To assess clinically and radiographically the success of pulp capping procedure done in traumatically exposed permanent posterior teeth using a novel injectable treated dentin matrix hydrogel (TDMH), Biodentine, and MTA and to evaluate the formed dentin bridge under the capping materials using CBCT imaging.45 patients subjected to accidental traumatic pulp exposures by undergraduate dental students are allocated for this study. For each patient, a pulp capping procedure was done. TDMH was formed of TDM powder and sodium alginate to be injected and then hardened in the defect area. Patients were assigned to 3 groups: TDMH, Biodentine, and MTA, respectively, and returned to the clinic after 3, 6, 12, 18, and 24 months for clinical and radiographic examinations. Tomographic data, including thickness and density of formed dentin bridges, were evaluated at the end of the study period compared to the base line. Pulp sensitivity was evaluated throughout the study period using thermal testing and electric pulp tester.During the follow-up period, all patients were asymptomatic with no clinical signs and symptoms and revealed no radiographic signs of pathosis. However, tomographic evaluation showed the tested materials to have different levels of impact on formed dentin bridges with TDMH group resulted in significantly superior dentin bridges of a higher radiodensity and thickness than Biodentine and MTA.TDMH has a greater potential to induce dentin bridge formation than Biodentine and MTA under standardized conditions. Additionally, CBCT imaging was confirmed as a non-invasive and inclusive approach to evaluate the formed dentin bridges after pulp capping procedure.Direct pulp capping can be done successfully with this novel injectable pulp capping material in future clinical applications.PACTR201901866476410.