The effects and potential applications of concentrated growth factor in dentin-pulp complex regeneration

Outcome of regenerative endodontic procedures in delayed replanted immature permanent teeth with apical periodontitis: A retrospective study

BACKGROUND

Regenerative endodontic procedures (REPs) is effective for treating young permanent teeth with pulp necrosis. However, its efficacy on delayed replanted avulsed teeth is unclear.

AIM

This retrospective study aimed to assess the efficacy of REPs in treating delayed replanted immature permanent teeth with apical periodontitis.

DESIGN

Avulsed teeth receiving REPs were systematically screened based on predetermined criteria. This study assessed the REP outcomes, postoperative periodontal healing, and overall treatment efficacy. Samples were grouped by REP outcomes and root development stage, with Fisher's exact tests used to compare outcomes among different groups.

RESULTS

Among the included 17 teeth, 47.1% exhibited successful REPs and periodontal healing. Another 47.1%, due to replacement resorption or REP failure, were categorized as tooth survival. Healing of periapical lesions was observed in 88.2% of the cases, but only 41.2% demonstrated continued root development. Although differences were not significant (p = 0.05), teeth with continued root development had a higher rate of functional healing (85.7%) compared to those without (30%).

CONCLUSION

Within the limitations of this study, REPs presented reliable outcomes for treating delayed replanted immature permanent teeth with apical periodontitis mainly in periapical lesion healing. Teeth with continued root development after REPs exhibited a higher rate of functional healing. Further investigation is required to explore potential synergies between REP outcomes and periodontal healing.

Efficacy and mechanisms of concentrated growth factor on facial nerve rehabilitation in a rabbit model

Accelerated rehabilitation following facial nerve injury presents unique clinical challenges. This study evaluates the therapeutic effects of concentrated growth factor (CGF) on facial nerve recovery in a rabbit model and on RSC96 Schwann cells. Characterization of the CGF membrane (CGFM) revealed a three-dimensional fibrin network with embedded platelets, and representative growth factors, including TGF-β1, PDGF-BB, IGF-1, bFGF, and VEGF, were detected. In vivo, the Crush + CGFM group exhibited enhanced axon and myelin regeneration, increased Schwann cell proliferation, and improved facial nerve function compared to the Crush group. In vitro, CGF treatment significantly promoted the proliferation and migration of RSC96 cells and facilitated axon elongation in NG108-15 cells compared to controls. Mechanistically, CGF treatment led to a significant increase in PDGFRβ phosphorylation. Inhibition of this pathway with SU16f decreased Schwann cell activity and hindered overall nerve rehabilitation. These results underscore CGF's potential to accelerate nerve repair by promoting axon and myelin regeneration and enhancing Schwann cell biological activity, with the PDGFRβ pathway playing a crucial regulatory role. This study highlights CGF as a promising therapeutic strategy for improving facial nerve rehabilitation.

Intrinsic and extrinsic modulators of human dental pulp stem cells: advancing strategies for tissue engineering applications

This review focuses on dental pulp stem cells (DPSCs) which are mesenchymal stem cells (MSCs) and originating from the neural crest. These cells possess a high capacity for self-renewal and multilineage differentiation. Because of these traits, they represent promising sources for tissue engineering, regenerative medicine, and clinical applications. The objective of this study was to assess the extrinsic and intrinsic factors influencing DPSC characteristics and their potential in tissue engineering. This review discusses the external and internal factors affecting DPSC properties, including proliferation, migration, differentiation, and gene expression post extraction. Additionally, it explores the impact of the microenvironment-its composition and physical properties-and genetic and epigenetic regulation on DPSC behavior. Variations in the microenvironment and genetic regulation play pivotal roles in modulating DPSC functions, including their proliferation and differentiation potential. Intrinsic and extrinsic factors are key barriers to realizing the full therapeutic potential of DPSCs. A deeper understanding of the extrinsic and intrinsic factors affecting DPSC behavior is critical for optimizing their use in regenerative medicine, particularly for dental and craniofacial applications. Although DPSCs hold significant promise, challenges remain, and this review provides insights into the current limitations and future directions for DPSC-based therapies. Researchers and clinicians are offered a comprehensive resource for advancing the field.

Calcium Chloride vs. Mechanical Preparation of Fibrinogen-Depleted Human Platelet Lysate: Implications for Umbilical Cord Mesenchymal Stem Cell Culture

Fetal bovine serum (FBS) has long been the standard supplement in cell culture media, providing essential growth factors and proteins that support cell growth and differentiation. However, ethical concerns and rising costs associated with FBS have driven researchers to explore alternatives, particularly human platelet lysate (HPL). Among these alternatives, fibrinogen-depleted HPL (FD-HPL) has gained attention due to its reduced thrombogenicity, which minimizes the risk of clot formation in cell cultures and enhances the safety of therapeutic applications. This study investigates two preparation methods for FD-HPL from human platelet concentrates: the calcium chloride method and a mechanical approach. The concentrations of critical growth factors, including vascular endothelial growth factor (VEGF), brain-derived neurotrophic factor (BDNF), insulin-like growth factor (IGF), and keratinocyte growth factor (KGF), were evaluated for both methods. Additionally, the impact of FD-HPL on the proliferation and morphology of umbilical cord-derived mesenchymal stem cells (UC-MSCs) was assessed. The findings revealed that the calcium chloride method produced significantly higher concentrations of all measured growth factors compared to the mechanical method. Moreover, UC-MSCs cultured in calcium chloride-prepared FD-HPL exhibited enhanced cellular characteristics, including increased cell size, elongation, and improved overall morphology compared to those cultured in mechanically processed FD-HPL. These results indicate that the preparation method significantly influences the biological properties of HPL and the effectiveness of UC-MSC culture. The calcium chloride method emerges as a superior technique for producing FD-HPL, offering a promising alternative to FBS in regenerative medicine applications. This study underscores the importance of preparation methods in optimizing HPL for cell culture and therapeutic uses.

