by Kevin D. Huff, DDS, MAGD
For more on this topic, go to www.dentaleconomics.com and search using the following key words: oral cancer, adjunctive screening technologies, chemiluminescence, Dr. Kevin Huff.
Adjunctive screening technologies can greatly assist in the oral cancer screening examination process, are excellent practice builders, and enhance the benevolent nature of the dental profession.
When used in conjunction with a conventional oral cancer screening exam, they offer a significant benefit to patients while also adding to practice profitability and practice growth. The addition of adjunctive oral cancer screening technologies to oral cancer physical screening exams has been reported in various studies to enhance general practitioners' abilities to detect subtle lesions in early stages of development.
Chemiluminescence was developed and initially marketed as ViziLite® (Zila Pharmaceuticals, Inc., Phoenix, Ariz.) and is now available as ViziLite® Plus. It has been FDA-approved for use in patients who are known to be at risk for oral cancer. A proprietary light source is used to “light up” white lesions by reflection and may make red lesions easier to see than by incandescence alone. Other manufacturers have adopted a similar basis for their products (Orascoptic DK™ and Microlux/DL™, both manufactured by AdDent, Inc., Danbury, Conn.).
They use a battery-powered LED visual light source rather than a chemiluminescent wand. In all of these systems, a diluted acetic acid is used as a prerinse to remove the glycoprotein barrier established by saliva and to dehydrate superficial mucosal cells to better visualize areas of increased nuclear activity. If a lesion is identified, a secondary marking agent such as TBlue630 may be used for photographic documentation. TBlue630, a commercially prepared stabilized vital dye is only available to ViziLite® users.
The ViziLite® Plus system unarguably has received the most press, and justifiably so. This was the first adjunctive visual aid available, and it is backed by the financial power of a major pharmaceutical company. Its major benefits are convenient single-patient packaging, established history of use, and the ability to use the TBlue630. However, the cost per patient is typically higher than the other systems, and an acetic acid prerinse is necessary.
The LED systems share the same benefits as ViziLite®, except that the TBlue630 is not available for its users through typical channels. Its initial cost is more and cost per patient is minimal because it uses a reusable light source, but the acetic acid prerinse is still necessary. Photodocumentation is difficult. The biggest obstacles with liquid-based systems are necessary chairtime and patient objection to the prerinse.
The VELscope® (LED Dental, Inc., Vancouver, B.C.) uses an entirely different technology based on the natural biofluorescent properties of cellular metabolites and collagen. Living cells have natural fluorophores that either absorb or generate light when stimulated by blue light (400-460 nm).
The fluorophores in the stroma and epithelium of oral mucosa absorb the blue excitation light and then re-emit light at a longer wavelength (green, yellow, or red) a fraction of a second later. A filtering system in conjunction with a blue light source is used to enable visualization of the green natural fluorescence of healthy tissues. No additional rinses or chemicals are necessary.
Rapidly reproducing cells, as in dysplasia, do exhibit less fluorescence than healthy cells due to a decrease in the fluorophore FAD+ and breakdown of the collagen matrix. The product has been cleared for use by the FDA as a safe screening tool as well as for use in surgical margin delineation. The VELscope® is helpful in identifying subtle erythroplakia, leukoplakia, mixed lesions, and inflammatory lesions. Although “off-label,” I have found this technology also helpful in identifying areas of chronic inflammation and areas of increased pressure from removable prostheses.
The newest version of the VELscope® is now being marketed as the Vantage, which has a more powerful light source than the original device. Although it is easy to use, the initial cost and maintenance fees are similar to dental operatory lights. Its greatest advantages are ease of use, relative ease of photodocumentation, and minimal cost per patient. It is the only visual screening aid with published effectiveness in a low-risk general dental practice, and the use of VELscope® as a surgical margin delineation tool for the management of dysplasia, BONJ, and carcinoma in situ has been well-published.
All of these tools, including the latest device — Identafi™ 3000 — are very new, so there are very few controlled clinical studies available. Those that are available report favorable conclusions for the use of adjunctive visual aids. Choosing “the right one” for each particular practice should be based on practice philosophy, fees, patient comfort, and proper continuing education.
Kevin D. Huff, DDS, MAGD, is a practicing general dentist in rural Ohio, a private researcher, author, and dental educator. A clinical instructor at the Case School of Dental Medicine, he lectures nationally about oral cancer screening and biopsy techniques. Contact him at [email protected], or visit www.doctorhuff.net.
