title: Shear bond strength of rebonded brackets after removal of adhesives with Er,Cr:YSGG laser.
abstract: This study was conducted to examine the bond strength of rebonded orthodontic brackets after adhesive residuals on the surface of the bracket bases were removed by Er,Cr:YSGG lasers. Seventy-six brackets bonded to premolars with a self-etching primer adhesive system were equally divided into four groups after the first debonding with the bracket bases (Group 1) untreated, and treated by (Group 2) Er,Cr:YSGG laser, (Group 3) sandblaster, and (Group 4) Er,Cr:YSGG laser/sandblaster. The treated brackets were rebonded to the new premolars in the same manner as the first-stage experiment. The shear bond strengths were measured, with the bonding/debonding procedures repeated once after the first debonding, and the bracket/adhesive failure modes were evaluated after each debonding. The treated bracket base surfaces were observed under a scanning electron microscopy (SEM). The mean rebond strengths were significantly lower in group 1 than in other groups, and there were no significant differences between the other groups. The mean initial bond strength was significantly higher than the mean rebond strength in group 1 but there was no significant difference between the two in the other three groups. Failures at the bracket-adhesive interface occurred frequently at second debonding in group 1. Under the SEM, residual adhesive was removed from the bracket bases by Er,Cr:YSGG laser, while adhesive remnant was seen underneath the meshwork of the bracket bases and microroughness appeared on the meshwork after sandblasting. Er,Cr:YSGG laser certainly could serve the purpose of promoting the use of recycled orthodontic brackets.
authors.affiliation: Orthodontic Dentistry, The Nippon Dental University Niigata Hospital, 1-8 Hamaura-cho, Chuo-ku, Niigata, 951-8580, Japan. ishikatu@ngt.ndu.ac.jp
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Ishida
authors.forename: Toshiya
authors.initials: T
authors.lastname: Endo
authors.forename: Koichi
authors.initials: K
authors.lastname: Shinkai
authors.forename: Yoshiroh
authors.initials: Y
authors.lastname: Katoh
mesh_terms: D000268:Adhesiveness; D000537:Aluminum Oxide / Q000737:chemistry; D055117:Curing Lights, Dental / Q000145:classification; D001840:Dental Bonding; D017005:Dental Debonding / Q000295:instrumentation*; D045662:Dental Etching / Q000379:methods; D003799:Dental Stress Analysis / Q000295:instrumentation; D004868:Equipment Failure; D017743:Equipment Reuse; D006801:Humans; D053844:Lasers, Solid-State; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D019279:Resin Cements / Q000737:chemistry / Q000528:radiation effects*; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D019279:Resin Cements; C429625:Transbond Plus Self-Etching Primer; C477790:Transbond XT; D000537:Aluminum Oxide