Deja Vu: Phossy Jaw

Q: How does phosphorus cause ‘Phossy Jaw’?



A: So, ‘phossy jaw’ is essentially a form of osteonecrosis of the jaw bone. It predominantly affects the lower jaw and was seen first in matchstick factory workers in the 19th century, as they were exposed to high amounts of white phosphorus.

To understand the pathophysiology of phossy jaw, we must know how bone is maintained in our body.



Bone matrix is synthesized by specialised cells called osteoblasts and remodelled (destroyed to make better bone) by osteoclasts.


Both osteoblasts and osteoclasts are vital for maintenance of bone mass, especially after bone injury for proper healing!

Now what one must know is that the function of osteoclasts is affected by a number of factors, and one class of compounds that inhibit their activity is bisphosphonates.

White phosphorus, with water, oxygen and an acidic environment in the presence of organic amino acids like lysine, gets converted to potent bisphosphonates. [1]



So when the bone is injured by trauma, tooth extraction or even daily wear or tear, osteoclasts are essential for the bone remodelling process, which is inhibited by bisphosphonates.[1]

Also, bisphosphonates prevent angiogenesis (development of new blood vessels) that impairs formation of new bone in these patients! [2]

This disease that was seen is matchstick factory workers is called BONJ (Bisphosphonate associated osteonecrosis of jaw) and was fully understood 200 years later after the disease was rediscovered in patients taking bisphosphonates as a therapy for osteoporosis!
(as bisphosphonates inhibit osteoclast activity, this effect is desirable in patients with low bone mass)

Hence as new bones is not formed and remodelling isn’t done adequately, the jaw becomes severely deformed and painful. History repeated itself when these patients had the same features as those who had occupational exposure to phosphorus at matchstick factories; hence some call this the second epidemic of the disease!

Nowadays, regulations mandate jaw protection and scrupulous dental hygiene for workers exposed to white phosphorous!

By Dr Ashwin Mahesh

References:


[1] Uncovering the cause of "phossy jaw" Circa 1858 to 1906: oral and maxillofacial surgery closed case files-case closed.Marx RE. J Oral Maxillofac Surg. 2008.
J Oral Maxillofac Surg. 2008 Nov;66(11):2356-63. doi: 10.1016/j.joms.2007.11.006.
[2] Bisphosphonates Cause Osteonecrosis of the Jaw-Like Disease in Mice.Yanming Bi, Yamei Gao, and Li Zhang
Am J Pathol. 2010 Jul; 177(1): 280–290. doi:  10.2353/ajpath.2010.090592 PMCID: PMC2893671 PMID: 20472893
[3] Bamias A, Kastritis E, Bamia C, Moulopoulos LA, Melakopoulos I, Bozas G, Koutsoukou V, Gika D, Anagnostopoulos A, Papadimitriou C, Terpos E, Dimopoulos MA. Osteonecrosis of the jaw in cancer after treatment with bisphosphonates: incidence and risk factors. J Clin Oncol. 2005;23:8580–8587. [PubMed]

[4] Ruggiero SL, Woo SB. Bisphosphonate-related osteonecrosis of the jaws. Dent Clin North Am. 2008;52:111–128. [PubMed]

[5] Kuehn BM. Reports of adverse events from bone drugs prompt caution. JAMA. 2006;295:2833–2836. [PubMed]

[6] Woo SB, Hellstein JW, Kalmar JR. Systematic review: bisphosphonates and osteonecrosis of the jaws. Ann Intern Med. 2006;144:753–761. [PubMed]

[7] Khosla S, Burr D, Cauley J, Dempster DW, Ebeling PR, Felsenberg D, Gagel RF, Gilsanz V, Guise T, Koka S, McCauley LK, McGowan J, McKee MD, Mohla S, Pendrys DG, Raisz LG, Ruggiero SL, Shafer DM, Shum L, Silverman SL, Van Poznak CH, Watts N, Woo SB, Shane E. Bisphosphonate-associated osteonecrosis of the jaw: report

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