Phytic acid derived bioactive calcium phosphosilicate (PSC) glasses with a high phosphate content were synthesised by using non-toxic phytic acid as a phosphorus precursor. This study aimed to verify the effects of PSC on the odontogenic differentiation and dentin–pulp complex-like tissue regeneration of dental pulp cells (DPCs). Nitrogen adsorption, field-emission scanning electron microscopy, Fourier transform infrared spectroscopy, pH measurement, and inductively coupled plasma optical emission spectroscopy analyses were performed to characterise PSC. Classical 45S5 bioactive glasses (45S5) were used as positive control. Cell proliferation (1, 3, 5, 7 and 9 days), odontogenic-related gene expression levels (3 and 7 days) and mineralisation ability (21 days) of human DPCs (hDPCs) were evaluated with methylthiazol tetrazolium assay, real-time polymerase chain reaction and alizarin red staining after hDPCs from third molars were treated with PSC or 45S5 extractions. Rat molar crowns with pulp tissues covered by PSC or 45S5 were transplanted subcutaneously into nude mice for 2 and 6 weeks to demonstrate their biological effects in vivo. Results revealed that the specific surface area of PSC was larger than that of 45S5. The PSC also induced hydroxycarbonate apatite precipitation earlier than 45S5. pH was slightly increased when the amount and dissolution time of PSCs were increased. By comparison, pH was remarkably increased by 45S5. The amounts of Si and P ions released by PSC (0.1 mg mL−1) were larger than those released by 45S5. Cell proliferation, mRNA expression levels of dentin sialophosphoprotein, dentin matrix protein 1 and osteocalcin and mineralisation of hDPCs were also more strongly promoted by PSC than by 45S5. In vivo, the amount of induced typical dentin-like tissues with odontoblast-like cells generated on the interface between materials and pulp tissues was higher in PSC than in 45S5. Only collagen-like tissues were observed in groups without bioactive glasses. These findings suggested that PSC enhanced the odontogenic differentiation of DPCs and dentin–pulp complex-like tissue regeneration. The PSC might be a potential candidate for vital pulp preservation and regeneration of the dentin–pulp complex.

The aims of this study were to compare the osteogenic effects of a novel nano-sized bioactive glass (BG) and a traditional micron-sized BG, and to verify whether mitogen-activated protein kinases (MAPKs) are involved and play a part in BG’s osteoblast gene activation. It was found that the effect of a nano-sized BG on MAPK phosphorylation is better than the traditional 45S5 BG. We prepared extractions of the novel nano-sized 58S BG and traditional 45S5 BG and compared their effect on osteoblast-like cells’ (MG-63 cell) proliferation, osteogenic gene and protein expressions, matrix mineralization and MAPK activation. We further investigated the signal transducing effect of the MAPK pathway on the BG’s osteogenic gene activation. Our results showed that nano-58S extraction enhanced the MG-63 cells’ proliferation and osteogenic gene expressions of alkaline phosphatase (ALP), collagen type I (Col I), Runt-related transcription factor 2 (Runx2) and osteocalcin (OCN). The results of ELISA showed more Col I and OCN protein production in the BG groups than in the control group. Greater mineralized nodule formation was found in the nano-58S BG group using alizarin red S staining. We also found that nano-58S and 45S5 BG activated MAPKs, specifically the ERK and p38 pathways, using western blotting. After blocking the ERK or p38 pathway, real-time PCR showed the osteogenic gene activation induced by the BG extractions was inhibited. Blocking the ERK pathway induced a more obvious inhibitory effect on the genes’ normal expression and activation. The significance of this study is that we found that the ERK and p38 MAPK pathways are involved and play an important part in BG’s osteogenic gene activation. The effect of the nano-sized BG on MAPK phosphorylation, osteogenic gene activation, and osteoblast differentiation and mineralization is better than the traditional 45S5 BG.

•Direct pulp capping on a rat first maxillary model was built.•Two kinds of bioactive glass (BG) pulp capping materials, namely BG-PB and BG-PB-SA were tested.•Histologic sections were made and stained; we evaluated the sections using a scoring system.•BG-PB and BG-PB-SA showed similar favorable responses with MTA on direct pulp capping.IntroductionThis study aimed to investigate dental pulp responses to novel bioactive glass (BG) pulp capping materials after direct pulp capping in vivo.MethodsNovel BG pulp capping materials are composed of powder and fluid. The powder is BG (82.36% SiO2, 15.36% CaO, and 2.28% P2O5), and the fluid is provided in 2 kinds: (1) phosphate buffer solution (BG-PB) and (2) phosphate buffer solution with the addition of 1 wt% sodium alginate (BG-PB-SA). After mixing the powder and fluid, BG-PB and BG-PB-SA were prepared. Cavities with mechanical pulp exposure were prepared on maxillary first molars of Wistar rats. The exposures were randomly capped with BG-PB, BG-PB-SA, or mineral trioxide aggregate (MTA). After 1 (n = 6) and 4 weeks (n = 8), maxillary segments were obtained and prepared for histologic analysis with a scoring system. Statistical analysis was performed using the Kruskal-Wallis and Mann-Whitney U tests with the significance set at .05.ResultsAfter 1 week, few inflammatory cells were present in the BG-PB, BG-PB-SA, and MTA groups. Moreover, a thin layer of newly generated matrix was observed in most specimens. After 4 weeks, all specimens from the 3 groups formed a heavy dentin bridge. BG-PB and BG-PB-SA groups exhibited no or slight inflammatory response, whereas the MTA group exhibited a slight to moderate inflammatory response. No significant difference was observed in pulp inflammation and dentin formation among the 3 groups at either time point (P > .05).ConclusionsWhen used as a pulp capping agent, BG-PB and BG-PB-SA had similar favorable cellular and inflammatory pulp responses to those of MTA. Therefore, BG is a promising pulp capping material.

