External Bleaching Research Articles

Effect of bromelain enzyme on the microleakage of composite resin restorations after external tooth bleaching: An in vitro study.

Aims:The aim of this study is to evaluate in vitro the effect of application of bromelain enzyme on the microleakage of composite resin restorations after external tooth bleaching using spectrophotometric evaluation.Subjects and Methods:Buccal Class V cavities were prepared on the surface of fifty intact premolars, which were randomly divided into five groups. All cavities were filled with composite resin. Group I: Teeth were not bleached but restored (n = 10). External bleaching with 35% hydrogen peroxide was carried out for the rest of the specimensGroup II: Cavities were restored immediately after bleaching (n = 10)Group III: Cavities were restored after a delay of 3 weeks (n = 10)Group IV: Cavities were treated with sodium ascorbate after bleaching and then restored (n = 10)Group V: Cavities were treated with bromelain enzyme solution after bleaching and then restored (n = 10). Microleakage was assessed by the dye extraction method using a spectrophotometer. Statistical Analysis Used:The data were analyzed statistically by comparison of mean microleakage and post hoc test using SPSS 2.0 software.Results:Group I displayed the least amount of microleakage, whereas Group II showed the greatest amount of microleakage (P < 0.05). Groups III, IV, and V showed a significantly lower amount of microleakage compared to Group II (P < 0.05). There was no statistically significant difference between Groups IV and V.Conclusions:Microleakage increased significantly after external bleaching with 35% hydrogen peroxide, and decreased when the bleached teeth were treated with antioxidants. Ten percent bromelain enzyme was effective in decreasing microleakage; however, its efficacy was similar to 10% sodium ascorbate.

The Effects of Three Bleaching Agents on Tooth Discoloration Caused by Mineral Trioxide Aggregate.

Successful outcome of pulp capping treatment using mineral trioxide aggregate (MTA), often leads to tooth discoloration. This study aimed to compare the efficacy of external bleaching technique with three bleaching agents naming hydrogen peroxide, carbamide peroxide and sodium perborate for correction of tooth discoloration caused by MTA. This in vitro, experimental study used 36 tooth blocks prepared from 12 bovine central incisors. White ProRoot MTA was applied in cavities; drilled in blocks for 40 days to cause discoloration. Then, the blocks were assigned to three experimental groups (n=12). Following application of hydrogen peroxide, carbamide peroxide and sodium perborate, the color parameters were determined at baseline and at 1, 7 and 14 days, using a spectrophotometer. Data were analyzed using repeated measure ANOVA and Tukey's test. No significant difference was noted in color change (∆E) immediately after bleaching with hydrogen peroxide and carbamide peroxide (P>0.05). However, these two groups had significant differences in ∆E with the sodium perborate group (P=0.001). Hydrogen peroxide group showed significantly higher ∆E at 1 week compared with other groups (P=0.01). The three groups were significantly different in ∆E at 2 weeks after bleaching (P=0.001). Pairwise comparisons revealed no significant difference between sodium perborate and carbamide peroxide in ∆E but they both had a significant difference with hydrogen peroxide (P=0.01). The three bleaching agents bleached the discoloured teeth effectively. Hydrogen peroxide had the highest efficacy whilst sodium perborate and carbamide peroxide had lower but similar efficacy.

Effects of External Bleaching on Restorative Materials: A Review

Aim: The aim of this comprehensive review is to present an update about the effects of external bleaching on restorative materials. Objective: External bleaching procedures utilizing peroxide compounds, including Carbamide peroxide, hydrogen peroxide, sodium perforate and calcium peroxide, are being used in bleaching products to improve the appearance of tooth. The main objective is to summarise and discuss the available information concerning the effects of peroxide releasing bleaching agents on dental restorative materials and restorations. Background: Multiple studies have evaluated the effects of bleaching agents on restorative materials such as amalgam, Dental alloy, glass ionomer, Dental ceramic and composite resin restorations, which can lead to increased surface roughness, crack development, marginal breakdown, release of metallic ions, and decreases in tooth-to-restoration bond strength. Reason: External bleaching might have a serious impact on restorative materials; these findings relate to possible physical and chemical changes and its effects on restorative materials is the main idea of this review.

Colorimetric evaluation of white spot lesions following external bleaching with fluoridation: An in-vitro study.

