This study aimed to evaluate carbonated hydroxyapatite (CHA)’s ability for mineral induction and its in vitro cytotoxicity with human dental pulp cells.

Precursors for the study include di-ammonium hydrogen phosphate and calcium nitrate tetrahydrate, with sodium hydrogen carbonate added to achieve different levels of carbonate substitution. The synthesized CHA samples are characterized using X-ray diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. Scanning electron microscopy (SEM) was used to observe morphology. For 14 days at 37°C, samples were submerged in simulated body fluid to assess their mineral induction capabilities. SEM was used to confirm apatite formation on sample surfaces. The cytotoxicity assay was used to assess the vitality of the cells following their exposure to various concentrations of CHA.

The Joint Committee on Powder Diffraction Standards data for HA aligned well with the results from X-ray diffraction analysis of CHA across 3 different concentrations, indicating strong agreement. Fourier transform infrared spectra indicated the presence of phosphate, hydroxyl, and carbonate groups within the samples. SEM and Energy-dispersive X-ray analysis show agglomerated and flaky nanoparticles. All the samples are bioactive, but the formation of apatite differs from one another. In vitro cytotoxicity assay showed that over 70% of cells maintain viability.

The results of this study may provide insight into the potential use of carbonated HA as a dental pulp-capping material for vital pulp therapy.

The aim of this study was to investigate the expression of 7 different sirtuin genes (SIRT1-SIRT7) in human dental pulp cells (HDPCs), and to determine the role of SIRTs in the odontoblastic differentiation potential of HDPCs.

HDPCs were isolated from freshly extracted third molar teeth of healthy patients and cultulred in odontoblastic differentiation inducing media. Osteocalcin (OCN) and dentin sialophosphoprotein (DSPP) expression was analyzed to evaluate the odontoblastic differentiation of HDPCs by reverse transcription-polymerase chain reaction (RT-PCR), while alizarin red staining was used for the mineralization assay. To investigate the expression of SIRTs during odontoblastic differentiation of HDPCs, real time PCR was also performed with RT-PCR.

During the culture of HDPCs in the differentiation inducing media, OCN, and DSPP mRNA expressions were increased. Mineralized nodule formation was also increased in the 14 days culture. All seven SIRT genes were expressed during the odontogenic induction period. SIRT4 expression was increased in a time-dependent manner.

Our study identified the expression of seven different SIRT genes in HDPCs, and revealed that SIRT4 could exert an influence on the odontoblast differentiation process. Further studies are needed to determine the effects of other SIRTs on the odontogenic potential of HDPCs.

We analyzed gene-expression profiles after 14 day odontogenic induction of human dental pulp cells (DPCs) using a DNA microarray and sought candidate genes possibly associated with mineralization.

Induced human dental pulp cells were obtained by culturing DPCs in odontogenic induction medium (OM) for 14 day. Cells exposed to normal culture medium were used as controls. Total RNA was extracted from cells and analyzed by microarray analysis and the key results were confirmed selectively by reverse-transcriptase polymerase chain reaction (RT-PCR). We also performed a gene set enrichment analysis (GSEA) of the microarray data.

Six hundred and five genes among the 47,320 probes on the BeadChip differed by a factor of more than two-fold in the induced cells. Of these, 217 genes were upregulated, and 388 were down-regulated. GSEA revealed that in the induced cells, genes implicated in Apoptosis and Signaling by wingless MMTV integration (Wnt) were significantly upregulated.

Genes implicated in Apoptosis and Signaling by Wnt are highly connected to the differentiation of dental pulp cells into odontoblast.