Permanent incisors

Why this matters

Incisors are the teeth your patient shows you before they say a word, the teeth trauma reaches first, and the teeth whose anatomy decides whether a papilla fills the space between them. They are also the teeth students most often get wrong in the one way that matters: not naming the tooth type, but naming the SIDE. In a worldwide survey of dentists identifying 3D tooth models, the commonest error category was region - which side of the mouth the tooth came from.

The big picture

Four teeth built on one wedge-shaped plan, separated by a single asymmetry - a sharper mesial corner and a rounder distal one - that the mandibular central alone abandons. Below the crown the same plan gives a flattened root and a canal that is oval far more often than round, which is where incisor anatomy turns clinical.

The 15 cards in this lesson

1. 01Four incisors run one plan, and the distal corner is what gives you the side
2. 02The maxillary central incisor: one plate, five aspects, every landmark keyed
3. 03The maxillary lateral incisor is the same tooth with the variation turned up
4. 04The mandibular incisors: the pair you cannot side by shape, and the pair with grooved roots
5. 05Separate the four incisors on shape; the measurements overlap and the shapes do not
6. 06A crown length is a landmark before it is a number
7. 07A small crown does not mean a short root - the lateral incisor's root is the longer one in both arches
8. 08Numbers that will not add up, and the error bar you cannot see on a radiograph
9. 09Incisors touch over an area, and whether the papilla fills the gap is a measurement
10. 10Mamelons and the shovel: which parts of incisor surface form have actually been counted
11. 11Clinical alert — in the lesson
12. 12Three pulp horns under three lobes, and what age does to the chamber
13. 13More than one canal is ordinary in a mandibular incisor, and the second one is buccal or lingual
14. 14Four series, two classifications, and one range you can honestly quote
15. 15What incisors are for: the lowest force and the finest touch in the arch, and they arrive first

You have got it when

You can: name every landmark on an incisor crown and root and say which surface it is on; side a maxillary incisor from its incisal angles; say why a published crown length is meaningless without its landmark; say which incisor root is longest and which is shortest, with the series behind each; say how often a mandibular incisor carries more than one canal and why a straight-on periapical under-reads it; and name…