Shape of the lingula and its localization by panoramic radiograph versus dry mandibular measurement

To evaluate the incidence of lingula shapes in Thai adult mandibles and to compare the accuracy of panoramic radiograph measurement with the dry mandible measurements for localizing the position of the lingula.

Seventy-two dry adult mandibles (144 sides) from 52 males and 20 females of Thai origin were classified as triangular, truncated, nodular or assimilated. Twenty-three mandibles, composed of both first molar and canine on the same side (33 sides), were selected for distance measurement. The ten distances from the lingula to the anterior, posterior ramus, to the coronoid notch and lower border of the mandible were measured on the dry mandibles and compared with the same distances on panoramic radiographs. The distribution of the lingula shape is described. Paired t test and correlation were used to evaluate the accuracy of panoramic radiographs in localizing the position of the lingula.

Truncated lingula were most commonly found (68 sides or 47%). Nodular, triangular and assimilated shapes were found in 33 (23%), 24 (17%) and 19 subjects (13%), respectively. The distance differences between the panoramic radiograph measurement and the dry mandible measurement were statistically significant (P < 0.01). The positive correlations between the panoramic and dry skull measurements were high (0.59-0.91).

The lingula has different shapes in different populations. In adult Thai mandibles, the truncated lingula shape is most common. Panoramic radiographs present not only the position but also the shape and number of lingula and mandibular foramen. There is a high concordance between the measured distances in panoramic radiography and dry mandibles.