Tongue is one of the important organs of our body. It plays the main role in many functions. Tongue posture also has a great significance on dentofacial deformities and the development of craniofacial structures. This study aimed to evaluate the relationship between tongue soft tissue and dentofacial deformities in Skeletal Class II (Retrognathism) and Skeletal Class III (Prognathism) groups. Cephalometric radiographs of 140 patients were randomly retrospective collected and allocated equally into 2 groups based on the ANB angle. Skeletal Class II or retrognathism was defined by ANB angle > 4°, and Skeletal Class III or prognathism was defined by ANB angle < 0°. The tongue soft tissue parameters of Skeletal Class II and Skeletal Class III were compared by the Mann-Whitney U test. The relationship between tongue soft tissue and skeletal cephalometric variables were assessed by Pearson’s correlation coefficient.

                The majority of the tongue variables mean (tongue length; TL, tongue height; TH, tongue-hyoid; THy) were significantly greater in Skeletal Class II than in Skeletal Class III (p < 0.01). The tongue tip position (TN) in Skeletal Class II was also higher but there was no significant difference. Although the values of tongue analysis in Skeletal Class II were more than in Skeletal Class III, the ratio of tongue length and tongue height (TL: TH) in both groups was approximately the same (Skeletal Class II 2.47±0.32, Skeletal Class III 2.46±0.3; p=0.904). Moreover, all tongue variables were correlated among themselves in both skeletal groups. There is a significant relationship between tongue soft tissue and dentofacial deformities. The cephalogram of tongue soft tissue revealed an exceptional degree of constancy in tongue length and tongue height ratio (TL: TH) in both skeletal groups.