title: Effects of ArF excimer laser irradiation of dentin on the tensile bonding strength to composite resin.
abstract: OBJECTIVE
  The purpose of the study was to evaluate the effects of argon fluoride (ArF) excimer laser irradiation on the tensile bonding strength (TBS) of dentin to composite resin.
  
  
  BACKGROUND
  Dental lasers use a photothermal process, which potentially entails risk of tissue damage caused by heat affecting the bond strength of resins. The ArF excimer laser functions by a photochemical process in which the energy of photons directly cuts covalent bonds in molecules without generating heat.
  
  
  METHODS
  Twenty extracted human molars were sectioned perpendicularly to the tooth axis to expose a flat dentin surface. The surfaces were treated with various combinations of ArF excimer laser irradiation, primer treatment, and bonding treatment. After composite resin was built up on the treated dentin surface, specimens with a 1×1 mm bonding interface were prepared and subjected to TBS tests. Treated dentin surfaces were also observed using transmission electron microscopy (TEM).
  
  
  RESULTS
  Specimens that underwent laser irradiation followed by bonding treatment had a TBS that did not differ significantly from that of specimens that received conventional treatment, with or without priming. TEM observations showed sectioned and dispersed collagen matrix in the hybrid layer after laser irradiation, priming, and bonding, but no hybrid layer after laser irradiation and bonding at the treated dentin surface.
  
  
  CONCLUSIONS
  The TBS of conditioning with ArF excimer laser irradiation was identical to that with conventional treatment when bonding was used. The bonding mechanism with the ArF irradiation differed from that of conventional bonding depending upon dentin hybridization.
authors: General Dentistry, Department of Comprehensive Oral Health Care, Division of Comprehensive Patient Care, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
authors: Kazunobu
authors: K
authors: Sano
authors: Ken-Ichi
authors: K
authors: Tonami
authors: Shizuko
authors: S
authors: Ichinose
authors: Kouji
authors: K
authors: Araki
mesh_terms: D003188:Composite Resins / Q000737:chemistry / Q000528:radiation effects*; D003737:Dental Cavity Preparation / Q000379:methods; D003804:Dentin / Q000528:radiation effects*; D017220:Dentin-Bonding Agents / Q000737:chemistry / Q000528:radiation effects*; D006801:Humans; D054018:Lasers, Excimer; D008422:Materials Testing; D013718:Tensile Strength
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents