Comparing a New Rating of Malocclusion to the PAR Index and to the Subjective Evaluation of Experienced Orthodontists

Abstract

Indices to assess malocclusion have been developed for either rating the 'severity of malocclusion' or for prioritizing a patient's need for orthodontic treatment. Most of these indices evaluate the malocclusion through examination of one or two of the following diagnostic records: dental casts, photographs, or clinical exam. However, no prior research had attempted to incorporate all of the above pretreatment orthodontic diagnostic records routinely taken for treatment evaluation. Pretreatment records (dental casts, intra-oral photographs, extra-oral photographs, panoramic radiograph, and a cephalogram, of sufficient quality to be reliably assessed) of 50 completed subjects treated at IUSD Graduate Orthodontic Clinic were evaluated. Subject criteria were a complete set of pretreatment orthodontic records, white non-Hispanic descent in the permanent dentition, absence of any craniofacial anomalies and known pathology. The 3M Unitek TM cephalometric protractor and electronic digital calipers accurate to the nearest tenth of a millimeter were used for measurements. Thirty-six measurements (11 cephalometric, 4 panoramic, 13 dental cast, and 8 photographic) were scored and combined into a total score that represents the new index. The peer assessment rating index (PAR Index) and a subjective ranking of 3 experienced orthodontists (each having more than 20 years of clinical orthodontic experience) were completed on all subjects for determining validity of the new index. All scoring methods were repeated on a subset of 10 random subjects to determine reliability. Statistical analysis showed significant correlations for the ability of the new index to detect severity of malocclusion. Also, the study showed a higher correlation for the new index in representing the experts' rankings than did the PAR index. It is the conclusion of this investigation that the new index is a valid index of malocclusion that more closely reflects experienced orthodontists rankings than the PAR index.