Walking Bleach Research Articles

Bleaching internal untuk merawat perubahan warna gigi insisivus sentralis kanan atas (Laporan Kasus)Internal bleaching as a treatment to color-changed of right upper centralis canine (case report)

Intracoronal bleeding in the tooth pulp due to trauma is one of the causes of tooth discoloration. Anterior toothdiscoloration often cause esthetic problem that affect individual perfomance. Internal bleaching is a non-vitalbleaching method performed after endodontic treatment using strong oxidator agent in pulp chamber. This casereport discusses about internal bleaching treatment with walking bleach technique on tooth 11 after endodontictreatment. Concentration of hidrogen perokxide 35% was applied for 3-7 days, this procedure was repeated untilthe tooth color was gained. The tooth color was accomplished in second visit. As conclusion is internal bleaching astreatment of tooth discoloration due to trauma can provide a good result with good endodontic treatment.

Management of tooth discoloration in non-vital endodontically treated tooth - A report of 6 year follow-up

Discoloration of teeth, especially the anteriors, can result in considerably cosmetic impairment in young children. It is the pediatric dentist’s responsibility to supervise those children who seek to undergo a whitening treatment to ensure the maximum cosmetic benefit within the boundaries of oral and systematic health. Among bleaching tech niques, the walking bleach technique with sodium perborate and distilled water stands out because of its superior esthetic results with no side effects. This paper presents a case of tooth discoloration in non-vital tooth which was successfully bleached using walking bleach method. After 6 year follow up the prognosis was good with no reversal of tooth discoloration and absence of external cervical resorption.

“The effect of intracoronal bleaching on dentin microhardness - An ex-vivo study”

Aim: To determine the effect of carbamide peroxide gel combined with or without 2% chlorhexidine gel and the effect of sodium perborate in combination with three different vehicles on dentin microhardness following walking bleach technique. Method: 30 extracted maxillary anteriors were collected and sectioned at 2mm below Cemento-Enamel Junction. Endodontic access cavities were prepared and pulp was completly extirpated. The crowns were randomly divided into six groups. A fresh portion of bleaching agent was appropriately combined with the designated vehicle and placed in the pulp chamber. After 7 days, bleaching agent was changed. The procedure was repeated for 3 weeks. Dentin microhardness was tested. Result: The results were statistically analysed and Sodium perborate when combined with hydrogen peroxide showed the lowest microhardness. Conclusion: Chlorhexidine can be considered during intra coronal bleaching as an antimicrobial vehicle without adversely affecting dentin microhardness.

Diferentes alternativas de clareamento para dentes escurecidos tratados endodonticamente

O clareamento de dentes escurecidos e tratados endodonticamente constitui-se em uma possibilidade de tratamento estético que oferece maior preservação da estrutura dental e baixo custo, especialmente quando comparado aos procedimentos invasivos, como a confecção de facetas ou coroas. O peróxido de hidrogênio, o peróxido de carbamida e o perborato de sódio podem ser utilizados na superfície externa e interna dos dentes ou aplicados no interior da câmara pulpar, seguido pelo selamento coronário e troca do material clareador, em períodos de tempo pré-estabelecidos – técnica conhecida como Walking bleach. A aplicação de calor, visando a acelerar a reação química do clareamento dental (técnica termo-catalítica) tem sido questionada pelo fato de se constituir em um possível fator de risco para o desenvolvimento de reabsorção radicular externa, principalmente quando existe histórico de trauma dentário ou defeitos no cemento radicular. Portanto, a indicação precisa do material a ser utilizado deve ter como base o conhecimento da eficiência dos diversos agentes e a segurança do tratamento por eles oferecida. Assim, o objetivo deste estudo é revisar a literatura, considerando as diferentes alternativas de clareamento para dentes tratados endodonticamente e escurecidos, abordando os agentes clareadores mais utilizados, as diferentes técnicas, vantagens e desvantagens, e possíveis efeitos colaterais advindos dessas técnicas.

