Comparison of acidic fibroblast growth factor on collagen carrier with calcium hydroxide as pulp capping agents in monkeys

The Role of Growth Factor Delivery Systems on Cellular Activities of Dental Stem Cells: A Systematic Review (Part II)

OBJECTIVE

The current systematic review aims to provide the available ex vivo evidence evaluating the biological interactions of dental stem cells (DSCs) and growth factor delivery systems.

METHODS

Following the Preferred Reporting Items for a Systematic Reviews and Meta-Analyses (PRISMA) guidelines, systematic search was conducted in the electronic databases (PubMed/Medline, Scopus, Web of Science, and Google Scholar) up to January 2022. Studies evaluating the biological interactions of DSCs and growth factor delivery systems were included. The outcome measures were cell cytocompatibility, mineralization, and differentiation.

RESULTS

Sixteen studies were selected for the qualitative synthesis. The following growth factor delivery systems exhibit adequate cytocompatibility, enhanced mineralization, and osteo/odontoblast differentiation potential of DSCs: 1) Fibroblast growth factor (FGF-2)-loaded-microsphere and silk fibroin, 2) Bone morphogenic protein-2 (BMP-2)-loaded-microsphere and mesoporous calcium silicate scaffold, 3) Transforming growth factor Beta 1 (TGF-ß1)-loaded-microsphere, glass ionomer cement (GIC), Bio-GIC and liposome, 4) TGF-ß1-loaded-nanoparticles/scaffold, 5) Vascular endothelial growth factor (VEGF)-loaded-fiber and hydrogel, 6) TGF-ß1/VEGF-loaded-nanocrystalline calcium sulfate/hydroxyapatite/calcium sulfate, 7) Epidermal growth factor-loaded- nanosphere, 8) Stem cell factor/DSCs-loaded-hydrogel and Silk fibroin, 9) VEGF/BMP-2/DSCs-loaded-Three-dimensional matrix, 10) VEGF/DSCs-loaded-microsphere/hydrogel, and 11) BMP-2/DSCs and VEGF/DSCs-loaded-Collagen matrices. The included delivery systems showed viability, except for Bio-GIC on day 3. The choice of specific growth factors and delivery systems (i.e., BMP-2-loaded-microsphere and VEGF-loaded-hydrogel) resulted in a greater gene expression.

CONCLUSIONS

This study, with low-level evidence obtained from ex vivo studies, suggests that growth factor delivery systems induce cell proliferation, mineralization, and differentiation toward a therapeutic potential in regenerative endodontics.

The Regenerative Potential of bFGF in Dental Pulp Repair and Regeneration

Regenerative endodontic therapy intends to induce the host’s natural wound-healing process, which can restore the vitality, immunity, and sensitivity of the inflammatory or necrotic pulp tissue destroyed by infection or trauma. Myriads of growth factors are critical in the processes of pulp repair and regeneration. Among the key regulatory factors are the fibroblast growth factors, which have turned out to be the master regulators of both organogenesis and tissue homeostasis. Fibroblast growth factors, a family composed of 22 polypeptides, have been used in tissue repair and regeneration settings, in conditions as diverse as burns, ulcers, bone-related diseases, and spinal cord injuries. Meanwhile, in dentistry, the basic fibroblast growth factor is the most frequently investigated. Thereby, the aim of this review is 2-fold: 1) foremost, to explore the underlying mechanisms of the bFGF in dental pulp repair and regeneration and 2) in addition, to shed light on the potential therapeutic strategies of the bFGF in dental pulp–related clinical applications.

