Figure 3. Electron micrographs of internal (a) and superficial (b) hard tissue in the 14-day transplant. (a) Numerous vesicle-like structures (arrows in the insert) are present in the extracellular matrix. An intact cell (asterisk) containing well-developed cellular organelles is also seen. (b) Matrix vesicles (arrows in the insert) are observed in the extracellular matrix. Go, Golgi apparatus; N, nucleus; rER, rough-surfaced endoplasmic reticulum. Scale bar: 2 µm (a,b), 0.2 µm (inserts of a,b).