A clinical, randomized, controlled study on the use of desensitizing agents during tooth bleaching

Effect of air-abrasion pretreatment with three desensitizing agents on efficacy of in-office tooth bleaching

OBJECTIVE

To evaluate the influence of air-abrasion of enamel with three different desensitizing powders on the whitening effect of a bleaching gel containing 40% H2O2, which was used for in-office tooth bleaching.

MATERIALS AND METHODS

Forty human incisors, extracted and prepared, were acquired for this study and subsequently randomized into four groups (n = 10). The control group specimens underwent no pretreatment prior to the bleaching procedure, whereas the remaining three groups underwent air abrasion using distinct desensitizing powders; (a) Sylc, which contains bioglass 45S5; (b) BioMinF, which contains calcium phospho-fluoro-silicate glass; and (c) MI Pearls, which contains nano-hydroxyapatite, 1 h preceding the Opalescence Boost PF 40% bleaching procedure. Color measurements were conducted using a double-beam UV-Vis spectrophotometer at four distinct time points (prior to bleaching, 24 h, 15 days, and 30 days post-bleaching).

RESULTS

Tooth color change outcomes revealed that there were no statistically significant results with respect to the interaction of the two criteria (treatments and time) (p = 0.990). Additionally, there were no statistically significant results with respect to the main effects of treatments (p = 0.385), while there were statistically significant effects with respect to the time criterion (p = 0.013).

CONCLUSIONS

The use of the tested desensitizing powders prior the bleaching procedure did not affect the tooth color change induced by the tested bleaching agent.

CLINICAL SIGNIFICANCE

Tooth color change and whiteness are not affected by air-abrasion desensitizing treatments when applied prior to in-office bleaching procedures.

Effectiveness of desensitizing toothpastes in reducing tooth sensitivity after tooth bleaching: a systematic review

OBJECTIVE

To evaluate the effectiveness of desensitizing toothpastes in reducing post-bleaching tooth sensitivity.

MATERIALS AND METHODS

A systematic review of randomized clinical trials was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Electronic searches were conducted in the PubMed/MEDLINE, Scopus, Web of Science, The Cochrane Library and Embase databases, using the following terms: (dentifrices OR toothpaste) AND (sensitive OR sensitivity OR dental sensitivity) AND (dental bleaching OR tooth bleaching OR dental whitening OR tooth whitening).

RESULTS

Five studies involving 387 individuals undergoing in-office or at-home teeth bleaching were reviewed. Desensitizing toothpastes reduced sensitivity effectively after home bleaching with 22% carbamide peroxide and single-session in-office bleaching with 35% hydrogen peroxide. However, they were ineffective for home bleaching with 16% carbamide peroxide and in-office bleaching across two sessions with 35% or 38% hydrogen peroxide.

CONCLUSION

Desensitizing toothpastes are effective for home bleaching with high concentration carbamide peroxide and single-session in-office bleaching with highly concentrated hydrogen peroxide, but ineffective for home bleaching with low concentration carbamide peroxide and two-session in-office bleaching with concentrated hydrogen peroxide.

Evaluation of Turkish Dentists' Approach to Over-the-Counter Whitening Agents: A Questionnaire-Based Study

AIM

Over-the-counter teeth-whitening products have become popular in accordance with the increasing demands of patients. These products can also be recommended to patients by dentists. The aim was to determine the rates of recommendation of over-the-counter teeth whitening products by dentists in Turkey divided into different categories for their patients and to interpret them based on a cause-and-effect relationship.

MATERIAL AND METHODS

After obtaining ethics committee approval, the survey questions were created using Google Forms (Google Inc., Mountainview, CA) and delivered to dentists via social media. Dentists who signed the informed consent form completed the survey. Within the study's scope, statistical analyses were conducted using IBM SPSS Statistics for Windows, version 26.0 (IBM Corp., Armonk, NY). Values were expressed as frequency (n) and percentage (%). A chi-square test was used to compare participants' teeth-whitening recommendations according to their demographic characteristics. The statistical significance level was accepted as p <0.05 throughout the study.

RESULTS

A total of 57.9% of dentists working in Turkey did not recommend over-the-counter teeth-whitening products to their patients. When the answers to the question "Which whitening products sold on the market do you recommend to your patients?" were compared according to the participants' place of work, there was a statistically significant difference between the place of work and the recommended whitening product (p <0.05). Participants working in the private sector answered "I do not recommend" at a higher rate than participants working in the public sector. Among those who recommended toothpaste, more dentists with five or fewer years of experience recommended toothpaste to their patients than dentists with greater than five years of experience. Additionally, more dentists working in the public sector recommended toothpaste to their patients than dentists working in the private sector, and more specialist dentists recommended toothpaste to their patients than general practitioner dentists.

CONCLUSION

Most dentists in Turkey do not recommend over-the-counter teeth-whitening products to their patients. Among those who recommend such products, toothpaste has been determined to be the first choice. The results of this study may raise awareness among dentists about over-the-counter teeth-whitening products and encourage new studies.

Efficacy of Biosilicate Glass-ceramic and Fluoride Varnish in the Treatment of Dentin Hypersensitivity-A Randomized Controlled Clinical Trial

OBJECTIVE

The objective of this study was to compare the efficacy of Biosilicate and Duraphat in the treatment of dentin hypersensitivity (DH).

METHODS AND MATERIALS

This clinical trial was conducted with young adults presenting DH. A visual analogue scale (VAS) was used to assess the level of pain, using volatile and tactile tests. Forty participants presenting two teeth with DH were included, and these teeth were divided into two groups according to the treatment: Biosilicate or Duraphat. Each product was randomly applied on one tooth per participant once a week for 4 weeks and evaluated every 15 days for 60 days after the last application.

RESULTS

The mean and standard deviation (SD) of VAS values for the initial volatile sensitivity evaluation were 6.18 (1.99) and 6.08 (1.98) for the Biosilicate and Duraphat groups, respectively, and at the fourth week 0.48 (1.5) and 0.83 (1.58). After 60 days, the volatile sensitivity showed the following values: 0.63 (1.19) for Biosilicate and 1.03 (1.07) for Duraphat. The intragroup comparison showed a significant reduction of mean VAS values for DH-related pain assessed by volatile testing for both groups (p<0.001), and the assessment at the 60-day follow-up showed mean values statistically similar to those obtained at the end of treatment. Initial tactile sensitivity observed was 1.48 (2.39) for the Biosilicate and 1.4 (2.2) for the Duraphat group and at the 60-day follow-up 0.23 (0.73) and 0.15 (0.36), respectively, with significant statistical difference (p<0.002). When the reduction in tactile and volatile sensitivities between both groups was compared, no statistically significant difference was observed.

CONCLUSION

This study indicated that both products were able to promote an important reduction in dentin hypersensitivity with similar results within a 60-day follow-up.

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.

Effect of strontium fluorophosphate bioactive glass on color, microhardness and surface roughness of bleached enamel

BACKGROUND

Undesirable effects of tooth bleaching can alter the biomechanical properties of enamel.

OBJECTIVE

To determine the influence of strontium fluorophosphate bioactive glass (Sr-FPG) on color, microhardness and surface roughness of enamel bleached with 35% hydrogen peroxide.

