The PAR index have been developed to provide a single summary score for all the occlusal anomalies which may be found in a malocclusion. The difference in scores between the pre-and post-treatment cases reflects the degree of improvement and, therefore the success of treatment. The index was used in this study to assess treatment outcomes in 20 extraction and 20 non extraction class I and II cases. Both groups showed good treatment outcomes however the percentage reduction in the PAR scores were higher in the non extraction group. The pretreatment PAR scores were significantly higher in the extraction group indicating more severe malocclusion at the start of treatment.