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

Effectiveness of violet LED with or without a bleaching gel: a 12-month randomized clinical trial

Introduction

The present interventional, controlled, randomized, blind clinical study aimed to evaluate the effectiveness of an in-office bleaching procedure with violet LED associated or not with 37% carbamide peroxide, considering as response variables the degree of change and color stability over 12 months and dental sensitivity over a month.

Methods

Forty participants, according to the inclusion and exclusion criteria, were randomly divided into 2 groups (n = 20) according to the bleaching protocol conducted, in two sessions, with a 7-day interval: vLED-violet LED, without gel; vLED/CP-37% carbamide peroxide photocatalyzed with violet LED (control group). In the vLED group, in each session the bleaching was carried out by 2 consecutive irradiation cycles of 25' each (10 × 2' LED + 30" interval), with 5' interval between cycles. In the vLED/CP group, the gel was applied 5 times in the bleaching session and photocatalyzed 3 times for 2' with 30" intervals (7'30" per gel application), totaling 37'30" per session. Dental sensitivity was assessed using a visual analog scale (VAS) and the effectiveness of bleaching as a function of the degree of change and color stability (ΔE) with a spectrophotometer. The data were tabulated and submitted to statistical tests (p < 0.05).

Results

The VAS analysis showed that some individuals from both groups had mild pain (1 ≤ VAS < 4) during the time intervals evaluated, being more prevalent in the vLED/CP group. Regarding the degree of color change, the groups behaved differently over time (p < 0.0001). The ΔE observed for the vLED/CP group was superior in comparison to the vLED group at all evaluated moments.

Conclusions

Over 12 months, the vLED/CP group was more effective in relation to the bleaching effect compared to the vLED group. Both groups showed low levels of sensitivity in the studied time intervals.

Clinical Trial Registration

[https://ensaiosclinicos.gov.br/rg/RBR-6rc23h], identifier [U1111-1253-8850].

Effect of Low- and High-Level Laser Therapy on the Treatment of Dentin Hypersensitivity: An Umbrella Review

Introduction: Dentin hypersensitivity (DH) is a prevalent unpleasant condition which might affect quality of life. Laser therapy is one of the non-invasive treatments for dentin hypersensitivity. The aim of this umbrella review was to assess the effect of lasers on the treatment of dentin hypersensitivity by analyzing the previously published systematic reviews and meta-analyses. Methods: Electronic databases (PubMed, Embase, Scopus, Cochrane, and ISI) were searched to identify relevant systematic reviews and meta-analyses based on the keyword search strategy. Two independent reviewers carried out the selection of studies, extraction of data, and assessment of methodological quality. The actual overlap of primary studies was measured through the visual tool known as the citation matrix and three indices of % overlaps, covered area (CA), and corrected covered area (CCA). The reviews were appraised for methodological quality through A Measurement Tool to Assess Systematic Reviews (AMSTAR)-2, and the risk of bias was evaluated using the Risk of Bias in Systematic Reviews (ROBIS) tool. Results: Following eliminating duplicates, a total of 2,768 articles were found, and of them, 9 systematic reviews met the inclusion criteria. Six of them included a meta-analysis as well. The actual overlap of primary studies was low. The AMSTAR 2 tool classified one systematic review as high quality, three as moderate quality, three as low quality, and the remaining two as critically low quality. The results of the included reviews generally showed that all types of lasers reduced dentin hypersensitivity compared to placebo/no treatment. Conclusion: Lasers are effective in treating dentin hypersensitivity.

In-office Bleaching Activated With Violet LED: Effect on Pulpal and Tooth Temperature and Pulp Viability

OBJECTIVES

This study evaluated the influence of hydrogen peroxide (HP) with or without titanium dioxide nanotubes (TiO2) associated with violet LED (VL) regarding: a) the temperature change in the pulp chamber and facial surface; b) the decomposition of HP; and c) the cytotoxicity of the gels on pulp cells.

METHODS AND MATERIALS

The experimental groups were: HP35 (35% HP/Whiteness HP, FGM); HP35+VL; HP35T (HP35+TiO2); HP35T+VL; HP7 (7.5% HP/White Class 7.5%, FGM); HP7+VL; HP7T (HP7+TiO2); and HP7T+VL. TiO2 was incorporated into the bleaching gels at 1%. Eighty bovine incisors were evaluated to determine temperature change in 8 experimental groups (n=10/group). A k-type thermocouple was used to evaluate the temperatures of the facial surface and in the pulp chamber, achieved by enabling endodontic access to the palatal surface, throughout the 30-minute session. HP decomposition (n=3) of gels was evaluated by using an automatic potentiometric titrator at the initial and 30-minute time points. Trans-enamel and trans-dentinal cell viability were assessed with a pulp chamber device as well as enamel and dentin discs (n=6), and the treatment extracts (culture medium + diffused components) were collected and applied to MDPC-23 odontoblast cells to evaluate cell viability according to the MTT test.

RESULTS

A temperature increase in the pulp chamber was observed in the presence of VL at 30 minutes (p<0.05) (Mann-Whitney test). Also at 30 minutes, HP35 showed greater decomposition in the presence of VL rather than in its absence (p<0.05) (mixed linear models and the Tukey-Kramer test). HP7 provided greater cell viability than the groups treated with HP35 (p<0.05) (generalized linear models test). Cell viability was significantly lower for HP7 in the presence of VL (p<0.05).

CONCLUSION

Pulpal temperature increased with VL (maximum of 1.9°C), but did not exceed the critical limit to cause pulp damage. Less concentrated HP resulted in higher cell viability, even when associated with VL.

Effect of antioxidant on tooth sensitivity after bleaching

OBJECTIVES

This study aimed to investigate the effect of antioxidant (sodium ascorbate) on tooth sensitivity after two in-office bleaching techniques (light-activated and chemical bleaching).

MATERIALS AND METHODS

Ten patients aged 18-25 were bleached in four groups according to bleaching materials and/or antioxidant used. Group A: Maxillary right quadrant received light-activated bleaching with antioxidant. Group B: Maxillary left quadrant received light-activated bleaching without antioxidant. Group C: Mandibular right quadrant received chemical bleaching without antioxidant. Group D: Mandibular left quadrant received chemical bleaching with antioxidant. The tooth sensitivity was recorded using Numerical Rating Scale (NRS) and Schiff Scale (SS) immediately after treatment, 1 day, 1 week, 2 weeks, and 1 month follow-up periods.

RESULTS

Group B exhibited higher sensitivity values than Group A. This difference was statistically significant on the first day after treatment (p = 0.027* in NRS and p = 0.046* in SS). Furthermore, antioxidant incorporation in Group D led to a reduction in teeth sensitivity values compared to Group C. This disparity was highly significant on the first day after treatment (p = 0.001* in NRS and p < 0.001** in SS).

CONCLUSIONS

The antioxidant (10% sodium ascorbate) reduces the intensity of tooth sensitivity at the different follow-up periods, especially after 1 day from bleaching.

CLINICAL SIGNIFICANCE

Using 10% sodium ascorbate after bleaching is advisable to reduce post-operative tooth sensitivity.

Hybrid light applied with 37% carbamide peroxide bleaching agent with or without titanium dioxide potentializes color change effectiveness

BACKGROUND

The effectiveness of dental color change was assessed by incorporating titanium dioxide (TiO2) into 37% carbamide peroxide bleaching agent associated with hybrid light.

