Influence of coating dental enamel with a TiF4-loaded polymeric primer on the adverse effects caused by a bleaching gel with 35% H2O2

OBJECTIVE

To evaluate whether coating enamel with a polymeric primer (PPol) containing titanium tetrafluoride (TiF4) before applying a bleaching gel with 35% H2O2 (35% BG) increases esthetic efficacy, prevents changes in morphology and hardness of enamel, as well as reduces the cytotoxicity from conventional in-office bleaching.

MATERIALS AND METHODS

Standardized enamel/dentin discs were stained and bleached for 45 min (one session) with 35% BG. Groups 2TiF4, 6TiF4, and 10TiF4 received the gel on the enamel previously coated with PPol containing 2 mg/mL, 6 mg/mL, or 10 mg/mL, respectively. No treatment or application of 35% BG directly on enamel were used as negative control (NC), and positive control (PC), respectively. UV-reflectance spectrophotometry (CIE L*a*b* system, ΔE00, and ΔWI, n = 8) determined the bleaching efficacy of treatments. Enamel microhardness (Knoop, n = 8), morphology, and composition (SEM/EDS, n = 4) were also evaluated. Enamel/dentin discs adapted to artificial pulp chambers (n = 8) were used for trans-amelodentinal cytotoxicity tests. Following the treatments, the extracts (culture medium + bleaching gel components diffused through the discs) were collected and applied to odontoblast-like MDPC-23 cells, which were assessed concerning their viability (alamarBlue, n = 8; Live/Dead, n = 4), oxidative stress (n = 8), and morphology (SEM). The amount of H2O2 in the extracts was also determined (leuco crystal violet/peroxidase, n = 8). The numerical data underwent one-criterion variance analysis (one-way ANOVA), followed by Tukey's test, at a 5% significance level.

RESULTS

Regarding the ΔE00, no difference was observed among groups 2TiF4, 6TiF4, and PC (p > 0.05). The ΔWI was similar between groups 2TiF4 and PC (p > 0.05). The ΔWI of group 6TiF4 was superior to PC (p < 0.05), and group 10TiF4 achieved the highest ΔE00 and ΔWI values (p < 0.05). Besides limiting enamel microstructural changes compared to PC, group 10TiF4 significantly increased the hardness of this mineralized dental tissue. The highest cellular viability occurred in 10TiF4 compared to the other bleached groups (p < 0.05). Trans-amelodentinal H2O2 diffusion decreased in groups 2TiF4, 6TiF4, and 10TiF4 in comparison with PC (p < 0.05).

CONCLUSION

Coating enamel with a PPol containing TiF4 before applying a 35% BG may increase enamel microhardness and esthetic efficacy and reduce the trans-amelodentinal cytotoxicity of conventional in-office tooth bleaching. The PPol containing 10 mg/mL of TiF4 promoted the best outcomes.

Bleaching versus color change resistant adhesive in the discoloration of bracket-bonded tooth surfaces: an in vitro study

OBJECTIVES

The aim of this study was to compare the effect of office bleaching of teeth bonded with Transbond XTTM (3M Unitek, Monrovia, CA, USA) (TRXT) and the use of color change resistant Orthocem (FGM, Joinville, Brazil) in bracket bonding on coffee-induced enamel discoloration.

MATERIALS AND METHODS

Eighty premolars were distributed in equal numbers (n = 20) to group 1 (TRXT + distilled water), group 2 (TRXT + coffee solution), group 3 (TRXT + coffee solution + bleaching), and group 4 (Orthocem + coffee solution). Color was measured using a SpectroShade Micro (MHT, International, Verona, Italy) device at the beginning (T0), after coloring (T1), after bleaching (T1B), and after debonding (T2). ΔE color change values were calculated as T1-T0, T1B-T0 and T2-T0 differences. The conformity of the data to the normal distribution was examined with the Shapiro-Wilk test. Multiple comparisons were made with Tamhane's T2 test and Tukey's HSD test using one-way analysis of variance in the comparison of normally distributed data, and multiple comparisons were made with Dunn's test using the Kruskal-Wallis H test for comparison of non-normally distributed data. The significance level was set at p < 0.050.

RESULTS

A statistically significant (p < 0.001) difference was found between the T1-T0 and T2-T0 stages for group 1-4 ΔE values. A statistically significant (p < 0.001) difference was also found when the T1B-T0 ΔE values of group 3 were compared with the T1-T0 ΔE values of groups 1, 2, and 4.

CONCLUSIONS

After coffee-induced enamel discoloration, bleaching of teeth bonded with TRXT produced acceptable color difference of the incisal, middle, and gingival regions of the crown. In teeth bonded with Orthocem, acceptable color difference was seen only in the middle of the crown.

CLINICAL RELEVANCE

The presented study will guide the clinician on how enamel discoloration side effect of fixed orthodontic appliance can reduce.

Enamel changes of bleached teeth following application of an experimental combination of chitosan-bioactive glass

BACKGROUND

Considering the extensive use of bleaching agents and the occurrence of side effects such as enamel demineralization, this study aimed to assess the enamel changes of bleached teeth following the experimental application of chitosan-bioactive glass (CH-BG).

METHODS

In this in vitro study, CH-BG (containing 66% BG) was synthesized and characterized by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Thirty sound human premolars were bleached with 40% hydrogen peroxide, and the weight% of calcium and phosphorus elements of the buccal enamel surface was quantified before and after bleaching by scanning electron microscopy/ energy-dispersive X-ray spectroscopy (SEM, EDX). Depending on the surface treatment of the enamel surface, the specimens were divided into three groups (n = 10): control (no treatment), MI Paste (MI), and CH-BG. Then the specimens were stored in artificial saliva for 14 days. The SEM/EDX analyses were performed again on the enamel surface. Data were analyzed by one-way ANOVA and Tukey's test and a p-value of < 0.05 was considered statistically significant.

RESULTS

In all groups, the weight% of calcium and phosphorus elements of enamel decreased after bleaching; this reduction was significant for phosphorus (p < 0.05) and insignificant for calcium (p > 0.05). After 14 days of remineralization, the weight% of both calcium and phosphorus elements was significantly higher compared to their bleached counterparts in both MI and CH-BG groups (p < 0.05). Following the remineralization process, the difference between MI and CH-BG groups was not significant (p > 0.05) but both had a significant difference with the control group in this regard (p < 0.05).

CONCLUSIONS

The synthesized CH-BG compound showed an efficacy comparable to that of MI Paste for enamel remineralization of bleached teeth.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

PRACTICAL IMPLICATIONS

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

In-office dental bleaching in adolescents using 6% hydrogen peroxide with and without gingival barrier: a randomized double-blind clinical trial

BACKGROUND

At low concentrations used for in-office bleaching gels, such as 6% HP, gingival barrier continues to be performed. If we take into account that, in the at-home bleaching technique, no barrier is indicated, it seems that the use of a gingival barrier fails to make much sense when bleaching gel in low concentration is used for in-office bleaching.

OBJECTIVE

This double-blind, split-mouth, randomized clinical trial evaluated the gingival irritation (GI) of in-office bleaching using 6% hydrogen peroxide (HP) with and without a gingival barrier in adolescents, as well as color change and the impact of oral condition on quality of life.

METHODOLOGY

Overall, 60 participants were randomized into which side would or would not receive the gingival barrier. In-office bleaching was performed for 50 minutes with 6% HP in three sessions. The absolute risk and intensity of GI were assessed with a visual analogue scale. Color change was assessed using a digital spectrophotometer and color guides. The impact of oral condition on quality of life was assessed using the Brazilian version of the Oral Health Impact Profile (α=0.05).

RESULTS

The proportion of patients who presented GI for the "with barrier" group was 31.6% and for the "without barrier" group, 30% (p=1.0). There is an equivalence for the evaluated groups regarding GI intensity (p<0.01). Color change was detected with no statistical differences (p>0.29). There was a significant impact of oral condition on quality of life after bleaching (p<0.001).

CONCLUSIONS

The use or not of the gingival barrier for in-office bleaching with 6% HP was equivalent for GI, as well as for bleaching efficacy, with improvement in the impact of oral condition on quality of life.

Assessment of color changes and adverse effects of over-the-counter bleaching protocols: a systematic review and network meta-analysis

OBJECTIVES

To assess color change efficacy and the adverse effects of varied over-the-counter (OTC) bleaching protocols.

METHODOLOGY

The study included randomized clinical trials evaluating color changes from OTC bleaching agents. Nine databases were searched, including the partial capture of the grey literature. The RoB2 tool analyzed the individual risk of bias in the studies. Frequentist network meta-analyses compared treatments through common comparators (∆Eab* and ∆SGU color changes, and tooth sensitivity), integrating direct and indirect estimates and using the mean and risk differences as effect measures with respective 95% confidence intervals. The GRADE approach assessed the certainty of the evidence.

