후방 유리단 국소의치에서 최후방 임프란트 식립에 따른 광탄성학적 응력 분석

Abstract

The purpose of this study was to compare and evaluate the magnitude and distribution of stress around the abutment teeth and on the residual ridge and on implant produced by three kinds of the mandibular bilateral free-end removable partial denture and tooth-implant supported removable partial dentures. For this study, a three-dimensional photoelastic stress analysis method was used. Mandibular photoelastic epoxy models remaining mandibular anterior teeth and bilateral free-end removable partial denture and tooth-implant supported removable partial dentures were fabricated using clasp with implant(C-IRPD), Konus crown with implant(K-IRPD). Bilateral removable partial dentures were positioned on the photoelastic epoxy resin models, and the vertical load of 60Ncm was applied on the central fossa of mandibular right the 1st molar artificial tooth of the every removable partial dentures. After photoelastic epoxy resin models with applied stress were frozen in a stress freezing furnace according to the stress freezing cycle, these models were sliced mesio-distally with a thickness of 6㎜. The sliced specimens were examined with the polariscope and transmission photoelastic device to observe the distribution of stress.

The results were as follows : 1. The isochromatic maximum fringe order number from C to M point was in the decreasing order of CRPD, C-IRPD, K-IRPD 2. On the root apex of the canine, the fringe order number was in the decreasing order of CRPD, C-IRPD, K-IRPD 3. Under premolar area of artificial tooth and on the residual ridge just below the loading point, the fringe order number was in the decreasing order of CRPD, C-IRPD, K-IRPD. 4. On the apex of the posterior implant, the fringe order number of K-IRPD was more higher than C-IRPD. 5. On the apex of the posterior implant, the fringe order number was more higher at the mesial side than at the distal side because of implant placement inclination and torque from occlusal force.

In conclusion, comparing control group with experimental group in view of stress distribution, occlusal force distribution effect was very considerable from implant placement at posterior area. in addition, K-IRPD using konus crown that used non-resilient connection type between implant and denture base was more favorable than C-IRPD because less stress concentration was showed on the canine and residual ridge, but it was unfavorable about implant itself at the stress distribution aspect because it showed very high stress concentration on implant.