著者

飯島 裕之 山縣 健佑 北川 昇 張 仁彦

出版者

社団法人 日本補綴歯科学会

雑誌

日本補綴歯科學會雜誌 = The journal of the Japan Prosthodontic Society (ISSN:03895386)

巻号頁・発行日

vol.41, no.1, pp.61-70, 1997-02-01

参考文献数

23

被引用文献数

8

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Oral movement trajectories in a denture wearer were studied to evaluate masticatory capability by monitoring orofacial movements during mastication of a color-developing chewing gum. The subject was an edentulous patient who had 4 dental implants of the mandible to anchor a mandibular overdenture.<BR>To monitor the orofacial movements, a cordless light-emitting target that was recorded as a shining point with a clear outline when illuminated by a cold spot light was developed. An image processor enabled the recording and autotracking of multiple reference points.<BR>The subject chewed a new color-developing chewing gum that, on mastication, indicates the patient's masticatory capability using the intensity of red.<BR>During 250 strokes of chewing, the subject's face markers were recorded on a video tape by two high-speed TV camaras from two different perspectives, i. e., frontal and lateral. At the end of every 50 strokes, the color of the chewing gum was assessed by a Chroma Meter (CR-300, Minolta Co.), with respect to the degree of redness or a* value. Thus, the same chewing gum was continuously chewed for a total of 250 strokes, with the a* value measured at the end of every 50 strokes in 5 stages.<BR>Then, the video tape recordings of the start of the first stage (1F) and the end of each stage (1L-5L) were reproduced on a high-speed video and fed into an image processor (Image Data, ID-8000). The movements of each marker were automatically tracked by the Image Data, after which the resulting data of the 3-dimensional coordinates were fed into a computer.<BR>The trajectory of each monitored point during the 4 sec of each stage was computed by a 3-D analyzer (Movias 3D) with reference to the following parameters: the total length from start to finish of the trajectory (TL); the distance between the start and finish of the trajectory (SL); the ratio of the TL to the SL (T/S); the volume of the rectangular solid encompassing the entire trajectory (the cubical range); and the mean of the 3-dimensional angles that were created by differences in the direction of the preceding and following trajectories at each measured time (TH).<BR>Our results revealed that the time needed for one chewing cycle reduced gradually from 1F to 5L. Similarly, the TL of the incisal point (IP) and the THs of both the IP and the modiolus (Mo) also gradually reduced. These findings indicated that as mastication proceeds, the range of mouth movement becomes narrower and all the trajectories become smoother.

著者

澤田 久 山縣 健佑 張 仁彦 下平 修

出版者

Showa University Dental Society

雑誌

昭和歯学会雑誌 (ISSN:0285922X)

巻号頁・発行日

vol.16, no.2, pp.125-151, 1996-06-30

被引用文献数

9

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高速VTRシステムを用い, 顔面の運動経路を3次元解析した.画像処理装置によるオートトラッキングを行うための標点を作製し, 被検者顔面皮膚上に皮膚用粘着材で貼布した.被検者は, 上下顎無歯顎者3名, 被検音は, 短文「桜の花が咲きました」である.計測部位として, 鼻下点, 上口唇赤唇部上縁, 下口唇赤唇部下縁, モダイオラス部, オトガイおよび切歯点として下顎義歯の中切歯唇面からワイヤーを口腔外へ延長し, 標点を設けた.発音中の被検者の顔面正面と側貌を2台の高速テレビカメラ (nac社製) により高速ビデオカセットレコーダー (nac社製) で録画した.同時に, 音声を, 同一ビデオテープに録音した.得られた音声出力をDSP Sona-Graph (KAY社製Model 5500) に導入し, time-waveおよびスペクトログラム (3D Sonagram) から各音の発生および終了時点を求め, 解析対象区域を規定した.画像解析装置 (Image Data : ID-8000, nac社製) により解析対象区域間の各標点をオートトラッキングして自動解析し, 3次元座標を求め, コンピュータに転送し, 3次元運動解析ソフト (MOVIAS 3D, nac社製) を用いて立体構築した.解析項目は, (1) 空間的移動距離累計 (TL), (2) 計測区分開始点と終了点間直線距離 (SL), (3) TLとSLの比率 (TL/SL), (4) 立体移動範囲 (CR), (5) 方向変更角度 (TH) である.以上の結果, 下顎および各計測点の被検音全体の発音中の運動経路のTL, CR, THは, 無歯顎時 (A) より義歯装着時 (C) の方が小さいことが明らかになった.また, 被検音に含まれる他の母音および各子音の中で, /s/, /∫/, /m/発音中には, 特異の運動経路を示すことが認められた.