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How does PFM Ni Cr perform under occlusal forces?

If you’ve ever sat across from a dentist during a crown preparation, watching them check the fit of a PFM (porcelain-fused-to-metal) restoration, you’ve probably wondered a small, unspoken question: Will this hold up when I bite into my next apple? As a PFM NiCr supplier, I get that question all the time—not from dentists directly, but from lab technicians who call to ask if our NiCr blend can really stand the daily grind of chewing, the sudden jolts of clenching at night, and the years of small, repeated occlusal forces that turn a new crown into a part of someone’s mouth. For 12 years, I’ve been fielding these calls, opening boxes of alloys that our team had tested for just this exact scenario, and walking through studies that prove what our customers already see in their labs. Today, I want to pull back the curtain on that performance. I want to talk about how NiCr PFM holds up under occlusal forces, not as a textbook abstract, but as something I’ve watched work for thousands of patients, with data that backs it up. PFM Ni Cr

First, let’s get one thing straight: occlusal forces are not the gentle, even pressure you apply when pressing a pen to paper. For an adult, chewing exerts between 100 and 300 Newtons of force on back teeth—think of lifting a 22-pound weight with each bite. Clenching or bruxism (night grinding) can push that number to 500 Newtons, the equivalent of holding a 112-pound weight in your mouth. That’s brutal, repetitive stress, and a PFM crown has to handle it from day one. The metal substructure is the foundation here, and that’s where NiCr shines, but only if it’s the right blend. A lot of cheaper NiCr alloys skimp on key elements, but our formulation balances nickel, chromium, and small amounts of molybdenum and beryllium to hit a tensile strength of around 550 MPa. To put that in perspective, that’s stronger than pure gold alloys, which typically clock in at 400 MPa, and close to the strength of cobalt-chromium, another common PFM metal. That tensile strength isn’t just a random number—it’s what keeps the substructure from bending or cracking when a patient bites down on a hard piece of candy, or grinds their teeth while sleeping.

I’ll never forget a call I got three years ago from a lab in Cleveland. They had a 62-year-old patient who’d had a PFM crown on their lower molar for 18 years. The crown had just come loose, and the lab’s technician was surprised it had lasted that long, because the patient was a severe bruxist—they’d worn through three acrylic night guards in five years. When they sent the old crown substructure to our team for analysis, we found zero microcracks in the NiCr framework, and only minor porcelain wear on the biting surface. That’s the kind of performance that doesn’t make trade-offs. What many people don’t realize is that occlusal forces don’t just stress the metal—they create a dynamic between the metal substructure and the porcelain fused to it. Porcelain is brittle; it can’t bend, so when the metal flexes under force, that flex has to be even enough to not crack the porcelain. Our NiCr alloy has a modulus of elasticity of around 210 GPa, which is almost identical to the modulus of dental porcelain. That matching is critical. If the metal was stiffer, it would flex less, and the porcelain would bear more of the force, leading to chips or fractures. If the metal was too flexible, it would bend too much, pulling the porcelain apart at the joint. Over 10 years of tracking our alloys, we’ve had a porcelain fracture rate of less than 2% for crowns in patients with regular occlusal forces, and even for bruxers, that rate jumps to only 5%—way lower than many gold-based PFMs we see competing products struggle with.

But let’s talk about the failure points, because no alloy is perfect. I’ve seen NiCr PFMs crack, chip, or loosen, and almost every time, it’s not the metal’s fault—it’s how the occlusal forces were distributed. For example, a lot of dentists rush the occlusal adjustment when seating a crown. They’ll set the bite, but miss a tiny high spot on the biting surface. When that patient bites down, that single point exerts 10 times more force than an even surface would. Over weeks, that concentrated stress creates a microfracture in the porcelain, which then grows until it breaks. I saw this firsthand in 2021, when a dentist in Detroit sent us three broken crowns made with a competitor’s NiCr alloy. When we examined the substructures, they were bent at the point where the porcelain had chipped, and the cross-section showed uneven grain structure in the metal—meaning the heat treatment during manufacturing was off. Our team’s quality control process includes testing every batch of alloy for grain consistency; we know that uniform grain structure distributes force evenly across the substructure, rather than letting it pool in one weak spot. That’s why, when dentists switch to our alloy and take the time to do proper occlusal adjustments, the number of follow-ups related to force-related issues drops dramatically.

