High-concentration carbamide peroxide can reduce the sensitivity caused by in-office tooth bleaching: a single-blinded randomized controlled trial

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 hours 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.

Effectiveness and one-year whiteness stability of different in-office bleaching agents and alternative protocols

STATEMENT OF PROBLEM

In-office bleaching has been widely researched. However, few studies have evaluated alternative protocols for this procedure. Moreover, information on the long-term stability of in-office whitening is limited.

PURPOSE

The purpose of this in vitro study was to evaluate the effectiveness and 1-year stability of in-office bleaching with 35% hydrogen peroxide (35%HP) and 37% carbamide peroxide (37%CP) using traditional and alternative protocols.

MATERIAL AND METHODS

Forty human third molars were stained with tea and allocated to groups (n=10). Traditional protocols consisted of 3 applications of 35%HP for 15 minutes and 1 application of 37%CP for 45 minutes. Alternative protocols consisted of 1 application of 35%HP for 45 minutes and 3 applications of 37%CP for 45 minutes. Protocols were applied for 3 weeks. CIELab color coordinates were measured at baseline and weekly during treatment and at 1-week, 6-month, and 1-year follow-ups. Effectiveness and stability of the bleaching treatments were interpreted using 50:50% perceptibility and acceptability thresholds. CIELab, chroma, hue angle, and whiteness index were analyzed using the Wilcoxon signed-rank test (α=.05).

RESULTS

All protocols showed improvement in bleaching after the first week (P≤.005). All bleaching procedures presented excellent whitening outcomes. Alternative protocols showed a larger rebound effect after 1 year, indicating less stability. For the whiteness index, no differences between the completion of the treatments and 1-year follow-up was found for the bleaching treatments and protocols (P>.05), except for the 37%CP alternative protocol (P=.005).

CONCLUSIONS

All tested protocols presented excellent effectiveness in bleaching. Traditional protocols exhibited a greater whiteness stability, while the alternative protocols showed a greater rebound effect after 1 year.

Trends and Gaps in Clinical Research on Tooth Bleaching: A Bibliometric Analysis of Studies Published From 2001 to 2024

INTRODUCTION

The objective of this bibliometric review is to address the main trends and development in dental whitening throughout the 21st century, as well as to identify knowledge gaps on the subject.

METHOD

A search was conducted in the Web of Science Core Collection database and information was extracted regarding the journal, authors, keywords, year of publication, number of citations, country, continent of the corresponding author. After reading the articles, data such as study design, type of bleaching technique, types of light sources used with the bleaching, occurrence of tooth sensitivity, and tooth color change analysis method were extracted.

RESULTS

The journal with the largest number of publications was "Operative dentistry" (n = 61), and the authors with the most articles were Loguercio AD (n = 82) and Reis A (n = 76). The productions are concentrated in Brazil, with emphasis on the State University Ponta Grossa. Most of the articles are randomized clinical studies that used the in-office bleaching technique with 35% hydrogen peroxide.

CONCLUSION

Our results show that the most recent studies used light sources such as a violet LED during whitening; however, more studies are needed to prove the benefits in relation to color change and reduction of tooth sensitivity.

In-Office Dental Bleaching Using 37% Carbamide Peroxide Versus 35% Hydrogen Peroxide: A Randomized, Double-Blind Clinical Trial

OBJECTIVE

Compare the tooth sensitivity (TS) and bleaching efficacy (BE) of in-office dental bleaching performed with 35% hydrogen peroxide (HP) or 37% carbamide peroxide (CP).

MATERIALS AND METHODS

Sixty-six participants were randomly divided into two groups according to the bleaching gel applied to the right hemiarch: 35% HP, or 37% CP. TS was recorded immediately after, up to 1, 24, and 48 h after bleaching, using the VAS and NRS scales. BE was assessed before bleaching and 1 month after using color guide units (ΔSGUs) and a spectrophotometer (ΔEab, ΔE00, and ΔWID). TS was assessed using McNemar's and paired t-test (VAS) or Wilcoxon signed rank (NRS). The paired t-test was used to analyze BE (α = 0.05).

RESULTS

TS risk and intensity were lower for the 37% CP (p = 0.003 and p < 0.005). Despite significant differences between the groups after 1 month (ΔSGU and ΔE00; p < 0.05), the color measurements of both groups exceeded the 50%:50% perceptibility/acceptability threshold.

