Implant Retention Versus Removal for MRONJ at Implant Sites: A Prospective Study

Medication-related osteonecrosis of the jaw (MRONJ) is a condition that can occur in patients who take medications such as antiresorptive drugs for osteoporosis and other bone-related systemic diseases. Although the overall risk is relatively low, the number of affected patients is increasing as the population ages and dental implants are increasingly used to restore chewing function. When MRONJ develops at an implant site, deciding whether to keep or remove the implant becomes a difficult clinical problem.

Current treatment recommendations for MRONJ are mainly based on disease stage. However, in situations where only part of the bone around an implant is affected, and the entire implant surface is not involved, there are no clear, evidence-based criteria to guide the decision between implant retention and implant removal. Some clinicians recommend removing all implants associated with necrotic bone to reduce the risk of recurrence. Others attempt to preserve implants that appear less severely affected. Implant retention may carry a risk of delayed healing or recurrence, whereas implant removal may cause additional surgical trauma that could potentially worsen the condition. Therefore, more objective criteria are needed to support clinical decision-making.

In peri-implantitis, another disease affecting the tissues around implants, the amount of bone loss observed on radiographs is often used as a reference for treatment decisions. Traditionally, implant removal has been considered when bone loss reaches approximately 50-60% of the implant length. When bone loss is less extensive, treatment aimed at preserving the implant may be attempted. However, it is unknown whether a similar bone loss threshold applies to patients with implant-related MRONJ.

The purpose of this prospective study is to evaluate whether the extent of peri-implant bone loss-particularly within the range of 20% to 60% of the implant length-can serve as a practical reference for deciding whether to retain or remove an implant in patients with implant-related MRONJ. By comparing clinical outcomes between implant retention and implant removal within this range of bone loss, this study aims to determine whether a bone-loss-based criterion can support treatment decisions.

The primary outcome of the study is complete mucosal healing at 6 months after treatment. Additional outcomes, including radiographic changes assessed by cone-beam computed tomography (CBCT) and recurrence of MRONJ-related clinical signs, will also be evaluated during the 1-year follow-up period after treatment initiation. CBCT imaging will be performed at 6 and 12 months after treatment to assess bone changes over time. Approximately 50 patients will be enrolled in this single-center prospective study. The findings are expected to provide structured clinical data to guide implant management decisions in patients with implant-related MRONJ.