89 results match your criteria mesial cusps

Influence of cavity depth and restoration of non-carious cervical root lesions on strain distribution from various loading sites.

BMC Oral Health 2020 04 7;20(1):98. Epub 2020 Apr 7.

School of Dentistry, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, San-Ming, District, Kaohsiung, 807, Taiwan.

Background: We aimed to investigate the load-induced strain variation in teeth with unrestored and resin-based composite restored non-carious cervical lesions (NCCLs).

Methods: Twelve extracted premolars were provided for measuring buccal-side root NCCLs. Strain gauges were fixed at four measuring sites of each tooth, two at the buccal surface and two at the lingual surface. Read More

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Enamel thickness and growth rates in modern human permanent first molars over a 2000 year period in Britain.

Am J Phys Anthropol 2020 09 20;173(1):141-157. Epub 2020 Feb 20.

Human Osteology Lab, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK.

Objectives: This study explores variation and trends in first molar enamel thickness and daily enamel secretion rates over a 2000 year period in Britain.

Methods: Permanent first molars (n = 89) from the Roman, Anglo-Saxon, and Medieval periods, as well as modern-day Britain, were analyzed using standard histological methods. Relative enamel thickness (RET) and linear measurements of cuspal and lateral thickness were calculated for mesial cusps. Read More

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September 2020

Effect of tooth preparation design on marginal adaptation of composite resin CAD-CAM onlays.

J Prosthet Dent 2020 Jul 29;124(1):88-93. Epub 2019 Oct 29.

Professor, Department of Prosthodontics, Peking University School and Hospital of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology, Beijing, PR China.

Statement Of Problem: Although different preparation designs have been proposed for onlays fabricated by computer-aided design and computer-aided manufacturing (CAD-CAM), their effect on marginal adaptation is unclear.

Purpose: The purpose of this in vitro study was to investigate the effect of tooth preparation designs on the marginal and internal adaptation of ceramic-reinforced composite resin CAD-CAM onlays.

Material And Methods: A traditional preparation with a heavy chamfer on the functional cusp and a contrabevel on the nonfunctional cusp and a shoulder preparation with equal reduction on all cusps were used for mesial-occlusal-distal (MOD) onlay preparations. Read More

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Endostructural morphology in hominoid mandibular third premolars: Discrete traits at the enamel-dentine junction.

J Hum Evol 2019 11 1;136:102670. Epub 2019 Oct 1.

School of Anthropology and Conservation, University of Kent, Canterbury, CT2 7NZ, UK; Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany; Evolutionary Studies Institute, University of the Witwatersrand, 1 Jan Smuts Avenue, Braamfontein, 2000, Johannesburg, South Africa.

The mandibular third premolar (P) exhibits substantial differences in size and shape among hominoid taxa, and displays a number of discrete traits that have proven to be useful in studies of hominin taxonomy and phylogeny. Discrete traits at the enamel-dentine junction (EDJ) can be accurately assessed on moderately worn specimens, and often appear sharper than at the outer-enamel surface (OES). Here we use microtomography to image the P EDJ of a broad sample of extant apes, extinct hominins and modern humans (n = 100). Read More

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November 2019

The deciduous dentition of Homo naledi: A comparative study.

J Hum Evol 2019 11 20;136:102655. Epub 2019 Sep 20.

Department of Anthropology, University of Arkansas, Fayetteville, AR 72701, USA.

In 2013, 2014 new hominin remains were uncovered in the Dinaledi chamber of the Rising Star cave system in South Africa. In 2015 Berger and colleagues identified these remains as belonging to a new species Homo naledi (Berger et al., 2015). Read More

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November 2019

Influence of Implant Inclination and Prosthetic Abutment Type on the Biomechanics of Implant-Supported Fixed Partial Dentures.

J Oral Implantol 2019 Oct 20;45(5):343-350. Epub 2019 Aug 20.

School of Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil.

