Pengaruh Modifikasi Preparasi dan Sudut Konvergensi pada Gigi Penyangga Pendek terhadap Retensi dan Resistensi Koping Metal Gigi Tiruan Cekat

Abstract

Short abutment teeth that are planned for fixed denture restorations, can cause problems such as the loosening of the fixed restorations. Loosening of the restorations can be caused by inadequate retention and resistance factor. Retention is the quality inherent in the dental prosthesis acting to resist the forces of dislodgment along the path of placement, whereas resistance is the features of a tooth preparation that resists dislodgment along an axis other than the path of placement. The retention and resistance of fixed dentures greatly affected by the height of the crown, the angle of convergence, and the surface area of the axial wall. The shorter an abutment tooth, the retention and resistance of the fixed crown restoration will also decrease, proximal preparation modifications can be made to increase retention and resistance. The purpose of this study is to determine the effect of modification of preparation and convergence angle of short abutment teeth on the retention and resistance of metal copings of fixed denture teeth simultaneously. The research sample used was a prepared brass rod with a height dimension of 3 mm and a width of 11 mm, with a convergence angle of 10° and 22°. The preparation modifications used are groove or box preparation modifications. A total of 30 samples were divided into 6 groups (n = 5) based on the angle of convergence and preparation modification. Testing the value of retention and resistance using a universal testing machine (Torsee UTM AMU-10). The results of the ANOVA test on the group with convergence angles of 10° and 22° showed a value of p = 0.0001 which indicated the effect of preparation modification on retention and resistance. On the Independent t-test, groove and box preparation modifications with convergence angles of 10° and 22° showed a p value = 0.0001 which indicated an effect of preparation modifications on retention and resistance. This is due to the effect of the groove and box preparation modification will increase the surface area, increasing the adhesive surface area of the cement and the retention value. In terms of resistance, additional groove and box preparation will add the effect of mechanical interlocking that occurs between the metal coping and the metal abutment, resulting in metal coping samples can only being released if there is damage in the metal coping and/or abutment. From the results of this study, it can be concluded that in cases with short abutment teeth, the addition of preparation modifications in the form of grooves or boxes can significantly increase the retention and resistance values. The box shaped preparation modifications will provide higher retention and resistance values than the groove shaped preparation.