Written by Theodore P. Croll, DDS Tuesday, 30 September 2003 19:00
Well-rendered, resin-bonded, custom-fabricated porcelain veneers have proven to be invaluable for imperceptible restoration of certain cosmetically prominent teeth. The appearance and optical properties of properly baked and glazed ceramic material mimic that of natural enamel, and many patients have enhanced oral health and greatly improved smiles because their dentists and the technicians they rely on have mastered the porcelain veneer technique. It should be recognized, however, that many tooth color abnormalities do not require treatment involving facial masking using bonded restorative materials. Often, tooth coloration defects can be eliminated and residual tooth color lightened as desired.
Dental bleaching and enamel microabrasion are 2 treatment methods that not only preserve tooth structure and are considerably less expensive than bonded restorations but also have proved to offer reliable and long-lasting tooth color improvement. This article describes tooth color correction for a child, a teenager, and an adult. Porcelain veneer restorations had been suggested for the older patients and as a future consideration for the child. Brief clinical protocols for enamel microabrasion and carbamide peroxide custom-tray home bleaching in combination with enamel microabrasion are offered.
Enamel microabrasion is analogous to dermabrasion on skin surfaces.1,2 Using a compound containing a mild concentration of hydrochloric acid and a fine-grit silicon carbide abrasive in a water-soluble gel, the enamel is reduced microscopically with a low-speed/high-torque gear-reduction handpiece. If the offending intrinsic tooth stain (dysmineralization or decalcification) does not penetrate deeply into the enamel surface, it is eliminated with insignificant and unrecognizable loss of tooth structure.
Two enamel microabrasion compounds are available commercially: PREMA compound (Premier Dental Products) and Opalustre (Ultradent Products). The enamel microabrasion procedure can be summarized as follows:
Diagnosis. Suspected superficial enamel coloration defects will be eliminated with microabrasion. Examples are isolated brown and white dysmineralization spots such as the ones seen with fluorosis. Although much enamel discoloration is attributed to excess fluoride intake in the years of amelogenesis, many superficial stains cannot be specifically identified as fluorosis. Idiopathic white/brown enamel dysmineralization is oftentimes a logical and more rational diagnosis. Incipient decalcification lesions are also easily eliminated with microabrasion.
Documentation. It is always useful to record a preoperative photograph for future documentation of treatment results.
Isolation. Using either the rubber dam or rubber dam substitute (OpalDam, Ultradent Products), teeth to be treated are isolated. Enamel microabrasion compounds contain a mild concentration of hydrochloric acid that can damage soft tissues with extended contact. (It is estimated that the risk is equivalent to that of 30% to 40% phosphoric acid used in resin-bonding procedures.)
Application of compound. Using a gear-reduction handpiece for high-torque, low-rpm application, the microabrasion compound is applied intermittently (10 to 15 seconds). Progress of treatment is determined with periodic water rinses and visual assessment. No anesthetic is required. It is often helpful to “jump-start” enamel reduction by using a slow-speed tapered diamond bur. Such initial mechanical reduction has been shown to hasten the procedure.
Assessment. Progress of treatment is evaluated and once the offending stain is eliminated, tooth surfaces are rinsed with water spray and covered with a topical fluoride gel (eg, Prevident, Colgate Oral Pharmaceuticals). The rubber dam or rubber dam substitute is removed.
Postoperative and long-term considerations. Tooth surfaces that have undergone enamel microabrasion have been shown to develop a smooth, lustrous texture.3-6 Using the scanning electron microscope, Donly, Segura, and others have identified and studied an “enamel glaze” of compacted amorphous mineral that characteristically gives a glass-like finish after treated teeth are subjected to the demineralization/remineralization phenomenon that continually occurs in the mouth.3-6 Segura et al have shown that microabraded tooth surfaces not only are more resistant to accumulation of dental plaque but also are less susceptible to dissolution to acid challenge.5,6 Results of enamel microabrasion are permanent. Discolored enamel is eliminated—not masked or merely optically altered.
