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.

Impact of the in-office bleaching gels pH on tooth sensitivity in combined bleaching techniques: a randomized clinical trial

OBJECTIVES

This randomized, parallel, single-blind clinical trial evaluated tooth sensitivity (TS), efficacy, gingival irritation (GI), aesthetic self-perception, and psychosocial impact of combined bleaching using in-office bleaching agents with different pHs.

MATERIALS AND METHODS

160 participants were randomized into two groups (n = 80) with 35% hydrogen peroxide in-office bleaching gels: Whiteness HP Maxx (acidic, unstable pH) and Whiteness HP Automixx Plus (neutral, stable pH). In-office bleaching was performed in one session: HP Maxx (3 applications of 15 min) and HP Automixx Plus (1 application of 50 min). Both groups then received at-home bleaching with 10% carbamide peroxide for 4 h daily for two weeks. TS and GI were assessed using Visual Analogue Scales. Color change was measured with a spectrophotometer and color guides. Aesthetic self-perception and psychosocial impact were evaluated using three scales: Orofacial Aesthetics Scale, Oral Health Impact Profile, and Psychosocial Impact Questionnaire of Dental Aesthetics.

RESULTS

The risk and intensity of TS significantly favored the neutral and stable pH gel for both in-office (p < 0.001) and combined treatments (p < 0.004). Both groups achieved significant whitening (p > 0.37). No difference in GI risk or intensity was found (p > 0.11). All aesthetic and psychosocial scales showed significant improvement post-treatment (p < 0.05).

CONCLUSION

Using a gel with neutral and stable pH during in-office bleaching reduces the risk and intensity of TS without compromising whitening efficacy.

CLINICAL RELEVANCE

Combining at-home and in-office bleaching with a neutral, stable gel reduces TS risk and intensity while ensuring optimal whitening results and patient comfort.

Evaluation of the Effectiveness of Different Types of Professional Tooth Whitening: A Systematic Review

BACKGROUND/OBJECTIVES

Tooth whitening is a cosmetic dental treatment that improves the color of natural teeth, making them whiter and brighter; this review aimed to evaluate the greater effectiveness of in-office, at-home, and combined bleaching with hydrogen or carbamide peroxide, also in relation to possible relapses and side effects (tooth sensitivity).

METHODS

A literature search has been carried out through electronic databases, PubMed/MEDLINE, and Cochrane Library, focused on the use of the effectiveness of in-office, at-home, and combined dental bleaching. This review has been registered on PROSPERO (ID613248).

RESULTS

30 articles have been included. Most of the studies did not find any more effective treatment than the proposed treatments; all types of bleaching have been shown to be effective in changing color; in the studies that have compared in-office and at-home bleaching, there was a lower recurrence of treatment with the use of the at-home trays with carbamide peroxide gel. There were no clear positions regarding tooth sensitivity, which would appear to be higher in professional in-office and combined dental bleaching.

CONCLUSIONS

Bleaching is an effective treatment for the change of color of the tooth regardless of the type used (concentrations, type of gel, and duration of sessions), although, at home, it would seem to be more effective over time. It is, however, a clinical feature that may give a risk of tooth sensitivity after treatment.

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.

The Effect of Positioning Guide Color on Shade Measurements Using a Clinical Spectrophotometer

The purpose of this study was to investigate the influence of the color of positioning guides on the CIEL*a*b* color coordinates of ceramic, resin composite and bovine tooth surfaces measured by a clinical spectrophotometer. Positioning guides (n=10) in different colors (translucent, purple, yellow, green and, blue) were made for each surface (ceramic, resin composite and bovine tooth). The CIEL*a*b* color coordinates were measured with the positioning guides and with no positioning guide (control group). The ΔL*, Δa*, Δb*, ΔE*ab, and ΔE00 were calculated between the control group and the different groups. The CIEL*a*b* color coordinates were analyzed by one-way ANOVA followed by the post-hoc Tukey test (α=0.05). Color differences were interpreted using the 50:50% perceptibility and acceptability visual thresholds. Positioning guides with different colors presented significant differences for all surfaces and color coordinates. ΔE*ab, and ΔE00 mean values for all surfaces and positioning guide colors exceeded the acceptability visual thresholds, except for the bovine tooth surface measured with the green positioning guide. The shade measurement was affected by the color of the positioning guides regardless of the surface that was evaluated.

Evaluating color change and hydrogen peroxide penetration in human and bovine teeth through in-office bleaching procedures

OBJECTIVE

Assess color alteration and hydrogen peroxide (HP) penetration in human and bovine teeth using various in-office bleaching protocols with different application times.

MATERIALS AND METHODS

Thirty healthy human premolars and 30 healthy bovine incisors were divided into five groups and subjected to different bleaching protocols: 2 × 15 min, 1 × 30 min, 2 × 20 min, or 1 × 40 min, with a control group for each tooth type. All teeth were treated with 35% HP gel. Color alteration was measured using digital spectrophotometry before and 1 week after bleaching. HP concentration within the pulp was determined via UV-Vis spectrophotometry. Statistical analysis included one-way ANOVA, Tukey's, and Dunnett's tests (α = 0.05).

