Clinical evaluation of two materials in the restoration of abfraction lesions

Aim: To evaluate the clinical performance of a composite resin (CR) and a resin-modified glassionomer cement (RMGIC) for the treatment of abfraction lesions. Methods: Thirty patients with abfraction lesions in at least two premolar teeth were selected and invited to participate in this study. All restorations were made within the same clinical time frame. One tooth was restored with CR Z100TM (3M, St. Paul, MN, USA), and the other was restored with RMGIC VitremerTM (3M). The restorations were assessed immediately and 1, 6 and 12 months after the restoration, using modified US Public Health Service (USPHS) criteria: marginal integrity, marginal discoloration, wear, retention, secondary caries and hypersensitivity. The statistical analysis was based on Friedman ANOVA test and Mann-Whitney test, considering p<0.05 for statistical significance. Results: Both materials demonstrated satisfactory clinical performance after one year. In the individual analysis of each material, there was a significant difference (p<0.05) in the criteria marginal integrity and wear, for both CR and RMGIC. RMGIC exhibited more damage one year after the restoration. Comparing both materials, it was found a significant difference only for marginal discoloration, while the RMGIC restorations showed the worst prognosis after a year of evaluation. There was no significant difference in the number of retentions, caries or hypersensitivity between CR and RMGIC. Conclusions: It was concluded that CR exhibited the best clinical performance according to the cost-effectiveness and evaluation criteria used in this study.

Influence of ultrasonic activation in association with different final irrigants on intracanal smear layer removal

Aim: To evaluate the influence of ultrasonic activation (US) with different irrigant regimens in smear layer removal. Methods: One hundred bovine incisors were instrumented and divided into ten groups (n=10) according to final irrigation protocols: distilled water (DW); DW+US; 17% EDTA; QMix; 10% citric acid; 37% phosphoric acid; 17% EDTA+US; QMix+US; 10% citric acid+US; 37% phosphoric acid+US. The samples were then submitted to scanning electron microscopy where a score system was used to evaluate the images and effectiveness of proposed treatments. The data were statistically analyzed by Kruskal-Wallis and Mann-Whitney U tests for intergroup comparisons as well as the Wilcoxon and Friedman tests for intragroup comparisons at 5% significance level. Results: In the cervical third, groups 17% EDTA, QMix, 10% citric acid, 17% EDTA+US, QMix+US and 10% citric acid+US were more effective in smear layer removal (p<0.05); in the middle third, groups 17% EDTA+US and QMix+US were more effective in smear layer removal (p<0.05); in the apical third, groups 17% EDTA,17% EDTA+US and QMix+US were more effective in smear layer removal (p<0.05). Conclusions: US can aid 17% EDTA and QMix in smear layer removal at the middle third and QMix at the apical third, contributing to the cleaning of root canal system.