CONCLUSION

In-office dental bleaching using 37% CP resulted in reduced risk and TS intensity, without prejudice to the BE.

CLINICAL RELEVANCE

The use of 37% CP for in-office dental bleaching could decrease TS risk and intensity without affecting BE.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: RBR-683qhf.

Assessment of changes in optical and mechanical properties and adverse effects of over-the-counter bleaching agents: An in vitro study

Background

This in vitro study evaluated the impact of over-the-counter (OTC) products on the optical properties (color and gloss changes) and mechanical properties (shear bond strength) of tooth enamel subjected to a simulated orthodontic treatment.

Material and Methods

80 bovine teeth were selected and subjected to a staining protocol and initial color assessments. Then, orthodontic brackets were bonded on the center of the clinical crown of each sample, and teeth underwent the bleaching protocols. The samples were allocated to five groups (n=16): Conventional in-office bleaching 35% Hydrogen peroxide - positive control (HP35); Dentifrice with 2% HP (DHP); Mouthwash with 2.5% HP (MouHP); Paint-on with 6% HP (PON); Conventional dentifrice without HP - negative control (DWHP). After receiving the bleaching protocol, the samples underwent the shear bond strength test for orthodontic bracket removal. The remaining resin was then removed from the sample surfaces using multi-blade burs. Data was analyzed with Kruskal-Wallis test or one-way ANOVA, with 5% significance.

Results

Regarding color change, multiple comparison analyses showed significant differences (p< 0.05). The HP35 and MouHP groups showed a significantly greater color change compared to the DWHP and DHP groups for both ΔE00 and ΔEab values, while the PON group did not differ significantly from the other groups. The statistical test did not detect a significant difference in post-bleaching gloss increase between the experimental groups (p=0.20). In addition, it did not detect a significant difference between the experimental groups for shear assessment (p=0.14).

Conclusions

Except for dentifrices, the color change outcomes of the evaluated OTC bleaching treatments were as satisfactory as in-office bleaching, without differences between groups for gloss change. The study suggests that the evaluated OTC products did not influence the bond strength of orthodontic brackets to teeth. Key words:Hydrogen Peroxide, In Vitro Technique, Tooth Bleaching, Tooth Bleaching Agents.

Impact of nanostructured additives in tooth bleaching agents on enhancing color change and reducing side effects: a scoping review

OBJECTIVES

This study aimed to determine whether incorporating nanostructured additives into bleaching agents enhances efficacy and reduces side effects while identifying gaps for further investigation.

METHODS

A comprehensive search was conducted in electronic databases, including PubMed/Medline, Embase, Scopus, and ISI Web of Science. Two reviewers independently screened articles based on predefined criteria, resolving discrepancies through discussion or consultation with a third reviewer. Data extraction focused on key details, including study design, interventions, and outcomes.

RESULTS

Twenty-one articles were reviewed, consisting of nine clinical studies, one in vivo/in situ study, and 11 in vitro studies on tooth bleaching protocols. Hydrogen peroxide was the most commonly used bleaching agent. The primary nanostructured additives studied were titanium dioxide nanoparticles, polymeric carbamide peroxide nanoparticles, chitosan nanoparticles, nano-hydroxyapatite, SiO2/MgO/Fe2O3 nanocomposite spheres, and nano-bioactive glass. Most studies demonstrated an enhanced bleaching effect, reduced bleaching sensitivity, decreased cytotoxicity, reduced hydrogen peroxide penetration into the pulp chamber, and protection of the tooth surface against mineral and structural loss when nanostructured additives were incorporated into the bleaching agent.

CONCLUSIONS

Incorporating nanostructured additives into tooth-bleaching agents improved efficacy and reduced side effects, especially with titanium oxide nanoparticles. Further clinical studies and systematic reviews are needed to establish strong evidence for safe clinical practice.

CLINICAL RELEVANCE

Including nanostructured additives in bleaching agents, such as titanium oxide nanoparticles, might be a valuable approach to enhancing the bleaching potential while reducing bleaching sensitivity and cytotoxicity, offering safer alternatives for clinical protocols.

Effectiveness of violet LED with or without a bleaching gel: a 12-month randomized clinical trial

Introduction

The present interventional, controlled, randomized, blind clinical study aimed to evaluate the effectiveness of an in-office bleaching procedure with violet LED associated or not with 37% carbamide peroxide, considering as response variables the degree of change and color stability over 12 months and dental sensitivity over a month.

