口腔扁平上皮癌(OSCC)細胞株であるHSC3,HSC4およびSASの増殖に対するセツキシマブの影響を調べ,セツキシマブ感受性細胞と耐性細胞の特性を比較した.HSC3とHSC4の増殖はセツキシマブ感受性で,SASの増殖はセツキシマブ耐性であった.いずれの細胞もEGFRファミリーを介して増殖をするが,HSC3とHSC4の増殖にはEGFRが強く関与し,SASの増殖にはEGFRがほとんど関与しないことが示された.どの細胞もEGFRタンパク質を発現しており,明白な細胞表面局在を認め,リン酸化EGFRの存在も確認されたことから,セツキシマブ感受性はEGFRの膜表面への発現の有無ではなく,リガンド刺激に対するEGFR反応の方向性によって決まる可能性が示唆された.

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先進諸国において永久歯のう蝕経験は減少してきておリ,その理由の一つとして各種フッ化物応用の普及が指摘されている.しかし,う蝕経験には大きな世代間格差があリ,各世代においてフッ化物配合歯磨剤の市場占有率がう蝕経験の減少に対してどのように影響しているかは明らかにされていない.そこで,各世代のう蝕経験とフッ化物配合歯磨剤の市場占有率との推移について比較検討を行った.
  資料として,昭和32年から平成23年までの10回の歯科疾患実態調査およびフッ化物配合歯磨剤の使用占有率調査(ライオン(株))を使用した.昭和12年から平成13年生まれまでを5年間隔で11の世代へと分け,これを出生年コホートとした.歯科疾患実態調査が行われたそれぞれの時点における各出生年コホートの,50歳代までのDMFT指数およびDFT指数を算出しその時点に一致する年度のフッ化物配合歯磨剤の市場占有率と比較した.
  戦前から戦後すぐ生まれ世代では,30歳代以降DFT指数の増加が平衡状態への移行を示すのに対し,DMFT指数は直線的に増加していたが,これらの変化とフッ化物配合歯磨剤の市場占有率との間に関連は認められなかった.戦後から昭和30年代生まれの世代では,DFT指数およびDMFT指数がほぼ同じ時期に平衡状態に移行し,この時期はフッ化物配合歯磨剤の市場占有率が急増した時期であった.昭和40年代から50年代生まれの世代,および,昭和60年代以降生まれの世代では,DFT指数およびDMFT指数の推移に大きな差がみられず,前者ではその増加が平衡状態になる時期とフッ化物配合歯磨剤の市場占有率が50%に達した時期とがほぼ一致していた.以上の結果から,戦後生まれの世代におけるう蝕経験の減少は,フッ化物配合配合歯磨剤の市場占有率の影響を受けていることが示唆され,世代が若くなるに従って,平衡状態となったDMFT指数の値も低下していることが明らかとなった.

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補綴物と音声との関連を検討するために様々な音声分析機器を用いて研究が遂行されている.しかし,それらの機器は高価であること,操作が複雑であること,測定時に特別な部屋が必要なこと,および判定までに時間がかかることから,臨床においては実用的ではないのが現状である.
  そこで,発音機能と補綴物との関係の一端を検索するため,チェアーサイドで測定可能で操作が容易な連続音声認識ソフトのAmiVoice EX Dentalを用い,健常有歯顎の青年被験者を対象に厚さ1.5mmと3.0mmの実験的口蓋床を装着させた群と非装着群における歯科に関する書き言葉の音声誤認識率,およびオーラルディアドコキネシスを測定し比較した.
  その結果,各群別の平均誤認識率は,非装着群が3.5±0.9%,1.5mm群が4.8±1.6%.および3.0mm群が8.4±2.6%であった.床の厚みの増加に従い,平均誤認識率の上昇がみられ,各群間で有意差が認められた.また,オーラルディアドコキネシス値は/pa/における非装着群が6.6±0.9回,1.5mm群が6.3±0.9回,3.0mm群が6.5±0.9回,/ta/における非装着群が7.2±1.0回, 1.5mm群が6.8±1.0回,3.0mm群が5.9±0.9回,および/ka/における非装着群が6.7±0.9回,1.5mm群が6.2±0.9回,3,0mm群が5.9±0.9回であった.床の厚みが増すにつれて,全被験者に/ta/と/ka/の低下が認められ,非装着群と1.5mm群および3.0mm群間に統計学的な有意差が認められたことから,舌の運動抑制が考えられた.
  以上のように,連続音声認識およびオーラルディアドコキネシスの観点から検討した結果,実験的口蓋床の装着は音声認識率を低下させることが示唆された.

