Table 1 Skeletal and dentoalveolar measurements

Anterior alveolar ridge height

Measured in millimeters from the bony ridge of upper incisors by drawing a straight line parallel to the midsagittal plane till the floor of the nostrils on the side of impacted canine and side without impaction (Fig. 1)

Anterior dentoalveolar height

Measured in millimeters from the incisal edge of upper incisors by drawing a straight line parallel to the midsagittal plane till floor of the nostrils on side of impacted canine and side without impaction (Fig. 2)

Nasal cavity width

Measured in millimeters from the anterior nasal spine to the lateral wall of the nasal base on the side of impacted canine and the canine without impaction (Fig. 3)

Basal lateral width

Measured in millimeters from the anterior nasal spine to the outermost dentoalveolar rim on the side of impacted canine and the canine without impaction (Fig. 4)

Lateral angulation of long axis of the incisors with respect to the nasal horizontal plane

Value of the external angle of the longitudinal axis of the central and lateral incisors of both quadrants with respect to the tangent of the nostril floor (Fig. 5)

Lateral angulation of long axis of canines with respect to the nasal horizontal plane

Value of the external angle of the longitudinal axis of the impacted canine and which has no impaction with respect to the tangent of the nostril floor (Fig. 6)

Premolar width

Distance in millimeters from the middle palatine raphe to proximal alveolar bone crest between the canine (deciduous or permanent) and first premolar on each side, measured in the axial cut at bone crest level (Fig. 7)