It is popular in these days to use a CT simulation data to determine the bone graft volume in dental implant cases with bone defect and the precise implant placement position. However there has been no report on converting the simulation data three-dimensionally to fabricate bone augmentation materials. In this study a HA bone graft was fabricated from a sintered HA block using a CAD/CAM technique based on the bone augmentation volume data determined by the simulation data. The HA graft was evaluated by comparing with a resin graft model fabricated by a three dimensional printing (3DP) method based on the same simulation data. The HA bone graft by CAD/CAM and the resin bone graft by 3DP was well consistent each other in the shape , size, and adaptability.

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HA 配合歯磨剤の研磨成分に関して，比較・検討を行うため，7 種類の市販のHA 配合歯磨剤の研磨成分を抽出し，X 線回折を用いて，結晶性や結晶相の同定を行った．分析の結果，研磨成分としてHA 以外の結晶相（第二リン酸カルシウム，第二リン酸カルシウム二水和物，カルサイト）が含まれており，歯磨剤の種類により，HA の含有量は，7.1 ～ 32.8wt% と含有量に差異が認められた．また，研磨成分のHA の結晶子サイズは31 ～ 66nm の範囲であった．加熱した研磨成分のXRD 分析結果から，一部の歯磨剤においては，加熱後，リン酸三カルシウム（β-TCP）が生成したことから，Ca 欠損型のHA であることが明らかとなった．また，2 種類のHA 配合歯磨剤においては，HA 成分がXRD 分析では確認されず，HA 成分が分析限界値以下と判断された．

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Magnesium substituted hydroxyapatite (Mg-HA) thin films were coated on a titanium substrate using a rfmagnetron sputtering method in Ar gas. HA/MgO mixture powder was used as the target. 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 sputtered Mg-HA films were subjected to a hydrothermal treatment. The crystallinity of the Mg-HA films were observed by X-ray diffractometer (XRD). The solubility of the Mg-HA films were measured by an ICP analysis after immersion test in deionized water and phosphate buffered saline (PBS). The XRD patterns revealed that the hydrothermally crystallized HA (Mg:Ca=0:10) film and Mg-HA (Mg:Ca=2:8, 4:6) films were mainly an HA diffraction pattern, on the other hand, the Mg-HA (Mg:Ca=8:2) film was MgO. From the immersion test, the solubility of the HA and Mg-HA films decreased after the hydrothermal treatment. The HA and Mg-HA (Mg:Ca=2:8) films were more soluble in deionized water than PBS. However, the Mg-HA (Mg:Ca=4:6, 6:4, 8:2) films were soluble in PBS than deionized water.

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In the therapy for hypersensitivity of tooth, it is well-known that potassium (K) compounds, such as potassium nitrate and potassium bromide, are often added in toothpastes because it is believed that neurotransmission is blocked by potassium ions. Recently, we have been proposing the attachment therapy of a hydroxyapatite (HAp) sheet on dentin for hyperesthesia. It is thought that addition of K ions in HAp sheet is more effective for relieve pain of tooth hypersensitivity. In this study, we prepared a K-containing HAp (K-HAp) thin film by pulsed laser deposition and evaluated the material properties, such as solubility, crystallization and atomic composition. X-ray diffraction results showed that a-axis of K-HAp was shorter than that of the conventional HAp. Energy dispersive X-ray diffraction results indicated that K ions were contained in the thin film. From the results of Fourier transform infrared spectroscopy, the hydroxy group peaks decreased in tha inclusion of K. Inductively coupled plasma-mass spectrometry results showed that the sustained release of K ions from the crystalized K-HAp was observed. Thus, the K-HAp sheet is expected to be more effective for therapy of hyperesthesia compared with the original HAp sheet.

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Carbon felt is composed of carbon fibers and, when calcined at high temperatures in the vicinity of 2000 °C or above, exhibits specific properties, including a large specific area, low electrical resistance and high microwave absorptivity. Recently, it was found that irradiation of a pair of disc-like carbon felts arranged in parallel with a ceramic ring spacer by 2.45 GHz microwaves (MW) under atmosphere air generates a thermal discharge plasma, termed a carbon felt atmospheric pressure microwave plasma (CAMP), at the gap between the felts. The temperature of the gap increases rapidly to reach thermal equilibrium at 1200 °C or higher in approximately 20 seconds, although the temperature at the circumference of felts can be as low as 200 °C 1). In the present study, the surface nitriding and oxynitridation of titanium by CAMP under atmospheric pressure nitrogen were successfully performed using carbon felts as a MW absorbing material. In addition, the formation of hydroxyapatite (HAp) by surface contact with a simulated body fluid (SBF) was assessed. The resulting surfaces of the titanium substrates were analyzed by X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy.

