Current literature does not provide adequate descriptions of the long-term adhesive characteristics of dentin bonding agents. Laboratory and clinical evidence point to loss of bond integrity over time, however the degradative mechanisms are not understood. Objective: This study was designed to describe the interfacial ultrastructure of the resin-dentin interface, after storage in PBS and collagenase as hydrolytic and enzymatic challenges, using transmission electron microscopy (TEM). Materials and Methods: Scotchbond Multi-Purpose, a total-etch 3-step adhesive resin and Z-100 resin composite (3M ESPE) were used to form a composite crowns on flattened occlusal dentin. 24 hours after bonding sectioning was accomplished to obtain multiple sticks for storage in either PBS or 0.1% collagenase up to 15 months at 37°C. These samples along with 24 hour controls were processed by standard electron microscopy techniques followed by staining with PTA/UA before TEM evaluation. Results: After 15-month storage both PBS and collagenase showed evidence of interfacial degradation, whereas the control group demonstrated even staining and collagen banding throughout. Lack of collagen banding was more evident in collagenase storage as compared to PBS. Conclusion: These morphologic differences observed under the described storage conditions support the theory that collagen denaturation may degrade resin-dentin bond integrity. Experimentation to date cannot rule out the possibility of concurrent adhesive resin breakdown, and is being investigated. Supported by NIDCR/NIH T35 DE07159-18.

Back to the Dental Materials: II - Adhesion-Other Program
Back to the 32nd Annual Meeting and Exhibition of the AADR (March 12-15, 2003)

Top Level Search