598 results match your criteria cusps molar

Fracture Resistance of Cement-retained, Screw-retained, and Combined Cement- and Screw-retained Metal-ceramic Implant-supported Molar Restorations.

J Contemp Dent Pract 2020 Aug 1;21(8):868-873. Epub 2020 Aug 1.

Center of Dental Medicine, Division of Dental Biomaterials, Clinic for Reconstructive Dentistry, University of Zurich, Zurich, Switzerland.

Aim: To compare fracture resistance between the cement-retained (CR), screw-retained (SR), and combined cement- and screw-retained (CCSR) metal-ceramic (MC) implant-supported molar restorations and the fracture mode after vertical loading simulation.

Materials And Methods: Thirty MC molar restorations were fabricated on thirty tilted dental implants that were repositioned using prefabricated or universal castable long abutments (UCLA) with 15° of angulation divided into three groups of ten specimens each. Group C: CR, group S: SR, and group CS: cement- and screw-retained. Read More

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[Three-dimensional finite element analysis of different framework materials in implant-supported fixed mandibular prosthesis].

Zhonghua Kou Qiang Yi Xue Za Zhi 2021 Feb;56(2):190-195

Department of Implantology, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan 250012, China.

To evaluate the biomechanical behaviors of different framework materials in implant-supported fixed mandibular prosthesis using three-dimensional finite element analysis. A model of implant-supported fixed mandibular prosthesis was established. The simulations were divided into six groups according to the framework materials: pure titanium, cobalt-chromium alloy, gold alloy, zirconia, polyether ether ketone (PEEK) and carbon fiber-reinforced PEEK. Read More

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February 2021

Morphological similarity and dental homologies in two sigmodontine rodents (Mammalia, Cricetidae) from different tribes: A topological analysis to explore convergence.

J Morphol 2021 Apr 16;282(4):563-573. Epub 2021 Feb 16.

Instituto de Diversidad y Evolución Austral (IDEAus-CONICET), CONICET, Puerto Madryn, Chubut, Argentina.

We present a topological analysis of the third upper molars (M3) using the recently developed ICAMER nomenclatural system as a way to understand the dental morphological similarity in sigmodontine rodents, the most speciose subfamily of cricetids. The method is explored in Scapteromys aquaticus and Abrothrix olivacea, taxa belonging to two diverse tribes, Akodontini and Abrotrichini, respectively, which exhibit high similarity regarding several craniodental traits as well as external anatomy. Both species show morphologically similar M3 in adults characterized by cylindrification and the isolation of a large central fossette arising from the marginal fusion of the anterior and posterior lobes. Read More

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[The Spatiotemporal Expression Patterns of Mechanical-Stress Related Regulatory Proteins in Mouse Molar Development].

Sichuan Da Xue Xue Bao Yi Xue Ban 2021 Jan;52(1):82-86

State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.

Objective: In order to better understand the role of mechanical stress in early tooth development, we examined the spatiotemporal expression patterns of mechanical-stress related regulatory protein (actin filament, or F-actin), non-muscle myosin ⅡB (NMⅡB) and vinculin at different stages of tooth development in mice.

Methods: Mouse first mandible molars were used as the research model. Immunofluorescence staining was performed to detect the expression patterns of F-actin, NMⅡB and Vinculin, the key molecules constituting the chemical mechanical system, at bud, cap, early bell and late bell stages of tooth. Read More

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January 2021

Anomalous incisor morphology indicates tissue-specific roles for Tfap2a and Tfap2b in tooth development.

Dev Biol 2021 Apr 15;472:67-74. Epub 2021 Jan 15.

Department of Biology, University of Florida, Gainesville, FL, USA; Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA. Electronic address:

Mice possess two types of teeth that differ in their cusp patterns; incisors have one cusp and molars have multiple cusps. The patterning of these two types of teeth relies on fine-tuning of the reciprocal molecular signaling between dental epithelial and mesenchymal tissues during embryonic development. The AP-2 transcription factors, particularly Tfap2a and Tfap2b, are essential components of such epithelial-mesenchymal signaling interactions that coordinate craniofacial development in mice and other vertebrates, but little is known about their roles in the regulation of tooth development and shape. Read More

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Mammalian molar complexity follows simple, predictable patterns.

