H.

2009-08-01

375

Changes of structure and property of alkali soluble hydroxyethyl celluloses (HECs) and their regenerated films with the molar substitution.  

PubMed

Hydroxyethyl celluloses (HECs) with low molar substitutions (MS) were prepared by reaction of alkali cellulose with ethylene oxide (EO) in a heterogeneous process. NMR, FTIR, WAXD, TG, solubility and tensile tests were adopted to investigate the changes of structures and properties of HECs with their MS values. NMR results showed that the hydroxyethyl groups were introduced into the cellulose chains as expected, causing the destruction in ordered structure and a loss in crystallinity. Crystal transformation from cellulose I of raw cellulose to cellulose II of HECs was proved by different methods. The crystalline structure of HEC seriously deteriorated with the rising MS value, accompanying lower thermal stability and improvements on its solubility in 8 wt% NaOH solvent and moisture related properties such as water retention. These different properties depending on the MS values endowed HECs with various potential applications in the form of regenerated cellulose fibers or other absorbent materials. PMID:25263883

Li, Faxue; Wang, Wencong; Wang, Xueli; Yu, Jianyong

2014-12-19

376

Fast Computation of Solvation Free Energies with Molecular Density Functional Theory: Thermodynamic-Ensemble Partial Molar Volume Corrections  

E-print Network

Molecular Density Functional Theory (MDFT) offers an efficient implicit- solvent method to estimate molecule solvation free-energies whereas conserving a fully molecular representation of the solvent. Even within a second order ap- proximation for the free-energy functional, the so-called homogeneous reference uid approximation, we show that the hydration free-energies computed for a dataset of 500 organic compounds are of similar quality as those obtained from molecular dynamics free-energy perturbation simulations, with a computer cost reduced by two to three orders of magnitude. This requires to introduce the proper partial volume correction to transform the results from the grand canoni- cal to the isobaric-isotherm ensemble that is pertinent to experiments. We show that this correction can be extended to 3D-RISM calculations, giving a sound theoretical justifcation to empirical partial molar volume corrections that have been proposed recently.

Volodymyr P. Sergiievskyi; Guillaume Jeanmairet; Maximilien Levesque; Daniel Borgis

2014-06-11

377

Studies on the molar conductivity behavior of PMMA-co-MA electrolyte solution at different polymer concentrations  

NASA Astrophysics Data System (ADS)

Polymer is an important constituent of liquid polymer electrolyte along with salt and solvent. The limiting molar conductivity (?0) and equilibrium constant (Keq) for LiClO4 in PMMA-co-MA solution was studied at 25.0 °C. Both ?0 and Keq were determined after Oswald's dilution law for a range of PMMA-co-MA concentrations (0.0010 - 0.0030 g cm-3). It was noticed that, as PMMA-co-MA concentration increased the ?0 value showed a decreasing trend. However, this decreasing trend did not cause any significant improvement in total LiClO4 dissociation for the electrolyte. This is supported by almost constant Keq values for the range of PMMA-co-MA concentration was at the same order of magnitude. The constant Keq with a decreasing ?0 might due to the formation of ions aggregation in the electrolyte.

Hanibah, Hussein; Ahmad, Azizan; Hassan, Nur Hasyareeda

2014-09-01

378

Effect of fuel to oxidant molar ratio on particle size and LPG sensing properties of ZnO nanoparticles prepared by simple solution combustion method.  

NASA Astrophysics Data System (ADS)

ZnO nanoparticles of different size were prepared by varying the molar ratio of glycine and zinc nitrate hexahydrate as fuel and oxidizer (F/O molar ratio = 0.8, 1.11, 1.7) by simple solution combustion method. Powder samples were characterized by UV-Visible spectrophotometer, X-ray diffractometer (XRD), Scanning electron microscope (SEM). LPG sensing measurements were carried out in the temperature range 523-673K. It was found that, ZnO nanoparticle thick film prepared from F/O molar ratio 1.7 has maximum sensitivity of 5.20% for 520ppm of LPG at 623K compared to other thick films.

Naveen, C. S.; Rajeeva, M. P.; Lamani, Ashok R.; Deshmukh, P. R.; Lokhande, C. D.; Jayanna, H. S.

2013-06-01

379

Rapidly progressing, fatal and acute promyelocytic leukaemia that initially manifested as a painful third molar: a case report  

PubMed Central

Introduction Acute promyelocytic leukaemia, an uncommon and devastating subtype of leukaemia, is highly prevalent in Latin American populations. The disease may be detected by a dentist since oral signs are often the initial manifestation. However, despite several cases describing oral manifestations of acute promyelocytic leukaemia and genetic analysis, reports of acute promyelocytic leukaemia in Hispanic populations are scarce. The identification of third molar pain as an initial clinical manifestation is also uncommon. This is the first known case involving these particular features. Case presentation A 24-year-old Latin American man without relevant antecedents consulted a dentist for pain in his third molar. After two dental extractions, the patient experienced increased pain, poor healing, jaw enlargement and bleeding. A physical examination later revealed that the patient had pallor, jaw enlargement, ecchymoses and gingival haemorrhage. Laboratory findings showed pancytopaenia, delayed coagulation times, hypoalbuminaemia and elevated lactate dehydrogenase. Splenomegaly was detected on ultrasonography. Peripheral blood and bone marrow analyses revealed a hypercellular infiltrate of atypical promyelocytic cells. Cytogenetic analysis showing genetic translocation t(15;17) further confirmed acute promyelocytic leukaemia. Despite early chemotherapy, the patient died within one week due to intracranial bleeding secondary to disseminated intravascular coagulation. Conclusion The description of this unusual presentation of acute promyelocytic leukaemia, the diagnostic difficulties and the fatal outcome are particularly directed toward dental surgery practitioners to emphasise the importance of clinical assessment and preoperative evaluation as a minimal clinically-oriented routine. This case may also be of particular interest to haematologists, since the patient's cytogenetic analysis, clinical course and therapeutic response are well documented. PMID:19946580

2009-01-01

380

Quantitative pixel grey measurement of the "high-risk" sign, darkening of third molar roots: a pilot study  