METHODS

The labial enamel of 36 extracted intact human anterior teeth were divided into 3 groups (n= 12), group 1 (HP): bleaching with 35% hydrogen peroxide only, group 2 (Sr-HP): bleaching with Sr-FPG incorporated 35% hydrogen peroxide and group 3 (HP-SrFPG): bleaching with 35% hydrogen peroxide followed by remineralization with Sr-FPG. Four consecutive eight-minute applications of the bleaching gel were done twice in all the groups. Color change (ΔE), microhardness and surface roughness were evaluated at baseline, post-bleaching and post-remineralization using spectrophotometer, Vickers hardness tester and profilometric analysis respectively.

RESULTS

The mean ΔE among the groups was statistically similar (p> 0.05). Bleaching with HP significantly reduced microhardness (p< 0.05), whereas bleaching with Sr-HP and HP-SrFPG did not (p> 0.05). Post-bleaching microhardness in Sr-HP was significantly higher than HP-SrFPG (p< 0.05). An increased surface roughness was seen in Sr-HP bleached samples (p< 0.05).

CONCLUSION

The addition of Sr-FPG to hydrogen peroxide significantly improved enamel microhardness than its use post-bleaching. An increase in surface roughness was seen post-bleaching with HP and Sr-HP.

Sol-Gel Technologies to Obtain Advanced Bioceramics for Dental Therapeutics

The aim of this work is to review the application of bioceramic materials in the context of current regenerative dentistry therapies, focusing on the latest advances in the synthesis of advanced materials using the sol-gel methodology. Chemical synthesis, processing and therapeutic possibilities are discussed in a structured way, according to the three main types of ceramic materials used in regenerative dentistry: bioactive glasses and glass ceramics, calcium phosphates and calcium silicates. The morphology and chemical composition of these bioceramics play a crucial role in their biological properties and effectiveness in dental therapeutics. The goal is to understand their chemical, surface, mechanical and biological properties better and develop strategies to control their pore structure, shape, size and compositions. Over the past decades, bioceramic materials have provided excellent results in a wide variety of clinical applications related to hard tissue repair and regeneration. Characteristics, such as their similarity to the chemical composition of the mineral phase of bones and teeth, as well as the possibilities offered by the advances in nanotechnology, are driving the development of new biomimetic materials that are required in regenerative dentistry. The sol-gel technique is a method for producing synthetic bioceramics with high purity and homogeneity at the molecular scale and to control the surfaces, interfaces and porosity at the nanometric scale. The intrinsic nanoporosity of materials produced by the sol-gel technique correlates with the high specific surface area, reactivity and bioactivity of advanced bioceramics.

Improving Oral Health with Fluoride-Free Calcium-Phosphate-Based Biomimetic Toothpastes: An Update of the Clinical Evidence

As the demand for clinically effective fluoride-free oral care products for consumers increases, it is important to document which types of toothpastes have been shown in clinical studies to be effective in improving oral health. In this review, we included different indications, i.e., caries prevention, improving periodontal health, reducing dentin hypersensitivity, protecting against dental erosion, and safely improving tooth whitening in defining what constitutes improvement in oral health. While there are several professional and consumer fluoride-containing formulations fortified with calcium-phosphate-based ingredients, this review focuses on fluoride-free toothpastes containing biomimetic calcium-phosphate-based molecules as the primary active ingredients. Several databases were searched, and only clinical trials in human subjects were included; in vitro and animal studies were excluded. There were 62 oral health clinical trials on biomimetic hydroxyapatite (HAP), 57 on casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), 26 on calcium sodium phosphosilicate (CSPS, or so called Bioglass), and 2 on β-tricalcium phosphate (β-TCP). HAP formulations were tested the most in clinical trials for benefits in preventing caries, dentin hypersensitivity, improving periodontal health, and tooth whitening. Based on the current clinical evidence to date, fluoride-free HAP toothpaste formulations are the most versatile of the calcium phosphate active ingredients in toothpastes for improving oral health.

In Vitro Evaluation of Tooth-Whitening Potential of Peroxide-Free OTC Dental Bleaching Agents

Purpose: To evaluate and compare the tooth-whitening potential of five over-the-counter (OTC), peroxide-free dental bleaching methods as well as an experimental tooth-whitening solution containing 0.1% hydrogen peroxide complexed with doping agents with a gold standard (positive control) containing 16% carbamide peroxide. Material and Methods: Eighty permanent bovine incisor teeth were randomly allocated to eight different groups. Two teeth from each group were immerged into five staining solutions represented by coffee, tea, red wine, and curry mixed in warm oil or distilled water (control group) and stored at 37 °C for 28 days in an incubator. The teeth were then reallocated to the eight groups, resulting in ten samples per group, and each group was matched with a bleaching product. The bleaching procedures were executed following the manufacturer’s recommendations. The color of each sample was assessed over a white and black background using a quantitative numerical measurement approach with a calibrated spectrophotometer. Spectrophotometric measurements were performed after exposing the teeth to the bleaching agent for 60 min (T2), 100 min (T3), and 200 min (T4), and ΔE00 was calculated. Results: When analyzed over a white background, the mean ΔE00 values ranged from 2.14 (placebo) to 6.32 (Opalescence PF). When analyzed over a black background, the mean ΔE00 values ranged from 2.31 (placebo) to 5.78 (Opalescence PF). Statistically significant ΔE00 color changes over time for the eight groups and five staining solutions at T1 and T4 were assessed for both backgrounds using repeated ANOVA followed by Fisher’s LSD post hoc test (p-value < 0.01). Conclusions: All tested over-the-counter whitening kits except one exhibited positive color variation. However, the individual performance differed vastly from one brand to the other, and the overall performance was less effective compared to the conventional carbamide-peroxide-based positive control.

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.

Impact of silanization of different bioactive glasses in simplified adhesives on degree of conversion, dentin bonding and collagen remineralization

OBJECTIVE

To analyze simplified adhesive containing pure or silanized bioglass 45S5 (with calcium) or Sr-45S5 (strontium-substituted) fillers applied on dentin and to evaluate the microtensile bond strength (µTBS), interface nanoleakage, degree of conversion of adhesive, collagen degradation and remineralization.

METHODS

Ambar Universal adhesive (FGM) was doped with 10 wt% bioactive glasses to form following groups: Control (no bioglass), 45S5 (conventional bioglass 45S5), Sr-45S5 (Sr-substituted bioglass 45S5), Sil-45S5 (silanized bioglass 45S5) and Sil-Sr-45S5 (silanized bioglass Sr-45S5). Adhesives were applied after dentin acid-etching using phosphoric acid at extracted human molars. Resin-dentin sticks were obtained and tested for µTBS, nanoleakage at 24 h or 6 months. Degree of conversion was measured using micro-Raman spectroscopy. Dentin remineralization was assessed by FTIR after 6-month storage in PBS. Hydroxyproline (HYP) release was surveyed by UV-Vis spectroscopy. Statistical analysis was performed using ANOVA and Tukey's test (p < 0.05).

RESULTS

Regarding µTBS, Sr-45S5 and 45S5 presented higher and stable results (p > 0.05). Control (p = 0.018) and Sil-Sr-45S5 (p < 0.001) showed µTBS reduction after 6-month aging. Sil-Sr-45S5 showed higher HYP release than that obtained in the 45S5 group. Sil-45S5 showed mineral deposition and increase in µTBS (p = 0.028) after 6-months. All experimental adhesives exhibited higher degree of conversion compared to Control group, except for 45S5. All adhesives created gap-free interfaces, with very low silver impregnation, except for Sil-Sr-45S5.