RESULTS

Overall, 37 remaining studies constituted the qualitative analysis, and ten composed the meta-analyses. The total sample included 1,932 individuals. ∆Eab* was significantly higher in groups 6% hydrogen peroxide (HP) strips (≥ 14 h). ∆SGU was significantly higher in groups at-home 10% carbamide peroxide (CP) (≥ 14 h), followed by 6% HP strips (≥ 14 h) and 3% HP strips (≥ 14 h). At-home 10% CP (7-13 h) and placebo showed lower risks of tooth sensitivity without significant differences between these treatments.

CONCLUSION

Considering the low level of evidence, OTC products presented satisfactory short-term effects on tooth bleaching compared to the placebo, with little to no impact on dentin hypersensitivity and gingival irritation.

CLINICAL RELEVANCE

OTC products are proving to be practical alternatives for tooth whitening. However, patients should be advised about the possible risks of carrying out such procedures without professional supervision.

Effect of topical application of ibuprofen/arginine on the in-office bleaching-induced tooth sensitivity: A randomized, triple-blind controlled trial

OBJECTIVE

The application of anti-inflammatories as topical desensitizers before dental bleaching is an approach to reduce bleaching-induced tooth sensitivity (TS). This randomized controlled trial compared the risk and intensity of TS and the color change resulting from in-office dental bleaching after using an experimental desensitizing gel containing ibuprofen and arginine.

METHODS

Sixty-two participants with upper canine shades A2 or darker were randomly assigned to either the ibuprofen-arginine desensitizing group or the placebo group. The desensitizing gel was applied for 15 min before in-office bleaching with 35 % hydrogen peroxide gel for 50 min (2 sessions). To assess the absolute risk and intensity of TS, visual (0-10) and numeric rating (0-5) scales were used, and group comparisons were made using the McNemar test, Wilcoxon test, and paired Student t-test (α = 0.05). Color change was evaluated using Vita Classical, Vita Bleachedguide (ΔSGU), and Vita EasyShade (ΔEab, ΔE00, and ΔWID) before and one month after the bleaching procedure. Group comparisons for color change were done using a paired t-test (α = 0.05).

RESULTS

The odds ratio for TS was 0.14 [95 % CI 0.02 to 0.6], meaning lower odds of TS for the desensitizing gel. A lower intensity of TS was also observed for the experimental group (p < 0.005) up to 48 h after bleaching. All color evaluation tools demonstrated effective and similar whitening for both groups (p > 0.05).

CONCLUSIONS

Using the experimental desensitizing gel containing ibuprofen and arginine effectively reduced the risk and intensity of TS without compromising the bleaching efficacy.

CLINICAL RELEVANCE

The topical application of ibuprofen/arginine on the in-office bleaching reduced risk and intensity of bleaching-induced tooth sensitivity.

Potentially carcinogenic effects of hydrogen peroxide for tooth bleaching on the oral mucosa: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Little is known about the extent to which hydrogen peroxide as used for tooth bleaching could be carcinogenic to the oral mucosa.

PURPOSE

The purpose of this systematic review and meta-analysis was to evaluate whether hydrogen peroxide as used for tooth bleaching has carcinogenic effects on the oral mucosa.

MATERIAL AND METHODS

PubMed, Web of Science, Scopus, and Embase electronic databases were searched. Studies evaluating different outcomes potentially related to the carcinogenic effects of hydrogen peroxide for tooth bleaching on the oral mucosa were included. Risk of bias was assessed by the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE), Risk Of Bias in Non-randomized Studies of Interventions (ROBINS-I), or Risk of Bias 2 (RoB 2) tools. The strength of the evidence was assessed by using the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) protocol. The quantitative analysis was performed with means, standard deviations, and 95% confidence intervals (CIs). Heterogeneity was analyzed by using I-squared statistics.

RESULTS

Thirteen articles comprising 5 animal and 8 clinical studies met the inclusion criteria. Three of the 5 animal studies associated the bleaching agents with a carcinogen and demonstrated an enhancement of the carcinogenic effect, but probably with the bleaching agent acting only as a promoter. Five clinical studies concluded that the bleaching agents did not cause mutagenic stress on the oral mucosa by using the micronucleus test. The meta-analysis demonstrated that the frequency of micronuclei did not differ significantly between baseline and 30 days after bleaching (mean difference: 0.48; 95% CI, -1.49, 2.46; P=.63).

CONCLUSIONS

This systematic review indicated that hydrogen peroxide does not appear to have carcinogenic effects on the oral mucosa.

Effect of gingival barrier brands on operator perception, cervical adaptation, and patient comfort during in-office tooth bleaching: a randomized clinical trial

BACKGROUND

Light-cured resins are widely used as gingival barriers to protect the gums from highly concentrated peroxides used in tooth bleaching. The impact of barrier brand on clinical outcomes is typically considered negligible. However, there is limited evidence on the effects of different brands on operator experience, barrier adaptation, and patient comfort.

OBJECTIVE

This clinical trial assessed the impact of four commercial gingival barrier brands (Opaldam, Topdam, Lysadam, and Maxdam) on operator perception, adaptation quality, and patient comfort.

METHODS

Twenty-one undergraduate students placed gingival barriers in a randomized sequence using blinded syringes. Photographs of the barriers were taken from frontal and incisal perspectives. After bleaching procedures, operators rated handling features and safety using Likert scale forms. Two experienced evaluators independently assessed barrier adaptation quality on a scale from 1 (perfect) to 5 (unacceptable). The absolute risk of barrier-induced discomfort was recorded. Data were analyzed using Friedman and Chi-square tests (α = 0.05).

RESULTS

Opaldam and Topdam received the highest scores in most handling features, except for removal, which was similar among all brands. No significant difference was observed in barrier adaptation quality between the evaluated brands. Discomforts were mainly reported in the upper dental arch, with Maxdam having the highest absolute risk (35% for this arch and 24% overall).

CONCLUSIONS

This study suggests that gingival barrier brands can influence operator perception and patient comfort. Opaldam and Topdam were preferred by operators, but all brands demonstrated comparable adaptation quality.

CLINICAL TRIAL REGISTRATION

The study was nested in a randomized clinical trial registered in the Brazilian Clinical Trials Registry under identification number RBR-9gtr9sc.

Microleakage effect of in-office bleaching on two types of nanohybrid composites with or without surface sealer

BACKGROUND

Bleaching is a highly common method used nowadays to treat tooth discolouration because it is a significant cosmetic issue, particularly with anterior teeth, however bleaching itself results in microleakage.

OBJECTIVE

This study aims to evaluate the impact of in-office bleaching on class V restoration microleakage with type 1 and type 2 composite restorations.

METHODS

Three hundred and twenty healthy, caries-free removed human anterior teeth were used in this in-vitro study. All extracted teeth had their buccal and lingual surfaces uniformly prepped for class V cavities. The 120 removed teeth were divided into two groups, with Group 1 receiving Tetric N-Ceram nanohybrid composite restorations and Group 2 receiving 3 M Filtek Z350 XT nanohybrid composite restorations. Groups 1 and 2 were further broken into four more subgroups of four each. The restorations were sealed with a G-Coat Plus resin. The p-value was kept at 0.005 for the data analysis using the Chi-square and Fisher exact tests.

RESULTS

Allocating microleakage among 320 study models revealed that 141 (44.1%) study samples had no microleakage, whereas 20 (6.3%), 54 (16.9%), and 105 (32.8%) study samples had microleakage up to, between, and greater than two-thirds of cavity depth. With a statistically significant p-value of 0.001, no microleakage was discovered in 85 (53.1%) lingual surfaces with Tetric N-Ceram nanohybrid composite restoration and 56 (35%) buccal surfaces with 3M Filtek Z350 XT nanohybrid composite restoration. 19.1% of samples of N-Ceram that were sealed and not bleached had no microleakage, according to analysis of microleakage across several groups. With a p-value of 0.001, the distribution of microleakage among various clusters was statistically notable.

CONCLUSION

According to the findings of the study, hydrogen peroxide bleaching has an enhanced impact on micro escape during dye dispersion. Both with and without bleaching, resin coating can be utilised to minimise marginal microleakage.

[Laboratory evaluation of the effectiveness and safety of the Chairside Light Whitening System fläsh]

THE AIM OF THE STUDY

Optimization of methods for treating dental discoloration using whitening systems based on hydrogen peroxide by laboratory studying their chemical properties.

MATERIAL AND METHODS

The effectiveness of the bleaching system was assessed by quantitatively assessing the color change of model samples of hydroxyapatite (HAP) in the CIE L*a*b* system on a Spectron-M color analyzer after exposure to coloring food media. Safety assessment was carried out on samples made from teeth removed according to indications.