Development of a super-hydrophilic anaerobic tube for the optimization of platelet-rich fibrin

Horizontal platelet-rich fibrin (H-PRF) contains a variety of bioactive growth factors and cytokines that play a key role in the process of tissue healing and regeneration. The blood collection tubes used to produce Solid-PRF (plasmatrix (PM) tubes) have previously been shown to have a great impact on the morphology, strength and composition of the final H-PRF clot. Therefore, modification to PM tubes is an important step toward the future optimization of PRF. To this end, we innovatively modified the inner wall surface of the PM tubes with plasma and adjusted the gas environment inside the PM tubes to prepare super-hydrophilic anaerobic plasmatrix tubes (SHAP tubes). It was made anaerobic for the preparation of H-PRF with the aim of improving mechanical strength and bioactivity. The findings demonstrated that an anaerobic environment stimulated platelet activation within the PRF tubes. After compression, the prepared H-PRF membrane formed a fibrous cross-linked network with high fracture strength, ideal degradation characteristics, in addition to a significant increase in size. Thereafter, the H-PRF membranes prepared by the SHAP tubes significantly promoted collagen synthesis of gingival fibroblast and the mineralization of osteoblasts while maintaining excellent biocompatibility, and advantageous antibacterial properties. In conclusion, the newly modified PRF tubes had better platelet activation properties leading to better mechanical strength, a longer degradation period, and better regenerative properties in oral cell types including gingival fibroblast and alveolar osteoblasts. It also improves the success rate of H-PRF preparation in patients with coagulation dysfunction and expands the clinical application scenario.

Role of Concentrated Growth Factor on the Healing Outcome of Periapical Surgery: A Case Report

This case report highlights the use of concentrated growth factor (CGF) in enhancing healing outcomes following endodontic periapical surgery. A 57-year-old female came with pain and swelling related to chronic periapical abscesses in her lower front teeth, necessitating surgical intervention. Apicectomy combined with CGF application was considered as a treatment option. CGF, an advanced autologous platelet concentrate, offers superior healing properties due to its natural composition and absence of anticoagulants, making it a favorable option over earlier techniques like platelet-rich plasma (PRP) and platelet-rich fibrin (PRF). The surgical procedure, performed under an operating microscope, included meticulous debridement and the placement of a CGF membrane over the surgical site. Follow-up evaluations at six months and one year demonstrated significant healing, as evident clinically and radiographically. The present case indicated the potential of CGF as an effective adjunct in periapical surgery, promoting better healing and recovery in patients with challenging dental conditions. The findings support the growing interest in autologous biomaterials for regenerative dental procedures.

Concentrated Growth Factors for Managing a Nonvital Maxillary Central Incisor With an Open Apex

Apexification procedure on a necrotic, infected tooth with an open apex is achievable if the canal is adequately disinfected. This case report aims to add an endodontic case to the body of knowledge currently available on the application of concentrated growth factor (CGF). A 24-year-old man with a history of a fall 15 years earlier developed apical periodontitis and pulpal necrosis in his maxillary central incisor with an open apex. Following the preparation of the access cavity, a solution containing 20 mL of sodium hypochlorite solution (5.25%) and 10 mL of 0.2% chlorhexidine was used to irrigate the canal successfully, and paper points were used to dry it. The canal was covered with a calcium hydroxide dressing for 10 days. The patient's right antecubital vein yielded 10 mL of whole blood, from which CGF was made. After the removal of the intracanal dressing, the CGF was placed into the canal to act as apical matrix to stabilize the mineral trioxide aggregate. The canal underwent composite restoration after being obturated. One year later, the clinical examination showed that the tests for palpation and percussion were negative. Both the electric and cold pulp tests yielded positive results for the tooth. Regression of the periapical lesion was seen on radiographic evaluation. Our case report's findings lead us to the conclusion that, in certain circumstances, complete canal disinfection can be used to treat necrotic, infected immature teeth, and that CGF might make an excellent scaffold matrix for treating open apex cases.

Evaluating Autologous Platelet Aggregate as a Scaffold in the Treatment of Human Permanent Molars With Pulpitis: A Case Series

This case series aims to investigate the radiographic and clinical results of pulpotomy using concentrated growth factor (CGF), a scaffold obtained from the host, on adult human permanent molars. A total of four cases diagnosed with symptomatic reversible pulpitis based on history, clinical examination, and investigation were planned for CGF pulpotomy. Blood required for the procedure was collected in a 10 ml test tube without anticoagulants to produce CGF. Subsequently, the sample was promptly centrifuged using a tabletop centrifuge. The clot-free pulp chamber was then shielded with a small CGF membrane fragment. A layer of mineral trioxide aggregate (MTA), approximately 2 mm thick, was applied over the CGF membrane. Following this, the tooth was temporized with glass ionomer cement. The patients were scheduled for a follow-up visit after a day to assess postoperative discomfort and to proceed with the final composite restoration. All the patients were recalled at 6 and 12 months for follow-up. Three of the patients were clinically and radiographically asymptomatic following the treatment. The tooth demonstrated a normal periodontal ligament space on radiographic inspection, and it passed pulp sensibility tests. One patient, though, complained of excruciating discomfort 24 hours after the procedure. The favorable results of the three instances imply that more investigation is required to validate the application of this biocompatible alternative to the management of pulpitis in permanent human molar teeth. More research with larger sample numbers and longer recollection periods is required. The use of concentrated growth factor (CGF), derived from the patient's own blood, serves as an excellent biological scaffold for the treatment of pulpal diseases.

