Effect of Bleaching Gel Concentration on Tooth Color and Sensitivity: A Systematic Review and Meta-analysis

Is at-home bleaching more effective on the upper arch than the lower arch? A prospective cohort study

OBJECTIVE

Teeth bleaching is one of the most popular aesthetic dental treatments, uses to address both extrinsic and intrinsic tooth discoloration. However, variations in bleaching efficacy between the upper and lower dental arches are commonly observed. Sublingual salivary glands may play a role in these differences by increasing saliva contamination of bleaching trays, which accelerates the degradation of bleaching gel and may reduce its effectiveness in the lower arch. This study aims is to evaluate and compare the effectiveness of bleaching treatments in the upper and lowe arches.

METHODS

This study employed a prospective observational cohort design with a split-mouth approach. Thirty-two participants completed a three-week bleaching regimen using 16 % carbamide peroxide. Color changes were assessed using the CIELAB, CIEDE2000, and Whiteness Index for Dentistry (WID) formulas, with spectrophotometric measurements taken at baseline and weekly intervals.

RESULTS

No statistically significant differences (p > 0.5) in bleaching efficacy for incisors between the two arches. However, upper canines demonstrated significantly greater bleaching effectiveness than lower canines by the second and third weeks (p < 0.05), as indicated by the CIELAB and CIEDE2000 formulas. No significant differences (p > 0.05) were observed using the WID formula.

CONCLUSION

While the lower canines exhibited slightly reduced bleaching effectiveness, these differences were not clinically noticeable, affirming the overall efficacy of the treatment for both arches.

CLINICAL SIGNIFICANCE

At-home bleaching treatment demonstrates equivalent effectiveness in both dental arches. While the lower canines may achieve a slightly reduced degree of bleaching, these differences are not clinically noticeable. Consequently, extending the duration of the bleaching treatment for the lower arch is unnecessary.

Effect of copaiba oil-resin on dental sensitivity control and color change after bleaching: A randomized clinical trial

OBJECTIVE

This randomized clinical trial evaluated a copaiba oil-based gel in controlling dental sensitivity (DS) and color change after dental bleaching.

MATERIALS AND METHODS

Seventy-five volunteers were randomized into three groups (n = 25): GC (placebo gel - negative control); GKF2% (gel of 5% potassium nitrate and 2% sodium fluoride - positive control); and GCO (copaiba oil gel). Three bleaching sessions were performed using 35% hydrogen peroxide (HP 35%), with 7-day intervals. The desensitizing gels were applied for 10 min in each group. The DS was evaluated over 21 days using a visual analog scale (VAS). Color evaluation was done with a spectrophotometer before and after bleaching using the CIEDE2000. The DS was assessed between groups (Kruskal-Wallis test) and within groups (Friedman test). The color change was analyzed using one-way ANOVA and Tukey's test.

RESULTS

GCO and GKF2% showed the lowest sensitivity values, with no significant difference (p < 0.05). In the intragroup analysis, GCO and GKF2% showed no differences across the three whitening sessions (p = 0.974, p = 0.213, p = 0.143, respectively). Conversely, GC exhibited an increase in DS after the last session (p = 0.035). All groups showed color change, without statistically significant differences between the groups (p = 0.725).

CONCLUSION

The copaiba gel reduced dental sensitivity after treatment with 35% hydrogen peroxide, without affecting the bleaching effectiveness.

CLINICAL RELEVANCE

The topical application of the experimental copaiba oil gel was effective in reducing dental sensitivity after bleaching with 35% hydrogen peroxide.

Clinical decision-making in tooth bleaching based on current evidence: A narrative review

OBJECTIVE

This review consolidates current knowledge on dentist-supervised tooth bleaching for vital teeth, drawing from systematic reviews, meta-analyses, and randomized clinical trials (RCTs) that followed CONSORT guidelines.

DATA RESOURCES

MeSH and free terms like "tooth bleaching," "tooth whitening," "randomized clinical trial," and "systematic review" were used in PubMed, Scopus, and Web of Science databases STUDY SELECTION: Out of 839 articles, 444 were selected for full-text review, excluding case reports, non-randomized trials, literature reviews and those not directly related to tooth bleaching or RCTs not following CONSORT 2010. The remaining 203 studies were used to compare the dentist-supervised at-home and in-office clinical protocols, assessing factors such as color change, tooth sensitivity, and gingival irritation. In vitro studies were cited to support and explain basic concepts of different clinical decisions CONCLUSIONS: Daily at-home bleaching with 10 % carbamide peroxide or lower-concentration hydrogen peroxide over three to four weeks is effective. In-office bleaching with high-concentration hydrogen peroxide exhibits variations in protocols based on the HP concentration and gel's pH. Emerging technologies like violet LEDs and photobiomodulation with infrared lasers show promise in enhancing efficacy and reducing sensitivity, respectively, though more research is needed. The review underscores the importance of ongoing research into desensitization strategies to manage sensitivity related to bleaching.

CLINICAL SIGNIFICANCE

Tooth bleaching is central to dental aesthetics, offering a range of options that can challenge clinicians. Adverse effects, particularly sensitivity, highlight the need for practice supported in protocols clinically tested and effective desensitization approaches.

An experimental bleaching gel containing a nanocomposite reduces the intensity of postoperative tooth sensitivity: A randomized, triple blind clinical trial

OBJECTIVE

To evaluate the effects of incorporating a hydroxyapatite-capsaicin nanocomposite (HAp-CAP) into a 35 % hydrogen peroxide (HP) experimental bleaching gel on tooth sensitivity (TS) risk and intensity, bleaching effectiveness (BE), and patient satisfaction.

MATERIALS AND METHODS

In a split-mouth, triple-blind, randomized controlled clinical trial, 54 participants received dental bleaching with two bleaching gels: 35 % HP+HAp-CAp, or 35 % HP alone (1 × 50 min; one-week interval). TS was recorded immediately, and at 1, 24, and 48 h post-bleaching using a 0-10 visual analogue scale (VAS). Color was evaluated before bleaching, one week after each session, and one month after treatment (ΔSGUs, ΔEab, ΔE00, and WID). Patient satisfaction was recorded by a 0-10 VAS. TS was evaluated by McNemar's test and paired t-test. BE and patient satisfaction between groups were compared using paired t-test (α = 0.05).

RESULTS

87 % of participants experienced discomfort, regardless of the study group. The TS intensity differed between groups at all assessment times, favoring 35 % HP+HAp-CAp (p < 0.05). Significant BE occurred in all groups, with no significant difference between them (p > 0.05 for ΔSGUs, ΔEab, ΔE00, and WID). Patient satisfaction was high for both groups, without difference between them (p = 0.62).

CONCLUSIONS

The 35 % HP+HAp-CAP bleaching gel did not reduce the risk but reduced the intensity of TS and did not affect BE.

CLINICAL RELEVANCE

The addition of a hydroxyapatite-capsaicin nanocomposite to in-office bleaching gels reduced the tooth sensitivity intensity without compromising bleaching effectiveness.

Clinical evaluation of in-office bleaching with low, medium, and high concentrate hydrogen peroxide: a 6-month a double-blinded randomized controlled trial

OBJECTIVE

The study evaluated the longevity, efficacy, sensitivity, and impact on the oral health-related quality of life of in-office dental bleaching using low, medium, and high concentrate hydrogen peroxide.

MATERIAL AND METHODS

Randomized, parallel, and double-blinded clinical trial was performed with 54 participants using18% hydrogen peroxide (HP), 25%HP, and 40%HP in-office bleaching agent. Tooth color was evaluated at baseline, after the 1st session bleaching, after the 2nd session bleaching and 6 months after finishing the bleaching using spectrophotometer. Tooth sensitivity (TS) was measured with the Visual Analog Scale at baseline, immediately after bleaching, after 1 day, and after 7 days. The impact on quality of life was evaluated using the 14-item Oral Health Impact Profile (OHIP-14) questionnaire at baseline, and 6 months after bleaching. The data were analyzed using the Kikare test, Kruskal Wallis test, one-way ANOVA, Wilcoxon, Friedman, Mann-Whitney (p < 0.05).