The object of this study was to evaluate the effect of bioactive glass (BG) size on mineral formation on dentin surfaces. Totally demineralized dentin discs were treated using BG suspensions with different particle sizes: i.e., microscale bioactive glass (m-BG), submicroscale bioactive glass (sm-BG) and nanoscale bioactive glass (n-BG). Field-emission scanning electron microscopy and 3D profile measurement laser microscopy were used to observe the surface morphology and roughness. It was found that all BG particles could promoted mineral formation on dentin surfaces, while plug-like depositions were observed on the dentin discs treated by n-BG and they were more acid-resistant. The present results may imply that n-BG has potential clinical application for dentin hypersensitivity treatment.Bioactive glass could promote mineral formation on dentin surfaces, and plug-like depositions were observed on the dentin discs treated by nanoscale bioactive glass and they were more acid-resistant.

This study investigated the effects of novel submicron bioactive glass (sm-BG) particles on in vitro osteogenesis and compared them to those of microscale bioactive glass (m-BG) particles. The ability of sm-BG particles to generate precipitates on their surface in the presence of simulated body fluid (SBF) was examined, and the effect of sm-BG particles on in vitro osteogenesis was evaluated by culturing human osteoblast-like osteosarcoma (MG-63) cells on particle-coated plates. It was found that sm-BG induced formation of precipitates after incubation for 24 hours in SBF. Compared with m-BG, sm-BG particles better promoted MG-63 cell adhesion and they induced expression of the ALP, RUNX2 and COL1 genes at an earlier stage and to a greater degree. This study demonstrates that submicron bioactive glass particles possess a high capacity for precipitates formation in SBF and improved osteogenic properties when compared to microscale BG particles.

•We investigate the effects of the bioceramic iRoot BP Plus as a pulp capping agent in vitro and in vivo.•iRoot BP Plus enhanced the proliferation of hDPCs.•iRoot BP Plus exhibited good biocompatibility to pulp tissue and induced the formation of reparative dentin bridge.IntroductionThis study aims to investigate the effects of the bioceramic iRoot BP Plus (Innovative Bioceramix Inc, Vancouver, Canada) as a pulp capping agent in vitro and in vivo.MethodsIn vitro, human dental pulp cells (hDPCs) were seeded into plates with the prepared iRoot BP Plus or mineral trioxide aggregate (MTA) packed in the bottom of different wells. The proliferation of hDPCs was determined using the 3,(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. Meanwhile, 2 animal models of direct pulp capping and pulpotomy were applied in Wistar rats in vivo. The exposed pulps were capped with iRoot BP Plus or MTA. After 1 and 4 weeks, maxillary segments were obtained and prepared for histologic analysis.ResultshDPCs grew very well even in the place contacted with MTA or iRoot BP plus in vitro. MTA and iRoot BP Plus both enhanced the proliferation of hDPCs (P < .05). In vivo, results revealed that few inflammatory cells were present in the pulpal area corresponding to the pulp exposure. A slight layer of newly generated matrix was also observed next to MTA and iRoot BP Plus after 1 week. A complete reparative dentin bridge with polarizing odontoblastlike cells was detected in all specimens in the iRoot BP Plus group after 4 weeks.ConclusionsiRoot BP Plus exhibited good biocompatibility to pulp tissue and induced the proliferation of dental pulp cells and the formation of reparative dentin bridge. iRoot BP plus may be used as a pulp capping material for vital pulp therapy

•The potential of polycaprolactone/bioactive glass composite for tooth engineering application was primarily verified.•Material properties and odontogenic activity of polycaprolactone/submicron bioactive glass and traditional 45S5 bioactive glass scaffolds were compared.•The effects of novel monodispersed submicron bioactive glass in a hybrid scaffold on mineralization characteristics and odontogenic activity were evaluated.IntroductionThis study aimed to evaluate the potential applications of polycaprolactone (PCL)/submicron bioactive glass (smBG) hybrid composites for pulp and dentin tissue regeneration.MethodsPCL/smBG hybrid composites were made with novel monodispersive bioactive glass submicrospheres, and pure PCL and bioactive glass samples were used as controls. Surface characteristics were assessed by scanning electron microscopy. Crystalline apatite deposition in vitro was examined after incubation in simulated body fluid. Inductively coupled plasma spectroscopy was used to further analyze the concentration of Si ions released by the scaffolds. Cell adhesion and morphology of human dental pulp cells were observed by immunofluorescence staining. The proliferation and expression of odontogenic-related markers were subsequently investigated using the Cell Counting Kit-8 assay (Beyotime Institute of Biotechnology, Jiangsu, China), Western blotting, and real-time reverse-transcription polymerase chain reaction. Mineralization activity was assessed by alizarin red staining.ResultsCrystalline apatites were precipitated on the PCL/smBG hybrid and pure bioactive glass surfaces after incubation in vitro, and pure PCL did not exhibit precipitation. Surface deposition on PCL/smBG hybrids presented different topographies and was thicker than on pure bioactive glass scaffolds at a later stage. Human dental pulp cells had a significantly higher proliferation rate on the PCL/smBG hybrid than on the bioactive glass and PCL scaffolds. Furthermore, the integration of smBG into the hybrid scaffold significantly promoted the expression of markers for odontogenic differentiation. More mineralized nodules were generated in the PCL/smBG group than in the other 2 groups.ConclusionsPCL/smBG hybrid composites may serve as potential material for pulp repair and dentin regeneration. The physical and chemical properties of the bioactive glass component affect the bioactivity of hybrid composites.