Comparison of Effectiveness of Two 10% Carbamide Peroxide Tooth-Bleaching Systems Using Spectrophotometric Measurements

Efficacy of Tooth Bleaching With Prior Application of Two Different Desensitizing Agents: An In Vitro Study

Objective To compare and evaluate the efficacy of tooth bleaching with prior application of two different desensitizing agents such as sodium fluoride and 5% potassium nitrate. Materials and methods A total of 108 extracted human maxillary central incisors were stained in black coffee solution and stored in artificial saliva for colour stabilization. The specimens were randomly divided into three groups (n = 36) according to the following protocols: (a) bleaching without desensitizer, (b) bleaching with prior application of sodium fluoride, and (c) bleaching with prior application of 5% potassium nitrate. After fabricating customized trays, desensitizers were applied for 10 minutes followed by 16% carbamide peroxide bleaching gel, which was in contact with the teeth for three hours. The bleaching efficacy was evaluated at baseline (after staining), 3rd day, 7th day, and 14th day using a digital spectrophotometer. Results There was an increase in the overall colour change (∆E) from baseline to 14th day, which was statistically significant at cervical, middle, and incisal thirds of the teeth between the three groups with the sodium fluoride group showing decreased ∆E. Conclusions Carbamide peroxide (16%) showed improved whitening efficacy from baseline to the 14th day with increasing median values at all time periods. The sodium fluoride group showed decreased ∆E value when compared to other groups.

Tooth Sensitivity After Dental Bleaching With a Desensitizer-containing and a Desensitizer-free Bleaching Gel: A Systematic Review and Meta-analysis

Objectives:

A systematic review and meta-analysis were performed to evaluate the risk and intensity of tooth sensitivity (TS) after dental bleaching with a desensitizer-containing and a desensitizer-free bleaching gel in adult patients. Color change and risk of gingival sensitivity was also evaluated.

Methods:

A comprehensive search was performed MEDLINE via PubMed, Scopus, Web of Science, Latin American and Caribbean Health Sciences Literature database (LILACS), Brazilian Library in Dentistry (BBO), EMBASE and Cochrane Library, and System for Information on Grey Literature in Europe (SIGLE) without restrictions to identify randomized clinical trials. Abstracts from the annual conference of the International Association for Dental Research (1990–2016), unpublished and ongoing trials registries, dissertations, and theses were also searched. The quality of the evidence was rated using the Grading of Recommendations: Assessment, Development and Evaluation (GRADE) approach.

Data:

After duplicates were removed, 1352 articles were identified. After title and abstract screening, only 47 studies remained for qualitative evaluation. Most of the studies had unclear risk of bias. No difference between groups were observed for the risk ratio of TS (risk ratio = 0.99; 95% confidence interval [CI] = 0.74–1.33); intensity of TS (standardized difference in means [SMD] = 0.04; 95% CI = 0.79–0.70); color change in shade guide units (SMD – 0.04; 95% CI = 0.50–0.42); color change in ΔE* (SMD = 0.41 (95% CI = 0.07–0.89); and risk ratio of gingival irritation (SMD = 1.05; 95% CI = 0.81–1.36). Except for the risk of TS, graded as moderate quality of evidence, all other outcomes were rated as low and very low quality.

Conclusions:

Incorporating desensitizers in the bleaching gel did not reduce the risk of TS, and the quality of this evidence was considered moderate. On the other hand, the intensity of TS, color change, and risk of gingival irritation was similar between groups, but the quality of the evidence for these outcomes was graded as low or very low, thus reducing the level of confidence in these outcomes.

Double-blind Randomized Study to Evaluate the Safety and Efficacy of Over-the-counter Tooth-whitening Agents Containing 2.9% Hydrogen Peroxide

OBJECTIVES

In this double-blind randomized study, we evaluated the safety and efficacy of over-the-counter (OTC) bleaching products that included 2.9% hydrogen peroxide (H₂O₂) with two methods of application: strip and paint-on.

METHODS AND MATERIALS

A commonly used product was selected for each type (strip and paint-on) of OTC bleaching agent. In total, 75 volunteers were assigned randomly into five groups: two test groups (strip and paint-on), two negative control groups (products without H₂O₂), and one positive control group (dentist-supervised home bleaching). The tooth shade was evaluated with a spectrophotometer and Vita shade guide at baseline and 2 weeks and 4 weeks after use. To document any adverse reactions, such as hypersensitivity or tissue irritation, all patients were examined and the Gingival Index (GI), Plaque Index (PI), and a visual analog scale (VAS) measuring the cold response were obtained.