Proc Natl Acad Sci U S A 2021 Jan 21;118(1). Epub 2020 Dec 21.

Department of Anthropology, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada.

Identifying developmental explanations for the evolution of complex structures like mammalian molars is fundamental to studying phenotypic variation. Previous study showed that a "morphogenetic gradient" of molar proportions was explained by a balance between inhibiting/activating activity from earlier developing molars, termed the inhibitory cascade model (ICM). Although this model provides an explanation for variation in molar proportions, what remains poorly understood is if molar shape, or specifically complexity (i. Read More

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January 2021

Anteroposterior skeletofacial classification and its relationship to maxillary second molar buccopalatal angulation.

Angle Orthod 2020 11;90(6):851-856

Objective: To compare second molar angulation to the occlusal plane with cephalometric measurements corresponding to AP skeletal discrepancy.

Materials And Methods: 72 patients' pre-orthodontic records were analyzed. A plane was constructed along the cusps of the upper second molar and measured to a proxy for the occlusal plane. Read More

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November 2020

Molar occlusion and jaw roll in early crown mammals.

Sci Rep 2020 12 24;10(1):22378. Epub 2020 Dec 24.

Section Palaeontology, Institute of Geosciences, Rheinische Friedrich-Wilhelms-Universität Bonn, Nussallee 8, 53115, Bonn, Germany.

Triconodontidae are considered the first carnivorous crown mammals. A virtual reconstruction of the masticatory cycle in the Late Jurassic Priacodon showed that triconodontid dental function is characterized by precise cutting on elongated crests. The combination of traits linked to both carnivorous diets (e. Read More

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December 2020

Mapping molar shapes on signaling pathways.

PLoS Comput Biol 2020 12 14;16(12):e1008436. Epub 2020 Dec 14.

Institute of Biotechnology and Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland.

A major challenge in evolutionary developmental biology is to understand how genetic mutations underlie phenotypic changes. In principle, selective pressures on the phenotype screen the gene pool of the population. Teeth are an excellent model for understanding evolutionary changes in the genotype-phenotype relationship since they exist throughout vertebrates. Read More

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December 2020

Buccolingual Inclination of Canine and First and Second Molar Teeth and the Curve of Wilson in Different Sagittal Skeletal Patterns of Adults Using Cone-Beam Computed Tomography.

Int J Dent 2020 31;2020:8893778. Epub 2020 Oct 31.

Students Research Committee, Faculty of Dentistry, Kermanshah University of Medical Sciences, Kermanshah 6715847141, Iran.

Objectives: This study aimed to assess the buccolingual inclination of canine and first and second molar teeth and the curve of Wilson in different sagittal skeletal patterns in untreated adults using cone-beam computed tomography (CBCT).

Materials And Methods: Sixty-six CBCT scans of adults (mean age: 28.74 ± 5. Read More

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October 2020

The earliest-known mammaliaform fossil from Greenland sheds light on origin of mammals.

Proc Natl Acad Sci U S A 2020 10 12;117(43):26861-26867. Epub 2020 Oct 12.

Department of Organismal Biology, Evolutionary Biology Centre, Uppsala University, 752 36 Uppsala, Sweden

Synapsids are unique in having developed multirooted teeth and complex occlusions. These innovations evolved in at least two lineages of mammaliamorphs (Tritylodontidae and Mammaliaformes). Triassic fossils demonstrate that close to the origins of mammals, mammaliaform precursors were "experimenting" with tooth structure and function, resulting in novel patterns of occlusion. Read More

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October 2020

A 3D finite element analysis of maxillary molar distalization using unilateral zygoma gear and asymmetric headgear.

Orthod Craniofac Res 2020 Oct 1. Epub 2020 Oct 1.

