Roughness of reline resin after disinfection: 1-year of clinical evaluation

Objective: This study evaluated the effect of disinfection method on the surface roughness of a hard chairside reline resin after 1-year service period. Methods: Forty adult patients aged between 30 and 75 years, who required denture reline treatment, participated in this study. Tokuyama Rebase II was used to reline complete maxillary dentures. Adaptation of each denture was examined and the surface to be relined was reduced by means of a rotary cutting instrument. The relining material was spatulated, poured into the relining area, inserted and adjusted after setting. The edentulous subjects were randomly divided into 2 groups (n=20) and dentures were cleansed according to two methods: CG (control group)- brushing with coconut soap and soft toothbrush; DG (disinfection group)- brushing according to previous methods and microwave disinfection once a week for 3 min at 650W. Roughness measurements were made using Mitutoyo Surftest SJ-400 and the arithmetic roughness values (Ra) obtained were used for comparisons. Surface roughness was assessed at 7 and 15 days, 1, 3, 6 and 9 months and 1 year post-placement. The data were analyzed by repeated-measures ANOVA and Tukey tests. A 95% confidence level was used. Results: The reline material exhibited mean values of roughness from 1.95 to 2.79Ra. The roughness values obtained after microwave disinfection were statistically lower compared to control group (P<0.05). There were no significant differences between mean values of roughness of periods over the 3 months. Comparison among baseline, 7 days, 15 days and 1 month revealed that there were no significant differences on the surface roughness of evaluated material. Conclusion: Microwave disinfection caused improvement on surface roughness of the reline material. Thus, microwave can be used for the relining denture disinfection.