A major cause for dental resin composite restoration replacement is secondary caries attributed to Streptococcus mutans. Salivary esterases were shown to degrade resin composites. Hypothesis: S. mutans contain esterase activities that degrade dental resin composites and adhesives. Esterase activities of S. mutans were measured using synthetic substrates. Standardized specimens of resin composite (Z250), total-etch (Scotchbond-Multipurpose, SB), and self-etch (Easybond, EB) adhesives were incubated with S. mutans UA159 for up to 30 days. Quantification of a bisphenol-glycidyl-dimethacrylate (BisGMA)-derived biodegradation by-product, bishydroxy-propoxy-phenyl-propane (BisHPPP) was performed using high performance liquid chromatography. Results: S. mutans were shown to contain esterase activities in levels comparable to human saliva. A trend of increasing BisHPPP release throughout the incubation period was observed for all materials and was elevated in the presence of bacteria vs. control for EB and Z250 (p<0.05) but not SB. Conclusion: biodegradation by cariogenic bacteria could compromise the resin-dentin interface and reduce the longevity of the restoration.

A major cause for dental resin composite restoration replacement is secondary caries attributed to Streptococcus mutans. Salivary esterases were shown to degrade resin composites. Hypothesis: S. mutans contain esterase activities that degrade dental resin composites and adhesives. Esterase activities of S. mutans were measured using synthetic substrates. Standardized specimens of resin composite (Z250), total-etch (Scotchbond-Multipurpose, SB), and self-etch (Easybond, EB) adhesives were incubated with S. mutans UA159 for up to 30 days. Quantification of a bisphenol-glycidyl-dimethacrylate (BisGMA)-derived biodegradation by-product, bishydroxy-propoxy-phenyl-propane (BisHPPP) was performed using high performance liquid chromatography. Results: S. mutans were shown to contain esterase activities in levels comparable to human saliva. A trend of increasing BisHPPP release throughout the incubation period was observed for all materials and was elevated in the presence of bacteria vs. control for EB and Z250 (p<0.05) but not SB. Conclusion: biodegradation by cariogenic bacteria could compromise the resin-dentin interface and reduce the longevity of the restoration.

A major cause for dental resin composite restoration replacement is secondary caries attributed to Streptococcus mutans. Salivary esterases were shown to degrade resin composites. Hypothesis: S. mutans contain esterase activities that degrade dental resin composites and adhesives. Esterase activities of S. mutans were measured using synthetic substrates. Standardized specimens of resin composite (Z250), total-etch (Scotchbond-Multipurpose, SB), and self-etch (Easybond, EB) adhesives were incubated with S. mutans UA159 for up to 30 days. Quantification of a bisphenol-glycidyl-dimethacrylate (BisGMA)-derived biodegradation by-product, bishydroxy-propoxy-phenyl-propane (BisHPPP) was performed using high performance liquid chromatography. Results: S. mutans were shown to contain esterase activities in levels comparable to human saliva. A trend of increasing BisHPPP release throughout the incubation period was observed for all materials and was elevated in the presence of bacteria vs. control for EB and Z250 (p<0.05) but not SB. Conclusion: biodegradation by cariogenic bacteria could compromise the resin-dentin interface and reduce the longevity of the restoration.

A major cause for dental resin composite restoration replacement is secondary caries attributed to Streptococcus mutans. Salivary esterases were shown to degrade resin composites. Hypothesis: S. mutans contain esterase activities that degrade dental resin composites and adhesives. Esterase activities of S. mutans were measured using synthetic substrates. Standardized specimens of resin composite (Z250), total-etch (Scotchbond-Multipurpose, SB), and self-etch (Easybond, EB) adhesives were incubated with S. mutans UA159 for up to 30 days. Quantification of a bisphenol-glycidyl-dimethacrylate (BisGMA)-derived biodegradation by-product, bishydroxy-propoxy-phenyl-propane (BisHPPP) was performed using high performance liquid chromatography. Results: S. mutans were shown to contain esterase activities in levels comparable to human saliva. A trend of increasing BisHPPP release throughout the incubation period was observed for all materials and was elevated in the presence of bacteria vs. control for EB and Z250 (p<0.05) but not SB. Conclusion: biodegradation by cariogenic bacteria could compromise the resin-dentin interface and reduce the longevity of the restoration.

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / Objectives: A new technology has been introduced into the field of dental resin composites that professes to enhance light-curing efficiency. Rapid amplified photopolymerization (RAP) initiator technology has not yet been fully compared with resin composites with conventional initiators such as camphorquinone (CQ). The purpose of this study was to compare and contrast the effects of this novel technology (RAP) on properties of two light-cured resin composites. Flowable (EFQ) and microfilled (ESQ) experimental composites were fabricated and supplied from Tokuyama Dental with (w/RAP) and without RAP (w/o RAP). The flexural strength (MPa) and flexural modulus (MPa) were obtained using a three-point bending apparatus (Sintech Renew 1123, Instron Engineering Corp., Canton, MA). Polymerization stress curves were created using a tensometer (American Dental Association Health Foundation, NIST, Gaithersburg, MD) which were then used to calculate the maximum stress rate. Finally, the degree of conversion was measured using infrared spectroscopy (Jassco FT-IR spectrometer, Model: 4100, Jasco Corporation, Tokyo, Japan). When evaluating the flexural strength, the peak stress for EFQ w/RAP was significantly higher than EFQ w/o RAP (p = 0.0001). This was statistically not significant for the ESQ group, even though ESQ w/RAP did have a higher peak stress then ESQ w/o RAP (p = 0.28). The interaction between resin type and RAP was not significant when evaluating the flexural modulus (p = 0.21). Formulations with RAP had a significantly higher flexural modulus then w/o RAP (p = 0.0001). Experimental resins with RAP had significantly higher maximum stress rates than those w/o RAP when evaluating polymerization stress (p = 0.0001). Finally, groups w/ RAP appeared to have a higher degree of conversion than groups without (p = 0.0057). This study showed that the experimental composites with RAP had greater mechanical properties than those without. Unfortunately, the increase in polymerization stress causes concern clinically due to the chance of leakage at the restoration/tooth interface. One of the main potential disadvantages of this new RAP technology is an increase in the polymerization stress. Deciding if this amount of polymerization stress is clinically acceptable is yet to be accomplished.