RESULTS

The results of laboratory tests allow us to conclude that the Chairside Light Whitening System professional teeth whitening system fläsh. (WHITEsmile GmbH, Germany) has high whitening efficiency with a whitening degree of ~84%, which significantly exceeds the norm of GOST R 702.3.004-2021. the microhardness of the enamel of samples exposed to the whitening gel for 15 minutes changes extremely little. After exposure of the studied samples to the Chairside Light Whitening System fläsh whitening system for 45 minutes, an increase in digital microhardness indicators is observed, which indicates the dynamics of processes demineralizing the hard tooth structure.

CONCLUSIONS

Chairside Light Whitening System fläsh professional teeth whitening system has high whitening efficiency with minimal impact on the teeth structure and high safety.

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.

Influence of bleaching gels formulated with nano-sized sodium trimetaphosphate and fluoride on the physicochemical, mechanical, and morphological properties of dental enamel

OBJECTIVES

To evaluate in vitro the effects of sodium fluoride (F) and nano-sized sodium trimetaphosphate (TMPnano) added to a 35% hydrogen peroxide (H2O2) bleaching gel on the color alteration, enamel mechanical and morphological properties, and H2O2 transamelodentinal diffusion.

MATERIALS AND METHODS

Bovine enamel/dentin discs (n = 180) were divided according to the bleaching gel: 35% H2O2 (HP); 35% H2O2 + 0.1% F (HP/F); 35% H2O2 + 1% TMPnano (HP/TMPnano); 35% H2O2 + 0.1% F + 1% TMPnano (HP/F/TMPnano) and 35% H2O2 + 2% calcium gluconate (HP/Ca). The gels were applied 3 times by 40 min; once each 7-day. The Commission Internationale de l'Eclairage (CIE) L*a*b* total color alteration (ΔE), color alteration by CIEDE2000 (ΔE00), whitening index (ΔWID), surface (SH) and cross-sectional hardness (ΔKHN), surface roughness (Ra), and transamelodentinal diffusion were determined. Enamel surfaces were evaluated by Scanning Electron Microscopy (SEM) and X-ray Dispersive Energy (EDX). Data were submitted to ANOVA, followed by the Student-Newman-Keuls test (p <0.05).

RESULTS

ΔE, ΔE00, and ΔWID were similar among the gels that promoted a bleaching effect after treatment (p <0.001). Mineral loss (SH and ΔKHN), Ra, and H2O2 diffusion were lower for HP/F/TMPnano; the HP and HP/Ca groups presented the highest values (p <0.001). For SEM/EDX, surface changes were observed in all bleached groups, but less intense with TMPnano.

CONCLUSIONS

Gels containing F/TMPnano do not interfere with the bleaching effect and reduce enamel demineralization, roughness, H2O2 diffusion, and morphological changes.

CLINICAL RELEVANCE

Whitening gels containing F/TMPnano can be used as a new strategy to increase safety and maintain clinical performance.

Effect of a Toothpaste for Sensitive Teeth on the Sensitivity and Effectiveness of In-office Dental Bleaching: A Randomized Clinical Trial

OBJECTIVES

The present study aimed to evaluate the desensitizing effect of toothpaste for sensitive teeth on patient tooth sensitivity and on bleaching efficacy of the 38% hydrogen peroxide bleaching agent used for in-office bleaching compared to a regular toothpaste in a randomized clinical trial.

METHODS AND MATERIALS

Forty-eight patients having maxillary right central incisors with darkness greater than A1 were selected for the present double-blind randomized clinical trial. Patients were randomly allocated into two groups: the placebo group, which used regular toothpaste, and the experimental group, which used sensitivity toothpaste. The intervention consisted of applying toothpaste with the aid of an individual tray for a period of 4 minutes daily, starting one week before the first bleaching session and interrupting use immediately after the second session. After allocation to one of the groups, individuals received in-office dental bleaching with a 40-minute application of 38% hydrogen peroxide for two sessions with an interval of one week. The incidence and intensity of sensitivity were assessed using a visual analogue scale and a numeric analogue scale. Sensitivity was measured immediately before each session, 1 hour, 24 hours, and 48 hours after each bleaching session and four weeks after the second bleaching session. Tooth shade was evaluated using a spectrophotometer and by comparison with the VITA Classical Shade Guide (Vita Zahnfabrik, Bad Säckingen, Germany). Tooth shade was evaluated before the first bleaching session, one week after the first bleaching session, one week after the second bleaching session and four weeks after the second bleaching session. Participants and professionals who performed the bleaching, shade, and sensitivity assessments were blinded to the group of patients they were treating or assessing. For the incidence of hypersensitivity, the results were evaluated by comparing the groups at different evaluation times with the Mann-Whitney test for comparison between groups, the Friedman test for repeated measures, and the Tukey test for comparison of times. Shade change on the guide was analyzed using the Mann-Whitney test for comparison between groups and the Wilcoxon test for comparison between times. Shade change by the spectrophotometer was analyzed using the t-test for comparison between groups and the paired t-test for comparison between times. All analyses were performed with a significance level of 5%.

RESULTS

There was no difference in the pattern of dental hypersensitivity between groups. For all shade measures, there was no difference between the bleaching results, and no statistically significant difference was observed between the study groups.

CONCLUSION

The use of arginine-based desensitizing toothpaste did not interfere with the bleaching ability of hydrogen peroxide and was not effective in reducing the sensitivity caused by in-office tooth bleaching.

Effect of Tooth Bleach on Dentin Fatigue Resistance in Situ

BACKGROUND

Negative effects of bleaching on dentin have previously been reported in vitro.

OBJECTIVE

The purpose of this study was to determine the effect of carbamide peroxide bleaching on dentin fatigue resistance using a clinically relevant in situ model.

METHODS AND MATERIALS

Following research ethics board approval, 60 human teeth requiring extraction were collected. Sterilized human dentin specimens were cut (1.2x1.2x10 mm) and secured into customized bleaching trays to be used by study participants. Participants were randomly assigned to either bleach (10% carbamide peroxide, n=23) or control (gel without bleach, n=26) treatment groups. Treatment was applied to the bleaching trays and worn overnight by participants for 14 days. After treatment completion, dentin specimens were removed from the bleaching trays and subjected to fatigue testing (10 N, 3 mm/s, 2x105 cycles) while submerged in artificial saliva. Kaplan-Meier survival analysis was conducted to compare the number of cycles to failure during fatigue testing in both groups. A log rank test was run to determine if there were differences in the survival distribution between the two groups (α<0.05).

RESULTS

The median number of cycles to failure was 352 ± 202 and 760 ± 644 for the bleach and control groups, respectively. The survival distributions for the two groups were significantly different (p=0.020). Dentin fatigue resistance was significantly lower in the bleach group compared to the control.

CONCLUSIONS

Direct bleaching of human dentin using an at-home tray bleaching protocol in situ reduced dentin fatigue resistance. This has implications for tooth fracture risk and longevity.

The Effect of Calcium Silicate-Based Materials on Tooth Discoloration and Evaluation of Color Change After Bleaching Treatment: A Spectrophotometric Study

PURPOSE

To evaluate tooth discoloration after the use of calcium silicate-based materials and to examine the effect of internal bleaching on tooth discoloration.

MATERIALS AND METHODS

The specimens were randomly divided into two experimental groups (n = 45) and a control group (n = 6). Cavities were filled with ProRoot MTA (Dentsply) in Group 1 and Biodentine (Septodont) in Group 2. Color measurements were taken with a spectrophotometer before and after the application of materials at 1 week and then at 13, and 6 months. After 6 months, Groups 1 and 2 were divided into three subgroups according to internal bleaching techniques. All color change ratios and lightness differences were calculated using the CIE L*a*b* system. Data were analyzed using repeated ANOVA and the Kruskal-Wallis test (P = .05).

RESULTS

There were statistically significant differences between Groups 1 and 2 at all time intervals (P < .05). Group 1 showed more discoloration than Group 2 (P < .05). There were no significant differences between the bleaching agents (P > .05). Additionally, specimens in both groups became lighter than their initial color (P < .05).

CONCLUSION

Teeth treated with ProRoot MTA exhibited darkening at 1 week that increased over time, whereas those treated with Biodentine maintained the lightness for 6 months.

Effect of bleaching treatments on the adhesion of orthodontic brackets: a systematic review

BACKGROUND

Nowadays bleaching procedures have gained popularity in orthodontic patients. Peroxide and Carbamide acids are the common agents which are used in in-office and at home bleaching techniques. Consequently, the Bonding adhesion to the enamel can be influenced by the orthodontic phase and the residual peroxide might interfere with the polymerization and the adhesion of the brackets. Frequent debonding of the brackets from teeth after the bleaching procedure could cause the lengthening of the therapy and promote irregularities on enamel surface derived from an additional bonding phase of the brackets. The aim of this systematic review is to appraise the influence regarding the effect of the bleaching procedure on the bond strength of orthodontic brackets.

