Bisphosphonates are a class of drugs that inhibits bone re-modeling (inhibit osteoclast activity). They are the essential component of most osteoporosis medications and intravenous drugs used to treat cancer. Concern has arisen because in rare cases, the bisphosphonates can result in severe bone necrosis after certain dental procedures.
Necrosis is when the bone dies and sloughs away due to a lack of blood supply. Osteonecrosis refers to sloughing of the bone. Theoretically, the inhibitory effect of the bisphosphonates on the osteoclast cells doesn’t allow the jawbone to re-model. Without the capacity to re-model, the surface layer of the jawbone loses its blood supply and dies away.
Osteonecrosis from bisphosphonates only primarily occurs after exposure of the jawbone to the outside environment. In other words, unless the jawbone is exposed, such as after tooth extractions or periodontal flap surgery, there is extremely minimal risk to experiencing bone necrosis. Undergoing root canal procedures, fillings, or crowns do not expose the underlying bone and thus are safe (however medical clearance is still needed prior to treatment).
Even after procedures where the jawbone is exposed, the risk of osteonecrosis is extremely rare. Research is beginning to show that patients taking oral bisphosphonates, like those used to treat osteoporosis, are safe to proceed with surgical procedures. It is the IV form of bisphosphonates that creates a greater concern and may be a contraindication to oral/periodontal surgery.
In any event, consultation and clearance from the physician is mandatory prior to proceeding with treatment. In addition, consent forms must be signed allowing the dental practitioner to proceed.
Overall, it is important to be aware of the risks associated with bisphosphonate medication; however, oral bisphosphonates are not an absolute contraindication to receiving dental treatment.