Bonding to caries-affected dentin: a systematic review

Abstract

BACKGROUND: ‘Minimal invasive dentistry’ aims at preserving the firm, discoloured caries-affected dentin (CAD), which is remineralizable and free of bacteria. The research studies of dental adhesives are usually performed on sound dentin (SD), though CAD is the substrate commonly encountered for bonding in routine clinical practice. AIM: To systematically analyze the published literature on resindentin bonding to CAD substrate, in order to answer the question: ‘Does resin adhesive bonding to CAD produce weaker bonds when compared to SD?’ DESIGN: Electronic databases were searched to identify original studies that evaluated the bond achieved between adhesive resin and CAD by measuring their bond strength (BS). Full text articles in English language were only included. Further relevant articles from the reference list of the retrieved studies were accessed through further electronic and hand searches. Only articles that met the specific inclusion criteria were included in the review. RESULTS: Among the 34 studies included for this review, over 80% of them had used micro-tensile test for BS measurement, whilst <20% used micro-shear test method. Majority of the studies had tested the simplified etch-and-rinse or self-etch adhesives. Eighty-percent of them showed higher BS to SD compared to CAD and the remaining 20% of them showed no difference between these two substrates. Among the studies that used three-step etch-and-rinse adhesives, 40% showed higher and 60% showed no difference when BS was compared between SD and CAD. CONCLUSION: Simplified resin adhesives produce weaker bonds to caries-affected dentin than sound dentin.