Senthil Kumar, V (2015) Evaluation of changes in hyoid bone position and pharyngeal airway dimensions following mandibular setback surgery: A Cephalometric study. Masters thesis, Tamilnadu Government Dental College and Hospital, Chennai.
|
Text
240502015senthil_kumar.pdf Download (3MB) | Preview |
Abstract
AIM OF THE STUDY: The Aim of this study is to evaluate the changes in hyoid bone and pharyngeal airway dimensions in patients with prognathic mandible who had undergone mandibular setback surgery OBJECTIVES: 1. To evaluate the hyoid bone posit ion and pharyngeal airway dimensions in skeletal class III patients who had undergone mandibular setback surgery at pretreatment (T1), postsurgical (T2) and post treatment (T3) stages. 2. To evaluate the hyoid bone posit ion and pharyngeal airway dimension in normal skeletal class I patients. 3. To compare the changes in hyoid bone position and pharyngeal airway in the above two groups. MATERIALS AND METHODS: The samples for this study were chosen from the record archives of the Department of Orthodontics and Dentofacial Orthopaedics, Tamilnadu Government Dental College and Hospital, Chennai. Standardized lateral cephalograms of 20 patients diagnosed with Class III malocclusion due to prognathic mandible who underwent combined orthodontic and orthognathic surgical procedures between years 2009 and 2012 were analyzed. All these patients underwent presurgical orthodontics followed by mandibular setback surgery through Bilateral Sagittal Split ramus Osteotomy (BSSO) to correct mandibular prognathism and post surgical orthodontics for final settling of occlusion. Standardized lateral cephalograms of 20 patients diagnosed with class I malocclusion were taken as control group and analyzed. A good visibility of hyoid bone was ensured in all these lateral cephalograms. The age range was between 18 and 25 years. Inclusion and exclusion criteria were analyzed from clinical records of these patients. SUMMARY AND CONCLUSION: Pharyngeal airway dimension plays an important role in dentofacial development. Although mandibular setback surgeries like Bilateral Sagittal Split ramus Osteotomy (BSSO) could improve the occlusion, function and esthetics by changing the position of prognathic mandible in patients, it is likely to cause narrowing of pharyngeal airway space and changes in hyoid bone posit ion5. Narrowing of pharyngeal airway through setback surgery may contribute to treatment relapse apart from inducing the development of Obstructive Sleep Apnoea Syndrome (OSAS) 80. Hence it is essential to estimate and understand the changes in airway dimension s and hyoid bone positions following the mandibular set back surgeries. This study was therefore performed to evaluate the changes if any in hyoid bone position and pharyngeal airway dimensions following mandibular setback surgery in patients with prognathic mandible, at immediate post -operative stage and at the end of the whole orthodontic treatment. Following conclusions were derived from this study: 1. Skeletal Class III patients with prognathic mandible exhibited significantly larger pharyngeal airway space than the skeletal Class I individuals at pretreatment stage. 2. Significant narrowing of pharyngeal airway space occurred in Skeletal Class III patients with prognathic mandible immediately after surgery. 3. The post treatment pharyngeal airway parameters of the Skeletal Class III patients with prognathic mandible corresponded to the pretreatment parameters of skeletal Class I individuals. 4. Al though some surgical relapse following BSSO occurred in the said Skeletal Class III patients at post treatment stage, the pharyngeal airway parameters which were narrowed immediately after surgery, did not subsequently increase and was still maintained in the same narrowed dimension as found at postsurgical time. 5. The hyoid bone moved inferiorly and posteriorly immediately after surgery probably due to the attached soft tissue structures. 6. However the hyoid bone returned to its presurgical posit ion at the time of treatment completion.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | hyoid bone position ; pharyngeal airway dimensions ; mandibular setback surgery ; Cephalometric study. |
| Subjects: | DENTAL > Orthodontics and Dentofacial Orthopedics |
| Depositing User: | Subramani R |
| Date Deposited: | 14 Oct 2018 19:19 |
| Last Modified: | 14 Oct 2018 19:19 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/9890 |
Actions (login required)
 |
View Item |
