Autologous dental pulp stem cells in regeneration of defect created in canine periodontal tissue

Application of mesenchymal stem/stromal cells in periodontal regeneration: Opportunities and challenges

Guided tissue regeneration (GTR) has been widely used in the periodontal treatment of intrabony and furcation defects for nearly four decades. The treatment outcomes have shown effectiveness in reducing pocket depth, improving attachment gain and bone filling in periodontal tissue. Although applying GTR could reconstruct the periodontal tissue, the surgical indications are relatively narrow, and some complications and race ethic problems bring new challenges. Therefore, it is challenging to achieve a consensus concerning the clinical benefits of GTR. With the appearance of stem cell-based regenerative medicine, mesenchymal stem/stromal cells (MSCs) have been considered a promising cell resource for periodontal regeneration. In this review, we highlight preclinical and clinical periodontal regeneration using MSCs derived from distinct origins, including non-odontogenic and odontogenic tissues and induced pluripotent stem cells, and discuss the transplantation procedures, therapeutic mechanisms, and concerns to evaluate the effectiveness of MSCs.

Stem cells in regenerative dentistry: Current understanding and future directions

BACKGROUND

Regenerative dentistry aims to enhance the structure and function of oral tissues and organs. Modern tissue engineering harnesses cell and gene-based therapies to advance traditional treatment approaches. Studies have demonstrated the potential of mesenchymal stem cells (MSCs) in regenerative dentistry, with some progressing to clinical trials. This review comprehensively examines animal studies that have utilized MSCs for various therapeutic applications. Additionally, it seeks to bridge the gap between related findings and the practical implementation of MSC therapies, offering insights into the challenges and translational aspects involved in transitioning from preclinical research to clinical applications.

HIGHLIGHTS

To achieve this objective, we have focused on the protocols and achievements related to pulp-dentin, alveolar bone, and periodontal regeneration using dental-derived MSCs in both animal and clinical studies. Various types of MSCs, including dental-derived cells, bone-marrow stem cells, and umbilical cord stem cells, have been employed in root canals, periodontal defects, socket preservation, and sinus lift procedures. Results of such include significant hard tissue reconstruction, functional pulp regeneration, root elongation, periodontal ligament formation, and cementum deposition. However, cell-based treatments for tooth and periodontium regeneration are still in early stages. The increasing demand for stem cell therapies in personalized medicine underscores the need for scientists and responsible organizations to develop standardized treatment protocols that adhere to good manufacturing practices, ensuring high reproducibility, safety, and cost-efficiency.

CONCLUSION

Cell therapy in regenerative dentistry represents a growing industry with substantial benefits and unique challenges as it strives to establish sustainable, long-term, and effective oral tissue regeneration solutions.

Trends of regenerative tissue engineering for oral and maxillofacial reconstruction in veterinary medicine

Oral and maxillofacial (OMF) defects are not limited to humans and are often encountered in other species. Reconstructing significant tissue defects requires an excellent strategy for efficient and cost-effective treatment. In this regard, tissue engineering comprising stem cells, scaffolds, and signaling molecules is emerging as an innovative approach to treating OMF defects in veterinary patients. This review presents a comprehensive overview of OMF defects and tissue engineering principles to establish proper treatment and achieve both hard and soft tissue regeneration in veterinary practice. Moreover, bench-to-bedside future opportunities and challenges of tissue engineering usage are also addressed in this literature review.

Bioactive Scaffolds as a Promising Alternative for Enhancing Critical-Size Bone Defect Regeneration in the Craniomaxillofacial Region

Reconstruction of critical-size bone defects (CSDs) in the craniomaxillofacial (CMF) region remains challenging. Scaffold-based bone-engineered constructs have been proposed as an alternative to the classical treatments made with autografts and allografts. Scaffolds, a key component of engineered constructs, have been traditionally viewed as biologically passive temporary replacements of deficient bone lacking intrinsic cues to promote osteogenesis. Nowadays, scaffolds are functionalized, giving rise to bioactive scaffolds promoting bone regeneration more effectively than conventional counterparts. This review focuses on the three approaches most used to bioactivate scaffolds: (1) conferring microarchitectural designs or surface nanotopography; (2) loading bioactive molecules; and (3) seeding stem cells on scaffolds, providing relevant examples of in vivo (preclinical and clinical) studies where these methods are employed to enhance CSDs healing in the CMF region. From these, adding bioactive molecules (specifically bone morphogenetic proteins or BMPs) to scaffolds has been the most explored to bioactivate scaffolds. Nevertheless, the downsides of grafting BMP-loaded scaffolds in patients have limited its successful translation into clinics. Despite these drawbacks, scaffolds containing safer, cheaper, and more effective bioactive molecules, combined with stem cells and topographical cues, remain a promising alternative for clinical use to treat CSDs in the CMF complex replacing autografts and allografts.

Advances Focusing on the Application of Decellularized Extracellular Matrix in Periodontal Regeneration

The decellularized extracellular matrix (dECM) is capable of promoting stem cell proliferation, migration, adhesion, and differentiation. It is a promising biomaterial for application and clinical translation in the field of periodontal tissue engineering as it most effectively preserves the complex array of ECM components as they are in native tissue, providing ideal cues for regeneration and repair of damaged periodontal tissue. dECMs of different origins have different advantages and characteristics in promoting the regeneration of periodontal tissue. dECM can be used directly or dissolved in liquid for better flowability. Multiple ways were developed to improve the mechanical strength of dECM, such as functionalized scaffolds with cells that harvest scaffold-supported dECM through decellularization or crosslinked soluble dECM that can form injectable hydrogels for periodontal tissue repair. dECM has found recent success in many periodontal regeneration and repair therapies. This review focuses on the repairing effect of dECM in periodontal tissue engineering, with variations in cell/tissue sources, and specifically discusses the future trend of periodontal regeneration and the future role of soluble dECM in entire periodontal tissue regeneration.

Oral cavity-derived stem cells and preclinical models of jaw-bone defects for bone tissue engineering

BACKGROUND

Jaw-bone defects caused by various diseases lead to aesthetic and functional complications, which can seriously affect the life quality of patients. Current treatments cannot fully meet the needs of reconstruction of jaw-bone defects. Thus, the research and application of bone tissue engineering are a "hot topic." As seed cells for engineering of jaw-bone tissue, oral cavity-derived stem cells have been explored and used widely. Models of jaw-bone defect are excellent tools for the study of bone defect repair in vivo. Different types of bone defect repair require different stem cells and bone defect models. This review aimed to better understand the research status of oral and maxillofacial bone regeneration.

MAIN TEXT

Data were gathered from PubMed searches and references from relevant studies using the search phrases "bone" AND ("PDLSC" OR "DPSC" OR "SCAP" OR "GMSC" OR "SHED" OR "DFSC" OR "ABMSC" OR "TGPC"); ("jaw" OR "alveolar") AND "bone defect." We screened studies that focus on "bone formation of oral cavity-derived stem cells" and "jaw bone defect models," and reviewed the advantages and disadvantages of oral cavity-derived stem cells and preclinical model of jaw-bone defect models.

