Harmonic analysis of mandibular form and symmetry with computerized tomographic views

OBJECTIVE: To quantitatively describe the isotropic (ie, orientation independent) morphologic characteristics of a standardized computed tomographic image of the mandible with the use of the elliptic Fourier series. STUDY DESIGN: Spiral CT scans parallel to the mandibular plane and enclosing both mental foramina were obtained in 17 adults (9 edentulous women, mean age, 75 years; 4 edentulous men, mean age, 68 years; and 4 dentate men, mean age, 30 years). The mandibular outline was traced, digitized, and mathematically reconstructed with the elliptic Fourier series. Mandibular area, shape, and individual symmetry were quantified. RESULTS: Mandibular area and symmetry were larger in men than in women (P <.05). In men, no effect of edentulousness was observed in either area or symmetry. Mandibular shape seemed to be influenced neither by sex nor by the presence of teeth. CONCLUSION: Mandibular size and symmetry in the analyzed computed tomographic scan (which included only the mandibular basal bone) seemed to be sex related but independent of the dental status. Mandibular shape did not seem to be modified by sex or edentulousness. Different findings may be obtained in the analysis of a section of the alveolar bone.