RESUMO
UNLABELLED: Aim of study is to compare the effect of etching with ortho-phosphoric acid on sound dentine, affected dentine and sclerotic dentine through AFM analysis. MATERIAL AND METHODS: The group study included 30 extracted third molars, 20 with acute and chronic carious lesions and 10 intact teeth. Teeth were sectioned in long axe to prepare sections with carious lesions surrounded by sound dentine. The sound teeth were sectioned to a depth of dentine comparable with carious lesions depth. The sections were etched with 37% ortho-phosphoric acid. The surface roughness was determined initially and after etching using AFM analysis. The results were expressed as relative variation of squared roughness. RESULTS: The values of relative roughness indices were between 2.78 and 3 for sclerotic dentine, 3.18 and 3.26 for sound dentine, 3.32 and 3.38 for affected dentine. The highest values of roughness index were recorded for the affected dentine samples. Significant statistically values were recorded when comparing relative roughness indices for sclerotic dentine with relative roughness indices for affected dentine and sound dentine. CONCLUSIONS: clerotic dentine has significant higher resistance to the action of ortho-phosphoric acid than affected dentine and sound dentine. The lowest resistance to the action of etching agent was recorded for the affected dentine.
