Bleaching Teeth: History, Chemicals, and Methods Used for Common Tooth Discolorations Toni S. Fusanaro, D.D.S."
This article re\$ews the histow of bleaching teeth to lighten tooth color. The last 2 years have seen a dramatic increase in new bleaching methods and bleaching chemicals. The following categorizes bleaching chemicals and methods in relation to their use in treating common tooth discolorations. Special attention is given to home bleaching methods.
History of Tooth Bleaching
Need for Bleaching
1877 - Chapple's first published dental report on tooth bleaching using oxalic acid.' 1884- Harwan uses hydrogen peroxide as a bleaching agent.2 1895 - Garretson uses chlorine to bleach nonvital teeth.3 1916- Walter Kaine bleaches fluorosed teeth using muriatic acid (18% HC1 acid).2 1918-Abbot uses 35% hydrogen peroxide accelerated by heat from a light source.' 1970 - Cohen is first to bleach tetracycline-stained teeth using 35% H,02 and a bleaching instrument.' 1984 - Zaragoza bleaches maxillary and mandibular arches simultaneously with 70% H,O, + heat.' 1989 - Haywood and Heymann describe home bleaching using carbamide p e r o ~ i d e . ~ 1989 - Croll introduces hydrochloric acid paste system for superficial enamel discoloration.6
Fluorosis stains have a tremendous psychological effect on the patient and can be as disfiguring as a cleft lip or a facial scar.' Tetracycline tooth discoloration causes great anguish for children in a society that places a high value on appearance.8The dental profession has an obligation to treat tooth discoloration in the most conservative manner possible. In many cases tooth bleaching is the method of choice based on conservation of tooth structure and its effectiveness in lightening tooth discoloration.
Bleaching Process Superfiial Enamel Stains Superficial enamel stains are amenable to discing, acid erosion, and various peroxide solutions and methods. Deep enamel defects are best treated restoratively. Enamel-Dentin Stains Enamel-dentin stains are amenable to bleaching based on hydrogen peroxide's ability to penetrate both enamel and dentin to somehow liberate, oxidize, or break down stain molecules. Hydrogen peroxide's ability to lighten tooth color is not fully understood. Reports of diffuse penetration of intact enamel and dentin include:
Safety During the 113years of reported tooth bleaching in the dental literature, there is not one report of tooth brittleness fracture orpulpal necrosis. Employingproper bleaching methods can be both safe to the patient and effectivein lightening tooth color. Goldstein and kens report that heat bleaching a combined 40,000 teeth over 20 plus years has yielded neither pulpally damaged or fractured teeth.6A
1. In 1950Wainwright and Lemoine found substances of small molecular size, such as carbon- 14 labeled urea, diffused from the enamel surface to the pulp in 2 hour^.^ 2. In 1951 Bartelstone placed radioactive iodine on the tip of a cat incisor and found tagged iodine in the dental pulp within a short time.Io 3. In 1987 Bowles and Ugwuneri exposed the labial enamel surfaces of extracted pulpectomized teeth to 1%, lo%, and 30% H20,.All percentages were found to enter the pulp space within 15minutes."
'Private practice, Pleasant Hill. California. Dr. Fasanaro is also affiliated with the Postgraduate Bonding Practicum at the University of Pacific School of Dentisby. San Francisco, California Address reprint requests to Tom S . Fasanaro. D.D.S.. 70 Doray Drive. Pleasant Hill. CA 94523 0 1992 Decker Periodicals Inc.
71
though color relapse is common. However, the difficulty to patient and dentist has reduced its use to an adjunct to home bleaching in my practice. I have not found heat bleaching nearly as effective as home bleaching and use it only for single teeth such as dark cuspids.
Chemical Throy I . Enamel a] Acid pastes: permanently dissolve superficial enamel surface. 2. Enamel/Dentin a] Hydrogen peroxide: 2H,O, 2H,O + 2H'and for brief periods forms the perhydroxyl free radical HO,. which is enormously reactive with great oxidative power. I The free radical may break up the large macromolecular stain into smaller stain molecules and by diffusion expel them to the surface. It is also thought to attach to the molecular stain in the inorganic structure as well as protein matrix. b) H,O, -* H,O + 0, -+
Home Bleaching In more than 2.5 years and with 100 patients undergoing treatment, I have found this to be an extremely promising technique. Two plus shade improvements for yellow color (aging)have been seen in about 50-100 hours of bleaching time. More difficult yellow-grey tetracycline has taken 3 months and approximately 350 hours and yielded good improvement. During this period we have encountered little difficulty concerninghard or soft tissue other than transient cold sensitivity and soft tissue imitation caused by the bleaching splint. I consider home bleaching to be clearly the method of choice for tooth lightening and a milestone in the history of esthetic dentistry.
1 H'
+ HO; perhydroxyl free radical capable
of oxidizing tooth discoloration c) Pre-etching tooth with 30% phosphoric acid does not enhance bleaching results.'*
Patient Profile
TOOTH BLEACHING C HEMICALS
This is perhaps the most important aspect ofbleach-
ing treatment. Under no circumstances do we get a
Enamel Discoloration
lW?o result: usually we produce an improvement. There are no guarantees, and this must be candidly related to patients before they consent to treatment. Poor candidates include perfectionists, those who want whiter than white teeth, thosewith teeth that have large pulps, those with sensitive teeth, those with leaking restorations, sensitive root surfaces, and extremely dark stains, as well as patients who are not prepared for the rigors ofbleachingtreatment. Baseline photographic records employing a shade tab pre- and postoperatively against the teeth to be bleached are essential to verify tooth lightening and for future reference (Fig. 1).
Hydrochloric acid pastes and various H,O, methods can permanently remove superficial enamel discolorations. Use hydrogen peroxide bleaching agents for overall enamel discolorations caused by fluorosis. Should discoloration be limited to specific areas, then acid pastes are a conservative alternative. In some cases, both methods are employed. Hydrochloric acid pastes can permanently remove superficial enamel brown spots, white enamel opacities, and multicolored tooth surface defect^.^,^^.'^ Concentric super white areas are the result of hypocalciflcation and may extend to the dentinal border. They are best treated with bonded composite restorations. The recently introduced Croll system, Prema, is a major step forward:
Overview (Personal Experience) Nonuital Bleaching Nonvital bleaching has yielded dramatic color improvement over the last 2 1 years: however, it is impossible to predict or match the color of surrounding teeth. Retreatment approximately every 2 years is often required due to color relapse.
1. Extremely effective for superficial white enamel opacities, ortho bracket demineralization, multicolor yellow to brown stains, and irregular surface texture. 2. Employs 1O:l reduction handpiece (1000 rpm) to keep stiff acid paste confined to reduce splatter as well as a hand applicator for specific areas. 3. Versus disc or burr enamel surface removalmethod. HCl acid paste limits surface loss and creates a uniform appearance and is preferred to simple tooth reduction. 4. Precautions: Tooth isolation is mandatory to avoid soft tissue bums. Enamel surface loss is approximately 0.2mm. Checkanterior teethincisally every 10 seconds to monitor enamel removal. Five to seven applications are maximum. 5. Should the acid-paste system be ineffectivefor deepcolor defects, restorative options can be considered. l5
Fluorosis Over the last 8 years yellow to brown stains have yielded predictable removal of discoloration using a mild HF acid (Stripit) and thick prophylaxis paste delivered with stiff polishing cups and brushes. The recent introduction of the Croll Bleaching System is a great step forward. Should overall tooth lightening be required, as is often the case, I prefer H,O, home bleaching and the acid paste system for any localized areas not bleached.
Vital Bleaching I have bleached vital teeth using 35%H,O, and heat for 8 plus years. In all cases I have found improvement, 72
History, Chemicals. Methods
Dentin Discoloration
b) This amounts to approximately 1 1940H,O,. I find little need for these adjunct products as home bleaching alone works very well.
Overall dentin discoloration is commonly seen in nonvital teeth, with tetracycline ingestion. and in tooth aging.
Home Bleaching Hydrogen Peroxide 1.5Oh H,O,-Peroxyl. This is sold over the counter and bleaches slowly. 6%H,O,-Natural White. Rinse teeth with acetic acid for 20 seconds: apply 6% H,O,with cotton swab to teeth 1-2 minutes. Advertised as needing only 3 minutes per day; no mouthguard used. 2°h/50h/10% H,O,-Brite Smile. This is an officemonitored, at-home bleaching system using a vacuumformed tray. The dentist adjusts 35% H,O, with a .05% neutral sodium fluoride gel: progressive 2-5-10% solutions are introduced to the patient if there are no problems to accelerate process. If sensitivity to 10% solution occurs, they go back to the 5.0% solution. Recommended for 3 hours per day in a mouthguard; results are seen in 2-6 weeks. It employsa mucoprotectant for tooth isolation.
