Dental Hard Tissue Destruction 

 with Special Reference 

 to Idiopathic Erosions 



REIDAR F. SOGNNAES, School of Dentistry and School of Medicine. 

 Center for the Health Sciences, Iniversity of California. Los Angeles. 

 California 



MECHANISMS of hard tissue destruction within the jaws and 

 teeth involve the full spectrum of vertebrate hard tissues: enamel, 

 dentin, ivory, cementum, and bone. Biological elements that are pre- 

 sumed to be directly or indirectlv responsible for the destructive 

 processes range from the minute bacteria of dental decay to the 

 large osteoclasts of tooth and bone resorption. In addition there are 

 involved various physical and chemical agents from endogenous as 

 well as exogenous origins, some known ( masticatory wear and acidic 

 juices), others hitherto poorlv understood (idiopathic and sapro- 

 phytic erosions). The latter will be the principal focus of interest 

 in this discussion. 



The situations in which the dento-alveolar hard tissues are de- 

 stroyed range from normal physiological phenomena of growth, 

 eruption, shedding, and aging to miscellaneous pathological proc- 

 esses of s\'stemic and local etiology. Furthermore, as will be ampli- 

 fied later, these xarious processes of hard tissue destruction are not 

 entirely one wav, there being evidence of redeposition of calcified 

 matter at certain stages. Finally, even if teeth and jaws (notwith- 



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