title: Effect of Er,Cr:YSGG laser, air abrasion, and silane application on repaired shear bond strength of composites.
abstract: Aged resin composites have a limited number of carbon-carbon double bonds to adhere to a new layer of resin. Study objectives were to 1) evaluate various surface treatments on repaired shear bond strength between aged and new resin composites and 2) to assess the influence of a silane coupling agent after surface treatments.
  
  
  METHODS
  Eighty disk-shape resin composite specimens were fabricated and thermocycled 5000 times prior to surface treatment. Specimens were randomly assigned to one of the three surface treatment groups (n=20): 1) air abrasion with 50-μm aluminum oxide, 2) tribochemical silica coating (CoJet), or 3) Er,Cr:YSGG (erbium, chromium: yttrium-scandium-gallium-garnet) laser or to a no-treatment control group (n=20). Specimens were etched with 35% phosphoric acid, rinsed, and dried. Each group was divided into two subgroups (n=10): A) no silanization and B) with silanization. The adhesive agent was applied and new resin composite was bonded to each conditioned surface. Shear bond strength was evaluated and data analyzed using two-way analysis of variance (ANOVA).
  
  
  RESULTS
  Air abrasion with 50-μm aluminum oxide showed significantly higher repair bond strength than the Er,Cr:YSGG laser and control groups. Air abrasion with 50-μm aluminum oxide was not significantly different from tribochemical silica coating. Tribochemical silica coating had significantly higher repair bond strength than Er,Cr:YSGG laser and the control. Er,Cr:YSGG laser and the control did not have significantly different repair bond strengths. Silanization had no influence on repair bond strength for any of the surface treatment methods.
  
  
  CONCLUSIONS
  Air abrasion with 50-μm aluminum oxide and tribochemical silica followed by the application of bonding agent provided the highest repair shear bond strength values, suggesting that they might be adequate methods to improve the quality of repairs of resin composites.
authors.affiliation: Restorative Dentistry, Indiana University School of Dentistry, Indianapolis, IN 46202, USA. sdhanvar@iupui.edu
authors.forename: S D
authors.initials: SD
authors.lastname: Cho
authors.forename: P
authors.initials: P
authors.lastname: Rajitrangson
authors.forename: B A
authors.initials: BA
authors.lastname: Matis
authors.forename: J A
authors.initials: JA
authors.lastname: Platt
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000180:Acrylic Resins / Q000737:chemistry; D000537:Aluminum Oxide / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D045662:Dental Etching / Q000379:methods*; D058250:Dental Restoration Repair; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D053844:Lasers, Solid-State; D008422:Materials Testing; D010756:Phosphoric Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D012821:Silanes / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors
chemical_list: D000180:Acrylic Resins; D003188:Composite Resins; C451600:OptiBond Solo Plus; D010756:Phosphoric Acids; D019279:Resin Cements; D012821:Silanes; C451741:point 4 composite resin; C030242:phosphoric acid; D000537:Aluminum Oxide