title: Relation between implant/abutment vertical misfit and torque loss of abutment screws.
abstract: 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 (alpha=0.05) between the misfit values (29.08 +/- 8.78 microm) 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.
authors.affiliation: Department of Dentistry, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
authors.forename: Gustavo Augusto Seabra
authors.initials: GA
authors.lastname: Barbosa
authors.forename: Sérgio Rocha
authors.initials: SR
authors.lastname: Bernardes
authors.forename: Flávio Domingues
authors.initials: FD
authors.lastname: das Neves
authors.forename: Alfredo Júlio
authors.initials: AJ
authors.lastname: Fernandes Neto
authors.forename: Maria da Glória Chiarello
authors.initials: Mda G
authors.lastname: de Mattos
authors.forename: Ricardo Faria
authors.initials: RF
authors.lastname: Ribeiro
mesh_terms: D000044:Dental Abutments; D003758:Dental Implantation, Endosseous / Q000009:adverse effects*; D015921:Dental Implants / Q000009:adverse effects*; D017268:Dental Prosthesis Retention / Q000295:instrumentation*; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D003765:Models, Dental; D017755:Prosthesis Fitting; D019415:Torque
chemical_list: D015921:Dental Implants