302 MICROSCOPIC ANATOMY OF THE TEETH 



able to expect that the same process of absorption accom- 

 plished by the same agents would be found in the teeth. 

 Osteoclasts have been shown to be present in the absorption 

 of the dentine of implanted teeth, by Wilkinson, and were 

 also present within the lacunae of Howship in the absorption 

 of the implanted tooth in a dog, in Scheff s implantation 

 experiment. 



In the roots of teeth which have been the subjects of 

 slight pathological changes, alternations of absorption and 



FIG. 197. Absorption of dentine in permanent molar. Howship's 

 lacunae and osteoblasts. Weil process. (x!50. ) 



deposition are seen to have taken place, the semilunar 

 excavations in both bone and dentine being occupied by 

 a deposit of cement, sometimes containing ordinary branched 

 lacunae and canaliculi and sometimes small lacunae destitute 

 of processes. In an abscessed tooth large portions of the 

 root are often seen to be excavated and absorbed by 

 the osteoclasts (fig. 198). 



As previously stated, both in the bone and in the per- 

 manent teeth alternations of absorption and deposition are 

 seen, in the permanent teeth generally as the result of 

 pathological conditions, but in the formation of the roots 

 of permanent teeth this alternation can often be detected. 



