PURPOSE: This study compared the maintenance of tightening torque in different retention screw types of implant-supported crowns. MATERIALS AND METHODS: Twelve metallic crowns in UCLA abutments cast with cobalt-chromium alloy were attached to external hexagon osseointegrated implants with different retention screws: group A: titanium alloy retention screw; group B: gold alloy retention screw with gold coating; group C: titanium alloy retention screw with diamond-like carbon film coating; and group D: titanium alloy retention screw with aluminum titanium nitride coating. Three detorque measurements were obtained after torque insertion in each replica. Data were evaluated by analysis of variance (ANOVA), Tukey's test (P < 0.05), and t test (P < 0.05). RESULTS: Detorque value reduced in all groups (P < 0.05). Group A retained the highest percentage of torque in comparison with the other groups (P < 0.05). Groups B and D retained the lowest percentage of torque without statistically significant difference between them (P > 0.05). CONCLUSIONS: All screw types exhibited reduction in the detorque value. The titanium screw maintained the highest percentage of torque whereas the gold-coated screw and the titanium screw with aluminum titanium nitride coating retained the lowest percentage.
PURPOSE: This study compared the maintenance of tightening torque in different retention screw types of implant-supported crowns. MATERIALS AND METHODS: Twelve metallic crowns in UCLA abutments cast with cobalt-chromium alloy were attached to external hexagon osseointegrated implants with different retention screws: group A: titanium alloy retention screw; group B: gold alloy retention screw with gold coating; group C: titanium alloy retention screw with diamond-like carbon film coating; and group D: titanium alloy retention screw with aluminum titanium nitride coating. Three detorque measurements were obtained after torque insertion in each replica. Data were evaluated by analysis of variance (ANOVA), Tukey's test (P < 0.05), and t test (P < 0.05). RESULTS: Detorque value reduced in all groups (P < 0.05). Group A retained the highest percentage of torque in comparison with the other groups (P < 0.05). Groups B and D retained the lowest percentage of torque without statistically significant difference between them (P > 0.05). CONCLUSIONS: All screw types exhibited reduction in the detorque value. The titanium screw maintained the highest percentage of torque whereas the gold-coated screw and the titanium screw with aluminum titanium nitride coating retained the lowest percentage.
Authors: María Prados-Privado; Sérgio A Gehrke; Rosa Rojo; Juan Carlos Prados-Frutos Journal: Med Biol Eng Comput Date: 2018-06-11 Impact factor: 2.602
Authors: Abraão M Prado; Jorge Pereira; Filipe S Silva; Bruno Henriques; Rubens M Nascimento; Cesar A M Benfatti; José López-López; Júlio C M Souza Journal: J Mater Sci Mater Med Date: 2017-03-20 Impact factor: 3.896
Authors: Maria Beatriz Bello Taborda; Gabriela Sumie Yaguinuma Gonçalves; Cecília Alves de Sousa; Wirley Gonçalves Assunção Journal: Int J Dent Date: 2021-11-18