Dental pulp vitality can be preserved after direct pulp capping with materials that can promote hard tissue
formation. The comparison of efficacy regarding dentin bridge formation of different direct pulp capping materials
is still limited. The objective of this study was to analyze and quantify the reparative dentin formation after direct
pulp capping with different direct pulp capping materials on mechanically injured dental pulp of rat molars through
micro-computerized tomographic analysis. Fifteen rat molars were mechanically exposed and assigned into three
groups according to the direct pulp capping materials used: no treatment (control), calcium hydroxide (Dycal®) and
Biodentine. After four weeks of treatment, the teeth were collected and processed for micro-computerized tomographic
imaging and histological evaluation. The ratio between total dentin volume and tissue volume was evaluated using
micro-computerized tomographic analysis software. Hematoxylin and eosin staining of the samples treated with
calcium hydroxide and Biodentine revealed the hard tissue formation resembled reparative dentin around the
exposure site where the capping materials were placed. Micro-computerized tomographic imaging identified the
location of reparative dentin formation after direct pulp capping. The average ratio of total dentin volume and tissue
volume was 0.6055±0.0641 in the control group, 0.7381±0.0535 in the Biodentine group and 0.7099±0.0361 in the
calcium hydroxide group. The calcium hydroxide and Biodentine® treated groups had a significantly higher total of
dentin volume and tissue volume ratio compared with the untreated control group (p=0.008). However, no statistical
significance was observed between the calcium hydroxide and the Biodentine® treated groups. Calcium hydroxide
and Biodentine® can promote reparative dentin formation when used as direct pulp capping materials. In addition,
micro-computerized tomographic imaging can be considered as a standard technique to quantify and localize the
location of reparative dentin formation.