Laboratory evaluation of experimental restorative systems containing 4-META.
OBJECTIVE
To determine the in vitro shear bond strengths and quantitative microleakage of four experimental bonding restorative systems used in conjunction with Metafil-A, an experimental composite that does not contain 4-META, and Metafil-Ex, a 4-META containing experimental composite.


METHODS
120 test specimens were prepared on dentin treated with Amalgambond Activator followed by the application of an experimental primer consisting of 35% glyceryl methacrylate. In 60 teeth the mixed Amalgambond Base and Catalyst was then applied while in the remaining 60 teeth this step was omitted. Cylinders of either Metafil-A or Metafil-Ex were bonded to the dentin surfaces and the test specimens removed from the assembly apparatus after 1 minute or after 15 minutes and the latter specimens were stored in saline at 37 degrees C for 24 hours prior to determining the shear bond strength in an Instron machine at a crosshead speed of 0.5 mm/minute. Sixty Class V preparations were made on the facial surfaces of the roots of extracted human premolars and the preparations restored with the four restorative systems. The quantitative microleakage was determined by a spectrophotometric dye-recovery method.


RESULTS
The shear bond strengths were significantly lower when the 4-META-containing Amalgambond Base and Catalyst were not applied and were unmeasurable when Metafil-A was used as the composite. The quantitative microleakage of the latter system was significantly greater than when the other restorative systems were used.
Hasegawa
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Showa University School of Dentistry, Tokyo, Japan.
Retief
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DH
D000180:Acrylic Resins; D000704:Analysis of Variance; D001641:Bicuspid; D001840:Dental Bonding; D003763:Dental Leakage; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent / Q000379:methods*; D017220:Dentin-Bonding Agents; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates; D008963:Molar; D011140:Polyurethanes
D000180:Acrylic Resins; C070606:Amalgambond; D017220:Dentin-Bonding Agents; C090891:Metafil Ex; D008689:Methacrylates; D011140:Polyurethanes; C029824:urethane dimethacrylate luting resin; C090890:Metafil A; C031172:4-META resin; C028643:trimethylolpropane trimethacrylate