Maxillary and Mandibular Dents

The Maxillary Central Incissor

The tooth is the largest and broadest of the incisors. The crown is relatively square when viewed from the labial aspect and is about the same length as the root. When the root is viewed from the labial aspect it is elongated cone that is triangular in cross section. The mesial aspect of the root is the longest side of the triangle, a feature that is very useful for determining which side the root is from.

Viewed from the labial aspect, the crown is somewhat square with the incisal edge slightly rounded at each end although this edge may be worn straight. The mesial angle of this incisal edge (mesio-incisal) also rounded is sharper than the more rounded disto-incisal angle. This feature often helps with identifying left from right provided that the incisal angles have not been worn away.

The palatal surface of the crown is more triangular in outline than the squarish labial surface. There is a pronounced cingulum which is slightly off-centre displaced towards the distal. This feature of the central incisor along with the cross-section of the root is a good way of determining which side of the mouth it comes from.

The palatal surface also shows marginal ridges when these ridges stand out clearly the incisors are referred to as shovel-shaped.

The Mandibular Incisors

It is difficult to distinguish mandibular central incisors ftom mandibular lateral ones unless they are from the same person even then it can be challenging. The lateral incisor is wider at the incisal edge than the central one and when viewed from the incisal aspect the distal part of the incisal edge curves towards the lingual one. The root of the lateral is longer than the root of the centre maqndibular incisor.

The mandibular incisors are long and narrow, the crown being very narrow in relation to its length. The roots of these teeth are roughly oval in section and usually are flattened on the mesial and distant surfaces. Often these flattened surfaces form shallow grooves giving the root a cross section.

The mandibular incisors are in general are long and narrow, the crown being very narrow in relation to its length. The roots of these teeth are roughly oval in section and usually are flattened on the mesial and distal surfaces. Often these flattened surfaces form shallow grooves giving the root a cross section.

The mandibular incisors are, in general, much more sharply angular than their maxillary counterparts. When the tooth is viewed from the labial aspect (or the lingual) the disto-incisal angle is more rounded than the mesio-incisal angle.

The lingual surface of the crown is almost triangular, with the apex of the triangular forming a pronounced cingulum.

The Canines

The two canines are prominent, strong teeth situated at the corners of the mouth. Their function is to “tear” food. Their main feature of identification is the crown which has a distinctive pentagonal labial surface and two incisal edges which join to form a cusp, however, this often may be worn away.

When viewed from the labial aspect the crown of the upper canine is broader mesio-distally than the crown of the lower one. The upper canine also has more distinct ridges and markings that the lower one. The root of the lower canine is flattened and much wider labio-lingually than mesio-distally whereas the root of the upper canine is oval in cross section.

When the canines have been worn down the pattern is for tooth tissue to be worn away from the palatal aspect of the upper canine and the labial aspect of the lower one. Frequently worn lower canines are confused with lateral incisors and a useful tip is to observe the incisal edge. The incisors will show a strip of exposed dentine whereas in canines the exposed dentine will be diamond shaped. The palatal surfaces will also show marginal ridges that merge with a prominent cingulum.