S10 Compendium / June 2000 Vol. 21, Supplement No. 28

CE 2Van B. Haywood, DMDProfessorDepartment of Oral RehabilitationSchool of DentistryMedical College of GeorgiaAugusta, Georgia

Current Status ofNightguard Vital Bleaching

Nightguard vital bleaching (NGVB) was first introduced in 1989.1 Itoriginally involved the application of 10% carbamide peroxide in athin custom-fitted tray. The patient wore the tray overnight or for sev-

eral hours during the day for 2 to 6 weeks (Figures 1A and 1B ). A decade ofresearch and clinical experience has added credibility to the technique andbroadened its scope.

Treatment ExpectationsFor maximum benefit of NGVB per application and compliance for long-

term treatment, the whitening tray should be worn at night. However, a mini-mum of 2 to 4 hours daily is the second option because the material is active for4 to 10 hours.2 Less than 2 hours wastes product and may extend treatment. Thelength of treatment varies from patient to patient. The average is 2 to 6 weeks,although it could be shorter. Nine out of ten patients achieve successful light-ening. Typically, the teeth lighten to a certain shade and then plateau. There isan initial color relapse upon completion because the residual peroxide in thetooth changes the optical qualities. Dentists should wait 2 weeks on color sta-bility for any restorative work and for bond strengths to achieve their maximumstrength before attempting bonded composite restoration.3

The duration of color stability without retreatment is generally 1 to 3 years,although it could be permanent. When evaluating the efficacy of NGVB after6 weeks of treatment, discoloration caused by aging, smoking, inherent stain-ing, brown spots, or single dark teeth were successfully removed in 97% of thesituations.4 At a follow-up of 13 to 25 months (average 18 months), 74% of thepatients had no noticeable change without retreatment. At 31 to 42 months(average 38.5 months), 62% reported no noticeable change without retreat-ment. And at 75 to 89 months (average 82 months), 35% reported no notice-able change from the time of treatment.

Product SafetyAlthough there were initial concerns about safety and efficacy, the guide-

lines established by the American Dental Association (ADA) have set the stan-

Learning Objectives:

After reading this article, the readershould be able to:

• describe the process of night-guard vital bleaching.

• list the indications and contraindications of at-homewhitening.

• discuss the treatment of side effects such as tooth sensitivity during whitening.

• discuss when and how to present tooth whitening topatients.

Abstract: Indications for using a 10% carbamide peroxide material in a cus-tom-fitted tray to whiten teeth include teeth discolored from aging, chro-mogenic foods and drinks, and smoking, and also brown fluorosis-stainedteeth, single dark teeth, and tetracycline-stained teeth. Tetracycline-stainsmay require 2 to 6 months of nightly treatment, whereas other discolorationsgenerally resolve in 2 to 6 weeks. After an initial relapse in the first 2 weeksafter the end of treatment, color tends to be stable for 1 to 3 years, with sometreatments being permanent. The ADA has approved only six 10% car-bamide peroxide materials, which have extensive research and publicationson safety and efficacy. Considering the average cost of $196 per arch, and thenoninvasive nature of this treatment, nightguard vital bleaching is probablythe safest, most cost-effective, patient-pleasing method to improve theappearance of a smile. However, it should be supervised by a dentist for theproper examination, diagnosis of the cause of discoloration, treatmentoptions, and fabrication and fitting of the carrier. Sensitivity during whiten-ing may be treated with fluoride and potassium nitrate.

dard for product safety.5 Currently, the ADAhas approved six 10% carbamide peroxideproducts: Rembrandt® Classica, Opalescence®,b,Nite White® Classicc, Platinum and PlatinumOvernightd, and Patterson Toothwhitening gele.These products have had extensive researchand clinical trials, and can be defended as safe.Manufacturers of these products cannot makeclaims that are not supported by scientificresearch or the products will lose the ADA seal.On the other hand, companies that do not havethe seal can make any claim about their prod-uct, some of which may be untrue. When theseclaims are presented by companies who do nothave the seal, there is no guarantee of theirtruth, or any way to challenge the companybecause the ADA seal is a voluntary program.

