Key Engineering Materials Vols. 309-311

Abstract: Salivary calculus is an ectopic calcification of high frequency in oral region. Many previous reports on the composition and structure of salivary calculus only showed apatite crystal as the main constitution but were not sufficient to clarify the formation mechanism. In this study, structural properties of the salivary calculus were investigated by the high-reproducibility non-destructive method such as optical microscope, micro-CT, micro-FT-IR and micro-XRD. In some cases, SEM, BSI, and EDS analysis were also carried out. The results showed that the salivary calculi were grouped into three by structure, and grouped into three or four by chemical composition and crystal components. The difference in structure and composition should be reflected by the formation mechanism.

Abstract: We investigated the immediate response in the vicinity of the implanted polarized hydroxyapatite (HA). One of the important immediate events was found to be the fibrin adsorption on the implanted HA. The activation of the fibrin adsorption on the polarized HA was confirmed by the observation by SEM observation and immunohistochemical detection. After the implantation, the coagulation cascade induced the wound healing. The adsorbed fibrin was formed network structure and worked for later cell responses as the scaffolds. The acceleration of fibrin scaffolds formation in the vicinity of the implanted polarized HA contributed to the stimulation and activation of plate ets and osseous cells. The platelets were activated from the results of the signal transduction and cytoskeleton changes and released growth factors. The growth factors released from platelets led to bone regeneration by stimulating migration and proliferation of the osseous cells. In the vicinity of the implanted HA samples, the coagulation cascade reaction to repair wound healing led to the new bone formation by mediation of the platelets and osseous cells. The mechanism of osteoconduction at earlier stage had close relationships to the electrostatic properties of the implant.