The influence of tightening sequence and method on screw preload in implant superstructures

• Published in: The International journal of prosthodontics Vol. 27; no. 1; p. 76
• Main Authors: Al-Sahan, Maha M, Al Maflehi, Nassr S, Akeel, Riyadh F
• Format: Journal Article
• Language: English
• Published: United States 01-01-2014
• Subjects: Dental Implant-Abutment Design; Dental Marginal Adaptation; Dental Prosthesis Design; Dental Prosthesis Retention; Dental Prosthesis, Implant-Supported; Humans; Stress, Mechanical; Surface Properties; Torque
• ISSN: 0893-2174
• DOI: 10.11607/ijp.3306

This study evaluated the effect of six screw-tightening sequences and two tightening methods on the screw preload in implant-supported superstructures. The preload was measured using strain gauges following the screw tightening of a metal framework connected to four implants. The experiment included six sequences ([1] 1-2-3-4, [2] 4-2-3-1, [3] 4-3-1-2, [4] 1-4-2-3, [5] 2-3-4-1, and [6] 3-2-4-1), two methods (onestep, three-step), and five replications. Significant differences were found between tightening sequences and methods. In the three-step method, a higher total preload was found in sequences 2 (312 ± 85 N), 3 (246 ± 54 N), and 4 (310 ± 96 N). In the one-step method, a higher total preload was found in sequences 1 (286 ± 94 N), 5 (764 ± 142 N), and 6 (350 ± 69 N). It is concluded that the highest total screw preload was achieved when anterior implants of the superstructure were first tightened in one step, followed by posterior implants.