Enhancing the Efficiency and Efficacy of In-Office Whitening Using a Chairside Lamp

Despite the availability of many over-the-counter tooth-whitening products and a variety of clinician-dispensed take-home whitening treatments, the demand for in-office tooth whitening continues to gain momentum.¹ Fast, effective, and now more comfortable for patients than earlier options, today’s in-office whitening treatments provide clinicians with opportunities to enhance patients’ smiles in a minimally invasive way. According to recent statistics, these opportunities are likely to increase.

In a recent survey of Americans conducted by the American Academy of Cosmetic Dentistry (AACD),² whiteness and tooth color were among the top smile features that respondents said they notice in a person’s smile; discolored, yellow, or stained teeth were cited the most as the characteristics that make a smile unattractive. Not surprisingly, when asked what they would most like to do to improve their smile, respondents said whiten and brighten their teeth.

Tooth Color and Stains

Affecting the whiteness and brightness of a person’s smile is tooth color, which refers to the inherent color of a tooth as perceived by others.³ Tooth color is affected by the color tone of dentin, transparency of enamel, and imbedded stains on the dentin and enamel. Tooth staining could result from poor oral hygiene, dietary considerations, tobacco and medication use, and medical history and aging.

The two classifications of tooth stains—intrinsic and extrinsic—are determined by the location of the stains in relation to the enamel. Intrinsic stains are beneath the enamel’s surface and result from age, tooth trauma, and certain medications. Over time, chromagenic materials diffuse into the enamel and accumulate at the dentin level and within the enamel. Generally, the only way to eliminate these stains is through whitening procedures.

Extrinsic stains are found within the tooth pellicle and result from consuming stain-causing foods and beverages, tobacco use, and/or poor oral hygiene. Most can be easily removed by tooth brushing and using a whitening paste.

Among the subjective and objective tools available to determine tooth color—and by which changes in tooth shade from whitening can be measured—are the VITA Classical Shade Guide (Vident, www.vident.com) (for color-matching restorations); the VITA Bleached Shade Guide (Vident) (for assessing the efficacy of whitening); and spectrophotometry (eg, VITA Easy Shade [Vident]), a digital method for objectively assessing color change.³ The two shade guide methods are influenced by observer experience, external light, and the observer’s physiological condition. The spectrophotometry method is independent of lighting conditions and user influence.

When comparing tooth shades, a Delta E value, which is a unit of measure that calculates and quantifies the difference between two colors, is used. On a scale from 0 to > 6, the Delta E value is defined as a decrease in b (ie, yellowness), decrease in a (ie, redness), and increase in L (ie, lightness). The higher the Delta E value is, the greater the color difference.

Today, an in-office whitening system that combines the use of a chairside light-emitting diode (LED) light technology with the application of a hydrogen peroxide whitening gel enables teeth whitening of up to eight shades in 45 minutes (ie, three 15-minute gel applications) (Zoom WhiteSpeed, Philips Oral Healthcare, www.philipsoralhealthcare.com) (Figure 1).⁴ Additionally, by varying the light intensity based on patient characteristics (ie, sensitivity, whitening goals) and using a dentifrice containing potassium nitrate and fluoride, patients can undergo a more comfortable and effective whitening procedure with reduced sensitivity.⁵

Science of Light-Accelerated In-Office Whitening

When light shines on an object, some colors reflect off the object and others are absorbed by it; human eyes only see the colors that are reflected.⁶ On a color wheel, complementary colors are those on the opposite side, and they absorb the opposite color’s light most strongly (eg, magenta absorbs green; green absorbs magenta; blue absorbs yellow; yellow absorbs blue).

Yellow stain molecules are composed of two parts: the “body” of the molecule and the chromophore, which is the part that gives tooth stains their yellow color. When the electrons in stain molecules are excited, less energy is required to break the bonds they create. Blue light is readily absorbed by the electrons in the double carbon bond in the chromophore and excited by the light photons.

During an in-office light-enhanced whitening treatment, yellow stains in the dentin absorb the blue light produced by an LED chairside whitening lamp (eg, Zoom WhiteSpeed). Absorption of this light—which has a wavelength emission of 460 nanometers (nm) and the intensity of which can be set at three different levels—adds energy to the chemical reaction between the double carbon bond in the stains and the hydroxyl radicals produced through the breakdown of the hydrogen peroxide bleaching agent.

The excited electrons are more likely to interact with peroxide radicals (*OH) from the hydrogen peroxide gels, changing the double (C=C) bonds into single (C-C) bonds. Breaking the 4 C=C bond renders the molecule colorless. As a result, the in-office whitening treatment is more effective at breaking down and eliminating stains within the dentin.

In a recent study conducted by the University of Texas, an in-office whitening treatment, combining a chairside light-activated whitening system and hydrogen peroxide whitening gel produced considerably higher whitening dependent color changes in subjects receiving that treatment compared to those who only received hydrogen peroxide.⁷ These findings were significant in both tooth-whitening and color changes, proving the application of direct heat by a light source accelerates the oxidation process, producing faster and more esthetically pleasing results.⁷

Similarly, a comparative randomized panel study conducted at Loma Linda University assessed the whitening effect of two professional bleaching regimens.⁸ The study’s findings determined that the LED light-accelerated in-office treatment clinically outperformed the other in-office whitening, which contained 40% hydrogen peroxide, by 55% over 7-day and 30-day periods. The results also indicated that patients receiving the accelerated whitening treatment (ie, Zoom Whitespeed) along with amorphous calcium phosphate (ACP) experienced little to no sensitivity, pain, or discomfort.

Other research conducted over the past few years also confirms the efficacy and efficiency of in-office whitening treatments that combine hydrogen peroxide gel and chairside light acceleration.^9,10 Greater color changes have been observed with light acceleration than without, and the color changes in the yellow-blue dimension (ie, Delta L and Delta B) were not correlated with hydrogen peroxide levels.⁹

Further, when light sources have been specifically studied, photoactivation or acceleration of hydrogen peroxide whitening gel using an LED light was found to be the best choice. The whitening protocol studied produced statistically significant differences in color change compared to whitening treatments without light activation.^5,11

Conclusion

Zoom Whitespeed has been clinically shown to provide better whitening results than whitening with hydrogen peroxide alone. Results were significantly better immediate post, 7- and 30-day post treatment. Zoom Whitespeed has been clinically shown to whiten teeth up to eight shades in 45 minutes. After the initial recommended oral examination, the complete procedure takes one office visit and begins with a preparation period, followed by three 15-minute bleaching sessions, with an optional fourth 15-minute session to be dispensed at the dentist’s discretion.

To help reduce sensitivity, the in-office whitening lamp is equipped with three intensity settings (high, medium, and low) that can be changed to accommodate patient/case types and ensure a more comfortable treatment. Additionally, incorporating Relief^® ACP (Philips Oral Healthcare) provides highly effective protection against sensitivity for patients suffering from tooth sensitivity caused by gum recession, root exposure, post root planing, and whitening.

Without question, esthetic tooth whitening remains a popular and minimally invasive cosmetic procedure. An in-office whitening system that accelerates the active hydrogen peroxide whitening gel using blue LED light (Zoom Whitespeed) enables dentists to satisfy the growing demand for whiter and more vibrant smiles with greater efficiency and efficacy, and less sensitivity.

DISCLOSURE

Dr. Radz is a consultant for Discus Dental, which is a part of Philips Oral Healthcare.

ABOUT THE AUTHOR

Gary M. Radz, DDS
Associate Clinical Professor, University of Colorado School of Dentistry, Denver, Colorado; Private Practice, Denver, Colorado

REFERENCES

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