Two reliable and valid occlusal indices have been developed to assess treatment need (Index of Treatment Need, IOTN) and the standard of treatment (The PAR Index, Peer Assessment Rating). The IOTN assesses both dental aesthetics and dental health need. The PAR index provides a single summary score for the overall alignment and occlusion. The difference between the pre- and post-treatment scores reflects the degree of improvement and the success of orthodontic intervention and active treatment. Several practical uses of the indices are described: the estimation of treatment need in an unselected and a referred population and the assessment of the standard of treatment in the Hospital and General Dental Services. It has been suggested that the use of the occlusal indices would offer several advantages: (1) uniformity in prescribing patterns, (2) safeguards for the patient, (3) patient counselling and (4) monitoring and promoting standards.