Methods of Isolation and Characterization of Stem Cells from Different Regions of Oral Cavity Using Markers: A Systematic Review

A Review of Stem Cell Attributes Derived from the Oral Cavity

Oral cavity stem cells (OCSCs) have been the focus of intense scientific efforts due to their accessibility and stem cell properties. The present work aims to compare the different characteristics of 6 types of dental stem cells derived from the oral cavity: dental pulp stem cells (DPSC), stem cells from human exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSC), stem cells from the apical papilla (SCAP), bone marrow mesenchymal stem cells (BMSC), and gingival mesenchymal stem cells (GMSC). Using immunofluorescence and real-time polymerase chain reaction techniques, we analysed the cells for stem cell, differentiation, adhesion, and extracellular matrix markers; the ability to proliferate in vitro; and multilineage differentiation potential. Markers such as vimentin, CD44, alkaline phosphatase, CD146, CD271, CD49f, Oct 3/4, Sox 9, FGF7, nestin, and BMP4 showed significant differences in expression levels, highlighting the heterogeneity and unique characteristics of each cell type. At the same time, we confirmed that all cell types successfully differentiated into osteogenic, chondrogenic, or adipose lineages, with different readiness. In conclusion, our study reveals the distinct properties and potential applications of various dental-derived stem cells. These findings contribute to a deeper understanding of OCSCs and their significance in future clinical applications.

Protective role of stem cells in POI: Current status and mechanism of action, a review article

Premature ovarian insufficiency (POI) has far-reaching consequences on women's life quality. Due to the lack of full recognition of the etiology and complexity of this disease, there is no appropriate treatment for infected patients. Recently, stem cell therapy has attracted the attention of regenerative medicine scholars and offered promising outcomes for POI patients. Several kinds of stem cells, such as embryonic stem cells (ESCs), mesenchymal stem cells (MSCs), and induced pluripotent stem cells (iPSCs) have been used for the treatment of ovarian diseases. However, their potential protective mechanisms are still unknown. Undoubtedly, a better understanding of the therapeutic molecular and cellular mechanisms of stem cells will address uncover strategies to increase their clinical application for multiple disorders such as POI. This paper describes a detailed account of the potential properties of different types of stem cells and provides a comprehensive review of their protective mechanisms, particularly MSC, in POI disorder. In addition, ongoing challenges and several strategies to improve the efficacy of MSC in clinical use are addressed. Therefore, this review will provide proof-of-concept for further clinical application of stem cells in POI.

Establishing and characterizing human stem cells from the apical papilla immortalized by hTERT gene transfer

Stem cells from the apical papilla (SCAPs) are promising candidates for regenerative endodontic treatment and tissue regeneration in general. However, harvesting enough cells from the limited apical papilla tissue is difficult, and the cells lose their primary phenotype over many passages. To get over these challenges, we immortalized human SCAPs with lentiviruses overexpressing human telomerase reverse transcriptase (hTERT). Human immortalized SCAPs (hiSCAPs) exhibited long-term proliferative activity without tumorigenic potential. Cells also expressed mesenchymal and progenitor biomarkers and exhibited multiple differentiation potentials. Interestingly, hiSCAPs gained a stronger potential for osteogenic differentiation than the primary cells. To further investigate whether hiSCAPs could become prospective seed cells in bone tissue engineering, in vitro and in vivo studies were performed, and the results indicated that hiSCAPs exhibited strong osteogenic differentiation ability after infection with recombinant adenoviruses expressing BMP9 (AdBMP9). In addition, we revealed that BMP9 could upregulate ALK1 and BMPRII, leading to an increase in phosphorylated Smad1 to induce the osteogenic differentiation of hiSCAPs. These results support the application of hiSCAPs in tissue engineering/regeneration schemes as a stable stem cell source for osteogenic differentiation and biomineralization, which could be further used in stem cell-based clinical therapies.

Potential of Mesenchymal Stem Cell Sheets on Periodontal Regeneration: A Systematic Review of Pre-Clinical Studies

BACKGROUND

Cell sheet technique using mesenchymal stem cells is a high-level strategy in periodontal regenerative medicine. Although recent studies have shown the role of MSCSs in increased dental supporting tissues and bone, there is no systematic review focused specifically on assessing periodontal regeneration in orthotopic animal models.

OBJECTIVE

To evaluate the potential of mesenchymal stem cell sheets (MSCSs) on periodontal regeneration, compared to control, in experimental animal models Methods: Pre-clinical studies in periodontal defects of animal models were considered eligible. The electronic search included the MEDLINE, Web of Science, EMBASE and LILACS databases. The review was conducted according to the Preferred Reporting Item for Systematic Reviews and Meta-Analyses statement guidelines.

RESULTS

A total of 17 of the 3989 studies obtained from the electronic database search were included. MSCSs included dental follicle (DF) MSCSs, periodontal ligament (PL) MSCSs, dental pulp (DP) MSCSs, bone marrow (BM) MSCSs, alveolar periosteal (AP) MSCSs and gingival (G) MSCSs. Regarding cell sheet inducing protocol, most of the studies used ascorbic acid (52.94%). Others used culture dishes grafted with a temperature-responsive polymer (47.06%). Adverse effects were not identified in the majority of studies. Meta-analysis was not considered because of methodological heterogeneities. PDL-MSCSs were superior for periodontal regeneration enhancement compared to the control, but in an induced inflammatory microenvironment, DF-MSCSs were better. Moreover, DF-MSCSs, DP-MSCSs, and BM-MSCSs showed improved results compared to the control.

CONCLUSION

MSCSs can improve periodontal regeneration in animal periodontal defect models.

