2001 Volume 55 Issue 1 Pages 47-62
The purpose of this study was to compare the magnitude and direction of displacement that arose in two groups of complete dentures when occluding unilaterally test food ; those for one group (FD, FG and FL) were made by flange techniques, which are generally said as showing an excellent stability during non-occlusal function like laugh and speech, while those for the other group (A) were made according to the law of the interalveoler ridge line, which shows an excellent stability especially during unilateral occlusion.
Eight edentulous patients (male : 3, female : 5, age : 74.9±8.1) whose oral mucosa, the function of tongue and temporomandibular joints were normal, were used in this experiment, and the displacement of complete dentures were respectively measured by using measurement analyzing system in six degrees of freedom.
The results obtained were as follows :
1) By utilizing this measurement analyzing system in six degrees of freedom, behavior analysis of the complete dentures could be gained easily and with accuracy.
2) When unilateral occluding tightly test food, every lower dentures tended to move toward the balancing side and lower-backward, and upper dentures except for FD the working side and upper-forward. Only the FD directed to upper-forward direction, and the molar region of the balancing side to lingual direction, and the frontal position rotatively moved to the working side.
3) To evaluate stability of the dentures, vertical displacement of the upper and lower dentures were respectively measured at the first molar of the balancing side when occluding unilaterally. The result was A>FG>FL in the upper and the lower dentures, but the vertical displacement of the only upper FD could not be evaluated with accuracy because it showed remarkable rotation and unstable equilibrium. Lower FL and FG were significantly smaller than FD (respectively p<0.05, p<0.01), and there was statistically significant association (p<0.05) between upper A and upper FL, too.
4) Vertical displacement ratio to the denture A was only one from some 0.65 to 0.85 in upper dentures and 0.75 in lower dentures, although one of lower dentures for the flange technique (FD) showed twice the ratio of the denture A.
5) The denture A did not show the most excellent stability in unilateral occluding tightly test food. It was therefore suggested that the dental molar arrangement method according to the law of interalveolar crest line, which was used in daily clinic, would be necessary for improvement.
On the basis of the foregoing findings, the linguarized occlusion was proved most effective in order to insure more excellent stability of complete dentures constructed by the flange technique.
