From the Guidelines
Alveolar bone grafting in patients taking bisphosphonates does increase the risk of medication-related osteonecrosis of the jaw (MRONJ). According to the most recent and highest quality study, patients on oral bisphosphonates for less than 4 years without additional risk factors may proceed with bone grafting with minimal increased risk 1. However, patients on oral bisphosphonates for more than 4 years or those on intravenous bisphosphonates (like zoledronic acid or pamidronate) have significantly higher risk and should consider alternative treatments when possible.
Some key points to consider:
- The risk of MRONJ is higher in patients taking intravenous bisphosphonates, with a cumulative hazard of ONJ increasing from 1% after 12 months to 11% at 4 years 1.
- A comprehensive dental examination and appropriate preventive dentistry should be performed before bisphosphonate therapy, and active oral infections should be treated before starting treatment 1.
- Patients should maintain excellent oral hygiene and avoid invasive dental procedures, if possible, while on therapy 1.
- If bone grafting is absolutely necessary, a drug holiday of 2 months before and 3 months after surgery is recommended for oral bisphosphonate users, though this approach remains controversial.
- For high-risk patients, consultation with the prescribing physician about temporarily discontinuing bisphosphonate therapy is essential.
- Prophylactic antibiotics (typically amoxicillin 500mg three times daily starting 1 day before surgery and continuing for 7 days) and chlorhexidine rinses may help reduce infection risk during the healing period.
The increased risk of MRONJ occurs because bisphosphonates inhibit bone remodeling and angiogenesis, which are critical for healing after invasive dental procedures. These medications accumulate in the jawbone and remain active for years, particularly affecting areas of high bone turnover like extraction sites or bone graft recipient sites.
From the Research
Medication-Related Osteonecrosis of the Jaw (MRONJ) and Alveolar Bone Grafting
- There is no direct evidence to suggest that alveolar bone grafting increases the risk of MRONJ in patients taking bisphosphonates 2, 3, 4, 5, 6.
- However, dental procedures such as tooth extraction, periodontal surgery, and oral implant placement have been associated with an increased risk of MRONJ in patients taking bisphosphonates 3, 5.
- The pathophysiology of MRONJ is not fully understood, but it is thought to be related to the suppression of bone resorption and the formation of necrotic bone tissue 2, 3, 4.
- Prevention of MRONJ is crucial, and this can be achieved through careful dental preparation, oral hygiene instructions, and prophylactic dental treatment before starting bisphosphonate therapy 2, 5, 6.
Risk Factors for MRONJ
- Bisphosphonate exposure is a major risk factor for MRONJ, particularly with high cumulative doses 2, 3, 6.
- Other risk factors include dental diseases and procedures, age, sex, anatomical factors, medical issues, and hereditary factors 2.
- The use of antiresorptive medications such as denosumab also increases the risk of MRONJ 2, 6.
Treatment and Prevention of MRONJ
- Treatment of MRONJ is challenging, and the optimal therapy strategy is still to be established 3.
- Prevention is key, and this can be achieved through a multidisciplinary team approach, including dentists, oncologists, and maxillofacial surgeons 3, 6.
- Local application of a rescue bisphosphonate prior to dental surgery may decrease the amount of legacy N-BP drug in proximate jawbone surfaces and reduce the risk of osteonecrosis 4.