Obtaining parallelism during implant placement is often difficult, leading to inclination of implants. The present study evaluated the stress distribution in 3-unit fixed partial dentures supported by 2 implants with different inclinations and prosthetic abutments. Universal castable long abutments (UCLAs) or tapered abutments were used considering 17° of implant angulation in different directions (mesial, distal, buccal, or lingual). Read More

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October 2019

Influence of infrastructure design and ceramic coverage material on stress development in posterior crowns.

Am J Dent 2019 Apr;32(2):99-104

São Leopoldo Mandic Institute and Dental Research Center, Campinas, São Paulo, Brazil,

Purpose: To evaluate the influence of the infrastructure design and type of ceramic coverage on residual stresses after occlusal loading of crowns with yttria-stabilized zirconium oxide (Y-TZP) infrastructure, analyzed by means of the finite element method.

Methods: 3D models of a mandibular first molar total crown were constructed with two different types of infrastructures: a coping with a uniform thickness of 0.3 mm, and an anatomic coping with a thickness ranging from 0. Read More

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Morphological study of upper wisdom tooth.

Rom J Morphol Embryol 2018 ;59(3):873-877

Department of Dental Medicine, Faculty of Medicine and Pharmacy, University of Oradea, Romania;

The article presents aspects of crown and root morphology of the superior wisdom teeth, aiming to several parameters: size, shape crown and occlusal surface, number, topography and orientation of the roots in order to determine which the most common morphological types are. For this purpose, the upper wisdom teeth were collected. According to studies, the dominant form of the dental crown is parallelepipedic, the rectangular or parallelogram shape of the occlusal surface has large mesial and distal-oriented sides. Read More

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January 2019

Orthodontic treatment of acquired open bite accompanied with extreme mesially inclined mandibular molars.

Int Orthod 2018 12 17;16(4):744-760. Epub 2018 Oct 17.

Department of Orthodontics, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan.

Acquired open bite mainly occurs after adolescence and is caused by a pathological or biological process. We herein report the case of an 18-year and 10-month-old Japanese woman. Her chief complaint was difficulty with mastication. Read More

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December 2018

Evidence for changing nerve growth factor signalling mechanisms during development, maturation and ageing in the rat molar pulp.

Int Endod J 2019 Feb 19;52(2):211-222. Epub 2018 Sep 19.

School of Dental Sciences, Newcastle University, Newcastle upon Tyne, UK.

Aim: To examine rat molar pulp innervation and identify complex cellular signalling systems involving nerve growth factor (NGF) and its p receptors (NGFR) at different stages of development, maturation and ageing.

Methodology: Decalcified mandibular first molar mesial cusps from Wistar rats of ages 0 day; 1, 2, 3, 4, 6, 9, 12 and 24 weeks (n = 5 per group) were sectioned (10 μm) and incubated with antibodies for NGF, NGFR, calcitonin gene-related peptide (CGRP) and neurofilament. Nerve densities in worn and intact regions of 3- to 24-week-old rats were compared by anova, Bonferroni and t-tests. Read More

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February 2019

Bilateral Scissor Bite Treated by Rapid Mandibular Expansion Following Corticotomy.

Bull Tokyo Dent Coll 2016 ;57(4):269-280

Department of Orthodontics, Tokyo Dental College.

Scissor bite is defined as buccal displacement of the maxillary posterior teeth, with or without contact between the lingual surface of the maxillary lingual cusp and the buccal surface of the buccal cusp of its mandibular antagonist. Here we report treatment of bilateral scissor bite in the posterior region using rapid expansion following corticot-omy. The patient was a boy aged 17 years and 11 months in whom skeletal maxillary prognathism with bilateral scissor bite was diagnosed. Read More

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January 2018

Impact of hypofunctional occlusion on upper and lower molars after cessation of root development in adult mice.

Eur J Orthod 2017 06;39(3):243-250

Department of Craniofacial Development and Stem Cell Biology, King's College London, London, UK.

