Tooth replantation with adipose tissue stem cells and fibrin sealant: microscopic analysis of rat's teeth

Assessment of the effects of citric acid and EDTA on cell viability of cultured human periodontal ligament cells attached to simulated avulsed permanent tooth using a spectrofluorometer-An in vitro study

BACKGROUND/AIM

The delayed re-implantation of avulsed teeth results in ankylosis, followed by replacement resorption and eventual loss of the tooth within 2-4 years. To prevent tooth loss, the root surface can be etched with acid to expose the collagen fibers present in the cementum layer. This process facilitates normal reattachment and regeneration of the periodontal ligament. This in-vitro study aimed to assess the viability and number of attached cultured Human Periodontal Ligament Cells (HPLC) on the dehydrated root surface of simulated avulsed teeth treated with citric acid and EDTA solutions.

MATERIALS AND METHODS

Sound human permanent teeth were included in the study. The root portions of the teeth were sectioned into slices, air-dried for 1 h, and divided into the following three groups: Group A-control; Group B-Citric acid treated for 30 min; Group C-EDTA treated for 5 min. The slices were then placed in cultured HPLC. After a 24-h incubation period, the slices were visualized under the microscope and prepared for reading the viable and dead HPLC using a spectrofluorometer, as well as for counting HPLC in a Neubauer Chamber.

RESULTS

The spectrofluorometer intensity for viable and dead HPLC showed a statistically significant difference (p = .003 and p = .002), with the mean intensity for viable HPLC greater in citric acid group (69.52 ± 74.51), followed by EDTA group (31.39 ± 9.12), and control group (-130.93 ± 30.99). The dead HPLC intensity was greater in the EDTA group (19.43 ± 47.31), followed by the citric acid group (1.28 ± 1.85), and the control group (-2.77 ± 0.76). The total number of cells in the Neubauer chamber showed a statistically significant difference (p < 0.001), with a higher count in the citric acid group (10.83 ± 4.08) followed by EDTA group (2.92 ± 2.92).

CONCLUSION

The application of citric acid for 30 min on the dehydrated root surface of avulsed teeth demonstrated superior outcomes compared to both EDTA treatment for 5 min and the control group.

Mechanisms and clinical application potential of mesenchymal stem cells-derived extracellular vesicles in periodontal regeneration

Periodontitis is a high prevalence oral disease which damages both the hard and soft tissue of the periodontium, resulting in tooth mobility and even loss. Existing clinical treatment methods cannot fully achieve periodontal tissue regeneration; thus, due to the unique characteristics of mesenchymal stem cells (MSCs), they have become the focus of attention and may be the most promising new therapy for periodontitis. Accumulating evidence supports the view that the role of MSCs in regenerative medicine is mainly achieved by the paracrine pathway rather than direct proliferation and differentiation at the injured site. Various cells release lipid-enclosed particles known as extracellular vesicles (EVs), which are rich in bioactive substances. In periodontitis, EVs play a pivotal role in regulating the biological functions of both periodontal tissue cells and immune cells, as well as the local microenvironment, thereby promoting periodontal injury repair and tissue regeneration. As a cell-free therapy, MSCs-derived extracellular vesicles (MSC-EVs) have some preponderance on stability, immune rejection, ethical supervision, and other problems; therefore, they may have a broad clinical application prospect. Herein, we gave a brief introduction to MSC-EVs and focused on their mechanisms and clinical application in periodontal regeneration.

The influence of different dimensions of oral health literacy on parental attitudes and comprehension of an information leaflet about permanent tooth avulsion

BACKGROUND/AIM

Permanent tooth avulsion requires proper management at the time of the accident and parental oral health literacy (OHL) may influence decision-making with regards to dental trauma. The aim of this study was to investigate the influence of OHL on: (1) self-rated comprehension of an information leaflet (IL), (2) self-rated capacity to execute the tasks proposed on the IL, and (3) attitudes regarding the avulsion of a permanent tooth in children.