Offie Bleaching Hydrogen Peroxide 25% H,O, + no heat (e.g., Denta-Lite Plus). 35% H,O, +heat. The classic method employs light as a heat source and requires a rubber dam for tooth isolation. It is laborious for both patient and dentist when bleaching maxillae or mandible. It generally requires multiple treatments for most discolorations. Used for over 60 years 3 5 O h HzO, + heated instrument works well for 1 to 4 teeth such as dark cuspids, and requires a rubber dam or paint-on material for tooth isolation. Two recent studies noted initial lightness after one heat bleaching treatment that had reversed almost entirely at 1 month. l6 Subsequent bleachings resulted in a modest lightening effect" (e.g., Superoxol and Bleaching Light and/or Instrument, Union Broach). 35% H,O, + no heat + silicone dioxide thickener. "his is a new method that does not employ rubber dam or heat. Rather, it isolates teeth and protects gingivae with vaseline or a paint-on acrylic. The heavy gel is applied chairside for 20 minutes for nonvital teeth and 30 minutes for vital teeth. Multiple treatments may be required (e.g., Starbrite - Paint On Gingival Protectant, Bleachmaster, Pro-Brite, Accel, Studio 35). Note: 60 minutes of 35% H,O,did not change the elemental composition of bovine enamel.l 8 However, bond strength to resin is diminished.Ig 35% H,O, + curing light is a new powder-liquid system that is chemically (8-10 min) and curing-light activated in 2-3 minutes. It employs tooth isolation and is ideal for single tooth application, spot bleaching, or tetracycline band lightening (e.g., Hi Lite). 70% q O , + heat (officebleaching - B.V. Bleaching Vital System).'
Carbamide Peroxide Synonyms are urea peroxide, urea hydrogen peroxide, perhydrolurea, hydrogen peroxide carbamide, percarbamide. Carbamide peroxide was used in World War I as an anti-inflammatory antiseptic and in World War I1 to treat trench mouth. It has been used by dentists since 1960 for an oral wound debridement. In the 1960s Klusrnier noted tooth lightening using Gly-Oxide to assist post-traumatic tissue healing.,O Clinical reports of tooth lightening during gingivitis treatment using carbamide peroxide stimulated its use for tooth lightening. The current method was also described by John Munro who started his research in 1985for a medicine to accelerate wound healing post periodontal scaling.21 In March, 1989, Haywood and Heymann published their first article on home bleaching.6BCarbamide peroxide is marketed over the counter as Gly-Oxide(Marion Laboratories) and Proxigel (Reed and Carnrick). It is classified as an oral antiseptic by the FDA Monograph of 1974 along with 1.5 and 3.0% H,0,.23 Marion Laboratories has reported one adverse reaction in 30 years of Gly-Oxide use.24 Content is generally 10% carbamide peroxide, 88% glycerin, stabilizers, thickeners, and flavoring^:^^ it may or may not contain carbopol. Chemistry: 10% carbamide peroxide breaks down to 6.4% urea + 3.6% H,O,. The urea further breaks down to carbon dioxide and ammonia. The H,O, breaks down to H,O + 0, and liberates the chemically reactive free radical H0,- perhydroxyl for short periods.
1. The system was developed by Vincent Zargoza, M.D., D.D.S. (Spain) and employs custom-fitted thermotrays (4045°C): both maxillae and mandible can be bleached simultaneously. The soft tissues are isolated by paint-on acrylic. 2. 1-10 sessions, light yellow to violet. 3. Chemicals a) Enamel preparation-30% orthophosphoric acid, organic solvent, and ether. b) Soft tissue isolation. Cyanoacrylate. c) Bleach-7Ph H,O,, surfactants, amoniac hydroxide, persulphates, H,O. 4. Ten years of research were done in Spain, showing remarkable tooth lightening. I t was recently introduced in the U.S. as the BV-BleachingVitdSystem. 5. It may ultimately be the method of choice for greyblue tetracycline discoloration.
Urea Peroxide CH,N,O*H,O,
Carbamide Perodde a) 35% + no heat. Used as a start-up to home bleachingwith carbamideperoxide (e.g., Quick Start).
1
5
NH,
HzO,
+
CO,
73
5
H++HO;
1. Decided lightening in all cases without exception. 2. Most pronounced effect in the first 2 weeks, con-
1. The low molecular weight of peroxide allows it to
trayel freely through enamel and dentin.14 Staining may be due to disturbances in both organic and inorganic tooth formation. The oxygen-free radicals attach to the inorganic [stain)material on the teeth. The osidation of the organic (protein] double bond in theenamel, and outerlayers ofdentin, may break stain into smaller molecules. Stains are described a s macromolecular aliphatic chains located in interprismatic spaces and cracks. Oxygen bubbling enhances physical removal of the 2. Some home bleaching products employ carbopol (carboxypolmethylene pol-mer] to thicken carbamide peroxide to improve tooth adherence. It slows oxygen release 2.5 times longer than non-carbopolcontaining solutions (Proxigel patent). Both solutions work equally well.23Fluoride may also slow the bleaching process.L6 3. 10% carbamide peroxide yields 3.6%H,O,, while 15% carbamide peroxide yields 5.4% H,O,. 4. The life Of (Curs brochure) is 2-3 months. Always keep bleach refrigerated.
tinuing over a 3-month period. 3. Little if any change after 3 months. 4. Severe discoloration resists treatment. 5. Long-tem are unknown. Method A clear .020 (.5mm) vacuum-formed plastic splint
mouth-guard is constructed and trimmed a t or above the cementoenameljunction (CEJ).Die spacer increases comfort and may accelerate tooth lightening, but reduces retention. Change the bleaching solution hourly or with Carbopol every 3 or 4 hours: remove for meals and at night. Maximum treatment time is approximately 6 weeks or 300 hours. Recall weekly and monitor soft tissue and tooth structure; discontinue if any discomfort. Preserve casts for duration of treatment.23 Patient is instructed to keep a detailed diary of hours used, amount of bleach used in mL, and any complications encountered. This information is used for dental records, result evaluation, and future reference (Fig. 1). Postoperative Complications The majority of postoperative complications are related to tight-fitting splints and soft tissue abrasion upon splint removal. Sore areas include gingivae,tongue, and lips2’Swallowing of bleach may yield a sore throat or laxative effect due to glycerin content.23Other effects include cold or sweets sensitivity, discomfort due to sore teeth occluding on mouthguard. In the presence of soft-tissue inflammation, the gingivae may become ulcerated (deepithelialized).One report showed dissolution of composite resin matrix at 36 hours (White & brite, Proxigel).26The patient is instructed to discontinue if any side effects or difficulties occur.23 The appliance may require adjustment, or treatment should be stopped for 1-2 days until symptoms resolve. If no further problems are encountered, bleaching treatment is restarted. Contraindications include severe stain, severe enamel hypoplasia, pregnant or lactating women, hypersensitive teeth, known allergy to peroxide or glycerin, or lack of patient compliance to bleaching protocol.
Preliminary data indicate carbamide peroxide is nonmutagenic. LD 5.0-6.5 liters of Proxigel and 8 liters of Gly-O~ide.,~ Reviewing 20 articles covering 45 years, one author studying carbamide peroxide’s use as an oral antiseptic found it safe. An orthodontic study examining carbamide peroxide’s effect on caries over 3 years and approximately 1500 hours found no side effects.,’*A 1986study by Weitzman using 30% H,O, in the cheek pouch of hamsters over 22weeks found mild dysplasia in 50% of the a n i m a l ~ . ~ ~ L o n g - t etissue rm biocompatibility is not known at this time. Carbamide peroxide does not affect enamel surface texture, and no etching was apparent.22However, one study showed home bleaching reduced bond of composite to etched enamel. Removing surface enamel restored bond strength ~ o m p l e t e l yThere . ~ ~ is no noticeable effect on porcelain, resin, amalgam, or gold,30nor any incidence of permanent pulpal damage.23Bleaching appears to move laterally and lighten overall tooth color of teeth previously veneered with composite or porcelain, although the color of composite or porcelain does not lighten.22Therehas been stabilization of tooth lightening over 2 years,21although teeth do not always bleach evenly. The degree of lightening is directly related to the length of time the oxidizing agent is in contact with the teeth.31 Carbamide peroxide works very well on mild yellow, brown. or orange stains due to aging, fluorosis, tetracycline ingestion, and smokers’ stain. Extremely dark blue-grey stains will resist the bleaching process. The CRA Newsletter states that Dentlbright, Gly-Oxide,and Peroxyl bleach teeth more slowly than other products.26 In a 6-month study on home bleaching 6-8 hours per day by Ron J ~ r d a n ~ ~ * w40 i t hpatients at the University of Manitoba in Winnipeg, the following results occurred:
Available Products Carbamide peroxide products include the following:
a) 10% Carbamide Peroxide No Carbopol-Gly-Oxide, Denta Lite,White & Bright With Carbopol-Proxigel, Rembrandt Lighten, Dentlbright, Opalescence, Ultra-White, Smile Light, Ultra Lite Presaturated tray-Vital White b) 11% Carbamide Peroxide Enamelble~h~systemSmile~t,ADHBleaching Gel I c) 15%Carbamide Peroxide N u Smile
74
History, Chemicals. Methods
d)
16%Carbamide Peroxide ADH Bleaching Gel 11
1975 - Chandra and Chawla use 35% H,O, + 18% HCI + 5.25% sodium hypochlorite with fine cuttle discs. Stains were entirely removed with no reports of sensitivity.; 1984 - McClosky uses 18% hydrochloric acid + pumice +water to form a paste and applied with prophy cup. Also employs a cotton-tipped instrument in a light erasing motion, followed by a HCl paste on a prophy cup. He reported permanent stain removal."' 1989 - Croll introduces a 10% HCl paste system.n 1990 - US.400 areas in 28 states report enamel fluor~sis.~~
Over-the-counter (OTC)bleaching agents are quite unpredictable and potentially dangerous. I personally find bleaching toothpastes to be unnecessary and soft tissue response an unknown. A recent report of a 13year-old using an OTC bleaching product resulted in severe enamel erosion of the lingual surface of his maxillary anterior teeth. The product contained citric acid (CDA Journal, Sept.. 1991). Conclusion Home bleaching is the simplest bleaching method for significant lightening of enamel and dentinal discoloration: 2 + shade lightening in 4 to 5 days in many cases. Tooth structure lightens behind restorative veneers. There is much less discomfort than traditional 35% H,O, and heat. The long-term effects on soft tissue, color relapse, effect on restorative material and cements are not known at this time.
