Ethics approval and consent to participate
The researchers observed all the ethical codes including informed consent, confidentiality, plagiarism, double publication, data manipulation, and fake data generation. The study received approval ethical research code from ethics Committee of Shahid Beheshti University of Medical Sciences. And ethical research code for this study is IR.SBMU.PHNS.REC.1398.146.It should be noted that, verbal informed consent was obtained from students and their parents. The use of verbal informed consent was approved by the ethics Committee of Shahid Beheshti University of Medical Sciences.