The effects of mineral trioxide aggregate and second-generation autologous growth factor on pulpotomy via TNF-α and NF-kβ/p65 pathways

This study aims to investigate the effect of Mineral Trioxide Aggregate (MTA), a bioactive endodontic cement, and Concentrated Growth Factor (CGF), a second-generation autologous growth factor, on pulpotomy-induced pulp inflammation. The study utilized the maxillary anterior central teeth of thirty-six young male Sprague Dawley rats. Forty-eight teeth were randomly assigned to two groups (12 rats/group; 24 teeth/group) based on the capping material (MTA or CGF). Subsequently, two subgroups (MTAG and CGFG) were formed per group (12 teeth/group) based on the time following pulpotomy (2-weeks and 4-weeks). The central teeth of the 12 animals assigned to the control group (CG) were not manipulated in any way, both in the 2-week group and in the 4-week group. Tissue samples extracted from rats at the end of the experiment were stained with H&E for histopathological analysis. For immunohistochemical analysis, primary antibodies for TNF-α and NF-kβ/65 were incubated. Data obtained from semi-quantitative analysis were assessed for normal distribution using Skewness-Kurtosis values, Q-Q plot, Levene's test, and the Shapiro-Wilk test on statistical software. A P value < 0.05 was considered significant. When compared with the control group, both MTAG and CGFG showed increased edematous and inflammatory areas. In MTAG, edematous and inflammatory areas decreased significantly from the 2nd week (2(2-2), 2(1-2)) to the 4th week (1(1-1), 1(0-1)), while in CGFG, edematous areas decreased (2(2-3), 1.5(1-2)), and inflammatory areas increased significantly (2(2-3), 3(2-2.5)). When compared with the control group, TNF-α and NF-kβ/p65 positivity were higher in both MTAG and CGFG. In MTAG, TNF-α [2(1.5-2)] and NF-kβ/p65 [1.5(1-2)] positivity decreased significantly from the 2nd week to the 4th week [TNF-α: 1(1-1), NF-kβ/p65: 1(1-2)], while no significant change was observed in CGFG. In conclusion, this study revealed a reduction in cells showing TNF-α and NF-kβ/p65 positivity in the MTA treatment group compared to the CGF group. Although MTA demonstrated more favorable results than CGF in mitigating pulpal inflammation within the scope of this study, further experimental and clinical investigations are warranted to obtain comprehensive data regarding CGF.

Concentrated growth factor and collagen as barrier materials in alveolar ridge preservation for posterior teeth: a prospective cohort study with one-year follow-up

OBJECTIVES

This study aims to evaluate the efficacy of concentrated growth factor (CGF) membrane and collagen as barrier materials in sealing the alveolar socket in alveolar ridge preservation (ARP) in the posterior region during a one-year follow-up.

METHODS

A total of 24 patients who underwent ARP in the posterior region were selected for inclusion and randomly assigned to the CGF group (12 cases) and Collagen group (12 cases). The patients in both groups underwent extraction of posterior teeth. The extraction sockets were filled with a bone substitute to the level of the pre-extraction buccal and lingual or palatal alveolar bone plates. The wounds in the CGF group were closed with a fabricated CGF overlaying the upper edge of the bone substitute material, whereas those in the Collagen group were closed with Bio-Oss Collagen. The implants were placed after 6 months. The evaluation was based on implant retention, re-grafting rate, and vertical and horizontal alveolar ridge bone volume changes measured by cone beam computed tomography (CBCT). Data were statistically analyzed using SPSS 28.0 software.

RESULTS

No patient withdrew throughout the follow-up period. No implant failure and no severe peri-implant or mucosal soft tissue complications were observed. Six months after the operation, the degree of vertical alveolar ridge height resorption in the CGF group was lower than that in the Collagen group (P<0.05). There were no statistically difference between the groups at 1 year after the operation (P>0.05). The amount of bone reduction in horizontal alveolar ridge width showed no difference between the groups at 6 months and 1 year after surgery (P>0.05).

CONCLUSIONS

CGF membrane and Bio-Oss Collagen as barrier materials for posterior ARP inhibited reduction in alveolar ridge bone mass.

Acemannan-containing bioactive resin modified glass ionomer demonstrates satisfactory physical and biological properties

Background/purpose

Resin-modified glass ionomers (RMGIs) have been recommended as liner and cement to provide the teeth with mechanical support, a chemical barrier, and thermal insulation. Acemannan, the main polysaccharide extracted from Aloe vera, is a promising inductive material in vitro and in vivo. This study aimed to develop acemannan-containing bioactive resin-modified glass ionomers (RMGIs).

Materials and methods

Acemannan (3%, 5%, and 10%) was added to the three types of RMGIs (RU-HBM1/Fuji II LC/Vitrebond) to generate 3%, 5%, and 10% aceRMGIs (aceRU/aceFuji/aceVB). The materials were evaluated for depth of cure/flexural strength/cumulative fluoride ion release. Cell viability and vascular endothelial growth factor (VEGF) and bone morphogenetic protein-2 (BMP-2) secretion were determined using MTT/apoptosis/necrosis assays, and ELISA kits, respectively. RMGI without acemannan were used as controls.

Results

The aceRMGIs met the ISO requirements for depth of cure and flexural strength. Adding 10% acemannan increased the cumulative fluoride release in the RU and FJ groups, but slightly decreased it in the VB group (P < 0.05). The MTT assay revealed 10% aceRU and all aceFJ groups significantly increased cell viability compared with each control group (P < 0.05). Apoptosis/necrosis assay showed the biocompatibility of all aceRMGIs. Adding acemannan to RMGIs significantly induced VEGF expression in a dose dependent manner while 5% and 10% aceRU significantly induced BMP-2 expression compared with RU group (P < 0.05).

