The influence of hydraulic calcium silicate cements (HCSC) composition on the cell behaviour of human dental pulp stem cells (hDPSC)

Abstract

Introduction: There is growing interest in new endodontic materials used during vital pulp treatment (VPT), particularly hydraulic calcium silicate cements (HCSCs) including Biodentine™, TheraCal LC®, and TotalFill® formulations. Human dental pulp stem cells (hDPSCs) play a crucial role in reparative and regenerative pulp therapy through their capacity to differentiate into odontoblast-like cells and form reparative dentine. During VPT procedures, materials are designed to replace dentine and interact directly with viable pulp tissue. Understanding these material-tissue interactions is vital for predicting pulpal responses and optimising treatment outcomes.

Aim: To investigate the influence of different hydraulic calcium silicate cements on the behaviour of human dental pulp stem cells.

Methods: The study investigated the cellular response of hDPSCs to different HCSCs. The materials evaluated included Biodentine™, TheraCal LC®, TotalFill® BC RRM™ Fast Set Putty and TotalFill® BC RRM™ Putty. A multi-method approach was employed to assess cellular responses through metabolic activity, cell numbers and morphological analyses. Metabolic activity was assessed using the Resazurin assay under two experimental conditions: filtered extraction media and hanging insert methods. Cell numbers were quantified using the CyQUANT® assay, whilst morphological assessment was conducted using inverted microscopy. All analyses were performed at 24 and 48-hour time points. Additionally, scanning electron microscopy (SEM) was employed to evaluate cellular attachment to material surfaces.

Results: Biodentine™ demonstrated consistently superior performance across all evaluation parameters. Its ability to maintain high metabolic activity, support normal cell morphology and facilitate cellular attachment suggested it created an optimal microenvironment for hDPSC survival and function. This superior performance was particularly evident in both the extraction media and hanging insert experiments, where Biodentine™ exhibited the highest metabolic activity at both 24 and 48-hour time points. TotalFill® BC RRM™ Fast Set Putty emerged as a promising alternative, showing comparable performance to Biodentine™, particularly after 48 hours of exposure. The material demonstrated good biocompatibility, supporting normal cell morphology and cellular attachment, with metabolic activity levels approaching those of Biodentine™ after 48 hours. Conversely, TheraCal LC® consistently showed inferior biological performance across all assessment methods. The material exhibited significantly lower metabolic activity, altered cell morphology and notably poor cellular attachment. These findings raised concerns about its suitability for direct pulp capping procedures, particularly in cases where maintaining optimal stem cell function is crucial for successful pulp repair. The CyQUANT® assay revealed similar patterns, with Biodentine™ and the control group showing the highest cell numbers at 24 hours. SEM analysis confirmed robust cellular attachment on Biodentine™ and both TotalFill® formulations, whilst TheraCal LC® exhibited poor cellular attachment.

Conclusion/ Clinical application: Within the limitations of this in vitro study, Biodentine™ and TotalFill® BC RRM™ Fast Set Putty demonstrated superior biological performance, creating more favourable conditions for hDPSC survival and function compared with TheraCal LC®. The consistency of results across multiple assessment methods provided robust evidence for material-dependent effects on pulp cell behaviour, with important implications for material selection in VPT procedures. These findings have important clinical implications for material selection in VPT procedures. The superior biological performance of Biodentine™ and TotalFill® BC RRM™ Fast Set Putty suggests these materials may be more favourable choices for maintaining pulp cell viability and function. The consistent underperformance of TheraCal LC® indicates that careful consideration should be given to its use in direct pulp capping and pulpotomy procedures, particularly in cases where optimal stem cell function is crucial for successful pulp repair.