Properties of 2,3-butanedione and 1-phenyl-1,2-propanedione as new photosensitizers for visible light cured dental resin composites

Abstract

Two 1,2-diketones, 1-phenyl-1,2-propanedione (PD) and 2,3-butanedione (BD) were investigated as new visible light photosensitizers for formulating a dental resin composite of bis-GMA in order to improve the physical properties of the resin composite. The results were then compared with those of camphorquinone (CQ), the most widely used photosensitizer. Photodecomposition of the photosensitizers with and without amine was studied through UV absorption spectroscopy. The photopolymerization efficiency of bis-GMA containing the photosensitizer increased with irradiation time and with the amount of photosensitizer. The increase was in the order: BD<CQ<PD. The experimental resin composite of bis-GMA containing BD or PD showed better mechanical properties than that which contained CQ. The reason for the higher mechanical properties of the resin composite containing BD or PD as compared with that containing CQ is discussed through the study of a model reaction. It was observed that BD or PD serves not only as a photosensitizer but also as a crosslinking agent.