SIGNIFICANCE

The incorporation of silanized 45S5 bioglass into the universal adhesive was advantageous in terms of dentin remineralization, bonding performance and adhesive polymerization. Conversely, Sil-Sr-45S5 compromised the µTBS, interface nanoleakage and had a negative impact on HYP outcomes.

Effect of bioactive glass paste on efficacy and post-operative sensitivity associated with at-home bleaching using 20% carbamide peroxide: a randomized controlled clinical trial

Background

The aim of this study was to evaluate the effect of bioactive glass (BAG) 45S5 paste on colour change and tooth sensitivity (TS) when used in combination with 20% carbamide peroxide (CP) during at-home vital tooth bleaching.

Methods

Twenty-four patients were selected and assigned into two experimental groups (n = 12) in a double-blind study design. Each patient received 20% CP followed by the application of either BAG paste or non-active placebo paste. The shade evaluation was performed using a digital spectrophotometer based on the CIE L*a*b* colour space system at different time points and the overall colour changes ΔE were calculated. TS was evaluated using visual analogue scale (VAS). The values of ΔE and TS were statistically analysed using paired t-test. The level of statistical significance was established at p = 0.05.

Results

The overall colour changes (ΔE) between baseline and each time point showed no significant differences between BAG and placebo groups (p > 0.05). The use of BAG paste significantly decreased TS reported by the participants.

Conclusions

The association of BAG paste with at-home bleaching treatment presents a promising method as it decreased TS and did not deteriorate bleaching efficacy.

Trial registration This study was approved and registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) under Registration number: ACTRN12621001334897.

Combined Bleaching Technique Versus At-home Bleaching-A Single-blind Randomized Controlled Trial

OBJECTIVE

To compare the efficacy, color stability, and tooth sensitivity (TS) of combined bleaching, using a modified protocol with at-home bleaching.

METHODS

Eighty participants were randomized into two groups. In the combined group, a desensitizing gel was applied (10 minutes) prior to in-office bleaching (35% hydrogen peroxide (H2O2), 2×15 minute applications) and at-home bleaching (4% H2O2, 2×30 minutes for 21 days) started the next day. In the at-home group, only the at-home bleaching was performed. Color was recorded at the beginning and postbleaching with two scales (VITA Classical and Bleachedguide) and Easyshade spectrophotometer. The TS was recorded daily with a 0-10 visual analogue scale (VAS) and five-point numeric rating scale (NRS).

RESULTS

A 40% lower risk (RR=1.4; 95% CI 1.1-1.9) was observed in the at-home group. Higher color change and intensity of TS [mean difference 2.3 (95% CI 1.3-3.3) in the VAS] was observed in the first week for the combined group. After the end of the protocol, a bleaching degree was detected for both groups, with no significant difference between both groups (p>0.05).

CONCLUSION

The combined group produced a slightly higher degree of color change than at-home bleaching but with a higher risk and intensity of TS.

Topical application of Otosporin® before in-office bleaching: a split mouth, triple-blind, multicenter randomized clinical trial

OBJECTIVES

To evaluate if the topical application of Otosporin® before in-office bleaching with a 35% hydrogen peroxide (HP) gel reduces the risk and intensity of tooth sensitivity (TS), as well as the bleaching effectiveness.

MATERIALS AND METHODS

Twenty participants were selected for this split mouth, triple-blind, multicenter randomized clinical trial. Before each bleaching session, the placebo was applied in the patient's hemi-arch and the other half received the Otosporin®, according to the randomization procedure. Both products were applied topically for 10 min. The 35% HP was applied in two sessions with a 1-week interval. The risk and intensity of TS were assessed using the Numerical Scale (NRS) and the Visual Analog Scale (VAS). The bleaching effectiveness were evaluated with the visual scales and with a digital spectrophotometer. The absolute risk of TS was compared by McNemar's test. To compare the intensity of TS, the Wilcoxon signed-rank test was used to evaluate the NRS, while the paired t test was used to evaluate VAS. Bleaching effectiveness (ΔSGUs and ΔE_ab, ΔE₀₀, and ΔWI_D) was compared between groups using the paired t-test (α = 0.05).

RESULTS

No significant difference at risk (p = 1.0) and intensity of TS (p > 0.59; VAS and p = 1.00 for NRS) was detected between groups. For both groups, a significant bleaching was observed after 30 days of evaluation (p < 0.39).

CONCLUSIONS

The previous application of Otosporin® in the in-office bleaching did not reduce the risk and intensity of TS and did not affect the effectiveness of the bleaching.

CLINICAL RELEVANCE

The application of Otosporin® before in-office bleaching with 35% HP was not able to reduce the risk and intensity of TS.

Direct Radiotherapy-Induced Effects on Dental Hard Tissue in Combination With Bleaching Procedure

Introduction: The aim of this study was to evaluate the effects of radiation and tooth bleaching on the physical and morphological properties of enamel and dentin on permanent teeth.

Materials and Methods: Eighty fresh, non-carious third molars were used in this study. Before cutting the crown in half, the teeth samples were randomly allocated to treatment and control groups by using a lottery method. The first group (n = 20) underwent standard radiation protocol (2 Gy/fraction/day, 5 days/week) with bleaching treatment afterward using 16% carbamide peroxide gel, the second group (n = 20) underwent standard radiation protocol with afterward bleaching treatment using 38% hydrogen peroxide, the third group (n = 20) underwent a short, one strong, experimental dose of 70 Gy with afterward bleaching treatment using 16% carbamide peroxide gel, and the fourth group (n = 20) underwent one strong, experimental dose of 70 Gy with afterward bleaching treatment using 38% hydrogen peroxide gel. Groups 5–8 (n = 20) served as control as they underwent only bleaching treatment. Vickers microhardness and surface roughness were performed before (initial) and after irradiation and before bleaching or after only bleaching. The effects of irradiation and bleaching on microhardness (or roughness) of enamel and dentin were analyzed in the repeated-measures ANOVA model.

Results: Enamel microhardness after experimental single 70-Gy irradiation or after standard radiation protocol and bleaching with 16 or 38% gel was not statistically significant from microhardness in the control group (p &gt; 0.05). There was a statistically significantly greater reduction in the average microhardness of enamel and dentin during bleaching with 38% gel compared to 16% for both radiation protocols (p &lt; 0.001). After experimental 70-Gy irradiation and bleaching, a 16% statistically significant increase in surface roughness was found for enamel (p = 0.006) and dentin (p = 0.018), while this was not recorded for 38% gel. There was a statistically significantly greater increase in the average roughness of enamel and dentin during bleaching with 38% gel compared to 16% (p &lt; 0.001) for both radiation protocols.

Conclusions: Directly induced radiation leads to potential damage of hard dental tissues, which can be further damaged by additional bleaching. If teeth whitening is necessary after irradiation, it is suggested to use lower concentrations of whitening gels.

Assessment of the effect of experimental bleaching agent with nano-bioactive material on postoperative sensitivity: A randomized, triple blind clinical trial

OBJECTIVES

This clinical study aimed to evaluate the effect of incorporating bioactive nanoparticles (n-Bm) inside an in-office bleaching gel on the risk and intensity of tooth sensitivity (TS) and on bleaching effectiveness.

