iPS細胞が登場する以前から再生医療の期待が高かったのが，体性幹細胞（組織幹細胞）である．その特徴は，患者自身から細胞の入手が可能であり，なおかつがん化・腫瘍化のリスクが低いことから，近年とくに取り沙汰される“医療の安全”には欠かせない幹細胞であることだ．なかでも，抜去歯から得られる歯髄の幹細胞は，子供から大人まで幅広く得ることができ，硬い歯の中に存在するので保存状態がよい幹細胞として知られている．そこで近年，治療抜歯した歯から歯髄細胞を培養して凍結保存し，将来の再生医療に活用する「細胞バンク」の取り組みが始まっている．本編では，がん化・腫瘍化のリスクがなく，医科・歯科共通の幹細胞ソースとしての歯髄幹細胞の魅力と，将来の再生医療をになう細胞バンクの取り組みについて概説する．

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The aim of the present review was to analyze the efficacy of powered toothbrush on clinical parameter in patients with dental implants. Recently two types of powered toothbrushes are available, namely, oscillating/ rotating powered toothbrush and sonic powered toothbrush. Some controlled studies revealed that oscillating/ rotating electric toothbrush or sonic powered toothbrush was found to be superior to the manual toothbrush in reducing plaque and inflammation around implants. Other studies suggested that comparable efficacy of the powered tooth brushes and manual toothbrushes with regard to plaque and bleeding scores. However, no study demonstrated that effect of powered toothbrushes were inferior to that of manual toothbrushes. Furthermore, any advance events did not report with the use of both type of powered toothbrush. Therefore, powered toothbrushes are recommendable to use in patients with dental implants as alternative to conventional manual toothbrushes. Further studies are required to determine the relative effectiveness of manual and powered toothbrushes in improving the status of patients with dental implants.

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An implant overdenture (IOD) with a few implants as an abutment can improve not only the oral function but also the clinical effectiveness for esthetics, cleanability, and changeability as compared to a fixed implant prosthesis. It is possible for elderly patients with declining self-sufficiency to have difficulty caring for their own implants when in their home or the hospital; therefore, a removable denture has to be considered as an alternative to an implant fixed prosthesis. The functions and denture movements of the IOD change remarkably depending on the location, number of implants, direction of implant placement, and attachment selection. Recently, the application of implant assistants has contributed to movement toward an implant removable partial denture (IRPD), leading to increasingly diversified outcomes. This paper outlines reasons to reconsider choosing an IOD, the fundamental approach necessary for IOD success, and ways to maintain and treat complications of IOD and select attachments. Key words: implant overdenture, attachment selection, maintenance, trouble shooting, survival rate

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歯科における近未来における治療テクニックの革新提案です．今回提案したいくつかの技術は必ずしも歯科医療分野ではないが、未来の歯科医院の大きな発展を目指して以下の項目を提案する．1）突然死防止や糖尿病患者などの救急用として、人工歯内の空洞内の装置から体内に緊急に薬を注入する自動薬剤注入システム．2）補綴物に入れるタバコ．3）根尖病巣などの難治症例で光毒性を活用した治療法の開発．4）DentureCameraを使用した目の代替法の開発．5）歯や義歯の空洞活用情報システムである．

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近年，ライフステージに応じた口腔機能管理の重要性が問われている．特に無歯顎者の「噛めない」「食べられない」と言った“食”に関する問題は切実である．このような問題に対し，口腔機能，とりわけ咀嚼機能の回復は義歯治療（有床義歯補綴治療）が主体をなすことが一般的と言え，それを担う多くの職種の中でも歯科が果たす役割は大きい．義歯治療の成否は患者の“食”の問題を大きく左右する．そのため義歯には“安定した咀嚼”を行いうる機能が具備されていなければならないのは当然である．しかし“安定した咀嚼”を客観的・定量的に評価する確立された手法は存在していない．義歯治療による機能回復の程度や様相を知ること，言わば義歯装着者の咀嚼機能評価は，義歯の挙動変化を示す“不安定に対する評価”に，食への“安定に対する評価”である咀嚼能力をも評価されるべきであり，さらには実際に使用する患者の意見をも反映した患者満足度も含めた評価が望まれる．しかし従来の義歯装着者の咀嚼機能評価は咀嚼“能力”に主眼が置かれ，咀嚼“機能”を十分に評価することは困難であった．これまで著者らは，臨床の現場で全部床義歯治療における“不安定に対する評価”に重点を置いた義歯の機能時・満足度の評価や，被検食品を用いた咀嚼の評価を行っており，“安定した咀嚼”を得るために奮闘してきた．今回，これら義歯の機能評価法と咀嚼機能評価法とを統合し，新たにThe Apple Scale として体系化したため，その概要について報告するとともに，インプラントオーバーデンチャー装着者の治療結果評価への適用を試みたところ興味ある知見が得られたため報告する．

