In-office Bleaching Protocols Research Articles

Evaluating color change and hydrogen peroxide penetration in human and bovine teeth through in-office bleaching procedures.

Assess color alteration and hydrogen peroxide (HP) penetration in human and bovine teeth using various in-office bleaching protocols with different application times. Thirty healthy human premolars and 30 healthy bovine incisors were divided into five groups and subjected to different bleaching protocols: 2 × 15 min, 1 × 30 min, 2 × 20 min, or 1 × 40 min, with a control group for each tooth type. All teeth were treated with 35% HP gel. Color alteration was measured using digital spectrophotometry before and 1 week after bleaching. HP concentration within the pulp was determined via UV-Vis spectrophotometry. Statistical analysis included one-way ANOVA, Tukey's, and Dunnett's tests (α = 0.05). All groups exhibited significant color alteration, with no statistically differences among them (p > 0.05). However, significant differences were observed when compared with their respective control groups (p < 0.05). HP penetration into the pulp was evident in all bleached teeth compared to the control groups (p < 0.05), with the 2 × 20 group showing the highest HP levels within the pulp cavity, irrespective of tooth type (p < 0.05). A simplified 1 × 30-min protocol can be recommended as it effectively maintains color alteration and HP penetration, irrespective of whether human or bovine teeth. This study suggests that an in-office dental bleaching protocol using a 1 × 30-min session is recommended, as it ensures both effective color change and no increase in the amount of HP penetration.

Effectiveness of changing the color of darker teeth is potentiated by association with violet LED light

BackgroundThe effectiveness of in-office bleaching protocols performed with violet LED light either combined with a bleaching agent containing 37% carbamide peroxide, or not, was determined by comparing teeth with different degrees of darkening. MethodologyEighty bovine incisors were separated into groups of “light” teeth (luminosity greater than or equal to B3) and “dark” teeth (less than or equal to A3.5) to receive the protocols: HP - 35% hydrogen peroxide (Whiteness HP), CP - 37% carbamide peroxide (Whiteness SuperEndo), LED - violet LED light (Bright Max Whitening), CPLED - CP associated with the LED. For color analysis the CIEL*a*b* e WID, ΔEab, ΔE00 e ΔWID parameters were used. Data were analyzed using Mann-Whitney, Kruskal-Wallis, Dunn, Friedman or Nemenyi tests (α = 5%). ResultsHP and CP resulted in similar color change values (ΔEab, ΔE00 e ΔWID) for light and dark teeth (p > 0.05). Dark teeth showed better bleaching effectiveness (ΔEab, ΔE00 e ΔWID) than light teeth when CPLED was used (p < 0.05). LED showed color change that were below the limits of acceptability and perceptibility for ΔWID. Conclusionlight teeth are effectively bleached with the use of HP or CP, whereas dark teeth respond better to treatment with the CPLED protocol. Violet LED used alone did not show a satisfactory result.

Bleaching Stained Arrested Caries Lesions: In vivo Clinical Study.

Objective Conservative approaches to esthetically treat stained arrested caries lesions (s-ACLs) have not been explored in clinical studies. This study aims to investigate the efficacy of in-office dental bleaching agent, as a conservative approach, to esthetically treat s-ACLs. Materials and Methods Twelve patients ( n = 46) presented with s-ACLs were treated with 40% hydrogen peroxide (in-office bleaching protocol; 20 minutes × 3). Color values were measured using a spectrophotometer (CIE L*a*b*), aided with digital photography to assess visual color change clinically. Measurements were taken for each specimen at baseline and immediately after bleaching. Statistical Analysis The color change calculated before and after bleaching for each dental substrate was analyzed using paired t -test (α = 0.05). Results The bleached s-ACLs had a significant increase in L * values ( p < 0.001), and a significant decrease in both a * ( p = 0.001) and b * ( p = 0.007) values, indicating lighter color improvement (bleaching efficacy). The baseline mean of L *, a *, and b * values were 61.5, 2, and 15.4, respectively, and after bleaching were 67.7, 1.4, and 13.3, respectively, with a mean increase in ∆ E of >7.9, which resulted in a visible clinical stain improvement as orange/light brown stains were removed completely, while gray/black stains improved to a lesser extent. Conclusion Significant color improvement was observed when the in-office bleaching protocol (40% hydrogen peroxide) was used in orange/brown s-ACLs. However, it showed lesser improvement in gray/black s-ACLs.

