Finite element model based on a mandibular cast and a waxed complete denture: evaluation of the accuracy and the reproducibility of analysis.
OBJECTIVE
The purpose of this study was to evaluate a newly developed method to construct customized finite element models from the viewpoints of the accuracy of measurement and the reproducibility of calculated denture movement under loads.


METHODS
A cast of an edentulous mandibular alveolar ridge and a waxed complete denture were used. Measurement of the surface was done using a 3D-digitizer. After superposing, they were rotated so that the occlusal plane became level. The border of the alveolar ridge on the cast was decided in each buccolingual section. From a series of cross sections, the surface of the alveolar ridge was made. Based on the surfaces of the mucosa and denture, a finite element model consisting of the denture and underlying mucosa, which was given a uniform thickness, was constructed. This procedure and analysis under bilateral or unilateral loads on an artificial molar region were done repeatedly to evaluate its reproducibility and the error of the measurement of the surface.


RESULTS
The standard error of the measured shapes of spheres was estimated to be within 0.1mm. The error caused by superposing was estimated to be within 0.38 mm. The results of analysis showed that the coefficient of variation of the displacement of the denture at selected nodes was approximately 14.1% at most.


CONCLUSIONS
We conclude that this method has sufficient measurement accuracy and reproducibility for the calculated movement of dentures.
Takayama
Yoshiyuki
Y
Department of Oral Rehabilitation, Dental Clinical Division, Hokkaido University Hospital, Nishi-5, Kita-14, Kita-ku, Sapporo 060-8648, Japan. Takayama@den.hokudai.ac.jp
Sasaki
Hiroko
H
Saito
Masayasu
M
Sakaguchi
Kiwamu
K
Mizuno
Kentaro
K
Goto
Marie
M
Yokoyama
Atsuro
A