*Sapaar Bayarmagnai1, Baatarkhuu Battulga1, Saruul Munkhbaatar1, Anun Andsaikhan1, Enkhjargal Tamir1, Lkhagvajargal Enkhsuren1, Oyunbaatar Bayarsaikhan1, Misheel Boldbaatar1, Purevjav Nyanrag1
(1. Department of Prosthodontics, School of Dentistry, Mongolian National University of Medical Sciences )