METHODOLOGY

Fifty bovine incisors were selected to receive the bleaching treatment, and separated into five groups (n = 10): 35% hydrogen peroxide (HP) (Whiteness HP, FGM/HP); 37% carbamide peroxide (CP) (Whiteness SuperEndo, FGM/CP); CP + hybrid light (HL) (CP HL); CP + 1% TiO2 (CP TiO2); CP TiO2 + hybrid light (CP TiO2 HL). The bleaching gels were applied to the dental surface for 30 min. Hybrid light (Whitening Plus, DMC/infrared laser diodes + blue LEDs +violet LEDs) was applied with 1 min of active light, alternating with 1 min of pause. A spectrophotometer (VITA Easyshade® Advance, Vita) was used to determine the color of the dental elements at baseline and time points after the 1st, 2nd and 3rd bleaching sessions. Color change effectiveness was evaluated using Vita Classical, CIEL*a*b*, WID and ΔEab, ΔE00 and ΔWID parameters.

RESULTS

Generalized mixed linear models for repeated measures (α = 5%) showed significant decrease in Vita Classical scores and a* and b* values, as well as an increase in L* and ∆WID values for all the groups. Higher color change values for ΔEab were observed for CP HL and CP TiO2 HL, while those of ΔE00 and ΔWID were higher for CP TiO2 HL at the end of the bleaching treatment.

CONCLUSION

Hybrid light applied with TiO2 incorporated into CP potentiated the effectiveness of the color change in the tooth structure.

The Use of Diode Low-Power Laser Therapy before In-Office Bleaching to Prevent Bleaching-Induced Tooth Sensitivity: A Clinical Double-Blind Randomized Study

INTRODUCTION

The present study aimed to investigate the effectiveness of low-level laser therapy (LLLT) use before in-office bleaching to prevent an increase in the risk and intensity of tooth sensitivity.

METHODS

Thirty patients were selected. Before bleaching with 38% hydrogen peroxide, the participants were randomly divided into two groups of 15 subjects. Test group: the patients' teeth were subjected to a preliminary LLLT procedure by an 810 nm diode laser with 0.5 W for 30 s for an energy density of 15 J/cm² and a group placebo. All patients were instructed to report their cold sensitivity experiences immediately, 1 h, 24 h, and 48 h after the end of bleaching via a VAS score.

RESULTS

The results obtained show an increase in VAS values for both groups (290 and 490 vs. 224 and 234 of baseline time of test and placebo group, respectively); afterward, the VAS value seemingly decreases at 1 h after the end of bleaching, approaching the baseline VAS for the test group (274) in comparison to the placebo group.

CONCLUSIONS

The use of preliminary diode LLLT could represent a valid possibility to reduce the occurrence of tooth sensitivity post-whitening and shorten recovery time in cases where tooth sensitivity occurs.

Evaluation of the laser wavelength role on tooth bleaching in terms of color change, roughness, and microhardness with pulpal rapid temperature monitoring: an in vitro study

This in-vitro study evaluates the efficacy of the teeth bleaching approach using different laser wavelengths (405 nm blue diode, 940 nm infrared diode, and Er,Cr:YSGG 2780 nm lasers) in comparison to the conventional method using light-emitting diode (LED) sources (420-480) nm. Eighty caries-free sound human premolars were randomly divided into four groups (N=20). Each group received a different bleaching procedure. Then each group was further subdivided into two subgroups (N=10) stained with different solutions. The pulp chamber temperature rise was recorded using an optical fiber sensor with a novel design and fabrication. The color was analyzed using a digital spectrophotometer. Five samples of each subgroup were tested for surface roughness, while the others were tested for Vickers microhardness. The bleaching process with a short wavelength 405 nm blue diode laser showed the best results for the shade, with a minimum pulpal temperature increase indicating no possible necrosis and hence maintaining tooth vitality. Additionally, a remarkable reduction in bleaching time was achieved compared to the conventional approach. This process also yielded the highest color change (Δ E) and increased microhardness, with no noticeable change to the tooth roughness. The 405 nm blue diode laser applied for bleaching showed the best bleaching activity against tested stains and negligible pulpal temperature rise with a noticeable reduction in the bleaching time. The proposed novel method to measure temperature change could be used to develop a promising smart sensor for quick, effective, repeatable, and in-situ monitoring of human body temperature.

Effect of non-vital tooth bleaching photoactivated with blue or violet LED on color and microhardness

BACKGROUND

To evaluate the efficacy of non-vital dental bleaching protocols using 35% hydrogen peroxide photoactivated with violet LED on color and microhardness of endodontically treated teeth.

METHODS

Forty specimens were selected and randomized into 4 groups (n = 10): C - Control, HP - 35% hydrogen peroxide, HP + BL - 35% hydrogen peroxide + blue LED, HP + VL - 35% hydrogen peroxide + violet LED. Three bleaching sessions were performed for each group. Color analysis was performed 7 days after each bleaching session. Two-way repeated measure ANOVA and Bonferroni test were used to evaluate the effect of different bleaching protocols and evaluation times on the dependent variables (∆E and ∆L). Dentin microhardness was measured 24 hours after the third bleaching session. Data were evaluated by ANOVA and Tukey's test at a significance level of 5%.

RESULTS

Differences on ∆E and ∆L were verified after the first and second bleaching sessions (p < 0.05) and showed stability after the third one, for all the groups. No differences were observed among HP, HP + BL, and HP + VL groups, regardless of the evaluation time (p > 0.05). HP and C showed the greatest and smallest reduction in dentin microhardness (p < 0.05), respectively. No difference between HP + BL and HP + VL protocols (P > 0.05) was observed.

CONCLUSIONS

High concentration hydrogen peroxide (35%) photoactivated with violet LED bleached endodontically treated teeth effectively. However, the same protocol negatively affected the dentin microhardness, but not in the same level of 35% HP solely used.

Post-Operative Sensitivity and Color Change Due to In-Office Bleaching With the Prior Use of Different Desensitizing Agents: A Systematic Review

Bleaching agents can cause certain surface alterations on the enamel, such as depressions, surface porosity, and surface irregularities; this makes the dentin more susceptible to post-operative tooth sensitivity (PoS). In addition, the presence of flawed or leaky restorations, gingival recession, or defects in the cementoenamel junction can also cause severe tooth sensitivity post tooth bleaching.Hence, the current study aimed to perform a systematic review to determine the efficacy of various desensitizing agents (DA) in managing post-operative tooth sensitivity and color alteration when applied before in-office bleaching procedures. Randomized clinical trials were searched to conduct an SR where the post-operative tooth sensitivity was evaluated after in-office bleaching with various desensitizing agents used before the procedure. Post-operative pain assessment was measured using the Visual Analogue Scale (VAS). Outcomes were evaluated up to an hour and 24 hours post the procedure. Out of 163 articles, only 13 titles were selected that met the eligibility criteria. Eight hundred and forty-one adult patients with vital pulp status were included. The participants receiving prior desensitizing agent applications reported significantly lower pain scores in the VAS reports. The most significant reduction of post-operative sensitivity was observed in the immediate (up to an hour) and 24 hours after the in-office bleaching. The popular desensitizing agent that could manage post-operative tooth sensitivity (TS) is 5% potassium nitrate and 2% sodium fluoride used before the in-office bleaching procedure. 

Evaluation of bleaching efficacy, microhardness, and trans-amelodentinal diffusion of a novel bleaching agent for an in-office technique containing hexametaphosphate and fluoride

OBJECTIVE

This study evaluated in vitro the effects of calcium gluconate (CaGlu), sodium fluoride (NaF), sodium hexametaphosphate (HMP), and NaF/TMP added to a 35% hydrogen peroxide (H₂O₂) bleaching gel on the color change, enamel hardness, and trans-amelodentinal diffusion.

MATERIALS AND METHODS

Enamel discs/bovine dentin (n = 150) were divided according to the bleaching gel: 35% H₂O₂ (H₂O₂); 35% H₂O₂ + 0.1% NaF (H₂O₂/NaF); 35% H₂O₂ + 1% HMP (H₂O₂/HMP); 35% H₂O₂ + 0.1% NaF + 1% HMP (H₂O₂/NaF/HMP), and 35% H₂O₂ + 2% CaGlu (H₂O₂/Caglu). The bleaching gels were applied three times (40 min/session) at 7-day intervals between each application. Then, color alteration (ΔE), whitening index (ΔWI_D), percentage of surface hardness loss (% SH), cross-sectional hardness (ΔKHN), and trans-amelodentinal diffusion were determined. Data were submitted for analysis of variance (ANOVA), followed by the Student-Newman-Keuls test (p < 0.05).

