352 



BUREAU OF AMERICAN ETHNOLOGY 



[Bull. 182 



degree attrition, and third-degree wear was usual by 45 years of age. 

 Decay and loss are relatively rare, and relatively few teeth in each 

 dentition are affected. In this pattern of wear, as the crowns of the 

 teeth are worn down, the distance from the enamel margin to the 

 alveolar crest gradually increases. This is, in effect, a continued 

 physiological eruption of the teeth, partially compensating for the 

 shortening of the teeth, Wlien third- or fourth-degree wear is at- 

 tained, attrition takes place more rapidly than secondary dentine can 

 be formed, the unprotected pulp becomes infected and periapical 

 lesions form, often with draining fistulae, followed by destruction of 

 the alveoli and loss of the teeth. As periapical infection proceeds, 

 cavities appear in the crowns of the teeth, and eventually the 

 affected teeth are lost. Spaces appear between the teeth as the crowns 

 are worn down so that contact between adjacent teeth is lost, or 

 after slight migrations of teeth in the arch. When food becomes 

 impacted in these spaces interproximal caries follows. Tartar for- 

 mation is usually slight, and causes little alveolar resorption. 



Table 1. — Age and wear of teeth in adults 



Table 2. — Wear, decay, and loss of teeth during life in children and adults 



' One fractured upper second molar. 



In contrast to the relatively healthy teeth of the ToUifero crania, 

 the teeth of the Clarksvllle crania are in extremely poor condition. 

 First- or second-degree wear is the rule, even in older people, with 

 caries appearing in the crowns of both deciduous and permanent teeth, 