RESULTS

There were significant differences among the five groups ( p<0.001). The positive control showed the greatest color changes; then, in decreasing order, the strip-type test group, paint-on-type test group, and negative controls. The strip-type bleaching agent was significantly more effective than the paint-on-type agent and the negative control, while it was significantly less effective than the dentist-supervised home bleaching. Regardless of the treatment group, the canines showed greater color changes than did the central or lateral incisors. Some cases of gingival irritation and hypersensitivity were observed, but they were mild and reversible. GI, PI, and VAS scores were not significantly changed.

CONCLUSIONS

Within the limitations of this study, the results indicated that the strip-type and paint-on-type OTC bleaching agents were significantly less efficacious than was dentist-supervised home bleaching; however, they showed acceptable safety and efficacy. The strip-type was more effective than was the paint-on-type in this study.

Randomized clinical trials of dental bleaching - Compliance with the CONSORT Statement: a systematic review

We reviewed the literature to evaluate: a) The compliance of randomized clinical trials (RCTs) on bleaching with the CONSORT; and b) the risk of bias of these studies using the Cochrane Collaboration risk of bias tool (CCRT). We searched the Cochrane Library, PubMed and other electronic databases, to find RCTs focused on bleaching (or whitening). The articles were evaluated in compliance with CONSORT in a scale: 0 = no description, 1 = poor description and 2 = adequate description. Descriptive analyses of the number of studies by journal, follow-up period, country and quality assessments were performed with CCRT for assessing risk of bias in RCTs. 185 RCTs were included for assessment. More than 30% of the studies received score 0 or 1. Protocol, flow chart, allocation concealment and sample size were more critical items, as 80% of the studies scored 0. The overall CONSORT score for the included studies was 16.7 ± 5.4 points, which represents 52.2% of the maximum CONSORT score. A significant difference among journal, country and period of time was observed (p < 0.02). Only 7.6% of the studies were judged at "low" risk; 62.1% were classified as "unclear"; and 30.3% as "high" risk of bias. The adherence of RCTs evaluating bleaching materials and techniques to the CONSORT is still low with unclear/high risk of bias.

Spectrophotometric and computerized evaluation of tooth bleaching employing 10 different home-bleaching procedures: In-vitro study

Objective:

The aim of this in-vitro study was to evaluate the efficacy of bleaching products, determine the applicability and validation of the measurement methods.

Materials and Methods:

Freshly extracted 110 human incisor teeth were stained with whole blood and hemolysate solution prior to the application of 10 different home-bleaching products. Spectrophotometric measurements of the tooth shades were performed for each specimen before and after bleaching at the 1^st, 3^rd, 7^th, and 14 days. Differences in lightness (Δl), chroma (Δc), hue (Δh) values and shade changes were measured to evaluate process. Computerized digital imaging analyses to determine the color changes were performed with Photoshop CS4 software (Adobe, San Jose, CA, USA). Statistical analyses were performed with analysis of variance, Scheffe and Tukey tests.

Results:

In all of the test groups regardless of the material used, a significant increase in lightness and hue, and decrease of chroma were observed, as compared to the control group. After recommended bleaching applications, Δl and Δh values respectively increased in group Zaris White and Brite (ZWB) and group Pola Night and Δc values showed significant decrease in groups ZWB and Rembrandt REM3 (P < 0.05). At the end of the procedure both spectrophotometric and digital imaging analysis showed ZWB was the most effective product among the others while Yotuel and Happy Smile were the least (P < 0.05).

Conclusions:

Home-bleaching systems showed slower but almost permanent bleaching effect likewise office-based methods. Both software and spectrophotometric analyses have advantages such as evaluating the results objectively and numerically, also treatment outcomes could be preserved.

