Tatiane Cristina Dotta

This in vitro study evaluated the effects of adding chitosan (Chi) to desensitizing agents applied before dental bleaching on enamel properties. Bovine enamel specimens were allocated to seven groups ( n = 12): no treatment (negative control), 2% NaF (positive control), 2% NaF + 2% Chi, 2% NaF + 5% Chi, 2% NaF + 5% KNO ₃ , 2% NaF + 5% KNO ₃ + 2% Chi, and 2% NaF + 5% KNO ₃ + 5% Chi. All specimens underwent three bleaching sessions with 35% hydrogen peroxide, each preceded by a 10‐min application of desensitizing agents. Color change (∆ L *, ∆ a *, ∆ b *, ∆ E _ab , and ∆ E ₀₀ ), whiteness index (∆WI _D ), surface roughness ( R _a ), and microhardness (SMH) were evaluated at baseline (T0) and after each session (T1–T3). Scanning electron microscopy analysis was performed at T3. Color parameters did not differ among groups ( p > 0.05), indicating bleaching efficacy. Surface roughness increased in all groups ( p < 0.0001), with greater increases in chitosan‐containing groups. However, groups 2% NaF + 5% Chi and 2% NaF + 5% KNO ₃ + 5% Chi showed significantly higher microhardness values than controls at T2 and T3. Incorporation of chitosan into desensitizing agents increased enamel surface roughness but preserved microhardness without compromising bleaching efficacy. These findings suggest chitosan may represent strategy for protecting enamel during in‐office bleaching.

Dental bleaching is a widely used esthetic procedure often associated with oral hygiene products such as mouth rinses. However, the effects of different mouth rinse formulations on enamel during bleaching remain unclear. This study evaluated in vitro the properties of dental enamel exposed to mouth rinses with different active ingredients during at-home bleaching with 10% carbamide peroxide. Bovine enamel-dentin discs were randomly assigned to four groups (n=12): distilled water (DW, control), Listerine Cool Mint Zero Alcohol (CMZ, essential oils), Listerine Cool Mint (CM, essential oils + alcohol), and Listerine Whitening Extreme (WE, essential oils + alcohol + hydrogen peroxide). Bleaching was performed for 4 h/day for 14 days, and mouth rinses were applied twice daily. Color parameters (ΔL* ,Δa*, Δb*, ΔE, ΔE), surface roughness (Ra), and microhardness (KHN) were evaluated at baseline and after treatment. Surface morphology was analyzed by scanning electron microscopy (SEM). Data were analyzed using linear mixed models, generalized linear mixed models, and Kruskal-Wallis tests (α=0.05). No significant differences among groups were observed for color change or surface roughness (p›0.05). All groups showed a significant reduction in microhardness over time (p‹0.05). CMZ and CM exhibited the greatest decrease in microhardness at the final evaluation, differing significantly from the other groups (p‹0.05). SEM images revealed similar surface alterations in all groups, including porosity and depressions. Mouth rinses did not affect bleaching effi cacy or enamel color. Although enamel microhardness, roughness, and morphology changed after bleaching, only microhardness and morphological alterations were influenced by the active ingredients of the mouth rinses. Clinical relevance: The use of mouth rinses during at-home bleaching with carbamide peroxide does not compromise the bleaching efficacy. However, it may adversely affect the properties of dental enamel.

The incorporation of antimicrobial agents into 3D-printed resins may improve their biological performance; however, their effects on physicochemical and mechanical properties remain unclear. This study evaluated the influence of phosphorylated chitosan (P-Chi; 0.25% and 0.50% w/w) incorporated into short- (ST) and long-term (LT) 3D-printed dental resins. Surface, mechanical, optical, and antibacterial properties against Streptococcus mutans were investigated using standardized methods. FTIR confirmed the successful phosphorylation and incorporation of P-Chi into both resin matrices. P-Chi significantly reduced S. mutans CFU counts compared with the control (p < 0.001, η²p = 0.286), regardless of concentration, although no inhibition halos were detected, indicating a contact-dependent antimicrobial mechanism. Enhanced antibacterial activity was accompanied by increased surface roughness and wettability. Nanoparticle concentration significantly affected mechanical performance (p = 0.001), whereas resin type did not (p = 0.613). The 0.25% groups exhibited lower flexural strength and microhardness than the controls (p < 0.05), while the 0.50% groups maintained flexural strength comparable to that of the controls, with G6 showing the highest elastic modulus (3494.95 ± 301.30 MPa). Color variation was influenced by resin type rather than P-Chi concentration (p < 0.05). Overall, P-Chi enhanced antibacterial activity while maintaining clinically acceptable mechanical properties, supporting its use as a multifunctional additive for biofunctional 3D-printed provisional resins.