Methods

Forty participants, according to the inclusion and exclusion criteria, were randomly divided into 2 groups (n = 20) according to the bleaching protocol conducted, in two sessions, with a 7-day interval: vLED-violet LED, without gel; vLED/CP-37% carbamide peroxide photocatalyzed with violet LED (control group). In the vLED group, in each session the bleaching was carried out by 2 consecutive irradiation cycles of 25' each (10 × 2' LED + 30" interval), with 5' interval between cycles. In the vLED/CP group, the gel was applied 5 times in the bleaching session and photocatalyzed 3 times for 2' with 30" intervals (7'30" per gel application), totaling 37'30" per session. Dental sensitivity was assessed using a visual analog scale (VAS) and the effectiveness of bleaching as a function of the degree of change and color stability (ΔE) with a spectrophotometer. The data were tabulated and submitted to statistical tests (p < 0.05).

Results

The VAS analysis showed that some individuals from both groups had mild pain (1 ≤ VAS < 4) during the time intervals evaluated, being more prevalent in the vLED/CP group. Regarding the degree of color change, the groups behaved differently over time (p < 0.0001). The ΔE observed for the vLED/CP group was superior in comparison to the vLED group at all evaluated moments.

Conclusions

Over 12 months, the vLED/CP group was more effective in relation to the bleaching effect compared to the vLED group. Both groups showed low levels of sensitivity in the studied time intervals.

Clinical Trial Registration

[https://ensaiosclinicos.gov.br/rg/RBR-6rc23h], identifier [U1111-1253-8850].

Can carbamide peroxide be as effective as hydrogen peroxide for in-office tooth bleaching and cause less sensitivity? A systematic review

This study aimed to answer the question through a systematic review: Can carbamide peroxide be as effective as hydrogen peroxide and cause less in-office bleaching sensitivity? A literature survey was performed in PubMed/MEDLINE, Embase, Scopus, ISI Web of Science, and gray literature. Primary clinical trials that compared the efficacy or the in-office bleaching sensitivity between carbamide and hydrogen peroxides were included. The risk of bias was evaluated using the RoB2. The certainty of the evidence was assessed using the GRADE approach. DPI training significantly improved the mean scores of the dental undergraduates from 7.53 in the pre-DPI-training test to 9.01 in the post-DPI-training test (p < 0.001). After 6 weeks, the mean scores decreased marginally to 8.87 in the retention test (p = 0.563). DPI training increased their confidence level from 5.68 pre-DPI training to 7.09 post-DPI training. The limited evidence suggests that the 37% carbamide peroxide may be similarly effective to the 35% hydrogen peroxide for bleaching teeth in-office and causes less bleaching sensitivity. However, more well-designed split-mouth clinical trials are necessary to strengthen the evidence.

Influence of repositioning guides' color and usage on precision in tooth color measurement with a clinical spectrophotometer

BACKGROUND

Repositioning guides are commonly employed in clinical studies to ensure consistent tooth color measurements. Yet, their influence on measured color remains uncertain.

OBJECTIVE

This study evaluated the impact of repositioning guides' color and usage on tooth color measurement using a clinical spectrophotometer.

METHODOLOGY

In total, 18 volunteers participated in this study, in which the color of their upper left central incisor and upper left canine was measured with or without repositioning guides (control). The guides were made from pink, blue, or translucent silicone, as well as an acetate-based bleaching tray. Tooth color was measured in triplicates using a clinical spectrophotometer based on the CIELAB system. The standard deviations of these readings were used to estimate reproducibility, and color differences (ΔE00) between the measurements with guides and the control were calculated.

RESULTS

Repositioning guides had a minimal effect on L* values and no effect on b* values. The use of pink silicone increased a* values, whereas blue or translucent silicone reduced them. Irrespective of the evaluated tooth, the lowest ΔE00 values were observed for the translucent silicone and bleaching tray. The usage of guides only affected data variability for the L* color coordinate.

CONCLUSION

Using repositioning guides can significantly impact the precision of tooth color measurement with a clinical spectrophotometer.

Assessment of color changes and adverse effects of over-the-counter bleaching protocols: a systematic review and network meta-analysis

OBJECTIVES

To assess color change efficacy and the adverse effects of varied over-the-counter (OTC) bleaching protocols.

