Effect of toothbrushing with conventional and whitening dentifrices on monolithic zirconia after finishing procedures.

PURPOSE: To evaluate the effect of toothbrushing with conventional and whitening dentifrices on the color difference (ΔE00), gloss (Δgloss), and surface roughness (SR) of stained stabilized zirconia with 5 mol% of yttrium oxide (5Y-TZP) after polishing or glazing. METHODS: Specimens were divided into four groups (n=20): C (control), S (staining), SG (staining and glazing) and SP (staining and polishing). 50,000 toothbrushing cycles were performed with conventional (n=10) and whitening (n= 10) dentifrice slurries. The ΔE00 and Δgloss were measured using a spectrophotometer and CIEDE2000 system while SR was measured by laser confocal microscope. The ΔE00 and Δgloss data were analyzed using 2-way ANOVA, and SR data were analyzed using the linear repeated measures model, with Bonferroni's complementary test (α= 0.05). RESULTS: The ΔE00 values were beyond the acceptability threshold and no differences were found among the groups. There was no difference among groups to Δgloss after toothbrushing with conventional dentifrice while SP presented the highest values of Δgloss after toothbrushing with whitening dentifrice. Conventional dentifrice decreased the SR of stained groups and whitening dentifrice decreased SR of S and SG. The toothbrushing with conventional and whitening dentifrices promoted color difference, but did not impair gloss and surface roughness of stained 5Y-TZP. CLINICAL SIGNIFICANCE: Monolithic zirconia has been routinely used for esthetic restorations, however the type of finishing procedures that is carried out on it must be taken into consideration, in addition to the fact that brushing can influence the color difference of the material as well as interfere with surface roughness and gloss.

Over-the-counter products in tooth bleaching: A scoping review.

OBJECTIVE: To map and summarize the current scientific evidence concerning the active ingredients, effectiveness, and adverse effects of over-the-counter (OTC) bleaching products. DATA AND SOURCE: This study was conducted according to the PRISMA-ScR guidelines for scoping reviews and registered on the Open Science Framework platform. STUDY SELECTION: Database searches were conducted in PubMed/MEDLINE, Embase, and Scopus up to January 2024. All in vitro, in situ, and clinical studies evaluating the effectiveness and adverse effects of OTC bleaching products were included. A descriptive analysis of the included studies was performed. RESULTS: A total of 88 studies were included. Most of them were in vitro studies (n = 49), followed by randomized clinical trials (n = 28). The main OTC bleaching products identified were whitening or stain-removing toothpastes (n = 42), followed by whitening strips (n = 39). Most clinical studies indicate that whitening strips are effective in improving tooth color and providing whitening benefits. In contrast, the bleaching effectiveness of toothpastes, mouth rinses and whitening trays was mainly supported by in vitro studies. The main adverse effects associated with OTC bleaching agents were tooth sensitivity and gingival irritation. CONCLUSION: A wide variety of OTC bleaching products is available for consumer self-administered use. Clinical studies have mainly confirmed the bleaching effectiveness of whitening strips, while the validation for toothpastes, mouth rinses and whitening trays has mainly relied on in vitro studies. Nevertheless, the use of OTC bleaching products may result in adverse effects, including tooth sensitivity, gingival irritation, and enamel surface changes. CLINICAL SIGNIFICANCE: Some over-the-counter bleaching products may have whitening properties supported by clinical studies, particularly those containing hydrogen or carbamide peroxide. Nonetheless, clinicians must be aware of the potential risks associated with excessive self-administration of these products, which may result in adverse effects.

At-home bleaching versus whitening toothpastes for treatment of tooth discoloration: a cost-effectiveness analysis.

