86 VE TERINAR Y DENTAL SUXGEXY. 



Fig. 22 is a drawing 

 made from a tooth which 

 represents a very common 

 form of caries. A fissure 

 (a) in the crown extending 

 from the interior to the pos- 

 terior edge of the tooth, 

 dividing it into nearly equal 

 parts, extends down the side 

 (6) to the root. This is a 



FIG. 22. 



very c o m m o n f o r in of 



A LONGITUDINAL FISSURE 



THE RESULT OF CARIES, caries, and usually termi- 

 nates in longitudinal fracture of the tooth from the 

 crown to the root. The fracture is the result of 

 food collecting in the wedge-like groove and forcing 

 it apart. Feed will accumulate in the fissure often 

 giving a round bulging appearance to the cheek, 

 which subsides as soon as the accumulation is arti- 

 ficially removed. Should the round, bulging appear- 

 ance be due to paralysis of the muscles of the cheek, 

 it will remain more or less pendulous after the feed 

 has been taken away. 



The fourth molars are more liable to caries than 

 any of the other teeth. This is due no doubt to the 

 fact that they are the first permanent teeth to make 

 their appearance, consequently they are less devel- 

 oped than those which appear later in life. Being 

 the first permanent teeth erupted they are subjected 