MATERIALS AND METHODS

Sixty-six participants were selected and randomly assigned into two groups: control-only in-office gel and experimental-in-office gel with n-Bm. Teeth were bleached in two sessions (3 × 15-min). TS was recorded using a VAS and NRS. The color change was evaluated by subjective (VITA Classical and VITA Bleachedguide) and objective (Easyshade spectrophotometer) methods at baseline and 30 days after the end of treatment. The TS was evaluated by McNemar, Wilcoxon Signed Rank, and paired t test. The color changes between groups were compared using paired t test (α = 0.05).

RESULTS

No significant differences between the groups were observed in the risk (control = 27% [95%IC 18-39]; experimental = 21% [95%IC 13-32]) and intensity of TS, as well as in the color change (p >0.05) for any color measurement.

CONCLUSION

The inclusion of n-Bm into the bleaching agents did not affect the whitening effectiveness, as well as the risk and intensity of TS between groups. However, the results of the absolute risk of TS were low for both in-office gels used.

CLINICAL SIGNIFICANCE

Despite no significant differences between groups, both experimental bleaching agents present suitable results with low values for TS.

Analysis of permeability and biological properties of dentin treated with experimental bioactive glasses

OBJECTIVES

To evaluate obliterating capability and biological performance of desensitizing agents.

METHODS

50 dentin blocks were distributed according to the desensitizing agent used (n = 10): Control (Artificial saliva); Ultra EZ (Ultradent); Desensibilize Nano P (FGM); T5-OH Bioactive Glass (Experimental solution); F18 Bioactive Glass (Experimental solution). Desensitizing treatments were performed for 15 days. In addition, specimens were subjected to acid challenge to simulate oral environment demineralizing conditions. Samples were subjected to permeability analysis before and after desensitizing procedures and acid challenge. Cytotoxicity analysis was performed by using Alamar Blue assay and complemented by total protein quantification by Pierce Bicinchoninic Acid assay at 15 min, 24-h and 48-h time points. Scanning electron microscopy and energy dispersion X-ray spectroscopy were performed for qualitative analysis. Data of dentin permeability was analyzed by two-way repeated measures ANOVA and Tukey's test. For cytotoxicity, Kruskal-Wallis and Newman-Keuls tests.

RESULTS

for dentin permeability there was no significant difference among desensitizing agents after treatment, but control group presented highest values (0.131 ± 0.076 Lp). After acid challenge, control group maintained highest values (0.044 ± 0.014 Lp) with significant difference to other groups, except for Desensibilize Nano P (0.037 ± 0.019 Lp). For cytotoxicity, there were no significant differences among groups.

CONCLUSION

Bioglass-based desensitizers caused similar effects to commercially available products, regarding permeability and dentin biological properties.

CLINICAL SIGNIFICANCE

There is no gold standard protocol for dentin sensitivity. The study of novel desensitizing agents that can obliterate dentinal tubules in a faster-acting and long-lasting way may help meet this clinical need.

Topical application of a desensitizing agent containing potassium nitrate before dental bleaching: a systematic review and meta-analysis

OBJECTIVES

To conduct a systematic review and meta-analysis to evaluate the risk and intensity of tooth sensitivity (TS) after topical application of desensitizers containing potassium nitrate before dental bleaching.

METHODS

We searched PubMed, Scopus, Web of Science, LILACS, BBO, Cochrane Library, and SIGLE. We also surveyed gray literature without restrictions. We meta-analyzed the data using the random-effects model to compare potassium nitrate and placebo in terms of risk and intensity of TS and color change (∆SGU or ∆E). The quality of the evidence was rated using the GRADE approach. The risk of bias (RoB) of the included studies was analyzed using the Cochrane RoB tool.

RESULTS

After the database screening, 24 articles remained. A significant 12% lower risk for the groups where desensitizing agents were applied (p = 0.02), with a risk ratio of 0.88 (95% CI 0.78 to 0.98). About the intensity of TS, a significant average mean difference of - 0.77 units of VAS units (95%CI - 1.34 to - 0.19; p = 0.01) in favor of the desensitizer group. In the NRS scale, a significant average mean difference of - 0.36 (95% CI - 0.61 to - 0.12; p value = 0.004) in favor of the desensitizer group. No significant difference was observed in color change (p > 0.28) in ∆SGU and ∆E.

CONCLUSIONS

Although a significant reduction in the risk and intensity of TS was observed in groups treated with a potassium nitrate at some point during the bleaching, the clinical significance of this reduction is subtle and clinically questionable. Color change is not affected by the use of agents.

CLINICAL RELEVANCE

The reduction in the risk and intensity of TS with the topical application of potassium nitrate-based desensitizing agents in dental bleaching is subtle and maybe clinically questionable.

ATR-FTIR, EDS and SEM evaluations of enamel structure after treatment with hydrogen peroxide bleaching agents loaded with nano-hydroxyapatite particles

Background

Tooth whitening is one of the most requested dental treatments, but it still presents some side effects. Indeed, the bleaching agent can generate patients’ discomfort and dental hard tissue damages, not achieving an efficient and long-lasting treatment with optimum whitening effect. To overcome these limitations, the bleaching agents containing nano-hydroxyapatite can represent a reliable solution to avoid these detrimental effects.

Methods

In this study, human third molars were treated with commercial bleaching agents, containing nano-hydroxyapatite (nHA) and 6% (at-home treatment), 12% and 18% (in-office treatments) of hydrogen peroxide (HP), named respectively G1, G2 and G3. The results were evaluated descriptively and analytically using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray spectroscopy (EDS), comparing the treated groups with a commercial gel containing 10% carbamide peroxide (CONV) and with a non-treated control group (CTRL).

Results

ATR-FTIR analysis revealed a similar composition in carbonates and phosphates for CTRL, G1 and G2 groups, which showed no significant differences in their spectral profiles; an increased amount of organic matter was found in G3, while CONV displayed an intermediate behavior. SEM analysis did not highlight significant changes in the enamel microstructure of G1 and CONV when compared to CTRL; the pattern observed in G2 presented a slight increase of enamel irregularities, while G3 displayed a partial removal of the aprismatic layer and microporosities. No evident effects due to nHA were observed in the structure of the hydroxyapatite component of G1, G2 and CONV, if compared to CTRL, while G3 showed a slight loss of crystallinity. In all groups, EDS identified slight changes in the concentration of chemical elements O and Ca, while the Ca/P ratio was similar when compared to CTRL.

Conclusion

The obtained results suggest that the application of the tested commercial bleaching agents, with a concentration of HP up to 12%, does not alter the morphological and chemical composition of the enamel surface and maintains its crystallinity.

In vitro analysis of the pH stability of dental bleaching gels during in-office procedures

Background

Previous studies have shown that acidic bleaching gels could lead to worse collateral effects during an in-office bleaching procedure, while neutral or basic products leads towards a better experience. Considering this fact, the main purpose of this study was to evaluate the pH behavior of 6 in-office bleaching gels, compared to the information provided by their manufacturers.

Material and Methods

Thirty enamel discs of bovine teeth were prepared, the initial colors of which were measured by a spectrophotometer and then divided into 6 groups. A pH meter was used to measure the pH every 30 seconds until the end of each procedure, when a new color evaluation was then made. The Tukey test was used for statistical analysis of the results.