As a result of some false or misleadingclaims, I have limited my use and research toproducts with the ADA seal. With these prod-ucts, there is a large body of literature support-ing their safety and efficacy, and ADA sanc-tion for the public and dentists’ protection.However, companies that have the ADA sealon their 10% carbamide peroxide product maymanufacture other products of higher concen-trations or even the same concentration butdifferent composition that are not included bythe ADA seal. The dentist cannot assume thatall concerns have been addressed in the otherproducts until research is published.

Product CompositionVariations exist among carbamide perox-

ide products,6 including the concentration ofthe material, which can vary from below 10%up to 35%. A 10% solution of carbamide per-oxide is roughly 3% hydrogen peroxide and 7%urea. The base vehicle may be a glycerin, ananhydrous glycerin, a type of glycol, or even a

dentifrice. There are also different thickeners.Release time of the peroxide can be slow overa long period, quick initially but prolongedover a long time, or quick with no long-termrelease. Viscosity varies from a thick gel, tohoney-like, to a toothpaste-like cream. Thetray design varies with the material and thepatient. Soft-tissue response may vary amongproducts because of the stickiness and the watersolubility of the product. Retention in the traymay be altered by the water solubility of theproduct, influencing tray design. Delivery sys-tems vary from tubes to syringes to bottles.There are mild effects on restorative materials,but no color change will occur. The color of thewhitening material can vary from clear towhite, and different flavors are available.

Laboratory and Clinical Safety Laboratory research, generally associated

with ADA-approved products, has shown thesurface changes within normal variation forneutral pH solutions.7 Ten percent carbamideperoxide does not etch like phosphoric acid,although products with a low pH or high con-centration may affect the enamel surface. Thehardness of enamel is not affected by 10% car-bamide peroxide at neutral pH, nor is subsur-face hardness affected in the dentinoenameljunction.8 Minor effects on teeth are consis-tent with other normally occurring events. Forexample, the amount of calcium loss fromwhitening (in vitro) for 6 hours is the same asthe amount from contact with a soft drink for2.5 minutes, which is the approximate time ittakes to drink a 16-ounce soft drink.9

There is a long history of other uses of 10%carbamide peroxide.10 The most notable istreating thrush with 10 drops of carbamideperoxide on the tongue of a new-born infant atevery feeding for 7 days,11 which demonstratesthe safety from ingestion. It is also noteworthythat the body makes hydrogen peroxide andhas internal mechanisms for handling it.

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Figure 1A—Preoperative view demonstrating yellow inheritstaining from birth.

Figure 1B—Six weeks of 10% carbamide peroxide on the maxil-lary arch shows a dramatic change in color.

aDen-Mat, Santa Maria, CA 93456bUltradent Products Inc, South Jordan, UT 84095cDiscus Dental, Culver City, CA 90232dColgate Oral Pharmaceuticals, Canton, MA 02021ePatterson Dental, St. Paul, MN 55120

Important to understanding case selectionoptions and efficacy is that 10% carbamideperoxide easily and rapidly penetrates enameland dentin,12 allowing whitening underrestorations such as veneers and composites.Different concentrations of solutions eventual-ly yield the same color change, just at differenttreatment times.13 A significant color changeoccurs in dentin, in addition to what occurs inenamel.14 The change in dentin color explainsthat we are not only removing discolorationfrom extrinsic and intrinsic stains, but alsochanging the tooth’s baseline color.

Dentist SupervisionThis relatively safe procedure requires den-

tist supervision. First, the dentist must conducta complete examination to determine if thepatient is a good candidate.15 The examinationshould include medical and dental health,including the soft-tissue, temporomandibularjoint, and occlusal status; the history of the dis-coloration; and a diagnosis for the existingcolor. A prophylaxis may be needed to elimi-nate extrinsic stains. The diagnosis must elimi-nate abscessed teeth, existing caries, internal orexternal resorption, stained or metallic restora-tions, and translucency of the teeth.16 This diag-nosis may require radiographs to determine theexistence of periapical pathology, pulp size dis-crepancies, resorption or other pathologicalproblems, as well as pulp testing.17 The exami-nation should also identify all restorations visi-ble in the patient’s smile that may not matchafter whitening.18 Patients must be financiallyand mentally ready to replace restorations thatdo not match the final outcome, which is oftena contraindication for whitening.