Effectiveness of carbamide peroxide and sodium perborate in non-vital discolored teeth

Objective: To evaluate the efficacy of 16% carbamide peroxide gel (CP16%), tetrahydrate sodium perborate (SP) and mixture (CP16% + SP), in walking bleaching of non-vital discolored teeth. Materials and methods: Sixty single-rooted human premolars with intact crowns were used and initial color was assessed using Vita shade guide and standardized photos. The teeth were stained using rabbit fresh blood for 18 days and photos of discolored teeth and color evaluation were performed. The teeth were divided into 4 groups (n = 15), according to bleaching agent used: G1) CP16% gel; G2) CP16% gel + SP; G3) SP + distilled water; G4: control. The bleaching agents were replaced twice at 7-day intervals for 21 days. All teeth were evaluated by two endodontists at days 0, 7, 14 and 21 and the color changes were assessed using Vita shade guide and standardized photos. The results were analyzed by Kruskal-Wallis and Dunn's tests (p=0.05). Results: The experimental groups presented statistically similar bleaching results (p>0.05) at the end of 7, 14 and 21 days. These groups presented significantly higher bleaching efficacy than control group (G4) (p<0.05). The mixture CP16% + SP promoted return of original color in 100% of teeth at the end of 21 days. Conclusion: It was concluded that three bleaching agents were effective in bleaching of stained teeth with blood products, especially at the end of 21 days.

Bleaching a devital primary tooth using sodium perborate with walking bleach technique: A case report

Nowadays, both children and parents place a greater value on appearance and aesthetics than has previously been the case. Primary teeth with intrinsic discoloration may be treated by a number of methods, including facings and abrasion. However, dental bleaching may offer a safer alternative that can be completed with less chair time and without harming dental structures. This case report describes the treatment of a darkened primary tooth of a 4-year-old boy with sodium perborate using the walking bleach technique and its 1-year clinical and radiographical follow-up. During this 1-year follow-up period, no signs of any pathology were observed either clinically (sensitivity to percussion or palpation, fistulae, color change) or radiographically (external or internal root resorption, apical radiolucency). In this study, using sodium perborate with the walking bleach technique is found to be successful in whitening primary teeth and can be recommended as a safe alternative for the bleaching of devital primary teeth with intrinsic discoloration.

The combination of sodium perborate and water as intracoronal teeth bleaching agent

Background: The color change on post-endodontic treated teeth can be overcome by intracoronal tooth bleaching using walking bleach. Some agents used in walking bleach are combination of sodium peroxide and hydrogen peroxide, and combination of sodium perborate and water. Purpose: The objective of this review is to provide information and consideration of using safe and effective bleaching agents in the field of dentistry. Reviews: On one side, the use of sodium perborate and water combination does not cause the reduction of dentin hardness, enamel decay, and root resorbtion. On the other side, the use of sodium perborate and 30% hydrogen peroxide combination indicates that it takes longer time in yielding the proper color of teeth. Conclusion: The use of sodium perborate and water combination as bleaching agents is effective and safe.

Ex vivo antimicrobial activity of several bleaching agents used during the walking bleach technique

To investigate ex vivo the antimicrobial activity of a paste of sodium perborate associated with various vehicles comparing it with 37% carbamide peroxide and 35% hydrogen peroxide. The antimicrobial activity of these agents was evaluated against three microorganisms: Enterococcus faecalis, Streptococcus mutans and Candida albicans. One millilitre of each tested substance was placed on the bottom of wells of 24-well cell culture plates. Six wells were used for each time period and group. Two millilitres of the microbial suspension was ultrasonically mixed for 10 s with the bleaching pastes and placed in contact with them for 10, 30, 45 s; 1, 3, 5, 10, 20, 30 min; and 1 and 2 h. After each period of time, 1 mL from each well was transferred to tubes containing 2 mL of freshly prepared brain heart infusion agar + neutralizers. Agar plates were inoculated in appropriate gaseous conditions. Data were analysed statistically by the Kruskal-Wallis test with the level of significance set at P < 0.05. In all groups containing chlorhexidine (groups 3, 5 and 7), the antimicrobial activity of the bleaching paste was significantly increased when compared with groups with other kinds of vehicle (groups 1, 2, 4, 6 and 8). For all tested groups, the most resistant microorganism was E. faecalis. Chlorhexidine when used as a vehicle for sodium perborate enhanced its antimicrobial activity.

