Bleaching Technique Research Articles

Stoichiometries of HCN-KCNE2 Channel

HCN channels play crucial roles in regulating heart beats and neuronal firing. The KCNE2 auxiliary subunit acts as an important regulator of HCN channel function, with different effects on each HCN isoform. Here we explore the stoichiometries of HCN channel pore-forming subunits with the KCNE2 subunit using a single-molecule fluorescence photo bleaching technique. We also examine the implications that KCNE2 mutations linked to sudden death have on these protein-protein interactions.

Frequently Asked Questions about Vital Tooth Whitening.

Improving patients’ aesthetics is an important request in daily practice. Tooth whitening is a treatment option available for improving aesthetics. This paper will pose questions asked by our patients on bleaching techniques and outcomes and offer appropriate up-to-date answers. Clinical relevance: This paper addresses the most important questions raised by patients and colleagues concerning vital tooth whitening (VTW).

Comparison of laser and power bleaching techniques in tooth color change.

BackgroundLaser-assisted bleaching uses laser beam to accelerate release of free radicals within the bleaching gel to decrease time of whitening procedure. The aim of this study was to compare the efficacy of power bleaching using Opalescence Xtra Boost® and laser bleaching technique using LaserSmile gel and diode laser as an activator in their tooth whitening capacity.Material and MethodsStudent t test showed that the laser bleaching group significantly outperformed the power bleaching group in changing ∆E (p=0.977).ResultsSimilarly, while comparing the groups in changing ∆L, the laser bleaching group indicated significantly superior results (p=0.953). Statistical data from student t test while comparing the groups in changing the parameter of yellowness indicated that samples in laser bleaching group underwent a more significant reduction than power-bleached samples (p=0.85). Correspondingly, changes in whiteness were statistically tested through student t test, showing that laser bleaching technique increased whiteness of the samples significantly more than those treated by power bleaching (p=0.965). The digital color evaluation data was in accordance with spectrophotometry and showed that laser bleaching outperformed power bleaching technique. Both techniques were able to increase whiteness and decrease yellowness ratio of the samples. ΔE decrease for laser bleaching and power bleaching groups were 3.05 and 1.67, respectively. Tooth color change in laser bleaching group was 1.88 times more than that of power bleaching group (p<0.001).ConclusionsIt could be concluded that under the conditions of this study, both laser-assisted and power bleaching techniques were capable of altering tooth color change, but laser bleaching was deemed a more efficient technique in this regard. Key words:Laser, power bleaching, tooth color introduction.

Management of discolored endodontically treated tooth using sodium perborate

The aim of this report is to depict the successful management of a discolored central incisor subsequent to endodontic treatment and its follow-up for 1 year. Improper bleaching techniques can lead to cervical resorption and eventual loss of teeth. Management of the discolored endodontically treated tooth can be performed using sodium perborate (SP). A 22-year-old female who had undergone endodontic treatment of the central incisor reported with discolored maxillary central incisor tooth. The case was managed with “walking bleach technique” using SP and water. The case was followed up for 1 year and there was no relapse. Proper selection of bleaching agent and technique had resulted in the conservative and successful management of the case. Appropriate bleaching technique should be selected to manage discolored teeth.

Effect of two different tooth bleaching techniques on microhardness of giomer.

