Effect of surface roughness on amalgam repair using adhesive systems

Abstract

The objective of this in vitro study was to evaluate the effect of three surface treatments and two adhesive systems on the shear bond strength of old and freshly placed amalgam. The results suggested that the intact amalgam showed a significantly higher strength than repaired groups and the strongest repaired specimens were made when the amalgam surfaces were roughened with a diamond bur or microetcher. The adhesive systems showed no significant differences on bond strength with the same superficial texture.

Effects of Different Surface Conditioning Methods on the Bond Strength of Composite Resin to Amalgam

“…Opaquers have been advocated to mask the amalgam prior to composite bonding to simulate clinical situations wherein fracture of amalgam involved esthetics, such as in some visible areas of the mouth. 1,3 In this study, one powderliquid opaquer (Sinfony) and three paste opaquers were used. It is likely that bond strengths produced by opaquers, besides being dependent on chemical composition, can depend on consistency and thus handling characteristics.…”

“…The powderliquid opaquer is easier to handle in terms of amount, consistency, and thickness. 1,3 Probably as a result of the thickness of the paste opaquer applied, the deepest part of this layer was not fully polymerized. 13,[16][17][18] On the other hand, a powderliquid opaquer can be easily controlled during application by using the tip of a probe.…”

“…1 As a viable conservative technique, the repair of defective areas has been suggested because it is simple and quick. [1][2][3] Repair also preserves the tooth, as it is difficult to remove a restoration without removing an integral part of the tooth itself. If not necessary, sound enamel and dentin removal is avoided, strength is maintained, and longevity of the tooth is increased.…”

“…If not necessary, sound enamel and dentin removal is avoided, strength is maintained, and longevity of the tooth is increased. 1 Cusp fractures or fractures within amalgam restorations are usually due to impact load, fatigue load during mastication, microdefects in the amalgam, secondary caries, technical errors during cavity preparation, incompatible thermal expansion coefficients, history of endodontic treatment, insufficient sound tooth material available such as undermining cusps, number of surfaces restored, or occlusal prematurity. 2,3 A few reports in the literature describe the incidence of tooth fracture.…”

“…11 Chemical means, on the other hand, use multipurpose adhesive agents. 1,12 Several studies have shown that airborne particle abrasion modifies the metal surface and provides micro-roughness that is essential for mechanical bonding, 1,10,11,13 while primers and adhesives form ionic bonds with metal oxides or with the active metal compounds of the amalgam. 13 However, the existence of a true chemical bond between amalgam and resin composites is controversial.…”