Effect of Prior Application of Desensitizing Agent on the Teeth Submitted to In-Office Bleaching

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.

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.

Effects of the application of sodium ascorbate after in-office bleaching on the penetration of hydrogen peroxide, color change, and microtensile bond strength

This study aimed to evaluate the effects of the application of 10% sodium ascorbate (SA) after in-office bleaching on the penetration of hydrogen peroxide (HP) into the pulp chamber, color change, and microtensile bond strength (µTBS) to the resin-enamel interface. Thirty premolars and thirty molars were randomly divided into three groups (n = 20 each). One group was exposed to deionized water (negative control). The other two groups were bleached with 35% HP in a single session for 3x15 minutes for each application. However, in only one of them, SA was applied for 10 minutes after bleaching. After, the concentration (µg/mL) of HP in each pulp chamber was evaluated by UV-Vis spectrophotometry. Color changes (ΔEab, ΔE00, and ΔWID) were evaluated with a digital spectrophotometer before and in the first week after bleaching. After treatment, molars were restored and sectioned to obtain resin-enamel interface sticks for µTBS at a crosshead speed of 1 mm/min until failure. The HP concentration and µTBS data were analyzed using one-way ANOVA and Tukey tests, and color changes were analyzed by t-tests (α = 0.05). SA application significantly improved the µTBS values and reduced the HP concentrations within the pulp chambers (p < 0.0001). The application of SA significantly interfered with the color changes after bleaching when compared to the control group (p < 0.05). Application of 10% SA after in-office bleaching successfully reduced the penetration of HP into the pulp chamber; however, it decreased color change.

Can different agents reduce the damage caused by bleaching gel to pulp tissue? A systematic review of basic research

Objectives

This study aimed to investigate the effectiveness of different topical/systemic agents in reducing the damage caused by bleaching gel to pulp tissue or cells.

Materials and Methods

Electronic searches were performed in July 2023. In vivo and in vitro studies evaluating the effects of different topical or systemic agents on pulp inflammation or cytotoxicity after exposure to bleaching agents were included. The risk of bias was assessed.

Results

Out of 1,112 articles, 27 were included. Nine animal studies evaluated remineralizing/anti-inflammatories agents in rat molars subjected to bleaching with 35%-38% hydrogen peroxide (HP). Five of these studies demonstrated a significant reduction in inflammation caused by HP when combined with bioglass or MI Paste Plus (GC America), or following KF-desensitizing or Otosporin treatment (n = 3). However, orally administered drugs did not reduce pulp inflammation (n = 4). Cytotoxicity (n = 17) was primarily assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on human dental pulp cells and mouse dental papilla Cell-23 cells. Certain substances, including sodium ascorbate, butein, manganese chloride, and peroxidase, were found to reduce cytotoxicity, particularly when applied prior to bleaching. The risk of bias was high in animal studies and low in laboratory studies.

Conclusions

Few in vivo studies have evaluated agents to reduce the damage caused by bleaching gel to pulp tissue. Within the limitations of these studies, it was found that topical agents were effective in reducing pulp inflammation in animals and cytotoxicity. Further analyses with human pulp are required to substantiate these findings.

Trial Registration

PROSPERO Identifier: CRD42022337192.

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

OBJECTIVE

This in vitro study aims to evaluate of hydrogen peroxide (HP) diffusion into the pulp chamber, bleaching efficacy (BE), and pH stability (pH) of single-application high concentrated in-office bleaching gels.

MATERIALS AND METHODS

Eighty-eight healthy premolars were randomly into eleven groups (n = 8) according to the in-office dental bleaching: DSP White Clinic 35% calcium (DW), Nano White 35% (NW), Opalescence XTra Boost 40% (OB), Pola Office + 37.5% (PO), Potenza Bianco Pro SS 38% (PB), Total Blanc 35% (TB), Total Blanc One-Step 35% (TO), Whiteness Automixx 35% (WA), Whiteness Automixx Plus 35% (WP), and Whiteness HP Blue 35% (WB). A group not exposed to bleaching agents was the control group (CG). All bleaching agents were applied in one session with a single application. After the bleaching procedure, the concentration of HP diffusion (μg/mL) into the pulp chamber was assessed using UV-Vis spectrophotometry. The BE (ΔEab and ΔE00) was evaluated before and 1 week after the bleaching procedure using a digital spectrophotometer. The pH of each bleaching gel was evaluated by digital pHmeter. The one-way ANOVA and Tukey's was used for a statistical analysis (α = 0.05).