Carbamide Peroxide Patient-Applied Dental Bleaching
Dental bleaching using vacuum-formed custom trays and hydrogen peroxide bleaching systems outside the dental office has become extremely popular since first described nearly 15 years ago.7-9 The method works well and usually the only complication is transient tooth sensitivity in some patients. A home-bleaching protocol is described as follows:
Stone model and tray preparation. A dental stone cast is poured into a full-arch alginate impression. The model is trimmed to a horseshoe shape with a thin border. Small reservoirs for extra bleaching solution in the tray can be produced by placing “plumping” material on the labial surfaces of teeth on the stone cast. Some dentists use light-cured resin material for this purpose. Mortite (Mortite, Inc), available at hardware stores, is a window-sealing material that also can be used to create excess space within the bleaching tray. Although such excess space does provide for additional bleaching solution, some dentists prefer trays without such reservoirs. After spraying the cast with silicon separating solution, 0.060-inch (5-inch x 5-inch precut sheets) soft vinyl tray material is vacuum-formed in the same manner as one would form a protective sports mouthguard. The 0.060-inch tray material is used for young patients because they tend to wear through the 0.035-inch material. Facial tray contours are cut around the free gingival/dental margins using scissors, a heat knife (Premier Dental Products), or manicuring clippers.
Patient instructions. The clinician needs to decide what type of bleaching solution is to be used (carbamide peroxide or hydrogen peroxide) and what concentration. My experience is that the lower-concentration bleaching solutions work well and tend to cause less tooth sensitivity. The patient is instructed to place a small amount of bleaching gel into each tooth segment in the tray. The tray is then seated in the mouth and excess gel is wiped away as it oozes out of the tray margins. The patient is advised to bleach either overnight or for a 2- to 4-hour period. Child patients must be assisted and supervised during dental bleaching.
Tooth sensitivity. Some patients experience tooth sensitivity during custom-tray home bleaching. The exact cause is unknown and clinical research is needed to clarify this problem and find a solution. I believe that tooth sensitivity during dental bleaching is not related to inflammation but could be associated with fluid dynamics. Just as gas inflates a balloon by exerting pressure internally, perhaps the oxygen molecules, diffusing through enamel and dentin, exert analogous pressure on nerve endings in the odontoblasts. As the pressure dissipates over time, the sensitivity subsides. Gingival irritation could possibly result from excess oxygen taken up in the soft tissues, also pressurizing nerve endings. Patients whose gingiva is uncomfortable during bleaching are advised to decrease the amount of solution placed in the trays. If a patient
has tooth sensitivity, daily bleaching time can be decreased or the trays can be used every other day. In some cases, ingested over-the-counter analgesics can be used. Other patients get relief by placing 1.1% neutral sodium fluoride gel (Prevident, Colgate Oral Pharmaceuticals) in the bleaching trays for 10-minute intermittent topical applications. Ultradent Products makes Opalescence PF, a bleaching solution containing potassium nitrate, which decreases discomfort for some patients.
REPORTS OF 3 PATIENTS
|Figure 1a. A 17-year-old with idiopathic brown and white enamel dysmineralization.||Figure 1b. Slow-speed application of PREMA compound used for enamel microabrasion.|
|Figure 1c. Immediately after application of the microabrasion compound.||Figure 1d. Bleaching solution injected into custom tray.|
|Figure 1e. Patient inserts custom tray containing bleaching solution.||Figure 1f. Patient seen 3 months after completion of enamel microabrasion combined with 3 weeks of home bleaching.|
A 17-year-old male had idiopathic white and brown enamel dysmineralization (Figure 1a). Consideration had been made at another dental office for porcelain veneer restoration of the central incisors, lateral incisors, and canine teeth in the maxilla. Using PREMA compound, enamel microabrasion was completed for the 4 maxillary incisors (Figures 1b and 1c). The patient then applied carbamide peroxide bleaching solution using a custom tray every day for 3 weeks (Figures 1d, 1e, and 1f).
|Figure 2a. A 25-year-old woman with unsightly brown enamel dysmineralization stain.||Figure 2b. Enamel microabrasion completed in one visit, using Opalustre compound.|
|Figure 2c. Two months after microabrasion, the enamel gives a smooth, lustrous appearance with no brown stain.|
A 25-year-old woman was referred by a local oral surgeon who had recently extracted her third molars. The patient had brown enamel dysmineralization defects on the labial surfaces of the maxillary central incisors (Figure 2a). When the surgeon had questioned her about the “brown spots” on her front teeth, she responded that her dentist for years had been suggesting veneers for her 6 upper teeth to both rid her of the brown discoloration and to give the illusion of straighter teeth without orthodontic correction. She related that the minor dental crowding was of no concern to her, and even though she did not like the brown markings, she did not desire to have her enamel cut away. Using Opalustre microabrasion compound (Ultradent Products), the brown enamel dysmineralization stain was eliminated (Figures 2b and 2c). The patient declined the suggestion of home bleaching, saying, “I like the color of my teeth; I just didn’t like those brown spots.”
