Certain medications used in the treatment of osteoporosis, multiple myeloma, bone metastases and some oncological therapies increase the risk of a serious complication known as medication-related osteonecrosis of the jaw (MRONJ). This is a condition in which the bone of the maxilla or mandible does not heal properly after a dental procedure and remains exposed. The complication is rare but serious — it may require long-term treatment, sometimes surgical. The good news: in most cases it can be prevented if the patient reports the medications they are taking before any planned procedures. This article explains which drugs increase the risk, how patients in this group are assessed for implant placement, and what to do before an appointment.
What is MRONJ?
MRONJ (medication-related osteonecrosis of the jaw, formerly BRONJ — bisphosphonate-related osteonecrosis of the jaw) is exposure of the bone of the maxilla or mandible persisting for more than 8 weeks in a patient who is taking or has taken certain medications, without prior radiotherapy to the jaws. The mechanism is not fully understood — it is thought to involve impaired bone remodelling, effects on vascularity and the immune response. The definition and diagnostic criteria were systematised in the 2022 Position Paper of the American Association of Oral and Maxillofacial Surgeons (AAOMS), which serves as the international reference document.
Medications you MUST report before your appointment
The list is not exhaustive but covers the drug groups most commonly associated with MRONJ risk. Report each of these treatments regardless of whether you are currently taking them or have taken them in the past.
Oral bisphosphonates (most commonly for osteoporosis)
- alendronate — Fosamax and its generic equivalents
- risedronate — Actonel and generic equivalents
- ibandronate — Bonviva and equivalents
Intravenous bisphosphonates (severe osteoporosis, oncology)
- zoledronate — Aclasta (osteoporosis), Zometa (oncology)
- pamidronate — Aredia
RANK-L inhibitors
- denosumab — Prolia (osteoporosis, 60 mg every 6 months subcutaneously), Xgeva (oncology, 120 mg every 4 weeks)
Anti-angiogenic agents and selected targeted therapies
- bevacizumab — Avastin
- sunitinib — Sutent
- sorafenib — Nexavar
- aflibercept — Zaltrap
- selected mTOR inhibitors (e.g. everolimus — Afinitor)
If you are taking a medication not listed above but used in the treatment of osteoporosis, breast cancer, prostate cancer or myeloma, you should also report it to the clinician providing your dental treatment. The list of preparations continues to grow — new targeted therapies are appearing for which the association with MRONJ is still being evaluated.
Risk assessment table
| Drug / group | Route of administration | Duration of use | MRONJ risk assessment |
|---|---|---|---|
| Oral bisphosphonate (e.g. Fosamax) — osteoporosis | Oral | < 4 years, no risk factors | Low |
| Oral bisphosphonate — osteoporosis | Oral | > 4 years or corticosteroids | Moderate |
| Intravenous bisphosphonate — osteoporosis (Aclasta) | IV once yearly | Any duration | Low to moderate |
| Intravenous bisphosphonate — oncology (Zometa) | IV every 3–4 weeks | Any duration | High |
| Denosumab — osteoporosis (Prolia, 60 mg) | SC every 6 months | Any duration | Low to moderate |
| Denosumab — oncology (Xgeva, 120 mg) | SC every 4 weeks | Any duration | High |
| Anti-angiogenic (Avastin, Sutent) | IV / oral | Active oncological treatment | High |
This table is a simplification. Individual risk assessment also takes into account concurrent corticosteroid therapy, diabetes, smoking, the condition of oral hygiene and the history of previous procedures. It does not replace a consultation.
Implant placement in a high-risk patient — when it is contraindicated
Implant placement always involves preparation of the implant site (osteotomy) and the delivery of mechanical loading to the bone. These stimuli may, in a patient receiving intravenous bisphosphonates as part of oncological treatment or denosumab at a dose of 120 mg, initiate MRONJ. For this reason, in oncology patients receiving high-dose bisphosphonates (Zometa) or denosumab (Xgeva, 120 mg), implants are usually contraindicated — the alternatives are removable prostheses or conservative treatment to preserve the remaining dentition. However, according to the 2025 consensus of the International ONJ Taskforce, in patients with osteoporosis treated with oral bisphosphonates or denosumab (Prolia), implants may be placed safely without the need to interrupt therapy.
In patients in the low- and moderate-risk groups (typically: a short course of oral bisphosphonate for osteoporosis, denosumab Prolia) implant placement may be feasible, but only after a thorough assessment and, in some centres, following consultation with the physician managing the underlying condition. The decision is made on an individual basis, with documented discussion of the risks.
Mechanism — why do these drugs increase the risk?
Bisphosphonates inhibit the activity of osteoclasts (cells responsible for bone resorption), thereby slowing bone remodelling. When trauma occurs (extraction, implant placement) normal healing requires coordinated resorption and rebuilding — disruption of this balance can lead to necrosis. Denosumab acts through a different mechanism (blocking RANK-L) but the clinical effect is similar. Anti-angiogenic agents additionally impair tissue vascularity, which hinders healing. These mechanisms are cumulative — combining several drug groups raises the risk more than the sum of the individual risks.
Drug holiday — does discontinuing the medication help?
Temporary discontinuation of a bisphosphonate (drug holiday) before a planned procedure is sometimes considered in patients taking oral medications for osteoporosis. The 2022 AAOMS position indicated that the data on the effectiveness of a drug holiday are limited and that discontinuing the medication increases orthopaedic risk (osteoporotic fractures). The most recent 2025 consensus of the International ONJ Taskforce (Ali, Khan et al.) goes further — in patients with osteoporosis, antiresorptive therapy does NOT need to be discontinued before implant placement (weak recommendation, based on very low quality evidence). The decision is made by the physician managing the osteoporosis in consultation with the dentist, not by the patient on their own.