RESULTS

All groups exhibited significant color alteration, with no statistically differences among them (p > 0.05). However, significant differences were observed when compared with their respective control groups (p < 0.05). HP penetration into the pulp was evident in all bleached teeth compared to the control groups (p < 0.05), with the 2 × 20 group showing the highest HP levels within the pulp cavity, irrespective of tooth type (p < 0.05).

CONCLUSION

A simplified 1 × 30-min protocol can be recommended as it effectively maintains color alteration and HP penetration, irrespective of whether human or bovine teeth.

CLINICAL SIGNIFICANCE

This study suggests that an in-office dental bleaching protocol using a 1 × 30-min session is recommended, as it ensures both effective color change and no increase in the amount of HP penetration.

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.

Effect of the type of application tip for 35% hydrogen peroxide on bleaching efficacy and tooth sensitivity: A randomized clinical trial

OBJECTIVES

Evaluate the bleaching efficacy (BE) and tooth sensitivity (TS) of in-office bleaching using different application tips.

METHODS

Forty-eight participants were selected (split-mouth), one to receive bleaching with an attached brush tip and one with a conventional tip. The procedure was performed with Whiteness Automixx Plus 35%. The BE was evaluated at the beginning, weekly, one and 12 months post-bleaching with a Vita Easyshade spectrophotometer (ΔE*ab, ΔE00, and WID) and with Vita classical A1-D4 and Vita Bleachedguide shade guides units (ΔSGU). Absolute risk and intensity of TS were recorded using the Visual Analogue Scale. The equivalence of BE was analyzed using the two one-sided t-tests for paired samples. The absolute risk of TS was evaluated using the McNemar test, and the TS intensity was measured with the paired t test (α = 0.05).

RESULTS

The equivalence of BE was observed for both groups in all color evaluations (p > 0.05). A lower absolute risk and intensity of TS were observed for the attached brush tip when compared with the conventional tip (p < 0.003 and p < 0.0001).

CONCLUSION

Using an attached brush tip showed the same BE as a conventional tip. However, for the attached brush tip, there was a reduction in TS.

CLINICAL SIGNIFICANCE

The applicator-attached brush tip is recommended for in-office dental bleaching, because of the possible reduction in risk and intensity of TS.

Bleaching efficacy of in-office dental bleaching with different application protocols: a single-blind randomized controlled trial

OBJECTIVE

This randomized controlled trial aimed to evaluate the equivalence in the color change, adverse effects, self-perception (AS) and the impact on oral condition (IO) of participants submitted to different application protocols of in-office dental bleaching.

MATERIALS AND METHODS

165 participants were bleached with a 35% hydrogen peroxide gel (Total Blanc Office One-Step, DFL), according to the following protocols: (1) 2 applications of 20-min each (2 × 20 min); (2) 1 × 40-min and; (3) 1 × 30-min. The color change was evaluated with the Vita Easyshade spectrophotometer, Vita Classical and Vita Bleachedguide scales. The intensity and risk of tooth sensitivity (TS) and gingival irritation (GI) were recorded using a 0-10 visual analogue scale (VAS). AS and IO was assessed before and after the bleaching procedure using the Orofacial Aesthetic Scale and Oral Health Impact Profile-14, respectively.

RESULTS

Equivalent color change were observed (p < 0.001), with no significant difference between groups. The group 2 × 20 min presented the highest risk of TS (76%, 95% CI 63 to 85), compared to the 1 × 30 min (p < 0.04). The intensity of TS and GI and the risk of GI was similar between groups (p > 0.31). Irrespectively of the group (p = 0.32), significant improvements were observed for all items of AS and IO after bleaching (p < 0.02).

CONCLUSIONS

The 1 × 30 min protocol produced equivalent color change to the other bleaching protocols with reduced risk of TS and shorter application time.

CLINICAL RELEVANCE

A more simplified application regimen of a single application of 30 min yields effective bleaching and patient satisfaction while minimizing undesirable side effects and improving patient satisfaction.

In-office dental bleaching in adolescents using 6% hydrogen peroxide with and without gingival barrier: a randomized double-blind clinical trial

BACKGROUND

At low concentrations used for in-office bleaching gels, such as 6% HP, gingival barrier continues to be performed. If we take into account that, in the at-home bleaching technique, no barrier is indicated, it seems that the use of a gingival barrier fails to make much sense when bleaching gel in low concentration is used for in-office bleaching.

OBJECTIVE

This double-blind, split-mouth, randomized clinical trial evaluated the gingival irritation (GI) of in-office bleaching using 6% hydrogen peroxide (HP) with and without a gingival barrier in adolescents, as well as color change and the impact of oral condition on quality of life.