CONCLUSION

The type of cell and animal model should be selected according to the specific research purpose and disease type. This review can provide a foundation for the selection of oral cavity-derived stem cells and defect models in tissue engineering of the jaw bone.

The Role and Involvement of Stem Cells in Periodontology

Periodontitis is a widespread inflammatory condition, characterized by a progressive deterioration of the supporting structures of the teeth. Due to the complexity of periodontal tissue and the surrounding inflammatory microenvironment, the repair of lesions at this level represents a continuous challenge. The regeneration of periodontal tissues is considered a promising strategy. Stem cells have remarkable properties, such as immunomodulatory potential, proliferation, migration, and multilineage differentiation. Thus, they can be used to repair tissue damage and reduce inflammation, potentially leading to periodontal regeneration. Among the stem cells used for periodontal regeneration, we studied dental mesenchymal stem cells (DMSCs), non-dental stem cells, and induced pluripotent stem cells (IPSCs). Although these cells have well documented important physiological characteristics, their use in contemporary practice to repair the affected periodontium is still a challenge.

Regeneration of periodontal bone defects with mesenchymal stem cells in animal models. Systematic review and meta-analysis

The aim of this study was to evaluate the efficacy of mesenchymal stem cells (MSCs) in the regeneration of periodontal bone defects in animal models. A systematic review and meta-analysis were conducted following the PRISMA guidelines, and the study was recorded in PROSPERO under reference number CDR42021247462. The PICO question was: is periodontal regeneration (cementum, periodontal ligament and alveolar bone) with MSCs more effective than other techniques? Three groups were considered: Group 1: MSCs alone or mixed with regenerative materials. Group 2: only regenerative materials. Group 3: no regenerative material nor MSCs. The search was conducted using MeSH with a total of 18 articles for qualitative analysis and 5 for quantitative analysis. For the meta-analysis, a modification of the effect size algorithm was developed, which considered a comparison of means between treatments using the Student's t sample distribution. When comparing the effect size between Group 1 and Group 2, the effect size for the new cementum was 2.83 mm with an estimated confidence interval of 95% (CI 95%) between 0.48 and 5.17 mm. When considering the fit to a random-effects model, the combined variance (τ²) was 6.1573 mm, with a standard deviation (SD) of 5.6008 mm and a percentage of total heterogeneity I² of 92.33% (p < 0.0001). For new bone, the effect size was 0.88 mm, CI 95% - 0.25 to 2.01 mm, τ² = 1.3108 mm (SD = 1.2021 mm) and I² = 80.46%, p = 0.0004). With regard to the new periodontal ligament, it was not possible for the meta-analysis to be performed. MSCs have a greater capacity for tissue regeneration in root cementum than in alveolar bone compared to other regenerative materials.

Impact of Oral Mesenchymal Stem Cells Applications as a Promising Therapeutic Target in the Therapy of Periodontal Disease

Periodontal disease is a chronic inflammatory condition affecting about 20–50% of people, worldwide, and manifesting clinically through the detection of gingival inflammation, clinical attachment loss, radiographically assessed resorption of alveolar bone, gingival bleeding upon probing, teeth mobility and their potential loss at advanced stages. It is characterized by a multifactorial etiology, including an imbalance of the oral microbiota, mechanical stress and systemic diseases such as diabetes mellitus. The current standard treatments for periodontitis include eliminating the microbial pathogens and applying biomaterials to treat the bone defects. However, periodontal tissue regeneration via a process consistent with the natural tissue formation process has not yet been achieved. Developmental biology studies state that periodontal tissue is composed of neural crest-derived ectomesenchyme. The aim of this review is to discuss the clinical utility of stem cells in periodontal regeneration by reviewing the relevant literature that assesses the periodontal-regenerative potential of stem cells.

Botanicals and Oral Stem Cell Mediated Regeneration: A Paradigm Shift from Artificial to Biological Replacement

Stem cells are a well-known autologous pluripotent cell source, having excellent potential to develop into specialized cells, such as brain, skin, and bone marrow cells. The oral cavity is reported to be a rich source of multiple types of oral stem cells, including the dental pulp, mucosal soft tissues, periodontal ligament, and apical papilla. Oral stem cells were useful for both the regeneration of soft tissue components in the dental pulp and mineralized structure regeneration, such as bone or dentin, and can be a viable substitute for traditionally used bone marrow stem cells. In recent years, several studies have reported that plant extracts or compounds promoted the proliferation, differentiation, and survival of different oral stem cells. This review is carried out by following the PRISMA guidelines and focusing mainly on the effects of bioactive compounds on oral stem cell-mediated dental, bone, and neural regeneration. It is observed that in recent years studies were mainly focused on the utilization of oral stem cell-mediated regeneration of bone or dental mesenchymal cells, however, the utility of bioactive compounds on oral stem cell-mediated regeneration requires additional assessment beyond in vitro and in vivo studies, and requires more randomized clinical trials and case studies.

Attachment and Osteogenic Potential of Dental Pulp Stem Cells on Non-Thermal Plasma and UV Light Treated Titanium, Zirconia and Modified PEEK Surfaces

Ultraviolet (UV) light and non-thermal plasma (NTP) treatment are chairside methods that can efficiently improve the biological aging of implant material surfaces caused by customary storage. However, the behaviors of stem cells on these treated surfaces of the implant are still unclear. This study aimed to investigate the effects of UV light and NTP treated surfaces of titanium, zirconia and modified polyetheretherketone (PEEK, BioHPP) on the attachment and osteogenic potential of human dental pulp stem cells (DPSCs) in vitro. Machined disks were treated using UV light and argon or oxygen NTP for 12 min each. Untreated disks were set as controls. DPSCs were cultured from the wisdom teeth of adults that gave informed consent. After 24 h of incubation, the attachment and viability of cells on surfaces were assessed. Cells were further osteogenically induced, alkaline phosphatase (ALP) activity was detected via a p-Nitrophenyl phosphate assay (day 14 and 21) and mineralization degree was measured using a Calcium Assay kit (day 21). UV light and NTP treated titanium, zirconia and BioHPP surfaces improved the early attachment and viability of DPSCs. ALP activity and mineralization degree of osteoinductive DPSCs were significantly increased on UV light and NTP treated surfaces of titanium, zirconia and also oxygen plasma treated Bio-HPP (p < 0.05). In conclusion, UV light and NTP treatments may improve the attachment of DPSCs on titanium, zirconia and BioHPP surfaces. Osteogenic differentiation of DPSCs can be enhanced on UV light and NTP treated surfaces of titanium and zirconia, as well as on oxygen plasma treated Bio-HPP.

Stem Cell Transplantation and Cell-Free Treatment for Periodontal Regeneration

Increasing attention has been paid to cell-based medicines. Many in vivo and in vitro studies have demonstrated the efficacy of stem cell transplantation for the regeneration of periodontal tissues over the past 20 years. Although positive evidence has accumulated regarding periodontal regeneration using stem cells, the exact mechanism of tissue regeneration is still largely unknown. This review outlines the practicality and emerging problems of stem cell transplantation therapy for periodontal regeneration. In addition, possible solutions to these problems and cell-free treatment are discussed.

