DENTO-ALYEOLAR RESORPTION IN PERIODONTAL DISORDERS 315 



The clinical obseivatioiis and histological findings mentioned 

 above indicate that tooth resorptions are caused by circulatory dis- 

 turbances. An explanation has been suggested as to the reason why 

 tooth resorptions occur more seldom than resorptions of the al\ eolar 

 bone. 



Summary 



Alveolar bone resorption in periodontal disorders has been dis- 

 cussed in relation to local circulatory disturbances, increased func- 

 tional stress, and general systemic influences. 



1. Histological observations indicate that circulatory disturbances, 

 which increase the tissue tonus in the periodontium, initiate alveolar 

 bone resorption, and that a reduced flow of blood in the periodon- 

 tium may impede the production of alveolar bone. 



2. When the masticatory functional stress is raised to a certain 

 limit it stimulates a compensatory production of alveolar bone, 

 whereas if it is increased above this limit pathological changes 

 appear, including destruction of alveolar bone. 



3. Systemic conditions may influence the loss of alv^eolar bone 

 by' inciting and aggravating periodontal circulatory disturbances, 

 and by preventing new formation of alveolar bone. 



4. On the pericemental side of the lamina dura there usually 

 are some areas not covered by pericemental fibers, particularly near 

 the canals where branches of the interalveolar vessels enter the 

 pericementum. This may be the reason why alveolar bone is resorbed 

 before the teeth, which, according to histological observations, do 

 not undergo root surface resorption where pericemental fibers are 

 intact. 



References 



Albright, F., and Reifenstein, E. C, Jr. 1948. The Parathyroid Glands and 

 Metabolic Bone Disease. Williams and Wilkins Co., Baltimore, Md. 



Andresen, ^^, Hiiupl, K.. and Petrik, L. 1957. Funktions-Kieferorthopadie. 

 Johann Ambrosias Barth, Munich. 



Baer, P. N., and Lieberman, J. E. 1960. Periodontal disease in six strains of 

 inbred mice. /. Dental Research, 39, 215-255. 



