DENTAL HARD TISSUE DESTRUCTION 121 



The teeth from the Norwegian Middle Ages were obtained from 

 the anthropological collections at the University of Oslo, through 

 the late Dr. E. K. Schreiner, former Museum Director. 



The Pecos Indian teeth, which represented the largest number 

 from one single source, as well as the predynastic Egyptian and 

 Guatemalan specimens, were all obtained from Harvard's Peabody 

 Museum, through the cooperation of the late Professor Earnest A. 

 Hooton, who gave much impetus to this investigation. Through his 

 interest and that of Professor Hallan L. Movius, also of Harvard's 

 Peabody Museum, it became possible to examine histologically sev- 

 eral valuable specimens from the Stone Age people of Mount Carmel 

 in Palestine, originating from the upper Pleistocene period. 



Gross Exa7Jiination 



Examined grossly, before the teeth were prepared for histologic 

 examination, the enamel covering the crowns of the teeth was gen- 

 erally surprisingly well preserved. Even some of the oldest specimens 

 had retained a normal hard and glossy enamel surface. Occasionally, 

 localized areas of the enamel surface exhibited a dull porous appear- 

 ance as if etched by acid. Minor enamel fractures were of common 

 occurrence. Thus, more than one-third of the teeth from various 

 periods of Greek history presented grossly visible cracks and frac- 

 tures, which were probably due to drying and handling. 



The root surface of many of the exhumed teeth presented a dry, 

 porous, and dull appearance. Upon further examination such speci- 

 mens could be divided into two categories. In one, the x-ray ab- 

 sorption and weight of the teeth were equal to or exceeded the 

 average for normal teeth. When submerged in 10 per cent nitric 

 acid, the roots of such teeth seemed to be abnormally acid resistant. 

 Removal of the mineral component left a meshwork unlike the 

 leathery matrix of freshly extracted teeth similarly decalcified. This 

 difference may have been due to a partial replacement of destroyed 

 areas of dentin by highly mineralized matter. 



The other category presented a similar surface appearance (Fig. 

 19), but the x-rays readily penetrated a large portion of the teeth 

 (Fig. 20). The radiolucent area was most evident at the tip of the 



