The roles of the gubernaculum dentis, root formation, tooth crown and dental follicle in pre‐functional eruption of a mandibular premolar have been studied in nine beagle dogs by radiographic and histologic evaluations of the effects of surgical ablation or removal of these structures on tooth eruption. The dental follicle was the only one of these structures required for the coordinated enlargement of the eruption pathway and formation of bone in the base of the bony crypt, the radiographic and histologic hallmarks of tooth eruption. These data, together with the topographic relationships of the dental follicle to areas of localized bone resorption and formation, are interpreted to mean that the dental follicle may influence, if not coordinate, these processes in tooth eruption.

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Previous studies from our laboratories have shown that premolar eruption in dogs depends upon the presence of the dental follicle and is independent of root or crown growth or attachment to the oral epithelium. The present study is an analysis of the cellular composition of the dental follicle and the cellular investment of the adjacent walls of the bony crypt before and during eruption of the third and fourth mandibular permanent premolars in young beagle dogs. Four premolar follicles and their adjacent bony crypts were examined at 2-week intervals over 12 weeks before and during eruption of these teeth. Tissues were removed, fixed, processed, and oriented so that each follicle and the adjacent crypt wall could be reproducibly examined in vertical and horizontal planes. Mononuclear cells with abundant cytoplasm, euchromatic nuclei, and prominent nucleoli were present in juxtavascular location in the coronal part of the dental follicle; and these cells increased in number immediately preceding and during tooth eruption in parallel with an increase in osteoclasts on the adjacent crypt wall. These data are interpreted to mean that the coronal part of the dental follicle may coordinate the alveolar bone resorption required for tooth eruption by attracting and directing to the crypt wall a population of mononuclear cells, which either become osteoclasts and/or direct osteoclastic activity during tooth eruption.