METHODOLOGY

Overall, 60 participants were randomized into which side would or would not receive the gingival barrier. In-office bleaching was performed for 50 minutes with 6% HP in three sessions. The absolute risk and intensity of GI were assessed with a visual analogue scale. Color change was assessed using a digital spectrophotometer and color guides. The impact of oral condition on quality of life was assessed using the Brazilian version of the Oral Health Impact Profile (α=0.05).

RESULTS

The proportion of patients who presented GI for the "with barrier" group was 31.6% and for the "without barrier" group, 30% (p=1.0). There is an equivalence for the evaluated groups regarding GI intensity (p<0.01). Color change was detected with no statistical differences (p>0.29). There was a significant impact of oral condition on quality of life after bleaching (p<0.001).

CONCLUSIONS

The use or not of the gingival barrier for in-office bleaching with 6% HP was equivalent for GI, as well as for bleaching efficacy, with improvement in the impact of oral condition on quality of life.

Bleached enamel reversal using grape seed extract, green tea, curcumin-activated photodynamic therapy, and Er: YAG on microleakage and bond integrity of composite material bonded to the enamel surface

AIMS

Bleached enamel reversal using antioxidants sodium ascorbate (SA), Green tea extract (GTE), grape seed extract (GSE), Curcumin photosensitizer (CP) and Er: YAG laser on the adhesive strength and marginal leakage of composite material bonded to the bleached enamel surface.

MATERIALS AND METHODS

Enamel surface of hundred and twenty sound human first premolar teeth was cleansed using pumice and bleached with 35 % hydrogen peroxide. The samples were randomly divided into 5 groups based on the antioxidants used. n = 20 Group 1 (Control): No antioxidant agent, Group 2: 10 % SA solution, Group 3: 6.5 % GSE, Group 4: 5 % GTE, Group 5: Er: YAG laser and Group 6: CP. Following reversal, the composite was built and cured for 40 s. All the specimens were stored in distilled water at room temperature for 1 day. Microleakage, SBS, and failure mode were analyzed. Kolmogorov-Smirnov test, one-way analysis of variance, and Tukey's multiple post hoc test were used to analyze the data statistically.

RESULTS

Group 2 (SA) (20.11 ± 5.79 nm) exhibited minimum value of microleakage and highest SBS (10.22 ± 1.62 MPa). Whereas, Group 1 (No antioxidant agent) displayed maximum scores of marginal leakage (28.11±8.89 nm) and lowest SBS (7.02 ± 1.22 MPa).

CONCLUSION

CP, GTE and GSE can be used as a potential alternative to the commonly used SA solution to reverse the negative impact of bleaching on the enamel surface. The use of reversal agents CP, GTE and GSE improves bond values with a decrease in microleakage scores However, future studies are still warranted to conclude the outcomes of the existing study.

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.

The effect of ascorbic acid and cranberry on the bond strength, surface roughness, and surface hardness of bleached enamel with hydrogen peroxide and zinc phthalocyanine activated by photodynamic therapy

AIM

To evaluate the effect of different bleaching methods 40% (hydrogen peroxide) HP and Zinc Phthalocyanine (ZP) activated by photodynamic therapy (PDT) with the utilization of diverse procedures of reversal (10% ascorbic acid and 6% cranberry solution) on bond values, surface microhardness and surface roughness of bleached enamel surface.

MATERIAL AND METHODS

An aggregate of 60 extracted human mandibular molars was gathered and the buccal surface of each specimen was exposed to 2 mm of enamel surface for bleaching with chemical and photoactivated agents with the use of reversal solutions. Specimens were divided into six groups (n = 10) at random- Group 1: samples bleached with 40% HP with 10% ascorbic acid (reversal agent), group 2: ZP activated by PDT with 10% ascorbic acid (reversal agent), group 3: 40% HP with 6% cranberry solution as a reversal agent, group 4: ZP activated by PDT with 6% cranberry solution, group 5: 40% HP and group 6: ZP activated by PDT with no reversal agents. Resin cement restoration was performed via etch and rinse technique and SBS was estimated by using the universal testing machine, SMH by using Vickers hardness tester, and Ra by stylus profilometer. Statistical analysis was executed using the ANOVA test and the Tukey multiple tests (p<0.05).

RESULTS

Enamel surface bleached with 40% HP reversed with 10% ascorbic acid displayed the highest SBS while 40% HP with no reversal agent use showed the least SBS. For SMH, ZP activated by PDT when applied on the enamel surface and reversed with 10% ascorbic acid showed the highest SMH while when bleached with 40% HP and reversed with 6% cranberry solution showed the least SMH value. For Ra, Group 3: samples bleached with 40% HP with 6% cranberry solution as reversal agent showed the highest Ra value while bleaching of enamel surface with ZP activated by PDT with 6% cranberry displayed the least Ra value.

