title: Effect of surface preparation on the failure load of a highly filled composite resin bonded to a denture base resin.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the effect of the surface preparation on the maximum fracture load value of a highly filled gingival shade composite resin bonded to a denture base resin.
  
  
  METHODS
  Block specimens were prepared from a heat-processed denture base resin and divided into five groups. The flat surfaces of the specimens were abraded with 400-grit silicon carbide paper, then prepared in one of the following ways: (1) without preparation (group 1); (2) application of silane coupling agent (group 2); (3) application of dichloromethane (group 3); (4) application of dichloromethane following the silane coupling agent (group 4); or (5) tribochemical silica coating (group 5). A highly filled gingival shade composite resin was applied (area diameter= 5 mm) and polymerized with a light polymerizing unit. Specimens made entirely of heat-processed denture base resin were also fabricated as references (group 6). The halves of the specimens of groups 4, 5, and 6 were thermocycled up to 10,000 times in water between 5 degrees C and 55 degrees C with a 1-minute dwell time at each temperature. Shear testing was performed in a universal testing machine at a crosshead speed of 1 mm/min, and the maximum fracture load values were determined (n = 10).
  
  
  RESULTS
  The maximum fracture load values of the highly filled gingival shade composite resin bonded to the denture base resin for all preparation groups were significantly enhanced before thermocycling (p < 0.05). Group 5 exhibited the greatest fracture load value, followed by group 4, compared to the other groups (p < 0.05), however, the fracture load values significantly decreased for these groups after thermocycling (p < 0.05), whereas the fracture load value of group 6 did not decrease (p > 0.05).
  
  
  CONCLUSIONS
  Tribochemical silica coating and the application of dichloromethane after the silane coupling agent were effective surface preparations for the bonding of a highly filled gingival shade composite resin to a denture base resin, however, the bond durability of these treatments may be insufficient.
authors.affiliation: Division of Removable Prosthodontics, Department of Oral Rehabilitation, Fukuoka Dental College, Fukuoka, Japan. simizuh1@college.fdcnet.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shimizu
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kawaguchi
authors.forename: Kaneyoshi
authors.initials: K
authors.lastname: Yoshida
authors.forename: Fumitake
authors.initials: F
authors.lastname: Tsue
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takahashi
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D017554:Carbon Compounds, Inorganic / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003738:Dental Cements; D045662:Dental Etching; D003764:Dental Materials / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003819:Denture Bases; D006801:Humans; D008422:Materials Testing; D008752:Methylene Chloride / Q000737:chemistry; D019904:Polymethyl Methacrylate / Q000737:chemistry; D033081:Shear Strength; D012821:Silanes / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D017554:Carbon Compounds, Inorganic; D003188:Composite Resins; D003738:Dental Cements; D003764:Dental Materials; C076811:Rocatec; D012821:Silanes; D017655:Silicon Compounds; D014867:Water; D008752:Methylene Chloride; D012822:Silicon Dioxide; D019904:Polymethyl Methacrylate; D000537:Aluminum Oxide; C022088:silicon carbide