RESULTS

All groups achieved similar levels of bleaching during all evaluation times (p > 0.05), surpassing perceived value. There was no difference in TS levels among groups at all evaluation times (p > 0.05). TS significantly increased after bleaching (p < 0.05), decreased significantly after 24 h (p < 0.05), and there was no difference no difference between the initial sensitivity levels after 7 days (p > 0.05). All groups reported improved aesthetic self-perception following bleaching (p < 0.05) and there was no difference between the groups (p > 0.05).

CONCLUSION

Low, medium, and high concentrations of HP did not affect both the final tooth color and the reported TS intensity, regardless of the evaluation time. In-office bleaching provides positive effects on aesthetic perception and different HP concentrations have not influenced this positive effect.

CLINICAL SIGNIFICANCE

In this study, the efficacy, longevity, sensitivity, and impact on oral health-related quality of life of in-office bleaching using low, medium, and high concentration hydrogen peroxide agents from the same manufacturer were found to be similar. However, these results cannot be extrapolated to other in-office high-concentration hydrogen peroxide gels.

CLINICAL TRIAL REGISTRATION NUMBER

NCT06700434.

Protective role of calcium-based agents in dental bleaching gels: insights from a systematic review and meta-analysis of clinical and laboratory evidence

OBJECTIVES

This systematic review and meta-analysis (SRM) evaluated the effect of incorporating calcium-based bioactive agents in bleaching gels on dental structure preservation and whitening efficacy.

METHODS

A comprehensive search was conducted across databases up to November 2024. Two independent reviewers screened and selected clinical trials and in vitro studies evaluating the effects of calcium-based bioactive agents in bleaching gels, following predefined PICO criteria. Data extraction and quality assessments were performed using the Cochrane Collaboration tool and Joanna Briggs Institute Critical Appraisal Tools. Meta-analyses were conducted with RevMan software, using the mean difference as the effect measure.

RESULTS

Out of 4,289 articles identified, 56 met the inclusion criteria, consisting of 50 in vitro studies and 6 clinical trials. The agents evaluated included calcium ions, calcium gluconate, amorphous calcium phosphate, CPP-ACP, and calcium polyphosphate. Overall, all agents reduced the adverse effects associated with bleaching therapy, such as minimizing changes in the mechanical and morphological properties of enamel, reducing transamelodentinal diffusion, and clinically decreasing tooth sensitivity. None of the calcium-based agents interfered with the bleaching effect. In short, the studies demonstrated a low risk of bias.

CONCLUSIONS

Calcium-based agents incorporated into bleaching gels reduced bleaching-induced changes in dental tissues and demonstrated clinical aesthetic results comparable to conventional gels. However, further clinical trials are needed to optimize formulations, application protocols, and confirm the findings of this study.

CLINICAL RELEVANCE

This SRM provides evidence that these agents offer additional benefits by enhancing the biocompatibility and safety of whitening therapy over conventional treatments, guiding clinicians in material selection for whitening procedures.

A TRIPLE-BLIND RANDOMIZED CLINICAL TRIAL COMPARING THE EFFICACY OF A DESENSITIZING AGENT USED WITH AN AT-HOME BLEACHING TECHNIQUE

PURPOSE

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.

METHODS

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).

RESULTS

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).

CONCLUSIONS

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.

Effect of the reduction in the exposure time to at-home bleaching gel on color change and tooth sensitivity: A systematic review and meta-analysis

OBJECTIVE

To investigate the effect of reducing exposure time to at-home bleaching gel on color change and tooth sensitivity.

MATERIALS AND METHODS

The search was carried out using PubMed, Scopus, Web of Science, EMBASE, LILACS, Cochrane. Randomized clinical trials (RCTs) were included involving adult patients who have never undergone bleaching treatment before (P), subjected to bleaching with a reduced exposure time to the at-home bleaching agent (I) compared to those who used it for the time indicated by the manufacturer (C), to evaluate the effects on color change and tooth sensitivity (O). The Cochrane guidelines for the Risk of Bias Assessment Tool (RoB 2.0) and GRADE were used to assess risk of bias and quality of evidence, respectively.

RESULTS

Using at-home bleaching gel for the period recommended by the manufacturer resulted in significantly higher ΔEab and ΔWID values and better subjective color change (ΔSGU-Classical), regardless of the evaluation time. Regarding the post-bleaching evaluation, no significant differences were found for ΔE00 immediately after bleaching or ΔSGU (Bleached) at any time. Reducing the time of use significantly decreased tooth sensitivity events.

CONCLUSIONS

Reducing exposure time to at-home bleaching gel reduces tooth sensitivity events; however, most of the parameters that assess color change indicate using at-home bleaching gel for the time recommended by the manufacturer.

CLINICAL SIGNIFICANCE

Reducing exposure time to at-home bleaching gel should be applied with caution in clinical practice. Although the evidence suggests a reduction in tooth sensitivity events, bleaching effectiveness was significantly higher after using the bleaching gel for the time indicated by the manufacturer.

Bleaching efficacy of in-office bleaching with violet light using low-concentration hydrogen peroxide nanoparticulate photocatalyst gel: A randomized controlled trial

OBJECTIVE

This randomized controlled trial aimed to evaluate the bleaching efficacy and tooth sensitivity (TS) of participants submitted to different application protocols of in-office bleaching with violet light using 6 % hydrogen peroxide (HP) nanoparticulate photocatalyst gel.

MATERIALS AND METHODS

Sixty-six participants were randomized and bleached using either a 6 % HP (Nano White, DMC), and/or violet light (Bright Max Whitening, MMOptics), according to the following protocols: 1) only violet light (VIOL); 2) only bleaching gel application (BG) and; 3) combined bleaching gel application + violet light (BG+VIOL). The bleaching efficacy was evaluated with the Vita Easyshade spectrophotometer, Vita Classical and Vita Bleachedguide scales. The risk and intensity of TS were recorded using a 0-10 visual analogue scale (VAS) and a 0-4 numerical scale (NRS). Color change and intensity of TS values were compared using one-way ANOVA and Tukey's test were used. The absolute risk of TS was compared using the Chi-square test (α = 0.05).

RESULTS

A significant and higher degree of bleaching was observed in the BG and BG+VIOL groups compared to the VIOL group (p < 0.003). Despite no significant differences in the risk (p > 0.07) and intensity (p > 0.28) of TS among groups, a higher risk of TS was observed in the BG and BG+VIOL groups.

CONCLUSIONS

Using VIOL reduced the risk of TS but did not improve bleaching. However, BG+VIOL with low-concentration HP nanoparticulate photocatalyst gel achieved equal efficacy and was less likely to cause TS compared to BG.

Tooth sensitivity in different arches post in-office dental bleaching: A multicenter randomized controlled trial

OBJECTIVE

To compare the risk and intensity of tooth sensitivity (TS) and gingival irritation (GI), as well as bleaching efficacy (BE) in the maxillary and mandibular arches after in-office dental bleaching.

MATERIALS AND METHODS

90 participants were randomly into two groups according to the arch (maxillary or mandibular) in which the patient will first receive a 35 % hydrogen peroxide gel (2 sessions; 1 × 30 min; 1 week apart). TS and GI were recorded immediately after, up to 1 h, 24 h and 48 h after bleaching, using the 0-10 Visual Analogue Scale (VAS). BE was assessed before bleaching and 30 days after the end of the treatment (shade guide units [ΔSGU], CIELab [ΔEab], CIEDE2000 [ΔE00], and Whiteness Index for Dentistry [WID]). TS and GI were compared using McNemar's and paired t-test. BE were compared with Wilcoxon Signed Rank Test (ΔSGU) and paired t-test (ΔEab, ΔE00, and WID) (α = 0.05).

RESULTS

The risk and the intensity of TS was statistically higher for the mandibular arch (p < 0.003). The risk and intensity of GI did not differ between arches (p > 0.38). Both arches demonstrated significant BE (ΔSGU, ΔEab, ΔE00 and WID), without differences between them (p > 0.08).

