LEVELING OF THE PERMANENT INCISORS. 93 



side, the obliquity of the teeth is greater, and, as the inferior 

 corner teeth now commence to wear by their posterior borders, 

 their tables become elongated and correspond to the tables of 

 the superior corner teeth in size, so that the notches of the latter 

 become less marked. The interspaces between the teeth become 

 more marked and the gum commences to retract from the 

 crowns, giving a square cut-off appearance. The tables become 

 more convex on their posterior borders, and the cups, which 

 continually approach the posterior borders of the teeth, in the 

 pincher teeth become convex behind. In front of them, half-way 

 to the anterior border of the teeth, a transversely elongated dark- 

 yellow line appears. This is the dental star, brought into view 

 by the uncovering of the calcified dental pulp. If the structure 

 and formation of the incisive teeth are remembered, the exact 

 value of the dental star will be better appreciated. In the 

 virgin tooth the upper extremity is hollowed by the cup, and 

 the dental pulp occupies the space between the anterior face of 

 the cup and the anterior face of the tooth itself. But we have 

 seen that the cup, pointing downward, also inclines toward the 

 posterior border of the tooth. At eight years the cup is at 

 the division of the posterior and middle thirds of the table of the 

 tooth, and the dental pulp is found on the line between the 

 middle and anterior thirds. The transverse extent of the dental 

 star is much less in the intermediate and corner teeth than it is 

 in the pincher teeth. 