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保存修復学基礎実習の目的は,講義で得た知識の再確認と基本的術式の習得の場であり,使用する数多くの歯科用器材・器具,材料の取り扱いについても習得する場でもある.しかし,学生間の理解度には差が大きく,いかにして基礎実習内容を学生に習得させるようにするかは,常に悩まされるところである.本研究では,インストレクターの基礎実習教育へのフィードバックを目的として,学生の形成的評価も可能なOSCE形式での実習試験を行い検討した.平成20年度第3学年を2グループ(1班59名・2班58名)に分け,それぞれ2課題ずつOSCE形式の実習試験を行った.試験時間は,課題提示30秒,課題実施時間4分,移動時間30秒で行った.評価方法は,評価項目を設定し,できた:1点,できなかった:0点のチェックリストとした.
  今回,基礎実習終了試験をOSCE形式で行うことにより,インストラクターへのフィードバックが可能になると考えられる.今回の正答率の低い項目は,どれもファントーム内の顎模型上での操作もしくは手元での操作がほとんどであった.これは,基礎実習での学生13〜14人に1人のインストラクターのデモンストレーションでは,死角が生じ手先まではよく見えず,実習内容が理解しにくく,学生間に理解の差が生じ実習効果が期待を下回ることになると考えられる.いかに手元をわかりやすく学生に教育することが必要であると示唆された.
  一方で,繰り返し実習をした項目については正答率が高かったことは,従来から指摘されているように学生教育には反復が重要であることが示唆された.以上のことから,基礎実習における学生の理解度は,OSCE形式の実習試験により有効的に評価できること,また,デモンストレーションで理解しにくい手元で煩雑な操作は,学生の理解度が低いので,学生の理解度を高めるには,繰り返し教育することの重要性がわかった.

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We prepared a novel LED curing light with an Ml-head and a small tip of 2.1 mm capable of irradiating light close to the gingival wall. This new light was then compared with a conventional LED light curing unit, the Pen Cure, to investigate the influence of the curing unit on adhesion applied to the gingival wall of class II cavities. We investigated the tensile bond strength (TBS), marginal leakage and light intensity. We found that improvements in the irradiation method and prolonged irradiation are necessary to achieve adequate bond strength of the bonding agent to class II cavities when using the MI-head.

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We evalvated the ablation efficiency of the Er: YAG laser using a new test tip that sprays the irrigation fluid as a mist. The tip was prepared by modifying the conventional irrigation mechanism with the cooperation of the J. Morita Corp. The ablated cross-sectional area was significantly greater in the mist spray group than in the controls at an irradiation distance of 0.5 mm in enamel and at 0.5 and 1.0 mm in dentin. Spraying the irrigation fluid as a mist during laser ablation of dental hard tissue improved the ablation efficiency.

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Inflammatory cytokines such as tumor necrosis factor-α (TNF-α) were previously shown to be secreted in pulpitic tissue during the caries process. Matrix metalloproteinases (MMPs) such as MMP-1, 2, 3, and 14 were also shown to be expressed in inflamed dental pulp. Dental pulp destruction may be regulated, in part, by MMP-3. In addition, other MMPs activated by MMP-3 have been shown to regulate the degradation and regeneration of dental pulp. Ras-related C3 botulinum toxin substrate 1 (Rac1) is a pleiotropic regulator of many cellular processes, including cell growth, cytoskeletal reorganization, and the activation of protein kinases. We hypothesized that Rac1 may negatively regulate the production of MMP-3 from human pulp fibroblasts.

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During orthodontic therapy, osteoclast precursors such as monocytes and macrophages migrate from vessels into the periodontium and then differentiate into osteoclasts, causing bone resorption. Vascular cell adhesion molecule-1 (VCAM-1) is bound to very late antigen-4 (VLA-4) which is a kind of α4 β1-integrin. It recruits monocytic osteoclast progenitors and elevates local osteoclast activity. We focused on how VCAM-1/α4 integrin mediates the differentiation into osteoclasts and found that it was through FAK. Neutralizing antibodies against integrin α4 effectively inhibited the differentiation into osteoclasts and the phosphorylation of FAK. These findings confirmed that VCAM-1 regulates the differentiation of bone into osteoclasts.

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Dental treatment fees are regulated by the Japanese universal public health care system. However, it has been reported that there are differences in dental treatment expenditures between high and low income groups. We analyzed the current government data from a survey on family income and expenditures to investigate how income affects expenditures for dental treatment. We found that people with high income tend to spend a greater percentage of their total expenditures for medical and dental treatment on dentistry than do people with lower income. We would like to investigate how this gap can be reduced.

