OPERATIONS ON THE TEETH. 333 



though at a given time it may remain stationary, hard and resist- 

 ing. Again, as the progress of the disease continues, the hj^^er- 

 trophied dental root, by its continued pressure outward, may 

 destroy the external surface of the bone, and form a communica- 

 tion between the bottom of the diseased alveola and the external 

 plate of the maxillary. In these cases pus, saliva and putrefied 

 food coUect or filtrate into the subcutaneous cellular tissue, and an 

 abscess is formed which soon ulcerates and empties itself on the 

 surface of the cheek. Once open, this abscess has no tendency 

 to heal, but, on the contrary, mamtaius its fistulous form, and dis- 

 charges through its opening a mixture of pus, saliva and food, 

 havmg the very repulsive and characteristic odor already men- 

 tioned. Exploration of this fistula with the probe wiU give different 

 results according as the fistulous tract is straight or irregular. 

 In the first instance, the probe wiU penetrate directly into the 

 mouth, opening on one of the faces of the diseased tooth, or even 

 passing iuto the center of its carious crown ; while in the other 

 case it is arrested by the spongy substance of the ulcerated max- 

 illary; or it may strike against the root of the diseased molar. 



At this point, changes will have taken place in the mouth, 

 upon the surface of the teeth, on the side of the jaw where the 

 disease exists. These changes vary, and consist either in a great 

 obhquity of the tables of the teeth, the crowns or rubbing sur- 

 faces being beveled in very obUque and opposite directions, or in 

 the weU. marked elevation or projection of the molars correspond- 

 ing to the diseased grinders, in the healthy jaw; a projection 

 which is in proportion to the diminished size of the opposite 

 carious tooth which stands much lower. The first condition is 

 observed when the paia caused by the caries has entirely prevent- 

 ed mastication on the diseased side, and the second, when, not- 

 withstanding the caries, the performance of mastication has still 

 continued. 



The condition then presented by the carious tooth may also 

 vary. In some cases it may stUl be complete in its alveolar con- 

 nection, though otherwise partly destroyed, and yet firmly ad- 

 herent by its root. In others it may be broken, entirely or in 

 fragments, merely parts of the outer surface being present; 

 while again, some broken fragments, more or less detached, may 

 remain in the alveolar cavities. 



Caries of the first and second superior molars may become 