BackgroundTooth bleaching is a safe and conservative treatment modality to improve the esthetic appearance of discolored teeth. One of the problems with the use of bleaching agents is their possible effect on surface microhardness of resin-based materials. The present study was carried out to evaluate the effect of in-office and at-home bleaching on surface microhardness of giomer.Material and MethodsSeventy-five disk-shaped giomer samples (Beautifil II) were prepared and cured with a light-curing unit. The samples were randomly assigned to three groups (n=25). In group 1 (control), the samples were stored in distilled water for 14 days. The samples in groups 2 and 3 underwent a bleaching procedure with 15% carbamide peroxide (CP) (8 hours daily) and 45% CP (30 minutes daily), respectively, for 14 days. Finally, the microhardness of samples was measured with Vickers hardness tester using a 100-g force for 20 seconds. One-way ANOVA was used to compare the mean microhardness values among the study groups, followed by post hoc Tukey test for two-by-two comparison of the groups. Statistical significance was set at P<0.05.ResultsOne-way ANOVA showed significant differences in the mean microhardness values among the study groups (P<0.001). Based on the results of Tukey test, microhardness in the bleached groups was significantly less than that in the control group (P<0.0005). In addition, microhardness in the 45% CP group was significantly less than that in the 15% CP group (P<0.0005).ConclusionsUse of both bleaching agents during in-office and at-home bleaching techniques resulted in a decrease in surface microhardness of giomer. The unfavorable effect of in-office bleaching (45% CP) was greater than that of at-home bleaching (15% CP). Key words:Dental restorations, hardness, tooth bleaching.

Influence of Intracanal Irrigants on Coronal Fracture Resistance of Endodontically Treated and Bleached Teeth: An In vitro Study.

Background:Irrigation has a key role in the success of endodontic treatment. Intracanal irrigant solutions have adverse effects on the physical properties of dentin.Aim:The present study aimed to evaluate the effect of different irrigation protocols on coronal fracture resistance of endodontically treated teeth undergoing bleaching treatment.Design and Materials and Methods:Access cavities were prepared in 120 maxillary premolars which were divided into two groups (n = 60) – Group A: nonbleached, Group B: bleached (B). Each group was subdivided into five subgroups based on irrigation protocol (n = 12); G1: normal saline (NS), G2: 2.5% sodium hypochlorite (NaOCl), G3: 10% citric acid (CA), G4: 17% ethylene diamine tetra acetic acid, and G5: NaOCl plus CA. In Group B, the teeth were bleached using 38% hydrogen peroxide and 20% carbamide peroxide gels as in-office and at-home bleaching techniques for 3 weeks. All the teeth were restored with composite resin, thermocycled, and incubated for 24 h. The specimens underwent fracture resistance tests. Data were analyzed with ANOVA, Tukey honestly significant difference test, t-test, and Chi-squared test (α =0.05).Results:T-test showed significant differences between each two corresponding subgroups (P < 0.0001). In Group A, NS demonstrated significantly higher fracture resistance compared to others; however, minimum fracture resistance recorded in G2. In Group B, the maximum fracture resistance was recorded in G1, with the minimum being recorded in G5. Samples irrigated with NaOCl and NaOCl plus CA exhibited significantly lower fracture resistance compared to NS subgroup (P < 0.05).Conclusions:Within the limitations of this study, it can be concluded that the irrigation protocol used during endodontic treatment with/without bleaching can affect the coronal fracture resistance.

Clinical performance of a combined approach for the esthetic management of fluorosed teeth: Three-year results.

The long-term clinical performance of combined therapy including enamel microabrasion and vital bleaching is debatable due to the abrasion of outer enamel surface. The aim of this longitudinal cohort study was to evaluate the 3-year clinical performance of enamel microabrasion in combination with vital tooth bleaching for the esthetic management of fluorosed teeth. Fifteen patients with 176 fluorosed incisors and canines were included in this study. All the teeth were treated with enamel microabrasion (Opalustre, Ultradent), and at-home bleaching technique (10% Opalescence PF, Ultradent). Fluorosed teeth were evaluated at baseline, after microabrasion, after combined therapy, and at 3-year follow-up in terms of esthetic criteria (esthetic appearance, brown stains, and opaque white areas), side effects, and patient satisfaction using visual analog scales. The data were statistically analyzed (α = 0.05). Fluorosed teeth revealed significantly better esthetic appearance after microabrasion and combined therapy and at 3-year follow-up compared to those at baseline (P P Conclusions: The combined therapy was effective in the esthetic management of fluorosed teeth. However, a significant relapse was observed in the esthetic appearance and brown stains of these patients after 3 years, which also reduced patient satisfaction.

