The effect of enamel bleaching on the shear bond strengths of metal and ceramic brackets.
The aim of this study was to evaluate the effects of bleaching and delayed bonding on the shear bond strengths of metal and ceramic brackets bonded with light and chemically cure composite resin to human enamel. One hundred and twenty extracted human premolar teeth were randomly divided into three groups of 40 each. The first two groups were bleached with 20 per cent carbamide peroxide (CP) at-home bleaching agent. No bleaching procedures were applied to the third group and served as control. The first two and control groups were divided into equal subgroups according to different adhesive-bracket combinations. Specimens in group 1 (n = 40) were bonded 24 hours after bleaching process was completed while the specimens in group 2 (n = 40) were bonded 14 days after. The specimens in all groups were debonded with a Universal testing machine while the modified adhesive remnant index was used to evaluate fracture properties. No statistically significant differences were found between the shear bond strengths of metal and ceramic brackets bonded to bleached enamel after 24 hours, 14 days, and unbleached enamel with light or chemical cure adhesives (P > 0.05). The mode of failure was mostly at the bracket/adhesive interface and cohesive failures within the resin were also observed. Our findings indicated that at-home bleaching agents that contain 20 per cent CP did not significantly affect the shear bond strength of metal and ceramic orthodontic brackets to enamel when bonding is performed 24 hours or 14 days after bleaching.
Department of Orthodontics, Faculty of Dentistry, Istanbul University, Capa 34093 Istanbul, Turkey. evrenoztas@yahoo.com
E
E
Oztaş
G
G
Bağdelen
H
H
Kiliçoğlu
H
H
Ulukapi
I
I
Aydin
D000134:Acid Etching, Dental / Q000379:methods; D000268:Adhesiveness; D000537:Aluminum Oxide / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D000077463:Carbamide Peroxide; D002516:Ceramics / Q000737:chemistry*; D003722:Dental Alloys / Q000737:chemistry*; D001840:Dental Bonding; D003743:Dental Enamel / Q000187:drug effects / Q000648:ultrastructure*; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D016910:Orthodontic Brackets; D010545:Peroxides / Q000737:chemistry / Q000494:pharmacology; D019279:Resin Cements / Q000737:chemistry; D055116:Self-Curing of Dental Resins; D033081:Shear Strength; D012822:Silicon Dioxide / Q000737:chemistry; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014073:Tooth Bleaching / Q000379:methods*; D058205:Tooth Bleaching Agents / Q000737:chemistry* / Q000494:pharmacology; D014508:Urea / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology
D003722:Dental Alloys; D010545:Peroxides; D019279:Resin Cements; D058205:Tooth Bleaching Agents; C477790:Transbond XT; D013193:Stainless Steel; D000077463:Carbamide Peroxide; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide; C073908:Unite resin; D014508:Urea; D000537:Aluminum Oxide