β–リン酸三カルシウムによる担体を併用した歯の移植は骨と歯周組織再生を促進する

松本歯科大学大学院歯学独立研究科博士（歯学）学位申請論文;硬組織疾患制御再建学講座（主指導教員:各務　秀明教授

β-リン酸三カルシウムによる担体を併用した歯の移植は骨と歯周組織再生を促進する

緒言歯の先天性欠如の治療法として，他の治療法に対して，より高い機能性，審美性の向上，治療時間の短縮の利点により歯の移植の有用性が報告されている．しかしながら，移植床が歯の歯根幅に対し矮小な場合，適応外となる症例があった．そこで，本研究では歯の移植に合わせて不足する歯槽骨を再生させる事で，歯の移植治療の適応拡大を目指すことを目的として，移植された歯根周囲の骨再生に対するβ-TCPブロックおよび/または単核球（BM- MNCs）の影響を調査した，実験材料および方法移植歯と細胞のドナーとして，3週齢雄性C57BL/6Jマウスを用いた．上顎第一臼歯，上顎第二臼歯の抜歯を行い, 同系マウス大腿骨・脛骨の骨髄から， 密度勾配遠心法にてBM- MNCsの分離を行った．抽出したBM- MNCsは flow cytometryで分析した． 実験はMNC群，β-TCP群，Control群の3群とし，MNC群ではβ-TCP担体+MNC+歯, β-TCP群ではβ-TCP担体+歯，Control群では歯のみを6週齢雄性同系マウスの大腿筋内に移植した．移植4週間後に移植物を摘出し, 動物用マイクロCTにて評価を行った．標本は，HE染色，マッソントリクローム染色，およびOsteopontin(OPN)，Osteocalcin(OCN)，Periostin，type I Collagenに対する免疫組織染色をおこなった．再生組織の形態計測分析にはTRI/3D-BON（ラトック社）を用いた．結果抽出したBM- MNCsは，CD29 +/CD90+/CD45-細胞が0.5%であった．3群とも歯根周囲に骨再生を伴う歯周組織の再生が認められた．MNC群とβ-TCP群では，Control群と比較して，新生骨の骨組織体積（TV）， 骨体積（BV），骨表面積(BS)，ダイレクト計測骨梁幅（Tb. Th）とフラクタル次元が有意に大きかった（P<0.05）．また，MNC群とβ-TCP群では歯根の外側にも新生骨が認められたが，Control群では新生骨は外側での骨形成はわずかであった．新生骨は歯根周囲に限局していた．組織学的解析では，すべての群で未成熟な新生骨を示した．OPN陽性細胞，OCN陽性細胞は全ての実験群で新生骨の周囲に観察された．また，MNC群とβ-TCP群の根尖部は肥大したセメント質様組織が時折認められ，Control群では歯根外部吸収が認められた．歯根と新生骨間にはコラーゲンを含む歯根膜様の組織が形成され，一部はPeriostinおよびtype I Collagen陽性であった．この膠原線維は歯根表面に対して，MNC群，β-TCP群では垂直または斜走する線維だったが，Control群ではより平行な線維が観察された．また，全群で歯髄腔内に骨様構造の形成を認めた．考察β-TCPを用いた群ではControl群と比較して骨形成が促進されたが，このメカニズムとしてβ-TCPの骨伝導効果，多孔質構造による血管新生の促進，および骨再生のためのスペース確保が考えられた．新生骨量には，MNC群とβ-TCP群で差が見られなかった．分離されたBM-MNCsの中で間葉系幹細胞を含むCD29+/CD90+/CD45-分画はわずか0.5%であり，新生骨の形成の促進には細胞数が十分でなかった可能性がある．但し，Tb.Th，やフラクタル次元ではMNC群がβ-TCP群と比較し有意に大きかったことから，BM-MNCsは骨成熟を促進したと考えられた．移植した歯根と，新生骨間には歯根膜様組織の再生が見られたが，コラーゲン線維の走行やPeriostin， type I Collagenの発現から，再生歯根膜は正常な歯根膜と比較して未熟であった．歯周組織の成熟には機械的刺激が必要とされており，移植後の歯に対して負荷が無いことが原因と考えられた．2020博士（歯学）松本歯科大

