임플란트를 둘러싸고 있는 IV형의 재생된 골과 자연골 사이의 경계부에 대한 유한요소법적 분석

Abstract

ABSTRACT

Finite element analysis of the junction between the type Ⅳ regenerated bone surrounding a dental implant and its adjacent native bone

Sohn Kyeong-jun, D.D.S. Advisor: Prof. Kim Byung-ock, Ph.D. Department of Dentistry, Graduate School of Chosun University

Biomechanical influences play an important role in the longevity of bone around implants. The purpose of this study was to investigate the distribution of stress within the regenerated bone surrounding the implant using three dimensional finite element stress analysis. Using EMRC NISA DISPLAY Ver. 12 program (IronCAD LLC, USA), a program was written to generate a model simulating a cylindrical block section of the mandible 20 ㎜ in height and 10 ㎜ in diameter. The 4.1 X 11.5-㎜ and 5.0 x 11.5-㎜ screw implant system (OSSTEM US Ⅲ, Pusan, KOREA) was modeledused for this study, and was assumed to be 100% osseointegrated. And it was restored with gold crown with resin filling at the central fossa area. The implant was surrounded by the regenerated type IV bone, with 1.5 ㎜ and 3.0 ㎜ in width and 7 ㎜ apical to the platform of implant in length. And the regenerated bone was surrounded by type I, type II, and type III bone, respectively. The present study used a fine grid model incorporating elements of 336,985 and nodal points of 64,889. A load of 200N was applied at the 2 points on occlusal surfaces of the restoration, the central fossa (A point), and the functional cusp (B point), at a 90 degree angle to the vertical axis of the implant, respectively. The stress values were calculated in junction between the type Ⅳ regenerated bone and its adjacent native bone (1.5 ㎜ and 3.0 ㎜ away from the implant fixture). The results were as follows:

1. The stress generated from around wide type implant was decreased compared to that of around standard implant. 2. The stress distribution generated from around wide type implant was similar to that of around standard implant. 3. When the load was applied at point A and B, high stresses occurred in the crest and apex of the regenerated bone. But, the stress generated from the lingual side of implant was concentrated in the crest, middle and apex of the regenerated bone, exceptionally. 4. Lower stresses occurred in point A than in point B. 5. The stress values of model with 1.5 ㎜ of regenerated bone in width were similar to that of 3.0.

In summary, these data indicated that the stress generated from around implant placed into regenerated bone was greater than that around implant placed into native bone. Therefore, clinician should consider bone quality around the implant fixture when fabricated the implant prosthesis.