Letter to the Editor: Re: "Implant Placement With or Without Simultaneous Tooth Extraction in Patients Taking Oral Bisphosphonates: Postoperative Healing, Early Follow-Up, and the Incidence of Complications in Two Private Practices".

Abstract

To the Editor: Re: Implant Placement With or Without Simultaneous Tooth Extraction in Patients Taking Oral Bisphosphonates: Postoperative Healing, Early Follow-Up, and the Incidence of Complications in Two Private Practices. Fugazzotto PA, Lightfoot WS, Jaffin R, Kumar A. (J Periodontol 2007;78:1664-1669). Recently, Fugazzotto et al. reported the results of a study showing that a history of oral bisphosphonate use was not found to be a contributing factor to the development of osteonecrosis of the jaw (ONJ) following implant placement in edentulous ridges or tooth extraction with immediate implant placement.1 This conclusion was based on two practice-based patient populations including 61 patients. No osteonecrosis was noted immediately postoperatively or during the follow-up period that lasted an average of 3.3 years. We find the conclusion of this study challenging because we see two major discrepancies between the study design and the results. If left unnoticed or misinterpreted, these discrepancies might give the reader the wrong impression about the safety of implant placement in patients administered oral bisphosphonates. First, the mean duration period of oral bisphosphonates described in this study is too short relative to the information available in the literature2 about the average onset of ONJ in patients administered oral bisphosphonates. In a recent study2 describing a group of 11 patients diagnosed with oral bisphosphonate–related ONJ, the mean duration of alendronate use before developing ONJ was 4.1 years. In the present study, only 26 of the 61 subjects used oral bisphosphonates ≥4 years before implant placement. Moreover, only four of these subjects used 70 mg alendronate per week, which is the standard regimen for osteoporosis; the remaining 22 subjects used only 35 mg alendronate per week. Since the accumulating doses of bisphosphonates probably play a major role in the occurrence of ONJ, the risk for osteonecrosis in these 22 patients may be even lower than was reported in patients using the standard regimen. Second, according to the data provided by the manufacturer of the most prescribed oral bisphosphonate,∗ the estimated incidence of ONJ in their records is 0.7 cases per 100,000 person-years of exposure.3 Based on our patient population, we suspected that the estimated incidence in Israel may reach one case of osteonecrosis per 4,000 patients administered oral bisphosphonates.2 Since this article2 was submitted, at least six additional patients were diagnosed with oral bisphosphonate–related osteonecrosis at our clinics, which indicates an even higher incidence in Israel. Mavrokokki et al.4 reported the frequency of ONJ in osteoporotic patients, mainly on a weekly oral alendronate protocol, to be one in 2,260 to 8,470 patients. In this study based on Australian data, if extractions were carried out, their calculated frequency was one in 296 to 1,130 cases. Even if the incidence of ONJ after dento-alveolar surgery is as high as the Australian data, a study including 61 patients is too small to demonstrate the actual risk level for the development of osteonecrosis in patients taking oral bisphosphonates. As the authors wrote, a large-scale cohort study is the preferred study design to allow a conclusion about the contribution of oral bisphosphonates to the development of ONJ. We are aware of the fact that the current literature3 points to a relatively small risk for the development of oral bisphosphonate–related ONJ. However, similar to the approach of the American Dental Association Council on Scientific Affairs,3 we believe that the risks and benefits should be discussed with the patient early during the dental treatment plan. Although data from the Fugazzotto et al. study may be used as part of a meta-analysis in the future, their current conclusion cannot be used as a proof for the safety of dental implant placement in this patient population. After alternative dental treatment plans are presented to patients with their informed consent, the patients may decide to choose a treatment plan that includes the placement of dental implants. Nevertheless, until better data are available, the dentist should not ignore this risk.