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Post-menopausal women constitute a significant subset of the patient population seeking toreplace removable partial or ful dentures with implant-supported restorations. This populationmay also be taking one of several available drugs to prevent or treat osteoporosis. Oralbisphosphonate therapy inhibits osteoclastic activity, and thus patients who are taking such drugsmay be at risk for developing bisphosphonate-induced osteonecrosis of the jaw (BIONJ) fol owingexposure of the bone during tooth extractions or placement of dental implants. For that reason,some authorities have suggested that osteoporotic women receiving oral bisphosphonate therapymay not be good implant candidates.
Robert E. Marx, DDSProfessor of Surgery & Chief However, today the risks associated with bisphosphonates can be managed, and dental implants can be placed with little or no risk of BIONJ. Among the three most commonly prescribed oral bisphosphonates – Actonel® (risedronate sodium), Boniva® (ibandronate sodium), and Fosamax® (alendronate) -- Fosamax is the only one of major concern. Fosamax is given at twice the dose of the other two drugs, and it has been associated with a greater incidence of BIONJ. Amongpatients tracked in our database, Fosamax usage has accounted for 97% of such cases.
Implant candidates who are taking either Actonel or Boniva thus can be treated essential y likeany other patient receiving implant therapy. For those taking Fosamax, the length of time on thedrug is a critical consideration. Those who have taken it for two years or less appear to havenormal bone healing, compatible with osseointegration. Taking Fosamax for more than two years,however, does appear to significantly increase the risk of impaired alveolar bone healing. Fosamaxaffects mature osteoclasts as wel as the osteoclastic precursors in the bone marrow. It usual ytakes two or more years of drug usage for the number of mature osteoclasts to be reducedenough to affect osseointegration significantly, and if the patient continues taking Fosamax, a slowor impaired recovery of bone-marrow precursors wil continue to threaten osseointegration.
What should clinicians do when presented with patients who desire dental implant therapy buthave been taking Fosamax for several years? A first option is to have the patient tested for theserum marker C-terminal telopeptide (CTX). A by-product of normal bone turnover, this peptidesequence is the portion cleaved by osteoclasts during bone resorption. Serum levels of it are thusproportional to osteoclastic activity at the time the blood sample was drawn. A CTX level ofmore than 150 picograms per mil iliter is a good indication that the patient’s alveolar bone wilheal normal y fol owing implant surgery and that the implants wil successful y osseointegrate.
If ordering the test is not feasible, an alternative is for the patient to discontinue taking Fosamax,at least temporarily. Obviously, this should only be done with the approval of the patient’sphysician. However, most physicians are comfortable agreeing to such “drug holidays.” The effectsof bisphosphonate therapy are long-lasting; the drugs’ half life is 11 years. Reliable research hasshown that patients who have taken bisphosphonates for three to five years can stop using thesedrugs for up to five years without causing any change in osteoporotic status. Indeed, the US Foodand Drug Administration has recently recommended that bisphosphonate drug companiesimprove their product descriptions to suggest limiting the duration of use.
As in all aspects of implant dentistry, the underlying biology must be respected. For patientsreceiving bisphosphonate therapy, the underlying biological processes create a window ofopportunity. Clinicians must be wil ing to communicate with their physician col eagues in orderto organize drug holidays for osteoporotic patients. Those who do so can enable those patientsto get the therapy they want while protecting them both from osteoporosis as wel as from therisk of BIONJ.
JOURNAL OF IMPLANT AND RECONSTRUCTIVE DENTISTRY® 2011 Vol. 3 No. 1

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