Photobiomodulation and low-intensity pulsed ultrasound synergistically enhance dental mesenchymal stem cells viability, migration and differentiation: an invitro study

Novel methods and technologies that improve mesenchymal stem cells (MSCs) proliferation and differentiation properties are required to increase their clinical efficacy. Photobiomodulation (PBM) and low-intensity pulsed ultrasound (LIPUS) are two strategies that can be used to enhance the regenerative properties of dental MSCs. This study evaluated the cytocompatibility and osteo/odontogenic differentiation of dental pulp, periodontal ligament, and gingival MSCs after stimulation by either PBM or LIPUS and their combined effect. MTT assay, cell migration assay, osteo/odontogenic differentiation by AR staining and ALP activity, and expression of osteo/odontogenic markers (OPG, OC, RUNX2, DSPP, DMP1) by RT-qPCR were evaluated. Statistical analysis was performed using ANOVA, followed by Tukey's post hoc test, with a p-value of less than 0.05 considered significant. The results showed that combined stimulation by PBM and LIPUS resulted in significantly the highest viability of MSCs, the fastest migration, the most dense AR staining, the most increased ALP activity, and the most elevated levels of osteogenic and odontogenic markers. The synergetic stimulation of PBM and LIPUS can be utilized in cell-based regenerative approaches to promote the properties of dental MSCs.

Comparison of aquaporin profile of advanced passage mesenchymal stem cells with early passage mesenchymal stem cells and determination of its effect on adipogenic differentiation efficiency

OBJECTIVE

Our study aimed to compare aquaporin profiles in advanced and early passage bone marrow-derived mesenchymal stem cells (BM-MSCs) and assess the impact of aquaporin changes after adipogenic differentiation. Aquaporins are crucial for stem cell survival and differentiation during their life cycle. We focused on the role of aquaporins in the cell structures of advanced and early passage stem cells.

METHODS

In our study, BM-MSCs were used for our objectives. Characterization of the cells was evaluated via flow cytometry using stem cell surface markers. The characterized BM-MSCs were divided into control and differentiation groups at passages 3 (P3) and 8 (P8). AQP1, AQP3, AQP7, AQP9, and AQP10 expression levels on days 0, 1, 3, 7, 14, and 21 were evaluated using Real Time-PCR, ELISA, and immunofluorescence studies.

RESULTS

The cells were characterized by flow cytometry and confirmed to exhibit BM-MSC characteristics. At P3 and P8, differentiation was initiated, and AQP protein expression was observed to initially increase and then decrease on subsequent days. The increase in AQP protein expression at P3 occurred earlier than that at P8. Gene expression analysis demonstrated a statistically significant increase in AQP gene expression on days when AQP protein expression decreased. Moreover, statistical differences were observed between late and early passage AQP profiles.

CONCLUSION

Our study examined the composition of AQPs in BM-MSCs in association with cell passage, and found that AQPs play a role in the differentiation process. The connection between the AQP profile and aging might be related to differentiation capacity, which could have implications for slowing down cellular aging and developing new therapeutic approaches.

Platelet Power: Revitalizing Endodontics With Scaffolds

This article provides an overview of a biologically based method for restoring damaged tooth structures and pulp tissues known as regenerative endodontics. It explores the concept of regenerative endodontics, its tissue engineering approach, and its application in maintaining vitality. The article discusses the significance of the factors affecting growth, scaffolds, and stem cells being the three tissue engineering components involved in the regeneration of pulp tissues. It also delves into the classification of scaffolds and the role of platelet-rich fibrin (PRF) and platelet-rich plasma (PRP) as biological scaffolds. The methodology section details the search process for relevant studies, and the review section presents research findings associated with PRF and its application in regeneration and repair of tissue. The article concludes by highlighting the potential of advanced PRF and injectable PRF in regenerative endodontics, with a focus on their impact on tissue regeneration and healing.

Does the use of different scaffolds have an impact on the therapeutic efficacy of regenerative endodontic procedures? A systematic evaluation and meta-analysis

BACKGROUND

In the regenerative endodontic procedures, scaffolds could influence the prognosis of affected teeth. Currently, there is controversy regarding the postoperative evaluation of various scaffolds for pulp regeneration. The objective of this study was to access whether other scaffolds, used alone or in combination with blood clot (BC), are more effective than BC in regenerative endodontic procedures.