RESULTS

All bleaching gels showed significant color changes after treatment (p < 0.001). ΔE and ΔWI_D were similar among the evaluated gels. Mineral loss (% SH and ΔKHN) and trans-amelodentinal diffusion of hydrogen peroxide were lower for H₂O₂/NaF/HMP; the H₂O₂/CaGlu group presented the highest values about the other groups (p < 0.001).

CONCLUSION

It is possible to conclude that the addition of NaF/HMP to the in-office bleaching agent did not interfere with the bleaching efficacy and reduced enamel demineralization and H₂O₂ diffusion.

CLINICAL SIGNIFICANCE

The association of NaF/HMP to the bleaching gel can be used as a novel approach for minimizing the adverse effects of H₂O₂ by-products and with similar clinical efficacy.

EVALUATION OF MINERAL CONTENT OF TOOTH ENAMEL AFTER APPLICATION VIOLET LED ASSOCIATED WITH 35% HYDROGEN PEROXIDE

BACKGROUND

The aim of this study was to evaluate the microhardness and quantify the presence of minerals (Calcium and Phosphorous) of tooth enamel submitted to bleaching with violet LED light, either associated with 35% hydrogen peroxide gel, or not.

METHODS

Bovine incisors were selected and divided into 4 Groups according to the bleaching technique used: C- Without bleaching (Control); VL- violet LED; HP- 35% Hydrogen Peroxide; HP+VL- 35% Hydrogen Peroxide + violet LED. The response variables were surface microhardness (n=12), Energy Dispersive Spectroscopy (EDS) (n=6) and scanning electron microscopy (SEM) (n=3).

RESULTS

The 2-way ANOVA test with repeated measures showed that there was difference in the microhardness values of enamel in the specimens in all of the Groups when the values measured in the initial and final time intervals were compared, however, without significant differences between the values of the different treatments in both time intervals. The results with reference to EDS were analyzed with the 1-way ANOVA test. There was difference among the Groups only in the Ca%, with Group HP obtaining the lowest values, with significant difference from those of the C Group. SEM images showed a smooth, homogeneous enamel surface and similarity among the Groups, irrespective of the treatment performed.

CONCLUSIONS

Therefore, it was concluded that the changes caused in enamel by the use of violet LED Light, either associated with 35% hydrogen peroxide, or not, did not differ from those of non-bleached tooth enamel, showing absence of harm to the mineral content of tooth enamel resulting from the use of violet LED.

Expanding the applications of photodynamic therapy-tooth bleaching

OBJECTIVES

The current tooth bleaching materials are associated with adverse effect. Photodynamic method based on a novel photosensitizer alone, without combining with peroxides, is evaluated for tooth bleaching application.

MATERIALS AND METHODS

Teeth samples were randomly divided into 3 groups with different treatment schemes, including negative control group (group A, physiological saline), experimental group (group B, ZnPc(Lys)5), and the positive control group (group C, hydrogen peroxide). Tooth color, surface microhardness, and roughness were determined at baseline, right after the first and second phase of bleaching, as well as 1 week and 1 month post-bleaching. Four samples in each group was randomly selected to evaluate the changes in surface morphology using the scanning electron microscope.

RESULTS

The color change values (ΔE) in group B (7.10 ± 1.03) and C (12.22 ± 2.35) were significantly higher than that in group A (0.93 ± 0.30, P < 0.05). Additionally, surface microhardness and roughness were significantly affected in group C, but not in the group A and B. Furthermore, the scanning electron microscope images showed no adverse effect of enamel in the group A and B while the group C demonstrated corrosive changes.

CONCLUSIONS

ZnPc(Lys)5 had a satisfactory bleaching effect and is promising to be a new type of tooth bleaching agent.

CLINICAL RELEVANCE

The current tooth bleaching materials give a satisfactory clinical outcome and long-term stability, but associated with some adverse reactions. Photosenstizer ZnPc(Lys)5 eliminated the main side effects observed in hydrogen peroxide-based agents on the enamel, and also had a satisfactory bleaching effect and provide a novel selective bleaching scheme for clinical use.

In-office dental bleaching with violet-LED: bleaching efficacy and pulpal temperature rise

Objectives

This study evaluated the bleaching efficacy of different in-office protocols associated with violet light emitting diode (V-LED), and measured the pulpal temperature rise caused by V-LED with or without gel application.

Materials and Methods

Bovine incisors were distributed in 4 groups (n = 10): VL – V-LED; HP – 35% hydrogen peroxide (control); HYB – hybrid protocol, V-LED applied without gel for 10 irradiation cycles followed by V-LED applied with gel for another 10 irradiation cycles; and HPVL – gel and V-LED applied for 20 irradiation cycles. Three bleaching sessions were performed with 7-day intervals. Bleaching efficacy was evaluated with ΔEab*, ΔE₀₀ and ΔWI_D. Data were recorded at baseline, 7, 14, 21 and 70 days. For pulpal temperature rise, thermocouples were placed inside the pulp chamber of human incisors. To determine intrapulpal temperature, the teeth were irradiated with V-LED with or without application of bleaching gel. Color difference data were analyzed by 2-way repeated measures ANOVA and Tukey’s test. Pulpal temperature was analyzed by t-test (α = 5%).

Results

VL exhibited lower color (ΔEab* and ΔE₀₀) and whiteness changes (ΔWI_D) than the other groups. HPVL presented higher color change values than HYB. HYB and HPVL showed not different ΔWI_D values; and HP showed the highest whiteness changes at all times. There were significant differences comparing ΔT with gel (8.9°C) and without gel application (7.2°C).

Conclusions

HPLV was more efficient than HYB. The 2 protocols with VL showed similar results to control. Gel application combined with VL promoted higher pulpal temperature than to the no gel group.

Evaluation of dental enamel microproperties after bleaching with 35% hydrogen peroxide and different light sources: An in vitro study

Background

To evaluate the tooth enamel surface morphology after the action of 35% hydrogen peroxide with and without LED activation.

Material and Methods

70 bovine incisors with an enamel surface of 4x4x3 mm were used, prepared for reading superficial microhardness and roughness. Specimens were randomly distributed and divided into 7 experimental groups (n = 10); G1 = artificial saliva; G2 = 35% HP - 2 sessions (3x15´); G3 = Phosphoric Acid + 35% HP - 3 sessions (3x15´); G4 = 35% HP - 2 sessions (3x15´) + blue LED; G5 = 35% HP - 2 sessions (3x15´) + green LED; G6 = 35% HP - 2 sessions (3x20´) + violet LED; G7 = Violet LED - 2 sessions (3x20´). The results were analyzed by the Anova, Wilcoxon, Dunnett and Tukey tests (α = 0.05).

Results

The G4 group showed a greater change in microhardness. Regarding roughness, the biggest mean difference between groups occurred in G2, G5 and G7. Optical microscopy showed a smooth enamel surface in groups G2, G5 and G7.

Conclusions

Changes in the enamel surface were observed in relation to microhardness, but without significant changes in roughness, where the LED (green and violet) resulted in a smooth surface. Key words:Tooth whitening, superficial morphology, light, photoradiatio.

Evaluation of Tooth Sensitivity of In-office Bleaching with Different Light Activation Sources: A Systematic Review and a Network Meta-analysis

OBJECTIVES

A systematic review and network meta-analysis were performed to answer the following research question: Are there differences in the risk and the intensity of tooth sensitivity (TS) among eight light activation systems for in-office bleaching in adults?