After proper examination and diagnosis ofthe discoloration, the dentist can advise thepatient of the options for whitening, theexpected treatment time, costs, and side effects.The dentist can then determine the best tray

design and material for the patient, dependingon the patient’s concerns and history, as well astissue and bony architecture. The importanceof a custom-fitted tray cannot be over-empha-sized; it impacts patient comfort, reduces sideeffects, and maximizes efficacy. The dentaloffice has the best available materials for thetray material and the whitening material.

During insertion of the custom-fitted tray,the dentist ensures there is no irritation to thetissue and that the change in occlusion can besatisfactorily tolerated or adjusted accordingly.Finally, follow-up care for questions and treat-ment of side effects ensures the patient canhave a successful outcome. In addition, dentistsupervision is important because normal den-tal problems may arise during treatment.

Indications and Limitations of WhiteningIndications for whitening include teeth

discolored by aging, ingestion of chromogenicfoods and drinks, smoking, or being born withdiscolored teeth. The single dark tooth,whether vital or nonvital, is a good candidatefor whitening, as are some brown fluorosis-stained teeth. Tetracycline-stained teeth canhave a favorable prognosis, depending on thelocation and color of the stain. White spotscannot be removed, but whitening the rest ofthe tooth may make them less noticeable(Figures 2A and 2B). Brown stains can beeliminated about 80% of the time. Otherwise,some form of abrasion technique with possiblecomposite bonding is appropriate.19,20

The restrictions or limitations for bleach-ing are few. Generally, the age of the patientcan be as young as 10 years, when the perma-nent teeth have erupted. There are no report-ed cases involving primary teeth because theyare generally very white. However, we havehad success with primary teeth that were dark-ened from trauma (Dr. David Brantley, person-al communication). There is no upper limit for

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Figure 2A—White areas on teeth are highlighted by natural yel-low color of the teeth.

Figure 2B—After bleaching with 10% carbamide peroxide, thewhite is still present but less noticeable.

age, but older patients must accept that rootsurfaces remain darker when whitening. Theonly real restrictions to whitening are thenumber of existing restorations that may needreplacement, the severity of tooth sensitivity,problems with taste, or lack of compliance.Whitening is not offered to pregnant or nurs-ing mothers as a precaution, although there areno known adverse effects.

Side Effects During WhiteningThe most prevalent side effects are tooth

sensitivity and gingival irritation.21 Tooth sen-sitivity is most often cited, and can be chemical(reversible pulpitis) or mechanical (tray pres-sure). Generally, two out of three patientsexperience some sensitivity, which is mainlysporadic.4 There are no predictors for who willexperience sensitivity. It usually depends oninherent patient sensitivity (as determinedfrom the preoperative examination and histo-ry) and the frequency of application (morethan once per day increases sensitivity).22

Sensitivity has not correlated with age, gender,exposed dentin or cementum, cracks, pulp size,allergies, decay, or other patient factors.Contributors to sensitivity include rigid traymaterial, soft-tissue contact, the base vehicle,viscosity, flavors, or patient habits. Gingivalirritation, which is the lesser of the two sideeffects, is primarily mechanical (tray fit) or sec-ondarily chemical (tissue irritation). The aver-age duration on either side effect is 1 to 4 days,but not necessarily consecutive days. All sideeffects cease when treatment is terminated,with no reoccurrence or additional side effects.

Treatment of Tooth SensitivityTooth sensitivity can be treated passively

or actively. The passive approach includesreducing the time the tray is worn or frequen-cy of application, temporarily interruptingtreatment, or ultimately ceasing treatment.The active approach involves the applicationof two materials using the tray: a fluoride (neu-tral) or a 3% to 5% potassium nitrate.

The secret to treating sensitivity is the useof tray delivery for the desensitizing materials.