METHODOLOGY

The study included randomized clinical trials evaluating color changes from OTC bleaching agents. Nine databases were searched, including the partial capture of the grey literature. The RoB2 tool analyzed the individual risk of bias in the studies. Frequentist network meta-analyses compared treatments through common comparators (∆Eab* and ∆SGU color changes, and tooth sensitivity), integrating direct and indirect estimates and using the mean and risk differences as effect measures with respective 95% confidence intervals. The GRADE approach assessed the certainty of the evidence.

RESULTS

Overall, 37 remaining studies constituted the qualitative analysis, and ten composed the meta-analyses. The total sample included 1,932 individuals. ∆Eab* was significantly higher in groups 6% hydrogen peroxide (HP) strips (≥ 14 h). ∆SGU was significantly higher in groups at-home 10% carbamide peroxide (CP) (≥ 14 h), followed by 6% HP strips (≥ 14 h) and 3% HP strips (≥ 14 h). At-home 10% CP (7-13 h) and placebo showed lower risks of tooth sensitivity without significant differences between these treatments.

CONCLUSION

Considering the low level of evidence, OTC products presented satisfactory short-term effects on tooth bleaching compared to the placebo, with little to no impact on dentin hypersensitivity and gingival irritation.

CLINICAL RELEVANCE

OTC products are proving to be practical alternatives for tooth whitening. However, patients should be advised about the possible risks of carrying out such procedures without professional supervision.

Effect of gingival barrier brands on operator perception, cervical adaptation, and patient comfort during in-office tooth bleaching: a randomized clinical trial

BACKGROUND

Light-cured resins are widely used as gingival barriers to protect the gums from highly concentrated peroxides used in tooth bleaching. The impact of barrier brand on clinical outcomes is typically considered negligible. However, there is limited evidence on the effects of different brands on operator experience, barrier adaptation, and patient comfort.

OBJECTIVE

This clinical trial assessed the impact of four commercial gingival barrier brands (Opaldam, Topdam, Lysadam, and Maxdam) on operator perception, adaptation quality, and patient comfort.

METHODS

Twenty-one undergraduate students placed gingival barriers in a randomized sequence using blinded syringes. Photographs of the barriers were taken from frontal and incisal perspectives. After bleaching procedures, operators rated handling features and safety using Likert scale forms. Two experienced evaluators independently assessed barrier adaptation quality on a scale from 1 (perfect) to 5 (unacceptable). The absolute risk of barrier-induced discomfort was recorded. Data were analyzed using Friedman and Chi-square tests (α = 0.05).

RESULTS

Opaldam and Topdam received the highest scores in most handling features, except for removal, which was similar among all brands. No significant difference was observed in barrier adaptation quality between the evaluated brands. Discomforts were mainly reported in the upper dental arch, with Maxdam having the highest absolute risk (35% for this arch and 24% overall).

CONCLUSIONS

This study suggests that gingival barrier brands can influence operator perception and patient comfort. Opaldam and Topdam were preferred by operators, but all brands demonstrated comparable adaptation quality.

CLINICAL TRIAL REGISTRATION

The study was nested in a randomized clinical trial registered in the Brazilian Clinical Trials Registry under identification number RBR-9gtr9sc.

Treatment Durations and Whitening Outcomes of Different Tooth Whitening Systems

Background and Objectives: Tooth whitening is a relatively conservative and effective option to treat discolored teeth. However, questions remain whether in-office or at-home tooth whitening products with short treatment durations are as effective and stable as products with longer treatment durations. Materials and Methods: Forty human third molars with intact enamel surfaces were divided into four groups of ten each, subjected to discoloration challenges with coffee for 60 h, and they were treated with four professional tooth whitening systems: two for take-home use-6% hydrogen peroxide for 30 min/d for a total of 7 h in 14 days (HP6), 10% carbamide peroxide for 10 h/d for 140 h in 14 days (CP10), as well as two for in-office use-35% HP for 10 min × 3 (HP35) for a total of 30 min and 40% HP for 20 min × 3 (HP40) for a total of 60 min. Teeth colors were assessed in the CIE L*a*b* color space with a spectrophotometer immediately and six months after whitening treatments. Surface roughness (Sa) for the treated and untreated enamel surfaces of the teeth in all groups were evaluated with a three-dimensional laser scanning microscope after six months. Results: No significant differences were found between HP6 and CP10 groups immediately after whitening (∆E 10.6 ± 1.6 vs. 11.4 ± 1.7, p > 0.05) and at six months after treatments (∆E 9.0 ± 1.9 vs. 9.2 ± 2.5, p > 0.05), or between HP35 and HP40 groups immediately after whitening (∆E 5.9 ± 1.2 vs. 5.3 ± 1.7, p > 0.05) and at six months after treatments (∆E 7.2 ± 1.6 vs. 7.7 ± 1.3, p > 0.05). The two at-home whitening systems achieved significantly better whitening outcomes than the two in-office products immediately after whitening (p < 0.05). However, at six months after treatments, the differences between at-home and in-office treatments had narrowed significantly (p > 0.05). There were no statistically significant differences with respect to the Sa values between the treated and untreated surfaces (p > 0.05). Conclusions: Tooth whitening products in the same product category have similar whitening efficacies, despite significant differences in treatment durations (7 vs. 140 h, and 30 min vs. 60 min, respectively). Take-home products achieved better whitening outcomes than in-office products, but they needed 14 to 280 times longer treatment durations.

