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Calcium silicate cements (CSCs) are the choice materials for vital pulp therapy because of their bioactive properties, promotion of pulp repair, and dentin bridge formation. Despite the significant progress made in understanding CSCs' mechanisms of action, the key events that characterize the early interplay between CSC-dentin-pulp are still poorly understood. To address this gap, a microfluidic device, the "tooth-on-a-chip," which was developed to emulate the biomaterial-dentin-pulp interface, was used to test 1) the effect of CSCs (ProRoot, Biodentine, and TheraCal) on the viability and proliferation of human dental pulp stem cells, 2) variations of pH, and 3) release within the pulp chamber of transforming growth factor–β (TGFβ) as a surrogate of the bioactive dentin matrix molecules. ProRoot significantly increased the extraction of TGFβ (P < 0.05) within 24 to 72 h and, along with Biodentine, induced higher cell proliferation (P > 0.05), while TheraCal decreased cell viability and provoked atypical changes in cell morphology. No correlation between TGFβ levels and pH was observed. Further, we established a biofilm of Streptococcus mutans on-chip to model the biomaterial-biofilm-dentin interface and conducted a live and dead assay to test the antimicrobial capability of ProRoot in real time. In conclusion, the device allows for direct characterization of the interaction of bioactive dental materials with the dentin-pulp complex on a model of restored tooth while enabling assessment of antibiofilm properties at the interface in real time that was previously unattainable. [ABSTRACT FROM AUTHOR]

The use of protein cross-linking agents during bonding procedures has been recently proposed to improve bond durability. This study aimed to use zymography and in situ zymography techniques to evaluate the ability of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) cross-linker to inhibit matrix metalloproteinase (MMP) activity. The hypotheses tested were that: (1) bonding procedures increase dentin gelatinolytic activity and (2) EDC pre-treatment prevents this enzymatic activity. The zymographic assay was performed on protein extracts obtained from dentin powder treated with Optibond FL or Scotchbond 1XT with or without 0.3M EDC pre-treatment. For in situ zymography, adhesive/dentin interfaces were created with the same adhesives applied to acid-etched dentin slabs pre-treated or not with EDC conditioner. Zymograms revealed increased expression of dentin endogenous MMP-2 and -9 after adhesive application, while the use of EDC as a primer inactivated dentin gelatinases. Results of in situ zymograpy showed that hybrid layers of tested adhesives exhibited intense collagenolytic activity, while almost no fluorescence signal was detected when specimens were pre-treated with EDC. The correlative analysis used in this study demonstrated that EDC could contribute to inactivate endogenous dentin MMPs within the hybrid layer created by etch-and-rinse adhesives. [ABSTRACT FROM PUBLISHER]