Pre-Load of Implant Screw: Effect of Methods Torque and Time

Objectives: To evaluate the influence of two methods of torque application and the effect of elapsed times for data collection on embedment relaxation phenomenon in Ceraone abutment screws. Methods: With an assistance of a modified parallelometer, thirty external hexagon implants (Conexão, Brazil) were embedded in acrylic resin, remaining 1.5 mm outside the resin on the implant cervical region. After, the Ceraone abutment screws were screwed on each implant (30 Ncm) with an assistance of a digital torquimeter (Lutron, Taiwan), with precision of ±1.5%. The detorque of the abutment screws was measured with a digital torquimeter. The specimens (sps) were divided into six groups according the factors “method of torque application” and “elapsed time for data collection” before detorque measured (n=5): Gr1- torque application + detorque data collection after 2 min (Gr1a), 5 min (Gr1b) and 10 min (Gr1c); Gr2- torque application + new torque application (retorquing) after 10 min + detorque data collection after 2 min (Gr2a), 5 min (Gr2b) and 10 min (Gr2c). The data obtained were analyzed statistically using the ANOVA two-way and Tukey's test (5%). Results: The means (±DP) of the detorque values observed for the experimental conditions were: Gr1a: 25.39±1.59Ncm; Gr1b: 22.91±1.74Ncm; Gr1c: 21.95±1.07Ncm; Gr2a: 28.16±2.92; Gr2b: 21.97±1.44; Gr2c: 21.21±2.91. The main factor “methods of torque application” was not significant statistically (p=0.6427). Regarding the “elapsed time” effect, the time 2 min (Gr1a and Gr2a) presented higher detorque values (p=0.0001) than the others times: 5 min (Gr1b and Gr2b) and 10 min (Gr1c and Gr2c), which were similar between them. The interaction effect was not significant statistically (p=0.1042). Conclusion: According the results of this study, it can be concluded that the abutment screws must be retorquing at least 5 minutes after the torque application.