Bundle bone

Bundle bone is that bone in which the principal fibers of the periodontal ligament are anchored. The term bundle was chosen, because, the bundles of the principal fibers continue into the bone as Sharpey’s fibers. The bundle bone is characterized by the scarcity of the fibrils in the intercellular substance. These fibrils, more over, are all arranged at right angles to Sharpey’s fibers. The bundle bone contains fewer fibrils than does Lamellated bone, and therefore it appears dark in routine hematoxylin and eosin stained sections and much lighter in preparations stained with silver than does lamellated bone. These fibers are mineralized at the periphery and have a larger diameter. These fibers are less numerous than the corresponding fiber bundles in the cementum on the opposite side of the periodontal ligament. The collagen adjacent to bone is always less mature than that adjacent to cementum. In some areas, the alveolar bone proper consists mainly of bundle bone. Bundle bone is formed in areas of recent bone apposition. Lines of rest are seen in bundle bone.

Radiographically, it is also referred to as the Lamina dura, because, of increased radiopacity, which is due to the presence of thick bone without trabeculations, that X-rays must penetrate and not to any increased mineral content.

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