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Spherical porous hydroxyapatite was synthesized by a wet method using a simulated body fluid. The grain size is about 1 - 5 μm, the center part is dense, but there are plate - like crystals of about 0.1 - 0.5 μm overlapping on the surface, and there is a gap of about 0.4 μm at the maximum therebetween . We evaluated the oil adsorption ability and light reflection properties of spherical porous hydroxyapatite and investigated further possibilities of application as pharmaceuticals and cosmetics. When tri (caprylic / capric acid) glyceryl, sugar squalane and oleic acid were investigated, the adsorption amount of fat was almost the same as that of commercially available apatite. It is thought that oils are held mainly in the gaps of plate crystals. Light reflection in the near infrared region is about 60% higher than that of particulate apatite produced by the same manufacturing method, and it can be expected to be applied as biomaterials and cosmetic materials for protecting the skin from near infrared rays. Furthermore, since spherical porous hydroxyapatite can also carry functional particles in gaps or the like of plate crystals, further possibility is suggested as a multifunctional material.

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Purpose: Full thickness oral mucosal defects are common following resection of various oral mucosal lesions such as oral cancerous or precancerous lesions. Our laboratory investigated cell sheet technology to overcome the unmet medical needs. In this study, we evaluated the feasibility of tissue-engineered gingival mesenchymal cell sheets for treating palatal full thickness defects in rats. Materials and Methods: Gingival mesenchymal cells were obtained from mandibular attached gingival tissues of EGFP rats and cultured. Cells were cultured using thermo-responsive culture dishes to form cell sheets for transplantation onto palatal full thickness defects (3mm in diameter) of SD rats. Six rats were divided into two groups, a transplant group and a control group. Three animals were used in each group. After the cell sheet was transplanted, macroscopic images of palatal wound were taken until complete wound closure. Wound area was analyzed using Image J software. Results: The cells exhibited colony forming potential and formed calcified nodules when they were cultured in osteoinductive medium. Wound healing was accelerated when the cell sheet was transplanted at 3.3 ± 0.6 days (mean ± SD) postoperation in the test group. In the control group, healing was accelerated at 4.7 ± 0.6 days after the transplantation. The palatal full thickness defects were well-regenerated, and wound healing in the transplant group was completed at day 6.6 ± 0.6. In contrast, wound healing in the control group was completed at day 8.6 ± 1.2. It was statistically significant difference between two groups. Histological examination showed similar wound healing patterns in the two groups. After using H.E. staining, dense hyperplasy of the connective tissue is detected in the transplant group compared to the control group. Conclusion: Gingival mesenchymal cell sheet can be served as a new reconstruction material for palatal full thickness oral defects.

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Purpose: Various maxillary sinus floor elevation techniques are used together with augmentation procedures for oral rehabilitation. Dental implants with or without bone substitutes or autologous bone grafting, and applied using the lateral window technique or the transcrestal osteotome-mediated sinus floor elevation technique, are used to enhance bone stability for implant installation. The aim of this study was to retrospectively evaluate the implant status of patients who had undergone maxillary sinus floor elevation and immediate or delayed implant placement via such techniques, with or without graft materials. Materials and Methods: In total, 398 dental implants placed in 169 maxillary sinuses of 169 patients (106 females, 63 males; mean age, 57.5 years), who were fitted with Astra Tech dental implants, and required maxillary sinus floor elevation, were evaluated in terms of the amount of residual bone remaining following treatment; the residual bone was assessed by elevation technique subgroup. The vertical height of the residual maxillary alveolar bone and the augmented vertical bone height were analyzed using digitalized panoramic radiographs. Clinical and radiological follow-up was carried out over a period of 120 months after functional loading of a fixed prosthesis. The mean follow-up period was 55 months. Results: In total, 277 implants, with a mean residual vertical bone height of 3.72 mm, were installed in 113 maxillary sinuses using the lateral window technique. Of these, 216 implants (mean vertical bone height, 4.87 mm) were installed in 96 sinuses simultaneous with sinus floor elevation using β-tricalcium phosphate (βTCP) using no graft material or intraoral autologous bone. The remaining 17 sinuses underwent 61 implants (mean vertical bone height, 2.57 mm) according to a delayed installation schedule using βTCP or iliac autologous bone. In 56 sinuses, 121 implants (mean vertical height, 8.60 mm) were installed simultaneous via the transcrestal osteotome-mediated technique with βTCP. Although seven implants failed (three early and four late failures) over a follow-up period of 120 months (mean follow-up, 55 months), the other implants remained stable, with a high survival rate of 98.2%. No elevation technique or graft material subgroup showed any statistical significance, and complications were minimal. Conclusions: The findings of this study demonstrate that various maxillary sinus floor elevation techniques for implant installation, with or without graft material, are safe, having low complication rates and yielding predictable results.

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Purpose: Because of its high water capacity and ability to maintain its volume, bacterial cellulose (BC) might be suitable as a sustained-release carrier of BMP-2. This was examined in a rabbit frontal sinus model. Materials and Methods: After moving the bone wall, the sinus membrane was reflected using a mucosal elevator in rabbits. There were three experimental groups: Group A underwent BC grafting only; group B was grafted with BC soaked with BMP-2 (5 μg); and Group C was treated with BMP solution only. Two rabbits in each group were sacrificed at 4 and 8 weeks and tissues sections were stained with hematoxylin-eosin and observed under a light microscope. Result: BC retains its 3D structure histologically. Marked new bone formation was observed along the BC only in group B, treated with BC soaked with BMP-2. Conclusion: The sustained release of BMP-2 from BC has positive effects on bone formation, and it might be developed as a carrier to promote clinical bone formation.