Ex vivo evaluation of the effectiveness of bleaching agents on the shade alteration of blood‐stained teeth

To evaluate ex vivo effectiveness of the three formulations of bleaching materials for intracoronal bleaching of root filled teeth using the walking bleach technique. Extracted premolar teeth were stained artificially with human blood. After biomechanical preparation, the root canals were filled and a 3-mm thick intermediate base of zinc phosphate cement was placed at the level of the cementoenamel junction. The teeth were divided into four groups (n = 12): C (control, without bleaching material), A1 (sodium perborate + distilled water), A2 (sodium perborate + 10% carbamide peroxide) and A3 (sodium perborate + 35% carbamide peroxide). The bleaching materials were changed at 7 and 14 days. Evaluation of shade was undertaken with aid of the VITA Easyshadetrade mark (DeltaE*ab) and was performed after tooth staining and at 7, 14 and 21 days after bleaching, based on the CIELAB system. Data were analysed by anova for repeated measurements, Tukey and Dunnett tests (alpha = 0.05). The Tukey test revealed that group A1 (10.58 +/- 4.83 DeltaE*ab) was statistically different from the others (A2, 19.57 +/- 4.72 DeltaE*ab and A3, 17.58 +/- 3.33 DeltaE*ab), which were not different from each other. At 7 days: A1 was significantly different from A2; at 14 and 21 days: A2 and A3 were significantly better than A1; the Dunnett test revealed that the control group was different from A1, A2 and A3 at all periods (P < 0.05). Sodium perborate associated with both 10% and 35% carbamide peroxide was more effective than when associated with distilled water.

Time-Course Diffusion of Hydrogen Peroxide Through Human Dentin: Clinical Significance for Young Tooth Internal Bleaching

The purpose of this study was to record the time-course diffusion of hydrogen peroxide through human dentin from a peroxide carbamide gel designed for the walking bleach technique in order to determine its optimal renewal time. It was considered that the optimal renewal rate corresponded to the time necessary to achieve 80% of the maximal diffusion because a much longer time does not involve further significant diffusion. Thirty-six freshly extracted human premolars were used for this study. Eighteen were extracted for orthodontic reasons on patients under 20 years old (young-teeth group). Eighteen were extracted for periodontal reasons on patients between 40 and 60 years old (old-teeth group). The teeth were endodontically treated, and a flat defect was created at the enamel-cementum junction. The teeth were suspended in vials containing water, and the access cavities were filled with 20 microL of 20% hydrogen peroxide gel. The amount of diffusing hydrogen peroxide was assessed at 1 hour, 24 hours, 48 hours, and 120 hours. The diffusive flux and the maximal diffusion were calculated as well as the optimal renewal time. Hydrogen peroxide diffusion through young teeth lasted 352 hours but lasted 291 hours through old teeth. Diffusive flux and maximal diffusion were higher through young teeth than through old teeth. The optimal renewal time for young teeth was 33 hours and for old teeth was 18 hours.

Efficacy of intracoronal bleaching techniques with different light activation sources

