1. A computing device readable medium having executable instructions which can be executed by a processor to cause a computing device to perform a method, comprising: associating an abnormal tooth shape with a model tooth shape from a reference library of model tooth shapes; mapping a predefined dental reference from the model tooth shape onto at least a portion of the abnormal tooth shape; and adding a location of the predefined dental reference to the abnormal tooth shape based on the mapped predefined dental reference from the model tooth shape.