MATERIAL AND METHODS

A longitudinal study was conducted involving the reading of an IL by 466 parents/caregivers. Evaluations were performed prior to the IL (Phase I), immediately after the application of the IL (Phase II) and 60 days after the application of the IL (Phase III). Self-rated comprehension and capacity to execute the proposed tasks were analyzed in Phase II. Attitude was evaluated in all three phases. Functional OHL was measured using the BREALD-30 and interactive OHL was measured using HeLD-14.

RESULTS

Correlations were found between self-rated comprehension and both the OHL/BREALD-30 score (rs = 0.179; p = .012) and OHL/HeLD-14 score (r = 0.258; p < .001). Correlations were also found between the self-rated capacity to execute the proposed tasks and both the OHL/BREALD-30 score (rs = 0.133; p = .047) and the OHL/HeLD-14 score (rs = 0.225; p < .001). Higher BREALD-30 and HeLD-14 scores were associated with a better performance regarding parental attitudes toward permanent tooth avulsion comparing Phases I and II and Phases II and III (p < .05).

CONCLUSIONS

Higher levels of OHL were associated with better parental self-rated comprehension of the IL and the capacity to execute the tasks proposed therein as well as more adequate attitudes regarding the avulsion of a permanent tooth.

A new direction in managing avulsed teeth: stem cell-based de novo PDL regeneration

Management of avulsed teeth after replantation often leads to an unfavorable outcome. Damage to the thin and vulnerable periodontal ligament is the key reason for failure. Cell- or stem cell-based regenerative medicine has emerged in the past two decades as a promising clinical treatment modality to improve treatment outcomes. This concept has also been tested for the management of avulsed teeth in animal models. This review focuses on the discussion of limitation of current management protocols for avulsed teeth, cell-based therapy for periodontal ligament (PDL) regeneration in small and large animals, the challenges of de novo regeneration of PDL on denuded root in the edentulous region using a mini-swine model, and establishing a prospective new clinical protocol to manage avulsed teeth based on the current progress of cell-based PDL regeneration studies.

Application of Adipose Tissue Stem Cells in Regenerative Dentistry: A Systematic Review

AIM

The aim of this study was to systematically review the applications of adipose tissue stem cells (ADSCs) in regenerative dentistry.

MATERIALS AND METHODS

An electronic search was conducted in Medline (PubMed) and Scopus databases. The original research associated with the role of ADSCs in regeneration of alveolar bone, periodontal ligament (PDL), cementum as well as the dental pulp was evaluated. Among the included studies, three animal studies and one human study had low risk of bias.

RESULTS

A total of 33 relevant studies were included in the review. The animal models, in vivo human, and in vitro studies revealed that ADSCs had a significant osteogenic differentiation potential. Besides, they had potential to differentiate into PDL, cementum, and dental pulp tissue.

CONCLUSION

The ADSCs may be specifically applied for bone tissue engineering in the management of alveolar bone defects, specifically in dental implants and periodontal disease. However, their role in regeneration of PDL, cementum, and dental pulp requires further investigations. Overall, their applications in regenerative dentistry needs further verification through human clinical trials.

Cell-Based Therapy for Tooth Replantation Following Avulsion: A Systematic Review