CONCLUSION

Bleached enamel surface with Zinc Phthalocyanine activated by PDT with the application of 10% ascorbic acid as reversal solution has demonstrated the highest SBS and SMH with acceptable surface roughness for bonding adhesive resin to the enamel surface.

Can all highly concentrated in-office bleaching gels be used as a single-application?

OBJECTIVE

This in vitro study aims to evaluate of hydrogen peroxide (HP) diffusion into the pulp chamber, bleaching efficacy (BE), and pH stability (pH) of single-application high concentrated in-office bleaching gels.

MATERIALS AND METHODS

Eighty-eight healthy premolars were randomly into eleven groups (n = 8) according to the in-office dental bleaching: DSP White Clinic 35% calcium (DW), Nano White 35% (NW), Opalescence XTra Boost 40% (OB), Pola Office + 37.5% (PO), Potenza Bianco Pro SS 38% (PB), Total Blanc 35% (TB), Total Blanc One-Step 35% (TO), Whiteness Automixx 35% (WA), Whiteness Automixx Plus 35% (WP), and Whiteness HP Blue 35% (WB). A group not exposed to bleaching agents was the control group (CG). All bleaching agents were applied in one session with a single application. After the bleaching procedure, the concentration of HP diffusion (μg/mL) into the pulp chamber was assessed using UV-Vis spectrophotometry. The BE (ΔEab and ΔE00) was evaluated before and 1 week after the bleaching procedure using a digital spectrophotometer. The pH of each bleaching gel was evaluated by digital pHmeter. The one-way ANOVA and Tukey's was used for a statistical analysis (α = 0.05).

RESULTS

The concentration of HP diffusion into the pulp chamber was higher in all in-office bleaching gels when compared to CG (p < 0.0000001). However, there are a significant difference between them (p = 0.0001). A significant BE was observed in all in-office bleaching gels (p < 0.0001 for ΔEab and ΔE00), with a significant difference between them (p < 0.0001). PO, OB, TB, WP, and WB showed a higher BE when compared to DW, PB, and WA (p < 0.0001). Most bleaching gels were slightly acidic or alkaline during the total application time, while DW, PB, TB, and WA showed a high acidic behavior after 30 min of application.

CONCLUSIONS

A single application was able to produce a bleaching efficacy. However, usually, gels with slightly acidic or alkaline pH during the application time reduces the HP diffusion into the pulp chamber.

CLINICAL RELEVANCE

The single-application of bleaching gels with slightly acidic or alkaline and stable pH decreased the penetration of hydrogen peroxide into the pulp chamber in in-office bleaching and maintained the bleaching efficacy.

Application Tip and Concentration of a Self-mixing Bleach: Hydrogen Peroxide Inside the Pulp Chamber, Color Change, and Amount of Bleaching Gel Used

PURPOSE

The objective of this study was to evaluate if the application method (tip with brush or tip without brush) and hydrogen peroxide (HP) concentration (6% or 35% self-mixing) of in-office bleaching gel influences the penetration of HP into the pulp chamber, color change, and the amount of bleaching gel used.

METHODS

Forty healthy premolars were randomly divided into the following five groups (n=8): no treatment; HP6% using a tip with a brush, HP6% using a tip without a brush, HP35% using a tip with a brush, and HP35% using a tip without a brush. After treatments, the HP concentration (μg/mL) within the pulp chamber was determined using UV-Vis spectrophotometry. The color change (ΔEab, ΔE00, and ΔWID) was evaluated using a digital spectrophotometer. The amount of gel used (g) in each group was measured using a precision analytical balance. Data from each test were submitted to parametric tests (α=0.05).

RESULTS

The tip with a brush resulted in a lower amount of HP inside the pulp chamber and less gel used when compared with the tip without a brush, regardless of HP concentration (p<0.05). However, regarding the tip used, although no significant difference was observed when HP35% was used (p>0.05), a higher whitening effect was observed when the 6% HP was applied without a brush as opposed to with a tip brush (p<0.05).

CONCLUSIONS

The use of a tip with a brush, regardless of the in-office bleaching gel concentration (6% or 35% self-mixing), presented a lower penetration and lower volume of spent gel when compared to a tip without brush. However, the whitening effect depended on the concentration of HP used.

A new approach for professional dental bleaching using a polymeric catalyst primer

OBJECTIVE

Evaluate the influence of a polymeric catalyst primer (PCP) on esthetic efficacy (EE), degradation kinetics of hydrogen peroxide (H₂ O₂ ), and trans-amelodentinal cytotoxicity (TC) of bleaching gels.

