Whiter Teeth, Younger Look

Dental consumers, concerned with achieving a youthful facial image, look to tooth whitening to enhance their overall appearance. Vital tooth whitening methods remain one of the most requested dental procedures available. The sale of professionally-dispensed whitening products has increased from $435 million in 2000 to $2 billion in 2005.¹ Over-the-counter tooth whitening sales made up approximately 1.5 billion in 2006.¹ Regardless of their present oral health status, patients want to know their options when it comes to brightening their smiles. Thus, dental hygienists need to be knowledgeable on the types, safety, advantages, and disadvantages of professionally-dispensed, take home whitening products and their use.

PROFESSIONALLY-DISPENSED WHITENING AGENTS

Professionally-dispensed whitening involves the in-office fabrication of a custom mouth tray, selection of an appropriate whitening agent, and detailed instructions on dispensing the product into the tray via a syringe for a prescribed frequency and period of time. The dental professional monitors the patient at various intervals to determine whitening progress until a reasonable result is achieved.²

Professionally-dispensed whitening contains either hydrogen peroxide or carbamide peroxide as its active ingredient. In water (the mouth), carbamide peroxide breaks down to urea and hydrogen peroxide. A whitening product containing 10% carbamide peroxide is comparable to another product that contains 3.3 % hydrogen peroxide.²

SIDE EFFECTS

Professionally-dispensed whitening products can have notable physical and chemical side effects and are nontherapeutic. Negative side effects may include dentinal hypersensitivity, gingival irritation, and loss of vital tooth structure. The steady use of whitening products for long periods of time can cause a decrease in enamel hardness.³ Professionally-dispensed whitening is the preferred method when used according to professional recommendation and under the care of a dental professional, mainly due to product innovations that prevent common problems associated with whitening treatment, such as dentinal hypersensitivity and loss of enamel.²

Since dental insurance usually will not cover cosmetic procedures, tooth whitening is an out-of-pocket expense for most dental patients. Cost for custom trays can range from about $150 to $300, totaling approximately $300 to $600 for both the maxillary and mandibular arches.³ In addition, the cost of syringes ranges from about $10 to $15 each. Clinical outcomes are not permanent and patients will require periodic whitening maintenance, which brings time and cost commitments for patients.

Studies examining the loss of enamel after professionally-dispensed whitening procedures vary. Some report that the use of professional whitening gel could reduce enamel hardness. Haywood notes that enamel hardness is only vulnerable in high concentrations of whitening gel, ranging from 16% to 35% ­carbamide peroxide as opposed to 10% solutions.⁴ Pro­fessionally-dispensed whitening gel contains 10% to 15% carbamide peroxide.⁴

Studies have compared the hardness levels of both enamel and dentin after tooth whitening using both in-office and at-home concentrations. Results, analyzed using the Knoop hardness test, showed that both the in-office 35% concentration and professionally-dispensed at home 15% concentration decreased the hardness of enamel and dentin. Although the in-office percentage decreased enamel and dentin hardness more than the professionally-dispensed at home formula, both caused significant loss of vital tooth structure.⁵

Basting assessed seven different brands of carbamide peroxide professionally-dispensed whitening products on loss of enamel over time. Of the seven concentrations that ranged from 10% to 22%, all showed decreased enamel hardness as measured by the Knoop hardness test after 8 hours of treatment. Products containing fluoride in their whitening products may yield a significant increase in enamel hardness.⁶

Reports of sensitivity remain common during and after professional whitening treatments, so product selection is important, especially for patients with a history of hypersensitivity. Participants in one study described less sensitivity when using professionally-dispensed whitening as compared with in-office procedures.⁷ The majority of studies found that dentinal hypersensitivity is reversible since all symptoms dissipate once treatment is complete.^4,7

The addition of the compound amorphous calcium phosphate (ACP) reduces the incidence of tooth sensitivity when added to whitening gels. Originally developed for enamel remineralization and to arrest the dental caries process, ACP forms hydroxyapatite through a crystallization process.⁸ When the calcium and phosphate combine, the newly formed ACP accelerates onto tooth structure and can mix with saliva for remineralization.⁹

Gingival irritation is another common side effect of professionally-dispensed bleaching gels. Next to dentinal hypersensitivity, gingival irritation is one of the most reported side effects with up to two thirds afflicted. Usually the irritation resolves itself after the whitening product is removed, but in some cases the problem can persist.²

BENEFITS

Studies show that a more attractive smile can make a person more successful in his or her career, more attractive to a mate, and may even serve as a motivational factor to cut unhealthy oral behaviors, such as smoking.⁷

A study conducted on a population of older adults (minimum age of 50 years old) showed that those participants who whitened their teeth with the 14% hydrogen peroxide solution reported a significant increase in tooth color satisfaction when compared at baseline, 3 weeks, and 3 months later.¹⁰

Giniger determined that 16% carbamide peroxide whitening gel with ACP (0.5% soluble calcium and phosphate from calcium nitrate and potassium pyrophosphate) contributed to significantly fewer reports of tooth hypersensitivity, without any detrimental effect on tooth whitening outcomes. Specifically, no differences were noted in tooth color from the gel with ACP compared to the placebo (gel without the ACP)—both products were equally effective in whitening teeth.⁸

THE PROCEDURE

The first step of professionally-dispensed, take home whitening is the dental examination. During this time, the dentist will determine the patient’s current shade and decide which shade is possible to achieve with the whitening product. Also during the initial examination, the dentist will check to see if the patient has any anterior tooth colored restorations, since hydrogen or carbamide peroxide will not whiten these materials. If these materials are present and the patient still wants to proceed with the whitening process, the dentist can replace the restorations after the whitening process, but this must be explained to the patient.