Conclusion

We conclude that 5-10% acemannan in RMGI is the optimal concentration based on its physical properties and ability to induce pulp cell proliferation and growth factor secretion.

Fundamentals and Translational Applications of Stem Cells and Biomaterials in Dental, Oral and Craniofacial Regenerative Medicine

Regenerative dental medicine continuously expands to improve treatments for prevalent clinical problems in dental and oral medicine. Stem cell based translational opportunities include regenerative therapies for tooth restoration, root canal therapy, and inflammatory processes (e.g., periodontitis). The potential of regenerative approaches relies on the biological properties of dental stem cells. These and other multipotent somatic mesenchymal stem cell (MSC) types can in principle be applied as either autologous or allogeneic sources in dental procedures. Dental stem cells have distinct developmental origins and biological markers that determine their translational utility. Dental regenerative medicine is supported by mechanistic knowledge of the molecular pathways that regulate dental stem cell growth and differentiation. Cell fate determination and lineage progression of dental stem cells is regulated by multiple cell signaling pathways (e.g., WNTs, BMPs) and epigenetic mechanisms, including DNA modifications, histone modifications, and non-coding RNAs (e.g., miRNAs and lncRNAs). This review also considers a broad range of novel approaches in which stem cells are applied in combination with biopolymers, ceramics, and composite materials, as well as small molecules (agonistic or anti-agonistic ligands) and natural compounds. Materials that mimic the microenvironment of the stem cell niche are also presented. Promising concepts in bone and dental tissue engineering continue to drive innovation in dental and non-dental restorative procedures.

Effects of Growth Factors on the Differentiation of Dental Stem Cells: A Systematic Review and Meta-analysis (Part I)

INTRODUCTION

To evaluate the biological interaction between dental stem cells (DSCs) and different growth factors in the field of regenerative endodontics.

METHODS

A systematic search was conducted in the electronic databases up to October 2021. This study followed the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Ex vivo studies evaluating the biological interactions of DSCs and growth factors were included. The meta-analysis was performed according to the type of growth factor. The outcomes were cell viability/ proliferation and mineralization. Standardized mean differences (SMDs) were estimated using the random-effect maximum-likelihood method (P < .05). Additional analysis was performed to find any potential source of heterogeneity.

RESULTS

Twenty articles were included in the systematic review; meta-analysis was performed for fibroblast growth factor-2 (FGF-2) and Transforming growth factor-ß1 (TGF-β1) (n = 5). Results showed that use of FGF-2 significantly increased cell proliferation on day 1-(SMD = 3.56, P = 0.00), 3-(SMD = 9.04, P = 0.00), 5-(SMD = 8.37, P = 0.01), and 7 (SMD=8.51, P=0.00) than the control group. TGF-ß1 increased alkaline phosphatase (ALP) activity more than control only on day 3 (SMD = 3.68, P = 0.02). TGF-β1 had no significant effect on cell proliferation on days 1 and 3 (P > 0.05) and on ALP activity on days 5 and 7 (P > 0.05). Meta-regression analysis showed that different covariates (i.e., cell type, passage number, and growth factors' concentration) could significantly influence the effect sizes at different follow- ups (P < 0.05).

CONCLUSION

Specific growth factors might enhance the proliferation and mineralization of DSCs; however, the obtained evidence was weak. Due to the high heterogeneity among the included studies, other growth factors' inhibitory/stimulatory effects on DSCs could not be evaluated.

Efficacy of concentrated growth factor (CGF) in the surgical treatment of oral diseases: a systematic review and meta-analysis

BACKGROUND

Concentrated growth factor (CGF), a new autologous platelet concentrate, has been widely investigated to the adjunctive treatment of oral diseases. This study aims to evaluate the efficacy of CGF in the surgical treatment of oral diseases.

METHODS

MEDLINE, Web of Science, Scopus, Cochrane, and EMBASE databases were searched up to July 2023. Only randomized clinical trials were included. The methodologic quality was evaluated by the Cochrane Risk of Bias Tool. RevMan 5.4 software was used for data analysis.

RESULTS

In the treatment of periodontal intrabony defects, bone graft combined with CGF was significantly superior to bone graft (P < 0.01), with mean intrabony defect depth reduction of 1.41 mm and mean clinical attachment level gain of 0.55 mm. In the regenerative surgery of furcation defects, the effect of CGF group was significantly better than control group (P < 0.0001), with mean probing depth reduction of 0.99 mm, vertical bone gain of 0.25 mm, and horizontal bone gain of 0.34 mm. CGF combined with coronally advanced flap (CAF) was more effective than CAF alone (mean keratinized tissue width increase of 0.41 mm, mean gingival thickness increase of 0.26 mm, P < 0.00001), but less effective than connective tissue graft (CTG) combined with CAF (mean root coverage difference of -15.1%, mean gingival thickness difference of -0.5 mm, P < 0.0001). In the alveolar ridge preservation, additional use of CGF reduced horizontal bone resorption by 1.41 mm and buccal vertical bone resorption by 1.01 mm compared to control group (P < 0.0001). The VAS score of CGF group was significantly lower than that of the control group at the 1st and 7th day after oral surgery (P < 0.0001).

CONCLUSIONS

CGF can exert a positive adjunctive effect for the regenerative surgery of periodontal intrabony defects, furcation defects, and alveolar ridge preservation procedure. CGF combined with CAF has a better therapeutic effect on gingival recession compared to CAF alone, although it is not as effective as CTG combined with CAF. CGF could promote postoperative healing and pain relief in oral surgery within a week. There is currently not enough evidence to support the clinical benefits of CGF in other oral surgeries.

