PURPOSE: To analyze the torque application on prosthetic abutment screws using different maintenance times, to determine an influence on the removal torque values. MATERIALS AND METH-ODS: A total of 40 external hexagon implants, 40 titanium screws, and 40 customized abutments were used. In group 1, the screws received a torque of 30 N·cm by instant torque application; in groups 2, 3, and 4, torque of 30 N·cm was applied and maintained for 10, 20, and 30 seconds, respectively. Removal torque was performed 10 minutes after torque application. Data were statistically analyzed using 1-way ANOVA and Tukey HSD test ( = 0.05). RESULTS: The mean and standard deviation (±SD) of removal torque values found were 11.61 ± 1.43 N·cm for group 1; 18.64 ± 1.71 N·cm for group 2; 21.62 ± 0.97 N·cm for group 3; and 21.48 ± 1.55 N·cm for group 4. Groups 3 and 4 exhibited statistically higher values than group 2, which demonstrated significantly higher values than group 1 (P < 0.05). CONCLU-SIONS: A torque of 30 N·cm applied for 20 seconds seemed to be the best option when considering the removal torque values of external hexagon implants. DOI: https://doi.org/10.1097/ID.0b013e31829e548dPosted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-89919 Accepted Version Originally published at: Sella, Gustavo Castellazzi; Lopes Pereira Neto, Armando Rodrigues; Maziero Volpato, Cláudia Angela; de Vasconcellos, Diego Klee; Pekkan, Gurel; Özcan, Mutlu (2013). Influence of different maintenance times of torque application on the removal torque values to loosen the prosthetic abutment screws of external hexagon implants. Implant Dentistry, 22 (5)
ABSTRACT: (178 WORDS)Purpose: To analyze the torque application on prosthetic abutment screws using different maintenance times, to determine an influence on the removal torque values.
Materials and Methods:A total of 40 external hexagon implants, 40 titanium screws and 40 customized abutments were used. In group 1, the screws received a torque of 30 Ncm by instant torque application; in groups 2, 3 and 4, torque of 30 Ncm was applied and maintained for 10, 20 and 30 seconds, respectively. Removal torque was performed 10 minutes after torque application.Data were statistically analyzed using one-way ANOVA and Tukey's HSD test (α = .05). Results:The mean and standard deviation (±SD) of removal torque values found were 11.61±1. The screw loosening may be related to several factors, including: screw tightening, quality of the prosthetic components, screw design, plastic deformation of contact surfaces and lack of passive fit. [10][11][12][13][14][15][16] To prevent this problem, a number of modifications have been used, including modification of the implant body abutment interface (external or internal hexagon or octagon), use of gold screws, torque-controlling devices, screw cements, and the use of a silicone obturator and washers between the prostheses and screws. 1,5,7,8,17,18 Also, centering the occlusal contact, flattening cuspal inclin...