A clinical study of the effectiveness of a light emitting diode system on tooth bleaching

The purpose of this study was to evaluate the efficacy of a Light Emitting Diode (LED) System (BriteWhite) on tooth bleaching. Method: eeth 11 and 21 of twenty one subjects were treated in the chair with a LED light and 44% carbamide peroxide gel, followed by an at-home treatment period of 14 days with 35% carbamide peroxide. The color of the teeth was measured with a spectrophotometer (L*; a*; b*) before treatment (control) and after the above mentioned two stages. The subjects were also instructed to note tooth and gingival sensitivity. Results: For the L* component a statistically significant difference (p<0.05) between base-line and directly after the LED treatment stage (whiter) was found and a complete relapse was found after the 14 day at-home treatment period. The b* component showed statistically significant differences (p<0.05) between base-line and the LED stage (less yellow more blue), with a further significant color improvement after the 14 day treatment period. For the a* component (green to red) no statistically significant change was (p>0.05) found throughout the study (Wilcox on Signed Rank Sum Test). A major color change of 1.8 units (ΔE_ab) was found after the LED treatment stage with only a further small 0.2 unit improvement after the 14 day at-home treatment stage. Tooth and gingival sensitivity scores were low (below mild) throughout the treatment stages. Conclusion: A major tooth color increase was found after the in-office LED/gel treatment stage and only an insignificant further improvement was noted after the additional 14 day at-home treatment period. Only low tooth and gingival sensitivity scores were found. A slight increase in both the sensitivity and gingival scores after the LED/gel activated stage could be observed. Overall the total color increase was low.

In-office vital bleaching with adjunct light

The use of light as an adjunct to in-office bleaching is a controversial topic in dentistry because of the equivocal outcomes of the research conducted in studies using light compared with no light treatment. The proper diagnosis and treatment planning of discolored teeth is of primary importance when managing the outcomes and setting expectations for patients undergoing in-office bleaching with supplemental light. Although no study is conclusive on all bleaching lights, research evidence provides guidelines for the responsible use of in-office bleaching lights in dentistry.

A clinical study of the effectiveness of two different 10% carbamide peroxide bleaching products: a 6-month followup

The purpose of this study was to evaluate the efficacy of two different 10% carbamide peroxide bleaching products just after treatment and after a 6-month follow-up period. Methods. Two 10% carbamide peroxide products (Opalescence PF and Nite White ACP) were applied nightly for 14 days, according to the manufacturers' instructions. The color of teeth 11 and 21 of thirty-four subjects having A2 or darker teeth were measured with a spectrophotometer (L^∗; a^∗; b^∗) before treatment, just after treatment (14 days) and after 6 months. Results and Conclusions. Both products produced significant whitening of teeth with total color change (ΔE_ab^∗) of approximately 5.20 units. There was a significant improvement in all 3 color coordinates (L*, a*, and b^∗) for up to 6 months postbleaching (P < .05). Nite White showed a higher degree of relapse (27%) than Opalescence (18%) over the 6-month period. It is suggested that rebleaching after 6 months is not necessary.

In vivo Spectrophotometric Assessment of the Tooth Whitening Effectiveness of Nite White 10% with Amorphous Calcium Phosphate, Potassium Nitrate and Fluoride, Over a 6-month Period

To clinically evaluate the effectiveness of Nite White 10% carbamide peroxide with amorphous calcium phosphate, potassium nitrate and fluoride over a 6-month follow-up period. Nite White was applied nightly for 14 days, according to the manufacturer's instructions. The color of teeth 11 and 21 of twenty one subjects was measured with a spectrophotometer (L(*); a(*); b(*)). Subjects were instructed to take note of any tooth sensitivity and gingival irritation. For all three components (L(*), a(*) and b(*)) statistical significant differences (p<0.05) in the values between base-line (pre-bleaching) and; after treatment, after 1-month, after 3-months as well as after 6-months were found (Wilcoxon Signed Rank Sum Test). Significant differences were also found amongst the ΔE(*) (ab) (0-14days) values and; ΔE(*) (ab) (0-1 month), ΔE*(ab) (0-3 months) and ΔE(*) (ab) (0-6 months). However, no significant differences were found between pairs of ΔE(*) (ab) (0-1 month), ΔE(*) (ab) (0-3 months) and ΔE(*) (ab) (0-6months). The decrease in ΔE(*) (ab) was the highest after 1 month (~30%). The highest decrease in L(*) was about 58% after 1 month. Over the 14-day treatment period tooth sensitivity was 24.5%.

CONCLUSIONS

Nite White ACP demonstrated significant tooth-whitening (unit increase = 5.29) with a low tooth sensitivity (25%) probably due to the presence of amorphous calcium phosphate, potassium nitrate, and fluoride. The whitening effect decreased the most after one month and then maintained well even after a 6 month period (units 3.89).

