The effect of immersion cleansers on gloss, colour and sorption of acetal denture base material.

OBJECTIVE: To study the effect of peroxide and hypochlorite cleansers on gloss, colour and sorption of acetal denture resins. MATERIALS AND METHODS: Pink acetal and thermoplastic acrylic resins were evaluated. Thirty-five specimens 39 x 39x 1.8 mm of each resin were prepared. Each group of specimens (n = 7) was then immersed into cleansers for 100 days. Group I immersed in tap water, Group II in Corega Extradent for 5 min, Group III in Corega Extradent for 8 h, Group IV in NitrAdine Seniors for 15 min and Group V in NaOCl 5.25%. Gloss, colour and weight measurements were taken initially and after 100 days. Data subjected to two-way anova and Tukey's test at alpha = 0.05. RESULTS: Acrylic resin showed reductions of glossiness from -5 to -15 and acetal from -0.2 to -6. Colour changes (DeltaEpsilon*) ranged from 2.64 to 7.64 for acrylic and 2.77 to 26.54 for acetal resin. Sorption for acrylic ranged from 11.64 to 17.06 mug/mm(3) and 9.18 to 24.79 mug/mm(3) for acetal resin. The results of (DeltaEpsilon*) and sorption showed an interaction between denture resins and cleansers. CONCLUSIONS: The gloss of acetal resin was less affected by water, peroxides and NaOCl 5.25% compared with acrylic resin. Acetal resin showed clinically acceptable (DeltaEpsilon*) whereas acrylic resin unacceptable ones for water and peroxide solutions. The immersion of acetal resin in NaOCl 5.25% showed clinically unacceptable (DeltaEpsilon*) and higher sorption and should be avoided or should be managed with care.