Evaluation of Chitosan Hydrogel for Sustained Delivery of VEGF for Odontogenic Differentiation of Dental Pulp Stem Cells

The pulpotomy with pulp capping is aimed at retaining vital pulp with reparative dentin formation. Vascular endothelial growth factor (VEGF) plays a crucial role in dentin regeneration; however, its constant administrations in the human body is still problematic. Chitosan was widely studied as an effective carrier to deliver bioactive molecules in regenerative medicine. In this study, we conducted a chitosan/β-glycerophosphate (CS/β-GP) hydrogel as a VEGF-sustained release system and explored its effects on dental pulp stem cells (DPSCs). CS/β-GP hydrogel was manufactured using a sol-gel method. SEM assay showed the spongy and porous microstructure of the lyophilized hydrogels. DPSCs cultured in the CS/β-GP hydrogel kept adhesion and vitality. CCK-8 assay tested the promoted proliferation activity of DPSCs on the hydrogel. Besides, the added VEGF protein could continually release from VEGF/CS/β-GP hydrogel. The VEGF/CS/β-GP hydrogel could promote the odontogenic differentiation of DPSCs better than VEGF treatment without hydrogel. Our results suggested that CS/β-GP hydrogel could continually release VEGF and contribute to odontogenic differentiation of DPSCs, thus may become a potential carrier of bioactive molecules in pulp capping therapy.

The Effect of Calendula officinalis on Oxidative Stress and Bone Loss in Experimental Periodontitis

Periodontitis is associated with reduced antioxidant capacity and increased oxidative damage. Oxidative stress induces inflammation and bone loss contributing to the pathological progression of periodontal disease. Calendula officinalis (CLO) has demonstrated anti-inflammatory and anti-oxidant activities. Therefore, the aim of this study was to evaluate the effect of CLO on oxidative stress and bone loss in rats subjected to experimental periodontitis (EP). For this, 72 male Wistar rats were divided into groups: Naïve, Saline (SAL) and CLO. Rats received SAL or CLO (90 mg/kg) 30 min before ligature and daily until the 11th day. Naïve group experienced no manipulation. After 11 days, the animals were euthanized and left maxillae collected for macroscopic analysis of alveolar bone loss (ABL). Periodontium was analyzed by macroscopy, scanning electron microscopy; confocal and light polarized microscopy. Immunohistochemical examination of DKK1, WNT 10b and β-catenin was performed. The gingival tissue was collected to reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) analyses. The 11 days of ligature induced bone loss, breakdown of collagen fibers, increased the immunostaining DKK-1 while reduced WNT 10b and β-catenin expressions. Periodontitis reduced GSH, SOD, CAT and increase MDA. All findings were reversed by 90 mg/kg of CLO. In summary our findings demonstrated that CLO reduced oxidative stress and bone loss and preserved collagen fibers in rats with EP, with participation of WNT signaling pathway.

Could the application of bioactive molecules improve vital pulp therapy success? A systematic review

This study aimed to systematically review the literature of animal studies to evaluate whether bioactive dentin proteins could improve vital pulp therapy success. The review is reported in accordance with the PRISMA Statement. Two reviewers independently conducted a literature search of seven databases: PubMed (Medline), Lilacs, IBECS, BBO, Web of Science, Scopus, and SciELO. Animal experiments in which bioactive dentin proteins were applied directly or indirectly to the pulp tissue were included. Data regarding the characteristics of the proteins evaluated, the delivery systems used and the main findings from each study were tabulated to assess the outcomes of interest (tertiary dentin formation, inflammatory response, intratubular mineralization). After screening, 32 papers were subjected to qualitative analysis. In 75% of the studies, direct pulp capping was performed. Additionally, the most studied proteins were BMP-7, TGF-β1, and extracted soluble dentin matrix proteins. In conclusion, there is evidence in the literature suggesting that bioactive dentin molecules could enhance tertiary dentin formation with fewer initial inflammatory responses in direct and indirect pulp therapy in animal models. There are potential areas to be explored for novel therapeutic approaches for dental tissue repair and regeneration with bioactive materials. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 941-956, 2017.

Role of angiogenesis in endodontics: contributions of stem cells and proangiogenic and antiangiogenic factors to dental pulp regeneration

INTRODUCTION

Dental pulp regeneration is a part of regenerative endodontics, which includes isolation, propagation, and re-transplantation of stem cells inside the prepared root canal space. The formation of new blood vessels through angiogenesis is mandatory to increase the survival rate of re-transplanted tissues. Angiogenesis is defined as the formation of new blood vessels from preexisting capillaries, which has great importance in pulp regeneration and homeostasis. Here the contribution of human dental pulp stem cells and proangiogenic and antiangiogenic factors to angiogenesis process and regeneration of dental pulp is reviewed.