Periodontal ligament stem cell-based bioactive constructs for bone tissue engineering

Objectives: Stem cell-based tissue engineering approaches are promising for bone repair and regeneration. Periodontal ligament stem cells (PDLSCs) are a promising cell source for tissue engineering, especially for maxillofacial bone and periodontal regeneration. Many studies have shown potent results via PDLSCs in bone regeneration. In this review, we describe recent cutting-edge researches on PDLSC-based bone regeneration and periodontal tissue regeneration. Data and sources: An extensive search of the literature for papers related to PDLSCs-based bioactive constructs for bone tissue engineering was made on the databases of PubMed, Medline and Google Scholar. The papers were selected by three independent calibrated reviewers. Results: Multiple types of materials and scaffolds have been combined with PDLSCs, involving xeno genic bone graft, calcium phosphate materials and polymers. These PDLSC-based constructs exhibit the potential for bone and periodontal tissue regeneration. In addition, various osteo inductive agents and strategies have been applied with PDLSCs, including drugs, biologics, gene therapy, physical stimulation, scaffold modification, cell sheets and co-culture. Conclusoin: This review article demonstrates the great potential of PDLSCs-based bioactive constructs as a promising approach for bone and periodontal tissue regeneration.

Awareness on the management strategy of stitch abscess among dental students

Stitch abscesses are abscesses that develop following surgical procedures as a result of suture infections. Because of nonabsorbable sutures, the material reacts with connective tissue, generating adhesions around the stitch. The use of this type of material increases the risk of infection. The aim of this study was to establish awareness on the management strategy of suture stitch abscess among dental students. An online survey consisting of ten questions about suture stitch abscess along with sociodemographic factors was circulated among equal numbers of 2^nd years, 3^rd years, final years, and compulsory rotatory residential internship (CRRI). The data obtained from the questionnaire were transferred to Microsoft Excel and imported to SPSS software for statistical analysis. Interns are more aware about the complications and management strategy of suture stitch abscesses compared to others. Awareness on the management strategy of suture stitch abscess is important, and it helps to reduce the side effects to improve the outcomes. Educating the risk factors, signs and symptoms, and management strategy is the best way to help raise awareness.

Knowledge, attitude, and practice survey on the use of stamp technique for the management of Class I caries in molars among undergraduate students in dental schools

Stamp technique is a recently developed technique that involves of creating an index which records the occlusal anatomy of posterior teeth before cavity preparation. This technique is beneficial in cases where the caries is involving the occlusal surface with little or no damage to the occlusal anatomy or the marginal ridges. The aim of the study is to assess the knowledge and practice on the use of stamp technique for the management of Class 1 caries in molars among undergraduate students. A questionnaire-based study was conducted among 100 dental students in Saveetha Dental College. The questionnaire contained 17 questions that were circulated through Google Forms and received dichotomous responses. The data were collected as an ordinal variable and the collected data were analyzed using SPSS software, and Chi-square test and descriptive analysis were done. This study shows that almost 37% of the respondents were interns and final-year students, 62% of them felt carving would be easier to attain the proper occlusal morphology, 55% of them prefer both flowable and packable composites, and 63% felt stamp technique would be technique sensitive. There was a significant association between the year of study and difficulties faced in occlusal stamp technique (P = 0.014 < 0.05). Undergraduate students were moderately aware of the stamp technique in composite restorations. More detailed knowledge on composite finishing and polishing should be emphasized in the undergraduate curriculum.

Knowledge and awareness of forensic dentistry course among undergraduates

Forensic odontology is an expanding field within the domain of forensic sciences, where dental knowledge is applied in identification of individuals through analysis of the dental-related records. The study goal was to determine if undergraduate students were aware of the forensic dentistry course. A cross-sectional survey was initiated about the need for forensic courses in UG program. Nearly 100 students participated in this survey, data have been collected, and graph has been plotted. Data have been collected with the help of SPSS software; data have been analyzed and plotted as graph. One hundred students responded the survey; only limited people's opinions have been collected. The result varies among the students; 58% knows about the importance of forensic odontology in dentistry using Chi-square value, P = 0.09. The majority of students, who replied to this poll, had some understanding and awareness of forensic odontology in dentistry, but they need to learn more about how it is practiced.

Current status of usage of ivermectin in the management of COVID

The antibacterial, antiviral, and anticancer properties of ivermectin make it a wonder drug with a wide range of possible applications. It works against a variety of microorganisms, including viruses. Ivermectin has a wide range of antiviral effects, according to in vivo research in animal models. Because ivermectin is involved in a range of biological processes, it could be a promising therapeutic candidate for viruses such as COVID-19 and other positive-sense single-stranded RNA viruses. The study aims to analyze the awareness about the current status of usage of ivermectin in management of COVID among students studying in a private dental college. A study based on questionnaire was organized among students studying in a private dental college in Tamil Nadu. The subjects were asked a series of structural questions based on the usage of ivermectin in management of COVID. The questionnaire was prepared with 10 questions. 150 individuals completed the questionnaire; all of their answers were tallied in excel and imported into SPSS. For statistical analysis, the Chi-square test was performed. Excel was used to tabulate and enter the data, and the SPSS package software was used to analyze it. The study's threshold for statistical significance was set at P < 0.05. From this study, we found that the students had limited knowledge about the usage of ivermectin for management of COVID. More studies should be conducted to widen the knowledge among the students about the current affairs of the world.

Evaluation of accuracy and time taken to make an open tray implant impressions with two techniques

Implant dentistry's emergence and acceptance have provided physicians with a wide range of new options for fixed and removable rehabilitation. The eventual replacement of the lost tooth is the ultimate success, and this can be accomplished using recognized prosthodontic methods. The present study aims to evaluate the time and dimensional accuracy of implant definitive models with an open tray impression with two different techniques. Impression was made in two different techniques and the cast was poured and checked for the time taken and the accuracy of the impression. In IBM SPSS software version 23.0 all the results were statistically analyzed. An Independent t-test was performed for the parameters. No statistically significant difference was present (P > 0.05) when comparing the accuracy and time taken between the two groups. It is concluded that time taken and the misfit is less for modified open tray impression techniques when compared to the regular open tray impression.