The effect of different in-office bleaching techniques and etching procedures on bond strength of orthodontic brackets

The aim of this study was to compare the effects of different in-office bleaching techniques and acid/laser etching on bond strength of orthodontic brackets. Ninety-six extracted human premolar teeth were used in the study. The teeth were randomly divided into four groups according to different in-office bleaching techniques (n = 24); Group I: Diode laser-assisted bleaching, Group II: Er:YAG laser-assisted bleaching, Group III: In-office bleaching with LED, Group IV: Unbleached (control). After the samples were kept in artificial saliva for 2 weeks, each group were randomly divided into 2 subgroups according to etching methods; a–acid etching; b–laser etching. For laser etching Er,Cr:YSGG laser was used at 1.5 W, 15 Hz with 140 μs pulse duration for 20 s. For acid etching, 37% phosphoric acid was used for 30 s. The shear bond strength testing was performed using Instron Testing Machine with a crosshead speed of 1mm/min. Adhesive Remnant Index (ARI) scores were also measured. Data was analyzed using two-way ANOVA, Bonferroni, Kruskal Wallis and Mann Whitney U tests (p < 0.05). No statistically significant differences were found between bleaching groups and control (p > 0.05). There were statistically significant differences between acid and laser etching within each group (p < 0.05). Acid etching caused significantly higher bond strength values (p < 0.05). While no statistically significant differences were observed between the ARI scores of bleaching and control groups (p > 0.05), acid etching caused statistically higher ARI scores than laser etching groups (p < 0.05). In conclusion in-office bleaching either with LED or laser before bracket bonding did not affect bond strength. Prior to bracket bonding, acid etching of enamel caused higher shear bond strength values than laser etching.

Evaluation of morphological and chemical alterations in enamel, dentin and cementum after internal bleaching technique using different bleaching agents

Objective: The aim of this study was to evaluate the morphological and chemical alterations in enamel, dentin and cementum after internal bleaching using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). Material and Methods: Seventy-two bovine incisor teeth were prepared, cut and bleached for 7 days as follows: HP: 35% hydrogen peroxide gel; HP+SP: 35% hydrogen peroxide gel + sodium perborate; CP: 37% carbamide peroxide gel; CP+SP: 37% carbamide peroxide gel + sodium perborate; SP: sodium perborate + water; and control: deionized water. The specimens were sectioned and prepared for morphological analysis under SEM and analysis of calcium, phosphorus, oxygen and carbon levels using EDS. Results: A significant reduction was found in the calcium levels in enamel after treatment with CP + SP and CP (p &lt; 0.05). Carbon (organic part) was hardly altered in enamel. A significant reduction in the calcium levels was found in dentin in Groups HP+SP, CP and CP+SP. Phosphorus levels increased after SP+H20 (p &lt; 0.05) and CP (p &lt; 0.05). Carbon levels showed little variation and the largest amount was found in Groups CP and CP+SP (p &lt; 0.05); in the other groups there was no alteration. A significant reduction in the calcium levels was found in the cementum in Group CP+SP (p &lt; 0.05). Conclusion: Alterations in the enamel, dentin and cementum compositions occurred after bleaching and these alterations showed to be less significant with sodium perborate and water.Keywords: Carbamide peroxide; Hydrogen peroxide; Scanning electron microscopy; Sodium perborate; Tooth bleaching.

Effect of Adhesive Restoration and Bleaching Technique on the Concentration of Hydrogen Peroxide In the Pulp Chamber.

