A crown (also known as a cap) is a cover that is placed over a tooth. It restores the tooth to a more ideal shape or size, and can improve its function and strength. Additionally, crowns can improve the esthetics of a tooth, especially if it is a front tooth. Typically crowns are made of porcelain, metal, or a combination of the two materials, with the porcelain coating the outside of the metal.
Veneers are similar to crowns, but do not cover the tooth on all surfaces. Typically, a veneer will be bonded to the front (visible surface) of a tooth, but commonly wraps very slightly over the edge of a front tooth, and extends in between the teeth so that its margins (edges) are not showing. Veneers are almost universally made to improve esthetics, but also can be used to treat chipped or worn teeth. They are always made from a type of porcelain to mimic the esthetics of enamel.
Since crowns and veneers perform similar functions, are often made of the same materials, and can be cemented with the same types of cements, they are typically very comparable in cost and in the length of the appointment time needed. In my office, I use both options, depending on many factors. In reality, though, there is often little difference between the two options, especially if the veneers are the type which wrap around the sides and edges. Both are wonderful options to restore or create an amazing smile.