Determination of Microhardness of Remineralized Bleached Surface Subjected to Erosion-An In Vitro Study

Objectives

The aim of this study is to evaluate the microhardness of remineralized bleached surface subjected to erosion.

Materials and methods

Fifteen samples were divided into three groups and subjected to bleaching and erosion treatment. Group I-treated with 30% hydrogen peroxide then treated with 1% citric acid solution; group II-treated with 30% hydrogen peroxide and a remineralizing agent followed by 1% citric acid solution; group III-without bleaching with 1% citric acid solution. Five samples per group, GI, GII, and GIII were subjected to the Vickers microhardness analysis. Loss of surface hardness loss (% SHL) was analyzed followed by one-way ANOVA test, post hoc multiple comparison test, Bonferroni test to compare the various group.

Result

Group II showed the lowest % SHL after the erosive phase when compared with group I.

Conclusion

Erosion which usually occurs as a consequence of bleaching can be minimized by the application of remineralizing agents after bleaching.

How to cite this article

Chandrashekhar S, Mithare SS, Bharath M, et al. Determination of Microhardness of Remineralized Bleached Surface Subjected to Erosion-An In Vitro Study. Int J Clin Pediatr Dent 2023;16(1):97-100.

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.

Structure and hydration of polyvinylpyrrolidone-hydrogen peroxide

The structure of the commercially important polyvinylpyrrolidone-hydrogen peroxide complex can be understood by reference to the co-crystal structure of a hydrogen peroxide complex and its mixed hydrates of a two-monomer unit model compound, bisVP·2H₂O₂. The mixed hydrates involve selective water substitution into one of the two independent hydrogen peroxide binding sites.

Colorimetric evaluation after in-office tooth bleaching with violet LED: 6- and 12-month follow-ups of a randomized clinical trial

OBJECTIVES

To evaluate the long-term outcomes of in-office bleaching with violet LED light (LED) alone or combined with carbamide (CP) or hydrogen (HP) peroxides.

METHODS

Volunteers of a previous short-term study were recalled for 6- and 12-month follow-ups, according to the following interventions (n = 18/group): LED, CP, LED/CP, HP, and LED/HP. The objective color (ΔE_ab, ΔE₀₀) and whiteness index (ΔWI_D) changes were calculated applying the CIELab coordinates' values obtained using a spectrophotometer. A visual shade guide determined the tooth's subjective color change (ΔSGU). Data were submitted to one-way ANOVA or Welch's ANOVA, following appropriate post hoc tests (α = 5%).

RESULTS

The LED and CP groups exhibited the lowest ΔE_ab, ΔE₀₀, and ΔSGU (p < 0.05), but the LED group displayed a significantly lower ΔWI_D. After 12 months, the LED/CP group presented a higher ΔE_ab and ΔE₀₀ than the CP group (p < 0.05). ΔE_ab, ΔE₀₀, ΔSGU, or ΔWI_D means did not differ statistically between the LED/CP and HP groups. The LED/HP group presented a higher ΔE₀₀ than the HP group, regardless of the time.

CONCLUSIONS

The bleaching efficacy of LED alone was significantly lower compared to the LED/CP and HP-containing protocols. After 12 months, the LED/CP and HP groups did not differ in bleaching efficacy. LED irradiation only increased the objective color change of bleaching gels.

CLINICAL RELEVANCE

LED alone promoted a long-term perceptible bleaching, but not compatible with that of high-concentrated HP. The bleaching outcomes of violet irradiation to 37% CP were maintained over time, with LED/CP demonstrating comparable results to HP even after 12 months.

