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Three-dimensional Finite Element Modeling of a Maxillary premolar Tooth Based on the Micro-CT Scanning: A Detailed Description

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Journal of Huazhong University of Science and Technology(Medical Sciences) 2013年第5期33卷 775-779页

作者：黄政陈智 Key Laboratory for Oral Biomedicine of Ministry of Education School and Hospital of Stomatology Wuhan University

This study describes the details of how to construct a three-dimensional （3D） finite element model of a maxillary first premolar tooth based on micro-CT data acquisition technique, MIMICS soft- ware and ANSYS software. The tooth was scanned by micro-CT, in which 1295 slices were obtained and then 648 slices were selected for modeling. The 3D surface mesh models of enamel and dentin were created by MIMICS （STL file）. The solid mesh model was constructed by ANSYS. After the material properties and boundary conditions were set, a loading analysis was performed to demonstrate the ap- plicableness of the resulting model. The first and third principal stresses were then evaluated. The re- suits showed that the number of nodes and elements of the finite element model were 56 618 and 311801, respectively. The geometric form of the model was highly consistent with that of the true tooth, and the deviation between them was ~）.28%. The loading analysis revealed the typical stress patterns in the contour map. The maximum compressive stress existed in the contact points and the maximum tensile stress existed in the deep fissure between the two cusps. It is concluded that by using the micro-CT and highly integrated software, construction of the 3D finite element model with high quality will not be difficult for clinical researchers.

关键词： three-dimensional finite element micro-CT premolar MIMICS ANSYS

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Double Roots of Mandibular premolar in Full-mouth Periapical Films

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Chinese Medical Sciences Journal 2015年第3期30卷 174-178页

作者： Ling-jia Kong Kuo Wan Deng-gao Liu Department of Stomatology Peking Union Medical College HospitalChinese Academy of Medical Sciences & Peking Union Medical College Department of Radiology Peking University School of Stomatology

Objective To evaluate the incidence of two-rooted mandibular premolar morphology using full-mouth periapical film series in a Chinese population,with particular emphasis on bilateral incidence,so as to provide a clinical anatomical basis for root canal treatment in mandibular *** A total of 2015 patients who underwent dental treatment and had full mouth periapical radiographs at the Peking University School of Stomatology from April 2011 to April 2012 were enrolled in this *** experienced dentists reviewed the patients' periapical films and classified the root morphology of mandibular premolars *** incidence of unilateral and bilateral double roots were recorded and calculated,including confirmed and suspected bucco-lingual root *** In terms of the morphology of two-rooted mandibular first premolars,of the 2015 cases with complete root formation,two-rooted first premolars were detected in 120 cases,with a total number of 159 *** to the number of teeth,the overall incidence of double roots was 4.03%(159/3972).In terms of the morphology of two-rooted mandibular second premolars,of the 2015 cases with complete root formation,two-rooted second premolars were detected in 24 cases,with a total number of 33 *** to the number of teeth,the overall incidence of double roots was 0.85%(33/3880).Conclusions The roots of mandibular premolars display specific morphological *** on a large sample,we observed and calculated not only the occurrence rate of bucco-lingual and mesio-distal double roots in first and second mandibular premolars,but also the incidence of unilateral or bilateral double roots within the same *** findings could provide useful information on the anatomical structure of mandibular premolars for endodontic,prosthodontic and surgical procedures,and could improve the quality of treatment and reduce complications.

关键词： first mandibular premolar second mandibular premolar double roots full-mouth periapical film

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Comparison of Chemical Elements on Carious &Normal premolar’s Enamel Layers Using Energy Dispersive X Ray Spectrometer (X Ray-EDS)

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Microscopy Research 2014年第4期2卷 81-91页

作者： A. Adabache- Ortiz M. Silva- Briano M. R. Campos- Esparza J. Ventura- Juárez Departamento de Biología Laboratorio de Microscopía de Alta Resolución del Centro de Ciencias Básicas Universidad Autónoma de Aguascalientes Aguascalientes México Departamento de Morfología Universidad Autónoma de Aguascalientes Aguascalientes México

Objectives: To compare the distribution of chemical elements among the carious and normal enamel layers on teenagers, using energy dispersive X ray spectrometer (EDS Rx). Materials and Methods: The EDS Rx analyzer is integrated to scanner electron microscope. The macro and mi-croelements were made in 30 premolars of teenager: 14 carious enamel layers and 16 normal enamel layers. Results: The quantitative and qualitative microanalyses of macro and microele-ments were found between the enamel layers of carious and normal premolar in term of variation and concentration expressed in percentage atomic weight. The statistical data analysis of ANOVA showed that the macroelements [C, Ca, P] and the microelements [Al, Cl, Mg, Na] were significantly different (P premolars. However, the deficiency or excess of these elements in the enamel layers determines the degree of susceptibility to carious and other dental disease. Clinical Relevance: The carious enamel in dental structure could be a major dental problem due to the deficiency or excess of macro and microele-ments which are responsible for secondary or recurrent caries, discoloration, pulpal inflammation, re-infection, abscess in jaw bone and dental disease.