Results

There was no difference in the color variation (ΔE) between the groups (p> 0.05). In two groups, the pH variation (ΔpH) showed neutral stability, with initial and final pH averages of 7.04 and 7.11 (p = 0.08) and 7.21 and 7.19 (p = 0.55), respectively; in another, there was alkaline stability, with an initial and final pH average of 8.54 and 8.37 (p = 0.14). In the other three brands, however, the results showed acidification, with initial and final pH averages of 6.14 and 5.22 (p = 0.001), 6.05 and 5.16 (p = 0.001) and 7.14 and 5.83 (p = 0.001), respectively.

Conclusions

In 3 of the evaluated gels, a discrepancy existed between the manufacturer’s information and the data obtained, which could lead, considering previous studies discussed throughout this article, to unexpected collateral effects on the patients, especially dental sensitivity. Thus, clinicians and researchers should be aware about pH stability studies of in-office bleaching gels for better predictability and safety on their clinical usage.

Key words:Tooth bleaching, Bleaching agents, Hydrogen-ion concentration, Dentin sensitivity, Hydrogen peroxide.

Low-power laser and potassium oxalate gel in the treatment of cervical dentin hypersensitivity-a randomized clinical trial

OBJECTIVE

To evaluate the effectiveness of different protocols for the treatment of cervical dentin hypersensitivity (CDH) in non-carious cervical lesions (NCCLs).

MATERIALS AND METHODS

The CONSORT checklist was used to design this study. The sample with n = 74 participants (389 NCCLs) was randomly allocated into three groups: G1, potassium oxalate (Oxa-Gel BF); G2, GaAlAs (gallium-aluminum-arsenate) low-power laser (100 mW, 808nn, 60 J/cm²); and G3, potassium oxalate (Oxa-Gel BF) associated with the GaAlAs low-power laser. The CDH was triggered by the evaporative stimulus test (EST) and by the tactile stimulus test (TST). The visual analog scale (VAS) was used to quantify the degree of CDH. Changes in sensitivity were assessed from baseline over 3 weeks. Data were analyzed for NCCLs using mixed-effects models with unstructured direct product covariance structure (α = 0.05).

RESULTS

After the first application, participants from G1 and G3 had a reduction in CDH (p < 0.05) compared with group G2 for TST. After the second application, G3 participants had a reduction in CDH (p < 0.05) in relation to G2 for both stimuli. Reduction in CDH (p < 0.05) occurred over 3 weeks for EST and TST for all groups; however, there was no difference between groups at the end of the therapies.

CONCLUSION

Potassium oxalate was more effective in reducing immediate CDH. After four applications, all groups showed similar results for the reduction of CDH.

CLINICAL RELEVANCE

GaAlAS laser irradiation and oxalate potassium gel could reduce the symptoms of CDH; thus, they are viable alternatives for the treatment of this condition. Chemical occlusion of dental tubules showed effective results after a shorter time interval.

TRIAL REGISTRATION

Brazilian Clinical Trials Registration Platform under protocol number RBR-4ybjmt. http://www.braziliantrials.com/?keywords=RBR-4ybjmt&order=%7Eensaios.patrocinador_primario.

Alencar C, de Paula BLF, de A. Jassé FF, Araújo JLN, Silva CM. Photobiomodulation vs. Placebo on Post-Bleaching Sensitivity and Color Change: A Split-Mouth Clinical Study

Objective:

This study aimed to investigate the efficiency of Photobiomodulation (PBM) with low-level LASER therapy compared to placebo in post-bleaching sensitivity and color change during a three-week office bleaching treatment.

Methods:

A split-mouth model was used to evaluate 21 subjects. The right and left hemi-archs were randomized to one of two groups: GP (placebo): simulated LASER application followed by tooth bleaching with 35% hydrogen peroxide; and GL: treated with PBM followed by tooth bleaching with 35% hydrogen peroxide. A four-degree modified Visual Analog Scale (VAS) was used to assess tooth sensitivity after the application of an evaporative stimulus (stimulated pain). In addition, a daily questionnaire was used to measure unstimulated pain. The color change was measured using a spectrophotometer. The Friedman and Wilcoxon tests were used to analyze data sensitivity. Color results were statistically analyzed using Analysis Of Variance (ANOVA) followed by the Tukey post-hoc test.

Results:

There was no significant difference between GP and GL for stimulated pain evaluation (p> 0.05). However, there was a significant difference between the groups for unstimulated pain evaluation (p≤ 0.05). In addition, ΔE data did not reveal any significant difference in tooth color between groups at any time (p> 0.05).

Conclusion:

PBM prevented post-bleaching sensitivity compared to placebo, based on the daily pain assessment questionnaires. PBM did not compromise the quality of bleaching treatments.

Experimental gel containing bioactive glass-ceramic to minimize the pulp damage caused by dental bleaching in rats

Objectives

This study evaluated if the use of a bioactive glass-ceramic-based gel, named Biosilicate (BS), before, after or mixed with bleaching gel, could influence the inflammation of the dental pulp tissue of rats’ molars undergoing dental bleaching with hydrogen peroxide (H₂O₂).

Methodology

The upper molars of Wistar rats (Rattus norvegicus, albinus) were divided into Ble: bleached (35% H₂O₂, 30-min); Ble-BS: bleached and followed by BS-based gel application (20 min); BS-Ble: BS-based gel application and then bleaching; BS/7d-Ble: BS-based gel applications for 7 days and then bleaching; Ble+BS: blend of H₂O₂ with BS-based gel (1:1, 30-min); and control: placebo gel. After 2 and 30 days (n=10), the rats were euthanized for histological evaluation. The Kruskal-Wallis and Dunn statistical tests were performed (P<0.05).

Results

At 2 days, the Ble and Ble-BS groups had significant alterations in the pulp tissue, with an area of necrosis. The groups with the application of BS-based gel before H₂O₂ had moderate inflammation and partial disorganization in the occlusal third of the coronary pulp and were significantly different from the Ble in the middle and cervical thirds (P<0.05). The most favorable results were observed in the Ble+BS, which was similar to the control in all thirds of the coronary pulp (P>0.05). At 30 days, the pulp tissue was organized and the bleached groups presented tertiary dentin deposition. The Ble group had the highest deposition of tertiary dentin, followed by the Ble-BS, and both were different from control (P<0.05).

Conclusion

A single BS-based gel application beforehand or BS-based gel blended with a bleaching gel minimize the pulp damage induced by dental bleaching.

The effect of oral anti-inflammatory drugs on reducing tooth sensitivity due to in-office dental bleaching: A systematic review and meta-analysis

BACKGROUND

The authors' aim was to evaluate the effectiveness of anti-inflammatory drugs on tooth sensitivity (TS) during and after in-office dental bleaching procedures.

TYPES OF STUDIES REVIEWED

The authors selected randomized controlled trials in which the investigators compared anti-inflammatory drugs with a placebo to evaluate in-office dental bleaching TS. The authors performed an electronic search by using PubMed, ScienceDirect, and Embase. In addition, the authors searched other Web sites, such as ClinicalTrials.gov, to identify ongoing studies.

