Osteoporosis Medications: Understanding Bisphosphonate Risks and Jaw Necrosis

When you're diagnosed with osteoporosis, your doctor likely talks about reducing fracture risk - and for good reason. One in two women over 50 will break a bone due to weak bones. Bisphosphonates like alendronate (Fosamax), risedronate (Actonel), and ibandronate (Boniva) have been the go-to treatment for decades because they work. They cut hip fracture risk by over 50% and spine fractures by nearly half. But somewhere in the fine print, you might hear about a rare but scary side effect: medication-related osteonecrosis of the jaw, or MRONJ.

What Exactly Is MRONJ?

MRONJ isn't just a mouth sore. It’s when bone in your jaw becomes exposed and doesn’t heal for more than eight weeks. You might notice it after a tooth extraction, a denture adjustment, or even a routine cleaning. The bone sticks out through the gum, sometimes with pain, swelling, or infection. It doesn’t happen overnight. It takes months - sometimes years - to show up.

This isn’t random. It happens because bisphosphonates lock themselves into your bones and stay there - for over 10 years in some cases. They stop bone breakdown by killing off the cells (osteoclasts) that normally clean out old bone. That’s great for keeping your spine and hips strong. But your jaw? It’s different. It remodels bone 10 times faster than your thigh bone. That means it’s more active, more exposed to bacteria from your mouth, and more vulnerable when healing gets blocked.

The Real Risk: How Common Is It?

Let’s get real. If you’re taking an oral bisphosphonate for osteoporosis, your chance of getting MRONJ is about 0.7 in 100,000 people per year. That’s less than one case in a million. For comparison, you’re more likely to be struck by lightning than develop this condition.

But here’s where it gets confusing: some people hear horror stories. A woman on a patient forum spent 18 months dealing with exposed bone after a cleaning. Another guy had 22 years on Fosamax and never had an issue. Both are true. The problem isn’t the drug - it’s the combination of factors.

Studies show that 63% of MRONJ cases in osteoporosis patients follow a dental procedure - usually an extraction. If you already have gum disease, loose teeth, or an infection before starting treatment, your risk goes up. The medication doesn’t cause it. It just makes healing harder.

And here’s the twist: intravenous bisphosphonates - like zoledronic acid (Reclast) - carry a higher risk than pills. Why? Because they deliver a much stronger dose directly into your bloodstream. Cancer patients on high-dose IV versions have a 3-16% risk. But for osteoporosis? That same drug, given once a year at a lower dose, still keeps the risk under 1 in 100,000.

Bisphosphonates vs. Denosumab: Which Is Safer?

Denosumab (Prolia) is the newer option. It’s not a bisphosphonate - it’s a monoclonal antibody that also stops bone loss. It works just as well at preventing fractures. But here’s the catch: studies show it carries 1.7 to 2.5 times the risk of MRONJ compared to oral bisphosphonates.

That doesn’t mean it’s unsafe. It just means if you’re choosing between treatments, your dentist and doctor need to weigh the numbers. Denosumab requires injections every six months. If you miss one, bone loss can rebound fast. Bisphosphonates, once taken, stick around for years. That’s why stopping them suddenly - even to avoid MRONJ - can be dangerous.

A 2024 study in Nature Communications found that if you stop IV zoledronate for more than a year, your MRONJ risk drops by 82%. But your fracture risk jumps by 28%. That’s not a trade-off most patients can afford.

What Should You Do Before Starting Treatment?

The best way to avoid MRONJ is to start with a healthy mouth. The American Dental Association and the American Association of Oral and Maxillofacial Surgeons both say: get a full dental exam before you begin bisphosphonates. Fix cavities. Remove loose teeth. Treat gum disease. Don’t wait until you’re on the drug.

If you’re already taking a bisphosphonate and need dental work, don’t panic. Most routine cleanings, fillings, and crowns are safe. The big red flag is extraction or surgery. Talk to your dentist and your doctor together. They might recommend a short drug holiday - especially if you’ve been on IV therapy for 3-4 years. But don’t stop your medication on your own. That could lead to a spine fracture.

Signs to Watch For

MRONJ doesn’t always hurt at first. In fact, 35% of cases start with no symptoms - just exposed bone. Here’s what to look for:

• Bone sticking out through the gum after a tooth is pulled
• Pain or swelling in the jaw that doesn’t go away
• Loose teeth with no clear reason
• Pus or bad taste in the mouth that won’t clear up
• Delayed healing after dental work

If you notice any of these, see your dentist immediately. Early-stage MRONJ can often be managed with antibiotics, mouth rinses, and avoiding further trauma. Later stages may need surgery - but that’s rare in osteoporosis patients.

Why Do Dentists Get Nervous?

Many dentists are scared of MRONJ - not because it’s common, but because it’s serious. Some refuse to extract teeth in patients on bisphosphonates. Others over-test, over-wait, or over-treat. That’s not helpful. It leads to delays in care, more pain, and sometimes worse outcomes.

Doctors need to know the real numbers. A 2023 survey found 87% of osteoporosis patients worry about MRONJ before dental work. But only 2.3% ever experience it. That fear is driving people away from needed care. One patient on HealthUnlocked said, “My dentist refused to fix my broken crown because I take Fosamax. I ended up with an abscess.”

The truth? Most dentists don’t have access to the latest research. They’re working off old guidelines or fear-based training. That’s changing. The ADA is updating its recommendations for 2025 to include data on how long you’ve been off the drug - called “time since last dose.” That will help dentists make smarter decisions.

What’s the Bottom Line?

If you have osteoporosis, the risk of breaking a hip or spine is far greater than the risk of jaw necrosis. Bisphosphonates save lives. They keep people walking, independent, and out of the hospital. The 11-year data from the Fracture Intervention Trial shows alendronate reduces hip fracture risk by 55%. That’s not a small win.

MRONJ is real. But it’s rare. And it’s preventable. You don’t need to avoid dental care. You need to be prepared. Get your mouth checked before starting treatment. Keep your gums healthy. Tell your dentist what you’re taking. Don’t skip your annual cleanings. And never stop your medication without talking to your doctor.

The future is coming. Researchers are testing blood and urine markers to find who’s most at risk for MRONJ. In a few years, we might be able to say: “You’re low risk - keep going.” Or: “You’re high risk - let’s switch to something else.” Until then, the balance is clear: protect your bones, care for your mouth, and trust the science.