Dentin caries beneath enamel cavity(tg ●Z= destructive zone ●P= Penetrative zone ●D= Demineralizative zone ●T= Translucent zone ●R= Reparative dentin Department of Oral Pathology, Shandong University http://1.51.214.13Department of Oral Pathology, Shandong University 9 http://1.51.214.13  Z=destructive zone  P= Penetrative zone  D=Demineralizative zone  T=Translucent zone  R=Reparative dentin