Odontogenic differentiation and biomineralization potential of dental pulp stem cells inside Mg-based bioceramic scaffolds under low-level laser treatment

Abstract

This study aimed to investigate the potential of low-level laser irradiation (LLLI) to promote odontogenic differentiation and biomineralization by dental pulp stem cells (DPSCs) seeded inside bioceramic scaffolds. Mg-based, Zn-doped bioceramic scaffolds, synthesized by the sol-gel technique, were spotted with DPSCs and exposed to LLLI at 660 nm with maximum output power of 140 mw at fluencies (a) 2 and 4 J/cm to evaluate cell viability/proliferation by the MTT assay and (b) 4 J/cm to evaluate cell differentiation, using real-time PCR (expression of odontogenic markers) and a p-nitrophenylphosphate (pNPP)-based assay for alkaline phosphatase (ALP) activity measurement. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were used for structural/chemical characterization of the regenerated tissues. Exposure of the DPSCs/scaffold complexes to the proposed LLLI scheme was associated with statistically significant increase of odontogenesis-related markers (bone morphogenetic protein 2 (BMP-2): 22.4-fold, dentin sialophosphoprotein (DSPP): 28.4-fold, Osterix: 18.5-fold, and Runt-related transcription factor 2 (Runx2): 3.4-fold). ALP activity was significantly increased at 3 and 7 days inside the irradiated compared to that in the non-irradiated SC/DPSC complexes, but gradually decreased until 14 days. Newly formed Ca-P tissue was formed on the SC/DPSC complexes after 28 days of culture that attained the characteristics of bioapatite. Overall, LLLI treatment proved to be beneficial for odontogenic differentiation and biomineralization of DPSCs inside the bioceramic scaffolds, making this therapeutic modality promising for targeted dentin engineering.

Sol–gel bioglasses in dental and periodontal regeneration: A systematic review

“…Among the 52 papers, 11 have studied pure BGs, 23 have assessed doped‐glasses, and 18 have used composite materials …”

“…Studying the genes expressed by the cells placed in contact with glasses is essential to evaluate their ability to promote and to sustain cell differentiation, two steps necessary for tissue repair. Consequently, if it is possible to prove that sol–gel derived BGs are able, by dissolving their ions in the media, to sustain cell growth and proliferation, the only studies reporting a gene expression analysis allow to conclude on the actual effectiveness of BGs in triggering cells differentiation …”

“…It can also be observed that by doping the glass, it is possible to improve cell response and to tailor the material to provoke a specific effect. For example, Cu was added to trigger angiogenesis, Li, or Sr to activate the wnt /β‐catenin canonical pathway, Zn was proved to play an active role in sustaining and promoting dental pulp regeneration, Mg seems to ensure a real improvement of cells proliferation especially when it is incorporated in bioscaffolds, Zr has high corrosion resistance and a remarkable ability for being bonded directly to the bone (a property called osteointegration) and providing biocompatibility and antiallergenic properties, and magnetic Fe was used to improve several cellular aspects such as adhesion, proliferation and differentiation.…”

“…Four papers have assessed the effect of zinc (Zn) on DPSCs. These four studies have proved that Zn was not toxic for cells and supported cells growth/viability in a time‐dependent manner after 7–14 days of exposition.…”

Application of Stem Cells in Oral Disease Therapy: Progresses and Perspectives

“…Yadlapati et al showed that VEGF-loaded fiber was biocompatible and might be a promising scaffold for additional optimization and use in endodontic regenerative procedures (Yadlapati et al, 2017). Theocharidou et al proved low-level laser irradiation treatment to be beneficial for odontogenic differentiation and biomineralization of DPSCs inside the bioceramic scaffolds, making this therapeutic modality promising for targeted dentin engineering (Theocharidou et al, 2016). DPSCs and treated dentine matrix scaffolds were found to associate with significantly more bone formation when used to repair uninfected furcation perforations in the premolar teeth of dogs (Bakhtiar et al, 2016).…”