DENTAL HARD TISSUE DESTRUCTION 127 



surface ("internal canals"); in other words, many specimens were 

 attacked from both inside and outside. This type of destruction con- 

 sistently exceeded in frequency the other types in all the material 

 studied, except the few teeth obtained from the Guatemala Indians, 

 which showed predominantly a more diffuse disintegration. 



Typical surface erosions were less frequent. In the Greek material, 

 approximately 40 per cent of those teeth which were affected by 

 postmortem changes showed histologically recognizalDle erosions on 

 the cementum surface of the roots, and 30 per cent on the enamel 

 surface of the crown. The degree of postmortem disintegration gives 

 no reliable clue as to the age of the various groups of material. Of 

 the 23 teeth from the Norwegian Middle Ages, less than 500 years 

 old, nearly all (90 per cent) showed postmortem changes, exceeding 

 the frequency found in the teeth from prehistoric Greece, which had 

 been buried for several thousand years. 



There was a suggestion, however, that the teeth obtained from 

 the various periods of Greek history have become increasingly af- 

 fected with the increase in postmortem age. Thus, 80 per cent of 

 the prehistoric teeth were affected as compared with 25 per cent of 

 those from the New Greek period. The erosions showed the most 

 consistent increase in frequency with increasing postmortem age of 

 the material. In fact, the only Greek teeth which exhibited this type 

 of disintegration in a relatively large number of cases were those 

 dating from the prehistoric period. The fact that no postmortem 

 changes were observed in the teeth from the predynastic Egyptian 

 and the Old Icelandic period may only serve to show that the post- 

 mortem age of single teeth in certain burial grounds cannot be pre- 

 dicted bv the absence, presence, type, or degree of postmortem 

 disintegration. 



Origin of the Postmortem Lesions 



Among the various dental diseases described by Hopewell-Smith 

 (1918) in his textbook on histopathology of the teeth, he refers to 

 two cases of a disease which he calls "fungoid excavations." The 

 sections which Hopewell-Smith used for illustrations show what ap- 

 pear to be types of canals in the dentin similar to those which in 

 the present study have been attributed to postmortem changes. He 