PubMed Central

Objectives: Our aim was to examine the panoramic darkening of the root, which is a “high-risk” sign, using quantitative measurements of pixel grey values to determine different aetiological backgrounds, namely inferior alveolar nerve (IAN) exposure with or without groove formation of the third molar roots or thinning/fenestration of the lingual cortex (LCTF). Methods: 38 impacted third molars that had been surgically removed and had darkened roots on panoramic radiographs were included in this retrospective case–control study. 15 IAN exposure cases were selected for the case group, and 23 cases with proven lingual cortical thinning or fenestration were chosen for the control group. The mean pixel grey values of selected areas in the dark band (D) and control areas within the same roots (R) were determined with the ImageTool (University of Texas Health Science Center, San Antonio, TX) software. The differences in pixel values (R–D) of the IAN and LCTF groups were analysed using the Mann–Whitney U-test and Pearson's ?2 test. Results: The medians of the R–D pixel values were 45.7 in the IAN group and 34.3 in the LCTF group, whereas the interquartile ranges were 12.0 (IAN) and 18.3 (LCTF) (p < 0.001). The R–D critical value at which the outcomes differed significantly was 38. If the differences in pixel grey values (R–D) were higher than 38, the chance of IAN exposure was approximately 32 times higher than the chance of LCTF (?2 test, p < 0.001; odds ratio, 32.0; 95% confidence interval, 3.5–293.1). Conclusions: The pre-operative prediction of IAN exposure or lingual cortical thinning in cases with “darkening” is possible based on pixel grey measurements of digital panoramic radiographs. PMID:23775927

Szalma, J; Bata, Z; Lempel, E; Jeges, S; Olasz, L

2013-01-01

381

Kinetics of the Free-Radical Polymerization of Isobornyl Methacrylate in the Presence of Polyisobutylenes of Different Molar Masses  

E-print Network

The effect of a linear polymer dissolved in a reactive monomer on the kinetics of free-radical polymerization is studied. The selected system was a solution of polyisobutylene (PIB) in isobornyl methacrylate (IBoMA). Ternary phase diagrams of PIB, IBoMA and poly(isobornyl methacrylate) (PIBoMA) were built at 80C. They were shifted to lower conversions when increasing the molar mass of PIB. Different PIBs exhibiting CPC at advanced conversions were selected for the kinetic study performed employing differential scanning calorimetry (DSC) at 80C. A simple kinetic model for free-radical polymerizations describing the relevant termination rate constant in terms of the free-volume theory, provided a consistent fitting of the polymerization rates in the conversion range where the solution remained homogeneous. Increasing the molar mass of PIB led to an increase in polymerization rate due to the decrease in free volume and the corresponding decrease of the termination rate. Increasing the amount of a particular PIB in the initial formulation led to a less marked gel effect, explained by the smaller relative variation of free volume with conversion. The dimensionless free volume of PIB obtained from the kinetic model was found to increase with the volume concentration of chain ends, as expected. Under conditions where phase separation took place at very low conversions, the overall polymerization rate exhibited the presence of two maxima (gel effects), representing the polymerization in two different phases. The first maximum was associated to the polymerization taking place in the phase lean in PIB and the second maximum was associated to the polymerization of the monomer that was initially fractionated with PIB.

Ezequiel R. Soule; Julio Borrajo; Roberto J. J. Williams

2013-11-21

382

Pre- and Postnatal Determinants of Deciduous Molar Hypomineralisation in 6-Year-Old Children. The Generation R Study  

PubMed Central

Background Deciduous Molar Hypomineralisation (DMH) and Molar Incisor Hypomineralisation (MIH) are common developmental disturbances in pediatric dentistry. Their occurrence is related. The same determinants as suggested for MIH are expected for DMH, though somewhat earlier in life. Perinatal medical problems may influence the prevalence of DMH but this has not been studied sufficiently. Objective This study aimed to identify possible determinants of DMH in a prospective cohort study among 6-year-old children. Study Design This study was embedded in the Generation R Study, a population-based prospective cohort study from fetal life until young adulthood. The the data were used to identify the determinants of DMH. Clinical photographs of clean, moist teeth were taken with an intra-oral camera in 6690 children (mean age 6.2 years; 49.9% girls). Data on possible determinants that had occurred during pregnancy and/or the child's first year of life were on the basis of manual standardized measurements (like length and weight) and questionnaires. Multivariate analyse with backward and forward selection was performed. Results A number of factors in the pre-, peri- and postnatal phase were found to be associated with DMH. After multivariate logistic regression analyses, Dutch ethnic background, low birth weight, maternal alcohol consumption during pregnancy, and fever episodes in the first year of the child's life were found to play a role in the development of DMH in 6-year-old children. Conclusion This study shows that Dutch ethnicity, low birth weight, alcohol consumption by the mother during pregnancy and any fever in the first year of the child's life are associated with DMH. Not only childhood factors but also prenatal lifestyle factors need to be taken into account when studying determinants for DMH. PMID:24988443

Elfrink, Marlies E. C.; Moll, Henriette A.; Kiefte-de Jong, Jessica C.; Jaddoe, Vincent W. V.; Hofman, Albert; ten Cate, Jacob M.; Veerkamp, Jaap S. J.

2014-01-01

383

Densities, molar volumes, cubic expansion coefficients, and isothermal compressibilities of 1-alkanols from 323. 15 K to 373. 15 K and pressures up to 10 MPa  

SciTech Connect

Densities of six alcohols, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, and 1-dodecanol, in the liquid state have been measured with a vibrating-tube densimeter from 323.15 to 373.15 K at pressures up to 10 MPa. Molar volumes (derived from the densities) have been fitted to polynomials as a function of temperature and pressure. Cubic expansion coefficients and isothermal compressibilities have been derived from molar volumes as a function of temperature and pressure. The results have also been compared with the available literature values.

Garg, S.K.; Banipal, T.S.; Ahluwalia, J.C. (Indian Inst. of Tech., New Delhi (India))

1993-04-01

384

Molecular analysis of 16S rRNA genes identifies potentially periodontopathogenic bacteria and archaea in the plaque of partially-erupted third molars  

Microsoft Academic Search

PurposeSmall subunit rRNA sequencing and phylogenetic analysis were used to identify cultivable and uncultivable micro-organisms present in dental plaque of symptomatic and asymptomatic partially-erupted third molars to determine the prevalence of putative periodontopathogens in pericoronal sites.

J. M. Mansfield; J. H. Campbell; A. R. Bhandari; A. M. Jesionowski; M. M. Vickerman

385

Near-Infrared (NIR) Study of Hydrogen Bonding of Methanol Molecules in Polar and Nonpolar Solvents: An Approach from Concentration-Dependent Molar Absorptivity.  

PubMed

Differences in the hydrogen-bonding states of methanol in polar and nonpolar solvents were studied by using the first overtone of O-H stretching vibrations observed in the near-infrared (NIR) band ranging from 7500 to 6000 cm(-1). To eliminate the absorption of solvents, NIR-inactive nonpolar solvents carbon tetrachloride (CCl4) and tetrachloroethylene (C2Cl4) were chosen, along with deuterium-substituted polar solvents acetone-d6, acetonitrile-d3, 1,4-dioxane-d8, and tetrahydrofuran (THF)-d8. The changes in the hydrogen-bonding states of methanol during mixing with the solvents were estimated using the extended molar absorption spectrum, which was defined as the concentration difference. The extended molar absorption spectra in different concentrations were decomposed into a finite number of independent factors using a multivariate curve resolution-alternating least squares calculation. Two and three such factors were sufficient to reproduce the extended molar absorption spectra for the nonpolar and polar solvents, respectively. The detailed assignments of each factor were estimated using the calculated loadings and scores. A similarity analysis was also applied to the extended molar absorption spectra of methanol and effectively quantified the deviation from the spectrum of pure methanol. The methanol and solvent affinities were also compared. PMID:25198653

Mikami, Yuho; Ikehata, Akifumi; Hashimoto, Chihiro; Ozaki, Yukihiro

2014-10-01

386

Antibiotic prophylaxis in third molar surgery: A randomized double-blind placebo-controlled clinical trial using split-mouth technique.  

