Written by Daniel H. Ward, DDS Sunday, 30 November 2003 19:00
|Figure 1. Pretreatment view.|
A single anterior incisor that has darkened following endodontic treatment can be a difficult problem to resolve. A conventional complete-coverage crown or ceramic veneer may not be deemed the most appropriate approach if there has been only minimal removal of tooth structure to gain proper access for endodontic root canal therapy. Matching a single crown with adjacent natural teeth can be a difficult task. Even if the resulting crown matches well upon seating, darkening of the natural teeth with age may cause the crown to become noticeable in the future.
|Figure 2. Agent placed in Calset composite warmer.|
One or a combination of these materials is placed into the pulp chamber and the access opening sealed. The patient returns, and the process is repeated for as many times as deemed appropriate. The in-office technique involves the placement of high-concentration peroxide on the outer surface of the tooth as well as inside the pulp chamber. Techniques incorporate the use of heat, heat lamps, curing lights, lasers, and special catalysts.2-6 The purpose of the various outside energy stimuli is to accelerate the process. Many of the devices can be quite cumbersome and may be perceived as intrusive by the patient.
|Figure 4. Lingual view of agent placed within pulp chamber.|
|Figure 5. Additional light activation of agent.|
Niveous (Shofu) is a tooth-whitening gel that contains 27% hydrogen peroxide in a sealed gel capsule. The gel-like material contains proprietary pigments and catalysts that respond to light and to a special applicator tip (Booster Brush) that is impregnated with an activator. This simple unit-dose system is convenient and safe. The capsule is placed in a heater that warms the gel to 130°F, making the gel more reactive and eliminating the need for auxiliary equipment. The heater used in the case report presented in this article is the Calset heater (AdDent Inc), which is designed to heat to 130°F and also can be used to warm composite resin, allowing a better handling material with enhanced polymerization conversion rates.7 The energized tooth whitener reacts with the stain on the teeth, giving improved and quicker results. Chair time and patient discomfort are significantly reduced.
A patient presented to the office after undergoing endodontic therapy on tooth No. 8 several years before. The tooth had subsequently darkened and was not aesthetically pleasing to the patient. He had received whitening treatments on several occasions. The results of these “walking bleach” technique treatments can be seen in Figure 1. He inquired about his options and was not interested in a complete coverage crown or a ceramic veneer since the access opening for endodontic root canal therapy was minimal. The patient was aware of several conservative methods of whitening the tooth. Traditional tray-assisted home-bleaching methods would lighten all the teeth, possibly making it even more difficult to match the darkened tooth to the lightened adjacent teeth. It was decided that the whitening procedure should be limited to the right central incisor. A new method of heating the hydrogen peroxide prior to placement on the tooth was presented and readily accepted by the patient.
Prior to beginning the tooth- whitening process, radiographs were taken to evaluate the integrity of the root canal filling and bone around the tooth to be treated. The root canal filling must be of a material that can be partially removed without disturbing the apical section. If a silver point had been placed, it must be removed and the tooth re-treated and obturated with a semisolid root canal filling material. The filling material should be removed internally approximately 4 to 5 mm apical to the corresponding location of the free gingival margin on the midfacial aspect of the tooth.
|Figure 6. Restored lingual view.|
The facial surface of the tooth was scrubbed with pumice and thoroughly washed and dried. The warm capsule of tooth-whitening material was removed from the heater, opened with scissors, and an appropriate amount dispensed into a dappen dish. This was quickly painted onto the buccal surface and the entire inside pulp chamber with the activating brush. The brush was then rubbed across the surface of the tooth until a foaming reaction was observed. This indicates that the peroxide has been activated. The remaining encapsulated material was returned to the heating unit. The solution was left on the tooth for 15 minutes (Figures 3 and 4). Additional heat energy was applied by placing a curing light near the surface of the tooth (Figure 5). Assistance must be provided to prevent any of the whitening solution from contacting the tissue during this interval. After the appropriate time, the solution was carefully washed off and the process repeated 2 more times.
|Figure 7. Post-treatment view.||Figure 8. Satisfied patient.|
Dentists and patients committed to conservative treatment of darkened endodontically treated teeth have desired a quick, easy, predictable method of lightening teeth without the use of elaborate activation systems. This innovative technique can be used in the pursuit of those desires. When carefully followed on select patients, this method can give excellent results.
- Pearson HH. Bleaching of the discolored pulpless tooth. J Am Dent Assoc. 1958:56;64-68.
- Hodosh M, Mirman M, Shklar G, et al. A new method of bleaching discolored teeth by the use of a solid state direct heating device. Dent Dig. 1970:76:344-346.
- Tavares M, Stultz J, Newman M, et al. Light augments tooth whitening with peroxide. J Am Dent Assoc. 2003:134:167-175.
- Smigel I. Laser tooth whitening. Dent Today. 1996:15:32-36.
- Nutting EB, Poe GS. Chemical bleaching of discolored endodontically treated teeth. Dent Clin North Am. November 1967:655-662.
- Clinical Research Associates. New generation in-office vital tooth bleaching, part 2. CRA Newsletter. 2003;27(3):1.
- Freedman, G. Thermally assisted flow and polymerization of composite resins. Contemp Esthet Restor Pract. 2003:7(2) -46.
- Bearham A. The consequences of internal tooth bleaching. Aust Endod J. 1999;25(3):136-139.
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