METHODS

Randomized controlled trials (RCTs) that compared at least two different in-office bleaching light activations were included. The risk of bias (RoB) was evaluated with the RoB tool version 1.0 from the Cochrane Collaboration tool. A random-effects Bayesian mixed treatment comparison (MTC) model was used independently for high- and low-concentration hydrogen peroxide. The certainty of the evidence was evaluated using the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) approach. A comprehensive search was performed in PubMed, Bridge Base Online (BBO), Latin American and Caribbean Health Sciences Literature database (LILACS), Cochrane Library, Scopus, Web of Science, and grey literature without date and language restrictions on April 23, 2017 (updated on September 26, 2019). Dissertations and theses, unpublished and ongoing trials registries, and IADR (International Association for Dental Research) abstracts (2001-2019) were also searched.

RESULTS

After title and abstract screening and the removal of duplicates, 32 studies remained. Six were considered to be at low RoB, three had high RoB, and the remaining had an unclear RoB. The MTC analysis showed no significant differences among the treatments in each network. In general, the certainty of the evidence was graded as low due to unclear RoB and imprecision.

CONCLUSION

There is no evidence that the risk and intensity of TS are affected by light activation during in-office bleaching.

In Vitro Evaluation of the Effectiveness of Dental Bleaching with Carbamide Peroxide and Violet Light

Objective: The aim of the current study was to use the CIELab system to evaluate the performance of the whitening treatment involving violet light-emitting diode (LED) combined with a home 10% and 22% carbamide peroxide dental bleaching technique on dental enamel. Methods: Fifty blocks of bovine dental enamel were divided into five groups: control group (control), receiving only LED irradiation; Whitening 10%, receiving 10% carbamide peroxide treatment; Whitening 10%+VL, receiving 10% carbamide peroxide treatment combined with LED irradiation; Whitening 22%, receiving 22% carbamide peroxide treatment; and Whitening 22%+VL, receiving 22% carbamide peroxide treatment combined with violet LED irradiation. Color tests were performed before the protocols, after 1 week and after 2 weeks of treatment by using a spectrophotometer and the CIELab parameters: L*, (a*) and (b*). The Whitening 10%, Whitening 10%+VL, Whitening 22% and Whitening 22%+VL groups were submitted to 10% and 22% carbamide peroxide 8 h per day for 14 days, whereas the Control was only stored in artificial saliva. For irradiation in the Control, Whitening 10%+VL, and Whitening 22%+VL groups, we used violet LED at a wavelength of 405-410 nm activated for 60 permanent seconds and 30 sec of pause once per week. As all data exhibited normal distribution, the comparisons were performed by using two-way repeated-measures analysis of variance. A post hoc t-test was employed, followed by the Ryan-Holm stepdown Bonferroni procedure. Results: After 1 week, the Whitening 22%+VL group differed significantly from all other groups in relation to hue, while no difference was found between the remaining groups (p < 0.05). Analyzing lightness, the Whitening 22%+VL and Whiteness10%+VL groups differed from the other groups (p > 0.05). In the 2nd week, the Whitening 22%+VL groups differed significantly from all other groups (p < 0.05) in hue, chroma, and lightness. The comparative analysis of bleaching times within the same group revealed significant differences in the Whitening 22%+VL group between baseline and week 1, baseline and week 2, as well as weeks 1 and 2 in terms of hue (p > 0.05). In the Whitening 22%+VL group, significant differences (p < 0.05) were found between baseline and week 2 as well as between weeks 1 and 2 in chroma (p > 0.05). In the Whitening 22%+VL group, statistically significant differences (p < 0.05) were found between baseline and week 1, baseline and week 2, as well as between weeks 1 and 2 in lightness. In the Whitening 10%+VL group, statistically significant differences (p < 0.05) were found between baseline and week 1, between baseline and week 2, as well as between weeks 1 and 2 in lightness. Conclusions: Tooth whitening treatment involving 10% and 22% carbamide peroxide combined with violet light promoted changes in the three axes of color (ΔH, ΔC, and ΔL) of the specimens evaluated. The use of the gel bleach alone was more efficient when the higher concentration was used. When violet light was combined with the gel, the lower concentration was more efficient.

Clinical evaluation of in-office tooth whitening with violet LED (405 nm): A double-blind randomized controlled clinical trial

BACKGROUND

Although there is little evidence showing the effectiveness of violet LED on in-office tooth whitening, there are some studies which have reported satisfactory results. This double-blind randomized controlled clinical trial aimed to evaluate the effect of a violet light emission diode (LED) (405 nm) system, used in-office, on tooth whitening, sensitivity, use of medication after whitening and quality of life.

METHODS

Eight patients were randomized into 4 groups (n = 20): G1 - violet LED, G2 - 35% carbamide peroxide (CP) and violet LED, G3 only CP 35% and G4 35% hydrogen peroxide (HP). The color was measured using a spectrophotometer at the following times: baseline, 15 and 180days. The colorimetric changes were analyzed using measurements from the CieLab System ΔE (ΔL, Δa and Δb) and the WID (Whiteness Index for Dentistry) for the 4 groups. Tooth sensitivity was recorded via a visual analog scale (VAS). Additionally, the Psychosocial Impact of Dental. Aesthetics Questionnaire (PIDAQ) was used to evaluate quality of life.

RESULTS

For the analysis of ΔL, G4 and G2 presented more brightness than G1 and G3 (p<0.05), implying that G2 is at least as good as G4 (p>0.05). For measure of Δa, G4 presented better results, standing out from the other groups. (p<0.05). For Δb, both G4 and G2 showed a greater tendency for blue color than groups G1 and G3 (p <0.05). When analyzing ∆E at the 180-day follow up, G4 produced the highest ∆E, while G3 showed the lowest ∆E. The other 2 whitening groups produced intermediate ∆E values. For ∆W, G1 and G3 significantly differed from G2 and G3. When analyzing the 180-day follow up, G2 produced the highest ∆W, while G3 showed the lowest ∆W. The other two whitening treatments produced intermediate ∆W values. As for sensitivity, only G4 patients showed dental sensitivity within 24 h of the bleaching, with pain ceasing after 48 h. For G4, 33% of the patients needed to take analgesics within the first 24 h after the first 3 whitening sessions. For PIDAQ, there was no overall decrease in score over time for any of the groups and there was no difference between them (p>0.05).

CONCLUSION

Our results showed that violet LED was not able to whiten teeth at the same intensity, when used alone, as it was when associated with 35% CP, contrary to our initial hypothesis. However, given that pain was not consistently reported in G2, one could suggest that treatment with LED + 35% CP is quite similar to that of 35% HP when used for tooth whitening, but with better pain outcomes. All treatments suggested an improvement in quality of life.Clinical Trial Registry: This trial is registered at ClinicalTrials.gov; the registration number is NCT03192852 https://clinicaltrials.gov/ct2/show/NCT03192852.

Effect of photo-thermal acceleration on in-office bleaching

The purpose is to evaluate the effect of photo-thermal acceleration on in-office bleaching efficiency using a bleaching agent without photocatalysts in vitro. Artificially discolored bovine lower incisors were prepared, and the mixed in-office bleaching material contained hydrogen peroxide 23% was applied by following treatment for 10 min: high-(HI group) and low-intensity LED lights (LI group), oven at 38 °C (OV group), and room temperature at 23 °C (RT group). Color was measured before and after bleaching and color difference (∆E*) was calculated. The data were statistically analyzed using a two-way ANOVA and Tukey’s post hoc test. The temperature change (∆T) of applied bleaching agent in HI and LI groups was measured using a thermography and was analyzed using a T test. The bleaching procedures were repeated 6 times. Irradiation in the HI group resulted in the highest ΔE, followed by the LI group whose ΔE was significantly lower. Both irradiated modes exhibited higher ΔE compared to non-irradiated OV and RT groups which were not significantly different from each other. The average temperature rise of bleaching agents in HI and LI groups after 10 min irradiation was 15.00 °C and 11.80 °C, respectively. The effect of photo-thermal acceleration was proved for an in-office bleaching agent without photocatalysts in vitro.