METHODS

We systematically search the PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL), Embase, and Google Scholar databases. Randomized controlled trials examining the use of BC and other scaffold materials in the regenerative endodontic procedures were included. A random effects model was used for the meta-analysis. The GRADE method was used to determine the quality of the evidence.

RESULTS

We screened 168 RCTs related to young permanent tooth pulp necrosis through electronic and manual retrieval. A total of 28 RCTs were related to regenerative endodontic procedures. Ultimately, 12 articles met the inclusion criteria and were included in the relevant meta-analysis. Only 2 studies were assessed to have a low risk of bias. High quality evidence indicated that there was no statistically significant difference in the success rate between the two groups (RR=0.99, 95% CI=0.96 to 1.03; 434 participants, 12 studies); low-quality evidence indicated that there was no statistically significant difference in the increase in root length or root canal wall thickness between the two groups. Medium quality evidence indicated that there was no statistically significant difference in pulp vitality testing between the two groups.

CONCLUSIONS

For clinical regenerative endodontic procedures, the most commonly used scaffolds include BC, PRP, and PRF. All the different scaffolds had fairly high clinical success rates, and the difference was not significant. For regenerative endodontic procedures involving young permanent teeth with pulp necrosis, clinical practitioners could choose a reasonable scaffold considering the conditions of the equipment and patients.

Clinical, Radiographic, and Histologic Outcomes of Regenerative Endodontic Treatment in Human Immature Teeth Using Different Biological Scaffolds: A Systematic Review and Meta-analysis

BACKGROUND

Biological scaffolds such as blood clot (BC), platelet-rich plasma (PRP), platelet- rich fibrin (PRF), and platelet pellet (PP) are used in regenerative endodontic treatments (RETs).

OBJECTIVE

To systematically and quantitatively evaluate clinical, radiographic, and histologic outcomes of RET studies using different biological scaffolds.

METHODS

MEDLINE, Scopus, Cochrane library, and Embase were searched to identify studies on RET procedures with any scaffold type performed on immature non-vital human teeth, employing any type of biological scaffold. Clinical, radiographic, and histologic outcomes were extracted. Cochrane collaboration risk of bias tool and Newcastle-Ottawa scale were used for quality assessment. Random and fixed model meta-analysis was carried out with 95% confidence interval.

RESULTS

Thirty-two studies were included in the qualitative analysis from the primarily retrieved 1895 studies. Only one study had high risk of bias and 71.8% of the studies had high quality. None of the studies reported any histologic findings. Thirty studies were included in meta-analysis. Clinical success rate of RET using either BC, PRP, or PRF was >99%. Furthermore, 32%, 23%, and 27% of BC, PRP, and PRF cases regained vitality, respectively. Periapical healing was seen in 67%, 75%, and 100% of BC, PRP, and PRF cases, respectively. There was no statistical difference between BC, PRP, or PRF regarding clinical success or any radiographic outcomes.

CONCLUSION

There was no significant difference between BC, PRP, and PRF in terms of clinical and radiographic outcomes. When it is difficult or dangerous to induce bleeding in root canals, PRP and PRF may be employed instead.

Effect of rapamycin on human periodontal ligament stem cells that have been exposed to sodium hypochlorite

AIMS

The present study investigated the effect of rapamycin on the viability and osteogenic differentiation potential of human periodontal ligament stem cells (hPDLSCs) in the presence of sodium hypochlorite (NaOCl).

MAIN METHODS

After determining the minimum inhibitory concentration of NaOCl and optimum concentration of rapamycin, the viability of hPDLSCs was evaluated using the MTT assay subsequent to their exposure to NaOCl, rapamycin, or a combination of both. Osteogenic differentiation was evaluated by the cell mineralization assay performed by alizarin red S staining, alkaline phosphatase activity, and monitoring the expression of osteogenic genes markers Runt-related transcription factor 2, osteocalcin, and osteoprotegerin, using real-time quantitative polymerase chain reaction (RT-qPCR). The expression of autophagy-related genes PI3K, Akt, and mTOR, was also analyzed with RT-qPCR.

KEY FINDINGS

Stem cells treated with rapamycin showed the highest percentage of viable cells in the presence of NaOCl. The same trend was observed for all osteogenic differentiation assays. The hPDLSCs treated with rapamycin demonstrated the highest calcium nodule deposition, alkaline phosphatase activity, and the expression of osteogenic gene markers. These effects were not adversely affected by the presence of NaOCl. Rapamycin significantly inhibited mTOR gene expression, while there were no differences in the gene expression of PI3K and Akt.