PubMed

The use of prophylactic antibiotics to reduce postoperative complications in third molar surgery remains controversial. The study was a prospective, randomized, double blind, placebo-controlled clinical trial. 100 patients were randomly assigned to two groups. Each patient acted as their own control using the split-mouth technique. Two unilateral impacted third molars were removed under antibiotic cover and the other two were removed without antibiotic cover. The first group received antibiotics on the first surgical visit. On the second surgical visit (after 3 weeks), placebo capsules were given or vice versa. The second group received antibiotics with continued therapy for 2 days on the first surgical visit and on the second surgical visit (after 3 weeks) placebo capsules were given or vice versa. Pain, swelling, infection, trismus and temperature were recorded on days 3, 7 and 14 after surgery. Of 380 impactions, 6 sockets (2%) became infected. There was no statistically significant difference in the infection rate, pain, swelling, trismus, and temperature between the two groups (p>0.05). Results of the study showed that prophylactic antibiotics did not have a statistically significant effect on postoperative infections in third molar surgery and should not be routinely administered when third molars are removed in non-immunocompromised patients. PMID:20117915

Siddiqi, A; Morkel, J A; Zafar, S

2010-02-01

387

Molar Absorptivity and Quantum Yield of Fe(II) Photo-formation for the Aqueous Solutions of Fe(III)-Dicarboxylate Comlexes  

NASA Astrophysics Data System (ADS)

Fe(III)/Fe(II) cycle in the environment affects formation of active oxygen species such as hydrogen peroxide and hydroxyl radicals, which in turn determines lifetimes of many organic compounds. Although aqueous Fe(III)-dicarboxylate complexes are considered to be an important source of photo-chemically formed Fe(II), molar absorptivity and quantum yield of Fe(II) formation for individual species are not well understood. The Visual MINTEQ computer program was used to calculate the equilibrium concentrations of individual Fe(III)-dicarboxylate species in the aqueous solutions of Fe(III)-dicarboxylate complexes. The molar absorptivity and the product of the quantum yield and the molar absorptivity of Fe(III)-dicarboxylate species were obtained by UV-VIS spectrophotometer and photochemical experiments, and these experimental data were combined with the calculated equilibrium Fe(III)-dicarboxylate concentrations to determine individual molar absorptivity and quantum yield of Fe(II) photo-formation for a specific Fe(III)-dicarboxylate species. Dicarboxylate compounds studied were oxalate, malonate, succinate, malate, and phthalate.

Hitomi, Y.; Arakaki, T.

2009-04-01

388

Mass action model for solute distribution between water and micelles. Partial molar volumes of butanol and pentanol in dodecyl surfactant solutions  

Microsoft Academic Search

The densities of 1-butanol and 1-pentanol were measured in aqueous solutions of dodecyltrimethylammonium bromide and dodecyldimethylamine oxide and the partial molar volumes at infinite dilution of the alcohols in aqueous surfactants solutions were obtained. The observed trends of this quantity as a function of the surfactant concentration were rationalized using a mass-action model for the alcohol distribution between the aqueous

R. De Lisi; V. Turco Liveri; M. Castagnolo; A. Inglese

1986-01-01

389

Effectiveness of 1% versus 0.2% chlorhexidine gels in reducing alveolar osteitis from mandibular third molar surgery: A randomized, double-blind clinical trial  

PubMed Central

Purpose: Alveolar osteitis (AO) is the most common postoperative complication of dental extractions. The purpose of this study was to compare the effectiveness of 1% versus 0.2% chlorhexidine (CHX) gel in reducing postoperative AO after surgical extraction of mandibular third molars, and assess the impact of treatment on the Oral HealthRelated Quality of Life (OHRQoL). Material and Methods: This clinical study was a randomized, double-blind clinical trial. Eighty eight patients underwent surgical extraction of one retained mandibular third molar with the intra-alveolar application of 0.2% CHX gel. Afterwards, they were assigned to one of two groups: 1% CHX gel (n=42) or 0.2% CHX gel (n=46). The patients applied the gel twice a day to the wound for one week. All patients were evaluated for AO. Results: In the 0.2% CHX gel group, 13% of AO incidence was found, while in the 1% CHX gel group, AO incidence was 7%, a difference that was not statistically significant. Variables such as sensation of pain and inflammation at baseline and during one week, as well as OHRQoL of the patients at 24 hours and 7 days post-extraction, gave no statistically significant differences. Conclusions: There are no significant differences in AO after surgical extraction of mandibular third molars, when comparing applying 1% CHX gel twice a day for 7 days with 0.2% CHX gel. Key words:Alveolar osteitis, chlorhexidine gel, third molar. PMID:23722126

Bravo-Perez, Manuel; Sanchez-Lopez, Jose D.; Munoz-Soto, Esther; Romero-Olid, Maria N.; Baca-Garcia, Pilar

2013-01-01

390

Relationships between the evolution of the percentage in weight of polar compounds and that of the molar percentage of acyl groups of edible oils submitted to frying temperature.  

PubMed

The evolution of the molar percentage of several kinds of acyl groups of extra virgin olive, sunflower and virgin linseed oils was monitored throughout heating at frying temperature by means of (1)H nuclear magnetic resonance. Likewise, the evolution of the percentage in weight of the polar compounds of the same oils under the same heating conditions was also determined. Relationships between both sets of parameters, in each oil and in the oils as a group, were studied. An equation which is able to accurately predict the percentage in weight of the polar compounds, throughout the heating at frying temperature, of any one of these three oils, from the molar percentage of triunsaturated, diunsaturated and monounsaturated acyl groups, was obtained. In this way both molar percentage of acyl groups and percentage in weight of polar compounds can be obtained in a few minutes that registration of the (1)H NMR spectrum of the oil takes, in addition to the rest of information provided by this technique. The study reveals the close relationships between percentage in weight of polar compounds and the composition expressed in terms of molar percentages of acyl groups in edible oils heated at frying temperature. PMID:23411253

Guillén, Maria D; Uriarte, Patricia S

2013-06-01

391

The reliability of values of molar mass, the factor that relates measurements expressed in two SI base units (mass and amount of substance)  

