Electron microscopic study of the junction between surgically denuded root surfaces and regenerated periodontal tissues

The ultrastructural features of the junction between regenerated periodontal tissues and surgically exposed root surfaces were investigated in monkeys. Specimens were studies at intervals of 1 to 18 months. Specimens at all time intervals demonstrated regeneration of the junctional epithelium to both dentin, as well as cementum surfaces. Epithelial reattachment was present on intact, as well as altered root surfaces. Cemental regeneration was also noted in all specimens, but ap‐ peared generally confined to the most apical portion of the wound. Cementum formed over dentin, as well as cementum. A dense, granular layer, possibly of a polysaccharide‐protein nature, was frequently noted at the interface of new cementum and the surgically exposed dentin or cementum. Artifactitious splits, apparently occurring during the demineralization phase of tissue processing, frequently involved this granular layer. It is suggested that these splits result from processing and do not reflect a lack of cohesion or adhesion within the regenerated periodontium. This investigation was supported by the United States Public Health Service, Center for Oral Health Research, University of Pennsylvania, Grant No. DE‐02623. The technical assistance of Miss Rollande Tremblay and J.P. Smith is gratefully acknowledged.