A CBCT Study Of The Influences Of Tongue Volume And Position On Different Vertical Facial Patterns

Objective: The aim is to study the effect of tongue volume and position on the vertical facial patterns by cone beam computed tomography(CBCT),in order to provide evidence for the prevention,treatment of the orthodontics and the retention after the orthodontic treatment.Methods: 430 patients were collected,type II barium sulfate contrast agent was applied around the tongue,and the CBCT was taken.53 patients were selected according to the inclusion criteria,all of whom were patients with skeletal class I(0°?ANB?5°).According to the different vertical facial patterns,the 53 patients were divided into three groups: the high angle group(16 patients,average age: 23.73 ± 5.45 years),the normal angle group(20 patients,average age: 23.50±4.63 years),the low angle group(17 patients,average age: 22.35±3.96 years).The tongue volume was measured through mimics16.0 software.By establishing a three-dimensional coordinate system.The position of the tongue and the hyoid bone were measured through Invivo5 software.16 landmarks and 23 measurements were selected to evaluate the vertical indexes of the jaw from the CBCT image.The statistical analysis was performed with SPSS 21.0.Results:1.The tongue volume measurements of different vertical facial patterns.There were no significant difference in tongue volume(TV),oral cavity volume(OCC),TV/OCC among the three groups.2.The position of the tongue(TTx,TTy,TTz)of different vertical facial patterns.There were differences in the position of the tongue among the three groups.The position of the tongue in the high angle group was lower and posterior than that in the low angle group and the normal angle group(P<0.05).3.Correlation analysis between the tongue volume and the vertical indexes of the jaw.The TV was positively correlated with the mandibular plane angle(MP-FH)and negatively correlated with the overbite depth indicator(ODI)(P<0.05).4.Correlation analysis between tongue position and the vertical indexes of the jaw.The anteroposterior position of the tongue(TTy)was positively correlated with the mandibular plane angle(MP-SN and MP-FH)and the occlusal plane inclination(OP-SN).The vertical position of the tongue(TTz)was negatively correlated with MP-SN and MP-FH and positively correlated with the ratio(S-GO/N-Me)(P<0.05).5.Correlation analysis of hyoid bone positionThe anteroposterior position of the hyoid bone(Hy)was positively correlated with MP-FH(P<0.05),and positively correlated with the anteroposterior position of the tongue(TTy)(P<0.05).Conclusion: The tongue volume has little effect on the vertical facial patterns,while the position of the tongue has a great influence on it.With the position of the tongue was lower and posterior,the mandibular plane angle was to increase.