A Biphasic Calcium Phosphate Cement Enhances Dentin Regeneration by Dental Pulp Stem Cells and Promotes Macrophages M2 Phenotype In Vitro

Effects of inorganic phosphate on stem cells isolated from human exfoliated deciduous teeth

Calcium phosphate-based materials (CaP) are introduced as potential dental pulp capping materials for deciduous teeth. The present study investigated the influence of inorganic phosphate (Pi) on regulating stem cells isolated from human exfoliated deciduous teeth (SHED). SHEDs were treated with Pi. Cell cycle progression and apoptosis were examined using flow cytometry analysis. Osteo/odontogenic and adipogenic differentiation were analyzed using alizarin red S and oil red O staining, respectively. The mRNA expression profile was investigated using a high-throughput RNA sequencing technique. Pi increased the late apoptotic cell population while cell cycle progression was not altered. Pi upregulated osteo/odontoblastic gene expression and enhanced calcium deposition. Pi-induced mineralization was reversed by pretreatment of cells with Foscarnet, or p38 inhibitor. Pi treatment inhibited adipogenic differentiation as determined by decreased PPARγ expression and reduced intracellular lipid accumulation. Bioinformatic analysis of gene expression profiles demonstrated several involved pathways, including PI3K/AKT, MAPK, EGFR, and VEGF signaling. In conclusion, Pi enhanced osteo/odontogenic but inhibited adipogenic differentiation in SHED.

Immunomodulatory Antibacterial Hydrogel for Wound Infection Management

Background

Wound healing has always been a focal point in clinical work. Bacterial infections and immune microenvironment disorders can both hinder normal wound healing. Current wound dressings only serve a covering function. Developing wound dressings with antibacterial and immunomodulatory functions is crucial for aiding wound healing. To address this issue, we have developed a hydrogel with antibacterial and immunomodulatory functions for managing infected wounds.

Methods

The present study describes a photo-crosslinked antibacterial hydrogel composed of curcumin, silver nanoparticles-loaded reduced graphene oxide, and silk fibroin methacryloyl for the treatment of infected wounds. The study assessed its antibacterial properties and its capacity to induce macrophage M2 polarization through in vitro and in vivo experiments.

Results

The hydrogel demonstrates robust antibacterial properties and enhances macrophage M2 polarization in both in vitro and in vivo settings. Moreover, it accelerates the healing of infected wounds in vivo by stimulating collagen deposition and angiogenesis.

Conclusion

Overall, this hydrogel shows great potential in managing wound infections.

Bioactive ceramic-based materials: beneficial properties and potential applications in dental repair and regeneration

Bioactive ceramics, primarily consisting of bioactive glasses, glass-ceramics, calcium orthophosphate ceramics, calcium silicate ceramics and calcium carbonate ceramics, have received great attention in the past decades given their biocompatible nature and excellent bioactivity in stimulating cell proliferation, differentiation and tissue regeneration. Recent studies have tried to combine bioactive ceramics with bioactive ions, polymers, bioactive proteins and other chemicals to improve their mechanical and biological properties, thus rendering them more valid in tissue engineering scaffolds. This review presents the beneficial properties and potential applications of bioactive ceramic-based materials in dentistry, particularly in the repair and regeneration of dental hard tissue, pulp-dentin complex, periodontal tissue and bone tissue. Moreover, greater insights into the mechanisms of bioactive ceramics and the development of ceramic-based materials are provided.

The Potential Uses of Baobab Tree's Medicinal Effects in Dentistry: A Literature Review

Adansonia digitata (Baobab) tree is an African tree with a long history in traditional medicine. The local inhabitants of Africa have been using the different tree components to treat medical diseases, such as fever, diarrhea, malaria, cough, dysentery, and microbial infections. Recently, the tree gained the attention of scientists due to its medical and pharmaceutical properties and nutritional values, which generated a myriad number of investigations regarding its phytochemical and macro- and micronutrient contents. The fruit pulp is especially rich in vitamin C, pectin, fibers, and minerals such as calcium, magnesium, potassium, phosphorus, zinc, iron, and copper. Additionally, the leaves contain high levels of calcium, while the seeds are considered a good source of protein and fat. Altogether, they contain a variety of polyphenols, fatty acids, and amino acids. The tree extracts possess potent antioxidant, cell-protective, and anti-inflammatory activities. However, no information was found in the literature about the use of Baobab tree products in the dental field. The aim of this review is to discuss the well-documented medical effects and chemical and mineral components of the different Baobab tree parts from a dental point of view to open more areas of research concerning its potential applications in the dental field. Antioxidants and vitamin C are known to help in maintaining healthy periodontal and gingival tissues. They also help in wound healing and alveolar bone integrity. Moreover, phytochemicals and phenolic compounds have been utilized in controlling dental plaque and manufacturing intracanal medications as they manifest antimicrobial and anti-inflammatory activities. Furthermore, calcium and phosphorus incorporation in dental biomaterials is commonly used in vital pulp therapy and repairing bone defects. After reviewing the reported medicinal and pharmaceutical activities of the Baobab tree, it can be inferred that the tree extracts possess potential uses in the dental field, which requires further investigation for validation.