SIGNIFICANCE

Rapamycin counteracts the cytotoxic effect of NaOCl by enhancing the viability and osteogenic differentiation potential of hPDLSCs. Rapamycin appears to accomplish these processes via autophagy activation, by inhibiting mTOR gene expression. The incorporation of rapamycin in regenerative endodontic therapy may encourage a higher success rate.

Influence of Ascorbic Acid as a Growth and Differentiation Factor on Dental Stem Cells Used in Regenerative Endodontic Therapies

BACKGROUND

Vitamin C is one of the major extracellular nonenzymatic antioxidants involved in the biosynthesis of collagen. It promotes the growth of fibroblasts, wound healing processes, and enhances the survival and differentiation of osteoblasts. The potential effects of ascorbic acid on human dental pulp cells (DPC) and the cells of the apical papilla (CAP) used in actual regenerative endodontic procedures remain largely unknown. In this study, we investigated the possible employment of ascorbic acid in the differentiation and regenerative therapies of DPC and CAP.

METHODS

Nine extracted human wisdom teeth were selected for this study. Subpopulations of stem cells within DPC and CAP were sorted with the mesenchymal stem cell marker STRO-1, followed by treatments with different concentrations (0 mM, 0.1 mM, 0.5 mM, and 1.0 mM) of ascorbic acid (AA), RT-PCR, and Western blot analysis.

RESULTS

FACS analysis revealed the presence of cell subpopulations characterized by a strong expression of mesenchymal stem cell marker STRO-1 and dental stem cell markers CD105, CD44, CD146, CD90, and CD29. Treatment of the cells with defined amounts of AA revealed a markedly increased expression of proliferation marker Ki-67, especially in the concentration range between 0.1 mM and 0.5 mM. Further investigations demonstrated that treatment with AA led to significantly increased expression of common stem cell markers OCT4, Nanog, and Sox2. The most potent proliferative and expressional effects of AA were observed in the concentration of 0.1 mM.

CONCLUSIONS

AA might be a novel and potent growth promoter of human dental cells. Increasing the properties of human dental pulp cells and the cells of the apical papilla using AA could be a useful factor for further clinical developments of regenerative endodontic procedures.

Effect of amniotic membrane and platelet-rich fibrin membrane on bone healing post endodontic surgery: An ultrasonographic, randomized controlled study

The use of membrane barriers and bone grafting materials in endodontic surgery promotes healing by regeneration rather than repair by scar tissue. Due to its valuable regenerative and therapeutic properties, the human amniotic membrane can support ideal periapical rehabilitation and promote better healing after surgery. The current trial aimed to evaluate the amniotic membrane's healing potential and compare it with platelet-rich fibrin using color doppler sonography. The current study is a randomized, double-blinded, parallel-group, single-center study. Thirty-four systematically healthy individuals requiring endodontic surgery who fulfilled all inclusion and exclusion criteria were selected and randomly placed in two groups. Surgical curettage of the bony lesion was performed and filled with hydroxyapatite graft. Amniotic membrane (Group 1) and platelet-rich fibrin (Group 2) were placed over the bony crypt, and the flap was sutured back. The lesion's surface area and vascularity were the parameters assessed with ultrasound and color doppler. and observations: The groups found a significant difference in mean vascularity at 1 month and mean vascularity change from baseline to 1 month (p < 0.05). Mean surface area had no statistically significant difference between the groups. However, in terms of the percentage change in surface area, a significant difference was found from baseline to 6 months (p < 0.05). Amniotic membrane was a significantly better promoter of angiogenesis than platelet-rich fibrin in the current trial. The osteogenic potential of both materials was similar. However, the clinical application, availability, and cost-effectiveness of amniotic membrane support it as a promising therapeutic alternative in clinical translation. Further large-scale trials and histologic studies are warranted.

Clinical Outcome and Comparison of Regenerative and Apexification Intervention in Young Immature Necrotic Teeth-A Systematic Review and Meta-Analysis