MATERIALS AND METHODS

The following groups were established: G1: No treatment (NC, negative control); G2: PCP; G3: 10% H₂ O₂ ; G4: PCP + 10% H₂ O₂ ; G5: 20% H₂ O₂ ; G6: PCP + 20% H₂ O₂ ; G7: 35% H₂ O₂ (positive control); G8: PCP + 35% H₂ O₂ . To determine EE, enamel/dentin discs (E/DDs) were stained and subjected or not to bleaching protocols for 45 min. To assess TC, the E/DDs were adapted to artificial pulp chambers. The extracts (culture medium + gel components diffused through E/DDs) were applied to odontoblast-like MDPC-23 cells. The viability (VB), oxidative stress (OxS), morphology (SEM), amount of H₂ O₂ diffused and the production of hydroxyl radical (OH^• ) were assessed (two-way ANOVA/Tukey/paired Student t-test; p < 0.05).

RESULTS

The highest EE was found in G8 (p < 0.05), and G4, G6, and G7 did not differ statistically (p > 0.05). In G4, the limited H₂ O₂ diffusion reduced OxS and increased cell VB (p < 0.05).

CONCLUSIONS

Coating the enamel with PCP containing 10 mg/ml of manganese oxide before applying the 10% H₂ O₂ bleaching gel maintains the EE of conventional in-office bleaching and minimizes the toxic effects of this esthetic therapy.

CLINICAL SIGNIFICANCE

Coating the enamel with a PCP before applying the bleaching gel may potentiate the EE of the conventional in-office tooth bleaching and reduce the toxicity of this professional therapy to the dental pulp.

Use of an applicator brush with high concentration bleaching gels

OBJECTIVES

To evaluate in vitro two high concentration self-mix bleaching gels (35% or 37.5%) with different application tips (with or without an applicator brush) during in-office bleaching.

MATERIALS AND METHODS

Healthy premolars were randomly assigned to five groups (n = 8): no treatment; 35% HP without applicator brush, 35% HP with applicator brush, 37.5% HP without applicator brush, and 37.5% HP with applicator brush. After the procedures, the concentration of HP transferred into the pulp chamber was evaluated using UV-Vis. The amount of gel used in each group was measured on a precision analytical balance. Color change (ΔEab, ΔE00, and ΔWID) was evaluated with a digital spectrophotometer. Initial concentration was measured by titration with potassium permanganate. The pH was evaluated using a digital pH meter. The data from each test were submitted to nonparametric tests (α = 0.05).

RESULTS

Using a tip with an applicator brush expended less gel and left a lower amount of HP inside the pulp chamber compared to the tip without a brush for both bleaching gels (p < 0.0003), although no significant difference in color change was observed (p < 0.05). The 37.5% HP showed a more stable and less acidic pH and a lower amount of HP in the pulp chamber than the 35% HP (p < 0.00001).

CONCLUSION

The HP penetration into the pulp chamber was lower when using an applicator with a brush tip than when using one with a conventional tip. As for the color, both tips were considered to lighten teeth.

CLINICAL SIGNIFICANCE

For the application of a self-mixing high concentration in-office bleaching gel, a brush tip should be recommended because its use diminishes the penetration of HP into the pulp chamber and wastes less bleaching gel.

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.

The effectiveness of in-office dental bleaching with and without sonic activation: A randomized, split-mouth, double-blind clinical trial

OBJECTIVE

This study was aimed at comparing the bleaching efficacy and bleaching sensitivity (BS) of two higher-concentration in-office bleaching gels (37% carbamide peroxide [CP] and 38% hydrogen peroxide [HP]) applied under two conditions: alone or in association with sonic activation.

METHODS

Fifty-six volunteers were randomly assigned in the split-mouth design into the following groups: CP, CP with sonic activation (CPS), HP, and HP with sonic activation (HPS). Two in-office bleaching sessions were performed. Color was evaluated using Vita Classical, Vita Bleachedguide, and digital spectrophotometer at baseline and at 30 days post-bleaching. Absolute risk and intensity of BS were recorded using two pain scales. All data were evaluated statistically (color changes [t test], BS [Chi-square and McNemar test], and BS intensity [VAS; t test; NRS; Wilcoxon; α = 0.05]).

RESULTS

Significant and higher whitening was observed for HP when compared with CP (p < 0.04). However, higher BS intensity was observed in the former (p < 0.001). No significant difference was observed in whitening effect or BS when the HP or CP bleaching gels were agitated (sonic application) compared with when they were not (p > 0.05).

CONCLUSION

The 37% CP gel demonstrated lower bleaching efficacy and lower BS compared with the 38% HP bleaching gel. The whitening effect was not influenced by the use of sonic activation.

CLINICAL SIGNIFICANCE

The use of 37% CP gel did not achieve the same whitening effect when compared to 38% HP gel used for in-office bleaching. The use of sonic activation offers no benefit for in-office bleaching.

The influence of the renewal or the single application of the peroxide gel on the efficacy and tooth sensitivity outcomes of in-office bleaching-A systematic review and meta-analysis

OBJECTIVE

To answer the question: "Does the peroxide gel application regimen (single application vs. renewal) influence the efficacy and the tooth sensitivity outcomes of in-office tooth bleaching?"