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Objective: To optimize the concentration of contrast media and to compare the ability of cone beam CT (CBCT) and multidetector CT (MDCT) in detecting the adhesion of the TMJ disk by CT- arthrography. Materials and Method: The square shape phantom made by nylon thread, which was simulated for adhesive change in TMJ space was used. The eight types of threads (diameter: 0.128, 0.148, 0.165, 0.205, 0.235, 0.330, 0.405, and 0.500 mm) were joined inside the phantom in parallel at 1 mm interval. The contrast media (Omnipaque 350mg I /ml) was diluted with water, and seven types of the media with diff erent concentration, 5%, 10%, 20%, 30%, 40%, 50%, and 100%, were examined. A thread phantom was kept in the rubber balloon, which fi lled with contrast media and then placed in the TMJ space of the cadaver, so that all of the threads paralleled the F-H plane as possible. The phantom in the TMJ space was investigated using cone beam CT (CBCT) and multi-detector CT (MDCT). The voxel size was approximately 0.125×0.125×0.125 mm and 0.1×0.1×0.6 mm, respectively. Four observers independently assessed, whether the defect of contrast media by thread was present or not in 12 consecutive slices in the middle of the thread. MDCT images were examined by printed on fi lm and CBCT in computer display. Results: The detected threads in the TMJ disk space in the contrast media that CBCT was superior to MDCT. Statistically signifi cant diff erences (p　0.01) were found almost all detected threads. Conclusion: MDCT and CBCT are similar detectability, when adequate concentration of contrast media is used. However, CBCT can be used for the arthrography of TMJ with less concentration of contrast media, low radiation dose, lowest price and narrow space than MDCT.

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本研究は，インプラント体の表面性状の粗さの違いによる細菌の付着状態を確認し，インプラント体の素材によるバイ オフィルム形成および細菌付着量の違いを検討した．17.0mm× 10.0mm × 1.0mm のチタン板にSBA：サンドブラストおよび酸エッチング処理，MS：マシーンドサーフェス，RA1.5：スパッタリングHA 処理およびRA3.0：スパッタリングHA処理（RA1.5 より表面が粗い試料），4 種類の表面処理を施したものを用い，各30 枚ずつ作製し実験を行った．使用菌種はStreptococcus mutans とPorphyromonas gingivalis の2 菌株を用いた．培養条件はS. mutans はBHI 寒天培地および1％ショ糖添加BHI 液体培地を，P.gingivalis はヘミン・メナジオン添加のウマ血液寒天培地および ヘミン・メナジオン添加BHI 液体培地を使用し，37℃嫌気条件下で培養を実施した．得られたデータから，各試料に付着した細菌数（CFU）の平均値を求め，インプラントの素材による細菌付着量について比較・検討を行った．S. mutans に関しては，SBA とMS の差は認められなかったが，SBA と比較してRA1.5 は2.4 倍，RA3.0 では2.9倍の細菌付着量が確認された．P. gingivalis については，有意差は認められなかった. 実験結果においての細菌付着量には，インプラント体の表面性状や表面粗さの違いにより差が出る可能性が示唆された．

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Objective : To evaluate quantitatively the metal artifacts on 3DX Accuitomo images using the titanium cylinders in relation to various exposure protocols. Materials and method : For the evaluation of artifacts, titanium cylinders were fabricated. The titanium cylinders of 2.99 and 3.49 mm were installed in anterior and posterior segments of the plastic model of the mandible. Cylinders with heights of 15.07 mm for 2.99 mm and 15.06 mm for 3.49 mm diameter were prepared from a titanium rod. The cylinders were placed 10 mm from each other, and their positions were in two central incisors for anterior and molar regions for the posterior segment. CBCT examinations were performed with 3DX Accuitomo, FPD type (Morita Corp., Kyoto, Japan). The titanium cylinders were imaged at the same position at tube voltages of 60 and 90 kV, a tube current of 4 mA, and an exposure time of 17 seconds. The voxel size was 0.125 mm. The heights of the cylinders were measured in coronal and sagittal images. Diameter measurement was performed at the center of the cylinder. The anteroposterior (AP) and mediolateral (ML) diameters of cylinders were measured in axial images. All data were evaluated with the Image J and OsiriX image analysis software. Results : In the measurement of the heights of the titanium cylinders, the mean heights deviated from 100.85% to 101.46%, and 100.59% to 101.12 % for a single cylinder for 60 and 90 kV, respectively. For double cylinders, the mean heights were from 101.39% to 101.72%, and 101.12% to 101.12% for 60 and 90 kV, respectively. The mean diameters anteroposteriorly and mediolaterally were (102.86% to 104.01%, and 102.29% to 102.67%; and 102.00% to 103.01%, and 101.67% to 101.71%) for a single cylinder for 60 and 90 kV, respectively. For double cylinders, the mean diameters anteroposteriorly and mediolaterally were (102.86% to 104.86%, and 100.28% to 104.01%; and 102.86% to 104.01%, and 102.00% to 102.67%) for 60 and 90 kV, respectively. Conclusion : CBCT is used as an alternative to conventional CT for dental diagnosis. Artifacts can degrade the quality of images, sometimes causing instability in the diagnosis. There are some factors that may cause artifacts, such as patient positioning and the presence of metallic materials. However, for determining the bone quality of the mandible, it is necessary to evaluate preoperatively metal artifacts for successful implant installation.

