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Inside Dentistry

April 2006, Volume 2, Issue 3
Published by AEGIS Communications


Considerations for Enhancing Efficacy and Comfort With In-office Tooth Whitening: A Case Report

Delon Gilbert, DDS; Bruno DaCosta, DDS

The most common and minimally invasive way to quickly enhance the appearance of a smile is in-office tooth whitening. According to the American Academy of Cosmetic Dentistry, tooth whitening is currently the most prescribed esthetic dental procedure, and many whitening options are now available. However, dentist-monitored treatments remain the recommended procedures for lightening discolored teeth.1

Aging, disease, medications, food, tobacco use, and beverages may all cause tooth discoloration.2,3 Fluorosis, tetracycline use, and/or developmental defects may lead to intrinsic discoloration; extrinsic stains result from localized reactions in the pellicle.3

The success of tooth whitening efforts depends on the concentration of the whitening agent used, the duration of its use, and the type of tooth discoloration with which the patient presents.2,4,5 The literature reports successful results when whitening intrinsically stained teeth—even those with severe tetracycline staining—using 35% hydrogen peroxide for in-office power whitening or 10% to 15% carbamide peroxide for at-home whitening.3,6

When determining the most appropriate whitening regimen for patients, it is imperative that clinicians consider three aspects of treatment: (1) potential patient sensitivity, (2) the efficacy of the proposed whitening agents, and (3) the manner in which these two considerations are accounted for in the whitening options available.7 This article briefly outlines the factors contributing to these considerations and presents a tooth whitening case that was completed using a recently introduced in-office tooth whitening system that, in the authors’ opinions, attempts to target the needs of both patients and clinicians.

SENSITIVITY

Reported side effects of in-office tooth whitening (as well as take-home and over-the-counter products) include tooth sensitivity and gingival irritation.4,5 The use of an active potassium nitrate and fluoride desensitizing agent was studied during tooth whitening in a population at risk for tooth sensitivity, and it has been suggested that its use may decrease tooth sensitivity.8 Other research has demonstrated that when amorphous calcium phosphate is added to a professional 16% peroxide whitening gel regimen, postprocedure tooth sensitivity, soft tissue health, and gingival health remain similar to baseline levels.6,9

Tooth sensitivity in the tooth whitening process has also been related to tooth dehydration.10 Such dehydration has been associated with an improper pH balance, and it has been proposed that whitening agents should be formulated with a pH balance that would not be detrimental to enamel or dentin.6,11

LONG-TERM EFFICACY

Numerous studies have demonstrated that nightguard vital bleaching is safe and effective and provides long-term shade retention when 10% carbamide peroxide is used.4 Light-activated, in-office whitening using a 35% hydrogen peroxide-based gel has also been proven effective, demonstrating uniform whitening to the depth of dentin.12 Other studies have indicated that the addition of amorphous calcium to peroxide whitening gel regimens produces 10% better long-term whitening efficacy (ie, shade retention) than the traditional whitening gel.6,9

It is important to note, however, that although researchers disagree regarding the actual benefits of exclusive “tooth whitening lights,” there is research to support light activation to increase the lightening effects of peroxide, even in concentrations as low as 15%.6,13 Researchers found that peroxide and light activation significantly whitened tooth color to a greater extent than peroxide or light alone, and with low and transient occurrence of tooth sensitivity.13

CURRENT WHITENING OPTIONS

As a result of patient sensitivity to whitening treatments, methods for speeding the whitening process and making it more comfortable and convenient have been developed. The use of activating agents to enhance the whitening effects of hydrogen peroxide in combination with natural enzymes has been proposed.3,6 To this end, the positive effects of chemical catalysts added to whitening gels have been demonstrated in clinical research.14 Additionally, current in-office whitening techniques take advantage of whitening agents specifically formulated with catalysts that react with and/or are activated by light, and investigations have found that color changes are significantly affected by the interaction of bleach with light variables.15 The premise is that, ideally, the in-office whitening procedure can be shortened while still achieving the desired whitening effects.

