• Restorative Dentistry and Endodontics
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• v.24 no.3
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• pp.453-464
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• 1999

The non-vital bleaching technique has been used widely as a very effective treatment method on discolored non-vital teeth. But periodontal tissue deterioration and cervical external root resorption have been reported because of the high toxicity of hydrogen peroxide in bleaching agents. So in previous studies, placement of base over the root canal obturation prior to bleaching has been suggested in order to prevent microleakage of bleaching agents, however, the effectiveness of base is still controversial. The purpose of this study was to evaluate the effects of base and root canal sealer on prevention of leakage of bleaching agents in non-vital bleaching. Fifty-two extracted sound teeth with single root were used. For root canal obturation, Tubuli seal$^{(R)}$(Kerr Co., USA) was used in 39 teeth and in others, AH-26$^{(R)}$(De Trey Dentsply, Inc., Switzerland) was used as a root canal sealer. 26 teeth among the teeth obturated with Tubuli seal$^{(R)}$ were divided into two groups, and Dentin cement$^{(R)}$(GC corp., Japan) and JRM$^{(R)}$(De Trey Dentsply, Inc. Germany) were used in each group as a intracanal base. In all teeth, non-vital bleaching using bleaching agent mixed with methylene blue dye was performed and all specimens were stored in $37^{\circ}C$ water bath for 72 hours. After sectioning longitudinally, the depth of dye leakage was measured with digital vernier calipers under the stereobinocular microscope using ${\times}40$ magnification. It can be concluded as follows: 1. The microleakage of bleaching agent was observed ill all groups regardless of type of the base and the sealer. 2. The microleakage in the groups using AH-26$^{(R)}$ as a sealer was significantly reduced (p<0.05). 3. In the groups with intracanal base, micro leakage was observed through almost the whole depth of the base and there was no significant difference between Dentin cement$^{(R)}$ and IRM$^{(R)}$ group(p>0.05). In conclusion, all the basing materials and the sealers in this study did not prevent the microleakage of bleaching agent. Therefore further studies and attempts to seal off the pulp chamber will be necessary.

• Restorative Dentistry and Endodontics
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• v.27 no.4
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• pp.441-447
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• 2002

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 $\Delta$E$^*$ values were increased with time in all bleaching agents (p<0.01). 2. There was no significant difference in L$^*$ and $\Delta$E$^*$ value among bleaching agents. 3. $\Delta$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.

• Korean Journal of Dental Materials
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• v.46 no.1
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• pp.1-10
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• 2019

There are several causes of tooth discoloration following root canal treatment. In this study, we evaluated the effects of sealers on tooth discoloration and internal bleaching. Twenty-four teeth were divided into 4 groups: control group, AH plus, Endosequece BC, and MTA fillapex group. Root canal filling was performed using each sealer conventionally and non-vital bleaching was performed with sodium perborate. The L, a, and b values were measured using Vita easyshade. Tooth discoloration after root canal treatment occurs irrespective of the type of sealers and may cause discoloration with only gutta-percha cone. The effect of non-vital bleaching following the use of calcium silicate-based sealers such as Endosequece BC and MTA fillapex was higher than that of AH plus. Therefore, it needs careful use of sealers in endodontics and calcium silicate-based sealers have advantages of bleaching in case of discolored tooth.

• Restorative Dentistry and Endodontics
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• v.28 no.1
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• pp.57-63
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• 2003

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.

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.584.2-584
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• 2001

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 micro leakage. Forty extracted non-carious incisors were selected and conventional root canal treatment was performed. The teeth were randomly divided into 4 groups of 10 specimens each.(omitted)

• Restorative Dentistry and Endodontics
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• v.44 no.4
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• pp.39.1-39.8
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• 2019

The present report presents a case of dens invaginatus (DI) in a patient with 4 maxillary incisors. A 24-year-old female complained of swelling of the maxillary left anterior region and discoloration of the maxillary left anterior tooth. The maxillary left lateral incisor (tooth #22) showed pulp necrosis and a chronic apical abscess, and a periapical X-ray demonstrated DI on bilateral maxillary central and lateral incisors. All teeth responded to a vitality test, except tooth #22. The anatomic form of tooth #22 was similar to that of tooth #12, and both teeth had lingual pits. In addition, panoramic and periapical X-rays demonstrated root canal calcification, such as pulp stones, in the maxillary canines, first and second premolars, and the mandibular incisors, canines, and first premolars bilaterally. The patient underwent root canal treatment of tooth #22 and non-vital tooth bleaching. After a temporary filling material was removed, the invaginated mass was removed using ultrasonic tips under an operating microscope. The working length was established, and the root canal was enlarged up to #50 apical size and obturated with gutta-percha and AH 26 sealer using the continuous wave of condensation technique. Finally, non-vital bleaching was performed, and the access cavity was filled with composite resin.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.1
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• pp.131-138
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• 2006

A mixture of metronidazole, ciprofloxacin and minocycline(3Mix) in distilled water or in a root canal sealer were used to disinfect the infected endodontic and periapical lesions. It has been well acknowledged in recent literature that minocycline, a semisynthetic tetracycline derivative, causes discolorations in adult teeth and various other collagenous tissues. In these cases, pulp treatments were finished successfully using a combination of antibiotics but severe discolorations of the teeth were observed. Discolored non-vital posterior tooth was treated using the prosthodontic procedure. And anterior tooth was successfully treated using the walking bleach technique. Bleaching was performed by temporarily placing a mixture of sodium perborate and distilled water into the pulp chamber. There were significant esthetic improvement.