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The aim of this study was to evaluate the thicknesses of cancellous and cortical bones, and to identify and measure variation in the presence and extent of the anterior loop of the mandibular canal and canal itself in the anterior and posterior regions. A total of 79 patients (52 males and 27 females; age range: 19-77 years; mean age: 49 years) were scanned by computed tomography and the data were analyzed. The means and SD of the cancellous (CAB) and cortical (COB) thicknesses ranged from 5.5 ± 1.2 mm to 11.1 ± 2.2 mm and from 4.5 ± 1.0 mm to 5.3 ± 0.9 mm for males, respectively. For females, the cancellous and cortical thicknesses ranged from 4.8 ± 1.3 mm to 10.3 ± 1.5 mm and from 3.8 ± 1.0 mm to 5.3 ± 1.2 mm, respectively. The morphology of the mandible was classified into three types: type B (62%-72%), was the most common in the anterior region for males, followed by type C (56%-58%) in the posterior region. For females, type C (25%-31%) in the posterior region and type B (18%-30%) in the anterior region were the most common types. For implant placement on the mandible, careful evaluation and full knowledge of the thicknesses of the cancellous and cortical thickness are necessary; these results can help surgeons in terms of appropriate implant operation.

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The aim of this study is to histologically compare the osseointegration of 2 types of hydroxyapatite (HA)- coated implants, a JHA implant (Kyocera Medical Ltd, Japan) and a KHA implant (Zimmer Ltd, USA), with the new　bone forming in the space under the lifted membrane (SULM) in a long-term animal experiment of one stage sinus floor elevation (SFE), without bone substitutes and mechanical loading, using canine frontal sinuses. Sixteen implants, 8 JHA and 8 KHA were placed in 4 postmenopausal beagles for 3 and 6 months. Histological observations and histomorphometric measurements were carried out with light-microscopy using hematoxylin and eosin stained undecalcified specimens. Statistical significant differences were evaluated by one-way ANOVA. The new bone formation was observed on a large area of the sinus wall and the implant surface in the SULM at 3 and 6 months in both groups. Bone implant contact rate with new bone in the SULM was 88.8±10.5% at 3 months and 77.0±7.9% at 6 months in JHA group, and 85.3±7.6 and 87.3±17.9% in KHA group, respectively. There was no statistical significant difference between the groups. It was concluded that both types of HA-coated implants have similar properties to promote a superior osseointegration with the new bone forming in the SULM. Furthermore, the new bone which osseointegrated with the HA-coated implants has a possibility to remain for a long time.

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The aim of this study is to evaluate the clinical outcomes of transcrestal sinus floor elevation (TSFE) procedure using HA-coated implants without bone grafts. Using TSFE procedure without bone grafts or bone substitutes, 175 HA-coated implants were placed in the elevated sinus of 107 cases. The survey was performed on the cases with prosthesis restoration completed over a time period of 130 months from March 2004 to December 2014. All implants except one gained osseointegration. Five implant failures occurred in 4 cases after addition of occlusal force. Four implants were replaced in 3 failed cases, and all 4 implants gained osseointegration. In all 107 cases, no postoperative complication such as sinusitis, nasal bleeding or rhinorrhea was experienced. TSFE procedure using HA-coated implants without bone graft is highly reliable, predictable and less invasive. There is no risk of maxillary sinusitis induced by grafted bone’s migration into sinus cavity or infection by an unknown virus derived from the use of xenograft and allograft. After performing TSFE even on cases with small vertical bone height, replacement of failed implants is possible.

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