The tray material should be soft so it does notintroduce orthodontic forces, and the designmay or may not extend onto soft tissue.Fluoride has traditionally been applied as atubular blocker and can have good resultswhen used alone. However, potassium nitratehas been used extensively in desensitizingtoothpaste.23 Potassium nitrate penetrates thetooth and has a calming effect on the nerve.24

The tray delivery of potassium nitrate is mosteffective.25 Three commercial products containboth fluoride and 3% to 5% potassium nitrate:UltraEZ™,b, Desensitize!a, and Relief™,c. Inaddition, several brands of toothpaste, such assix varieties of Sensodyne®,f, Crest®

Desensitizeg, and Colgate® Sensitived containpotassium nitrate. Although the toothpastemay be more cost effective for patients in thelong-term treatment of sensitivity, some ingre-dients may irritate gingival tissues, requiring aswitch to commercially available products.

The treatment protocol for potassiumnitrate is to apply the material in the tray for 10to 30 minutes before or after whitening. Somepatients may only need to apply the potassiumnitrate when sensitivity occurs because somesensitivity may not occur until 8 hours aftercessation of treatment. Also, potassium nitratecan be used on alternate nights from thewhitening material. The success rate of allow-ing patients to continue treatment after usingpotassium nitrate in the tray has been 90%+.26

Although many whitening companies mayclaim to have eliminated or reduced sensitivity,there are no published reports to substantiatethis claim. In the general sensitivity reportsfrom clinical trials, the treatment group experi-enced 55% to 75% sensitivity, the placebogroup had 20% to 30% sensitivity, and a groupwearing the tray alone had 15% to 20% sensi-tivity.27 Percentages vary by tray design andmaterial, treatment time, and the manner inwhich questions were presented to participants.

Tray Design OptionsTray design options include reservoirs or

spacers on teeth and scalloping the edge toconform to the tooth-gingival interface. Res-ervoirs are not needed to whiten teeth, but theymay reduce sensitivity because they are nottight fitting. Reservoirs are most often neededwith sticky materials to allow complete seating

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f Block Drug Company, Jersey City, NJ 07302g Procter & Gamble Co, Cincinnati, OH 45202

The guidelines established by theADA have set the standard for

product safety.

of the tray. However, reservoirs may not beindicated on the mandibular teeth because ofocclusal interferences from vertical overlap.

The scalloped design, which may includethe entire tray or only portions of the tray, pre-vents the tray from contacting gingival tissueand causing irritation. This design is best withsticky viscous materials, but not with water-soluble materials. Nonscalloped trays elimi-nate tongue and lip irritation and maintainmaterial in the tray better than the scallopeddesign. When treating the mandibular arch,the nonscalloped design is often preferredbecause of the mobile tongue, salivary glandlocation, and the tendency for the material todrain from the inverted tray. Another tray, forpatients with temporomandibular disorder, isdesigned so that it does not extend onto theocclusal surfaces.28 This design can be usedonly with sticky viscous materials.

Treatment for Tetracycline-Stained TeethAfter learning that some nicotine stains

require 3 months of whitening, there have beenseveral clinical trials and reports on whiteningtimes beyond 2 to 6 weeks.29,30,31 When whiten-ing tetracycline-stained teeth, patients shouldcommit to a minimum of 2 to 6 months of treat-ment (Figures 3A, 3B, 4A, and 4B). When dis-coloration is located at the neck of the tooth,the prognosis is poorest; when it is dark gray orblue, the prognosis also is poor. However, allpatients who have tried this extended treatmenthave seen some lightening. Those who were notsuccessful were candidates for veneers, but nowthe veneers could be placed on a lighter tooth.Of those who were successful, 84% have main-tained the color change for 4.5 years with nointerim treatment.32

Although physicians are aware of thestaining potential of tetracycline drugs duringtooth formation, tetracycline is indicated forsuch diseases as Rocky Mountain SpottedFever and cystic fibrosis. However, fully

formed teeth in adults may be stained fromtaking the tetracycline Minocycline for acne.33

This discoloration can be caused from deposi-tion of tetracycline in the secondary dentin aswell as from soaking in saliva.

