The aim of this study was to determine whether a sustained-release desensitizing gel containing 3% potassium nitrate and 0.11% fluoride ion reduces the risk of tooth sensitivity without compromising the effectiveness of bleaching treatment. Thirty-two patients were randomly assigned to 2 experimental groups: desensitizing gel and placebo. The desensitizing gel or placebo was applied for 30 minutes prior to the at-home vital bleaching gel application. A nightguard dental bleaching treatment (NGVB) using a 16% carbamide peroxide gel was performed for 6 hours over a 3-week period. Patients recorded their tooth sensitivity daily using a 5-point Numeric Rating Scale (NRS). Whiteness index measurements were obtained using a dental spectrophotometer on the upper canines (right and left). The overall risk of sensitivity was 37.5% in the desensitizing gel group compared to 87.5% in the placebo group, yielding a relative risk of 0.42 (95% CI 0.22-0.82), showing a statistically significant difference between the groups (P < .05). During the first week, patients in the placebo group exhibited a higher risk of experiencing mild sensitivity. However, no statistically significant differences in sensitivity intensity were observed overall or during the second and third weeks (P > .05). Regarding color change, the mean difference between groups in the first week was 5.25 (-0.22 to 10.71), in the second week 4.25 (-2.56 to 11.02), and in the third week 2.55(-4.11 to 9.22). No statistically significant differences were found between the groups at any time point (P > .05). The use of a sustained-release desensitizing gel containing 3% potassium nitrate and 0.11% fluoride ion for 30 minutes prior to the bleaching agent effectively reduced sensitivity during at-home bleaching procedures. Furthermore, the desensitizing gel did not impact the effectiveness of the at-home bleaching treatment.

Background: Performing an appropriate Class II direct restoration is a great challenge. The correct selection of the matrix system and the elements used for its stabilization will have a great impact on the result. The aim of this study is to show a new digital method for a predictable selection of the wedge and compare it with the conventional method. Methods: Sixty patients were randomly divided into two groups. In Group 0, the wedge was selected intraoperatively by visual examination, while in Group 1 the wedge was selected preoperatively through the measurement of the cervical embrasure on the bite-wing radiography. The number of wedges used, modifications to them, and tissue damage were registered, along with the quality of the proximal contact and the marginal adaptation. Results: Student’s t-test revealed a statistical difference between the number of wedges used, which was higher in Group 0 (p < 0.05). Pearson Chi-square test showed that tissue damage was statistically higher in Group 0 (p < 0.05), while there was no statistically significant difference between groups in wedge modifications (p > 0.05). Group 1 revealed a higher frequency of satisfactory proximal contact and marginal adaptation (p < 0.05). Conclusions: This new technique reduces wedges waste and tissue damage and provides an adequate interproximal anatomy.

Objectives Non-surgical retreatment of plastic carrier obturators is complex and requires a superior working time. The aim of this study is to present a new retreatment technique and compare it in terms of safety and speed with a conventional method, in curved canals. Methods 36 lower premolars were selected and sealed with plastic core obturators. Then, the samples were randomized into two retreatment groups. In both groups, nickel-titanium rotary instruments (Endogal, Sarria, Lugo, Spain) were used to remove the old filling material. In Group 0 (Direct technique) gutta-percha and plastic core were eliminated simultaneously. In Group 1 (Indirect technique), the plastic core was initially extracted with the aid of an ultrasonic tip and a Hedstroem file, and then, the surrounding gutta-percha was removed with rotary instruments. Results Time needed for retreatment procedures, plastic carrier fracture, ledge formation and apical transportation were significantly lower in Group 1 (P < 0.05), while there was no statistically significant difference between both groups in terms of remaining material and instrument fracture (P > 0.05). No perforations occurred. Conclusions The new indirect technique proved to be safer, since prior withdrawal of the plastic carrier reduces the stress exerted on the rotary instruments and facilitates its advance along the canal, and it also resulted in shorter working time than other previously described methods. Clinical relevance: The increased safety of the technique and the reduction in the retreatment time allows to increase the disinfection duration in cases where a complete removal of the old filling material is not achieved.

Removing plastic carrier obturators during root canal retreatment is challenging and often takes a long time. The aim of this laboratory investigation is t