This study demonstrates the importance of X-rays of the hand in assessing skeletal changes in jaw relationships. The study is based on a follow-up examination of 53 patients with skeletal class II,1-, skeletal class II,2-, class III and skeletal open bite malocclusions who had been treated orthodontically. Statistical analysis of the growth parameters found a significant correlation between chronological age and skeletal age with considerable deviations depending on sex. At the end of the treatment period it was observed that 34% of all patients had not reached the end of puberty and had not achieved a mature level of growth. During the post-therapeutical period, growth was found on average to be 2.4% in the girls and up to 4.7% in the boys. When looking at the influence of growth and therapy, the patient group with skeletal class II,1 malocclusion exhibited at both therapeutical and post-therapeutical examinations a very positive development both in the horizontal and vertical basal relation of the jaw with a significant increase in mandibular length and in anterior lower facial height. On the other hand the class II,2 cases exhibited significantly reduced lower facial height, which can probably be considered to be a causal factor in the 70% relapse rate after completion of orthodontic treatment. In class III malocclusions the horizontal jaw relationship was stabilized throughout the orthodontic treatment period, however, following treatment a progressive alteration became apparent. The results achieved in this study add weight to the importance of taking skeletal maturation factors into consideration in patients with skeletal jaw discrepancies. These factors are useful in prognosticating the therapeutical goal to be achieved, the degree of stability during treatment, and the chances of relapse following treatment.