CONCLUSIONS

In-office dental bleaching induces higher risk and the intensity of TS in the mandibular arch when compared to maxillary arch, without significant differences in gingival irritation, or bleaching efficacy.

CLINICAL RELEVANCE

Most patients experience tooth sensitivity regardless of the dental arch involved. However, when performing in-office dental bleaching, clinicians should consider that the mandibular arch is more likely to experience greater sensitivity compared to the maxillary arch.

Effect of a novel low-concentration hydrogen peroxide bleaching gel containing nano-sized sodium trimetaphosphate and fluoride

OBJECTIVES

To evaluate in vitro the effects of nano-sized sodium trimetaphosphate (TMPnano) and sodium fluoride (F) added to a 17.5 % hydrogen peroxide (H2O2) bleaching gel on the color change, enamel mechanical and morphological properties, and H2O2 transamelodentinal diffusion.

MATERIALS AND METHODS

Bovine enamel/dentin discs (n = 180) were divided according to the bleaching gel: 17.5 % H2O2 (17.5 % HP); 17.5 % H2O2 + 0.1 % F (HP/F); 17.5 % H2O2 + 1 % TMPnano (HP/TMPnano); 17.5 % H2O2 + 0.1 % F + 1 % TMPnano (HP/F/TMPnano) and 35 % H2O2 (35 % HP). The gels were applied for 40 min on three sessions, each session spaced 7 days apart. The total color change (ΔE*ab) according to the Commission Internationale de l'Eclairage (CIE) L*a*b* color change measured by CIEDE2000 (ΔE00), whitening index (ΔWID), surface hardness (SH), surface roughness (Ra), cross-sectional hardness (ΔKHN), and transamelodentinal diffusion were assessed. Enamel surfaces were examined using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDS) analysis. The data were analyzed using ANOVA, followed by the Student-Newman-Keuls test (p < 0.05).

RESULTS

ΔE*ab, ΔE00, and ΔWID values were comparable among the gels that produced a bleaching effect post-treatment (p < 0.001). The HP/F/TMPnano group exhibited lower mineral loss (SH and ΔKHN), Ra, and H2O2 diffusion compared to the 17.5 % HP and 35 % HP groups, which had the highest values (p < 0.001). SEM/EDS analysis revealed surface changes in all bleached groups, though these changes were less pronounced with F/TMPnano.

CONCLUSIONS

The 17.5 % HP gel containing F/TMPnano maintains the bleaching effect while reducing enamel demineralization, roughness, H2O2 diffusion, and enamel morphological changes.

CLINICAL RELEVANCE

Low-Concentration H2O2 bleaching gel containing F/TMPnano can be used as a novel approach to enhance safety and maintain the performance of aesthetic effects.

Tooth Sensitivity Following Hydrogen Peroxide Bleaching With and Without Ozone: A Randomized Controlled Trial: Tooth Sensitivity Following H2O2 Versus H2O2/Ozone Bleaching

Aims: The aim of this investigation was to assess bleaching sensitivity following bleaching using either 38% H2O2 only or 38% H2O2 followed by ozone application. Methods: In this randomized controlled clinical investigation, 80 participants (40 females and 40 males) were randomly assigned to two groups (n = 40 each; 20 females and 20 males). The upper anterior teeth were bleached by 38% H2O2 for 20 min followed by ozone application for 60 s (healOzone X4, KaVo Dental, Biberach, Germany) in Group 1 (test group). Meanwhile, the bleaching protocol in Group 2 (controls) included the application of just 38% H2O2 for 20 min. Tooth sensitivity before and after bleaching was reported by the participants using a visual analog scale (VAS) from 0 to 10. Mann-Whitney U test, Wilcoxon signed-rank test, and regression analysis were used to analyze the data. Significant statistical outcomes were identified at p < 0.05. Results: Bleaching sensitivity was reported following both tested bleaching protocols (p < 0.001). However, less bleaching sensitivity was reported when ozone was applied for 60 s after bleaching with 38% H2O2 (p < 0.001). Female participants reported more bleaching sensitivity regardless the applied bleaching protocol (p < 0.05). Conclusions: Bleaching protocols with 38% hydrogen peroxide were associated with less bleaching sensitivity when followed by ozone application on the teeth.

Co-doped titanium dioxide nanoparticles decrease the cytotoxicity of experimental hydrogen peroxide gels for in-office tooth bleaching

OBJECTIVE

To evaluate the efficacy and cytotoxicity of experimental 6% and 35% hydrogen peroxide gels (HP6 or HP35) incorporated with titanium dioxide nanoparticles (NP) co-doped with nitrogen and fluorine and irradiated with a violet LED light (LT).

METHODS

Bovine enamel-dentin disks adapted to artificial pulp chambers were randomly assigned to bleaching (n = 8/group): NC (negative control), NP, HP6, HP6 + LT, HP6 + NP, HP6 + NP + LT, HP35, HP35 + LT, HP35 + NP, HP35 + NP + LT, and commercial HP35 (COM). Color (ΔE00) and whiteness index (ΔWID) changes were measured before and 14 days after bleaching. The extracts (culture medium + diffused gel components) collected after the first session were applied to odontoblast-like MDPC-23 cells, which were assessed concerning their viability, oxidative stress, and morphology. The amount of HP diffused through the disks was determined. Data were analyzed by generalized linear models or Kruskal Wallis Tests (α = 5%).  RESULTS: HP6 + NP + LT exhibited ΔE00 and ΔWID higher than HP6 (p < 0.05) and similar to all HP35 groups. HP6 + NP + LT showed the lowest HP diffusion, and the highest cell viability (%) among bleached groups, preserving cell morphology and number of living cells similar to NC and NP. HP6 + LT, HP6 + NP, and HP6 + NP + LT exhibited the lowest cell oxidative stress among bleached groups (p < 0.05). HP35, HP35 + LT, and HP35 (COM) displayed the lowest cell viability.

CONCLUSION

HP6 achieved significantly higher color and whiteness index changes when incorporated with nanoparticles and light-irradiated and caused lower cytotoxicity than HP35 gels. The nanoparticles significantly increased cell viability and reduced the hydrogen peroxide diffusion and oxidative stress, regardless of HP concentration.

CLINICAL SIGNIFICANCE

Incorporation of co-doped titanium dioxide nanoparticles combined with violet irradiation within the HP6 gel could promote a higher perceivable and acceptable efficacy than HP6 alone, potentially reaching the optimal esthetic outcomes rendered by HP35. This approach also holds the promise of reducing cytotoxic damages and, consequently, tooth sensitivity.

A scanning electron microscope analysis on the effect of bleaching gel in combination with fluoro calcium phosphosilicate-based dentifrice on whitening of teeth and dentinal tubule occlusion - An in vitro study

Aim

The aim of this study is to investigate the use of 15% carbamide peroxide in combination with fluoro calcium phosphosilicate desensitizing dentifrice during bleaching to evaluate postoperative dentinal tubule occlusion.

Materials and Methods

Premolars which were extracted and bleached using 15% carbamide peroxide with fluoro calcium phosphosilicate dentifrice were used in this investigation, and the shade change was assessed. They were subsequently divided into sections and examined with scanning electron microscope. The quantity of open tubules, fully obstructed as well as moderately obstructed tubules, was recorded for each specimen. The statistical analysis of shade changes was conducted using the paired t-test. The tubule numbers were statistically evaluated after being assigned a mean and standard deviation.

Results

The mean values between test and control groups in completely blocked tubules are 81.370 ± 1.989 and 42.586 ± 11.316, respectively. In partially blocked tubules, the mean values were found to be 13.219 ± 1.747 and 32.264 ± 11.554, respectively. In open tubules, the mean values are 5.398 ± 1.260 and 25.149 ± 8.781. The mean values of shade comparison for test group and control group are 1.95 ± 2.78 and 3.40 ± 2.83, respectively.

Conclusions

According to the findings of the study, dentinal tubules were blocked when fluoro calcium phosphosilicate dentifrice was administered with 15% carbamide peroxide, but the bleaching process was unaffected. The potential clinical advantage of using a single paste system for both bleaching and desensitizing was also emphasized.

