Effect of surface preparation using ethyl acetate on the shear bond strength of repair resin to denture base resin.
OBJECTIVE
This study evaluated the effect of using ethyl acetate as a surface preparation agent on the shear bond strength of repair resin to denture base resin.


METHODS
The flat surfaces of a heat-processed denture base resin were prepared with one of the following: (1) without preparation, (2) 60-second application of ethyl acetate, (3) 120-second application of ethyl acetate, (4) 180-second application of ethyl acetate, and (5) 5-second application of dichloromethane. An autopolymerizing repair resin was applied. The specimens were then immersed in 37 degrees C distilled water for 24 hours. The specimens in groups 1, 3, and 5 were thermocycled up to 10,000 times in water between 5 and 55 degrees C with a 1-minute dwell time at each temperature. The shear bond strengths were determined at a crosshead speed of 1.0 mm/min (n = 10). The morphological changes in the repair surfaces after preparation were observed with a scanning electron microscope.


RESULTS
The shear bond strengths of groups 3 and 5 were significantly higher than the other groups before thermocycling (p < 0.05). The shear bond strengths of group 3 were significantly lower than those of group 5 after thermocycling (p < 0.05). The scanning electron microscope (SEM) views showed that the dissolution progressed deeper with the preparation duration.


CONCLUSIONS
The 120-second surface application of ethyl acetate enhanced the shear bond strength between the repair resin and the denture base resin, although the bond durability was inferior to that of the conventional surface preparation.
Division of Removable Prosthodontics, Department of Oral Rehabilitation, Fukuoka Dental College, Japan. simizuh1@college.fdcnet.ac.jp
Hiroshi
H
Shimizu
Masayoshi
M
Kakigi
Junko
J
Fujii
Fumitake
F
Tsue
Yutaka
Y
Takahashi
D000085:Acetates / Q000737:chemistry*; D000180:Acrylic Resins / Q000737:chemistry*; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry*; D003819:Denture Bases; D003780:Denture Repair; D006801:Humans; D008422:Materials Testing; D008752:Methylene Chloride / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D019904:Polymethyl Methacrylate / Q000737:chemistry; D012995:Solubility; D012997:Solvents / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
D000085:Acetates; D000180:Acrylic Resins; D003764:Dental Materials; D012997:Solvents; C112073:unifast II; D014867:Water; D008752:Methylene Chloride; C007650:ethyl acetate; D019904:Polymethyl Methacrylate