ABSTRACT
Purpose@#This study investigated the position of the hyoid bone and its relationship with airway dimensions in different skeletal malocclusion classes using cone-beam computed tomography (CBCT). @*Materials and Methods@#CBCT scans of 180 participants were categorized based on the A point-nasion-B point angle into class I, class Ⅱ, and class Ⅲ malocclusions. Eight linear and 2 angular hyoid parameters (H-C3, H-EB, H-PNS, H-Me, H-X, H-Y, H-[C3-Me], C3-Me, H-S-Ba, and H-N-S) were measured. A 3-dimensional airway model was designed to measure the minimum cross-sectional area, volume, and total and upper airway length. The mean cross-sectional area, morphology, and location of the airway were also evaluated. Data were analyzed using analysis of variance and the Pearson correlation test, with p values <0.05 indicating statistical significance. @*Results@#The mean airway volume differed significantly among the malocclusion classes (p<0.05). The smallest and largest volumes were noted in class Ⅱ (2107.8±844.7 mm3) and class Ⅲ (2826.6±2505.3 mm3), respectively. The means of most hyoid parameters (C3-Me, C3-H, H-Eb, H-Me, H-S-Ba, H-N-S, and H-PNS) differed significantly among the malocclusion classes. In all classes, H-Eb was correlated with the minimum cross-sectional area and airway morphology, and H-PNS was correlated with total airway length. A significant correlation was also noted between H-Y and total airway length in class Ⅱ and Ⅲ malocclusions and between H-Y and upper airway length in class I malocclusions. @*Conclusion@#The position of the hyoid bone was associated with airway dimensions and should be considered during orthognathic surgery due to the risk of airway obstruction.
ABSTRACT
Local bone augmentation in the posterior maxilla [sinus lift] before the placement of dental implants has become an acceptable treatment technique in implant dentistry. However, limited documented data are available on the results of this technique and relevant issues in Iran. The present study aimed at evaluating the surgical outcome of sinus lift and implant placement in warfare victims presenting to Ghazi Tabatabai Clinic during 2001-2008. In this retrospective study, 50 patients that had undergone sinus lift surgery were evaluated. All warfare victims presenting to the clinic who had a medical record and undergone sinus lift treatment were enrolled. Those with incomplete medical files were excluded from the study. The required data were extracted from patients' medical records and entered into a questionnaire. The mean duration of follow up was 53.32 +/- 23.05 months. The surgical success criterion was presence of osseointegrated implants in the oral cavity during the follow up period. Statistical analysis was performed using t-test and Fisher's exact test. Failed out of which 5 were in the sinus-lift area. Thus, the total success rate, the success rate of implants placed in the sinus lift area and the success rate of those out of the sinus lift area were 96.6%, 93.9% and 98%, respectively. The study results demonstrated high success rates for implants placed in sinus lift and non-sinus lift areas in warfare victims