Root resorption leading to linkage of dentinal collagen and gingival fibers?

A maxillary central incisor in a 55-year-old Caucasian female was extracted in modified block as part of a histologic study of gingival responses to subgingival crown placement. The facial portion of this block showed preclinical pocket depth of 1.0 mm with moderate gingival inflammation. The block was extracted 2 weeks after crown placement and prepared for histologic evaluation. Histologic responses to subgingival crown placement were, among others: gingival recession (1.0 mm), reformation of crevicular depth (0.7 mm) and remodelling of the gingival and periodontal attachment apparatus. Histologic evaluations of the gingival unit using cellular and connective tissue stains revealed an area of root resorption immediately apical to the junctional epithelium at a portion of the facial surface. Root resorption had progressed into dentin. Gingival connective tissue abutted the dentinal surface. Collagen stains showed the presence of tufts of collagen fibrils which appeared to arise from the dentin. These fibrillar elements seemed to splice with collagen fibrils found in the gingival connective tissue. The specimen thus suggests the possibility of a fiber linkage attachment involving exposed dentinal fibers as part of gingival repair following injury.