Bleaching toothpaste with two different concentrations of hydrogen peroxide: A randomized double-blinded clinical trial

Over-the-counter products in tooth bleaching: A scoping review

OBJECTIVE

To map and summarize the current scientific evidence concerning the active ingredients, effectiveness, and adverse effects of over-the-counter (OTC) bleaching products.

DATA AND SOURCE

This study was conducted according to the PRISMA-ScR guidelines for scoping reviews and registered on the Open Science Framework platform.

STUDY SELECTION

Database searches were conducted in PubMed/MEDLINE, Embase, and Scopus up to January 2024. All in vitro, in situ, and clinical studies evaluating the effectiveness and adverse effects of OTC bleaching products were included. A descriptive analysis of the included studies was performed.

RESULTS

A total of 88 studies were included. Most of them were in vitro studies (n = 49), followed by randomized clinical trials (n = 28). The main OTC bleaching products identified were whitening or stain-removing toothpastes (n = 42), followed by whitening strips (n = 39). Most clinical studies indicate that whitening strips are effective in improving tooth color and providing whitening benefits. In contrast, the bleaching effectiveness of toothpastes, mouth rinses and whitening trays was mainly supported by in vitro studies. The main adverse effects associated with OTC bleaching agents were tooth sensitivity and gingival irritation.

CONCLUSION

A wide variety of OTC bleaching products is available for consumer self-administered use. Clinical studies have mainly confirmed the bleaching effectiveness of whitening strips, while the validation for toothpastes, mouth rinses and whitening trays has mainly relied on in vitro studies. Nevertheless, the use of OTC bleaching products may result in adverse effects, including tooth sensitivity, gingival irritation, and enamel surface changes.

CLINICAL SIGNIFICANCE

Some over-the-counter bleaching products may have whitening properties supported by clinical studies, particularly those containing hydrogen or carbamide peroxide. Nonetheless, clinicians must be aware of the potential risks associated with excessive self-administration of these products, which may result in adverse effects.

Evaluating the efficiency of two different over-the-counter tooth whitening systems: a randomised controlled clinical trial

OBJECTIVES

To compare whitening efficiency and tooth sensitivity (TS) of two different over the counter (OTC) whitening systems in comparison to conventional at-home bleaching using 20% carbamide peroxide.

MATERIALS AND METHODS

A randomised controlled clinical trial was conducted with three parallel groups (n = 13): (A) at-home whitening using 20% carbamide peroxide (20% CP), (B) OTC ready-to-use gel trays and (C) OTC-paint on gel. Clinical colour change values (ΔE) were measured using spectrophotometry at T0: baseline, T1: 7-day and T2: 14-day from whitening start, T3: 2 weeks and T4: 6 months after whitening end. TS was recorded using a visual analogue scale (VAS). ΔE and TS values were statistically analysed. The level of significance for all tests was 5%.

RESULTS

Significant differences in ∆E values were recorded between the experimental groups. ∆E values were significantly higher in the 20% CP conventional at-home whitening group. TS measurements were significantly higher in the 20% CP whitening group (p < 0.05).

CONCLUSION

Conventional at-home whitening revealed significantly improved colour change when compared to the OTC-paint on gel and OTC ready-to-use gel tray whitening systems. There was a significant colour relapse in OTC systems.

CLINICAL RELEVANCE

The use of tested OTC systems is not recommended as they are not effective in a clear and prolonged improved shade change. Conventional at-home whitening using 20% CP showed higher whitening efficiency and colour stability. This trial was registered with a International Standard Randomised Controlled Trial Number (ISRCTN23096480), Registration date: 12/04/2023.

Evaluation of Relative Dentin Abrasivity in Whitening Toothpastes Containing Acids

INTRODUCTION AND AIMS

This study aimed to evaluate the relative dentin abrasivity of whitening toothpastes containing acids using the Radioactive Dentin Abrasivity - Profilometry Equivalent (RDA-PE).

METHODS

A total of 100 bovine dentin specimens were prepared and assigned to the following groups (n = 10): 5 hydrogen peroxide (HP) whitening toothpastes (WTH1-WTH5) with or without acid (citric acid, ethylenedinitrilotetraacetic acid disodium, and phosphoric acid), 2 whitening toothpastes with silica and containing citric or phosphoric acid (WTS1 and WTS2), one conventional toothpaste (CT), and 2 reference slurries (RS). All specimens were brushed for 4,000 or 10,000 strokes using toothbrush and toothbrushing machine. The average dentin depth was measured using a noncontact profilometery, and the RDA-PE value was calculated based on the RS. The pH of the solution, average particle size, particle content, and particle hardness were measured. The RDA-PE data were analysed using one-way analysis of variance and Tukey's test, and the effects of the 4 measured factors on RDA-PE were investigated via multiple regression analysis.