Effect of violet LED light on in-office bleaching protocols: a randomized controlled clinical trial.

ObjectiveThis study evaluated the clinical effect of violet LED light on in-office bleaching used alone or combined with 37% carbamide peroxide (CP) or 35% hydrogen peroxide (HP).MethodologyA total of 100 patients were divided into five groups (n=20): LED, LED/CP, CP, LED/HP and HP. Colorimetric evaluation was performed using a spectrophotometer (ΔE, ΔL, Δa, Δb) and a visual shade guide (ΔSGU). Calcium (Ca)/phosphorous (P) ratio was quantified in the enamel microbiopsies. Measurements were performed at baseline (T 0 ), after bleaching (T B ) and in the 14-day follow-up (T 14 ). At each bleaching session, a visual scale determined the absolute risk (AR) and intensity of tooth sensitivity (TS). Data were evaluated by one-way (ΔE, Δa, ΔL, Δb), two-way repeated measures ANOVA (Ca/P ratio), and Tukey post-hoc tests. ΔSGU and TS were evaluated by Kruskal-Wallis and Mann-Whitney, and AR by Chi-Squared tests (a=5%).ResultsLED produced the lowest ΔE (p<0.05), but LED/HP promoted greater ΔE, ΔSGU and Δb (T 14 ) than HP (p<0.05). No differences were observed in ΔE and ΔSGU for LED/CP and HP groups (p>0.05). ΔL and Δa were not influenced by LED activation. After bleaching, LED/CP exhibited greater Δb than CP (p>0.05), but no differences were found between these groups at T 14 (p>0.05). LED treatment promoted the lowest risk of TS (16%), while HP promoted the highest (94.4%) (p<0.05). No statistical differences of risk of TS were found for CP (44%), LED/CP (61%) and LED/HP (88%) groups (p>0.05). No differences were found in enamel Ca/P ratio among treatments, regardless of evaluation times.ConclusionsViolet LED alone produced the lowest bleaching effect, but enhanced HP bleaching results. Patients treated with LED/CP reached the same efficacy of HP, with reduced risk and intensity of tooth sensitivity and none of the bleaching protocols adversely affected enamel mineral content.

Dental bleaching efficacy and impact on demineralization susceptibility of simulated stained-remineralized caries lesions

ObjectivesTo evaluate the efficacy of different bleaching systems on artificially created stained-remineralized caries lesions; and to assess the susceptibility of the bleached lesions to further demineralization. MethodsHuman enamel specimens were sectioned, polished, demineralized, and randomly divided into six groups (n = 21) to create stained-remineralized lesions, either non-metallic (non-Met: G1, G2 and G3) or metallic (Met: G4, G5 and G6). G1 and G4 received no bleaching treatment, while G2 and G5 were treated with 15% carbamide peroxide (at-home bleaching protocol; 4 h/d×7), and G3 and G6 with 40% hydrogen peroxide (in-office bleaching protocol; 20min × 3). Susceptibility to further demineralization was tested after bleaching treatment. Lesion mineral loss and depth were measured by transversal microradiography, and color change by spectrophotometry. Outcomes were analyzed using ANOVA models followed by Fisher’s PLSD tests (α = 0.05). ResultsMetallic-stained lesions were significantly darker (all p < 0.001) and more resistant to bleaching (p < 0.005) than non-Met ones. For both stain types, the at-home bleaching protocol was more effective than the in-office (p < 0.005); however, it also increased the lesion susceptibility to demineralization (p < 0.05) [ΔΔZ mean ± SD ranging from 205 ± 73 to 313 ± 188 (at home) vs. 132 ± 45 to 206 ± 98 (in office); p < 0.05]. After bleaching, non-Met lesions were significantly more susceptible to demineralization (p < 0.05), with the ΔΔZ ranging from 206 ± 98 to 313 ± 188 compared to Met lesions ranging from 132 ± 45 to 205 ± 73. ConclusionsAt-home bleaching protocol presented greater bleaching efficacy compared to in-office bleaching protocol. After bleaching, metallic-stained lesions were more resistant to subsequent demineralization compared to non-metallic stained lesions. Clinical significanceBleaching stained-arrested caries lesions may improve aesthetics but also increase susceptibility to demineralization, depending on the type of stain involved and bleaching system used.

