When you’re told you have osteoporosis, the goal is simple: prevent fractures. Your bones are thinning, and a fall could mean a broken hip, a long hospital stay, or even loss of independence. That’s why doctors reach for bisphosphonates - drugs like alendronate (Fosamax), risedronate (Actonel), and zoledronic acid (Reclast). They work. They cut hip fracture risk by over 50% and spine fractures by nearly half. But there’s a quiet, rarely talked-about risk: jaw necrosis.
What Exactly Is Jaw Necrosis?
Medication-related osteonecrosis of the jaw, or MRONJ, happens when bone in your jaw becomes exposed and doesn’t heal. It’s not an infection you can brush off. The bone dies, stays visible for more than eight weeks, and often gets infected. You might feel pain, swelling, or notice a piece of bone sticking out after a tooth extraction. It sounds scary - and it is. But here’s the truth most people don’t hear: this is extremely rare if you’re taking bisphosphonates for osteoporosis.
The condition was first noticed in cancer patients getting high-dose IV drugs. But it showed up in osteoporosis patients too. The jaw is different from other bones. It’s constantly under stress from chewing, has thin gum tissue, and is full of bacteria. When bisphosphonates slow down bone repair, the jaw is the first place it shows up.
How Common Is This Really?
Let’s put numbers to fear. For someone taking oral bisphosphonates like Fosamax for osteoporosis, the risk of MRONJ is about 0.7 in 100,000 people per year. That’s less than one case in a city the size of Adelaide. A major study of 260,000 osteoporosis patients found no higher risk than people not taking these drugs at all. Compare that to cancer patients on IV bisphosphonates - their risk jumps to 1 in 100, or even higher if they’re also on denosumab.
Denosumab (Prolia) is another osteoporosis drug. It works differently - it’s an antibody, not a bisphosphonate. But it carries a higher risk of jaw necrosis. Studies show it’s 1.7 to 2.5 times more likely to cause MRONJ than oral bisphosphonates. Yet, it’s still rare overall. The real danger comes from combining drugs, like switching from bisphosphonates to denosumab. One 2024 study found 16% of cancer patients who did this developed jaw necrosis.
Why Do Bisphosphonates Cause This?
Bisphosphonates stick to bone and stop osteoclasts - the cells that break down old bone so new bone can grow. That’s good for your spine and hip. But your jaw needs constant remodeling. It’s the only bone that’s always in contact with bacteria, saliva, and chewing forces. When bone repair slows down, small injuries from dental work - even a routine cleaning - can’t heal properly.
The nitrogen-containing bisphosphonates (like alendronate and zoledronic acid) are the strongest. They stay in your bones for over 10 years. That’s why MRONJ can show up years after you stop taking the drug. The drug doesn’t vanish; it just sits there, quietly blocking bone repair.
Who’s at Highest Risk?
Not everyone who takes these drugs gets MRONJ. Risk goes up if:
- You’ve had a tooth extraction, dental implant, or major gum surgery after starting treatment
- You have gum disease or poorly fitting dentures
- You smoke or have diabetes
- You’re on IV bisphosphonates (like Reclast), especially for more than 3 years
- You’ve switched from bisphosphonates to denosumab
Most cases happen within 2 years of a dental procedure. But some show up 5 or even 8 years later. That’s why it’s not just about current use - it’s about your history.
What Should You Do Before Starting Treatment?
Before you take your first bisphosphonate pill or IV drip, see your dentist. Get a full exam. Fix cavities. Remove loose teeth. Treat gum disease. Don’t wait. Once you start, your jaw’s healing ability drops. Dental work becomes riskier.
The American Dental Association says this is non-negotiable. If you’re on IV bisphosphonates, your dentist should evaluate you within 30 days of your first dose. If you’re on oral bisphosphonates, get a checkup before you start. It’s not an extra step - it’s your safety net.
What If You’re Already on the Medication?
If you’ve been on alendronate for 5 years and your dentist says you need a tooth pulled, don’t panic. But don’t ignore it either. Talk to both your doctor and dentist. They need to work together.
Some doctors suggest a “drug holiday” - stopping the bisphosphonate for 3 to 6 months before major dental work. But here’s the catch: stopping increases your fracture risk. A 2024 study showed that stopping zoledronic acid for over a year cuts MRONJ risk by 82% - but raises your chance of a new hip or spine fracture by 28%. That’s not a trade-off you make lightly.
For most people on oral bisphosphonates, the risk of jaw necrosis is so low that skipping the drug isn’t worth it. The fracture risk is real. The jaw problem? Almost theoretical.
Signs You Should Watch For
MRONJ doesn’t always hurt. It can start silently. Look for:
- Bone sticking out of your gums after a tooth comes out
- Pain, swelling, or pus in your jaw
- Loose teeth with no obvious cause
- Numbness or heaviness in your jaw
Stage 1 is just exposed bone with no pain. Stage 2 has infection and pain. Stage 3 means the bone breaks, or the infection spreads to your face. Early detection is everything. If you see exposed bone, see your dentist immediately. Don’t wait for it to get worse.
Real Stories, Real Fears
One woman in Sydney, 68, took alendronate for 5 years. Her dentist found exposed bone after a cleaning. It took 18 months of antibiotics and surgery to heal. She’s now off the drug and terrified to go back.
Another man, 72, has been on Fosamax for 22 years. He’s had three extractions and two implants. Zero problems. His dentist says he’s the exception. He’s not. Most people don’t get this. But fear spreads faster than facts.
A survey of over 1,200 osteoporosis patients found 87% were anxious about jaw necrosis before dental work. But only 2.3% actually had it. Dentists are now so scared of MRONJ that some refuse to pull teeth - even when they’re infected and causing pain. That’s worse than the disease.
The Bigger Picture
Over 8 million Americans take bisphosphonates for osteoporosis. About 72% of eligible patients get treatment. But 38% quit within a year - mostly because of stomach upset, not jaw problems. That’s the real tragedy. People are afraid of a 1-in-100,000 risk and walking away from a drug that prevents life-altering fractures.
Denosumab and newer drugs like romosozumab are gaining ground. But they’re not better. Denosumab has a higher MRONJ risk. Romosozumab works fast but needs to be followed by another drug - and its long-term safety is still being studied.
Bisphosphonates are still the gold standard. They’ve been used for 30 years. We know how they work. We know how to prevent complications. And we know the fracture risk they prevent.
What’s Next?
Doctors are starting to personalize treatment. Instead of giving everyone the same drug for 5 years, they’re looking at biomarkers - like urinary NTX levels - to see who’s losing bone fastest. Those at highest fracture risk get longer treatment. Those at low risk might switch to safer options sooner.
By 2025, new guidelines will likely recommend checking your drug holiday timing based on the type of bisphosphonate. For zoledronic acid, stop 12+ months before major dental work. For ibandronate, 3 months may be enough. For oral alendronate? Most experts say: keep taking it.
The future isn’t about avoiding bisphosphonates. It’s about using them smarter - with better screening, better timing, and better communication between doctors and dentists.
Bottom Line: Don’t Let Fear Stop You
Yes, jaw necrosis is real. Yes, it’s serious. But for the vast majority of people with osteoporosis, the risk is microscopic compared to the risk of breaking a bone. You’re not choosing between a drug and a disease. You’re choosing between a tiny chance of a rare complication and a very real chance of losing your mobility, your independence, or your life.
Do this: See your dentist before you start. Keep your gums healthy. Tell your doctor if you need dental work. Don’t skip your meds because of fear. And if you’re worried, ask for a risk assessment - not a scare tactic.
Fractures don’t wait. Your jaw can heal. But a broken hip? That changes everything.
