title: Effect of repeated microwave disinfections on bonding of different commercial teeth to resin denture base.
abstract: OBJECTIVE
  To verify the influence of repeated microwave disinfections on the shear bond strength of two commercial types of teeth to acrylic resin, when the ridge lap surfaces were unmodified, bur abraded, bur grooved or etched by monomer.
  
  
  METHODS
  Eighty specimens (n = 10) were adhered to the tooth ridge lap surface, polymerised in a water bath at 74°C for 9 h. Microwaved specimens were individually immersed in 150 ml of water and submitted to five simulated disinfections in a microwave oven calibrated at 650 W for 3 min. Control specimens were not microwave treated. Shear bond strength tests were performed in an Instron machine with a cross-speed of 1 mm/min. The fracture load values were transformed into shear bond strength as a function of the bonding area (0.28 cm(2)). Data were submitted to ANOVA and Tukey's test (α = 0.05). Fractured areas were classified as adhesive, cohesive (resin or tooth) or mixed failures.
  
  
  RESULTS
  Repeated microwave disinfections increased the shear strength of the tooth/resin bond. Mechanical retention in microwaved and non-microwaved procedures improved the shear bond strength.
  
  
  CONCLUSIONS
  The different commercial types of teeth influenced shear bond strength values, with Biotone teeth showing the lower values.
authors.affiliation: Department of Prosthodontics and Periodontics, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil. rconsani@fop.unicamp.br
authors.forename: Rafael L X
authors.initials: RL
authors.lastname: Consani
authors.forename: Tatiane
authors.initials: T
authors.lastname: Soave
authors.forename: Marcelo F
authors.initials: MF
authors.lastname: Mesquita
authors.forename: Mario A C
authors.initials: MA
authors.lastname: Sinhoreti
authors.forename: Wilson B
authors.initials: WB
authors.lastname: Mendes
authors.forename: Ricardo D
authors.initials: RD
authors.lastname: Guiraldo
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000180:Acrylic Resins / Q000737:chemistry / Q000528:radiation effects*; D000268:Adhesiveness; D001840:Dental Bonding; D045662:Dental Etching / Q000295:instrumentation; D003764:Dental Materials / Q000737:chemistry / Q000528:radiation effects*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003819:Denture Bases; D004203:Disinfection / Q000379:methods*; D006801:Humans; D008422:Materials Testing; D008872:Microwaves / Q000627:therapeutic use*; D063225:Organically Modified Ceramics / Q000737:chemistry / Q000528:radiation effects; D058105:Polymerization; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014093:Tooth, Artificial; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D003764:Dental Materials; D063225:Organically Modified Ceramics; D014867:Water