RESULTS

The RDA-PE values of the HP whitening toothpastes (mean value: 19-46) were significantly lower, whereas those of the silica whitening toothpastes (80 or 111) were similar to those of the RS after 4,000 strokes (100). The RDA-PE values of all whitening toothpastes were significantly lower than the RS values after 10,000 strokes (242). The HP whitening toothpastes were slightly acidic (pH ≤6) compared to the other solutions. The HP (2.9%-3.7%) and silica (8.9% or 9.9%) whitening toothpastes had significantly lower particle content than RS (16.6%). The particle content significantly influenced the RDA-PE values by multiple regression results.

CONCLUSIONS

The RDA-PE values of whitening toothpastes varied. The particle content in the solution was a key factor affecting the RDA-PE value.

CLINICAL RELEVANCE

Whitening toothpastes containing acids did not cause significant dentin abrasion.

Analysis of Covarine Particle in Toothpaste Through Microfluidic Simulation, Experimental Validation, and Electrical Impedance Spectroscopy

Covarine, copper phthalocyanine, a novel tooth whitening ingredient, has been incorporated into various toothpaste formulations using diverse technologies such as larger flakes, two-phase pastes, and microbeads. In this study, we investigated the behavior of covarine microbeads (200 μm) in Colgate advanced white toothpaste when mixed with artificial and real saliva. Our analysis utilized a custom-designed microfluidic mixer with 400 μm wide channels arranged in serpentine patterns, featuring a Y-shaped design for saliva and toothpaste flow. The mixer, fabricated using stereolithography 3D printing technology, incorporated a flexible transparent resin (Formlabs' Flexible 80A resin) and PMMA layers. COMSOL simulations were performed by utilizing parameters extracted from toothpaste and saliva datasheets, supplemented by laboratory measurements, to enhance simulation accuracy. Experimental assessments encompassing the behavior of covarine particles were conducted using an optical profilometer. Viscosity tests and electrical impedance spectroscopy employing recently developed all-carbon electrodes were employed to analyze different toothpaste dilutions. The integration of experimental data from microfluidic chips with computational simulations offers thorough insights into the interactions of covarine particles with saliva and the formation of microfilms on enamel surfaces.

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

OBJECTIVES

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

METHODOLOGY

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

RESULTS

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

CONCLUSIONS

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

Effects of a commercial whitening toothpaste containing hydrogen peroxide and citric acid on dentin abrasion and erosion

BACKGROUND

Hydrogen peroxide (HP) and citric acid (CA), key contributors to toothpaste acidity, can lead to dental loss. This study aimed to compare the amount of abrasion or loss of dentin based on pH, buffering, and concentration of HP and CA in commercial and experimental toothpastes after toothbrushing or immersion.

METHODS

Bovine dentin specimens were randomly assigned to nine solutions. The prepared solutions included two commercial toothpastes (whitening toothpaste [WT] with HP and CA; conventional toothpaste [CT] without HP and CA), reference slurry (RS), two CA solutions (1.92%, CAS1; 0.001%, CAS2), basic solution (7.16% sodium phosphate dibasic [SPDS]), CA phosphate buffer solution (3.58% SPDS and 0.96% CA [CAPB]), HP solution (4%, HPS), and distilled water (DW). Dentin specimens were performed in two treatments: one with only abrasion (10,000 brushings) and one with only immersion (1 h). After treatments, the amount of dentin loss and surface images were measured and observed using noncontact profilometry. Data were analyzed using an one-way analysis of variance and the Tukey test as a post hoc analysis (p < 0.05).

RESULTS

WT with pH 5.0 had lower dentin abrasion than CT and RS after brushing but had higher dentin loss than both after immersion. The dentin surfaces of CAS1, CAPB, and WT were damaged after immersion, whereas HPS, CAS2, CT, SPDS, RS, and DW remained intact after soaking. CAS2 and HPS, which had a pH of 5.0 like WT, did not significantly differ from those of DW after brushing.

CONCLUSIONS

WT containing HP and CA did not cause significant dentin abrasion but may cause additional dentin loss even without brushing. After brushing or immersion, the CA concentration may affect the dentin surface more than the HP concentration included in WT. The amount of abrasion or loss of dentin after brushing or soaking can vary based on the composition, concentration, and buffer in the solution, even if the pH of the solution is similar to pH 5.0.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CLINICAL SIGNIFICANCE

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

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

OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

CLINICAL RELEVANCE

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

Effect of an experimental desensitizing gel on bleaching-induced tooth sensitivity after in-office bleaching—a double-blind, randomized controlled trial

OBJECTIVES

To evaluate the risk and intensity of tooth sensitivity (TS), and the efficacy of in-office bleaching after applying an experimental desensitizing gel composed of 10% calcium gluconate, 0.1% dexamethasone acetate, 10% potassium nitrate, and 5% glutaraldehyde.