Background: Hypofunctional occlusion is known to lead to changes in the length of roots over time. The mechanisms that drive such changes, however, are poorly understood, with most studies concentrating on juvenile rats prior to the arrest of root development. In this article, we investigated the response of the upper and lower first molar roots to lack of occlusion concentrating on time-points after the development of the roots has ceased using the mouse as a model. Read More

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Sex assessment efficacy of permanent maxillary first molar cusp dimensions in Indians.

Contemp Clin Dent 2015 Oct-Dec;6(4):489-95

Department of Orthodontics and Dentofacial Orthopedics, Mithila Minority Dental College and Hospital, Darbhanga, Bihar, India.

Background: The human first maxillary molar provides clues about evolution and is functionally important. It has four main cusps, and each cusp has an independent growth pattern and different evolutionary background. Though less explored, the analysis based on measurement of each cusp appears to be more meaningful biologically than conventional measurements of the whole crown. Read More

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December 2015

The role of APCDD1 in epithelial rearrangement in tooth morphogenesis.

Histochem Cell Biol 2015 Oct 14;144(4):377-87. Epub 2015 Jul 14.

Department of Biochemistry, School of Dentistry, IHBR, Kyungpook National University, 2177 Dalgubeol-daero, Joong-gu, Daegu, 700-412, Korea.

Adenomatosis polyposis coli downregulated 1 (APCDD1), a negative regulator of Wnt signaling, was examined to understand detailed mechanisms underlying Wnt signaling tooth development. In situ hybridization showed that Apcdd1 was expressed in the condensed mesenchyme at the bud stage, and in the inner enamel epithelium (IEE), including enamel knot (EK) at the cap stage. In vitro organ cultivation by using Apcdd1 antisense oligodeoxynucleotides was performed at E13. Read More

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October 2015

Revolution vs status quo? Non-intervention strategy of asymptomatic third molars causes harm.

Br Dent J 2015 Jul;219(1):11-2

School of Dentistry, JR Moore Builing, University of Manchester, Oxford Road, Manchester, M13 9PL.

The Faculty of Dental Surgery of the Royal College of Surgeons of England has prompted the National Institute for Health and Care Excellence to urgently re-assess the TA1 guidance on extractions of wisdom teeth and highlighted required amendments to the present version in light of published evidence concerning the harm caused by wisdom tooth retention. This article seeks to address the recent concerns relating the increasing frequency of distal-cervical caries in lower second molar teeth when associated with asymptomatic partially erupted mesial or horizontal impacted mandibular third molars. Such acute angle impactions are classified as partially erupted when one of the third molar cusps breached the epithelial attachment of the distal aspect of the second molar, thus prevents the formation of a gingival seal. Read More

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Hidden dental diversity in the oldest terrestrial apex predator Dimetrodon.

Nat Commun 2014 ;5:3269

Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, Ontario, Canada L5L 1C6.

Paleozoic sphenacodontid synapsids are the oldest known fully terrestrial apex predators. Dimetrodon and other sphenacodontids are the first terrestrial vertebrates to have strong heterodonty, massive skulls and well-developed labio-lingually compressed and recurved teeth with mesial and distal cutting edges (carinae). Here we reveal that the dentition of Dimetrodon and other sphenacodontids is diverse. Read More

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November 2015

Upper molar distalization with skeletally anchored TopJet appliance.

J Orofac Orthop 2014 Jan 19;75(1):42-50. Epub 2014 Jan 19.

Department of Orthodontics, Bernhard-Gottlieb School of Dentistry, Medical University Vienna, Sensengasse 2a, 1090, Vienna, Austria,

Objective: To retrospectively investigate clinical outcomes with the TopJet appliance.

Materials And Methods: Measurements were taken on dental casts reflecting situations in 15 patients aged 10-48 years before and after orthodontic treatment with a TopJet appliance. Each measurement was taken with a digital caliper and repeated 2 weeks later. Read More

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January 2014

[Three-dimensional finite element analysis of the effect of the location and diameter of implants on the stress distribution in three-unit implant-supported posterior cantilever fixed partial dentures under dynamic loads].

Hua Xi Kou Qiang Yi Xue Za Zhi 2013 Dec;31(6):552-6

Dept. of Prosthodontics, Stomatological Hospital of Shandong University, Jinan 250012, China.

