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.

Evaluation of At-home Bleaching Times on Effectiveness and Sensitivity with 10% Hydrogen Peroxide: A Randomized Controlled Double-blind Clinical Trial

OBJECTIVES

The aim of this randomized double-blind controlled clinical trial was to evaluate different protocols for at-home use of 10% hydrogen peroxide in whitening effectiveness and tooth sensitivity.

METHODS

Seventy-two patients were selected according to the inclusion and exclusion criteria, with the upper central incisors having color A2 or darker according to the Vita Classical scale (VITA Zahnfabrik, Bad Säckingen, Germany) and randomized into two groups: 10% hydrogen peroxide applied once daily for 15 minutes (HP 15) or applied once daily for 30 minutes (HP 30). Bleaching was performed for 14 days in both groups. The color was evaluated before bleaching, during bleaching (1st and 2nd weeks), and 1 month after the bleaching treatment using the Vita Classical, Vita Bleachedguide 3D-MASTER, and Vita Easyshade spectrophotometer (VITA Zahnfabrik). Dental sensitivity was recorded by the patients using the numerical rating scale (0-4) and visual analogue scale (0-10 cm). Color data were evaluated by two-way analysis of variance (ANOVA) of repeated measures (group vs. treatment time). The Mann-Whitney test was performed to contrast the means (α=0.05). Tooth sensitivity was assessed by Fisher's exact test (p=1.00) and intensity of tooth sensitivity was evaluated by the Mann-Whitney test (α=0.05) for both scales.

RESULTS

A significant whitening effect was observed after 2 weeks of bleaching for all color measurements (p=0.01), with no difference between HP 15 and HP 30 (p>0.05). Also, the absolute risk and intensity of tooth sensitivity were similar (47%; p>0.05).

CONCLUSIONS

The effectiveness and tooth sensitivity of at-home bleaching carried out with 10% hydrogen peroxide applied for 15 minutes or 30 minutes are similar.

Effectiveness of and Dental Sensitivity to At-home Bleaching With 4% and 10% Hydrogen Peroxide: A Randomized, Triple-blind Clinical Trial

OBJECTIVES

To evaluate the risk for and intensity of tooth sensitivity and color change of at-home dental bleaching with 4% and 10% hydrogen peroxide (HP).

METHODS

For this study, 78 patients were selected according to the inclusion and exclusion criteria and randomized into two groups: HP 4 (White Class 4%, FGM) and HP 10 (White Class 10%, FGM). In both groups, the at-home bleaching was performed for a period of 30 minutes twice a day for two weeks. The color was assessed by Vita Classical, Vita Bleachedguide 3D-MASTER and spectrophotometer Vita Easyshade (Vita Zahnfabrik) at baseline, during bleaching (first and second weeks) and after bleaching (one month). Patients recorded their tooth sensitivity using a numeric rating scale (0-4) and visual analog scale (0-10). Data from color change (DeltaE data) was submitted to two-way analysis of variance. The color change data in Delta SGU from the two shade guide units were compared with the Mann Whitney test. The risk of tooth sensitivity was evaluated by χ² test and the intensity of tooth sensitivity from both scales was evaluated by a Mann-Whitney test (α=0.05).

RESULTS

The absolute risk and intensity of tooth sensitivity was higher in the group that used HP 10 than the one that used HP 4. Data from change in the number of shade guide units and color variation after one month of bleaching for both groups showed significant whitening, with no difference between groups.

CONCLUSIONS

At-home bleaching is effective with 4% and 10% HP concentrations, but 10% HP increased the absolute risk and intensity of tooth sensitivity during at-home bleaching.

Combination of Acetaminophen/Codeine Analgesics Does Not Avoid Bleaching-Induced Tooth Sensitivity: A Randomized, Triple-Blind Two-Center Clinical Trial

Bleaching-induced tooth sensitivity (TS) is highly prevalent.

OBJECTIVE

This study aimed to determine if the combination of opioids and nonopioids analgesics (Tylex) may provide a better analgesic effect.

METHOD

A triple-blind, parallel, randomized two-center clinical trial was conducted with 105 healthy patients who received either a placebo or a combination of acetaminophen/codeine. The first dose of Tylex 30 mg (acetaminophen 500 mg/codeine 30 mg) or placebo was administered one hour before the in-office bleaching (35% hydrogen peroxide), and extra doses were administered every six hours for 48 hours. The TS was recorded using a visual analog scale of 0 to 10 and a numeric rating scale of 0 to 4 in different periods: during bleaching, one hour up to 24 hours, and 24 hours up to 48 hours postbleaching. The color was measured before and one month after dental bleaching with a visual shade guide (Vita Classical), Vita Bleachedguide 3D-MASTER, and the spectrophotometer Vita Easyshade. The absolute risk of TS was evaluated using the Fisher exact test. Data of TS intensity with numeric rating scale of the two groups were compared with the Mann-Whitney U-test and the Friedman test, while data from the visual analog scale were evaluated by two-way repeated measures analysis of variance and the Tukey test for pairwise comparison. The color changes between groups were compared using the Student t-test (α=0.05).

