Surface roughness analysis of ceramic systems after disinfection andsterilization procedures

The surface roughness of prosthodontic materials is an important factor that influences the amount of microbial plaque accumulation, thereby increasing the risk of caries and periodontal inflammation of abutment or adjacent teeth. Few studies exist that have investigated the influence of disinfectant materials on the surface roughness of prosthodontic materials. The purpose of this study is to evaluate the roughness changes in metal-ceramic and IPS Empress 2 ceramic structures, finished by either manual-polishing or glazing, followed by immersion in 2% glutaraldehyde solution for either 30 minutes (disinfection procedure) and 10 hours (sterilization procedure). The study consisted of 26 metalceramic specimens and 26 Empress 2 specimens measuring 10 x 10 x 2 mm. One-half of each group of specimens was polished by using rotatory instruments and the other half was glazed in a glazing oven (subgroups). Afterwards, the specimens were submitted to sterilization and disinfection in 2% glutaraldehyde for either 30 minutes or 10 hours, respectively. 3 specimens from each group were sterilized in autoclave, and for control group, the initial measurement of each specimen before the disinfection and sterilization procedures was obtained. The surface roughness was determined by a Hommel Tester T-1000, using the mean arithmetic Ra as roughness parameter. The results were statistically analyzed using a 4-way analysis of variance (ANOVA) method for individual comparisons among the means and the Tukey test at a significance level of p<.05. The results showed that there were no statistically significant differences of roughness in both groups, after immersion in chemical solution and sterilization in autoclave (p<.05). The mean of ceramic materials ranged from .631mm to 1.687mm in surface roughness. There was a statistically significant difference only among final polishing of ceramics (F=19.00; p<.001) and in the interaction between polishing and material used (F=18.83; p<.001). No significant changes in surface roughness of tested ceramic materials occurred after completion of the disinfection and sterilization procedures used in this study. Clinical implications: Infection control procedures are indispensable steps before cementation of prostheses. Based on the results of this study, prosthodontic materials can be disinfected or sterilized without causing significant changes in surface roughness.