Presenting Whitening to PatientsWhitening can be offered as a stand-alone

treatment, but it must be done tactfully. Tryquestions such as, “Are you happy with yoursmile?” or “Is there anything you would like tochange about your smile?” If the dentist orpatient is uncertain whether bleaching wouldimprove the patient’s appearance, compare thesclera (whites) of the patient’s eyes to his or hertooth color. Beauty consultants state that for anatural appearance, the teeth should be as lightor lighter than the whites of the eyes.Whitening should be presented before anyrestorative treatment, and patients must beinformed of the options. If they decide againstwhitening, their chart should document that.After restorative treatment, there are options towhiten darker teeth to match lighter restorativematerials, but this treatment must be performedcarefully to achieve a proper shade match.

Some practitioners feel that they have tochoose between whitening and veneers. Theyfear that if the teeth are whitened and veneersare placed on those teeth, then the color mightregress, making the veneers unsuccessful.However, a recent report demonstrates thatteeth can be whitened from the lingual, whichshould allay those fears.34 It is always best toattempt whitening before veneers, either toeliminate the need for veneers or to obtain alighter tooth on which to place the veneers.

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Figure 3A—A mild form of tetracycline-stained teeth, the color ofwhich depends on the brand of tetracycline ingested.

Figure 3B—After 3 months of whitening with 10% carbamideperoxide, there is a noticeable change in the maxillary arch.

The secret for effectiveness intreating sensitivity is the use of

tray delivery for the desensitizingmaterials.

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There are many reasons patients whitenteeth: to look younger, to look healthier, tosmile more, to feel better about themselves, tohave better oral hygiene, and to be generallybetter looking. Reasons given for not whiten-ing teeth include: to look distinguished, safetyconcerns, because of extensive restorationsthat would require replacement, or poor self-concept. This procedure is elective, and it can-not be assumed that everyone wants it.

Fees and Other Treatment OptionsFees are primarily related to the amount of

chairtime required and office overhead. Totaltreatment time is an average of 3 appointments,or 1.5 to 2 hours of chairtime. The cost to thepatient should be less than that for 1 porcelainveneer. In 1999, the national average fee per archwas $196, although fees vary across the country.35

For patients being treated for tetracycline-stained teeth, most changes occur after thefirst 2 months of treatment, but to be fair toboth the dentist and the patient, the fee is notpredetermined because the treatment timecould be as long as 6 months.36 Patients pay aninitial fee for the first month’s treatment,which is generally the normal one-arch fee anduses all the material in a standard whiteningkit. Afterward, patients are seen on monthlyrecalls to determine progress and amount ofmaterial used, and they are assessed a monthlyfee for the examination and additional materi-al required for another month’s treatment. Inthis way, patients can pay as they go, and con-tinue as long as they see results.

Single-Arch TreatmentDuring the whitening research trials I have

conducted, many patients elect not to whitentheir lower arch, even when there is no fee. Forthat reason, I recommend all offices have a sin-gle-arch treatment fee. Allowing the patient to

experience whitening without a commitment tothe higher fee of both arches may reach a widernumber of patients. Also, single-arch treatmentallows comparison between arches for encourage-ment and compliance. There is also less chancefor side effects because fewer teeth and tissue arecovered and there is less impact on the occlusion.

In-Office Whitening While in-office whitening using 35%

hydrogen peroxide is still an option, it general-ly takes 2 to 6 appointments of 45 to 60 min-utes each to achieve the same results as at-home whitening.37 Appointments arescheduled a week apart to reduce sensitivity.Generally, the cost of one in-office appoint-ment is the same as the total cost for successfulat-home treatment, so the cost-benefit ratio ismuch better using at-home whitening.38 In-office whitening may be used as a start to at-home whitening, or for patients who cannot ordo not want to comply with at-home whiten-ing.39 Laser whitening, which has only beensanctioned by the ADA using the argon laser,40

has not been shown to be any more effectivethan conventional in-office whitening.41

Over-the-Counter Products and Other UsesToothpaste removes only extrinsic stains

by mechanical means; very little if any changein tooth color is possible. Over-the-counterand television advertised whitening productshave been shown at best to be ineffective, andsome are damaging to enamel.42

During whitening, the salivary pH elevatesabove 8 within 5 minutes and remains there forat least 2 hours,43 so additional uses for 10% car-bamide peroxide in tray delivery are being exam-ined. These include controlling root caries (withand without fluoride), treating mouth ulcers andmalodor, reducing chlorhexidine staining byalternating with the peroxide, and reducing

Figure 4A—A moderate form of tetracycline staining, along withan endodontically treated left central incisor restored with a Class4 composite restoration.