Evaluation of concentrated growth factor and blood clot as scaffolds in regenerative endodontic procedures: A retrospective study

The study aims to investigate and compare the success rate of concentrated growth factor (CGF) and blood clot (BC) as scaffolds in regenerative endodontic procedures (REPs). Immature permanent necrotic teeth treated by REPs with at least a 6-month follow-up were included. These teeth were divided into the CGF (53 teeth) and BC (68 teeth) groups. Treatment outcomes were assessed using a combined clinical and radiographic scoring system. The total success rate was 91.74% over a mean follow-up period of 23.15 months. There was no significant difference between the CGF group (86.79%) and BC group (95.59%). The success rate of traumatic teeth (84.31%) was significantly lower than that of teeth with developmental dental anomalies (98.39%) (p < 0.05). CGF may be a suitable alternative scaffold in REPs when adequate bleeding cannot be achieved. Moreover, compared to developmental dental anomalies, traumatic teeth treated by REPs may be more vulnerable to failure.

The efficacy of concentrated growth factor and platelet-rich fibrin as scaffolds in regenerative endodontic treatment applied to immature permanent teeth: a retrospective study

BACKGROUND

The aim of this retrospective study was to compare the efficacy of concentrated growth factor (CGF) and platelet-rich fibrin (PRF) as scaffolds in regenerative endodontic therapy (RET).

METHODS

Necrotic immature permanent teeth treated with regenerative endodontic therapy during January 2018 to August 2022 were divided into the CGF and PRF groups according to the scaffold. The CGF and PRF groups included 7 and 6 teeth, respectively. The efficacy of regenerative endodontic therapy was analyzed based on the clinical and radiological outcomes at three different follow up periods: T1 (3-6 months), T2 (6-12 months) and T3 (12-24 months). Statistical analysis was performed using the independent T test, Mann-Whitney test and Fisher's exact test at a significance level of 0.05.

RESULTS

The success rate of each stage in both groups was 100%. Through quantitative comparison of radiographic outcomes, there was no statistically significant difference between the two groups in terms of root development and periapical lesion healing at each stage, except that the increase rate of radiographic root area in PRF group in the T3 stage was above one in CGF group with statistically significance.

CONCLUSIONS

Both CGF and PRF had a similar clinical performance regarding resolution of clinical signs and symptoms, periapical lesion healing, and continued root development as scaffolds in RET. Further prospective studies with large samples for longer follow-up periods are needed.

Stem cell-derived exosomes for dentin-pulp complex regeneration: a mini-review

This mini-review was conducted to present an overview of the use of exosomes in regenerating the dentin-pulp complex (DPC). The PubMed and Scopus databases were searched for relevant articles published between January 1, 2013 and January 1, 2023. The findings of basic in vitro studies indicated that exosomes enhance the proliferation and migration of mesenchymal cells, as human dental pulp stem cells, via mitogen-activated protein kinases and Wingless-Int signaling pathways. In addition, they possess proangiogenic potential and contribute to neovascularization and capillary tube formation by promoting endothelial cell proliferation and migration of human umbilical vein endothelial cells. Likewise, they regulate the migration and differentiation of Schwann cells, facilitate the conversion of M1 pro-inflammatory macrophages to M2 anti-inflammatory phenotypes, and mediate immune suppression as they promote regulatory T cell conversion. Basic in vivo studies have indicated that exosomes triggered the regeneration of dentin-pulp-like tissue, and exosomes isolated under odontogenic circumstances are particularly strong inducers of tissue regeneration and stem cell differentiation. Exosomes are a promising regenerative tool for DPC in cases of small pulp exposure or for whole-pulp tissue regeneration.

Polymeric Scaffolds Used in Dental Pulp Regeneration by Tissue Engineering Approach

Currently, the challenge in dentistry is to revitalize dental pulp by utilizing tissue engineering technology; thus, a biomaterial is needed to facilitate the process. One of the three essential elements in tissue engineering technology is a scaffold. A scaffold acts as a three-dimensional (3D) framework that provides structural and biological support and creates a good environment for cell activation, communication between cells, and inducing cell organization. Therefore, the selection of a scaffold represents a challenge in regenerative endodontics. A scaffold must be safe, biodegradable, and biocompatible, with low immunogenicity, and must be able to support cell growth. Moreover, it must be supported by adequate scaffold characteristics, which include the level of porosity, pore size, and interconnectivity; these factors ultimately play an essential role in cell behavior and tissue formation. The use of natural or synthetic polymer scaffolds with excellent mechanical properties, such as small pore size and a high surface-to-volume ratio, as a matrix in dental tissue engineering has recently received a lot of attention because it shows great potential with good biological characteristics for cell regeneration. This review describes the latest developments regarding the usage of natural or synthetic scaffold polymers that have the ideal biomaterial properties to facilitate tissue regeneration when combined with stem cells and growth factors in revitalizing dental pulp tissue. The utilization of polymer scaffolds in tissue engineering can help the pulp tissue regeneration process.

Chitosan/Xanthan/Hydroxyapatite-graphene oxide porous scaffold associated with mesenchymal stem cells for dentin-pulp complex regeneration