Microsoft Academic Search

Progress in science is often achieved by modifications of hypotheses imposed by reliable results of measurements with small uncertainty. The application of the discipline of metrology to chemistry, based on the SI and the estimation of uncertainties, is illustrated by suggested refinements of the presentation of molar-mass values of the elements as recommended, and biennially revised, by the International Union

P De Bièvre; H S Peiser

1997-01-01

392

The effect of Cu/Zn molar ratio on CO2 hydrogenation over Cu/ZnO/ZrO2/Al2O3 catalyst  

NASA Astrophysics Data System (ADS)

Catalytic hydrogenation of carbon dioxide (CO2) to methanol is an attractive way to recycle and utilize CO2. A series of Cu / ZnO / Al2O3/ZrO2 catalysts (CZAZ) containing different molar ratios of Cu/Zn were prepared by the co-precipitation method and investigated in a stirred slurry autoclave system. The catalysts were characterized by temperature-programmed reduction (TPR), field emission scanning electron microscopy-energy dispersive analysis (FESEM-EDX), X-ray diffraction (XRD) and N2 adsorption-desorption. Higher surface area, SABET values (42.6-59.9 m2/g) are recorded at low (1) and high (5) Cu/Zn ratios with the minimum value of 35.71 m2/g found for a Cu/Zn of 3. The reducibility of the metal oxides formed after calcination of catalyst samples was also affected due to change in metal-support interaction. At a low reaction temperature of 443 K, total gas pressure of 3.0 MPa and 0.1 g/mL of the CZAZ catalyst, the selectivity to methanol decreased as the Cu/Zn molar ratio increased, and the maximum selectivity of 67.73 was achieved at Cu/Zn molar ratio of 1. With a reaction time of 3h, the best performing catalyst was CZAZ75 with Cu/Zn molar ratio of 5 giving methanol yield of 79.30%.

Shaharun, Salina; Shaharun, Maizatul S.; Mohamad, Dasmawati; Taha, Mohd F.

2014-10-01

393

Micro-computed tomography analysis of changes in the periodontal ligament and alveolar bone proper induced by occlusal hypofunction of rat molars  

PubMed Central

Objective To three-dimensionally elucidate the effects of occlusal hypofunction on the periodontal ligament and alveolar bone proper of rat molars by micro-computed tomography (micro-CT). Methods Occlusal function in the molar area was restricted by attaching an anterior bite plate on the maxillary incisors and a metal cap on the mandibular incisors of 5-week-old male Wistar rats for 1 week. The periodontal ligament space and alveolar bone proper around roots of the mandibular first molar were assessed by histology and micro-CT. Results The periodontal ligament space was narrower and the alveolar bone proper was sparser and less continuous in the hypofunction group than in the control group. Further, both the volume of the periodontal ligament and the volumetric ratio of the alveolar bone proper to the total tissue in the region of interest were significantly lower in the hypofunction group (p < 0.05). Conclusions Occlusal hypofunction induces atrophic changes in the periodontal ligament and alveolar bone proper of rat molars.

Hosomichi, Jun; Nakamura, Saeko; Ono, Takashi

2014-01-01

394

Palatal anaesthesia for the removal of maxillary third molars as practised by oral and maxillofacial surgeons in Australia and New Zealand  

Microsoft Academic Search

Background: Injections of local anaesthetic to the palate are well known to be poorly tolerated. The absolute requirement of a palatal injection for the removal of maxillary third molars has never been investigated. The aim of this study was to document the current practice of palatal anaesthesia for extraction of these teeth with local anaesthesia as practised by oral and

ME Badcock; MJ McCullough

2007-01-01

395

Thin Films Derived by a Particulate Sol-Gel Route with Various Cr:Ti Molar Ratios  

NASA Astrophysics Data System (ADS)

Nanocrystalline and nanostructured TiO2-Cr2O3 thin films and powders were prepared by a facile and straightforward aqueous particulate sol-gel route at low temperature of 400°C. The prepared sols showed a narrow particle size distribution with hydrodynamic diameter in the range of 17.7 nm to 19.0 nm. Moreover, the sols were stable over 4 months, with constant zeta potential measured during this period. The effect of the Cr:Ti molar ratio on the crystallization behavior of the products was studied. X-ray diffraction (XRD) analysis revealed that the powders crystallized at low temperature of 400°C, containing anatase-TiO2, rutile-TiO2, and Cr2O3 phases, depending on the annealing temperature and Cr:Ti molar ratio. Furthermore, it was found that Cr2O3 retarded the anatase to rutile transformation up to 800°C. The activation energy of crystallite growth was calculated to be in the range of 1.3 kJ/mol to 2.9 kJ/mol. Transmission electron microscopy (TEM) imaging showed that one of the smallest crystallite sizes was obtained for TiO2-Cr2O3 binary mixed oxide, being 5 nm at 500°C. Field-emission scanning electron microscopy (FESEM) analysis revealed that the deposited thin films had nanostructured morphology with average grain size in the range of 20 nm to 40 nm at 500°C. Thin films produced under optimized conditions showed excellent microstructural properties for gas sensing applications. They exhibited a remarkable response towards low concentrations of NO2 gas at low operating temperature of 200°C, resulting in increased thermal stability of sensing films as well as a decrease in their power consumption. Furthermore, calibration curves revealed that TiO2-Cr2O3 sensors followed the power law (where S is the sensor response, the coefficients A and B are constants, and [gas] is the gas concentration) for two types of gas, exhibiting excellent capability for detection of low gas concentrations.

Mohammadi, M. R.; Fray, D. J.

2014-11-01

396

Spectrum of excess partial molar absorptivity. Part II: a near infrared spectroscopic study of aqueous Na-halides.  

PubMed

Our earlier thermodynamic studies suggested that F(-) and Cl(-) form hydration shells with the hydration number 14 ± 2 and 2.3 ± 0.6, respectively, and leave the bulk H(2)O away from hydration shells unperturbed. Br(-) and I(-), on the other hand, form hydrogen bonds directly with the momentarily existing hydrogen bond network of H(2)O, and retard the degree of entropy-volume cross fluctuation inherent in liquid H(2)O. The effect of the latter is stronger for I(-) than Br(-). Here we seek additional information about this qualitative difference between Cl(-) and (Br(-) and I(-)) pair by near infrared (NIR) spectroscopy. We analyze the ?(2) + ?(3) band of H(2)O in the range 4600-5500 cm(-1) of aqueous solutions of NaCl, NaBr and NaI, by a new approach. From observed absorbance, we calculate excess molar absorptivity, ?(E), excess over the additive contributions of solute and solvent. ?(E) thus contains information about the effect of inter-molecular interactions in the ?(2) + ?(3) spectrum. The spectrum of ?(E) shows three bands; two negative ones at 5263 and 4873 cm(-1), and the positive band at 5123 cm(-1). We then define and calculate the excess partial molar absorptivity of each salt, ?(E)(salt). From the behaviour of ?(E)(salt) we suggest that the negative band at 5263 cm(-1) represents free H(2)O without much hydrogen bonding under the influence of local electric field of ions. Furthermore, from a sudden change in the x(salt) (mole fraction of salt) dependence of ?(E)(salt), we suggest that there is an ion-pairing in x(salt) > 0.032, 0.036, and 0.04 for NaCl, NaBr and NaI respectively. The positive band of ?(E) at 5123 cm(-1) is attributed to a modestly organized hydrogen bond network of H(2)O (or liquid-likeness), and the x(salt) dependence of ? indicated a qualitative difference in the effect of Cl(-) from those of Br(-) and I(-). Namely, the values of ?(E)(salt) stay constant for Cl(-) but those for Br(-) and I(-) decrease smoothly on increasing the salt mole fraction. The mole fraction dependence of ?(E)(salt) at the 4873 cm(-1) band, due to ice-likeness in H(2)O, shows a subtle difference between Cl(-) and (Br(-), I(-)) pair. PMID:22358251