A Review of Tissue Engineering for Periodontal Tissue Regeneration

Periodontal disease is one of the most common diagnoses in small animal veterinary medicine. This infectious disease of the periodontium is characterized by the inflammation and destruction of the supporting structures of teeth, including periodontal ligament, cementum, and alveolar bone. Traditional periodontal repair techniques make use of open flap debridement, application of graft materials, and membranes to prevent epithelial downgrowth and formation of a long junctional epithelium, which inhibits regeneration and true healing. These techniques have variable efficacy and are made more challenging in veterinary patients due to the cost of treatment for clients, need for anesthesia for surgery and reevaluation, and difficulty in performing necessary diligent home care to maintain oral health. Tissue engineering focuses on methods to regenerate the periodontal apparatus and not simply to repair the tissue, with the possibility of restoring normal physiological functions and health to a previously diseased site. This paper examines tissue engineering applications in periodontal disease by discussing experimental studies that focus on dogs and other animal species where it could potentially be applied in veterinary medicine. The main areas of focus of tissue engineering are discussed, including scaffolds, signaling molecules, stem cells, and gene therapy. To date, although outcomes can still be unpredictable, tissue engineering has been proven to successfully regenerate lost periodontal tissues and this new possibility for treating veterinary patients is discussed.

Therapeutic Potential of Dental Pulp Stem Cells According to Different Transplant Types

Stem cells are unspecialised cells capable of perpetual self-renewal, proliferation and differentiation into more specialised daughter cells. They are present in many tissues and organs, including the stomatognathic system. Recently, the great interest of scientists in obtaining stem cells from human teeth is due to their easy availability and a non-invasive procedure of collecting the material. Three key components are required for tissue regeneration: stem cells, appropriate scaffold material and growth factors. Depending on the source of the new tissue or organ, there are several types of transplants. In this review, the following division into four transplant types is applied due to genetic differences between the donor and the recipient: xenotransplantation, allotransplantation, autotransplantation and isotransplantation (however, due to the lack of research, type was not included). In vivo studies have shown that Dental Pulp Stem Cells (DPSCs)can form a dentin-pulp complex, nerves, adipose, bone, cartilage, skin, blood vessels and myocardium, which gives hope for their use in various biomedical areas, such as immunotherapy and regenerative therapy. This review presents the current in vivo research and advances to provide new biological insights and therapeutic possibilities of using DPSCs.

Pleiotropin enhances the osteo/dentinogenic differentiation potential of dental pulp stem cells

Purpose: Pleiotrophin (PTN) is a heparin-binding growth-associated molecule and expressed in ameloblasts and odontoblasts throughout tooth maturation. Our previous study has shown that PTN expressed more than 20-fold higher in dental tissue than dental stem cells. However, the role of PTN on proliferation and osteo/dentinogenesis of dental pulp stem cells (DPSCs) is unclear. The purpose of the present study was to investigate the role of PTN on the DPSCs' function.Methods: DPSCs were isolated from human third molars. Short hairpin RNAs (shRNAs) was used to knock down the PTN expression in DPSCs. Real-time RT-PCR, alizarin red staining, quantitative calcium analysis, in vivo transplantation and cell counting kit-8 (CCK8) assay were used to study the function of DPSCs. Possible mechanism was studied by RNA sequencing.Results: After PTN depletion, ALP activity and mineralization ability of DPSCs decreased. Expression of DMP-1 and BSP weakened. Proliferation of DPSCs at 48 h and 72 h was inhibited. Furthermore, 50 pg/mL PTN recombinant protein rescued the impaired osteo/dentinogenic differentiation potential and proliferation ability caused by PTN depletion. In addition, RNA sequencing showed 221 genes were downregulated and 233 genes upregulated in PTN depleted DPSCs. Several genes including BMP2 and IGFBP5 might be associated with PTN function on the DPSCs. P53 and the AMPK signaling pathways were involved. LncRNA analysis displayed 47 significantly upregulated lncRNA and 31 downregulated lncRNA comparing PTN depleted DPSCs with the control.Conclusion: Our research demonstrated that PTN has a positive role in maintaining DPSCs proliferation and osteo/dentinogenic differentiation potential.

Nanomaterials and Stem Cell Differentiation Potential: An Overview of Biological Aspects and Biomedical Efficacy

Nanoparticles (NPs) due to their medical applications are widely used. Accordingly, the use of mesenchymal stem cells is one of the most important alternatives in tissue engineering field. NPs play effective roles in stem cells proliferation and differentiation. The combination of NPs and tissue regeneration by stem cells has created new therapeutic approach towards humanity. Of note, the physicochemical properties of NPs determine their biological function. Interestingly, various mechanisms such as modulation of signaling pathways and generation of reactive oxygen species, are involved in NPs-induced cellular proliferation and differentiation. This review summarized the types of nanomaterials effective on stem cell differentiation, the physicochemical features, biomedical application of these materials and relationship between nanomaterials and environment.

Influence of Dental Pulp Harvesting Method on the Viability and Differentiation Capacity of Adult Dental Pulp-Derived Mesenchymal Stem Cells

Objective

To compare two pulp harvesting methods for stem cell expansion, namely, conservative pulpotomy and pulpectomy from exodontia.

Method

Ten freshly extracted sound third molars from five patients were selected. Five were used in the control group, where pulp harvesting was performed by exodontia and the remaining teeth were used in the test group, where the pulp was harvested by conservative pulpotomy (preserving the tooth). This was a split-mouth design study, where a third molar from one side was randomly allocated into the test group and the contralateral tooth in the control group. After pulp harvesting, the following evaluations were performed: cell morphology, sterility test, immunophenotyping, differentiation assays, first pass live cell counts, time to cryopreservation, and total number of expanded cells at the end of the fourth pass.

Results

Regarding morphology, the cells from both groups presented a fibroblastic phenotype. All samples were sterile. Immunophenotyping demonstrated a positive expression for CD105, CD90, and CD73 and negative expression for CD45 in both groups. Differentiation assays were positive for osteogenic and chondrogenic differentiation in both groups. Regarding live cell counts in the first passage, the control group had 95.8% live cells in the total count and the test group 91.2% (p < 0.05). The time required for cryopreservation was equivalent in both groups 51.6 days and 52.6 days, respectively (p > 0.05). The total number of cells at the end of the fourth passage was 5,286,782 and 5,736,862, respectively (p > 0.05).

Conclusion

These results suggest that adult stem cell harvesting from conservative pulpotomy is as effective as the traditional exodontia-based method.

