title: The directionality of share adhesive strength between composite resin and dental hard tissue.
abstract: OBJECTIVE
  To inspect the directionality of adhesive strength between composite resins and dental hard tissues.
  
  
  METHODS
  Two kinds of composite resins were bonded with their luting kits to the enamel and dentin surfaces of bovine teeth separately. The dead load shear and impact shear testing were performed from both of root apex direction and cutting edge direction.
  
  
  RESULTS
  The shear adhesive strength between the enamel and two kinds of composite resins was on the same behavior, that the shear adhesive strength of root apex direction was greater than that of cutting edge direction. In the dead load shear testing, the former was about two to three times of the latter (P < 0.05). In the impact shear testing, the former was about three to four times of the latter (P < 0.001). The effect of the direction of acting force was small on the shear adhesive strength between the dentin and two kinds of composite resins. In the both dead load shear testing and impact shear testing, there was no statistically significant difference between the datum of two directional loadings (P > 0.05, P > 0.5).
  
  
  CONCLUSIONS
  The shear adhesive strength between the composite resins and enamel of bovine teeth is related to the acting direction of the shear force.
authors.affiliation: Dental Material Lab., Research Institute of Stomatology, Peking University, Beijing 100081, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Zheng
authors.forename: Tong
authors.initials: T
authors.lastname: Wang
authors.forename: Hengchang
authors.initials: H
authors.lastname: Xu
mesh_terms: D000268:Adhesiveness; D000269:Adhesives / Q000592:standards; D000818:Animals; D002417:Cattle; D003188:Composite Resins / Q000592:standards*; D001840:Dental Bonding; D003743:Dental Enamel; D003804:Dentin; D017220:Dentin-Bonding Agents / Q000592:standards; D008422:Materials Testing / Q000379:methods; D019279:Resin Cements / Q000592:standards*; D033081:Shear Strength
chemical_list: D000269:Adhesives; D003188:Composite Resins; D017220:Dentin-Bonding Agents; D019279:Resin Cements