Factors affecting the Degree of Conversion of 1 Universal Adhesives

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Rosenthal, Natalie
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Universal adhesives are advertised as having a simplified application technique, however all still require multiple steps. This study tested the effect of solvent evaporation, oxygen inhibition layer (OIL) formation, and curing time on the degree of conversion (DC) for the following dental adhesives: All-Bond Universal Adhesive (AB), Prime & Bond Elect Universal Dental Adhesive (PB), iBond Universal (iBU), Scotchbond Universal (SBU), and One Coat 7.0 (OC). Adhesives were rubbed onto a glass slide for 20 s, then air blown for 5 s or 40 s. Some samples had an Epitex strip (Anaerobic) placed over the adhesive before polymerization, while the other group of samples were cured without an Epitex strip (Aerobic). Samples were light cured for 10 s, 20 s, or 40 s (n=4). The DC was measured using Fourier transmission infrared spectroscopy (FTIR). Results were analysed with 3 way ANOVA and Tukey post-hoc test (α=0.05). Curing under anaerobic conditions significantly increased the overall mean DC for all tested adhesives. A higher DC can be obtained by increasing solvent evaporation time for AB, iBU, SBU, and increasing curing time for all the adhesives, except iBU. Some universal adhesives benefit from a different application process than the manufacturers’ instructions.