Can CQ be completely replaced by alternative initiators in dental adhesives?

Abstract

Despite good clinical acceptance, photoinitiating systems based on camphorquinone and amines raise concerns in terms of yellowing, aging, toxicity, or degradation in low pH conditions. This study aimed to prove whether CQ could be successfully replaced by alternative initiators in adhesive systems. Further, the efficiency of a prototype dual-wavelength LED (=Light Emitting Diode) curing unit was analyzed. In two commercial adhesive systems, CQ was completely replaced by Lucirin TPO. The commercial adhesives and their experimental counterparts were evaluated after curing for 10 seconds and 20 second with two dual-wavelength LED units and one regular LED unit, by applying the curing unit on the adhesive surface at two distances of 0 mm and 5 mm. Degree of cure and mechanical properties (Vickers hardness and modulus of elasticity) were assessed after 24-hour storage in distilled water at 37°C. Experimental data showed that the CQ-amine system could be completely replaced by Lucirin TPO when dual-wavelength LED unit was used for photoactivation.