Property and biological effects of the cuttlebone derived calcium phosphate particles, a potential bioactive bone substitute material

Cuttlebone (CB) is a marine waste-derived biomaterial and a rich source of calcium carbonate for the biosynthesis of the calcium phosphate (CaP) particles. The current study aimed to synthesize CB derived biphasic calcium phosphate (CB-BCP) and investigate biological activity of the CB-CaP: hydroxyapatite (CB-HA), beta-tricalcium phosphate (CB-b-TCP) and biphasic 60:40 (w/w) HA/b-TCP (CB-BCP) with the human dental pulp stem cells (hDPSCs). The particles were synthesized using solid state reactions under mild condition and properties of the particles were compared with a commercial BCP as a reference material. Morphology, particle size, physicochemical properties, mineral contents, and the ion released patterns of the particles were examined. Then the particle/cell interaction, cell cytotoxicity and osteogenic property of the particles were investigated in the direct and indirect cell culture models. It was found that an average particles size of the CB-HA was 304.73 ± 4.19 nm, CB-b-TCP, 503.17 ± 23.06 nm and CB-BCP, 1394.67 ± 168.19 nm. The physicochemical characteristics of the CB-CaP were consistent with the HA, b-TCP and BCP. The highest level of calcium (Ca) was found in the mineral contents and the preincubated medium of the CB-BCP and traces of fluoride, magnesium, strontium, and zinc were identified in the CB-CaP. The cell cytotoxicity and osteogenic property of the particles were dose dependent. The particles adhered on cell surface and were internalized into the cell cytoplasm. The CB-BCP and CB-HA indirectly and directly promote osteoblastic differentiations of the hDPSCs in stronger levels than other groups. The CB-BCP and CB-HA were potential bioactive bone substitute materials.

Calcium Phosphate Delivery Systems for Regeneration and Biomineralization of Mineralized Tissues of the Craniofacial Complex

Calcium phosphate (CaP)-based materials have been extensively used for mineralized tissues in the craniofacial complex. Owing to their excellent biocompatibility, biodegradability, and inherent osteoconductive nature, their use as delivery systems for drugs and bioactive factors has several advantages. Of the three mineralized tissues in the craniofacial complex (bone, dentin, and enamel), only bone and dentin have some regenerative properties that can diminish due to disease and severe injuries. Therefore, targeting these regenerative tissues with CaP delivery systems carrying relevant drugs, morphogenic factors, and ions is imperative to improve tissue health in the mineralized tissue engineering field. In this review, the use of CaP-based microparticles, nanoparticles, and polymer-induced liquid precursor (PILPs) amorphous CaP nanodroplets for delivery to craniofacial bone and dentin are discussed. The use of these various form factors to obtain either a high local concentration of cargo at the macroscale and/or to deliver cargos precisely to nanoscale structures is also described. Finally, perspectives on the field using these CaP materials and next steps for the future delivery to the craniofacial complex are presented.

A Molecular View on Biomaterials and Dental Stem Cells Interactions: Literature Review

Biomaterials and stem cells are essential components in the field of regenerative medicine. Various biomaterials have been designed that have appropriate biochemical and biophysical characteristics to mimic the microenvironment of an extracellular matrix. Dental stem cells (DT-MSCs) represent a novel source for the development of autologous therapies due to their easy availability. Although research on biomaterials and DT-MSCs has progressed, there are still challenges in the characteristics of biomaterials and the molecular mechanisms involved in regulating the behavior of DT-MSCs. In this review, the characteristics of biomaterials are summarized, and their classification according to their source, bioactivity, and different biological effects on the expansion and differentiation of DT-MSCs is summarized. Finally, advances in research on the interaction of biomaterials and the molecular components involved (mechanosensors and mechanotransduction) in DT-MSCs during their proliferation and differentiation are analyzed. Understanding the molecular dynamics of DT-MSCs and biomaterials can contribute to research in regenerative medicine and the development of autologous stem cell therapies.

