The margin
A quality crown fits the tooth with a closed margin, prepared and checked under magnification. A poor one leaves a gap that traps plaque and decays the tooth underneath.
The material and the laboratory
Named ceramics chosen for the bite, layered by a skilled technician from photographs and the design. Low-cost crowns are often opaque, poorly matched and made from unspecified materials.
The bite
A quality crown is balanced in the bite at fitting; a high crown fractures or overloads the root. The cheaper crown usually costs more, because it is paid for twice.
