Full diagnostic records are a medical-legal necessity to diagnose, treatment plan, monitor clinical progress, and evaluate outcome. "We (orthodontists) have been concerned with the anatomical relations of the teeth, the relation of the mandible to the maxilla, the relation of the teeth in the entire facial component, but this is not enough. We must enlarge our scope of knowledge and responsibilities to be equally concerned and competent as physiological orthodontists." (Thompson) Treatment outcome distinction is made between static evaluation of records and "plaster models on the table", and functional evaluation of the finished case. Most occlusal "chewing" function occurs with the first molar and premolar teeth. It is reported that 90% of chewing function is first molar and bicuspid region. Physiologically oriented orthodontists must consider: soft tissue profile and facial esthetics, incisal misguidance (interference), narrow or constricted maxilla, underdeveloped or retruded maxilla, overdeveloped or prognathic mandible (Class III actual of effective condition relative to maxilla), crowding or displacement of teeth, and (TMJ) temporomandibular joints must be considered. Second molars are the common cause of working balancing, and protrusive occlusal disturbances. The mesial distal width of second molar teeth and premolar teeth is not significantly different. Second molar replacement is a viable option for many patients (not all) undergoing orthopedic and orthodontic treatment who require removal of teeth for treatment purposes. The most important teeth for chewing are first molar to first molar teeth.