EuaIuation of Bleaching Method Stains are limited to outer enamel, precluding the necessity of hydrogen peroxide unless overall tooth lightening is required. The disc method of stain removal tends to remove excessive enamel. Therefore, acid abrasion pastes at slow speed orwith hand instrumentation yield a conservative method for permanent discolorized stain removal. Simple Stain - Intermittent white spotting or irregular brown stains. Prognosis: good Stains withRtting- Dark stain with surface deposits. Prognosis: dark stain responds well; severe pitting requires composite bonding. OpaquelOpalescent - Flat grey or white specks. Prognosis: difficult. Consider H,O, bleaching.
TYPES OF TOOTH DISCOLORATION Enamel Discolorations:Fluorosis Ingestion of > 1ppm fluorideduring the third month of pregnancy through the eighth year of life may result in enamel hypoplasia and staining. Ameloblasts are susceptible to > 1 ppm fluoride: 4 ppm yields severe discoloration. Fluoride is thought to affect improper calcification and a defective matrix f o r m a t i ~ nThis .~~ results in a well-mineralized enamel surface and a porous enamel Fluoride stains are limited to the outer one third of er~amel.~A common source of mild fluorosis today is from children swallowing fluoridated tooth paste while brushing, in addition to ingestion offluoridated water, rinses. or supplements (JADA, Vol. 122, Sept. 1991).
Precautions HCl leaves a dull surface that remineralizes in about 90 days. Transient cold sensitivity is normal (may require 1 4treatments.) Silky white patches are deeply ~ e a t e d deep : ~ hypoplastic defects require restorative treatment. Neutralize acid spills with sodium bicarbonate:37stimulate surface remineralization with a fluoride home rinse. Tooth isolation is mandatory.
Dentin: Tetracycline Stain
History of Fluorosis 1888- Kuhns describes black flecks in the enamel of the teeth of a family from Durango, 1901 - J. M.Eager notes enamel defects and black teeth among inhabitants near Naples.% 1901 - Fredrick McKay investigates tooth staining in Colorado Springs.35 1916- McKay and Greene Vardiman Black publish clinical findings of "mottling."36 1916 -Walter Kaine bleaches fluorosed teeth with muriatic acid (18% hydrochloric acid), alcohol, and a heated bleaching in~trument.~' 1931 - Churchill scientifically W s fluoride in water in Bauxite, Arkansas, to enamel discolorations. 1937 - Ames uses 5 parts 100% H,O, + 1 part anesthetic ether with a heated instrument. 1942 - Younger uses 5 parts 30% H,O, + 1 part anesthetic ether + heated in~trument.~' 1965- Bouschor on brown stains uses 5 parts 30% H,O, to 5 parts HC1 acid + 1 part anesthetic ether.39 1966 - McInness repeats Bouschor technique.32
Ingestion of tetracycline from the fourth month of pregnancy through the seventh year of life. The teeth forming at this critical period are the anterior teeth and are primarily limited to dentin matrix, which is also forming at the time., Fluorescent particles of tetracycline are thought to chelate to calcium in the mineralizing dentin at the hydroxyapatite surface40and are embedded in the collagen fibrils, which become the matrix for dentin Tetracyclines remain in dentin but rapidly disappear from Each dose taken yields a separate and individual stain.43The total mass of tetracycline is unlikely to exceed a few micrograms (BeMett. 1966).In 1963,yellow stain was linked to tetracycline a n d grey-brown to chlortetracycline.8Prolonged exposure to sunlight increases disc~loration.~~ Diagnosis: Positivefluorescence by Woods UV light.43
History of Tetracycline Bleaching 1948 - Tetracycline antibiotics are produced by soil organisms and used to combat cystic fibrosis, penicillinresistant organisms, and chronic bronchitkM 75
History
1956- Schwarhman reports tooth stain with tetra-
1895 - Garretson used chlorine to bleach nonvital teeth.55 1967 - Nutting and Poe introduce "walking bleach," 30% H,O, + perborate.g"
cycline 1 96 1 -Zegarelli confirms tetracycline stain in cystic fibrosis pa tien ts.*" 1963 - FDA adlrised physicians to use caution in
prescribing tetracycline during years of tooth formation.*' 1970 - Cohen and Parkins first attempt at bleaching tetracycline stains on cystic fibrosis patients.' 1977 - Falkensten uses 30% H,O, + 10% HCI acid one minute pre-etch + 100watt light bulb ( 1 04 deg F).47 1979 - Compton uses 3 5 O / 0 H20, + Indiana University bleaching instrument (130-145" F).4* 1985 - Abou-Rass combines endodontic therapy with internal bleaching emplo-ying 30% H,O, and 4-5 treatments &?thina 2-week period that yielded excellent esthetic results.lhAnother study showed a t 4years that only 6 of 258 teeth had slight color change ( r e l a p ~ e ) . " ~ 1990 - Combination. It is possible today to use heated 3 5 O h H,O,, unheated 35% H,O,. carbamide peroxide home bleaching separately or in combination. Evaluation of Bleaching Method Hydrogen peroxide is the bleaching agent of choice. The H,O, molecule penetrates enamel and dentin to liberate or alter the tetracycline molecule.50A short bleaching time, a carefully monitored heat source, if used, minimizes potential pulp damage.51I prefer home bleaching in most cases because of patient comfort and superlor results. Jordan and Boksman Tetracycline Stain Classi$cation5'*- Employing the 35% H,O, + Heat (Light)52
Evaluation of Bleaching Method It is very difficult to match existing tooth color: many treatments may be required. 1. Conservative lingual access. 2. Remove gutta percha below the cementoenamel
junction CEJ . 3. Place insoluble glass ionomer plug a t CEJ or above the surrounding bone height. Note: Diffusion of H,O, laterally below C E J has been linked to external res~rption.~' 4. 30% H,O, + perborate are placed in pulp space and sealed, changed weekly and repeated as necessary to lighten tooth color (e.g., 1-4 treatments). Note: After placing pellet, wait 5 to 10 minutes for hydrogen gas bubbling to end before placing temporary fill. 5. Etching coronal pulp and heated instruments are optional. 6. Seal lingual access with glass ionomer restorative. Lingual restoration should not employ etching and composite bonding as removal for futureretreatment is extremely difficult. 7. Repeat approximately every 2 years or as needed. Precautions Note: Postendodontic medicaments, sealing pastes, ZnO left in coronal pulp can yield discoloration. Lingual amalgam restorations to close endodontic access can create a silver oxide stain that is not bleachable.
I - Uniform light yellow, brown, or grey conflned to incisal3/4. Prognosis: good - 3 or less treatments: I1 -deep yellow, brown, or grey no banding. Prognosis: fair - 3 to 6 treatments: 111 - Dark grey or blue with marked banding. Prognosis:resists bleaching.53Up to 10treatments; and W - Severe stainsnot bleachable. Prognosis: PFM or endodontic therapy plus walking bleach.
Aging Discoloration As secondary dentin progressively obliterates the pulp space, tooth color progressively darkens (18 years old - A2: 40 years old - A3; 60 years old - A4 +). Historically, teeth have received 35% H,O, + heat, PFM, or porcelain veneer restorations. To treat discoloration from aging, I prefer home bleaching. The method is not difficult, and the results are dramatic for yellow, yellow-red, or brown discoloration.
Precautions Careful patient evaluation, well-sealed restorations, nonsensitive teeth, and total tooth isolation are primary considerations.
Hemorrhagic Discoloration
REFERENCES
Pulp necrosis creates blood breakdown products. If the cause of pulp necrosis is not caused by trauma but rather caries, there is a progressive protein degradation, which yields a greyish-brown discoloration.*Traumatic pulp death is thought to drive red blood cells into dentinal tubules hydraulically. The red blood cells undergo hemolysis producing a yellow-brown discoloration as the iron degrades to iron sulphide." Pinkorange-yellow-brown-blue or black - the severlty of discoloration is in proportion to the time between pulpal death and treatment.
