RESUMEN
Abstract Objective: To evaluate in vitro erosive effect of analgesics on primary tooth enamel. Material and Methods: The pH and the titratable acidity measurements of the medicines were performed in triplicate using a digital pH meter. Enamel slabs of primary teeth flat and polished were selected by initial surface microhardness analysis. Medications were selected and specimens were assigned into five groups (n=12): Dalsy; Magnopyrol; Paracetamol; Tylenol; and distilled water (negative control). Specimens were immersed in 5 ml of each group solution for 30 min, 4x/day for three days and stored in artificial saliva at 37 °C between immersions and at night. Final microhardness was determined. The data were submitted to Oneway ANOVA and Tukey's test. Scanning electron microscopy (SEM) analysis was performed in three specimens of each group. Results: Medicines showed acidic pH and mean values of titratable acidity ranged from 1.46 to 11.66 ml of 0.1N NaOH. The mineral loss of Magnopyrol was statistically significant in relation to the control group (p<0.01). Magnopyrol showed higher values when compared to Tylenol (p<0.05). SEM images displayed microstructure alterations in the Paracetamol group. Conclusion: Despite the low pH values, only Magnopyrol showed greater enamel softening. Paracetamol demonstrated morphological changes in primary tooth enamel (AU).