4 方向から撮影したセファログラムを用いた顎顔面構造の三次元再構築  [in Japanese] Three dimensional reconstruction of maxillofacial structure by using four directions of cephalograms  [in Japanese]

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Abstract

頭部X線規格写真(以下, セファログラム)は歯科矯正学の分野で多くの分析や研究に用いられている.しかし, セファログラムには拡大と歪が存在すると多くの研究者が示唆している.この問題を解決するために, 正面と側面のセファログラムの2枚を用いて三次元再構築を行う方法が研究されてきた.しかし, 再現性と精度は臨床に用いるには十分でなかった.そこで本研究では, 正面, 側面, 左右斜位の計4種類のセファログラムを用いたシステムを新たに開発した.本研究では10体のヒト乾燥頭蓋を用いた.三次元再構築データはコンピュータによって求めた.計測点間の距離計測はスライディングキャリパーを用いて行った.本システムの信頼性を検討するために, 演算値と実測値の比較を行った.その結果, 本システムではゴニオンのような計測点の同定が容易で正確にできるようになった.そして高い再現性と精度が得られた.再現性に関しては, 標準誤差がX軸方向で0.01∿0.39mm, Y軸方向で0.04∿0.43mm, Z軸方向で0.03∿0.40mmであった.精度に関しては, 三次元再構築データと実測値の差は-2.13∿+2.36mmであり, 平均0.024mmであった.本システムを2症例に応用した症例を供覧し, 本システムが矯正臨床や研究で対象となる顎顔面部の構造を評価することの有用性を呈示した.

Cephalograms have been used for many analyses and studies in the orthodontia. But many investigators suggested cephalograms had the problems in magnification and distortion. To solve these problems, several studies on three dimensional reconstruction with posteroanterior and lateral cephalograms have been achieved. However, reproducibility and precision in these investigations were not enough to utilize. In the present study, we tried to design a new system by utilizing four directions of cephalograms, i.e., lateral, posteroanteriom, right-oblique and left-oblique cephalograms. Ten human dry skulls were used for this study. Three dimensional data were calculated by microcomputer. Linear measurements were done by the sliding caliper. Reliability on this system was examined by comparing the calculated distances to the actual linear measurements. As a result, some landmarks, such as gonion, could be identified easily and precisely. Then we could obtain higher reproducibility and precision. On the reproducibility, the standard errors were from 0.01 to 0.39 mm for X-axis, from 0.04 to 0.43 mm for Y-axis and from 0.03 to 0.40 mm for Z-axis. On the precision, the difference between the three dimensional reconstruction data and actual linear measurements was from -2.13 to +2.36 mm and average of difference was 0.024 mm. Therefore, this system could help us to evaluate the maxillofacial structure in the orthodontic clinics and researches. This strategy was applied to two cases.

Journal

  • 日本矯正歯科学会雑誌

    日本矯正歯科学会雑誌 53(4), 491-501, 1994

    日本矯正歯科学会

Cited by:  6

Codes

  • NII Article ID (NAID)
    110004013044
  • NII NACSIS-CAT ID (NCID)
    AN00187725
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • Data Source
    CJPref  NII-ELS  NDL-Digital 
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