Effects of a Novel Bioactive Glass Composition on Biological Properties of Human Dental Pulp Stem Cells

Combination adipose-derived mesenchymal stem cells-demineralized dentin matrix increase bone marker expression in periodontitis rats

Background

Periodontal disease is common in both developed and developing countries and affects around 20-50% of the global population, especially in adolescents, adults and the elderly is a public health problem. ADMSCs have the advantage of regenerating damaged tissue with high quality. DDM in the form of slices can improve healing in the mandibular sockets of molar teeth. The combination of ADMSC-DDM is expected to accelerate bone regeneration.

Objectives

To analyze the combination of ADMSCs-DDM at increasing bone marker expression in periodontitis rats.

Methods

This research is experimental with a randomized control group post-test-only design. A total of 50 male Wistar rats were divided into four groups: 1) normal group (K); 2) CP model (K + ); 3) CP model and treated with DDM scaffold therapy (K(s)); 4) CP model and treated with ADMSCs-DDM combination therapy (K(sc)). Making a CP model with injected LPS P. gingivalis into interproximal gingiva of the right first and second lower molars. The in vivo research stage was the implantation of the DDM scaffold and the ADMSCs-DDM combination in the rat periodontal pocket. Rats were euthanized on days 7, 14, and 28, and immunohistochemistry of STRO-1, RUNX-2, OSX, COL-I, and OCN was performed. DDM scaffolds are made in 10%, 50% and 100% concentrations for MTT testing. Statistical results were analyzed with Kruskal-Wallis and Mann-Whitney tests.

Results

The results of the MTT scaffold DDM were significant in the 10%, 50%, and 100% dilution groups (p < 0.05). The results showed there was a substantial difference in the expression of STRO-1 between the study groups (p < 0.05). The (K(sc)) was significantly higher than the (K) in RUNX-2 expression (p < 0.05). OSX expression showed significant results between study groups (p < 0.05). The expression of OCN and COL-I showed a significant difference in all study groups on day 28, where the (K(sc)) was higher than the (K) (p < 0.05).

Conclusions

Administration of the ADMSCs-DDM combination can accelerate alveolar bone regeneration on day 28. There is a mechanism of alveolar bone regeneration through the STRO-1, RUNX-2, OSX, and the COL-I pathway in periodontitis models.

Strontium Carbonate and Strontium-Substituted Calcium Carbonate Nanoparticles Form Protective Deposits on Dentin Surface and Enhance Human Dental Pulp Stem Cells Mineralization

Strontium acetate is applied for dental hypersensitivity treatment; however, the use of strontium carbonates for this purpose has not been described. The use of Sr-carbonate nanoparticles takes advantage of both the benefits of strontium on dentin mineralization and the abrasive properties of carbonates. Here in, we aimed to synthesize strontium carbonate and strontium-substituted calcium carbonate nanoparticles and test them as potential compounds in active dentifrices for treating dental hypersensitivity. For this, SrCO₃, Sr_0.5Ca_0.5CO₃, and CaCO₃ nanoparticles were precipitated using Na₂CO₃, SrCl₂, and/or CaCl₂ as precursors. Their morphology and crystallinity were evaluated by electron microscopy (SEM) and X-ray diffraction, respectively. The nanoparticles were added to a poly (vinyl alcohol) gel and used to brush dentin surfaces isolated from human third molars. Dentin chemical composition before and after brushing was investigated by infrared spectroscopy (FTIR) and X-ray dispersive energy spectroscopy. Dentin tubule morphology, obliteration, and resistance of the coatings to acid attack were investigated by SEM and EDS. The cytotoxicity and ability of the particles to trigger the mineralization of hDPSCs in vitro were studied. Dentin brushed with the nanoparticles was coated by a mineral layer that was also able to penetrate the tubules, while CaCO₃ remained as individual particles on the surface. FTIR bands related to carbonate groups were intensified after brushing with either SrCO₃ or Sr_0.5Ca_0.5CO₃. The shift of the phosphate-related FTIR band to a lower wavenumber indicated that strontium replaced calcium on the dentin structure after treatment. The coating promoted by SrCO₃ or Sr_0.5Ca_0.5CO₃ resisted the acid attack, while calcium and phosphorus were removed from the top of the dentin surface. The nanoparticles were not toxic to hDPSCs and elicited mineralization of the cells, as revealed by increased mineral nodule formation and enhanced expression of COL1, ALP, and RUNX2. Adding Sr_0.5Ca_0.5CO₃ as an active ingredient in dentifrices formulations may be commercially advantageous since this compound combines the well-known abrasive properties of calcium carbonate with the mineralization ability of strontium, while the final cost remains between the cost of CaCO₃ and SrCO₃. The novel Sr_0.5Ca_0.5CO₃ nanoparticles might emerge as an alternative for the treatment of dental hypersensitivity.

