Radiographic Evaluation of Frontal Sinus Dimensions and Anatomic Variations.

Aim: This study evaluated radiographic variations and measured dimensions of the non-pathologic frontal sinuses. Study Design: Retrospective. Place and Duration of Study: Orthodontics Department, Dental School, Shahid Beheshti University of Medical Sciences, 2003 to 2012. Methodology: Subjects older than 12 years with no sinus pathology were included. Borders of the frontal sinus were traced. Line drawings were scanned, and sinus dimensions were calculated by computer software by two examiners. In addition, asymmetry and shape of superior margin of sinus were evaluated. Gender differences were analyzed by independent sample t-test and chi square with a 0.05 level of significance. Results: A total of 66 subjects were included (40 female and 26 male). Height, width and area of the frontal sinus in the sagittal plane were 2.26 cm, 1.13 cm and 1.37 cm2, respectively. The corresponding numbers in the frontal plane were 2.79 cm, 5.00 cm and 7.04 cm2, respectively. Although all dimensions were larger in men than in women, it was not significant (P>0.05). Most of the cases had relatively symmetric frontal sinus. Conclusion: Size and shape of the frontal sinus varies among individuals. Frontal sinus is relatively larger in men than women.

Evaluation of craniofacial morphology in patients with obstructive sleep apnea using lateral cephalometry and dynamic MRI.

Context: Obstructive sleep apnea (OSA) is a potentially life-threatening disorder, characterized by repeated collapse of the upper airway during sleep with cessation of breathing. The altered mouth breathing produces morphological changes in craniofacial region. Aim: This study was designed to compare and validate the craniofacial morphological characteristics in patients with OSA using lateral cephalometry and to investigate the dentofacial characteristics of patients with OSA with respect to the obstructive sites determined by dynamic magnetic resonance imaging (MRI) to more accurately clarify the pathophysiological features. Materials and Methods: 10 patients with OSA were divided into two groups of five each according to their obstructive site determined by dynamic MRI. (1) Obstruction at the retropalatal and retroglossal region (Rp + Rg group) and (2) obstruction at the retropalatal region (Rp group). Lateral cephalogram both in upright and supine position was taken for all the subjects. In addition, dynamic MRI was performed to identify the sites of obstruction of the upper airway. Statistical analysis used: Independent t-test was performed to evaluate the significant difference in the upright cephalometric variables between the study and control group and between the two groups. The changes in skeletal and soft tissue parameters with change in posture was assessed within the study and control group by paired t test. P value of ≤0.05 was considered as statistically significant. Results: The study indicated that the first group of patients with both retropalatal and retroglossal obstruction showed signs of skeletal discrepancy that predisposed to obstruction at the retroglossal level and the soft tissue components like the soft palate and tongue that contributed to retropalatal obstruction. However, the second group of patients with only retropalatal obstruction had primarily soft tissue components associated with increased BMI that contributed to retropalatal obstruction. Conclusion: Evaluation of craniofacial morphology in OSA patients is bound to help the concerned specialist in recognizing the morphological changes induced by altered sleep pattern so as to provide the appropriate treatment.

Lateral cephalometric analysis in Thai patients without clinical features of obstructive sleep apnea syndrome.

Objective: To obtain referent normative values of lateral cephalometric parameters of the upper airway in Thai people without clinical features of obstructive sleep apnea syndrome (OSAS). Methods: A total of 105 healthy subjects (80 males and 25 females) were recruited. Inclusion criteria were healthy people age > 18 years with body mass index (BMI) of < 30 kg/m2, normal visual harmony of facial profile, no history of snoring or witnessed apnea, and no excessive daytime sleepiness (Epworth Sleepiness Scale ≤ 8). All subjects must have a regular sleep pattern with total sleep duration of 7-9 hours and must have no complaint of difficulty sleeping. Exclusion criteria were pregnant women, patients with previous orthodontic treatment, corrective jaw surgery, upper airway surgery, neoplasm, irradiation in head and neck, and patients who had underlying illnesses using medication or substance which affected the sleep-wake cycle. All subjects had lateral cephalometric radiographs taken with a standardized technique. Every data was measured twice on separate occasions. Results: The reliability of repeated measurements was excellent shown by intraclass correlation coefficients ranging from 0.95 to 0.99. The baseline data were presented in mean ± SD. SNA, SNB, PAS, MPH and PNS-P in males were 84.3 ± 4.0, 81.5 ± 4.1, 14.2 ± 3.4, 16.1 ± 5.3, and 34.8 ± 6.1, respectively. SNA, SNB, PAS, MPH and PNS-P in females were 84.4 ± 3.1, 80.7 ± 3.2, 11.1 ± 3.3, 10.8 ± 4.9, and 32.3 ± 3.1, respectively. The parameters that were different between both genders included N-ANS, GN-GO, H-PP, MPH, PAS, and TL. (p < 0.05) Conclusion: To date, this study has possibly represented the largest local database of lateral cephalometric measurements focusing on Thai people without clinical features of OSAS. It may be another useful reference for future research and clinical practice.