OBJECTIVES: This study aimed to analyze the cost-effectiveness of whitening toothpastes and at-home bleaching for the treatment of tooth discoloration. METHODOLOGY: A cost-effectiveness economic analysis was conducted, and eight randomized clinical trials were selected based on the whitening agent product used: blue covarine dentifrices (BCD), hydrogen peroxide dentifrices (HPD), dentifrices without bleaching agents (CD, negative control), and 10% carbamide peroxide (CP10, positive control) for at-home bleaching. The consumer/patient perspective was adopted, macro-costing techniques were used and a decision tree model was performed considering the costs in the American and Brazilian markets. The color change evaluation (ΔE*ab) was used to calculate the effectiveness of tooth bleaching. A probabilistic analysis was performed using a Monte Carlo simulation and incremental cost-effectiveness ratios were obtained. RESULTS: CP10 resulted in the highest cost-effectiveness compared to the use of dentifrices in both markets. In Brazil, HPD was more cost-effective than BCD and CD. In the US, the increased costs of HPD and BCD did not generate any whitening benefit compared to CD. CONCLUSIONS: CP10 was more cost-effective than BCD and HPD for tooth bleaching from the perspectives of the Brazilian and American markets. Decision-making should consider the use of CP10 for treating tooth discoloration.

EFFECTS OF PROFESSIONAL ORAL HYGIENE AND TEETH WHITENING ON THE MICROELEMENT COMPOSITION OF ENAMEL.

OBJECTIVE: Aim: The objective of this study is to investigate the impact of professional teeth cleaning and the substances used in modern dentistry for whitening on the microelement composition of tooth enamel. PATIENTS AND METHODS: Materials and Methods: To study the morphology and microelement composition of the enamel, scanning electron microscopy was performed using the MiraLM microscope equipped with a Schottky field emission electron gun from Tescan. RESULTS: Results: A comparative analysis between the areas subjected to mechanical cleaning and those where it was not applied revealed a significant difference in the research results, particularly in carbon, which changed from 25.16±1.04 to 32.02±1.8. An analysis of the enamel's chemical composition before and after whitening revealed a decrease in carbon from 45.91±1.20 to 42.46±1.74. The change in phosphorus content was determined to be from 9.77±0.39 to 9.56±0.75. A decrease in calcium from 15.96±0.64 to 15.21±1.22 and magnesium from 0.07±0.01 to 0.01±0.01 was also observed. CONCLUSION: Conclusions: Professional dental hygiene does not have a direct impact on the microelement composition of enamel, such as the levels of calcium, phosphorus, fluoride, and other microelements. However, it can have an indirect and temporary influence due to the use of abrasive materials that affect dental deposits, pellicle, and the surface layer of enamel. Teeth whitening can affect the microelement composition of enamel, but these changes are mostly temporary and associated with processes of demineralization/ remineralization and oxygenation.

Dental aesthetic perception of patients submitted to activated charcoal-based bleaching agents: A randomized clinical trial.

OBJECTIVE: To evaluate the effects of activated charcoal-based products used in two presentation forms (powder or toothpaste), compared to 10 % carbamide peroxide and conventional toothpaste on aesthetic perception and psychosocial impact before and after treatment. METHODS: Fifty-six participants were divided into 4 experimental groups (n = 14). Activated charcoal-based powder (PW); Activated charcoal-based dentifrice (AC); Conventional fluoride toothpaste (CD) and 10 % carbamide peroxide (CP). All products were used for 14 days. Psychosocial impact on dental esthetics (PIDAQ), oral health impact profile (OHIP- Esthetics) and orofacial esthetics scale (OES) questionnaires were applied before and after treatment. Descriptive and exploratory data analyses were performed and analyzed using linear mixed models for repeated measures over time considering significance level of α = 0.05. RESULTS: For PIDAQ, the CP group showed significant decrease in psychological impact, aesthetic perception domains and overall score, while in the PW group, there was only a significant decrease in the psychological impact domain. Decrease in OHIP was observed for the functional limitation domain scores for treatments with CP and PW, in the psychological discomfort domain, decrease was observed for all groups, while for the OES questionnaire, significant increase in the color domain was observed for the CP group. CONCLUSION: Activated charcoal-based products showed lower scores in all questionnaires when compared with carbamide peroxide; thus, charcoal-based products promoted lower impact on quality of life and aesthetic perception. CLINICAL RELEVANCE: In this randomized clinical trial, charcoal-based OTC products had inferior quality of life and aesthetic perception results compared to conventional carbamide peroxide bleaching.

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.

Evaluation of Enamel Surfaces Treated with a Desensitizing Agent Containing CPP-ACP Before or After In-Office Bleaching.

