アブストラクト（12巻3号：神奈川歯学）

神奈川歯学

Japanese

Title　： レッチウス線条の合致性に関する研究補遺
Subtitle　： 原著
Authors　： 更家佐, 山本勝一
Authors（kana）　：
Organization　： 神奈川歯科大学法医学教室
Journal　： 神奈川歯学
Volume　： 12
Number　： 3
Page　： 118-127
Year/Month　： 1977 / 12
Article　： 原著
Publisher　： 神奈川歯科大学学会
Abstract　： 「抄録」歯は死後永くその形をとどめていることが多いので, 法医学, 人類学などの領域では貴重な資料である. 文献によると, 「エナメル質の発育線であるレッチウスの線条は, 同一個体の左右同名歯および同一時期に発生したと思われる歯同士では, 線条の作る縞模様が同様になるはずである」とされており, また, 「約1年半以上同時に発育形成された異なった歯でも, 紋理は合致する」と述べられている. これらのことから, 従来, レッチウス線条の合致性が個人の識別に役立ち, 法医学的にきわめて価値が高いとされていた. しかしながら, 従来の研究者の業績を検討してみると, いずれも被検例数が少なく, 著者の経験上, それほど高い率で合致するとも思われないので, 以下のごとく再検討を試みた. 試料は11歳から83歳までの日本人男女から抜去された歯で, そのうちわけは, 前歯690歯(345組), 小臼歯336歯(168組), 計1,026歯(513組)である. これらの試料を約200μの研磨標本とし, 偏光顕微鏡にダイナスコープを取り付け, 倍率20倍で鏡検した. また, 被検歯が常にエナメル質を完全に保存しているとは限らないことから, 線条の合致性を検討するにあたっては, 前歯を6ブロック, 小臼歯を8ブロックに分けて, 部位別に観察した. 線条の合致, 非合致の判定は, 比較すべき2歯の線条の幅, および間隔の割合が, 複数以上なおかつ全体的にみて一致している場合を合致(+)とし, そうでない場合を非合致(-)とした. この結果, 以下の結論を得た. 1. 前歯群の同顎同名歯では, 上顎同名歯間および下顎中切歯間のAおよびBブロック(唇側切端に近い部位)において60～80%の合致率を示すが, 他の組合わせではどのブロックも合致率は低い. また, 前歯群の異名歯間では, AおよびBブロックにおいては約60%の合致率であるが, 他のブロックでは, 30%以下である. 2. 小臼歯群の同顎同名歯間では, Aブロック(頬側咬頭頂付近)における合致率は59%であるが, 他のブロックでは合致率は低い. 小臼歯の異名歯間では, その合致率はさらに低い. 3. レッチウス線条の合致性の有無についてブロック別に観察する場合には, 同一個体に由来する歯同士であっても, しばしば一致しない例があることがわかった. 4. 法医学的に個人識別を行うにあたり, とくにブロック別によるレッチウス線条による合致性については, 今後充分な考慮を必要とする.
Practice　： 歯科学
Keywords　：

English

Title　： A Supplement to the Agreement of the Retzius Incremental Striae
Subtitle　：
Authors　： Tasuku Saraya, Katsuichi Yamamoto
Authors（kana）　：
Organization　： Department of Forensic Medicine, Kanagawa Dental College
Journal　： Kanagawa Shigaku
Volume　： 12
Number　： 3
Page　： 118-127
Year/Month　： 1977 / 12
Article　： Original article
Publisher　： Kanagawa Odontological Society
Abstract　： As the teeth retain their shapes much longer after death, they are considered as a valuable material in the realms of legal medicine and anthropology, etc. According to the literature, Retzius incremental striae or lines that are seen on enamel prisms have more or less the same contour lines on the right and left homonymous teeth or those teeth supposed to have had the genesis at the same period. It is also maintained that the teeth, developed apart for more than a year and half, have the contour lines that will agree one with another. Based on these findings, the agreement of Retzius parallel striae has been regarded as possessing a high value in identifying individuals in legal medicine. However, the number of study subjects published in previous literature is far from sufficient. Moreover, experience of the author made himself suspect the rate of agreement as had been hitherto reported. For this reason, the author carried out the present study in which a total sample of 1,026 teeth (513 sets), consisting of 690 anteriors (345 sets) and 336 premolars (168 sets), extracted from the Japanese males and females. 11 to 83 years in age, were used. These teeth were prepared as polished specimens to the thickness of about 200μ and were examined by the polarized microscope, attached with the dynascope, at a magnification of X20. From the consideration that all these had retained no enamel substance in perfect conditions, the anteriors were divided into 6 blocks and premolars into 8 blocks for the purpose of sectional examinations. In determining the agreement or non-agreement of Retzius striae, those teeth whose width and ratio of their distance between a pair were judged to agree from overall viewpoint were rated as agreeing (+) and those teeth which did not fill these conditions were rated as non-agreeing (-). As a result of the study, the author obtained the conclusions as follows. 1. With the anterior homonymous teeth in the same jaw, a percentage of agreement was found to be anywhere from 60% to 80% between the upper homonymous teeth and between A and B blocks of the lower central incisors, the latter block being the portion near labial tips. In any other combination, the percentage of agreement was found to be low enough. Moreover, although there was seen about 60% agreement between A and B blocks of heteronomynous anteriors, an agreement between other blocks was less than 30%. 2. There was found a rate of 59% agreement in A block (the portion near buccal cusp ridges) of the homonymous premolars in the same jaw. In other blocks, the rate of agreement was low. Further, between the heteronomynous premolars the rate of agreement was found to be much lower. 3. It was clarified that disagreement of Retzius striae is frequently observable even between teeth from the same individual if the observation is done by blocks. 4. In the medico-legal identification by means of the agreement of Retzius striae in the enamel, thorough consideration is necessary if the method of examination by blocks is to be taken.
Practice　： Dentistry
Keywords　：