This systematic review aimed to evaluate interventions individually and compare the clinical outcome of young, immature teeth treated with regenerative endodontic therapy (RET) and apexification procedure. The protocol was registered with PROSPERO (International Prospective Register of Systematic Reviews), bearing the registration number CRD42021230284. A bibliographic search in the biomedical databases was conducted in four databases—PubMed, CENTRAL, EMBASE and ProQuest—using searching keywords and was limited to studies published between January 2000 and April 2022 in English. The search was supplemented by manual searching, citation screening and scanning of all reference lists of selected paper. The study selection criteria were randomized clinical trial, prospective clinical studies and observational studies. The search found 32 eligible articles, which were included in the study. The quality assessment of the studies was performed using the Cochrane risk of bias tool for randomized control trials and non-randomized clinical studies. The meta-analysis was performed using Review Manager software (REVMAN, version 5). The results indicated that a clinicians’ MTA apexification procedure was more successful compared to calcium hydroxide. In RET, apical closure and overall success rate is statistically same for both apical platelet concentrates (APCs) and blood clots (BC). Both interventions have similar survival rates; however, RET should be preferred in cases where the root development is severely deficient, there is insufficient dentine and the tooth’s prognosis is hopeless even with an apexification procedure.

Evaluation of the Treatment Protocols in the Management of Pulpally Involved Young Permanent Teeth in Children: A Systematic Review and Meta-analysis

Background

In children with young permanent teeth, dental caries and traumatic injuries are the most common problems leading to pulp necrosis. Since, root development is completed in two to three years after eruption of the tooth into the oral cavity, loss of pulp vitality in young permanent tooth creates distinctive problems. In spite of exceeding availability of treatment procedures there is a need to search for a substantial procedure to treat young permanent teeth effectively.

Aim

The aim of this systematic review was to evaluate the treatment protocols in the management of pulpally involved young permanent teeth in children.

Method

Systematic search was conducted on databases PubMed, Cochrane, and Google Scholar among studies published from 1st January 2010 till 31st May 2020. Studies meeting the inclusion criteria were included in the review and were then assessed for quality with the help of predetermined criteria which categorized studies into high, medium, and low.

Results

Search strategy yielded 4,846 articles. After screening through titles and abstracts, 33 articles remained which were further screened for full text. At the end, 14 articles were included in systematic review. Furthermore, the included articles were statistically evaluated by meta-analysis.

Conclusion

In apexogenesis and apexification procedures, newer biomimetic materials like mineral trioxide aggregate and biodentine have more success rate than conventionally used calcium hydroxide. Among regenerative endodontic procedures platelet-rich plasma and platelet- rich fibrin showed better results.

Clinical significance

To amend clinician perceptions towards acceptance of the newer regenerative procedures and their effectiveness in management of young permanent tooth.

How to cite this article

Saxena N, Hugar SM, Soneta SP, et al. Evaluation of the Treatment Protocols in the Management of Pulpally Involved Young Permanent Teeth in Children: A Systematic Review and Meta-analysis. Int J Clin Pediatr Dent 2022;15(S-1):S103–S113.

Different Approaches to the Regeneration of Dental Tissues in Regenerative Endodontics

(1) Background: The regenerative procedure has established a new approach to root canal therapy, to preserve the vital pulp of the tooth. This present review aimed to describe and sum up the different approaches to regenerative endodontic treatment conducted in the last 10 years; (2) Methods: A literature search was performed in the PubMed and Cochrane Library electronic databases, supplemented by a manual search. The search strategy included the following terms: “regenerative endodontic protocol”, “regenerative endodontic treatment”, and “regenerative endodontics” combined with “pulp revascularization”. Only studies on humans, published in the last 10 years and written in English were included; (3) Results: Three hundred and eighty-six potentially significant articles were identified. After exclusion of duplicates, and meticulous analysis, 36 case reports were selected; (4) Conclusions: The pulp revascularization procedure may bring a favorable outcome, however, the prognosis of regenerative endodontics (RET) is unpredictable. Permanent immature teeth showed greater potential for positive outcomes after the regenerative procedure. Further controlled clinical studies are required to fully understand the process of the dentin–pulp complex regeneration, and the predictability of the procedure.

Vital Pulp Therapy an Insight Over the Available Literature and Future Expectations

Vital pulp therapy (VPT) defined as “treatment which aims at preserving and maintaining the pulp tissue that has been compromised but not destroyed by extensive dental caries, dental trauma, and restorative procedures or for iatrogenic reasons”, offers some beneficial advantages over the conventional root canal treatment such as protective resistance for mastication forces or to prevent the loss of environmental changes sensation ability, which can lead to unnoticeable progression of caries and later fracture. A wide range of materials are suggested in the literature to be used as pulp capping protective dressing materials that varies from ready-made synthetic materials to biological based scaffolds and composites. The aim of the present review is to provide a full understanding of currently used materials to clinicians in order to help in their decision-making process delivering the best available evidence-based treatments to their patients. An extensive search for recent available data regarding direct pulp capping materials and potential suggestions for future use have been made. Newly developed biological based scaffolds showed promising results in dentine regeneration therefore strengthening the tooth structure and overcoming potential drawbacks of use of currently available recommended materials.