1. Zaragoza VMT. Bleaching of vital teeth: technique.
Estomodeo 1984; 9:7-30. 2. Feinman R,Goldstein R Garber D. Bleaching teeth. Quintessence Int 1987: 1:lO. 3. Garretson JE.A system of oral surgery. 6th Ed. Philadelphia: JB Lippincott, 1895.
Acknowledgment I thankAdele Dunne for her perseverence, hard work, and encouragementin the preparationof this paper.
76
History, Chemicals, Methods
Bleaching Record 1.
Name
2.
Patient's chief color complaint
Date
Age
3. Cause of staining ~~~~
4.
Preoperative color
~~
Shade tab in field
Patient's desired postoperative color 5. Informed Consent The patient is informed that there are no guarantees to degree of tooth lightening. Further
dental treatment may be required to lighten teeth and the patient is instructed to discontinue bleaching immediately if any problems are encountered. Patient Signature
6. Bleaching method: chemicals used Walking __ method & bleaching agent
Office
method & bleaching agent
Home
method & bleaching agent
7 . Bleaching chemicals used and dispensed:
Visit
Date
Arch
Bleach Used
1.
3. 4.
5. 6. 7.
8.
8. Postoperative analysis: 1. Color: preoperative -postbleacNng 2.
Recommend rebleachings
3. Patient complaints
9. Further esthetic treatment includes:
Figure 1. Sample of bleaching record.
77
Amount Dispensed
Complaints
SO. Iiunsakrr KJ. Christensen G J , Christensen RP. Tooth
4. Cohen S . Parkins F M UIea(.hing trtrac.srlinr-st~tinedvital teeth. Oral Surg 1970: 29:165-171. 5. H a b ~ v o t dVU. tieymann IiO. Nightguard vital bleaching. Quintessence I n t 1989: 20: 173-1 76. 6. Croll T. Enamel mic~roabrasionfor removal of superficial discoloration. J Esthet Dent 1989; I : 14-20. 6A. &ens D. Personal communication. 1992. 6B. Haywood \B, He?mann €30.Nightguard vital bleaching. Quintessence lnt 1989: 20: 173- 176. 7. Chandra S. Chawla TN. Clinical evaluation of the sandpaper disr method for remoiing Iluorosis stains from teeth. J Am Dent Assoc 1975: 90:1273-1275. 8. U’q-nian J. Porteous JR. Tetracycline staining of teeth: a report on clinical material. J Dent Res 1963: 42: 11 111112. 9. LVainib*ghr \V, Lemoine F. Rapid diffuse penetration of intact enamel and dentin by carbon 14-labeled urea. J Am Dent Assoc 1950; 11:135. 10. Bartelstone HJ. Radioiodine penetration through intake with uptake by blood stream and thyroid gland. J Dent Res 1951; 30:72a733. 1 1. Bodes. L‘gu-uneri.Penetration of pulp chamber by hydrogen peroxide after \%a1 bleaching. J Endodont 1987; 131:375-377. 12. Hall D. Should etching be performed as a part of a vital bleaching technique. Quintessence Int 1991; 22(9):679686. 13. Croll T. Enamel microabrasion for removal of superficial dysmineralization and decalcification defects. J Am Dent Assoc 1990; 120. 14. Killian C. Croll T. Enamel microabrasion to improve enamelsurface texture. J Esthet Dent 1990;2(5):125-128. 15. Enamel microabrasion. CRA 1990; 14(11). 16. Rosenstiel S. GeGauff A, Johnson W. Duration of tooth color change after bleaching. J Am Dent Assoc 1992; 123:54-59. 17. Rosenstiel S, GegauffA, McCafferty R. Johnson W. Invitro tooth color change with repeated bleaching. Quintessence Int 1991; 22(1):7-12. 18. Ruse ND. Smith DC. Tomeck CD. Titley KC. Preliminary surface analysis of etched, bleached, and normal bovine enamel. J Dent Res 1990: 69(9):1610-1613. 19. Titley KC. Tomeck CD. Smith DC. Adibfar A. Adhesion of composite resin to bleached and unbleached bovine enamel. 1 J Dent Res 1988; 67:1523-1528. 20. Haywood V. Nightguard vital bleaching. a history and productsupdate: Part 1. EsthetDentUpdate 1991:2(4):63-66. 2 1. Munro J.Vital bleaching using the white and brite system. Esthet Dent Update 1990; 1(3):4349. 22. Haywood V. Leech T. Heymann H, Crumpler D, Bruggers K. Niteguard vital bleaching: effects on enamel, surface texture and diffusion. Quintessence Int 1990; 21 :801-804. 23. Haywood V. Nightguard vital bleaching: current information and research. Esthet Dent Update 1990; 1(2):20-25. 24. Archambault G. Caution, informed consent remains important as home bleachinggrows. Dent Today 1990;April: 16.22. 25. ADA News. May 21, 1990. 26. Tooth bleaching, home-use products. CRA Newsletter 1989: 13(7):1-2. 27. Haywood V. Personal communication, 1991. 27A Freedman G . The safety of tooth whitening. Dent Today 1990; April132-33. 28. Weitzman SA, WeitbergAB. StosselTP, SchwartzJ. Shklar G. Effects of hydrogen peroxide on oral carcinogenesis in hamsters. J Periodontol 1986 57(11):685-688. 29. Cvitko E, Denehy G,Swift E. Pires J. Bond strength of composite resin to enamel bleached with carbamide peroxide. J Esthet Dent 1991; 3(3):100-102.
bleaching chemicals’ influrnce on teeth and restorations. J Dent Res 1990; 69:303 (Abstr 1558).
K.Treatment of discolored teeth by means of neutral carbaniide peroxide bleachinggel. Six-month research report. University of Manitoba. Winnipeg. Manitoba. Product review. Esthet Dent Update 1990; 1(3):53-54. Bailey K. Christen A. Bleaching ofvital teeth stained with endemic dental fluorosis. Oral Surg 1968; 26:87 1. Munin J R . Barkmeier WM. Chemical treatment of vital teeth with intrinsic stain. Quintessence Int 1982: 13:6. Kuhns C. Discussion at 14th Meeting of the Dental Association of Lower Saxony. July 8. 1888. Dtsch Mschr Zahn Heilk 1888: 6:446-447. Newbrun E. Fluoride and dental caries. 3rd Ed. Springfield IL; Thomas Publishing. 1986:4. Black GV, McKay FS. Mottled teeth. Dent Cosmos 1916; 58: 129. McCloskey R. A technique for removal of fluorosis stains. J Am Dent Assoc 1984; 109:63-64. Bouschor CF. Bleaching of fluorosis stained teeth. NM Dent J 1965; 16:33. Mclnnes J. Removing brown stain from teeth. Ariz Dent J 1966; 12:13. Mello HS. The mechanism of tetracycline staining in primary and permanent teeth. J Dent Child 1967; 34:478. Seltzer S, Bender TB. The dental pulp. Philadelphia: 1965:25. Storey E. Experimental tetracycline administration. J Dent Res 1963; 42:5. Arens D. Rich J. Healy H. A practical method of bleaching tetracycline-stained teeth. Oral Surg 1972; Nov; 812-817. Compton D. Bleaching of tetracycline-stained vital teeth. J Endodont 1979; 5(5):1. Schwachman H, Schuster A. The tetracyclines applied pharmacology. Pediatr Clin North Am 1956; 3:295. Zegarelli EV. Denning C. Kutscher A. Tuoti F, di SantAgnese P. Discoloration of teeth in patients with cystic fibrosis of the pancreas. NY State Dent J 1961: 27:237. Falkensten RG. Effective bleaching technique forremoving tetracycline stains. Dent Surv 1977; Aprik46-54. Abou-Rass.M.Whitening teeth from inside out. DentToday 1985; Feb:37-38. Anbitua E. Zablegui B, Gil J. Gascon F. Internal bleaching of severe tetracycline discolorations. Four year report. Quintessence Int 1990; 21(10):183-188. Ledoux W, Malloy R, Hurst R. L e d o u P. Structural effects of bleaching on tetracycline-stained vital rat teeth. JPD 1985; 54(1):55-59. Seale NE. McIntosh JE. Taylor AN. h l p a l reaction to bleaching of teeth in dogs. J Dent Res 1981; 60:948. Jordan RE, Boksman L. Conservative vital bleaching treatment of discolored dentition. Compend Contin Educ Dent 1984: 5:803-808. Feinman R, Goldstein R, Garber D. Bleaching teeth. Chicago, IL: Quintessence, 1987: 20-22. Black JB. Esthetic restoration of tetracycline-stained teeth. J Am Dent Assoc 1982; 104:846. Jordan R. Esthetic composite bonding. Toronto: BC Decker, 1986:106. Garretson JA. System of oral surgery. 6th Ed. Philadelphia: J B Lippincott. 1985. Nutting EB. Poe GS. A new combination for bleaching teeth. Dent Clin North Am 1970; 655-662. Latcham NL. Management of a patient with severe postbleaching cervical resorption: a clinical report. JPD 1991; 65(5):603-605.
3c14 Jordan
31.
