Longevity, effectiveness, safety, and impact on quality of life of low-concentration hydrogen peroxides in-office bleaching: a randomized clinical trial

In-office Bleaching Activated With Violet LED: Effect on Pulpal and Tooth Temperature and Pulp Viability

OBJECTIVES

This study evaluated the influence of hydrogen peroxide (HP) with or without titanium dioxide nanotubes (TiO2) associated with violet LED (VL) regarding: a) the temperature change in the pulp chamber and facial surface; b) the decomposition of HP; and c) the cytotoxicity of the gels on pulp cells.

METHODS AND MATERIALS

The experimental groups were: HP35 (35% HP/Whiteness HP, FGM); HP35+VL; HP35T (HP35+TiO2); HP35T+VL; HP7 (7.5% HP/White Class 7.5%, FGM); HP7+VL; HP7T (HP7+TiO2); and HP7T+VL. TiO2 was incorporated into the bleaching gels at 1%. Eighty bovine incisors were evaluated to determine temperature change in 8 experimental groups (n=10/group). A k-type thermocouple was used to evaluate the temperatures of the facial surface and in the pulp chamber, achieved by enabling endodontic access to the palatal surface, throughout the 30-minute session. HP decomposition (n=3) of gels was evaluated by using an automatic potentiometric titrator at the initial and 30-minute time points. Trans-enamel and trans-dentinal cell viability were assessed with a pulp chamber device as well as enamel and dentin discs (n=6), and the treatment extracts (culture medium + diffused components) were collected and applied to MDPC-23 odontoblast cells to evaluate cell viability according to the MTT test.

RESULTS

A temperature increase in the pulp chamber was observed in the presence of VL at 30 minutes (p<0.05) (Mann-Whitney test). Also at 30 minutes, HP35 showed greater decomposition in the presence of VL rather than in its absence (p<0.05) (mixed linear models and the Tukey-Kramer test). HP7 provided greater cell viability than the groups treated with HP35 (p<0.05) (generalized linear models test). Cell viability was significantly lower for HP7 in the presence of VL (p<0.05).

CONCLUSION

Pulpal temperature increased with VL (maximum of 1.9°C), but did not exceed the critical limit to cause pulp damage. Less concentrated HP resulted in higher cell viability, even when associated with VL.

Preemptive use of ibuprofen and desensitizer decreases immediate tooth sensitivity after in-office bleaching: A triple-blind, randomized, placebo-controlled clinical trial

BACKGROUND

The authors evaluated the synergistic analgesic effect of preemptive administration of 400 mg of ibuprofen (IBU) and potassium fluoride 2% (KF2), both in isolation or combination, on the painful perception of tooth sensitivity after tooth bleaching.

METHODS

Fifteen patients participated in this triple-blind, randomized, placebo-controlled clinical trial. The study used a crossover design for drug administration and a split-mouth design for desensitizer agent. Four paired groups were formed: IBU plus KF2 (IBU + KF2); IBU (IBU + placebo KF); KF2 (placebo IBU + KF2), and placebo (placebo IBU + placebo KF). The outcome measure was the perception of tooth sensitivity, assessed using a visual analog scale. Data were collected at 4 different times: immediately after tooth bleaching (baseline) and after 6, 30, and 54 hours. Statistical analysis was performed using the Friedman test and relative risk.

RESULTS

IBU plus KF2 was found to be more effective in reducing tooth sensitivity immediately after bleaching (baseline) compared with the placebo group (P < .05). The risk of experiencing moderate or severe tooth sensitivity was approximately 4 times higher in the placebo group than in the IBU plus KF2 group (relative risk, 4.00; 95% CI, 1.01 to 15.81; P = .025).

CONCLUSIONS

The combined use of 400 mg of IBU and KF2 appears to be beneficial in managing postbleaching tooth sensitivity. It provides a superior analgesic effect compared with placebo.

PRACTICAL IMPLICATIONS

The preemptive administration of IBU plus KF2 reduces tooth sensitivity after tooth whitening when compared with placebo. This clinical trial was registered in the Brazilian Clinical Trials Registry Platform. The registration number is U1111-1249-8191.

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.

