Osteonecrosis of the jaw, also known as “dead jaw,” refers to severe bone disease of the upper and lower jaw — called the maxilla and mandible, respectively. It was identified more than 150 years ago, and in 2003 was first described as a consequence of bisphosphonate therapy.

Scientists originally believed that it was caused only by intravenous, but not oral bisphosphonate therapy. Later research showed that oral dosing could also cause osteonecrosis of the jaw.

Understanding the mechanism of action of bisphosphonates should lead any doctor to predict such an illness. Bisphosphonates poison the osteoclasts — the cells in the bones that are responsible for removing old and injured bone.

Without osteoclastic functioning, the body has no mechanism to repair bones.

It does not take a medical degree to predict that poisoning a crucial step in bone metabolism may result in bone problems in the future.

That is exactly what can happen with long-term bisphosphonate use.