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

Synthesis and characterization of different nano-hydroxyapatites and their impact on dental enamel following topical application for dental bleaching

OBJECTIVE

This study aims to synthesize, characterize, and assess the penetration of hydrogen peroxide (HP), color change (CC), and surface morphology changes after the application of two distinct nano-hydroxyapatite (nano-HAp).

METHODS

Two nano-HAp were previously synthesized by co-precipitation: one with rod-shaped particles (RS) and the other with spherical-shaped particles (SS). The surface charge of the nano-HAp particles was determined at varying pH levels and characterized by X-ray diffraction patterns and Fourier transform infrared spectroscopy. The morphology of the samples was assessed using scanning electron microscopy (SEM). The nano-HAp particles were applied before the dental bleaching procedure. Forty teeth were divided into four groups (n = 10) according to the bleaching treatment: no treatment, bleaching with 35 % HP only, RS application and bleaching with 35 % HP, and SS application and bleaching with 35 % HP. HP concentration (µg mL-1) was measured using UV-Vis, while CC was evaluated with a digital spectrophotometer (ΔEab, ΔE00 and WID). Additionally, four teeth from each group were selected for SEM analysis. Statistical analysis encompassed one-way ANOVA, Tukey's, and Dunnet's tests.

RESULTS

RS and SS were successfully synthesized by coprecipitation, primarily differing in pH during synthesis. Both variations of nano-HAp morphology significantly reduced HP diffusion into the pulp chamber (p < 0.001). Regarding enamel morphology, groups analyzed post dental bleaching exhibited greater HAp deposition on the enamel surface. Notably, this deposition did not impede CC.

SIGNIFICANCE

The utilization of different nano-HAp morphologies prior to dental bleaching appears to be a promising strategy for mitigating adverse effects associated with dental bleaching procedures.

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.

Effect of a brush tip on in-office bleaching gels in an attachable syringe: Hydrogen peroxide penetration, bleaching efficacy and amount of gel expended

OBJECTIVE

Evaluate the penetration of hydrogen peroxide (HP) into the pulp chamber, bleaching efficacy (BE) and amount of gel expended during in-office bleaching using an applicator brush tip and conventional tip from different commercial brands.

MATERIALS AND METHODS

104 human premolars were randomly distributed into thirteen groups (n = 8) according to the commercial brand: DSP White Clinic 35 % Calcium (DW), Nano White 35 % (NW), Total Blanc One-Step 35 % (TS), Whiteness HP Blue 35 % (WB), Potenza Bianco Pro SS 38 % (PB), Opalescence XTra Boost 40 % (OB), no bleaching (negative control), and application method: applicator brush tip and conventional tip for all groups. Initial HP concentration (%) was determined via titration and pH was measured with digital pH meter. Concentration (µg/mL) of HP into the pulp chamber was measured using UV-Vis spectrophotometry, the BE (ΔE*ab, ΔE00 and ΔWID) was evaluated with a digital spectrophotometer, and the amount of gel expended was evaluated using a precision analytical digital balance. Statistical analysis included two-way ANOVA, Tukey's, and Dunnett's test. Comparison between HP into the pulp chamber vs BE was performed with Person's correlation (α = 0.05).

RESULTS

Brush tip demonstrated a low amount of HP in the pulp chamber compared to the conventional method for all bleaching gels (p < 0.0003), as well as lower amount of gel expended (p < 0.002). The brush tip did not result in a significant difference in BE compared to the conventional (p > 0.05). No correlations were found between both factors (p > 0.05).

CONCLUSION

Brush tip showed lower penetration of HP in the pulp chamber and a reduced volume of spent gel when compared to the conventional tip, for all commercial brands.

