Bonding procedures for intraoral repair of exposed metal with resin composite.
OBJECTIVE
To determine if tin plating can be recommended for intraoral repair of ceramic veneered cast restorations where metal of unknown composition is exposed by loss of ceramic. This study investigated the effectiveness of surface treatments incorporating tin plating and unfilled resin to enhance the tensile bond strength of a resin composite restorative to three different metal ceramic casting alloys.


METHODS
Gold-platinum, palladium-tin and nickel-chromium alloys were used to fabricate 120 rods of each alloy, 4 x 15 mm. The end of each rod was ground perpendicular on 600-grit SiC paper and grit blasted with 50-micron alumina. Rods from each alloy were divided into four groups of 30 to receive one of the following treatments before bonding pairs end to end with a visible light-polymerized resin composite (Herculite XRV): 1) direct bonding with the resin composite; 2) tin plating (Micro-Tin) and bonding; 3) application of unfilled resin (Chameleon) and bonding; 4) tin plated, application of unfilled resin and bonding. The bonded samples were stored in distilled water, incubated at 37 degrees C for 24 hours and tested for tensile bond strength at a crosshead speed of 1 mm/min in a Lloyd 1000R machine. The mode of failure was examined using a stereo zoom microscope.


RESULTS
A statistically significant increase in tensile bond strength was demonstrated between the control (group 1) and both the gold and palladium alloy treated with tin plating and unfilled resin (group 4). Tin plating, or tin plating with the application of unfilled resin had no statistically significant effect on the tensile bond strength of resin composite to the nickel-chromium alloy.


CONCLUSIONS
The results demonstrate that tin plating, in conjunction with the application of a low-viscosity unfilled resin, optimizes the tensile bond of a resin composite to the three alloys used in the study. This procedure can be recommended for intraoral repair of exposed metal when the type of alloy belongs to one of the investigated alloy groups.
Kiatsirirote
K
K
Department of Restorative Dentistry, University of Sheffield, Claremont Crescent, Sheffield S10 2TA, UK.
Northeast
S E
SE
van Noort
R
R
D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate; D002858:Chromium Alloys; D003188:Composite Resins; D001840:Dental Bonding / Q000379:methods*; D017269:Dental Prosthesis Repair / Q000379:methods*; D004595:Electroplating; D006047:Gold Alloys; D008422:Materials Testing; D016876:Metal Ceramic Alloys; D010165:Palladium; D019095:Point-of-Care Systems; D019279:Resin Cements; D018709:Statistics, Nonparametric; D013718:Tensile Strength; D014001:Tin
D002858:Chromium Alloys; D003188:Composite Resins; D006047:Gold Alloys; D016876:Metal Ceramic Alloys; D019279:Resin Cements; C065770:Herculite XR; D017438:Bisphenol A-Glycidyl Methacrylate; D010165:Palladium; D014001:Tin