This study aimed to quantify the concentration of hydrogen peroxide into the pulp chamber in the presence or absence of adhesive enamel restorations and to analyze the resin-dentin interface of bleached groups. Bovine incisors (120) were randomly divided into three groups according to enamel treatment (n=40 each): (1) enamel without restoration (control); (2) enamel cavities (3 mm diameter × 1.5 mm depth) restored with a silorane-based (SB) system; or (3) enamel cavities (3 mm diameter × 1.5 mm depth) restored with a dimethacrylate-based (DB) system. Restorations were thermocycled, and all groups were submitted to one application of 35% hydrogen peroxide (HP) agent for 45 minutes and subjected to four light activation methods (n=10 each): without light, light-emitting diode (LED), LED/diode laser, or halogen light. Acetate buffer solution was placed into the pulp chamber before bleaching, and this solution was collected to spectrophotometrically determine the concentration of HP that reached the pulp chamber after bleaching. Rhodamine B was added to the HP agent and applied on additional enamel samples of each group for 24 hours. Samples were sectioned mesiodistally, and the bleaching agent was traced using confocal microscopy. According to two-way analysis of variance and Tukey test (α=0.05), the HP concentration in the pulp chamber of the control group was significantly lower than that of the SB group (p<0.05), regardless of light activation. No differences were observed between DB and SB groups and between control and DB groups, except for the DB halogen light activated group, which exhibited higher HP intrapulpal concentration (p<0.05). Confocal microscopy exhibited HP diffusion through the interface of the SB and DB restored groups as well as enamel prisms in the control group. The SB restorative system increased the HP diffusion into the pulp chamber, but HP was able to diffuse even in the absence of enamel restorations.

Effect of Er,Cr:YSGG laser irradiation on bovine enamel surface during in-office tooth bleaching ex vivo.

The aim of this in vitro study was to evaluate the effect of using Er,Cr:YSGG laser during in-office tooth bleaching on bovine enamel surface to evaluate the safety of this therapy on tooth tissues. Thirty-six enamel specimens were prepared from bovine incisors and divided into three groups: Group 1 specimens (control) received no bleaching treatment; Group 2 received a conventional in-office bleaching treatment (40% H2O2); Group 3 received laser-assisted bleaching procedure (40% H2O2) utilizing an Er,Cr:YSGG laser. The specimens were stored for 10days after the bleaching treatment in artificial saliva. Vickers hardness was determined using a microhardness tester, and measurements for surface roughness were done using a VSI microscope. Three specimens for each experimental group were examined under SEM and mineral composition of the specimens was evaluated using EDS. Data were statistically analyzed using one-way ANOVA, Tukey's post hoc, Wilcoxon signed rank and Kruskal-Wallis tests (a=0.05). The Vickers hardness of the enamel was reduced after in-office bleaching procedures (p<0.05), and changes in surface morphology of the enamel were observed. However, the surface roughness of the enamel was not influenced (p>0.05), and no changes in mineral composition of the enamel were detected after in-office bleaching procedures (p>0.05). The laser-assisted bleaching treatment with Er,Cr:YSGG laser did not influence the enamel surface compared to the conventional bleaching technique. The safety of the use of Er,Cr:YSGG laser during in-office tooth bleaching regarding the surface properties of the enamel was confirmed under in vitro conditions.

Bleaching and enamel microabrasion in the smile esthetics: a case report

The color change of teeth is frequent in the dental office and has important role in smile harmony. Objective: To discuss through case report the dental bleaching technique associated with enamel microabrasion to remove localized white spots on the maxillary incisors and canines. Case report: Patient, female, aged 18 years, attended the Clinic of the University of Ribeirão Preto complaining about the negative aesthetics of her smile due to the presence of white spots on teeth #13, #12, #11, #21, #22 and #23. After detailed anamnesis and clinical examination, the spots were diagnosed as enamel demineralization caused by cariogenic challenge occurred during the use of orthodontic brackets. Dental bleaching technique with 38% hydrogen peroxide was applied followed by enamel microabrasion with 6.6% hydrochloric acid and silicon carbide paste. After absolute isolation, 1 mm thick paste was applied on enamel stain with the aid of resin composite polishing abrasive rubber. Each application was followed by copious washing and analysis of the stain removal with wet enamel surface. In total, six applications of 10 seconds each were used. Finally, enamel polishing was executed with felt discs and diamond paste, and topical application of fluoride. Conclusion: It was concluded that bleaching associated with enamel microabrasion technique is a safe, simple, and effective option for solving the esthetics of teeth with white spots.