NATIONAL CLINICAL TRIALS REGISTRY (REBEC)

RBR-5t6bd9.

Comparison of the Effect of Agitation on Whitening and Tooth Sensitivity of In-Office Bleaching: A Randomized Clinical Trial

OBJECTIVE

This single-blind, split-mouth, randomized trial was aimed at evaluating the bleaching efficacy (BE) and tooth sensitivity (TS) of a 20% hydrogen peroxide (HP) bleaching agent used under active or passive application.

METHODS AND MATERIALS

Twenty-two patients with canines darker than C2 were selected. Teeth were bleached in two sessions, with a one-week interval between treatments. The bleaching agent was applied using active (HPactive) or passive (HPpassive) application. Each tooth in the HPactive-allocated hemiarch received bleaching gel with sonic activation after 10 and 30 minutes from the start of treatment, with rounded movements all over the buccal surface. The color changes were evaluated by subjective (Vita Classical and Vita Bleachedguide) and objective (VITA Easyshade Spectrophotometer) methods at baseline and 30 days after the second session. TS was recorded up to 48 hours after treatment using a 0-10 visual analog scale. Color change in shade guide units (SGUs) and ΔE was analyzed using a Wilcoxon test (α=0.05). The absolute risk and intensity of TS were evaluated using McNemar test and a Wilcoxon test, respectively (α=0.05).

RESULTS

Significant whitening was observed in both groups after 30 days of clinical evaluation. The activation did not significantly influence BE (ΔSGU HPpassive=5.6 and HPActive=5.8; p=0.98; and ΔE HPpassive=10.6 and HPactive=10.3; p=0.83). Absolute risk of TS (HPactive=36.4% and HPpassive=31.8%; p=0.94) was similar for both groups (Fisher exact test). TS intensity (visual analogue scale) was higher during the bleaching sessions and up to 24 hours thereafter for both groups, with no differences between groups (twoway analysis of variance and Tukey).

CONCLUSION

The active application of a 20% HP gel did not improve BE and TS.

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.

Effect of violet LED light on in-office bleaching protocols: a randomized controlled clinical trial

Objective

This study evaluated the clinical effect of violet LED light on in-office bleaching used alone or combined with 37% carbamide peroxide (CP) or 35% hydrogen peroxide (HP).

Methodology

A total of 100 patients were divided into five groups (n=20): LED, LED/CP, CP, LED/HP and HP. Colorimetric evaluation was performed using a spectrophotometer (ΔE, ΔL, Δa, Δb) and a visual shade guide (ΔSGU). Calcium (Ca)/phosphorous (P) ratio was quantified in the enamel microbiopsies. Measurements were performed at baseline (T ₀ ), after bleaching (T _B ) and in the 14-day follow-up (T ₁₄ ). At each bleaching session, a visual scale determined the absolute risk (AR) and intensity of tooth sensitivity (TS). Data were evaluated by one-way (ΔE, Δa, ΔL, Δb), two-way repeated measures ANOVA (Ca/P ratio), and Tukey post-hoc tests. ΔSGU and TS were evaluated by Kruskal-Wallis and Mann-Whitney, and AR by Chi-Squared tests (a=5%).

Results

LED produced the lowest ΔE (p<0.05), but LED/HP promoted greater ΔE, ΔSGU and Δb (T ₁₄ ) than HP (p<0.05). No differences were observed in ΔE and ΔSGU for LED/CP and HP groups (p>0.05). ΔL and Δa were not influenced by LED activation. After bleaching, LED/CP exhibited greater Δb than CP (p>0.05), but no differences were found between these groups at T ₁₄ (p>0.05). LED treatment promoted the lowest risk of TS (16%), while HP promoted the highest (94.4%) (p<0.05). No statistical differences of risk of TS were found for CP (44%), LED/CP (61%) and LED/HP (88%) groups (p>0.05). No differences were found in enamel Ca/P ratio among treatments, regardless of evaluation times.

Conclusions

Violet LED alone produced the lowest bleaching effect, but enhanced HP bleaching results. Patients treated with LED/CP reached the same efficacy of HP, with reduced risk and intensity of tooth sensitivity and none of the bleaching protocols adversely affected enamel mineral content.

Effect of bleaching with carbamide peroxide on shear bond strength of orthodontic brackets: A meta-analysis of in vitro studies

INTRODUCTION

This study aimed to evaluate the effect of bleaching with carbamide peroxide (CP) according to different doses and intervals between bleaching and bonding on shear bond strength (SBS) of orthodontic brackets.

