\"ii. \rr\Mi\ \ I)i;fi(Ii;.\(> i\ animals 



1.") 



I-'k;. 29. \'itainiii A (Icficioncv in i m i ,ii . I ppci- incisor tooth in onrly rppnir follow- 

 ing restoi-ation of vitamin A in I lie diet. Note the ixTsistencc of cohiinnai- odonto- 

 l)lasts and thickness of dcntino in rehition to the o(h)ntogenic ei)it helium on the 

 lahial side. Elsewhere the dentine is thin or even absent, with plication and inclusions 

 of odontogenic epithelium. The odontoblasts, in spite of some "■picdcnt ine" foi-ma- 

 tion. have not \et resumeil normal a])pparance. 



'/ a/.-' Repair seciiieiice.s are simple and dramatic. Restoration of function 

 and morphology of the odontogenic epitheliimi is followed by the resimip- 

 tion of nioi'phology and dentine deposition l)y odontoblasts. The repair 



21 I. 8chour. M. M. Hollman, and M. C. Smith, A»i. ./. I'alhol. 17. 529 (1941). 