Effect of whitening toothpastes and activated charcoal powder on enamel wear and surface roughness

This study aimed to evaluate surface roughness (Sa), roughness profile (Rv), and enamel wear after brushing with different whitening toothpastes and charcoal powders. Sixty (n = 10) bovine enamel blocks (6 × 6 × 3 mm) were randomly distributed into six groups according to toothpaste type: regular toothpaste (CONT), toothpaste containing 2% hydrogen peroxide (HP), toothpaste containing titanium dioxide (TiO2), toothpaste containing charcoal (COAL), toothpaste containing charcoal and TiO2 (COAL+TiO2), and activated charcoal powder (COAL_PWD). Each block was subjected to 30,000 reciprocal cycles at a 1:3 proportion slurry. After brushing, the blocks were analyzed using an optical profilometer to determine Sa, Rv, and enamel wear. In addition, representative 3D images of each group and wear profiles were obtained. Sa was analyzed using generalized linear models followed by Bonferroni correction, whereas Rv was analyzed using one-way analysis of variance. After brushing, COAL and COAL+TiO2 showed higher Sa values than COAL_PWD. However, no significant difference was observed in Sa between whitening toothpaste and COAL_PWD, and CONT (p > 0.05). In addition, no differences were observed among the groups in Rv (p > 0.05). Conversely, enamel wear was higher for TiO2, COAL, COAL+TiO2, and COAL_PWD than for CONT. CONT showed the least enamel wear, whereas HP showed intermediate values. Representative 3D images and line profiles showed lower step-height and lower mean surface losses for the CONT and HP groups than for the other groups. Whitening toothpastes and COAL_PWD did not increase Sa or Rv compared with CONT, while CONT demonstrated lower enamel wear.

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 Use of Diode Low-Power Laser Therapy before In-Office Bleaching to Prevent Bleaching-Induced Tooth Sensitivity: A Clinical Double-Blind Randomized Study

INTRODUCTION

The present study aimed to investigate the effectiveness of low-level laser therapy (LLLT) use before in-office bleaching to prevent an increase in the risk and intensity of tooth sensitivity.

METHODS

Thirty patients were selected. Before bleaching with 38% hydrogen peroxide, the participants were randomly divided into two groups of 15 subjects. Test group: the patients' teeth were subjected to a preliminary LLLT procedure by an 810 nm diode laser with 0.5 W for 30 s for an energy density of 15 J/cm² and a group placebo. All patients were instructed to report their cold sensitivity experiences immediately, 1 h, 24 h, and 48 h after the end of bleaching via a VAS score.

RESULTS

The results obtained show an increase in VAS values for both groups (290 and 490 vs. 224 and 234 of baseline time of test and placebo group, respectively); afterward, the VAS value seemingly decreases at 1 h after the end of bleaching, approaching the baseline VAS for the test group (274) in comparison to the placebo group.

CONCLUSIONS

The use of preliminary diode LLLT could represent a valid possibility to reduce the occurrence of tooth sensitivity post-whitening and shorten recovery time in cases where tooth sensitivity occurs.

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.

Physicochemical evaluation of hydrogen peroxide bleaching gels containing titanium dioxide catalytic agent, and their influence on dental color change associated with violet LED

BACKGROUND

The purpose of this study was: 1) to analyze the physical-chemical properties of hydrogen peroxide (HP) agents at 7.5% (HP7) and 35% (HP35), and the association with or without TiO₂ nanotubes; 2) to evaluate dental bleaching effectiveness by using HP7 and HP35 together with or without TiO₂ nanotubes, and applied with or without violet LED (VL).

METHODOLOGY

80 bovine incisors were treated according to groups (n = 10): HP35; HP35 + VL; HP35T (HP35 + TiO₂); HP35T + VL; HP7; HP7 + VL; HP7T (HP7 + TiO₂); HP7T + VL. Bleaching effectiveness was measured at 4 time points according to the Vita Classical, CIEL*a*b*, CIEDE2000, and WI_D parameters. HP35, HP35T, HP7, and HP7T were evaluated for mass change, pH, mean particle size (P), polydispersity (PDI), and zeta potential (ZP), over 6 months of storage.

RESULTS

The pH of HP35 thickener was higher when associated to TiO₂. At baseline, both of the bleaching gels containing TiO₂ had lower P, PDI, and PZ (p < 0.05). All groups showed a significant decrease in Vita Classical color scores (p = 0.0037). There was a higher L* value, and lower b* values for HP7 when associated to VL after the 3rd session. (p < 0.05). HP35T showed higher color change (ΔE_ab, ΔE₀₀), and lower a* value in the presence of VL (p < 0.05). ΔWI_D presented lower values for both gels, when TiO₂ was incorporated (p ≤ 0.05).

CONCLUSION

The incorporation of TiO₂ to the bleaching gel showed good stability with minimal variations in physical-chemical properties. The color change in HP35 was more effective than in HP7, but the VL boosted the bleaching effectiveness of HP7, whereas TiO₂ did not increase bleaching effectiveness.