The decomposition rate and bleaching efficacy of in-office bleaching gels with different pHs: a randomized controlled trial

BACKGROUND

To evaluate the decomposition rate of active hydrogen peroxide (HP) and bleaching efficacy during in-office bleaching using high-concentration HP gels with different pHs.

METHOD

A randomized, parallel, double-blind controlled trial was conducted with 40 volunteers randomized into four groups (pH 5.4; pH 7.0; pH 7.7, and pH 8.0). During the first session in-office bleaching, approximately 0.01 g of the gel was collected and titrated with potassium permanganate to obtain the concentration of active HP and pH values were measured using an electrode. Bleaching efficacy was assessed using a spectrophotometer [∆Eab, ∆E00, and WID], Vita Classical and Vita Bleachedguide scales [∆SGU]. The decomposition rate of HP concentration and pH values change were calculated using ANOVA one-way. The bleaching efficacy was assessed using two-way repeated measures ANOVA. Tukey's test was applied as a post-hoc test (p < 0.05).

RESULTS

All gels experienced decreasing HP concentration over time. pH 5.4 gel showed greatest reduction after 50 min (p < 0.001). pH 8.0 and 7.7 gels remained stable; pH 5.4 remained acidic, while pH 7.0 turned acidic (p < 0.001). No significant difference in bleaching degree was observed among gels. They all showed a similar and clinically important color change after two clinical sessions, remained stable 1-month post-treatment (p > 0.05).

CONCLUSIONS

All bleaching gels kept at least 70% of their HP content after 50 min, suggesting that there is a surplus of HP. They provided similar whitening efficacy 1-month after bleaching.

PRACTICAL IMPLICATIONS

It is possible that lower HP concentrations may be equally effective in achieving desired results while reducing the potential for side effects.

CLINICAL TRIAL REGISTRY NAME

RBR-35q7s3v.

Tooth whitening: current status and prospects

As a safe, effective, economical, and convenient technique, tooth whitening is one of the most popular treatments for improving tooth discoloration. This review summarizes the theoretical and recent research developments in the classification and mechanisms of tooth discoloration, as well as the principles, agents, effects, and side effects of tooth whitening techniques. The aim is to provide a basis for the clinical treatment of tooth whitening techniques and to suggest possible new ideas for further research. The accepted mechanism of whitening is the redox reaction of oxides in the whitening reagent, and the whitening effect is remarkable. However, side effects such as tooth sensitivity and irritation of gum and other oral soft tissues can still occur. It is recommended that more monitoring be carried out in the clinic to monitor these side effects, and care should be taken to protect the soft tissues in the mouth during office whitening procedures. Furthermore, there is a need to develop new additives or natural whitening products to reduce the occurrence of side effects.

Effect of Various Vital Bleaching Systems on Clinical Outcomes and Patient Satisfaction

Objective To evaluate the clinical behavior of different bleaching products - the hydrogen peroxide (H2O2), carbamide peroxide (CP), and titanium dioxide bleaching systems. Methods Three bleaching systems with different concentrations (H2O2 15%, 38%, CP 15%, 35%, and titanium dioxide 20% H2O2) were used. Sixty participants with discolored teeth were enrolled and equally divided into six groups. Each group was rendered the assigned bleaching protocol against the control group, which received plain dentifrice polishing. Each case was evaluated immediately, two weeks, three months, six months, and one year after the bleaching treatment. The clinical evaluation was made for color change by (shade guide and digital images with L*a*b* parameters), tooth sensitivity, gingival irritation, and participants' satisfaction. Results All bleaching systems showed color improvement after bleaching regimens with significant effect showed by in-office titanium dioxide 20% H2O2 followed by 38% H2O2 with Δ=10.26 and Δ=6.52, respectively, when compared to other bleaching techniques. Higher sensitivity was recorded in group III with 50% of the participants reporting postoperative sensitivity. Higher gingival irritation was recorded in group IV (15% CP) where 60% of the patients reported gingival irritation. Thirty-five of the 60 participants (58.5%) recorded that the treatment whitened their teeth "moderately" and "a lot" while seven participants recorded "a slight" difference. There was a highly significant difference in participants' satisfaction between all bleaching groups (p < 0.05). Conclusion It is evident that there is a development of dental sensitivity and gingival irritation irrespective of the bleaching system used. The color assessment showed that the desired result can be achieved with variable levels of patient satisfaction with excellent overall results with the titanium dioxide system.

Low and high hydrogen peroxide concentrations of in-office dental bleaching associated with violet light: an in vitro study

OBJECTIVES

This study aims to assess hydrogen peroxide (HP) penetration within the pulp chamber, color change (CC), physical-chemical properties, and temperature using in-office different concentration bleaching gels with or without violet light.

MATERIALS AND METHODS

Fifty teeth were divided into five groups (n = 10) based on the HP concentration bleaching gels used (6% and 35%) and the used violet light (with or without). HP penetration within the pulp chamber was measured using UV-Vis. The CC was evaluated with a digital spectrophotometer. Initial and final concentration, and pH were measured through titration, and a Digital pHmeter, respectively. Temperature analyses were measured through a thermocouple. Statistical analysis included two-way ANOVA, Tukey's, and Dunnett's test (α = 0.05).

RESULTS

The presence of violet light did not affect the amount of HP within the pulp chamber, or the CC (p > 0.05). Greater penetration of HP was observed within the pulp chamber, as well as CC when using 35% HP (p < 0.05). The final concentration of both gels was lower than the initial concentration, regardless of the use of violet light (p < 0.05). The initial and final pH levels remained neutral and stable (p > 0.05). The pulp temperature increased when the gels were used in conjunction with violet light (p < 0.05).

CONCLUSIONS

Using violet light in conjunction with 6% or 35% HP does not alter the physical properties of the bleaching agents, the penetration of HP or enhance color change. However, an increase in temperature was observed when violet light was applied associated with bleaching gels.

CLINICAL RELEVANCE

While the simultaneous use of violet light with hydrogen peroxide 6% or 35% does not alter the material's properties, it also does not bring benefits in reducing hydrogen peroxide penetration and improving color change. Furthermore, the use of violet light increases pulp temperature.

Comparison of in-office and at-home bleaching techniques: An umbrella review of efficacy and post-operative sensitivity

Objectives

The objective of this umbrella review is to evaluate the efficacy and adverse effects of different teeth whitening techniques in-office (IO) and at-home (AH), regarding chromatic changes and teeth sensitivity.

Materials and methods

The search was carried out from several databases. The included studies were all systematic reviews with or without meta-analysis of RCT or quasi-RCT. The participants were patients that underwent external dental bleaching in permanent vital teeth. The interventions were in-office (IO) bleaching techniques and at-home (AT) bleaching techniques with different bleaching agents and concentrations.

Results

The search resulted in a total of 257 articles, and 28 SR were included in the qualitative analysis and nine in the quantitative analysis. There is no difference between in-office and at-home techniques in terms of color change (p = 0.95) and post-treatment sensitivity (p = 0.85). There is similarity risk and intensity of teeth sensitivity between AH and IO bleaching. IO bleaching with light-activated systems with low concentrations of bleaching agent showed similar results to IO bleaching techniques with high concentrated bleaching gels. With the application of the criteria of the AMSTAR 2 tool, the reviews were considered critically low to high.

Conclusions

There are no significant differences in terms of color change between the different bleaching techniques compared. Teeth sensitivity is always present regardless of the technique used. The use of light activation systems did not increase the intensity and risk of post-operative sensitivity.

At-home bleaching versus whitening toothpastes for treatment of tooth discoloration: a cost-effectiveness analysis

OBJECTIVES

This study aimed to analyze the cost-effectiveness of whitening toothpastes and at-home bleaching for the treatment of tooth discoloration.

