The Validity of Articulare for Measurement of Mandibular Length

Abstract

Mandibular length is commonly defined as the linear distance between condylion and pogonion. The use of condylion in mandibular length and growth measurements, however, is technically difficult because condylion is often obscured in the standard closed-mouth lateral cephalogram. As a result, many studies have utilized articulare as a substitute for condylion because it is readily identifiable in most lateral cephalometric films and is reasonably close in proximity to condylion. To date, very few studies have examined the validity of articulare and the literature provides conflicting reports. The present study examines the validity of articulare in mandibular length measurements by taking three cephalograms on each of 60 consecutive patients: 1) closed-mouth with the patient in habitual occlusion, 2) closed-mouth lateral with the patient in centric relation, and 3) an open-mouth lateral cephalogram. The linear distances (mm) of Ar-Pog, Ar-Go, and Go-Pog were measured on the two closed-mouth cephalograms and compared with each other as well as the linear distances of Co-Pog, Co-Go, and Go-Pog measured from the open mouth cephalogram on each individual. Product-moment correlation coefficients were used to measure the linear associations between the mandibular measurements from the three techniques. Repeated measures analysis of variance were also fit to estimate the correlations between the three measurements adjusted for age and gender. The results of this study show that measurements taken from both closed-mouthed techniques agreed extremely well (ICC=.99). In addition, measurements from both closed-mouth techniques correlated very highly with corresponding measurements taken with the open-mouth technique (ICC=.94). This data suggests that measurements taken from Ar correlate very well with measurements taken from Co and that this correlation is not dependent on whether the patient is positioned in habitual occlusion or centric relation.