Comparative cephalometric evaluation of changes in tongue and hyoid bone position in class i bimaxillary dentoalveolar protrusion after orthodontic treatment

Background and objective: Facial esthetics is one of the major concerns of most patients seeking orthodontic treatment. Bimaxillary proclination can be characterized as a condition where the upper and lower incisors are proclined and protrusive which results in increased lip procumbancy. The aim of the study is to determine the effect of anterior teeth retraction on hyoid bone position, tongue position and posture in Angle’s Class I bimaxillary dentoalveolar protrusion cases with first premolar extraction. Materials and methods: Pre and post treatment lateral cephalogram of twenty Class I bimaxillary dentoalveolar protrusion patients in the age group of 15-25years treated orthodontically as maximum anchorage cases with Pre-adjusted Edgewise Appliances (MBT prescription) with extraction of all first premolars were compared. Conclusion: extraction of four first premolars for retraction of anteriors in bimaxillary dentoalveolar protrusion cases showed significant posteroinferior displacement of hyoid bone. There was a reduction in the total tongue space, tongue length and air way.