Assessment of degree of conversion of polymer-based orthodontic adhesive resins

摘要

Degree of conversion (DC) of selected currently used orthodontic adhesive materials, after their polymerization with dental curing light, were investigated in laboratory conditions. Samples of four orthodontic adhesives (Contec LC, Transbond XT, Transbond Plus and Resilience) were prepared in Teflon matrices and then formed into the thickness of 1 mm. After the baseline measurement of cross linking of the materials with Fourier transform infrared spectroscopy (FT-IR) the samples were cured with treatment light, and then 1 and 24 h after the completion of the photopolymerization process, the values of DC were evaluated. The results were analyzed using the Statistica 8.0 software package. In the process of hypothesis testing the level of significance was assumed at alpha = 0.05. The statistical analysis yielded significant differences between DC values of orthodontic adhesives tested in both time periods and a significant increase after 24 h storage of the studied orthodontic adhesive systems. It was stated that DC values of the visible light-cured orthodontic adhesives assessed in the present study depend of the type of the composite material. A significant increase in DC occurring with extended period of observation proves that polymerization of dental adhesive materials is a long-term process.