Xác định tỷ lệ mất răng sữa sớm ở học sinh 7- 11 tuổi tại trường tiểu học Nguyễn Trãi, Hà Đông, Hà Nội

Examine and interview 780 pupils of grade 15 (7-11 years old) Who has the first permanent molar and 4 madibular insicors errupting already in Nguyen Trai Primary School, Ha Dong, Ha Noi caused result: Rate of ELDM in pupils 7-11 years old is 7,82 percent; Rate of ELDM, base on age: highest in the age of 8. Lowest in the age of 11; Rate of ELDM: 50,8 percent in mandibular only; 29,5 percent in maxillary only 19,7 percent both in mandibular and maxilary; Rate of ELDM for E teeth higher than for D teeth; Pupils of group which have not ELDM almost have Angle I and Angle II. Reson of ELDM: causing by tooth decay is 88,5 percent.