Department of Orthodontics, Near East University, Nicosia, Cyprus.

Objective: The aims of this study were (a) to evaluate the displacement and stress distribution in the maxillary dentition associated with the use of two different unilateral distalization appliances-unilateral zygoma gear (UZG) appliance and asymmetric headgear (AHG)-in non-growing patients; and (b) to assess the effects of fully erupted maxillary third molars on the distalization of the first molar with both appliances by using three-dimensional finite element analysis.

Settings And Sample Population: Two 3D models of the maxilla were created: one with third molars and one without. Next, two distalizing appliances (UZG and AHG) were added to each model to create four models. Read More

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October 2020

Fracture resistance of extensive bulk-fill composite restorations after selective caries removal.

Braz Oral Res 2020 28;34:e111. Epub 2020 Aug 28.

Graduate Program in Dentistry, Universidade Federal de Sergipe, Aracaju, SE, Brazil.

This study evaluated the effect of selective carious tissue removal on the fracture strength and failure mode of composite restorations in molars presenting only the buccal cusps. Deep cavities were prepared on the occlusal surface, and the lingual cusps were removed. Carious lesions in the middle of the pulpal wall were artificially induced with acetic acid (pH = 4. Read More

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October 2020

Prospective clinical evaluation of 765 partial glass-ceramic posterior restorations luted using photo-polymerized resin composite in conjunction with immediate dentin sealing.

Clin Oral Investig 2021 Mar 12;25(3):1463-1473. Epub 2020 Aug 12.

Department of Restorative Dentistry and Biomaterials, Center for Dentistry and Oral Hygiene, University Medical Center Groningen, Antonius Deusinglaan 1, 9713, AV, Groningen, The Netherlands.

Objectives: To evaluate the clinical performance of partial glass-ceramic (IPS e.max Press) posterior restorations.

Materials And Methods: A total of 765 restorations in 158 patients were placed between 2008 and 2018 and evaluated in a prospective study during regular dental care visits between 2015 and 2018. Read More

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Mesenchymal Bmp7 Controls Onset of Tooth Mineralization: A Novel Way to Regulate Molar Cusp Shape.

Front Physiol 2020 3;11:698. Epub 2020 Jul 3.

School of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.

Investigating the molecular basis for tooth shape variation provides an important glimpse into the evolution of tooth function. We recently showed that loss of mesenchymal BMP7 is sufficient to alter morphology and function of the toothrow. Here we report on the underlying mechanism. Read More

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Transverse Ridge of Premolars and Oblique Ridge of Maxillary Molars are in Divine Golden Ratio.

J Contemp Dent Pract 2020 May 1;21(5):486-489. Epub 2020 May 1.

Department of Maxillofacial Surgery and Diagnostic Sciences, Division of Oral Pathology, College of Dentistry, Jazan University, Jazan, Kingdom of Saudi Arabia.

Aims: In premolars and molars, transverse ridge (TR) and oblique ridge (OR) play major roles in providing strength and stability to the cusps in particular and tooth as a whole. Hence, they could be divided at the central groove or the transverse groove in a divine golden ratio.

Materials And Methods: Twenty pairs of maxillary and mandibular casts were retrieved from the Department of Orthodontics. Read More

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The functional role of the Carabelli trait in early and late hominins.

J Hum Evol 2020 08 21;145:102816. Epub 2020 Jun 21.

Department of Paleoanthropology, Senckenberg Research Institute and Natural History Museum Frankfurt, Senckenberganlage 25, 60325 Frankfurt a. M., Germany; Department of Paleobiology and Environment, Institute of Ecology, Evolution, and Diversity, Johann Wolfgang Goethe University, Max-von-Laue-Str. 13, 60438, Frankfurt, Germany.

The Carabelli trait is a dental feature that forms along the lingual margin of the protocone of deciduous and permanent maxillary molars. It is variably expressed, ranging from a small pit or furrow to a large cusp, and its development seems to be associated with crown size and molar cusp spatial configuration. The degree of expression of the Carabelli trait differs systematically between hominin taxa, and for this reason, it has been used extensively in the reconstruction of their phylogeny. Read More

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Chewing, dental morphology and wear in tapirs (Tapirus spp.) and a comparison of free-ranging and captive specimens.

