This study aimed to evaluate the in vitro performance of collagen-based sponges as a drug delivery system for intracanal antimicrobial administration. Four groups of loaded collagen-based sponges (A, 0.3% w/v amoxicillin trihydrate: potassium clavulanate (4:1); B, 0.03% w/v chlorhexidine gluconate [CHX]; C, 0.3% w/v amoxicillin trihydrate: potassium clavulanate (4:1) and 0.03% w/v CHX; D, 1% w/v amoxicillin trihydrate: potassium clavulanate (4:1) and 0.03% w/v CHX) were designed. Release kinetics were tested in vitro on cultures in Petri dishes, and the effect on bacterial biofilms was studied ex vivo on 114 extracted human single-rooted teeth. Biofilm formation was tested by scanning electron microscopy (SEM). Collagen sponges containing amoxicillin and chlorhexidine showed a time-sustained antimicrobial effect in vitro and were also able to destroy mature biofilms ex vivo. This datum was validated by means of SEM-based study of E. faecalis and S. aureus biofilms.

Gingival irritation is a common side effect of at-home bleaching, but how the design of the bleaching tray affects its occurrence is unclear. The purpose of this randomized clinical trial was to determine whether a direct relationship is present between the design of bleaching trays and the risk of gingival irritation during at-home bleaching treatments. This clinical trial was registered at ClinicalTrials.gov. (NCT06371664). Seventy-two participants were randomly assigned to 2 experimental groups: extended bleaching tray (3 mm) and nonextended bleaching tray (1 mm). Over a period of 3 weeks, participants underwent a nightguard dental bleaching treatment (6 to 8 hours) using 16% carbamide peroxide gel. Gingival irritation was evaluated subjectively by participants daily and objectively by clinicians at each visit. Tooth sensitivity was recorded daily using a 5-point numerical scale. Tooth color measurements were also made with a dental spectrophotometer. The risk of gingival irritation and the risk and intensity of tooth sensitivity were analyzed with the Pearson chi squared test and Fisher exact test. The color analysis was conducted with the Student t test (α=.05). Subjectively, the risk of gingival irritation was 66.7% in the extended group and 47.2% in the nonextended group, showing no statistically significant difference (P>.05). However, objectively, the risk of gingival irritation was significantly higher in the extended group (88.9%) compared with the nonextended group (63.9%) (P=.01(95% CI 1.06 to 1.83). Tooth sensitivity intensity was significantly higher in the extended tray group (P<.001), although the design did not significantly influence the risk of tooth sensitivity (P>.05). No significant differences were found between groups regarding color change (P>.05). The use of an extended bleaching tray design increases the risk of gingival irritation and the intensity of tooth sensitivity. Therefore, the nonextended tray is recommended to minimize adverse reactions.

The aim of this study is to analyze the effects of different endodontic irrigants and adhesive systems on the resin bond strength of fiber post cementation. In total, 144 single-rooted, unrestored human teeth were endodontically treated and randomly divided into 12 groups according to four endodontic irrigants (distilled water as control; EDTA 17%; NaOCl 5%; chlorhexidine digluconate 2%) and three different adhesive/resin cement systems (etch-and-rinse: orthophosphoric acid, Parabond^® A+B/Paracore^®; self-etch: ParaBond^® Non-Rinse Conditioner, Parabond^® A+B/Paracore^®; Universal: Clearfil^TM Universal Bond/Clearfil^TM DC Core Plus). Forty-eight hours after post cementation, ten teeth from each group were cross-sectioned into three discs (cervical, middle and apical regions). Thirty specimens of each group (n = 30) were submitted to a push-out test at a crosshead speed of 1 mm/min. The remaining two teeth of each group were sectioned in the same manner, and the resin–dentin interface was evaluated using scanning electron microscopy (SEM). The results were statistically analyzed with the ANOVA test and Tukey’s test (p < 0,01). The adhesive protocols and post space region showed no significant effect on bond strength (p > 0.01). The combination of NaOCl 5% and ClearfilTM Universal Bond reduced the adhesive strength (p < 0.01). The NaOCl 5%, in relation to other irrigants, significantly decreased the push-out bond strength.

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.