Effect of nano-ceramic coating on surface property and microbial adhesion to poly(methyl methacrylate).

To improve surface properties of poly(methyl methacrylate) (PMMA) using nano-ceramic coatings and assess microbial adherence after long-term use of a chemical cleanser. Thirty-six PMMA samples were fabricated, polished and coated with a nano-thin TiO or mixed TiO /ZrO , with uncoated samples as controls. Six samples in each group (n = 12) were soaked in Polident denture cleaner 180 times for 30 min, while six were soaked in deionized water. Surface roughness of PMMA before and after being soaked in Polident was assessed. All samples were subsequently exposed to Candida albicans for 6 h and the adherent cells were determined by viable colony count. Two-way analysis of variance was performed for statistical analysis. No significant difference in surface roughness was noted between the uncoated and coated PMMA before soaking. After soaking, surface roughness of the uncoated PMMA increased from 0.164 to 0.532 μm (p < .05). No significant change was observed for TiO -coated (0.105-0.143 μm) or TiO /ZrO -coated PMMA (0.104-0.141 μm). Attachment of C. albicans to PMMA soaked in water showed significantly less attachment to both TiO -coated (1.4 × 10 cfu/ml) and TiO /ZrO -coated PMMA (1.6 × 10 cfu/ml) than to the uncoated PMMA (2.6 × 10 cfu/ml). After soaking in Polident, the uncoated PMMA had significantly less C. albicans attachment than coated samples. Less attachment was noted on the TiO /ZrO -coated PMMA then the TiO -coated samples (p < .05). Nano-ceramic TiO2 /ZrO coating of PMMA denture base material alters surface properties thus reduces oral microbial adhesion. It represents a promising alternative to the chemical disinfection for PMMA denture materials.