Knowledge, attitude, and practice toward regenerative endodontics and factors affecting its practice among dental practitioners in Ajmer city: A cross-sectional study

Background

Regenerative methods, which regenerate the damaged structures, are one of the treatment methods in endodntics. This conservative approach helps to generate cells that may produce the lost structure. Thus, the aim of this study was to explore the knowledge, attitude, and practice among dental practitioners toward regenerative endodontics and factors affecting their knowledge, attitude, and practice.

Materials and Methods

It was a cross-sectional questionnaire study conducted in the month of June-August 2018 in Ajmer city. Permission to conduct the study was obtained from JLN Medical College and Hospital, Department of Dentistry. A total of 100 clinics were visited and face-to-face interview schedule was conducted. A total of 123 dental practitioners were interviewed. A 26 item questionnaire was generated to measure knowledge, attitude, and practice of dental professionals regarding regenerative endodontics.

Results

63% of study participants had poor knowledge scores. Majority of study participants 83 (67%) had poor attitude scores. On applying Pearson's correlation, it was determined that the knowledge regarding regenerative endodontics was significantly (P ≤ 0.001) ** correlated to the attitude among study participants. On applying Chi-square test, it was assessed that the knowledge and practice among study participants were significantly (P = 0.041*) and (P = 0.001**) associated with gender of study participants.

Conclusion

From above results, it is concluded that study participants have poor knowledge, attitude, and practice regarding regenerative endodontics. The knowledge regarding regenerative endodontics was significantly associated with the attitude of study participants. Participants with Masters of Dental Surgery (MDS) degree had a significant effect on the knowledge regarding the regenerative endodontics. Endodontic specialty has a significant effect on the attitude of study subjects.

Differentiation of dental pulp stem cells into neuron-like cells

Background and objectives: With regard to their ease of harvest and common developmental origin, dental pulp stem cells (DPSCs) may act as a favorable source of stem cells in generation of nerves. Moreover; cellular migration and differentiation as well as survival, self-renewal, and proliferation of neuroprogenitor species require the presence of the central nervous system (CNS) mitogens including EGF and bFGF. Accordingly, the possibility of the induction of neuronal differentiation of DPSCs by EGF and bFGF was evaluated in the present study.Materials and methods: DPSCs were treated with 20 ng/ml EGF, 20 ng/ml bFGF, and 10 µg/ml heparin. In order to further induce the neuroprogenitor differentiation, DPSC-derived spheres were also incubated in serum-free media for three days. The resulting spheres were then cultured in high-glucose Dulbecco's Modified Eagle Medium (DMEM) with 10% FBS. The morphology of the cells and the expression of the differentiation markers were correspondingly analyzed by quantitative polymerase chain reaction (qPCR), western blotting, and immunofluorescence (IF).Results: The EGF/bFGF-treated DPSCs showed significant increase in the expression of the neuroprogenitor markers of Nestin and SRY (sex determining region Y)-box 2 (SOX2), 72 h after treatment. The up-regulation of Nestin and SOX2 induced by growth factors was confirmed using western blotting and IF. The cultures also yielded some neuron-like cells with a significant rise in Nestin, microtubule-associated protein 2 (MAP2), and Neurogenin 1 (Ngn1) transcript levels; compared with cells maintained in the control media (p < 0.05).Conclusion: DPSCs seemed to potentially differentiate into neuron-like cells under the herein-mentioned treatment conditions.

Concerns of a Pediatric Dentist in Dental Stem Cells: An Overview

Stem cell biology has become an essential part of regenerative medicine and dentistry. The fact of availability of these stem cells among various dental tissues has doubled the researcher’s enthusiasm in the recent years due to fewer ethical constraints and minimally invasive nature. Stem cells from deciduous tooth among the dental stem cells are the ones obtained with least or no trauma. To date, enormous research has been reported on dental stem cells. The purpose of this review is to focus only on certain aspects of dental stem cells that are important to the specialty of pedodontics. Thus, a detailed emphasis is given on stem cells obtained from human deciduous teeth including their harvesting and storage techniques.

