Osteoporosis Medications: Bisphosphonates and Jaw Necrosis Risks

When you’re taking medication to protect your bones from breaking, the last thing you want is for that same drug to cause damage somewhere else. That’s the quiet tension around bisphosphonates, the most common drugs used to treat osteoporosis. They work incredibly well-cutting hip fracture risk by over half in long-term users-but for a tiny number of people, they can trigger a rare and painful condition called medication-related osteonecrosis of the jaw (MRONJ). It’s not something you hear about often, but if you’ve been on these drugs for years and are about to have a tooth pulled, it’s worth knowing the real risks.

What Exactly Is MRONJ?

MRONJ isn’t a quick infection or a bad toothache. It’s when bone in your jaw becomes exposed and doesn’t heal. You might notice it after a dental procedure-like a tooth extraction-when the gum doesn’t close over the bone. The bone sticks out, might feel sore, or even get infected. It has to last for at least eight weeks before doctors will call it MRONJ. It doesn’t happen from brushing too hard or gum disease alone. It’s tied directly to drugs that stop bone from breaking down.

Think of your bones like a living structure. They’re constantly being broken down and rebuilt. Bisphosphonates slow down the breakdown side of that process. That’s good for your spine and hip, but your jaw is different. It’s under constant stress-chewing, talking, even clenching your teeth. And it has way more blood flow and turnover than your thigh bone. That makes it more sensitive when the healing process gets stuck.

How Common Is It Really?

Let’s get real: the risk is tiny. For someone taking oral bisphosphonates like alendronate (Fosamax) or risedronate (Actonel) for osteoporosis, the chance of developing MRONJ is about 0.7 in 100,000 people each year. That’s less than one case per 140,000 people annually. To put that in perspective, you’re more likely to be struck by lightning in a given year.

But numbers don’t always tell the whole story. A 2024 study in Nature Communications looked at over 600 patients and found that the risk jumps if you’ve had a tooth pulled while on the drug. About 63% of MRONJ cases in osteoporosis patients followed a dental extraction. The average time from the procedure to symptoms? Just over two years. That delay is why many people don’t connect the dots.

Here’s the twist: people on intravenous bisphosphonates-like zoledronic acid (Reclast)-have a higher risk, but that’s mostly because they’re getting much higher doses. Those doses are usually given to cancer patients, not people with osteoporosis. For osteoporosis patients, the IV version is given just once a year. Still, the dose matters. A 5mg IV dose for osteoporosis is 10 times higher than the oral weekly dose, and it stays in your bones for over a decade.

Bisphosphonates vs. Denosumab: Which Is Riskier?

Denosumab (Prolia) is another common osteoporosis drug. It works differently than bisphosphonates-it’s an antibody that blocks a protein involved in bone breakdown. It’s just as good at preventing fractures, but studies show it might carry a slightly higher risk of jaw necrosis. One 2024 study found that among cancer patients, 12% on denosumab developed jaw necrosis, compared to 3% on bisphosphonates. Even in osteoporosis, the risk is estimated to be 1.7 to 2.5 times higher than with oral bisphosphonates.

So why do doctors still prescribe bisphosphonates? Because they’ve been around longer, have more long-term data, and are cheaper. Alendronate has been on the market since 1995. Over 8 million Americans are on it. And the data is clear: over 11 years, it reduces hip fractures by 55%. That’s huge. For most people, the benefit far outweighs the risk.

Who’s Most at Risk?

It’s not just about the drug. Your dental health before you start matters more than you think. If you already have gum disease, loose teeth, or untreated infections, your risk goes up. The jawbone in people with poor oral health is already under stress. Add a drug that slows healing, and it’s a perfect storm.

One dentist in Florida who helped discover this link back in 2003 said it plainly: "If a lot of patients had gum disease or tooth infection before starting treatment, that could have raised the rate of ONJ."

Other risk factors:

• Smoking
• Diabetes
• Long-term use (over 3-5 years)
• Recent dental surgery, especially extractions
• Corticosteroid use

Interestingly, studies show that people who get a full dental check-up before starting bisphosphonates cut their risk dramatically. The American Association of Oral and Maxillofacial Surgeons recommends a full exam within 30 days of starting IV therapy. For oral meds, it’s still a good idea.

What Should You Do If You’re on These Drugs?

Here’s the practical advice:

1. Don’t stop your medication because you’re scared of jaw problems. The risk of breaking a hip or spine is far higher.
2. See your dentist regularly-at least twice a year. Tell them you’re on a bisphosphonate or denosumab.
3. Fix dental problems before you start. Get cavities filled, treat gum disease, and consider pulling badly damaged teeth before you begin treatment.
4. Avoid invasive procedures if possible. If you need a tooth pulled while on the drug, your dentist might delay it or take extra steps to reduce infection risk.
5. Keep your mouth clean. Brush gently, floss daily, and rinse with salt water if your gums feel tender.

Some people wonder about "drug holidays"-taking a break from the medicine. A 2024 study found that stopping IV bisphosphonates for more than a year cuts MRONJ risk by 82%. But here’s the catch: stopping for a year also increases your fracture risk by 28%. That’s not a trade-off most people should make.

What Do Real Patients Say?

Online forums are full of stories. One woman on the National Osteoporosis Foundation forum shared that after five years on alendronate, she developed exposed bone after a cleaning. It took 18 months of antibiotics and surgery to heal. Another person on Reddit said they’d been on Fosamax for 22 years, had multiple extractions and implants, and never had a problem.

Most people never see a single issue. But fear spreads. A 2023 survey found 87% of osteoporosis patients worry about jaw necrosis before dental work. Yet only 2.3% ever had it happen. Meanwhile, many dentists are so cautious they refuse to do routine cleanings or fillings. That’s a problem too. Avoiding dental care because you’re scared of MRONJ can lead to worse outcomes-like infections, abscesses, or losing teeth.

The Bottom Line

Bisphosphonates save lives. They prevent fractures that can lead to long-term disability or death, especially in older adults. MRONJ is real, but it’s rare. It’s not something you should lose sleep over. But it’s something you should be smart about.

If you’re on one of these drugs:

• Keep your mouth healthy.
• Don’t skip dental visits.
• Talk to both your doctor and dentist together.
• Don’t stop your medicine unless your doctor says so.

The goal isn’t to avoid the drug. It’s to use it safely. And for most people, that means taking it as prescribed-with good dental care as your backup plan.