[Intellectual development in cases with normal occlusion and malocclusions]

Purpose of this study is to evaluate psychical maturity of two orthodontic groups of examinees. Sample consists of 640 children: 320 are (E) orthognathous (160 girls and 160 boys) and 320 are (PS) dysgnathous (160 girls and 160 boys). They are classified according to their age (7-14 years) into 32 groups, 20 examinees each. The dysgnathous subjects have a specific malocclusion; early tooth loss or secondary crowding. The evaluation of psychical maturity is based on the general success in school and the results of the intelligence test of the "Raven's Progressive Matrices", both are expressed in points. The results are statistically treated and presented in tables and graphs. PS children, in the analyzed sample, develop psychically slower than E children. PS examinees have lower score (in points) of general success in school, as well as in results of the intelligence test. Although the difference in the arithmetic means obtained by the results of the intelligence test between E and PS subjects is statistically significant, (t = 6.76; P = 0.009), clinically it is not considered significant and it is not interpretable, (as when expressed in points it amounts to only two points).