A Survey among Palestinian Dentists Regarding Preferences Over Vital and Non-Vital Teeth Bleaching:A Cross-Sectional Study

Background: With bleaching treatments becoming very popular, assessment was conducted among Palestinian dentists to check their preferences. Objective: To evaluate the preferences of general dentists regarding vital and non-vital tooth bleaching therapies and to investigate whether the time of clinical practice influences these options. MaterialM At home therapies were the least preferred (19.3%). Hydrogen peroxide more than 22% was the preferred treatment of choice for vital bleaching therapy (57.9%), whereas the combination of sodium perborate with water or hydrogen peroxide (46.5%) was the preferred treatment of choice for non-vital bleaching. There was a significant association between the time since graduation and the preference for in-office bleaching (P = 0.01) and no significant association between the time since graduation and the material used. Conclusion: In-office bleaching was preferred over at-home therapies; HP >22% and sodium perborate with water or HP were chosen as first treatment options to manage discolored vital and non-vital teeth, respectively. The time in clinical practice had an effect only on the choice of vital bleaching technique.

A new ultrasound-assisted bleaching technique for impacting chlorophyll content of cold-pressed hempseed oil

Ultrasonic treatment was applied to reduce chlorophyll of cold-pressed hempseed oil in conjunction with various clays. Bleaching clays such as bentonite (activated/non-activated), sepiolite and clay from a canola oil refining industry (industrial clay) were used. Ultrasonic bleaching of hempseed oil for 20 min at 20, 40 and 60% power (expressed as ultrasound amplitude) with bleaching clays (40 g/kg) reduced chlorophyll in decreasing order of effectiveness from industrial clay > activated bentonite > sepiolite > non-activated bentonite together with an increase in ultrasound power to 40%. At 20% ultrasound power, chlorophyll reduction (%) was found to be 99.4% (industrial clay) > 97.8% (activated bentonite) > 82.7% (sepiolite) > 47.1% (non-activated bentonite). The reduction in total phenolic content was 27.3%, 33.4%, 27.9% and 34.7% when treated at 20% ultrasound power with 40 g/kg clay from canola industry, activated bentonite, non-activated bentonite and sepiolite, respectively. The corresponding reduction in the peroxide value for the oil samples, due to the adsorptive nature of the clay, followed the trend of industrial clay > sepiolite > non-activated bentonite. This process proved promising for impacting hempseed oil color through reduction of chlorophyll.

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

A systematic review and meta-analysis were performed to evaluate the risk and intensity of tooth sensitivity during in-office and at-home bleaching in adult patients. The efficacy of dental bleaching was also evaluated. A comprehensive search was performed in the MEDLINE via PubMed, Scopus, Web of Science, Latin American and Caribbean Health Sciences Literature database, Brazilian Library in Dentistry, Cochrane Library, and System for Information on Grey Literature in Europe without restrictions. The annual conference of the International Association for Dental Research abstracts (1990-2014) and unpublished and ongoing trials registry were also searched. Dissertations and theses were searched using the ProQuest Dissertations and Periódicos Capes Theses databases. Only randomized clinical trials that compared the prevalence or intensity of tooth sensitivity during in-office and at-home bleaching in adult patients were included and studies that evaluated the efficacy of these dental bleaching techniques, in terms of shade guide units (ΔSGU) and in terms of color difference measured with a spectrophotometer (ΔE*). After the removal of duplicates, 1139 articles were identified. After title and abstract screening, 29 studies remained. Fifteen studies were further excluded, whereas 12 studies remained for qualitative analyses and 8 for the meta-analysis of the primary and secondary outcomes. No significant difference in the risk/intensity of tooth sensitivity or in bleaching efficacy was observed in the present study. In an overall comparison of at-home and in-office bleaching, no differences were detected, either regarding risk/intensity of tooth sensitivity or the effectiveness of the bleaching treatment. This comparison, however, does not take into consideration variations in the protocols (daily usage time, number of bleaching sessions, and product concentration) of the bleaching techniques in the studies included.