Histologic tissue response to furcation perforation repair using mineral trioxide aggregate or dental pulp stem cells loaded onto treated dentin matrix or tricalcium phosphate

Objectives

The aim of this study is to compare the effect of treated dentine matrix (TDM) and tricalcium phosphate (TCP) scaffolds on odontogenic differentiation and mineralization of dental pulp stem cells (DPSCs) in furcation perforations created in the pulp chamber floor of premolar teeth in dogs.

Material and methods

DPSCs were isolated and cultured from the dental pulp of the maxillary left second and third premolars of dogs. The DPSCs were loaded on TCP (SC+TCP) and TDM (SC+TDM) scaffolds and inserted into intentionally perforated pulp chamber floors of premolars in dogs; six teeth were used for each group. Three more groups of six specimens were created, and mineral trioxide aggregate (MTA), TDM, and TCP were inserted into the perforations to act as controls. An intact premolar and no treatment in the perforation site were used as positive and negative controls respectively. After 3 months, the animals were sacrificed and the type of inflammation, presence of dentine, continuation and type of cementum, type of connective tissue, and presence of foreign body reaction were evaluated, and significant differences were between groups determined using the Fisher’s exact test. The evaluation of the amount of inflammation and the percentage of new bone formation was evaluated using the Mann-Whitney U test.

Results

The negative control group was associated with severe inflammation and granulation tissue formation. In the positive control group, intact periodontal tissues and no inflammation were observed. Dentine bridge formation was not seen in specimens of any group. The specimens in the SC+TDM group were associated with significantly more bone formation than other groups (P < 0.001). The amount of inflammation was less than 10 % in specimens of all groups with the exception of three specimens in the TCP group that were categorized as 10–30 %. Chronic inflammation without foreign body reactions was the major pattern of inflammation in groups. Formation of cementum with a cellular and continuous appearance was seen in all specimens.

Conclusions

SC+TDM was associated with significantly more bone formation when used to repair uninfected furcation perforations in the premolar teeth of dogs.

Clinical relevance

Application of TDM as a biological scaffold in combination with DPSCs may offer an advantage during the repair of root perforation defects.

Transforming growth factor-β3 promotes facial nerve injury repair in rabbits

The present study investigated the effects of transforming growth factor (TGF)-β3 on the regeneration of facial nerves in rabbits. A total of 20 adult rabbits were randomly divided into three equal groups: Normal control (n=10), surgical control (n=10) and TGF-β3 treatment (n=10). The total number and diameter of the regenerated nerve fibers was significantly increased in the TGF-β3 treatment group, as compared with in the surgical control group (P<0.01). Furthermore, in the TGF-β3 treatment group, the epineurial repair of the facial nerves was intact and the nerve fibers, which were arranged in neat rows, were morphologically intact with visible myelin swelling. However, in the surgical control group, the epineurial repair was incomplete, as demonstrated by: Atrophic nerve fibers, partially disappeared axons and myelin of uneven thickness with fuzzy borders. Electron microscopy demonstrated that the regenerated fibers in the TGF-β3 treatment group were predominantly myelinated, with clear-layered myelin sheath structures and axoplasms rich in organelles. Although typical layered myelin sheath structures were observed in the surgical control group, the myelin sheaths of the myelinated nerve fibers were poorly developed and few organelles were detected in the axoplasms. Neuro-electrophysiological examination demonstrated that, as compared with the surgical control group, the latency period of the action potentials in the TGF-β3 treatment group were shorter, whereas the stimulus amplitudes of the action potentials were significantly increased (P<0.01). The results of the present study suggest that TGF-β3 may improve the regeneration of facial nerves following trauma or injury.

Scaffolds in regenerative endodontics: A review

Root canal therapy has enabled us to save numerous teeth over the years. The most desired outcome of endodontic treatment would be when diseased or nonvital pulp is replaced with healthy pulp tissue that would revitalize the teeth through regenerative endodontics. ‘A search was conducted using the Pubmed and MEDLINE databases for articles with the criteria ‘Platelet rich plasma’, ‘Platelet rich fibrin’, ‘Stem cells’, ‘Natural and artificial scaffolds’ from 1982–2015’. Tissues are organized as three-dimensional structures, and appropriate scaffolding is necessary to provide a spatially correct position of cell location and regulate differentiation, proliferation, or metabolism of the stem cells. Extracellular matrix molecules control the differentiation of stem cells, and an appropriate scaffold might selectively bind and localize cells, contain growth factors, and undergo biodegradation over time. Different scaffolds facilitate the regeneration of different tissues. To ensure a successful regenerative procedure, it is essential to have a thorough and precise knowledge about the suitable scaffold for the required tissue. This article gives a review on the different scaffolds providing an insight into the new developmental approaches on the horizon.