To evaluate ex vivo the efficacy of 35% hydrogen peroxide for intracoronal bleaching when activated by LEDs, halogen lamp or by the walking bleach technique. Forty extracted human maxillary central incisors had their crowns resected 1 mm below the amelo-cemental junction and were submitted to artificial staining in centrifuged rat haemolysed blood. A 2-mm thick glass ionomer cervical plug was placed inside the canal, at the level of the amelo-cemental junction. Samples were divided randomly into five groups: group I received 35% hydrogen peroxide gel activated by LEDs. Group II received 35% hydrogen peroxide gel activated by a halogen lamp-based light curing unit. Group III received 35% hydrogen peroxide gel followed by the walking bleach technique. Group IV was neither artificially stained nor bleached (positive control) and group V was stained, but not bleached (negative control). The shade of the teeth was assessed visually by three independent and calibrated evaluators, before and after bleaching. The results were analysed using Kruskal-Wallis one-way analysis of variance and Dunn's post-test. No statistical differences regarding sample shades were found amongst groups for the tested internal bleaching techniques (P > 0.05). Hydrogen peroxide for intracoronal bleaching when activated either by LEDs, halogen lamp or by the walking bleach technique presented similar efficacy.

The complete endodontic obturation of immature permanent central incisors with mineral trioxide aggregate and using obturated MTA as barrier for walking bleaching

The use of mineral trioxide aggregate (MTA) for both complete obturation and as a coronal barrier for non vital bleaching in immature maxillary central incisor is reported. A 18 year- old female reported with pain and discoloration of upper central incisors. Radiograph revealed immature maxillary central incisors. Single step apexification was done with MTA and root canal system eras obturated with MTA followed, by using this obturated MTA as a barrier for non vital bleaching. After 2 weeks esthetic management was done with direct composite. Follow up radiographs after 6months and one year revealed good bone healing and closure of the apex.

Evaluation of dentin permeability after light activated internal dental bleaching

The aim of this in vitro study was to assess quantitatively the dentin permeability of human teeth after intracoronal bleaching therapy with 35% hydrogen peroxide activated by LEDs, halogen lamp or using the walking bleach technique. Forty human maxillary central incisors had standard access cavities performed and the cervical thirds of the canals were prepared with Gates-Glidden drills up to a size 130. Roots were resected between the coronal and middle thirds and the apical portions were discarded. A glass ionomer, 2 mm thick cervical plug was placed inside the canal, at the cement-enamel junction level. Group I received 35% hydrogen peroxide gel activated by LEDs. Group II was submitted to 35% hydrogen peroxide gel activated by halogen lamp. Group III received 35% hydrogen peroxide gel and the walking bleach technique was followed. Group IV (control) received a dry cotton pellet inside the pulp chamber with temporary restoration. Dentinal permeability was quantified by copper ion penetration. Linear measurements were obtained by analysis of digital images under x 5 magnification. Mean values and SD for the experimental groups were: I, 7.1% (+/-3.2%); II, 8.4% (+/-3.0%); III, 9.1% (+/-3.0%); IV, 1.3% (+/-2.8%). One-way ANOVA was used to analyze the results. Results showed an increase of permeability values for groups I, II and III when compared to group IV (control); however, no statistical differences were found between the three tested bleaching techniques. It can be concluded that 35% hydrogen peroxide activated by LED, halogen lamp or used following the walking bleach technique produced similar increase in dentinal permeability.

The ability of thiourea to scavenge hydrogen peroxide and hydroxyl radicals during the intra‐coronal bleaching of bloodstained root‐filled teeth