CLINICAL RELEVANCE

Brush tip is recommended for bleaching gels in an attachable syringe due to its ability to reduce the penetration of HP into the pulp chamber and minimize the amount of bleaching gel used.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

CLINICAL SIGNIFICANCE

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

Assessment of the effect of experimental gel of pregabalin associated with 35% hydrogen peroxide bleaching on bovine dental enamel: an in vitro study

To assess the effect of bleaching with gel of pregabalin associated with 35% hydrogen peroxide on the mechanical and chemical properties and ultramorphology of dental enamel. Thirty-six (36) specimens of bovine dental incisors were obtained and divided into three groups (n = 12), namely: CG = bleaching with 35% hydrogen peroxide; KFG = bleaching with 5% potassium nitrate and 2% sodium fluoride gel + 35% hydrogen peroxide; and PGG = bleaching with experimental gel of pregabalin + 35% hydrogen peroxide. The specimens were assessed with respect to Knoop microhardness, surface roughness, and colour change, before and after bleaching. They were also assessed using scanning electron microscopy and energy-dispersive spectroscopy after treatments. All groups exhibited an increase in surface roughness and a reduction in Knoop microhardness after the protocols. There was colour change in all groups, with no difference between them. In addition, there were changes in enamel morphology and non-significant loss of calcium and phosphorus. The experimental gel of pregabalin did not influence the action of 35% hydrogen peroxide, yielding results similar to those of the other groups assessed in all the parameters. Therefore, the gel of pregabalin can be an alternative for topical application on the surfaces of the teeth in association with bleaching treatments.

The decomposition rate and bleaching efficacy of in-office bleaching gels with different pHs: a randomized controlled trial

BACKGROUND

To evaluate the decomposition rate of active hydrogen peroxide (HP) and bleaching efficacy during in-office bleaching using high-concentration HP gels with different pHs.

METHOD

A randomized, parallel, double-blind controlled trial was conducted with 40 volunteers randomized into four groups (pH 5.4; pH 7.0; pH 7.7, and pH 8.0). During the first session in-office bleaching, approximately 0.01 g of the gel was collected and titrated with potassium permanganate to obtain the concentration of active HP and pH values were measured using an electrode. Bleaching efficacy was assessed using a spectrophotometer [∆Eab, ∆E00, and WID], Vita Classical and Vita Bleachedguide scales [∆SGU]. The decomposition rate of HP concentration and pH values change were calculated using ANOVA one-way. The bleaching efficacy was assessed using two-way repeated measures ANOVA. Tukey's test was applied as a post-hoc test (p < 0.05).

RESULTS

All gels experienced decreasing HP concentration over time. pH 5.4 gel showed greatest reduction after 50 min (p < 0.001). pH 8.0 and 7.7 gels remained stable; pH 5.4 remained acidic, while pH 7.0 turned acidic (p < 0.001). No significant difference in bleaching degree was observed among gels. They all showed a similar and clinically important color change after two clinical sessions, remained stable 1-month post-treatment (p > 0.05).

CONCLUSIONS

All bleaching gels kept at least 70% of their HP content after 50 min, suggesting that there is a surplus of HP. They provided similar whitening efficacy 1-month after bleaching.

PRACTICAL IMPLICATIONS

It is possible that lower HP concentrations may be equally effective in achieving desired results while reducing the potential for side effects.

CLINICAL TRIAL REGISTRY NAME

RBR-35q7s3v.

Whitening toothpastes with hydrogen peroxide concentrations vs. at-home bleaching

OBJECTIVES

To evaluate the effect of whitening toothpastes with different hydrogen peroxide (HP) concentrations on HP permeability, color change, and physicochemical properties, compared to at-home bleaching treatment.

MATERIALS AND METHODS

Forty-nine premolars were randomized into seven groups (n = 7): untreated (control); at-home bleaching with 10% carbamide peroxide gel (AH; 10% CP) with 14 and 28 applications of 180 min each (AH [14 × 180 min] and AH [28 × 180 min]); three whitening toothpastes (3% HP; 4% HP and 5% HP) and 10% CP brushed 28 times for 90 s each (TB [28 × 90 s]). HP permeability was measured using a UV-VIS spectrophotometer and color change by a digital spectrophotometer (ΔEab, ΔE00, and ΔWID). Initial concentration, pH, and viscosity were measured through titration, digital pH meter, and rheometer, respectively. Statistical analysis included one-way ANOVA, Tukey's test, and Dunnett's test (α = 0.05).

RESULTS

4% HP group showed acidic pH, the lowest viscosity and the highest HP concentration into the pulp chamber (p < 0.05). The 10% CP groups had lower HP in the pulp chamber and greater color change than other groups (p < 0.05), except the 5% HP group in ΔEab and ΔE00. For ΔWID, the 10% CP AH groups showed greater whitening than other groups (p < 0.05).

