Abstract:

Introduction . Tooth-colored resin fillings have become increasingly popular as restorative materials. This increase makes it important to differentiate among the materials for forensic and biological purposes. For the forensic aspect, prior studies were done concerning the inorganic portion of the dental restorative composite resins' composition and succeeded to characterize the composite resin brands into similar and different groups to aid in their discrimination. No prior studies were done to test the ability to differentiate the organic part of dental composite resins. Many studies were also done to differentiate the cytotoxic effects of composite resins to other restorative dental materials but no studies were done to find out if different composite resin brands would have different cytotoxicity to cells in the proximal vicinity.

Materials and methods . Fourteen commercially available composite resin brands selected from the list of materials used in the previous studies of the inorganic part were used in the study. MAIR-IR Spectroscopic analysis was used for surface characterization of the covalently bonded organic and inorganic parts of the composite resin samples. All of the methods were following the methods used in a previous pilot study done on another 3 different dental restorative materials. The composite resin samples were studied As-Is and after 2 weeks saline incubation. IR Spectroscopy was also done on the saline extracts to find out if different composite resin materials would have different leaching abilities. The saline extracts were also used for the viability testing of HGF cell cultures in 50 and 100?l doses added to the cell cultures in separate settings. One way ANOVA analysis of variance was the test statistics used to analyze the results.

Results . It was found that the composite resin brands have different spectra after saline soaking which might indicate that IR spectroscopy can be a useful tool for discrimination between composite resin restorations "after saline soaking" to serve the forensic aspect. It was also found that these composite resin brands possess different leaching abilities in regard to the amount and type of materials. They also have different cytotoxic effects which were found to be threshold dependent.

Conclusion . IR spectroscopy might be considered a useful tool for dental composite resins' covalently bonded organic and inorganic part characterization. These resins have different leaching abilities and cytotoxicity. However, more oral simulating environmental testing methods, different surface characterization methods and more cell viability testing methods and assays must be considered for more specific results.