Effect of implant‒abutment connections on abutment screw loosening: An in vitro study

Abstract

<strong data-sider-select-id="081c64db-2a43-4c48-8894-b9fc10ad65fe">Background. The widespread use of dental implants as a predictable treatment choice has drawn attention to their complications as a major challenge despite their high clinical success rates. In this context, loosening of the abutment screw in posterior single crowns is the most common problem; the use of adequate preload and proper anti-rotational features at implant‒abutment interface appear to be two main solutions to such a problem. The present study evaluated the effect of implant‒abutment connections in four different implant systems before and after cyclic loading. <strong data-sider-select-id="b18b047b-9540-4964-acde-ac2d916927d9">Methods. Intra-Lock, Dentis, Xive, and Dio implant systems were used in this study. Each system underwent one million cycles of dynamic forces eight times with a magnitude of 110 N. For each specimen after tightening the screw with a torque of 32 Ncm, the detorque values were measured and recorded by a digital torquemeter after and before cyclic loading. Data were analyzed by Kolmogorov-Smirnov, Levene’s, one-way ANOVA, and post hoc Tukey tests. <strong data-sider-select-id="9eb220c0-697f-4c37-97a5-a6ba8ae80ceb">Results. Initial detorque values between the study groups showed significant differences (<em data-sider-select-id="9f378d54-2814-4f32-bfdf-eef912e97348">P<0.0001). Pairwise comparisons showed significantly lower primary detorque values in the Dentis system compared to the three other systems (<em data-sider-select-id="621ad3d9-c4cc-4847-bcd4-e8d651f227ea">P<0.0001). After cyclic loading, significant differences were observed between the study groups (<em data-sider-select-id="aa4dac61-0f32-4bdd-a49a-9737a5fdb1a6">P<0.0001). Pairwise comparisons of the groups showed significant differences between all the systems after loading. <strong data-sider-select-id="0ba9297a-6c2c-4bad-a159-912167bb438c">Conclusion. The type of implant‒abutment connection is an essential factor influencing the amount of abutment screw loosening.