RESULTS

No significant differences between the groups were observed in the risk and intensity of TS. The overall absolute risk of TS was approximately 96%. No significant differences between groups were observed in terms of color change ( p>0.05) for any scale.

CONCLUSION

The use of an acetaminophen/codeine combination prior to in-office bleaching does not reduce the risk and intensity of bleaching-induced TS.

Effects of At-home Bleaching in Smokers: 30-month Follow-up

Objective:

This clinical study evaluated the color longevity after 30 months of at-home bleaching with 10% carbamide peroxide (CP) in smokers and nonsmokers.

Methods:

Sixty patients, 30 smokers and 30 nonsmokers, were subjected to bleaching with 10% CP (Whiteness Perfect–FGM) for three hours daily for three weeks. The color was measured at baseline and at one month and 30 months after the completion of dental bleaching using the shade guide Vita classical organized by value (ΔSGU) and the shade guide Vita Bleachedguide 3D-MASTER. At the 30-month recall, the color was assessed before and after dental prophylaxis. Data from color evaluation were analyzed by two-way repeated-measures analysis of variance and Tukey test for the contrast of means (α=0.05).

Results:

Twenty-one smokers and 22 nonsmokers attended the 30 month recall. For both shade guides, only the main factor of assessment time was statistically significant (p<0.001). Effective whitening was observed in both groups at the baseline, which was stable at one month. However, color rebound was observed after 30 months for both groups of participants when color was measured before and after dental prophylaxis.

Conclusion:

Thirty months after at-home bleaching with 10% CP gel, dental darkening was detected in both groups, which cannot be solely attributed to stains caused by extrinsic staining from daily food, drinks, and smoke (in smokers).

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.

Evaluation of Genotoxicity and Efficacy of At-home Bleaching in Smokers: A Single-blind Controlled Clinical Trial

Objective

This single-blind controlled study evaluated the genotoxicity and efficacy of at-home bleaching in smokers and nonsmokers.

Methods

We selected 60 patients with central incisors A2 or darker: 30 smokers (experimental group) and 30 nonsmokers (control group). The bleaching was carried out with 10% carbamide peroxide for three hours a day for three weeks. The color was evaluated using a shade guide, Vita Bleachedguide 3D-Master, at baseline, during bleaching (first, second, and third weeks), and one week and one month after bleaching. Smears were obtained with a moistened wooden spatula from marginal gingiva. All the cytologic smears were stained with Giemsa solution. From each slide, 1000 cells were examined under 40× magnification and where micronuclei (MN) were located, they were examined under 100× magnification. The change in shade guide units at the different assessment periods and the frequency of MN were subjected to a two-way repeated measures analysis of variance and Tukey test (α=0.05).

Results

In both groups we detected a whitening of approximately 4 to 5 shade guide units, without color rebound after one month (p>0.05). The frequency of MN was significantly higher in the experimental group than in the control group, regardless of the bleaching treatment (p>0.001).

Conclusion

The efficacy of bleaching does not appear to be affected by the smoking habit. Additionally, at-home bleaching did not induce DNA damage to the gingival tissue during the bleaching period.

Effects of light activated in-office bleaching on permeability, microhardness, and mineral content of enamel

The aim of this study was to evaluate the permeability (PE), microhardness (KHN), and mineral change in enamel after LED/laser activated in-office bleaching. For PE, the coronal portion of premolars (n=51) was subjected to bleaching with 35% hydrogen peroxide (Whiteness HP Maxx, FGM Dental Products, Joinville, SC, Brazil). The samples were stained via the histochemical method, which involves a copper sulphate solution and rubeanic acid. The penetration of dye into the enamel was measured. The KHN of enamel was assessed before treatment, immediately after the bleaching treatment, and again after one week. The calcium and phosphorus content were analyzed with a scanning electron microscope with energy-dispersive X-ray (JSM 6360LV, Jeol Ltd, Tokyo, Japan). The data set from each test was subjected to appropriate parametric statistical analysis (α=0.05). No significant differences were observed for PE in NLA and LA compared to the control group (p=0.98), as well as for calcium (p=0.16) and phosphorus (p=0.80) content. Significant reduction of KHN after bleaching occurred for both groups (p<0.001). After immersion in artificial saliva, the KHN of the enamel for all groups was similar to that seen before bleaching. Light activation during in-office bleaching does not produce significant changes in the enamel compared to a non-light-activated technique.