The aim of this paper was to synthesize and characterize polymeric scaffolds of Chitosan/Xanthan/Hydroxyapatite-Graphene Oxide nanocomposite associated with mesenchymal stem cells for regenerative dentistry application. The chitosan-xanthan gum (CX) complex was associated with Hydroxyapatite-Graphene Oxide (HA-GO) nanocomposite with different Graphene Oxides (GO) concentration (0.5 wt%; 1.0 wt%; 1.5 wt%). The scaffolds characterizations were performed by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Raman spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and contact angle. The mechanical properties were assessed by compressive strength. The in vitro bioactivity and the in vitro cytotoxicity test (MTT test) were analyzed as well. The data was submitted to the Normality and Homogeneity tests. In vitro Indirect Cytotoxicity assay data was statistically analyzed by ANOVA two-way, followed by Tukey's test (α = 0.05). Compressive strength and contact angle data were statistically analyzed by one-way ANOVA, followed by Tukey's test (α = 0.05). XRD showed the presence of Hydroxyapatite (HA) peaks in the structures CXHA, CXHAGO 0.5%,1.0% and 1.5%. FT-IR showed amino and carboxylic bands characteristic of CX. Raman spectroscopy analysis evidenced a high quality of the GO. In the TGA it was observed the mass loss associated with the CX degradation by depolymerization. SEM analysis showed pores in the scaffolds, in addition to HA incorporated and adhered to the polymer. Contact angle test showed that scaffolds have a hydrophilic characteristic, with the CX group the highest contact angle and CXHA the lowest (p < 0.05). 1.0 wt% GO significantly increased the compressive strength compared to other compositions. In the bioactivity test, the apatite crystals precipitation on the scaffold surface was observed. MTT test showed high cell viability in CXHAGO 1.0% and CXHAGO 1.5% scaffold. CXHAGO scaffolds are promising for regenerative dentistry application because they have morphological characteristics, mechanical and biological properties favorable for the regeneration process.

Characterization of a bioscaffold containing polysaccharide acemannan and native collagen for pulp tissue regeneration

Dental pulp regeneration exploits tissue engineering concepts using stem cells/scaffolds/growth-factors. Extracted collagen is commonly used as a biomaterial-scaffold due to its biocompatibility/biodegradability and mimics the natural extracellular matrix. Adding biomolecules into a collagen-scaffold enhanced pulp regeneration. Acemannan, β-(1-4)-acetylated-polymannose, is a polysaccharide extracted from aloe vera. Acemannan is a regenerative biomaterial. Therefore, acemannan could be a biomolecule in a collagen-scaffold. Here, acemannan and native collagen were obtained and characterized. The AceCol-scaffold's physical properties were investigated using FTIR, SEM, contact angle, swelling, pore size, porosity, compressive modulus, and degradation assays. The AceCol-scaffold's biocompatibility, growth factor secretion, osteogenic protein expression, and calcification were evaluated in vitro. The AceCol-scaffolds demonstrated higher hydrophilicity, swelling, porosity, and larger pore size than the collagen scaffolds (p < 0.05). Better cell-cell and cell-scaffold adhesion, and dentin extracellular matrix protein (BSP/OPN/DSPP) expression were observed in the AceCol-scaffold, however, DSPP expression was not detected in the collagen group. Significantly increased cellular proliferation, VEGF and BMP2 expression, and mineralization were detected in the AceCol-scaffold compared with the collagen-scaffold (p < 0.05). Computer simulation revealed that acemannan's 3D structure changes to bind with collagen. In conclusion, the AceCol-scaffold synergistically provides better physical and biological properties than collagen. The AceCol-scaffold is a promising material for tissue regeneration.

Multifunctional sponge scaffold loaded with concentrated growth factors for promoting wound healing

Although both are applied in regenerative medicine, acellular dermal matrix (ADM) and concentrated growth factor (CGF) have their respective shortcoming: The functioning of CGF is often hindered by sudden release effects, among other problems, and ADM can only be used in outer dressing for wound healing. In this study, a compound network with physical-chemical double cross-linking was constructed using chemical cross-linking and the intertwining of ADM and chitosan chains under freezing conditions; equipped with good biocompatibility and cell/tissue affinity, the heparin-modified composite scaffold was able to significantly promote cell adhesion and proliferation to achieve adequate fixation and slow down the release of CGF; polydopamine nanoparticles having excellent near-infrared light photothermal conversion ability could significantly promote the survival of rat autologous skin grafts. In a word, this multifunctional composite scaffold is a promising new type of implant biomaterial capable of delivering CGF to promote the healing of full-thickness skin defects.

Concentrated Growth Factors Combined with Lipopolysaccharide Stimulate the In Vitro Regenerative and Osteogenic Activities of Human Dental Pulp Stem Cells by Balancing Inflammation

Aim

We investigated the long-term effects of exposure to concentrated growth factors (CGFs) on the regenerative properties of dental pulp stem cells (DPSCs) in the presence and absence of lipopolysaccharide (LPS) as a proinflammatory agent.

Methods

DPSCs were cultured with CGF at different concentrations of LPS (0.1, 1, and 10 µg/ml) for 21 days. Then, using MTT and scratch assays, the cell viability and migration were examined. Osteogenic stimulation was evaluated by alkaline phosphatase (ALP) staining and Sirius Red staining, which determined the ALP activity and collagen levels, respectively. The expression levels of osteogenic markers were quantified using the qRT-PCR method. One-way analysis of variance (ANOVA) and Tukey's HSD test were used to analyze differences between groups.

Results

Long-term treatment of DPSCs with CGFs reduced LPS-induced cell death. Moreover, CGF and LPS (1 µg/ml), either in combination or alone, improved the DPSC migratory ability and caused a significant increase in osteogenic stimulation through the upregulation of collagen levels and ALP activity. Additionally, CGFs significantly upregulated RUNX2, DSPP, OCN, and OPN mRNA levels (as osteogenic markers), while LPS (1 µg/ml) only significantly increased OCN overexpression.

Conclusion

Our findings are evidence that CGF could be a promising agent to induce dentin-pulp complex healing in long-term chronic inflammation.

Comparative Evaluation of Platelet-rich Fibrin and Concentrated Growth Factor as Scaffolds in Regenerative Endodontic Procedure: A Randomized Controlled Clinical Trial

AIM

This randomized controlled trial evaluated the efficacy of platelet-rich fibrin (PRF) and concentrated growth factor (CGF) as scaffolds in the regenerative endodontic procedure (REP) using clinical and radiographic parameters along with cone-beam computed tomographic (CBCT) analysis.

