Background: Human salivary esterases have been shown to degrade dental resin composite restorations in vivo. Objective: To optimize in vivo protocols to recover biodegradation products and to compare the biostability of urethane-modified-bisGMA- (ubis) and bisGMA-based (bis) commercial resin composites. Methods: Class V and III composite restorations were placed in patients using adhesive and composite resin. Gingival crevicular fluid (GCF), plaque and a 2-minute oral rinse with 20% ethanol in saline (n=10) were collected immediately and 7-days after restoration placement. Samples were analyzed for biodegradation products using high performance liquid chromatography. The oral rinse protocol was then used to compare the bis and ubis composite resins (Z250, 3M; TPH, Dentsply) (n=58). Results and conclusions: The bisGMA composite matrix derived product, bishydroxypropoxyphenylpropane (BisHPPP) was only detected from oral rinse collected immediately after restoration placement. There was no statistical difference in the amount of bisHPPP collected from bis and ubis composite resins. This research was supported by CIHR (MOP 68947).

Background: Human salivary esterases have been shown to degrade dental resin composite restorations in vivo. Objective: To optimize in vivo protocols to recover biodegradation products and to compare the biostability of urethane-modified-bisGMA- (ubis) and bisGMA-based (bis) commercial resin composites. Methods: Class V and III composite restorations were placed in patients using adhesive and composite resin. Gingival crevicular fluid (GCF), plaque and a 2-minute oral rinse with 20% ethanol in saline (n=10) were collected immediately and 7-days after restoration placement. Samples were analyzed for biodegradation products using high performance liquid chromatography. The oral rinse protocol was then used to compare the bis and ubis composite resins (Z250, 3M; TPH, Dentsply) (n=58). Results and conclusions: The bisGMA composite matrix derived product, bishydroxypropoxyphenylpropane (BisHPPP) was only detected from oral rinse collected immediately after restoration placement. There was no statistical difference in the amount of bisHPPP collected from bis and ubis composite resins. This research was supported by CIHR (MOP 68947).