Light curing unit and restorative material influence on the hardness of a dual cure resin cement

Abstract

This study aimed to investigate the hardness of a dual cure adhesive resin cement (RelyX ARC — 3M ESPE) when polymerized without contact with light and fotoactivated under three different indirect restorative materials (Solidex — Shofu, Empress —Ivoclar, InCeram Alumina system — Vita). Using two types of light curing units: with halogen light (XL 1500 -—3M) and LED — light emtting diode — (UltraLed — Dabi Atlante). Seven experimental groups were created: SH group (Solidex Halogen), SL (Solidex LED), EH (Empress Halogen), EL (Empress LED), TH (inCeram Alumina Halogen), IL (InCeram Alumina LED) and SCL group (without contact with light). Four dual cure adhesive resin cement discs were produced for each group, and fotoactivated for 40 seconds under the indirect restora-tive material, except the SCL group where curing occurred in the absence of light. After one week of storage in 37°C distillated water, the discs were submitted to a microhardness test, in a Shimadzu microdurometer, with 100 grams load for 15 seconds. The results, expressed in Vickers hardness numbers (VHN), were statistically analyzed through ANOVA and Tukey tests, that showed a greater surface hardness of the SH group when compared to the others. SL, EH and EL group were not statistically different between themselves, but had greater values than TH, IL an SCL groups that were also statistically similar between themselves.