METHODS

An electronic database search was performed. Search terms included: bleaching, brackets, adhesion; data were extracted and summarized. Risk of bias was assessed using the Chocrane risk of bias tool, adapted for in vitro studies.

RESULTS

A total of 8689 articles were screened and 11 studies met the inclusion criteria of this systematic review. 1000 teeth of human and bovine origin were analyzed for the shear bond strength (SBS) of stainless and ceramic brackets after the bleaching treatments. All the authors divided the groups in different subgroups with different bleaching agents and in different concentration. The SBS value allowed to demonstrate the necessity to delay the bonding of the brackets for two weeks after a bleaching treatment and its improvement when tooth mousse or antioxidants agents are used.

CONCLUSIONS

The SBS values and the delay of the bonding procedure must be considered in dental practice and clinical strategies are necessary in order to avoid drawbacks which could cause the debonding of the brackets after bleaching due to the alterations of the dental substrate, thus interfering with the orthodontic treatments.

Temperature changes in the pulp chamber and bleaching gel during tooth bleaching assisted by diode laser (445 nm) using different power settings

The aim of this in vitro study was to investigate the safety of using blue diode laser (445 nm) for tooth bleaching with regard to intrapulpal temperature increase operating at different average power and time settings. Fifty human mandibular incisors (n = 10) were used for evaluating temperature rise inside the pulp chamber and in the bleaching gel during laser-assisted tooth bleaching. The change in temperature was recorded using K thermocouples for the five experimental groups (without laser, 0.5, 1, 1.5 and 2 W) at each point of time (0, 10, 20, 30, 40, 50 and 60 s). As the average power of the diode laser increases, the temperature inside the pulp chamber also increases and that of the bleaching gel was significantly higher in all the experimental groups (p < 0.05). However, the intrapulpal temperature rise was below the threshold for irreversible thermal damage of the pulp (5.6 °C). Average power of a diode laser (445 nm) ranging between 0.5-2 W and irradiation time between 10-60 s should be considered safe regarding the pulp health when a red-colored bleaching gel is used. Clinical studies should confirm the safety and effectiveness of such tooth bleaching treatments. The outcomes of the present study could be a useful guide for dental clinicians, who utilize diode lasers (445 nm) for in-office tooth bleaching treatments in order to select appropriate power parameters and duration of laser irradiation without jeopardizing the safety of the pulp.

The effect of propolis on the bond strength of composite resin to enamel after intracoronal bleaching with different bleaching agents

This study evaluated the effect of propolis as an antioxidant agent on bond strength to enamel after intracoronal bleaching. A total of 160 incisors were endodontically treated. Sixteen teeth were served as control, and the remaining teeth were randomly divided into three main groups according to the bleaching agent used; group 1: Sodium perborate (SP); group 2: Carbamide peroxide (CP); group 3: Hydrogen peroxide (HP). After bleaching, the samples were divided into three subgroups; subgroup A: no antioxidant agent application, subgroup B: sodium ascorbate (SA), subgroup C: propolis (PP). After the antioxidant agents application, the sample's surfaces were washed and dried. After adhesive application, composite resin cylinders were applied to enamel surfaces using tygon tubes and a shear bond strength test was performed. The use of PP significantly decreased the bond strength of composite resin to the enamel (p < 0.05). Using propolis as an antioxidant agent adversely affects the bond strength to enamel after intracoronal bleaching.

[Effect of bleaching combined with Er:YAG or Nd:YAG laser on shear bond strength and microleakage of resin restoration]

PURPOSE

To evaluate the effects of bleaching combined with Er:YAG laser or Nd:YAG laser on bond strength and microleakage of resin fillings on enamel surface.

METHODS

Sixty-four pieces of enamel specimens prepared from isolated teeth were randomly divided into 4 groups(n=16): control group, simple bleaching group, bleaching combined with Er: YAG laser group and bleaching combined with Nd:YAG laser group. Then the shear bond strength and the depth of microleakage were tested, and the fracture mode of the specimen was observed under microscope. SPSS 26.0 software package was used for statistical analysis.

RESULTS

After bleaching simply, the bond strength of the restoration was significantly decreased, and the marginal microleakage was significantly increased(P＜0.05). There was no significant difference in shear bond strength and microleakage depth between the group bleaching combined with Er: YAG laser and control group(P＞0.05). The shear bond strength after bleaching combined with Nd:YAG laser was significantly reduced (P＜0.05), but there was no significant difference in the depth of microleakage compared with unbleached microleakage(P＞0.05). Bonding interface fracture was the main fracture mode for all groups.

CONCLUSIONS

Compared to traditional bleaching, bleaching combined with laser has certain clinical advantages due to its less influence on bond strength and microleakage of resin fillings.

Susceptibility to discoloration of dental restorative materials containing dimethacrylate resin after bleaching

The aim of this study is to compare the susceptibility to discoloration of dental restorative materials containing dimethacrylate resin after bleaching. In this study, resin-modified glass ionomer, polyacid-modified composite resin, giomer, posterior composite resin, anterior composite resin, bulk fill composite resin, flowable bulk fill composite resin, ormocer, indirect composite resin and hybrid ceramics were used as restorative material containing dimethacrylate resin. 20 samples were prepared from each material in accordance with the manufacturer's instructions. After the baseline colors are measured, the samples were randomly divided into four subgroups as office bleaching, home bleaching and a separate control group for each type bleaching method. Then, the samples were bleached and colored. Color measurements of the samples were repeated after exposure to bleaching and coloring. Then, ΔE00 and whiteness index (WID) were calculated. Data were analyzed using Paired-Samples T Test, two-way ANOVA, Repeated Measures ANOVA and Tukey post-hoc tests. Statistical significance level was taken as p < 0.05. In terms of bleaching systems, Opalescence Boost was found to cause more whitening in materials but more discoloration (p < 0.05). In terms of materials, it was found that the most susceptible materials to coloration were Clearfil Majesty Posterior, Filtek Bulk Fill Posterior Restorative, Filtek Bulk Fill Flowable and Fuji II LC, while the least susceptible materials were CAD/CAM materials (p < 0.05). The bleaching process increases the susceptibility to coloration of materials containing dimethacrylate resin.

Effectiveness and Safety of Over-the-Counter Tooth-Whitening Agents Compared to Hydrogen Peroxide In Vitro

(1) This study investigated the whitening effect, cytotoxicity and enamel surface alterations induced by different over-the-counter (OTC) bleaching agents in comparison to hydrogen peroxide. (2) Human teeth (n = 60) were randomly assigned into 6 groups (n = 10), stained with coffee solution for 7 d, followed by a whitening period of 7 d with either placebo, bromelain, sodium bicarbonate, sodium chlorite, PAP or hydrogen peroxide. Color measurements were performed with a spectrophotometer. Scanning electron micrographs (SEM) were taken to assess the enamel structure. Cytotoxicity of the tested substances was assessed based on the cell viability of primary human fibroblasts. (3) The application of all whitening gels resulted in a greater color difference of the enamel (ΔE) in comparison to the negative control. Hydrogen peroxide caused the greatest color difference. Bromelain and PAP treatment showed no enamel surface changes, in contrast to hydrogen peroxide treatment, which showed very mild interprismatic dissolution. Bromelain was the only non-cytotoxic agent. (4) The maximum effect achieved by all OTC bleaching agents was the removal of stains, whereas hydrogen peroxide was capable of further whitening the teeth. Bromelain treatment was neither cytotoxic, nor resulted in enamel surface alterations, and its whitening effect was less, yet still effective, compared to hydrogen peroxide.

Use of infrared photobiomodulation with low-level laser therapy for reduction of bleaching-induced tooth sensitivity after in-office bleaching: a double-blind, randomized controlled trial

The purpose of this study is to evaluate the use of infrared photobiomodulation with low-level laser therapy (PBM) to reduce bleaching-induced tooth sensitivity (TS) after in-office bleaching. Eighty-three participants were randomized in blocks into two groups. In the experimental group, the patients received an application after each session of in-office bleaching (35% hydrogen peroxide, 1 × 50 min; 2 sessions with 1-week interval), while the laser application was simulated in the control group. The PBM system was operated in continuous mode, using 3 J of energy. A dose of 100 J/cm2 was applied for 30 s with 808 nm (100 mW of power) in the middle third of the crown. The risk and intensity of TS were recorded immediately after bleaching, 1 h, 24 h, and 48 h after each bleaching session, with a visual scale analog (0-10) and a five-point numerical scale (0-4). The color was recorded at the beginning, weekly, and 1 month after the end of the bleaching (VITA Classical, VITA Bleachedguide, and digital spectrophotometer). The risk of TS was 98% (95% CI 88 to 99%) for the laser group and 95% (95% CI 83 to 99%) for the control (RR = 1.03; 95% CI 0.94 to 1.12; p = 1.0). Similarly, no difference in the intensity of TS was detected for both pain scales (p > 0.65). Improvement in color change, regardless of the group, was observed (p > 0.15). The application of an PBM did not reduce the risk and intensity of TS when applied after the procedure using the parameters recommended by the manufacturer.Trial registration number and date of registration: RBR-4HCVSG-04/06/2019.