Sebe, Fumie; Nishikawa, Keiko; Koga, Yoshikata

2012-04-01

397

Challenges in analysis of high-molar mass dextrans: comparison of HPSEC, AsFlFFF and DOSY NMR spectroscopy.  

PubMed

Dilute solutions of various dextran standards, a high-molar mass (HMM) commercial dextran from Leuconostoc spp., and HMM dextrans isolated from Weissella confusa and Leuconostoc citreum were analyzed with high-performance size-exclusion chromatography (HPSEC), asymmetric flow field-flow fractionation (AsFlFFF), and diffusion-ordered NMR spectroscopy (DOSY). HPSEC analyses were performed in aqueous and dimethyl sulfoxide (DMSO) solutions, while only aqueous solutions were utilized in AsFlFFF and DOSY. The study showed that all methods were applicable to dextran analysis, but differences between the aqueous and DMSO-based solutions were obtained for HMM samples. These differences were attributed to the presence of aggregates in aqueous solution that were less prevalent in DMSO. The study showed that DOSY provides an estimate of the size of HMM dextrans, though calibration standards may be required for each experimental set-up. To our knowledge, this is the first study utilizing these three methods in analyzing HMM dextrans. PMID:24274497

Maina, Ndegwa Henry; Pitkänen, Leena; Heikkinen, Sami; Tuomainen, Päivi; Virkki, Liisa; Tenkanen, Maija

2014-01-01

398

Lower third molar infection with purulent discharge through the external auditory meatus. Case report and review of literature.  

PubMed

This manuscript reports an uncommon case of inferior third molar facial abscess with purulent secretion drainage through the left external acoustic meatus. The patient's left external acoustic meatus was filled with a purulent secretion observed on a CT scan. He underwent surgery to drain the facial abscess. Despite facial abscesses being routine occurrences, the literature does not contain many case reports of odontogenic facial abscesses with drainage via the external acoustic meatus. These situations occur in two possible ways: multiple fissures in the anterior wall of the cartilaginous portion of the external acoustic meatus; and congenital defects that are occasionally present in the anterior-superior aspect of the external acoustic meatus, known as the foramen of Huschke, which allow communication between the external acoustic meatus and mandibular fossa. These defects may also predispose the patient to the spread of the infection or tumour from the external auditory canal to the infratemporal fossa and vice versa. No otological sequelae were observed in this case. The authors conclude that the hypothesis of bone malformation cannot be excluded, and affirm that any facial abscess requires appropriate and immediate treatment for adequate resolution, by removing the causal factor and providing systemic support. PMID:22004947

Pepato, A O; Yamaji, M A K; Sverzut, C E; Trivellato, A E

2012-03-01

399

Distribution of soil arsenic species, lead and arsenic bound to humic acid molar mass fractions in a contaminated apple orchard.  

PubMed

Excessive application of lead arsenate pesticides in apple orchards during the early 1900s has led to the accumulation of lead and arsenic in these soils. Lead and arsenic bound to soil humic acids (HA) and soil arsenic species in a western Massachusetts apple orchard was investigated. The metal-humate binding profiles of Pb and As were analyzed with size exclusion chromatography-inductively coupled plasma mass spectrometry (SEC-ICP-MS). It was observed that both Pb and As bind "tightly" to soil HA molar mass fractions. The surface soils of the apple orchard contained a ratio of about 14:1 of water soluble As (V) to As (III), while mono-methyl (MMA) and di-methyl arsenic (DMA) were not detectable. The control soil contained comparatively very low levels of As (III) and As (V). The analysis of soil core samples demonstrated that As (III) and As (V) species are confined to the top 20 cm of the soil. PMID:16480799

Newton, Kimberly; Amarasiriwardena, Dulasiri; Xing, Baoshan

2006-09-01

400

Differential expression of E-cadherin, ?-catenin, and Lewis x between invasive hydatidiform moles and post-molar choriocarcinomas.  

PubMed

Trophoblast cell adhesion and migration are carefully coordinated during normal placental development. We have compared the expression of three adhesion molecules, E-cadherin, ?-catenin, and Lewis x, by immunohistochemistry during normal trophoblast differentiation, and in hydatidiform moles and choriocarcinomas. Both E-cadherin and ?-catenin were expressed in normal placenta cytotrophoblast, and this expression decreased with trophoblast maturation. E-cadherin was mainly localized along the contact between cytotrophoblast and syncytiotrophoblast, which indicates its role in the differentiation of the syncytial layer. Lewis x disappeared progressively during differentiation of normal villous vessels, and was expressed in molar pregnancies. Interestingly, whereas choriocarcinomas were not, or poorly, stained, invasive hydatidiform moles (invHMs) strongly expressed Lewis x in vascular structures. This observation correlated well with E-cadherin and ?-catenin expression and suggests that these three markers are associated with the invasive transformation. The presence of robust endothelial structures in invHMs could also explain their ability to maintain organized villous architecture (contrary to metastatic choriocarcinomas) during their invasion of extrauterine tissues such as the lung or the brain after dissemination through the blood flow. In our hands, Lewis x appeared to be a new, reliable marker that can be used to clearly distinguish invHMs from choriocarcinomas. PMID:23681114

Candelier, Jean-Jacques; Frappart, Lucien; Diatta, Ange Lucien; Yadaden, Tarik; Cissé, Mamadou-Lamine; Afoutou, Jean-Marie; Picard, Jean-Yves; Mennesson, Benoît; Slim, Rima; Si-Tayeb, Karim; Coullin, Philippe

2013-06-01

401

Quantifying the effect of milli-molar glucose concentration on thickness of rabbit cornea with optical coherence tomography  

NASA Astrophysics Data System (ADS)