Practice management in undergraduate dental program: The need among dental students

The objective of this study is to assess the opinion of dental students regarding the necessity for a practice management (PM) course in their curriculum. To determine the necessity of a PM course in dental programs, a series of questions was developed and given to 100 dental students. Dental students were asked a series of questions about the necessity of this course, and responses were gathered. The questionnaire included time management, patient management, teamwork, leadership quality, and other requirements of the course. According to the results, dentistry students desired that the PM curriculum cover subjects such as teamwork, confidence, the value of the PM course, time management, patient management abilities, leadership qualities, and others. Most of the responses obtained from the students agreed that the PM curriculum must be taught with the course for better management. The development of any course should be based on the need and opinion of the students who pursue the course of dentistry. Thus, this study evaluates the need for a PM course in an undergraduate (UG) dental program.

Need for practice management in undergraduate dental program - A cross sectional survey among the dentists

Advancement in technology, enhancement of knowledge, elevated expectations from the patients regarding the quality of treatment, and economic factors are emerging as challenges to dentists, which demand emerging dentists to have skills on patient management and leadership through an improved curriculum. The aim of the present study was to conduct a survey among dentists regarding the need for practice management in undergraduate dental program. A total of 100 dentists from Chennai were involved in the study. They were made to answer 15 questions which were circulated online. The obtained data were statistically analyzed using SPSS software. It is evident that the majority of the dentists emphasize on including practice management courses in the undergraduate dental program as it may be helpful for the budding dentists in their future private practices. It can be concluded that the opinion of the dentists is strong and beneficial and should be considered.

Presence of impacted supernumerary teeth in the Indian population

A tooth that does not erupt into the dental arch during the anticipated developmental window is said to be impacted. A supernumerary tooth (ST) would be any dentition or odontogenic entity that grows from a tooth germ more often than is typical for a particular area of the dental arch (ST). The study's goal is to determine how commonly impacted supernumerary teeth are present within the Indian community. This research project at the institution which was retrospective was done on dental patients who went to the private dental hospital between March 2020 and March 2021. We looked over the medical records of 86,000 patients at the private dental institution and analyzed the data. In the study's 74,421 impaction cases, 139 instances of impacted extra teeth were found. For statistical analysis, collected data were analyzed, entered into an Excel document, and imported into SPSS version 21. In the study population, males between the ages of 21 and 35 years were more frequently observed to have supernumerary impacted teeth. Impacted teeth were more frequently observed in the posterior region rather than the anterior region. Within the constraints of the study, it was shown that males between the ages of 21 and 35 years and the posterior part of the mouth experienced impacted supernumerary teeth the most frequently.

Awareness on resonance frequency analysis in dental implantology among dental practitioners and dental students

In a partial or entirely independent jaw, oral implantology is a technique in dentistry used to enhance the function of mastication, esthetics, and phonation. An important diagnostic aspect for the effectiveness of implant therapy is the stability of the implants. This study aims to measure dental professionals' and dental students' knowledge of resonance frequency analysis (RFA) in dental implantology. This study aims to measure dental professionals' and dental students' knowledge of RFA in dental implantology. One hundred ninety-nine dentists and dental students participated in an online survey study that was delivered through Google Forms. For statistical analysis, tabulated data from the Excel sheets were transferred into the SPSS program. The Chi-square test is also used to examine clinical relevance. According to the study's findings, 60% of the respondents were male and 46% of those who responded were dental professionals. The respondents were primarily between the ages of 18 and 22 (36%). The majority of dental undergraduates and graduates were found to be knowledgeable about the various techniques used to gauge implant stability (P = 0.04 < 0.05). Within the limitations of this study, it was found that most of the dental students and dental practitioners participating in this study were aware of implant stability. The majority of the respondents were aware that RFA was used to measure primary and secondary stability and osseointegration.

Knowledge, awareness, and practice survey on conventional radiographic methods and processing among dental students

X-rays are electromagnetic waves produced by an X-ray machine and are used to observe the internal structures of patients. The X-rays pass through the body before being detected by the detector file or a digital detector behind the patient. To analyze the knowledge, awareness, and practice on conventional radiographic method and processing among the dental students. A well-framed questionnaire consisting of 10 questions were prepared and distributed among 100 dental professionals and students through the online Google forms link. The data were collected, tabulated in Excel sheets, and analyzed using the SPSS software. The Chi-square test was used to assess the P value. Sixty-five percentage of the participants are aware of conventional radiographic methods and 35% are not aware. The Chi-square test was done giving a P = 0.001 (<0.05), which is statistically significant. The dental students as compared to the other specialties have adequate and efficient knowledge and are aware of the conventional radiographic methods and its processing.

Expectation of treatment outcomes in complete denture wearers

Edentulism is a condition associated with age, and the outcome of prosthodontic treatment depends on a number of dental and nondental factors. In complete denture therapy, patient satisfaction is a key objective and various other variables affect this parameter. The ability to foresee its preferences may assist dentists in making informed treatment selections. The study purpose is to assess the expectations of treatment outcomes in complete denture users. For the study, all cases referred for total denture therapy during September 2020 and February 2021 were included. Both new and old denture users completed questionnaires on factors such as retention, mastication, phonetics, esthetics, and comfort. Excel was used to compile the data, which was then imported into SPSS for statistical analysis. The study's statistical significance level was established at P < 0.05. Male patients over the age of 60 years wearing dentures were very common. Denture wearers were highly prevalent in the age group of >60 years among male patients. Retention, esthetics, and phonetics are highly satisfied in existing denture wearers and mastication is highly satisfied in new denture wearers. The comfort factor is commonly satisfied in both the denture wearers. The results were statistically significant with a P = 0.05. Clinician can plan their treatments more effectively if they are aware of the treatment's expectations.