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

OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

CLINICAL SIGNIFICANCE

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

Effects of black tea tooth staining previously to 35% hydrogen peroxide bleaching

Aim: To determine if the artificial staining with black tea (BT) influences the enamel microhardness before in-office bleaching and if BT staining is necessary to evaluate the efficacy of bleaching with 35% hydrogen peroxide Methods: Enamel/dentin blocks were randomized into groups according to the staining protocol (n=5/group): (CO) control – maintained in artificial saliva solution (AS); (BT4) immersed in black tea solution for 4 h; (BT24) immersed in black tea solution for 24 h. After the staining protocols, all specimens were kept in AS for one week, followed by bleaching (three sessions of HP application for 40 min). Knoop surface microhardness (kgF/mm2) was determined at baseline (T0), after staining (T1), after 7 days of storage in AS (T2), and after bleaching (T3). The color (ΔE00) and coordinate changes (ΔL, Δa, Δb) were measured using a digital spectrophotometer at T0 and T3. Data were submitted to one-way (ΔE00, ΔL, Δa, Δb) or two-way ANOVA repeated measures (kgF/mm2) and Tukey’s test (a=5%). Results: The staining protocols (BT4 and BT24) promoted significantly lower microhardness (T1 and T2, p<0.05) than CO, whereas CO was the only group to maintain microhardness values over time. Bleaching promoted perceptible ΔE00 without a significant difference among the groups regardless of the staining protocol (p=0.122). CO and BT4 showed no differences in terms of ΔL and Δa (p>0.05), but BT4 displayed a higher Δb than CO. Conclusion: The artificial staining with BT negatively affected the enamel surface microhardness and was not essential to evaluate the efficacy of 35% hydrogen peroxide bleaching.

Effect of conventional and power office bleaching with diode laser and led light on enamel microhardness

Aim: The present study aimed to asses enamel microhardness after office bleaching with diode laser and LED light compared to the conventional bleaching procedure. Methods: Thirty-nine human premolar teeth were collected and randomly divided into three groups regarding of the bleaching technique. Group 1: Snow O bleaching gel with LED light-curing unit; Group 2: Snow L bleaching gel with diode laser irradiation; and Group 3: Opalescence Boost bleaching gel with no light source in group 3. Enamel surface changes were evaluated in one tooth in each study group and one intact tooth as a reference under a scanning electron microscope (SEM). In the remaining samples (n=12), enamel microhardness was determined by Vickers microhardness test before and after bleaching. Data were analyzed with repeated-measures ANOVA to compare microhardness changes, followed by post hoc Tukey tests at the 0.05 significance level. Results: Enamel microhardness decreased in all the groups after bleaching, with the maximum decrease in microhardness in the Snow O bleaching group with LED light, which was significantly higher than the other groups (P=0.002). The two other groups did not exhibit any significant difference in microhardness decrease (P>0.05). Conclusion: Based on the limitations of this study, it can be concluded power bleaching with 980nm diode laser was less time-consuming compare to conventional bleaching procedure and yielded better outcomes in terms of enamel surface microhardness compared to the use of an LED light-curing unit.  

Manganese oxide increases bleaching efficacy and reduces the cytotoxicity of a 10% hydrogen peroxide bleaching gel

OBJECTIVE

The study aims to assess the effects of a 10% H₂O₂ bleaching gel with different MnO₂ concentrations on the bleaching efficacy (BE), degradation kinetics (DK) of H₂O₂, and trans-amelodentinal cytotoxicity (TC).

MATERIALS AND METHODS

Standardized bovine enamel/dentin disks (n = 96) were placed in artificial pulp chambers, and the bleaching gels were applied for 45 min. Thus, the following groups were established: (G1) no treatment (negative control/NC); (G2) 35% H₂O₂ (positive control/PC); (G3) 10% H₂O₂; (G4) 10% H₂O₂ + 2 mg/mL MnO₂; (G5) 10% H₂O₂ + 6 mg/mL MnO₂; and (G6) 10% H₂O₂ + 10 mg/mL MnO₂. After analyzing bleaching efficacy (ΔE₀₀ and ΔWI), the degradation kinetics of H₂O₂ and trans-amelodentinal cytotoxicity were determined (n = 8, ANOVA/Tukey; p < 0.05).

RESULTS

G6 presented BE (ΔE₀₀ and ΔWI) statistically similar to G2, which represented conventional in-office bleaching (p = 0.6795; p > 0.9999). A significant reduction in the diffusion of H₂O₂ occurred in G3, G4, G5, and G6 compared to G2 (p < 0.0001). The highest DK of H₂O₂ occurred in G6 (p < 0.0001), which had the lowest TC in comparison with all other bleached groups (p ≤ 0.0186).

