The Effect of Calcium hydroxide, Glass Ionomer and light cured resin modified calcium silicate on viability, proliferation and differentiation of stem cells from human exfoliated deciduous teeth

Abstract

Background: Vital pulp therapy, based on the use of stem cells, has promising research and therapeutic applications in dentistry. It is essential to understand the direct effect of capping materials on the dental pulp stem cells of primary teeth, which contribute to the healing powers of the tooth. The aim of this study is to evaluate the effect of different capping materials (Calcium Hydroxide (DyCal®) - Glass Ionomer (Fuji IX®) and light-cured resin modified calcium silicate (TheraCal LC®)) on the viability, proliferation, and differentiation of stem cells from human exfoliated deciduous teeth (SHEDs).

Methods: SHEDs were isolated from extracted primary teeth, then divided into four groups and each of the capping materials were applied to the stem cells as follows: group I the controls, group II with Ca(OH)2, group III with the GIC, and group IV with the Theracal LC. For all groups assessment of viability and proliferation rate was done using the MTT cell proliferation assay. Also, Differentiation was evaluated by measuring the gene expression of Alkaline phosphatase enzyme activity (ALP) and Dentin matrix protein-1 (DMP1) through quantitative real-time PCR. Morphological assessment was conducted using Alizarin Red S staining. All evaluations were performed after 7 and 14 days of culture.

Results: TheraCal LC showed the highest values of proliferation, which was significant only compared to the control group after 2 weeks (p = 0.012). After one week, TheraCal LC showed the highest significant values of ALP and DMP1 compared to all other groups (p < 0.001).

Conclusion: The three materials under study are biocompatible, maintain viability, and stimulate the proliferation and differentiation of SHEDs. However, TheraCal LC allows better proliferation of SHEDs than Dycal Ca(OH)2 and Fuji IX GIC.

Keywords: Calcium hydroxide; Differentiation; Glass ionomer cement; Primary teeth; Proliferation; SHEDs; TheraCal LC; Vital pulp therapy.

Fig. 1

Flow cytometry analysis of stem cell surface markers

Fig. 2

Bar chart showing the mean ALP for tested group. Different letters above bars indicates significant difference

Fig. 3

Bar chart showing the mean DMP1 for tested group. Different letters above bars indicates significant difference

Fig. 4

a Photomicrograph showing undifferentiated cells of the control group (day 7), b Photomicrograph showing undifferentiated cells of the control group (day 14)

Fig. 5

a Differentiated cells (day 7) subjected to Ca(OH)₂ stained with Alizarin Red showing calcific deposits on its cell borders.( 100 × magnification). b Differentiated cells (day 14) subjected to Ca(OH)₂ stained with Alizarin Red showing increase calcific deposits inside the cells and at the cell boundary. (100 × magnification)

Fig. 6

a Differentiated cells (day 7) subjected to Glass ionomer (group III) stained with Alizarin Red showing calcific deposits on its cell borders.(100 × magnification, b Differentiated cells (day 14) subjected to Glass ionomer stained with Alizarin Red showing increase calcific deposits inside the cells and at the cell boundary.( 100 × magnification)

Fig. 7

a Photomicrograph showing differentiated cells (day 7) subjected to resin modified calcium silicate (TheraCal LC) (group IV) stained with Alizarin Red showing calcific deposits on its cell borders. (100 × magnification), b (Day 14) showing increase calcific deposits inside the cells and at the cell boundary. ( 100 × magnification)