The Return of the ... Dreaded ‘Phossy Jaw’
July 27, 2009
by Lynne Slim, RDH, BSDH, MSDH
During the early 19th century, it was discovered that adding yellow (now called white) phosphorous to matchstick heads made it easier to ignite matches. As a result, there was an enormous demand for these “strike-anywhere” matches. During the industrial revolution, this new industry of matchmaking was profitable, and low wage workers spent 10 to 15 hours a day over large heated vats that contained yellow phosphorus.
The phosphorous vapors were breathed in by workers and combined with other chemicals in the body to produce a potent nitrogen-containing bisphosphonate. Today’s oral nitrogen-containing bisphosphonates and intravenous nitrogen-containing bisphosphonates circulate around the body the same way as the phosphorous vapors, and are absorbed into bone and ingested by osteoclasts. When this unique binding process of bisphosphonates to bone occurs, osteoclasts are poisoned, and this reduces or eliminates bone turnover. Alveolar bone in the mandible and maxilla turns over more rapidly than in long bones, so the jaws are a better target for bisphosphonate toxicity.
The first case of “phossy jaw” was recorded in 1838, and the victim, a female Viennese matchstick maker, had been exposed to the phosphorous vapors over a five-year period. Back then, the average time between exposure to the phosphorous vapors and the appearance of “phossy jaw” was about five years, but only about 5% of those exposed were inflicted with this disfiguring and often lethal affliction....
Epidemiology of BIONJ
It wasn’t until 2003 that today’s intravenous and oral nitrogen-containing bisphosphonate medications were implicated as major risk factors in the development of exposed necrotic bone of the jaws. Since then, a literature review of case reports from around the world has been published and a summary of epidemiological data surrounding these cases has been reported.
Most of the researchers who reported cases of bisphosphonate-induced osteonecrosis of the jaw (BIONJ) found that these patients were treated with zoledronate, pamidronate, or a combination of these drugs, which are commonly used for treating breast cancer or myeloma. In about 5% of cases, subjects with BIONJ were being treated for osteoporosis. Precipitating events that contribute to BIONJ are tooth extractions (about 50% of cases), mandibular exostoses, periodontal disease, and local trauma from ill-fitting dentures. It is not known if the placement of dental implants is a precipitating factor, and a recent study implicates smoking and obesity as possible risk factors. It is also common for BIONJ subjects to be taking cytotoxic drugs and glucocorticoids....
Osteoporosis and oral nitrogen-containing bisphosphonates
BIONJ is also associated with the oral administration of nitrogen-containing bisphosphonates to treat osteoporosis. To date, epidemiological evidence linking BIONJ to oncology patients treated with intravenous bisphosphonates is stronger and more reliable than data surrounding oral bisphosphonate use. In the risedronate (Actonel®) and alendronate (Fosamax®) clinical trials of 16,000 to 17,000 patients, no cases of BIONJ were reported, but post-marketing surveys conducted to mid-2007 indicated an incidence of <1.2 per 100,000 patient-years for risedronate and <0.5 to 2.5 per 100,000 patient-years for alendronate. To date, the prevalence of BIONJ associated with oral bisphosphonates is approximately one per 100,000 patient-years, and it has been reported that this is not too different from that reported in the general population. The number of patients taking bisphosphonates for osteoporosis and other metabolic bone diseases such as Paget’s disease is much greater than patients with cancer. Therefore, even a low incidence of oral-induced BIONJ may be significant....
A couple of studies reported higher risk of BIONJ associated with oral bisphosphonates, and the first one was in Australia, where oral surgeons identified cases prospectively. The percentage of patients with BIONJ (who had taken an oral bisphosphonate) was five- to tenfold greater than reported in other case studies to date. In a recent U.S. large institutional study, researchers identified 208 patients with a history of alendronate use. Nine out of 208 had active BIONJ and were being treated in the institution’s dental clinic. Approximately one in 23 of these patients were receiving alendronate (which equals about 4% of the population).
[Read full article at original source. Footnotes and table references omitted.]