In the case of denosumab the situation is different — the effect of the drug wanes relatively quickly after administration, but its abrupt discontinuation carries the risk of rapid bone mass loss (rebound). Doses should not be missed without consulting the prescribing physician.
What to do before your appointment — practical steps
- Prepare a complete list of current and past medications, including doses and dates of commencement.
- Do not omit infrequently taken medications (e.g. zoledronate once a year) — these are often the most relevant.
- If you are undergoing oncological treatment, contact your treating oncologist — a consultation before the dental procedure may be required.
- Do not discontinue medications on your own. Any change must be agreed by the physician managing the underlying condition.
- Complete all necessary dental procedures BEFORE commencing high-dose bisphosphonate or denosumab therapy — this is the most effective preventive measure.
Key takeaways
- MRONJ is a rare but serious complication — in most cases it can be prevented.
- The list of drugs that increase the risk includes bisphosphonates (Fosamax, Bonviva, Aclasta, Zometa), denosumab (Prolia, Xgeva), selected anti-angiogenic agents (Avastin) and other targeted therapies.
- Each of these drugs — including those taken in the past — must be reported to the dentist before any procedure.
- In patients receiving high-dose oncological medications, implants are usually contraindicated; in the low-risk group the decision is made on an individual basis.
- The best prevention is to complete all necessary dental procedures before starting the underlying treatment.
- A drug holiday requires a decision by the prescribing physician — medications should not be discontinued on one's own.
Frequently asked questions
Can I have implants if I have osteoporosis?
In most cases, yes. According to the 2025 consensus of the International ONJ Taskforce, the risk of MRONJ in osteoporosis patients treated with bisphosphonates or denosumab is approximately 3 cases per 1,000 patients. The decision is made individually, taking into account the duration of therapy, drug dose, concurrent glucocorticoid treatment and the overall condition of oral health.
How long after starting the medication can MRONJ develop?
According to a 2024 systematic review, the mean time from commencement of antiresorptive therapy to the onset of MRONJ is 34 months, with a range of 3 months to 16 years. This means that both patients at the beginning of therapy and those who have been treated for many years should inform their dentist about the medications they are taking before every dental procedure.
Are oral bisphosphonates as risky as intravenous ones?
No. Oral bisphosphonates used in osteoporosis (Fosamax, Bonviva, Actonel) carry a low risk of MRONJ, especially when therapy has lasted less than 4 years and the patient is not taking glucocorticoids. Intravenous bisphosphonates used in osteoporosis (Aclasta, 5 mg once yearly) carry a risk comparable to oral bisphosphonates. Intravenous bisphosphonates in oncological treatment (Zometa, Aredia, administered every 3–4 weeks) carry a significantly higher risk due to the greater cumulative dose and higher drug concentrations in bone tissue.
What are the first symptoms of MRONJ that should cause concern?
According to the 2022 AAOMS definition — the international reference document — the most characteristic symptom of MRONJ is an area of exposed bone in the oral cavity persisting for more than 8 weeks. Other symptoms include: pain, swelling or redness of the gum around a tooth or implant, purulent discharge, loosening of a tooth without an obvious cause, numbness of the lip or chin. Any of these symptoms in a patient taking bisphosphonates or denosumab requires prompt consultation with a dentist.
Do bisphosphonates need to be stopped before an implant (drug holiday)?
According to the current 2025 consensus of the International ONJ Taskforce, in most patients with osteoporosis antiresorptive therapy does not need to be interrupted before implant placement. This recommendation is, however, weak and based on limited evidence — the decision is made by the physician managing the osteoporosis in consultation with the dentist. The patient should never discontinue medications on their own. In oncological treatment the guidelines remain more restrictive.
What should I do if I already have implants and my doctor prescribes bisphosphonates?
Implants placed before the commencement of antiresorptive therapy usually remain stable but require particular attention during the maintenance phase. In the practice of the Modern Dental & Orthodontics team we recommend: informing the dentist about the new medication, intensifying oral hygiene, attending reviews every 3–6 months and immediately reporting any pain, swelling or bone exposure around the implant. Prevention of peri-implantitis is especially important in these patients.
Can MRONJ be cured?
Yes, although it requires time and specialist treatment. Early stages are usually managed conservatively — antiseptic rinses (chlorhexidine), targeted antibiotic therapy, control of sources of infection. More advanced cases require surgical removal of necrotic tissue. Earlier diagnosis significantly improves the prognosis, which is why a patient taking high-risk medications should not delay consultation if worrying symptoms appear.
Is tooth extraction safer than an implant in a patient on bisphosphonates?
Not necessarily. Tooth extraction is also an invasive procedure for bone and is described as one of the most common triggers of MRONJ. In high-risk patients, endodontic (root canal) treatment with retention of the root is considered even if the tooth requires extensive prosthetic rebuilding — this is often a safer alternative than extraction. The decision is made by the dentist after individual risk assessment.
Read more:
- Dental Implants: https://klinikamdo.pl/en/offer/implantology/
- Dental implants and osteoporosis — is placement possible with weakened bones? https://klinikamdo.pl/en/blog/dental-implants-and-osteoporosis/
- What to avoid with dental implants? https://klinikamdo.pl/en/blog/what-to-avoid-with-dental-implants/
- Does getting a dental implant hurt? An honest account of pain, anaesthesia and healing https://klinikamdo.pl/en/blog/does-dental-implant-hurt-pain-anaesthesia/
- Dental implants — a comprehensive guide to treatment stages https://klinikamdo.pl/en/blog/dental-implants-comprehensive-guide/
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