Curing efficiency of four self-etching,self-adhesive resin cements

ObjectivesTo evaluate the degree of cure (%DC) of four self-etching, self-adhesive resin cements, and one conventional resin cement, in their self- and dual-curing mode.MethodsThe self-etching, self-adhesive resin cements studied were RelyX? Unicem (3M? ESPE? AG), Maxcem? (Kerr Corporation), Biscem? (Bisco, Inc.) and Multilink^® Sprint (Ivoclar Vivadent^® AG) and the classic resin cement was Multilink^® Automix (Ivoclar Vivadent^® AG). Twelve specimens of each material (1.8 mm × 4 mm × 4 mm) were prepared in room temperature (23 ± 1) °C following the manufacturers’ instructions. Six of them were treated as dual-cured, thus irradiated for 20 s with a halogen light curing unit and left undisturbed for 5 min. The other six were treated as self-cured and were not irradiated, but left in dark and dry conditions for 10 min. The assessment of the %DC was made using micro-ATR FTIR spectrometry.ResultsThe %DC in their self-curing mode was very low (10.82–24.93%), with Multilink Sprint exhibiting the highest values among the five. In the dual-curing mode the values obtained were also low (26.40–41.52%), with the exception of Multilink Automix (61.36%). Maxcem was found to have the lowest DC.SignificanceThe low %DC found raises questions as to whether these materials can be successfully used in clinical applications, where light attenuation takes place. Increased irradiation times could potentially lead to higher %DC, in applications where light is not completely blocked by the overlying restoration.