Hydrogen peroxide, an agent used in the intra-coronal bleaching of root-filled teeth for over a century, has been shown to diffuse from the pulp chamber to the outer root surface. Furthermore, it has been demonstrated that destructive hydroxyl radicals, the by-products of the bleaching process, have been detected on the external root surface. The control of such diffusion may be of importance in minimizing the risk of invasive cervical resorption (ICR) which has been linked to intra-coronal bleaching of discoloured root-filled teeth using hydrogen peroxide. The aims of the present in vitro study are to quantify the diffusion of hydrogen peroxide and hydroxyl radicals to the outer root surface following intra-coronal bleaching, and to evaluate the ability of thiourea incorporated into the bleaching protocol to scavenge residual hydrogen peroxide and hydroxyl radicals. Thirty-five single rooted premolar teeth with intact cementum at the cemento-enamel junction were used in this project. Thirty teeth were stained with red blood cells and root-filled with gutta-percha and AH26. The five unstained teeth were root-filled and constituted a negative control (Group 1). The stained teeth were divided equally into the following experimental groups and subjected to various intra-coronal bleaching regimes: Group 2--'walking bleach' with 20 microl 30 per cent w/w hydrogen peroxide; Group 3--20 microl 30 per cent w/w hydrogen peroxide and thermocatalytically activated; Group 4--20 microl acidified thiourea; Group 5--20 microl acidified thiourea and 20 microl 30 per cent w/w hydrogen peroxide; Group 6--20 microl acidified thiourea and 20 microl one per cent sodium hypochlorite; Group 7--20 microl acidified thiourea, 20 microl one per cent sodium hypochlorite and 20 microl 30 per cent w/w hydrogen peroxide. The reaction products of the bleaching process were quantified at the outer root surface using high performance liquid chromatography and electrochemical detection (HPLC-ECD). Results showed that hydrogen peroxide used alone in Groups 2 and 3 was able to be detected at the outer root surface in 100 per cent of the samples, and that the presence of the hydroxyl radical generated in both groups was detected in equal amounts (P < 0.05). When thiourea was incorporated into the bleaching protocols in Groups 5-7, it was shown to scavenge both hydrogen peroxide and hydroxyl radicals to a significant degree (P < 0.05). Acidulated thiourea is an effective scavenger of residual hydrogen peroxide and hydroxyl radicals generated during the intra-coronal bleaching of bloodstained root-filled teeth.

In Vitro Assessment of a Gel Base Containing 2% Chlorhexidine as a Sodium Perborate’s Vehicle for Intracoronal Bleaching of Discolored Teeth

The purpose of this study was to assess a gel base containing 2% chlorhexidine (CHX) as a vehicle to be mixed with sodium perborate for intracoronal bleaching of discolored teeth, comparing its bleaching efficacy to sodium perborate mixed with other vehicles; 37% carbamide peroxide and 30% hydrogen peroxide. There were 110 fresh bovine incisors artificially stained using whole blood. The samples were divided into 11 groups and the intracoronal bleaching was performed using the “walking bleach technique”. The bleaching agents were replaced three times at 7-day intervals. Using digital photos and a shade guide created for bovine teeth, the samples were evaluated at day 0, 7, 14, 21, and 28. On evaluation day, the photos were examined by three endodontists giving scores from 1 to 5 based on the shade guide created. Data were analyzed statistically by Kruskall-Wallis test. After 28 days, all evaluated teeth received scores that were statistically similar. Groups that used sodium perborate and a liquid vehicle bleached faster than those that used a gel based vehicle. The CHX gel allowed dissociation for the bleaching agent. The 2% CHX gel exhibited a good potential for use as a vehicle for sodium perborate or as a complement for carbamide peroxide.

Endodontic problems

If modern clinical techniques were carefully followed, many common endodontic problems would never occur. Incorrectly designed access cavities may make root canals both difficult to identify and to instrument. Careful study of the pre-operative radiograph is essential. Various aids are available to remove fractured instruments and failed root fillings, but the problem must first be correctly diagnosed. As more patients seek cosmetic procedures, the practitioner should be familiar with the 'walking bleach' procedure, again after careful diagnosis of the cause of the discolouration. The practitioner should also be fully aware of the prognosis for this and other endodontic procedures.

Review of the current status of tooth whitening with the walking bleach technique.

Internal bleaching procedures such as the walking bleach technique can be used for whitening of discoloured root-filled teeth. The walking bleach technique is performed by application of a paste consisting of sodium perborate-(tetrahydrate) and distilled water (3% H2O2), respectively, in the pulp chamber. Following a critical review of the scientific literature, heating of the mixture is contra-indicated as the risk of external cervical resorption and the formation of chemical radicals is increased by application of heat. An intracoronal dressing using 30% H2O2 should not be used in order to reduce the risk of inducing cervical resorption. This review provides advice based on the current literature and discusses how the walking bleach technique can lead to successful whitening of non-vital root-filled teeth without the risks of side-effects.