|Figure 3a. An 8-year-old girl with generalized idiopathic white and brown dysmineralization.||Figure 3b. Three months after enamel microabrasion using PREMA compound, followed by 5 weeks of home bleaching.|
An 8-year-old girl was referred by another dentist. She had white and brown idiopathic dysmineralization of the maxillary incisors (Figure 3a). The referring dentist had told her parents that when she became an older teenager or adult, porcelain veneer restorations could improve her appearance but perhaps microabrasion and bleaching would be useful presently. He was right. PREMA compound was used to microabrade the incisors, followed by a 5-week course of custom-tray home bleaching using 10% carbamide peroxide solution (Figure 3b).
Enamel microabrasion and dental bleaching using carbamide peroxide or hydrogen peroxide solutions in custom-formed trays have been assigned separate dental insurance codes (03960 for bleaching of discolored teeth; 09970 for enamel microabrasion). Third-party coverage for these procedures is generally not available. Enamel microabrasion results are permanent because the superficial enamel lesion is removed, not masked. Bleaching results vary and some darkening of tooth shade is common in most patients within 3 to 5 years. Child patients and their parents should be told that bleaching results are not permanent, but the process can be renewed easily as the years go by.
Combining enamel microabrasion with dental bleaching has been a useful method for many patients.10-15 After eliminating superficial discoloration stains and creating a smooth surface texture to residual enamel, the underlying tooth coloration is then lightened, giving a bright, radiant appearance. In cases such as those described in this article, enamel microabrasion and dental bleaching should be the first treatment considerations for tooth color improvement.
The author recommends the following JADA Supplement to dentists interested in “nonrestorative” correction of tooth color abnormalities: Heymann HO. Nonrestorative treatment of discolored teeth: reports from an International Symposium. J Am Dent Assoc. 1997;128.
1. Croll TP. Enamel microabrasion for removal of superficial dysmineralization and decalcification defects. J Am Dent Assoc. 1990;120:411-415.
2. Croll TP. Enamel Microabrasion. Chicago, Ill: Quintessence Pub Co; 1991.
3. Croll TP, Segura A, Donly KJ. Enamel microabrasion: new considerations in 1993. Pract Periodontics Aesthet Dent. 1993;5:19-29.
4. Donly KJ, O’Neill M, Croll TP. Enamel microabrasion: a microscopic evaluation of the “abrosion effect.” Quintessence Int. 1992;23:175-179.
5. Segura A, Donly KJ, Wefel JS. The effects of microabrasion on demineralization inhibition of enamel surfaces. Quintessence Int. 1997;28:463-466.
6. Segura A, Donly KJ, Wefel JS, et al. Effect of enamel microabrasion on bacterial colonization. Am J Dent. 1997;10:272-274.
7. Haywood VB, Heymann HO. Nightguard vital bleaching. Quintessence Int. 1989;20:173-176.
8. Haywood VB, Leonard RH, Nelson CF, et al. Effectiveness, side effects and long-term status of nightguard vital bleaching. J Am Dent Assoc. 1994;125:1219-1226.
9. Heymann HO, Haywood VB. Nightguard vital bleaching. In: Goldstein RE, Garber DA. Complete Dental Bleaching. 1st ed. Chicago, Ill: Quintessence Pub Co; 1995:71-100.
10. Cvitko E, Swift EJ Jr, Denehy GE. Improved esthetics with a combined bleaching technique: a case report. Quintessence Int. 1992;23:91-93.
11. Killian CM. Conservative color improvement for teeth with fluorosis-type stain [published correction appears in J Am Dent Assoc. 1993;124:16]. J Am Dent Assoc. 1993;124:72-74.
12. Croll TP. Tooth bleaching for children and teens: a protocol and examples. Quintessence Int. 1994;25:811-817.
13. Croll TP. Esthetic correction for teeth with fluorosis and fluorosis-like enamel dysmineralization. J Esthet Dent. 1998;10:21-29.
14. Sarrett DC. Tooth whitening today [published correction appears in J Am Dent Assoc. 2003;134:24]. J Am Dent Assoc. 2002;133:1535-1538.
15. Price RBT, Loney RW, Dolye MG, Moudling MB. An evaluation of a technicque to remove strains from teeth with microabration. JADA. 2003;134:1066-1071.
Disclosure: The author acknowledges financial interest in PREMA compound and Opalustre by virtue of assignment of United States patent rights and licensing agreements with Premier Dental Products and Ultradent Products.
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