Schematic Drawing of Central Incisor

Appearance of the table (occlusal) surface at different stages of wear.
1. Shortly after eruption its breadth (transverse, long diameter) marked by a-b, its thickness (short diameter) c-d.
2. Shows the table surface as it appears at the age of six years, the breadth a-b, begins to decrease,
and the thickness, c-d, increases slightly; the tooth appears oval.
3. Shows a round surface of nine to twelve years. The two diameters become equal.
4. Shows a triangular surface
of fourteen to seventeen years.
The long diameter, c-d, in the
labiolingual direction.
5. Shows surface of animal over twenty in which breadth, a-b,
measures only half as much as thickness, c-d.
6. Depicts exposed incisor.