We propose a new method for fabricating the hydroxyapatite (HAp) film in the atmosphere by the laser ablation method using Er:YAG laser. The HAp films were deposited on the Ti substrate by ablation reaction by the Er:YAG laser irradiated to target of several kinds of calcium phosphate compounds. Subsequently, the deposited film was changed to a material with HAp like structure by hydrolysis reaction with the pure water in film surface. It became clear that α-tricalcium phosphate (α-TCP) had the early sedimentation rate and that it changes to the HAp structure within 48 hours. Further, it was proven that the film became the HAp structure in about 3 hours, when it formed a TCP films by applying monocalcium phosphate solution with the pH 5.5 on the enamel surface. The interface of enamel and deposited layer is observed by scanning electron microscope (SEM), and it was confirmed that dense HAp film with the thickness of about 10～20μm had been formed on the enamel. It seems that the technique becomes the technology which will be very useful for the repair of the dentine in future.

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Platelet concentrates (PC) is classified into six categories, depending on their contents: leucocyte- poor or pure platelet- rich plasma(P- PRP),leucocyte- and platelet- rich plasma (L- PRP),leucocyte and platelet poor or pure plasma(L- PPP), leucocyte- poor or pure platelet- rich fibrin(P- PRF)concentrated, leucocyte- and platelet- rich fibrin (L- PRF)concentrated and leucocyte and platelet poor or pure fibrin(L- PPF）concentrated. We obtained two types of PRPs, red- PRP and yellow- PRP, named according to their color, from whole blood without anti- coagulant chemical agent, using centrifugation (400g x 10 min.) in plastic tube made of polypropylene, delaying clotting time. The red- PRP included the collecting from the plasma layer with buffy coat. On the other hand, the yellow- PRP included the collecting from the plasma layer without buffy coat. The mean counts of platelets between the red- PRP and the yellow- PRP were not significantly different, although they were about 1.43- and 1.28- fold higher than in whole blood, respectively. Although the red- PRP contained 70% of leucocytes compared with whole blood, the yellow- PRP kept merely 10% of leucocytes compared with whole blood and completely lost neutrophil fraction. These results indicate that the red- PRP and yellow- PRP are equivalent to L- PRP and P- PRP, respectively. We also obtained two types of PRP gel, red- PRP gel and yellow- PRP gel were fabricated using centrifugation of red- and yellow- PRP at 650g for 10min. in glass tubes. Histological examination of the red- PRP gel showed that it consisted of three layers from the bottom to the top, the mixture of leucocytes and erythrocytes, platelets and compressed fibrin. Histological examination of the yellow- PRP gel showed that it consisted of two layers, platelets at bottom and compressed fibrin at top. In the yellow- PRP gel, we didn’t find the mixture of leucocytes and erythrocytes. These results indicate that the red- PRP gel and yellow- PRP gel are equivalent to L- PRF and P- PRF, respectively. The manipulations of these plastic tube and glass tube method could lead to the easy generation of the various sort of PC for the effective and safety clinical applications as a point- of- care method.

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Carbonate containing hydroxyapatite (CHAp) thin films and magnesium containing hydroxyapatite (Mg-HA) thin films were prepared using rf-magnetron sputtering method. The CHAp films were coated onto a titanium (Ti) and a silicone (Si) substrate from a hydroxyapatite (HA) powder target, which were undertaken in a mixed CO2 /Ar gas. The ratio of the CO2 gas to the Ar gas was varied in the ratio of 0:10, 2:8, 4:6, 6:4 and 8:2. The Mg-HA films were coated onto a Ti substrate and a filter paper from a mixed HA/MgO powder target, which were undertaken in an Ar gas. The molar ratio of Mg to Ca in the mixture target was varied in the ratio of 0:10, 2:8, 4:6, 6:4 and 8:2. The chemical compositions of the CHAp films and the Mg-HA films sputtered Ti substrates were determined by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). In addition, the CHAp films sputtered Si substrates were analyzed by fourier transform infrared spectroscopy (FT-IR). The Mg-HA films sputtered filter papers were heated at 700℃ to remove the filter paper and obtained Mg-HA powders. The crystal lattice parameters from XRD patterns of Mg-HA powders were calculated. The chemical analysis by XPS showed that only a surface of the CHAp films contained carbonate, and Mg-HA films contained Mg. The XRD patterns of the Mg-HA films showed that the peak positions of HA was shifted to higher angles because of Mg substitution for Ca in the HA structure. The XRD patterns showed that the Mg-HA powders were composed of HA, beta-tricalcium phosphate (β-TCP) and MgO. The lattice parameter of the identified β-TCP in the Mg-HA powders (Mg:Ca=2:8, 4:6 and 6:4) were smaller than that in the HA powder (Mg:Ca=0:10).

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It is pointed out as a weakness of one-piece implant that it is difficult to use the implant at the insufficient bone mass site because of lack of initial fixation after implantation and loosening by occlusal force. In such cases two-piece implants have been preferentially used. However, two-piece implants also have a few weaknesses that they are complicated operation, lower mechanical strength, long healing period, and so on. On the other hand, HA coated implants can be early fixed with bone after implantation due to the osteoconductivity of HA. Therefore, it was considered that one-piece HA coated implants can be used at the insufficient bone mass site. From this point of view we have reported a few papers that the one-piece HA coated implants (AQB implants) were successfully used clinically at the insufficient bone mass site. Furthermore, in this paper a new alveolar bone regeneration therapy was developed by combining one-piece HA coated implants and autologous bone graft.

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