32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 51A
52. 53. 54.
55.
56. 57.
78
This article re\$ews the histow of bleaching teeth to lighten tooth color. The last 2 years have seen a dramatic increase in new bleaching methods and bleaching chemicals. The following categorizes bleaching chemicals and methods in relation to their use in treating common tooth discolorations. Special attention is given to home bleaching methods.
History of Tooth Bleaching
Need for Bleaching
1877 - Chapple's first published dental report on tooth bleaching using oxalic acid.' 1884- Harwan uses hydrogen peroxide as a bleaching agent.2 1895 - Garretson uses chlorine to bleach nonvital teeth.3 1916- Walter Kaine bleaches fluorosed teeth using muriatic acid (18% HC1 acid).2 1918-Abbot uses 35% hydrogen peroxide accelerated by heat from a light source.' 1970 - Cohen is first to bleach tetracycline-stained teeth using 35% H,02 and a bleaching instrument.' 1984 - Zaragoza bleaches maxillary and mandibular arches simultaneously with 70% H,O, + heat.' 1989 - Haywood and Heymann describe home bleaching using carbamide p e r o ~ i d e . ~ 1989 - Croll introduces hydrochloric acid paste system for superficial enamel discoloration.6
Fluorosis stains have a tremendous psychological effect on the patient and can be as disfiguring as a cleft lip or a facial scar.' Tetracycline tooth discoloration causes great anguish for children in a society that places a high value on appearance.8The dental profession has an obligation to treat tooth discoloration in the most conservative manner possible. In many cases tooth bleaching is the method of choice based on conservation of tooth structure and its effectiveness in lightening tooth discoloration.
Bleaching Process Superfiial Enamel Stains Superficial enamel stains are amenable to discing, acid erosion, and various peroxide solutions and methods. Deep enamel defects are best treated restoratively. Enamel-Dentin Stains Enamel-dentin stains are amenable to bleaching based on hydrogen peroxide's ability to penetrate both enamel and dentin to somehow liberate, oxidize, or break down stain molecules. Hydrogen peroxide's ability to lighten tooth color is not fully understood. Reports of diffuse penetration of intact enamel and dentin include:
Safety During the 113years of reported tooth bleaching in the dental literature, there is not one report of tooth brittleness fracture orpulpal necrosis. Employingproper bleaching methods can be both safe to the patient and effectivein lightening tooth color. Goldstein and kens report that heat bleaching a combined 40,000 teeth over 20 plus years has yielded neither pulpally damaged or fractured teeth.6A
1. In 1950Wainwright and Lemoine found substances of small molecular size, such as carbon- 14 labeled urea, diffused from the enamel surface to the pulp in 2 hour^.^ 2. In 1951 Bartelstone placed radioactive iodine on the tip of a cat incisor and found tagged iodine in the dental pulp within a short time.Io 3. In 1987 Bowles and Ugwuneri exposed the labial enamel surfaces of extracted pulpectomized teeth to 1%, lo%, and 30% H20,.All percentages were found to enter the pulp space within 15minutes."
'Private practice, Pleasant Hill. California. Dr. Fasanaro is also affiliated with the Postgraduate Bonding Practicum at the University of Pacific School of Dentisby. San Francisco, California Address reprint requests to Tom S . Fasanaro. D.D.S.. 70 Doray Drive. Pleasant Hill. CA 94523 0 1992 Decker Periodicals Inc.
71
though color relapse is common. However, the difficulty to patient and dentist has reduced its use to an adjunct to home bleaching in my practice. I have not found heat bleaching nearly as effective as home bleaching and use it only for single teeth such as dark cuspids.
Chemical Throy I . Enamel a] Acid pastes: permanently dissolve superficial enamel surface. 2. Enamel/Dentin a] Hydrogen peroxide: 2H,O, 2H,O + 2H'and for brief periods forms the perhydroxyl free radical HO,. which is enormously reactive with great oxidative power. I The free radical may break up the large macromolecular stain into smaller stain molecules and by diffusion expel them to the surface. It is also thought to attach to the molecular stain in the inorganic structure as well as protein matrix. b) H,O, -* H,O + 0, -+
Home Bleaching In more than 2.5 years and with 100 patients undergoing treatment, I have found this to be an extremely promising technique. Two plus shade improvements for yellow color (aging)have been seen in about 50-100 hours of bleaching time. More difficult yellow-grey tetracycline has taken 3 months and approximately 350 hours and yielded good improvement. During this period we have encountered little difficulty concerninghard or soft tissue other than transient cold sensitivity and soft tissue imitation caused by the bleaching splint. I consider home bleaching to be clearly the method of choice for tooth lightening and a milestone in the history of esthetic dentistry.
1 H'
+ HO; perhydroxyl free radical capable
of oxidizing tooth discoloration c) Pre-etching tooth with 30% phosphoric acid does not enhance bleaching results.'*
Patient Profile
TOOTH BLEACHING C HEMICALS
This is perhaps the most important aspect ofbleach-
ing treatment. Under no circumstances do we get a
Enamel Discoloration
lW?o result: usually we produce an improvement. There are no guarantees, and this must be candidly related to patients before they consent to treatment. Poor candidates include perfectionists, those who want whiter than white teeth, thosewith teeth that have large pulps, those with sensitive teeth, those with leaking restorations, sensitive root surfaces, and extremely dark stains, as well as patients who are not prepared for the rigors ofbleachingtreatment. Baseline photographic records employing a shade tab pre- and postoperatively against the teeth to be bleached are essential to verify tooth lightening and for future reference (Fig. 1).
Hydrochloric acid pastes and various H,O, methods can permanently remove superficial enamel discolorations. Use hydrogen peroxide bleaching agents for overall enamel discolorations caused by fluorosis. Should discoloration be limited to specific areas, then acid pastes are a conservative alternative. In some cases, both methods are employed. Hydrochloric acid pastes can permanently remove superficial enamel brown spots, white enamel opacities, and multicolored tooth surface defect^.^,^^.'^ Concentric super white areas are the result of hypocalciflcation and may extend to the dentinal border. They are best treated with bonded composite restorations. The recently introduced Croll system, Prema, is a major step forward:
Overview (Personal Experience) Nonuital Bleaching Nonvital bleaching has yielded dramatic color improvement over the last 2 1 years: however, it is impossible to predict or match the color of surrounding teeth. Retreatment approximately every 2 years is often required due to color relapse.
1. Extremely effective for superficial white enamel opacities, ortho bracket demineralization, multicolor yellow to brown stains, and irregular surface texture. 2. Employs 1O:l reduction handpiece (1000 rpm) to keep stiff acid paste confined to reduce splatter as well as a hand applicator for specific areas. 3. Versus disc or burr enamel surface removalmethod. HCl acid paste limits surface loss and creates a uniform appearance and is preferred to simple tooth reduction. 4. Precautions: Tooth isolation is mandatory to avoid soft tissue bums. Enamel surface loss is approximately 0.2mm. Checkanterior teethincisally every 10 seconds to monitor enamel removal. Five to seven applications are maximum. 5. Should the acid-paste system be ineffectivefor deepcolor defects, restorative options can be considered. l5
Fluorosis Over the last 8 years yellow to brown stains have yielded predictable removal of discoloration using a mild HF acid (Stripit) and thick prophylaxis paste delivered with stiff polishing cups and brushes. The recent introduction of the Croll Bleaching System is a great step forward. Should overall tooth lightening be required, as is often the case, I prefer H,O, home bleaching and the acid paste system for any localized areas not bleached.
Vital Bleaching I have bleached vital teeth using 35%H,O, and heat for 8 plus years. In all cases I have found improvement, 72
History, Chemicals. Methods
Dentin Discoloration
b) This amounts to approximately 1 1940H,O,. I find little need for these adjunct products as home bleaching alone works very well.
Overall dentin discoloration is commonly seen in nonvital teeth, with tetracycline ingestion. and in tooth aging.
Home Bleaching Hydrogen Peroxide 1.5Oh H,O,-Peroxyl. This is sold over the counter and bleaches slowly. 6%H,O,-Natural White. Rinse teeth with acetic acid for 20 seconds: apply 6% H,O,with cotton swab to teeth 1-2 minutes. Advertised as needing only 3 minutes per day; no mouthguard used. 2°h/50h/10% H,O,-Brite Smile. This is an officemonitored, at-home bleaching system using a vacuumformed tray. The dentist adjusts 35% H,O, with a .05% neutral sodium fluoride gel: progressive 2-5-10% solutions are introduced to the patient if there are no problems to accelerate process. If sensitivity to 10% solution occurs, they go back to the 5.0% solution. Recommended for 3 hours per day in a mouthguard; results are seen in 2-6 weeks. It employsa mucoprotectant for tooth isolation.
