# Osteoporosis and MRONJ in Dental Practice > Osteoporosis for BDS Medicine and Dental care: MRONJ definition with 8-week exposed bone, oral versus IV bisphosphonate risk and pre-therapy dental screening. - Canonical URL: https://prepelephant.com/topics/bds/general-medicine/osteoporosis-dental-patient - Exam / course: BDS · Subject: General Medicine - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Osteoporosis and MRONJ in Dental Practice", PrepElephant, https://prepelephant.com/topics/bds/general-medicine/osteoporosis-dental-patient ## Direct answer Osteoporosis itself contraindicates nothing in dentistry — the drugs that treat it do: bisphosphonates and denosumab are linked to medication-related osteonecrosis of the jaw (MRONJ), defined as exposed bone in the maxillofacial region persisting more than eight weeks in a patient on a bone-modifying agent without radiotherapy. Risk is stratified by route: oral bisphosphonates for osteoporosis (alendronate 70 mg weekly) carry low risk — commonly quoted around 0.1 percent — while intravenous bisphosphonates and denosumab in oncology carry risks an order of magnitude higher, and dentoalveolar surgery, especially extraction, is the dominant trigger. The highest-value dental act is chronological: screen and stabilise the mouth before the first tablet — restore, treat periodontitis, extract doomed teeth and complete prosthetic adjustments — because a clean mouth entering therapy almost never necroses. ## What you must remember - **MRONJ definition (quote all four limbs):** exposed bone in the jaw, persisting more than eight weeks, in a patient current or previously on antiresorptive or antiangiogenic therapy, with no history of radiotherapy to the region. - **Risk gradient:** oral bisphosphonate for osteoporosis roughly 0.01-0.1 percent; intravenous bisphosphonates (zoledronate) or denosumab in cancer — commonly quoted in single-digit percentages, several-fold to orders of magnitude higher. - **Risk multipliers:** dentoalveolar surgery (extraction first), glucocorticoid co-therapy, diabetes, smoking, poor oral hygiene, chemotherapy, and longer duration of therapy (beyond about three to four years of oral bisphosphonate). - **Pre-therapy protocol:** dental examination with radiographs before starting — eliminate infection sources, extract unrestorable teeth at least one to two weeks before therapy, complete prosthetic adjustment to remove trauma. - **Preventive maintenance on therapy:** meticulous hygiene, regular recall, treat conservatively — retained roots can often be left rather than extracted in low-risk osteoporosis patients, per clinical judgement and physician liaison. - **Established MRONJ management:** conservative — chlorhexidine rinses, antibiotics for infection, analgesia, superficial debridement; surgery reserved for refractory cases in specialist hands. - **Drug holiday caveat:** pausing bisphosphonates before extraction has weak evidence and is the prescriber's decision, not the dentist's — the exam wants the referral, not the unilateral stop. ## The extraction before the tablet A 63-year-old postmenopausal woman reports her physician is starting alendronate next month for osteoporosis. Your move: this is the golden window. Full examination with radiographs now: a root-carious lower molar beyond restoration and a periodontally hopeless premolar come out now, while her jaw healing biology is drug-free; periodontal therapy is completed; the over-extended denture flange that has been ulcerating her vestibule is corrected, because chronic mucosal trauma is itself a necrosis trigger. She enters therapy with a stable mouth — her lifetime MRONJ risk from the oral drug is now close to the background rate. Fast-forward three years: a fractured root surfaces in that same quadrant. The decision tree has changed: in a low-risk oral-bisphosphonate patient of three years' duration, extraction remains acceptable — atraumatic technique, alveoloplasty to remove sharp edges, primary closure where possible, chlorhexidine, close follow-up to epithelialisation. Had she instead been a myeloma patient on monthly zoledronate, the calculus flips — attempt conservative management first, involve the oncologist, and if extraction is unavoidable, do it in a specialist setting with the team informed. Same tooth, opposite risk class, different plan. ## Where students slip The definition is where marks leak: candidates remember "exposed bone" and forget the eight-week persistence, the drug exposure, or the no-radiotherapy limb — all four belong together, and radiation osteonecrosis is the separate entity excluded by the last limb. The second slip is conflating risk classes — treating a weekly-alendronate osteoporosis patient like a monthly-zoledronate cancer patient, either by refusing needed extractions (over-treatment of the low-risk) or by casual surgery in the high-risk (catastrophe). Third: the pre-therapy screening question is a sequencing question — "the physician phones about starting bisphosphonates; what do you do?" — and the pass answer is complete dental stabilisation first, not "no special action". Fourth, know the modern umbrella term MRONJ replaced BRONJ when denosumab and antiangiogenics joined the list; using only "BRONJ" dates a candidate. Fifth, the management of established MRONJ is conservative-first — chlorhexidine, antibiotics when infected, analgesia — with surgical sequestrectomy reserved for refractory disease; aggressive early resection is the wrong-answer option in every MCQ. ## Frequently asked questions ### What is the definition of MRONJ? Exposed jaw bone persisting more than eight weeks, in a patient taking or previously taking an antiresorptive or antiangiogenic agent, with no history of radiation therapy to the jaws. ### How does risk differ between oral and intravenous bisphosphonates? Oral therapy for osteoporosis carries roughly 0.01-0.1 percent risk; intravenous therapy in oncology (and denosumab at cancer doses) is an order of magnitude or more higher. ### What dental care should precede bisphosphonate therapy? Complete screening and stabilisation — restore, treat periodontitis, extract hopeless teeth and adjust prostheses — ideally at least a week or two before the first dose. ### Can extractions be done on a patient taking alendronate? Yes in most low-risk osteoporosis patients, atraumatically with chlorhexidine and close review; complex cases, longer therapy duration and cancer-dose therapy go to specialist coordination. ### How is established MRONJ managed? Conservatively — chlorhexidine rinses, systemic antibiotics for infection, analgesia and superficial debridement; surgical resection only for refractory cases in specialist hands.