METHODOLOGY

A cost-effectiveness economic analysis was conducted, and eight randomized clinical trials were selected based on the whitening agent product used: blue covarine dentifrices (BCD), hydrogen peroxide dentifrices (HPD), dentifrices without bleaching agents (CD, negative control), and 10% carbamide peroxide (CP10, positive control) for at-home bleaching. The consumer/patient perspective was adopted, macro-costing techniques were used and a decision tree model was performed considering the costs in the American and Brazilian markets. The color change evaluation (ΔE*ab) was used to calculate the effectiveness of tooth bleaching. A probabilistic analysis was performed using a Monte Carlo simulation and incremental cost-effectiveness ratios were obtained.

RESULTS

CP10 resulted in the highest cost-effectiveness compared to the use of dentifrices in both markets. In Brazil, HPD was more cost-effective than BCD and CD. In the US, the increased costs of HPD and BCD did not generate any whitening benefit compared to CD.

CONCLUSIONS

CP10 was more cost-effective than BCD and HPD for tooth bleaching from the perspectives of the Brazilian and American markets. Decision-making should consider the use of CP10 for treating tooth discoloration.

Effects of enamel moistening and repositioning guide color on tooth whitening outcomes: A clinical trial

This clinical trial investigated the effects of pre-application enamel moistening on the impact of a 37% carbamide peroxide whitener on tooth color changes and the influence of repositioning guide colors. Forty participants were randomly assigned to in-office tooth bleaching with either moistened enamel (experimental) or dry enamel (control). The whitener was applied for 45 min over two sessions. Tooth color was visually measured or assessed using a spectrophotometer with purple or green silicone guides. Tooth bleaching was assessed using CIE76 (ΔEab ) and CIEDE2000 (ΔE00 ) formulas and by whitening and bleaching index score changes. Moistening the enamel did not significantly affect tooth color. However, the guide color choice only impacted tooth color when measured instrumentally. At baseline, the green guide resulted in statistically significantly whiter teeth than the purple guide. Less pronounced differences in the b* coordinate between baseline and final measurements were found using the green guide. The green guide also produced lower ΔEab values and less change in indexes. In conclusion, moistening the enamel did not significantly impact tooth color changes. However, the repositioning guide color influenced the tooth bleaching measured instrumentally, except for ΔE00 .

Dental aesthetic perception of patients submitted to activated charcoal-based bleaching agents: A randomized clinical trial

OBJECTIVE

To evaluate the effects of activated charcoal-based products used in two presentation forms (powder or toothpaste), compared to 10 % carbamide peroxide and conventional toothpaste on aesthetic perception and psychosocial impact before and after treatment.

METHODS

Fifty-six participants were divided into 4 experimental groups (n = 14). Activated charcoal-based powder (PW); Activated charcoal-based dentifrice (AC); Conventional fluoride toothpaste (CD) and 10 % carbamide peroxide (CP). All products were used for 14 days. Psychosocial impact on dental esthetics (PIDAQ), oral health impact profile (OHIP- Esthetics) and orofacial esthetics scale (OES) questionnaires were applied before and after treatment. Descriptive and exploratory data analyses were performed and analyzed using linear mixed models for repeated measures over time considering significance level of α = 0.05.

RESULTS

For PIDAQ, the CP group showed significant decrease in psychological impact, aesthetic perception domains and overall score, while in the PW group, there was only a significant decrease in the psychological impact domain. Decrease in OHIP was observed for the functional limitation domain scores for treatments with CP and PW, in the psychological discomfort domain, decrease was observed for all groups, while for the OES questionnaire, significant increase in the color domain was observed for the CP group.

CONCLUSION

Activated charcoal-based products showed lower scores in all questionnaires when compared with carbamide peroxide; thus, charcoal-based products promoted lower impact on quality of life and aesthetic perception.

CLINICAL RELEVANCE

In this randomized clinical trial, charcoal-based OTC products had inferior quality of life and aesthetic perception results compared to conventional carbamide peroxide bleaching.

In vitro bleaching efficacy of violet LED associated with 10% hydrogen peroxide and 10% carbamide peroxide

BACKGROUND

This in vitro study evaluated the efficacy and the effect over the dental enamel surface of violet LED dental bleaching associated to different concentrations of carbamide and hydrogen peroxide.

METHODS

Human dental blocks (n = 100) were randomly distributed into 5 groups: 10% hydrogen peroxide (HP10), 10% carbamide peroxide (CP10), 10% hydrogen peroxide with violet LED (VHP10), 10% carbamide peroxide with violet LED (VCP10) and 35% hydrogen peroxide (HP35). The specimens were analyzed by Vickers microhardness test (n = 50) initially, immediately after and seven days after ending the bleaching protocol. For color analysis (n = 50), the specimens were evaluated for bleaching effectiveness (ΔE2000, ΔE1976) and whiteness index (ΔWID) with EasyShade spectrophotometer, before bleaching protocol and seven days after ending the bleaching protocol. The microhardness and color data were analyzed using one-way ANOVA with post-hoc Tukey test (α = 0.05).

RESULTS

The microhardness values showed difference among the investigated groups only immediately after the end of the dental bleaching (p < 0.05), with reduction for the groups HP35 (p < 0.01) and HP10 (p < 0.05), however the microhardness values were reestablished after seven days. Regarding the color changes, a difference between VHP10 and the others groups evaluated for ΔE2000 and ΔE1976 index was observed (p < 0.05). For ΔWID, there was no difference between the studied groups.

CONCLUSIONS

Violet LED associated with low concentration bleaching agents did not show a negative effect on dental enamel regarding the surface microhardness. All bleaching protocols were effective, therefore, perceptible to human eyes.

In-office dental bleaching in adolescents using 6% hydrogen peroxide with different application tips: randomized clinical trial

OBJECTIVE

Despite the availability of in-office bleaching gels with a 6% concentration of hydrogen peroxide (HP), these gels have not been evaluated in younger patients. They are commercially available with a tip, associated or not with a brush, where the tip with a brush spreads the gel over the entire surface to have a smaller thickness (thin layer) since the manufacturers indicate the application of a thin layer of gel. This randomized, split-mouth, double-blind clinical trial evaluated the efficacy of in-office bleaching with 6% HP in adolescents using different application tips, as well tooth sensitivity (TS) and aesthetic self-perception.

METHODOLOGY

Sixty participants were randomized for 6% HP self-mixing bleaching gel tip design: without brush and with brush. In-office bleaching was performed in 3 sessions of 50 minutes. Color change was evaluated using a digital spectrophotometer (ΔE ab , ΔE 00 , and ΔWI D ) and color guide (ΔSGU), the absolute risk and intensity of TS with a visual analogue scale and aesthetic self-perception with the oral aesthetic scale (a=0.05).

RESULTS

The groups achieved similar bleaching regardless of the application tip (p>0.05). However, only for ΔWI D , a significant mean difference (MD) was observed in the third week (MD 2.3; 95% CI 1.2 to 3.3; p < 0.001) and at one month (MD 1.6; 95% CI 0.6 to 2.6; p < 0.03) favoring the tip without brush. Regarding TS, 45% in the tip-without-brush group and 33% in the tip-with-brush group reported TS (odds ratio 0.61; 95% CI 0.29 to 1.28; p<0.02), with low TS intensity (MD 0.05; 95% CI -0.06 to 0.17; p>0.36). All patients reported improved aesthetic self-perception after bleaching (MD -1.3; 95% -1.8 to -0.9; p<0.001).

CONCLUSIONS

Regardless of the tip used bleaching with 6% HP achieved a bleaching efficacy and improved the aesthetic self-perception. However, a lower risk of TS for application using the tip with brush was observed.

