The purpose of this study was to perform a three-dimensional observation, via microvascular corrosion casts, of the microcirculation system during deposition of cementum after flap surgery and to investigate the permeable structure of the vascular endothelium. Two stages of wound healing after flap surgery were confirmed based on successive vascular changes. The transition between these stages occurred 3 weeks after surgery, at which time new blood vessels disappeared and an early stage of accumulation of new cementum was apparent. Hence, fibrous repair occurred during the first stage, and repair of hard tissue (ie, formation of cementum) occurred during the second stage. These findings suggest that metabolic activity in cementogenesis is low, based on the condition of the blood vessels, and therefore new cementum is not easily formed.