Administration of Ascorbic Acid to Prevent Bleaching-induced Tooth Sensitivity: A Randomized Triple-blind Clinical Trial

This study evaluated the effect of ascorbic acid, 500 mg every eight hours, on bleaching-induced tooth sensitivity. A triple-blind, parallel design, and placebo-controlled randomized clinical trial was conducted on 39 adults. The pills (placebo or ascorbic acid) were administered three times per day for 48 hours; the first dose was given one hour prior to each bleaching session. Two bleaching sessions with 35% hydrogen peroxide gel were performed with a one-week interval. Tooth sensitivity was recorded up to 48 hours after bleaching. The color evaluation was performed before and 30 days after bleaching. The absolute risk and intensity of tooth sensitivity were evaluated by Fisher exact and Mann-Whitney U-tests, respectively. Color changes were evaluated by unpaired t-test (α=0.05). There were no significant differences in the absolute risk and intensity of tooth sensitivity and color change between the groups. Both groups showed a similar risk of tooth sensitivity (p&gt;0.05). The perioperative use of an antioxidant, such as ascorbic acid (500 mg, three times daily) perorally, was not able to prevent bleaching-induced tooth sensitivity or reduce its intensity.

The Effect of Perioperative Ibuprofen Use on Tooth Sensitivity Caused by In-Office Bleaching

Objective:

This study determined the effect of the administration of perioperative ibuprofen 400 mg on tooth sensitivity caused by in-office bleaching.

Methods:

A triple-blind, parallel-design, randomized clinical trial was conducted on 30 adults who received placebo or ibuprofen before and after bleaching. The drugs were administered three times per day for 48 hours; the first dose was given one hour prior to the bleaching treatment. Two bleaching sessions with 35% hydrogen peroxide gel were performed with a one-week interval. Tooth sensitivity was recorded on two scales: visual analogue and five-point verbal rating scale up to 48 hours after bleaching. The shade evaluation was performed with a visual shade guide and spectrophotometer, before and 30 days after bleaching. The absolute risk of tooth sensitivity and its intensity were evaluated by Fisher exact and Mann-Whitney tests, respectively. The shade changes were evaluated by Student's t-test.

Results:

Both groups showed similar absolute risk of tooth sensitivity (p&gt;0.05). Lower tooth sensitivity was observed in the experimental group only up to one hour postbleaching (p=0.04). Similar tooth sensitivity was observed in the other periods of time.

Conclusion:

The perioperative use of the anti-inflammatory ibuprofen was not able to avoid tooth sensitivity but reduced its intensity up to one hour after bleaching.

Clinical Effects of Exposure to Coffee During At-home Vital Bleaching

The purpose of the present study was to evaluate whether exposure to coffee during bleaching treatment with 16% carbamide peroxide (CP) affects the degree of whitening and tooth sensitivity. Forty patients with central incisors darker than A2 were selected. Participants who did not drink coffee were assigned to the control group (CG), while participants who drink coffee at least twice a day were assigned to the experimental group (EG). For CG, foods with dyes were restricted. For EG there was no restriction on food and patients were asked to make coffee rinses for 30 seconds, four times daily. For both groups 16% CP was used for a period of three hours daily for three weeks. Shade evaluation was assessed visually by Vita classical shade guide and by the Easyshade spectrophotometer at baseline, during bleaching (first, second, and third weeks), and postbleaching (one week and one month). Patients recorded their sensitivity perceptions by means of the numerical rating scale and 0-10 visual analog scales. Variation in shade guide units and the two colors (ΔE) were evaluated by two-way analysis of variance and Tukey tests (α=0.05). Absolute risk of tooth sensitivity and intensity of tooth sensitivity was evaluated by Fisher exact and Mann-Whitney tests (α=0.05). Effective bleaching was observed for both groups after three weeks, without statistical difference. No difference in terms of risk of tooth sensitivity and intensity of tooth sensitivity was detected between groups. Approximately 57% of the participants experienced tooth sensitivity, which was recorded mainly as “mild.” Exposure to coffee during bleaching treatment does not seem to affect the degree of bleaching and tooth sensitivity.