Efficiency of Various Tubular Occlusion Agents in Human Dentin after In-Office Tooth Bleaching

The aim of this laboratory study was to investigate and compare the impact of five desensitizing techniques as a treatment fortooth sensitivity on the exposed dentin after an in-office tooth bleaching procedure. Thirty intact human molars were collected for this investigation. The specimens were obtained by transversely cutting 2.5 mm of the crowns, leading to exposure of the dentin. The specimens were cleaned in an ultrasonic bath and treated initially with EDTA gel 15% for 4 min and then with Opalescence Boost bleaching gel (40% H2O2) for two sets of 20 min. Then, the samples were randomly divided into six groups (n = 5) and received one of the following treatments: Group 1 (no treatment-control group), Group 2 (Emofluor gel-0.4% SnF2), Group 3 (MI Paste-CPP-ACPF), Group 4 (BioMinF paste-calcium phospho-fluoro-silicate), Group 5 (air-abrasion with ProSylc-Bioglass 45S5), and Group 6 (Er,Cr:YSGG laser). Subsequently, each sample was observed utilizing scanning electron microscopy (SEM) in order to detect the rate of occlusion of dentin tubules. SEM-EDS analysis revealed no occlusion of the dentin tubules in the control group, while Groups 2, 4, and 5 presented high effectiveness (>95% percentage of occluded tubules), and Groups 3 and 6 presented lower values (21.6 and 26.8%, respectively). It was concluded that althoughall the tested groups presented higher percentages of occlusion of the dentinal tubules compared to the control group, there were differences in effectiveness among them. The most effective treatments were the daily use of BioMinF paste and SnF2-containing gel, as well as air-abrasion with ProSylc powder.

Tooth color change promoted by different whitening toothpastes under alternate cycles of staining and brushing

OBJECTIVES

To compare the effect of whitening toothpastes with different mechanisms of action on discolored teeth subjected to additional staining/or not.

METHODS

One hundred twenty tooth specimens were stained for 14 days (staining broth under constant agitation and pH=7) and then allocated into the groups of toothpastes with different whitening ingredients (n=10): 1. Regular - Colgate Total 12 Clean Mint; 2. CLWI - Colgate Luminous White Instant (blue pigment); 3. CLWA - Colgate Luminous White Advanced Expert (hydrogen peroxide); 4. CLWAC - Colgate Luminous White Activated Charcoal (activated charcoal); 5. OB3D - Oral-B 3D WHITE Brilliant Fresh (abrasive); 6. TW - Teeth Whitening (charcoal powder). Specimens were submitted to two experimental models: A. Daily staining-toothbrush cycling: staining solution (5min), toothbrushing (45 strokes) and artificial saliva (3h), 2x/day, for 5days; B. Only toothbrushing (30.000 brushing strokes). Color change was determined with a spectrophotometer (CIEDE2000 and Whitening Index for Dentistry - WID) and statistically analyzed (α=0.05).

RESULTS

For both models, ΔE00 and Δa did not differ significantly between the whitening toothpastes and the regular. All groups showed a decrease in tooth yellowness (-Δb) and an increase in WID. Group Teeth Whitening exhibited a decrease in luminosity (-ΔL). In model A, Groups did not differ significantly from the Regular in terms of ΔL (p=0.35) and Δb (p=0.74). Groups CLWI and OB3D exhibited a decrease in luminosity. Reduced redness (-Δa) occurred only in Group CLWI. In Model B, Groups OB3D (p=0.021) and CLWA (p=0.001) exhibited higher change in luminosity than in Group Teeth Whitening. All exhibited increased redness (+Δa) and lightness (+ΔL), except the Regular, CLWAC and Teeth Whitening. Group OB3D had a significantly higher change in Δb than the Regular (p=0.021).

CONCLUSIONS

Irrespective of the mechanism of action, all toothpastes reduced tooth yellowness and promoted similar overall color change. Exposure of the teeth to additional staining during the toothbrushing cycles did not influence the effect of the whitening toothpastes.

CLINICAL SIGNIFICANCE

Whitening toothpastes should be tested in conditions that more closely simulate their use in a clinical scenario, in which alternate cycles of staining and brushing occur on a daily basis. However, even in such conditions, they were unable to promote a color change that differed from that of a regular toothpaste.

Evidence-based fact checking for selective procedures in restorative dentistry

OBJECTIVES

Similar to other dental specialties, there are many clinical procedures in restorative dentistry that may or may not be supported by good evidence. Thus, the effectiveness of these procedures is uncertain. The aim of this paper is to reduce this knowledge gap by critically inspecting selective procedures in restorative dentistry and exploring if these well-established or widely advocated treatment modalities are necessary for improving treatment outcomes based on the best available evidence.

MATERIALS AND METHODS

A MEDLINE search was conducted to identify research on selective procedures while focusing on clinical trials and systematic reviews. Due to their practical relevance in the decision-making process, cost-effectiveness analyses were also included.

RESULTS

Mixed results were identified regarding the included interventions. Some procedures had adequate evidence supporting them while others were mostly based on beliefs.

CONCLUSIONS

A critical review of the available literature indicates that some common restorative procedures lack adequate support from high-quality research evidence.

CLINICAL RELEVANCE

This paper attempts to highlight the need to critically examine the scientific validity of traditional knowledge and techniques through the context of current research evidence. This will not only help generate consensus between educators, clinicians, and researchers regarding restorative procedures but will also lead to improved patient care and outcomes.

Influence of smoking on the effectiveness of tooth whitening: a systematic review

OBJECTIVES

Perform a systematic review to evaluate the influence of smoking on the effectiveness of tooth whitening (TW) and to analyze whether tooth sensitivity is different between smokers and non-smokers.

MATERIALS AND METHODS

A systematic review modeled according to the PRISMA guidelines was conducted. PubMed, Embase, Web of Science, Cochrane, Scopus, and OpenGrey databases were searched for related clinical trials. The population, exposure, comparison, outcomes (PECO) was individuals who had TW performed, smoking individuals, non-smoking individuals, and effectiveness of TW, respectively. Risk of bias was assessed with the ROBINS-I tool, and data from included studies were extracted by two researchers independently. The certainty of the evidence was evaluated using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) approach.

RESULTS

Five studies were selected for qualitative analysis. The ROBINS-I tool classified 3 studies as having a moderate risk of bias, one study as having a serious risk of bias, and one with a critical risk. GRADE performed only for color change results and showed a low certainty of evidence. Limited evidence suggests that effectiveness of TW between smokers and non-smokers is similar. The tooth sensitivity also does not seem to be influenced by smoking. Due to the heterogeneity of the data, a meta-analysis could not be performed.

CONCLUSIONS

Effectiveness of TW between smokers and non-smokers is comparable. The tooth sensitivity also does not seem to be influenced by smoking.

CLINICAL RELEVANCE

The effectiveness of bleaching among smokers and non-smokers appears to be similar. Tooth sensitivity during TW also appears not to be influenced by smoking.

Bleaching efficacy and quality of life of different bleaching techniques - randomized controlled trial

OBJECTIVES

To evaluate bleaching efficacy and oral health-related quality of life (ORHQoL) of three bleaching systems with similar hydrogen peroxide (HP) concentration for up to 6 months post-treatment.

MATERIALS AND METHODS

A randomized controlled trial was designed with three parallel groups: group A - in-office 6% HP paint-on varnish; group B - at-home 6% HP with adaptable tray; group C - at-home 16% carbamide peroxide with custom tray. At three different stages (baseline, after bleaching, and 6-month follow-up), ORHQoL was evaluated by the OHIP-14 questionnaire and tooth color of the upper canines and central incisors were measured by two shade guides and a spectrophotometer (measuring CIE L*a*b* with respective color/whiteness differences - ΔE00/ΔWID). Results were presented as mean and 95% confidence intervals and statistical tests were performed appropriately, considering a significance level of α = 0.05.

RESULTS

All groups presented significant color differences (P < 0.05) between all stages, with ΔE00/ΔWID surpassing the perceptibility threshold in 98% cases, with group C's results being significantly (P < 0.05) higher when compared to other groups, although with significantly (P < 0.05) higher values of color relapse. Significative ORHQoL improvements (P < 0.05) were detected after bleaching in a global analysis with no differences between techniques.

CONCLUSIONS

All techniques presented bleaching efficacy, color stability, and improvements in ORHQoL up to 6 months post-treatment.

CLINICAL SIGNIFICANCE

Clinicians may consider both at-home and in-office bleaching techniques with 6% HP to attain long-lasting satisfactory clinical results while producing positive changes in ORHQoL.