CONCLUSION

The addition of 10 mg/mL of MnO₂ in a 10% H₂O₂ bleaching gel potentiates the degradation of this reactive molecule, which increases the BE of the product and decreases TC.

CLINICAL SIGNIFICANCE

Replacing a 35% H₂O₂ gel commonly used for conventional in-office dental bleaching by a 10% H₂O₂ gel containing 10 mg/mL of MnO₂ reduces the cytotoxicity of this professional therapy, maintaining its excellent esthetic efficacy.

Color Change after 25% Hydrogen Peroxide Bleaching with Photoactivation: A Methodological Assessment Using Spectrophotometer versus Digital Photographs

This study aimed to evaluate the color change of teeth bleached with light activation using two different objective color measurement approaches after two years of clinical follow-up. A cross-sectional retrospective clinical study according to STROBE was followed including 30 participants. The 25% hydrogen peroxide gel (Philips Zoom) was applied with a supplementary LED light for 15 min in four cycles. Tooth color was assessed based on CIEL*a*b* values using a spectrophotometer (Spectroshade) at different time points (baseline, post bleaching, 1 week, 1 year, and 2 years). Standardized digital photographs were taken at each time point. The L*, a*, and b* values were measured from the digital photographs using Adobe Photoshop software. The color difference (ΔE) was separately calculated using the L*, a*, and b* values obtained with spectrophotometric and photographic analyses at each evaluation time. Data were analyzed with non-parametric tests (p < 0.05). A color regression was detected by both measurement approaches after 1 and 2 years (p < 0.05). Greater ΔE values were acquired with the spectrophotometer compared to the digital photographic analysis (p < 0.05). Although a greater color change was observed with the spectrophotometer, both approaches were able to detect the color rebound using the 25% hydrogen peroxide light-activated in-office system. Digital photographic analysis might therefore be used to assess color change after bleaching.

Evaluation of Tooth Sensitivity of In-office Bleaching with Different Light Activation Sources: A Systematic Review and a Network Meta-analysis

OBJECTIVES

A systematic review and network meta-analysis were performed to answer the following research question: Are there differences in the risk and the intensity of tooth sensitivity (TS) among eight light activation systems for in-office bleaching in adults?

METHODS

Randomized controlled trials (RCTs) that compared at least two different in-office bleaching light activations were included. The risk of bias (RoB) was evaluated with the RoB tool version 1.0 from the Cochrane Collaboration tool. A random-effects Bayesian mixed treatment comparison (MTC) model was used independently for high- and low-concentration hydrogen peroxide. The certainty of the evidence was evaluated using the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) approach. A comprehensive search was performed in PubMed, Bridge Base Online (BBO), Latin American and Caribbean Health Sciences Literature database (LILACS), Cochrane Library, Scopus, Web of Science, and grey literature without date and language restrictions on April 23, 2017 (updated on September 26, 2019). Dissertations and theses, unpublished and ongoing trials registries, and IADR (International Association for Dental Research) abstracts (2001-2019) were also searched.

RESULTS

After title and abstract screening and the removal of duplicates, 32 studies remained. Six were considered to be at low RoB, three had high RoB, and the remaining had an unclear RoB. The MTC analysis showed no significant differences among the treatments in each network. In general, the certainty of the evidence was graded as low due to unclear RoB and imprecision.

CONCLUSION

There is no evidence that the risk and intensity of TS are affected by light activation during in-office bleaching.

Photothermal-Enhanced Fenton-like Catalytic Activity of Oxygen-Deficient Nanotitania for Efficient and Safe Tooth Whitening

