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Background Candida biofilm is a major cause of denture stomatitis. We aimed to compare the efficacy of low‐molecular‐weight chitosan solutions against Candida albicans biofilm on polymethyl methacrylate (PMMA) resin. Methods Various types of chitosan were tested for anti‐Candida activity by broth dilution. Two types were selected for further testing on 24‐hour C.albicans biofilm formed on PMMA specimens. Specimens were randomly distributed among experimental groups, including 0.1% and 0.2% acetic acid, 3 and 6 mg/mL of oligomer chitosan and 30 kDa chitosan solutions, effervescent tablet (Polident), and 0.2% chlorhexidine, and immersed for 5 min to 12 h. The viability of C. albicans after cleansing were determined by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assays. Remaining viability was calculated into percentage relative to respective controls and analyzed using ANOVA with Tukey post‐hoc tests. Live/dead fluorescence microscopy was also performed. Results Chitosan solutions had high efficacy against C. albicans biofilm on PMMA. The mean relative viability compared to control after 12‐h immersion was 6.60 ± 4.75% and 12.72 ± 6.96% for 3 and 6 mg/mL oligomer, respectively, and 11.68 ± 4.81% and 18.08 ± 6.20% for 3 and 6 mg/mL 30 kDa chitosan, respectively. Conclusions Low‐molecular‐weight chitosan solution is an effective antifungal denture cleanser that can significantly reduce C. albicans viability in biofilm on PMMA.

This study investigated the shear bond strength (SBS) between veneering porcelain and zirconia substructure using lithium disilicate glass-ceramic as a liner. The mineral phases and microstructures of lithium disilicate glass-ceramic at temperature range of 800-900°C were preliminarily investigated. SBSs of porcelain-veneered zirconia specimens with and without lithium disilicate glassceramic liner fired at the same temperature were determined. Results showed that SBSs of veneering porcelain and zirconia with lithium disilicate glass-ceramic liner was notably increased (p<0.05). Specimens from the group with the highest SBS (59.7 MPa) were subject to thermocycling up to 10,000 cycles and their post-thermocycling SBSs investigated. Though weakened by thermocycling, SBSs were above the clinically acceptable limit (25 MPa) of ISO 9693. Fractographic analysis revealed mixed cohesive and adhesive failures. It was concluded that lithium disilicate glass-ceramic is a potential liner which generated high SBS between veneering porcelain and zirconia.

The aim was to investigate the relation between micromorphology of porosity and electrical resistance of dental luting cements. Five dental luting cements were evaluated: zinc phosphate, glass ionomer, and three types of resin luting cements. Porosity of the specimen was analyzed by micro-CT and electrical resistance of cement was measured at voltage of 125 V up to 30 days and solubility of each specimen was calculated. It showed that the resin luting cements provided the highest electrical resistance regardless of amount of porosity. Zinc phosphate and glass ionomer had high porosity and the lowest resistance (14 and 3 kΩ, respectively). It was found that the electrical resistance of luting cement was not directly affected by the amount of porosity, but it seems to be related to pore connection. There is no correlation between electrical resistance and percentage of porosity but the morphology of porosity may have an influence on the electrical property of luting cement. Models of pore connection were proposed to explain the electrical resistance of luting cement.