Short implants: Influence of different diameters, torques, and transmucosal heights of straight prosthetic abutments on screw preload loss after cycling

This study evaluated the influence of different implant diameters, insertion torques, and transmucosal heights on the loosening of abutments installed on short implants, after mechanical cycling. The Morse taper connection implants (n = 96) tested were 5 mm high, divided according to the platform diameter: 4 or 6 mm. A universal abutment was coupled to each implant (with different transmucosal heights: 1 or 5 mm). The sets were subdivided into 20- and 32-Ncm torque. After the cycle fatigue test, the detorque values were measured with a digital torque indicator. After mechanical cycling, the mean detorque values obtained for the abutment with 20-Ncm insertion torque were lower than for implants with 32-Ncm insertion torque, regardless of the platform diameter or transmucosal height. In the 20-Ncm torque group, there was no statistically significant difference in the detorque values between platform diameters or transmucosal heights. Otherwise, for 32-Ncm sets, a smaller platform diameter (4 mm), and a longer transmucosal height (5 mm) showed the lowest detorque values. In conclusion, implants placed with 32-Ncm insertion torque and abutments with 1 mm transmucosal height and a 6 mm implant diameter demonstrated the highest detorque values.