Effect of benzalkonium chloride addition to EDTA on attachment and proliferation of dental pulp stem cells on dentin and on transforming growth factor-β1 release

Comparative evaluation of pH and Ca + ion release from MTA on interaction with platelet-rich fibrin and blood clot: an in vitro study

Background: 'Regenerative endodontics' using host-derived scaffolds and biomaterials (MTA) is popular in the management of teeth with open apex. Alkaline pH and bioactivity contribute to tissue healing and remineralization. We assessed the influence of PRF and Blood Clot on the pH and Ca + ion release from MTA. Methods: A total of 15 single-rooted human extracted teeth were sectioned at the level of the cementoenamel junction. Based on the type of scaffolds used, samples were divided into three groups. Group 1 (MTA+ PRF), Group 2 (MTA + Blood Clot), Group 3 (control MTA). The prepared specimens were transferred to a fresh falcon tube containing 10mL of distilled water and the collected solutions were analysed for pH and Ca + ion release at 3h, seventh day and 14 th day. Results: It was observed that the mean pH and Ca + ion release were significantly lower in the experimental groups as compared to the control group. Though there was an increase in the pH recorded in Group 1 and 2 at all time periods, the difference was not significant. Ca + ion release peaked at Day 7 (Group3 > Group2 > Group1) and reduced significantly on the 14 th day for all groups. Conclusions: Within the limitations of the study, it can be concluded that PRF and blood clot influence the pH and Ca + ion release from MTA.

Transforming growth factor-β1 promotes early odontoblastic differentiation of dental pulp stem cells via activating AKT, Erk1/2 and p38 MAPK pathways

Background/purpose

TGF-β1 (Transforming growth factor-β1) plays an important role in the regeneration and repair of pulp-dentin complex. However, the biological function of TGF-β1 on odontoblastic differentiation remains unclear, mainly due to the processes of differentiation were controlled by complex signaling pathways. This study aimed to investigate the signaling pathways involved in regulating the early differentiation of dental pulp stem cells (DPSCs) by TGF-β1 and their functional role.

Materials and methods

DPSCs were treated with 1 ng/mL TGF-β1 and Western blotting was conducted to examine the activation of protein kinase B (AKT), small mothers against decapentaplegic 3 (Smad3), p38 mitogen-activated protein kinase (p38 MAPK), c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase 1/2 (Erk1/2). DPSCs were exposed to mineralization medium contained TGF-β1 with/without the specific signaling pathway inhibitors, and early odontogenic differentiation was evaluated by assessing the expression of alkaline phosphatase (ALP), collagen type 1 alpha 1 (COL1A), dentin matrix protein 1 (DMP-1) and runt-related transcription factor 2 (Runx2).

Results

TGF-β1 stimulated AKT, Smad3, p38 MAPK, Erk1/2 and JNK phosphorylation in DPSCs within 120 min. TGF-β1 enhanced ALP activity and elevated levels of COL1A, DMP-1 and Runx2. LY294002, U0126 and SB203580 attenuated the effect of TGF-β1 on DPSCs, however, the SIS3 and SP600125 treated groups had no significant effect.

Conclusion

TGF-β1 promotes the early stage of odontoblastic differentiation in DPSCs by activating AKT, Erk1/2 and p38 MAPK signaling pathways, but not by Smad3 and JNK.

Influence of ethylenediaminetetraacetic acid irrigation on the regenerative endodontic procedure in an immature rat molar model

AIM

To analyse the influence of ethylenediaminetetraacetic acid (EDTA) on the repair process in immature rat molars after a regenerative endodontic procedure (REP).

METHODOLOGY

The lower first molars of 12 4-week-old Wistar rats underwent pulpectomy in the mesial root and were divided into the following groups: sodium hypochlorite (NaOCl; n = 6) - the mesial canals were irrigated with 2.5% NaOCl for 5 min, and NaOCl-EDTA (n = 6) - the canals were irrigated with 2.5% NaOCl, followed by 17% EDTA for 5 min each. After evoking bleeding using a size 10 K-file, the cavities were sealed. Three molars on the untreated side were randomly used as control (control-15 d; n = 3), and three molars from the other three rats untreated were used as immediate control (n = 3). After 15 days (NaOCl, NaOCl-EDTA and control-15 d groups) or immediately (control-immediate), the animals were euthanized, and the teeth were subjected to histologic evaluation of tissue regeneration and presence of collagen fibres. Mann-Whitney U-test was used (p < .05).

