Dental endosseous implants in patients on bisphosphonate therapy

About a decade ago, bisphosphonates were introduced as an alternative to hormone replacement therapies for osteoporosis and to treat osteolytic tumors. More recently, it has became evident that the bisphosphonates used intravenously such as pamidronate (Aredia; Novartis Pharmaceuticals Corp., East Hanover, NJ) and zoledronate (Zometa; Novartis Pharmaceuticals Corp.), in particular, could lead to painful refractory bone exposure (sometimes termed osteochemonecrosis or osteonecrosis) in the jaws. Patients with osteonecrosis of the jaws usually present after dental treatment with oral signs and symptoms of painful, exposed, and necrotic bone, primarily of the mandible and, to a lesser extent, the maxilla. Although the precipitating event that produces this complication may be spontaneous, there is little doubt that oral surgery and endosseous implants can be responsible. Exodontia is the main precipitant. The present postulated mechanism of osteonecrosis of the jaws is that prolonged use of bisphosphonates may suppress bone turnover to the point that the repair function of physiologic microdamage of bone is abolished. Such a mechanism could presumably interfere with the healing process after implant placement. Although, to our knowledge, there is no evidence that bone disorders are a contraindication to implants, there is evidence that bisphosphonate therapy is a contraindication. Where possible, extractions should be avoided, and it is best to avoid all elective oral surgery in patients on bisphosphonates, including endosseous implant placement, or the treatment should be performed well before commencing bisphosphonates. If surgery is essential on a patient taking bisphosphonate therapy, the patient must be counseled about the risks.