ObjectiveThis study was performed to investigate the effects of external tooth bleaching with flouridation on the appearance of white spot lesions (WSLs) in vitro.MethodsIn total, 125 bracket-bonded bovine incisor enamel blocks with artificial WSLs were randomly divided into a control group and four treatment groups (home bleaching, home bleaching + fluoridation, in-office bleaching, and in-office bleaching + fluoridation). A spectroradiometer (SR) and digital images (DIs) were used to evaluate colorimetric parameters (Commission Internationale l'Eclairage L*a*b*) for all specimens. Color measurements were obtained before WSL formation (T1), after WSL formation (T2), and after completion of the external tooth bleaching treatment (T3).ResultsThe SR-based color change after bleaching was significantly greater in the treatment groups than in the control group (p < 0.05). SR-based lightness (L*) and red-green (a*) values were significantly higher at T2 than at T1 (p < 0.001), with no significant changes in yellow-blue (b*) values. At T3, SR-based L* values had increased while a* and b* values had decreased in the treatment groups (p < 0.001). The DI-based color difference between the sound enamel and WSL areas (ΔE*DI) increased significantly from T1 to T2 in all groups (p < 0.001) and significantly decreased from T2 to T3 in the treatment groups (p < 0.001). No significant differences in ΔE*DI at T3 were shown between the four treatment groups (p > 0.05).ConclusionsThe findings of this study suggested that external tooth bleaching with fluoridation can alleviate the conspicuity of WSLs.

Internal and external bleaching

Internal and external bleaching

An in Vitro Study to Evaluate the Effect of Two Antioxidants on Microleakage of Composite Resin Restoration after External Tooth Bleaching

An in Vitro Study to Evaluate the Effect of Two Antioxidants on Microleakage of Composite Resin Restoration after External Tooth Bleaching

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.

Effects of antioxidants on the microleakage of composite resin restorations after external tooth bleaching.

Objective:To compare the effects of three antioxidants (sodium ascorbate, sodium ascorbate combined with a surfactant, and catalase) on the microleakage of composite resin restorations after external tooth bleaching with 10% carbamide peroxide.Materials and Methods:Buccal cavities were prepared on the surface of 60 intact premolars, which were randomly divided into six groups. All cavities were filled with composite resin. In group 1, teeth were not bleached; in group 2, cavities were filled immediately after bleaching; in group 3, cavities were delay-filled for 3 weeks; in group 4, cavities were treated with sodium ascorbate after bleaching and then filled; in group 5, cavities were treated with sodium ascorbate combined with surfactant after bleaching and then filled; and in group 6, cavities were treated with catalase after bleaching and then filled. Microleakage of the restorations was measured from sections using a stereomicroscope.Results:Group 1 displayed the least amount of microleakage, while group 2 showed the greatest amount of microleakage (P < 0.05). Groups 3 and 4 were similar to group 2 (P > 0.05). However, groups 5 and 6 showed a significantly lower amount of microleakage compared to group 2 (P < 0.05).Conclusion:Microleakage increased significantly after external bleaching with 10% carbamide peroxide, and decreased when the bleached teeth were treated with sodium ascorbate combined with Tween® 80, or with catalase. Catalase was more effective in decreasing microleakage, while delayed filling or treatment with sodium ascorbate alone did not effectively decrease the microleakage.

Evaluation of human enamel permeability exposed to bleaching agents

AIM: To evaluate the human enamel permeability after different external bleaching techniques. METHODS: The coronal portions of 20 maxillary human incisors were covered with an acid resistant varnish, except the labial surface, to prevent dye penetration of silver nitrate. The specimens were divided randomly into four groups (n=5) according to the bleaching treatments: Group 1 (G1) - without bleaching agent (control group), Group 2 (G2) - 35% hydrogen peroxide (HP) - one session of three 10-min applications, Group 3 (G3) - 35% HP - 2 sessions of three 10-min applications, and Group 4 (G4) - 6% HP - 14 days (1h/day). G1 was exposed to artificial saliva only and in the other groups the bleaching agents were applied following the manufacturers' recommendations. After bleaching, teeth were immersed in a 50% silver nitrate solution for 2 h and photodeveloped for 16 h. Then, three longitudinal slices of each tooth were photographed by an optical microscope (100x). The degree of dye penetration was analyzed in the middle third of the dental crowns using a 0 to 4 score system (0= no dye penetration, 1= less than half the enamel thickness, 2= half of the enamel thickness, 3= full extent of enamel without reaching the dentin, and 4= tracer agent reaching dentin). The data were analyzed statistically by the Kruskal-Wallis and Dunn tests (α=0.05). RESULTS: The median (1st/3rd interquartiles) ranges were: G1: 0(0/0), G2: 2(2/3), G3: 3(3/3) and G4: 3(3/3). G2, G3 and G4 showed significantly higher dye penetration compared with G1 (p=0.0017). CONCLUSIONS: The use of bleaching agents increased dental enamel permeability, regardless of the bleaching technique.

