| Doug Kase, D.D.S.
Tales from the Chamber
Something New to Consider! |
Doug Kase
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ALL KNOW the importance of taking a proper medical history before initiating
any diagnosis and ultimate treatment plan. Since we are all familiar
with the standard questions on standard medical history forms, particularly
patients’ current medications, I will get right into the meat and potatoes
of my article.
As I have been treating more and more patients whose extensive or
not-so-extensive lists of pharmaceuticals now include medications to treat
or prevent osteoporosis, a new question seems to be popping up, not only
in the research literature, but also right out of the patients’ mouths.
Patients are now asking about a condition that would send shivers up and
down a dentist’s spine, osteonecrosis of the jaw and its association with
osteoporosis medications. This pathology, which mimics osteomyelitis,
is one we commonly associate either with a severe bacteriological source
or as a post-operative symptom of a combination of oral surgery and radiation
therapy to the jaw (osteoradionecrosis of the jaw). Now this condition
seems to be related to the class of osteoporosis medications called bisphosphonates.
According to the ADA,
reports of bisphosphonate-associated osteonecrosis of the jaw
(BON) associated with the use of Zometa (zolendronic acid) and Aredia (pamidronate)
began to surface in 2003.” The majority of reported cases have been
associated with dental procedures such as tooth extraction; however, less
commonly BON appears to occur spontaneously in patients taking these drugs.
Zolendronic acid and pamidronate are intravenous (i.v.) bisphosphonates
used to reduce bone pain, hypercalcemia, and skeletal complications in
patients with multiple myeloma, breast cancer, lung cancer, and other cancers,
and Paget’s disease of bone. Several cases of BON have also been
associated with the use of the oral bisphosphonates Fosamax (alendronate),
Actonel (risedronate), and Boniva (ibandronate), for the treatment of osteoporosis;
however, it is not clear if these patients had other conditions that would
put them at risk for developing BON.
The medication list in the table on this page is
available on the ADA web site.
Symptoms of osteonecrosis of the jaw can mimic
other common pathologies associated with simpler sources, such as periodontal
disease or an endodontically involved tooth. Pain, soft tissue swelling,
loose teeth, suppuration and drainage, and exposed bone are common symptoms
of this condition. Patients may also have numbness, a feeling of
heaviness, or both. They may even remain asymptomatic for a period
of time. How the bisphosphonates cause the disease is still an open
question. The theory is that this class of medication inhibits new
vessel formation; thus it interferes with new bone formation. Again, according
to the ADA, “Bisphosphonates inhibit osteoclast differentiation, and induce
osteoclast apoptosis resulting in an imbalance in the bone remodeling process.
They, thereby, promote an increase in bone trabecular thickness and bone
mass. Bisphosphonates may carry the potential for severe suppression of
bone turnover that may impair some of the biomechanical and reparative
properties of bone.” Even though invasive oral surgical procedures
are a possible cause in some cases, there are also suggestions that bone
may be involved independently. The risk factors for BON have not been identified;
however, the bone antiresorptive potency of the drug utilized may play
an important role. Remember that since less of the drug is absorbed
by the body (1 percent) when taken orally, there is less available to incorporate
into bone than when administered via iv (>50 percent availability).
This difference in availability may be the reason why there is a higher
incidence with the iv administered bisphosphonates. Additionally, their
presence in bone for many months after discontinuation of the medication
may place unrealistic time constraints on proper dental treatment.
In some cases in which iv bisphosphonates were used it is recommended to
treat patients as if they had had radiation therapy to the jaw (perform
no extractions and endodontically treat anything you can).
OK, what does all this mumbo jumbo finally
come down to? Although the incidence of these cases is low, the fact
that they exist means that we have to consider this in our diagnosis and
treatment planning and informed consent. Please continue to consult
the ADA web site for recommendations and updates regarding this topic.
November - December 2006
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© Copyright 2006 by Musikant, Deutsch,
Kase, Dukoff, Bui, & Hoffman. All rights reserved.
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