Cephalometric appraisal of tongue and related soft tissues in normal and open bite subjects at rest.

Aim: To compare the tongue position of normal and open bite subjects at rest and to study if there is any difference in the hyoid bone and posterior pharyngeal wall positions in normal and open bite subjects.

Materials And Methods: Sample size consisted of 48 individuals with 24 subjects having normal occlusion and 24 subjects having open bite malocclusion within the age range of 16 to 25 y. Standardized Lateral cephalograms were taken for all the subjects. The subjects were asked to protrude their tongue as much as possible. The dorsum of the tongue was then coated with a palatable suspension of Barium Sulphate (MICROBAR). The subjects were asked to swallow on command, after 10 sec of the swallow, lateral cephalograms were taken.

Statistical Analysis: t-test

Results: The antero-posterior relationship of maxilla and mandible to the cranial base is normal in both the groups. The open bite subjects had a larger over jet and as compared to the normal subjects, and had steeper mandibular planes.It was also seen that as the total tongue occupancy area increased so did the partial tongue occupancy area.

Conclusion: A significant positive correlation was found between the horizontal position of the tongue tip and the lower incisor position in the normal group, also for the ratio of total tongue area to total oral area & the ratio of upper tongue area to the anterior oral area in the normal and openbite groups. There was no difference in the position of the tongue, hyoid bone and posterior wall in the normal and openbite groups. The mandibular plane angle and palatal plane - mandibular plane angles were found to be larger in the openbite subjects as compared to normal subjects. Supra-eruption of the maxillary molars was seen in the openbite group leading to a downward and backward rotation of the mandible. The maxillary and mandibular incisors were more proclinated in the normal as well as openbite groups.