Therapeutic applications of dental pulp stem cells in regenerating dental, periodontal and oral-related structures

Dental pulp stem cells (DPSCs) have emerged as a promising tool with great potential for use in tissue regeneration and engineering. Some of the main advantages of these cells are their multifaceted differentiation capacity, along with their high proliferation rate, a relative simplicity of extraction and culture that enables obtaining patient-specific cell lines for their use in autologous cell therapy. PubMed, Scopus and Google Scholar databases were searched for relevant articles related to the use of DPSCs in regeneration of dentin-pulp complex (DPC), periodontal tissues, salivary gland and craniomaxillofacial bone defects. Few studies were found regarding the use of DPSCs for regeneration of DPC. Scaffold-based combined with DPSCs isolated from healthy pulps was the strategy used for DPC regeneration. Studies involved subcutaneous implantation of scaffolds loaded with DPSCs pretreated with odontogenic media, or performed on human tooth root model as a root slice. Most of the studies were related to periodontal tissue regeneration which mainly utilized DPSCs/secretome. For periodontal tissues, DPSCs or their secretome were isolated from healthy or inflamed pulps and they were used either for preclinical or clinical studies. Regarding salivary gland regeneration, the submandibular gland was the only model used for the preclinical studies and DPSCs or their secretome were isolated only from healthy pulps and they were used in preclinical studies. Likewise, DPSCs have been studied for craniomaxillofacial bone defects in the form of mandibular, calvarial and craniofacial bone defects where DPSCs were isolated only from healthy pulps for preclinical and clinical studies. From the previous results, we can conclude that DPSCs is promising candidate for dental and oral tissue regeneration.

Angiogenesis in Regenerative Dentistry: Are We Far Enough for Therapy?

Angiogenesis is a broad spread term of high interest in regenerative medicine and tissue engineering including the dental field. In the last two decades, researchers worldwide struggled to find the best ways to accelerate healing, stimulate soft, and hard tissue remodeling. Stem cells, growth factors, pathways, signals, receptors, genetics are just a few words that describe this area in medicine. Dental implants, bone and soft tissue regeneration using autologous grafts, or xenografts, allografts, their integration and acceptance rely on their material properties. However, the host response, through its vascularization, plays a significant role. The present paper aims to analyze and organize the latest information about the available dental stem cells, the types of growth factors with pro-angiogenic effect and the possible therapeutic effect of enhanced angiogenesis in regenerative dentistry.

Synthetic Scaffold/Dental Pulp Stem Cell (DPSC) Tissue Engineering Constructs for Bone Defect Treatment: An Animal Studies Literature Review

Background: Recently a greater interest in tissue engineering for the treatment of large bone defect has been reported. The aim of the present systematic review and meta-analysis was to investigate the effectiveness of dental pulp stem cells and synthetic block complexes for bone defect treatment in preclinical in vivo articles. Methods: The electronic database and manual search was conducted on Pubmed, Scopus, and EMBASE. The papers identified were submitted for risk-of-bias assessment and classified according to new bone formation, bone graft characteristics, dental pulp stem cells (DPSCs) culture passages and amount of experimental data. The meta-analysis assessment was conducted to assess new bone formation in test sites with DPSCs/synthetic blocks vs. synthetic block alone. Results: The database search identified a total of 348 papers. After the initial screening, 30 studies were included, according to the different animal models: 19 papers on rats, 3 articles on rabbits, 2 manuscripts on sheep and 4 papers on swine. The meta-analysis evaluation showed a significantly increase in new bone formation in favor of DPSCs/synthetic scaffold complexes, if compared to the control at 4 weeks (Mean Diff: 17.09%, 95% CI: 15.16–18.91%, p < 0.01) and at 8 weeks (Mean Diff: 14.86%, 95% CI: 1.82–27.91%, p < 0.01) in rats calvaria bone defects. Conclusion: The synthetic scaffolds in association of DPSCs used for the treatment of bone defects showed encouraging results of early new bone formation in preclinical animal studies and could represent a useful resource for regenerative bone augmentation procedures

Stem cell therapies for periodontal tissue regeneration: a network meta-analysis of preclinical studies

Background

Periodontal tissue regeneration (PTR) is the ultimate goal of periodontal therapy. Currently, stem cell therapy is considered a promising strategy for achieving PTR. However, there is still no conclusive comparison that distinguishes clear hierarchies among different kinds of stem cells.

Methods

A systematic review and network meta-analysis (NMA) was performed using MEDLINE (via PubMed), EMBASE, and Web of Science up to February 2020. Preclinical studies assessing five types of stem cells for PTR were included; the five types of stem cells included periodontal ligament-derived stem cells (PDLSCs), bone marrow-derived stem cells (BMSCs), adipose tissue-derived stem cells (ADSCs), dental pulp-derived stem cells (DPSCs), and gingival-derived stem cells (GMSCs). The primary outcomes were three histological indicators with continuous variables: newly formed alveolar bone (NB), newly formed cementum (NC), and newly formed periodontal ligament (NPDL). We performed pairwise meta-analyses using a random-effects model and then performed a random-effects NMA using a multivariate meta-analysis model.

Results

Sixty preclinical studies assessing five different stem cell-based therapies were identified. The NMA showed that in terms of NB, PDLSCs (standardized mean difference 1.87, 95% credible interval 1.24 to 2.51), BMSCs (1.88, 1.17 to 2.59), and DPSCs (1.69, 0.64 to 2.75) were statistically more efficacious than cell carriers (CCs). In addition, PDLSCs were superior to GMSCs (1.49, 0.04 to 2.94). For NC, PDLSCs (2.18, 1.48 to 2.87), BMSCs (2.11, 1.28 to 2.94), and ADSCs (1.55, 0.18 to 2.91) were superior to CCs. For NPDL, PDLSCs (1.69, 0.92 to 2.47) and BMSCs (1.41, 0.56 to 2.26) were more efficacious than CCs, and PDLSCs (1.26, 0.11 to 2.42) were superior to GMSCs. The results of treatment hierarchies also demonstrated that the two highest-ranked interventions were PDLSCs and BMSCs.

Conclusion

PDLSCs and BMSCs were the most effective and well-documented stem cells for PTR among the five kinds of stem cells evaluated in this study, and there was no statistical significance between them. To translate the stem cell therapies for PTR successfully in the clinic, future studies should utilize robust experimental designs and reports.

Regenerative Capacity of Dental Pulp Stem Cells: A Systematic Review

OBJECTIVES

The dental pulp contains undifferentiated mesenchymal cells, blood vessels and so on, which are responsible for routine functions of a tooth. The determination of stemness and regenerative properties using biomarkers and further application in routine practice may unravel its potential.

MATERIALS AND METHODS

Inclusion criteria-original research articles published in English, from 2000 to 2019, were collected both manually and by electronic search from databases of Cochrane, Medline, Embase, and PubMed. Exclusion criteria-articles other than English and review manuscripts were omitted. The shortlisted articles were reviewed for specific biomarkers, to assess the regenerative potential, stemness, and lineage of dental pulp stem cells.

RESULTS

Of 512 articles, 64 were selected and reviewed to determine the mesenchymal, neurogenic, vasculogenic, hematopoietic, and stem cell potential. On the basis of the search analysis, a panel of markers was proposed.

CONCLUSION

The application of proposed markers, on a pulpectomized tissue derived from human teeth, may be helpful to determine the regenerative potential and the usefulness in regenerative medicine and tissue engineering.

Insight into the Role of Dental Pulp Stem Cells in Regenerative Therapy

Mesenchymal stem cells (MSCs) have the capacity for self-renewal and multilineage differentiation potential, and are considered a promising cell population for cell-based therapy and tissue regeneration. MSCs are isolated from various organs including dental pulp, which originates from cranial neural crest-derived ectomesenchyme. Recently, dental pulp stem cells (DPSCs) and stem cells from human exfoliated deciduous teeth (SHEDs) have been isolated from dental pulp tissue of adult permanent teeth and deciduous teeth, respectively. Because of their MSC-like characteristics such as high growth capacity, multipotency, expression of MSC-related markers, and immunomodulatory effects, they are suggested to be an important cell source for tissue regeneration. Here, we review the features of these cells, their potential to regenerate damaged tissues, and the recently acquired understanding of their potential for clinical application in regenerative medicine.

