Fracture resistance and bonding performance after antioxidants pre-treatment in non-vital and bleached teeth.

This study aimed to evaluate the effect of antioxidant solutions on fracture strength and bonding performance in non-vital and bleached (38% hydrogen peroxide) teeth. One hundred and eighty dentin specimens were obtained, 60 for each test: fracture strength, hybrid layer thickness, and bond strength. The groups (n=10) were randomly composed according to post-bleaching protocol: REST - restoration, without bleaching; BL - bleaching + restoration; SA - bleaching, 10% sodium ascorbate solution, and restoration; AT - bleaching, 10% α-tocopherol solution, and restoration; CRAN - bleaching, 5% cranberry solution, and restoration; CAP - bleaching, 0.0025% capsaicin solution, and restoration. Data were analyzed with ANOVA, Kruskal-Wallis, Dunn, and Qui-Square tests (α=0.05). The highest fracture strength values were observed in REST (1508.96 ±148.15 N), without significant difference for the bleached groups (p>0.05), regardless of the antioxidant use. The hybrid layer thickness in the group that was not subjected to bleaching (REST) was significantly higher than in any other group. The bond strength in the bleached and antioxidants-treated groups (SA, AT, CRAN, CAP) has no differences with the bleached group without antioxidants (BL). Adhesive failures were predominant in the groups that did not receive the antioxidant application. In conclusion, the evaluated antioxidants did not show an effect on the fracture strength, hybrid layer thickness, or bond strength of dentin bleached after endodontic treatment. The application of 10% sodium ascorbate, 10% alpha-tocopherol, 5% cranberry, or 0.0025% capsaicin solutions is not an effective step and should not be considered for the restorative protocols after non-vital bleaching.

Effect of the casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF) and photobiomodulation (PBM) on dental hypersensitivity: A randomized controlled clinical trial.

OBJECTIVE: This randomized controlled clinical trial aimed to evaluate the effect of the casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF) and photobiomodulation (PBM) in the treatment of dentin hypersensitivity (DH), and the impact of this on the health-related quality of life (HRQL). METHODS: Eighty teeth with DH were randomized into four groups and received three treatment sessions: PLACEBO = placebo + LASER application mimicking; CPP-ACPF = CPP-ACPF + LASER application mimicking; PBM = placebo + LASER active application; CPP-ACPF+PBM = CPP-ACPF + LASER active application. Tactile (exploratory probe) and evaporative (triple syringe) stimuli were used to measure DH and were recorded with the aid of a visual analogue scale (VAS) after the 1st, 2nd and 3rd treatment sessions and one-month follow-up. The HRQL was recorded in the DH experience questionnaire (DHEQ). RESULTS: The intragroup comparison showed a significant reduction in DH (p < 0.05) with both stimuli after one-month follow-up. The intergroup comparison with the evaporative stimulus showed that CPP-ACPF+PBM significantly reduced DH when compared to the rest of treatments, after one-month follow-up. CPP-ACPF+PBM group statistically differed from the other treatment groups in the DHEQ evaluation after one-month follow-up. CONCLUSION: After one-month follow-up, the association of CPP-ACPF with PBM was effective in the reduction of DH and promoted a positive impact on the HRQL of the participants of this study.

Effect of low-level laser therapy combined with 5000 parts per million fluoride dentifrice on postbleaching sensitivity: A clinical, randomized, and double-blind study.

OBJECTIVE: The aim of this double-blind, randomized, controlled clinical study was to assess the efficacy of low-level laser therapy (LLLT) combined with 5000 ppm fluoride dentifrice on postbleaching sensitivity in teeth exposed to 35% hydrogen peroxide for four weeks. MATERIALS AND METHODS: Twenty-five volunteers were evaluated using the split-mouth model in which the right and left maxillary/mandibular quadrants were randomized and allocated to one of two groups: GPLACEBO, in which the laser tip was positioned without the emission of light (placebo effect) + 5000 ppm sodium fluoride, or GLASER, which comprised LLLT + 5000 ppm sodium fluoride. For both groups, LLLT and placebo were used before bleaching, whereas fluoride was applied after bleaching. LLLT was applied at two points: on the central cervical and medial regions of the incisors, canines, and premolars in the corresponding hemi-arch. At each point, 60 J/cm2 was applied for 16 seconds with an irradiance of 3.75 W/cm2 using the therapeutic infrared device. To assess tooth sensitivity, a modified visual analogue scale was used after an evaporative stimulus, and a daily pain questionnaire was also applied. RESULTS: The Wilcoxon and Friedman tests demonstrated a significant difference in the incidence of sensitivity pain between GPLACEBO and GLASER (P ≤ .05), with different evaluation times. CONCLUSION: Teeth treated with laser therapy in combination with the topical use of sodium fluoride at each bleaching session demonstrated less sensitivity compared with the application of sodium fluoride only. CLINICAL SIGNIFICANCE: The use of a low-level laser therapy in combination with topical use of sodium fluoride improves symptoms of dentin sensitivity at each bleaching session.