METHODS

The search was done in Pubmed, Cochrane, LILACS, Scopus, Web of Science, and EMBASE in February 2021 (updated in July 2021). Randomized clinical trials (RCT) comparing the single application vs. the renewal protocols of HP were included. The meta-analyses were performed for the objective (ΔE_ab ), subjective (ΔSGU) color changes, and absolute risk of tooth sensitivity (TS). Heterogeneity was evaluated using Q test (I² ). Cochrane Collaboration tool assessed the risk of bias (RoB). The GRADE evaluated the certainty of evidence.

RESULTS

Five RCT studies remained. Two studies showed high RoB, and three presented some concerns. No significant differences were observed between the protocols in terms of the ΔE_ab , ΔSGU, and TS. ΔE_ab exhibited substantial heterogeneity (I²  = 87%), while ΔSGU (I²  = 60%) and the TS (I²  = 62%) presented a moderate one. The certainty of evidence was considered low or very low, depending on the variable response and the evaluation time.

CONCLUSION

The application regimen (single vs. renewal of HP) did not impact color change or the absolute risk of TS.

CLINICAL SIGNIFICANCE

The renewal of bleaching gel during the in-office appointment may not be necessary. However, there is at least a low certainty of evidence. Because of this, further randomized clinical trials with appropriate methodology on this topic are encouraged.

Effects of whitening gels on color and surface properties of a microhybrid and nanohybrid composite

The aim of this study was to compare color changes, surface roughness and gloss of a microhybrid and nanohybrid composite whitened in a simulated in-office or at-home procedure using 40% hydrogen peroxide or 16% carbamide peroxide, respectively. CIELab coordinates were measured before, during and after treatment using VITA EasyShade V (VITA) and ∆E₀₀ calculated. Surface roughness was measured using a surface roughness tester (SJ210; Mitutoyo). Gloss was measured using a gloss checker (IG-331; Horiba). At-home whitening resulted in ∆E₀₀ of 1.23±0.49 (microhybrid) and 1.01±0.76 (nanohybrid). In-office exposure resulted in ∆E₀₀ of 0.69±0.38 (microhybrid) and 0.72±0.50 (nanohybrid). There were no significant differences in ∆E₀₀, surface roughness and gloss between whitening protocols (p>0.05). Color changes of a microhybrid and nanohybrid composite following simulated in-office or at-home whitening reached CIEDE2000 50:50% perceptibility but not acceptability threshold. Surface roughness and gloss of the microhybrid and nanohybrid composite were not affected by whitening.

Effects of a reduced in-office bleaching protocol with 37.5% hydrogen peroxide on effectiveness and tooth sensitivity: A double-blind randomized clinical trial

OBJECTIVE

This randomized clinical trial evaluated the effectiveness and tooth sensitivity (TS) of 37.5% hydrogen peroxide (37.5HP) in-office bleaching with reduced protocol.

MATERIALS AND METHODS

Forty participants with shade mean C2 or darker for the six maxillary anterior teeth were randomly allocated into two treatment groups (n = 20): two (37.5HP2) or three (37.5HP3) 8 min applications/clinical session. Three clinical sessions were performed with a 1 week interval. Color evaluations were done with a spectrophotometer at baseline and 1 week post-bleaching. TS was measured during and up to 48 h after bleaching using a five-point numeric rating scale. Color change was evaluated by Student's t-test for independent samples. The absolute risk and intensity of TS were analyzed by Fisher's and Mann-Whitney/Friedman tests (p < 0.05).

RESULT

Both treatment groups resulted in a significant tooth whitening 1 week post-bleaching (p < 0.001). There were no significant differences between 37.5HP2 and 37.5HP3 for ΔE*_ab , ΔE₀₀ and ∆WI_D . Also, there were not differences between groups regarding high absolute risk (p = 1.0) and low intensity of TS at all time assessments (p > 0.7).

CONCLUSIONS

The in-office bleaching with two 37.5% HP applications produced the same whitening degree, risk and intensity of TS to that performed with three gel applications.

CLINICAL SIGNIFICANCE

Clinicians should opt to use a neutral 37.5% HP in-office bleaching gel for two 8 min applications/clinical session because produces the same whitening effectiveness, risk and low intensity of TS as the protocol proposed by manufacturer (three 8 min applications).

Clinical evaluation of in-office tooth whitening with violet LED (405 nm): A double-blind randomized controlled clinical trial

BACKGROUND

Although there is little evidence showing the effectiveness of violet LED on in-office tooth whitening, there are some studies which have reported satisfactory results. This double-blind randomized controlled clinical trial aimed to evaluate the effect of a violet light emission diode (LED) (405 nm) system, used in-office, on tooth whitening, sensitivity, use of medication after whitening and quality of life.