Promising advances in clinical trials of dental tissue-derived cell-based regenerative medicine

Background

Advances in regenerative medicine with stem cells have led to clinical trials. Dental/oral tissues are emerging as promising cellular sources of human mesenchymal stem cells. Recently, dental tissue-derived cells have been used clinically due to their great potential, easy accessibility, and ability to be obtained via methods with low invasiveness. The aim of this study is to systematically assess the clinical effectiveness of dental cell-mediated therapies compared to current evidence-based methods in human patients.

Methods

The electronic databases MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov were searched up to December 2019 for clinical trials. Clinical trials with any intervention using stem cells/cells derived from dental tissue were included.

Results

A total of 815 studies were identified by the electronic search, and 38 articles qualified for full-text evaluation. Finally, 20 studies (10 clinical trials using dental pulp-derived cells, 3 clinical trials using periodontal ligament-derived cells, and 7 studies using gingiva-derived cells) were included in this review. No clinical trials using dental follicle- or apical papilla-derived cells were selected in this review. Dental pulp-derived cells were used in clinical trials for bone regeneration, periodontitis, and dental pulp regeneration. All clinical trials using periodontal ligament-derived cells and gingiva-derived cells were conducted for periodontal disease treatment and gingival augmentation, respectively. Among the 20 selected studies, 16 showed clinical benefits of cell transplantation therapies. In addition, no study reported adverse events that may have been associated with cell transplantation.

Conclusions

These findings indicate that dental tissue-derived cells would be useful for cell-based regenerative medicine for various diseases.

Mesenchymal stem cell-based tissue regeneration therapies for periodontitis

Periodontitis is commonly observed and is an important concern in dental health. It is characterized by a multifactorial etiology, including imbalance of oral microbiota, mechanical stress, and systemic diseases such as diabetes mellitus. The current standard treatments for periodontitis include elimination of the microbial pathogen and application of biomaterials for treating bone defects. However, the periodontal tissue regeneration via a process consistent with the natural tissue formation process has not yet been achieved. Developmental biology studies state that periodontal tissue is composed of neural crest-derived ectomesenchyme. To elucidate the process of periodontal regeneration, it is essential to understand the developmental background and intercellular cross-talk. Several recent studies have reported the efficacy of transplantation of mesenchymal stem cells for periodontal tissue regeneration. In this review, we discuss the basic knowledge of periodontal tissue regeneration using mesenchymal stem cells and highlight the potential of stem cell-based periodontal regenerative medicine.

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Neural crest cells regulate the development and homeostasis of periodontal tissues.

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Dental mesenchymal stem cells (MSCs) are used for treating alveolar bone defects.

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Non-odontogenic MSCs can be investigated for periodontal tissue regeneration.

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Using appropriate growth factors and scaffold may improve periodontium regeneration.

Mesenchymal stem cell-based bone tissue engineering for veterinary practice

Bone tissue engineering has been widely studied and proposed as a promising platform for correcting the bone defects. The applications of mesenchymal stem cell (MSC)-based bone tissue engineering have been investigated in various in vitro and in vivo models. In this regard, the promising animal bone defect models have been employed for illustrating the bone regenerative capacity of MSC-based bone tissue engineering. However, most studies aimed for clinical applications in human. These evidences suggest a knowledge gap to fulfill the accomplishment for veterinary implementation. In this review, the fundamental concept, knowledge, and technology of MSC-based bone tissue engineering focusing on veterinary applications are summarized. In addition, the potential canine MSCs resources for veterinary bone tissue engineering are reviewed, including canine bone marrow-derived MSCs, canine adipose-derived MSCs, and canine dental tissue-derived MSCs. This review will provide a basic and current information for studies aiming for the utilization of MSC-based bone tissue engineering in veterinary practice.

Periodontal regenerative medicine using mesenchymal stem cells and biomaterials: A systematic review of pre-clinical studies

The aim of the systematic review was to analyze the use of mesenchymal stem cells (MSC) and biomaterial for periodontal regeneration from preclinical animal models and human. Electronic databases were searched and additional hand-search in leading journals was performed. The research strategy was achieved according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The including criteria were as follows: MSC, biomaterial, in vivo studies, with histologic and radiologic analysis and written in English. The risk of bias was assessed for individual studies. A total of 50 articles were selected and investigated in the systematic review. These results indicate that MSC and scaffold provide beneficial effects on periodontal regeneration, with no adverse effects of such interventions. Future studies need to identify the suitable association of MSC and biomaterial and to characterize the type of new cementum and the organization of the periodontal ligament fiber regeneration.

Stem cell-based regenerative medicine

Recent developments in the stem cell biology provided new hopes in treatment of diseases and disorders that yet cannot be treated. Stem cells have the potential to differentiate into various cell types in the body during age. These provide new cells for the body as it grows, and replace specialized cells that are damaged. Since mesenchymal stem cells (MSCs) can be easily harvested from the adipose tissue and can also be cultured and expanded in vitro they have become a good target for tissue regeneration. These cells have been widespread used for cell transplantation in animals and also for clinical trials in humans. The purpose of this review is to provide a summary of our current knowledge regarding the important and types of isolated stem cells from different sources of animal models such as horse, pig, goat, dog, rabbit, cat, rat, mice etc. In this regard, due to the widespread use and lot of attention of MSCs, in this review, we will elaborate on use of MSCs in veterinary medicine as well as in regenerative medicine. Based on the studies in this field, MSCs found wide application in treatment of diseases, such as heart failure, wound healing, tooth regeneration etc.

Transplantation of dental pulp-derived cell sheets cultured on human amniotic membrane induced to differentiate into bone

OBJECTIVE

The usefulness of the amniotic membrane as a cell culture substrate has led to its use in the development of dental pulp-derived cell sheets. We induced osteoblastic differentiation of dental pulp-derived cell sheets and conducted histological and immunological examinations in addition to imaging assessments for regeneration of bone defects.

METHODS

Dental pulp cells were obtained by primary culture of the dental pulp tissue harvested from extracted wisdom teeth. These cells were maintained for three to four passages. Subsequently, the dental pulp cells were seeded onto an amniotic membrane to produce dental pulp-derived cell sheets. Following the induction of osteoblastic differentiation, the sheets were grafted into the subcutaneous tissue of the lower back and maxillary bone defect of a nude mouse. Histological and immunological examinations of both grafts were performed.

RESULTS

Dental pulp-derived cell sheets cultured on an osteoblast differentiation-inducing medium demonstrated resemblance to dental pulp tissue and produced calcified tissue. Mineralization was maintained following grafting of the sheets. Regeneration of the maxillary bone defect was observed.

CONCLUSION

Induction of osteoblastic differentiation of the dental pulp-derived cell sheets may be indicated for the regeneration of periodontal tissue.