Effect of microtopography on osseointegration of implantable biomaterials and its modification strategies

Orthopedic implants are widely used for the treatment of bone defects caused by injury, infection, tumor and congenital diseases. However, poor osseointegration and implant failures still occur frequently due to the lack of direct contact between the implant and the bone. In order to improve the biointegration of implants with the host bone, surface modification is of particular interest and requirement in the development of implant materials. Implant surfaces that mimic the inherent surface roughness and hydrophilicity of native bone have been shown to provide osteogenic cells with topographic cues to promote tissue regeneration and new bone formation. A growing number of studies have shown that cell attachment, proliferation and differentiation are sensitive to these implant surface microtopography. This review is to provide a summary of the latest science of surface modified bone implants, focusing on how surface microtopography modulates osteoblast differentiation in vitro and osseointegration in vivo, signaling pathways in the process and types of surface modifications. The aim is to systematically provide comprehensive reference information for better fabrication of orthopedic implants.

Evaluation of Antimicrobial Effect of Air-Polishing Treatments and Their Influence on Human Dental Pulp Stem Cells Seeded on Titanium Disks

Dental implants are one of the most frequently used treatment options for tooth replacement, and titanium is the metal of choice due to its demonstrated superiority in resisting corrosion, lack of allergic reactions and mechanical strength. Surface roughness of titanium implants favors the osseointegration process; nevertheless, its topography may provide a suitable substrate for bacterial biofilm deposition, causing peri-implantitis and leading to implant failure. Subgingival prophylaxis treatments with cleansing powders aimed to remove the bacterial accumulation are under investigation. Two different air-polishing powders—glycine and tagatose—were assayed for their cleaning and antimicrobial potential against a Pseudomonas biofilm and for their effects on human dental pulp stem cells (hDPSCs), seeded on sandblasted titanium disks. Immunofluorescence analyses were carried out to evaluate cell adhesion, proliferation, stemness and osteogenic differentiation. The results demonstrate that both the powders have a great in vitro cleaning potential in the early period and do not show any negative effects during hDPSCs osteogenic differentiation process, suggesting their suitability for enhancing the biocompatibility of titanium implants. Our data suggest that the evaluated cleansing systems reduce microbial contamination and allow us to propose tagatose as an adequate alternative to the gold standard glycine for the air-polishing prophylaxis treatment.

A New Generation of Electrospun Fibers Containing Bioactive Glass Particles for Wound Healing

Chitosan fibers blended with polyethylene oxide (CHIT_PEO) and crosslinked with genipin were fabricated by electrospinning technique. Subsequently, CHIT_PEO bioactive glass composite electrospun mats were fabricated with the aim to achieve flexible structures with adequate mechanical properties and improved biological performance respect to CHIT_PEO fibers, for potential applications in wound healing. Three different compositions of bioactive glasses (BG) were selected and investigated: 45S5 BG, a Sr and Mg containing bioactive glass (BGMS10) and a Zn-containing bioactive glass (BGMS_2Zn). Particulate BGs (particles size < 20 μm) were separately added to the starting CHIT_PEO solution before electrospinning. The two recently developed bioactive glasses (BGMS10 and BGMS_2Zn) showed very promising biological properties in terms of bioactivity and cellular viability; thus, such compositions were added for the first time to CHIT_PEO solution to fabricate composite electrospun mats. The incorporation of bioactive glass particles and their distribution into CHIT_PEO fibers were assessed by SEM and FTIR analyses. Furthermore, CHIT_PEO composite electrospun mats showed improved mechanical properties in terms of Young’s Modulus compared to neat CHIT_PEO fibers; on the contrary, the values of tensile strain at break (%) were comparable. Biological performance in terms of cellular viability was investigated by means of WST-8 assay and CHIT_PEO composite electrospun mats showed cytocompatibility and the desired cellular viability.

A Review of Bioactive Glass/Natural Polymer Composites: State of the Art

Collagen, gelatin, silk fibroin, hyaluronic acid, chitosan, alginate, and cellulose are biocompatible and non-cytotoxic, being attractive natural polymers for medical devices for both soft and hard tissues. However, such natural polymers have low bioactivity and poor mechanical properties, which limit their applications. To tackle these drawbacks, collagen, gelatin, silk fibroin, hyaluronic acid, chitosan, alginate, and cellulose can be combined with bioactive glass (BG) nanoparticles and microparticles to produce composites. The incorporation of BGs improves the mechanical properties of the final system as well as its bioactivity and regenerative potential. Indeed, several studies have demonstrated that polymer/BG composites may improve angiogenesis, neo-vascularization, cells adhesion, and proliferation. This review presents the state of the art and future perspectives of collagen, gelatin, silk fibroin, hyaluronic acid, chitosan, alginate, and cellulose matrices combined with BG particles to develop composites such as scaffolds, injectable fillers, membranes, hydrogels, and coatings. Emphasis is devoted to the biological potentialities of these hybrid systems, which look rather promising toward a wide spectrum of applications.