CONCLUSIONS

Whitening toothpaste with up to 5% HP resulted in higher HP permeability and less color change compared to 10% CP. Higher HP commercial concentrations in toothpaste increased whitening effect; however, acidic pH toothpastes exhibited greater HP permeability.

CLINICAL RELEVANCE

Whitening toothpastes with high hydrogen peroxide concentrations were less effective than at-home bleaching, resulting in less color change and greater permeability of hydrogen peroxide, potentially increasing the risk of tooth sensitivity.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

CLINICAL SIGNIFICANCE

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

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

CLINICAL RELEVANCE

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

Effect of whitening toothpastes with different hydrogen peroxide concentrations: Penetration into the pulp chamber and color change

OBJECTIVES

This study evaluated the efficacy of simulated brushing with toothpastes containing different concentrations of hydrogen peroxide (HP) in pulp chamber penetration and color change. Also, physical-chemical properties (concentration, pH and viscosity) were evaluated.

METHODS

Forty-nine premolars were divided into seven groups (n = 7): untreated (control); whitening gel (White Class 6 %, 6 %BG) with one 90  min application (6 %BG 90  min) and 14 applications of 90  min (6 %BG 14×90 min); toothpastes (Colgate Luminous White Glow 3 %, 3 %TP; Crest 3D White Brilliance 4 %, 4 %TP; Colgate Optic White Pro-Series 5 %, 5 %TP) and 6 %BG toothbrushing for 14 applications of 90 s. HP penetration into the pulp chamber was measured through UV-Vis spectrophotometry and color change with a spectrophotometer (ΔEab, ΔE00, and ΔWID). Initial concentration, pH, and viscosity were measured through Titration, Digital pH-meter, and Rheometer, respectively. Statistical analysis used one-way ANOVA and Tukey's test (α = 0.05).

RESULTS

6 %BG (14×90 min) and 4 %TP groups showed acidic pH and higher concentrations of HP in the pulp chamber compared to the other groups (p < 0.05). On the other side, 3 %TP and 5 %TP groups showed alkaline pH, higher viscosity between the toothpastes and lower HP penetration (p < 0.05). The 6 %BG AH (14×90 min) group exhibited the most significant color change (ΔEab, ΔE00, and ΔWID) (p < 0.05).

CONCLUSIONS

Brushing with whitening toothpaste with an acidic pH leads to greater HP penetration into pulp chamber; but, even when a high concentrated HP whitening toothpaste was used, a lower whitening effect was observed when compared to a two-week at-home bleaching.

CLINICAL SIGNIFICANCE

Whitening toothpastes containing up to 5 % HP produced lower whitening effect than two-week at-home bleaching. Additionally, HP was detected within the pulp chamber which can potentially impact in tooth sensitivity.

At-home bleaching with carbamide peroxide with concentrations below 10%: bleaching efficacy and permeability in the pulp chamber

OBJECTIVES

To evaluate the bleaching efficacy and permeability of hydrogen peroxide (HP) in the pulp chamber of human teeth bleached with lower concentrations of carbamide peroxide gel (4%, 5% and 7% CP).

MATERIALS AND METHODS

Bleaching gels with lower concentrations were formulated and a commercial standard gel, 10% CP, was used as a reference. Fifty-six human premolars were randomly divided into four groups. Applications of the bleaching gel were made for 3 h for 21 days. The bleaching efficacy was evaluated by digital spectrophotometry on 1, 7, 14 and 21 days, with analysis in the ∆Eab, ∆E00 and WID color spaces. The concentration of HP in the pulp chamber was measured in the same periods by UV-Vis spectrophotometry (µg/mL). Two-way repeated analysis of variance (ANOVA) examined bleaching efficacy and HP permeability, followed by Tukey's post-hoc test (α = 0.05).

RESULTS

All groups showed significant color changes, with no statistical differences after the second and third week of bleaching (p > 0.05). The 'time' factor was statistically different (p < 0.05), increasing the bleaching efficacy throughout the treatment. The 4% CP group had lower HP levels in the pulp chamber (p < 0.05).

CONCLUSIONS

The results seem promising, revealing that low concentration gels are as effective as 10% CP with the benefit of reducing the amount of HP in the pulp chamber.