Expression of the IGF-1, IGFBP-3 and IGF-1 receptors in dental pulp stem cells and impacted third molars

IGF-1 regulates the metabolism of hard dental tissue through binding to the IGF-1 receptor on target cells. Furthermore, IGF-binding-protein-3 promotes the accessibility of IGF-1. The aim of this study was to investigate the expression of IGF-1, IGFBP-3 and IGF-1R in STRO-1-positive dental pulp stem cells (DPSCs) and fully impacted wisdom teeth in relation to tooth development. Third molars were surgically removed from 60 patients and classified into two groups: teeth showing ongoing development (group 1) and teeth that had completed root shaping (group 2). The transcript and protein levels of IGF-1, IGFBP-3 and IGF-1R were investigated using RT-PCR and immunohistochemistry. The expression of the same proteins was also analyzed in DPSCs. The teeth from group 1 showed significantly stronger expression of IGF-1 and IGF-1R. The major sources of all of the proteins investigated immunohistochemically in sections of wisdom teeth were odontoblasts, cementoblasts and cell colonies in the pulpal mesenchyme. These colonies were identified as stem cells in view of their positivity for STRO-1, and the cells were subsequently sorted by flow cytometry. These DPSCs demonstrated high levels of pluripotency markers and IGF-1 and IGF-1R. We conclude that members of the IGF-1 family are involved in the late stage of tooth development and the process of pulpal differentiation.

Effect of different calcium phosphate scaffold ratios on odontogenic differentiation of human dental pulp cells

Calcium phosphate (CaP) scaffolds have been widely and successfully used with osteoblast cells for bone tissue regeneration. However, it is necessary to investigate the effects of these scaffolds on odontoblast cells' proliferation and differentiation for dentin tissue regeneration. In this study, three different hydroxyapatite (HA) to beta tricalcium phosphate (β-TCP) ratios of biphasic calcium phosphate (BCP) scaffolds, BCP20, BCP50, and BCP80, with a mean pore size of 300μm and 65% porosity were prepared from phosphoric acid (H2PO4) and calcium carbonate (CaCO3) sintered at 1000°C for 2h. The extracts of these scaffolds were assessed with regard to cell viability and differentiation of odontoblasts. The high alkalinity, more calcium, and phosphate ions released that were exhibited by BCP20 decreased the viability of human dental pulp cells (HDPCs) as compared to BCP50 and BCP80. However, the cells cultured with BCP20 extract expressed high alkaline phosphatase activity and high expression level of bone sialoprotein (BSP), dental matrix protein-1 (DMP-1), and dentin sialophosphoprotein (DSPP) genes as compared to that cultured with BCP50 and BCP80 extracts. The results highlighted the effect of different scaffold ratios on the cell microenvironment and demonstrated that BCP20 scaffold can support HDPC differentiation for dentin tissue regeneration.

Imperative role of dental pulp stem cells in regenerative therapies: a systematic review

Stem cells are primitive cells that can differentiate and regenerate organs in different parts of the body such as heart, bones, muscles and nervous system. This has been a field of great clinical interest with immense possibilities of using the stem cells in regeneration of human organ those are damaged due to disease, developmental defects and accident. The knowledge of stem cell technology is increasing quickly in all medical specialties and in dental field too. Stem cells of dental origin appears to hold the key to various cell-based therapies in regenerative medicine, but most avenues are in experimental stages and many procedures are undergoing standardization and validation. Long-term preservation of SHED cells or DPSC is becoming a popular consideration, similar to the banking of umbilical cord blood. Dental pulp stem cells (DPSCs) are the adult multipotent cells that reside in the cell rich zone of the dental pulp. The multipotent nature of these DPSCs may be utilized in both dental and medical applications. A systematic review of the literature was performed using various internet based search engines (PubMed, Medline Plus, Cochrane, Medknow, Ebsco, Science Direct, Hinari, WebMD, IndMed, Embase) using keywords like “dental pulp stem cells”, “regeneration”, “medical applications”, “tissue engineering”. DPSCs appears to be a promising innovation for the re-growth of tissues however, long term clinical studies need to be carried out that could establish some authentic guidelines in this perspective.

A survey of attitude and opinions of endodontic residents towards regenerative endodontics

Aim:

The objective of this survey was to study the level of awareness, current state of knowledge and opinions towards regenerative endodontic treatments amongst the endodontic residents of India.

