title: The reproducibility and the validity of landmarks for the antero-inferior part of the maxilla in radiographic cephalometry.
abstract: Two possible landmarks, C1 and C2, were evaluated as alternatives to the A point (subspinale), in lateral radiographic cephalometry. The landmarks were determined on tracings of 25 straight lateral radiographs. Horizontal and vertical coordinates were recorded for C1 and C2, and also for point A, and the incisor edge and apex. The reproducibilities of the landmarks were determined by statistical analyses of the differences between landmark determinations on repeated tracings. Regression analyses were used to evaluate the validity of measurements on C1 and C2 in relation to corresponding measurements on the A point. In addition, the influences of upper incisor inclinations and of alveolar process inclinations on validity were investigated by regression analyses and analytical geometry, respectively. The reproducibility of all landmarks including C1 and C2 was high (correlation coefficients above 0.985). Both C1 and C2 were strongly correlated with point A (adjusted R2 values from 82 to 85 per cent). The inclination of the lingual aspect of the alveolar process may change from an alteration of the incisor inclination. When this happens, the positional change of C2 horizontally is smaller than the change of C1. Therefore, C2 appears to be the more valid landmark for horizontal measurements. The designation suggested for this landmark is C.
authors.affiliation: Department of Orthodontics, University of Umeå, Sweden.
authors.forename: L A
authors.initials: LA
authors.lastname: Eliasson
authors.forename: J
authors.initials: J
authors.lastname: Gelfgren
mesh_terms: D000539:Alveolar Process / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D002508:Cephalometry / Q000706:statistics & numerical data*; D006801:Humans; D007180:Incisor / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008433:Mathematics; D008437:Maxilla / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D009295:Nasal Bone / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D010159:Palate / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D011859:Radiography; D012044:Regression Analysis; D015203:Reproducibility of Results