The cornea contributes about 65% of the eye's ability to refract light. Thus, any fluctuation in corneal thickness can cause noticeable changes in vision. The presence of glucose molecules induces a driving force for water to leave the collagen fibrils in the cornea due to the concentration gradient created, thus changing its thickness. In this study, the effect of various milli-molar glucose concentrations on corneal thickness was explored using Optical Coherence Tomography. Whole rabbit eyes were placed in a specially designed dish while immersed in saline to ensure proper hydration of the eye. The cornea was imaged for 10 minutes. In 30 minute increments, a higher concentration of glucose was added, bringing the overall glucose concentration to 10, 15, 20, 25, and 30 mM. The thickness of the cornea was measured every 2 minutes. Ultimately, an inverse relationship was observed, indicating that the increase in glucose concentration yielded a decrease in the corneal thickness. From three separate experiments, the cornea experienced 8 +/- 1, 27 +/- 1, 44 +/- 3, 58 +/- 3, and 64 +/- 3 ?m decrease in thickness from its starting value while exposed to 10, 15, 20, 25, and 30 mM solutions of glucose, respectively. This relationship provides insight on the physiological changes of the cornea as a result of different glucose concentrations. This could potentially be useful in monitoring blood-glucose levels through the eye.

Ghosn, Mohamad G.; Leba, Michael; Vijayananda, Astha; Ansari, Rafat R.; Larin, Kirill V.

2009-02-01

402

The Effect of Zinc to Aluminium Molar Ratio on the Formation of ZINC-ALUMINIUM-4-CHLOROPHENOXYACETATE Nanocomposite  

NASA Astrophysics Data System (ADS)

Layered organic-inorganic hybrid nanocomposite material containing 4-chlorophenoxy acetate, (4CPA) intercalated into zinc-aluminium-layered double hydroxide (ZAL) was prepared by direct self-assembly method for the formation of Zn-Al-4CPA nanocomposite (ZAC). Various Zn2+ to Al3+ molar ratios, R ranging from 1 to 6 were used in the preparation of the mother liquor with fixed concentration of 4CPA at 0.4 M. The pH of the solution was adjusted to 7.5 by slow addition of 2 M NaOH. Well-ordered nanolayered organic-inorganic hybrid nanocomposites with the expansion of basal spacing from 8.9 Å in the layered double hydroxide to 19.1-21.2 Å in the resulting nanocomposites were obtained. The FTIR spectra for the nanocomposites showed that the spectrum composed of spectral features of ZAL and 4CPA showing the successful intercalation of the organic moiety into the LDH interlayer. The BET surface area decreased as the XAl value increased while the percentage loading of 4CPA in the nanocomposites increased in the range of 38.9-44.7 % (w/w) as the XAl increased. This shows that the mole ratio of Zn2+ to Al3+, R in the mother liquor controlled the physicochemical properties of the resulting nanocomposite, Zn-Al-4CPA.

Sarijo, Siti Halimah; Hussein, Mohd. Zobir; Zainal, Zulkarnain; Yahaya, Asmah Hj.

2009-06-01

403

Molar absorptivities of 2,4-D, cymoxanil, fenpropidin, isoproturon and pyrimethanil in aqueous solution in the near-UV  

NASA Astrophysics Data System (ADS)

The absorption spectra of five pesticides, namely 2,4-dichloro-phenoxy acetic acid (2,4-D), cymoxanil, fenpropidin, isoproturon and pyrimethanil, have been measured in aqueous solution using a set-up consisting of two parallel absorption cells coupled to a CCD detector. The absolute values of their molar absorptivity coefficients ? were determined in the wavelength-range 240-344 nm with a deuterium-lamp at room temperature (298 ± 2 K). Using the Beer-Lambert law, values of ? were also determined at 253.7 nm with a Hg-Lamp: ? = 145 ± 14 for 2,4-D, ? = 7940 ± 920 for cymoxanil, ? = 196 ± 14 for fenpropidin, ? = 7330 ± 880 for isoproturon, ? = 13200 ± 1400 for pyrimethanil (in units of M -1 cm -1). The quoted errors correspond to 2 ? obtained from the least square fit analysis and the estimated systematic error of 5% due to the uncertainties in aqueous concentrations. For all the studied compounds, the absorbances measured were lower than 2.3 and did not exhibit any deviation from the Beer-Lambert's law. Our experimental data are discussed and compared to UV spectra of similar molecules when such data were available in the literature. Based on their UV spectra and the calculated fractions of these pesticides in the aqueous phase, their direct photolysis under sunlight environment could occur, except may be for fenpropidin, either in water surfaces or in aqueous droplets contained in the atmospheric clouds.

Feigenbrugel, Valérie; Le Calvé, Stéphane; Mirabel, Philippe

2006-01-01

404

Standard partial molar volumes of some aqueous alkanolamines and alkoxyamines at temperatures up to 325 degrees C: functional group additivity in polar organic solutes under hydrothermal conditions.  

PubMed

Apparent molar volumes of dilute aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), N,N-dimethylethanolamine (DMEA), ethylethanolamine (EAE), 2-diethylethanolamine (2-DEEA), and 3-methoxypropylamine (3-MPA) and their salts were measured at temperatures from 150 to 325 degrees C and pressures as high as 15 MPa. The results were corrected for the ionization and used to obtain the standard partial molar volumes, Vo2. A three-parameter equation of state was used to describe the temperature and pressure dependence of the standard partial molar volumes. The fitting parameters were successfully divided into functional group contributions at all temperatures to obtain the standard partial molar volume contributions. Including literature results for alcohols, carboxylic acids, and hydroxycarboxylic acids yielded the standard partial molar volume contributions of the functional groups >CH-, >CH2, -CH3, -OH, -COOH, -O-, -->N, >NH, -NH2, -COO-Na+, -NH3+Cl-, >NH2+Cl-, and -->NH+Cl- over the range (150 degrees C molar volume of aqueous organic solutes composed of these groups at temperatures up to approximately 310 degrees C and pressures of 10-20 MPa to within a precision of +/-5 cm3 x mol(-1). The model could not be extended to higher temperatures because of uncertainties caused by thermal decomposition. At temperatures above approximately 250 degrees C, the order of the group contributions to Vo2 changes from that observed at 25 degrees C, to become increasingly consistent with the polarity of each functional group. The effect of the dipole moment of each molecule on the contribution to Vo2 from long-range solvent polarization was calculated from the multipole expansion of the Born equation using dipole moments estimated from restricted Hartree-Fock calculations with Gaussian 03 (Gaussian, Inc., Wallingford, CT) and the Onsager reaction-field approximation for solvent effects. Below 325 degrees C, the dipole contribution was found to be less than 2 cm3 x mol(-1) for all the solute molecules studied. At higher temperatures and pressures near steam saturation, the effect is much larger and may explain anomalies in functional group additivity observed in small, very polar solutes. PMID:18412415

Bulemela, E; Tremaine, Peter R

2008-05-01

405

A macroscopic model that connects the molar excess entropy of a deeply supercooled liquid near its glass transition temperature to its viscosity  

