Novel hydrogen donors as alternative Co-initiators in model dental resins: A performance analysis.

Abstract

This study evaluated the influence of novel co-initiators on the chemical and physical properties of model dental resins at varying initiator-to-co-initiator ratios. A comonomer blend consisting of 50 wt% bis-GMA, 25 wt% TEGDMA, and 25 wt% HEMA was prepared, incorporating 0.5 wt% camphorquinone (CQ) and 0.5 wt% bis(4-methylphenyl)iodonium hexafluorophosphate (IOD). New co-initiators (HD4, HD1, and MHPTm) were tested against standard tertiary amines (DMAEMA and EDAB) at initiator-to-co-initiator ratios of 1:1 and 1:2, resulting in 10 distinct formulations. The properties analyzed included degree of conversion (DC), rate of polymerization (RP), flexural strength (FS), flexural modulus (E), water sorption (Wsp), and solubility (Wsol). Data for DC, FS, E, and Wsp were analyzed using two-way ANOVA and Tukey's test (α = 0.05), and Sol was analyzed with Kruskal-Wallis and Dunn tests (α = 0.05). For the 1:1 ratio, DMAEMA, EDAB, HD4 and MHPTm exhibited statistically higher DC values compared to HD1, while DMAEMA and EDAB showed the highest DC at the 1:2 ratio. Similar trends were noted for RP, FS, and E. For Wsp, DMAEMA and HD4 showed the statistically highest levels, whereas HD4 and HD1 had the highest Sol in the 1:1 formulation. Overall, the 1:2 initiator-to-co-initiator ratio improved the properties of the novel hydrogen donors tested compared to 1:1 ratio. The novel co-initiators demonstrated promising properties for model resins compared to standard references, with the 1:2 ratio yielding the most favorable results for these alternative hydrogen donors.