Efficacy of and effect on tooth sensitivity of in-office bleaching gel concentrations: a randomized clinical trial

With the aim of reducing the side effects of in-office bleaching agents, less-concentrated hydrogen peroxide (HP) gels have been released by manufacturers. We evaluated the tooth sensitivity (TS) and bleaching efficacy (BE) of two HP concentrations in this study. Gels containing 35% and 20% HP (HP35 and HP20, respectively) were applied on teeth of 60 caries-free patients. Color was recorded at baseline and one week after the first and second bleaching sessions using the Vita Classical shade guide. TS was recorded on a 0-4 scale. BE at each weekly recall was evaluated by Kruskall-Wallis and Mann-Whitney tests (α=0.05). Absolute risk of TS and its intensity was evaluated by Fisher exact and Mann-Whitney tests, respectively (α=0.05). After two bleaching sessions, color change of approximately eight tabs was obtained with HP35; whereas, with HP20 it was six tabs (p<0.05). Only 26.7% (HP35) and 16.7% (HP20) of the participants reported TS, and no statistical differences were detected among them. Both in-office bleaching gels showed similar TS intensity, but the 35% HP agent produced faster bleaching.

Clinical effects of prolonged application time of an in-office bleaching gel

OBJECTIVE

The aim of this study was to evaluate whether the use of a gel applied for 1 × 45 minutes would have the same bleaching rate and tooth sensitivity levels when compared with 3 × 15-minute applications.

METHODS

In-office bleaching was performed in 30 participants with 35% hydrogen peroxide gel. In one group (n=15; 3 x 15 minutes), the bleaching agent was refreshed every 15 minutes, three times at each bleaching appointment. In the other group (n=15; 1 x 45 minutes) the gel was left undisturbed on the buccal surfaces of all teeth for 45 minutes at each bleaching appointment. This protocol was repeated after one week. The bleaching evaluation was completed by two blinded, calibrated evaluators who compared the baseline color of the maxillary anterior teeth with a value-oriented shade guide after each period. The patients recorded the tooth sensitivity on a 0-4 scale. The color changes were evaluated by appropriate tests (α=0.05). The percentage of patients with tooth sensitivity and its intensity were also statistically analyzed (α=0.05), respectively.

RESULTS

The use of gel for a single 45-minute period (1 x 45 minutes) decreased the bleaching efficacy (p<0.05) 86.7%, and 100% of patients from the 3 × 15-minute and 1 × 45-minute groups, respectively, experienced tooth sensitivity (p=0.22). The intensity of sensitivity was lower for the 3 × 15-minute applications (p=0.04).

CONCLUSIONS

A 35% hydrogen peroxide gel for in-office bleaching preferably should be applied in three 15-minute applications because 1 × 45 minutes reduces the bleaching speed and slightly increases the intensity of tooth sensitivity.

Effect of light activation on tooth sensitivity after in-office bleaching

This clinical study evaluated the effects of light-emitting diode (LED)/laser activation on bleaching effectiveness (BE) and tooth sensitivity (TS) during in-office bleaching. Thirty caries-free patients were divided into two groups: light-activated (LA) and non-activated (NA) groups. A 35% hydrogen peroxide gel (Whiteness HP Maxx, FGM Dental Products, Joinville SC, Brazil) was used in three 15-minute applications for both groups. For the LA group, LED/laser energy (Whitening Lase Light Plus, DMC Odontológica, São Carlos SP, Brazil) was used, in accordance with the manufacturer's directions. Two sessions of bleaching were performed at one-week intervals. Color was registered at baseline and after the first and second bleaching sessions using a Vita shade guide. Patients recorded TS on a 0 to 4 scale during bleaching and within the next 24 and 48 hours of each session. BE at recall each week and intensity of TS were evaluated by repeated measures analysis of variance (ANOVA) and Tukey tests (α=0.05). Tooth sensitivity was compared using the Friedman repeated measures analysis of variance by rank and the Wilcoxon sign-ranked test. Faster bleaching was observed for the LA group than for the NA group after the first session (4.8 and 3.8 shade guide units [SGUs]; p=0.0001). However, both techniques were capable of bleaching the same number of SGUs after the second bleaching session (p=0.52). Most of the LA group (53.3%) had sensitivity even 24 hours after each bleaching session, but only 26.6% from the NA group reported TS. The intensity of TS was similar for both groups immediately after bleaching but significantly higher for the LA group 24 hours after each bleaching session (p=0.001). After two bleaching sessions, the use of LED/laser light activation did not improve bleaching speed. Persistent tooth sensitivity and higher tooth sensitivity after 24 hours of bleaching were observed when light activation was used.

Assessment of Tooth Sensitivity Using a Desensitizer Before Light-activated Bleaching

The use of a desensitizing gel before light-activated in-office bleaching does not eliminate, but may reduce, the duration of this side effect.