Objective: To compare the effectiveness of polymer burs (SmartPrep, SS White) and conventional carbide burs in removing dentin caries. Method and Materials: Thirty extracted permanent teeth were assigned to 2 groups according to the caries removal technique. One experienced clinician performed all excavation procedures, monitoring the caries removal by checking the hardness of the dentin with a dental explorer. The excavation working time was documented and stopped in each group when a leather-hard texture was reached. After the teeth were embedded and sectioned (400 µm), the caries in the remaining dentin was assessed using a caries detector. On microscope images of the samples, the mean stain depth of the remaining carious tissue per tooth was measured by AnalySIS computer software. Results: Mean carious surface areas differed minimally but not statistically significantly after use of polymer burs (31.5 mm2 ± 0.18) and carbide burs (38.1 mm2 ± 0.15). Mean carious surface staining depth was slightly smaller with carbide burs (0.26 mm ± 1.38) than with polymer burs (0.40 mm ± 1.15). The mean-quartile test for the total carious surface (P = .363) and the carious margin (P = .681) showed no statistically significant differences. Of the carbide bur-treated samples, 84.5% were caries free as opposed to 93.0% in the polymer bur group. The results also showed no significant difference between the mean working time of the polymer burs (5.11 minutes) and the carbide burs (4.99 minutes). Conclusion: Under these experimental conditions, polymer burs and tungsten carbide burs were similarly effective for caries removal. Palabras clave: carbide bur, caries removal, dentin caries excavation, dentin hardness, polymer bur