Restorative Dentistry and Endodontics

The Korean Academy of Conservative Dentistry (대한치과보존학회)
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AN EXPERIMENTAL STUDY ON BOND STRENGTH OF COMPOSITE RESIN TO BLEACHED ENAMEL

표백된 법랑질에 대한 복합레진의 결합강도에 관한 연구

  • Yu, Mi-Kyung (Dept. of Conservative Dentistry, School of Dentistry, Chonbuk National University) ;
  • Lee, Kwang-Won (Dept. of Conservative Dentistry, School of Dentistry, Chonbuk National University) ;
  • Song, Kwang-Yeob (Dept. of Prosthodontics, School of Dentistry, Chonbuk National University) ;
  • Son, Ho-Hyun (Dept. of Conservative Dentistry, School of Dentistry, Chonbuk National University)
  • 유미경 (전북대학교 치과대학 보존학교실) ;
  • 이광원 (전북대학교 치과대학 보존학교실) ;
  • 송광엽 (전북대학교 치과대학 보존학교실) ;
  • 손호현 (전북대학교 치과대학 보존학교실)
  • Published : 1994.03.10
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Abstract

The purpose of this study was to examine the shear bond strength of resin-enamel bond formed at specific time intervals after the termination ov vital bleaching. A total of 72 human extracted maxillary premolars were divided into nine groups : untreated control (group 1) ; enamel treated with 35% hydrogen peroxide(group 2, 3, 4, 5) ; and enamel reated with 15% carbamide peroxide gel (group 6, 7, 8, 9). After the treatment with 35% hydrogen peroxide for 2 hours and 15% carbamide peroxide for 24 hours, adhesion of a resin to bleached enamel was formed at 1 hour (group 2, 6) and 24 hours(group 3, 7) ; 3days(group 4, 8) and 7 days(group 5, 9) post-termination of bleaching treatment. A $3{\times}3mm$ mold was filled with Scotchbond Multi-Purpose and Z100. After 24 hours later, the specimens were shear-tested at crosshead speed 1mm/min and analyzed statistically. Fractured specimens from group 1,2, 6 were gold-coated with Eiko ion coater and observed under Scanning electron microscope at 25KV. The following results results were obtained : 1. Bonds formed at 1 hour post-termination of 35 % hydrogen peroxide(P<0.01) and 15 % carbamide peroxide bleaching treatment groups(P<0.05) showed significantly lower shear bond strength than untreated group. 2. Bonds formed at 24 hours, 3 days and 7 days post-termination of 35% hydrogen peroxide and 15 % carbamide peroxide bleaching treatment groups showed no significant differences in shear bond strength with untreated group(p>0.05). 3. SEM examinations of the untreated fracture specimen indicated cohesive fracture within enamel and exposed enamel prisms, but the bleached fracture specimens indicated adhesive fracture.

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