임플랜트와 지대주 간 내측연결 시스템에서 friction fit와 slip fit에 따른 유한요소 응력분석

Abstract

Finite Element Stress Analysis of Implant Prosthesis according to Friction Fit or Slip Fit of Internal Connection between Implant and Abutment

Jang, Doo-Ik, D.D.S., M.S.D. Advisor: Prof. Chung, Chae-Heon, D.D.S., M.S.D., Ph.D. Dept of Dentistry, Graduate School of Chosun University

The purpose of this study was to assess the stress-induced pattern at the supporting bone, the implant fixture, the abutment and the abutment screw according to a friction-fit joint (Astra; Model 1) or slip- fit joint (Frialit-2; Model 2) in the internal connection system under vertical and inclined loading using finite element analysis. This study simulated loads of 200N at the central fossa in the vertical direction (loading condition A); at the functional cusp tip in a 15° inward inclined direction (loading condition B); and at the functional cusp tip in a 30°outward inclined direction (loading condition C).

The following results have been made based on this study:

1. There were generally stresses increased in case of the loading condition B and C of the inclined loading. Especially the greatest stress showed in the loading condition C with the inclined loading of outward direction from the centric cusp tip. Also, the cortical bone demonstrated a greater deal of stress than the stress measured on the cancellous bone. 2.Without regarding the loading condition, there was a greater magnitude of stress at the cortical bone contacting the upper part of the implant fixture, while a lower magnitude of stress was measured at the cancellous bone. When the stresses on the cortical bone were compared, there was generally a higher level of stress in Model 1 than in Model 2 according to the model condition. 3.The stress distribution pattern of the implant fixture was generally widely distributed along the inner surface of the implant fixture contacting the abutment core. Without regarding the loading condition, the magnitude of the stress on the implant fixture in Model 1 was higher than in Mode 2. 4.The stress distribution pattern of the abutment showed that a high magnitude of stress was generally concentrated at the neck of the abutment and the abutment core in the inclined loading cases of B, C and also this stress was notably distributed towards the lower part of the abutment core. Without regarding the loading condition, the magnitude of the stress on the abutment in Model 1 was higher than in Mode 2. 5.Without regarding the loading condition, the abutment screws in both Model 1 and Model 2 had a low magnitude of stress, because the stress in the internal connection cases was widely distributed along inner surface of implant fixture contacting abutment core. The magnitude of the stress on the abutment screws in Model 1 was higher than in Mode 2 without regarding the loading condition. 6.The stress was inclined to be directly distributed from the abutment core to the implant fixture in the internal connection system. Specifically, Model 1 of the friction-fit system tightly contacted between the abutment and the implant fixture had generally more stress than Model 2 of the slip-fit system in the supporting bone, the implant fixture, the abutment, and the abutment screw.

In conclusion, in the internal connection system of the implant and the abutment connection methods, the stress-induced pattern at the supporting bone, the implant fixture, the abutment and the abutment screw according to the abutment connection form had difference among them, and the stress distribution pattern usually had a widely distributed tendency along the inner surface of the implant fixture contacting the abutment core. The magnitude of the stress distributed in the supporting bone, the implant fixture, the abutment and the abutment screw was higher in the friction-fit joint than in the slip-fit joint. But it is considered that the further study is necessary about how this difference in the magnitude of the stress have an effect on the practical clinic.