Radiomorphometric indices of the mandible in a British female population

To examine the radiomorphometric indices of the mandible on panoramic radiographs in a population of British female patients, to identify their normal ranges and to investigate their relationships with age, detentition and social class.

Five indices, cortical width at the gonion (GI) and below the mental foramen (MI), the panoramic mandibular index (PMI), the mandibular cortical index (MCI) and one new index (measurement of cortical width at the antegonion; AI), were measured bilaterally on 500 panoramic radiographs of females by one trained observer. The measurements were analysed for ease of application, repeatability, relationships with age, dentition and social class and interrelationships between the variables.

All quantitative indices (GI, MI, PMI, AI), showed a significant, negative correlation with age. MCI showed an age-related distribution. Mandibular dentition exerted a significant influence on some indices, but social class had no influence. Intra-observer repeatability of MI, PMI and AI was fair (precision < 20%) but that for GI was poor. Intra-observer agreement in MCI assessments was excellent.

The age-related changes in mandibular radiomorphometric indices and their variation within each age band lend support to their potential use in identification of skeletal osteopenia. However, problems with repeatability and measurement precision identified in the pilot study, notably with GI, may be a considerable obstacle to their use in general practice.