Awareness on current status of usage of ritonavir in the management of covid among dental students

Ritonavir's pharmacodynamics raise questions regarding whether medication concentrations high enough to block the SARS-CoV-2 proteases can be obtained. Ritonavir may have a therapeutic benefit at any stage of the disease, although pharmacodynamic issues and the absence of clinical benefit data among hospitalized COVID-19 patients cast doubt on this claim. To study the awareness on current status of usage of ritonavir in the management of COVID among dental students. This study, which is survey-based, involved a sample of 100 individuals and was carried out on the website Survey Planet. The study included undergraduate and graduate dental students. The dental students were given a questionnaire containing 10 questions. Their responses were gathered. The number and percentage were used to summarize the data. Dental students from Chennai showed adequate knowledge of COVID-19 in the medical environment. Postgraduate students were more aware about the current status of usage of Ritonavir for COVID-19. This study demonstrates the urgent necessity for all health-care workers to regularly implement educational interventions and training program on infection control procedures for COVID-19.

Chronic metabolic and induced stress impacts mesenchymal stromal cell differentiation and modulation of dental origin in-vitro

The impact of induced (smoking) and metabolic stress (diabetes) on dental stem cells with respect to pre-impact consideration on differentiation and bone formation were investigated. The progenitor stem cells isolated from dental pulp, follicle and gingival tissues were phenotyped and subjected to nicotine and high glucose stress mimicking the smoking and diabetic condition in-vitro. The results showed that the cellular viability post treatment with 100 µM nicotine and 10uM glucose was about 86% to 89% respectively in all the three cell types while about 73% in combined nicotine and glucose treatment. No variation in the expression of pro-inflammatory TNF-α, IL-1β and IL-12 in all the three cell types were noticed. The observed viability in nicotine treated cells were due to elevated IL-6, IL-10 while in glucose was due to brain derived neurotropic factor (BDNF). Higher expression of IL-4, IL-6, IL-10, TGF-β and heme oxygenase −1 (HO-1) were found high in both stressors treated cells. Differentiation and mineralization markers Alkaline phosphatase (ALP), Collagenase I (COL1), Osteocalcin, Runt related transcription factor 2 (RUNX2), Osteopontin and Bone sialoprotein were expressed in the dental pulp stem cells (DPSCs) and gingival mesenchymal stem cells (GMSCs) at varying levels post nicotine or glucose treatment while not significantly observed in dental follicular stem cells (DFSCs). Therefore, it is evident that the stem cells of varied dental origin responded to the stress are more or less uniform with physiological delay in differentiation into osteoblast. It is evident from the study that, the metabolic or induced stress subverts the process of regenerative healing by mesenchymal stromal cells with their anatomical niche.

miR-141-3p Regulates EZH2 to Attenuate Porphyromonas gingivalis Lipopolysaccharide-Caused Inflammation and Inhibition of Osteogenic Differentiation in Human Periodontal Ligament Stem Cells

Objective

miR-141-3p has been demonstrated to be both anti-inflammatory and osteoprotective. This study is aimed at investigating the effect of miR-141-3p on osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs) stimulated by Porphyromonas gingivalis lipopolysaccharide (PgLPS) and its mechanism.

Methods

PgLPS was used to induce an inflammatory environment, and overexpression of miR-141-3p was done to assess its effect on hPDLSCs in an inflammatory environment. The level of miR-141-3p and EZH2 in hPDLSCs from each treatment group was detected via qRT-PCR, and the inflammatory factors IL-6 and IL-8 in the supernatant of each group were detected by ELISA. ALP staining and alizarin red staining were used to assess the effect of miR-141-3p on the osteogenic differentiation ability of hPDLSCs, and also, western blot was used to detect expression of osteogenic differentiation-related proteins. Further, dual-luciferase reporter assay examined whether miR-141-3p targeted EZH2.

Results

PgLPS led to a significant decrease of miR-141-3p in hPDLSCs. Overexpression of miR-141-3p could enhance ALP activity and alizarin red staining intensity and increase Runx2, OPN and OCN protein expression levels in PgLPS-treated hPDLSCs. Additionally, miR-141-3p could reduce IL-6 and IL-8. miR-141-3p could target and negatively regulate EZH2, and overexpression of EZH2 reversed the promoting effect of miR-141-3p on osteogenic differentiation.

Conclusion

miR-141-3p can attenuate PgLPS-induced inhibition of osteogenic differentiation and inflammation in hPDLSCs by negatively regulating EZH2.

A Narrative Review: Gingival Stem Cells as a Limitless Reservoir for Regenerative Medicine

The gingival tissue can be collected in an easy way and represent an accessible source to isolate gingival-derived mesenchymal stem cells (GMSCs). GMSCs are a subpopulation of dental-derived mesenchymal stem cells that show the mesenchymal stem cells (MSCs) features, such as differentiation abilities and immunomodulatory properties. Dental-derived stem cells are also expandable in vitro with genomic stability and the possibility to maintain the stemness properties over a prolonged period of passages. Moreover, several preclinical studies have documented that the extracellular vesicles (EVs) released from GMSCs possess similar biological functions and therapeutic effects. The EVs may represent a promising tool in the cell-free regenerative therapy approach. The present review paper summarized the GMSCs, their multi-lineage differentiation capacities, immunomodulatory features, and the potential use in the treatment of several diseases in order to stimulate tissue regeneration. GMSCs should be considered a good stem cell source for potential applications in tissue engineering and regenerative dentistry.

