Assessment of in vitro methods used to promote adhesive interface degradation: a critical review

One factor that has a great influence on clinical performance of dental restorations is their resistance to degradation. Morphological changes in the structure of tooth-restoration interface aged in the oral environment have been reported. However, even though the in vivo performance is the ultimate testing environment for predicting the behavior of restorations because of the complexity of intraoral conditions, in vitro models such as thermocycling, mechanical loading, pH cycling, and aging of materials in distilled water, NaOCl, and food-simulating solutions may provide important information about the fundamental mechanisms involved in resin-tooth interface degradation. Most recently, the effect of host-derived enzymes and the storage in deproteinizing solutions (such as aqueous NaOCl) on the degradation of resin-dentin bonds has also been described. This review considers the importance of these in vitro methods on bond durability interface in an attempt to understand the behavior of restoratives over time. The first section is focused on the mechanism of in vivo biodegradation, whereas the second looks at studies that have described the influence of water storage, NaOCl storage, host-derived matrix metalloproteinases, thermocycling, mechanical loading, pH cycling, and food-simulating solutions on the degradation of the adhesive interface. It is obvious that these methodologies do not occur separately in the oral cavity, but that each one has a specific importance in the mechanisms of bond degradation.

The in vitro methods used to simulate bond degradation may describe important points related to the clinical performance of restorations. This article evaluates the mechanism of the in vivo biodegradation of adhesive interfaces as well as the influences that various testing methods have on these bonds.