RESUMEN
AIM: To assess the efficiency of different polyacrylic acid concentrations on the removal of the smear layer after caries removal with hand and rotary instruments in affected dentine of primary teeth. STUDY DESIGN: In vitro study. METHODS: Six exfoliated primary molars with carious lesions were divided into two groups for caries removal: (1) hand instrument or (2) low speed bur. Each tooth was cut into four pieces. One piece assigned as control surface and the other three surfaces were actively treated with either 40% Fuji IXGP Liquid (GC America), or 40% Fuji IXGP Liquid diluted with water, and 25% Ketac Molar(TM) Conditioner (3M-ESPE). Surfaces were prepared for scanning electron microscopy (SEM). All images were submitted to an analysis by an experienced SEM professional, regarding presence or absence of smear layer and dentinal demineralization pattern. Chi-squared test was carried out (5% significance). RESULTS: There was no difference concerning the presence of a smear layer in relation to the method of caries removal, and 40% Fuji IXGP diluted with water causes a higher demineralization when compared with the control group of teeth (p=0.01). CONCLUSION: Treatments with polyacrylic acid are indicated prior to glass ionomer cement application in primary teeth.