The effect of internal implant-abutment connection and diameter on screw loosening

Ha, Chun Yeo; Kim, Chang Whe; Lim, Young Jun; Jang, Kyung Soo

Abstract

STATEMENT OF PROBLEM: One of the common problems of dental implant prosthesis is the loosening of the screw that connects each component, and this problem is more common in single implant-supported prostheses with external connection, and in molars. PURPOSE: The purposes of this study were: (1) to compare the initial abutment screw detorque values of the six different implant-abutment interface designs, (2) to compare the detorque values of the six different implant-abutment interface designs after cyclic loading, (3) to compare the detorque values of regular and wide diameter implants and (4) to compare the initial detorque values with the detorque values after cyclic loading. MATERIAL AND METHODS: Six different implant-abutment connection systems were used. The cement retained abutment and titanium screw of each system were assembled and tightened to 32Ncmwith digital torque gauge. After 10 minutes, initial detorque values were measured. The custom titanium crown were cemented temporarily and a cyclic sine curve load(20 to 320N, 14Hz) was applied. The detorque values were measured after cyclic loading of one million times by loading machine. One-way ANOVA test, scheffe's test and Mann-Whitney U test were used. RESULTS: The results were as follows : 1. The initial detorque values of six different implant-abutment connections were not significantly different(p> 0.05). 2. The detorque values after one million dynamic cyclic loading were significantly different (p <0.05). 3. The SS-II regular and wide implant both recorded the higher detorque values than other groups after cyclic loading(p <0.05). 4. Of the wide implants, the initial detorque values of Avana Self Tapping Implant, MIS and Tapered Screw Vent, and the detorque values of MIS implant after cyclic loading were higher than their regular counterparts(p <0.05). 5. After cyclic loading, SS-II regular and wide implants showed higher detorque values than before(p <0.05).