Regeneration of periodontal bone defects with dental pulp stem cells grafting: Systematic Review

Background

The main objective is to evaluate the way to graft the dental pulp stem cells (DPSC) in periodontal defects that best regenerate periodontal tissues. Numerous procedures have been done to promote periodontal regeneration. Bone grafts show good gains clinically and radiographically but histologically seem to have minimal osteoinductive capacity. Another option that exceeds conventional surgery in reducing probing depth and increasing insertion is guided tissue regeneration and tissue engineering that could be an alternative approach to help in the regeneration of living functional bone and peri-dental structures.

Material and Methods

A search was carried out in Cochrane, PubMed-MEDLINE and Scopus databases with keywords: “dental pulp stem cells”, “periodontal regeneration”, “guided tissue regeneration, periodontal”, “tissue regeneration”, “periodontal bone defects”, “periodontal tissue engineering” and “periodontal defect”. Inclusion criteria were articles in English, maximum 10 years old, in which DPSC were used to regenerate a periodontal defect. Exclusion criteria were studies not published in English, case reports, case series, literature reviews, and studies in which periodontal defect was caused by dental extraction.

Results

Out of the 185 articles identified, 101 after excluding duplicates, of which 94 were discarded when reading the title and abstract. 7 articles were obtained for the full text reading: a case report and a case series were eliminated. The systematic review is performed with 5 animal testing studies in vivo. The DPSC sheets regenerate a greater amount of bone than the injection. If HGF (hepatocyte growth factor) is added, the maximum bone volume regenerated (69.3 ± 3.9 mm3; p<0.01) is achieved. Similar results were obtained in all carriers tested except in the controls. The periodontal ligament stem cells (PDLSC) formed more new bone, compared to DPSC (p<0.001). The presence of new cementum and periodontal ligament induced by CMLPs, was detected histologically but DPSC cannot achieve it alone.

Conclusions

Cementum or PDL regeneration does not depend only on DPSC but on other unknown factors. PDLSC has better periodontal regeneration than DPSC. DPSC significantly favours the regeneration of periodontal bone tissue but has few advantages over other grafts. It is necessary to study which growth factors or matrices can enhance their capacity for periodontal regeneration.

Key words:Dental pulp, stem cells, periodontal guided tissue regeneration, periodontal bone loss.

Treatment of Periodontal Bone Defects with Stem Cells from Inflammatory Dental Pulp Tissues in Miniature Swine

Background

Containing a certain proportion of mesenchymal stem cells, inflammatory dental tissue showed great tissue regeneration potential in recent years. However, whether it is applicable to promote tissue regeneration in vivo remains to be elucidated. Therefore, we evaluated the feasibility of stem cells from inflammatory dental pulp tissues (DPSCs-IPs) to reconstruct periodontal defects in miniature pigs.

Methods

The autologous pig DPSCs-IPs were first cultured, appraised and loaded onto β-tricalcium phosphate (β-TCP). The compounds were then engrafted into an artificially-created periodontal defect. Three months later, the extent of periodontal regeneration was evaluated. Clinical examination, radiological examination and immunohistochemical staining were used to assess periodontal regeneration.

Results

The data collectively showed that DPSCs-IPs from miniature pigs expressed moderate to high levels of STRO-1 and CD146 as well as low levels of CD34 and CD45. DPSCs-IPs have osteogentic, adipogenic and chondrogenic differentiation abilities. DPSCs-IPs were engrafted onto β-TCP and regenerated bone to repair periodontal defects by 3 months' post-surgical reconstruction.

Conclusion

Autologous DPSCs-IPs may be a feasible means of periodontal regeneration in miniature pigs.

Clinical Potential and Current Progress of Dental Pulp Stem Cells for Various Systemic Diseases in Regenerative Medicine: A Concise Review

Dental pulp stem cells (DPSCs) are mesenchymal stem cells (MSCs) that have multipotent differentiation and a self-renewal ability. They have been useful not only for dental diseases, but also for systemic diseases. Extensive studies have suggested that DPSCs are effective for various diseases, such as spinal cord injuries, Parkinson's disease, Alzheimer's disease, cerebral ischemia, myocardial infarction, muscular dystrophy, diabetes, liver diseases, eye diseases, immune diseases, and oral diseases. DPSCs have the potential for use in a cell-therapeutic paradigm shift to treat these diseases. It has also been reported that DPSCs have higher regenerative potential than the bone marrow-derived mesenchymal stem cells known as representative MSCs. Therefore, DPSCs have recently gathered much attention. In this review, the therapeutic potential of DPSCs, the latest progress in the pre-clinical study for treatment of these various systemic diseases, and the clinical applications of DPSCs in regenerative medicine, are all summarized. Although challenges, including mechanisms of the effects and establishment of cell processing and transplantation methods for clinical use, still remain, DPSCs could be promising stem cells sources for various clinical applications, because of their easy isolation by a noninvasive procedure without ethical concerns.

Mesenchymal stem cell basic research and applications in dog medicine

The stem cells, owing to their special characteristics like self-renewal, multiplication, homing, immunomodulation, anti-inflammatory, and dedifferentiation are considered to carry an "all-in-one-solution" for diverse clinical problems. However, the limited understanding of cellular physiology currently limits their definitive therapeutic use. Among various stem cell types, currently mesenchymal stem cells are extensively studied for dog clinical applications owing to their readily available sources, easy harvesting, and ability to differentiate both into mesodermal, as well as extramesodermal tissues. The isolated, culture expanded, and characterized cells have been applied both at preclinical as well as clinical settings in dogs with variable but mostly positive results. The results, though positive, are currently inconclusive and demands further intensive research on the properties and their dependence on the applications. Further, numerous clinical conditions of dog resemble to that of human counterparts and thus, if proved rewarding in the former may act as basis of therapy for the latter. The current review throws some light on dog mesenchymal stem cell properties and their potential therapeutic applications.

Periodontal Regeneration by Allogeneic Transplantation of Adipose Tissue Derived Multi-Lineage Progenitor Stem Cells in vivo

The ultimate goal of periodontal disease treatment is the reorganization of functional tissue that can regenerate lost periodontal tissue. Regeneration of periodontal tissues is clinically possible by using autogenic transplantation of MSCs. However, autologous MSC transplantation is limited depending on age, systemic disease and tissue quality, thus precluding their clinical application. Therefore, we evaluated the efficacy of allogeneic transplantation of adipose-derived multi-lineage progenitor cells (ADMPC) in a micro-mini pig periodontal defect model. ADMPC were isolated from the greater omentum of micro-mini pigs, and flow cytometry analysis confirmed that the ADMPC expressed MSC markers, including CD44 and CD73. ADMPC exhibited osteogenic, adipogenic and periodontal ligament differentiation capacities in differentiation medium. ADMPC showed high expression of the immune suppressive factors GBP4 and IL1-RA upon treatment with a cytokine cocktail containing interferon-γ, tumor necrosis factor-α and interleukin-6. Allogeneic transplantation of ADMPC in a micro-mini pig periodontal defect model showed significant bone regeneration ability based on bone-morphometric analysis. Moreover, the regeneration ability of ADMPC by allogeneic transplantation was comparable to those of autologous transplantation by histological analysis. These results indicate that ADMPC have immune-modulation capability that can induce periodontal tissue regeneration by allogeneic transplantation.