METHODS

Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, PubMed, and Scopus were searched for articles published up to June 2018. After removing the duplicates, two of the authors screened the titles and abstracts independently. Assessing the eligibility of the selected full texts was also conducted by two of the authors independently. Disagreements were resolved by discussion. Modified version of Cochrane's risk of bias tool was used to assess the quality of studies. Fifteen studies were selected.

RESULTS

Overall, bleaching with CP decreased the SBS by around 2MPa (P<0.0001). Using 10% CP decreased the SBS of the immediately bonded brackets by 5.13MPa (P<0.005). This value was 1.67MPa when the bonding procedure was postponed by one day (P<0.0001). Postponing the bonding procedure for longer periods did not cause a statistically significant change in SBS. Using 11-16% CP, the reduction in SBS of the immediately bonded brackets was 8.51MPa (P<0.01). The SBS decreased by 4.12MPa when the bonding procedure was postponed for 20days (P<0.05). According to one study, use of CP with>16% concentration seemed not to affect the SBS.

CONCLUSIONS

Bleaching with CP decreases the SBS, especially if the bracket bonding is performed shortly after bleaching. However, given the small number of articles interpretation should be made with caution.

Evaluation of In-office Vital Tooth Whitening Combined with Different Concentrations of At-home Peroxides: A Randomized Double-blind Clinical Trial

Background:

The clinical evidence relate the effect of associating the in-office and at home vital tooth whitening, describing positive effects on tooth color change and reduction of dental sensitivity.

Objective:

The purpose of this randomized double-blind clinical trial was to evaluate the effect on the shortened application of in-office vital tooth whitening combined with different concentrations of at-home peroxides in the final tooth color change and dental sensitivity.

Methods:

Randomized double-blind clinical trial with 120 participants between 18-65 years, allocated in four tooth whitening treatment groups: G1= Carbamide Peroxide 10% + Hydrogen Peroxide 40%, G2= Carbamide Peroxide 15% + Hydrogen Peroxide 40%, G3= Carbamide Peroxide 20% + Hydrogen Peroxide 40%, G4= Hydrogen Peroxide 10% + Hydrogen Peroxide 40% was conducted. Tooth color was measured at baseline and dental sensitivity and tooth color change during and after treatment.

Results:

No statistical significant differences were found in tooth color change (superior arch p= 0.183 / inferior arch p= 0.374), and in dental sensitivity (p=0.268).

Conclusion:

Reducing the application time of in-office whitening, combined with in-home products was effective in improving the color. All groups resulted in identical final color change and dental sensitivity.

Clinicaltrials.gov: NCT02682329 Available from: https://clinicaltrials.gov/ct2/show/NCT02682329?term=hydrogen+peroxide.

Is a Single Preliminary Session of In-office Bleaching Beneficial for the Effectiveness of At-home Tooth Bleaching? A Randomized Controlled Clinical Trial

OBJECTIVES

To evaluate the effect of combining in-office with at-home bleaching procedures in terms of the time required to obtain satisfactory tooth color, final color changes, and tooth sensitivity (TS) reported by patients.

METHODS AND MATERIALS

Twenty-six patients enrolled in this study used 10% carbamide peroxide in a bleaching tray for 1 h/d until satisfactory tooth color was obtained. One-half of the participants underwent a preliminary session of in-office tooth bleaching with 35% hydrogen peroxide for 45 minutes. The time in days for the patients to obtain satisfactory tooth color by at-home bleaching procedures was recorded. The color change of the maxillary canines was assessed using the Vita Bleachedguide 3D Master scale and a spectrophotometer at 1 week and after the end of bleaching procedures. Participants' satisfaction with their smile was recorded using a visual analog scale, and TS was determined throughout the entire treatment. Data were analyzed by t-test, Mann-Whitney test, or Fisher exact test (α=0.05).

RESULTS

The combined protocol reduced (by an average of 3.7 days) the time required to obtain satisfactory tooth color but increased the risk and level of TS. No difference in the final tooth color change (around 5.0 shade guide units; ΔE=11.6-14.9), or the level of patients' satisfaction with their smile, was observed.

CONCLUSIONS

A preliminary session of in-office bleaching reduced the time necessary to obtain satisfactory tooth color with at-home bleaching but increased the risk and level of TS.