Osteogenic Response of Saos-2 Cells to Calcium Silicate-based versus Hydroxyapatite-based Cements: A Comparative Study.

Abstract

Introduction: Bioceramic materials are integral to regenerative endodontics, yet comparative data on their osteogenic potential remain limited. This study compared the osteogenic potential of four bioceramics: hydroxyapatite (HA), a nano-hydroxyapatite/chitosan composite (n-HA/CSS), Angelus mineral trioxide aggregate (MTA), and calcium-enriched mixture (CEM) cement.

Materials and methods: Human osteoblast-like Saos-2 cells were exposed to materials via direct contact and extract models. Cell viability and proliferation were assessed using the MTT assay, attachment and morphology were examined by scanning electron microscopy (SEM), and osteogenic differentiation was evaluated by real-time PCR for alkaline phosphatase (ALP), bone sialoprotein (BSP), and osteocalcin (OC) at 3 and 6 days.

Results: All materials were non-cytotoxic. In direct culture, CEM significantly enhanced cell proliferation by day 3 (~3-fold, P<0.001). SEM revealed superior cell attachment and extracellular matrix secretion on n-HA/CS and CEM surfaces. Gene expression analysis demonstrated that CEM robustly upregulated ALP (~12-fold vs. control, P<0.001), a level 6-fold higher than MTA (P<0.05). Furthermore, both CEM and n-HA/CS promoted pronounced expression of the late markers BSP (~5-fold, P<0.001) and OC (10-fold and 12-fold, P<0.001 and P<0.001, respectively). MTA consistently elicited the lowest osteogenic response.

Conclusions: CEM and the n-HA/CS were identified as the strongest promoters of osteoblast proliferation and differentiation, indicating their superior bioactivity over MTA and HA and their potential for endodontic and surgical hard tissue regeneration.