Bisphosphonates are a multibillion dollar class of bone wonder drugs with more than 10 million users world-wide. The drugs are used both to combat the ravages of osteoporosis as well as to certain forms of cancer. Familiar brand names would include Actonel, Aredia, Boniva, Fosamax, Skelid and Zometa. Red warning flags went up in recent years when news began to surface tying the use of bisphosphonates to bone infections, ‘osteonecrosis’ especially in the jaws.
At a recent seminar Dr. Douglas Damm, an Oral Pathologist from the University of Kentucky College of Dentistry shared some of the latest findings. Bone is made up of three types of cells. The basic body of a bone is made up of cells called ‘osteocytes’. In addition there are two other specialized types of bone cells. ‘Osteoclasts’ break down and carry away osteocytes that have died after their normal three month life cycle. And ‘osteoblasts’ create new osteocytes to replace those that have died.
Bisphosphonate drugs quickly identify parts of the body in which osteoclastic activity is at a peak and concentrate in those areas. Bone loss is slowed almost immediately for patients who are suffering from osteoporosis or certain types of bone cancer. The bad thing is that when osteocytes die as they always do after about three months, there is no longer osteoclast activity to break down and remove the dead cells. In time sections of bone in areas where the bisphosphonate drugs have been most active literally die. On the surface that might seem like a problem but in actual fact the dead bone can be very dense, quite strong and nicely tolerated. Where we get into trouble is when bacteria somehow gain access to the dead patches of bone. Where might that happen with some degree of regularity? The jaws of course!
If a patient who is taking bisphosphonate drugs has oral inflammation associated with gum or tooth disease it is likely that the bisphosphonates will concentrate in and around those areas in response to the inflammation. Osteoclastic activity is inhibited and in time sections of dead bone exist in and around the jaws. The patient has a tooth removed or a dental implant placed or a root canal procedure, bacteria gain access to the bone and a rampant uncontrollable infection of the bone, osteonecrosis, is born!
In the early days there were some random guidelines established regarding dental work with patients utilizing bisphosphonate drugs. Today those guidelines have been modified and improved based on a better understanding of what is happening in these cases. So what does this mean for you or your loved ones who are taking bisphosphonates? First, it does not mean that people should stop taking their bisphosphonate drugs. What it does mean is that your dental team MUST know that you are using these products so that they can safely provide guidance for you in the event that the need arises for you to have invasive dental surgery. The guidelines involve a brief drug vacation which eventually allows for the osteoclasts to get back to work in these areas where bone has died. We can work around most of these situations when we all communicate and understand the full picture.
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