Dentifrices are not created equal

Sept. 1, 2000
The practitioner needs to reinforce to the patient that the (whitening) results are best maintained through professional supervision and excellent hygiene practices.

The practitioner needs to reinforce to the patient that the (whitening) results are best maintained through professional supervision and excellent hygiene practices.

Kristine A. Hodsdon, RDH, BS

Smile-enhancing procedures are of much interest to consumers, as indicated by the billion-dollar over-the-counter market for products that whiten and brighten. The mass marketing of over-the-counter (OTC) oral health products, however, easily confuses clients. In fact, they are so confused that they will trust their oral health to celebrities who sell products via infomercials or through other advertisements.

Dental professionals need to understand the indications and limitations of dentifrices and educate their clients in choosing the appropriate one for smile enhancement or preservation of esthetic treatment.

Allow a moment to revisit the makeup of dentifrices. Traditionally, they have active and inactive ingredients. Active ingredients perform a specific preventive or treatment action. Some examples may include chlorine dioxide, essential oils, zinc chloride, fluoride, peroxides, potassium nitrate, and zinc compounds. Inactive ingredients include cleansing agents, humectants, colors, preservatives, sweeteners, flavors, foaming agents, thickening agents, and buffering agents. Their purpose is to provide structure, texture, color, flavor, stability, and cleaning activity.

Now put yourself into the minds of your clients. They look into the mirror and smile. What do they perceive? Some may see their teeth as getting darker near the gingival line. Or a client may notice his natural teeth are yellow or exhibit a blue-gray tone. He may also observe teeth that are discolored due to age, smoking, a diet filled with dark-pigmented foods, beverages, or other behavior factors. Many clients see the "darker areas" and begin to self-treat with the purchase of a "whitening" toothpaste.

Hygienists who have graduated from an accredited dental hygiene program may determine that the darker areas are exposed cementum or dentin, or the darkening may be a combination of extrinsic and intrinsic stain. Extrinsic stain can be yellow, green, orange, brown, or black. It could also be undetected decay or calculus. Internal stain may be blue-gray or yellow stain - probably caused by chemicals or systemic medications - that is impregnated deep within the dentin.

As oral health leaders, hygienists can develop and implement a care plan to include an appropriate dentifrice to benefit their clients` individual oral health statuses and smiles.

Whitening toothpastes use four mechanisms in their attempt to change the color of teeth:

Y Abrasion

Y Chemical dissolution

Y Peroxide lightening

Y Cosmetic masking

Abrasives. Dentifrices usually contain a mixture of cleansing agents (20 to 40 percent silicas) to ensure efficient cleaning. Some abrasives do remove mild surface stains; however, the natural color of the dentition remains unchanged. The "whitening" is achieved through the removal of extrinsic stain and can lead to possible loss of tooth structure. This treatment is popular with the uninformed consumer. But its questionable result may be achieved at the expense of the enamel or dentin on exposed root surfaces.

Chemical dissolution. Chemicals have also been incorporated into dentifrices to enhance cosmetics. The first step of this twofold treatment is the chemical dissolution of the stains from the tooth surface. Secondly, crystal growth inhibitors (tetrasodium pyrophosphate, disodium dihydrogen pyrophosphate, or sodium tripolyphosphate) limit the mineralization of plaque, which will, in turn, prevent the growth of supragingival calculus.

Many tartar-control toothpastes use this process as the foundation of action. The theory proposes that, if the enamel surface remains calculus-free, the whitening effect is accomplished through the management of a clean enamel surface. Again, with this method, the natural shades of the teeth are unchanged. Some patients using this type of dentifrice may experience temperature sensitivity to toothpastes that have chemicals that are absorbed into the enamel or exposed dentin.

Peroxide lightening. The benefit of peroxide as an oxidation agent has been well-documented in dental literature. Toothpastes containing peroxide are marketed to have the same action as professional peroxide-containing whitening systems.

However, let`s reconsider the oxidation process. It occurs when oxygen combines with stain molecules in enamel and dentin to make organic stains more soluble. The resulting oxidation penetrates both enamel and dentin to remove organic material within the tubular structures and is dissolved into the saliva and oral environment. Carbamide peroxide and hydrogen peroxide are the most common active ingredients used in vital tooth whitening. Carbamide peroxide`s contact time in a whitening tray can range from two to four hours and hydrogen peroxide`s wear time is about 30 minutes.

Ask yourself when the last time was that one of your clients brushed his teeth for four hours. Additional challenges with these products are low concentrations (1 to 2 percent) of the peroxide and the immediate contamination of the toothpaste by bacteria and saliva.

Cosmetic masking. The last option for the dentifrice category is cosmetic masking. Cosmetic dentifrices mask extrinsic stains with chemical compounds such as titanium dioxide, which is a common ingredient in paint. The stains are not removed, but are theoretically covered with a lighter-colored material. The results of this option vary and are difficult to maintain.

Now you are probably asking how Crest Whitening obtained its ADA Seal of Acceptance. It was granted in 1999 under the Acceptance Program for Home-Use Tooth Whitening Products (a category initially established for OTC bleaching kits). Historically, dentifrices have been awarded the seal for caries prevention, prevention of plaque and gingivitis, and relief of dentinal hypersensitivity. However, the ADA Council on Dental Therapeutics has been under some fire lately by its members for granting such an approval. Some members have expressed a concern over the granting of the official stamp for "stain removal" vs. true whitening. They are troubled that the approval has created even more confusion among clients.

Abrasion on composites

The dentifrice story is further complicated by not just the effects on natural dentition, but also what effects dentifrices have on esthetic systems. A majority of the research in this area has been performed in vitro and with varying research modalities and testing conditions. However, analyzing the information may prove to have some clinical significance. Keep in mind that the ingredients for the "perfect dentifrice" for esthetic therapies have yet to be agreed upon. Most studies compare the rate of abrasive wear and change in surface roughness of composite restorations when subjected to toothbrush/dentifrice abrasion.

Some guidelines to consider when choosing a dentifrice for your cosmetic clients include:

Y A lower abrasion toothpaste or a lower percentage of abrasive particles (such as silica)

Y Products with neutral sodium fluoride

Y Basic pastes vs. multifacted gels

During your interactive examination, discuss the client`s frequency of brushing and technique. To ensure that the restorations are not being aggressively cared for, educate on brushing effectively, yet gently, three times a day with a low-abrasion tooth polish or paste. Overly aggressive toothpaste/toothbrush combinations may adversely affect the restoration`s longevity, so education about the combination of brush and paste is also vital. Other documentations that should be recorded in the client`s chart include the amount of toothpaste used each day, the length of time spent brushing, pressure used, any tooth sensitivity experienced, or gingival burning or sloughing present.

Provide clients with verbal and written instructions, as well as product recommendations. The client should be given a well-drafted and easy-to-follow guide as to where to get the recommended dentifrice (if not dispensed in the practice) and why the hygienist is recommending this particular product. Lastly, the practitioner needs to reinforce to the patient that the results are best maintained through professional supervision and excellent hygiene practices.

Esthetic procedures are most successful in a well-controlled environment, and this will provide clinicians the opportunity to educate that client on how optimal oral hygiene is key in maintaining esthetic results.

If clients choose to use a whitening dentifrice, remember to explain thoroughly the hypotheses behind whitening dentifrices. If the tooth surfaces remain plaque- and bacteria-free, the whitening effect is sustained through meticulous oral hygiene, not a special product.

References available upon request.

Kristine A. Hodsdon, RDH, BS presents seminars nationally about

esthetic hygiene. Her company, Dental Essence, is based in Chester, N.H. She can be e-mailed at