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Introduction: This study aims at examining the difference of pharyngeal airways in patients with different occlusion postures, hoping to improve diagnostic methods and provide a stable treatment plan for orthodontic patients. Materials and Methods:The data were gathered through CBCT radiographies of patients from a specialized center for radiology. In each occlusion group according to the performed pilot study, 30 people (90 people in 3 groups of class I, II and III, male and female each) were chosen as the sample. The two-dimentional cephalometric radiographs were obtained from 3D-radiographs, and the patients' malocclusion postures were determined according overjet and ANB angle, and finally grouped. Next, airway volume and dimensions were measured in cross sectional. Results: Statistical studies showed there is a significant relationship between anteroposterior positions of mandible and the volume of pharyngeal airway. Also, the volume of pharyngeal airway in class III patients is more than those of patients in class I. The volume of pharyngeal airway in class II patients is also less than those of class1 pa ents. Conclusion: Pharyngeal airway in class III is larger and in class II smaller. Therefore, considering this subject can lead to improving diagnostic ways, especially orthognatic surgery treatments, and providing a stable treatment plan for patients who need orthodentic treatment

Objective: To compare the success of self-drilling and self-tapping methods in the retraction of maxillary anterior teeth. Material and Methods: The study was conducted in 57 subjects with Cl II malocclusion who needed to be treated with extraction of four maxillary teeth. The selftapping method was used on the left side and the self-drilling method was used on the right side. Then, the pain rate of each method was recorded by the numerical rating scale (NRS). Statistical analysis was done by t-test and Chi-square test. The significance level in this study was considered at p-value<0.05. Results: Considering the clinical mobility as the failure, the success of treatment was equal in both methods and was 93%. The inflammation around the mini-screws was 8.8%. A significant relationship was found between the variables inflammation and success (p<0.05). The mean pain was 2.47, but there was no significant difference between the two methods in terms of pain score (p>0.05). There was a significant difference between the groups (p=0.03). The pain was significantly higher in the female. Conclusion: There is no difference between self-drilling and self-tapping methods in terms of success. Comparison of the pain between two genders, according to the replantation method, showed a significant difference in pain sensation between two genders. The pain sensation mean in female group was greater than male group.

Introduction: Formation of white spots and initial carious lesions are the most important complications of fixed orthodontic treatment. Preparation of orthodontic adhesives containing antimicrobial agents might be a practical solution for the prevention of the mentioned defects.&nbsp; Aim: The current study aims to assess the antimicrobial and cytotoxicity effects of a conventional orthodontic adhesive containing different concentrations of nano-graphene oxide (N-GO). Materials and methods: 50 Transbond XT orthodontic adhesive discs containing 0, 1, 2, 5, and 10% N-GO were prepared and sterilized by 25 kGy Gamma irradiation. After determination of cytotoxicity potential of modified orthodontic adhesive on human gingival fibroblast (HGF) cells, antimicrobial effects of the modified orthodontic adhesive against Streptococcus mutans in the preformed cariogenic biofilms was investigated using eluted components from composite discs by comparing the viable counts of bacteria after 3, 7, 15, 30, and 60 days of the aging process in artificial saliva. Results: Based on the results, there was no cytotoxic effects of modified orthodontic adhesive on HGF cells (p>0.05). Transbond XT orthodontic adhesive containing 5 and 10 wt% N-GO reduced considerably the mean total viable counts of S. mutans up to 30 days (p<0.05). However, at 60 days, only 10 wt% N-GO could statistically decrease the colony-forming unit (CFU)/mL of test microorganisms. Antimicrobial activity of eluted components from modified orthodontic adhesive discs against S. mutans was in line with the concentration of N-GO. Conclusions: At 5% and 10% concentrations, a modified orthodontic adhesive containing N-GO has a significant antimicrobial activity against S. mutans in cariogenic biofilms.&nbsp;