PLoS One 2020 15;15(6):e0234826. Epub 2020 Jun 15.

Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.

Feeding practice in herbivorous mammals can impact their dental wear, due to excessive or irregular abrasion. Previous studies indicated that browsing species display more wear when kept in zoos compared to natural habitats. Comparable analyses in tapirs do not exist, as their dental anatomy and chewing kinematics are assumed to prevent the use of macroscopic wear proxies such as mesowear. Read More

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September 2020

Crown tissue proportions and enamel thickness distribution in the Middle Pleistocene hominin molars from Sima de los Huesos (SH) population (Atapuerca, Spain).

PLoS One 2020 8;15(6):e0233281. Epub 2020 Jun 8.

Centro Nacional de Investigación sobre la Evolución Humana, Burgos, Spain.

Dental enamel thickness, topography, growth and development vary among hominins. In Homo, the thickness of dental enamel in most Pleistocene hominins display variations from thick to hyper-thick, while Neanderthals exhibit proportionally thinner enamel. The origin of the thin trait remains unclear. Read More

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Two-body wear test of enamel against laboratory polished and clinically adjusted zirconia.

J Mech Behav Biomed Mater 2020 08 7;108:103760. Epub 2020 Apr 7.

Faculty of Dentistry, University of Sydney, NSW, 2006, Australia.

Aim: A two-body wear test experiment was performed on human enamel, in simulated chewing motion, against non-veneered zirconia ceramic. Aim-1 was to ascertain the effect of zirconia roughness on enamel wear. Aim-2 was to ascertain the relative enamel wear between enamel-zirconia wear pair and enamel-enamel control pair. Read More

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Prevalence of Selected Non-Metric Dental Traits in Indo-Nepalese and Tibeto-Nepalese Ethnic Groups of Western Hilly Region.

JNMA J Nepal Med Assoc 2019 Sep-Oct;57(219):323-326

Department of Forensic Medicine and Toxicology, Lumbini Medical College and Teaching Hospital, Palpa, Nepal.

Introduction: Additional anatomic features present on teeth are called non-metric dental traits. Carabelli's cusp and shovelling are such traits which are mostly evaluated for identification of ethnicity. The present study aims to determine the prevalence of Carabelli's cusp and shovelling among Indo-Nepalese and Tibeto-Nepalese ethnic group. Read More

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The history of mesowear: a review.

PeerJ 2020 13;8:e8519. Epub 2020 Feb 13.

Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.

Published mesowear data was reviewed from the year 2000 to November 2019 (211 publications, 707 species, 1,396 data points). Mesowear is a widely applied tooth wear technique that can be used to infer a herbivore's diet by scoring the height and sharpness of molar tooth cusps with the naked eye. Established as a fast and efficient tool for paleodiet reconstruction, the technique has seen multiple adaptations, simplifications, and extensions since its establishment, which have become complex to follow. Read More

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February 2020

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

Were ancient foxes far more carnivorous than recent ones?-Carnassial morphological evidence.

PLoS One 2020 10;15(1):e0227001. Epub 2020 Jan 10.

Operational Direction "Earth and History of Life", Royal Belgian Institute of Natural Sciences, Brussels, Belgium.

Crown shape variation of the first lower molar in the arctic (Vulpes lagopus) and red foxes (Vulpes vulpes) was analyzed using five groups of morphotypes. Carnassial morphologies were compared between the species and between spatially and temporally distant populations: one Late Pleistocene (n = 45) and seven modern populations of the arctic fox (n = 259), and one Late Pleistocene (n = 35) and eight modern populations of the red fox (n = 606). The dentition of Holocene red foxes had larger morphotype variability than that of arctic foxes. Read More

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Determining primates bite force from histological tooth sections.