PURPOSE: To evaluate the effects of desensitizing MI Varnish (GC America) applied before or after bleaching on the mineral component of enamel and surface topography. MATERIALS AND METHODS: The coronal portions of 10 freshly extracted bovine teeth were segmented for a total of 40 specimens. Enamel specimens obtained from each tooth were randomly divided into four groups (n = 10): Group A = no bleaching; Group B = bleaching with 40% hydrogen peroxide (HP); Group C = MI Varnish applied before bleaching; and Group D = MI Varnish applied after bleaching. The calcium (Ca) and phosphorus (P) levels of the specimens in each group were determined by energy dispersive spectroscopy (EDS). Morphologic changes were observed using scanning electron microscopy (SEM). One-way ANOVA and Tukey HSD tests were used for statistical analyses (α = .05). RESULTS: The mean Ca content of Group B was significantly lower than those of Groups A, C, and D (P < .05). The mean Ca content of Group C was significantly lower than that of Group A (P < .05). There was no significant difference in Ca content between the other groups (P > .05). The mean P content of Group A was significantly higher than those of Groups B to D (P < .05). There was no significant difference in P content between Groups B to D (P > .05). CONCLUSIONS: Application of MI Varnish before or after in-office bleaching was effective in reducing mineral loss. However, applying MI Varnish after bleaching was more effective.

Prognosis in home dental bleaching: a systematic review.

OBJECTIVES: The aim of this systematic review was to evaluate the prognosis of at-home dental bleaching using low concentration bleaching products. MATERIALS AND METHODS: This review was conducted was performed following the recommendations of the 2020 PRISMA statement and was registered in the International Prospective Register of Systematic Reviews (PROSPERO-CRD42022360530). The PICO question was "What is the prognosis of home teeth whitening treatment?". An advanced electronic search was made in three databases: PubMed, Web of Science, and Embase. RESULTS: The database search led to the retrieval of 225 articles. After elimination of duplicate references, the titles and abstracts of the articles were analyzed with respect to the eligibility criteria, and 24 studies were included for the development of the systematic review. CONCLUSIONS: Most authors state that the color remains stable between 1 and 2.5 years regardless of the type of bleaching agent or the forms of administration, and color stability in cases of severe discolorations presents a higher degree of recurrence. CLINICAL RELEVANCE: Given the growing demand for dental cosmetic treatments, the following systematic review may aid the clinician's continuing education and evidence-based practice by providing knowledge on the field of at-home dental bleaching agents and their long-term effects.

Comparative Clinical Study of Two Tooth Whitening Protocols.

This study aimed to clinically evaluate the effectiveness of two different at-home whitening protocols and to determine which is more effective: applying the whitening gel (16% carbamide peroxide) every 24 hours (Group A) or every 48 hours (Group B) for 2 weeks. Group C received a placebo gel (glycerin) without peroxide, which was applied every 24 hours for 2 weeks. The differences in terms of tooth sensitivity were also analyzed. A sample of 60 patients was divided into three groups of 20 patients. To compare the groups, color measurements were made using a spectrophotometer, and Student t test was used for independent samples. The confidence level was set at 95% (P ≤ .05). No statistically significant differences were found between Groups A and B (P > .05). The study concluded that 16% carbamide peroxide was equally effective when applied with either protocol and obtained the same results, but the 48-hour application protocol produced less sensitivity than the 24-hour application protocol.

One-year clinical observation of the effect of internal bleaching on pulpless discolored teeth.

