الفهرس 
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Abstract
A retrospective study done to examine the relationship between morphologic factors of mandibular protrusion patients and clinical indices of obstructive sleep apnea (OSA).
We recruited 52 patients (34 females and 18 males) in whom surgical-orthodontic treatment for mandibular prognathism was performed. Patients were divided into 2 groups: 1 jaw surgery group (30 patients) who underwent bilateral sagittal split ramus osteotomy, intraoral vertical ramus osteotomy, or intraoral vertical split ramus osteotomy and 2 jaw surgery group (22 patients) who underwent Le Fort I osteotomies combined with lower jaw operation. All of the subjects received standard pre- and postoperative orthodontic treatment. Morphologic changes were studied using cephalograms taken before surgery and 1 year after surgery. Functional changes studied using impulse oscillometry and pulse oximetry during sleep, both of which are clinically useful measures in assessing OSA, taken before surgery and 1 year after surgery.
Data analysis was performed utilizing SPSS software version 16.
The results were as follow:
1- Downward and backward position of the hyoid bone, decreased posterior airway space, increased the length of the tongue, increased tongue area, decreased airway area, and lower face cage area. With a significant difference in the postoperative period compared with preoperative status. These results were similar to obstructive sleep apnea syndrome (OSAS) patients’ morphologic characteristics. Thus, mandibular protrusion patients may have a risk for OSAS in the postoperative period.
2- Lower face cage area significantly decreased in 1 jaw group than 2 jaw group patients.
3- There was no evidence of OSAS in the postoperative period in patients of both groups.
4- No statistically significant difference between preoperative and postoperative results of central airway resistance (supine R20), and 3% ODI or between 1 jaw group and 2 Jaw group results.
5- A positive significant correlation was found between changes in 3% ODI (difference before and after surgery) and changes of tongue area and vertical position of hyoid bone in the 1 jaw surgery group.
6- Stepwise multiple regression analysis indicates that tongue area and airway area changes were statistically significant predictors of 3% ODI changes in the 1 jaw surgery group.
So in 2 jaw surgery, maxillary surgery compensates the effect of mandibular setback surgery on changes of postoperative morphologic factors. Mandibular setback surgery to mandibular protrusion patients was performed within the range of adequate movement distance, but precautions for risk of postoperative OSAS should be considered.
In 2 jaw surgery, maxillary surgery compensates the effect of mandibular setback surgery on changes of postoperative morphologic factors.
In 1 jaw surgery, 3% ODI changes were closely related to changes in tongue area, the vertical position of the hyoid bone and tongue area, airway area changes were its main determinants.
Mandibular setback surgery to mandibular protrusion patients was performed within the range of adequate movement distance, but precautions for the risk of postoperative OSAS should be considered.