Early Odontogenic Differentiation of Dental Pulp Stem Cells Treated with Nanohydroxyapatite-Silica-Glass Ionomer Cement.

Ismail Ab Rahman,Norhayati Luddin,Kannan Thirumulu Ponnuraj,Hii Siew Ching,Nik Rozainah Nik Abdul Ghani

doi:10.3390/polym12092125

Abstract

This study aimed to investigate the effects of nanohydroxyapatite–silica–glass ionomer cement (nanoHA–silica–GIC) on the differentiation of dental pulp stem cells (DPSCs) into odontogenic lineage. DPSCs were cultured in complete Minimum Essential Medium Eagle—Alpha Modification (α-MEM) with or without nanoHA–silica–GIC extract and conventional glass ionomer cement (cGIC) extract. Odontogenic differentiation of DPSCs was evaluated by real-time reverse transcription polymerase chain reaction (rRT–PCR) for odontogenic markers: dentin sialophosphoprotein (DSPP), dentin matrix protein 1 (DMP1), osteocalcin (OCN), osteopontin (OPN), alkaline phosphatase (ALP), collagen type I (COL1A1), and runt-related transcription factor 2 (RUNX2) on day 1, 7, 10, 14, and 21, which were normalized to the house keeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Untreated DPSCs were used as a control throughout the study. The expressions of DSPP and DMP1 were higher on days 7 and 10, that of OCN on day 10, those of OPN and ALP on day 14, and that of RUNX2 on day 1; COL1A1 exhibited a time-dependent increase from day 7 to day 14. Despite the above time-dependent variations, the expressions were comparable at a concentration of 6.25 mg/mL between the nanoHA–silica–GIC and cGIC groups. This offers empirical support that nanoHA–silica–GIC plays a role in the odontogenic differentiation of DPSCs.

Highlights

Dental pulp stem cells (DPSCs) were first isolated by Gronthos and his colleagues from human dental pulp [1]
The odontogenic markers selected for this study were dentin sialophosphoprotein (DSPP), dentin matrix protein 1 (DMP1), OCN, OPN, alkaline phosphatase (ALP), COL1A1, and RUNX2
HA particles exhibited enhanced mechanical properties in comparison with commercial glass ionomer cements (GICs) which could be due to the continuous formation of aluminium salt bridges, which provided the final strength of the cements [7]

Summary

Introduction

Dental pulp stem cells (DPSCs) were first isolated by Gronthos and his colleagues from human dental pulp [1]. GICs are widely used in dental application due to their many advantages such as biocompatibility, long-term release of fluoride which acts as an anticariogenic agent, elasticity similar to dentin, and ability to bond to the tooth structure directly [4,5]. Despite their advantages, they have certain limitations such as susceptibility to dehydration and poor physical and mechanical properties [6], which have limited the extensive use of GICs as a filling material in dentistry. In order to overcome the poor mechanical properties of GICs, a number of modifications of conventional GICs (cGICs) have been done such as incorporation of fiber-reinforcement, hydroxyapatite, and zirconia into

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