mojgan paknejad associtate professor, dental research center dentistry research institute, department of periodontics, school of dentistry, tehran university of medical sciences, tehran, iran ; dental implant research center, school of dentistry, tehran university of medical sciences, tehran, iran. amirreza rokn dental implant research center, school of dentistry, tehran university of medical sciences, tehran, iran ; professor, department of periodontoics, school of dentistry, tehran university of medical sciences, tehran, iran. nina rouzmeh assistant professor, department of periodontics, school of dentistry, qom university of medical sciences, qom, iran. mohadeseh heidari assistant professor, department of periodontics, school of dentistry, mazandaran university of medical sciences, mazandaran, iran. azadehzeinab titidej assistant professor, department of oral and maxillofacial pathology, school of dentistry, qazvin university of medical sciences, qazvin, iran. mohammad javad kharazifard statistical advisor, dental research center, tehran university of medical sciences, tehran, iran.