THE TEETH 



87 



The incisors. — The central maxillary incisor is very much larger than the 

 lateral, the crown is somewhat oblong in outline, its length exceeding the breadth. 

 The median is longer than the distal border. The labial surface is convex, the 

 hngual concave, and terminates near the gum in a low eminence, the basal ridge 

 or cingulum. In recently erupted teeth, the cutting edge is elevated into three 

 ismall (usiis; these soon wear down and leave a straight edge. The root is long, 

 single, and flattened laterally. 



The maxillary lateral incisors are much smaller than the centrals, which they 



Fig. 9.3. — The Teeth of an Adult. 



canine bicuspids molars 



WISDOM TOOTH 



UPPER OR 



MAXILLARY 



TEETH 



(*> ll- in, LOWER OR 



MANDIBU- 



\ f \ /[ LAR TEETH 



5 



resemble in the general contour of the crown. The distal angle of the crown is 

 more rounded than in the central incisors, and the cingulum is more pronounced. 

 The root is single. The maxillary incisors are lodged in the premaxilla. 



The mandibular central incisors are much narrower than those of the upper set, 

 and less than half their width in the cutting edges, and the crown becomes contracted 

 towards the neck. The cingulum is scarcely marked, and the root single. The 

 lower lateral incisors are distinctly larger than the lower centrals in every direction. 



Fig. 94.— a Molar Tooth in section, and a Canine Tooth. 



CROWN ---^ 



CUSP fr^^yy f^' """^ 



NECK ^^-^.' -PULP CAVITY 



KlJl 



NECK 



CINGULUM 



The distal angle of the crown is rounded off; the root is single and frequently 

 presents on each side a longitudinal groove. 



The canines. — These differ from the incisors in possessing larger crowns, and 

 thick long roots. The crown ends in a blunt point, and the cutting edge slopes 

 away on each side. The slope towards the bicuspid is the longer, and causes the 

 crown to be asymmetrical. The lingual surface presents a median and two lateral 

 ridges; they converge towards the well-marked cingulum, which is often produced 

 into a distinct cusp. 