Influence of microhybrid resin and etching times on bleached enamel for the bonding of ceramic brackets

The aim of this study was to evaluate the shear bond strength (SBS) of polycrystalline ceramic brackets (PCB) bonded after bleaching treatment using different composite resins and enamel etching times. A total of 144 bovine incisors were randomly divided into two study groups (n = 72, each) as follows: G1, enamel bleached with 35% hydrogen peroxide, and G2 (control group), enamel unbleached. After the bleaching treatment, the samples were stored in artificial saliva for 14 days. These groups were further divided into two subgroups (n = 36, each) as follows: GA, brackets bonded with Transbond XT (3M) and GB, brackets bonded with Filtek Z250 (3M). For each resin used, three different etching times with 37% phosphoric acid (15, 30 and 60 seconds) were tested. SBS tests were performed using a universal testing machine (EMIC), and the adhesive remnant index (ARI) score was verified. Significant differences among the three experimental conditions and interactions between the groups were observed. The type of composite resin accounted for 24% of the influence on the bond strength, whereas the etching time and bleaching treatment accounted for 14.5% and 10% of the influence on bond strength, respectively. The ARI revealed that the most common area of adhesion failure was at the composite resin-bracket interface. The type of composite resin, etching time and external bleaching significantly influenced the SBS of PCB on enamel, even after 14 days of saliva storage.

Effects of catalase, 2% chlorhexidine gel and 1% sodium hypochlorite on the microtensile bond strength of teeth bleached with 35% hydrogen peroxide

Introduction and objective: Dental bleaching is an effective, relatively simple and noninvasive technique. The aim of this study was to evaluate the effects of catalase, 2% chlorhexidine gel, and 1% sodium hypochlorite on the microtensile bond strength to enamel of bovine teeth submitted to internal and external bleaching with 35% hydrogen peroxide. Material and methods: Sixty bovine incisors were used. They had their debris removed, washed in tap water and stored frozen. The samples were divided into five experimental groups according to the treatment applied after bleaching (n = 12): 1 − control/no bleaching (C); 2 − catalase (CA); 3 − 2% chlorhexidine gel (CG); 4 − 1% sodium hypochlorite (SH); 5 − distilled water (DW). For microtensile test, samples were prepared into blocks of enamel/resin, which were sectioned to obtain hourglass-like specimens. Bond strength was calculated in MPa and data analyzed statistically by Anova (p &lt; 0.05).Results: Microtensile bond strength means decreased in comparison to control group, but no statistically significant difference between groups was found. Conclusion: The substances used after dental bleaching did not result in statistically significant microtensile bond strength means of the tested groups.

Clareamento Interno e Externo em Dentes Despolpados – Caso Clínico

Currently, the tooth bleaching became a procedure very looked and used in the clinic dental, in function of the aesthetic valuation. The decision of bleaching always comes of the aesthetic necessity of the patient. The objective in this work is to present a clinical case of internal and external bleaching of pulped teeth being approached the materials, the technique and the cares that we must take in the hour of the intervention, so that let us can get the desired success. The treatment consisted of the association of the perborato of sodium with distilled water (folder), also showing the cares that if must have at the moment of the procedure. The clinical results had allowed to conclude that the efficiency of the use of the water distilled in substitution to hydrogen peroxide if makes gift, beyond the refined criterion in the choice of the bleaching treatment.

