how strong are human teeth

Human teeth are very strong, with the enamel—the outer layer—being the hardest substance in the body. Tooth enamel is primarily composed of hydroxyapatite and ranks about 5 on the Mohs hardness scale, making it stronger than steel but slightly less hard than diamonds. Teeth can exert a biting force of up to 200 pounds (about 890 newtons) and can withstand pressures up to approximately 5600 pounds per square inch (psi). Structurally, teeth can endure forces up to 30,000 pounds in some comprehensive loading scenarios, although they remain vulnerable to damage from bacteria, acids, and wear since enamel cannot regenerate once damaged. More technically, the shear strength of human teeth varies between different types, with median shear strength around 39 MPa, influenced by the enamel and dentin integrity. Teeth fracture mainly through enamel cracks initiated by biting forces, with enamel thickness and tooth size being critical factors in their strength and fracture resistance. Despite their strength, teeth require proper care to maintain their integrity over time because damage to enamel is permanent.