Pro-inflammatory mediators expression by pulp cells following tooth whitening on restored enamel surface

This paper aimed to assess the influence of adhesive restoration interface on the diffusion of hydrogen peroxide (H₂O₂), indirect toxicity, and pro-inflammatory mediators expression by odontoblast-like cells, after in-office tooth whitening. Dental cavities prepared in bovine enamel/dentin discs were adhesively restored and subjected or not to hydrolytic degradation (HD). A whitening gel with 35% H₂O₂ (WG) was applied for 45 min onto restored and non-restored specimens adapted to artificial pulp chambers giving rise to the groups: SD- intact discs (control); SD/HP- whitened intact discs; RT/HP- restored and whitened discs; and RT/HD/HP- restored and whitened discs subjected to HD. The extracts (culture medium + WG components diffused through enamel/dentin/restoration interface) were collected and applied to odontoblast-like MDPC-23 cells. The study evaluated the amount of H₂O₂ in the extracts, as well as the cell viability (CV), cell morphology (CM), and gene expression of inflammatory mediators (TNF-α and COX-2) by the pulp cells exposed to the extracts (ANOVA and Tukey tests; 5% significance). All whitened groups presented lower CV than SD (control; p<0.05). The highest CV reduction and gene expression of TNF-α and COX-2 was observed in the RT/HD/HP group in comparison with SD/HP and RT/HP (control; p<0.05). CM alterations occurred in all whitened groups. The intensity of these cell side effects was directly related with the amount of H₂O₂ in the extracts. We concluded that adhesive restoration of dental cavity increases the H₂O₂ diffusion after in-office whitening, enhancing the indirect toxicity of this therapy and trigger pro-inflammatory overexpression by MDPC-23 cells.

Strategy for reducing cytotoxicity and obtaining esthetic efficacy with 15 min of in-office dental bleaching

OBJECTIVES

Evaluate in vitro the esthetic efficacy and cytotoxicity of a bleaching gel containing 35% hydrogen peroxide (BG-35%H₂O₂), applied for different time intervals, on enamel coated or not with polymeric biomaterials.

MATERIALS AND METHODS

Nanofiber scaffolds (NSc) and a primer catalyst (PrCa) were used to coat the bovine enamel/dentin discs before the application of BG-35%H₂O₂, according to the following groups: G1-negative control (NC, without treatment); G2, G3, and G4-BG-35%H₂O₂ applied for 3 × 15, 2 × 15, and 15 min; G5, G6, and G7-BG-35%H₂O₂ applied on enamel coated with NSc and PrCa for 3 × 15; 2 × 15, and 15 min, respectively. The culture medium with components of gel diffused through the discs was applied on MDPC-23 cells, which were evaluated regarding to viability (VB), integrity of the membrane (IM), and oxidative stress (OxS). The quantity of H₂O₂ diffused and esthetic efficacy (ΔE/ΔWI) of the dental tissues were also analyzed (ANOVA/Tukey; p < 0.05).

RESULTS

Only G7 was similar to G1 regarding VB (p > 0.05). The lowest value of H₂O₂ diffusion occurred in G4 and G7, where the cells exhibited the lowest OxS than G2 (p < 0.05). Despite G5 showing the greatest ΔE regarding other groups (p < 0.05), the esthetic efficacy observed in G7 was similar to G2 (p > 0.05). ΔWI indicated a greater bleaching effect for groups G5, G6, and G7 (p < 0.05).

CONCLUSION

Coating the dental enamel with polymeric biomaterials reduced the time and the cytotoxicity of BG-35%H₂O₂.

CLINICAL SIGNIFICANCE

Coating the dental enamel with polymeric biomaterials allows safer and faster BG-35%H₂O₂ application.

Is the use of a potassium nitrate dentifrice effective in reducing tooth sensitivity related to in-office bleaching? A randomized triple-blind clinical trial

OBJECTIVE

The aims of this study were to evaluate whether the use of a dentifrice containing 5% potassium nitrate (KNO₃ ) prior to and during in-office dental bleaching reduces bleaching-induced tooth sensitivity and affects bleaching efficiency.

MATERIALS AND METHODS

Thirty-eight individuals were randomly distributed into two groups (n = 19). The experimental group performed toothbrushing using a dentifrice containing 5% KNO₃ , one week before treatment and before the first and second bleaching sessions. In the control group, a placebo dentifrice without KNO₃ was applied as described for the first group. Tooth sensitivity was recorded on visual analog scales (VAS) and numeric rating scales (NRS) immediately and up to 48 h after bleaching sessions. Color change at different time intervals, was evaluated with shade guide units (∆SGU) and a digital spectrophotometer (∆E CIELab 1976 and CIEDE2000) at baseline and 7, 15, and 30 days post-bleaching. Mann-Whitney test and t-test were used to evaluate TS intensity for NRS and VAS scales, respectively, and T-test was used for color difference evaluation.

RESULTS

No significant difference in tooth sensitivity's absolute risk and intensity were observed between tested groups in any evaluated treatment time for NRS (p = 0.91) or VAS scales (p = 0.48). T-test showed no significant difference in both ∆E and ∆SGU tooth color among the experimental and control groups during the different evaluation times (p = 0.27).

CONCLUSION

The use of a dentifrice containing 5% KNO₃ does not prevent post-operatory tooth sensitivity but allows the same whitening efficiency as a regular dentifrice.

CLINICAL SIGNIFICANCE

The use of a dentifrice-containing KNO₃ did not prevent bleaching-induced tooth sensitivity when high-concentrated hydrogen peroxide was used for in-office bleaching.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2020 professional literature in restorative dentistry to inform busy dentists regarding noteworthy scientific and clinical progress over the past year. Each member of the committee brings discipline-specific expertise to this work to cover this broad topic. Specific subject areas addressed include prosthodontics; periodontics, alveolar bone, and peri-implant tissues; implant dentistry; dental materials and therapeutics; occlusion and temporomandibular disorders (TMDs); sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence day-to-day dental treatment decisions with a keen eye on future trends in the profession. With the tremendous volume of dentistry and related literature being published today, this review cannot possibly be comprehensive. The purpose is to update interested readers and provide important resource material for those interested in pursuing greater detail. It remains our intent to assist colleagues in navigating the extensive volume of important information being published annually. It is our hope that readers find this work useful in successfully managing the dental patients they encounter.

Efficacy and tooth sensitivity of at-home bleaching in patients with esthetic restorations: a randomized clinical trial

OBJECTIVES

This study aims to evaluate the color change and tooth sensitivity (TS) caused by at-home bleaching in patients with sound and with restored teeth.

METHODS

Forty patients were selected according to the inclusion and exclusion criteria and divided into two groups: So (patients with six caries-free maxillary anterior teeth) and Re (patients with at least one restoration in the six maxillary anterior teeth). Both groups were bleached with 10% carbamide peroxide (CP) at-home bleaching. The color change (CIELab [ΔE*_ab], CIEDE00 [ΔE₀₀], and whiteness index [∆WI_D]) were assessed using a spectrophotometer at baseline, 2 weeks, and 1 and 3 months after bleaching. Patients recorded their TS using a numeric rating scale (0-4). Data of color change were submitted to Student's T-test. The absolute risk and intensity of TS were compared using Fisher's and the Mann-Whitney tests, respectively (α = 0.05).

RESULTS

Higher ΔE*_ab, ΔE₀₀, and ∆WI_D values were observed for So in relation to Re after all recall rate (p < 0.0001). No significant differences were observed regarding of bleaching-induced TS (p > 0.9).

CONCLUSIONS

At-home dental bleaching with 10% CP generated the same pattern of TS in patients with or without restorations. However, in patients with restored teeth, it produced a lower color change after 2 weeks of bleaching.

CLINICAL SIGNIFICANCE

After 2 weeks of at-home bleaching, a lower whitening effect was observed in patients with anterior restorations when compared with patients with sound teeth.

TRIAL REGISTRATION

ClinicalTrials.gov identifier RBR-52j6gmg.

Influence of Hydrogen Peroxide on Mineralization in Dental Pulp Cells: A Systematic Review

Background: Dental bleaching agents show the ability to permeate through dental hard tissues, which may lead to pulp tissue changes. This systematic review (PROSPERO register: CRD42020213767) is aimed at understanding the effects of bleaching agents on the process of mineralization of the pulp tissue.

