2. Epidemiology ● Memery(1870): o The Neolithic Age 2.94% o The bronze Age 21.879% o The Iron Age 40.67% Department Of Oral Pathology, Shandong University 2htp://1.51.214.13Department Of Oral Pathology, Shandong University 2 http://1.51.214.13  Mumery(1870): o The Neolithic Age 2.94% o The Bronze Age 21.87% o The Iron Age 40.67%