Eminent Sources of Adult Mesenchymal Stem Cells and Their Therapeutic Imminence

In the recent times, stem cell biology has garnered the attention of the scientific fraternity and the general public alike due to the immense therapeutic potential that it holds in the field of regenerative medicine. A breakthrough in this direction came with the isolation of stem cells from human embryo and their differentiation into cell types of all three germ layers. However, the isolation of mesenchymal stem cells from adult tissues proved to be advantageous over embryonic stem cells due to the ethical and immunological naivety. Mesenchymal Stem Cells (MSCs) isolated from the bone marrow were found to differentiate into multiple cell lineages with the help of appropriate differentiation factors. Furthermore, other sources of stem cells including adipose tissue, dental pulp, and breast milk have been identified. Newer sources of stem cells have been emerging recently and their clinical applications are also being studied. In this review, we examine the eminent sources of Mesenchymal Stem Cells (MSCs), their immunophenotypes, and therapeutic imminence.

Pulp Regeneration Concepts for Nonvital Teeth: From Tissue Engineering to Clinical Approaches

Following the basis of tissue engineering (Cells-Scaffold-Bioactive molecules), regenerative endodontic has emerged as a new concept of dental treatment. Clinical procedures have been proposed by endodontic practitioners willing to promote regenerative therapy. Preserving pulp vitality was a first approach. Later procedures aimed to regenerate a vascularized pulp in necrotic root canals. However, there is still no protocol allowing an effective regeneration of necrotic pulp tissue either in immature or mature teeth. This review explores in vitro and preclinical concepts developed during the last decade, especially the potential use of stem cells, bioactive molecules, and scaffolds, and makes a comparison with the goals achieved so far in clinical practice. Regeneration of pulp-like tissue has been shown in various experimental conditions. However, the appropriate techniques are currently in a developmental stage. The ideal combination of scaffolds and growth factors to obtain a complete regeneration of the pulp-dentin complex is still unknown. The use of stem cells, especially from pulp origin, sounds promising for pulp regeneration therapy, but it has not been applied so far for clinical endodontics, in case of necrotic teeth. The gap observed between the hope raised from in vitro experiments and the reality of endodontic treatments suggests that clinical success may be achieved without external stem cell application. Therefore, procedures using the concept of cell homing, through evoked bleeding that permit to recreate a living tissue that mimics the original pulp has been proposed. Perspectives for pulp tissue engineering in the near future include a better control of clinical parameters and pragmatic approach of the experimental results (autologous stem cells from cell homing, controlled release of growth factors). In the coming years, this therapeutic strategy will probably become a clinical reality, even for mature necrotic teeth.

Human intrabony defect regeneration with micrografts containing dental pulp stem cells: A randomized controlled clinical trial

AIM

The goal of this study was to evaluate if dental pulp stem cells (DPSCs) delivered into intrabony defects in a collagen scaffold would enhance the clinical and radiographic parameters of periodontal regeneration.

MATERIALS AND METHODS

In this randomized controlled trial, 29 chronic periodontitis patients presenting one deep intrabony defect and requiring extraction of one vital tooth were consecutively enrolled. Defects were randomly assigned to test or control treatments which both consisted of the use of minimally invasive surgical technique. The dental pulp of the extracted tooth was mechanically dissociated to obtain micrografts rich in autologous DPSCs. Test sites (n = 15) were filled with micrografts seeded onto collagen sponge, whereas control sites (n = 14) with collagen sponge alone. Clinical and radiographic parameters were recorded at baseline, 6 and 12 months postoperatively.

RESULTS

Test sites exhibited significantly more probing depth (PD) reduction (4.9 mm versus 3.4 mm), clinical attachment level (CAL) gain (4.5 versus 2.9 mm) and bone defect fill (3.9 versus 1.6 mm) than controls. Moreover, residual PD < 5 mm (93% versus 50%) and CAL gain ≥4 mm (73% versus 29%) were significantly more frequent in the test group.

CONCLUSIONS

Application of DPSCs significantly improved clinical parameters of periodontal regeneration 1 year after treatment.

Outcomes of Alveolar Ridge Preservation With Recombinant Human Bone Morphogenetic Protein-2: A Systematic Review

PURPOSE

The main focused question of this systematic review was as follows: Does the application of recombinant human bone morphogenetic protein-2 (rhBMP-2) placed in extraction sockets reduce the alveolar ridge changes?

METHODS

A systematic literature search was performed up to February 2017. Clinical studies published in English were included. Outcome variables of interest were as follows: changes in alveolar ridge width and height, the quality of new bone, patient's safety, adverse events, and postoperative complications.

RESULTS

Seven articles were included. Because of the vast heterogeneity and high risk of bias among the studies, performing a meta-analysis deemed not feasible. Application of rhBMP-2 in the extraction socket was more effective in the reduction of ridge width compared with that of ridge height. The superiority of 1.5 mg/mL rhBMP-2/absorbable collagen sponge over the carrier alone on alveolar ridge width/height remodeling was more significant when it was applied in the sockets with ≥50% buccal bone dehiscence. The limited available data showed that rhBMP-2 did not improve the quality of new bone. Antibodies against rhBMP-2 were detected in the serum in 1 trial.

CONCLUSIONS

Within the limits of this review, 1.5 mg/mL rhBMP-2 might be beneficial for preserving the alveolar ridge width within extraction sockets given as to whether the cost-effectiveness is justifiable. Studies with lower risk of bias should be performed to confirm the above findings.

Cementum regeneration using stem cells in the dog model: A systematic review

OBJECTIVE

Restoring lost tissues of the periodontium, such as cementum, is essential in reducing the risk of tooth loss due to periodontitis and/or severe root resorption. Stem cell therapy is a regenerative strategy in cementum regeneration. This systematic review aimed to analyze the effect of various stem cells and their transplantation method on cementum regeneration in the dog model.

METHODS

Electronic databases were searched, in addition to performing hand searches and a gray literature search. Titles and abstracts were searched according to the inclusion criteria and full texts were selected to be included in this systematic review. Data was extracted from each article and risk of bias was assessed for individual studies.

RESULTS

Most studies reported that the treatment using a variety of stem cells resulted in significantly greater cementum regeneration.

CONCLUSIONS

Because of variations in additional factors included in each study and varied risk of bias among those studies, the effect of each type of stem cell on cementum regeneration in dogs is difficult to clarify. Additional information needs to be obtained from each study in order to further analyze the individual effect of stem cells on cementum regeneration in dogs.

Use of Autologous Stem Cells for the Regeneration of Periodontal Defects in Animal Studies: a Systematic Review and Meta-Analysis

OBJECTIVES

To overview preclinical animal trials and quantify the effect size that stem cell therapy has on the regeneration of periodontal tissue complex.

MATERIAL AND METHODS

A systematic MEDLINE (PubMed) online library search was conducted for preclinical animal studies in vivo , using autologous periodontal ligament, dental pulp, cementum, alveolar periosteal, gingival margin or adipose stem cell types for periodontal tissue complex regeneration purposes. Studies had to be published between 2007.09.01 and 2017.09.01 in the English language.

