Enamel Deproteinization before Acid Etching – A Scanning Electron Microscopic Observation

OBJECTIVES: This study was undertaken to evaluate the topographical features of enamel surface deproteinized with sodium hypochlorite (NaOCl) and etched with phosphoric acid (H3PO4) compared to phosphoric acid alone using Scanning Electron Microscopic (SEM) Analysis. STUDY DESIGN: 30 enamel blocks of 1 mm2 from ten human sound extracted permanent molars were obtained and treated as under: Group 1 (10 blocks): Enamel surface was etched with 37% H3PO4 gel for 15 seconds. Group 2 (10 blocks): Enamel surface was treated with 5.25% NaOCl for 60 seconds and then etched with 37% H3PO4 gel for 15 seconds. 10 enamel blocks were included in the control group where no treatment was carried out. The samples were subjected to SEM analysis and 5 microphotographs of each sample were obtained at 500X magnification and evaluated for the quality of etching pattern of the enamel in percentage (%) using Auto-CAD 2007 software. RESULTS: Mean values of etching pattern in Group 1 being 55.76% and Group 2 being 53.58%. No significant difference was observed between the two groups. CONCLUSION: The use of 37% phosphoric acid for 15 seconds still remains the best method for pretreatment of enamel.