A comparative study was made of periodontal bone support and of tooth length in fifty-nine orthodontically treated patients with Class II, Division 1 malocclusion and sixty-one untreated persons of both sexes. Measurements of bone support and tooth length were made from ten-picture sets of intraoral radiographs taken with a standardized paralleling long-cone technique approximately 2 years after removal of the fixed appliances. The results demonstrated that persons who had received orthodontic treatment had significantly shorter teeth with less periodontal bone support than had the control subjects. For both parameters, the differences were most evident in the closed extraction spaces and in the maxillary anterior region.