Relation between implant/abutment vertical misfit and torque loss of abutment screws

• Main Author: Barbosa,Gustavo Augusto Seabra
• Publication Date: 2008
• Other Authors: Bernardes,Sérgio Rocha, Neves,Flávio Domingues das, Fernandes Neto,Alfredo Júlio, Mattos,Maria da Glória Chiarello de, Ribeiro,Ricardo Faria
• Format: Article
• Language: eng
• Source: Brazilian Dental Journal
• Download full: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-64402008000400013
• topic: dental prosthesis implant-supported; prosthesis fitting; torque

This study investigated whether there is a direct correlation between the level of vertical misfit at the abutment/implant interface and torque losses (detorque) in abutment screws. A work model was obtained from a metal matrix with five 3.75 x 9 mm external hex implants with standard platform (4.1 mm). Four frameworks were waxed using UCLA type abutments and one-piece cast in commercially pure titanium. The misfit was analyzed with a comparator microscope after 20 Ncm torque. The highest value of misfit observed per abutment was used. The torque required to loose the screw was evaluated using a digital torque meter. The torque loss values, measured by the torque meter, were assumed as percentage of initial torque (100%) given to abutment screws. Pearson's correlation (α=0.05) between the misfit values (29.08 ± 8.78 µm) and the percentage of detorque (50.71 ± 11.37%) showed no statistically significant correlation (p=0.295). Within the limitations of this study, it may be concluded that great vertical misfits dot not necessarily implies in higher detorque values.