SIX YEARS. 



The cutting surface of the posterior border ot the corner incisors 

 is worn flat with the remainder of the tooth ; its central enamel, 

 forming a complete ring. The tables of the front incisors tend to 

 assume an oval form. Those of the lower front incisors are, as a 

 rule, worn level ; the dental cavity having disappeared out of 

 them ; and, in some cases, out of the lower middle incisors. The 

 front incisors, viewed from the front, are slightly whiter than at 

 five years old, on account of their beginning to lose their coating of 

 cement. In this example, the upper corner incisors are irregularly 

 formed, being fissured on their inner side. 



