アブストラクト（30巻1号：神奈川歯学）

神奈川歯学

Japanese

Title　： 歯髄腔外における歯髄血流調節機構に関する形態学的研究
Subtitle　： 原著
Authors　： 酒井秀士, 高橋和人
Authors（kana）　：
Organization　： 神奈川歯科大学口腔解剖学教室
Journal　： 神奈川歯学
Volume　： 30
Number　： 1
Page　： 1-16
Year/Month　： 1995 / 6
Article　： 原著
Publisher　： 神奈川歯科大学学会
Abstract　： 「緒言」 歯髄は周囲を硬組織によって囲まれ, 唯一歯根尖孔を介して隣接組織と交通するきわめて特殊な環境下にある組織といえる. 言い換えれば, 歯髄は炎症の3大徴候の1つである腫脹がほとんどできない組織であることから, Heyeraas(1985), Kim(1985, 1986)は, このような歯髄をLow Compliance Environment下にある組織として, 身体の他の部位ではみられない特別な組織として位置づけている. 歯髄は外来性の物理学的, 化学的, または生物学的刺激によって局所に炎症を生じた時, 炎症の初期反応として血管壁の透過性亢進が起こり, また動脈口径の増大によって血流速度を上昇させ組織中にある起炎物質や炎症性の代謝産物等を歯髄腔外へ運び出そうとする. このことは歯髄を灌流する血流量の増大をまねき, さらに全体として歯髄組織内圧の上昇を引き起こす. しかし, 歯髄の炎症が局所に限定されている段階では歯髄内のU-turn loop構造が局所の血流量を調節し, 歯髄全体への影響を極力少なくするように働いている.
Practice　： 歯科学
Keywords　： 動静脈吻合, 血管鋳型法, 歯髄, 微小循環, precapillary sphincter

English

Title　： Regulation Mechanisms of Pulpal Blood Flow outside the Dental Pulp
Subtitle　： Original article
Authors　： Shuji SAKAI, Kazuto Takahashi
Authors（kana）　：
Organization　： Department of Oral Anatomy, Kanagawa Dental College
Journal　： Kanagawa Shigaku
Volume　： 30
Number　： 1
Page　： 1-16
Year/Month　： 1995 / 6
Article　： Original article
Publisher　： Kanagawa Odontological Society
Abstract　： Abstract : The dental pulp is surrounded by hard tissue except for the apical foramina communicating with the periodontal ligament and the alveolar bone. Therefore, the dental pulp would be considered as a specific, low compliance environment which is not found in any other places in the body. It is well known that the presence of arterio-venous anastomoses (AVA) and U-turn loops in the pulp cavity are morphological evidence of the control of pulpal blood flow. However, no papers have dealt with morphological evidence suggesting the presence of a control mechanism for pulpal blood flow outside the pulp cavity. This study was attempted to elucidate whether such a mechanism exists using the microvascular corrosion cast method with scanning electron microscopy (SEM). Twenty mature mongrel dogs with no caries or gingivitis were used for this study. The following special findings were obtained. (1) Vascular sphincters (VSph) were found in the periapical tissue. VSph were found in a "closed" state at branch points of arterioles that supplied the dental pulp. They could be distinguished three types : (1) Spiral type : The endothelial cells were arranged in a spiral and branch points of arterioles were twisted by the VSph. (2) Constrictive type : The endothelial cells were arranged straight and branch points of arterioles were constricted by the VSph. There were a few concavities noted at the vascular corrosion cast sites. (3) Intermediate type : This type had both spiral and constrictive characteristics. (2) AVA were found in the periapical tissue. AVA had two types of communication. One type of AVA were found between arterioles passing toward the pulp and venules in the periodontal tissue. Another type of AVA were found between arterioles passing toward the pulp and venules exiting the dental pulp. The AVA had a morphological character which was usually maintained in "closed" state. The projection of endothelial cells into the lumen was only observed at branch point of arterial side of the AVA. In conclusion, these findings suggest that the VSph and AVA are truly regulation mechanisms of pulpal blood flow outside the dental pulp.
Practice　： Dentistry
Keywords　： precapillary sphincter