Stem cells: A potential regenerative future in dentistry

Application of neurotransmitters and dental stem cells for pulp regeneration: A review

Introduction

Although there have been many studies on stem cells, few have investigated how neurotransmitters and stem cell proliferation interact to regenerate dental pulp. Dental pulp regeneration is an innovative procedure for reviving dental pulp, if feasible for the entire tooth. Upon tooth injury, activated platelets release serotonin and dopamine in bulk to mobilize dental pulp stem cells to mediate natural dental repair. This has induced research on the role of neurotransmitters in increasing the proliferation rate of stem cells. This review also covers prospective future treatments for dental pulp regeneration.

Methods

A literature search was performed via PubMed and ScienceDirect from 2001 to 2022, using the keywords "neurotransmitter," "stem cell," "tooth regeneration," "tooth repair," "regenerative dentistry," and "dental pulp." Different inclusion/exclusion criteria were used, and the search was restricted to English articles.

Results

Nine publications reporting neurotransmitter interactions with stem cells for tooth and pulp regeneration were selected.

Conclusion

Neurotransmitters were found to interact with dental stem cells. Evidence pointing to neurotransmitters as a factor in the increased proliferation of stem cells was found. This review thus gives hope for tooth pulp regeneration and repair.

Knowledge and Attitude of Undergraduate Students and Interns toward Stem Cells and Their Implications in Dentistry: A Cross-sectional Study

AIM

The primary ideology of this research was to evaluate both the knowledge and attitude of undergraduate students and interns regarding stem cells and their use in dentistry.

MATERIALS AND METHODS

A cross-sectional observatory study was conducted among 310 dental students of Jazan University by making use of a self-explanatory questionnaire, containing a set of 25 questions and was sent as e-mail through Google e-forms.

RESULTS

There was a good response rate of around 81.2%, of which 80.16% were aware of the fact that stem cells are unspecialized types of cells that come with the potential to turn into any cell type. Almost 65.08% of the participants considered the possibility to continue root formation post-trauma as the fundamental use of stem cells, and a majority (71.43%) of the participants showed great interest in garnering more knowledge and training in the area of stem cells. About 50% of the participants showed strong opposition to the concept of embryonic stem cells as these are basically fetched from an aborted fetus or from an embryo. There was a major section of the participants (79.76%) who were even keen on organizing more programs to create public awareness regarding stem cells. Mean knowledge and attitude scores among the participants were reported to be 7.57 ± 3.10 and 36.04 ± 6.51 respectively.

CONCLUSION

Overall, the level of knowledge and attitude of dental students and interns at Jazan University towards stem cells and their implications in dentistry can be interpreted as adequate.

CLINICAL SIGNIFICANCE

Advanced training and awareness campaigns on stem cells and dentistry would improve their knowledge and attitude.

Assessment of willingness of Saudi public to participate in a dental biorepository for research purposes

BACKGROUND

Biobanks/biorepositories are created to collect biospecimens for therapeutic and research uses. The success of the banking concept depends predominantly on the public's understanding and desire to contribute, which triggers several social, cultural, and ethical implications. The aim of this study is (1) to assess the willingness among adults attending outpatient clinics at King Abdulaziz Medical City to donate dental tissue samples to a biorepository for research purposes, (2) to identify the significant predictors for positive attitudes and willingness to donate dental bio-specimens.

METHODOLOGY

This is a cross-sectional study that targeted 401 adult outpatients attending King Abdulaziz Medical City in Riyadh, Saudi Arabia. The questionnaire focused on three main parts: demographic and personal characteristics, and previous experience regarding biorepositories (part I), knowledge about dental biorepositories (part II), and willingness and attitudes towards donating dental biospecimens (part III). Data collected were analyzed using the statistical program SAS (version 9.4) with 0.05 level of significance to determine the willingness of donating tissue to biobanks for biomedical research purposes, measure knowledge and attitude about biobanking, find the association between the assessed variables, and identify significant predictors of positive attitude to donate dental biospecimens.

RESULTS

66% of the participants were willing to donate dental biospecimens, however only 33.9% showed good level of knowledge. Despite the notable lack of knowledge, 54% respondents had favorable attitude towards donating dental biospecimens, and only 17% were negative while the remaining 29% were neutral. Previous involvement in medical research, previous blood testing or donation, female gender, higher education level, employment in a medical facility, and higher monthly income variables were found to be significantly associated with higher willingness to donate dental biospecimens.

CONCLUSION

Although the majority of the participants exhibited lack of knowledge about dental biorepositories, they showed high willingness and good attitude towards donating dental biospecimens. This favorable attitude is, in turn, encouraging for the future establishment of dental biorepositories in Saudi Arabia. Six factors were significantly associated with the willingness to donate dental biospecimens, out of these, female gender, previous blood testing/donation, previous involvement in medical research were found to be strong predictors.

Tissue Engineering with Stem Cell from Human Exfoliated Deciduous Teeth (SHED) and Collagen Matrix, Regulated by Growth Factor in Regenerating the Dental Pulp

Maintaining dental pulp vitality and preventing tooth loss are two challenges in endodontic treatment. A tooth lacking a viable pulp loses its defense mechanism and regenerative ability, making it more vulnerable to severe damage and eventually necessitating extraction. The tissue engineering approach has drawn attention as an alternative therapy as it can regenerate dentin-pulp complex structures and functions. Stem cells or progenitor cells, extracellular matrix, and signaling molecules are triad components of this approach. Stem cells from human exfoliated deciduous teeth (SHED) are a promising, noninvasive source of stem cells for tissue regeneration. Not only can SHEDs regenerate dentin-pulp tissues (comprised of fibroblasts, odontoblasts, endothelial cells, and nerve cells), but SHEDs also possess immunomodulatory and immunosuppressive properties. The collagen matrix is a material of choice to provide structural and microenvironmental support for SHED-to-dentin pulp tissue differentiation. Growth factors regulate cell proliferation, migration, and differentiation into specific phenotypes via signal-transduction pathways. This review provides current concepts and applications of the tissue engineering approach, especially SHEDs, in endodontic treatment.