After the dental examination, a dental professional will take impressions, which are then used to create a positive working mold or cast of the patient’s mouth. The trays are fabricated from this cast and trimmed so they fit at the gumline. A third visit is needed to ensure the custom trays fit correctly and to dispense the whitening product and give instructions. Further appointments are made at the discretion of the dentist to monitor progress.¹¹

THE ROLE OF THE HYGIENIST

The dental hygienist plays a role in maintaining and monitoring side effects and long-term outcomes of professionally-dispensed, take home whitening. Appropriate oral health instructions must be provided that are specific to each patient’s individual concerns. The patient should be advised that certain beverages such as red wine, tea, coffee, cola drinks, and foods with natural and artificial dyes like blueberries, cause stains that can compromise the longevity of the tooth whitening procedure. Tooth staining can also occur from smoking, certain antibiotics, excessive amounts of fluoride during tooth development, and aging.¹² Certain oral rinses, eg, 0.12% chlorhexidine, some CPC-containing rinses, and some stannous fluoride compounds, will stain teeth and esthetic restorations. Products to assist in removing stains should be discussed with the patient. These may include power toothbrushes, whitening dentifrice, and whitening rinses. The dental staff should work as a team to monitor and maintain results after whitening procedures.

CONCLUSION

Professionally-dispensed whitening treatment has made promising technological advances. The at-home, professionally-monitored whitening procedure is an affordable, effective, safe, and painless procedure. Understanding the different whitening methods enables the dental hygienist to provide an evidence-based rationale when questioned by patients eager to have whiter teeth.

Additional research and development are needed to relieve gingival irritation that commonly occurs with professionally-dispensed whitening. Whitening research is currently investigating the effects of aqueous cleaning technology, which may be able to reduce some of the side effects that are associated with professionally-dispensed, take-home tooth whitening.¹³ New research and product development will be exciting to both the professional and consumer in the near future.

REFERENCES

1. Park P. Over-the-Counter Teeth Whitening: When Something So White Goes So Wrong. Available at: www.docshop.com/2007/04/20/at-home. Accessed April 24, 2008.
2. Gerlach RW, Zhou X. Vital bleaching with whitening strips: summary of clinical research on effectiveness and tolerability. J Contemp Dent Pract. 2001;2:1-16
3. Raposa K. The whitening generation: what you need to know to help your patients and your practice make the right decisions about tooth whitening. Access. 2006;20:24-31.
4. Leonard RH Jr, Haywood VB, Caplan DJ, et al. Nightguard vital bleaching of tetracycline-stained teeth: 90 months post treatment. J Esthet Restor Dent. 2003;15:142-153.
5. Lewinstein I, Fuhrer N, Churaru N, Cardash H. Effect of different peroxide bleaching regimens and subsequent fluoridation on the hardness of human enamel and dentin. J Prosthet Dent. 2004;92:337-342.
6. Basting R, Rodrigues A, Serra M. The effects of seven carbamide peroxide bleaching agents on enamel microhardness over time. Am J Dent. 2003;134:1335-1342.
7. Auschill T, Hellwig E, Schmidale S, Sculean A, Arweiler NB. Efficacy, side-effects and patients’ acceptance of Different bleaching techniques (OTC, in-office, at-home). Oper Dent. 2005;30:156-163.
8. Giniger M, Macdonald J, Ziemba S, Felix H. The clinical performance of professionally dispensed bleaching gel with added amorphous calcium phosphate. J Am Dent Assoc. 2005;136:383-392.
9. Competitive Calcium Phosphate Technologies, a Review. Available at: www.dentist.net/amorphous-calcium-phosphate.asp Accessed April 24, 2008.
10. Poindexter A, Darby M, McCombs G, et al. Vital Tooth Whitening Effects on Oral Health-Related Quality of Life. Unpublished masters thesis. Old Dominion University, Norfolk, 2007
11. Protocol for teeth whitening using tray-based tooth bleaching systems. Available at: www.animated-teeth.com/teeth_whitening/t4_tooth_bleaching.htm. Accessed April 24, 2008.
12. ADHA Oral Health Information. Tooth Whitening Systems. Available at: www.adha.org/oralhealth/whitening.htm. Accessed April 24, 2008.
13. Margeas R. New advances in tooth whitening and dental cleaning technology. RDH. 2006; 26(12):1-11.

From Dimensions of Dental Hygiene. May;6(5): 28, 30.