Objective: Using PAR index to evaluate severe malocclusion, pre- and post- treatment. Subject and method: A retrospective, prospective, cross-sectional descriptive study in 62 patients (with study models of pre- and post- treatment) from 2010 to 2013 at Department of Odontology, No.108 Military Central Hospital. Result: Good results (91.9 percent) with 57 patients, improved results (8.1 percent) with 5 patients and there were no patients had bad results. The mean of PAR index pre- and post-treatment was 5.2. Conclusion: The PAR index to evaluate the outcome of orthodontic treatment have high reliability
result was determined by natural numeral and it was one of compelled standards to evaluate the success of occlusion.