As the differentiation between true and pseudo-Class III cases is required for the orthodontic treatment, the present investigation were carried out to analyse the interrelation of the path of mandibular movements and also to examine the pattern of craniofacial association with mandibular movements.
Materials were consisted of the cephalograms and records of the path of mandibular movements which were taken from 20 Angle class III malocclusion cases, 10 cases (pseudo-Class III) well responded to the construction bite and the others (true-Class III) with skeletal problems.
The conclusion were as follows;
1) The retruded movement and the tapping movement, which was ended at the retruded tooth contact position, were observed in pseudo-Class III cases.
2) The inclination of the habitual jaw movement to SN plane was influenced by the inclination of the posterior border movement, and this tendency was more stronger in true-Class III cases than pseudo-Class III cases.
3) In pseudo-Class III cases, the inclination of the posterior border movement and habitual jaw movement to SN plane were significantly correlated with the antero-posterior position of the upper and lower jaw.
4) The analysis of interrelation of the path of mandibular movements to Condyle-Incisal plane inferred that the inclination of the retruded movement has a considerable effect on the inclination of the habitual jaw movement.
5) Pseudo-Class III cases seemed to be classified into two sub-groups, according to the variance of the horizontal component of the retruded movements.
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