Insights into blue light accelerated tooth whitening

Objective

To test the hypotheses that blue light accelerates whitening through either (1) direct photobleaching or (2) photon-assisted oxidation using sequential longitudinal bleaching.

Methods

Thirty extracted human tooth samples having natural life accumulated color were divided over five groups: A. 9h light + 10h 6% H₂O₂ gel + 6h light & 6% H₂O₂ combined; B. 9h 6% H₂O₂ gel + 10h light + 6h light & 6% H₂O₂ combined; C. 11 h light & 6% H₂O₂ combined; D. 8.45h 25 %H₂O₂ gel + 10h of light only + 6h light & 25% H₂O₂ combined E. 10.45 h light & 25 %H₂O₂ combined. Blue light (456nm) was used at 190 mW/cm². Color change (ΔE) was measured over time, and reported after 48h color stabilization.

Results

Groups A, B and D reached saturation in the first phase (at 9h) at a ΔE of 4.3 ± 0.7, 4.9 ± 1.3 and 10.9 ± 2.2, respectively. Groups C and E achieved in the same time a significantly higher ΔE of 14.2 ± 1.7 and 15.6 ± 1.9, respectively. Subsequently adding the opposite single modality to groups A, B and D for 10h did reach an end stage at 8.1 ± 1.3, 8.8 ± 1.8 and 10.8 ± 1.4 ΔE, respectively. The final 6h treatment combining light and H₂O₂ showed in these groups a statistically significant step in ΔE reaching 12.9 ± 1.4, 10.7 ± 2.5 and 15.3 ± 1.7, respectively.

Conclusions

Blue light significantly increases bleaching rate and final achievable ΔE.

This sequential whitening study provides a first indication that this enhanced bleaching is the result of the hypothesized light mechanisms acting in parallel to hydrogen peroxide bleaching.

Clinical significance

This study shows that blue light can accelerate whitening, within the limits of an in-vitro model. The findings help the clinician explain to their patients that in light accelerated whitening the light not merely accelerates the bleaching process, but that it attacks more stain compounds than peroxide alone does.

Comparative Analysis of Shear Bond Strength of Composites to the Sodium Ascorbate Hydrogel-treated Bleached Enamel Surfaces: An In Vitro Analysis

Aim

To compare the shear bond strength of composites to the sodium ascorbate hydrogel-treated bleached enamel surfaces.

Materials and methods

Sixty-six extracted human maxillary first premolars were sectioned mesiodistally to obtain two nonocclusal surfaces (n = 132). The specimen in the experimental group (n = 80) were divided into four treatment groups depending upon bleaching protocols used: group I (10% FGM home bleach), group II (22% Pola Night home bleach), group III (37% light-activated in-office bleach Pola Office+), and group IV (35% Pola office in-office bleach without light activation). Specimens were subjected to the 1-minute application twice with sodium ascorbate hydrogel and were further divided into two subgroups “a” (acetone-based) and “b”(ethanol-based) depending upon the bonding agents used. The specimens of the control group (n = 52) were further divided into two treatment groups, that is, positive control and negative control. The specimens were tested using universal testing machine.

Results

The result of the present study revealed that the specimens bleached with 10% FGM home bleach showed the greatest shear bond strength and specimens bleached with 35% in-office bleach Pola Office showed the lowest shear bond strength.

Conclusion

A twice 1-minute application of sodium ascorbate hydrogel was effective to reverse the deleterious results of bleaching on enamel shear bond strength. Bonding agent containing acetone as a solvent (Prime and Bond NT) in this present study showed greater shear bond strength values than the bonding agent containing ethanol as a solvent (Adper Single Bond).

Statement of clinical relevance

The shear bond strength of composite restorative materials could be improved by applying sodium ascorbate gel to the bleached enamel surfaces.

How to cite this article

Pathak K, Kumar P, Choudhary A, et al. Comparative Analysis of Shear Bond Strength of Composites to the Sodium Ascorbate Hydrogel-treated Bleached Enamel Surfaces: An In vitro Analysis. Int J Clin Pediatr Dent 2021;14(6):741–747.

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.

Analysis of enamel structure and mineral density after different bleaching protocols using micro-computed tomography

OBJECTIVE

This study aims to investigate the effect of three different bleaching applications on structural integrity, mineral volume (MV) and density of the enamel by using micro-computed tomography (Micro-CT) and evaluate the colour effectiveness using CIEDE2000.

MATERIALS AND METHODS

Twenty-four maxillary premolar teeth were divided into three groups (n = 8) (group 1: 40% HP gel with erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser activation; group 2: 40% HP gel with diode laser activation; group 3: 16% CP gel). Bleaching protocols were applied and colour alteration was obtained. Data were calculated with CIEDE2000 before and after bleaching. A Micro-CT was used to scan the specimens before and after the bleaching application. Statistical analysis was performed by ANOVA.

RESULTS

No significant difference was observed between the groups for colour changes (p > .05). Micro-CT analysis showed significant differences in structural thickness, structural separation, mineral density and MV for the different ROIs before and after bleaching for all groups (p<.05).

CONCLUSIONS

All of the bleaching methods represented similar efficiency. However, bleaching with Er,Cr:YSGG laser was less harmful to enamel in comparison with other bleaching methods. The present results may be useful for establishing a numerical standard for the change in bleaching with laser systems in dental hard tissues.

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.

A review on dental whitening

OBJECTIVES

To provide a narrative review on vital dental whitening chemistry, toxicity and safety, vital dental whitening techniques, whitening systems, potential side effects of whitening and cyclic whitening using products with a range of concentrations and pH values. In addition, new developments and recommendations in the field of vital dental whitening will be presented to help clinicians understand the whitening process, its advantages, limitations, and the impact of whitening concentration and pH on enamel providing guidance in tailoring whitening treatments.

DATA

Data were gathered using the following keywords: dental whitening, roughness, hardness, sensitivity, hydrogen peroxide, whitening pH, whitening concentration, whitening chemistry, colour, and toxicity.

SOURCES

An electronic search was performed using PubMed and Scopus databases. Bibliographic material from papers reviewed was then used to find other relevant publications.

CONCLUSIONS

The effectiveness of vital dental whitening depends on many factors, such as the concentration/pH of the whitening agent, application duration, chemical additives, and re-mineralising agents used. Developing new whitening products and technologies such as nano-additives and alternative carrier systems is showing promising results, and might prove efficient in maximising whitening benefits by accelerating the whitening reaction and/or minimising expected reversible/irreversible enamel structural damage.

Effects of desensitizing products on the reduction of pain sensitivity caused by in-office tooth bleaching: a 24-week follow-up

Objective

To clinically assess the effect of desensitizing gels and dentifrices on the reduction in pain sensitivity and color variation during tooth bleaching.

Methodology

A total of 108 volunteers were randomly separated into the following groups of n=12: GT/S-glycerine and thickener/sucralose; NF/S-potassium nitrate and sodium fluoride/sucralose; NA/S-potassium nitrate and arginine/sucralose; GT/AC-glycerine and thickener/arginine and calcium carbonate; NF/AC-potassium nitrate and sodium fluoride/arginine and calcium carbonate; NA/AC-potassium nitrate and arginine/arginine and calcium carbonate; GT/PN-glycerine and thickener/potassium nitrate; NF/PN-potassium nitrate and sodium fluoride/potassium nitrate; and NA/PN-potassium nitrate and arginine/potassium nitrate. Sensitivity was assessed with the numerical analogue scale, and color variation (ΔE) was measured with a spectrophotometer. The sensitivity values obtained were subjected to a multivariate analysis of variance (MANOVA) and color variation values were subjected to a randomized analysis of variance (p<0.05).