Objective: To examine the effect of the location and diameter of implants on stress distribution in three-unit implant-supported posterior cantilever fixed partial dentures (FPD) in the mandible.

Methods: A three-dimensional finite element model was developed to represent a rigid implant-supported posterior FPD that restores the second left premolar, first molar, and second molar. The location of the distal implant with a diameter of 4. Read More

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December 2013

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

Am J Phys Anthropol 2013 Oct 5;152(2):186-96. Epub 2013 Sep 5.

Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, 11527, Greece.

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. Read More

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October 2013

A comparative evaluation of fracture resistance of endodontically treated teeth, with variable marginal ridge thicknesses, restored with composite resin and composite resin reinforced with Ribbond: an in vitro study.

Indian J Dent Res 2013 Mar-Apr;24(2):193-8

Department of Conservative Dentistry and Endodontics, Rural Dental College, Pravara Institute of Medical Sciences, Loni, Maharashtra, India.

Background: The anatomic shape of maxillary premolars show a tendency towards separation of their cusps during mastication after endodontic treatment. Preservation of the marginal ridge of endodontically treated and restored premolars can act as a strengthening factor and improve the fracture resistance.

Objectives: To evaluate the effect of varying thickness of marginal ridge on the fracture resistance of endodontically treated maxillary premolars restored with composite and Ribbond reinforced composites. Read More

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September 2015

Correlation between the frequency of eruption disorders for first permanent molars and the occurrence of malocclusions in early mixed dentition.

J Orofac Orthop 2012 Aug 11;73(4):298-306. Epub 2012 Jul 11.

Department of Orthodontics, School of Dentistry "Hans Moral", University of Rostock, Germany.

Objective: We analyzed the incidence of eruption disorders in 6-year molars during the first phase of mixed dentition, and then determined the risks for later dental arch development according to specific combinations of orthodontic malocclusions. We, thus, aimed to derive potential conclusions for preventative orthodontics.

Subjects And Methods: In this cross-sectional study, 8,041 kindergarten and school children with early mixed dentition were randomly selected and clinically examined. Read More

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Brief communication: Molar development and crown areas in early Australopithecus.

Am J Phys Anthropol 2012 Aug 24;148(4):632-40. Epub 2012 May 24.

Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA 90033, USA.

Recent studies suggest that the hypodigms representing the two earliest Australopithecus (Au. anamensis and Au. afarensis) form an ancestor-descendant lineage. Read More

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Three-year clinical follow-up of posterior teeth restored with leucite-reinforced ips empress onlays and partial veneer crowns.

J Prosthodont 2012 Jul 28;21(5):340-5. Epub 2012 Feb 28.

School of Dentistry, Universidad del Valle, Cali, Colombia.

Purpose: The aim of this study was to analyze the survival rate and failure mode of IPS leucite-reinforced ceramic onlays and partial veneer crowns regarding thickness under the following clinical conditions: vital versus nonvital teeth, tooth location, and type of opposing dentition.

Materials And Methods: Teeth were prepared according to established guidelines for ceramic onlays and partial veneer crowns. Before cementation, the restorations were measured for occlusal thickness at the central fossa, mesial, and distal marginal ridges, and functional and nonfunctional cusps. Read More

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Fracture resistance of root filled premolar teeth restored with direct composite resin with or without cusp coverage.

Int Endod J 2012 Jun 14;45(6):524-9. Epub 2012 Jan 14.

Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing, China.

Aim: To evaluate the fracture resistance and fracture patterns of root filled maxillary first premolar teeth (with mesio-occlusal cavity preparation) restored with several composite restoration designs.

Methodology: One hundred extracted sound human maxillary first premolars were randomly divided into five groups. Group 1 remained untreated (negative control). Read More

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Root canal morphology of mandibular first premolar in a gujarati population - an in vitro study.

Dent Res J (Isfahan) 2011 ;8(3):118-22

Professor, Department of Conservative Dentistry and Endodontics, K. M. Shah Dental College & Hospital, Gujarat, India.