Figure 4B—Twelve months of whitening with 10% carbamideperoxide nightly, followed by replacement of the composite in theendodontically treated tooth yields a satisfactory result.

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CE 2plaque for patients with poor oral hygienebecause of mental or physical handicaps.

ConclusionsNightguard vital bleaching using 10% car-

bamide peroxide in a custom-fitted tray provid-ed by the dentist has proven to be one of themost cost-effective, patient-pleasing, dentist-friendly, safe, and effective treatments toimprove a patient’s smile. Use of the techniquerequires a proper examination, diagnosis, andtreatment plan relative to patient needs or con-ditions. The dentist should be aware of indica-tions and contraindications of the technique,as well as other treatment options that may berequired. The dentist should be knowledgeablein custom-fitted tray design options for specificwhitening materials and patient conditions,and in treating side effects during treatment.

References1. Haywood VB, Heymann HO: Nightguard vital bleaching.

Quintessence Int 20(3):173-176, 1989.2. Matis BA, Gaiao U, Blackman D, et al: In vivo degrada-

tion of bleaching gel used in whitening teeth. J Am DentAssoc 130(2):227-235, 1999.

3. Swift EJ Jr, Perdigao J: Effects of bleaching on teeth andrestorations. Compend Contin Educ Dent 19(8):815-820, 1998.

4. Haywood VB, Leonard RH, Nelson CF, et al: Effectiveness,side effects and long-term status of nightguard vital bleach-ing. J Am Dent Assoc 125(9):1219-1226, 1994.

5. American Dental Association Council on DentalTherapeutics: Guidelines for the acceptance of peroxide-containing oral hygiene products. J Am Dent Assoc125(8):1140-1142, 1994.

6. Haywood VB: Considerations and variations of dentist-prescribed, home-applied vital tooth bleaching techniques.Compend Contin Educ Dent 15(suppl 17):s616-s621, 1994.

7. Haywood VB, Heymann HO: Nightguard vital bleaching:how safe is it? Quintessence Int 22(7):515-523, 1991.

8. McCracken MS, Haywood VB: Effects of 10% carbamideperoxide on the subsurface hardness of enamel.Quintessence Int 26:21-24, 1995.

9. McCracken MS, Haywood VB: Demineralization effects of10 percent carbamide peroxide. J Dent 24(6):395-398, 1996.

10. Haywood VB: History, safety, and effectiveness of currentbleaching techniques and applications of the nightguard vitalbleaching technique. Quintessence Int 23(3):471-488, 1992.

11. Dickstein B: Neonatal oral candidiasis: evaluation of a newchemotherapeutic agent. Clinical Pediatrics 3(8):485-488, 1964.

12. Cooper JS, Bokmeyer TJ, Bowles WH: Penetration of thepulp chamber by carbamide peroxide bleaching agents. JEndod 18(7):315-317, 1992.

13. Leonard RH, Sharma A, Haywood VB: Use of differentconcentrations of carbamide peroxide for bleaching teeth:and in vitro study. Quintessence Int 29(8):503-507, 1998.

14. McCaslin AJ, Haywood VB, Potter BJ, et al: Assessingdentin color changes from nightguard vital bleaching. JAm Dent Assoc 130(10):1485-1490, 1999.

15. Haywood VB: An examination for nightguard vitalbleaching. Esthetic Dent Update 6(2):51-52, 1995.

16. Haywood VB: The Food and Drug Administration and itsinfluence on home bleaching. Current Opinion in CosmeticDentistry :12-18, 1993.

17. Haywood VB, Heymann HO: Response of normal and

tetracycline-stained teeth with pulp-size variation to night-guard vital bleaching. J Esthet Dent 6(3):109-114, 1994.

18. Haywood VB: Current status and recommendations for den-tist-prescribed, at-home tooth whitening. ContemporaryEsthetics and Restorative Practice 3(1):2-9, 1999.