E-print Network

For a deeply supercooled liquid near its glass transition temperature, we suggest a possible way to connect the temperature dependence of its molar excess entropy to that of its viscosity by constructing a macroscopic model, where the deeply supercooled liquid is assumed to be a mixture of solid-like and liquid-like micro regions. In this model, we assume that the mole fraction x of the liquid-like micro regions tends to zero as the temperature T of the liquid is decreased and extrapolated to a temperature Tg*, which we assume to be below but close to the lowest glass transition temperature Tg attainable with the slowest possible cooling rate for the liquid. Without referring to any specific microscopic nature of the solid-like and liquid-like micro regions, we also assume that near Tg, the molar enthalpy of the solid-like micro regions is lower than that of the liquid-like micro regions. We then show that the temperature dependence of x is directly related to that of the molar excess entropy. Close to Tg, we assume that an activated motion of the solid-like micro regions controls the viscosity and that this activated motion is a collective motion involving practically all of the solid-like micro-regions so that the molar activation free energy for the activated motion is proportional to the mole fraction, 1-x, of the solid-like micro regions. The temperature dependence of the viscosity is thus connected to that of the molar excess entropy through the temperature dependence of the mole fraction x. As an example, we apply our model to a class of glass formers for which the molar excess entropy at temperatures near Tg is proportional to 1-T/TK with TK < Tg \\sim Tg* and find their viscosities to be well approximated by the Vogel-Fulcher-Tamman equation for temperatures very close to Tg. We estimate the values of three parameters in our model for three glass formers in this class.

Hiroshi Matsuoka

2012-02-04

406

Fatty Acid and Lipid Biosynthetic Genes Are Expressed at Constant Molar Ratios But Different Absolute Levels during Embryogenesis1  

PubMed Central

In plants, fatty acid and complex lipid synthesis requires the correct spatial and temporal activity of many gene products. Quantitative northern analysis showed that mRNA for the biotin carboxylase subunit of heteromeric acetyl-coenzyme A carboxylase, fatty acid synthase components (3-oxoacyl-acyl carrier protein [ACP] reductase, enoyl-ACP reductase, and acyl-ACP thioesterase), and stearoyl-ACP desaturase accumulate in a coordinate manner during Brassica napus embryogenesis. The mRNAs were present in a constant molar stoichiometric ratio. Transcript abundance of mRNAs for the catalytic proteins was found to be similar, whereas the number of ACP transcripts was approximately 7-fold higher. The peak of mRNA accumulation of all products was between 20 and 29 d after flowering; by 42 d after flowering, the steady-state levels of all transcripts fell to about 5% of their peak levels, which suggests that the mRNAs have similar stability and kinetics of synthesis. Biotin carboxylase was found to accumulate to a maximum of 59 fmol mg?1 total RNA in embryos, which is in general agreement with the value of 170 fmol mg?1 determined for Arabidopsis siliques (J.S. Ke, T.N. Wen, B.J. Nikolau, E.S. Wurtele [2000] Plant Physiol 122: 1057–1071). Embryos accumulated between 3- and 15-fold more transcripts per unit total RNA than young leaf tissue; the lower quantity of leaf 3-oxoacyl-ACP reductase mRNA was confirmed by reverse transcriptase-polymerase chain reaction. This is in conflict with analysis of B. napus transcripts using an Arabidopsis microarray (T. Girke, J. Todd, S. Ruuska, J. White, C. Benning, J. Ohlrogge [2000] Plant Physiol 124: 1570–1581) where similar leaf to seed levels of fatty acid synthase component mRNAs were reported. PMID:12011361

O'Hara, Paul; Slabas, Antoni R.; Fawcett, Tony

2002-01-01

407

Comparison of dental measurement systems for taxonomic assignment of Neanderthal and modern human lower second deciduous molars.  

PubMed

Traditional morphometric approaches for taxonomic assignment of Neanderthal and modern human dental remains are mainly characterized by caliper measurements of tooth crowns. Several studies have recently described differences in dental tissue proportions and enamel thickness between Neanderthal and modern human teeth. At least for the lower second deciduous molar (dm(2)), a three-dimensional lateral relative enamel thickness index has been proposed for separating the two taxa. This index has the advantage over other measurements of being applicable to worn teeth because it ignores the occlusal aspect of the crown. Nevertheless, a comparative evaluation of traditional crown dimensions and lateral dental tissue proportion measurements for taxonomic assignment of Neanderthal and modern human dm(2)s has not yet been performed. In this study, we compare various parameters gathered from the lateral aspects of the crown. These parameters include crown diameters, height of the lateral wall of the crown (lateral crown height = LCH), lateral enamel thickness, and dentine volume of the lateral wall, including the volume of the coronal pulp chamber (lateral dentine plus pulp volume = LDPV), in a 3D digital sample of Neanderthal and modern human dm(2)s to evaluate their utility in separating the two taxa. The LDPV and the LCH allow us to discriminate between Neanderthals and modern humans with 88.5% and 92.3% accuracy, respectively. Though our results confirm that Neanderthal dm(2)s have lower relative enamel thickness (RET) index compared with modern humans (p = 0.005), only 70% of the specimens were correctly classified on the basis of the RET index. We also emphasize that results of the lateral enamel thickness method depend on the magnitude of the interproximal wear. Accordingly, we suggest using the LCH or the LDPV to discriminate between Neanderthal and modern human dm(2)s. These parameters are more independent of interproximal wear and loss of lateral enamel. PMID:21624638

Benazzi, Stefano; Fornai, Cinzia; Bayle, Priscilla; Coquerelle, Michael; Kullmer, Ottmar; Mallegni, Francesco; Weber, Gerhard W

2011-09-01

408

Determination of the Relative Partial Molar Enthalpy of Decyldimethylphospine Oxide in H2O and D2O at 25°C  

PubMed

The relative partial molar enthalpy of decyldimethylphosphine oxide has been determined in H2O and D2O from infinite dilution to about 8 mm at 25°C. The shapes of the resulting curves resemble those previously reported for ionic but not nonionic surfactants and are inconsistent with existing models of micelle formation. The enthalpy of micelle formation (corresponding to the maximum value of the relative partial molar enthalpy of the surfactant) was 12,900 ± 200 cal/mol in H2O and 10,600 ± 200 cal/mol in D2O. The cmc was lower in D2O than in H2O as expected (3.64 versus 4.2 mm). PMID:9073432

Kresheck

1997-03-15

409

Prevalence and Site Characteristics of Dental Caries in Primary Molar Teeth from Prehistoric Times to the 18th Century in England  

Microsoft Academic Search

A total of 1,974 primary molar teeth from the skeletal remains of 373 children from Prehistoric times to the 18th century were examined for caries prevalence and site characteristics. Results showed that caries in primary teeth was initiated more often at the cemento-enamel junction than the contact point in most time periods and that caries prevalence values recorded were comparable

