Final answer:
A porcelain fused to metal crown has porcelain on the outer surface to mimic the appearance of natural tooth enamel, providing strength and aesthetics.
Step-by-step explanation:
In dentistry, a porcelain fused to metal (PFM) crown is designed with the porcelain on the outermost surface that mimics the natural appearance of tooth enamel. The underlying metal provides the necessary strength and structure, while the enamel-colored glass, which is essentially powdered porcelain, is bonded to that metal substructure. The PFM crown is constructed in this way to provide a durable restoration that also has an aesthetically pleasing, tooth-like appearance. The porcelain, being a fine, hard, and translucent ceramic formed of materials like kaolin clay or porcelain stone, is always on the outer surface of the crown, which is the part exposed in the mouth and visible when a person smiles or speaks. This aligns with the primary goal of a dental crown, which is to restore the function of a damaged or decayed tooth while also recreating its natural look.