MATERIALS AND METHODS

The apexogenesis procedure was performed in 16 teeth. They were randomly divided into two groups of eight teeth each: group I and group II. In group I PRF was used as the scaffold and in group II CGF was used as the scaffold. They were evaluated for pain, pulpal vitality, tenderness on percussion, and mobility, and also evaluated using digital radiographs at 3, 6, 12, and 18 months interval. The response of the teeth was graded using Chen and Chen criteria. Increase in root length, reduction in the apical foramen dimension, and reduction in periapical lesion volume were evaluated using CBCT scans taken preoperatively and at 18 months.

RESULTS

At the end of 3 months, 50% of teeth without periapical pathology were found to be vital in both groups. At the end of 18 months, 60% of the teeth in both groups showed increase in root length, all teeth showed closure of apical foramen, and reduction in the volume of periapical lesion. However, there was no statistically significant difference between the groups (p < 0.05).

CONCLUSION

The clinical and radiographic features reported in this study revealed that both PRF and CGF act as effective scaffolds in REP for regeneration of pulp-dentin complex with promising results.

CLINICAL SIGNIFICANCE

Apexogenesis by revascularization has not been used regularly for the treatment of nonvital teeth with open apex because the results are not reliable. Since platelet concentrates like PRF and CGF are rich in growth factors; when apexogenesis is performed by REP using these platelet concentrates, desirable results can be achieved in a short duration of time. They also accelerate the healing of periapical lesions present in such cases. With the increased success rate of apexogenesis with REP, many clinicians would prefer to use REPs as a treatment option for teeth with open apex.

Thermosensitive hydrogel loaded with concentrated growth factors promote bone repair in segmental bone defects

Treating critical-size bone defects beyond the body’s self-healing capacity is a challenging clinical task. In this study, we investigate the effect of concentrate growth factors (CGFs) loaded Poloxamer 407 hydrogel on the viability and osteogenic differentiation potential of bone marrow mesenchymal stem cells (BMSCs) and reconstruction of critical-size bone defects. In vitro, this CGFs-loaded thermosensitive hydrogel can significantly promote proliferation, maintain cell viability, and induce osteogenic differentiation of BMSCs by up-regulating the mineralization and alkaline phosphatase (ALP) activity, as well as gene markers, including runt-related transcription factor-2 (Runx-2), type I collagen (Col-1), osteocalcin (OCN), as well as osteopontin (OPN). In vivo, Micro-CT radiography analysis and histological detection demonstrated that the CGFs-loaded hydrogel significantly induced bone healing and reconstructed the medullary cavity structure in critical-size bone defect models. In conclusion, this strategy of transplantation of CGFs-loaded hydrogel promoted bone regeneration and prevented bone nonunion, so as to provide basis for clinical treatment for repairing critical-size bone defects.

The Regenerative Potential of Decellularized Dental Pulp Extracellular Matrix: A Systematic Review

INTRODUCTION

The regeneration of dental pulp remains a challenge. Although several treatment modalities have been proposed to promote pulpal regeneration, these treatments have several drawbacks. More recently, decellularized dental pulp extracellular matrix (DP-ECM) has been proposed to regenerate dental pulp. However, to date, no systematic review has summarized the overall outcome and assessed the available literature focusing on the endodontic use of DP-ECM. The aim of this systematic review is to critically appraise the literature, summarize the overall outcomes, and provide clinical recommendations about DP-ECM.

METHODOLOGY

Following the Participants Intervention Control and Outcomes (PICO) principle, a focused question was constructed before conducting a search of the literature and of electronic research databases and registers. The focused question was: 'Compared to controls, does decellularized dental pulp extracellular matrix (DP-ECM) stimulate the regeneration of dental pulp cells and tissue?' Quality assessment of the studies was carried out using Guidelines for Reporting Pre-Clinical in Vitro Studies on Dental Materials and ARRIVE guidelines.

RESULTS

12 studies were included in this review. Data from five in vitro experiments and eight in vivo experiments were extracted and the quality of the experiments was assessed. In majority of the studies, DP-ECM appeared to have stimulated pulpal regeneration. However, several sources of bias and methodological deficiencies were found during the quality assessment.

CONCLUSION

Within the limitations of this review and the included studies, it may be concluded that there is insufficient evidence to deduce the overall efficacy of DP-ECM for pulpal regeneration. More research, clinical and pre-clinical, is required for more conclusive evidence.

Cells and material-based strategies for regenerative endodontics

The carious process leads to inflammation of pulp tissue. Current care options include root canal treatment or apexification. These procedures, however, result in the loss of tooth vitality, sensitivity, and healing. Pulp capping and dental pulp regeneration are continually evolving techniques to regenerate pulp tissue, avoiding necrosis and loss of vitality. Many studies have successfully employed stem/progenitor cell populations, revascularization approaches, scaffolds or material-based strategies for pulp regeneration. Here we outline advantages and disadvantages of different methods and techniques which are currently being used in the field of regenerative endodontics. We also summarize recent findings on efficacious peptide-based materials which target the dental niche.

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Mechanisms of bone remodeling and therapeutic strategies in chronic apical periodontitis

Chronic periapical periodontitis (CAP) is a typical oral disease in which periodontal inflammation caused by an odontogenic infection eventually leads to bone loss. Uncontrolled infections often lead to extensive bone loss around the root tip, which ultimately leads to tooth loss. The main clinical issue in the treatment of periapical periodontitis is the repair of jawbone defects, and infection control is the first priority. However, the oral cavity is an open environment, and the distribution of microorganisms through the mouth in jawbone defects is inevitable. The subversion of host cell metabolism by oral microorganisms initiates disease. The presence of microorganisms stimulates a series of immune responses, which in turn stimulates bone healing. Given the above background, we intended to examine the paradoxes and connections between microorganisms and jaw defect repair in anticipation of new ideas for jaw defect repair. To this end, we reviewed the microbial factors, human signaling pathways, immune cells, and cytokines involved in the development of CAP, as well as concentrated growth factor (CGF) and stem cells in bone defect repair, with the aim of understanding the impact of microbial factors on host cell metabolism to inform the etiology and clinical management of CAP.