E. A. O’Sullivan; S. A. Williams; R. C. Wakefield; J. E. Cape; M. E. J. Curzon

1993-01-01

410

Densities and excess molar volumes of formic acid, acetic acid and propionic acid in pure water and in water?+?Surf Excel solutions at different temperatures  

Microsoft Academic Search

Densities, ? of the systems formic acid, acetic acid and propionic acid in water and in 0.05% and 0.1% Surf Excel (SE) solutions in water were measured at temperatures 303.15, 308.15, 313.15, 318.15 and 323.15?K respectively covering the whole composition range. Excess molar volumes, for the systems were found to be negative and their values were found to increase with

M. A. Motin; M. H. Kabir; E. M. Huque

2005-01-01

411

An In vitro Comparison of Furcal Perforation Repaired with Pro-root MTA and New Endodontic Cement in Primary Molar Teeth- A Microleakage Study  

PubMed Central

Statement of Problem: One of the most challenging procedural accidents during pulpotomy of primary molars is furcal perforation. To prevent bacterial invasion, the perforation site should be sealed as soon as possible. Purpose: The aim of the current study is to investigate the ability of the pro-root MTA and new endodontic cement (NEC) in repairing the furcation perforations of primary molar teeth. Materials and Method: In this in vitro study, 42 extracted primary molars were selected. Their roots were sectioned horizontally and standard access cavity was prepared. The orifices and the root apices were sealed with two layers of resin composite.The samples were randomly assigned into 2 groups. 6 teeth were considered as the positive and the negative controls. In the experimental groups; perforation was made. In group 1 and 2, perforation site received pro-root MTA and NEC respectively. The teeth were covered by two layers of nail polish except for the external surface of the perforation site. The negative control group received no repairing material. All teeth were mounted and sterilized for 24 hours. Lower chambers were filled with sterilized Muller Hinton broth. Bacterial suspension of Enterococcus faecalis in 0.5 McFarland was prepared. The repaired site was then exposed to the bacterial suspension of Enterococcus faecalis every 3 days. All samples were inserted in an incubator at 37oC and 100% humidity. The turbidity of the samples was detected for a period of 30 days. Data were analyzed by Chi- square test. Results: 44% of samples in Pro- root group, 50% of the samples in the NEC group showed contaminations during 30 days. There was no significant difference between these two groups (p= 0.799). Conclusion: With limitations of this study, Pro- root MTA and NEC showed similar capability in sealing the furcal perforations of the primary molars. PMID:24738087

Haghgoo, R.; Niyakan, M.; Nazari Moghaddam, K.; Asgary, S.; Mostafaloo, N.

2014-01-01

412

Caries-Preventive Effects of Polycarboxylate Cement Containing Na2PO3F Sealed on Occlusal Surfaces in Newly Erupted Permanent Molars  

Microsoft Academic Search

Newly erupted premolars were sealed with MFP cement (15% Na2PO3F) for a week. After extraction, fluoride concentrations in the surface enamel were measured using a fluoride-specific ion electrode. Uptake of the fluoride was noted up to a depth of 20 ?m from the enamel surface. In clinical experiments, 158 pairs of newly erupted sound first permanent molars were used. The

S. Sobue; M. Okamoto; Y. Moriwaki

1981-01-01

413

Partial molar volumes and viscosity B-coefficients of arginine in aqueous glucose, sucrose and l-ascorbic acid solutions at T = 298.15 K  

Microsoft Academic Search

Densities and viscosities of arginine in (glucose+water), (sucrose+water) and (l-ascorbic acid+water) mixed solvents have been measured at T=298.15 K by an oscillating-tube densimeter and viscometer. Standard-state partial molar volume, hydration number and viscosity B-coefficients of arginine have been calculated. The transfer volumes from water to (sugar+water) or (l-ascorbic acid+water) mixed solvents have been obtained and discussed in terms of the

Changwei Zhao; Peisheng Ma; Jiding Li

2005-01-01

414

Age estimation using CT imaging of the third molar tooth, the medial clavicular epiphysis, and the spheno-occipital synchondrosis: A multifactorial approach  

Microsoft Academic Search

A multi-factorial method for estimating age was devised based on the development of the 3rd molar tooth, the medial clavicular epiphysis, and the spheno-occipital synchondrosis, using multiple regression as the means to construct age estimation formulae and CT scanning as the imaging modality. The sample consisted of approximately 600 individuals from a contemporary Australian population, between the ages of 15

Richard B. Bassed; Christopher Briggs; Olaf H. Drummer

2011-01-01

415

Influence of Cd2+/S2- molar ratio and of different capping environments in the optical properties of CdS nanoparticles incorporated within a hybrid diureasil matrix  

NASA Astrophysics Data System (ADS)

The incorporation of CdS nanoparticles (NPs), as prepared through colloidal methods using reverse micelles, within diureasil hybrid organic-inorganic sol-gel matrices was investigated. Several experimental conditions, namely the influence of capping agent 3-mercaptopropyltrimethoxysilane (MPTMS) or the use of tetraethoxysilane (TEOS), were studied in order to assure the preservation of the original optical properties of colloidal CdS NPs after the incorporation of the NPs within the solid diureasil hybrid matrix. The diureasil matrix is based on a siliceous network cross linked through urea bonds to poly(oxyethylene)/poly(oxypropylene) (PEO/PPO) chains. The influence of the Cd2+/S2- molar ratio of the NPs in the stability and dispersion of the NPs within the diureasil matrix was also investigated. The obtained CdS doped hybrid matrix was characterized by absorption, steady-state and time-resolved photoluminescence (PL) spectroscopy and by transmission electron microscopy (TEM). The stability of the CdS NPs within the hybrid matrix showed to be dependent on the Cd2+/S2- molar ratio used in the synthesis of the NPs. The use of MPTMS proved to be crucial in the preservation of the original optical properties of the colloidal CdS NPs after the incorporation of the NPs within the hybrid matrix. The effect of MPTMS was in turn influenced by the Cd2+/S2- molar ratio employed in the synthesis of the CdS NPs. The use of MPTMS was less effective when Cd2+/S2- molar ratio equal to 0.5 was used. In the absence of MPTMS or TEOS larger NPs size distribution and clustering of the CdS NPs were obtained after the transfer of the NPs into the hybrid matrix.

Gonçalves, Luis F. F. F.; Silva, Carlos J. R.; Kanodarwala, Fehmida K.; Stride, John A.; Pereira, Mario R.; Gomes, Maria J. M.

2014-09-01

416

Improved selective cholesterol adsorption by molecularly imprinted poly(methacrylic acid)/silica (PMAA-SiO2) hybrid material synthesized with different molar ratios.  

PubMed

The present paper describes the synthesis of molecularly imprinted polymer - poly(methacrylic acid)/silica and reports its performance feasibility with desired ads