Settings and Design:

Questionnaire based survey was designed.

Materials and Methods:

After approval from the organizing committee of 26^th Federation of Operative Dentistry of India and 19^th Indian Endodontic Society National conference 2011, 200 copies of the questionnaire were circulated amongst the endodontic residents in conservative dentistry and endodontics at various colleges across the country about regenerative endodontic procedures. The survey included profile of the respondents and consisted of 23 questions about their knowledge, attitude and opinions regarding use of these procedures as part of future dental treatment.

Results:

The survey showed that half the participants (50.6%) had received continued education in stem cells and/or regenerative dental treatments. The majority of participants were of the opinion (86.6%) that regenerative therapy should be incorporated into dentistry, and most of them (88%) were willing to acquire training in learning this new treatment strategy. The results indicated that half of the participants (52.6%) were already using some type of regenerative therapy in their clinical practice; however, with a majority of these limited to use of membranes, scaffolds or bioactive materials.

Conclusions:

These results reflect that endodontic residents are optimistic about the use of regenerative endodontic procedures; however, a need for more research and training was felt.

Transplantation of undifferentiated and induced human exfoliated deciduous teeth-derived stem cells promote functional recovery of rat spinal cord contusion injury model

Regarding both the neural crest origin and neuronal potential of stem cells from human exfoliated deciduous teeth (SHED), here, we assessed their potential in addition to neural induced SHED (iSHED) for functional recovery when transplanted in a rat model for acute contused spinal cord injury (SCI). Following transplantation, a significant functional recovery was observed in both groups relative to the vehicle and control groups as determined by the open field locomotor functional test. We also observed that animals that received iSHED were in a better state as compared with the SHED group. Immunohistofluorescence evaluation 5 weeks after transplantation showed neuronal and glial differentiation and limited proliferation in both groups. However, myelin basic protein and chondroitin sulfate proteoglycan NG2-oligodendrocyte markers-were increased and glial fibrillary acidic protein-astrocyte marker-was decreased in the iSHED group in comparison with the SHED group. These findings have demonstrated that transplantation of SHED or its derivatives could be a suitable candidate for the treatment of SCI as well as other neuronal degenerative diseases.

Comparison of the proliferation, viability, and differentiation capacity of adipose-derived stem cells from different anatomic sites in rabbits

Tissue engineering is clinically promising for missing and damaged tissues. Adipose-derived stem cells (ASCs), a type of mesenchymal stem cells, represent a reliable source of seed cells for tissue engineering with multiple merits such as minimal invasion, abundant yield, little immunity, low morbidity, easy isolation, and rapid expansion. However, because the properties of adipose tissue-derived cells differ depending on the fat depot from which they are derived, we compared the ASCs from three anatomic sites of New Zealand white rabbits: subcutaneous inguinal (SI), subcutaneous dorsocervical (SD), and retroperitoneal perinephric (RP) regions. We investigated cellular behaviors including proliferation, viability, and differentiation. The ASCs of the subcutaneous regions (SI and SD) had higher performances in all assessments compared to those of the RP region. Moreover, the SI and SD ASCs had significant differences, with SI ASCs having better properties than SD ASCs. We conclude that the different anatomic distributions of fat contribute to the different behaviors of ASCs. The SI region offers the most applicable cell source reservoir for ASC tissue engineering.

Mesenchymal stem cells derived from dental tissues

Regeneration of tissues occurs naturally due to the existence of stem cells with the capacity to self-regenerate and differentiate; however, regenerative capacity decreases with age, and in many cases, regeneration is not sufficient to repair the damage produced by degenerative, ischaemic, inflammatory, or tumour-based diseases. In the last decade, advances have been made in the understanding of stem cells, the genes that control the alternative fates of quiescence and differentiation, and the niches that provide specific signals that modulate cell fate decisions. Embryonic stem-cell research is shedding light on the secrets of development. Adult stem cells (AS cells) are available from several sources. Bone marrow and connective tissue have been used in preliminary clinical trials for regenerative therapy. Recently, several types of AS cells have been isolated from teeth, including dental pulp stem cells, stem cells from human exfoliated deciduous teeth, periodontal ligament stem cells, dental follicle progenitor stem cells and stem cells from apical papilla. Preliminary data suggest that these cells have the capacity to differentiate into osteoblasts, adipocytes, chondrocytes and neural cells. If confirmed, these data would support the use of these cells, which are easily obtained from extracted teeth, in dental therapies, including in regenerative endodontics, providing a new therapeutic modality.