The assessment of abutment screw stability between the external and internal hexagonal joint under cyclic loading
이태식, 한중석, 양재호, 이재봉, 김성훈,
소속 상세정보
이태식 ( Lee Tae-Sik ) - 서울대학교 치과대학 치과보철학교실
한중석 ( Han Jung-Suk ) - 서울대학교 치과대학 치과보철학교실
양재호 ( Yang Jae-Ho ) - 서울대학교 치과대학 치과보철학교실
이재봉 ( Lee Jai-Bong ) - 서울대학교 치과대학 치과보철학교실
김성훈 ( Kim Seong-Hun ) - 서울대학교 치과대학 치과보철학교실
KMID : 0362420080460060561
Abstract
Statement of Problem: Currently, many implant systems are developed and divided into two types according to their joint connection: external or internal connection. Regardless of the connection type, screw loosening is the biggest problem in implant-supported restoration.
Purpose: The purpose of this study is to assess the difference in stability of abutment screws between the external and internal hexagonal connection types under cyclic loading.
Material and Methods: Each of the 15 samples of external implants and internal abutments were tightened to 30 N/cm with a digital torque gauge, and cemented with a hemispherical metal cap. Each unit was then mounted in a 30?.inclined jig. Then each group was divided into 2 sub-groups based on different periods of cyclic loading with the loading machine (30 N/ cm - 300 N/cm,14 Hz: first group 1 × 106, 5 × 106 cyclic loading; second group 3 × 106, 3 × 106 for a total cyclic loading of 6 × 106) The removal torque value of the screw before and after cyclic loading was checked. SPSS statistical software for Windows was used for statistical analysis. Group means were calculated and compared by ANOVA, independent t-test, and paired t-test with α = 0.05.
Results: In the external hexagonal connection, the difference between the removal torque value of the abutment screw before loading, the value after 1 × 106 cyclic loading, and the value after 1 × 106, and additional 5 × 106 cyclic loading was not significant. The difference between the removal torque value after 3 × 106 cyclic loading and after 3 × 106, and additional 3 × 106 cyclic loading was not significant. In the internal hexagonal connection, the difference between the removal torque value before loading and the value after 1 × 106 cyclic loading was not significant, but the value after 1 × 106, and additional 5 × 106 cyclic loading was reduced and the difference was significant (P < .05). In addition, in the internal hexagonal connection, the difference between the removal torque value after 3 × 106 cyclic loading and the value after 3 × 106, and additional 3 × 106 cyclic loading was not significant.
Conclusion: The external hexagonalconnection was more stable than the internal hexagonal connection after 1 × 106, and additional 5 × 106 cyclic loading (t = 10.834, P < .001). There was no significant difference between the two systems after 3 × 106, and additional 3 × 106 cycles.
키워드
Screw loosening;External hexagonal connection;Internal hexagonal connection;Cyclic loading
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