CLINICAL IMPLICATIONS

The product is a good tooth whitener with a color increase of about 5 units accompanied with a low sensitivity.

Clinical evaluation of a dental color analysis system: the Crystaleye Spectrophotometer®

PURPOSE

To evaluate the clinical performance of the Crystaleye Spectrophotometer(®), a dental color analysis system.

METHODS

Three color-measuring devices (Crystaleye Spectrophotometer(®), CAS-ID1, MSC-2000) were tested and the differences in color measurements among them were evaluated using Scheffe's F-test. Color measurements with the Crystaleye Spectrophotometer(®) were repeated 10 times by the same operator. The color difference (ΔE) between the first and tenth measurements was calculated. The Crystaleye Spectrophotometer(®) was used to measure the color of the maxillary left central incisor under two conditions (light and dark) and the effect of exterior lighting was analyzed to assess the accuracy of measurements. Furthermore, five different operators performed color measurements, and ΔE among the three devices was calculated. The ΔE between the target tooth and the crown of a single maxillary central incisor crown fabricated using data from the Crystaleye Spectrophotmeter(®) was calculated. Color differences between prebleaching and postbleaching were also analyzed with the Crystaleye Spectrophotometer(®) using the parameters ΔE, ΔL*, Δa*, and Δb*.

RESULTS

The data from the three spectrophotometers were not significantly different. The ΔE during repeated color measurements by the same operator was 0.6. The ΔE between light and dark conditions was 0.9. The data from the five operators were not significantly different. The mean ΔE value between the target tooth and the fabricated crown was 1.2 ± 0.4, and the mean ΔE value between prebleaching and postbleaching was 3.7 ± 1.0.

CONCLUSIONS

The Crystaleye Spectrophotometer(®) is an easy-to-use color analysis system producing accurate color measurements under clinical conditions.

Clinical performance of vital bleaching techniques

This study compared the clinical outcome of bleaching techniques in vital teeth. After IRB approval and informed consent, 90 subjects were selected based on the shade of their anterior teeth (A2 or darker, Vita Classic shade guide). Subjects were assigned to three treatment groups in a split-mouth study design: Group I: HB (at-home bleaching with 10% carbamide peroxide for two weeks) vs OBL (in-office bleaching with 35% hydrogen peroxide, two sessions, two-week intervals, with light irradiation); Group II: OB (in-office bleaching without light irradiation) vs OBL; Group III: HB vs combination (one session plus HB). Color change and color rebound (deltaE) were measured for a 16-week period. Color measurements were carried out with both a spectrophotometer and a shade guide at baseline, 1, 2, 4, 8 and 16 weeks. Tooth sensitivity was evaluated using a VAS scale for 15 days. Both the Student's t-test and Tukey-Kramer test were used to analyze the results (p < 0.05). After one week, one session of OBL followed by HB resulted in lower color values, compared with the other bleaching methods. Group III resulted in the least shade values at one-week evaluation, when compared with the other bleaching methods. After two weeks, HE alone resulted in similar color changes as OB, OBL and OBL+HB. The use of light irradiation did not improve bleaching efficacy (OB = OBL). OBL and OB resulted in higher sensitivity rates than HB.

Color change of vital teeth exposed to bleaching performed with and without supplementary light

OBJECTIVES

The aim of this clinical study was to evaluate tooth color change after exposure to 25% hydrogen peroxide in-office tooth whitening system, with and without supplementary light exposure.

METHODS

Twenty subjects were treated with two separate 45-min exposures of bleach, with and without light using an opposing-arch design. Visual and instrumental color measurements were obtained from eighty teeth before bleaching and seven days after treatment using two different shade guides, Vitapan Classical (VC), Vita Bleachedguide 3D-Master (BG) and an intraoral spectrophotometer. Data were analyzed using ANOVA, paired t-test, and Wilcoxon signed rank tests at the 0.05 level of significance.

RESULTS

Instrumental method revealed significant difference in color between treatment with light (DeltaE(ab)(*)=6.0) and without light (DeltaE(ab)(*)=4.7) after seven days (p<0.05). No differences were visually detected between treatment with light and without light using the VC (p=0.56). However, a significant difference was recorded using the BG (p<0.01). Instrumental measurements of color change were in better accordance with visual findings using the BG guide (R(2)=0.60) rather than the VC (R(2)=0.20).

