Abstract
Fifty-four mandibular prognathism patients seeking surgical correction underwent psychological evaluation using MMPI before the operation.
The results are as follows:
1. There was no personality deviation which commonly characterized the personality of a mandibular prognathism patient.
2. Eighteen (33%) of the subjects exhibited some deviation of personality demonstrated by high T scores (more than 65) on several clinical scales of MMPI.
3. The relationship between the degree of facial deformity measured with the quantity of over-jet and the T scores of MMPI scales was evaluated. The results showed that the minimal deformity group and the largest deformity group were inclined to have high T scores on several clinical scales of MMPI. The results also indicated that there was no correlation between the degree of deformity and the deviation of personality.
4. The greater the ratio of the degree of suffering from the facial deformity to the degree of over-jet, the greater was the occurrence of patients with remarkable deviation of the personality. It was also shown through multiple regression analysis that the Sc scale had large positive weight in the prediction of the ratio taking into consideration the standard partial regression coefficients (STB) of each scale.
5. In fourty-five subjects, there were twelve cases of patients who exhibited problematic behaviour during the course of treatment of their deformity. They tended to be suffering a great deal psychologically although their facial deformity was less than average. The multiple regression analysis showed that the Pd scale, the D scale and the K score of MMPI were very accurate in predicting problem patients. The higher the score of the Pd scale and the D scale, the more troublesome the patient was. On the other hand, the higher the score of the K score, the less troublesome the patient.
6. The frequency of the occurence of problem patients was higher in male patients than female patients. A great deal of attention should be paid to the psychological aspect of male patients in the surgical treatment of mandibular prognathism.
