A Frontal Asymmetry Analysis JCO 1987
Since the advent of cephalometric radiography, orthodontists have focused on the lateral x-ray as their primary source of patient skeletal and dentoalveolar data. However, the frontal (PA) and basilar views also contain valuable information for diagnosis and treatment planning procedures. Various dental and skeletal widths and skeletal asymmetries that are not available from the lateral cephalogram can be quantified from a frontal radiograph (Fig. 1).
Orthodontists have traditionally been reluctant to use frontal radiographs for several reasons: difficulty in reproducing head posture; difficulty in identifying landmarks because of superimposed structures or poor radiographic technique; and concern about exposure to radiation. In addition, many clinicians have never been instructed in the use of frontal data.
Today more adult patients are being treated than ever before, with more sophisticated treatment goals. Identification of transverse and skeletal asymmetries from the frontal radiograph can be integrated with submental vertex and occlusal x-ray data (Fig. 2) to plan a multidisciplinary approach to adult treatment. Such frontal and asymmetry information is vitally important in:
1. orthodontic surgery planning (lateral and frontal VTOs);
2. differential tooth eruption with segmental TMJ splint therapy; and
3. functional jaw orthopedics including three dimensional improvements in facial or dental proportions or symmetry.