Effect of microwave treatment on the shear bond strength of different types of commercial teeth to acrylic resin.
OBJECTIVE
The purpose of this study was to verify the effect of microwave treatment on the shear bond strength of commercial types of teeth to acrylic resin, when the glossy ridge laps were unmodified (groups 1 and 5), bur abraded (groups 2 and 6), bur grooved (groups 3 and 7) or etched by monomer (groups 4 and 8).


BACKGROUND
Controversial findings have shown that mechanical or chemical changes in ridge-lap surface of the tooth increase or decrease the bond strength between tooth and acrylic resin, and the microwave disinfection may cause different changes on this bond strength.


METHODS
Eighty specimens (n = 10) were made with the acrylic resin bonded to tooth glossy ridge lap, polymerised in water at 74 degrees C for 9 h, and deflasked after flask cooling. Specimens of the groups 5, 6, 7 and 8 were individually immersed in 150 ml of water and submitted to microwave treatment in an oven at 650 W for 3 min. Control specimens (groups 1, 2, 3 and 4) were not microwave treated. Shear bond strength test was performed in an Instron machine with a cross-speed of 1 mm/min. Collected data were submitted to anova and Tukey's test (alpha = 0.05).


RESULTS
Microwave treatment decreased the shear bond strength values of the tooth/resin bond. In the microwaved and non-microwaved procedures, mechanical retention improved the shear bond strength when compared with the control and monomer treatments.


CONCLUSIONS
Shear bond strength of the tooth/resin bond was influenced by the microwave treatment and different commercial teeth association, and was lower for the Biotone tooth.
Consani
Rafael L X
RL
Department of Prosthodontics and Periodontics, Piracicaba Dental School, Campinas State University, Piracicaba, São Paulo, Brazil. rconsani@fop.unicamp.br
Carmignani
Mariana R
MR
Mesquita
Marcelo F
MF
Correr-Sobrinho
Lourenço
L
Guiraldo
Ricardo D
RD
D000180:Acrylic Resins / Q000737:chemistry / Q000528:radiation effects*; D001840:Dental Bonding; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000737:chemistry / Q000528:radiation effects*; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D008422:Materials Testing; D008872:Microwaves; D058105:Polymerization; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014093:Tooth, Artificial; D014867:Water / Q000737:chemistry
D000180:Acrylic Resins; D003764:Dental Materials; D014867:Water