RESULTS

The authors included 7 randomized controlled trials (324 adults) in the review. According to the extracted data, the authors performed the meta-analysis by using risk ratios and their 95% confidence intervals or by using the mean difference with a 95% confidence interval. The authors used the Cochrane Collaboration's tool to assess study quality. After the evaluation, the authors considered 6 studies to be high quality and a single study to be low quality. The overall results of the evaluation process revealed the absence of a clinically significant effect of anti-inflammatory drugs.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

The results of this analytic process indicated that anti-inflammatory drugs have no clinically significant effect on the TS that occurs due to in-office bleaching. Readers must analyze these results carefully given the limitations of this review, such as the small samples size and the heterogeneity among the studies in some stages of the evaluation process. The results of this analytical study highlight the need for more clinical studies to reach a significant conclusion because TS is one of the most important reasons for the cessation of bleaching treatment.

Evaluation of post-bleaching hypersensitivity using desensitizing agent before and /or after in-office bleaching: A randomized clinical trial

Background: Dental bleaching has become one of the most demanded aesthetic procedures as it is very simple and gives fast results that satisfy the patient’s wishes. However, unfortunately, it has the annoying side effect of tooth sensitivity. This clinical trial was designed to evaluate the efficacy of using a desensitizing agent, which was applied during in-office bleaching with 30% HP (hydrogen peroxide). Methods: 36 participants were divided into four groups (N = 9). According to the intended intervention as follows: Group I:—Application of Relief ®Amorphous Calcium Phosphate (ACP) before in-office bleaching; Group II—Application of Relief ®ACP before and after in-office bleaching; Group III—Application of Relief ®ACP after in-office bleaching; and Group IV: placebo was applied before and after in-office bleaching.  Then, three hydrogen peroxide bleaching applications for a total of 45 minutes were performed. The primary outcome variable was hypersensitivity, assessed with (VAS) scale immediately and 24h, 1 week and 1 month after the procedure; while the secondary outcome was teeth shade assessed using the VITAPAN ® classical shade guide. Results: Statistical analysis was done using Kolmogorov-Smirnov, Shapiro-Wilk tests, Kruskal-Wallis test and Dunn’s test. Immediately after bleaching, there was statistically significant distinction in the median pain score between the groups. After 1 day, the ACP gel before and after bleaching group showed the lowest median score, while, the control group confirmed the highest median score. After 2 days, no statistically sizable difference was observed between all groups. The group receiving ACP gel before and after showed the highest change in median of classical shade guide scores while, (ACP gel after) and control group; showed the lowest change. Conclusion: The application of the desensitizing agent prior to and after in–office bleaching was successful in lowering post-bleaching hypersensitivity. Trail Registration: Clinical trial.gov NCT02942082 21/10/2016

Are combined bleaching techniques better than their sole application? A systematic review and meta-analysis

OBJECTIVES

A systematic review and meta-analysis were performed to answer this research question: "Does combined in-office (IO) and at-home (AH) bleaching produce improved color change and lower tooth sensitivity (TS) better than solely AH or IO bleaching in adults?"

MATERIAL AND METHODS

Randomized controlled trials in adults that compared combined versus sole application bleaching were included. The risk of bias (RoB) was evaluated using the Cochrane Collaboration tool. Meta-analyses were conducted for color change in shade guide units (∆SGU) and with a spectrophotometer (∆E*), risk, and intensity of TS, using the random effects model. Heterogeneity was assessed with Cochran's Q test and I² statistics. GRADE assessed the quality of the evidence. PubMed, Scopus, Web of Science, LILACS, BBO, Cochrane Library, SIGLE, IADR abstracts, unpublished, ongoing trial registries, dissertations, and theses were searched on August 28, 2017 (updated on January 29, 2019).

RESULTS

Twelve studies remained. Two were considered to have low RoB. For combined vs. IO bleaching, no significant difference for ∆E*, ∆SGU, and risk of TS were observed; data were not available to analyze the intensity of TS. For combined vs. AH bleaching, no significant difference for ∆E*, ∆SGU, but lower TS to risk (RR 1.40, 95% 1.10 to 1.80) and intensity (MD 1.40, 95% CI 0.18 to 2.63) were detected for AH bleaching. Quality of evidence was graded as low or very low in all meta-analyses.

CONCLUSION

Lower risk and intensity of TS was observed for the solely AH group without jeopardizing color change. However, more studies are still encouraged due to the low quality of evidence for most of the outcomes.

CLINICAL RELEVANCE

If clinicians are to choose between combined or sole AH bleaching, the solely AH may be preferable; combined bleaching may potentiate the risk of TS without benefits in color change. For combined or sole IO bleaching, no important clinical difference in color change and risk of TS were detected; however, intensity of TS could not be compared due to lack of data. Further studies should be conducted due to the low/very low quality of the evidence.

Effect of High Light Intensity Bleaching Protocol versus Descending Light Intensities Bleaching Protocol on Post Bleaching Teeth Sensitivity: A Randomized Clinical Trial

AIM

The study aimed to compare teeth sensitivity and shade after bleaching protocol with descending different light intensities versus bleaching protocol with the same high light intensity.

MATERIAL AND METHODS

Sample size was twenty-four patients. Each group consisted of twelve patients. Group, I patients received bleaching protocol of descending different light intensities. Group II patients received bleaching protocol with the same high light intensity; both groups used the same home bleaching gel kit for seven days according to manufacturer instructions and protocol. Baseline records were digital photographs, teeth sensitivity and teeth shade for 12 anterior teeth. Teeth sensitivity was assessed using five points verbal rating scale and Standardized 100 mm Visual analogue scale after 1 day, after 2 days and after 1 week. Teeth shades for twelve anterior teeth were recorded by VITA Easy Shade V (VITA Zahnfabrik H. Rauter GmbH & Co. KG, Germany) after 1 week by VITA Easy Shade V. Mann-Whitney test (non-parametric test, 2 independent samples) was used to compare teeth sensitivity between both bleaching protocols at each period. A paired t-test (parametric test, 2 related samples) was performed to compare the colour change in shade guide units (SGU) and ∆E values within high light intensity bleaching protocol. While Wilcoxon Signed-Rank test (non-parametric test, 2 related samples) was used to compare colour change light intensities bleaching protocol. Comparison of bleaching effectiveness (∆SGU and ∆Ediff) between both bleaching protocols was performed by the Mann-Whitney test.

RESULTS

Descending light intensities protocol showed a lower teeth sensitivity than high light intensity protocol after 1 and 2 days. There was no teeth sensitivity reported at 1-week post-bleaching. Regarding the teeth shade, descending light intensities protocol had a little higher effect on colour change in shade guide units (SGU) than high light intensity protocol effect. Both bleaching protocols showed there was no significant difference in ∆SGU recorded after bleaching between high and descending light intensities protocols.

CONCLUSION

Descending different light intensities protocol showed a lower teeth sensitivity than high same light intensity protocol. Descending light intensities protocol had a little higher effect on colour change in shade guide units (SGU) than high light intensity protocol effect.

Effect of dental bleaching on pulp oxygen saturation in maxillary central incisors - a randomized clinical trial

OBJECTIVE

To assess pulp oxygen saturation levels (SaO2) in maxillary central incisors after dental bleaching.

MATERIALS AND METHODS

80 participants (160 teeth) were randomly allocated to four groups: G1 In-office bleaching with two applications of 35% hydrogen peroxide (HP) (20 minutes), followed by at-home bleaching with 10% carbamide peroxide (CP) (2 hours/day for 16 days); G2 - Same protocol as G1, plus desensitizing toothpaste; G3 - In-office bleaching with 35% HP and one application of placebo gel (20 minutes), followed by at-home bleaching with 10% CP (2 hours/day for 16 days); and G4 - Same protocol as G3, plus desensitizing toothpaste. Pulp SaO2 levels were measured before (T0) and immediately after (T1) in-office bleaching; on the 5th (T2), 8th (T3), 12th (T4), and 16th days of at-home bleaching (T5); and on the 7th (T6) and 30th (T7) days. Mean (SD) pulp SaO2 levels were compared within groups by generalized estimating equations (GEE) and Student's t-test (P<0.05).

