The unit of measurement in the figure is millimeters. The curvatures on the labial , buccal, and lingual surfaces of all maxillary teeth and on the buccal surfaces of mandibular posterior teeth are rather uniform; the average curvature, as mentioned before, is about 0.
Note that the graph tends to run somewhat parallel to this line. The mandibular canines may show a little more curvature than central and lateral incisors. They are based on cases having upper central incisors with crowns 10. Careless treatment can cause breaks in the attachment, making the tooth liable to further physical or pathological injury. Compare the graph of cervical curvatures with a line drawn through the center of contact areas.
Figure 5-25 Schematic drawing of the crowns of maxillary and mandibular teeth with associated graphs of the average extent of curvatures of the cervical line mesially and distally.
A comparison of the curvatures of the CEJ mesially and distally on the teeth is therefore in order. Normal attachment follows the curvature of the CEJ if the teeth are in normal alignment and contact. The epithelial attachment seals the soft tissue to the tooth.
Improper usage of impression materials must also be avoided. This does not mean that the CEJ and the epithelial attachment are at the same level, but it does mean that they tend to follow the same curvature, even though the epithelial attachment may be higher on the crown on its enamel surface Figure 5-24.
The average premolar or molar has a curvature mesially of only 1 mm or less, with no curvature or even a minus curvature distally Figure 5-27. Occasionally maxillary posterior teeth have similar curvatures on the lingual aspect.
Mandibular anterior teeth show less curvature on the crown above the cervical line than any of the other teeth. The height of attachment is dependent on the height of the contact areas of the two teeth creating the interproximal space.Simplifying Posterior Dental Anatomy
Previous post: Figure 5-24 Curvatures of the cervical line cementoenamel junction mesially and distally on the maxillary central incisor, demonstrating the points of measurement in determining the relation between the curvatures of the cervical line mesially and distally. The six anterior teeth , both maxillary and mandibular, when compared with posteriors, exhibit the greatest curvature. B, Mandibular teeth.
The teeth can be injured by careless probing during clinical examination, by improper scaling during prophylactic treatment, by tooth preparation techniques in operative procedures, and so forth. The curvature of the cervical line of most teeth CEJ is approximately 1 mm less distally than mesially.