MATERIAL AND METHODS

In a split-mouth, double-blind, placebo-controlled study, 50 participants had their upper hemiarches randomized into experimental and placebo groups. Desensitizing and placebo gels were applied for 10 min before in-office bleaching (35% hydrogen peroxide, 1 × 50 min; two bleaching sessions; 1-week interval). TS was recorded immediately after bleaching, 1, 24, and 48 h after each session, with a 0-10 visual analogue scale (VAS) and a five-point numerical rating scale (NRS). The color was recorded in all groups at baseline, 1 week after each session, and 1 month after the end of bleaching using shade guide units (ΔSGUs) and a spectrophotometer (ΔE_ab, ΔE₀₀, and ΔWI_D).

RESULTS

Most participants (96%) felt some discomfort during treatment regardless of the study group. The odds ratio for pain was 0.65 (95% CI 0.1 to 4.1; p = 1.0). The intensity of TS did not differ between groups (p > 0.31), and it was only 0.34 VAS units lower in the experimental group. A significant color change occurred in both groups regardless of the group.

CONCLUSIONS

The desensitizing experimental gel applied before in-office bleaching did not reduce the risk and the intensity of TS and did not affect color change.

CLINICAL RELEVANCE

Although the experimental desensitizing agent with varying mechanisms of action did not jeopardize the color change, it did not reduce the risk or intensity of in-office bleaching.

CLINICAL TRIAL REGISTRATION NUMBER

RBR-7T7D4D.

Tooth whitening with an experimental toothpaste containing hydroxyapatite nanoparticles

Background

The aim of this study was to evaluate the postbrushing tooth-whitening effect of toothpaste containing hydroxyapatite nanoparticles (nano-HAPs). The impact of the concentration on the whitening performance of nano-HAP toothpaste was also investigated.

Methods

Two concentrations of nano-HAP (10 wt% and 1 wt%) were incorporated in nonabrasive toothpastes. Forty bovine incisors were randomly assigned into four groups: 10 wt% nano-HAP, 1 wt% nano-HAP, toothpaste without nano-HAP as a negative control and water as a blank control. Each tooth was treated with the toothpaste three times and hydrodynamic shear force (HSF) once. The teeth surfaces were observed by SEM after each application. Tooth color (L*, a* and b* values) was measured by a spectrophotometer, and color changes (△E, △L, △a and △b values) were calculated. Two-way mixed ANOVA was performed to evaluate the influence of the concentration and repeated application on the tooth-whitening effect of nano-HAP.

Results

We found that nano-HAP-treated enamel exhibited higher L* values and lower a* and b* values than the control groups (P < 0.05). The 10 wt% nano-HAP group showed significantly higher △E values than the 1 wt% nano-HAP group (P < 0.05). After three applications, the △E mean value of the 10 wt% nano-HAP group was 4.47. The △E and △L values were slightly reduced after HSF (P < 0.05). For both nano-HAP groups, HAP single crystallites and agglomerates were identified, and their sizes grew with nano-HAP reapplication.

Conclusions

In conclusion, nano-HAP toothpaste has a satisfying postbrushing whitening effect and good resistance to mechanical forces. The whitening effect seemed to be concentration-dependent.

Effectiveness and Adverse Effects of Over-the-Counter Whitening Products on Dental Tissues

The role of bleaching agents (e.g., hydrogen peroxide) in tooth bleaching is quite well-described in a few literature studies and considered as the option choice for those desiring brighter teeth, but alternative methods have emerged to fulfill the desire of patients in a faster, easier, and cheaper way. In this context, whitening over-the-counter (OTC) products are available in several vehicles, such as toothpaste, rinses, gums, paint-on varnishes, and strips, but their effectiveness in terms of bleaching is questioned. This review aimed to describe their mode of action, whitening effectiveness, and harmful effects associated with the indiscriminate use of these products. Dentifrices usually present a combination of abrasives that can induce damage to the tooth surface without evidence of promoting real bleaching. The same was found for rinses, which might present a low pH, with an erosive potential. Charcoal has been included in the composition of these products to improve their whitening effect but there is no evidence supporting it. Regarding strips, they present hydrogen peroxide in a variety of concentrations and are the only OTC products able to promote bleaching. Despite the vehicle, an indication for the use of these products should be made after a careful individual diagnosis of the etiology of the dental staining, considering that most of them seem to be effective only in removing extrinsic stains or preventing their formation over enamel. Also, their indiscriminate use might induce damage and deleterious effects over tooth tissues or gingival tissues. The dentist should be aware of the composition and mode of action of each individual product as they change according to the composition and the vehicle used to recommend the best mode of usage. Still, there is no sound evidence that any of the described OTC products promote a better bleaching effect than the products indicated for a professional.