276 MICROSCOPIC ANATOMY OF THE TEETH 



Von Ebner says : ' Without doubt the odontoblasts are the 

 essential and sole dentine formers in the growth of typical 

 normal dentine ; they are the gelatine-yielding cells as well 

 as the lime-salt producers ; under special conditions other 

 cells of the pulp can, however, lay down a dentine-like 

 substance.' l 



That calcification can take place in the pulp independently 

 of the odontoblasts is seen in the formation of pulp-stones 

 and irregular calcific deposit, and is consistent with what is 

 shown of calcification in degenerations of connective tissues 

 elsewhere. 



A comparison of fig. 177, where the connective-tissue fibres 

 of the periodontal membrane are entering the forming 

 cement, with figs. 169 and 171 showing the incorporation 

 of connective-tissue bundles in the pulp with the dentine, 

 is interesting as showing the great similarity of the appear- 

 ances in the two tissues. 



To recapitulate : 



Summary. (1) In the early development of the dentine, connective- 

 tissue fibres from the pulp pass in bundles into the forming 

 dentine in a more or less radiating manner, but they do not 

 course, within the dentine, in a direction parallel to that of 

 the tubes, but transversely to them. This incorporation 

 of the connective-tissue fibres is not immediately connected 

 with the calcification of the matrix. The fibres at this stage 

 are not lime-containing and do not show double refraction, 

 but they form an organic foundation or scaffolding in which 

 calcification takes place. 



(2) It is not only in the earliest stages of dentine formation 

 that this meshwork of foundation tissue is laid down, but 

 it also occurs throughout the active growth of the dentine, 

 although in the later stage the fibre bundles have not the 

 regular arrangement described by Von Korff in the early 

 stages of development. Bundles of connective tissue are, 

 however, evident, which are becoming incorporated with the 

 forming dentine in later stages and appear to be analogous 

 to the penetrating fibres of Sharpey in bone. 



(3) In teeth in use, in which the first formation of root and 

 crown is completed, but the cells at the circumference of the 



1 In a letter. 