CONCLUSIONS

Within the limitations of this study, the treatment with supplementary light showed significantly greater bleaching-dependent changes in color compared to treatment without light when assessed using instrumental methods. The same was determined for the visual method with Vita Bleachedguide 3D-Master. No significant difference in color change with respect to light exposure was detected for the Vitapan Classical.

In vitro evaluation of the effectiveness of bleaching agents activated by different light sources

PURPOSE

This study evaluated the efficacy of tooth whitening and color stability at different time periods after treatment.

MATERIALS AND METHODS

Blocks obtained from human molars were divided into 15 groups (n = 5) by bleaching agents: 35% hydrogen peroxide (Whiteness HP and Opalescence Xtra) and 37% carbamide peroxide (Whiteness Super); and light sources: halogen lamp and plasma arc lamp (bleach mode), LED/diode laser, argon laser, and no light source. The efficacy of bleaching was measured using a spectrophotometer. Six bleaching sessions were performed (times 1 to 6). The specimens were submitted to another reading 7, 15, and 30 days after the end of bleaching (times 7, 8, and 9). The results were submitted to ANOVA followed by Tukey test and polynomial regression (p < 0.05).

RESULTS

Carbamide peroxide significantly differed from hydrogen peroxide, presenting low reflectance values. Activated versus non-activated bleaching did not differ significantly for any gel tested, except for Whiteness HP activated by argon laser, which presented the lowest mean reflectance values. The results obtained with hydrogen peroxide revealed a decrease in reflectance values one month after the end of treatment. For carbamide peroxide, this decrease was not observed.

CONCLUSION

The halogen lamp presented the same or higher efficacy than non-activated bleaching, which had a longer gel contact period. When hydrogen peroxide was used, a decrease in reflectance values was observed 30 days after the end of bleaching.

Ex vivo evaluation of the effectiveness of bleaching agents on the shade alteration of blood-stained teeth

AIM

To evaluate ex vivo effectiveness of the three formulations of bleaching materials for intracoronal bleaching of root filled teeth using the walking bleach technique.

METHODOLOGY

Extracted premolar teeth were stained artificially with human blood. After biomechanical preparation, the root canals were filled and a 3-mm thick intermediate base of zinc phosphate cement was placed at the level of the cementoenamel junction. The teeth were divided into four groups (n = 12): C (control, without bleaching material), A1 (sodium perborate + distilled water), A2 (sodium perborate + 10% carbamide peroxide) and A3 (sodium perborate + 35% carbamide peroxide). The bleaching materials were changed at 7 and 14 days. Evaluation of shade was undertaken with aid of the VITA Easyshadetrade mark (DeltaE*ab) and was performed after tooth staining and at 7, 14 and 21 days after bleaching, based on the CIELAB system. Data were analysed by anova for repeated measurements, Tukey and Dunnett tests (alpha = 0.05).

RESULTS

The Tukey test revealed that group A1 (10.58 +/- 4.83 DeltaE*ab) was statistically different from the others (A2, 19.57 +/- 4.72 DeltaE*ab and A3, 17.58 +/- 3.33 DeltaE*ab), which were not different from each other. At 7 days: A1 was significantly different from A2; at 14 and 21 days: A2 and A3 were significantly better than A1; the Dunnett test revealed that the control group was different from A1, A2 and A3 at all periods (P < 0.05).

CONCLUSION

Sodium perborate associated with both 10% and 35% carbamide peroxide was more effective than when associated with distilled water.

New Shade Guide for Evaluation of Tooth Whitening?Colorimetric Study

STATEMENT OF THE PROBLEM

Available shade guides lack colorimetric uniformity, which compromises the validity of visual evaluation of tooth whitening efficacy.

PURPOSE

The objective of this study was to perform a colorimetric analysis of a new shade guide designed primarily for the visual evaluation of tooth whitening efficacy and to compare this shade guide with two commercial shade guides.

MATERIALS AND METHODS

Color ranges and color distribution of three shade guides (prototype of the new Vita Bleachedguide 3D-Master [BG, Vita Zahnfabrik, Bad Säckingen, Germany], value scale of Vitapan Classical [VC, Vita], and color-ordered Trubyte Bioform porcelain shade guide [TB, Dentsply International, York, PA, USA]) were analyzed (N=3). A circular area (d=1.7 mm) on the middle of the labial surface of the tab, excluding the cervical portion, was measured with a spectroradiometer (D65, 2). Whiteness and yellowness indices were computed. Data were analyzed by analysis of variance and Fisher's PLSD test at a 0.05 level of significance.