CLINICAL RELEVANCE

Low concentration 4% PC and 5% PC maintains bleaching efficacy, reduces the penetration of HP peroxide into the pulp chamber, and may reduce tooth sensitivity.

Evaluation of hydrogen peroxide permeability, color change, and physical-chemical properties on the in-office dental bleaching with different mixing tip

OBJECTIVE

This study aims to assess hydrogen peroxide (HP) penetration into the pulp chamber, color change (CC), physical-chemical properties, and material wastage (MW) and material used (MU) in mixing tips when using in-office bleaching gels with two different mixing tips.

MATERIALS AND METHODS

Forty teeth were divided into five groups (n = 8) based on the bleaching gels used (Pola Office +37.5% [PO+] and Whiteness HP Automixx Plus 35% [AM+]) and the mixing tip types (T-Mixer and Helical). A negative control group was treated with ultra-purified water. HP concentration was measured using UV-Vis, and CC was evaluated with a digital spectrophotometer. Initial concentration, pH, and viscosity were measured through Titration, a Digital pH meter, and Rheometer, respectively. MW and MU were measured using a precise analytical balance. Statistical analysis included two-way ANOVA, Tukey's, and Dunnett's test (α = 0.05).

RESULTS

A higher HP concentration was observed with PO+ with the Helical mixing tip in comparison with AM+ (p = 0.01). No significant differences in CC or MU were found for different mixing tips (p = 0.001). The T-mixer mixing tip resulted in significantly less MW (p < 0.00001) and improved mixture homogeneity and viscosity.

CONCLUSIONS

Utilizing a T-mixer with self-mixing bleaching gels achieves comparable CC while reducing MW. Moreover, it decreases HP penetration when using PO+.

CLINICAL SIGNIFICANCE

For the application of a self-mixing in-office bleaching gel, a T-mixer mixing tip should be recommended, as it reduces the penetration of hydrogen peroxide into the pulp chamber when using PO+, while also minimizing gel wastage.

Low and high hydrogen peroxide concentrations of in-office dental bleaching associated with violet light: an in vitro study

OBJECTIVES

This study aims to assess hydrogen peroxide (HP) penetration within the pulp chamber, color change (CC), physical-chemical properties, and temperature using in-office different concentration bleaching gels with or without violet light.

MATERIALS AND METHODS

Fifty teeth were divided into five groups (n = 10) based on the HP concentration bleaching gels used (6% and 35%) and the used violet light (with or without). HP penetration within the pulp chamber was measured using UV-Vis. The CC was evaluated with a digital spectrophotometer. Initial and final concentration, and pH were measured through titration, and a Digital pHmeter, respectively. Temperature analyses were measured through a thermocouple. Statistical analysis included two-way ANOVA, Tukey's, and Dunnett's test (α = 0.05).

RESULTS

The presence of violet light did not affect the amount of HP within the pulp chamber, or the CC (p > 0.05). Greater penetration of HP was observed within the pulp chamber, as well as CC when using 35% HP (p < 0.05). The final concentration of both gels was lower than the initial concentration, regardless of the use of violet light (p < 0.05). The initial and final pH levels remained neutral and stable (p > 0.05). The pulp temperature increased when the gels were used in conjunction with violet light (p < 0.05).

CONCLUSIONS

Using violet light in conjunction with 6% or 35% HP does not alter the physical properties of the bleaching agents, the penetration of HP or enhance color change. However, an increase in temperature was observed when violet light was applied associated with bleaching gels.

CLINICAL RELEVANCE

While the simultaneous use of violet light with hydrogen peroxide 6% or 35% does not alter the material's properties, it also does not bring benefits in reducing hydrogen peroxide penetration and improving color change. Furthermore, the use of violet light increases pulp temperature.

In vitro evaluation of the effect of different bleaching varnishes: Hydrogen peroxide penetration into the pulp chamber and color change

OBJECTIVE

To evaluate the penetration of hydrogen peroxide (HP) into the pulp chamber and the color change of different bleaching varnishes in low concentrations used for at-home bleaching.

