UCLA

The development of pulp capping agents has been instrumental in promoting reparative dentin formation and facilitating pulpal repair in response to pulp exposure during extensive caries excavation. Although calcium hydroxide has been used as the gold standard for pulp capping since decades, the development of mineral trioxide aggregate (MTA) and its derivatives, also known as hydraulic calcium-silicate cements (HCSCs) have ushered in a new wave of therapeutic pulp capping agents. Nonetheless, there is limited evidence about the pulpal toxicity and dentin regenerative capacity of these materials. In the current study, the effects of 4 of these HCSCs (PROROOT� MTA, TheraCal LC, EndoSequence BC RRM, Endo-Eze™ MTAFlow) along with the control groups, composite and UltraCal� XS (Dycal)on reparative dentin and dentinal bridge formation and periapical bone loss were evaluated radiographically and histologically in mice. Pulp exposure was induced bilaterally in maxillary first molars of C57/BL6 mice. The maxillae were harvested, fixed, and subjected to μCT scanning, three-dimensional volumetric analysis and Hematoxylin and Eosin staining (H &E) was done to evaluate the reparative potential of the pulp capping materials. Tartrate-Resistant Acid Phosphotase (TRAP) staining was performed, and osteoclasts were quantified. Among the five HCSCs used for pulp capping, only UltraCal� XS (Dycal) failed to induce reparative dentin and dentinal bridge formation, instead inducing periapical bone loss. Although TheraCal LC also induced periapical bone loss, significantly more teeth treated with UltraCal � XS (Dycal) developed periapical radiolucency’s. Histologically, dentinal bridge formation was observed in all HCSCs except UltraCal� XS (Dycal). Histologically, TRAP+ osteoclasts were absent in all the HCSCs. Although some samples of Theracal LC showed a few TRAP+ osteoclasts, significantly more were seen in the UltraCal � XS (Dycal) group. These findings indicate that with the exception of UltraCal� XS (Dycal), all HCSC derivative materials evaluated are comparatively effective to the original PROROOT� MTA in promoting reparative dentin formation and pulpal repair.