658 THE TEETH. 



Hyperplasia. An intense plastic pericementitis, or repeated attacks of a 

 so-called subacute inflammatory process, will lead to a new formation of con- 

 nective tissue, cementum, and bone. 



Hyperplasia of pericementum occurs whenever a large number of inflam- 

 matory corpuscles are newly formed and remain in connection with each other, 

 thus not ceasing to be a tissue. The inflammatory corpuscles in certain dis- 

 tricts become elongated, and, after having split into spindle-shaped elements, 

 are transformed into a solid basis-substance, which means a new formation 

 of connective-tissue bundles. These bundles differ from those of normal 

 pericementum in their greater density, and their very irregular arrangement. 

 Hypertropied cementum is augmented in its whole bulk, and is built up by 

 coarse bundles of connective tissue, between which, in the earlier stages of 

 the hyperplastic process, more or less numerous nests of inflammatory ele- 

 ments are seen. In other instances, the whole pericementum is transformed 

 into a dense cicatricial connective tissue, whose bundles are very small, and, 

 by crossing each other in all directions, produce a felt-work. Hyperplastic 

 pericementum, as a rule, holds fewer blood-vessels than the normal. 



Sometimes scattered nests of the inflammatory corpuscles take up a high 

 refracting power, which evidently is due to a deposition of lime-salts in them 

 the so-called calcification. This process is entirely different from ossifica- 

 tion, though the former apparently precedes the latter. Scattered nests of 

 inflammatory elements may be transformed also into clusters of fat-granules. 



New formation of cementum is observable in two forms : either as re- 

 formation in the bay-like excavations, or as a new formation on the outer 

 surface of the cementum. 



Re-formation of the cementum is always characterized by a deposition 

 of lime-salts in the territories of the cement-corpuscles, previously dissolved 

 by the inflammatory process. The bay-like excavations remain unchanged 

 in their configuration, even after new cementum has formed. In the cemen- 

 tum of both the neck and the root I have met with such sharply circum- 

 scribed islands of newly formed cementum, apparently in no connection with 

 the outer surface. 



The inflammatory new formation on the surface of the cementum appears 

 either in the shape of a continuous layer of cement-tissue, distinctly bounded 

 toward the normal cementum, or jagged on the outer surf ace, with manifold 

 elongations and erosions, filled with newly formed connective tissue. Some- 

 times relatively large globular formations appear on the outer surface of the 

 cementum as the result of perieementitis. 



There are globular bodies in connection with the cementum by means of a 

 pedicle, which closely resemble those in the pulp-cavity attached to the den- 

 tine. These peculiar formations exhibit a distinct concentric lamination. 

 They are surrounded by a layer of spindle-shaped medullary elements, and 

 hold in their centers a radiating bioplasson mass, resembling a bone-corpus- 

 cle. As to their origin, there can be scarcely any doubt that they arise from 

 clusters of medullary or multinuclear bodies, above described. All new for- 

 mations on the surface of the cementum, caused by an inflammatory process, 

 may be justly denominated "exostoses of the cementum." (See Fig. 289.) 



I have repeatedly seen true bony new formations in hyperplastic perice- 

 mentum. They appear in the shape of irregular islands or elongated spiculse 

 within the fibrous connective tissue, sometimes so near to the cementum that 

 no doubt is left about their formation in the middle of the pericementum, 



