Which statement best describes a factor that increases porcelain chipping risk in metal-ceramic restorations?

• A. Adequate metal support
• B. Thin porcelain
• C. Balanced occlusion
• D. Strong bonding

Answer: (B)

Thin porcelain increases the risk of chipping because porcelain is a brittle material whose strength is highly dependent on its thickness. When the porcelain layer is too thin, it cannot adequately resist the bending and tensile stresses generated during chewing and biting. Those stresses concentrate at the surface and at the porcelain–metal interface, so a small flaw can crack and propagate, leading to chipping. In contrast, adequate metal support helps share the load and reduce flexure, balanced occlusion minimizes peak forces, and strong bonding mainly helps prevent debonding rather than fracture—so they don’t inherently raise the risk of chipping. The key idea is that thinning the porcelain weakens its fracture resistance, making chipping more likely.