title: Optimization of a procedure for rebonding dislodged orthodontic brackets.
abstract: The purpose of this study was to compare shear bond strength (SBS) of bonded and rebonded orthodontic brackets following a variety of commonly used conditioning treatments and using both light-cured and self-cured composite resin systems. Brackets debonded during the initial determination of SBS were rebonded after the removal of residual resin from enamel surfaces using five different treatments: (1) Remove residual resin using a tungsten carbide bur, re-etch enamel surface, then bond a new bracket; (2) Remove resin from the base mesh with micro-etching then rebond the same bracket, (3) Remove residual resin from the enamel surface using resin-removing pliers, recondition the enamel with an air-powder polisher, then bond a new bracket; (4) Remove residual resin using a rubber cup and pumice, then bond a new bracket; (5) Remove residual resin using pliers alone, then bond a new bracket. The results revealed that the light-cured system produced higher shear bond strength in the initial bond than the self-cured system (p<0.005). Reconditioning the enamel surfaces using a tungsten carbide bur and acid-etching gave the highest SBS (difference 5.8 MPa; p<0.01) and clinically favorable fracture characteristics. The data suggest that the optimal procedure for rebonding dislodged orthodontic brackets is to resurface the enamel using a tungsten carbide bur, acid-etch the enamel, and use a new or re-use an old bracket after microetching.
authors.affiliation: Department of Orthodontics, University of Toronto, Canada.
authors.forename: B
authors.initials: B
authors.lastname: Mui
authors.forename: P E
authors.initials: PE
authors.lastname: Rossouw
authors.forename: G V
authors.initials: GV
authors.lastname: Kulkarni
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding / Q000295:instrumentation / Q000379:methods*; D003743:Dental Enamel / Q000648:ultrastructure; D003777:Dental Prophylaxis / Q000295:instrumentation; D004868:Equipment Failure; D006801:Humans; D016910:Orthodontic Brackets; D010756:Phosphoric Acids / Q000008:administration & dosage; D013314:Stress, Mechanical; D013499:Surface Properties; D017973:Tungsten Compounds
chemical_list: D003188:Composite Resins; D010756:Phosphoric Acids; D017973:Tungsten Compounds; C002802:tungsten carbide; D017438:Bisphenol A-Glycidyl Methacrylate