Classification of maxillary dental arches by correlation and principal component analyses

Abstract

Using 62 plaster dental models, we determined midpoints of the incisal ridge of the incisors (I1_R, I1_L, I2_R & I2_L), cusp tips of the canines (C_R & C_L), summits of buccal cusps of the premolars (P1_R, P1_L, P2_R & P2_L), summits of mesiobuccal cusps of the molars (M1_R, M1_L, M2_R & M2_L) and the midpoint A of line (I1_R-I1_L). Point B is defined as the intersection of the vertical line from point A with the line (M2_R-M2_L). Point E is the intersection of (A-B) with (C_R-C_L). We evaluated protrusion of the canines, curvature of the anterior teeth, length-to-width ratio of the dental arch, and degree of roundness of the arch. Six items were summarized into three essential principal components. We also determined the relation of the contour and position of line (P1-P2-M1-M2) to line (P1-M2). The results indicated that 60% of the maxillary dentitions had round-square arches; square arches showed a small value for protrusion of the canines; round arches were characteristic by a small degree of arch roundness; and round V-shaped arches had large values for curvature of the anterior teeth.