Abstract
Articulator movement and mandibular movement are usually regarded as rigid body movement. When we observe the three-dimensional movement of an articulator to which some targets are fixed, we obtain the co-ordinate (X, Y, Z) of each target in the rectangular coordinate system on a measuring apparatus. As accidental error is contained in each value, any distance between targets, which should be constant, is slightly changed on the observational occasion. Namely, the rigid body condition is not satisfied. The method of least squares is useful to correct accidental errors and give us desirable result of observation as the most provable value.
In this article, we investigate to correct accidental errors by means of the indirect observation of the method of least squares. When we correct accidental errors by using this method, we get the position (Xo, Yo, Zo) of the point, which is the translational and rotational center of the articulator, and three rotational angles (Ε, Φ, Ψ) as the most probable value. Using these values, we are able to analyze the movement of any point on the articulator: We can obtain the translation and rotation of teeth on the articulator.