RESULTS

The concentration of HP diffusion into the pulp chamber was higher in all in-office bleaching gels when compared to CG (p < 0.0000001). However, there are a significant difference between them (p = 0.0001). A significant BE was observed in all in-office bleaching gels (p < 0.0001 for ΔEab and ΔE00), with a significant difference between them (p < 0.0001). PO, OB, TB, WP, and WB showed a higher BE when compared to DW, PB, and WA (p < 0.0001). Most bleaching gels were slightly acidic or alkaline during the total application time, while DW, PB, TB, and WA showed a high acidic behavior after 30 min of application.

CONCLUSIONS

A single application was able to produce a bleaching efficacy. However, usually, gels with slightly acidic or alkaline pH during the application time reduces the HP diffusion into the pulp chamber.

CLINICAL RELEVANCE

The single-application of bleaching gels with slightly acidic or alkaline and stable pH decreased the penetration of hydrogen peroxide into the pulp chamber in in-office bleaching and maintained the bleaching efficacy.

Use of calcium-containing bioactive desensitizers in dental bleaching: A systematic review and meta-analysis

BACKGROUND

Topical application of calcium-containing bioactive desensitizers (CBs) has been used to minimize bleaching-induced tooth sensitivity (TS). This study answered the research question "Is the risk of TS lower when CBs are used with dental bleaching in adults compared with bleaching without desensitizers?"

TYPES OF STUDIES REVIEWED

The authors included randomized clinical trials comparing topical CB application with a placebo or no intervention during bleaching. Searches for eligible articles were performed in MEDLINE via PubMed, Cochrane Library, Brazilian Library in Dentistry, Latin American and Caribbean Health Sciences Literature, Scopus, Web of Science, Embase, and gray literature without language and date restrictions and updated in September 2022. The risk of bias was evaluated using Risk of Bias Version 2.0. The authors conducted meta-analyses with the random-effects model. The authors assessed heterogeneity with the Cochrane Q test, I² statistics, and prediction interval. The authors used the Grading of Recommendations Assessment, Development and Evaluation approach to assess the certainty of the evidence.

RESULTS

After database screening, 22 studies remained, with most at high risk of bias. No difference in the risk of TS was detected (risk ratio, 0.95; 95% CI, 0.90 to 1.01; P = .08, low certainty). In a visual analog scale, the intensity of TS (mean difference, -0.98; 95% CI, -1.36 to -0.60; P < .0001, very low certainty) was lower for the CB group. The color change was unaffected (P > .08).

PRACTICAL IMPLICATIONS

Although topical CB dental bleaching did not reduce the risk of TS and color change, these agents slightly reduced the TS intensity, but the certainty of the evidence is very low.

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.

The combined use of systemic analgesic/anti-inflammatory drugs and a bioactive topical desensitizer for reduced in-office bleaching sensitivity without jeopardizing the hydrogen peroxide efficacy: a randomized, triple blinded, split-mouth clinical trial

OBJECTIVE

To evaluate the effect of combined systemic administration of paracetamol 500 mg/codeine phosphate 30 mg (PACO) and postoperative topical application of a bioactive desensitizer on in-office bleaching sensitivity and tooth color change.

MATERIALS AND METHODS

A randomized, triple-blind, split-mouth clinical trial was conducted. Forty volunteers ingested PACO (n = 20) or placebo (PLA) (n = 20). Their left/right hemiarches received topical application of a bioactive desensitizer [Nano-P™(NP)] and prophylactic paste (PAS), generating four treatment approaches: PACO/NP, PACO/PAS, PLA/NP, and PLA/PAS. Two bleaching sessions (35% hydrogen peroxide) were performed, and the PAS/NP were applied after the procedure. Sensitivity was obtained since the first bleaching session up to 7 days post-bleaching. The color change was evaluated using CIEDE2000 and whiteness index parameters up to 7 days post-bleaching. Data were analyzed using one- and two-way ANOVA/Tukey post hoc tests (p < 0.05).

RESULTS

The PLA/PAS showed a sensitivity average of at least two times higher than the PACO/NP. The treatment approaches promoted statistically similar bleaching patterns (p > 0.05).

CONCLUSION

The combined approach of systemic administration of PACO and postoperative topical application of NP reduced the level of in-office bleaching sensitivity without jeopardizing hydrogen peroxide efficacy.

CLINICAL RELEVANCE

Professionals can adopt the combined approach of systemic administration of analgesic/anti-inflammatory drugs and topical application of a bioactive desensitizer for decreased bleaching sensitivity caused by 35% hydrogen peroxide in-office.