Prevalence of tooth agenesis correlated with jaw relationship and dental crowding.

Two groups of patients were selected from the State University Dental School in Ghent--an experimental group with tooth agenesis and a control group with complete dentitions. Skeletal anomalies were diagnosed by means of lateral cephalograms according to the Sassouni analysis. The amount of crowding was measured on standardized photographs by Little's Irregularity Index. The prevalence of Class I skeletal relationship appeared to be significantly higher in the agenesis group than in the control group. Skeletal deep- and normal-bite cases occurred more often in patients with hypodontia than in the control group. As far as crowding was concerned, it was less pronounced in the hypodontia group (lateral segments) than in the control group. This conclusion held true only when the "amount" of crowding was not taken into account.