Epithelial remnants in the crestal periodontium of the dog

The purpose of this study was to access the effect of age on the epithelial remnants (EPRs) of the crestal periodontal tissues of beagle dogs. The material consisted of 10 beagle dogs; 5 were 1‐year‐old (young dogs) and 5 were 9‐years‐old (old dogs). All animals belonged to the same dog colony and had been raised under similar conditions. Since birth, the dogs had been subjected to professional prophylaxis 4 ×/per year. Biopsies were obtained from the man‐dibular 3rd and 4th premolar regions and were prepared for histologic analysis. 2 areas, (1) the supracrestal region and (2) the marginal periodontal ligament region, were identified. The supracrestal region was further divided into 4 compartments of equal height. The histologic parameters studied included: the (i) number of EPRs/mm root length; EPR frequency; (ii) size of EPR; (iii) distance between the root surface and the EPR; (iv) distance between the alveolar bone and the EPR; (v) epithelial cell area. The supracrestal region (total and various compartments) of old dogs harbored significantly fewer yet larger EPRs than epithelial remnants of young dogs. Similarly, the EPR's of the periodontal ligament region were significantly larger and closer to the root surface in old dogs compared to young dogs. No difference was noted in the cell area of EPRs between young and old dogs for cither region. Epithelial remnants of the supracrestal region in both groups of dogs were somewhat more frequent, larger and positioned further from the root surface than the EPRs of the periodontal ligament region. Within the 4 compartments of the supracrestal region, the EPR frequency was less and the EPR size larger in old than in young dogs, with the most dramatic difference occurring in the most coronal compartment. It was concluded that EPRs are a normal constituent of the periodontal tissues of the permanent dentition of the beagle dog which undergo distinctive changes with age.