RESULTS

Mean pulp SaO2 at T0 was 84.29% in G1, 84.38% in G2, 84.79% in G3, and 85.83% in G4. At T1, these values decreased to 81.96%, 82.06%, 82.19%, and 81.15% in G1, G2, G3, and G4 respectively, with significant difference in G4 (P<0.05). During home bleaching, pulp SaO2 levels varied in all groups, with 86.55%, 86.60%, 85.71%, and 87.15% means at T7 for G1, G2, G3, and G4, respectively; G2 presented significant difference (P<0.05).

CONCLUSIONS

Pulp SaO2 level in maxillary central incisors was similar at baseline, reducing immediately after in-office bleaching, regardless of using desensitizing toothpaste and increasing at 30 days after dental bleaching.

Evaluation of in-office tooth whitening treatment with violet LED: protocol for a randomised controlled clinical trial

INTRODUCTION

In-office tooth whitening treatment using violet light emited diode (LED) (405 nm) is a novel bleaching method that causes less sensitivity while offering the same effectiveness as the gold standard (35% hydrogen peroxide, H₂O₂). This study describes a protocol for the first randomised controlled clinical trial to compare the effects of the two methods.

METHODS AND ANALYSIS

Eighty patients will be divided into four groups: G1 violet LED; G2 violet LED +35% carbamide peroxide; G3 35% H₂O₂ and G4 violet LED +gingivoplasty. Colour will be measured at baseline, immediately after the first session and at the 15 and 180 days follow-up using the Vita Classical and the digital Easyshade V spectrophotometer (Vita, Zahnfabrik, Germany). Sensitivity after whitening will be measured using the Visual Analogue Scale at baseline and at each session in all groups and in all follow-ups. The tissue removed during gingivoplasty (G4) will be submitted to immunohistochemical analysis for the determination of inflammatory changes caused by violet LED. The Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ) will be evaluated before, as well as at established time point controls. The results will be expressed as mean and SD values. After determining the normality of the data, a one-way repeated-measures analysis of variance will be used for the comparison of data with normal distribution and the Kruskal-Wallis test will be used for data with non-normal distribution. A p<0.05 will be considered indicative of statistical significance. After determining the normality of the data, the Kruskal-Wallis test will be used for non-parametric data. Multivariate analysis of variance (MANOVA) and the Wilcoxon test will be used for comparing data from the PIDAQ.

ETHICS AND DISSEMINATION

This protocol has been approved by the Human Research Ethics Committee of UniversidadeNove de Julho (certificate: 2.034.518). The findings will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT03192852; Pre-results.

Effect of CPP-ACP on efficacy and postoperative sensitivity associated with at-home vital tooth bleaching using 20% carbamide peroxide

OBJECTIVES

To evaluate CPP-ACP effect on colour change and tooth sensitivity (TS) associated with at-home vital tooth bleaching using 20% carbamide peroxide (CP).

METHODS

A randomised double-blind placebo-controlled clinical trial was conducted to measure the TS and tooth colour change of 24 patients at 3-day, 7-day, 14-day and 30-day periods. The participants were instructed to apply 20% CP (7 days-04 h each) followed by the application of either CPP-ACP or non-active placebo paste, delivered by the bleaching custom tray (7 days-30 min each). Lightness (L*), redness (a*) and yellowness (b*) were measured using a digital spectrophotometer and the overall colour changes ∆E were calculated. ∆E and TS values were statistically analysed. The level of statistical significance was established at p = 0.05.

RESULTS

No significant differences were detected between CPP-ACP and placebo groups regarding the ∆E. The ∆E measurements presented significant differences within CPP-ACP groups between 3-day vs. 14-day and 30-day measurements. The CPP-ACP application reduced significantly the TS reported by the participants at 3-day when compared with the placebo group.

CONCLUSION

The application of CPP-ACP paste during at-home tooth bleaching with 20% CP was beneficial since its use reduced the TS and presented no deteriorating effect on the colour change.

CLINICAL RELEVANCE

The current findings are of importance for clinicians to manage TS reported by patients when a high CP bleaching agent is used.

Effect of low-level laser therapy combined with 5000 parts per million fluoride dentifrice on postbleaching sensitivity: A clinical, randomized, and double-blind study

OBJECTIVE

The aim of this double-blind, randomized, controlled clinical study was to assess the efficacy of low-level laser therapy (LLLT) combined with 5000 ppm fluoride dentifrice on postbleaching sensitivity in teeth exposed to 35% hydrogen peroxide for four weeks.

MATERIALS AND METHODS

Twenty-five volunteers were evaluated using the split-mouth model in which the right and left maxillary/mandibular quadrants were randomized and allocated to one of two groups: GPLACEBO, in which the laser tip was positioned without the emission of light (placebo effect) + 5000 ppm sodium fluoride, or GLASER, which comprised LLLT + 5000 ppm sodium fluoride. For both groups, LLLT and placebo were used before bleaching, whereas fluoride was applied after bleaching. LLLT was applied at two points: on the central cervical and medial regions of the incisors, canines, and premolars in the corresponding hemi-arch. At each point, 60 J/cm² was applied for 16 seconds with an irradiance of 3.75 W/cm² using the therapeutic infrared device. To assess tooth sensitivity, a modified visual analogue scale was used after an evaporative stimulus, and a daily pain questionnaire was also applied.

RESULTS

The Wilcoxon and Friedman tests demonstrated a significant difference in the incidence of sensitivity pain between GPLACEBO and GLASER (P ≤ .05), with different evaluation times.

CONCLUSION

Teeth treated with laser therapy in combination with the topical use of sodium fluoride at each bleaching session demonstrated less sensitivity compared with the application of sodium fluoride only.

CLINICAL SIGNIFICANCE

The use of a low-level laser therapy in combination with topical use of sodium fluoride improves symptoms of dentin sensitivity at each bleaching session.

High-concentration carbamide peroxide can reduce the sensitivity caused by in-office tooth bleaching: a single-blinded randomized controlled trial

Objectives

A single-blinded, randomized, parallel clinical trial evaluated the use of 37% carbamide peroxide (CP) on bleaching effectiveness and tooth sensitivity reported by patients undergoing in-office tooth bleaching, in comparison with the results of using 35% hydrogen peroxide.

Material and Methods

Forty patients were allocated to receive two sessions of in-office tooth bleaching using either 35% hydrogen peroxide (HP) or 37% CP. Each patient’s sensitivity level was evaluated during and up to 24 h after bleaching. The effectiveness of the bleaching procedures was evaluated with a spectrophotometer one week after each session and 30 days after the last session. The impact of tooth bleaching on the patients’ perceptions regarding smile changes, in addition to the bleaching procedures and their results, were also recorded. Absolute and relative sensitivity risks were calculated. Data on sensitivity level were analyzed using the Mann-Whitney or T-test, and data from the color evaluation were subjected to 2-way repeated measures ANOVA.