Results

The NF/AC, NA/AC, NF/PN, and NA/PN groups presented lower sensitivity values and reduced sensitivity compared to those of the other groups throughout the clinical sessions. None of the groups showed sensitivity at the 24-week assessment. Statistically, no significant difference were observed in the color values among the groups four weeks after the beginning of bleaching (p=0.074). Additionally, the color assessment of all groups was statistically similar four weeks (p=0.084) and 24 weeks (p=0.118) after the beginning.

Conclusion

Our results indicate that adding NF/S, NA/S, NF/AC, and NA/AC desensitizers to tooth bleaching protocols reduces pain sensitivity without affecting its effectiveness.

Influence of Tooth Pigmentation on H2O2 Diffusion and Its Cytotoxicity After In-office Tooth Bleaching

Clinical Relevance

Pigments in tooth structures affect the diffusion of H2O2 through enamel and dentin. The bleaching methodology can be impacted.

SUMMARY

Objective: The aim of this study was to evaluate the influence of the presence of pigments in tooth structures on the trans-enamel and trans-dentin diffusion of hydrogen peroxide (H2O2) and its cytotoxicity after carrying out an in-office bleaching therapy.

Methods and Materials: A bleaching gel with 35% H2O2 was applied for 45 minutes (three times for 15 minutes) on enamel and dentin discs (n=6), either previously submitted to the intrinsic pigmentation protocol with a concentrated solution of black tea, or not, defining the following groups: G1, unbleached untreated discs (control 1); G2, unbleached pigmented discs (control 2); G3, bleached untreated discs; G4, bleached pigmented discs. The discs were adapted to artificial pulp chambers, which were placed in wells of 24-well plates containing 1 mL culture medium (Dulbecco’s modified Eagle’s medium [DMEM]). After applying the bleaching gel on enamel, the extracts (DMEM + components of bleaching gel that diffused through the discs) were collected and then applied on the cultured MDPC-23 odontoblast-like cells. Cell viability (methyl tetrazolium assay and Live & Dead, Calcein AM, and ethidium homodimer-1 [EthD-1] probes), the amount of H2O2 that diffused through enamel and dentin (leuco-crystal violet product), and the H2O2-mediated oxidative cell stress (SOx) and components of degradation were assessed (analysis of variance/Tukey; α=0.05).

Results: There was no significant difference between the groups G1 and G2 for all the parameters tested (p&gt;0.05). Reduction in the trans-enamel and trans-dentin diffusion of H2O2 occurred for G4 in comparison with G3. Significantly lower cell viability associated with greater oxidative stress was observed for G3 (p&lt;0.05). Therefore, in-office tooth bleaching therapy performed in pigmented samples caused lower cytotoxic effects compared with untreated samples submitted to the same esthetic procedure (p&lt;0.05).

Conclusion: According to the methodology used in this investigation, the authors concluded that the presence of pigments in hard tooth structures decreases the trans-enamel and trans-dentin diffusion of H2O2 and the toxicity to pulp cells of an in-office bleaching gel with 35% H2O2.

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

BACKGROUND

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

TYPES OF STUDIES REVIEWED

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

RESULTS

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

CONCLUSIONS AND PRACTICAL IMPLICATIONS

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

Violet LED for non-vital tooth bleaching as a new approach

Different light sources have been used during dental bleaching procedures. More recently, a violet LED system was introduced as a promising and viable light source, which is capable to promote dental bleaching without chemical agents, although this light source could be also associated to a bleaching agent. This case report aimed to present the association of a violet LED and a bleaching agent over a discolored non-vital tooth. After anamnesis, clinical and radiographic examinations, a dental bleaching protocol was proposed as follow: 15 applications of the violet LED during 60 s (Bright Max Whitening, MMOptics) with 30 s interval between them. Before the last 5 applications, 35% hydrogen peroxide gel (Whiteness HP Maxx, FGM) was applied inside the pulp chamber and on enamel surface of the tooth (vestibular and palatal surfaces) and then the last 5 irradiations were performed. Three sessions were performed, with 7-days interval. Color assessment using a VITA classical scale and VITA EasyShade® spectrophotometer was carried out. After dental bleaching, color changed (tooth 21) from A3.5 to B2. The protocol used in this case report showed to be satisfactory for the non-vital tooth bleaching.

Clinical Evaluation of In-Office Dental Bleaching Using a Violet Light-Emitted Diode

Objective: To clinically evaluate the effect of the violet light-emitted diode (LED) light (405-410 nm) associated to in-office dental bleaching with 35% carbamide peroxide, on tooth color change and sensitivity. Participant's satisfaction after treatment was also evaluated. Materials and methods: A total of 50 participants were selected and randomized into a treatment group (n = 25): G1-two bleaching sessions of 30 min each, with 7-day interval (D0 and D7); G2-two bleaching sessions (same protocol as G1) associated with violet LED light, 30 min each session. The color evaluation was performed before and after 7 days of the second session (D0 and D14); the medium third of buccal surface of canine and central incisor teeth were evaluated under VITA Shade Guide and spectrophotometry (subjective and objective). Tooth sensitivity was evaluated immediately after the treatment and after 48 h of each bleaching session (D0, D2, D7, and D9), and a self-perception questionnaire was applied on D14. Results: Data were subjected to nonparametric Mann-Whitney test and both canine and central incisor teeth presented color change. Group G2 showed significantly more change than G1. Fisher's exact test showed no statistically significant dental sensitivity differences between groups. Both groups reported a high level of satisfaction but chi-square test showed statistically higher satisfied patients with dental bleaching in G2 than G1. Conclusions: The violet LED light (405-410 nm) could improve dental bleaching effectiveness, without sensitivity increase.

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

AIM

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

Different light-activation systems associated with dental bleaching: a systematic review and a network meta-analysis

OBJECTIVES

A systematic review and a network meta-analysis were performed to answer the following research question: "Is there any light-activation protocol capable of improving color change efficacy when associated with an in-office bleaching gel in adults?"

MATERIAL AND METHODS

A search was performed in PubMed, Scopus, Web of Science, LILACS, BBO, Cochrane Library, and SIGLE without date and/or language restrictions in April 23, 2017 (updated on March 30, 2018). IADR abstracts (1990-2018), unpublished and ongoing trial registries, dissertations, and theses were also searched. Only randomized clinical trials conducted in adults that included at least one group treated with in-office dental bleaching with light activation were included. The risk of bias (RoB) was evaluated using the Cochrane Collaboration tool. A random-effects Bayesian-mixed treatment comparison (MTC) model was used to combine light-activated versus light-free in-office bleaching with direct light-free comparison trials. A meta-analysis with independent analysis (high- and low-concentrate hydrogen peroxide [HP]) was conducted for color change (∆E*, ∆SGU).

RESULTS

After the removal of duplicates, title, and abstract screening, 28 studies remained. Nine were considered to be at a low RoB, five were at a high RoB, and the remaining were at an unclear RoB. The MTC analysis showed no significant difference in color change (ΔE* and ΔSGU) between light-activation protocols and light-free in-office bleaching, regardless of the HP concentration in the efficacy of the bleaching.

CONCLUSION

No type of light-activated in-office bleaching was superior to light-free in-office bleaching for both high- and low-concentrate in-office bleaching gels (PROSPERO-CRD42017078743).

CLINICAL RELEVANCE

Although many times dental professionals use "laser whitening" as a form of marketing, this study confirmed that no type of light-activation for in-office bleaching can improve the bleaching efficacy.

Clinical Study of Bleaching Gel Storage Temperature on Tooth Color and Sensitivity

OBJECTIVE

The objective of this triple-blind, split-mouth, randomized clinical trial was to evaluate the bleaching efficacy and tooth sensitivity of an in-office bleaching agent submitted to different storage temperatures (room temperature at 21.04°C±3.13°C or refrigeration at 5°C).

