JCDA - Canadian Dental Association

Point of Care
The Point of Care section of JCDA answers everyday clinical questions by providing practical information that aims to be useful
at the point of patient care. The responses reflect the opinions of the contributors and do not purport to set forth standards of
care or clinical practice guidelines. Readers are encouraged to do more reading on the topics covered. This month’s responses were
provided by Dr. Paul C. Edwards, a resident in the division of oral and maxillofacial pathology, department of dental medicine,
Long Island Jewish Medical Center. If you would like to submit or answer a question, contact editor-in-chief Dr. John O’Keefe at
jokeefe@cda-adc.ca.
Question 1
Several screening tools are now available
in Canada to assist in evaluating
intraoral epithelial lesions.
Orascan (Zila Professional
Pharmaceuticals, Phoenix, Arizona;
distributed by Patterson Dental Supply)
is a mouth rinse containing toluidine
blue (tolonium chloride), which selectively
binds to free anionic groups such
as the phosphate groups of DNA. In
vivo, toluidine blue reportedly stains
malignant epithelial lesions a blue
colour. Orascan is recommended by the
manufacturer for monitoring of suspicious
lesions for which there has been a
baseline histopathologic evaluation,
screening for the presence of cancerous
lesions in high-risk individuals, routine follow-up of
patients previously treated for cancer of the upper aerodigestive
tract and determination of the optimal site for
biopsy of large, heterogeneous lesions.
Areas of inflammation, irritation and ulceration, as well
as the dorsum of the tongue (an uncommon site for
squamous cell carcinoma), routinely pick up the dye.
When used for screening in populations with a low
prevalence of squamous cell carcinoma, the sensitivity and
specificity appear lower than when used in high-risk populations.
1 Therefore, in the absence of clinically suspicious
areas in low-risk patients, areas that stain should be retested
after 10 to 14 days, during which time any transient
inflammatory lesions can be expected to heal.
Orascan is not a diagnostic test, and the absence of
staining does not rule out cancerous lesions or preclude the
need for a scalpel biopsy if the clinical presentation
warrants. The Canadian Academy of Oral Pathology has
recommended that “lesions suspected clinically of being
malignant or premalignant should be investigated by
Journal of the Canadian Dental Association
What are the indications for using diagnostic aids such as Orascan, Oral CDx and Vizilite in
the evaluation of oral lesions?
Figure 1: Patient with unilateral
erythroleukoplakic lesion of the right
buccal mucosa. Although tissue biopsy
results were consistent with lichen planus,
long-term follow-up with one of the screening
tools described, coupled with periodic
scalpel biopsy, would be appropriate.
Photograph courtesy of Dr. John Fantasia.
Figure 2: Patient with unilateral
erythroleukoplakic lesion of the left buccal
mucosa. Although there was clinical
suspicion for carcinoma, the tissue biopsy
was interpreted as nonspecific mucositis,
and long-term follow-up with one of the
screening tools would be appropriate.
Photograph courtesy of Dr. John Fantasia.
prompt incisional biopsy regardless of staining reaction to
toluidine blue.” 2
Oral CDx (Oralscan Laboratories, Suffern, N.Y.;
distributed by Henry Schein Dental) is a computer-assisted
brush biopsy analysis system. The dentist uses a brush
biopsy instrument to obtain cells from all layers of the
epithelium. The sample is evaluated to verify adequate
representation of the basal layer. Individual cells are examined
for a combination of abnormal morphology and spectral
abnormalities of keratin that are characteristic of
altered epithelial differentiation. Approximately 200 of the
highest scoring (most abnormal) cells are selected by the
computer for analysis by a cytopathologist.
Oral CDx is not a substitute for traditional scalpel
biopsy because the tissue obtained is disaggregated and
does not contain the necessary architectural information
to histologically assess and grade dysplastic lesions. 3
According to the manufacturer, Oral CDx facilitates the
testing of apparently innocuous epithelial lesions with no
obvious cause that are not sufficiently suspicious-looking to
November 2003, Vol. 69, No. 10 677