Evaluation of different types of polishing of composite resin surfaces after the removal of metal and ceramic brackets
Objective: To evaluate the effectivenessof different methods ofcomposite resin polishingafter the removaloforthodontic brackets. Material and Methods: 160resindiscsmade froma matrix ofacrylic resinwere divided into4 groups,according to thetype of composite resinused: G1 - microfilled(n = 40), G2 -microhybrid(n = 40), G3 -nanohybrid(n = 40)and G4-nanofilled(n = 40). One half of the samples wassubjectedto thermocycling, at 2000 cycles from 5 ? 2 ºC to 55 ? 2 ºC, for 1 min each. Halfof each group of resins was bonded with Gemini™ metallic brackets (3MUnitek) andthe otherhalf with Transcend™ ceramic brackets (3MUnitek). Thebrackets were transferred to auniversal testing machine (EMIC DLmodel2000).Half of the specimensfrom eachsubgroupwere polishedwith diamond burs andthe other halfwithSof-Lex discs. The averagesurface roughness of composite resin discswas measured,using aprofilometer,before the bondingof brackets, after the removal of brackets, after removing theexcess resinandafter polishing. Results: After removal of bracketsandafter polishing, the surface roughnesswas greater in the microhybridgroup(ANOVA, p < 0.05).After removalof ceramicbrackets, the groups showedhigher surfaceroughness (ANOVA, p < 0.05). There was no significantdifference inroughnessrelated tothermocyclingand the type ofpolishing.Conclusion:The qualityof thepolishis subjectedto the type ofresinused. Ceramicbrackets provided rougher surfacesafter removal. Both types ofpolishingusedare effective.