Fluoride Formed on Enamel by Fluoride Varnish or Gel Application: A Randomized Controlled Clinical Trial.

Although fluoride varnish (FV) and acidulated phosphate fluoride gel (APF-gel) are considered clinically effective to reduce caries, in vitro studies have shown that FV reacts slowly with enamel because most NaF present in the formulation is not solubilized in the FV. Therefore, we conducted a clinical study to evaluate if the time that FV remains on dental surfaces could overcome its slower chemical reactivity when compared with APF-gel. Sixty-eight volunteers were randomly allocated into 4 groups: negative control (Control, no treatment), APF-gel application (1.23% F applied for 4 min), and FV application (Duraphat®, 2.26% F) for 4 h (FV-4h) or 24 h (FV-24 h). To evaluate fluoride formed and retained on enamel, acid biopsies were made on the buccal surfaces of the maxillary central incisors before, at the end of the application of fluoride products (immediately after gel application, or after 4 or 24 h of varnish application), and after 7 and 28 days. Fluoride concentration in dental biofilm was also analyzed before and up to 28 days after initial application. The data were analyzed by 2-way ANOVA, considering treatment and time as factors. The APF-gel and FV-24h groups formed greater fluoride concentration on enamel than the FV-4h and the control group at the end of application (p = 0.0001), with no difference from each other (p = 0.99). The groups did not differ regarding fluoride in biofilm fluid (p = 0.73) and solids (p = 0.40). In conclusion, FV needs to remain in contact with the teeth for prolonged times (>4 h) to reach the same reactivity obtained by a 4-min application of APF-gel.

Clinical and radiographic assessment of root canal treatments performed by dental students

Introduction: Retrospective assessment of procedures performed in dental school clinics is a valuable tool to critically assess the teaching/ learning process. Objective: This retrospective study assessed the success rate of root canal treatments executed by dental students during a two-year time span. Material and methods: Patients who had undergone root canal treatments at the clinics of the School of Dentistry of Unochapecó during 2011-2013 were recalled for assessment of the quality of the procedure and the associated coronal restoration. The quality of the root canal treatments was assessed clinically and radiographically, while the coronal restorations were assessed clinically by a trained dental student. Data were analyzed by descriptive statistics and chi-square test (α=0.05). Results: Thirtytwo patients returned for evaluation of 38 root canal treatments and coronal restorations. The success of root canal treatments was 89.5%, while 78.5% of the coronal restorations were considered successful. A significant association was observed between the success of the root canal treatments and the quality of the coronal restoration (p<0.005) and the apical length of the root canal filling (p<0.011). The presence of flaws within the filling material was not significantly associated to the success/failure of the root canal treatment (p=0.459). Conclusion: A high success rate of root canal treatment performed by dental students at an average 13-month evaluation period was observed. An adequate coronal restoration and a good apical sealing is required for a good prognosis of teeth undergoing root canal treatment.