Herzl Chai

Am J Phys Anthropol 2020 04 8;171(4):683-703. Epub 2020 Jan 8.

School of Mechanical Engineering, Tel-Aviv University, Tel-Aviv, Israel.

Objectives: The ability to accurately estimate bite force (BF) in extant and fossil primates is valuable to biological anthropologists. BF is generally evaluated using complex jaw musculature and lever arm analyses employing numerous assumptions and requiring complete cranial morphology. Here, a simple method to determine BF from data measured on histological sections of fossil teeth is proposed. Read More

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Comparative dental anatomy in newborn primates: Cusp mineralization.

Anat Rec (Hoboken) 2020 09 1;303(9):2415-2475. Epub 2020 Jan 1.

School of Physical Therapy, Slippery Rock University, Slippery Rock, Pennsylvania.

Previous descriptive work on deciduous dentition of primates has focused disproportionately on great apes and humans. To address this bias in the literature, we studied 131 subadult nonhominoid specimens (including 110 newborns) describing deciduous tooth morphology and assessing maximum hydroxyapatite density (MHD). All specimens were CT scanned at 70 kVp and reconstructed at 20. Read More

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September 2020

Fracture behavior of root-amputated teeth at different amount of periodontal support - a preliminary in vitro study.

BMC Oral Health 2019 11 27;19(1):261. Epub 2019 Nov 27.

Department of Operative and Esthetic Dentistry Faculty of Dentistry, University of Szeged, Tisza Lajos Krt., 64-66, Szeged, H-6720, Hungary.

Background: The purpose of this study was to evaluate the effect of the amount of periodontal support on the fracture resistance of root-amputated maxillary molar teeth restored with either direct class. I. restorations or class II. Read More

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November 2019

First record of a fossil monkey (Primates, Cercopithecidae) from the Late Pliocene of Serbia.

J Hum Evol 2019 12 16;137:102681. Epub 2019 Oct 16.

Department of Anthropology, University of Winnipeg, 515 Portage Avenue, Winnipeg, Manitoba, R3B 2E9, Canada.

The cercopithecid fossil record of the Balkan Peninsula extends from the Late Miocene to the Early Pleistocene, but to date no fossils of non-human primates have been identified in Serbia. Here we report the identification of two primate teeth from Ridjake, a rich paleontological site in western Serbia. NHMBEO 042501 is an upper third molar with heavy occlusal wear and taphonomic weathering. Read More

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December 2019

Three-dimensional evaluation of morphology and position of impacted supernumerary teeth in cases of cleidocranial dysplasia.

Congenit Anom (Kyoto) 2020 Jul 23;60(4):106-114. Epub 2019 Oct 23.

Maxillofacial Orthognathics, Department of Maxillofacial Reconstruction and Function, Division of Maxillofacial/Neck Reconstruction, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.

Cleidocranial dysplasia (CCD) is a congenital anomaly characterized by the presence of impacted supernumerary teeth and delayed eruption of permanent teeth. However, there has been no detailed investigation on supernumerary teeth in patients with CCD using three-dimensional (3D) imaging techniques. The purpose of this study was to elucidate the morphology and position of supernumerary teeth using 3D images reconstructed from cone-beam computed tomography (CBCT) data in a group of five Japanese subjects (male, 3; female, 2; age, 15. Read More

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Odontometric sex discrimination in young Urhobo adults of South-South Nigeria.

Anat Cell Biol 2019 Sep 26;52(3):269-277. Epub 2019 Aug 26.

Department of Human Anatomy and Cell Biology, Faculty of Basic Medical Sciences, College of Health Sciences, Delta State University, Abraka, Nigeria.

The spate of unidentified human remains as a result of kidnapping, killings, and so forth was the reason for this study. The purpose of this study was to measure the crown and cusps of each of the permanent maxillary first two molars to determine discriminant score and functions among Urhobo people of Nigeria. All Undergraduates of the Delta State University, Abraka, who are pure breeds Urhobo, form the study population. Read More

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September 2019