Methods: Only in vitro studies evaluating the influence of hydrogen peroxide (HP) on mineralization in dental pulp cells were included. Studies without a non-bleached control group or cells after co-treatment with a bleaching agent other than HP and/or carbamide peroxide were excluded. The primary outcomes evaluated were alkaline phosphatase (ALP) activity and mineralized nodule deposition. The mineralization markers analysis in dental pulp cells and the cell viability were considered secondary outcomes. Two independent authors conducted a systematic search (PubMed/MEDLINE, Scopus, Embase, Cochrane Library, and OpenGrey until January 2021) with no language restrictions and performed data extraction. The quality assessment was appraised according to a modified Joanna Briggs Institute critical appraisal checklist.

Results: The search resulted in 473 studies, and 11 were considered eligible. Overall, a reduction in the process of mineralization was observed among pulp cells after bleaching. A reduction in the ALP activity was reported in the mostly bleached groups using different protocols and analysis periods of nine studies. Regarding mineralized nodule deposition, 6 studies reported a significant reduction from 7 to 21 days among bleached groups. Of those three studies that investigated other mineralization markers, two found a reduction in the expression of dentin matrix acidic phosphoprotein (DMP)-1, dentin sialophosphoprotein (DSPP), and matrix extracellular phosphoglycoprotein (MEPE) among some bleaching gel concentrations. In contrast, one study showed a greater expression of osteopontin (OPN) and osteocalcin (OCN) in 100 μmol/L HP after 5 or 10 min of exposure, and another study showed significant induction of DSPP in concentrations of up to 0.5 mmol/L HP.

Conclusion: Especially, high concentrations of bleaching gel reduce the potential of mineralization in pulp cells in in vitro studies; however, different HP concentrations, bleaching protocols, and analysis periods can influence this outcome.

A meta-analysis of ozone effect on tooth bleaching

This systematic review assessed the effectiveness of ozone (O₃) in the color change of in-office tooth bleaching in vital teeth (TB) and the sensitivity control. Only randomized controlled clinical trials were included. Seven databases were used as primary search sources, and three additional sources were searched to capture the "grey literature" partially. The JBI tool was used to assess the risk of bias. TB was assessed using the ΔELab color change metric comparing tooth color pre- and post-bleaching. We meta-analyzed the ΔELab estimates per method and calculated the absolute standardized mean difference using random-effect models. The GRADE approach assessed the certainty of the evidence. The ΔELab estimates ranged from 1.28 when the O₃ was used alone to 6.93 when combined with hydrogen peroxide (HP). Two studies compared O₃ and HP alone, but their TB was similar (SMD = - 0.02; 95%CI: - 0.54; 0.49). The bleaching effectiveness for the combination of O₃ + HP compared to HP was similar (SMD = 0.38; 95%CI: - 0.04; 0.81). Thus, based on the available literature, our findings suggest that O₃ is not superior to the conventional technique using HP on the change of tooth color. The O₃ did not present sensitivity when used alone. When O₃ was used in combination with HP, patients reported hypersensitivity only when O₃ was applied before HP, i.e., no sensitivity was perceived when O₃ was applied after HP.

A Comparative Evaluation of Nanohydroxyapatite-Enriched Hydrogen Peroxide Home Bleaching System on Color, Hardness and Microstructure of Dental Enamel

This study aimed to evaluate two hydrogen peroxide (HP)-based at-home bleaching systems in order to analyze whether nano-hydroxyapatite (nHA) addition may represent a reliable and safe solution for tooth whitening without altering dental microstructure and hardness. Human third molars (N = 15) were treated with two bleaching agents, one containing 6%HP (6HP) and the other 6% HP nHA-enriched (6HP-nHA) with average particle diameter ranging from 5-20 nm. Their effects on enamel were assessed using a spectrophotometer, Vickers microhardness (VMH) test and Scanning Electron Microscopy (SEM), comparing the treated groups with the non-treated control group (CTR). Color analysis revealed improvement in whiteness in both groups compared to CTR. VMH test results showed no differences among the groups. SEM analysis highlighted no evident changes in the enamel microstructure of tested groups compared to CTR. At high magnification, in 6HP group, a slight increase in irregularities of enamel surface morphology was observed, while 6HP-nHA group displayed removal of the aprismatic layer but preservation of the intact prismatic structure. These results suggest that the 6HP-nHA agent may be recommended to provide reliable whitening treatment, without damaging the enamel micromorphology and hardness.

Impact of tooth bleaching on oral health-related quality of life in adults: A triple-blind randomised clinical trial

OBJECTIVE

To investigate the impact of tooth bleaching on oral health-related quality of life (OHRQoL) in adults using a randomised clinical trial comparing at-home and in-office bleaching.

METHOD

A total of 130 individuals were randomly allocated to two groups (n = 65) according to the type of treatment. At-home treatment was performed using 10 % carbamide peroxide (2 h/day; 3 weeks) and an in-office placebo, while 35 % hydrogen peroxide was used for in-office (1/week; 3 weeks) and an at-home placebo. Colour was assessed using the CIELAB system using a digital spectrophotometer. Objective and subjective colour change was estimated by calculating CIEDE2000 (ΔE00) and shade guide units (ΔSGU), respectively. The OHRQoL was measured using the Brazilian version of the Oral Health Impact Profile (OHIP-14). All assessments were performed at baseline and after 21 days. For bivariate analysis, the chi-square test, Student's t-test, and Wilcoxon test were used. The effects of OHRQoL were assessed using distribution-based responsiveness.

RESULTS

Objective colour change was observed at home (p = 0.033), in comparison to in-office (p = 0.429). Mean OHIP-14 scores were similar between groups at baseline (p = 0.368) and after treatment (p = 0.695). Bleaching had a moderate positive effect on the OHRQoL of adults, especially with respect to the psychological discomfort domains, social disability, and total OHIP-14 score. The perception of tooth sensitivity in the group that received at-home treatment was negatively associated with OHRQoL (p = 0.037).

CONCLUSION

The bleaching agents were highly effective and demonstrated a moderate influence on the patients' aesthetic perception and psychosocial impact.

In-office bleaching with low/medium vs. high concentrate hydrogen peroxide: A systematic review and meta-analysis

OBJECTIVE

To answer the following research question: "Dolow/medium hydrogen peroxide (HP) concentrations used for in-office bleaching in patients with permanent dentition have similar color change and bleaching sensitivity (BS) to high HP concentrations?"

DATA

Randomized controlled trials that compared low/medium vs. high concentrate HP were included. The risk of bias (RoB) was evaluated using the Cochrane Collaboration tool. Meta-analyses were conducted for color change (ΔE*ab, ΔSGU/SGU), risk, and intensity of BS, using the random-effects model. Heterogeneity was assessed with the Cochrane Q test, I² statistics, and prediction interval. The GRADE assessed the certainty of the evidence.

SOURCES

Search was performed in PubMed, Cochrane Library, BBO, LILACS, Scopus, Web of Science and grey literature on 15th September 2018 (updated on 13th May 2020).

STUDY SELECTION

25 studies remained. Five were at low RoB; thirteen were at unclear RoB, and seven were at high RoB. The risk of having BS was, on average, 33 % lower (RR = 0.67; 95 % CI 0.51 to 0.86) for low/medium concentrate HP than high HP. No significant difference in color change was detected among groups, except from the subgroup low vs. high HP for the immediate color change, but this difference is not clinically relevant. The certainty of evidence for color change was low and very low, and moderate for the BS.

CONCLUSIONS

Low and medium hydrogen peroxide concentrate products for in-office bleaching have lower risk and intensity of bleaching sensitivity than the high concentrate hydrogen peroxide group, with no difference in color change efficacy.

CLINICAL SIGNIFICANCE

The use of low concentrate hydrogen peroxide products may produce the same color change efficacy with the bonus of having lower risk and intensity of bleaching sensitivity. However, the ideal concentration at which this occurs is yet unknown and deserves further investigations. No funding. PROSPERO CRD42018108266.