Clinical Testing of Walking Bleach, In-Office, and Combined Bleaching of Endodontically Treated Teeth

Objective. The causes of internal posteruptive discoloration of teeth are bleeding, necroses, infections, and endodontic filling materials. The aim of this study was to establish the results of bleaching endodontically treated teeth using walking bleach, in-office, and combined techniques, using 30% carbamide peroxide and 35% hydrogen peroxide, as well as the effect of etiological factors, and the time elapsed after endodontic treatment on the success of bleaching. Materials and Methods. The research involved 30 endodontically treated teeth in healthy patients. Retroalveolar X-rays were taken to check the quality of root canal obturation. Endodontic treatment and obturation were carried out on the discolored non-vital teeth without any previous endodontic treatment. Before bleaching, two millimeters of the filling were removed from the root canal and the very entry into the canal was protected with glass ionomer cement. The teeth were divided into three groups, depending on the bleaching technique: walking bleach technique (10 patients), in-office technique (10 patients), and combined technique (10 patients). The teeth were bleached with 30% carbamide peroxide and 35% hydrogen peroxide. The bleaching procedure was repeated in all the patients three times. The color of all teeth was determined based on the Vita Classic guide before and after bleaching. The Χ2 square and Kruskal−Wallis tests were used to identify differences in teeth bleaching results. Results. A statistically significant difference (p < 0.05) was established between bleaching success and the time elapsed after endodontic treatment. There were no statistically significant differences observed between the bleaching success and etiological factors, bleaching techniques, or bleaching agents. Conclusions. The effectiveness of non-vital tooth bleaching is affected by the time elapsed after endodontic treatment.

Effect of high-concentration bleaching agents on dentin bonding: an in vitro study

The aim of this in vitro study was to evaluate the effect of high-concentration hydrogen peroxide (HP) and carbamide peroxide (CP) bleaching solutions on the dentin-resin interface and the shear bond strength (SBS) of restorative materials. A total of 56 extracted human premolars were prepared with flat dentin windows and divided into groups according to the bleaching protocol: group A, bleached with 35% HP (n = 24); group B, bleached with 35% CP (n = 24); and group C, control, no bleaching (n = 8). Groups A and B were each divided into 3 subgroups according to the time of bonding: A0 or B0, bonded immediately after bleaching (n = 8); A1 or B1, bonded 1 week after bleaching (n = 8); and A2 or B2, bonded 2 weeks after bleaching (n = 8). The specimens in group C were bonded without prior bleaching. Scanning electron microscopic analysis was conducted to evaluate the length of the resin tags at the dentin-resin interface. For SBS testing, the specimens were loaded into a universal testing machine at a crosshead speed of 0.5 mm/min. The mean resin tag lengths of groups that were bonded immediately (A0 and B0) or after a 1-week delay (A1 and B1) were significantly shorter than that of group C (P < 0.001; Kruskal-Wallis test), but the differences between the 2-week delayed bonding groups (A2 and B2) and group C were not statistically significant. The SBS values of both the 35% HP and 35% CP groups increased significantly with delayed bonding time (P < 0.05; 1-way analysis of variance). When bonding was delayed until 2 weeks after bleaching, the mean SBSs of the bleaching and control groups were not significantly different (P > 0.05; Tukey test).

In vitro safety evaluation of a hydrogen peroxide whitening emulsion technology on human enamel and dentin

PURPOSE

To assess effects of a novel hydrogen peroxide leave-on whitening emulsion on surface hardness, fracture susceptibility, surface erosion, and surface morphology of enamel and dentin.

METHODS

Human enamel and root dentin sections embedded in resin were leveled and polished for uniformity. A cycling treatment simulating overuse conditions (60 hours over 10 days), coupled with incubation in pooled human saliva at 37°C and two daily toothpaste treatments were used to evaluate the safety of a 3% hydrogen peroxide whitening emulsion treatment (Crest Whitening Emulsions). Controls included a no treatment group, three erosion controls (water, 0.25% citric acid pH 3.6, 1% citric acid pH 3.6), and a bleaching control (8.25% sodium hypochlorite). Color measurements (b*) were taken on select post-treated specimens to confirm bleaching activity. Effects on enamel and dentin physical properties were determined by surface microhardness, fracture toughness, erosion depth, and surface morphology by light and scanning electron microscopy.

RESULTS

The hydrogen peroxide emulsion b* value was significantly different versus water control (P< 0.05), confirming bleaching activity. Microhardness and fracture toughness results for hydrogen peroxide emulsions were not significantly different versus baseline (P> 0.2) and no treatment (P= 1.0), respectively. Erosion loss for the hydrogen peroxide emulsion was not observed on enamel (comparable to water) and significantly less than 0.25% citric acid (P< 0.05) on dentin which was verified by microscopic visualization.

CLINICAL SIGNIFICANCE

The hydrogen peroxide emulsion had no significant negative effects on enamel and dentin properties after 60 hours of bleaching over 10 days, confirming safety under simulated overuse conditions.

[Effect of penetrating resin on the surface structure, microhardness and color of enamel after bleaching]

Objective: To investigate the effect of permeable resin on the surface structure, microhardness and color of tooth enamel after bleaching. Methods: Premolars extracted for orthodontic needs were selected (provided by the Department of Oral and Maxillofacial surgery of the first affiliated Hospital of Zhengzhou University) and randomly divided into A, B and C 3 groups. Each group was randomly divided into control subgroup, resin subgroup, bleaching subgroup and combined subgroup. Samples in the control subgroup did not receive any treatment. Those in the bleaching subgroup and combined subgroup were treated with cold light whitening. Those in the resin group and combined group were treated with permeable resin. Samples in the group A were observed by scanning electron microscope immediately after treatment and 2 weeks after treatment, and the microhardness of samples in the group B was measured before treatment, immediately after treatment and 2 weeks after treatment (the sample size of each time point was 8 in each subgroup). In group C, chromaticity was measured and chromatic aberration (ΔE value) was calculated before treatment, immediately after treatment and 1 and 2 weeks after treatment (10 samples in each subgroup). Results: Scanning electron microscope showed that the enamel surface of the resin subgroup and the combined group was smooth immediately after treatment, which was basically the same as that of the control subgroup, but covered with resin, and microporous defects and mineral deposits could be seen on the surface of the bleaching subgroup. Two weeks after treatment, the enamel surface of each subgroup was smooth, there was no obvious difference. Immediately after treatment, the microhardness of the control subgroup, resin subgroup, bleaching subgroup and combined subgroup were (354±33), (364±21), (411±30) and (350±17) HV, respectively (F=9.39,P<0.05). The microhardness of the bleaching subgroup was significantly higher than that of the other subgroups (P<0.05). There was no significant difference in microhardness among the four subgroups before treatment and 2 weeks after treatment (F=0.34, 2.75, P>0.05). Immediately after treatment, the ΔE values of the control subgroup, resin subgroup, bleaching subgroup and combined subgroup were 0.00±0.00, 2.29±1.86, 7.20±1.94 and 8.00±0.88, respectively (F=74.21,P<0.05); except that there was no significant difference between bleaching subgroup and combined subgroup (P>0.05), there were significant differences among the other subgroups (P<0.05). There was no significant difference in ΔE value among control subgroup, resin subgroup and bleaching subgroup at each time point (F=1.66, 0.30, 0.96, P>0.05). The difference in the combined subgroup immediately after treatment was significantly higher than that at 1 and 2 weeks after treatment (t=4.73, 4.23,P<0.05), but there was no significant difference between 1 and 2 weeks after treatment (t=0.75, P>0.05), and the color tended to be stable. Conclusions: When whitening healthy enamel, simple cold light whitening or cold light whitening combined with permeation resin can achieve whitening effect.

Various Aspects Involved in the Study of Tooth Bleaching Procedure: A Questionnaire–Based Study

A beautiful smile is an important feature when it comes to a pleasant appearance of the face, and one of the most common situations that drive patients to book a dental appointment is tooth discoloration. Tooth bleaching is the treatment of choice for extrinsic tooth discoloration, as it is a cheap, fast, and minimally invasive procedure. This study aimed to provide comparative information on the perceptions of both patients and dentists regarding different whitening methods and on the factors involved in people’s willingness to recommend and use a bleaching procedure. In addition to this, this study evaluated the degree of satisfaction in relation to the bleaching methods and materials used; it also evaluated the following: negative side effects, economic characteristics and the patients’ perceptions of the aesthetic appearance of their dental arches, especially tooth color. The subjects that participated in the present study were selected based on their background and were then divided into two categories. The first group consisted of 120 patients who had received tooth-bleaching treatments in dental clinics during the study and the second group consisted of 127 dentists. A conventional sampling method was used. The study aimed to define a relationship between multiple aspects of the tooth-bleaching procedure, including the patients’ desires and their general knowledge of this procedure. Tooth color and the way it changes is a very important factor that motivates patients to come to the dentist for whitening procedures. Patients showed the highest levels of satisfaction with the results of in-office bleaching procedures. In the group consisting of dentists, satisfaction levels were higher for the procedure of home bleaching supervised by a dentist. Factors influencing the choice of bleaching materials are appreciated differently by dentists and patients. Furthermore, the rate of patients using OTC (over the counter) products was found to be high. Further research is needed to find more effective and safer alternatives to home tooth-bleaching procedures.

