Study of Three Dimensional Ultrastructure of the Formative Bone Surface

Abstract

To observe three dimensional ultrastructure of formative bone surface, the surface of mandibular bodies and bony palates of 4-week-old Wistar rats were examined by high-resolution scanning electron microscope. Specimens were incubated in trypsin solution to digest both the osteoblasts and amorphous organic matrix, and the formative bone surface was exposed. Most of the surface matrix of the formative bone was composed of a dense network of collagen fibrils. Compact collagen fibrils were observed running in a uniform direction under the reticular collagen fibrils with sparse reticular collagen fibrils at the bone surface. On some parts of the formative bone surface, irregularshaped or semi-spherical ultrastructures were observed. These ultrastructures were formed by dense networks of collagen fibrils. Compact collagen fibril bundles running roughly in a uniform direction were found partially on the formative bone surface. Spindle-shaped bone canaliculi opened between collagen fibril bundles. Uncalcified collagen fibrils forming the formative bone surface were approximately 70 nm (700 Å) in diameter and had periodic striped structures at about 60 nm (600 Å) intervals.