Background: Knowledge about root canal morphology and its frequent variations can exert considerable influence on the success of endodontic treatment. The aim of this study was to survey the root canal morphology of mandibular first premolar teeth in a Gujarati population by decalcification and clearing technique.

Methods: One hundred thirty eight extracted mandibular first premolar teeth were collected from a Gujarati population. Read More

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November 2011

Evolutionary and developmental dynamics of the dentition in Muroidea and Dipodoidea (Rodentia, Mammalia).

Evol Dev 2011 Jul-Aug;13(4):361-9

Team Evo-Devo of Vertebrate Dentition, Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, UMR 5242 CNRS INRA UCBL ENS, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon Cedex 07, France.

When it comes to mouse evo-devo, the fourth premolar-first molar (P4-M1) dental complex becomes a source of longstanding controversies among paleontologists and biologists. Muroidea possess only molar teeth but with additional mesial cusps on their M1. Developmental studies tend to demonstrate that the formation of such mesial cusps could result from the integration of a P4 germ into M1 during odontogenesis. Read More

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October 2011

Risk of onlay fracture during pre-cementation functional occlusal tapping.

Dent Mater 2011 Sep 30;27(9):942-7. Epub 2011 Jun 30.

Department of Restorative Sciences, Herman Ostrow School of Dentistry of USC, University of Southern California, Oral Health Center, Los Angeles, CA 90089-7792, USA.

Objective: To evaluate in vitro the pre-cementation resistance of CAD/CAM onlays subjected to functional occlusal tapping.

Methods: An extracted tooth model (molar and premolar) with simulated bone and periodontal ligament was used to make a mesio-occlusal onlay preparation (two mesial cusps covered). Immediate dentin sealing was applied to the prepared tooth. Read More

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September 2011

Facial and dental alterations according to the breathing pattern.

J Appl Oral Sci 2011 Apr;19(2):175-81

Pontifcal Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil.

Unlabelled: There is controversy in the literature about possible interaction of the respiratory mode with the facial and dental structures.

Objectives: The aim of this study was to perform a longitudinal assessment of the changes in facial and dental structures in Angle's Class II, division 1 malocclusion individuals, divided according to the respiratory pattern (predominantly nasal or mouth), at two distinct moments of craniofacial development.

Material And Methods: Pogonium and nose measurements were made on the lateral cephalometric tracings (LS'-Pog', LS'-B', B'-Pog', Pog'-PogTeg', Line NB, Pog-NB, N'-Prn, Prn-NPog, N-Prn-Sn, Prn-Sn-LS). Read More

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What lies beneath? An evaluation of lower molar trigonid crest patterns based on both dentine and enamel expression.

Am J Phys Anthropol 2011 Aug 10;145(4):505-18. Epub 2011 Feb 10.

New York University, CSHO, New York, NY 10012, USA.

The nearly ubiquitous presence of a continuous crest connecting the protoconid and metaconid of the lower molars (often referred to as the middle trigonid crest), is one of several dental traits that distinguish Homo neanderthalensis from Homo sapiens. This study examined variation in trigonid crest patterns on the enamel and dentine surfaces to (1) evaluate the concordance between the morphology of trigonid crests at the inner dentine and the outer enamel surfaces; (2) examine their developmental origin(s); and (3) examine trait polarity through comparison with Australopithecus africanus and Pan. The sample included 73 H. Read More

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Enamel development in primary molars from children with familial dysautonomia.

Arch Oral Biol 2010 Nov 15;55(11):907-12. Epub 2010 Sep 15.

Hebrew University, Jerusalem, Israel.

Objectives: Familial dysautonomia (FD) is an autosomal recessive disorder, classified as a hereditary sensory and autonomic neuropathy type III, associated with growth defects affecting postnatal development. This study analysed prenatal and postnatal enamel development and postnatal calcification in upper second primary molars from FD children in comparison with healthy controls. The postnatal enamel of FD was also examined histologically for manifestation of growth insults. Read More

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November 2010