Smooth surface caries tRanslucent zone >50% present >Negative birefringence >Pore volume. 1% Department of Oral Pathology, Shandong University 10 http://1.51.214.13Department of Oral Pathology, Shandong University 10 http://1.51.214.13 Translucent zone 50% present Negative birefringence Pore volume: 1%