Aim: This in vitro study evaluated the effects of different mouth rinses in combination with 10% carbamide peroxide bleaching gel on the properties of resin composite. Methods: Cylindrical specimens of a nanofilled resin composite (n = 12) were allocated to four groups: distilled water (control, C), mouth rinse with essential oils (EO), mouth rinse with essential oils and alcohol (EO+A), and mouth rinse with essential oils, alcohol, and hydrogen peroxide (EO+A+HP). Samples were bleached daily for 14 days with 10% carbamide peroxide gel for 4 hours and immersed in 5 mL of the assigned mouth rinse before and after bleaching. Surface microhardness (SMH), surface roughness (Ra), and color changes (ΔL*, Δa*, Δb*, ΔEab, and ΔE00) were assessed at baseline (T1) and post-treatment (T2). Data were analyzed using generalized linear mixed models and Kruskal–Wallis/Dunn tests. Results: All groups exhibited decreased SMH and increased Ra at T2. No significant differences in SMH were observed among groups, whereas Ra was highest in the EO+A+HP group. The EO+A and EO+A+HP groups showed greater Δa* and ΔE00 values compared with the control. Conclusion: Mouth rinses used during 10% carbamide peroxide bleaching increase roughness, reduce microhardness, and alter resin composite color, depending on their active ingredients.

Dental bleaching is a widely used esthetic treatment, but concerns persist regarding its potential effects on enamel integrity. The incorporation of remineralizing and protective agents into bleaching gels, such as calcium and chitosan, has been proposed to mitigate these effects. Objective: This in vitro study evaluated the effects of adding 2% chitosan to at-home bleaching gels with and without calcium on enamel physical properties. Methodology: Bovine enamel specimens stained with black tea were assigned to five groups (n = 12): control (no bleaching), 7.5% hydrogen peroxide (7.5% HP), 7.5% HP + 2% chitosan (7.5% HP+ Chi), 7.5% HP + calcium (7.5% HP + Ca), and 7.5% HP + calcium + chitosan (7.5% HP + Ca + Chi). Bleaching was performed for 14 days (1 hour/day). Color (∆L*, ∆a*, ∆b*, ∆Eab, ∆E00, and ∆WID), surface roughness, and surface microhardness (SMH) were evaluated at baseline (T1) and after treatment (T2). Mineral content (Ca, P, and the Ca/P ratio) was assessed by energy-dispersive X-ray spectroscopy and enamel morphology by scanning electron microscopy. Statistical analyses included the Kruskal-Wallis and Dunn's tests, mixed models, and ANOVA. Results: Groups containing chitosan (7.5% HP + Chi and 7.5% HP + Ca + Chi) showed the lowest surface roughness and the highest microhardness values. For these groups, SMH showed no decrease after treatment (T2), remaining similar to the initial values (T1). Color changes were similar among all bleached groups. Calcium, phosphorus, and Ca/P levels were the same for all groups. Conclusion: Adding 2% chitosan to 7.5% hydrogen peroxide-based at-home bleaching gels appears to be a promising approach to protect enamel against changes in roughness, microhardness, and mineral content without compromising bleaching efficacy.

To evaluate the effects of different whitening toothpastes on bovine tooth enamel during at-home bleaching with 10% carbamide peroxide. Enamel-dentin specimens were randomly assigned to five groups based on the toothpaste used: distilled water (DW), regular toothpaste (RT), whitening toothpaste with abrasive agents (WT), whitening toothpaste with abrasive and chemical agents (PT), and whitening toothpaste with abrasive, chemical, and bleaching agents (HP). All specimens underwent brushing and bleaching procedures for 14 days. Surface microhardness (SMH), surface roughness (Ra), and color parameters (ΔL*, Δa*, Δb*, ΔE*ab, and ΔE*₀₀) were analyzed. Data were statistically evaluated using two-way ANOVA followed by Tukey's post-hoc test (α= 0.05). All groups showed a significant reduction in SMH and an increase in Ra between the initial and final timepoints (P< 0.05). At the final evaluation, PT showed intermediate values, while HP presented the highest SMH, differing significantly from all other groups. For surface roughness, the WT group exhibited the highest Ra, while RT had the lowest values among the toothpaste groups. No significant differences were observed for ΔE*ab and ΔE*₀₀ between groups (P> 0.05). Whitening toothpastes used concomitantly with at-home dental bleaching do not enhance the whitening effectiveness; however, they may cause changes to the enamel surface. Whitening toothpastes used concomitantly with at-home bleaching do not enhance whitening effectiveness but may negatively affect enamel surface properties by increasing roughness and reducing microhardness.