Calcium Phosphate Cement Promotes Odontoblastic Differentiation of Dental Pulp Cells In Vitro and In Vivo

In the case of pulp injury, odontoblastic differentiation of dental pulp cells (DPCs) at the site of the exposed pulp is necessary for a successful direct pulp capping treatment. Calcium phosphate cement (CPC), a kind of hydroxyapatite-like bone cement, exhibits therapeutic potential in osteogenesis by regulating cell cycle progression and promoting osteoblastic differentiation. Based on the similar biological process of osteo/odontoblastic differentiation, the present study evaluated the effects of CPC on odontoblastic differentiation of DPCs in vitro and in vivo, respectively. The morphology of CPC was observed by scanning electron microscopy. Colony-forming units were used to assess the antibacterial activity. The effects of CPC on cell proliferation and odontoblastic differentiation of human dental pulp cells (hDPCs) were also measured. Histological staining was performed to observe the reparative dentin formation in rat molars. In vitro, results of antibacterial studies showed that CPC significantly inhibited the growth of Streptococcus mutans. The appropriate concentration of CPC extract showed low cytotoxicity on hDPCs. Furthermore, CPC extract also promoted odontoblastic differentiation and mineralization compared with the control group, as shown by a dynamic increase in the expression of odontogenic marker genes and the increased number of mineralized nodules at 21 days. The pulpotomy models with CPC facilitated the formation of dentin bridge with the highly expressed dentin matrix protein 1 (DMP1) in odontoblast-like cells. In conclusion, the favorable biocompatibility, antibacterial property and bio-inductivity of CPC suggest that CPC can be used as a promising direct pulp capping material.

Sustained zinc release in cooperation with CaP scaffold promoted bone regeneration via directing stem cell fate and triggering a pro-healing immune stimuli

Metal ions have been identified as important bone metabolism regulators and widely used in the field of bone tissue engineering, however their exact role during bone regeneration remains unclear. Herein, the aim of study was to comprehensively explore the interactions between osteoinductive and osteo-immunomodulatory properties of these metal ions. In particular, the osteoinductive role of zinc ions (Zn²⁺), as well as its interactions with local immune microenvironment during bone healing process, was investigated in this study using a sustained Zn²⁺ delivery system incorporating Zn²⁺ into β-tricalcium phosphate/poly(L-lactic acid) (TCP/PLLA) scaffolds. The presence of Zn²⁺ largely enhanced osteogenic differentiation of periosteum-derived progenitor cells (PDPCs), which was coincident with increased transition from M1 to M2 macrophages (M\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varphi $$\end{document}φs). We further confirmed that induction of M2 polarization by Zn²⁺ was realized via PI3K/Akt/mTOR pathway, whereas marker molecules on this pathway were strictly regulated by the addition of Zn²⁺. Synergically, this favorable immunomodulatory effect of Zn²⁺ further improved the osteogenic differentiation of PDPCs induced by Zn²⁺ in vitro. Consistently, the spontaneous osteogenesis and pro-healing osteoimmunomodulation of the scaffolds were thoroughly identified in vivo using a rat air pouch model and a calvarial critical-size defect model. Taken together, Zn²⁺-releasing bioactive ceramics could be ideal scaffolds in bone tissue engineering due to their reciprocal interactions between osteoinductive and immunomodulatory characteristics. Clarification of this synergic role of Zn²⁺ during osteogenesis could pave the way to develop more sophisticated metal-ion based orthopedic therapeutic strategies.

Biocompatibility of a HA/β-TCP/C Scaffold as a Pulp-Capping Agent for Vital Pulp Treatment: An In Vivo Study in Rat Molars

Bioceramic materials possess desirable biological properties, highlighting their non-reactivity and osteoconductivity. Their use has been extended in vital pulp treatment. The purpose of this study was to evaluate and compare the effects of beta-tricalcium phosphate (β-TCP), hydroxyapatite (HA), and collagen (C) scaffold with mineral trioxide aggregate (MTA) on the vital pulp of rat molars. Thirty-two molars of Sprague–Dawley rats underwent direct pulp capping with β-TCP/HA/C (n = 16) and MTA (n = 16). After 30 days, the following parameters were evaluated in the tested samples: the degree of pulp inflammation and pulp vitality, the presence of reparative dentin, the homogeneity of the odontoblastic layer, and the presence of pulp fibrosis. No statistically significant differences were observed between HA/β-TCP/C and MTA in terms of the degree of inflammation (p = 0.124). Significant differences were found in reparative dentin formation between the treatment groups (p = 0.0005). Dentin bridge formation was observed in the MTA-treated group. The local action of HA/β-TCP/C is similar to that of MTA when used as an agent for pulp vital treatment in terms of absence of inflammation and maintenance of pulp vitality, although there are significant differences between both materials regarding the formation of dentin bridges.