Effect of denture cleansers on Candida albicans biofilm formation over resilient liners

PURPOSE: The purpose of this study was to analyze the effect of denture cleansers on Candida albicans biofilm formation over resilient liners and to evaluate compatibility between resilient liners and denture cleansers. MATERIALS AND METHODS: Acrylic resin (Lucitone 199(R)) and 3 resilient liners (COE-SOFT(TM), GC RELINE(TM) and SOFRELINER TOUGH TOUGH(R)) were incubated in denture cleansers (Polident(R) and Cleadent(R)) for 8 hours a day and in unstimulated saliva for 16 hours a day (n=25/gp) for 60 days. Two-way and three-way repeated measures ANOVA were performed to compare the surface roughness (Ra), pH and C. albicans binding level by radioisotope (alpha=0.05). The statistical significance of the relation between Ra and adhesion was evaluated by correlation analysis. RESULTS: The degree of Ra was significantly decreased in the following order: COE-SOFT(TM), acrylic resin, GC RELINE(TM) and SOFRELINER TOUGH(R). The immersion in denture cleansers significantly increased Ra of resilient liners, except for SOFRELINER TOUGH(R) in Cleadent(R). No significant differences in pH curves were observed among groups immersed in distilled water and denture cleansers. The binding levels of C. albicans were significantly decreased in the following order: COE-SOFT(TM), GC RELINE(TM), SOFRELINER TOUGH(R), and acrylic resin. The immersion in Cleadent(R) seemed to decrease C. albicans binding level on GC RELINE(TM) and SOFRELINER TOUGH(R). CONCLUSION: Based on the C. albicans binding levels results, it is not recommended to immerse COE-SOFT(TM) in denture cleansers, and GC RELINE(TM) and SOFRELINER TOUGH(R) should be immersed in Cleadent(R).

The effect of denture base surface pretreatments on bond strengths of two long term resilient liners

PURPOSE: Purpose of this study was to evaluate effect of two surface treatments, sandblasting and monomer treatment, on tensile bond strength between two long term resilient liners and poly (methyl methacrylate) denture base resin. MATERIALS AND METHODS: Two resilient liners Super-Soft and Molloplast-B were selected.Sixty acrylic resin (Trevalon) specimens with cross sectional area of 10x10 mm were prepared and divided into two groups of 30 specimens each. Each group was surface treated (n = 10) by sandblasting (250 micro alumina particles), monomer treatment (for 180 sec) and control (no surface treatment). Resilient liners were processed between 2 poly(methyl methacrylate) surfaces, in the dimensions of 10x10x3 mm. Tensile strength was determined with Instron Universal testing machine, at a crosshead speed of 5 mm/min; and the modes of failure (adhesive, cohesive or mixed) were recorded. The data were analyzed using one-way ANOVA, followed by Tukey HSD test (alpha = 0.05). RESULTS: Monomer pretreatment of acrylic resin produced significantly higher bond strengths when compared to sandblasting and control for both resilient liners (P < .001). Sandblasting significantly decreased the bond strength for both the liners when compared to monomer pretreatment and control (P < .001). Mean bond strength of Super-Soft lined specimens was significantly higher than Molloplast-B in various surface treatment groups (P < .05). CONCLUSION: Surface pretreatment of the acrylic resin with monomer prior to resilient liner application is an effective method to increase bond strength between the base and soft liner. Sandblasting, on the contrary, is not recommended as it weakens the bond between the two.