Does the Bleaching Gel Application Site Interfere With the Whitening Result? A Randomized Clinical Trial

This study aimed to evaluate the effect of the bleaching gel application site on chromatic changes and postoperative sensitivity in teeth. Thirty patients were selected and allocated to three groups (n=10 per group), according to the location of the gel: GI, cervical application; GII, incisal application; and GIII, total facial. The amount and time of application of the 35% hydrogen peroxide (H2O2) gel were standardized. Color changes were analyzed by ΔE and Wid (bleaching index), using the values obtained in the readings conducted on a digital spectrophotometer in the cervical (CRs) and incisal regions (IRs) of the teeth. Spontaneous sensitivity was assessed using the questionnaire, and the stimulated sensitivity caused by the thermosensory analysis (TSA). The analysis occurred in five stages: baseline, after the first, second, and third whitening sessions (S), and 14 days after the end of the whitening, using the linear regression statistical model with mixed effects and post-test by orthogonal contrasts (p<0.05). Although the IR was momentarily favored, at the end of the treatment, the restriction of the application site provided results similar to those obtained when the gel was applied over the entire facial surface. Regarding sensitivity, only the GI showed spontaneous sensitivity. In the TSA, GIII had less influence on the threshold of the thermal sensation. It was concluded that the chromatic alteration does not depend on the gel application site. Spontaneous sensitivity is greater when the gel is concentrated in the cervical region (CR), and the teeth remain sensitized by thermal stimuli even after 14 days.

Historical Reflections on the Use of Internal Bleaching to Manage Discolored Teeth

The process of internal bleaching of discolored teeth has been with us for well over 150 years, during which time both materials and procedures varied significantly. The etiology of tooth discoloration also reflected on a wide range of philosophies and causes, which lent itself to many trials and errors in management. Both success and failure characterized the achievements attained by our forefathers in managing this esthetic challenge, as years ago tooth extraction was often the first pathway chosen.

In-office bleaching with complete cervical third protection protocol: A split-mouth, double-blind, randomized clinical trial

PURPOSE

To evaluate the bleaching sensitivity and the bleaching effectiveness of in-office bleaching, following a protocol of complete cervical third protection with gingival dam in comparison with a traditional manner of applying gingival dam (used only in the gingival sulcus area).

METHODS

35 participants were selected for this double-blind split-mouth randomized clinical trial. The control group received the gingival barrier in the traditional manner, and in the experimental group the barrier was extended by about 3 mm to include the cervical region. The bleaching agent was applied in two sessions. The risk and intensity of bleaching sensitivity were assessed using two scales. The bleaching effectiveness was evaluated with a digital spectrophotometer with the tip placed in the cervical area. The absolute risk of bleaching sensitivity was compared by the McNemar's test and bleaching effectiveness (ΔEab, ΔE00 and ΔWi) and intensity of bleaching sensitivity was evaluated by Wilcoxon-paired test (α= 0.05).

RESULTS

No significant difference at risk (P= 1.0) and intensity of bleaching sensitivity (P> 0.45) was seen between groups. After 30 days, bleaching effectiveness had no statistical difference between the groups (P> 0.09).

CLINICAL SIGNIFICANCE

Extending the barrier in the cervical region of teeth did not reduce the risk and intensity of bleaching sensitivity, nor jeopardize the bleaching effectiveness.

Clinical effects of the exposure to red wine during at-home bleaching

OBJECTIVES

This clinical trial evaluated the effects of red wine exposure on the effectiveness of at-home bleaching with 10% carbamide peroxide, degree of tooth sensitivity, and levels of periodontal inflammatory markers.

METHOD AND MATERIALS

Eighty participants were assigned to two groups, namely, those who drank red wine (experimental group), and those who did not drink red wine (control group). The experimental group participants rinsed their mouths with 25 mL of red wine four times a day during the bleaching period. Shade evaluation was assessed visually by using the Vita Classical and Vita Easyshade techniques. Tooth sensitivity was evaluated by the numeric and visual analog scales, and the salivary and gingival crevicular fluids were collected for assessment of nitric oxide (NO) levels, a marker of inflammation. Differences in color change were analyzed by one-way analysis of variance (ANOVA). The absolute risks of tooth sensitivity were compared by the Fisher exact test. Tooth sensitivity intensity data sets for both the visual analog scale and the numeric rating scale were compared using the Wilcoxon signed rank test (α = .05). Repeated measures and two-way ANOVA followed by the Bonferroni test were used to assess time-course and differences between groups in NO production.

RESULTS

The bleaching technique was effective regardless of wine consumption (P > .05). Tooth sensitivity was classified as mild, with no differences between groups (P > .05). Red wine reduced both the gingival crevicular fluid and salivary levels of NO (P < .05).

CONCLUSION

Red wine does not interfere with the effectiveness and sensitivity of at-home teeth bleaching with 10% carbamide peroxide and protects against bleaching-induced inflammation.

Effect of Daily Usage Time of 4% Hydrogen Peroxide on the Efficacy and Bleaching-induced Tooth Sensitivity: A Single-blind Randomized Clinical Trial

OBJECTIVE

Compare the risk/intensity of tooth sensitivity (TS) and color change of a 30-minute vs. the recommended 120-minute application time of 4% hydrogen peroxide (HP) for at-home bleaching.

METHODS

A single-blind, parallel, randomized clinical trial was conducted with 92 adult patients with caries and restoration-free anterior teeth A2 or darker, randomly allocated to two groups. Bleaching trays containing 4% HP were used for three-weeks. A four-week regimen was also offered to the patients for the 30-min group after the end of the 3-week protocol. The color change was assessed with the Vita Classical (VITA Zahnfabrik, Bad Säckingen, Germany) and Vita Bleachedguide shade guides (VITA Zahnfabrik) and the Vita Easyshade spectrophotometer (VITA Zahnfabrik) at baseline, weekly, and 30 days after the bleaching. The absolute risk and the intensity of TS were assessed daily using the 0-10 visual analogue scale (VAS) and 5-point Numerical Rating Scale (NRS) scale, and patient satisfaction was recorded with a Likert 0-7 scale. Risk of TS (Fisher's test), intensity of TS in NRS scale (Mann-Whitney test), VAS scale (t-test), and a color change (t-test) were compared.

RESULTS

The 30-minute group saw color change of around 1 SGU inferior to the 120-minute group in all-time assessments (p<0.05). After an extra week of bleaching, mean color change was similar (p>0.05). Patient satisfaction was high for both groups (p>0.05).

CONCLUSIONS

A four-week protocol of at-home dental bleaching with 4% HP for 30 minutes/day whitened teeth similarly to the 120 minutes/day protocol, with low intensity of dental sensitivity and high patient satisfaction.

The effect of sodium hexametaphosphate on sensitivity and whitening effectiveness of an at-home bleaching gel: a randomized, triple-blinded clinical trial

OBJECTIVE

Bleaching sensitivity (BS) is the most common adverse effect of tooth bleaching treatments. This study evaluated the effect of adding 1% sodium hexametaphosphate (SHMP) on BS and the whitening effectiveness of a bleaching gel.

METHOD AND MATERIALS

Two maxillary quadrants from 26 patients were randomly assigned to the experimental and control groups in a split-mouth design. In the control group the at-home bleaching gel containing 3% hydrogen peroxide, and in the experimental quadrant the same gel with 1% SHMP, were applied in individual trays for 6 hours per night for 2 weeks. The patients' sensitivity to cold and touch as well as spontaneous sensitivity were recorded based on a visual analog scale (VAS). Changes in shade guide units (ΔSGU) and ΔE were measured using a spectrophotometer. Data were analyzed using the Kolmogorov-Smirnov, Mann-Whitney U, Wilcoxon signed-rank test, and independent sample t test.

RESULTS

Twenty-four patients completed the study. After 2 weeks, the sensitivity to cold and touch was significantly lower in the intervention group compared to the control (P = .015 and P = .039, respectively). The spontaneous sensitivity revealed no significant alteration between these two groups and during the bleaching period in each group (P > .050). Regarding both color measurements, the bleaching effectiveness in both groups was comparable, with no noticeable difference (P > .050).

