Instead, canine cusp tip
and the tip of the mesiopalatal cusp of the first molar were used.
Inter-1/4urst premolar width: Measurements were made between the buccal cusp tips
of right and left 1/4urst premolars.
The depth of curve of Spee was measured with divider placed between the deepest cusp tip
* Arch width was measured as the distance from the cusp tip
of one tooth to the cusp tip
of the contralateral tooth, the inter-incisor width was measured from the distal contact point of the lateral incisor on one side to the distal contact point of the lateral incisor on the contralateral side [Bishara et al., 1997] (Fig 1).
It is the measured distance between the right and left first molars distobuccal cusp tips
. D--the arch depth.
The depth of the von spee's curve was calculated on lateral cephalograms as perpendicular distance from tip of lower central incisor to the mandibular plane (L1-MP), distobuccal cusp tip
of the lower second molar (M7-MP) to the mandibular plane, the deepest point of the von spee's curve to the mandibular plane (S-MP), and proportioned with each other.
Plane or swale defects are characterized as an irregular sloping around the cusp tips
of cheek teeth and the incisor edges of anterior teeth.
with a Vernier Caliper as the perpendicular distance between the deepest cusp tip
and a flat plane, that was laid on top of the mandibular dental cast touching the incisal edges of the central incisors and the distal cusp tips
of the most posterior teeth in the lower arch as done by Braun et al5 and Braun and Schmidt.16 The measurement was made on the right and left side of the dental arch and the mean value of these two measurements were used as depth of curve of Spee.
Clinically, the COS is measured by placing a flat plane touching the incisal edges anteriorly and distal marginal ridges of the most posterior teeth.18 This is in contrast to prosthetic dentistry where the curve begins from cusp tip
of mandibular canine and follows the buccal cusp tips
of posterior teeth.19 In our study mandibular incisors were used as the anterior limit of the curve as to determine the contribution of anterior vertical eruption to its development.
The teeth were mounted vertically in acrylic resin to 2 mm below the CEJ, approximately the level of the alveolar bone in a healthy tooth, such that the cusp tips
aligned in the same plane to ensure a more equal distribution of the load during testing.
The following reference points and planes on lateral cephalograms were used: L1, the incisal tip of the mandibular central incisor; M7, the distobuccal cusp tip
of the mandibular permanent second molar; mandibular plane (MP), the line between gonion and gnathion; L1-MP, the perpendicular distance from the tip of L1 to the mandibular plane; M7-MP, the perpendicular distance from the distobuccal cusp tip
of M7 to the mandibular plane; and S-MP, the perpendicular distance from the deepest point of the COS to the mandibular plane (Fig 1).10 The depth of the COS was measured on models by method advocated by Veli et al10 in which horizontal reference plane comprising a line between the central incisors and the distobuccal cusp tips
of the mandibular second molars was constructed.
Maxillary Intercanine width (UC-C): Distance between the cusp tips
of right and left maxillary permanent canines.
Mandibular Intercanine width (LC-C): Distance between the cusp tips
of right and left mandibular permanent canines.
2 Maxillary Interpremolar width (UP-P): Distance between buccal cusp tips
of right and left maxillary permanent first premolars.