Tricalcium silicate cements: in-vitro comparative studies of mechanical and biological characteristics of relevance to regenerative endodontics

• Main Author: Ali, Mohamed Abdul Raouf Abdul Wahab
• Format: Dissertation
• Language: English

Tricalcium silicate cements (TSC), are bioactive ceramic materials with a wide range of clinical applications in the field of “regenerative endodontics”, i.e. tissue engineering concepts applied to regeneration of damaged or lost dental tissue. This broad definition includes both vital pulp therapy (VPT) and regenerative endodontic procedures (REP) in immature permanent teeth with necrotic pulps. Both procedures involve direct contact between stem cells and TSC: the ensuing interaction is an essential determinant of regeneration and/or repair. It is therefore important to determine the bioactivity and biocompatibility properties of TSC. In REP moreover, the application of TSC should take into account potential mechanical effects on teeth at greater risk of fracture because of the thin dentinal walls. In this thesis three commercially available TSC were compared: White MTA-Angelus (MTA), Biodentine and TotalFill BC Root Repair Material PUTTY (TotalFill). The surface microhardness of MTA, Biodentine and TotalFill was evaluated by the Vicker’s Hardness Test. Biodentine showed the highest microhardness whereas TotalFill, which failed to achieve a measurable level, had the lowest. Based on the Vicker’s test results, the potential effect of MTA, Biodentine and TotalFill on tooth resistance to fracture was investigated. The aim of Study 1 was to compare the fracture resistance of immature teeth treated with REP and MTA, Biodentine or TotalFill applied to the cervical area. The study utilized an acknowledged bovine tooth model. The teeth were prepared to simulate immature permanent teeth, then treated with REP and tested for fracture resistance. No differences in fracture resistance were observed in relation to the three TSC tested. Cellular responses to MTA, Biodentine and TotalFill were evaluated and compared in cell culture experiments. Cell proliferation was assessed by MTT assay and osteogenic/angiogenic/ inflammatory responses were assessed with qRT-PCR, ELISA, ALP quantification and Alizarin red staining. In Study 2 the effect of TSC on human bone marrow stem cells (hBMSC) was investigated. Compared to MTA and TotalFill, Biodentine had the least inhibitory effect on hBMSC proliferation. The osteogenic and angiogenic responses to the materials varied. Biodentine and TotalFill induced earlier changes at gene level. All TSC induced mineralization after 14 days, with MTA possibly demonstrating the greatest effect. In Study 3 the effect of TSC on human dental pul