METHODS AND MATERIALS

Thirty volunteers were selected who had central incisors with color A2 or higher. The volunteers' maxillary hemi-arches received either the bleaching treatment with room temperature or refrigerated storage temperatures (two sessions of 3×15 minutes, one-week interval). Color variation was evaluated by subjective (Vita Classic and Vita Bleachedguide) and objective methods (Vita Easyshade spectrophotometer). Tooth sensitivity was evaluated with the visual analog scale (0-10) and the numerical rating scale (five points). The consistency of bleaching gels was evaluated by flow test, and pH was measured, both in triplicate. Color variation (SGU) and ΔE were analyzed by paired t-test (α=0.05). The absolute risk of pain was assessed by McNemar test (α=0.05), data from the numerical rating scale by the Wilcoxon signed-rank test (α=0.05), and visual analog scale by paired t-test. Comparison between the times within each group was analyzed by Friedman test. Gel consistency and pH were analyzed by one-way analysis of variance and Tukey post-test.

RESULTS

Regarding the absolute risk of tooth sensitivity, no significant difference was observed between the groups. The relative risk for tooth sensitivity was 1.13 (95%, confidence interval 0.70-1.82). Both tooth sensitivity scales were statistically similar. The results of the subjective evaluation (Vita Classic: p=0.73, Vita Bleachedguide: p=1.00) and the objective evaluation (p=1.00) of bleaching efficacy corresponded to the hypothesis of equality between groups after bleaching. Both pH values were around 7, and for the consistency test, there were significant differences between the groups (p=0.002).

CONCLUSIONS

Storage temperature of the analyzed in-office bleaching agent had no influence on tooth color effectiveness and tooth sensitivity.

Laser Effects on the Prevention and Treatment of Dentinal Hypersensitivity: A Systematic Review

Introduction: Dentinal hypersensitivity (DH) is an acute intensive tooth pain which can lead to dental annoyances during eating and drinking. Stimulating exposed dentinal tubules by either kind of thermal, tactile, chemical and/or osmotic stimuli is believed to be the cause of this pain. It is hypothesized that dentinal tubules' orifice occlusion (DOO) can help relieve such dental irritations. Thus, this systematic review was conducted to evaluate the effectiveness of laser application as a prevention and treatment modality on DH reduction. Methods: Electronic databases (MEDLINE, SCOPUS) were searched among randomized clinical trials from January 2007 to December 2016. The extraction of data and quality assessments were carried out by different independent observers. Results: A total of 499 items were found of which3 9 relevant articles were extracted. The profound findings proved lasers' effectiveness as a treatment of DH. Although some of the researches reported no significant difference between laser and other desensitizing agents, most of the studies suggested that better results (both rapid and long-lasting) were obtained in combined modalities. Furthermore, the preventive role of this new technology has been emphasized as well. Nd-YAG (neodymium-doped yttrium aluminum garnet) and diode lasers reduce DH after bleaching. Lasers can also protect cervical restorations from DH due to tubular occlusion. Moreover, it is suggested to apply lasers in relief of DH following scaling and root planning. Nevertheless, a few researchers dispute its beneficence as a result of placebo effect. Conclusion: The results obtained from several studies in the present review revealed that the application of lasers is effective not only in terms of treatment of DH, but also in the prevention of this intensive tooth pain. Among various types of lasers, the application of Nd:YAG laser has shown the best results in DH treatment.

Effect of lights with various wavelengths on bleaching by 30% hydrogen peroxide

The objective of this study was to evaluate the bleaching effect of light sources with various wavelengths using 30% hydrogen peroxide (HP) in vitro. The hematoporphyrin-stained paper was bleached with HP and irradiated for 10 min using LED light sources with 265, 310, 365, 405, or 450 nm respectively. In control group, HP was applied for 10 min without light irradiation. The bleaching procedure was repeated two times. The L*a*b* values of the samples before bleaching and after each bleaching step were measured using a colorimeter. Color changes of specimens were then calculated and statistically analyzed. There was an interaction between light sources and time of irradiation in the color change (p < 0.05). Time and light sources significantly affected ΔE and ΔL (p < 0.05). The light source of 256 nm showed the highest bleaching effect over time followed by that of 310 nm, which were statistically different from other groups (p < 0.001). The 365 nm, 450 nm groups, and control group showed low bleaching effect visually with no significant differences in ΔE and ΔL (p > 0.05). It was concluded that the wavelengths of the light sources affected the bleaching by HP. The 310-nm light can be a potential source for bleaching.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

CLINICAL SIGNIFICANCE

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

Effectiveness of Light Sources on In-Office Dental Bleaching: A Systematic Review and Meta-Analyses

OBJECTIVE

A systematic review and meta-analyses were performed to evaluate the efficacy of tooth color change and sensitivity of teeth following in-office bleaching with and without light gel activation in adult patients.

METHODS

This review was registered at PROSPERO (CRD 42017060574) and is based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Electronic systematic searches of PubMed/MEDLINE, Web of Science, and the Cochrane Library were conducted for published articles. Only randomized clinical trials among adults that compared in-office bleaching with and without light activation with the same bleaching gel concentrations were selected. The outcomes were tooth color change and tooth sensitivity prevalence and intensity.

RESULTS

Twenty-three articles from 1054 data sources met the eligibility criteria. After title and abstract screening, 39 studies remained. Sixteen studies were further excluded. Twenty-three studies remained for qualitative analyses and 20 for meta-analyses of primary and secondary outcomes. No significant differences in tooth color change or tooth sensitivity incidence were found between the compared groups; however, tooth sensitivity intensity decreased when light sources were applied.

CONCLUSION

The use of light sources for in-office bleaching is not imperative to achieve esthetic clinical results.

Tooth sensitivity with a desensitizing-containing at-home bleaching gel-a randomized triple-blind clinical trial

OBJECTIVES

Desensitizing agents are usually included in the composition of bleaching agents to reduce bleaching-induced tooth sensitivity (TS). This randomized clinical trial (RCT) evaluated the risk and intensity of TS and color change after at-home bleaching with a desensitizing-containing (3% potassium nitrate and 0.2% sodium fluoride) and desensitizing-free 10% carbamide peroxide (CP) gel (Whiteness Perfect, FGM).

METHODS

A triple-blind, within-person RCT was conducted on 60 caries-free adult patients. Each participant used the gel in a bleaching tray for 3 h daily for 21 days in both the upper and lower dental arches. The absolute risk and intensity of TS were assessed daily through the 0-10 VAS and NRS scale for 21 days. Color change was recorded using shade guides (Vita Classical and Vita Bleachedguide) and the Easyshade spectrophotometer at baseline, weekly and 30 days after the end of the bleaching. The risk and intensity of TS were evaluated by the McNemar and Wilcoxon Signed Rank tests, respectively. Color change (ΔSGU and ΔE) were evaluated by the Mann-Whitney test and a paired t-test, respectively (α = 0.05).

RESULTS

No difference in the TS and color change was observed (p > 0.05).

CONCLUSIONS

The incorporation of potassium nitrate and sodium fluoride in 10% carbamide peroxide at-home bleaching gel tested in this study did not reduce the TS and did not affect color change (RBR-4M6YR2).