The comparison of microleakage on intracoronal restoration after non-vital bleaching

The purpose of the present study were to evaluate microleakage of a fourth generation dentin-bonding agent following a walking bleaching treatment, to determine the effect of temporary postbleaching dressing with calcium hydroxide on microleakage and to investigate the effect of delayed intracoronal restoration on microleakage. The results of this study were as follows : 1. Bleached groups showed more microleakage than unbleached group 2. Immediately restored group following bleaching procedure showed the highest microleakage score. 3. One-week delayed restorations showed less microleakage but there were no statistically significant difference between group II and III. 4. Provisional dressing with calcium hydroxide had no influence on microleakage. It is necessary to know the time that has elapsed from the bleaching treatment to the restoration procedure to achieve optimal seal, as well as to reduce the risk of microleakage in adhesive restoration.

Bleaching effect of carbamide peroxide gel on discolored nonvital teeth

The bleaching of discolored nonvital teeth is conservative treatment that satisfy the cosmetic desire. The most common method for this treatment, walking bleaching, is using 30% hydrogen peroxide and sodium perborate. Many alternatives are suggested for preventing the external cervical root resorption that is the common complication of the nonvital teeth bleaching with 30% hydrogen peroxide The same extent of oxidation reactions as that resulted by the bleaching with the application of 30% hydrogen peroxide and sodium perborate can also be acquired more safely by materials that contain 10% carbamide peroxide, used primarily for the bleaching of vital teeth. Therefore, this study was performed to evaluate the efficacy of 10% and 15% carbamide peroxide bleaching gel in nonvatal teeth bleaching. The internal bleaching of intentionally discolored teeth was performed in vitro with 10% carbamide peroxide (Group 1), 15% carbamide peroxide (Group 2), mixture of distilled water and sodium perborate (Group 3), and mixture of 30% hydrogen peroxide and sodium perborate (Group 4). The bleaching materials were refreshed following 3, 6, 9 and 12 days. To evaluate the bleaching effect, the color change of the crowns was measured at 1, 2, 3, 4, 7 and 15 days of bleaching using the colorimeter. The results were as follows：1. L and E values were increased with time in all bleaching agents (p and E value among bleaching agents. 3. E value higher than 3 was shown after 3 days of bleaching with 10% carbamide peroxide gel, 1 day with 15% carbamide poroxide gel, 4 days with mixture sodium perborate and distilled water and 4 days with mixture sodium perborate and 30% hydrogen peroride, respectively. These results revealed that the use of 10% and 15% carbamide peroxide bleaching gel in non-vital teeth bleaching is as effective as mixture of distilled water and sodium perborate and mixture of 30% hydrogen peroxide and sodium perborate. Accordingly, carbamide peroxide could be used clinically to bleach discolored non-vital teeth.

The Walking Bleach Procedure: An In Vitro Study to Measure Microleakage of Five Temporary Sealing Agents

The purpose of this study was to compare the in vitro sealing capacity of five materials, each used as a temporary sealing agent for the walking bleach technique. All teeth received traditional biomechanical root canal instrumentation, after which the walking bleach agent was placed in the pulp chamber space. The occlusal access was sealed with one of five temporary materials: two hydraulic filling materials, a photoactivated resin composite, a zinc oxide-eugenol cement, and a zinc oxide phosphate cement with/without the placement of a piece of rubber sheet that was placed as a barrier to isolate filling material from the bleaching agent. All teeth were stored in a 1% solution of Alcian blue with thermal cycling stress. After 1 wk, they were sectioned longitudinally, and ranked by graded scores of 0 to 3, according to the degree of the dye penetration. Significantly less dye microleakage was observed in the two hydraulic materials than in the photoactivated resin. Both zinc oxide-eugenol and zinc phosphate cements showed a considerable amount of microleakage. There were no significant differences between the groups with and without a rubber sheet. Our data demonstrate that hydraulic filling materials provide the most favorable cavosurface seal when they are firmly packed into the cavity space to prevent microleakage.