Objective: To assess the reparative hard tissue formed following direct pulp capping in carious permanent first molars using Biodentine (BD) and mineral trioxide aggregate (MTA) in 10- to 13-year-old children. Materials and methods: A total of 30 carious permanent mandibular first molars with vital pulp from 21 participants were included in the study. The teeth received BD or MTA as direct capping material over the exposed pulp tissue. By the end of the 8-week follow-up period, the outcome of the procedure was clinically assessed for signs of failure and for density, thickness and volume of the formed hard tissue using cone beam computed tomography (CBCT). Results: None of the teeth from both the BD and MTA groups showed signs of clinical failure by the end of the follow-up period. Reparative hard tissue formation was evident in all assessed CBCT images. The formed hard tissue in the BD group did not present higher statistically significant mean average thicknesses compared with the MTA group (P > 0.05); however, the density of hard tissue from the BD group was significantly higher (P 0.05) than that from the MTA group. Conclusions: Tricalcium silicate-based materials can be used with a high rate of success in direct pulp capping of teeth affected with caries in 10- to 13-year-olds. CBCT may represent an effective method for early detection of reparative hard tissue formation. Also, the hard tissue formed using BD showed higher density and thickness compared with MTA. Keywords: Biodentine, direct pulp capping, mineral trioxide aggregate (MTA)