Aim and objectiveTo assess the efficacy of the new Carisolv system and Polymer bur (SmartbursII®) for selective caries removal in primary molars clinically and microbiologically, compared with the conventional mechanical method.Materials and methodsSixty children with class I active carious lesions were selected. The children were randomly allocated to three groups (n = 20) according to the caries removal method. Under rubber dam isolation, dentin samples were taken before and after caries removal for microbial culture. Time spent in each technique was recorded. The clinical efficacy of caries removal was verified using caries detector dye. Patient satisfaction toward the treatment was evaluated using a facial image scale.ResultsThe median of caries detector dye scores was significantly lower in the conventional group compared to others (p value < 0.05). The mean time for caries removal was the longest with Carisolv (p value < 0.05). The median of facial image scale scores was significantly higher in the conventional group compared with others (p value < 0.05). The mean total viable bacterial count after caries removal was significantly higher in polymer bur group compared with others (p value < 0.05). While, there was no significant difference between Carisolv and conventional groups (p value > 0.05).ConclusionThe clinical efficacy of caries removal was highest with the mechanical method. Carisolv took the longest time for caries removal. Patient satisfaction was higher with Carisolv and polymer bur than the mechanical method. The antimicrobial efficacy of Carisolv and the mechanical method was higher than the polymer bur.Clinical significanceCarisolv is a viable alternative to the mechanical method in the management of dental caries, especially in children. Further studies are needed to assess the efficacy of caries removal by SmartbursII®.How to cite this articleAsal MA, Abdellatif AM, Hammouda HE. Clinical and Microbiological Assessment of Carisolv and Polymer Bur for Selective Caries Removal in Primary Molars. Int J Clin Pediatr Dent 2021;14(3):357–363.