Effectiveness of LED/Laser Irradiation on In-Office Dental Bleaching after Three Years

The present in vivo randomized, triple-blinded, and split-mouth clinical study evaluated the effectiveness of a hybrid light (HL) source on the color change, stability, and tooth sensitivity in patients submitted to different in-office bleaching techniques. Twenty volunteers were divided into two groups and four subgroups. A split-mouth design was conducted to compare two in-office bleaching techniques (with and without light activation): 35% Lase Peroxide Sensy (LPS) + HL: 35% hydrogen peroxide (HP) + HL; 35% LPS: 35% HP; 25% LPS + HL: 25% HP + HL; and 35% Whiteness HP (WHP): 35% HP. For the groups activated with HL, the HP was applied on the enamel surface three consecutive times using a 3 × 2-minute protocol (three HL activations for two minutes each, with a 30-second interval for a total of seven minutes and 30 seconds) for each gel application, totaling 22 minutes and 30 seconds. For the other groups, HP was applied 3 × 15 minutes, totaling 45 minutes. A spectrophotometer was used to measure the color change (ΔE) before the treatment and 24 hours, one week, and one, 12, and 36 months after. A visual analog scale was used to evaluate the tooth sensitivity before the treatment, immediately following treatment, 24 hours, and one week after. Analysis of variance, Tukey's, Kruskall-Wallis, and Wilcoxon tests, all with α = 0.05 were performed. Statistical analysis did not reveal any significant differences (ΔE) between the in-office bleaching techniques with or without HL in the periods evaluated; the activation with HL required 50% less time to achieve such results. The groups without HL presented statistical differences for ΔE when comparing 24 hours with the other follow-up times (intergroup) and an increase in tooth sensitivity in the initial periods. All techniques and bleaching agents were effective on bleaching during a 36-month evaluation of color stability. The groups activated with HL presented lower sensitivity and required a lower activation time.

In-office dental bleaching with light vs. without light: A systematic review and meta-analysis

OBJECTIVE

A systematic review and meta-analysis were performed to answer the following research question: Does light-activated in-office vital bleaching have a greater whitening efficacy and higher tooth sensitivity (TS) in comparison with in-office vital bleaching without light when used in adults?

DATA AND SOURCE

Only randomized clinical trials (RCTs) involving adults who had in-office bleaching with and without light activation were included. Controlled vocabulary and keywords were used in a comprehensive search for titles and abstracts in PubMed, and this search was adapted for Scopus, Web of Science, LILACS, BBO, Cochrane Library, and SIGLE without restrictions in May 2016 and was updated in August 2017. IADR abstracts (1990-2016), unpublished- and ongoing-trial registries, dissertations, and theses were also searched. The risk-of-bias tool of the Cochrane Collaboration was used for quality assessment. The quality of the evidence was rated using the Grading of Recommendations: Assessment, Development, and Evaluation approach. Through the use of the random effects model, a meta-analysis with a subgroup analysis (low and high hydrogen peroxide concentration) was conducted for color change (ΔE*, ΔSGU) as well as the risk and intensity of TS.

STUDY SELECTION

We retrieved 6663 articles, but after removing duplicates and non-relevant articles, only 21 RCTs remained. No significant difference in ΔE*, ΔSGU, and risk and intensity of TS was observed (p > .05). For ΔE and risk of TS, the quality of the evidence was graded as moderate whereas the evidence for ΔSGU and intensity of TS was graded as very low and low, respectively.

CONCLUSION

Without considering variations in the protocols, the activation of in-office bleaching gel with light does not seem to improve color change or affect tooth sensitivity, regardless of the hydrogen peroxide concentration. (PROSPERO - CRD42016037630).

CLINICAL RELEVANCE

Although it is commercially claimed that in-office bleaching associated with light improves and accelerates color change, this study did not confirm this belief for in-office bleaching gels with either high or low levels of hydrogen peroxide.

Evaluation of several clinical parameters after bleaching with hydrogen peroxide at different concentrations: A randomized clinical trial

OBJECTIVE

This randomized double-blind clinical trial compared tooth sensitivity (TS), bleaching efficacy, and cytokine levels after applying in-office bleaching treatments containing 15% and 35% hydrogen peroxide (HP15% and HP35%, respectively).

METHODS

Twenty-five volunteers were randomly assigned to receive HP15% or HP35% treatment. The bleaching agent was applied in three 15-min applications per session. Two bleaching sessions were separated by a 1-week interval. The participants scored TS using a visual analog scale and numerical rating scale. Bleaching efficacy was determined by subjective and objective methods. Gingival crevicular fluid was collected from three jaws sites per patient for the analysis of fluid volume. Flow cytometry was used to analyze gingival crevicular fluid levels of interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-10, tumor necrosis factor, and interferon-gamma. All measurements were obtained before and after bleaching. All data were statistically analyzed (α=0.05).

RESULTS

The absolute risk and intensity of TS was higher for HP35% than for HP15% (p>0.002). One month post-bleaching, HP35% produced more bleaching than HP15% (p=0.02). However patient perception (p=0.06) and patient satisfaction (p=0.53) with regard to bleaching were not significantly different. No significant differences existed in the gingival fluid volume (p>0.38) or in any cytokine level (p>0.05) for either HP concentration.

CONCLUSION

Treatment: with HP35% is more effective than HP15%, but generates a greater risk and intensity of TS. No inflammatory changes occurred despite the difference in the HP concentrations.

CLINICAL SIGNIFICANCE

Hydrogen peroxide at a lower concentration (e.g., 15%) should be considered a good treatment alternative for in-office bleaching because the higher concentration for in-office bleaching generates a greater risk and intensity of TS for patients.

Randomized clinical trials of dental bleaching - Compliance with the CONSORT Statement: a systematic review

We reviewed the literature to evaluate: a) The compliance of randomized clinical trials (RCTs) on bleaching with the CONSORT; and b) the risk of bias of these studies using the Cochrane Collaboration risk of bias tool (CCRT). We searched the Cochrane Library, PubMed and other electronic databases, to find RCTs focused on bleaching (or whitening). The articles were evaluated in compliance with CONSORT in a scale: 0 = no description, 1 = poor description and 2 = adequate description. Descriptive analyses of the number of studies by journal, follow-up period, country and quality assessments were performed with CCRT for assessing risk of bias in RCTs. 185 RCTs were included for assessment. More than 30% of the studies received score 0 or 1. Protocol, flow chart, allocation concealment and sample size were more critical items, as 80% of the studies scored 0. The overall CONSORT score for the included studies was 16.7 ± 5.4 points, which represents 52.2% of the maximum CONSORT score. A significant difference among journal, country and period of time was observed (p < 0.02). Only 7.6% of the studies were judged at "low" risk; 62.1% were classified as "unclear"; and 30.3% as "high" risk of bias. The adherence of RCTs evaluating bleaching materials and techniques to the CONSORT is still low with unclear/high risk of bias.

Effect of acidity of in-office bleaching gels on tooth sensitivity and whitening: a two-center double-blind randomized clinical trial

OBJECTIVES

The study aimed to compare the tooth sensitivity (TS) and bleaching efficacy of two hydrogen peroxide gels with different pHs (acid pH [Pola Office, SDI] and the neutral pH [Pola Office+, SDI]) used for in-office bleaching.

MATERIALS AND METHODS

Fifty-four patients from Brazil and Chile, with right superior incisor darker than A2, were selected for this double-blind, split-mouth randomized trial. Teeth were bleached in two sessions, with 1-week interval. Each session had three applications of 8 min each, according to the manufacturer's instructions. The color changes were evaluated by subjective (Vita Classical and Vita Bleachedguide) and objective (Easy shade spectrophotometer) methods. Participants recorded TS with 0-10 visual analog scale. Color change in shade guide units (SGU) and ΔE was analyzed by Student's t test (α = 0.05). The absolute risk and intensity of TS were evaluated by McNemar's test and Wilcoxon-paired test, respectively (α = 0.05).

RESULTS

All groups achieved the same level of whitening after 30 days of clinical evaluation. The use of a neutral in-office bleaching gel significantly decreases the absolute risk of TS (28%, 95% CI 18-41) and intensity of TS when compared to the acid bleaching gel (absolute risk of 50%, 95% CI 37-63).

CONCLUSION

The use of a neutral in-office bleaching agent gel produced the same whitening degree than an acid bleaching gel but with reduced risk and intensity of tooth sensitivity.

CLINICAL SIGNIFICANCE

Clinicians should opt to use in-office bleaching with a neutral gel than an acid product because the former causes a significant lower risk and intensity of tooth sensitivity.