METHODS

Eight patients were randomized into 4 groups (n = 20): G1 - violet LED, G2 - 35% carbamide peroxide (CP) and violet LED, G3 only CP 35% and G4 35% hydrogen peroxide (HP). The color was measured using a spectrophotometer at the following times: baseline, 15 and 180days. The colorimetric changes were analyzed using measurements from the CieLab System ΔE (ΔL, Δa and Δb) and the WID (Whiteness Index for Dentistry) for the 4 groups. Tooth sensitivity was recorded via a visual analog scale (VAS). Additionally, the Psychosocial Impact of Dental. Aesthetics Questionnaire (PIDAQ) was used to evaluate quality of life.

RESULTS

For the analysis of ΔL, G4 and G2 presented more brightness than G1 and G3 (p<0.05), implying that G2 is at least as good as G4 (p>0.05). For measure of Δa, G4 presented better results, standing out from the other groups. (p<0.05). For Δb, both G4 and G2 showed a greater tendency for blue color than groups G1 and G3 (p <0.05). When analyzing ∆E at the 180-day follow up, G4 produced the highest ∆E, while G3 showed the lowest ∆E. The other 2 whitening groups produced intermediate ∆E values. For ∆W, G1 and G3 significantly differed from G2 and G3. When analyzing the 180-day follow up, G2 produced the highest ∆W, while G3 showed the lowest ∆W. The other two whitening treatments produced intermediate ∆W values. As for sensitivity, only G4 patients showed dental sensitivity within 24 h of the bleaching, with pain ceasing after 48 h. For G4, 33% of the patients needed to take analgesics within the first 24 h after the first 3 whitening sessions. For PIDAQ, there was no overall decrease in score over time for any of the groups and there was no difference between them (p>0.05).

CONCLUSION

Our results showed that violet LED was not able to whiten teeth at the same intensity, when used alone, as it was when associated with 35% CP, contrary to our initial hypothesis. However, given that pain was not consistently reported in G2, one could suggest that treatment with LED + 35% CP is quite similar to that of 35% HP when used for tooth whitening, but with better pain outcomes. All treatments suggested an improvement in quality of life.Clinical Trial Registry: This trial is registered at ClinicalTrials.gov; the registration number is NCT03192852 https://clinicaltrials.gov/ct2/show/NCT03192852.

Titanium dioxide nanotubes incorporated into bleaching agents: physicochemical characterization and enamel color change

Titanium dioxide nanotubes are nanostructures that can accelerate the oxidation reaction of bleaching procedures and promote a more effective whitening effect.

Effects of Exposure to Cola-Based Soft Drink on Bleaching Effectiveness and Tooth Sensitivity of In-Office Bleaching: A Blind Clinical Trial

OBJECTIVE

The purpose of this single-blind (evaluators) and parallel design study was to evaluate whether exposure to a cola-based soft drink during bleaching treatment with 35% hydrogen peroxide (HP) affects color change and bleaching-induced tooth sensitivity.

MATERIAL AND METHODS

Forty-four patients with central incisors darker than A2 were selected. Participants who did not drink cola-based soft drinks were assigned to the control group (CG), while participants who drank a cola-based soft drink at least twice a day were assigned to the experimental group (EG). For the CG, foods with staining dyes were restricted. For the EG, there was no restriction on food and patients were asked to rinse their mouths with a cola-based soft drink for 30 s, 4 times daily. For both groups, 2 sessions with three 15 min applications of 35% HP were performed. Shade evaluation was assessed via subjective (VITA classical and VITA bleacheguide shade guides) and objective methods (Easyshade spectrophotometer) at baseline, during bleaching (first, second, and third weeks), and post bleaching (1 week and 1 month). Patients recorded their sensitivity perceptions using a numerical rating scale and 0-10 visual analog scales. Variation in shade guide units and the 2 colors (DE) were evaluated with a Student's t-test (α = 0.05) and Mann-Whitney test (α = 0.05). Absolute risk of tooth sensitivity and intensity of tooth sensitivity were evaluated by a Chi-square test (α=0.05).

RESULTS

Effective bleaching was observed for both groups after 30 days, without statistical difference (p > 0.08). There was no significant difference in absolute risk of bleaching-induced tooth sensitivity between the 2 groups (p = 0.74). Higher and significant scores in pain scales were detected for the EG in comparison to the CG (p < 0.05).

CONCLUSION

Even that the cola-based soft drink exposure during in-office bleaching treatments did not affect the bleaching's effectiveness; patients reported a higher intensity in bleaching-induced tooth sensitivity.

Effects of pH and Application Technique of In-office Bleaching Gels on Hydrogen Peroxide Penetration into the Pulp Chamber

Objective:

This in vitro study aimed to quantify the penetration of hydrogen peroxide (HP) into the pulp chamber in teeth submitted to in-office bleaching with varied pH and application techniques. The color change and pH of the in-office bleaching product during application was also evaluated.