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We analyzed the relation between the number of missing teeth (MT) and the rate of market share of fluoride containing dentifrice (FRMS) by birth year cohort. We analyzed the date of 10 Japanese National Surveys of Oral Health between 1952 and 2011. The data for MT in those born from 1926 to 1973 were divided into 8 groups, one for each six year interval. The changes in MT and FRMS were analyzed for each birth year cohort. We found that MT increased with age, and that FRMS was lower in the earlier surveys. We found that the decrease in MT correlated with the increase in FRMS. These results suggest the goal that 80-years-old Japanese should have at least 20 teeth will be accomplished within 15 years.

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Titanium surfaces play an important role in affecting osseointegration of dental implants. Previous studies have shown that the titania nanotube promotes osseointegration by enhancing osteogenic differentiation. Only relatively recently have the effects been investigated that titanium surfaces with other nanostructures have on osteogenic differentiation. In this study, we used NaOH solutions with a concentration of 2.5, 5, 7.5, 10 and 12.5 M to develop a simple and useful titanium surface modification that introduces the nanonetwork structures with titania nanosheet (TNS) nanofeatures to the surface of titanium disks. Using different alkaline concentrations, we evaluated the effects of the modified nanonetwork structure on the osteogenic differentiation of rat bone marrow mesenchymal stem cells (BMMSCs). The nanonetwork structures with TNS nanofeatures induced by alkali etching markedly enhanced the BMMSC functions of cell adhesion and osteogenesis-related gene expression. In addition, it significantly increased other cell behaviors such as proliferation, ALP activity, ECM deposition and mineralization. These effects were most pronounced when the concentration of NaOH was 10M. These results suggest that nanonetwork structures with TNS nanofeatures improve BMMSC proliferation and induce their osteogenic differentiation. In addition, the surfaces formed with 10 M NaOH seem to have the potential to improve the clinical performance of dental implants.

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We studied the cell survival and gene expression of three-dimensional in vitro human periodontal ligament-like tissue (HPdLLT) under various compressive stress conditions mimicking orthodontic force. HPdLLTs were subjected to 5, 15, 25, and 35 g/cm^2 compressive stress for 1, 3, 7 or 14 days. Similar extracellular matrix, spindle-shaped cells and its survival inside or on the surface of each in vitro HPdLLT with no relation to compressive stress duration or intensity. Genes showed their distinctive expressions according to compressive stress duration or intensity. This study indicated that in vitro HPdLLT effectively mimicked the reaction and gene expression of human PDL in response to orthodontic force.

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We evaluated the effects of synthesized collagen model polypeptides that consist of a proline-hydroxyproline-glycine (poly (PHG)) sequence combined with porous alpha-tricalcium phosphate (α-TCP) particles on bone formation in a canine tibia defect model. Micro-CT analysis showed the volume density of new bone was higher in the poly (PHG)/α-TCP group than in the group with poly (PHG) alone at 2 and 4 weeks. However, there was no difference at 8 weeks. Histological evaluation at 4 weeks after implantation revealed that the poly (PHG) had degraded and newly formed bone was present on the surface of the α-TCP particles. At 8 weeks, continuous cortical bone formation with Haversian structures covered the top of the bone defects in both groups.

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Interleukin-17A (IL-17A) is produced by leukocytes such as Th17 cells, γδT cells, and natural killer cells. IL-17A stimulates osteoclastic bone resorption via osteoblasts by inducing the expression of the receptor activator of NF-κB ligand (RANKL). However, little is known about the direct effects of IL-17A on the osteoclast precursors. We examined the role of IL-17A on osteoclast differentiation of RAW264.7 cells. We confirmed that IL-17A and SP600125 directly inhibit differentiation of osteoclasts, which was stimulated by RANKL. We found that IL-17A reduced JNK phosphorylation and c-Fos expression, which were enhanced by RANKL stimulation. These results suggest that JNK and c-Fos are involved in the inhibition of differentiation by IL-17A stimulation.

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The purpose of this study was to analyze the relationship between dental caries prevalence and the market share of fluoride toothpaste by birth year cohort. The dental caries experience was obtained from 10 Japanese national surveys of oral health over about 60 years. The market share of the fluoride toothpaste was researched by the Lion Co., Ltd. It was analyzed by birth year cohort for 11 groups evaluated every five years. DFT and DMFT indices tended to peak for the generations born after World War II, while the market share of fluoride toothpaste also increased rapidly at the same time. The decrease in caries experience was likely affected by the market share of the fluoride toothpaste.

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