OBJECTIVES: This study aimed to observe the color rebound and rebound rates of non-pulp discolored teeth within 1 year after routine internal bleaching to guide clinical practice and prompt prognosis. METHODS: In this work, the efficacy of bleaching was observed in 20 patients. The color of discolored teeth was measured by using a computerized colorimeter before bleaching; immediately after bleaching; and at the 1st, 3rd, 6th, 9th, and 12th months after bleaching. The L*, a*, and b* values of the color of cervical, mesial, and incisal parts of the teeth were obtained, and the color change amounts ΔE*, ΔL*, Δa*, and Δb* were calculated. The overall rebound rate (P*) and the color rebound velocity (V*) were also analyzed over time. RESULTS: In 20 patients following treatment, the average ΔE* of tooth color change was 14.99. After bleaching, the neck and middle of the teeth ΔE* and ΔL* decreased in the 1st, 3rd, 6th, 9th, and 12th months, and the differences were statistically significant. Meanwhile, from the 9th month after bleaching, the rebound speed was lower than that in the 1st month, and the difference was statistically significant. The incisal end of the tooth ΔE* and ΔL* decreased in the 6th, 9th, and 12th months after bleaching, and the differences were statistically significant. No significant difference was found in the rebound speed between time points. However, this rate settled after the 9th month, with an average color rebound rate of 30.11% in 20 patients. CONCLUSIONS: The results indicated that internal bleaching could cause a noticeable color change on pulpless teeth. The color rebound after bleaching was mainly caused by lightness (L*), which gradually decreased with time, and it was slightly related to a* and b*. The color of the teeth after internal bleaching rebounded to a certain extent with time, but the color rebound speed became stable from the 9th month. Clinically, secondary internal bleaching can be considered at this time according to whether the colors of the affected tooth and the adjacent tooth are coordinated and depending on the patient's needs.

The Efficacy of At-home, In-office, and Combined Bleaching Regimens: A Randomized Controlled Clinical Trial.

OBJECTIVE: The aim of this study was to compare the clinical efficacy of at-home, in-office, and combined bleaching regimens. METHODS: Forty-eight participants were recruited and randomly divided into four groups based on the bleaching regimen (n=12) as follows: 1) at-home bleaching using 10% carbamide peroxide (Opalescence PF 10%, Ultradent) for 14 days (HB); 2) two sessions of in-office bleaching using 40% hydrogen peroxide (Opalescence BOOST PF 40%, Ultradent) with a one-week interval (OB); 3) one session of in-office bleaching followed by at-home bleaching for seven days (OHB); and 4) at-home bleaching for seven days followed by one session of in-office bleaching (HOB). Tooth color was measured using a spectrophotometer (Easyshade, Vita ZahnFabrik) at baseline (T0), day 8 (T1), day 15 (T2), and day 43 (T3, four weeks after the end of the bleaching treatment). The color data were calculated using the CIEDE2000 (ΔE00) and whiteness index for dentistry (WID) formulas. Tooth sensitivity (TS) was recorded using a visual analogue scale (VAS) for 16 days. Data were analyzed by one-way analysis of variance (ANOVA) and the Wilcoxon signed-rank test (α=0.05). RESULTS: All bleaching regimens resulted in a significant increase in WID values (all p<0.05), while no significant differences in WID and ΔWID values were found among the different groups at each time point (all p>0.05). Significant differences in ΔE00 values were observed between T1 and T3 for all groups (all p<0.05), while no significant differences in ΔE00 values were found among the different groups at any time point (all p>0.05). Significantly lower TS values were observed in the HB group than in the OB and HOB groups (p=0.006 and p=0.001, respectively). CONCLUSIONS: All bleaching regimens resulted in great color improvement, and different regimens led to similar color changes at any of the evaluation time points. The sequence of treatments applying in-office bleaching or at-home bleaching did not affect the bleaching efficacy. The in-office bleaching and combined bleaching regimens yielded a higher intensity of TS than did at-home bleaching.

Evaluation of Different Protocols with 4% Hydrogen Peroxide in Bleaching Efficacy and Tooth Sensitivity - A Single-blind, Randomized Clinical Trial.