Response of stem cells from human exfoliated deciduous teeth (SHED) to three bioinductive materials - An in vitro experimental study

Introduction

Stem cells have unmatched capacity and potential for regeneration and when used alone or in combination with scaffolds to replace or repair damaged cells, can differentiate into any mature cell.

Aim

To evaluate the functional differentiation potential of EMD (Enamel Matrix Derivative), MTA (Mineral Trioxide Aggregate) and Biodentine on Stem Cells from Human Exfoliated Deciduous teeth (SHED).

Objective

To determine functional differentiation potential (osteogenic/odontogenic) of various biomaterials on SHED.

Material and method

SHED derived from 5^th linear passage after sub-culturing were treated with EMD, MTA and Biodentine individually and their effect on cell viability was compared and evaluated by MTT (3-4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide) assay for 7 days. Alizarin red S staining was used to assess mineralization potential of these materials by the staining calcium deposits for 14 days. The results were analyzed using One-way ANOVA, Post hoc Tukey’s test for multiple comparisons.

Results

It was observed that EMD imparted the highest cell viability at the end of 7 days (p < 0.001) followed by Biodentine and MTA. Likewise EMD showed highest potential to enhanced mineralization and expression of dentine sialoprotein (p < 0.001) followed by Biodentine and MTA at the end of 14 days (p<0.001).

Conclusion

It can be concluded that all the tested materials are bioinductive to SHED. EMD can be used for various vital pulp therapies as that of Biodentine and MTA with predictable as well as enhanced success rate.

Protective effect of epigenetic silencing of CyclinD1 against spinal cord injury using bone marrow-derived mesenchymal stem cells in rats

This study focuses on the protective effect of epigenetic silencing of CyclinD1 against spinal cord injury (SCI) using bone marrow-derived mesenchymal stem cells (BMSCs) in rats. Eighty-eight adult female Wistar rats were randomly assigned into the sham group, the control group, the si-CyclinD1 + BMSCs group and the BMSCs group. CyclinD1 protein and mRNA expressions after siRNA transfection were detected by Western blotting and qRT-PCR. The siRNA-CyclinD1 BMSCs were transplanted into rats in the si-CyclinD1 + BMSCs group using stereotaxic method 6 hr after SCI. Hindlimb locomotor performance was determined using inclined plane test and Basso-Beattie-Bresnahan (BBB) locomotor rating scale. Expressions of glial fibrillary acidic protein (GFAP) and nerve growth factor (NGF) were detected by immunohistochemistry. Inclined plane and BBB scores in the control, si-CyclinD1 + BMSCs, and BMSCs groups were significantly lower than the sham group, but these scores were evidently decreased in the control group and increased in the si-CyclinD1 + BMSCs group compared with the BMSCs group. The repair degree of spinal cord tissues of rats in the si-CyclinD1 + BMSCs group was obvious than the BMSCs group. GFAP and NGF protein expressions were markedly decreased in the control, si-CyclinD1 + BMSCs and BMSCs groups when compared with the sham group. GFAP- and NGF-positive cells were significantly increased in the si-CyclinD1 + BMSCs group while decreased in the control group. Our study provides evidence that epigenetic silencing of CyclinD1 using BMSCs might accelerate the repair of SCI in rats.

Comparative evaluation of the isolation and quantification of stem cells derived from dental pulp and periodontal ligament of a permanent tooth and to assess their viability and proliferation on a platelet-rich fibrin scaffold

BACKGROUND

The present study aims to comparatively evaluate the isolation and quantification of stem cells derived from dental pulp and periodontal ligament of a permanent tooth and to assess their viability and proliferation on a platelet-rich fibrin (PRF) scaffold.

MATERIALS AND METHODS

A total of 15 systemically healthy individuals between the age group of 15-25 years requiring third molar or orthodontic premolar extractions. Teeth were extracted atraumatically and transported to the laboratory. Stem cells were isolated from dental pulp and periodontal ligament. After attaining more than 90% confluency by the 7th day, these cells were tested for their viability and characterization. Stem cells were also incubated with PRF and viability was assessed on the 7th day.

RESULTS

The mean number of cell for dental pulp stem cells (DPSCs) and periodontal ligament stem cell (PDLSC) was statistically insignificant (P > 0.05). The mean live cell viability was compared between DPSC (98.07%) and PDLSC (98%). Both DPSC and PDLSC showed a high percentage of expression of CD73 markers, 30.40% and 29.80%, respectively. However, DPSCs and PDLSCs lacked expression of CD34 expressing only 3.47% and 3.53%, respectively. PRF membrane as a scaffold exhibited no cytotoxic effects on DPCS's or PDLSC's. The cell viability of cells cultured with PRF was statistically insignificant (P > 0.05) when compared to the cells cultured with culture media.

CONCLUSION

The study thus indicates that dental pulp and periodontal ligament are both rich sources of mesenchymal stem cells and can be successfully used for obtaining stem cells. PRF exhibits no cytotoxic effects on the cells and can be used in conjunction with dental stem cells.