Pediatric dentistry continually seeks effective and efficient treatments for young patients, especially within pediatric endodontics, where cooperation can often be challenging. This in vivo study aimed to evaluate the effectiveness of a novel photodynamic therapy (PDT) protocol using a 5-aminolevulinic acid gel (Aladent, ALAD) combined with light irradiation during the endodontic treatment of primary teeth. This study included primary teeth requiring root canal therapy due to carious lesions or trauma, with clinical symptoms suggesting irreversible pulpitis or acute apical periodontitis. Following local anesthesia and isolation with a rubber dam, carious lesions were excavated, and access to the pulp chamber was established. Canal preparation included determining the working length and using a sequence of k-files. Afterward, ALAD gel was applied, and the patients were divided into two groups based on their visit duration (Group A with a single visit, Group B returning after one week). Microbiological analysis was conducted on the samples taken before and after treatment. The findings demonstrated significant antibacterial efficacy of the PDT protocol in reducing root canal bacterial load, suggesting ALAD-based PDT may serve as an alternative to traditional endodontic treatment in cases where retaining primary teeth is essential for orthodontic or strategic reasons. Clinically, improvement in symptoms and fistula resolution were observed. Treatment time, patient compliance, and protocol safety in pediatric applications are also discussed, highlighting the protocol’s potential to enhance clinical outcomes in pediatric endodontics.

Different diluents are used to prepare toothpaste slurries in vitro and in situ erosive tooth wear studies. This study aimed to evaluate the influence of diluents on the anti-erosive potential of toothpastes with different active agents. Bovine enamel specimens were assigned to groups (n = 12) according to slurry type (in vitro deionized water, in vitro remineralizing solution, clarified human saliva, or in situ human saliva) and toothpaste formulation: placebo (0 ppm F), sodium monofluorophosphate (1450 ppm F - MFP), sodium fluoride (1450 ppm F - NaF), stannous fluoride + sodium fluoride (1100 ppm F SnF₂ + 350 ppm F NaF - NaF/SnF₂), or chitosan (0.5%) + sodium fluoride (700 ppm F) + amine fluoride (700 ppm F) - Chi/NaF/AmF. A 5-day erosion cycle was performed, intercalating four erosive challenges (1 min, 1% citric acid, pH 3.5) and two remineralizing treatments, applied before the first and after the last erosive challenge each day (brushing for 15 seconds and immersion in slurry for up to 2 minutes). Surface microhardness (SMH) and tissue loss by contact profilometry were measured, and percentage SMH loss (%SMH) was calculated. Across all toothpastes, in situ human saliva resulted in the highest SMH and lowest tissue loss. Under in vitro conditions, NaF/SnF₂ and Chi/NaF/AmF slurries with human saliva yielded the best outcomes. For other formulations, no significant differences were observed between in vitro diluents. Results indicate that the diluent type influences SMH and profilometry outcomes, depending on the active agents. Toothpaste containing Sn, chitosan, and fluoride showed the most significant anti-erosive potential.

This study evaluated the efficacy of semisolid systems (gels) and films containing a combination of metronidazole (MTZ) and metronidazole benzoate after scaling and root-planing (SRP) for periodontitis. In total, 45 patients with stage I or II periodontitis were enrolled and divided into 3 groups: 1—SRP—control; 2—SRP + Film with MTZ; 3—SRP + Gel with MTZ. The pH of gingival crevicular fluid (GCF) before/after treatments, MTZ concentrations, and drug release using high-performance liquid chromatography were investigated. The effects were evaluated by longitudinal monitoring of clinical parameters (probing depth—PD, clinical attachment level—CAL, and bleeding on probing—BP). MTZ and MTZ-benzoate concentrations in the periodontal pocket and pH showed no statistical difference after application. SRP + Gel presented the lowest CAL values. For SRP + Film and SRP + Gel, higher PD values were observed at T0 compared to all groups. A relevant reduction in BP was observed in SRP + Film and SRP + Gel groups at all times compared to T0. Both therapies improved periodontal health compared to SRP alone, reducing PD and BP, and increasing CAL for the gel group, suggesting they are promising for periodontal disease treatment.