Does maxillary advancement alter vocal acoustic parameters in class III skeletal patients?

Any change in the maxillary position can affect the length of the vocal tract. This cross-sectional study aimed to assess the vocal acoustic parameters in 24 class III skeletal patients who underwent Le Fort I osteotomy for maxillary advancement. The vocal acoustic parameters (fundamental frequency, and jitter and shimmer perturbation indexes) were studied before, and at three, seven, and 10 months after maxillary advancement. The age and gender of the patients were the variables of the study. The amount of maxillary advancement was the predictive factor, and the changes in vocal acoustic parameters the study outcomes. Repeated-measures ANOVA were used to analyse the vocal acoustic parameters at different time points. Mean (SD) maxillary advancement was 3.5 (0.59) mm (range 3 - 6 mm). Data analysis did not demonstrate any significant correlation between the mean amount of maxillary advancement and changes in vocal acoustic parameters except for frequency of the 'i' sound. The results did not show a substantial change in the vocal acoustic parameters at 10 months after orthognathic surgery compared with baseline. These changed at three and seven months, but had returned to their baseline preoperative state 10 months after surgery.

Does maxillary superior repositioning affect nasal airway function?

This study aimed to assess nasal airflow, nasal resistance, and the cross-sectional area of the nasal cavity in patients who have had maxillary superior repositioning (MSR). This is a cross-sectional study, and nasal airflow, nasal resistance, and the cross-sectional area of the nasal cavity were evaluated by rhinometry and acoustic rhinometry techniques in patients who had had MSR. Thirty-two patients were studied, and the mean (SD) MSR was 5.03 (1.61) (range 3-8) mm. There was a significant correlation between the mean MSR and the mean change in nasal airflow and nasal resistance (p=0.001 and p=0.005, respectively). There was also a correlation between MSR and the change in the cross-sectional area of the inferior concha (p=0.001), but there was no correlation between the mean MSR and the change in cross-sectional area of the isthmus (p=0.07). Nasal airflow increases when the mean MSR is less than 6.5mm, and when maxillary impaction is 6.5mm or more, nasal airflow decreases. It seems, therefore, that MSR of less than 6.5mm was associated with an improvement in nasal airflow. When maxillary impaction was more than 6.5mm, nasal airflow and the cross-sectional area of the nasal cavity decreased, and nasal resistance increased.

Evaluation of the Effect of Source Geometry on the Output of Miniature X-ray Tube for Electronic Brachytherapy through Simulation.

OBJECTIVE: The use of miniature X-ray source in electronic brachytherapy is on the rise so there is an urgent need to acquire more knowledge on X-ray spectrum production and distribution by a dose. The aim of this research was to investigate the influence of target thickness and geometry at the source of miniature X-ray tube on tube output. METHOD: Five sources were simulated based on problems each with a specific geometric structure and conditions using MCNPX code. Tallies proportional to the output were used to calculate the results for the influence of source geometry on output. RESULTS: The results of this work include the size of the optimal thickness of 5 miniature sources, energy spectrum of the sources per 50 kev and also the axial and transverse dose of simulated sources were calculated based on these thicknesses. The miniature source geometric was affected on the output x-ray tube. CONCLUSION: The result of this study demonstrates that hemispherical-conical, hemispherical and truncated-conical miniature sources were determined as the most suitable tools.

Otomycosis in central iran: a clinical and mycological study.

BACKGROUND: Otomycosis is a fungal infection of the external ear with bothersome symptoms. The aim of this study was to evaluate the prevalence of fungal agents, predisposing factors and characteristics of patients. METHODS: Between May 2008 and April 2010, 171 patients with clinical suspicion of otomycosis were enrolled and the samples from their external ear were examined for any mycological infection. RESULTS: Otomycosis was confirmed after mycological diagnosis in 69% of clinically suspected patients. The highest incidence of otomycosis was in autumn and in patients aged 21-40 years old. Working in dry dusty environment was a major predisposing factor. Pruritus was the most common symptom. Aspergillus flavus was the most common fungus in otomycosis followed by A. niger, Candida albicans, A. fumigatus, A. nidulans and C. parapsilosis. CONCLUSION: Clinical suspicion of otomycosis is important to prevent unnecessary use of antibiotics. Etiology of fungal pathogens in dry dusty regions is not similar to hot humid areas and this needs to be considered in future susceptibility tests and treatment of patients with otomycosis.