Offie Bleaching Hydrogen Peroxide 25% H,O, + no heat (e.g., Denta-Lite Plus). 35% H,O, +heat. The classic method employs light as a heat source and requires a rubber dam for tooth isolation. It is laborious for both patient and dentist when bleaching maxillae or mandible. It generally requires multiple treatments for most discolorations. Used for over 60 years 3 5 O h HzO, + heated instrument works well for 1 to 4 teeth such as dark cuspids, and requires a rubber dam or paint-on material for tooth isolation. Two recent studies noted initial lightness after one heat bleaching treatment that had reversed almost entirely at 1 month. l6 Subsequent bleachings resulted in a modest lightening effect" (e.g., Superoxol and Bleaching Light and/or Instrument, Union Broach). 35% H,O, + no heat + silicone dioxide thickener. "his is a new method that does not employ rubber dam or heat. Rather, it isolates teeth and protects gingivae with vaseline or a paint-on acrylic. The heavy gel is applied chairside for 20 minutes for nonvital teeth and 30 minutes for vital teeth. Multiple treatments may be required (e.g., Starbrite - Paint On Gingival Protectant, Bleachmaster, Pro-Brite, Accel, Studio 35). Note: 60 minutes of 35% H,O,did not change the elemental composition of bovine enamel.l 8 However, bond strength to resin is diminished.Ig 35% H,O, + curing light is a new powder-liquid system that is chemically (8-10 min) and curing-light activated in 2-3 minutes. It employs tooth isolation and is ideal for single tooth application, spot bleaching, or tetracycline band lightening (e.g., Hi Lite). 70% q O , + heat (officebleaching - B.V. Bleaching Vital System).'
Carbamide Peroxide Synonyms are urea peroxide, urea hydrogen peroxide, perhydrolurea, hydrogen peroxide carbamide, percarbamide. Carbamide peroxide was used in World War I as an anti-inflammatory antiseptic and in World War I1 to treat trench mouth. It has been used by dentists since 1960 for an oral wound debridement. In the 1960s Klusrnier noted tooth lightening using Gly-Oxide to assist post-traumatic tissue healing.,O Clinical reports of tooth lightening during gingivitis treatment using carbamide peroxide stimulated its use for tooth lightening. The current method was also described by John Munro who started his research in 1985for a medicine to accelerate wound healing post periodontal scaling.21 In March, 1989, Haywood and Heymann published their first article on home bleaching.6BCarbamide peroxide is marketed over the counter as Gly-Oxide(Marion Laboratories) and Proxigel (Reed and Carnrick). It is classified as an oral antiseptic by the FDA Monograph of 1974 along with 1.5 and 3.0% H,0,.23 Marion Laboratories has reported one adverse reaction in 30 years of Gly-Oxide use.24 Content is generally 10% carbamide peroxide, 88% glycerin, stabilizers, thickeners, and flavoring^:^^ it may or may not contain carbopol. Chemistry: 10% carbamide peroxide breaks down to 6.4% urea + 3.6% H,O,. The urea further breaks down to carbon dioxide and ammonia. The H,O, breaks down to H,O + 0, and liberates the chemically reactive free radical H0,- perhydroxyl for short periods.
1. The system was developed by Vincent Zargoza, M.D., D.D.S. (Spain) and employs custom-fitted thermotrays (4045°C): both maxillae and mandible can be bleached simultaneously. The soft tissues are isolated by paint-on acrylic. 2. 1-10 sessions, light yellow to violet. 3. Chemicals a) Enamel preparation-30% orthophosphoric acid, organic solvent, and ether. b) Soft tissue isolation. Cyanoacrylate. c) Bleach-7Ph H,O,, surfactants, amoniac hydroxide, persulphates, H,O. 4. Ten years of research were done in Spain, showing remarkable tooth lightening. I t was recently introduced in the U.S. as the BV-BleachingVitdSystem. 5. It may ultimately be the method of choice for greyblue tetracycline discoloration.
Urea Peroxide CH,N,O*H,O,
Carbamide Perodde a) 35% + no heat. Used as a start-up to home bleachingwith carbamideperoxide (e.g., Quick Start).
1
5
NH,
HzO,
+
CO,
73
5
H++HO;
1. Decided lightening in all cases without exception. 2. Most pronounced effect in the first 2 weeks, con-
1. The low molecular weight of peroxide allows it to
trayel freely through enamel and dentin.14 Staining may be due to disturbances in both organic and inorganic tooth formation. The oxygen-free radicals attach to the inorganic [stain)material on the teeth. The osidation of the organic (protein] double bond in theenamel, and outerlayers ofdentin, may break stain into smaller molecules. Stains are described a s macromolecular aliphatic chains located in interprismatic spaces and cracks. Oxygen bubbling enhances physical removal of the 2. Some home bleaching products employ carbopol (carboxypolmethylene pol-mer] to thicken carbamide peroxide to improve tooth adherence. It slows oxygen release 2.5 times longer than non-carbopolcontaining solutions (Proxigel patent). Both solutions work equally well.23Fluoride may also slow the bleaching process.L6 3. 10% carbamide peroxide yields 3.6%H,O,, while 15% carbamide peroxide yields 5.4% H,O,. 4. The life Of (Curs brochure) is 2-3 months. Always keep bleach refrigerated.
tinuing over a 3-month period. 3. Little if any change after 3 months. 4. Severe discoloration resists treatment. 5. Long-tem are unknown. Method A clear .020 (.5mm) vacuum-formed plastic splint
mouth-guard is constructed and trimmed a t or above the cementoenameljunction (CEJ).Die spacer increases comfort and may accelerate tooth lightening, but reduces retention. Change the bleaching solution hourly or with Carbopol every 3 or 4 hours: remove for meals and at night. Maximum treatment time is approximately 6 weeks or 300 hours. Recall weekly and monitor soft tissue and tooth structure; discontinue if any discomfort. Preserve casts for duration of treatment.23 Patient is instructed to keep a detailed diary of hours used, amount of bleach used in mL, and any complications encountered. This information is used for dental records, result evaluation, and future reference (Fig. 1). Postoperative Complications The majority of postoperative complications are related to tight-fitting splints and soft tissue abrasion upon splint removal. Sore areas include gingivae,tongue, and lips2’Swallowing of bleach may yield a sore throat or laxative effect due to glycerin content.23Other effects include cold or sweets sensitivity, discomfort due to sore teeth occluding on mouthguard. In the presence of soft-tissue inflammation, the gingivae may become ulcerated (deepithelialized).One report showed dissolution of composite resin matrix at 36 hours (White & brite, Proxigel).26The patient is instructed to discontinue if any side effects or difficulties occur.23 The appliance may require adjustment, or treatment should be stopped for 1-2 days until symptoms resolve. If no further problems are encountered, bleaching treatment is restarted. Contraindications include severe stain, severe enamel hypoplasia, pregnant or lactating women, hypersensitive teeth, known allergy to peroxide or glycerin, or lack of patient compliance to bleaching protocol.
Preliminary data indicate carbamide peroxide is nonmutagenic. LD 5.0-6.5 liters of Proxigel and 8 liters of Gly-O~ide.,~ Reviewing 20 articles covering 45 years, one author studying carbamide peroxide’s use as an oral antiseptic found it safe. An orthodontic study examining carbamide peroxide’s effect on caries over 3 years and approximately 1500 hours found no side effects.,’*A 1986study by Weitzman using 30% H,O, in the cheek pouch of hamsters over 22weeks found mild dysplasia in 50% of the a n i m a l ~ . ~ ~ L o n g - t etissue rm biocompatibility is not known at this time. Carbamide peroxide does not affect enamel surface texture, and no etching was apparent.22However, one study showed home bleaching reduced bond of composite to etched enamel. Removing surface enamel restored bond strength ~ o m p l e t e l yThere . ~ ~ is no noticeable effect on porcelain, resin, amalgam, or gold,30nor any incidence of permanent pulpal damage.23Bleaching appears to move laterally and lighten overall tooth color of teeth previously veneered with composite or porcelain, although the color of composite or porcelain does not lighten.22Therehas been stabilization of tooth lightening over 2 years,21although teeth do not always bleach evenly. The degree of lightening is directly related to the length of time the oxidizing agent is in contact with the teeth.31 Carbamide peroxide works very well on mild yellow, brown. or orange stains due to aging, fluorosis, tetracycline ingestion, and smokers’ stain. Extremely dark blue-grey stains will resist the bleaching process. The CRA Newsletter states that Dentlbright, Gly-Oxide,and Peroxyl bleach teeth more slowly than other products.26 In a 6-month study on home bleaching 6-8 hours per day by Ron J ~ r d a n ~ ~ * w40 i t hpatients at the University of Manitoba in Winnipeg, the following results occurred:
Available Products Carbamide peroxide products include the following:
a) 10% Carbamide Peroxide No Carbopol-Gly-Oxide, Denta Lite,White & Bright With Carbopol-Proxigel, Rembrandt Lighten, Dentlbright, Opalescence, Ultra-White, Smile Light, Ultra Lite Presaturated tray-Vital White b) 11% Carbamide Peroxide Enamelble~h~systemSmile~t,ADHBleaching Gel I c) 15%Carbamide Peroxide N u Smile
74
History, Chemicals. Methods
d)
16%Carbamide Peroxide ADH Bleaching Gel 11
1975 - Chandra and Chawla use 35% H,O, + 18% HCI + 5.25% sodium hypochlorite with fine cuttle discs. Stains were entirely removed with no reports of sensitivity.; 1984 - McClosky uses 18% hydrochloric acid + pumice +water to form a paste and applied with prophy cup. Also employs a cotton-tipped instrument in a light erasing motion, followed by a HCl paste on a prophy cup. He reported permanent stain removal."' 1989 - Croll introduces a 10% HCl paste system.n 1990 - US.400 areas in 28 states report enamel fluor~sis.~~
Over-the-counter (OTC)bleaching agents are quite unpredictable and potentially dangerous. I personally find bleaching toothpastes to be unnecessary and soft tissue response an unknown. A recent report of a 13year-old using an OTC bleaching product resulted in severe enamel erosion of the lingual surface of his maxillary anterior teeth. The product contained citric acid (CDA Journal, Sept.. 1991). Conclusion Home bleaching is the simplest bleaching method for significant lightening of enamel and dentinal discoloration: 2 + shade lightening in 4 to 5 days in many cases. Tooth structure lightens behind restorative veneers. There is much less discomfort than traditional 35% H,O, and heat. The long-term effects on soft tissue, color relapse, effect on restorative material and cements are not known at this time.