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

The aim of this study was to evaluate the efficacy, color stability, risk, and intensity of tooth sensitivity (TS) of combined bleaching techniques performed with 20% or 35% hydrogen peroxide for an in-office protocol. Thirty patients were randomly divided into two groups and submitted to a single 45-minute in-office bleaching session with 35% hydrogen peroxide or 20% hydrogen peroxide. At-home bleaching was performed with 10% carbamide peroxide for two hours daily over the course of two weeks. The color was evaluated with the value-oriented shade guide Vita Classical at different periods up to 12 months after bleaching. Patients recorded the intensity of TS using a five-point verbal scale. Color change data were submitted to a two-way repeated-measures analysis of variance and Tukey test (α=0.05). The absolute risk and intensity of TS were compared with the Fisher exact test and Mann-Whitney test, respectively (α=0.05). On average, an effective and similar whitening of three units in shade guide was observed for both groups, which remained stable for 12 months. When both protocols were compared, the one with hydrogen peroxide 35% showed a higher risk (p=0.02) and intensity of TS (p=0.04). In regard to the TS intensity, no significant difference was observed up to 48 hours after in-office bleaching (p=0.09) and during the at-home bleaching phase of the study (p=0.71). The combined bleaching technique using at-home bleaching associated with in-office bleaching was effective and stable over the course of 12 months, regardless of the concentration of the hydrogen peroxide used for in-office bleaching. However, the protocol with 20% hydrogen peroxide produced lower risk and intensity of TS.

Evaluation of the Diode laser (810nm, 980 nm) on color change of teeth after external bleaching.

Subject and aim: The aim of this study was to evaluate the efficiency of diode laser-activated bleaching systems for color change of teeth. Materials & Methods: 40 premolars with intact enamel surfaces were selected for five external bleaching protocols (n=8). Two different wavelengths of diode laser (810 and 980 nm) with two different hydrogen peroxide concentrations (30% and 46%) were selected for laser bleaching. Group 1 received bleaching (Heydent- Germany) with a 810 nm diode laser; Group 2 received bleaching (Heydent- Germany) with a 980 nm diode laser; Group 3 received bleaching (laser white*20- Biolase) with a 810 nm diode laser; Group 4 received bleaching (laser white*20- Biolase) with a 980 nm diode laser, with an output power of 1.5 W, in continuous wave (cw) mode for each irradiation. Group 5 as control group received 40% hydrogen peroxide (Opalescence Boost, Ultradent-USA) with no light activation. The color of teeth was scored at baseline and 1 week after bleaching with spectrophotometer. Color change data on the CIEL*a*b* system were analyzed statistically by the one-way ANOVA and Tukey's HSD test. Results: All the bleaching techniques resulted in shade change. According to ΔE values, all techniques were effective to bleach the teeth (ΔE ≥ 3). Statistically significant differences were detected among bleaching protocols (p=0.06). Regarding shade change values expressed as ΔL*, Δa*, Δb*, ΔE*, laser bleached groups were no statistically different with each other (p>0.05). Conclusion: Bleaching with different wavelengths of diode laser resulted in the same results.

Resin Bonding of Self-Etch Adhesives to Bovine Dentin Bleached from Pulp Chamber.

