Inclusion Criteria:  Children who have two newly erupted non-carious mandibular permanent first molars that fissure sealant is indicated, Newly erupted first permanent molars show scores of 0 (Sound tooth surface)-1(First visual change in enamel) according to ICDAS II, Newly erupted first permanent molars show scores between 0-13 by using DIAGNOdent device, Children who haven't any systemic disease that prevents the application, Cooperative children who allowed the clinical applications.  Exclusion Criteria:  Teeth with proximal and initial caries, Teeth with applied fissure sealant, Teeth with developmental defects such as hypoplasia and restorations, Non-cooperative children who don't allow the clinical applications, Children and parents who denied the participation in the follow-up appointments.