Soft tissue re-growth after different crown lengthening techniques among Indian patients

Patients often report complaining of fractured or decayed teeth with severe morphological deformities. However, all these clinical scenarios require the same level of care and consideration to rehabilitate form, function and esthetics. Some cases have sufficient clinical crown height while others often require an interdisciplinary approach in the form of orthodontic/surgical extrusion or surgical periodontal options. A common factor delaying treatment is soft tissue regrowth after crown lengthening which delays the impression required for final prosthesis. Therefore, it is of interest to compare the prevalence of soft tissue regrowth a week after different crown lengthening techniques including laser gingivectomy, electrocautery gingivectomy, modified Widman flap and apically repositioned. The parameters assessed included 1-week postoperative soft tissue regrowth after crown lengthening, age of patients and gender. It was observed that laser and electrocautery-assisted gingivectomy had a higher rate of soft tissue regrowth as compared to surgical techniques. It was further noted that laser and electrocautery assisted gingivectomy had a higher frequency of soft tissue rebound growth compared to surgical crown lengthening using modified widman flap and apically repositioned flap, which was statistically insignificant. Patients within the age groups of 26-60 years were found to have a higher tendency of soft tissue regrowth, which was found to be clinically and statistically significant (p<0.05).

Isolation, Characterization, and Differentiation of Stem Cells From Various Dental Sources: An In Vitro Study

Aim:

The aim of the current study was to isolate stem cells from various dental sources such as dental pulp, periodontal ligament (PDL), and apical papilla, and to characterize stem cells by staining for the presence/absence of specific surface markers and also to differentiate stem cells into osteogenic, chondrogenic, and adipogenic cell lineages by exposing them to specific growth factors under the ideal conditions.

Materials and Methods:

A total of 117 samples were included in the study, consisting of 30 pulp, 50 gingival, 35 PDL, and 2 apical papilla samples. The pulp was extirpated and transported to the Central Research Laboratory. Gingival connective tissue was collected from the participants undergoing any crown lengthening procedure or any gingivectomy procedure from the Department of Periodontology. A similar procedure was also followed for apical papilla and PDL. Isolation was done followed by the identification of the cells by immunocytochemistry using different markers. Once the identity of cells was confirmed, these cells were treated with different culture media to attain 70% to 100% confluency. Then the medium was replaced with a conditioning medium containing specific growth factors for differentiation into osteogenic, chondrogenic, and adipogenic cell lineages.

Result:

In our study, the number of samples collected and processed was 117. The isolation rate of stem cells from the above-collected samples was 70%. Statistical analysis—no statistical analysis was done as there was no variability expected.

Conclusion:

Our study showed that stem cells could be isolated, differentiated, and characterized from different dental sources.

Effects of rhBMP-2 on Bone Formation Capacity of Rat Dental Stem/Progenitor Cells from Dental Follicle and Alveolar Bone Marrow

Dental stem/progenitor cells are a promising cell sources for alveolar bone (AB) regeneration because of their same embryonic origin and superior osteogenic potential. However, their molecular processes during osteogenic differentiation remain unclear. The objective of this study was to identify the responsiveness of dental follicle cells (DFCs) and AB marrow-derived mesenchymal stem cells (ABM-MSCs) to recombinant human bone morphogenetic protein-2 (rhBMP-2). These cells expressed vimentin and MSC markers and did not express cytokeratin and hematopoietic stem cell markers and showed multilineage differentiation potential under specific culture conditions. DFCs exhibited higher proliferation and colony-forming unit-fibroblast efficiency than ABM-MSCs; rhBMP-2 induced DFCs to differentiate toward a cementoblast/osteoblast phenotype and ABM-MSCs to differentiate only toward a osteoblast phenotype; and rhBMP-2-induced DFCs exhibited higher osteogenic differentiation potential than ABM-MSCs. These cells adhered, grew, and produced extracellular matrix on nanohydroxyapatite/collagen/poly(l-lactide) (nHAC/PLA). During a 14-day culture on nHAC/PLA, the extracellular alkaline phosphatase (ALP) activity of DFCs decreased gradually and that of ABM-MSCs increased gradually; rhBMP-2 enhanced their extracellular ALP activity, intracellular osteocalcin (OCN), and osteopontin (OPN) protein expression; and DFCs exhibited higher extracellular ALP activity and intracellular OCN protein expression than ABM-MSCs. When implanted subcutaneously in severe combined immunodeficient mice for 3 months, DFCs+nHAC/PLA+rhBMP-2 obtained higher percentage of bone formation area, OCN, and cementum attachment protein expression and lower OPN expression than ABM-MSCs+nHAC/PLA+rhBMP-2. These results showed that DFCs possessed superior proliferation and osteogenic differentiation potential in vitro, and formed higher quantity and quality bones in vivo. It suggested that DFCs might exhibit a more sensitive responsiveness to rhBMP-2, so that DFCs enter a relatively mature stage of osteogenic differentiation earlier than ABM-MSCs after rhBMP-2 induction. The findings imply that these dental stem/progenitor cells are alternative sources for AB engineering in regenerative medicine, and developing dental tissue may provide better source for stem/progenitor cells.

Effectiveness of Chitosan Nanohydrogel as a Bone Regenerative Material in Intrabony Defects in Patients With Chronic Periodontitis: A Randomized Clinical Trial

Aim:

Different procedures have been attempted to regenerate intrabony defects in periodontitis but complete regeneration is still a herculean feat. Nanoparticles could prove to be advantageous because of their small size and increased surface area. The aim was to evaluate the effectiveness of a chitosan nanohydrogel as a periodontal regenerative material in the management of intrabony defects.

Materials and Methods:

Twenty patients within the age group of 30 to 60 years with intrabony defects >3 mm and clinical attachment levels >5 mm were selected. They were divided randomly into two groups: group-1, which received only open flap debridement with bone graft and acted as control, and group-2, which received open flap debridement, bone graft mixed with a chitosan nanohydrogel, and acted as the test site. Clinical and radiographic measurements were recorded at baseline, three months, and six months. Intragroup comparison was done using a paired t-test and intergroup comparison was done using an unpaired t-test with the statistical value set at P < .05.

