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Background & objectives: Ectopic eruption is a disorder in which the tooth does not follow its usual course and if not diagnosed in a timely manner, leads to occlusal problems. The aim of this study was to determine the frequency of ectopic eruption of the first permanent molar and canine in patients referred to Ardabil dental school.
Methods: By observing the panoramic radiographs, recorded from 2016 to 2017, the frequency of ectopic eruption of first permanent molars in children aged 5 to 8 years and permanent canine in children aged 10 to 13 years was determined. The frequency distribution based on sex, involved jaw, unilaterality and bilaterality were evaluated using Chi-Square test.
Results: the frequency of ectopic eruption of the first permanent molar and permanent canine was 2.1% and 6.4% respectively. There was no significant difference in the frequency of ectopic eruption of the first molar, based on the patient's gender (p=0.366), jaw (p=0.132), and unilateral or bilateral involvement (p=0.366).Also, there was no significant difference between the frequency of ectopic eruption of permanent canine and the patient's gender (p=0.384), unilateral or bilateral involvement (p=0.056). The ectopic eruption of the permanent canine in the maxilla was greater than the mandible (p=0.012).
Conclusions: In this study, the frequency values of ectopic eruption were 2.1% and 6.4% for the first permanent molar and permanent canine respectively that were in the range of other studies reported from other populations.
 

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Background & objectives: The purpose of this study was to determine the bacterial bioaerosols in indoor air of Ardabil universities and to investigate the factors affecting their concentration in Ardabil city.
Methods: Air sampling was performed using Andersen single-stage sampler at a flow rate of 28.3 liters per minute and a respiratory range of 10 min. In this study, trypticase soy agar containing cycloheximide antibiotic was used for bacterial culture. Biochemical tests such as DNase, catalase, oxidase, coagulase, bile esculin hydrolysis test, urease, citrate test, antibiotic resistance to novobiocin, bacitracin and optochin were used for identification and differentiation of isolates.
Result: The mean bacterial concentration in Ardabil university of medical sciences in the open air, outside the college, the halls, the classrooms and the staff rooms  was 18, 88.4, 76.6, 77.4 CFU/m³ , respectively. The concentration of bacteria in Islamic Azad university of Ardabil in the open air, outside the college, the halls, the classrooms and the staff rooms was 103, 97, 124, 132 CFU/m³, respectively. The dominant species of bacteria in indoor air were Staphylococcus aureus, Staphylococcus epidermidis, Actinomycetes and Bacillus, respectively.
Conclusion: According to the results of this study, it is found that the concentration of bacterial bioaerosols in indoor air is not more than standard, but the abundance of bacterial species can cause lung, intestinal and other diseases in academic personnel, staff and students in the long-term.