Tongue volume in adults with skeletal Class III dentofacial deformities

The size of the tongue is implicated as an essential etiological factor in the development of malocclusions. The aim of our study was to assess tongue size in skeletal Class III (SCIII) patients in comparison to adults with normal occlusion, using three-dimensional (3D) ultrasound.

The SCIII group consisted of 54 subjects; 34 females and 20 males and the control group contained 36 subjects, 18 from each gender with Class I relationship. 3D ultrasound images of the tongues were acquired, and then the tongues' volumes were assessed.

The males in both the SCIII and control groups had significantly larger tongue volumes than the female subjects (mean SCIII 100.8 ± 6.3 and control 92.4 ± 9.8 cm(3) in males vs. SCIII 77.4 ± 10.2 and control 67.2 ± 5.6 cm(3) in females). The highly significantly larger tongue volumes were in SCIII patients of both genders (p were less than 0.01 for female and 0.03 for male). The tongue volumes within the whole SCIII group were significantly larger with more negative Wits values.

The tongue volumes are significantly bigger in SCIII subjects than normal. Larger tongues correlate with more severe SCIII. The clinical importance of this data is that limited mandibular setback planning is necessary to prevent narrowing of respiratory airways.