关键词： Microelements Enamel premolar Caries EDS Rx

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Influence of incomplete ferrule on stress distribution of post and core restored maxillary premolar

Influence of incomplete ferrule on stress distribution of po...

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中华口腔医学会第14次全国口腔医学学术会议（2012年会）

Objective:This paper investigated the stress distribution of post and core restored maxillary premolar with limited residual tooth structure that forms only incomplete ***:CBCT based 3-D finite element analysis models of post and core restored maxillary premolar were set up,with 5 different ferrule designs(one with 360-degree circumferential axial,the other four with only 180-degree axial wall on different locations),PDL,and alveolar *** cast-metal post and prefabricated-fiber post were *** influence of incomplete ferrule is investigated through three-dimensional elastic finite element static analyses by comparison of the resulting stress field with crown restored model and complete ferrule model,under vertical and oblique *** stress measures were introduced to allow for the assessment of tooth fracture and interfacial-failure ***: Oblique load is more critical than vertical load for post and core restored *** with only facial ferrule shows highest stress concentration on dentin(72.415MPa), whereas tooth with only palatal ferrule shows stress distribution similar to tooth with complete ferrule(66.023MPa and 66.353MPa respectively),when restored with cast-metal *** value and concentration areas decreased for dentin when restored with glass fiber post,and did not show significant differences among different ferrule patterns,however maximal principal tress on fiber post and composite core was highest on tooth with only facial ***,incomplete ferrule induced increasing of shear stress level into interfaces for both post ***:For post and core restored teeth that cannot form complete ferrule,the location of remaining coronal tooth structure may affect the stress distribution under oblique load. The palatal axial wall for maxillary premolar is as effective as a circumferential axial wall in resisting oblique ***,teeth with only 180-degree axial wall show increased interface shear

关键词： post and core technique finite element analysis maxillary premolar

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Fracture resistance and pattern of the upper premolars with obturated canals and restored endodontic occlusal access cavities

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The Journal of Biomedical Research 2010年第6期24卷 474-478页

作者： Younong Wu Peter Cathro Victor Marino Dental Research Institute Nanjing Medical UniversityNanjingJiangsu 210029China School of Dentistry Faculty of Health SciencesUniversity of AdelaideSA 5005Australia

We studied whether obturing canals and restoring endodontic occlusal access cavities on upper premolars could provide acceptable resistance and pattern to *** upper premolars were divided equally into 3 *** 1 consisted of intact controls;group 2 had access cavities and root canal preparations;group 3 as in group 2 but obturated with gutta-percha and AH26,and the access cavity restored with glass ionomer and *** were submitted to compressive strength testing using the Hounsfield Universal H50KM testing machine with a load cell of 2000 Newtons and a crosshead speed set at 1.0 mm/min until *** results from the compressive strength tests showed that intact controls （1105.83±90.93 MPa） and restored premolars （936.67±44.67 MPa） were significantly different from premolars with unrestored access cavities 568.33±105.49 *** was no significant difference between intact controls and restored *** predominant fracture pattern for intact teeth was an oblique *** premolars that had endodontic access cavities,restored or unrestored,the most common fracture pattern was a vertical *** restoration of occlusal access cavities with glass ionomer and composite provided fracture resistance close to that of intact controls,but when restored teeth fractured,they were predominantly non-restorable.

关键词： root canal preparation premolar fracture

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Two-Phase Transplantation (TPTX) Concept: A New Approach for Instant Rehabilitation of Young Children after Avulsion of Central Incisor

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Open Journal of Stomatology 2017年第2期7卷 136-146页

作者： Dirk Nolte Claudia Tschammler Markus Henzler Robert Linsenmann Johannes Angermair Angermair Clinic for Oral and Maxillofacial Surgery Munich Germany Ruhr-University of Bochum Bochum Germany Department of Preventive Dentistry Periodontology and Cariology University of Gottingen Gottingen Germany Orthodontic Practice Munich Munich Germany

Background: To present a new idea for rapid management of tooth avulsion in young children and adolescents (age: 6 to 16) by this case report. Case presentation: A nine-year-old boy presented with loss of upper permanent central incisor in early mixed dentition (6 to 10 years, phase I). The not yet fully resorbed primary canine was used as tooth transplant for the lost incisor. The intentional renounce on endodontic treatment of the primary transplant permits natural exfoliation of the transplant occurring either spontaneously or due to undermining resorption through the adjacent erupting teeth. In the late mixed dentition (10 to 16 years, phase II), the primary tooth transplant is electively removed and replaced by a premolar autotransplant for long-term rehabilitation of the meanwhile adolescent patient. Results: Primary canine autoTX acts as a temporary denture with instant surgical gap closure. Ensuing premolar autoTX in phase II then acts as permanent denture with excellent 10 years survival rates. Patient satisfaction issued by a questionnaire resulted in good to very good school grades for both phases of autotransplantation. Conclusions: The “TPTX” concept is a new surgical approach that immediately restores the patient’s function and aesthetics after tooth loss in early childhood supporting the growth of local bone and soft tissue in the growing adolescent jaw.

关键词： Autogenous Tooth Transplantation premolar Primary Dentition Resorption Traumatic Dental Injury (TDI)

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