CONCLUSION

The application of 1% SHMP was able to reduce the BS with no detrimental effect on the at-home bleaching effectiveness. (Quintessence Int 2021;52:596-605; doi: 10.3290/j.qi.b1098303).

Laser Influence on Dental Sensitivity Compared to Other Light Sources Used During In-office Dental Bleaching: Systematic Review and Meta-analysis

CLINICAL RELEVANCE

The use of laser light during bleaching will not reduce the incidence or severity of sensitivity and will not increase the degree of color change compared with nonlaser light sources.

SUMMARY

Objective: To evaluate whether the use of laser during in-office bleaching promotes a reduction in dental sensitivity after bleaching compared with other light sources.Methods: The present review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and is registered with PROSPERO (CDR42018096591). Searches were conducted in the PubMed/Medline, Web of Science, and Cochrane Library databases for relevant articles published up to August 2018. Only randomized clinical trials among adults that compared the use of laser during in-office whitening and other light sources were considered eligible.Results: After analysis of the texts retrieved during the database search, six articles met the eligibility criteria and were selected for the present review. For the outcome dental sensitivity, no significant difference was found favoring any type of light either for intensity (mean difference [MD]: -1.60; confidence interval [CI]: -3.42 to 0.22; p=0.09) or incidence (MD: 1.00; CI: 0.755 to 1.33; p=1.00). Regarding change in tooth color, no significant differences were found between the use of the laser and other light sources (MD: -2.22; CI: -6.36 to 1.93; p=0.29).Conclusions: Within the limitations of the present study, laser exerts no influence on tooth sensitivity compared with other light sources when used during in-office bleaching. The included studies demonstrated that laser use during in-office bleaching may have no influence on tooth color change.

The effect of laser-activated bleaching with 445 nm and 915 nm diode lasers on enamel micro-hardness; an in vitro study

BACKGROUND

The appearance of the teeth is of great importance to patients, particularly tooth color. In recent years, tooth whitening has been one of the most popular ways to restore tooth color. Bleaching gels can be affected by heat, light or laser, which can improve its effects. This study intends to examine the effects of two different wavelengths of diode laser (445 & 915 nm) after the bleaching process, on the enamel micro-hardness.

METHODS

A total of 65 caries-free humans third molars were randomly divided into five groups (N = 13): first group: bleaching gel activated with 915 nm diode laser (1.5 W), second: bleaching gel activated with 915-nm (2.5 W), third: bleaching gel activated with 445-nm (1 W), fourth: bleaching gel activated with 445-nm (1.5 W), fifth (control group): bleaching gel without laser activation. Micro-hardness test (Vickers test) was performed before and after the treatment. The data were submitted to repeated measurement ANOVA and Tukey's HSD post hoc test (α = 0.05).

RESULTS

Enamel micro-hardness did not change significantly in groups 3 and 4 but decreased in groups 1 and 2. Group 2 showed the most reduction in micro-hardness. There were no significant changes in the control group.

CONCLUSION

According to the results of this study, 445 nm Diode laser did not reduce enamel micro-hardness, making it suitable for bleaching treatments. However, more studies are required to consider other factors, such as color changes and pulp temperature.

Home-based chemically induced whitening (bleaching) of teeth in adults: A summary of a systematic review

The demand for whiter teeth has been increasing, and home-based remedies are a popular way of whitening the teeth. These products may be prescribed by the dentist or purchased over the counter and comprise different modes to whiten the teeth and are administered in a range of ways by the person. This review found that the evidence was insufficient to draw reliable conclusions about the intervention, i.e., the use of these whitening products. The results indicated that people may experience side effects that irritate the mouth and gums. Therefore, nurses should direct people who are interested in teeth whitening to their dental professional for a discussion.

Separate contribution of dentin and enamel to color changes caused by staining pigments and dental bleaching

AIM

This study assessed the changes in color and translucency of dentin and enamel after staining and bleaching procedures as well as the contribution of the tissues to color change (CTCC).

MATERIALS AND METHODS

Fifty enamel-dentin specimens were obtained from bovine incisors and grouped into 10 blocks based on the similarity of the baseline color. One specimen in each block was used as the control, and the others were intrinsically (blood) or extrinsically (coffee) stained. One stained specimen for each pigment was bleached with 35% hydrogen peroxide. The enamel was separated from the dentin, and the tooth color and translucency parameter (TP) were measured individually and after recombining these substrates. Changes in color (ΔE00), whitening index (WI), and TP caused by the staining and bleaching procedures were estimated through assessing the color differences compared with the controls. CTCC was also calculated by recombining the enamel and dentin tissues from different treatments. The data were analyzed using the paired t test or the two-way repeated measures ANOVA (α = 0.05).

RESULTS

Extrinsic staining procedures produced higher color changes than intrinsic ones, except in dentin. The highest bleaching effect was observed in the dentin of specimens that were extrinsically stained. Similar CTCC values were observed for the dentin and enamel for both the staining and bleaching procedures. Except for the specimens that were treated with intrinsic staining and became more translucent after the bleaching procedure, the other treatments resulted in non-significant TP changes.

CONCLUSIONS

Staining the specimens extrinsically resulted in higher color change than staining them intrinsically, and these specimens were more affected by the bleaching procedure. Enamel and dentin demonstrated similar CTCC values.

Pulp response of rats submitted to bleaching and the use of different anti-inflammatory drugs

This study aimed to evaluate neuropeptide expression after bleaching treatment using histopathological and immunohistochemical analyses and the effects of hydrocortisone and acetaminophen on pulp inflammation, sine dental bleaching and inflammation first occur, and only then, the treatmentt. Sixty-three rats were divided into three groups (n = 21) according to the pain-relieving therapy used: I-control; II-topical application of Otosporin for 10 min after the bleaching treatment; III-oral administration of paracetamol 30 min before whitening and then every 12h. In all the study groups, placebo gel was applied to the left upper jaw (control) and a 35% H2O2-based whitening gel was applied to the right upper jaw for 45 min. Seven animals from each group were euthanized at different time points: 0h after treatment, 24h, and 48h. After euthanasia, the first molar on each side was analyzed by histology and immunohistochemistry to assess the degree of inflammation and verify the presence of the neuropeptides, substance P (SP) and calcitonin gene-related peptide (CGRP). The data were analyzed using the statistical nonparametric Kruskal-Wallis test followed by Dunn's test for individual comparisons. Extensive areas of necrosis were observed in the groups that received bleaching treatment only, whereas reduced damage were obtained in the group treated with Otosporin. The immunohistochemical analysis showed positive immunolabeling in all groups, including the control, but this was stronger in the groups that received bleaching treatment. The best results were obtained in the group that received treatment with Otosporin. The use of Otosporin after dental bleaching minimized the side effects of this treatment.

Does the antioxidant treatment affect the shear bond strength of orthodontic brackets: An in vitro study

OBJECTIVE

To determine the shear bond strength of orthodontic brackets after anti-oxidant treatment on previously bleached teeth..

METHODS

The experimental in-vitro study was conducted in Saudi Arabiaat Qassim University, Al-Qassim, and King Saud University, Riyadh, from December 2016 to March 2017, and comprised extracted maxillary and mandibular premolars which were divided randomly into three groups. In Group A, which was the control group, the teeth were etched and bonded, while those in Group B were bleached, etched and bonded. Group C was subjected to bleaching, followed by treatment with anti-oxidant 10% sodium ascorbate solution, then etched and bonded. All three groups were then tested and analysed for bond strength using the Instron, Universal testing machine. SPSS 23 was used for data analysis..

RESULTS

There were 60 teeth with 20(33.3%) in each of the three groups. Group C had the maximum mean shear bond strength of 12.231}2.1Mpa, followed by Group A with 10.948+/-2.1Mpa and Group B with 7.621}1.8Mpa.

CONCLUSIONS

Anti-oxidant treatment had a positive effect on the shear bond strength of orthodontic brackets after tooth bleaching. Keywords: Anti-oxidant. Bleaching, Brackets, Extracted premolars, Shear bond strength.

Home-based chemically-induced whitening (bleaching) of teeth in adults

BACKGROUND

With the increased demand for whiter teeth, home-based bleaching products, either dentist-prescribed or over-the-counter products have been exponentially increasing in the past few decades. This is an update of a Cochrane Review first published in 2006.