EuaIuation of Bleaching Method Stains are limited to outer enamel, precluding the necessity of hydrogen peroxide unless overall tooth lightening is required. The disc method of stain removal tends to remove excessive enamel. Therefore, acid abrasion pastes at slow speed orwith hand instrumentation yield a conservative method for permanent discolorized stain removal. Simple Stain - Intermittent white spotting or irregular brown stains. Prognosis: good Stains withRtting- Dark stain with surface deposits. Prognosis: dark stain responds well; severe pitting requires composite bonding. OpaquelOpalescent - Flat grey or white specks. Prognosis: difficult. Consider H,O, bleaching.
TYPES OF TOOTH DISCOLORATION Enamel Discolorations:Fluorosis Ingestion of > 1ppm fluorideduring the third month of pregnancy through the eighth year of life may result in enamel hypoplasia and staining. Ameloblasts are susceptible to > 1 ppm fluoride: 4 ppm yields severe discoloration. Fluoride is thought to affect improper calcification and a defective matrix f o r m a t i ~ nThis .~~ results in a well-mineralized enamel surface and a porous enamel Fluoride stains are limited to the outer one third of er~amel.~A common source of mild fluorosis today is from children swallowing fluoridated tooth paste while brushing, in addition to ingestion offluoridated water, rinses. or supplements (JADA, Vol. 122, Sept. 1991).
Precautions HCl leaves a dull surface that remineralizes in about 90 days. Transient cold sensitivity is normal (may require 1 4treatments.) Silky white patches are deeply ~ e a t e d deep : ~ hypoplastic defects require restorative treatment. Neutralize acid spills with sodium bicarbonate:37stimulate surface remineralization with a fluoride home rinse. Tooth isolation is mandatory.
Dentin: Tetracycline Stain
History of Fluorosis 1888- Kuhns describes black flecks in the enamel of the teeth of a family from Durango, 1901 - J. M.Eager notes enamel defects and black teeth among inhabitants near Naples.% 1901 - Fredrick McKay investigates tooth staining in Colorado Springs.35 1916- McKay and Greene Vardiman Black publish clinical findings of "mottling."36 1916 -Walter Kaine bleaches fluorosed teeth with muriatic acid (18% hydrochloric acid), alcohol, and a heated bleaching in~trument.~' 1931 - Churchill scientifically W s fluoride in water in Bauxite, Arkansas, to enamel discolorations. 1937 - Ames uses 5 parts 100% H,O, + 1 part anesthetic ether with a heated instrument. 1942 - Younger uses 5 parts 30% H,O, + 1 part anesthetic ether + heated in~trument.~' 1965- Bouschor on brown stains uses 5 parts 30% H,O, to 5 parts HC1 acid + 1 part anesthetic ether.39 1966 - McInness repeats Bouschor technique.32
Ingestion of tetracycline from the fourth month of pregnancy through the seventh year of life. The teeth forming at this critical period are the anterior teeth and are primarily limited to dentin matrix, which is also forming at the time., Fluorescent particles of tetracycline are thought to chelate to calcium in the mineralizing dentin at the hydroxyapatite surface40and are embedded in the collagen fibrils, which become the matrix for dentin Tetracyclines remain in dentin but rapidly disappear from Each dose taken yields a separate and individual stain.43The total mass of tetracycline is unlikely to exceed a few micrograms (BeMett. 1966).In 1963,yellow stain was linked to tetracycline a n d grey-brown to chlortetracycline.8Prolonged exposure to sunlight increases disc~loration.~~ Diagnosis: Positivefluorescence by Woods UV light.43
History of Tetracycline Bleaching 1948 - Tetracycline antibiotics are produced by soil organisms and used to combat cystic fibrosis, penicillinresistant organisms, and chronic bronchitkM 75
History
1956- Schwarhman reports tooth stain with tetra-
1895 - Garretson used chlorine to bleach nonvital teeth.55 1967 - Nutting and Poe introduce "walking bleach," 30% H,O, + perborate.g"
cycline 1 96 1 -Zegarelli confirms tetracycline stain in cystic fibrosis pa tien ts.*" 1963 - FDA adlrised physicians to use caution in
prescribing tetracycline during years of tooth formation.*' 1970 - Cohen and Parkins first attempt at bleaching tetracycline stains on cystic fibrosis patients.' 1977 - Falkensten uses 30% H,O, + 10% HCI acid one minute pre-etch + 100watt light bulb ( 1 04 deg F).47 1979 - Compton uses 3 5 O / 0 H20, + Indiana University bleaching instrument (130-145" F).4* 1985 - Abou-Rass combines endodontic therapy with internal bleaching emplo-ying 30% H,O, and 4-5 treatments &?thina 2-week period that yielded excellent esthetic results.lhAnother study showed a t 4years that only 6 of 258 teeth had slight color change ( r e l a p ~ e ) . " ~ 1990 - Combination. It is possible today to use heated 3 5 O h H,O,, unheated 35% H,O,. carbamide peroxide home bleaching separately or in combination. Evaluation of Bleaching Method Hydrogen peroxide is the bleaching agent of choice. The H,O, molecule penetrates enamel and dentin to liberate or alter the tetracycline molecule.50A short bleaching time, a carefully monitored heat source, if used, minimizes potential pulp damage.51I prefer home bleaching in most cases because of patient comfort and superlor results. Jordan and Boksman Tetracycline Stain Classi$cation5'*- Employing the 35% H,O, + Heat (Light)52
Evaluation of Bleaching Method It is very difficult to match existing tooth color: many treatments may be required. 1. Conservative lingual access. 2. Remove gutta percha below the cementoenamel
junction CEJ . 3. Place insoluble glass ionomer plug a t CEJ or above the surrounding bone height. Note: Diffusion of H,O, laterally below C E J has been linked to external res~rption.~' 4. 30% H,O, + perborate are placed in pulp space and sealed, changed weekly and repeated as necessary to lighten tooth color (e.g., 1-4 treatments). Note: After placing pellet, wait 5 to 10 minutes for hydrogen gas bubbling to end before placing temporary fill. 5. Etching coronal pulp and heated instruments are optional. 6. Seal lingual access with glass ionomer restorative. Lingual restoration should not employ etching and composite bonding as removal for futureretreatment is extremely difficult. 7. Repeat approximately every 2 years or as needed. Precautions Note: Postendodontic medicaments, sealing pastes, ZnO left in coronal pulp can yield discoloration. Lingual amalgam restorations to close endodontic access can create a silver oxide stain that is not bleachable.
I - Uniform light yellow, brown, or grey conflned to incisal3/4. Prognosis: good - 3 or less treatments: I1 -deep yellow, brown, or grey no banding. Prognosis: fair - 3 to 6 treatments: 111 - Dark grey or blue with marked banding. Prognosis:resists bleaching.53Up to 10treatments; and W - Severe stainsnot bleachable. Prognosis: PFM or endodontic therapy plus walking bleach.
Aging Discoloration As secondary dentin progressively obliterates the pulp space, tooth color progressively darkens (18 years old - A2: 40 years old - A3; 60 years old - A4 +). Historically, teeth have received 35% H,O, + heat, PFM, or porcelain veneer restorations. To treat discoloration from aging, I prefer home bleaching. The method is not difficult, and the results are dramatic for yellow, yellow-red, or brown discoloration.
Precautions Careful patient evaluation, well-sealed restorations, nonsensitive teeth, and total tooth isolation are primary considerations.
Hemorrhagic Discoloration
REFERENCES
Pulp necrosis creates blood breakdown products. If the cause of pulp necrosis is not caused by trauma but rather caries, there is a progressive protein degradation, which yields a greyish-brown discoloration.*Traumatic pulp death is thought to drive red blood cells into dentinal tubules hydraulically. The red blood cells undergo hemolysis producing a yellow-brown discoloration as the iron degrades to iron sulphide." Pinkorange-yellow-brown-blue or black - the severlty of discoloration is in proportion to the time between pulpal death and treatment.
