Roughness of reline resin after microwave disinfection: a clinical evaluation

Objective: The purpose of this study was to evaluate the effect of microwave disinfection on the surface roughness of hard chairside reline resin after 1-month service period. Methods: Twenty adult patients, 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=10) 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 for 3min at 650W. Roughness measurements were made using Mitutoyo Surftest SJ-400 and the arithmetic roughness values (Ra) obtained were used for comparisons. Each relined denture was subjected to base line evaluation immediately after relining and after 7, 15 and 30 days. Data were analyzed by ANOVA and Kruskal-Wallis followed by Tukey's test (P=0.05). Results: The reline material exhibited roughness values from 2.04 to 2.76Ra. The results demonstrated that, after 15 and 30 days of assessment, the values roughness of DG were significantly lower than those of CG (P<0.05). When comparing the results of the CG, it can be seen that the roughness mean values were not significantly different after relining, 7, 15 or 30 days of use of the complete denture (P>0.05). The results also revealed that no significant differences were found among the periods of use of relined denture for DG (P>0.05). Conclusion: The surface roughness of Tokuyama Rebase II did not affect after 30 days observation period. The microwave disinfection produced a decreased roughness for the tested material.

Grant: FAPESP-05/02194-0