title: Evaluation of screw loosening on new abutment screws and after successive tightening.
abstract: This study evaluated the loss of the torque applied after use of new screws and after successive tightening. Four infrastructures (IE), using UCLA castable abutment type, were cast in cobalt-chromium alloy and new abutment screws (G1) were used in a first moment. Subsequently, the same abutment screws were used a second time (G2) and more than two times (G3). The values of the torques applied and detorques were measured with a digital torque wrench to obtain the values of initial tightening loss (%). Data were analyzed by ANOVA and Tukey's test (?=0.05). Significant differences were observed between the G1 (50.71% ± 11.36) and G2 (24.01% ± 3.33) (p=0.000) and between G1 (50.71% ± 11.36) and G3 (25.60% ± 4.64) (p=0.000). There was no significant difference between G2 and G3 (p=0.774). Within the limitations of the study, it may be concluded that the percentage of the initial torque loss is lower when screws that already suffered the application of an initial torque were used, remaining stable after application of successive torques.
authors.affiliation: Department of Occlusion, Dental School, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
authors.forename: Gustavo Seabra
authors.initials: GS
authors.lastname: Barbosa
authors.forename: João Paulo da
authors.initials: JP
authors.lastname: Silva-Neto
authors.forename: Paulo Cezar
authors.initials: PC
authors.lastname: Simamoto-Júnior
authors.forename: Flávio Domingues das
authors.initials: FD
authors.lastname: Neves
authors.forename: Maria da Gloria Chiarello de
authors.initials: Mda G
authors.lastname: Mattos
authors.forename: Ricardo Faria
authors.initials: RF
authors.lastname: Ribeiro
mesh_terms: D002858:Chromium Alloys; D003035:Cobalt; D000044:Dental Abutments; D015921:Dental Implants; D017268:Dental Prosthesis Retention / Q000295:instrumentation*; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D017743:Equipment Reuse; D006801:Humans; D008334:Mandible; D003765:Models, Dental; D019415:Torque
chemical_list: D002858:Chromium Alloys; D015921:Dental Implants; D003035:Cobalt