Modern dental crowns are strong enough to handle everything your natural teeth can. The average human bite generates 120 to 160 pounds per square inch of force, and today’s crown materials exceed that threshold by a wide margin. How much stronger depends on the material your dentist uses, where in your mouth the crown goes, and whether you grind your teeth.
Strength by Material
Crown strength is measured by flexural strength, which is how much bending force a material can take before it cracks. The unit is megapascals (MPa), and higher numbers mean a tougher crown.
Zirconia is the strongest option available. Monolithic zirconia, milled from a single solid block, reaches about 1,000 MPa. That makes it nearly impossible to chip or crack under normal chewing forces, and it’s the go-to choice for back teeth that absorb the heaviest loads. Newer translucent zirconia formulas (used when appearance matters more) come in slightly lower, around 850 MPa, which is still far above what your jaw can produce.
Lithium disilicate (sold under the brand name e.max) is the most popular option for front teeth and visible areas. Manufacturers report biaxial strength above 700 MPa, though independent lab testing has measured values closer to 460 MPa. Real-world fatigue strength, which reflects how the material holds up under repeated stress rather than a single force, drops to around 215 MPa. That’s still more than adequate for front teeth but worth considering if you need a crown on a molar.
Porcelain-fused-to-metal (PFM) crowns use a metal shell coated in porcelain. The metal core is strong, but the porcelain layer can chip or delaminate over time. Gold and full-metal crowns sit in a category of their own. They’re not the hardest materials, but gold is ductile, meaning it flexes slightly under pressure instead of cracking. That quality makes gold crowns exceptionally durable despite modest raw strength numbers.
How Crowns Compare to Natural Teeth
Natural tooth enamel is hard but brittle. In wear testing, enamel lost 0.47 cubic millimeters of volume when abraded against zirconia, while gold and zirconia crowns each lost only 0.01 cubic millimeters under the same conditions. That’s a roughly 47-fold difference. Crowns don’t just match your natural teeth in durability; in pure wear resistance, the best materials outperform enamel.
The tradeoff is that extremely hard crown materials can wear down the opposing natural tooth they bite against. Zirconia’s hardness, for example, means the tooth on the other side of your bite absorbs more friction than it would against a gold crown or natural enamel. Your dentist may factor this in when choosing a material, especially if the opposing tooth is unrestored.
How Long Crowns Actually Last
Strength in a lab doesn’t always translate to longevity in your mouth. Crowns fail for reasons beyond raw material strength: decay at the margins, cement breakdown, root canal complications, and gum disease all play a role.
A large study tracking crowns placed in general dental practices in England and Wales found that metal crowns (including gold) had the longest survival at 68% after 10 years, while all-porcelain crowns had the shortest at 48%. Separate studies focused specifically on gold crowns reported much higher numbers: 91% to 97% survival at 10 to 11 years. The gap likely reflects differences in how well the crowns were made and placed, not just the material itself.
Zirconia and lithium disilicate are newer to widespread clinical use, so comparable long-term data is still building. Short-term studies are encouraging. In one three-year trial, both monolithic zirconia and lithium disilicate molar crowns showed survival rates above 95%, regardless of whether the patient was a teeth grinder.
Why Material Thickness Matters
A crown’s strength isn’t just about the material. It also depends on how thick the crown can be, which is determined by how much tooth structure your dentist removes during preparation.
Zirconia needs the least room to work with: only 0.8 to 1.2 millimeters of clearance on the biting surface. That means less of your natural tooth is drilled away, which preserves more healthy structure underneath. Full metal crowns are similarly conservative, needing just 0.8 to 1 millimeter.
Lithium disilicate requires more space, typically 1.5 to 2 millimeters on the biting surface, because thinner sections are more prone to fracture. PFM crowns need 1.5 to 2 millimeters on the visible side (to support the porcelain layer) and about 1 to 1.2 millimeters on the tongue side where only metal is present. If your tooth is already heavily broken down and there isn’t much structure left, these thickness requirements can influence which material is practical.
Crowns and Teeth Grinding
Bruxism is a significant risk factor for crown failure across nearly every material. The repeated, excessive forces generated during grinding or clenching, which can be several times higher than normal chewing, accelerate wear, cracking, and cement breakdown.
The exception is monolithic zirconia. Research consistently identifies it as the one indirect restoration that holds up well even in patients who grind. In a controlled study comparing grinders to non-grinders, monolithic zirconia crowns on molars showed a 95.2% survival rate in the bruxism group versus 95.8% in the non-bruxism group, a statistically insignificant difference. Lithium disilicate fared reasonably well too (96.3% survival among grinders), though its success rate, which accounts for complications short of outright failure, dropped to 81.5% compared to 95.2% in non-grinders.
If you grind your teeth heavily, monolithic zirconia on your back teeth combined with a night guard is the most protective combination. For front teeth where aesthetics matter, lithium disilicate remains a solid choice, but the night guard becomes even more important.
Solid vs. Layered Crowns
How a crown is constructed affects its real-world strength as much as the base material. A monolithic crown, milled from a single block of material with no additional layers, is the strongest configuration. A layered crown uses a strong core (usually zirconia) with hand-applied porcelain on top for a more natural appearance. The zirconia core retains its strength at 900 to 1,000 MPa, but the porcelain coating introduces a weak point where chipping or delamination can occur.
This is the same vulnerability that affects PFM crowns. The metal underneath is tough, but the porcelain veneer is the part that breaks. If maximum strength is your priority, a monolithic design in either zirconia or lithium disilicate will outperform any layered version of the same material.