ASSESSMENT OF BIOLOGICAL CHANGES IN A NONORTHODONTIC SAMPLE USING THEPAR INDEX

The aim of the present study was to assess the effect of normal growth and development on the Peer Assessment Rating index between 12 and 22 years of age. The sample consisted of 49 nonorthodontic subjects (24 male and 25 females) from the Nijmegen Growth Study. The mean age at t he first observation was 12.2 +/- 0.7 years and at the second observat ion 22.1 +/- 0.6 years, The dental casts at these ages were scored wit h the Peer Assessment Rating index. The influence of the Angle classif ication and the treatment need on changes over time in the Peer Assess ment Rating score were evaluated. The mean changes in the PAR scores o ver time between cases that have more than 30% improvement to those th at have less than 30% improvement were calculated. The results indicat e that there were no significant differences between the mean Peer Ass essment Rating score at 12 years of age (12.20 +/- 0.91) and at 22 yea rs of age (12.45 +/- 1.28), but there were relevant differences in ind ividual cases. The changes were irrespective of the Angle classificati on or the treatment need. Changes over time in the weighted Peer Asses sment Rating score were mainly correlated to changes in the anterior c rossbite and the overjet, This correlation may be influenced, however, by the applied weighting factor for those occlusal traits.