Results

The use of CP reduced the risk and level of tooth sensitivity to values close to zero, whereas the difference between the bleaching agents disappeared after 24 h. An increased bleaching effect was observed for HP, mainly due to an improved reduction of redness and yellowness. Participants perceived improved tooth bleaching for HP and reduced sensitivity for CP, but no differences regarding the comfort of the techniques were noted.

Conclusions

In our study, 37% CP resulted in reduced tooth sensitivity but decreased the tooth bleaching effectiveness. However, both bleaching agents resulted in high levels of patient satisfaction.

Novel treatment of in-office tooth bleaching sensitivity: A randomized, placebo-controlled clinical study

OBJECTIVES

Aim of this clinical trial was to investigate the effect of a calcium phosphate based desensitizer paste applied prior to in-office tooth whitening on bleaching sensitivity (BS).

METHODS

This crossover study was designed as randomized double-blinded, placebo-controlled trial. The desensitizer paste Teethmate AP (TAP) contains tetracalcium phosphate and dicalcium phosphate anhydrous in glycerol and polyethylene glycol, whereas placebo (PLA) is a calcium phosphate free analog. Fifty patients with sound maxillary incisors and canines were enrolled. Tooth shades were determined with a Vitapan Classic Shade guide. Randomly, TAP and PLA were applied to the left or to the right anterior teeth. After rinsing and air-drying the bleaching gel (Opalescence Boost PF 40%) was applied and left on the labial surfaces for 15 minutes. Sensitivity was recorded using a 10 cm visual analog scale (VAS) before, at 5, 10, and 15 minutes during, and at 1 hour, 1, 2, and 7 days after bleaching. Tooth whitening was determined with the shade guide after 1 day and 1 week.

RESULTS

Prebleaching desensitization with TAP reduced BS significantly when compared with PLA. Between 1 and 7 days the average sensitivity scores were close to zero, whereas the average scores for PLA were significantly higher during this time interval. Independent from the desensitizing treatment after 1 and 7 days the medians of the shades were between 5 and 3.5 units brighter.

CONCLUSIONS

Prebleaching desensitization with TAP was effective in reducing BS during and after tooth whitening treatment and had no adverse effect on the bleaching result.

CLINICAL SIGNIFICANCE

Prebleaching topical application of a calcium phosphate containing compound reduced significantly bleaching sensitivity during a single 15 minutes treatment and up to one week with a 40% hydrogen peroxide containing gel without compromising tooth whitening.

Influence of pH, bleaching agents, and acid etching on surface wear of bovine enamel

Development of new materials for tooth bleaching justifies the need for studies to evaluate the changes in the enamel surface caused by different bleaching protocols.

Bioactive and inert dental glass-ceramics

The global market for dental materials is predicted to exceed 10 billion dollars by 2020. The main drivers for this growth are easing the workflow of dentists and increasing the comfort of patients. Therefore, remarkable research projects have been conducted and are currently underway to develop improved or new dental materials with enhanced properties or that can be processed using advanced technologies, such as CAD/CAM or 3D printing. Among these materials, zirconia, glass or polymer-infiltrated ceramics, and glass-ceramics (GCs) are of great importance. Dental glass-ceramics are highly attractive because they are easy to process and have outstanding esthetics, translucency, low thermal conductivity, high strength, chemical durability, biocompatibility, wear resistance, and hardness similar to that of natural teeth, and, in certain cases, these materials are bioactive. In this review article, we divide dental GCs into the following two groups: restorative and bioactive. Most restorative dental glass-ceramics (RDGCs) are inert and biocompatible and are used in the restoration and reconstruction of teeth. Bioactive dental glass-ceramics (BDGCs) display bone-bonding ability and stimulate positive biological reactions at the material/tissue interface. BDGCs are suggested for dentin hypersensitivity treatment, implant coating, bone regeneration and periodontal therapy. Throughout this paper, we elaborate on the history, processing, properties and applications of RDGCs and BDGCs. We also report on selected papers that address promising types of dental glass-ceramics. Finally, we include trends and guidance on relevant open issues and research possibilities. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 619-639, 2017.

At-home vs In-office Bleaching: A Systematic Review and Meta-analysis

OBJECTIVE

A systematic review and meta-analysis were performed to evaluate the risk and intensity of tooth sensitivity during in-office and at-home bleaching in adult patients. The efficacy of dental bleaching was also evaluated.

METHODS

A comprehensive search was performed in the MEDLINE via PubMed, Scopus, Web of Science, Latin American and Caribbean Health Sciences Literature database, Brazilian Library in Dentistry, Cochrane Library, and System for Information on Grey Literature in Europe without restrictions. The annual conference of the International Association for Dental Research abstracts (1990-2014) and unpublished and ongoing trials registry were also searched. Dissertations and theses were searched using the ProQuest Dissertations and Periódicos Capes Theses databases. Only randomized clinical trials that compared the prevalence or intensity of tooth sensitivity during in-office and at-home bleaching in adult patients were included and studies that evaluated the efficacy of these dental bleaching techniques, in terms of shade guide units (ΔSGU) and in terms of color difference measured with a spectrophotometer (ΔE*).

RESULTS

After the removal of duplicates, 1139 articles were identified. After title and abstract screening, 29 studies remained. Fifteen studies were further excluded, whereas 12 studies remained for qualitative analyses and 8 for the meta-analysis of the primary and secondary outcomes. No significant difference in the risk/intensity of tooth sensitivity or in bleaching efficacy was observed in the present study.

CONCLUSION

In an overall comparison of at-home and in-office bleaching, no differences were detected, either regarding risk/intensity of tooth sensitivity or the effectiveness of the bleaching treatment. This comparison, however, does not take into consideration variations in the protocols (daily usage time, number of bleaching sessions, and product concentration) of the bleaching techniques in the studies included.

Combined Bleaching Technique Using Low and High Hydrogen Peroxide In-Office Bleaching Gel

Objectives: The aim of this study was to evaluate the efficacy, color stability, risk, and intensity of tooth sensitivity (TS) of combined bleaching techniques performed with 20% or 35% hydrogen peroxide for an in-office protocol.

Methods: Thirty patients were randomly divided into two groups and submitted to a single 45-minute in-office bleaching session with 35% hydrogen peroxide or 20% hydrogen peroxide. At-home bleaching was performed with 10% carbamide peroxide for two hours daily over the course of two weeks. The color was evaluated with the value-oriented shade guide Vita Classical at different periods up to 12 months after bleaching. Patients recorded the intensity of TS using a five-point verbal scale. Color change data were submitted to a two-way repeated-measures analysis of variance and Tukey test (α=0.05). The absolute risk and intensity of TS were compared with the Fisher exact test and Mann-Whitney test, respectively (α=0.05).

Results: On average, an effective and similar whitening of three units in shade guide was observed for both groups, which remained stable for 12 months. When both protocols were compared, the one with hydrogen peroxide 35% showed a higher risk (p=0.02) and intensity of TS (p=0.04). In regard to the TS intensity, no significant difference was observed up to 48 hours after in-office bleaching (p=0.09) and during the at-home bleaching phase of the study (p=0.71).

Conclusion: The combined bleaching technique using at-home bleaching associated with in-office bleaching was effective and stable over the course of 12 months, regardless of the concentration of the hydrogen peroxide used for in-office bleaching. However, the protocol with 20% hydrogen peroxide produced lower risk and intensity of TS.