When should the shade/color of a dental crown be selected during the restorative appointment?

Crown shade selection should be performed at the very beginning of the appointment, before any tooth preparation, before local anesthesia (which can affect patient communication), and before rubber dam placement. This is important because: tooth preparation causes dehydration of enamel which lightens the tooth color artificially; rubber dam placement and the concentration on procedure can alter natural conditions; and natural light or standardized lighting conditions are needed for accurate shade matching. The tooth should be hydrated, and shade selection should be done in natural light or with a calibrated dental light. The shade guide should be moistened and compared to adjacent teeth.