RESULTS

The experimental groups had newly formed cementum-like tissue and increased root length and thickness. Half of the specimens in NaOCl-EDTA group showed apical foramen closure, whilst the NaOCl group had partial apical closure. The experimental groups showed inflammatory infiltrate extending mainly to the medium third of the root canal. These parameters were similar between experimental groups (p > .05). Newly formed connective tissue in the pulp space was significantly higher in the NaOCl-EDTA group than in NaOCl group (p < .05). Regarding the collagen fibres, the NaOCl-EDTA group had more collagen fibres in the root tip, but there was no significant difference compared to NaOCl group, and both groups showed greater amount of immature fibres in this area; in the centre of the apical third of root canal, there was equivalence between mature and immature fibres from both groups (p > .05).

CONCLUSIONS

Ethylenediaminetetraacetic acid irrigation improved newly formed intracanal connective tissue after REP in immature molars of rats; however, EDTA did not influence cementum-like tissue formation, apical closure, inflammatory infiltrate and maturation of collagen fibres.

Influence of ethylenediaminetetraacetic acid on regenerative endodontics: a systematic review

BACKGROUND

The effects of ethylenediaminetetraacetic acid (EDTA) on regenerative endodontic procedures (REPs) are controversial, because, despite releasing growth factors from dentine, some studies show negative effects on cell behaviour.

OBJECTIVES

To investigate the influence of the use of EDTA in REP on the growth factors' release, cell behaviour, and tissue regeneration.

METHODS

A systematic search was conducted (PubMed/Medline, Scopus, Cochrane Library, Web of Science, Embase, OpenGrey, and reference lists) up to February 2021. Only in vivo and in vitro studies evaluating the effects of EDTA on the biological factors of dentine, pulp/periapical tissues, and cell behaviour were eligible. Studies without a control group or available full text were excluded. The growth factors' release was the primary outcome. Risk of bias in the in vitro and in vivo studies was performed according to Joanna Briggs Institute's Checklist and SYRCLE's RoB tool, respectively.

RESULTS

Of the 1848 articles retrieved, 36 were selected. Among these, 32 were in vitro, three animal studies, and one with both models. The EDTA concentrations ranged from 3%-15%, at different times. Regarding growth factors' release (17 studies), 15 studies found significant transforming growth factor (TGF)-β release after dentine conditioning with EDTA, and most found no influence on vascular endothelial growth factor (VEGF) release. Regarding cell behaviour (26 studies), eight studies showed no influence of EDTA-treated dentine on cell viability; whereas, five, nine, and six studies showed higher cell migration, adhesion, and differentiation, respectively. No influence of EDTA conditioning was observed in animal studies. In vitro studies had a low risk of bias, whereas animal studies had high risk of bias. Meta-analysis was unfeasible.

DISCUSSION

This review found that EDTA increased TGF-β release and improved cell activity. However, well-designed histological analyses using immature teeth models are needed.

CONCLUSIONS

High quality in vitro evidence suggests that EDTA-treated dentine positively influences TGF-β release, cell migration, attachment, and differentiation; further research to evaluate its influence on tissue regeneration is necessary due to low methodological quality of the animal studies.

Effect of Different Root Canal Irrigant Solutions on the Release of Dentin-Growth Factors: A Systematic Review and Meta-Analysis

Irrigant solutions are used to promote dentin-growth factors (GF) release for regenerative endodontics. This review aimed to evaluate the reports comparing the release of GFs using different root canal irrigant solutions. Eligible studies compared the in vitro GF release in human teeth after the use of at least two distinct solutions. A search was conducted on Pubmed, Scopus, Web of Science, and Lilacs on 11 August 2021. Risk of bias was assessed using SciRAP. Study characteristics and quantitative data were extracted, and meta-analyses were performed for the mean difference (95% confidence interval) of the release of transforming growth factors Beta 1 (TGF-β1) by EDTA compared to other irrigants. Of sixteen eligible studies, eight were included in quantitative analysis. ELISA assays showed higher TGF-β1 release from 10% EDTA compared to 10% citric acid (p < 0.00001). Immunogold assays showed higher levels of TGF-β1 for 17% EDTA (p < 0.00001) compared to 10% citric acid. GRADE identified a low to very low certainty of evidence. These results point to an increased release of TGF-β1 in dentin treated with EDTA. The high heterogeneity and very low certainty of the evidence demand further studies before EDTA indication as a better irrigant for regenerative endodontics. Registration: CRD42020160871 (PROSPERO).