Functional appliance treatment assessed using the PAR Index

The aims of this study were, first, to determine in children with Class II, division 1 malocclusions treated with functional appliances if, according to the Peer Assessment Rating (PAR) Index, lower incisor proclination affects the assessment of treatment outcome; and, second, to evaluate the effectiveness of such treatment before and after adjustment for any lower incisor proclination.

Fifty-one children (32M, 19F; age and gender matched; 10 to 13 years) were randomly assigned to either an untreated group, one treated with Fränkel function regulators or one treated with Harvold activators. Study casts were assessed at the start, and after 6, 12, and 18 months of treatment/observation. The inclination of the upper and lower incisors was measured on lateral cephalometric radiographs taken at the start and 18 months later. There was wide variation in treatment response. The PAR scores decreased by more than 30% in 33% of the Fränkel group and by 75% in the Harvold group. When the score was adjusted to remove the effects of lower incisor proclination on the overjet, the treatment outcomes were “worse/no different” in 66% and “improved” in 33%, in both groups. It was concluded that functional appliances be used only on selected cases.