MATERIALS AND METHODS

Ninety healthy premolars were used, randomly distributed into nine groups (n = 10) according to bleaching varnish (PL, PolaLuminate; VS, VivaStyle Paint On Plus; CA, Cavex Bite&White whitening pen and; AW AlignerWhite) and time (10 and 30 min), and a control group (no bleaching). The penetration of HP was evaluated by UV-Vis spectroscopy. To evaluate the color change (ΔEab , ΔE00 , ΔWID ) a digital spectrophotometer was used (α = 0.05).

RESULTS

The AW group in 10 min and the control group showed similar and lower HP penetration in the pulp chamber when compared to the other groups (p = 0.003). Increasing the application time to 30 minutes elevated the amount of HP inside the pulp chamber for all groups (p = 0.003), except for PL (p > 0.05). When applied for 30 min all bleaching varnishes showed higher color change (ΔWID ) when compared to 10 min (p = 0.04).

CONCLUSIONS

For all bleaching varnishes evaluated, PolaLuminate applied for 30 min showed lower penetration into the pulp chamber and higher bleaching effects.

CLINICAL SIGNIFICANCE

The use of bleaching varnishes seems promising for teeth bleaching, but it varies according to user product and protocol.

Evaluation of at-home bleaching protocol with application on different surfaces: bleaching efficacy and hydrogen peroxide permeability

Objectives

This study aimed to evaluate the bleaching efficacy and hydrogen peroxide permeability in the pulp chamber by the at-home bleaching gel in protocols applied on different dental surfaces.

Materials and Methods

Forty premolars were randomly into 4 groups: control group no bleaching, only application on the buccal surface (OB), only application on the lingual surface (OL) and application in buccal and lingual surfaces, simultaneously (BL). At-home bleaching gel (White Class 7.5%) was used for the procedure. The bleaching efficacy was evaluated with a digital spectrophotometer (color change in CIELAB [ΔE ab] and CIEDE 2000 [ΔE 00] systems and Whitening Index for Dentistry [ΔWID]). The hydrogen peroxide permeability in the pulp chamber (µg/mL) was assessed using UV-Vis spectrophotometry and data were analyzed for a 1-way analysis of variance and Tukey's test (α = 0.05).

Results

All groups submitted to bleaching procedure showed bleaching efficacy when measured with ΔE ab and ΔE 00 (p > 0.05). Therefore, when analyzed by ΔWID, a higher bleaching efficacy were observed for the application on the groups OB and BL (p = 0.00003). Similar hydrogen peroxide permeability was found in the pulp chambers of the teeth undergoing different protocols (p > 0.05).

Conclusions

The application of bleaching gel exclusively on the OB is sufficient to achieve bleaching efficacy, when compared to BL. Although the OL protocol demonstrated lower bleaching efficacy based on the ΔWID values, it may still be of interest and relevant in certain clinical scenarios based on individual needs, requiring clinical trials to better understand its specificities.

Hydrogen Peroxide Diffusion through Dental Tissues-In Vitro Study

Whitening products commonly utilize hydrogen peroxide (HP) as an active principle, which can penetrate dental tissues with potential side effects due to its low molecular weight. This study aimed to evaluate the HP diffusion of two in-office whitening products, namely 6% VivaStyle Paint On Plus (VS) and Opalescence Boost 40% (OP), in different tooth types. Additionally, the influence of the area of exposure, dental tissue thickness and pulp chamber volume was assessed. Each group consisted of eighteen intact anterior (A), premolar (PM) and molar (M) human teeth, and a positive pulpal pressure model was employed. The samples were analyzed using spectrophotometry, and results were expressed as the mean and 95% confidence interval. Statistical tests and linear regression models were appropriately applied at α = 5%. The total HP (µg) retrieved was as follows: VS-A, 1.333 [1.214, 1.452]; OP-A, 1.538 [1.457, 1.620]; VS-PM, 1.208 [1.123, 1.291]; OP-PM, 3.628 [3.401, 3.855]; VS-M, 2.560 [2.297, 2.823]; and OP-M, 4.197 [3.997, 4.396], with statistically significant differences in diffusion kinetics between whitening products for PM and M. Several HP concentrations attained a minimum cytotoxicity value of 2.22 µg/mL. The regression model shows that OP exposed the pulp chamber to 1.421 µg of HP more than that of VS. Different whitening products can cause cytotoxic HP concentrations in the pulp chamber, with a higher risk observed in molars.