Fig.2 Headgear 
noises, the lens of cameras were covered with an infrared 
ray filter and the cameras were able to work in only infrared 
band. The ring strobe, which is attached to lens, emits 
synchronized infrared rays and the camera detects the re- 
flection of targets. These targets are covered with reflect- 
ing membrane, semispherical shape and 2 mm in diam- 
eter. A fast processor unit for shape recognition performs 
cross relation processing on the image signal sent from 
each camera, and recognizes the circular targets. Then 
the processor calculates the x and y coordinates of the 
marker centroid. This operation allows a remarkable in- 
crease of the resolution and precision because it can elimi- 
nate noises, which were background reflections. After it, 
the set of the markers is identified by manual, calibrated, 
and the 3-D coordinates of targets are worked out (Ferrigro 
& Pedotti, 1985). 
2.2 The Subject and the Test Foods 
The subject was a complete denture wearer (76 years 
old female). She wanted to have her dentures remade, 
because she couldn’t eat smoothly with her old dentures. 
She was free from any signs and symptoms of Clanio 
Mandibular Dysfunction. New complete dentures were 
made in the Department of Geriatric Dentistry, T.M.D.Univ. 
She was given informed consent to participate in this study. 
Before measuring, dentures were examined about their 
size, bite condition, occlusal height, shape of fringe and 
fitting. The five test foods (gum, carrots, fish paste, pea- 
nuts and cookies) were selected. The reason for this was 
that they had different textures and commonly used for 
studies. 
418 
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Fig.3 Difference of Standard Deviation of the Twnty-four 
Targets on the Grid Before and After Filtering 
[mm] 
© 
N 
e 
  
  
  
  
  
  
  
Clench 
Fig. 4 Three Phases of Mastication 
This is the horizontal movement of the chin. 
Open Close 
2.3 Measuring 
The measuring was done twice, before wearing the new 
complete dentures and after three weeks. She was in- 
structed to place each test food on their tongue and to 
masticate them on the unilateral side until they swallowed 
it. 
2.4The Targets 
During mastication, usually the head of the subject 
moves. To cancel the movement, the original headgear 
was used (Fig. 2). On the headgear, six control targets 
were attached in different places to adjust the movement 
and two rods on which two targets were attached each to 
indicate the mandibular condyle points. The marks on 
  
  
Fig. 5 A 
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