OBJECTIVES: To compare the bleaching efficacy and tooth sensitivity (TS) of 4% hydrogen peroxide (HP) in adults using a continuous or fractioned protocol. METHODS AND MATERIALS: A single-blind randomized controlled trial with a parallel design was conducted. Eighty-six patients with upper canines A2 or darker were submitted to bleaching with 4% HP gel for three weeks after random allocation into the fractioned protocol (two 30-minute daily applications) or continuous protocol (single one-hour application). We evaluated the color change at baseline, weekly, and 30 days after the bleaching using Vita Classical and Vita Bleachedguide using the units of shade guides (SGU) and by spectrophotometer using CIELab 1976 (ΔEab) and CIEDE 2000 formulas (ΔE00), as well as Whiteness Index (ΔWID). We assessed the absolute risk of TS with a visual analog scale (VAS) and numeric rating scale (NRS). Color changes in each recall were compared with the Student t-test. The risk of TS was evaluated by the Chi-square test, and the intensity by Mann-Whitney test (NRS) and Student t-test (VAS). RESULTS: The mean difference for the ΔSGU Vita Classical (0.5; 95% CI: -0.5 to 1.5), ΔSGU Vita Bleachedguide (-0.4; 95% CI: -1.5 to 0.7), ΔEab (1.4; 95% CI: -0.1 to 2.9), ΔE00 (0.6; 95% CI: -0.4 to 1.6), and ΔWID (-3.2; 95% CI: -7.3 to 0.9) after three weeks of bleaching was not clinically or statistically significant (p>0.10). The absolute risk of TS was 44% (95% CI: 30-58%) and 46% (95% CI: 32-61%) in the fractioned and continuous protocols, respectively (RR=1.0; 95% CI: 0.6 to 1.5; p>0.91). CONCLUSION: A fractioned bleaching protocol with 4% HP (30 minutes twice daily) did not increase the whitening degree nor affect the risk and intensity of TS when compared with the one-hour continuous protocol.

A systematic scoping review of color evaluation methods of recently published tooth bleaching clinical trials.

PURPOSE: This systematic scoping review aimed to survey the literature to answer the following questions: which instruments were used to measure the color change; which teeth were assessed for color; what was the follow-up period, and in which country was the recently published tooth bleaching clinical trial performed? METHODS: This research was registered in the Open Science Framework. The following databases were searched: PubMed, Scopus, Web of Science, EMBASE, Cochrane Library, and LILACS. Randomized clinical trials evaluating tooth bleaching with color change analysis, published between 2021 and 2017, were included. The data extracted from included studies were analyzed using a qualitative and descriptive analysis. RESULTS: 106 articles were analyzed. Most studies used only ΔEab to measure the color change (10.4%), assessed the color change in the maxillary central incisors (45.3%), and included a one-month follow-up (25.4%). The published papers were mostly from research performed in Brazil (51.9%). Many methods have been used in the tooth bleaching clinical trials examined, and a wide variety of instruments used to measure the color change was observed. CLINICAL SIGNIFICANCE: The large variation in the methodology criteria of most recent tooth bleaching clinical trials makes data comparison difficult among different studies and raises the need for a guideline for tooth bleaching clinical studies.

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

BACKGROUND: Topical application of calcium-containing bioactive desensitizers (CBs) has been used to minimize bleaching-induced tooth sensitivity (TS). This study answered the research question "Is the risk of TS lower when CBs are used with dental bleaching in adults compared with bleaching without desensitizers?" TYPES OF STUDIES REVIEWED: The authors included randomized clinical trials comparing topical CB application with a placebo or no intervention during bleaching. Searches for eligible articles were performed in MEDLINE via PubMed, Cochrane Library, Brazilian Library in Dentistry, Latin American and Caribbean Health Sciences Literature, Scopus, Web of Science, Embase, and gray literature without language and date restrictions and updated in September 2022. The risk of bias was evaluated using Risk of Bias Version 2.0. The authors conducted meta-analyses with the random-effects model. The authors assessed heterogeneity with the Cochrane Q test, I2 statistics, and prediction interval. The authors used the Grading of Recommendations Assessment, Development and Evaluation approach to assess the certainty of the evidence. RESULTS: After database screening, 22 studies remained, with most at high risk of bias. No difference in the risk of TS was detected (risk ratio, 0.95; 95% CI, 0.90 to 1.01; P = .08, low certainty). In a visual analog scale, the intensity of TS (mean difference, -0.98; 95% CI, -1.36 to -0.60; P < .0001, very low certainty) was lower for the CB group. The color change was unaffected (P > .08). PRACTICAL IMPLICATIONS: Although topical CB dental bleaching did not reduce the risk of TS and color change, these agents slightly reduced the TS intensity, but the certainty of the evidence is very low.

Influence of smoking on the effectiveness of tooth whitening: a systematic review.

