COBRE Phase III Year 5 Pilot: Dentin Biomodification to Prevent Resin-Dentin Bond Degradation

Esthetic tooth-colored restorations have become very popular worldwide. However, resin-dentin bonds are less durable than resin-enamel bonds, because dentin bonding relies on the modification of organic components. The average replacement time of these restorations is only 5.7 years due to secondary caries that is mainly attributed to failure of resin-dentin bonds. Replacing defective restorations annually has been estimated to cost approximately five billion dollars in the US, not to mention the innumerable loss of additional tooth structure during the restoration replacement. Incomplete penetration of adhesive resin into collagen exposed by acid activates MMPs and cysteine cathepsins which initiates proteolytic degradation and leads to adhesive bond destruction over time. Studies have reported that bond strength loss was approximately 50% up to two years with some dentin adhesives. The degradation mechanisms have been the topic of research in the recent years. However, clinical strategies have not yet been fully explored to assist in the prevention of collagen degradation. Therefore, there is a compelling need to pursue methods to increase the durability of these adhesive restorations. The proposed study will investigate the inhibitory effect of three different dentin pre-treatments on collagen stability by assessing enzymatic degradation, the collagen quality at the resin-dentin interface, and the resin-dentin bond strength. Data from this study will be used as preliminary data for a future project aimed at developing a better bonding material/or protocol to increase the durability of resin-dentin adhesive layer. PI of the prosed study will intend to apply for external findings.