In response to clinicians’ and patients’ needs, a new in-office whitening system has been introduced (GC TiON™ Tooth Whitening System, GC America, Alsip, IL), which includes a nitrogen doped titanium dioxide photocatalyst (V CAT™, Toyota Tsusho Corporation, Florence, KY) that, according to the manufacturer, promotes better in-office whitening in a shorter period of time using a lower concentration of hydrogen peroxide (20%).6 It is believed that this lower hydrogen peroxide concentration contributes to less patient sensitivity, while the photocatalyst produces better whitening when it is activated with any commercially available bleaching light or dental curing light.6 Additionally, the formulation of the whitening agent is pH balanced and, therefore, less likely to demineralize the teeth (it is anticipated that this will also lessen patient sensitivity). However, to further minimize the likelihood of sensitivity, as well as to help ensure the long-term efficacy of the whitening results, this whitening system also includes an after-whitening paste, which contains bioavailable calcium and phosphate.6

CASE PRESENTATION

A 25-year-old man presented for tooth whitening to remove stains resulting from coffee drinking and smoking (approximately 10 cigarettes daily) (Figure 1). A thorough examination was performed, which included radiographs and intraoral photographs. No pathologies were found that would contraindicate vital in-office tooth whitening using a new in-office, light-activated whitening system (GC TiON Tooth Whitening System). In particular, care was taken to ensure the absence of any exposed dentin or enamel fractures.7 Using the classic Vita® shade tabs (Vident, Inc, Brea, CA), the patient’s prewhitening shade was determined to be A3.5 (Figure 2).

The tooth surfaces were cleansed using the nonfluoride prophy paste provided with the whitening system (Figure3). Care was taken to not exceed 5,000 rpm during prophylaxis.6

A cheek and lip retractor was placed, along with cotton rolls and a facial mask to prevent contact of the whitening gel with the patient’s skin.6 The teeth were dried with air, and the curable, liquid gingival protector supplied with the whitening system was placed. Preventing accidental exposure of the gingival tissues to whitening solutions has been advocated in the literature.7 The gingival protector was applied to a 1-mm to 2-mm thickness, covering 4 mm to 5 mm apically from the gingival margin, according to the manufacturer’s instructions (Figure 4). Because it has also been advocated to avoid whitening the cervical area of the tooth by covering the area with a base to avoid cervical resorption,7 approximately 0.5 mm of protector was applied to the tooth surface adjacent to the gingival margin. Once thoroughly placed, the gingival protector was cured for 10 to 20 seconds using a 400 nm to 500 nm curing light.6

In preparation for whitening, the whitening liquid and gel were thoroughly mixed in the whitening gel syringe according to the manufacturer’s instructions until the desired viscosity was achieved. The ideal consistency can easily be placed on the tooth surface without slumping or running, which further minimizes the risk of contact with gingival and soft tissues.

Simultaneously, the whitening reactor containing the unique photocatalyst was applied to each tooth surface in one thin layer using a disposable tip brush (Figure 5) and blown dry with an air syringe to remove any excess. The whitening gel was then syringed onto each tooth in a thickness of approximately 0.5 mm to 1.0 mm (Figure 6).

The patient was fitted with protective eyewear. To activate and initiate the whitening process, the patient was placed under a plasma arc curing light with a bleaching diffuser for 20 minutes (Sapphire™, Den-Mat Corporation, Santa Maria, CA) (Figure 7). After light activation, the whitening gel was removed, working from the cervical to the edge using gauze. The bleaching gel application and activation process was completed 2 additional times, each for 20 minutes.

When the entire whitening treatment was completed and all of the whitening gel was removed (Figure 8), the results of the whitening process were visible and determined to be shade B1. The gingival protector was removed (Figure 9), and a paste containing bioavailable calcium and phosphate (PROSPEC™ MI Paste, GC America, Inc, Alsip, IL) was applied to the teeth with a prophy cup. For maximum desensitization effect, and also to ensure shade stability, this paste was allowed to remain in place for 5 minutes. The paste was then rinsed off, and the cheek and lip retractor and cotton rolls were removed (Figure 10).

CONCLUSION

When considering which whitening alternatives to incorporate into the practice, it is incumbent upon clinicians to identify those products that have at their core scientific research that supports the rationale for their formulations and theoretically supports their safety and efficacy claims. Although clinical evaluations are necessary to ascertain the long-term safety and efficacy of the specific in-office tooth whitening system used in this case, its overall results include the successful lightening of the patient’s teeth from a shade A3.5 to a shade B1 in a minimal amount of time (ie, 60 minutes) and with a low concentration of whitening agent (20%) (Figure 11). The patient reported no tooth or gingival sensitivity either during or after the process and shade stability was documented during the recall visit (Figure 12). Considering that gingival and tooth sensitivity are commonly occurring side effects of any type of tooth whitening, and that the literature advocates limiting whitening time to maintain pulp vitality,7 identifying and then verifying the validity of in-office tooth whitening choices can help clinicians best serve their patients’ needs for conservative, immediate esthetic enhancement.