Results:

Chitosan hydrogel incorporated bone grafts showed improved bone regenerative potential. The mean reduction in clinical attachment level in group-2 (8.7 ± 0.6 to 1.6 ± 0.8) was significantly higher than that of group-1 (8.6 ± 0.5 to 2.4 ± 0.7). The mean reduction in probing depths in group-2 (test group) was significantly higher (8.3 ± 0.9 to 1.6 ± 0.8) when compared to group-1 (8 ± 0.8 to 2.3 ± 0.7). Significant amount of defect fill was obtained in both the groups from baseline to six-month period.

Conclusion:

Organic materials such as chitosan could have potential bone regenerative capacity.

Characterization of Dental Pulp Stem Cell Responses to Functional Biomaterials Including Mineralized Trioxide Aggregates

INTRODUCTION

Many studies in stem cell biology have demonstrated that dental pulp stem cells (DPSC) may be highly proliferative and capable of pluripotent differentiation into many different tissue types. Recent advances in stem cell research have outlined methods for directing in vitro or in vivo growth, viability, and proliferation, as well as differentiation of DPSC-although much remains to be discovered. Based upon this information, the primary objective of this study was to understand the functional biomaterials needed to more effectively direct DPSC viability, growth, and proliferation.

METHODS

Using an approved protocol, previously collected and isolated samples of DPSC from an existing repository were used. Previously established stem cell biomarkers (Sox-2, Oct-4, NANOG) from each isolate were correlated with their proliferation rates or doubling times to categorize them into rapid, intermediate, or slow-dividing multipotent DPSC. Growth factors and other functional dental biomaterials were subsequently tested to evaluate DPSC responses in proliferation, viability, and morphology.

RESULTS

Differential responses were observed among DPSC isolates to growth factors, including vascular endothelial growth factor (VEGF) and bone morphogenic protein (BMP-2), and functional biomaterials such as mineralized trioxide aggregates (MTA). The responsiveness of DPSC isolates did not correlate with any single factor but rather with a combination of proliferation rate and biomarker expression.

CONCLUSIONS

These data strongly suggest that some, but not all, DPSC isolates are capable of a robust and significant in vitro response to differentiation stimuli, although this response is not universal. Although some biomarkers and phenotypes that distinguish and characterize these DPSC isolates may facilitate the ability to predict growth, viability, and differentiation potential, more research is needed to determine the other intrinsic and extrinsic factors that may contribute to and modulate these DPSC responses to these functional biomaterials for biotechnology and bioengineering applications.

Views on antioxidant mouthwashes as adjunct in periodontal therapy

Clinical decision is often difficult with chlorhexidine mouthwash. The use of antioxidant mouthwashes for the treatment of periodontal disease is in practise. Therefore, it is of interest to collect gleaned information on Antioxidant mouthwashes as periodontal therapy from known literature. Improvement in treatment using antioxidant mouthwashes is reported in several studies. The mouthwash with antioxidants has similar anti-gingivitis, antiplaque and antimicrobial effects as that of chlorhexidine mouthwash.

Transcriptome Analysis Reveals High Similarities between Adult Human Cardiac Stem Cells and Neural Crest-Derived Stem Cells

For the identification of a stem cell population, the comparison of transcriptome data enables the simultaneous analysis of tens of thousands of molecular markers and thus enables the precise distinction of even closely related populations. Here, we utilized global gene expression profiling to compare two adult human stem cell populations, namely neural crest-derived inferior turbinate stem cells (ITSCs) of the nasal cavity and human cardiac stem cells (hCSCs) from the heart auricle. We detected high similarities between the transcriptomes of both stem cell populations, particularly including a range of neural crest-associated genes. However, global gene expression likewise reflected differences between the stem cell populations with regard to their niches of origin. In a broader analysis, we further identified clear similarities between ITSCs, hCSCs and other adherent stem cell populations compared to non-adherent hematopoietic progenitor cells. In summary, our observations reveal high similarities between adult human cardiac stem cells and neural crest-derived stem cells from the nasal cavity, which include a shared relation to the neural crest. The analyses provided here may help to understand underlying molecular regulators determining differences between adult human stem cell populations.

Long non-coding RNA TUG1 participates in LPS-induced periodontitis by regulating miR-498/RORA pathway

AIM

This study was aimed to investigate the role of TUG1 in LPS-stimulated hPDLCs and to evaluate the potential functions of TUG1 in the pathogenesis of periodontitis.

METHODS

LPS-stimulated hPDLCs were established as the cell model. CCK-8 assay was performed to assess cell proliferation ability. Flow cytometry was performed to detect cell cycle distribution, and quantitative RT-PCR and Western blotting were conducted to measure gene expressions. ELISA kits were used to evaluate the production of inflammatory cytokines. The putative binding site between TUG1 and miR-498 was verified using luciferase reporter and RNA immunoprecipitation assays.

RESULTS

TUG1 was downregulated upon LPS stimulation in hPDLCs. TUG1 overexpression promoted cell proliferation through regulating the cell cycle distribution, along with the decreased expression of p21 and increased expression of CDK2 and cyclin D1. Besides, TUG1 overexpression decreased the production of inflammatory cytokines. The effects were opposite upon TUG1 knockdown. TUG1 negatively regulated its target miR-498, and influenced the expression of RORA, the direct target of miR-498. Simultaneous TUG1 overexpression and miR-498 reversed the effect of TUG1 overexpression alone on alleviating LPS-induced cell injury and inhibition of Wnt/β-catenin signaling, which was further changeover after co-overexpression with RORA.

CONCLUSION

Therefore, TUG1 could protect against periodontitis via regulating miR-498/RORA mediated Wnt/β-catenin signaling.

