[Verification of precision by 4-dimensional analysis of mandibular movement].
OBJECTIVE
The 4-dimensional human body model that combines reconstructed 3-dimensional image data (CT and MRI) and exercise data of the human body is widely applied in the medical field. We have applied this technique to assess mandibular movement, particularly in dentistry, and developed a 4-dimensional system of analyzing mandibular movement. The aim of this study was to determine the accuracy of this analysis system.


METHODS
A dry skull mandible was fixed at several mandibular positions and the skull-mandible relationship was measured at each position by two procedures: CT scanning was performed and a 3-dimensional image was reconstructed from image data that were regarded as true values; then, optical measurement markers attached to the dental arch were measured 3-dimensionally and calculated as positional measurement values. The measurement values were compared with the corresponding true values to identify measurement errors of the analysis system.


RESULTS
The root-mean-square (RMS) errors of the 4-dimensional analysis system of mandibular movement were, on average, 0.41 mm and 0.43 degrees.


CONCLUSIONS
These findings suggest that our 4-dimensional analysis system has sufficient measurement accuracy for mandibular movements.
Ogawa
Takumi
T
The Second Department of Prosthetic Dentistry, Tsurumi University School of Dental Medicine, Tsurumi, 230-8501, Kanagawa. ogawa-t@tsurumi-u.ac.jp
Shigeta
Yuko
Y
Ando
Eriko
E
Suma
Mayumi
M
Fukushima
Shunji
S
Otake
Yoshito
Y
Hattori
Asaki
A
Suzuki
Naoki
N
Kobayashi
Kaoru
K
Mishima
Akira
A