tooth morphology and occlusion
Tooth morphology
Table 3.1 gives definitions of terms used for the descriptions of tooth form.
Term | Definition |
---|---|
Crown | Clinical crown — that portion of a tooth visible in the oral cavity |
Anatomical crown — that portion of a tooth covered with enamel | |
Root | Clinical root — that portion of a tooth lying within the alveolus |
Anatomical root — that portion of a tooth covered by cementum | |
Cervical margin | The junction of the anatomical crown and the anatomical root |
Occlusal surface | The biting surface of a posterior tooth (molar or premolar) |
Cusp | A pronounced elevation on the occlusal surface of a tooth |
Incisal margin | The cutting edge of anterior teeth, analogous to the occlusal surface of the posterior teeth |
Tubercle | A small elevation on the crown |
Cingulum | A bulbous convexity near the cervical region of a tooth |
Ridge | A linear elevation on the surface of a tooth |
Marginal ridge | A ridge at the mesial or distal edge of the occlusal surface of posterior teeth. Some anterior teeth have equivalent ridges |
Fissure | A long cleft between cusps or ridges |
Fossa | A rounded depression in a surface of a tooth |
Buccal | Towards or adjacent to the cheek. The term buccal surface is reserved for that surface of a premolar or molar which is positioned immediately adjacent to the cheek |
Labial | Towards or adjacent to the lips. The term labial surface is reserved for that surface of an incisor or canine which is positioned immediately adjacent to the lips |
Palatal | Towards or adjacent to the palate. The term palatal surface is reserved for that surface of a maxillary tooth which is positioned immediately adjacent to the palate |
Lingual | Towards or adjacent to the tongue. The term lingual surface is reserved for that surface of a mandibular tooth which lies immediately adjacent to the tongue |
Mesial | Towards the median. The mesial surface is that surface which faces towards the median line following the curve of the dental arch |
Distal | Away from the median. The distal surface is that surface which faces away from the median line following the curve of the dental arch |
Dental notation
Differences between teeth of the deciduous and permanent dentitions
The roots of deciduous and permanent teeth are distinguished essentially by:
The pulps of deciduous and permanent teeth are distinguished essentially by:
Incisors
Maxillary first (central) permanent incisor
Maxillary second (lateral) permanent incisor
Mandibular first (central) permanent incisor
The mandibular first (central) permanent incisor has a bilaterally symmetrical triangular shape. In the newly erupted tooth, three mammelons are usually present. The incisal margin is at right angles to a line bisecting the tooth labiolingually. The mesio-incisal and disto-incisal angles are sharp and the mesial and distal surfaces are approximately at right angles to the incisal margin. The profiles of the mesial and distal surfaces appear very similar, being convex in their incisal thirds and relatively flattened in the middle and cervical thirds. The lingual cingulum and mesial and distal marginal ridges appear less distinct than those of the maxillary incisors. The cervical margins on the labial and lingual surfaces show their maximum convexities midway between the mesial and distal borders of the root. The cervical margin on the distal surface is less curved than that on the mesial surface. The root is narrow and conical, though flattened mesiodistally, and is frequently grooved on the mesial and distal surfaces (the distal groove being more marked).
Mandibular second (lateral) permanent incisor
Maxillary first (central) deciduous incisor
Maxillary second (lateral) deciduous incisor
Mandibular first (central) deciduous incisor
Mandibular second (lateral) deciduous incisor
Canines
Maxillary permanent canine
Mandibular permanent canine
Maxillary deciduous canine
Mandibular deciduous canine
Premolars
Maxillary first premolar
Maxillary second premolar
Mandibular first premolar
Mandibular second premolar
Molars
Maxillary first permanent molar
Maxillary second permanent molar
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