A Stress Analysis of Teeth with Cemented Dowels -On the effect of cracks in roots-

Research Project

Project/Area Number	06671975
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	補綴理工系歯学
Research Institution	Matsumoto Dental College
Principal Investigator	AMARI Mitsuharu Matsumoto Dental College, Dentistry, Professor, 歯学部, 教授 (10067043)
Co-Investigator(Kenkyū-buntansha)	TSUCHIYA Soichiroh Matsumoto Dental College, Dentistry, Assistant, 歯学部, 助手 (70236909) YANAGIDA Fumishiro Matsumoto Dental College, Dentistry, Assistant, 歯学部, 助手 (60230265) KOSAKA Shigeru Matsumoto Dental College, Dentistry, Assistant, 歯学部, 助手 (40225412)
Project Period (FY)	1994 – 1995
Project Status	Completed (Fiscal Year 1995)
Budget Amount *help	¥1,700,000 (Direct Cost: ¥1,700,000) Fiscal Year 1995: ¥400,000 (Direct Cost: ¥400,000) Fiscal Year 1994: ¥1,300,000 (Direct Cost: ¥1,300,000)
Keywords	Dowels / Three dimentional finite element method / Crack tip stress intensity facters
Research Abstract	Abstract : Pressure was applied at a 45'angle from the lingual to the tooth axis at each tip of the crack in the abutment teeth (i.e.the upper left central incisor). During this time, by using a three dimensional finite element method, stress analysis of the cracks in roots were carried out. Based on the factors discovered, stress intensity factors KI (Opening mode), K II (In-plane shear mode), K III (Anti-plane shear mode) were observed. As a result of this research on the stress analysis of the mechanical effects on the tips of the cracks in the tested abutment teeth, the following results were obtained : 1. The values for K I and K II were approximately the same as those shown by Kataoka's two-dimentional finite element method. The larger the vertical cracks on the side around the dowel in the pressured lingual side became, the more liable the cracks in roots spread during the opening mode. 2. Concerning K III,the influence of the pressure on the tips of the cracks by the one point loading models were larger than the two points loading models.