OBJECTIVES: Perform a systematic review to evaluate the influence of smoking on the effectiveness of tooth whitening (TW) and to analyze whether tooth sensitivity is different between smokers and non-smokers. MATERIALS AND METHODS: A systematic review modeled according to the PRISMA guidelines was conducted. PubMed, Embase, Web of Science, Cochrane, Scopus, and OpenGrey databases were searched for related clinical trials. The population, exposure, comparison, outcomes (PECO) was individuals who had TW performed, smoking individuals, non-smoking individuals, and effectiveness of TW, respectively. Risk of bias was assessed with the ROBINS-I tool, and data from included studies were extracted by two researchers independently. The certainty of the evidence was evaluated using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) approach. RESULTS: Five studies were selected for qualitative analysis. The ROBINS-I tool classified 3 studies as having a moderate risk of bias, one study as having a serious risk of bias, and one with a critical risk. GRADE performed only for color change results and showed a low certainty of evidence. Limited evidence suggests that effectiveness of TW between smokers and non-smokers is similar. The tooth sensitivity also does not seem to be influenced by smoking. Due to the heterogeneity of the data, a meta-analysis could not be performed. CONCLUSIONS: Effectiveness of TW between smokers and non-smokers is comparable. The tooth sensitivity also does not seem to be influenced by smoking. CLINICAL RELEVANCE: The effectiveness of bleaching among smokers and non-smokers appears to be similar. Tooth sensitivity during TW also appears not to be influenced by smoking.

One-year clinical observation of the effect of internal bleaching on pulpless discolored teeth / 华西口腔医学杂志

OBJECTIVES@#This study aimed to observe the color rebound and rebound rates of non-pulp discolored teeth within 1 year after routine internal bleaching to guide clinical practice and prompt prognosis.@*METHODS@#In this work, the efficacy of bleaching was observed in 20 patients. The color of discolored teeth was measured by using a computerized colorimeter before bleaching; immediately after bleaching; and at the 1st, 3rd, 6th, 9th, and 12th months after bleaching. The L*, a*, and b* values of the color of cervical, mesial, and incisal parts of the teeth were obtained, and the color change amounts ΔE*, ΔL*, Δa*, and Δb* were calculated. The overall rebound rate (P*) and the color rebound velocity (V*) were also analyzed over time.@*RESULTS@#In 20 patients following treatment, the average ΔE* of tooth color change was 14.99. After bleaching, the neck and middle of the teeth ΔE* and ΔL* decreased in the 1st, 3rd, 6th, 9th, and 12th months, and the differences were statistically significant. Meanwhile, from the 9th month after bleaching, the rebound speed was lower than that in the 1st month, and the difference was statistically significant. The incisal end of the tooth ΔE* and ΔL* decreased in the 6th, 9th, and 12th months after bleaching, and the differences were statistically significant. No significant difference was found in the rebound speed between time points. However, this rate settled after the 9th month, with an average color rebound rate of 30.11% in 20 patients.@*CONCLUSIONS@#The results indicated that internal bleaching could cause a noticeable color change on pulpless teeth. The color rebound after bleaching was mainly caused by lightness (L*), which gradually decreased with time, and it was slightly related to a* and b*. The color of the teeth after internal bleaching rebounded to a certain extent with time, but the color rebound speed became stable from the 9th month. Clinically, secondary internal bleaching can be considered at this time according to whether the colors of the affected tooth and the adjacent tooth are coordinated and depending on the patient's needs.

Efficacy of products for bleaching and whitening under orthodontic brackets.

