Tooth Identification

General Rules of Tooth Identification

The curvature of the CEJ is usually about 1 mm less on the distal surface than on the mesial.

Tooth roots do not always curve; however, if they do curve, they usually curve distally, especially at the apex of the root. It is not uncommon, however, for the root to curve toward mesially.

The distal incisal edges of anterior teeth are more rounded than the mesial incisal edges.

Mandibular anterior teeth tend to wear on their labial incisal edges, whereas maxillary teeth wear on the lingual incisal edges. Unless a person has a class III occlusion, the maxillary teeth are facial to the mandibular teeth.

Permanent molars are generally smaller in height and have fewer cusps the more posteriorly they are positioned.

Permanent molars tend to have more secondary and tertiary anatomy the more posterior they are positioned. Secondary anatomy consists of extra grooves and pits in addition to the main primary developmental anatomy. Tertiary anatomy refers to the extremely shallow and even more numerous grooves, pits and lines that third molars have, giving them a wrinkled appearance.

The roots of molars tend to be shorter and closer together the more posterior the molars are positioned, and the roots are often fused into one.

The more posterior the molars are positioned, then the more variation of the anatomy is evident. Third molars are more wrinkled and unpredictable in shape than second or first molars.

Anterior

Maxillary

Central

These incisors are the largest and most prominent incisors. The distoincisal is more rounded than the mesioincisal angle. The lingual surface has a prominent cingulum, broad lingual fossa, and distinct marginal ridges. The pulp cavity is one large single chamber and root canal.

Number of roots – 1 Number of pulp horns – 3 Number of development lobes - 4

Lateral

The lingual anatomical features are similar to those of the central incisors but are more highly developed and have more prominent marginal ridges and deeper lingual fossae. Lateral incisors are more likely to have a lingual pit. The cingulum may be smaller, almost absent. The labial surface resembles that of a central incisor except that the labial surface is more convex. The crown-root ratio is less than in a central incisor because the crown is usually smaller, whereas the root is almost as long. In all other ways the lateral incisors appear as a smaller, more rounded versions of the central incisors.

Number of roots – 1 Number of pulp horns – 1 to 3 Number of developmental lobes - 4

Canine

The maxillary canines are the longest teeth in the mouth. They have a single cusp with mesial and distal ridges forming an incisal edge. A prominent facial ridge is off-center toward the mesial. Cingulum is prominent. The prominent mesiofacial lobe forms the lingual ridge of the cusp. The lingual ridge divides the mesial and distal fossae. The distofacial ridge is longer and more rounded than the mesiofacial.

Number of roots – 1 Number of pulp horns – 1 Number of cusps – 1 Number of developmental lobes - 4

Anterior

Mandibular

Central

The distoincisal and mesioincisal angles are nearly identical. The lingual surface is shallow, with no prominent features. The crown is wider faciolingually and mesiodistally. The root is oval shaped in cross section. The incisal edge shows wear on the facioincisal edge. From a proximal view the incisal edge appears to be tilted toward the lingual side.

Number of roots – 1 Number of pulp horns – 3 Number of developmental lobes - 4

Lateral

The crown is similar to that of the mandibular central incisors. The distal lobe is more highly developed than the mesial. The distal incisal ridge angles toward the lingual as if rotating on the root axis. The crown and the root are slightly larger than those of the central incisors.

Number of roots – 1 Number of pulp horns – 3 Number of developmental lobes - 4

Canines

The crown is similar to the crown of the maxillry canines but narrower and smoother. It has less prominent lingual features. From a proximal view, the cusp tip is inclined to the lingual. From an incisal view, the distal end of the incisal edge is rotated to the lingual. They have the longest root in the mandibular arch, with longitudeinal grooves on the root.

Number of roots – 1 or 2 Number of pulp horns – 1 Number of cusps – 1 Number of developmental lobes - 4