PAR scores and age differences between siblings initiating orthodontic treatment

One of the most popular indexes used in orthodontics is the Peer Assessment Rating (PAR) index. Objectives: to find whether there are differences in the PAR index and age of treatment commence between siblings. Materials and Methods: Sixty study models of 30 pairs of siblings, mean age of 12.2 + 1.6 years representing variety of malocclusions were randomly selected from our archive in the IDF orthodontic department. All models were analyzed and scored twice by the same resident (PBH) using the original PAR index, and verified by a specialist (SG). The mean of the examiners score was calculated for each cast. 5 different scores were calculated: The original PAR index, The British modification index, the American modification, the American treatment and American severity Par indexes. Results: The age of the first sibling at the initial of orthodontic treatment was 11.4+1.4 years while the age of the second was 13.1+1.4. This difference was with statistical significance (P<0.001). There were no statistical significance differences between the siblings in all the 5 indices that were analyzed, however the PAR index of the first sibling was lower than the PAR score of the second one. Conclusion: First siblings start treatment at a younger age, although their PAR index tends to be smaller.