Influence of enamel/dentin thickness on the toxic and esthetic effects of experimental in-office bleaching protocols.

This paper aims to assess the whitening effectiveness and toxicity of tooth-bleaching protocols applied to enamel/dentin disks simulating mandibular incisors (ICs) and premolars (PMs). A 10% hydrogen peroxide (H2O2) gel was applied for 3×15, 1×15, or 1×5min to enamel/dentin disks simulating mandibular ICs and PMs, and the trans-enamel and trans-dentinal diffusion products were applied to human dental pulp cells (1h). Professional therapy (35% H2O2-3×15min) was used as positive control, and non-bleached samples were used as negative control. Cell viability and morphology, oxidative stress generation, and odontoblastic marker expression were assessed. The H2O2 diffusion and enamel color change (ΔE) were also analyzed. The 10% H2O2 gel induced significant cell viability reduction only when applied 3×15min, with the intensity of oxidative stress and down-regulation of odontoblastic markers being higher in the IC group. The other experimental bleaching protocols caused slight alterations regarding the cell parameters evaluated, with intensity being related to enamel/dentin thickness. These effects were also correlated with higher H2O2 diffusion in the IC group. ΔE values similar as positive control were found for the 10% 3×15 and 1×15 protocols on IC group, after 4 and 6 sessions. Application of a 10% H2O2 bleaching gel for 15 or 45min to thin dental substrate significantly minimizes cell toxicity in comparison with highly concentrated gels associated with similar esthetic outcomes by increasing the number of bleaching sessions. Bleaching gels with 10% H2O2 applied in small teeth for short periods may be an interesting alternative to obtain whitening effectiveness without causing toxicity to pulp cells, which may be able to reduce the tooth hypersensitivity claimed by patients.

Penetration Capacity, Color Alteration and Biological Response of Two In-office Bleaching Protocols.

Hydrogen peroxide (H2O2) penetrates into the dental hard tissues causing color alteration but also alterations in pulpal tissues. Hard-tissue penetration, color alteration and the pulp response alterations were evaluated for two in-office bleaching protocols with H2O2. For trans-enamel/dentin penetration and color alteration, discs of bovine teeth were attached to an artificial pulp chamber and bleached according to the groups: BLU (20% H2O2 - 1x50 min, Whiteness HP Blue); MAX (35% H2O2 - 3x15 min, Whiteness HP Maxx); Control (1x50 min, placebo). Trans-enamel/dentin penetration was quantified based on the reaction of H2O2 with leucocrystal violet and the color analyzed by CIELab System. Twenty Wistar rats were divided into two groups (BLU and MAX) and their maxillary right molars were treated according to the same protocols of the in vitro study; the maxillary left molars were used as controls. After 2 days, the animals were killed and their maxillae were examined by light microscopy. The inflammation of pulp tissue was scored according to the inflammatory infiltrate (1, absent; 2, mild; 3, moderate; 4, severe/necrosis). Data were analyzed by statistical tests (α=0.05). MAX showed higher trans-enamel/dentinal penetration of H2O2 (p<0.05). The color alteration was similar for both groups (p>0.05), and different when compared to Control group (p<0.05). MAX showed severe inflammation in the upper thirds of the coronal pulp, and BLU showed moderate inflammation (p<0.05). In-office bleaching protocols using lower concentrations of hydrogen peroxide should be preferred due to their reduced trans-enamel/dentinal penetration since they cause less pulp damage and provide same bleaching efficiency.