RESULTS

Online library search yielded 2099 results. After the title, abstract and full-text screening ten studies fit inclusion criteria and were pooled into meta-analysis. Overall the stem cell regenerative therapy had a statistically significant positive influence on the periodontal tissue regeneration when compared to the control groups. The biggest influence was made to the regeneration of cementum (standardised mean difference [SMD] 2.25 [95% confidence interval (CI) = 1.31 to 3.2]) while the smallest influence was made to the alveolar bone (SMD 1.47 [95% CI = 0.7 to 2.25]) the effect size for periodontal ligament regeneration was (SMD 1.8 [95% CI = 1 to 2.59]). Subgroup analysis showed statistically significant (P < 0.05) differences between different cell types in the alveolar bone and cementum regeneration groups and in alveolar bone group in relation to scaffold materials.

CONCLUSIONS

Stem cell therapy has a positive impact on periodontal tissue complex regeneration. Such therapy has the biggest influence on cementum regeneration meanwhile alveolar bone regeneration is influenced by the least amount. However more and less diverse preclinical studies are needed to have a greater statistical power in future meta-analyses.

Mesenchymal Stem Cells of Dental Origin for Inducing Tissue Regeneration in Periodontitis: A Mini-Review

Periodontitis is a chronic disease that begins with a period of inflammation of the supporting tissues of the teeth table and then progresses, destroying the tissues until loss of the teeth occurs. The restoration of the damaged dental support apparatus is an extremely complex process due to the regeneration of the cementum, the periodontal ligament, and the alveolar bone. Conventional treatment relies on synthetic materials that fill defects and replace lost dental tissue, but these approaches are not substitutes for a real regeneration of tissue. To address this, there are several approaches to tissue engineering for regenerative dentistry, among them, the use of stem cells. Mesenchymal stem cells (MSC) can be obtained from various sources of adult tissues, such as bone marrow, adipose tissue, skin, and tissues of the orofacial area. MSC of dental origin, such as those found in the bone marrow, have immunosuppressive and immunotolerant properties, multipotency, high proliferation rates, and the capacity for tissue repair. However, they are poorly used as sources of tissue for therapeutic purposes. Their accessibility makes them an attractive source of mesenchymal stem cells, so this review describes the field of dental stem cell research and proposes a potential mechanism involved in periodontal tissue regeneration induced by dental MSC.

Mesenchymal Stem Cells and Calcium Phosphate Bioceramics: Implications in Periodontal Bone Regeneration

In orthopedic medicine, a feasible reconstruction of bone structures remains one of the main challenges both for healthcare and for improvement of patients' quality of life. There is a growing interest in mesenchymal stem cells (MSCs) medical application, due to their multilineage differentiation potential, and tissue engineering integration to improve bone repair and regeneration. In this review we will describe the main characteristics of MSCs, such as osteogenesis, immunomodulation and antibacterial properties, key parameters to consider during bone repair strategies. Moreover, we describe the properties of calcium phosphate (CaP) bioceramics, which demonstrate to be useful tools in combination with MSCs, due to their biocompatibility, osseointegration and osteoconduction for bone repair and regeneration. Also, we overview the main characteristics of dental cavity MSCs, which are promising candidates, in combination with CaP bioceramics, for bone regeneration and tissue engineering. The understanding of MSCs biology and their interaction with CaP bioceramics and other biomaterials is critical for orthopedic surgical bone replacement, reconstruction and regeneration, which is an integrative and dynamic medical, scientific and bioengineering field of research and biotechnology.

Therapeutic effects of hepatocyte growth factor-overexpressing dental pulp stem cells on liver cirrhosis in a rat model

Cirrhosis is the terminal stage of hepatic diseases and is prone to develop into hepatocyte carcinoma. Increasing evidence suggests that the transplantation of dental pulp stem cells (DPSCs) may promote recovery from cirrhosis, but the key regulatory mechanisms involved remain to be determined. In this study, we overexpressed human hepatocyte growth factor (hHGF) in primary rat DPSCs and evaluated the effects of HGF overexpression on the biological behaviors and therapeutic efficacy of grafted DPSCs in cirrhosis. Liver cirrhosis was induced via the intraperitoneal injection of CCl₄ twice weekly for 12 weeks and was verified through histopathological and serological assays. HGF was overexpressed in DPSCs via transduction with a hHGF-lentiviral vector and confirmed based on the elevated expression and secretion of HGF. The HGF-overexpressing DPSCs were transplanted into rats intravenously. The HGF-overexpressing DPSCs showed increased survival and hepatogenic differentiation in host liver tissue at 6 weeks after grafting. They also exhibited a significantly greater repair potential in relation to cirrhosis pathology and impaired liver function than did DPSCs expressing HGF at physiological levels. Our study may provide an experimental basis for the development of novel methods for the treatment of liver cirrhosis in clinical practice.

Stem cell-based tooth and periodontal regeneration

Currently regeneration of tooth and periodontal damage still remains great challenge. Stem cell-based tissue engineering raised novel therapeutic strategies for tooth and periodontal repair. Stem cells for tooth and periodontal regeneration include dental pulp stem cells (DPSCs), periodontal ligament stem cells (PDLSCs), stem cells from the dental apical papilla (SCAPs), and stem cells from human exfoliated deciduous teeth (SHEDs), dental follicle stem cells (DFSCs), dental epithelial stem cells (DESCs), bone marrow mesenchymal stem cells (BMMSCs), adipose-derived stem cells (ADSCs), embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). To date, substantial advances have been made in stem cell-based tooth and periodontal regeneration, including dentin-pulp, whole tooth, bioroot and periodontal regeneration. Translational investigations have been performed such as dental stem cell banking and clinical trials. In this review, we present strategies for stem cell-based tissue engineering for tooth and periodontal repair, and the translational studies.

In Vitro and In Vivo Dentinogenic Efficacy of Human Dental Pulp-Derived Cells Induced by Demineralized Dentin Matrix and HA-TCP

Human dental pulp cells have been known to have the stem cell features such as self-renewal and multipotency. These cells are differentiated into hard tissue by addition of proper cytokines and biomaterials. Hydroxyapatite-tricalcium phosphates (HA-TCPs) are essential components of hard tissue and generally used as a biocompatible material in tissue engineering of bone. Demineralized dentin matrix (DDM) has been reported to increase efficiency of bone induction. We compared the efficiencies of osteogenic differentiation and in vivo bone formation of HA-TCP and DDM on human dental pulp stem cells (hDPSCs). DDM contains inorganic components as with HA-TCP, and organic components such as collagen type-1. Due to these components, osteoinduction potential of DDM on hDPSCs was remarkably higher than that of HA-TCP. However, the efficiencies of in vivo bone formation are similar in HA-TCP and DDM. Although osteogenic gene expression and bone formation in immunocompromised nude mice were similar levels in both cases, dentinogenic gene expression level was slightly higher in DDM transplantation than in HA-TCP. All these results suggested that in vivo osteogenic potentials in hDPSCs are induced with both HA-TCP and DDM by osteoconduction and osteoinduction, respectively. In addition, transplantation of hDPSCs/DDM might be more effective for differentiation into dentin.