To evaluate the changes in Natural Head Position after Orthognathic surgeries in Class II patients and Class III patients

Abstract

After the introduction of cephalometric radiography, orthodontists have been using cephalometric analysis to plan orthodontic treatment and to evaluate the treatment results. For cephalometric analysis, Sella-Nasion plane and the Frankfort horizontal plane are considered as stable horizontal reference planes. Unfortunately, measurements based on the Frankfort horizontal plane do not always correspond with clinical examination. Therefore, the use of the true horizontal line (THL) and true vertical line (TVL) as alternatives seems to be advisable. This study was done in order to compare and evaluate the changes in natural head position in patients who underwent maxillary Lefort I osteotomy and mandibular set back orthognathic surgery. Thirteen pre treatment(T1) and post treatment(T2) lateral cephalometric radiographs were collected. The T1 lateral cephalometric radiographs were taken at the beginning of the treatment, and the T2 data immediately after the removal of the orthodontic appliances. The patients were instructed to stand in their natural position. 9 landmarks and 6 reference planes were traced. Results showed that Class I patients who had received conventional orthodontic treatment showed a minimal or no change in their NHP, but some Class III patients showed a change in their NHP,which tended towards head extension. Patients who have undergone Lefort I surgery and BSSO set back have shown the changes in their natural head position the differences were in their SNA, SNB, ANB, Facial contour angle and Frankfort horizontal plane angle.