Bisphosphonates and Orthodontic Treatment: What UK Patients Must Know

What are bisphosphonates and why are they prescribed?

Bisphosphonates are a class of drugs that inhibit the activity of osteoclasts — the cells responsible for breaking down bone. By reducing bone resorption they help maintain bone density, making them the most commonly prescribed treatment for osteoporosis in the UK. Common oral bisphosphonates include alendronate (Fosamax, branded and generic), risedronate (Actonel), and ibandronate (Bonviva). Intravenous bisphosphonates such as zoledronate (Zometa, Aclasta) are more potent and are used for cancer-related bone disease, hypercalcaemia of malignancy, and occasionally for osteoporosis. The route of administration and cumulative dose are key factors in assessing the risk to orthodontic treatment.

How bisphosphonates affect tooth movement

Orthodontic tooth movement relies on controlled bone remodelling — osteoclasts resorb bone on the pressure side of the tooth, and osteoblasts lay down new bone on the tension side, allowing the tooth to migrate through the jaw. Because bisphosphonates suppress osteoclast activity, they directly impair this remodelling process. In patients taking bisphosphonates — particularly IV forms or long-term oral therapy — tooth movement is significantly slower, less predictable, and occasionally negligible. Treatment timelines that would normally take 18 months may extend to 3 years or more, and some movements may simply not achieve the intended result within a clinically acceptable timeframe. This is not a reason to automatically refuse treatment, but it must be factored into the treatment plan and patient expectations.

BRONJ — bisphosphonate-related osteonecrosis of the jaw

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) — now more broadly termed medication-related osteonecrosis of the jaw (MRONJ) — is a serious condition where jawbone is exposed through the oral mucosa and fails to heal. It most commonly follows dental extractions or other invasive procedures in patients with a significant bisphosphonate burden. The intravenous forms carry a substantially higher risk than oral bisphosphonates; the risk from oral therapy is low but not negligible, particularly after 3 to 5 years of use. BRONJ presents as exposed, painful bone that does not heal, and management is difficult. This risk means that orthodontic extractions — which are relatively common for crowding management — carry additional scrutiny in bisphosphonate patients and should be avoided where possible or at minimum carefully risk-assessed.

What to tell your orthodontist and prescriber

You must disclose bisphosphonate use — current or historical — at your orthodontic consultation. Provide the name of the drug, the dose, the duration of use, and the indication. Your orthodontist should assess the cumulative risk alongside your prescribing GP or specialist. For patients on long-term oral bisphosphonates, a dental drug holiday — temporarily stopping the medication before invasive procedures — is sometimes considered, though evidence for its effectiveness in reducing BRONJ risk is limited and should be discussed with the prescribing clinician, not unilaterally decided. Stopping bisphosphonates without medical supervision in osteoporosis patients carries real fracture risk and must not be done without specialist input.

Is orthodontic treatment still possible on bisphosphonates?

In most cases, yes — with appropriate planning and adjusted expectations. Non-extraction orthodontic treatment in patients on oral bisphosphonates is generally feasible if the patient accepts a longer treatment timeline and the limitations on tooth movement speed and predictability. Clear aligners and fixed braces are both options; neither has a proven advantage over the other in this patient group. Treatment should be planned to minimise the risk of requiring extractions. If extractions are deemed unavoidable, the risk-benefit discussion should involve the prescribing clinician, and any procedure should be performed as atraumatically as possible with close post-operative monitoring. Patients on IV bisphosphonates with a significant cumulative dose represent a higher-risk group and the decision to proceed requires more careful multidisciplinary consideration.

How long after stopping bisphosphonates is it safer to proceed?

Bisphosphonates incorporate into bone and remain active for years after the last dose. Alendronate, for example, has a tissue half-life estimated at over 10 years. There is therefore no clear 'safe' period after stopping oral bisphosphonates. Drug holidays of 3 to 12 months before elective procedures are sometimes recommended based on expert opinion, but there is limited robust evidence that serum CTX levels — sometimes used as a surrogate marker of osteoclast activity — reliably predict BRONJ risk at the individual level. If you stopped bisphosphonates some years ago, your orthodontist should still be informed; the duration since last dose, cumulative dose taken, and route of administration all contribute to the residual risk profile.

Useful related pages

This guide is for general information only. It is not a diagnosis, treatment plan, or substitute for advice from a registered dentist or orthodontist.