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Jia-de Wang

Publications and source records attributed to Jia-de Wang.

7 recordsLinked to original sources
PubMed2005

[Establishment of the three-dimensional finite element model of the first permanent mandibular molar and its stress analysis].

OBJECTIVE: To establish more rational three dimensional finite element model (FEM) of the first permanent mandibular molar and to study the internal stress distribution. METHODS: The FEM was applied to analyze the stress distribution of the first permanent mandibular molar under various loading conditions. RESULTS: Under all five loading conditions, the maximum von-Mises stress and compressive stress in enamel were larger than that in dentin, and the tensile stress in enamel was smaller than that in dentin. When vertical force and buccal-lingual oblique force were loaded, the stresses in the enamel and dentin were minimum; when lingual-buccal oblique force was loaded, the stresses were maximum; the stresses were mainly distributed at cervical region, furcation and apical area of the mesial-lingual root canal wall. CONCLUSIONS: The stress value changes and stress distribution in the enamel and dentin were closely related with the direction of the occlusion force.

Adult↗
PubMed2004

[Enamelin transcriptional expression in developing postnatal rat tooth germ].

OBJECTIVE: To observe the transcriptional expression of enamelin in developing postnatal rat first mandibular molar germs, for further studies of functions of enamelin in enamel development and mineralization. METHODS: Tissue slices of first mandibular molar germ of rat 1, 3, 7, 10, 14 days after birth were prepared. The enamelin mRNA expression was identified by in situ hybridization. RESULTS: Enamelin mRNA was observed in both ameloblast and odontoblast in 1-10 day old rat postnatal first mandibular molar germs. Enamelin mRNA appeared very weakly at 1st day, and increased through 3rd day, reached the maximum at 7th day, and reduced at 10th day and became negative at 14th day postnatally; while the expression of enamelin mRNA in odontoblast maintained lower from 1st to 10th day and negative at 14th day postnatally. CONCLUSION: Enamelin gene transcriptional expression lasts from preameloblast to maturation ameloblast, which suggests that enamelin may participate in the development of enamel and mantle dentin.

Ameloblasts↗
PubMed2004

[Preliminary study of tooth measured by a noncontact 3D image survey system].

OBJECTIVE: To perform the quantitative study of tooth occlusal surface wear by a noncontact 3D image survey system. METHODS: Thirty-two old people's complete dental casts in five years which had normal occlusion were studied. The same way was used to determine the individual reference surface, and the range of the maxillary first molar occlusal surface was delimited by the unite regulation. Then the quantity of wear in five years and wear rate of maxillary first molar occlusal surface were measured by the noncontact 3D image survey system. RESULTS: Wear of maxillary first molar occlusal surfaces was as follows: the mean height loss was 0.293 mm in five years and the mean wear rate was 0.059 mm/year; the mean volume loss was 97.881 mm(3) in five years and the mean wear rate was 19.576 mm(3)/year. CONCLUSIONS: Under the necessary conditions, the noncontact 3D image survey system is an effective method to measure the wear of dental occlusal surface, but some set-up conditions need to be improved further.

Adult↗
PubMed2003

[Two-dimensional finite element stress analysis of simulating restored teeth with wedge-shaped defects under loads].

OBJECTIVE: To study the concentration of stresses at the cervix with simulating restoration of tooth defects. METHODS: A two-dimensional finite element model of a mandible first premolar with defect from longitudinal section was developed. The model was simulatedly restored, respectively by composite resin and glass ionomer cement, and then investigated stress variation in the cervical area. RESULTS: In the restored models, both of materials improved the concentration of stresses at the cervical area. The composite resin and the glass ionomer cement restorations made the maximum principal stresses declined respectively to 36.2 MPa and 42.5 MPa, which were close to the value of normal tooth in the deepest area of defects. CONCLUSION: The concentration of stresses are improved in the cervical area with teeth defects restored.

Composite Resins↗