Scanning Electron Microscopy of Ti Disc Circumferential Surface.
The modified sandblasted surface group was distinctive from the smooth surface group with respect to the topographic properties of the circumferential surface. The topography of the smooth surface group was smooth, having only some small parallel scratches (Fig. 2). The modified sandblasted surface, however, was rather rough, but the profile was fairly round. There were numerous secondary micropores inhabiting the rough macrotexture; the average diameter of which was about 2.0 mm. No AL2O3 particles were found embedded in it (Fig. 3).

Follow-up Observation with Phase- Contrast Microscope.
After 3 days of culture, discs of the smooth surface group were completely surrounded by a refractile band that appeared uniform in brightness with the cell contours of a parallel orientation and a sharp and regular border. The refractile band in the modified sandblasted surface group was not uniform and had an irregular border. Also, the migrating cells were perpendicular to the Ti disc circumference (Fig. 4). At a high magnification (3400), the refractile band was shown to be a multi-layer structure of cells that oriented themselves in a certain way. In the smooth surface group, cells within this refractile area were mostly attached and parallel to the Ti disc circumference. The attaching cells were long and spindle-shaped. In the modified sandblasted surface group, however, cells attached to the rough Ti disc circumference in a perpendicular manner and the interfacial cells were triangular or multangular (Fig. 5).
After 7 days of culture, the attaching and orienting cells increased and the refractile band became broader and brighter. The respective performance of each group was similar to that of the third day, and the differences between the two groups were retained and even expanded.

Histologic Observation.
In the horizontal-plane sections, a cell-band arc consisted of tens of cellular layers with the inner side being the Ti-osteoblasts interface with intact histologic structure. The nuclei of cells were oval shaped and stained purplish red, and the cytoplasm was stained pink.
The smooth surface group. There were a few cells in this section. Most of them were located opposite the interface. The cell shapes were short spindle or triangle. Long spindle shaped cells with little cytoplasm lined the interface (Fig. 6a).
The modified sandblasted surface group. Compared with the smooth surface group, the cell number was larger. Cells of various shapes, mainly round or oval, lined the rough interface. Cytoplasm was abundant, and the nucleus deviated away from the interfacial side. The cells at the interface attached to the rough surface at angles and many collagen-like fibers attached to it in the same way (Fig. 6b).

Ultra-Structure Observation.
Apart from the differences in morphology and orientation of interfacial cells demonstrated by ordinary microscopy, the modified sandblasted surface group was also distinguished from the smooth surface group by the morphological phenotypes of cellular function. Compared with the smooth surface group, the modified sandblasted surface was mostly lined by rectangular cells, more abundant in cytoplasm and endoplasmic reticula, and more active in secretion of collagen fibrils (Fig. 7). Furthermore, it was distinguished from the smooth surface by the process of bone matrix mineralization mediated by bone matrix vesicles (Fig. 8) and the formation of osteocytes trapped by mineralized collagen fibrils (Fig. 9). These bone matrix mineralization phenomena were hardly discernible in the smooth surface group.