Ex-vivo evaluation of the intrapulpal temperature variation and fracture strength in teeth subjected to different external bleaching protocols

This study evaluated the influence of bleaching protocols on intrapulpal temperature and fracture strength of the bleached teeth. Ninety maxillary incisors were assigned to 9 groups (n=10): G1: 35% carbamide peroxide (35% CP), G2: 38% hydrogen peroxide (38% HP), G3: halogen light, G4: LED-laser, G5: 35% CP + halogen light, G6: 38% HP + halogen light, G7: 35% CP + LED-laser, G8: 38% HP + LED-laser, and G9: no treatment (control). Pulp space was widened, a thermocouple was introduced through the apex up to the pulp chamber and the temperature was recorded (°C). The fracture strength (kN) was determined using an Instron machine. Data were analyzed by ANOVA and Tukey's test (p<0.05). The halogen light alone (1.10 ± 0.24) (G3) and associated with 38% HP (1.15 ± 0.30) (G6) produced the highest temperature increase, statistically different (p<0.05) from the other groups. G1 (0.15 ± 0.06) and G6 (0.19 ± 0.07) produced the lowest values, statistically different (p<0.05) from G5 (0.65 ± 0.49). The bleaching protocols increased the temperature, but no increment exceeded the critical value of 5.6°C. Neither 35% CP nor 38% HP or the light sources alone altered the fracture strength of the teeth.

Diffusion of peroxides through dentine in vitro with and without prior use of a desensitizing varnish

Different bleaching regimens are used in dentistry possibly penetrating the dentine and affecting the pulp. The aim of the present study was to investigate peroxide diffusion through dentine pre-treated with a desensitizing varnish (Vivasens®) in a standardized in vitro setup during application of different bleaching materials. The penetration was tested using 1.3-mm-thick bovine dentine slabs. The following bleaching materials were tested with and without prior application of the desensitizing varnish on the external side of the dentine slabs: Vivastyle, Whitestrips, Simply White, Opalescence (external bleaching), and sodium perborate (internal bleaching, only tested without varnish; n = 8 samples per subgroup). The penetration of peroxides was measured photometrically using 4-aminoantipyrin as a substrate, the penetration of peroxides was monitored over 240 min. All bleaching agents yielded a diffusion of peroxides through the dentine, the kinetics of penetration were approximately linear for all materials tested. The significantly highest diffusion of peroxides was observed with Opalescence, the lowest with sodium perborate. The adoption of the desensitizing varnish reduced the diffusion of peroxides significantly for all external bleaching materials. Peroxides penetrated the dentine during application of bleaching materials; the penetration of peroxides can be reduced by application of a desensitizing agent.

Effects of external bleaching agents on dental tissues and cement–enamel junction

Effects of external bleaching agents on dental tissues and cement–enamel junction

New developments in tooth whitening. The current status of external bleaching in orthodontics

This article provides a contemporary view of external tooth whitening procedures currently available, with particular reference to bleaching. The various techniques and products are described, with their advantages, disadvantages, mode of action and the current legal stand-point discussed. The results of a British Orthodontic Society survey of Specialist and Practitioner Groups regarding current usage patterns of tooth whitening products are presented.

The effect of bleaching, varying the shade or thickness of composite veneers on final colour: An in vitro study

Objective To investigate whether bleaching prior to placement of a composite veneer had an effect on the final shade of the restoration and whether this was affected by the thickness or shade of the veneer. Methods Twenty bovine teeth were collected, sectioned and divided into two groups. One group was the non-bleached control, while the other was the bleached group. A colour reading was recorded using a spectrophotometer. The bleached group then underwent external bleaching with 38% hydrogen peroxide and a colour reading was recorded. Each of these two groups were further sub-divided into four subgroups, on which composite veneers were placed. These subgroups were: 0.5 mm thick A1, 1 mm thick A1, 0.5 mm thick A4 and 1 mm thick A4 composite veneers. Colour readings were recorded after veneer placement. Statistical significance was assessed using analysis of variance. Results There was a difference between the colour produced for the same veneer properties, between the bleached and non-bleached groups. For a thin (0.5 mm) A4 veneer bleaching produced a statistically significant difference in the amount of colour change (Δ E) compared to veneering alone. For A1, non-bleached group there is a significant difference in the Δ E produced by altering the thickness of the veneer. Conclusion Within the limitations of this study, we can conclude that bleaching prior to placement of a thin A4 dark veneer produces a significant difference in colour change. If no bleaching is performed, altering the thickness of an A1 veneer produces a significant colour difference Δ E. However, if bleaching is carried out there is no significant difference.