Human Oral Stem Cells, Biomaterials and Extracellular Vesicles: A Promising Tool in Bone Tissue Repair

Tissue engineering and/or regenerative medicine are fields of life science exploiting both engineering and biological fundamentals to originate new tissues and organs and to induce the regeneration of damaged or diseased tissues and organs. In particular, de novo bone tissue regeneration requires a mechanically competent osteo-conductive/inductive 3D biomaterial scaffold that guarantees the cell adhesion, proliferation, angiogenesis and differentiation into osteogenic lineage. Cellular components represent a key factor in tissue engineering and bone growth strategies take advantage from employment of mesenchymal stem cells (MSCs), an ideal cell source for tissue repair. Recently, the application of extracellular vesicles (EVs), isolated from stem cells, as cell-free therapy has emerged as a promising therapeutic strategy. This review aims at summarizing the recent and representative research on the bone tissue engineering field using a 3D scaffold enriched with human oral stem cells and their derivatives, EVs, as a promising therapeutic potential in the reconstructing of bone tissue defects.

circRNA CDR1as Regulated the Proliferation of Human Periodontal Ligament Stem Cells under a Lipopolysaccharide-Induced Inflammatory Condition

circRNA CDR1as (CDR1as) has been demonstrated to play important roles in a variety of inflammation-related diseases by acting as miRNA sponges. The present study is aimed at investigating the potential roles of CDR1as in the proliferation of human periodontal ligament stem cells (PDLSCs) under an inflammatory condition induced by Porphyromonas gingivalis-derived lipopolysaccharide (LPS). Human periodontal ligament cells (PDLCs) were isolated from periodontal ligament tissue, and PDLSCs were sorted from PDLCs based on the STRO-1 expression through fluorescence-activated cell sorting. We further found that CDR1as was significantly downregulated in LPS-treated PDLSCs compared to untreated cells, as well as in normal periodontal ligament tissues compared to periodontitis tissues. Knockdown of CDR1as promoted LPS-induced proliferative inhibition of PDLSCs, whereas overexpression of CDR1as alleviated the LPS-induced proliferative ability of PDLSCs. Mechanistically, CDR1as functioned as an miR-7 sponge to activate the ERK signal pathway to mediate the inhibition effect of LPS on cell proliferation. Taken together, our findings revealed the effects of the interacting pair of CDR1as/miR-7 on the proliferation ability of PDLSCs within their surrounding inflammatory microenvironment of periodontitis.

Human Dental Pulp Stem Cells Grown in Neurogenic Media Differentiate Into Endothelial Cells and Promote Neovasculogenesis in the Mouse Brain

Dental pulp stem cells (DPSCs) have the capacity to give rise to cells with neuronal-like phenotypes, suggesting their use in brain cell therapies. In the present work, we wanted to address the phenotypic fate of adult genetically unmodified human DPSCs cultured in Neurocult^TM (Stem Cell Technologies), a cell culture medium without serum which can be alternatively supplemented for the expansion and/or differentiation of adult neural stem cells (NSCs). Our results show that non-genetically modified human adult DPSCs cultured with Neurocult NS-A proliferation supplement generated neurosphere-like dentospheres expressing the NSC markers Nestin and glial fibrillary acidic protein (GFAP), but also the vascular endothelial cell marker CD31. Remarkably, 1 month after intracranial graft into athymic nude mice, human CD31+/CD146+ and Nestin+ DPSC-derived cells were found tightly associated with both the endothelial and pericyte layers of brain vasculature, forming full blood vessels of human origin which showed an increased laminin staining. These results are the first demonstration that DPSC-derived cells contributed to the generation of neovasculature within brain tissue, and that Neurocult and other related serum-free cell culture media may constitute a fast and efficient way to obtain endothelial cells from human DPSCs.

Recent advances in stem cells therapy: A focus on cancer, Parkinson's and Alzheimer's

Stem cells serve as potential therapeutics due to their high proliferative capacity, low immunogenic reactivity and their differentiating capabilities. Several pre-clinical and early-stage clinical studies are carried out to treat genetic diseases, cancers and neurodegenerative disorders with promising preliminary results. However, there are still many challenges that scientists are trying to overcome such as the unclear expression profile of stem cells in vivo, the homing of stem cells to the site of injury and their potential immune-reactivity. Prospective research lies in gene editing of autologous stem cells in vitro and safe injection of these modified cells back into patients. Here, we review the clinical trials executed using stem cell therapy in an attempt to cure challenging diseases like cancer, Parkinson's and Alzheimer's diseases.

Autologous dental pulp mesenchymal stem cells for inferior third molar post-extraction socket healing: A split-mouth randomised clinical trial

Background

Since the discovery of adult mesenchymal stem cells extensive research has been conducted to determine their mechanisms of differentiation and effectiveness in cell therapy and regenerative medicine.

Material and Methods

To assess the efficacy of autologous dental pulp mesenchymal stem cells delivered in a collagen matrix for post-extraction socket healing, a single-centre, double-blind, randomised, split-mouth, controlled clinical trial was performed. Both impacted mandibular third molars were extracted from 32 patients. Dental pulp was collected and dissociated; the resulting cell suspension, obtained by centrifugation, was incorporated into a resorbable collagen matrix and implanted in 32 experimental post-extraction sockets. Collagen matrices alone were implanted in 32 contralateral, control post-extraction sockets. Two neuroradiologists independently assessed the extent of bone repair at 6 months after the extractions. Computed tomography (CT, Philips Brilliance) and an advanced display platform (IntelliSpace Portal) was used to record extraction socket density, expressed as Hounsfield units (HU) and height (mm) of the distal interdental bone septum of the second molar. Measurements at 6 months post-extraction were compared with measurements obtained immediately after extraction. Data were analysed with the statistical program STATA 14.

Results

Two patients dropped out of the study. The final sample consisted of 22 women and 8 men (mean age, 23 years; range: 18–30 years). Clinical, radiological, and surgical characteristics of impacted third molars of the control and experimental groups were homogeneous. Measurements obtained by the two neuroradiologists showed agreement. No significant differences were found in the extent of bone repair during analyses of density (p=0.4203 neuroradiologist 1; p=0.2525 neuroradiologist 2) or interdental septum height (p=0.2280 neuroradiologist 1; p=0.4784 neuroradiologist 2).