This study evaluated the microtensile bond strength (μTBS) of 1-step self-etch adhesives (1-SEAs) and 2-step self-etch adhesives (2-SEAs) to pulp chamber dentin immediately after bleaching with 2 types of common bleaching techniques. Pulp chamber dentin of bovine teeth was bleached using 30% hydrogen peroxide (H2O2) solution with quartz-tungsten-halogen light-curing unit (Group 1) and 3.5% H2O2-containing titanium dioxide (TiO2) (Pyrenees®) activated with 405-nm violet diode laser for 15 min (Group 2). Unbleached specimens were placed in distilled water for 15 min and used as controls. After treatment, dentin was bonded with resin composite using 1-SEA or 2-SEA and stored in water at 37°C for 24 h. Each specimen was sectioned and trimmed to an hourglass-shape and μTBS was measured. Fractured specimens were examined under a scanning electron microscope to determine fracture modes. All specimens in Group 1 failed before proper bonding tests. In Group 2, the μTBS of 2-SEA was significantly greater (with no failed specimens) than 1-SEA (where 21 out of 36 failed). These results indicate that 2-SEA is a better adhesive system than 1-SEA on bleached dentin. Our results also demonstrated that application of H2O2 significantly decreases bond strength of resin to dentin; however, in the case of nonvital tooth bleaching, Pyrenees® is a better alternative to the conventional 30% H2O2 bleaching.

PRODUTOS CLAREADORES OVER THE COUNTER: UMA REVISÃO DE LITERATURA

In order to the great aesthetic appeal for white teeth today, whitening has become very popular and affordable on the market. In the current days, there are many whitening products available in pharmacies, groceries and convenience stores. These products are called “over the counter” or OTC products. They are sold as cosmetics with non-prescription. The objective of this study is to review the literature articles surveyed in BVS, Scielo , Medline databases following the Descritores em Ciências da Saúde ( DeCS ) with emphasis on recent bleaching techniques introduced to the market as well as its indications, contraindications, advantages and disadvantages. OTC products do not have commercial regulation which hinders the supervision of tooth whitening by a dentist. These contain different concentrations of hydrogen peroxide or carbamide which can bring consequences such as tooth sensitivity and gum when used without indication and supervision.

Predictive factors on the efficacy and risk/intensity of tooth sensitivity of dental bleaching: A multi regression and logistic analysis

ObjectivesThe aim of this study was to identify predictor factors associated with the whitening outcome and risk and intensity of bleaching-induced tooth sensitivity from pooled data of 11 clinical trials of dental bleaching performed by the same research group. MethodsThe individual patient data of several published and ongoing studies about dental bleaching was collected and retrospectively analyzed. At the patient-level, independent variables (bleaching techniques [at-home and in-office protocols], sex, age and baseline tooth color in shade guide unit [SGU]) as well as dependent variables (color change in shade guide units (ΔSGU), color change in the CIEL*a*b* system (ΔE), risk and intensity of TS in a visual analog scale) were collected. Multivariable linear regression and multivariable logistic regression models were carried out using backward elimination whenever the p-values were higher than 0.05. ResultsA significant relationship between baseline color and age on color change estimates was detected (p<0.001). Every increase of one SGU in the baseline color resulted in an increase of approximate 0.66 in the final ΔSGU and 2.48 for the ΔE. For every increase of one year in the participant’s age we observed a decrease of the whitening degree of 0.07 for the final ΔSGU and 0.69 for the ΔE. The bleaching technique was shown to be a significant predictor of ΔSGU (p<0.001) but not of ΔE. In regard to TS, baseline color and bleaching technique are significant predictors (p<0.001). The risk of TS for at-home bleaching was 51% (95% CI 41.4–60.6) and for the in-office 62.9% (95% CI 56.9–67.3). ConclusionsYounger patients with darker teeth reach a higher degree of whitening. Patient with darker teeth and submitted to at-home bleaching presents lower risk and intensity of TS. Clinical significanceThe baseline color of the teeth and the patient’s age is directly related to the effectiveness of dental bleaching and TS.