임플란트 고정체 지대주 연결구조에 따른 치조골의 유한요소응력 분석

Abstract

ABSTRACT

Finite Element Stress Analysis of Alveolar Bone according to the Various Connections of Implant Fixture-Abutment

Byun, Wook, D.D.S. Advisor: Prof. Kang, Dong Wan, D.D.S., M.S.D., Ph.D. Department of Dentistry, Graduate School of Chosun University

The purpose of this study was to make a qualitative comparison and evaluation by means of 3D finite element analysis, the stress distribution produced by simulated different load applied against three types of internal connection implant system(one stepped and two tapered type). The finite element model was designed with the parallel placement of the one fixtures (4.0 mm × 11.5 mm) with isosceles trapezoidal thread on the mandibular 1st molar. The inner cancellous bone and the outer 3 mm cortical bone were designed, As the bone quality, and the cortical and cancellous bone were assumed to have bonded perfectly to the implant fixture.

Two models were loaded with 200 N magnitude in the vertical directions on the loading point position of the crown on the 0.0mm, 1.5 mm and the 3.0 mm buccal offset point from the central position of the fixture. The distributed oblique load was applied at the angle of 30° on the crown surface. Von Mises stress value was recorded and compared in the fixture-bone interface in the bucco-lingual dimension.

The results were as follows; 1.As the loading condition was away from the central position of implant fixture, stress pattern was concentrated as crater form in the cortical bone around the loading side on the neck of the fixture. 2.In comparison between the 3.0 mm offset vertical loading and the distributed oblique loading models with the 50% fixture- abutment interface, the stepped model had more mechanical stability with the reduced max. stress. On the other hand, 11° and 5.74° tapered models showed a increased max. stress compared to the stepped type of internal connection. 3.As the contact of fixture-abutment interface to the inner wall of implant fixture was increased, the stress concentration was reduced.

It was concluded that the offset loading condition was a key factor affecting the pattern and magnitude of stress over the surrounding bone of the fixture under the vertical and oblique loading conditions. It is recommended to place the dynamic occlusal contacts within the width of the neck of implant fixture.