Abstract
Ultrastructural and morphometric analyses were performed on periodontal fibers adjacent to the mid-root cementum of human permanent teeth. The results were as follows. 1. Periodontal fibers of intact teeth and periodontium exhibited bundles of densely packed collagen fibrils attached to the cementum surface with a regular arrangement. Collagen fibrils revealed a parallel and regular arrangement with periodic cross banding. The cross-sectioned collagen fibrils had a circular and uniform distribution. 2. Periodontal fibers on marginal periodontitis revealed an irregular arrangement with few bundles of packed collagen fibrils. Only a few periodontal fibers were attached to the cementum surface. Collagen fibrils had an irregular arrangement with destruction and decrease. Collagen cross banding was faintly visible in some remaining fibrils. Variously sized cross-sectioned collagen fibrils revealed an unclear outline without uniform diameter and distribution. 3. The cross-section area of intact collagen fibrils was 1.99×103nm2 and that of the periodontitis was 1.47×103nm2. The difference was significant at 0.1% level.
