Alendronate and medication-related osteonecrosis of the jaw (MRONJ)
What MRONJ actually is, the real risk on oral alendronate (Fosamax), and what to do before extractions or implants when you are on a bisphosphonate.
Never start, stop, or change a medication based on what you read here. Bring questions to your dentist, physician, pharmacist, or prescribing clinician.
Quick answer
The risk of MRONJ (medication-related osteonecrosis of the jaw) on oral alendronate is small but real. Estimates put it well below 1 percent for patients on oral bisphosphonates for osteoporosis, much higher in cancer patients on IV forms. The strongest risk factor is tooth extraction or invasive surgery, especially in the back of the lower jaw. The right move is not to avoid dental care; it is to coordinate it. Most extractions can be done safely with the right planning, and untreated infections cause more bone damage than alendronate does.
The mechanism
What MRONJ is and why bisphosphonates raise the risk
Bisphosphonates like alendronate work by slowing bone turnover. They bind to bone and inhibit the cells (osteoclasts) that break down old bone, which is what makes them effective against osteoporosis. The trade-off is that bone also remodels and heals more slowly. In a small subset of patients, particularly after surgical trauma to the jaw, the bone fails to heal properly and a section becomes necrotic (dies), creating an exposed area that does not close.
The jaw is uniquely vulnerable because it is one of the few bones routinely subjected to invasive procedures (extractions, implant placement, periodontal surgery) and one of the few bones exposed to the outside world through the mouth. An extraction socket in a patient on long-term bisphosphonates can sometimes fail to fill in with new bone the way it normally would.
The risk is much higher with intravenous bisphosphonates used in cancer treatment (zoledronic acid, pamidronate) than with oral alendronate used for osteoporosis. For oral alendronate, the risk after extraction is real but low, especially in patients who have been on the medication for less than four years.
Practical steps
What to do if you are on alendronate and need dental work
Signs to watch for
When to call your dentist
- An exposed area of bone in the mouth, even if it is not painful.
- A tooth socket that is not healing weeks after an extraction.
- Persistent jaw pain in the area of a recent procedure.
- A non-healing sore on the gums that has been there more than two weeks.
- Numbness or tingling in the jaw, lip, or chin (this can be a sign of bone involvement).
Common questions
What patients ask about Alendronate and jaw bone problems (mronj)
KYT Framework
KYT Framework connection
Four questions that shape how Alendronate and jaw bone problems (mronj) factor into dental planning.
Structure
Does jaw bone problems (mronj) change bone, gum tissue, saliva, enamel, or healing support?
Force
Will chewing, grinding, or bite pressure create added risk for vulnerable teeth or healing tissue?
Timing
Is jaw bone problems (mronj) something to prevent now, monitor, or evaluate soon?
Stability
What plan gives the mouth the best chance to stay stable?
Next steps
What to do about jaw bone problems (mronj)
The medication side is usually not the right thing to change. The dental side is. Here is where to go next.
Condition
Jaw osteonecrosis (MRONJ)
Risk levels by drug class, route, and duration.
Open →Cost
Extractions on bone-modifying meds
Why these cases often need atraumatic technique and pre-treatment coordination.
Open →Next step
Pre-treatment consultation
If you are going to start one of these meds, see a dentist first.
Open →More about Alendronate
Other medications and jaw bone problems (mronj)
Taking Alendronate and noticing jaw bone problems (mronj) changes?
Bring your medication list. KYT can evaluate cavity risk, gum health, and treatment timing in person.
Reviewed by Dr. Isaac Sun, DDS · KYT Dental Services · Fountain Valley, CA · Last reviewed: June 2026
This page is general patient education. It does not replace advice from your prescribing clinician, physician, pharmacist, or dentist. Medication information may change; verify with your clinical team.