Conclusions

In our clinical trial, we were unable to demonstrate that autologous dental pulp mesenchymal stem cells reduce socket bone resorption after inferior third molar extraction.

Key words:Clinical trial, autologous, pulpal stem cells, extraction socket healing.

Comparative differentiation analysis of distinct oral tissue-derived cells in response to osteogenic stimulation

BACKGROUND

Mixed cell populations from oral tissues may be superior to pure stem cells for regenerative approaches. Therefore, the aim of the present study was to explore the osteogenic potential of mixed cells derived from oral connective tissues compared to alveolar osteoblasts.

MATERIALS AND METHODS

Primary cells were isolated from the alveolar bone, periodontal ligament and gingiva. Following characterization by colony formation, growth capacity and flow cytometry, all cells were subjected to osteogenic differentiation induction and screened for a large panel of osteogenic markers using western blots, qPCR arrays, and matrix mineralization and alkaline phosphatase quantification.

RESULTS

Non-induced mixed cells from gingiva showed higher colony formation efficiency but decreased proliferation compared to non-induced periodontal mixed cells, while both entities revealed similar surface markers tested in this setup. Following osteogenic induction, all cell populations individually expressed receptors with distinctively activated downstream effectors. Gene expression of induced periodontal mixed cells was similar to alveolar osteoblasts, but was differently modulated in gingival mixed cells. The latter failed to achieve osteogenic differentiation in terms of matrix mineralization and alkaline phosphatase activity, which was well observed in periodontal mixed cells and osteoblasts.

CONCLUSION

Mixed cells from periodontal ligament but not from gingiva feature an inherent osteogenic capacity in vitro. From these results, it can be concluded that periodontal cells do not require further stem cell enrichment in order to qualify for bone regeneration.

CLINICAL RELEVANCE

Our data contribute to the development of novel cell-based therapies using mixed cells from the periodontal ligament in regenerative periodontics.

Applications of inflammation-derived gingival stem cells for testing the biocompatibility of dental restorative biomaterials

BACKGROUND

Normal or inflamed gingival tissues are regarded as a source of mesenchymal stem cells (MSCs) abundant and easily accessible through minimally invasive dental procedures. Due to the proximity of dental resin composites to gingival tissues and to the possible local cytotoxic effect of the eluted components, gingiva-derived MSCs could be used to investigate the biocompatibility of dental biomaterials.

PURPOSE

The present research aimed to isolate (MSCs) from inflamed and normal gingiva, to fully characterize them and to observe their behavior in relation with some commercial resin composite materials and one experimental material.

MATERIAL AND METHODS

Following their isolation, putative MSCs from both gingival sources were grown under the same culture conditions and characterized by immunophenotyping of cell surface antigens by flow-cytometry and transcription factors by immunocytochemical staining. Moreover, stemness gene expression was evaluated by RT-PCR analysis. Multipotent mesenchymal differentiation potential was investigated. Osteogenic and neurogenic differentiated cells were highlighted by immunocytochemical staining, chondrogenic cells by cytochemical staining, and adipocytes by cytochemical staining and spectrophotometry, respectively. Resin composite cytotoxicity was evaluated by cell membrane fluorescent labeling with PKH 26 and MTT assay. The results of PKH labeling were statistically analysed using two-way RM ANOVA with Bonferroni post-tests. For MTT assay, two-way RM ANOVA with Bonferroni post-tests and unpaired t test with Welch's correction were used.

RESULTS

A similar expression pattern of surface markers was observed. The cells were positive for CD105, CD73, CD90, CD49e, CD29, CD44 and CD166 and negative for CD45, CD34, CD14, CD79, HLA-DR and CD117 indicating a mesenchymal stem cell phenotype. The qRT-PCR analysis revealed a low gene expression for NOG, BMP4 and Oct3/4 and an increased expression for Nanog in both cells lines. Immunocytochemical analysis highlighted a more intense protein expression for Nanog, Oct3/4 and Sox-2 in MSCs derived from normal gingiva than from inflamed gingiva. Multipotent differentiation capacity of MSCs isolated from both sources was highlighted. The tested materials had no hazardous effect on MSCs as the two cell lines developed well onto resin composite substrates. Cell counting revealed some significant differences in the number of PKH-labeled MSCs at some experimental moments. Also, some differences in cell viability were recorded indicating better developmental conditions offered by some of the tested biomaterials.

CONCLUSIONS

The experimental resin composite behaved like the most biocompatible commercial material. Inflamed gingiva-derived MSCs retain their stem cell properties and could be used as a valuable cell line for testing dental biomaterials.

Stem-cell therapy and platelet-rich plasma in regenerative medicines: A review on pros and cons of the technologies

Regenerative medicine encompasses new emerging branch of medical sciences that involves the functional restoration of tissues or organs caused by severe injuries or chronic diseases. Currently, there are two contending technologies that can repair and restore the damaged tissues, namely platelet-rich plasma (PRP)- and stem cell (SC)-based therapies. PRP is a component of blood that contains platelet concentrations above the normal level and includes platelet-related growth factors and plasma-derived fibrinogen. Platelets are the frontline healing response to injuries as they release growth factors for tissue repair. SCs, on the other hand, are the unspecialized, undifferentiated, immature cells that based on specific stimuli can divide and differentiate into specific type of cells and tissues. Differentiated SCs can divide and replace the worn out or damaged tissues to become tissue- or organ-specific cells with specialized functions. Despite these differences, both approaches rely on rejuvenating the damaged tissue. This review is focused on delineating the preparation procedures, similarities and disparities and advantages and disadvantages of PRP- and SC-based therapies.