Changes in surface roughness of bleached enamel by using different remineralizing agents

Objectives The purpose of this study was to determine the effect of fluoride gel, Remin Pro, and GC tooth mousse plus in changing surface roughness of enamel after bleaching procedures. Materials and methods Dental enamel blocks measuring 2 × 3 × 4 mm were prepared from nonerupted human third molars. The 38% hydrogen peroxide in-office bleaching protocols were performed. The specimens were randomly divided into three groups (n = 10 samples per group) according to the remineralizing agent used: group 1: using fluoride gel, group 2: using Remin Pro, and group 3: using GC tooth mousse plus. Measurements of surface roughness were carried out using a contact stylus profilometer before bleaching, after bleaching, and after remineralization. Results Data were analyzed using analysis of variance and Tukey's test. There was a highly significant difference of enamel surface roughness measurements among initial, after bleaching, and final regarding the three tested groups (P Conclusion GC tooth mousse plus and Remin Pro are more effective in reducing enamel surface roughness after bleaching than fluoride product.

Color alteration, hydrogen peroxide diffusion, and cytotoxicity caused by in-office bleaching protocols.

This study evaluated the color alteration, cytotoxicity, and hydrogen peroxide (HP) diffusion associated with different in-office bleaching protocols. Bovine enamel/dentin disks were subjected to three bleaching sessions with 35 % HP (three 15-min applications), 35 % HP (one 45-min application), or 20 % HP (one 45-min application). The control group was not bleached. Before bleaching, the disks were adapted to artificial pulp chambers positioned in compartments containing 1 ml of acetate buffer or medium, so that the dentin remained in contact with these substances. Immediately after bleaching, the HP that diffused through the disks was stabilized by acetate buffer and was quantified (two-way repeated measures ANOVA/Fisher's protected least significant difference (PLSD) test; α = 5 %). Cells of mouse dental papilla cell-23 (MDPC-23) were incubated in this culture media for 1 h, followed by analysis of cellular metabolism (methyl tetrazolium assay) (one-way ANOVA/Tukey test; α = 5 %) and morphology (scanning electron microscopy). The specimen color alteration (ΔE) was analyzed by reflection spectrophotometry (two-way repeated measures ANOVA/Fisher's PLSD test; α = 5 %). All protocols showed equal effectiveness at the end of the treatment. HP diffusion was significantly higher in the groups bleached with 35 % HP. Reapplication of 35 % HP resulted in increased diffusion only in the first session; however, the decrease in cell metabolism was similar for all studied protocols. Despite greater peroxide diffusion in the groups treated with 35 % HP, all protocols showed the same effectiveness and were cytotoxic to MDPC-23 cells. Bleaching protocols using high HP concentrations should be avoided because they exert aggressive actions on odontoblast-like cells.

High-concentrated carbamide peroxide bleaching agents effects on enamel surface.

Concern has been expressed regarding the adverse effects of peroxide-containing tooth bleaching agents on enamel surface. This study examined enamel average surface roughness before (baseline) and after an in-office bleaching protocol and investigated the influence of high concentrations of carbamide peroxide gels on its surface staining and morphology. Flat enamel surfaces were submitted to 35 and 37% carbamide peroxide or to no bleaching treatment (n = 10) and evaluated with a profilometer. Eight specimens from each group were randomly selected and immersed in a 2% methylene blue solution. Afterwards, specimens were ground into powder and prepared for the spectrophotometric analysis. Two remained specimens of each group were examined using a scanning electron microscope. Data were subjected to analysis of variance and Tukey test (P > 0.05). Baseline roughness average was statistically similar for all groups, however, 35% carbamide peroxide produced the roughest enamel surfaces. Different concentrations of carbamide peroxide produced similar staining means and enamel surface morphological alterations.

In-Office Bleaching in Tetracycline Stained Teeth: A Case Study

The aim of the study was to evaluate the efficacy of In-office bleaching protocol in tetracycline stained teeth. Discolored dentition diagnosed as homogenous dark brown tetracycline stained teeth was treated with in office bleaching protocol. Desired bleaching has achieved after six sessions of In-office bleaching protocol and satisfactory whitening was apparent throughout the postoperative two-year observation period. DOI: 10.3329/bmj.v36i2.3613 Bangladesh Medical Journal 36(2) 2007 52-55