Evaluation of efficiency of manual polishing over autoglazed and overglazed porcelain and its effect on plaque accumulation

PURPOSE: The aim of this study was to evaluate the efficiency of manual polishing over autoglazed and overglazed porcelain and their effect on plaque accumulation. MATERIALS AND METHODS: Thirty-six porcelain discs were fabricated out of which 18 each was subjected for autoglazing and overglazing. Half surface of the discs was left intact; the remaining half was roughened with medium grit diamond bur. Roughened surfaces were repolished by porcelain polishing kits (Shofu, DFS, Eve). All the surfaces were evaluated by the perthometer and SEM. Six discs from each sample were placed in human volunteer's mouth for 72 hours to evaluate the plaque accumulation. Acquired data was subjected to ANOVA comparative evaluation. RESULTS: Roughened surfaces had average roughness value of 2.88+/-0.1935 microm. The repolished surfaces by porcelain correction kits Shofu, DFS and Eve, average roughness value reduced to 0.6250+/-0.1036, 0.9192+/-0.0953, 0.9017+/-0.1305 respectively. Autoglazed and overglazed surfaces showed the mean roughness value (Ra) of 0.4217+/-0.0685, 0.3450+/-0.0729. SEM study showed the improved surfaces when subjected for polishing. Plaque accumulation percentage was the highest on roughened surface (93.83+/-6.2552%), followed by porcelain discs polished by commercial kits. Autoglazed surfaces found to be the best surfaces with the least plaque accumulation (0.5237+/-0.4209%). CONCLUSION: All the polishing kits used in the study reduced the average roughness by approximately 77%. Corrected porcelain surfaces should ideally be reglazed, alternatively, polish the surfaces before final cementation.

Effect of alginate chemical disinfection on bacterial count over gypsum cast

PURPOSE: To evaluate the efficacy of sodium hypochlorite (1 : 10) and iodophor disinfectants on alginate impressions along with their effect on the survived bacterium count on the gypsum cast. MATERIALS AND METHODS: Four alginate impression on each dentate patients were made, of which Group I were not washed or disinfected, Group II impressions were merely washed with water, Group III were disinfected by spraying with sodium hypochlorite (1 : 10), Group IV were disinfected with iodophor (1 : 213). Gypsum cast (type III) were made from all the impression. Impressions and gypsum cast were swabbed in mid palatal region for bacterial culture. Bacterial colony counting done after 3 days of incubation at 37degrees C in blood agar media. The data obtained was analyzed by one way ANOVA test at a significant difference level of 0.05. RESULTS: Group I and Group II showed significantly more bacteria compared to Group III and Group IV. Bacterial colonies on the alginate impression and gypsum cast in group disinfected with Sodium hypochlorite (1 : 10) were 0.18, 0.82 respectively compared to group treated with iodophor (1 : 213). There was an increase in bacterial count on dental cast compared to source alginate impressions. CONCLUSION: Sodium hypochlorite (1 : 10) was found to be better disinfectant for alginate impression. There was an indication of increase in number of bacteria from alginate impression to making of dental cast. Additional gypsum cast disinfectant procedures need to be encouraged to completely eliminate cross infection to dental laboratory.