Osteoporosis Medications: Bisphosphonates and Jaw Necrosis Risks

When you’re diagnosed with osteoporosis, your doctor’s main goal is simple: prevent broken bones. That’s why medications like bisphosphonates are so widely prescribed. They’re effective, affordable, and backed by decades of research showing they can cut hip and spine fracture risk by up to 70%. But for every benefit, there’s a shadow - and for some people, that shadow is a rare but serious condition called medication-related osteonecrosis of the jaw, or MRONJ.

What Exactly Is MRONJ?

MRONJ isn’t just a sore tooth or a minor infection. It’s when bone in your jaw becomes exposed and doesn’t heal for more than eight weeks. You might see it as a piece of bone sticking out near a pulled tooth, or feel persistent pain and swelling in your gums. It doesn’t happen overnight. It often shows up months or even years after a dental procedure - like an extraction - and it’s almost always linked to drugs that slow down bone breakdown.

The name used to be BRONJ - bisphosphonate-related osteonecrosis of the jaw. But now we know other drugs, like denosumab (Prolia), can cause it too. So the updated term is MRONJ: medication-related osteonecrosis of the jaw. The key trigger? Drugs that stop osteoclasts - the cells that naturally remove old bone so new bone can grow. Without that turnover, your jawbone can’t repair itself after trauma or infection.

Why the Jaw? It’s Not Just Any Bone

Why does this happen in the jaw and not the hip or spine? It comes down to biology. The bone in your jaw - especially the alveolar bone that holds your teeth - turns over about ten times faster than the bone in your leg or spine. That means it absorbs more of the medication. Add to that the constant presence of bacteria from your mouth, the stress of chewing, and thin gum tissue that’s easy to damage, and you’ve got a perfect storm.

Think of it this way: your leg bone doesn’t get brushed twice a day or chew on hard food. Your jaw does. And if the bone can’t heal because the drugs have shut down its repair system, even a small cut or infection can turn into something serious.

How Common Is It Really?

Here’s the truth most patients don’t hear: for someone taking oral bisphosphonates like alendronate (Fosamax) or risedronate (Actonel) for osteoporosis, the risk is incredibly low. Studies show about 0.7 cases per 100,000 people per year. That’s less than one in a hundred thousand. For context, you’re far more likely to be struck by lightning than develop MRONJ from these pills.

But the numbers change dramatically with intravenous (IV) drugs. Zoledronic acid (Reclast), given once a year for osteoporosis, carries a risk of about 1 in 100,000 per year. That’s still rare - but it’s 14 times higher than oral versions. And if you’re getting high-dose IV bisphosphonates for cancer, the risk jumps to 3% or more.

Denosumab (Prolia), a newer osteoporosis drug, may carry a slightly higher risk than oral bisphosphonates - about 1.7 to 2.5 times higher. But even then, the absolute risk remains very low. A 2024 study of 260,000 osteoporosis patients found no increased risk of jaw necrosis in those taking oral bisphosphonates compared to those not taking them at all.

The Real Culprit: Dental Work and Poor Oral Health

Most cases of MRONJ in osteoporosis patients happen after a dental extraction. In fact, 63% of cases reported to the American Association of Oral and Maxillofacial Surgeons followed a tooth removal. The median time from surgery to diagnosis? Just over two years.

But here’s the critical point: if you have gum disease, loose teeth, or untreated infections before starting bisphosphonates, your risk goes up. That’s why experts say the best way to prevent MRONJ is to get your mouth healthy before you start the medication. A full dental exam, cleaning, and any needed extractions or fillings should happen before you take your first pill.

Dr. Cesar Migliorati, who helped first identify this link in 2003, puts it bluntly: “If a lot of patients had gum disease or tooth infection before starting treatment, that could have raised the rate of ONJ.”

Drug Holidays: A Risky Balancing Act

Some doctors consider a “drug holiday” - stopping the medication for a few months before major dental work - to lower MRONJ risk. But this isn’t simple. Bisphosphonates stay in your bones for years, even after you stop taking them. A 2024 study in Nature Communications found that stopping IV zoledronic acid for more than 365 days reduced MRONJ risk by 82%. But it also increased the risk of a new fracture by 28%.

That’s the tightrope walk. Stopping the drug to protect your jaw might put your spine or hip at risk. For most people on oral bisphosphonates, the advice is simple: don’t stop without talking to your doctor. The fracture risk is real. The jaw risk? Still extremely low.

What Should You Do If You’re on Bisphosphonates?

• Before starting: Get a full dental checkup. Fix cavities, treat gum disease, and remove problem teeth. Don’t delay.
• While taking it: Brush and floss daily. See your dentist every six months. Tell them you’re on a bisphosphonate. Avoid invasive procedures if possible - but don’t refuse needed care out of fear.
• If you need an extraction: Work with both your doctor and dentist. They can coordinate care. In most cases, extraction is safe if your mouth is healthy and you’re on oral meds.
• Don’t panic: If you notice exposed bone, pain, or swelling after dental work, see your dentist immediately. Early treatment works better.

What About Denosumab?

Denosumab (Prolia) works differently than bisphosphonates. Instead of sticking to bone for years, it’s a monthly or biannual injection that blocks a protein called RANKL. It’s just as good at preventing fractures - but it clears from your body faster. That means if you stop taking it, your bone density can drop quickly. That’s why you can’t just quit it cold turkey.

And yes, it carries a slightly higher MRONJ risk than oral bisphosphonates. But again - the absolute risk is still very low. A 2024 study of breast cancer patients found that switching from bisphosphonates to denosumab increased ONJ risk to 16%. But that was in cancer patients getting much higher doses. For osteoporosis patients, the risk remains under 1%.

What’s the Bottom Line?

The fear of jaw necrosis is real. Many patients worry about it more than they worry about breaking a hip. And that’s understandable. But the data doesn’t lie: for people with osteoporosis, the benefits of bisphosphonates far outweigh the risks.

You’re more likely to die from a hip fracture than from MRONJ. A 10-year study showed that taking alendronate reduces hip fracture risk by 55%. That’s life-changing. And for most people, the chance of developing MRONJ is less than 1 in 10,000.

That’s why major medical groups - the American Dental Association, the American Association of Oral and Maxillofacial Surgeons, and the National Osteoporosis Foundation - all agree: don’t avoid treatment because of fear. Do your part: keep your mouth healthy, tell your dentist you’re on these meds, and don’t skip your annual checkups.

What’s Changing in 2025?

Research is moving fast. The 2024 study on drug holidays is already changing how doctors think. The ADA is updating its guidelines for 2025 to include new data on how long you should wait after stopping IV bisphosphonates before dental surgery.

Future tools may help too. Doctors are testing urine tests that measure bone turnover markers - like NTX - to find out who’s at highest risk for MRONJ. The goal? Personalized treatment. Someone with low bone turnover and perfect oral health might stay on bisphosphonates for 10 years. Someone with gum disease and high turnover might switch to a different drug after 3-5 years.

For now, the message stays simple: treat your osteoporosis. Protect your teeth. Talk to your team. And don’t let fear keep you from living without fear of breaking a bone.