INTRODUCTION: Many patients wearing orthodontic appliances request alterations in the shade of their teeth during orthodontic treatment. OBJECTIVE: This study aimed to evaluate the efficacy of different products for bleaching and whitening under orthodontic brackets. METHODS: Seventy bovine incisors were randomly divided into five groups (n = 14): C) non-whitening toothpaste (control); WTsi) hydrated silica whitening toothpaste; WThp) 2% hydrogen peroxide whitening toothpaste; OB) in-office bleaching; and HB) at-home bleaching. Two buccal surface areas were evaluated using the Easyshade spectrophotometer: under the metal bracket (experimental) and around the bracket (control). The paired t-test, ANOVA, and Tukey tests were applied for statistical analysis. RESULTS: Intragroup comparisons showed that in groups C, WThp and HB, there were statistically significant differences in the enamel color changes (ΔEab) between under and around the bracket areas (C - under bracket = 7.97 ± 2.35, around bracket = 2.86 ± 0.81, p< 0.01; WThp - under bracket = 4.69 ± 2.98, around bracket = 2.05 ± 1.41, p< 0.01; HB - under bracket = 7.41 ± 2.89, around bracket: 9.86 ± 3.32, p= 0.02). Groups WTsi, OB and HB presented similar perception of tooth whiteness (ΔWID) between the tested areas. Intergroup comparisons demonstrated that under the bracket area, the color change (ΔEab) was similar for all groups, except WThp (C = 7.97 ± 2.35; WTsi = 8.54 ± 3.63; WThp = 4.69 ± 2.98; OB = 9.31 ± 4.32; HB = 7.41 ± 2.89; p< 0.01). CONCLUSIONS: The dental color changes were effective for the products tested in groups WTsi, OB and HB in the presence of metallic orthodontic brackets.

Effect of 1.5% potassium oxalate on sensitivity control, color change, and quality of life after at-home tooth whitening: A randomized, placebo-controlled clinical trial.

OBJECTIVE: This clinical trial evaluated the effect of 1.5% potassium oxalate (PO) in controlling sensitivity and color change after at-home tooth whitening. It also evaluated the influence of PO on health-related quality of life (HRQoL) and the degree of patient satisfaction after bleaching treatment. MATERIALS AND METHODS: Fifty volunteers were randomized into two groups (n = 25): At-home bleaching gel with 22% carbamide peroxide for 45 min + placebo gel (GP) or 1.5% PO (GPO) for 10 min. The intensity of tooth sensitivity was assessed daily through the visual analog scale. The color analysis was performed three times: baseline, 21 days, and 1 month after the last application of the whitening gel. The impact of the oral condition on the patient's quality of life (OIDP) was used to measure the impact caused by the whitening treatment in relation to the individuals' ability to carry out their daily activities and its influence on HRQOL. RESULTS: No difference in tooth sensitivity was observed (p > 0.05). In addition, there was no difference in color change between groups (p > 0.05). However, there was an intragroup statistical difference throughout the evaluation period (p <0.05). The OIDP analysis showed a statistical difference between the groups (p > 0.05) and there was no difference between the groups regarding the degree of satisfaction with the bleaching (p > 0.05). CONCLUSIONS: The 1.5% PO was effective in preventing sensitivity and did not interfere with tooth whitening. Desensitizing therapy had a positive impact on quality of life and patient satisfaction.

At-home Bleaching with a Novel Carbamide Peroxide Polymeric Nanoparticle Gel: A Multicenter Randomized Controlled Trial.

OBJECTIVES: To compare the risk and intensity of tooth sensitivity (TS) as well the effectiveness of at-home bleaching using two carbamide peroxide bleaching gels, specifically a novel polymeric nanoparticle gel (experimental) and a commercial gel (Opalescence PF, Ultradent, South Jordan, Utah, USA), applied at two application times. METHODS: This multicenter, triple-blind, and split-mouth randomized controlled trial was conducted on 80 healthy adults with canine teeth that were shade A2 or darker. The participants all used the experimental and the control gels on one side of a tray, depending on the group to which they were allocated, for 30 or 60 minutes per day over four weeks. The absolute risk and intensity of TS were assessed daily using the five-point Numeric Rating Scale and the 0-10 Visual Analogue Scale. Color change was evaluated with shade guide units (ΔSGU) and a digital spectrophotometer (ΔEab, ΔE00, and ΔWid) at baseline and 30 days postbleaching. The risk and intensity of TS was evaluated by the McNemar and the Wilcoxon signed-rank tests, respectively. Color change (ΔSGU, ΔEab, ΔE00, and ΔWid) was evaluated by Mann-Whitney and paired t-tests (α=0.05). RESULTS: No differences in the risk and intensity of TS were observed based on the bleaching gels used and the times of application (p>0.05). Thirty days after bleaching, there was no significant difference in color change, in terms of the bleaching gels used or the application times (p>0.05). CONCLUSION: The novel carbamide peroxide polymeric nanoparticles gel, when applied for 30 or 60 minutes, produced effective color change and a low rate of tooth sensitivity, as compared to the control group.