The growing demand for charming smiles has led to the popularization of tooth bleaching procedures. Current tooth bleaching products with high-concentration hydrogen peroxide (HP, 30-40%) are effective but detrimental due to the increased risk of enamel destruction, tooth sensitivity, and gingival irritation. Herein, we reported a less-destructive and efficient tooth whitening strategy with a low-concentration HP, which was realized by the remarkably enhanced Fenton-like catalytic activity of oxygen-deficient TiO₂ (TiO_2-x). TiO_2-x nanoparticles were synthesized with a modified solid-state chemical reduction approach with NaBH₄. The Fenton-like activity of TiO_2-x was optimized by manipulating oxygen vacancy (OV) concentration and further promoted by the near-infrared (NIR)-induced photothermal effect of TiO_2-x. The TiO_2-x sample named BT45 was chosen due to the highest methylene blue (MB) adsorption ability and Fenton-like activity among acquired samples. The photothermal property of BT45 under 808 nm NIR irradiation was verified and its enhancement on Fenton-like activity was also studied. The BT45/HP + NIR group performed significantly better in tooth whitening than the HP + NIR group on various discolored teeth (stained by Orange II, tea, or rhodamine B). Excitingly, the same tooth whitening performance as the Opalescence Boost, a tooth bleaching product containing 40% HP, was obtained by a self-produced bleaching gel based on this novel system containing 12% HP. Besides, negligible enamel destruction, safe temperature range, and good cytocompatibility of TiO_2-x nanoparticles also demonstrated the safety of this tooth bleaching strategy. This work indicated that the photothermal-enhanced Fenton-like performance of the TiO_2-x-based system is highly promising in tooth bleaching application and can also be extended to other biomedical applications.

Assessment of the aesthetic impact and quality of life of home dental bleaching in adult patients

Background

This study aimed to evaluate the impact of home bleaching with 10% carbamide peroxide on the quality of life and aesthetic perception of patients.

Material and Methods

A total of 107 patients between 18 and 38 years of age with good oral and general health and at least one anterior tooth in color A2 or darker were selected. Patients who previously underwent any type of bleaching procedures were excluded. All patients received a home bleaching treatment with 10% carbamide peroxide. Before beginning the bleaching treatment, the selected patients responded a form with the Oral Health Impact Profile short form (OHIP-14) and Oral Aesthetic Subjective Impact Scale (OASIS) questionnaire. One month after the bleaching treatment, the patients answered the same questionnaires again. The mean ΔE after bleaching was obtained for the canines and lateral and central incisors. The OHIP-14 and OASIS data were measured for the total sample before and after bleaching using the Wilcoxon signed-rank test with a 5% significance level.

Results

The effectiveness of whitening by significant color variation was observed in all groups of teeth with less variation in ΔE for central incisors. Comparing before and after bleaching, there was no significant difference in impact for any of the seven domains and total OHIP-14 scores, although a decrease was observed in the discomfort and psychological disability domains. As for the self-perception of dental aesthetics, measured by the OASIS, there was also no significant difference for all the items evaluated; however, it was possible to observe an increase in “concern with dental appearance” after bleaching.

Conclusions

Home bleaching with 10% carbamide peroxide did not have a significant impact on patients’ quality of life and aesthetic perception, although there was a decrease in the domain of psychological discomfort and an increase in concerns about dental appearance.

Key words:Tooth Bleaching, quality of life, self-perception, dental aesthetics.

In vitro efficacy of commercial and experimental proteolytic enzyme-based whitening dentifrices on enamel whitening and superficial roughness

OBJECTIVE

To evaluate the whiteness index (W_ID ) and surface roughness (Ra) of bovine enamel after simulated tooth brushing with different commercial and experimental whitening dentifrices.

MATERIALS AND METHODS

Cylindrical enamel bovine specimens were acid etched, stained, and divided in nine groups (n = 8): Colgate® Optic White®, Crest® Baking Soda and Peroxide, Arm and Hammer® Advanced White™ Extreme Whitening, Rembrandt® Deeply White® + Peroxide, Close up® White Attraction Natural Glow, Hinode Prowhite, and experimental dentifrice containing papain (PP), bromelain (PB), or papain and bromelain (PPB). Ra and W_ID were obtained initially and after 600, 1200, and 3,600 cycles of simulated tooth brushing. Data were analyzed using two-way analysis of variance test (α = 0.05).

RESULTS

Ra was significantly influenced by both dentifrice (p = 0.043) and period of tooth-brushing simulation (p < 0.001). Except for PP and PPB, all groups showed a statistically significant increase in Ra after simulated tooth brushing. After staining and brushing, none of the materials tested increased the initial W_ID .

CONCLUSIONS

The effect of commercial whitening dentifrices may be related to their high abrasiveness. Experimental formulations tested provided a similar effect without undesired wear of enamel. Whitening dentifrices only act through an abrasive effect rather than bleaching the tooth structures. When used, special care must be taken for avoid undesired wear of enamel. Experimental dentifrices provided similar removal of extrinsic stains without undesired abrasiveness; however, this effect may be due to the use of less aggressive abrasives in their formulations.

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

OBJECTIVE

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

METHOD

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

RESULTS

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

CONCLUSION

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

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

OBJECTIVE

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

DATA

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

SOURCES

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

STUDY SELECTION

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

CONCLUSIONS

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

CLINICAL SIGNIFICANCE

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