A randomized CIE L*a*b* evaluation of external bleaching therapy effects on fluorotic enamel stains.

To evaluate the effect of external bleaching on the color and luminosity of fluorotic stains and adjacent, normally mineralized enamel areas by means of CIE L*a*b* colorimetry. Eighteen adolescents with mild to moderate fluorotic stains were randomly assigned to either bleaching group A (n = 9) or control group B. Eligibility criteria were fluorotic stained maxillary incisors or canines and the informed consent of the participants and their guardians. Using a colorimeter, CIE L*a*b* values of maxillary incisors and canines were assessed at baseline (T1) in the center of the fluorotic stained area (F1) and at adjacent, normally mineralized enamel areas (F2). Then, external bleaching with Illumine office (30% hydrogen peroxide, Dentsply DeTrey) was performed for 60 minutes, followed by color reassessment (T2). After 14 days (T3), a 2-week home bleaching period with a daily bleaching time of 1 hour with Illumine home (15% carbamide peroxide, Dentsply DeTrey) was conducted with subsequent color determination (T4). After completion of bleaching therapy, 96.0% of all fluorotic areas (F1) and 100% of normal enamel areas (F2) showed a significant change within group A, compared to 29.4% in control group B. Comparing the collective DeltaE (L*, a*, b*) of F1 and F2, 60.0% of all areas showed significant differences after completion of bleaching therapy, compared to 88.0% initially. Of group B sites, 82.4% showed color differences in the beginning (T1) and 88.2% at the end (T4). Whereas a single 1-hour session of in-office bleaching with 30% hydrogen peroxide does not significantly affect the color and luminosity of fluorotic teeth, a 14-day period of home bleaching leads to an assimilation of the color of the fluorotic stain with the color of surrounding enamel areas due to different responses of sound and fluorotic enamel to the bleaching regime.

External Bleaching Effect on the Color and Luminosity of Inactive White-Spot Lesions after Fixed Orthodontic Appliances

To evaluate the effect of external bleaching on the color and luminosity of inactive white-spot lesions (WSLs) present after fixed orthodontic appliance treatment as means for achieving color matching of the WSLs with adjacent tooth surfaces. Ten patients with inactive WSLs after therapy with fixed orthodontic appliances were selected. At baseline, the lightness of maxillary incisors and canines was assessed with a colorimeter. Color determinations were performed in the area of the initial lesions (F1) and at adjacent, sound enamel areas (F2). Then, anterior teeth were bleached once with a bleaching gel for 60 minutes. After a break of 14 days, in-office bleaching was followed by a 2-week home bleaching period with daily home bleaching for 1 hour. After this, color determinations were repeated. Additionally, patients were asked to fill out a questionnaire to provide information about their degree of contentment with the treatment. The lightness values of both the F1 and F2 regions were significantly higher after bleaching as compared with baseline. F2 L-values increased significantly more as compared with F1, indicating a better color matching of these two areas in comparison with baseline. All patients were satisfied with the outcome of the bleaching therapy. External bleaching is able to satisfactorily camouflage WSLs visible after therapy with fixed orthodontic appliances.

Clareamento externo para dentes com calcificação distrófica da polpa: relato de caso clínico

Este trabalho descreve o tratamento de dentes com calcificação distrófica da polpa, que envolve geralmente uma alteração na cor do dente. Tradicionalmente, esses dentes eram tratados de maneira invasiva com confecção de facetas ou coroas dentárias. O clareamento externo é uma alternativa de tratamento que possibilita uma solução estética, conservadora e biológica, especialmente nos casos em que há uma dificuldade de acesso ao sistema de canais radiculares. O presente caso clínico mostra uma paciente que apresentava alteração de cor no incisivo central superior esquerdo, decorrente de calcificação distrófica total da câmara pulpar e do canal radicular, em função de um trauma. O tratamento englobou trinta dias de clareamento caseiro supervisionado, a partir do uso de moldeira com o gel de peróxido de carbamida a 16% e mais duas sessões de clareamento de consultório com peróxido de hidrogênio a 35% para resolver a intensa saturação no colo do dente.