sajjad ashnagar students scientific research center, school of dentistry, tehran university of medical sciences, tehran, iran hessam nowzari research department, taipei academy of reconstructive dentistry, research expert, the italian ministry of education and research, los angeles, usa hanieh nokhbatolfoghahaei laser research center of dentistry, dental research institute, tehran university of medical sciences, tehran, iran behnoush yaghoub zadeh students scientific research center, school of dentistry, tehran university of medical sciences, tehran, iran nasim chiniforush laser research center of dentistry, dental research institute, tehran university of medical sciences, tehran, iran nastaran choukhachi zadeh school of dentistry, tehran university of medical sciences, tehran, iran