The management of avulsed teeth undergoing delayed replantation remains a clinical challenge as there are currently no effective interventions that can improve periodontal healing and prevent replacement root resorption. While several preclinical studies have reported varied success using cell-based tissue engineering to improve periodontal healing, a consensus is required before further clinical translation. Therefore, this systematic review seeks to evaluate the efficacy of cell-based therapy in promoting periodontal healing following delayed replantation in animal models. MEDLINE (PubMed) and Embase were searched on September 27, 2020. Ten studies involving rodent and dog models met the inclusion criteria. Cell sources included gingiva, periodontal ligament (PDL), bone marrow, and adipose tissues. Generally, cell-based therapy had increased the proportion of root surfaces displaying periodontal healing and concomitantly reduced the proportion presenting with replacement root resorption and ankylosis. The best outcomes were observed following treatment with PDL-derived cells of various potency. Future preclinical studies will benefit from adopting measures to minimize bias during the conduct of animal experiments and the standardization of the outcome measures reporting. This will facilitate future reviews with possible pooling of results in the form of meta-analyses, allowing a consensus to be obtained from the literature. In addition, further research will be required to shed light on the implications of using allogeneic cells as well as the optimization of cell delivery protocols. The findings of this systematic review demonstrated the therapeutic potential of certain cell-based therapies in promoting periodontal healing following delayed replantation, thus highlighting their prospective clinical benefits and translational value.

Geomorphologic study of human tooth root surfaces following simulated avulsion by scanning electron microscopy

BACKGROUND/AIMS

Tooth avulsion is the most severe traumatic tooth injury. Immediate replantation after avulsion provides the highest success rate, whereas delayed replantation with dehydration for >1 h always results in ankylosis, replacement resorption, and eventual tooth loss. The aim of this study was to investigate the geomorphologic change of ultrastructure on tooth root surfaces due to dehydration.

MATERIAL AND METHODS

Twenty-four sound human premolars and fully developed third molars without periodontitis were selected for the experiment. Roots were separated into 6-7 pieces with an intact root surface area (3 × 3 mm² ) and then divided into the following groups: fresh group, prolonged dehydration groups (air drying for 1, 2, 4, 12, or 24 h), and dehydrated teeth (air drying for 2 h) treated with acid (Tris-HCl buffer or citric acid buffer). More than six pieces of root from each group were subjected to scanning electron microscopy (SEM) observation. Captured images were exported to ImageJ software to quantitatively analyze the areas covered with fibers. Statistical significance was determined by comparing the means of the different groups using t-testing or one-way analysis of variance followed by post hoc testing.

RESULTS

Fibrous "vegetation" covering the cementum was observed on the fresh root surface by SEM. This was destroyed by dehydration (>1 h), resulting in a root surface resembling the "Gobi Desert." The difference was statistically significant (p < .001). Root surface deteriorated by dehydration could be recovered by the re-use of the fibers embedded in the cementum as acid demineralization of the outer layer of cementum exposed the embedded fibers to simulate the geomorphology of fresh root surface.

CONCLUSIONS

Dehydrated teeth had deteriorated geomorphology of the root surface, which could be reversed by the re-use of the fibers embedded in the cementum using citric acid. Direct evidence from SEM gives new insights into the replantation of dehydrated avulsed teeth.

Transplantation of Adipose-derived Cells for Periodontal Regeneration: A Systematic Review

This systematic review evaluated the transplantation of cells derived from adipose tissue for applications in dentistry. SCOPUS, PUBMED and LILACS databases were searched for in vitro studies and pre-clinical animal model studies using the keywords "ADIPOSE", "CELLS", and "PERIODONTAL", with the Boolean operator "AND". A total of 160 titles and abstracts were identified, and 29 publications met the inclusion criteria, 14 in vitro and 15 in vivo studies. In vitro studies demonstrated that adipose- derived cells stimulate neovascularization, have osteogenic and odontogenic potential; besides adhesion, proliferation and differentiation on probable cell carriers. Preclinical studies described improvement of bone and periodontal healing with the association of adipose-derived cells and the carrier materials tested: Platelet Rich Plasma, Fibrin, Collagen and Synthetic polymer. There is evidence from the current in vitro and in vivo data indicating that adipose-derived cells may contribute to bone and periodontal regeneration. The small quantity of studies and the large variation on study designs, from animal models, cell sources and defect morphology, did not favor a meta-analysis. Additional studies need to be conducted to investigate the regeneration variability and the mechanisms of cell participation in the processes. An overview of animal models, cell sources, and scaffolds, as well as new perspectives are provided for future bone and periodontal regeneration study designs.