Acknowledgment

The authors would like to thank their dental assistant, Mindy Rode, for her assistance in completing this case.

REFERENCES
1. American Academy of Cosmetic Dentistry. An introduction to your smile. http://www.aacd.com/public/intro.aspx?MenuArea=Public. Accessed February 23, 2006.

2. Watts A, Addy M. Tooth discoloration and staining: a review of the literature. Br Dent J. 2001;190(6):309-316.

3. Viscio D, Gaffar A, Fakhry-Smith S, et al. Present and future technologies of tooth whitening. Compend Contin Educ Dent. 2000;(suppl 28):S36-S43.

4. Leonard RH JR, Bentley C, Eagle JC, Garland GE, et al. Nightguard vital bleaching: a long-term study on efficacy, shade retention, side effects, and patients’ perceptions. J Esthet Restor Dent. 2001;13(6): 357-369.

5. Auschill TM, Hellwig E, Schmidale S, et al. Efficacy, side-effects and patients’ acceptance of different bleaching techniques (OTC, in-office, at-home). Oper Dent. 2005; 30(2):156-163.

6. Milnar FJ. Enhancing the efficacy and patient comfort associated with combination in-office and take-home tooth whitening: a case report. Dent Today. 2005. In press.

7. Powell LV, Bales DJ. Tooth bleaching: its effect on oral tissues. J Am Dent Assoc. 1991;122(11):50-54.

8. Leonard RH Jr, Smith LR, Garland GE, et al. Desensitizing agent efficacy during whitening in an at-risk population. J Esthet Restor Dent. 2004;16(1): 49-55.

9. Giniger M, Spaid M, MacDonald J, et al.A 180-day clinical investigation of the tooth whitening efficacy of a bleaching gel with added amorphous calcium phosphate.J Clin Dent. 2005;16(1):11-16.

10. Kugel G, Ferreira S. The art and science of tooth whitening. J Mass Dent Soc. 2005;53(4):34-37.

11. Sulieman M, Addy M, Macdonald E, et al. A safety study in vitro for the effects of an in-office bleaching system on the integrity of enamel and dentine. J Dent. 2004;32(7):581-590.

12. Sulieman M, Addy M, Macdonald E, et al. The bleaching depth of a 35% hydrogen peroxide based in-office product: a study in vitro. J Dent. 2005;33(1): 33-40.

13. Tavares M, Stultz J, Newman M, et al. Light augments tooth whitening with peroxide.J Am Dent Assoc. 2003;134(2):167-175.

14. Hein DK, Ploeger BJ, Hartup JK, et al. In-office vital tooth bleaching—what do lights add? Compend Contin Educ Dent. 2003;24(4A): 340-352.

15. Luk K, Tam L, Hubert M. Effect of light energy on peroxide tooth bleaching. J Am Dent Assoc. 2004;135(2):194-201.

Figure 1 Prewhitening view of the patient in natural smile. Figure 2 Retracted prewhitening view revealing tooth discoloration. The prewhitening shade was A3.5.
Figure 3 A nonfluoride prophy paste was used before whitening to thoroughly clean the tooth surfaces. Figure 4 A light-cured gingival protector was placed and cured for 10 to 20 seconds.
Figure 5 A thin layer of whitening reactor was applied to the surface of each tooth to be whitened. Figure 6 The whitening gel was syringed onto each tooth in a thickness between 0.5 mm and 1 mm.
Figure 7 The patient was placed under the whitening light for 20 minutes to activate the whitening process. Figure 8 The whitening gel was removed from each tooth, moving from the cervical to the edge.
Figure 9 The gingival dam and all cotton rolls were removed. Figure 10 Immediate postwhitening results after application and removal of a paste containing bioavailable calcium and phosphate.
Figure 11 View of the patient’s postwhitening results at the 24-hour recall appointment. Figure 12 The patient’s successful whitening result was determined after 24 hours and found to be shade B1.
About the Authors
Delon Gilbert, DDS
Private Practice
Portland, Oregon
Bruno DaCosta, DDS
Private Practice
Portland, Oregon

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