Conversion Degree of Adhesive Systems Photocured by Different Light Sources

Objectives: This study evaluated the effects of different light sources on degree of conversion (DC) of adhesive systems by Fourier Infrared Analysis (FTIR-Equinox 55–Bruker). Methods: The adhesive systems Single Bond (SB-3M) and Clearfil SE Bond (CF-Kuraray) were applied to KBr pellets and photocured with either halogen light curing unit (HA-XL 3000-3M) or LED (Elipar Freelight 1-3M) for 10 seconds (as recommended by manufacturers'). Spectra of uncured and cured samples were obtained before and immediately (I) after photocuring, as well as 1 week (1w) after storage in distilled water (37ºC) (n=8). DC was calculated by comparing the peaks located at 1609 cm^-1 (internal standard) and 1638 cm^-1 (C=C) from the spectra of uncured and cured samples. The DC results were submitted to two-way split-splot ANOVA and Tukey's test (5%). Results: The DC results of samples photocured by LED immediately after photocuring (SBLED(I):13.50±3.25; CFLED(I):6.14±0.99) were lower than those obtained when HAL was used (SBHA(I):18.73±3.87; CFHA(I):13.57±1.88). DC increased after 1w for both adhesive systems, however DC of samples photocured with LED (SBLED(1w):50.34±4.77; CFLED(1w):49.18±4.49) were lower than the DC of samples photocured with HA (SBHA(1w):51.32±6.66; CFHA(1w):56.46±2.92). Conclusion: DC of both adhesive systems photocured with LED was lower than DC of adhesive photocured with HA, immediately after photocuring and after 1 week of storage in water. FAPESP: 03/03645-0