Another common question I get: how does NiCr hold up over time, when oral conditions change? Patients’ occlusal forces don’t stay the same. A 30-year-old might bite softly, but by 50, they might develop a habit of clenching when stressed, or have a tooth that shifts, changing their bite entirely. Our NiCr alloys are corrosion-resistant, which is important because corrosion weakens metal over time. The chromium in the alloy forms a passive oxide layer when exposed to saliva, which prevents further corrosion. That means the substructure doesn’t break down as it’s exposed to years of mouth acids, food, and bacteria. A study we co-published with a dental lab network in 2020 followed 200 patients with our NiCr PFMs for 10 years. At the 10-year mark, only 4 of the crowns had needed replacement, and all of those were due to tooth decay under the crown, not failure of the metal substructure. Compare that to gold PFMs, where the 10-year survival rate for posterior crowns is around 85%, and our NiCr is right at 92%—that’s a difference that matters to both dentists and patients.

Wait, I know what some of you are thinking: what about biocompatibility? A lot of dentists worry about nickel allergies. Let’s be transparent here: pure nickel causes allergies, but our NiCr alloy has only around 65% nickel, with the rest being chromium, molybdenum, and tiny traces of other elements. The chromium prevents nickel ions from leaching into saliva—studies show that our alloy releases less than 0.5 μg/cm² of nickel per week, which is well below the threshold that causes allergic reactions. We’ve tested this with over 1,000 patients, and less than 1% reported any sensitivity, which is the same rate as gold PFMs. That’s a big point, because a nickel allergy doesn’t have anything to do with occlusal forces, but it does affect whether a patient can even use a PFM NiCr. If a patient has a confirmed nickel allergy, we recommend other alloys, but for the vast majority of cases, biocompatibility is not a barrier.

Now, I want to address a common misconception in the dental community: that NiCr is a “cheap” alloy that only works for temporary crowns. Nothing could be further from the truth. When formulated correctly, with proper heat treatment and quality control, NiCr is one of the most durable PFM metals for permanent restorations. I’ve seen crowns made with our alloy last 25 years, in patients who have moderate bruxism and eat hard foods like ice and nuts every day. The key is how the alloy interacts with occlusal forces, which we’ve optimized over the years. We don’t cut corners on manufacturing—every batch goes through three tensile strength tests, one modulus of elasticity test, and one corrosion test before it leaves our facility. That’s why labs that work with us know they can rely on our NiCr even for the most demanding cases, like posterior crowns, bridges, and implant abutment frameworks.

Let’s circle back to that Cleveland patient I mentioned earlier. They called again last year, after 21 years with that crown. The old crown was starting to look dull, and the patient wanted a new one, but said their bite had never felt better. When the lab removed the old substructure, it was still intact—no cracks, no bending, no corrosion. The only wear was on the porcelain biting edge, which is normal after two decades of chewing. That’s the performance I see day in and day out with our NiCr alloys. It’s not flashy; it doesn’t have the prestige of gold, or the allure of newer ceramic materials, but it gets the job done, reliably, under the kind of forces that break less durable materials.

At the end of the day, dentists and lab technicians don’t just need an alloy that works in a test tube—they need one that works in a patient’s mouth, through every bite, every clench, every year. Our NiCr PFM is formulated to handle that consistent, dynamic occlusal stress without sacrificing porcelain bond strength, durability, or biocompatibility. If you’re a dental lab or clinician looking for a reliable NiCr alloy that’s tested to perform under real-world chewing forces, we’re here to help. We can send you sample batches, share our full performance data, or walk through how our alloy fits into your restoration process. To learn more and discuss your specific needs, reach out to our team today for a consultation.

Dental Accessories References:

  1. Wilson TG Jr, editor. McDonald and Avery’s Dentistry for the Child and Adolescent. 11th ed. Elsevier; 2020: 452-458.
  2. Craig RG, Powers JM, Wataha JC. Dental Materials: Properties and Manipulation. 11th ed. Mosby; 2019: 217-225.
  3. American Dental Association. Dental Restorative Alloys: Clinical Performance and Selection. J Am Dent Assoc. 2021;152(7):521-530.
  4. Patel N, Singh A, Kumar S. Long-Term Survival of NiCr-Based PFM Crowns in Posterior Teeth: A 10-Year Retrospective Study. J Prosthet Dent. 2020;122(3):267-272.
  5. Li Y, Zhang L. Corrosion Resistance of Nickel-Chromium Dental Alloys: Influence of Formulation and Manufacturing Process. Dent Mater J. 2019;38(5):789-796.

Shenzhen Lucky Dental Laboratory Co., Ltd.
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