Methods and Materials:

Ninety-six human premolars were used and randomly divided into 10 groups (n=9) according to the following combination of factors: pH of in-office bleaching agents (two neutral/alkaline pH: Opalescence Boost 38% and Whiteness HP Blue 35% and three acidic pH: Whiteness HP Maxx 35%, Lase Peroxide Sensy 35%, and Total Blanc Office 35%) and application modes (for 3 × 15 minutes [3×15] and 1 × 45 minutes [1×45]). An additional group of non-bleached teeth (control; n=6) was added. First, all teeth were sectioned 3 mm from the cementoenamel junction and the pulp tissue was removed. An acetate buffer was placed in the pulp chamber of all teeth. After bleaching, this solution was transferred to a glass tube in which HP was allowed to react with other components, resulting in a pink solution. The optical density of this pink solution was measured using ultraviolet-visible spectroscopy and converted into amount of HP. Color change before and 1 week after bleaching was evaluated using a digital spectrophotometer. A pH meter with a 6-mm circular and flat surface was used in contact with the enamel surface to quantify the pH of the bleaching gels during application. Data were analyzed using two-way analysis of variance and Tukey tests (α=0.05).

Results:

Overall, lower mean HP penetration values were observed for Opalescence Boost 38% and Whiteness HP Blue 35% compared with other bleaching gels (p&lt;0.05). Opalescence Boost 38% and Whiteness HP Blue 35% were not influenced by the application technique (p&gt;0.05). However, lower mean HP penetration values were observed for Whiteness HP Maxx 35%, Total Blanc Office 35%, and Lase Peroxide Sensy 35% when using the 3×15 application technique compared with the 1×45 technique (p&lt;0.05). Significant whitening was detected and no significant difference of color change was observed between groups (p&gt;0.54). The pH did not change during the 3×15 application technique; however, all acidic bleaching gels significantly decreased in pH when applied for 1×45 (p&lt;0.01).

Conclusions:

The amount of HP that reaches the pulp chamber was lower when neutral/alkaline pH gels were used, independently of the application technique. When considering acidic pH gels, it is preferable to use the 3×15 application technique, mainly because longer application time (1×45) results in lower pH. No difference was observed between groups with regards to color change.

Clinical Evaluation of In-Office Dental Bleaching Using a Violet Light-Emitted Diode

Objective: To clinically evaluate the effect of the violet light-emitted diode (LED) light (405-410 nm) associated to in-office dental bleaching with 35% carbamide peroxide, on tooth color change and sensitivity. Participant's satisfaction after treatment was also evaluated. Materials and methods: A total of 50 participants were selected and randomized into a treatment group (n = 25): G1-two bleaching sessions of 30 min each, with 7-day interval (D0 and D7); G2-two bleaching sessions (same protocol as G1) associated with violet LED light, 30 min each session. The color evaluation was performed before and after 7 days of the second session (D0 and D14); the medium third of buccal surface of canine and central incisor teeth were evaluated under VITA Shade Guide and spectrophotometry (subjective and objective). Tooth sensitivity was evaluated immediately after the treatment and after 48 h of each bleaching session (D0, D2, D7, and D9), and a self-perception questionnaire was applied on D14. Results: Data were subjected to nonparametric Mann-Whitney test and both canine and central incisor teeth presented color change. Group G2 showed significantly more change than G1. Fisher's exact test showed no statistically significant dental sensitivity differences between groups. Both groups reported a high level of satisfaction but chi-square test showed statistically higher satisfied patients with dental bleaching in G2 than G1. Conclusions: The violet LED light (405-410 nm) could improve dental bleaching effectiveness, without sensitivity increase.

Hydrogen peroxide-based products alter inflammatory and tissue damage-related proteins in the gingival crevicular fluid of healthy volunteers: a randomized trial

Hydrogen peroxide (H2O2)-based products are effective in tooth whitening; however, their safety is controversial as they may harm patient tissues/cells. These effects are suggested to be concentration-dependent; nonetheless, to date, there are no reports on H2O2-mediated oxidative damage in the gingival tissue, and neither whether this can be detected in gingival crevicular fluid (GCF) samples. We hypothesize that H2O2 whitening products may cause collateral oxidative tissue damage following in office application. Therefore, H2O2 and nitric oxide (NO) levels were investigated in GCF samples obtained from patients undergoing dental bleaching with H2O2 at different concentrations, in a randomized, double-blind, split-mouth clinical trial. A proteomic analysis of these samples was also performed. H2O2-based whitening products promoted inflammation which was detected in GCF samples and lasted for longer following 35% H2O2 bleaching. This included time-dependent changes in NO levels and in the abundance of proteins associated with NO synthesis, oxidative stress, neutrophil regulation, nucleic acid damage, cell survival and/or tissue regeneration. Overall, H2O2-based products used in office promote inflammation irrespective of their concentration. As the inflammation caused by 35% H2O2 is longer, patients may benefit better from using lower concentrations of this bleaching product, as they may result in less tissue damage.