Osteoporosis, Bisphosphonates and Dental Implants

I have heard a lot of questions asked by dental professionals as well as patients regarding these topics lately.  The underlying question usually was: Do they mix?

Osteoporosis is a common disease characterized by decreased bone mass, increased bone turnover, and increased susceptibility to fracture.  In general, Osteoporosis itself is NOT a contraindication to having dental implants done.  Studies have shown that patients with osteoporosis enjoy the same kind of success rates with dental implants as patients without osteoporosis do.  What CAN present itself as a potential risk factor to dental implant surgery (and any kind of oral surgery for that matter), however, is the administration of Bisphosphonates (such as FOSAMAX®), which are designed to counteract the effects of osteoporosis.

Bisphosphonates belong to a class of drugs which inhibit osteoclast action and thus the resorption of bone.  This works well for maintaining good bone density (since the resorption cycle is being interrupted), however it can have disastrous consequences following bone surgery.  Bone will undergo a very structured healing response after surgery, which includes remodelling and turnover.  Osteoclasts play a very important part in this remodelling cycle of the healing phase.  If the osteoclast action is interrupted, osteonecrosis (bone cell death) may be a consequence.

Now not every regiment of bisphosphonates is a significant risk factor for post surgical osteonecrosis.  Up until very recently we have only haphazardly determined that injectable regiments of bisphosphonates or regiments of oral bisphosphonates for over three years present a definite contraindication to dental implant surgery.  Recently however, a test became available, which gives us a much more accurate way of determining the risk factor:  The CTx Test.

The CTx test, also known as the serum C-terminal telopeptide test, is a medical blood test that is used to assess the risk of bisphosphonate-induced osteonecrosis of the jaws.  C-terminal telopeptide is a marker used to measure bone metabolism. It is a by-product of normal bone metabolism or bone turnover.  If the CTx test shows a low value of CTx, then the implication could be that the bone turnover is low, thus the bone is less likely to recover from trauma, such as a tooth extraction or implant placement.  According to Marx ( J Oral Maxillofac Surg. 2007 Dec;65(12):2397-410.): “A stratification of relative risk was seen as CTX values less than 100 pg/mL representing high risk, CTX values between 100 pg/mL and 150 pg/mL representing moderate risk, and CTX values above 150 pg/mL representing minimal risk. The CTX values were noted to increase between 25.9 pg/mL to 26.4 pg/mL for each month of a drug holiday indicating a recovery of bone remodeling and a guideline as to when oral surgical procedures can be accomplished with the least risk.”   The latter portion of Marx’s statement implicates that any kind of Oral Surgery (including dental implant placement) could be an option, if a patient is taken off the regiment (under careful observation of his or her physician, of course) for about 3 months and a CTx re-test is taken for verification of new values.

If necessary, your dental professional or physician can order this test for you.  This test should be taken after 12 hours of fasting.