19. Croll TP, Cavanaugh RR: Enamel color modification bycontrolled hydrochloric acid-pumice abrasion. I. Techniqueand examples. Quintessence Int 17(2):81-87, 1986.

20. Haywood VB: Bleaching and microabrasion options.Esthetic Dent Update 6(4):99-100, 1995.

21. Christensen GJ: Tooth bleaching: state-of-art ’97. CRANewsletter 21(4):1-3, 1997.

22. Leonard RH, Haywood VB, Phillips C: Risk factors for devel-oping tooth sensitivity and gingival irritation with night-guard vital bleaching. Quintessence Int 28(8):527-534, 1997.

23. Silverman G, Berman E, Hanna CB, et al: Assessing theefficacy of three dentifrices in the treatment of dentinalhypersensitivity. J Am Dent Assoc 127(2):191-201, 1996.

24. Markowitz K: Tooth sensitivity: mechanism and manage-ment. Compend Contin Educ Dent 14(8):1032-1046, 1992.

25. Jerome CE: Acute care for unusual cased of dentinal hyper-sensitivity. Quintessence Int 26(10):715-716, 1995.

26. Haywood VB, Caughman WF, Frazier KF, et al: Tray deliv-ery of potassium nitrate-fluoride to reduce bleaching sensi-tivity [abstract]. J Dent Res 79(3):519, 2000.

27. Leonard RH: Efficacy, longevity, side effects, and patientperceptions of nightguard vital bleaching. Compend ContinEduc Dent 19(8):766-781, 1998.

28. Robinson FG, Haywood VB: Bleaching and temporo-mandibular disorder using a half tray design: a clinicalreport. J Prosthet Dent 83(5):501-503, 2000.

29. Haywood VB, Leonard RH, Dickinson GL: Efficacy of sixmonths of nightguard vital bleaching of tetracycline-stained teeth. J Esthet Dent 9(1):13-19, 1997.

30. Haywood VB: Extended bleaching of tetracycline-stainedteeth: a case report. Contemporary Esthetics and RestorativePractice 1(1):14-21, 1997.

31. Haywood VB: Bleaching tetracycline-stained teeth. EsthetDent Update 7(1):25-26, 1996.

32. Leonard RH, Haywood VB, Eagle JC, et al: Nightguardvital bleaching of tetracycline-stained teeth: 54 monthspost treatment. J Esthet Dent 11:265-277, 1999.

33. Parkins FM, Furnish G, Bernstein M: Minocycline use dis-colors teeth. J Am Dent Assoc 123(10):87-89, 1992.

34. Haywood VB, Parker MH: Nightguard vital bleachingbeneath existing porcelain veneers: a case report.Quintessence Int 30(11):743-747, 1999.

35. National Fee Survey: quartile rankings. Dental Practice &Finance Nov-Dec:32. 1999.

36. Blankenau R, Goldstein RE, Haywood VB: The currentstatus of vital tooth whitening techniques. CompendContin Educ Dent 20(8):781-796, 1999.

37. Haywood VB: Nightguard vital bleaching and in-officebleaching. Contemporary Esthetics and Restorative Practice2(4):78-81, 1998.

38. Garber DA: Dentist-monitored bleaching: a discussion ofcombination and laser bleaching. J Am Dent Assoc128(Suppl):26S-30S.

39. American Dental Association Council on ScientificAffairs: Laser-assisted bleaching: an update. J Am DentAssoc 129(10):1484-1487.

40. Jones AH, Diaz-Arnold AM, Vargas MA, et al:Colorimetric assessment of laser and home bleaching tech-niques. J Esthet Dent 11(2):81-84, 1999.

41. Haywood VB, Robinson FG: Vital tooth bleaching with night-guard vital bleaching. Curr Opin Cosmet Dent 4:45-52, 1997.

42. Christensen RP, Ploeger BJ, Palmer TM, et al: Effect oflight and/or heat on vital tooth lightening. CRA Newsletter24(4):1-3, 2000.

43. Leonard RH, Austin SM, Haywood VB, et al: Change in pHof plaque and 10% carbamide peroxide during nightguardvital bleaching. Quintessence Int 25(12):819-823, 1994.