コーヌスクローネ支台歯の挙動に関する基礎的研究 : 支台歯の咬合力負担形態の違いによる影響

Abstract

It has been reported that the Konuskrone-retained partial dentures have many advantages for abutment teeth. In most of the past reports, however, their effects on the abutment teeth were analyzed by loading only on the denture base. In the present study, the experimental apparatus consisting of a simulation model and a specified loading device was constructed so as to give a load through a food test piece on only the artificial teeth on the denture base or on both the artificial teeth and the Konus crown simultaneously, and the movements of the abutment teeth were analyzed. Six types of unilateral distal extension partial dentures involving unilateral and bilateral retainers were designed for Kennedy class II simulation model. The abutment tooth movements in those designs were three-dimensionally examined using laser displacement sensors. The results obtained were as follows : 1. In the unilateral designs, the horizontal abutment tooth movement for one abutment design could not be reduced by addition of one mesial abutment. One more mesial addition of abutment showed considerable reduction in the movement although it might have a risk of causing torsion moment between 〓 and 〓 Konuskrone retainers. 2. In the bilateral designs, addition of one mesial abutment tooth on the denture side was effective for reducing the movement ; one more mesial addition of abutment could further control the direction of the movement. 3. Little effects of the indirect retainers were found on the horizontal movement of the abutment tooth in the design having one abutment. The movement effectively decreased with increase in the number of abutment on the denture side. 4. In comparison of the designs having a given number of the abutment teeth, the bilateral designs showed more favorable behavior than the unilateral ones with two and three abutment teeth. 5. When the load was simultaneously applied to both the artificial teeth and Konus crowns, the distal movement of the abutment became smaller and the vertical movement larger than those observed in the case of the loading on only the artificial teeth, indicating more favorable stress bearing condition of the abutment teeth.