OBJECTIVES

To evaluate the effects of home-based tooth whitening products with chemical bleaching action, dispensed by a dentist or over-the-counter.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 12 June 2018), the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 6) in the Cochrane Library (searched 12 June 2018), MEDLINE Ovid (1946 to 12 June 2018), and Embase Ovid (1980 to 12 June 2018). The US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov (12 June 2018) and the World Health Organization International Clinical Trials Registry Platform (12 June 2018) were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included in our review randomised controlled trials (RCTs) which involved adults who were 18 years and above, and compared dentist-dispensed or over-the-counter tooth whitening (bleaching) products with placebo or other comparable products.Quasi-randomised trials, combination of in-office and home-based treatments, and home-based products having physical removal of stains were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials. Two pairs of review authors independently extracted data and assessed risk of bias. We estimated risk ratios (RRs) for dichotomous data, and mean differences (MDs) or standardised mean difference (SMD) for continuous data, with 95% confidence intervals (CIs). We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 71 trials in the review with 26 studies (1398 participants) comparing a bleaching agent to placebo and 51 studies (2382 participants) comparing a bleaching agent to another bleaching agent. Two studies were at low overall risk of bias; two at high overall risk of bias; and the remaining 67 at unclear overall risk of bias.The bleaching agents (carbamide peroxide (CP) gel in tray, hydrogen peroxide (HP) gel in tray, HP strips, CP paint-on gel, HP paint-on gel, sodium hexametaphosphate (SHMP) chewing gum, sodium tripolyphosphate (STPP) chewing gum, and HP mouthwash) at different concentrations with varying application times whitened teeth compared to placebo over a short time period (from 2 weeks to 6 months), however the certainty of the evidence is low to very low.In trials comparing one bleaching agent to another, concentrations, application method and application times, and duration of use varied widely. Most of the comparisons were reported in single trials with small sample sizes and event rates and certainty of the evidence was assessed as low to very low. Therefore the evidence currently available is insufficient to draw reliable conclusions regarding the superiority of home-based bleaching compositions or any particular method of application or concentration or application time or duration of use.Tooth sensitivity and oral irritation were the most common side effects which were more prevalent with higher concentrations of active agents though the effects were mild and transient. Tooth whitening did not have any effect on oral health-related quality of life.

AUTHORS' CONCLUSIONS

We found low to very low-certainty evidence over short time periods to support the effectiveness of home-based chemically-induced bleaching methods compared to placebo for all the outcomes tested.We were unable to draw any conclusions regarding the superiority of home-based bleaching compositions or any particular method of application or concentration or application time or duration of use, as the overall evidence generated was of very low certainty. Well-planned RCTs need to be conducted by standardising methods of application, concentrations, application times, and duration of treatment.

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.

Effect of Toothpaste Use Against Mineral Loss Promoted by Dental Bleaching

AIM

To investigate the effect of different toothpaste formulations used prior to dental bleaching with 35% hydrogen peroxide (HP) on the mineral content and surface morphology of enamel.

METHODS

Seventy bovine enamel blocks (4×4×2 mm) were submitted to in vitro treatment protocols using a toothbrushing machine prior to dental bleaching or a placebo procedure (n=10) as proposed in the following groups: unbleached control (PLA), bleached control (HP), and brushing with differing toothpastes prior to HP bleaching, including: potassium nitrate toothpaste containing sodium fluoride (PN), sodium monofluorophosphate/MFP toothpaste (FT), arginine-carbonate (8% arginine) (PA) or arginine-carbonate (1.5% arginine) toothpaste (SAN), and toothpaste containing bioactive glass (NM). Phosphorus concentration in gel ([P]) was evaluated (μg of P/mg of gel), and the elemental levels (wt%) of Ca, P, and Na as well as the proportion between Ca and P and spectra graphics were determined using an energy-dispersive X-ray spectrometer (EDS). The surface morphology was assessed using scanning electron microscopy (SEM). The data were subjected to analysis of variance and the Tukey test (α=0.05).

RESULTS

HP demonstrated the greatest [P] values in gel, being statistically different from PLA. The [P] of NM was statistically similar to PLA. HP showed a significant decrease in the Ca% and Ca/P values when compared to PLA in EDS analysis. PA showed Ca/P values statistically different from HP. In accordance with SEM analysis, the PA, SAN, and NM groups presented a smooth and uniform enamel surface, while HP and FT demonstrated some alterations in morphology.

CONCLUSION

The toothpastes containing bioactive glass or arginine carbonate used prior to dental bleaching were effective in protecting enamel against mineral loss promoted by the whitening procedure.

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.

Effect of Different Intraorifice Barriers and Bleaching Agents on the Fracture Resistance of Endodontically Treated Anterior Teeth

INTRODUCTION

Intraorifice barriers (IOBs) are usually used before internal bleaching for coronal sealing and the prevention of cervical resorption. The aim of this study was to investigate the effect of different IOBs on the fracture resistance (FR) of endodontically treated anterior teeth bleached with various bleaching agents (BAs).

METHODS

After performing root canal treatment for 72 extracted bovine upper incisors, the coronal 3 mm of gutta-percha was removed, and samples were classified into 3 based on the type of IOB: calcium-enriched mixture, mineral trioxide aggregate, and resin-modified glass ionomer. After applying IOBs, samples of each group were subdivided into 4 based on the BA: carbamide peroxide 45% (CP), hydrogen peroxide 35% (HP), sodium perborate (PB), and distilled water as the control. At the end of bleaching, the access cavities were restored with composite resin. The FR was measured with a universal testing machine at a crosshead speed of 5 mm/min. The data were analyzed using 2-way analysis of variance and least significant difference post hoc tests (P < .05).

RESULTS

The effect of BAs on the FR was significant (P < .05); however, the effect of the IOB and the interactive effect of these variables were not significant (P > .05). The FR in the HP and PB groups was significantly different from the control (P < .05) but that of CP was not significantly different from the control (P > .05).

CONCLUSIONS

Mineral trioxide aggregate and calcium-enriched mixture act similarly to resin-modified glass ionomer as an IOB. CP, unlike HP and PB, did not significantly decrease the FR.

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.

Efficacy of ibuprofen and codeine + paracetamol to reduce immediate bleaching sensitivity caused by in-office tooth bleaching: A randomized, controlled, double-blind clinical trial

PURPOSE

To evaluate (1) the efficacy of Ibuprofen and codeine + paracetamol to control immediate bleaching sensitivity caused by in-office tooth bleaching performed with 35% hydrogen peroxide, and (2) tooth shade change caused by 35% hydrogen peroxide.

METHODS

In this randomized, controlled and double blind clinical trial, 60 volunteers were divided into three treatment groups: 400 mg placebo (PL)(n=20), 400 mg ibuprofen (IB)(n=20), or 30 mg codeine + 500 mg paracetamol (CP)(n=20). The volunteers were submitted to two bleaching sessions with 35% hydrogen peroxide in 2 applications of 20 minutes each. In both sessions, the medication was given to the volunteers 1 hour before the bleaching procedure. The sensitivity values were obtained with the analogic visual pain scale. Tooth shade was assessed before and after bleaching. Statistical analysis was done through the one-way ANOVA and Tukey post-hoc tests.

RESULTS

For bleaching sensitivity, there were statistically significant differences among the medications (P< 0.01). The lowest sensitivity means were found in the CP group (PL:4.7 = IB:4.8 > CP:1.0). In regards to tooth shade, participant's teeth were statistically significantly lighter after bleaching than before bleaching (P< 0.01), with no statistically significant difference between the medications (P< 0.05).

CLINICAL SIGNIFICANCE

The use of codeine + paracetamol 1 hour before in-office tooth bleaching can drastically reduce immediate sensitivity.

Preventive Use of a Resin-based Desensitizer Containing Glutaraldehyde on Tooth Sensitivity Caused by In-office Bleaching: A Randomized, Single-blind Clinical Trial

OBJECTIVE

To evaluate the risk and intensity of bleaching-induced tooth sensitivity (TS) after in-office bleaching following topical application of a resin-based glutaraldehyde desensitizer.

METHODS

Thirty-three patients were randomly assigned to the experimental (Gluma Desensitizer Liquid, Heraeus Kulzer, Hanau, Germany) and placebo groups. The placebo or Gluma Desensitizer Liquid was applied for one minute prior to application of an in-office bleaching gel. Bleaching was performed with 35% hydrogen peroxide gel (three applications × 15 minutes each) over two sessions, one week apart. The color of the anterior teeth was evaluated before and 21 days after treatment using the VITA Classical shade guide, Bleachedguide 3D, and Easyshade spectrophotometer. TS during and after the bleaching was recorded according to the visual analog (VAS) and numerical rating (NRS) scales. All data were submitted to statistical analysis (α=0.05).

RESULTS

There was no significant difference in absolute risk or intensity of TS between the two groups (risk and VAS, p=0.93 and 0.31, respectively; NRS, p≥0.45). At the end of the bleaching protocol, tooth whitening was observed in both groups, as evident from color change in shade guide units (ΔSGU, 4.1-7.1; both guides) and overall color change (ΔE, 7.4-9.3 units); however, there were no significant differences in whitening between the two groups ( p>0.11).

CONCLUSION

Gluma Desensitizer Liquid was not able to reduce the risk or intensity of TS. Bleaching efficacy was not affected by application of the desensitizer.