Investigating the Effects of Conditioned Media from Stem Cells of Human Exfoliated Deciduous Teeth on Dental Pulp Stem Cells

Pulp regeneration has recently attracted interest in modern dentistry. However, the success ratio of pulp regeneration is low due to the compromising potential of stem cells, such as their survival, migration, and odontoblastic differentiation. Stem cells from human exfoliated deciduous teeth (SHED) have been considered a promising tool for regenerative therapy due to their ability to secrete multiple factors that are essential for tissue regeneration, which is achieved by minimally invasive procedures with fewer ethical or legal concerns than those of other procedures. The aim of this study is to investigate the potency of SHED-derived conditioned media (SHED CM) on dental pulp stem cells (DPSCs), a major type of mesenchymal stem cells for dental pulp regeneration. Our results show the promotive efficiency of SHED CM on the proliferation, survival rate, and migration of DPSCs in a dose-dependent manner. Upregulation of odontoblast/osteogenic-related marker genes, such as ALP, DSPP, DMP1, OCN, and RUNX2, and enhanced mineral deposition of impaired DPSCs are also observed in the presence of SHED CM. The analysis of SHED CM found that a variety of cytokines and growth factors have positive effects on cell proliferation, migration, anti-apoptosis, and odontoblast/osteogenic differentiation. These findings suggest that SHED CM could provide some benefits to DPSCs in pulp regeneration.

Plasma Rich in Growth Factors in the Treatment of Endodontic Periapical Lesions in Adult Patients: A Narrative Review

Platelet concentrates have been widely used in regenerative medicine, including endodontics. The aim of this manuscript was to assess critically the efficacy of PRF in the treatment of endodontic periapical lesions in adult patients on the basis of the literature. The PICO approach was used to properly develop literature search strategies. The PubMed database was analyzed with the keywords: "((PRP) OR (PRF) OR (PRGF) OR (CGF)) AND (endodontic) AND ((treatment) OR (therapy))". After screening of 155 results, 14 articles were included in this review. Different types of platelet concentrates are able to stimulate the processes of proliferation and differentiation of mesenchymal stem cells. Platelet rich fibrin (PRF) releases growth factors for at least 7 days at the application site. Growth factors and released cytokines stimulate the activity of osteoblasts. Moreover, the release of growth factors accelerates tissue regeneration by increasing the migration of fibroblasts. It was not possible to assess the efficacy of PRF supplementation in the treatment of endodontic periapical lesions in permanent, mature teeth with closed apexes, due to the lack of well-designed scientific research. Further studies are needed to analyze the effect of PRF on the healing processes in the periapical region.

Dentin-Pulp Complex Tissue Regeneration via Three-Dimensional Cell Sheet Layering

The dentin-pulp complex is a unique structure in teeth that contains both hard and soft tissues. Generally, deep caries and trauma cause damage to the dentin-pulp complex, and if left untreated, this damage will progress to irreversible pulpitis. The aim of this study was to fabricate a layered cell sheet composed of rat dental pulp (DP) cells and odontogenic differentiation of pulp (OD) cells and to investigate the ability to regenerate the dentin-pulp complex in a scaffold tooth. We fabricated two single cell sheets composed of DP cells (DP cell sheet) or OD cells (OD cell sheet) and a layered cell sheet made by layering both cells. The characteristics of the fabricated cell sheets were analyzed using light microscopy, scanning electron microscope (SEM), hematoxylin-eosin (HE) staining, and immunohistochemistry (IHC). Furthermore, the cell sheets were transplanted into the subrenal capsule of immunocompromised mice for 8 weeks. After this, the regenerative capacity to form dentin-like tissue was evaluated using micro-computed tomography (micro-CT), HE staining, and IHC. The findings of SEM and IHC confirmed that layered cell sheets fabricated by stacking OD cells and DP cells maintained their cytological characteristics. Micro-CT of layered cell sheet transplants revealed a mineralized capping of the access cavity in the crown area, similar to that of natural dentin. In contrast, the OD cell sheet group demonstrated the formation of irregular fragments of mineralized tissue in the pulp cavity, and the DP cell sheet did not develop any hard tissue. Moreover, bone volume/tissue volume (BV/TV) showed a significant increase in hard tissue formation in the layered cell sheet group compared with that in the single cell sheet group (p < 0.05). HE staining also showed a combination of soft and hard tissue formation in the layered cell sheet group. Furthermore, IHC confirmed that the dentin-like tissue generated from the layered cell sheet expressed characteristic markers of dentin but not bone equivalent to that of a natural tooth. In conclusion, this study demonstrates the feasibility of regenerating dentin-pulp complex using a bioengineered tissue designed to simulate the anatomical structure. Impact statement The dentin-pulp complex can be destroyed by deep caries and trauma, which may cause pulpitis and progress to irreversible pulpitis, apical periodontitis, and even tooth loss. Current treatments cannot maintain pulp health, and teeth can become brittle. We developed a three-dimensional (3D) layered cell sheet using dental pulp cells and odontogenic differentiation of pulp cells for dentin-pulp complex regeneration. Our layered cell sheet enables the regeneration of an organized 3D dentin-pulp-like structure comparable with that of natural teeth. This layered cell sheet technology may contribute to dentin-pulp complex regeneration and provide a novel method for complex tissue engineering.