The combination of casting alloys and resin is common in the fabrication of dental prostheses. Classically, the attachment of resins to casting alloys has been accomplished by mechanical retention. During intraoral function, dental prostheses are subjected to an inordinate load and thermal cycling. These factors, individually or in combination, can exceed the mechanical retention, causing separation at the resin - metal interface.
During the last decate, new adhesive systems have been developed for creating chemical retention of polymers materials to dental alloys. These systems improves resistance to separation and ensures greater longevity of the prosthesis.
The purpose of this study was to evaluate the bonding ability of one of these systems, the silicoater MD - Dentocolor system on dental alloys in comparison with conventional retention bends.
Three dental alloys were used: Wiron 99 (Ni - Cr, Bego Co.), Wirolloy (Ni - Cr, Bego Co.) and Wirobond C (Co - Cr, Bego Co.). The bond strengths between resin and metal were determined by use of the four - point flexure bond test (4 FPBT). Before this, all the samples were subjected to a thermocycling program that included 1500 thermal cycles between 5°C - 55 aC.
This study indicated that the silicoater MD - Dentacolor system can provide stable bonding of resin to metal substructures despite prolonged wet storage and intensive thennocycling. This system can also be used clinically retentive configurations on metal frameworks, resulting in better esthetics.