By: Chun-Yeo Ha, Chang-Whe Kim,Young-Jun Lim, Kyung-Soo Jang
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.
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 & Methods:
Six different implant-abutment connection systems were used. The cement retained abutment and titanium screw of each system were assembled and tightened to 32 Ncm with 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 320 N, 14 Hz) 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.
Fig. A. Regular diameter implants, abutments, abutment screws and titanium crowns. Fig. B. Wide diameter implants, abutments, abutment screws and titanium crowns.
Results & Conclusion:
The results were as follows:
- The initial detorque values of six different implant-abutment connections were not significantly different (p > .05).
- The detorque values after one million dynamic cyclic loading were significantly different (p < .05).
- The SSII regular and wide implant both recorded the higher detorque values than other groups after cyclic loading (p < .05).
- Of the wide the initial detorque values of Avana Self Tapping Implant, MIS and Tapered Screw and the detorque values of MIS implant after cyclic loading were higher than their regular counterparts (p < .05).
- After cyclic loading, SSII regular and wide implants showed higher de torque values than before (p < .05).