title: Biodegradation of resin-dentin interfaces increases bacterial microleakage.
abstract: Bis-GMA-containing resin composites and adhesives undergo biodegradation by human-saliva-derived esterases, yielding Bis-hydroxy-propoxy-phenyl-propane (Bis-HPPP). The hypothesis of this study is that the exposure of dental restorations to saliva-like esterase activities accelerates marginal bacterial microleakage. Resin composites (Scotchbond, Z250, 3M) bonded to human dentin were incubated in either buffer or dual-esterase media (pseudocholinesterase/cholesterol-esterase; PCE+CE), with activity levels simulating those of human saliva, for up to 90 days. Incubation solutions were analyzed for Bis-HPPP by high-performance liquid chromatography. Post-incubation, specimens were suspended in a chemostat-based biofilm fermentor cultivating Streptococcus mutans NG8, a primary species associated with dental caries, for 7 days. Bacterial microleakage was assessed by confocal laser scanning microscopy. Bis-HPPP production and depth and spatial volume of bacterial cell penetration within the interface increased with incubation time and were higher for 30- and 90-day PCE+CE vs. buffer-incubated groups, suggesting that biodegradation can contribute to the formation of recurrent decay.
authors.affiliation: Biomaterials Discipline, Dental Research Institute, Faculty of Dentistry, University of Toronto, 124 Edward Street, Toronto, ON, Canada M5G 1G6.
authors.forename: S
authors.initials: S
authors.lastname: Kermanshahi
authors.forename: J P
authors.initials: JP
authors.lastname: Santerre
authors.forename: D G
authors.initials: DG
authors.lastname: Cvitkovitch
authors.forename: Y
authors.initials: Y
authors.lastname: Finer
mesh_terms: D000704:Analysis of Variance; D001711:Biotransformation; D017438:Bisphenol A-Glycidyl Methacrylate / Q000493:pharmacokinetics*; D002091:Butyrylcholinesterase / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003188:Composite Resins / Q000493:pharmacokinetics; D003763:Dental Leakage; D003804:Dentin / Q000378:metabolism; D017220:Dentin-Bonding Agents / Q000493:pharmacokinetics*; D006801:Humans; D006868:Hydrolysis; D008422:Materials Testing; D018613:Microscopy, Confocal; D011407:Propane / Q000031:analogs & derivatives / Q000378:metabolism; D019279:Resin Cements / Q000493:pharmacokinetics*; D012463:Saliva / Q000201:enzymology*; D018709:Statistics, Nonparametric; D002787:Sterol Esterase / Q000378:metabolism; D013295:Streptococcus mutans / Q000502:physiology
chemical_list: C422413:2,2-bis(4-(2,3-dihydroxypropoxy)phenyl)propane; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C444701:Filtek Z250; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; D017438:Bisphenol A-Glycidyl Methacrylate; D002787:Sterol Esterase; D002091:Butyrylcholinesterase; D011407:Propane