RESULTS

The range of color difference (DeltaE*) from the lightest to the darkest tab was 33.8 (BG), 17.1 (VC), and 23.2 (TB). Mean values of DeltaE* among pairs of adjacent tabs were 3.0 (BG), 4.2 (VC), and 3.3 (TB). BG exhibited the highest R2 values between color coordinate pairs and between whiteness and yellowness indices with the respective color coordinates.

CONCLUSIONS

BG exhibited the widest color range and had the most consistent color distribution as compared with the two commercial products. Extension of the lightness range of BG toward higher L* values (bleach shades) was confirmed.

CLINICAL SIGNIFICANCE

A dental shade guide that is colorimetrically uniform might increase the reliability of visual comparisons of tooth whitening efficacy, whereas the inclusion of realistic bleaching shades in the shade guide will complement contemporary esthetic dentistry.

Home-based chemically-induced whitening of teeth in adults

BACKGROUND

During the last decade tooth whitening products have become widely available in the USA for sale over-the-counter or dispensed by dentists for use at home. With the current rapid growth in demand for tooth whitening it is imperative that the dental community base its recommendations to patients on sound scientific evaluations conducted in well-designed and independent studies.

OBJECTIVES

To evaluate the effectiveness (versus a placebo or another active product) and side effects of over-the-counter or dentist-dispensed chemically-based tooth whitening products designed for home use.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2005, Issue 3); MEDLINE (January 1966 to September week 2 2005); and EMBASE (1988 to week 39 2005). The tables of content of selected dental journals published since 1995 were searched for additional references. Written requests for additional studies and information were mailed to experts in this area of research. After a final set of studies was identified, the list of references reported in the included reports was reviewed to identify additional studies. Studies published in English and non-English were considered in this review.

SELECTION CRITERIA

Randomised controlled trials and quasi-randomised controlled trials of dentist-dispensed or over-the-counter tooth whitening products with a chemical action (rather than abrasive action), for home use.

DATA COLLECTION AND ANALYSIS

Screening of titles and abstracts, data extraction and quality assessment were undertaken independently and in duplicate.

MAIN RESULTS

A total of 416 articles were identified, 25 of which met the inclusion criteria and presented data that could be used in the analysis. All included trials measured effectiveness immediately after 2 weeks of product application. Only 13 studies reported outcome data 1 week after the 2-week application period, and of those only six reported outcome data after 1 month or longer. Four of the included trials were assessed as at moderate risk of bias and the remainder at high risk of bias. All trials were sponsored by the manufacturers of tooth whitening products. Six trials compared different whitening products (gel in trays, paint-on films and whitening strips) with placebo/no treatment and all analyses showed the products to be effective, although most comparisons were based on single trials. Nineteen trials compared different whitening products with each other. There was only one meta-analysis which included more than one trial which showed statistically significant differences between the different whitening products. Strips (5.5% to 6.5% hydrogen peroxide(HP)) are more effective than gel in tray at 10% carbamide peroxide (CP) mean difference 1.82 (95% confidence interval (CI) 0.26 to 3.38). All of these trials were assessed as of high risk of bias. 'Mild' to 'moderate' tooth sensitivity and gingival irritation were the most common side effects. The whitening strips and products with high concentrations of HP caused more users to complain from tooth sensitivity. The protocols for preparation of participants prior to bleaching were inconsistent among the studies. Data on baseline scores of whiteness were not reported by the majority of the studies. The current evidence base on tooth whitening products suffers from methodological and publication biases.

AUTHORS' CONCLUSIONS

There is evidence that whitening products work when compared with placebo/no treatment. There are differences in efficacy between the products, mainly due to the levels of active ingredients, hydrogen peroxide and carbamide peroxide. All trials were however short term and the majority of the studies were judged to be at high risk of bias and were either sponsored or conducted by the manufacturers. There is a need for pragmatic long-term and independent clinical studies that include participants representing diverse populations. There is also a need to evaluate long-term harms. Several studies reported (where measured) the common side effects of tooth sensitivity and gingival irritation, and people should be informed of this.