METHODS

A search was performed on the role of angiogenesis in dental pulp regeneration from January 2005 through April 2014. The recent aspects of the relationship between angiogenesis, human dental pulp stem cells, and proangiogenic and antiangiogenic factors in regeneration of dental pulp were assessed.

RESULTS

Many studies have indicated an intimate relationship between angiogenesis and dental pulp regeneration. The contribution of stem cells and mechanical and chemical factors to dental pulp regeneration has been previously discussed.

CONCLUSIONS

Angiogenesis is an indispensable process during dental pulp regeneration. The survival of inflamed vital pulp and engineered transplanted pulp tissue are closely linked to the process of angiogenesis at sites of application. However, the detailed regulatory mechanisms involved in initiation and progression of angiogenesis in pulp tissue require investigation.

Expression of Small Integrin-Binding LIgand N-linked Glycoproteins (SIBLINGs) in the reparative dentin of rat molars

AIM

To analyze the expression and distribution of Small Integrin-Binding LIgand N-linked Glycoproteins (SIBLINGs) in reparative dentin (RepD).

METHODOLOGY

Cavities on the mesial surfaces of rat molars were prepared to expose the pulp, and a calcium hydroxide agent was applied to cap the exposed pulp. The molars with pulp capping were extracted at postoperative 1, 2, and 4 weeks. The immunolocalization of four SIBLINGs, dentin matrix protein 1 (DMP1), dentin sialoprotein (DSP), bone sialoprotein (BSP), and osteopontin (OPN) in RepD, was analyzed in comparison with reactionary dentin (ReaD) and primary dentin (PD).

RESULTS

At two weeks after operation, the region of the exposed pulp formed a layer of reparative dentin bridge sealing the communication between the cavity and pulp chamber. Dentinal tubules in RepD were more irregular in shape and fewer in number than PD. At postoperative 2 and 4 weeks, RepD had lower levels of DMP1 and DSP than PD. BSP and OPN were present in RepD, but not in PD. RepD showed certain similarities to ReaD in the expression of SIBLINGs.

CONCLUSIONS

The reduced levels of DMP1 and DSP may be associated with the decreased number of dentinal tubules in RepD. The expression of BSP and OPN in RepD indicates that the odontoblast-like cells were attempting to produce a hard tissue at a very rapid pace. These findings suggest that in response to the surgical injury, the newly differentiated odontoblast-like cells altered their synthesis of the dentinogenesis-related proteins and produced a hard tissue that is an intermediate between dentin and bone.

Direct pulp capping with a self-etching adhesive system: histopathologic evaluation in dogs' teeth

OBJECTIVE

This study evaluated histopathologically the response of pulp and periradicular tissues after pulp capping with an all-in-one self-etching adhesive system in dogs' teeth.

STUDY DESIGN

Forty teeth of 4 dogs were assigned to 3 groups according to the pulp capping material: G1 (n = 20): self-etching adhesive system; G2 (n = 10): Ca(OH)(2); G3 (n = 10): zinc oxide-eugenol. The animals were killed 7 and 70 days after pulp capping. The pieces containing the pulp-capped teeth were removed and processed for histologic analysis.

RESULTS

At 7 days, no dentin bridge formation was observed; G1 and G3 exhibited inflammatory pulpal alterations, whereas G2 presented only mild inflammatory infiltrate in the pulp tissue adjacent to the capping material, the remainder being intact. At 70 days, no specimen in G1 or G3 presented dentin bridge formation. The remaining pulp tissue exhibited severe inflammatory alterations and areas of necrosis. In G2, all specimens showed dentin bridge formation and absence of inflammation and mineralized tissue resorption. No bacteria were identified using Brown and Brenn staining techniques in all 3 groups at any observation period.

CONCLUSION

According to the conditions of this study, direct pulp capping with the self-etching adhesive system did not allow pulp tissue repair and failed histopathologically in 100% of the cases.