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Introduction: Periosteum plays important roles in bone regeneration. High biocompatibility of titanium coated with hydroxyapatite (HA), favoring the bone regeneration, has been reported. The aim of this study was to evaluate the subperiosteal bone formation on titanium plates coated with or without hydroxyapatite. Materials and Methods: Six Japanese white male rabbits, 20 weeks old, were used. Titanium plates (5 x 5 x 0.5mm) coated with or without HA (1 μm thickness) were prepared with a spattering method. Titanium plates with or without HA were inserted subperiosteally on the right or left side of the calvaria and the tibia, respectively. Four weeks after the surgery, the specimens were examined with a high-resolution microcomputed tomography (CT) imaging system and histologically. Results: On the tibias, more bone formation was observed on the HA-coated titanium plates than the titanium plates without coating whereas there was no significant difference of bone formation between the two titanium plates on the calvaria. Conclusions: Although HA-coated titanium plates favorably stimulated bone formation under the periosteum of the tibia, response of periosteum to HA-coating is different between calvaria and tibia: The periosteum of the tibia has more osteogenic ability than the one of the calvaria.

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Octacalcium phosphate (OCP) precipitates on diopside in simulated body fluid. We investigated to remove the phosphate in solution containing phosphate by using this precipitation reaction. By immersing diopside sintered at different temperatures in a 100 μmol/L phosphate solution, it was found that the diopside sintered at 650ºC yielded a removal rate of 91.1% and removed a large amount of phosphate. Surface observation of diopside after the removal of phosphate confirmed the presence of precipitates on the surface. Further, X-ray diffraction analysis of diopside immersed in a 10 mmol/L phosphate solution showed a peak near 32°, which was considered to originate from OCP. This is presumed to be due to the superior OCP precipitation ability by adsorption by surface hydroxyl groups and consumption of phosphate. From the results of this study, it is expected that the synthesized diopside is excellent for phosphate removal and is thus useful as a phosphate-removing material.

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Purpose: Periodontal disease is a chronic inflammatory disease that affects the periodontal supporting tissues of teeth. The aim of this study is development of a new local drug delivery system (LDDS) containing salicylic acid (SA) or metronidazole (MTZ) to apply in a dental intra- pocket for periodontitis treatment. The new dental pocket drug delivery system (DPDDS) can be easily administrated by the periodontitis patient, the oral tissues can be return and maintained to a healthy state, so it is useful as a non-surgical local therapy. Methods: The filaments were prepared by physical mixing of 10 wt% of hydrophilic drug (SA) or hydrophobic drug (MTZ) with different kinds of polymers including Soluplus® (SP), and Hydroxypropyl cellulose (HPC). Then the filaments were fabricated by the hot melt extrusion (HME) method. We obtained a filament with two kinds of shapes in the same weight which are 10 mm length/500 μm diameter and 1.5 mm length/1500 μm diameter. Both SA and MTZ were release from filament in simulated saliva was determined by UV-spectrometer. The scanning electron microscope (SEM) was used for observed the shape and determined the distribution of the drugs on the surface of the filaments. Results: According to in vitro study, the mechanism of drug release which followed Korsmeyer-Peppas kinetics model mostly indicated anomalous (non-Fickian) diffusion. While release kinetic profile which explained the drug release rate was followed Higuchi’s kinetics model. The results shown SP made drugs release faster than HPC. Comparison between short/thick and long/thin filaments containing MTZ showed the short/thick had slower MTZ release than long/thin filament. The SEM images shown some particles of drug distributed thoroughly filament which confirmed a solid dispersion dosage form. Conclusion: These results suggested that filaments of SA and MTZ could be applied for periodontitis treatment using this DPDDS.

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現在の歯科インプラントは，インプラント周囲炎が，大きな問題となっている．インプラント周囲炎の対策として，アバットメント部と歯肉との接着性の向上を目指し，Si含有リン酸カルシウム薄膜をTi上にコーティングし，作製した薄膜の細胞接着性を評価した．細胞接着数の結果から，各試料の観察面積あたりの細胞核数は，Si含有量の増大とともに，細胞接着数が増大し，SiO2-30で46（個/frame）と最大を示した．さらにSiが増大すると接着数が減少し，SiO2-100で24（個/frame）となった．また，SiO2-50では24（個/frame）となり，SiO2-100と同数の低い接着数となった．今回，Tiに比べ，Si含有リン酸カルシウム薄膜は，細胞接着性が高い傾向が見られた．SiO2系ガラスにCaやPを含有させた結晶化ガラスは，歯肉との接着性が良いことが臨床的に確認されているため，今回のSi含有リン酸カルシウム薄膜においても良好な結果が得られたのだと考えられる．

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