A case of mandibular fracture including coronoid process fracture

The incidence of mandibular fractures is the highest among facial bone fractures. Addi-tionally, most of mandibular fractures occur in the mandibular angle and condylar process. On the other hand, the incidence of fracture of coronoid process is extremely low. We experienced a case of mandibular fractures involving mandibular body, condylar process as well as the coronoid process in a man aged 3₉–years–old who had received strong direct external force to the mandible. Mandibular fractures usually occur in the condylar process and mandibular angle because direct external force is more likely to transmit to these re-gions. Based on the classification of mandibular fractures, the incidence of mandibularfractures involving coronoid process increases with an increased number of fractures lines that means complicated fracture. At the viewpoint of anatomical portion, direct external force dose not transmit to coronoid process; however, it is possible that direct external force may transmit coronoid process in the case of complicated fracture. In this case report, we considered the potential mechanism of fracture of coronoid process by using a three–dimensional finite element model of a human mandible stress distribution analysis

Clinico–stastical study of outpatients and inpatients in the Matsumoto Dental University Hospital,for the last three years

Summary.The Matsumoto Dental University Hospital is located in the center of Nagano Prefecture and is the core hospital in the area.In this study,we carried out a clinicostatistical survey of outpatients and inpatients for the past 3 years.The number of outpatient and inpatients were 6,545 and 861,respectively,for the study period.The referral rate was 71.8%,which annually increased.The number of hospitalized patients by age was bimodal in their 20s and 70s.Dental diseases were most common in outpatients,followed by temporomandibular joint diseases,mucosal/skin diseases,and inflammatory diseases.Inpatients mostly had dental diseases,jaw deformities,inflammatory diseases,and cystic diseases.Moreover,410 cases used the operating room.Consequently,the number was annually increasing.Therefore,this study suggests that our department is functioning as a regional core hospital.However,building a medical care system that strengthens regional cooperation so that it can meet the various needs is necessary

B1 SOX Coordinate Cell Specification with Patterning and Morphogenesis in the Early Zebrafish Embryo

The B1 SOX transcription factors SOX1/2/3/19 have been implicated in various processes of early embryogenesis. However, their regulatory functions in stages from the blastula to early neurula remain largely unknown, primarily because loss-of-function studies have not been informative to date. In our present study, we systematically knocked down the B1 sox genes in zebrafish. Only the quadruple knockdown of the four B1 sox genes sox2/3/19a/19b resulted in very severe developmental abnormalities, confirming that the B1 sox genes are functionally redundant. We characterized the sox2/3/19a/19b quadruple knockdown embryos in detail by examining the changes in gene expression through in situ hybridization, RT–PCR, and microarray analyses. Importantly, these phenotypic analyses revealed that the B1 SOX proteins regulate the following distinct processes: (1) early dorsoventral patterning by controlling bmp2b/7; (2) gastrulation movements via the regulation of pcdh18a/18b and wnt11, a non-canonical Wnt ligand gene; (3) neural differentiation by regulating the Hes-class bHLH gene her3 and the proneural-class bHLH genes neurog1 (positively) and ascl1a (negatively), and regional transcription factor genes, e.g., hesx1, zic1, and rx3; and (4) neural patterning by regulating signaling pathway genes, cyp26a1 in RA signaling, oep in Nodal signaling, shh, and mdkb. Chromatin immunoprecipitation analysis of the her3, hesx1, neurog1, pcdh18a, and cyp26a1 genes further suggests a direct regulation of these genes by B1 SOX. We also found an interesting overlap between the early phenotypes of the B1 sox quadruple knockdown embryos and the maternal-zygotic spg embryos that are devoid of pou5f1 activity. These findings indicate that the B1 SOX proteins control a wide range of developmental regulators in the early embryo through partnering in part with Pou5f1 and possibly with other factors, and suggest that the B1 sox functions are central to coordinating cell fate specification with patterning and morphogenetic processes occurring in the early embryo