1. Zaragoza VMT. Bleaching of vital teeth: technique.
Estomodeo 1984; 9:7-30. 2. Feinman R,Goldstein R Garber D. Bleaching teeth. Quintessence Int 1987: 1:lO. 3. Garretson JE.A system of oral surgery. 6th Ed. Philadelphia: JB Lippincott, 1895.
Acknowledgment I thankAdele Dunne for her perseverence, hard work, and encouragementin the preparationof this paper.
76
History, Chemicals, Methods
Bleaching Record 1.
Name
2.
Patient's chief color complaint
Date
Age
3. Cause of staining ~~~~
4.
Preoperative color
~~
Shade tab in field
Patient's desired postoperative color 5. Informed Consent The patient is informed that there are no guarantees to degree of tooth lightening. Further
dental treatment may be required to lighten teeth and the patient is instructed to discontinue bleaching immediately if any problems are encountered. Patient Signature
6. Bleaching method: chemicals used Walking __ method & bleaching agent
Office
method & bleaching agent
Home
method & bleaching agent
7 . Bleaching chemicals used and dispensed:
Visit
Date
Arch
Bleach Used
1.
3. 4.
5. 6. 7.
8.
8. Postoperative analysis: 1. Color: preoperative -postbleacNng 2.
Recommend rebleachings
3. Patient complaints
9. Further esthetic treatment includes:
Figure 1. Sample of bleaching record.
77
Amount Dispensed
Complaints
SO. Iiunsakrr KJ. Christensen G J , Christensen RP. Tooth
4. Cohen S . Parkins F M UIea(.hing trtrac.srlinr-st~tinedvital teeth. Oral Surg 1970: 29:165-171. 5. H a b ~ v o t dVU. tieymann IiO. Nightguard vital bleaching. Quintessence I n t 1989: 20: 173-1 76. 6. Croll T. Enamel mic~roabrasionfor removal of superficial discoloration. J Esthet Dent 1989; I : 14-20. 6A. &ens D. Personal communication. 1992. 6B. Haywood \B, He?mann €30.Nightguard vital bleaching. Quintessence lnt 1989: 20: 173- 176. 7. Chandra S. Chawla TN. Clinical evaluation of the sandpaper disr method for remoiing Iluorosis stains from teeth. J Am Dent Assoc 1975: 90:1273-1275. 8. U’q-nian J. Porteous JR. Tetracycline staining of teeth: a report on clinical material. J Dent Res 1963: 42: 11 111112. 9. LVainib*ghr \V, Lemoine F. Rapid diffuse penetration of intact enamel and dentin by carbon 14-labeled urea. J Am Dent Assoc 1950; 11:135. 10. Bartelstone HJ. Radioiodine penetration through intake with uptake by blood stream and thyroid gland. J Dent Res 1951; 30:72a733. 1 1. Bodes. L‘gu-uneri.Penetration of pulp chamber by hydrogen peroxide after \%a1 bleaching. J Endodont 1987; 131:375-377. 12. Hall D. Should etching be performed as a part of a vital bleaching technique. Quintessence Int 1991; 22(9):679686. 13. Croll T. Enamel microabrasion for removal of superficial dysmineralization and decalcification defects. J Am Dent Assoc 1990; 120. 14. Killian C. Croll T. Enamel microabrasion to improve enamelsurface texture. J Esthet Dent 1990;2(5):125-128. 15. Enamel microabrasion. CRA 1990; 14(11). 16. Rosenstiel S. GeGauff A, Johnson W. Duration of tooth color change after bleaching. J Am Dent Assoc 1992; 123:54-59. 17. Rosenstiel S, GegauffA, McCafferty R. Johnson W. Invitro tooth color change with repeated bleaching. Quintessence Int 1991; 22(1):7-12. 18. Ruse ND. Smith DC. Tomeck CD. Titley KC. Preliminary surface analysis of etched, bleached, and normal bovine enamel. J Dent Res 1990: 69(9):1610-1613. 19. Titley KC. Tomeck CD. Smith DC. Adibfar A. Adhesion of composite resin to bleached and unbleached bovine enamel. 1 J Dent Res 1988; 67:1523-1528. 20. Haywood V. Nightguard vital bleaching. a history and productsupdate: Part 1. EsthetDentUpdate 1991:2(4):63-66. 2 1. Munro J.Vital bleaching using the white and brite system. Esthet Dent Update 1990; 1(3):4349. 22. Haywood V. Leech T. Heymann H, Crumpler D, Bruggers K. Niteguard vital bleaching: effects on enamel, surface texture and diffusion. Quintessence Int 1990; 21 :801-804. 23. Haywood V. Nightguard vital bleaching: current information and research. Esthet Dent Update 1990; 1(2):20-25. 24. Archambault G. Caution, informed consent remains important as home bleachinggrows. Dent Today 1990;April: 16.22. 25. ADA News. May 21, 1990. 26. Tooth bleaching, home-use products. CRA Newsletter 1989: 13(7):1-2. 27. Haywood V. Personal communication, 1991. 27A Freedman G . The safety of tooth whitening. Dent Today 1990; April132-33. 28. Weitzman SA, WeitbergAB. StosselTP, SchwartzJ. Shklar G. Effects of hydrogen peroxide on oral carcinogenesis in hamsters. J Periodontol 1986 57(11):685-688. 29. Cvitko E, Denehy G,Swift E. Pires J. Bond strength of composite resin to enamel bleached with carbamide peroxide. J Esthet Dent 1991; 3(3):100-102.
bleaching chemicals’ influrnce on teeth and restorations. J Dent Res 1990; 69:303 (Abstr 1558).
K.Treatment of discolored teeth by means of neutral carbaniide peroxide bleachinggel. Six-month research report. University of Manitoba. Winnipeg. Manitoba. Product review. Esthet Dent Update 1990; 1(3):53-54. Bailey K. Christen A. Bleaching ofvital teeth stained with endemic dental fluorosis. Oral Surg 1968; 26:87 1. Munin J R . Barkmeier WM. Chemical treatment of vital teeth with intrinsic stain. Quintessence Int 1982: 13:6. Kuhns C. Discussion at 14th Meeting of the Dental Association of Lower Saxony. July 8. 1888. Dtsch Mschr Zahn Heilk 1888: 6:446-447. Newbrun E. Fluoride and dental caries. 3rd Ed. Springfield IL; Thomas Publishing. 1986:4. Black GV, McKay FS. Mottled teeth. Dent Cosmos 1916; 58: 129. McCloskey R. A technique for removal of fluorosis stains. J Am Dent Assoc 1984; 109:63-64. Bouschor CF. Bleaching of fluorosis stained teeth. NM Dent J 1965; 16:33. Mclnnes J. Removing brown stain from teeth. Ariz Dent J 1966; 12:13. Mello HS. The mechanism of tetracycline staining in primary and permanent teeth. J Dent Child 1967; 34:478. Seltzer S, Bender TB. The dental pulp. Philadelphia: 1965:25. Storey E. Experimental tetracycline administration. J Dent Res 1963; 42:5. Arens D. Rich J. Healy H. A practical method of bleaching tetracycline-stained teeth. Oral Surg 1972; Nov; 812-817. Compton D. Bleaching of tetracycline-stained vital teeth. J Endodont 1979; 5(5):1. Schwachman H, Schuster A. The tetracyclines applied pharmacology. Pediatr Clin North Am 1956; 3:295. Zegarelli EV. Denning C. Kutscher A. Tuoti F, di SantAgnese P. Discoloration of teeth in patients with cystic fibrosis of the pancreas. NY State Dent J 1961: 27:237. Falkensten RG. Effective bleaching technique forremoving tetracycline stains. Dent Surv 1977; Aprik46-54. Abou-Rass.M.Whitening teeth from inside out. DentToday 1985; Feb:37-38. Anbitua E. Zablegui B, Gil J. Gascon F. Internal bleaching of severe tetracycline discolorations. Four year report. Quintessence Int 1990; 21(10):183-188. Ledoux W, Malloy R, Hurst R. L e d o u P. Structural effects of bleaching on tetracycline-stained vital rat teeth. JPD 1985; 54(1):55-59. Seale NE. McIntosh JE. Taylor AN. h l p a l reaction to bleaching of teeth in dogs. J Dent Res 1981; 60:948. Jordan RE, Boksman L. Conservative vital bleaching treatment of discolored dentition. Compend Contin Educ Dent 1984: 5:803-808. Feinman R, Goldstein R, Garber D. Bleaching teeth. Chicago, IL: Quintessence, 1987: 20-22. Black JB. Esthetic restoration of tetracycline-stained teeth. J Am Dent Assoc 1982; 104:846. Jordan R. Esthetic composite bonding. Toronto: BC Decker, 1986:106. Garretson JA. System of oral surgery. 6th Ed. Philadelphia: J B Lippincott. 1985. Nutting EB. Poe GS. A new combination for bleaching teeth. Dent Clin North Am 1970; 655-662. Latcham NL. Management of a patient with severe postbleaching cervical resorption: a clinical report. JPD 1991; 65(5):603-605.
3c14 Jordan
31.
32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 51A
52. 53. 54.
55.
56. 57.
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