Dentin Conditioning Codetermines Cell Fate in Regenerative Endodontics

doi:10.1016/j.joen.2011.08.027

Journal of Endodontics

Volume 37, Issue 11, November 2011, Pages 1536-1541

https://doi.org/10.1016/j.joen.2011.08.027 Get rights and content

Abstract

Introduction

Recent successes in dental pulp engineering indicate that regenerative treatment strategies in endodontics are feasible. Clinically, revascularization procedures render completion of root formation in immature teeth. The generation of a pulp-like tissue after seeding of dental pulp stem cells into dentin discs or cylinders and transplantation in vivo is possible. In this experimental setup, which mimics the situation in the root canal, the pretreatment of dentin might influence cellular behavior at the cell-dentin interface. Thus, the objective of this study was to investigate whether dentin conditioning can determine cell fate.

Methods

Dental pulp stem cells (DPSCs) were seeded into a growth factor–laden peptide hydrogel, transferred into dentin cylinders, and transplanted subcutaneously into immunocompromised mice. Before cell seeding, dentin cylinders were either pretreated with sodium hypochloride (NaOCl) or conditioned with EDTA. The constructs were explanted after 6 weeks and subjected to histological and immunohistochemical analysis.

Results

In dentin treated with NaOCl, resorption lacunae were found at the cell-dentin interface created by multinucleated cells with clastic activity. After conditioning with EDTA, DPSCs adjacent to the dentin formed an intimate association with the surface, differentiated into odontoblasts-like cells that expressed dentin sialoprotein, and extended cellular processes into the dentinal tubules. A vascularized soft connective tissue similar to dental pulp was observed inside the dentin cylinder.

Conclusions

Dentin conditioning considerably influences DPSC fate when seeded in close proximity to dentin. This information might be critical for optimized strategic planning for future regenerative endodontic treatment.

Section snippets

Dentin Conditioning

Caries-free, extracted human incisors and molars were collected by local oral surgeons after written consent of the patients and stored in 0.5% chloramine (chloramine T hydrate; SIGMA-Aldrich, St. Louis, MO) at 4°C to avoid bacterial growth and contamination. For the scanning electron microscopic investigation, 5 incisors were subjected to root canal preparation (ProTaper; Dentsply Maillefer, Ballaigues, Switzerland) under constant irrigation with 5.25% NaOCl (Speiko, Münster, Germany). The

Scanning Electron Microscopic Analysis

Representative images from a total of 5 specimens per group are shown in Figure 1. The scanning electron microscopic images after dentin pretreatment with NaOCl or with EDTA exhibit distinct differences. Although the tissue-dissolving NaOCl did not remove the smear layer, which had been generated during root canal enlargement with a bur, this smear layer remained as a film covering the dentin surface (NaOCl, Fig. 1A). The fracture site shows dentinal tubules underneath the smear layer (NaOCl,

Discussion

Case reports on successful revascularization treatment in teeth with incomplete root formation 2, 3, 4, 5 have recently attracted the attention of clinicians as well as scientists in the field of endodontics, and they have sparked the discussion as to whether it was possible to restore the dentin-pulp complex. On another front, research studies with DPSCs have shown that dental pulp tissue engineering is possible. Stem cells from deciduous teeth seeded into dentin discs form a soft connective

Acknowledgments

The authors deny any conflicts of interest related to this study.

References (29)

F. Banchs et al.
Revascularization of immature permanent teeth with apical periodontitis: new treatment protocol?
J Endod
(2004)
I.Y. Jung et al.
Biologically based treatment of immature permanent teeth with pulpal necrosis: a case series
J Endod
(2008)
J.A. Petrino et al.
Challenges in regenerative endodontics: a case series
J Endod
(2010)
D. Pasqualini et al.
Comparative evaluation of the antimicrobial efficacy of a 5% sodium hypochlorite subsonic-activated solution
J Endod
(2010)
M. Rutberg et al.
Evaluation of enhanced vascular permeability of endodontic medicaments in vivo
J Endod
(1977)
D.J. Roberts-Clark et al.
Angiogenic growth factors in human dentine matrix
Arch Oral Biol
(2000)
S. Patel et al.
Internal root resorption: a review
J Endod
(2010)
E. Trevino et al.
Effect of irrigants on the survival of human stem cells of the apical papilla in a platelet-rich plasma scaffold in human root tips
J Endod
(2011)
K.C. Ring et al.
The comparison of the effect of endodontic irrigation on cell adherence to root canal dentin
J Endod
(2008)
M.M. Cordeiro et al.
Dental pulp tissue engineering with stem cells from exfoliated deciduous teeth
J Endod
(2008)

M. Rafter

Apexification: a review

Dent Traumatol

(2005)

S.Y. Shin et al.

One step pulp revascularization treatment of an immature permanent tooth with chronic apical abscess: a case report

Int Endod J

(2009)

M. Hülsmann et al.

Chelating agents in root canal treatment: mode of action and indications for their use

Int Endod J

(2003)

K. Verdelis et al.

Effect of chelating agents on the molecular composition and extent of decalcification at cervical, middle and apical root dentin locations

Endod Dent Traumatol

(1999)

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Effect of erbium yttrium aluminium garnet laser dentin conditioning on dental pulp stem cells viability
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This study aims to investigate the effect of dentin conditioning by subablative Er:YAG (erbium-doped yttrium aluminium garnet) laser on dental pulp stem cells (DPSCs) viability.
For this in-vitro experimental study, root fragments were longitudinally hemisected after decoronation of single-rooted extracted teeth and preparation of root canals. Prepared samples were randomly assigned to 2 experimental groups (n = 17) as follows; 1) laser conditioning: irradiation with Er:YAG laser beams (2940 nm, 50 mJ per pulse, 20 Hz) 2) Chemical conditioning: 1.5% NaOCl, followed by phosphate-buffered saline (PBS), 17% EDTA, followed by PBS as a final rinse. The samples were ultraviolet-sterilized, and DPSCs were seeded on the samples. MTT assay was performed after 1, 4 and 7 days of incubation to assess the cell viability (n = 5/group per day). Also, after 7 days, two samples of each group underwent SEM (scanning electron microscope) analysis. Statistical analysis was done using independent t-test, one-way ANOVA and two-way ANOVA at a significance level of 0.05.
Laser irradiated samples exhibited significantly higher cell viability of DPSCs on days 4 (p < 0.0001) and 7 (p < 0.0001), unlike day 1 (p = 0.131). SEM photomicrographs revealed that Er:YAG laser performed much better smear layer removal and created surface irregularities. Several different cell morphologies were observable on the laser-treated samples, which cells with cytoplasmic extensions being the most frequent.
Dentin conditioning by Er:YAG laser enhances DPSCs viability and can be a valuable modality for conditioning dentin to perform regenerative endodontic procedures. Further clinical studies are suggested.
De novo regeneration of dentin pulp complex mediated by Adipose derived stem cells in an immunodeficient albino rat model (Histological, histochemical and scanning electron microscopic Study)
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Dental tissue engineering is an alternative procedure for restoring damaged dental tissues. Adipose-derived stem cells are a new source of cells for regenerative endodontics in combination with scaffold materials. The descriptive data about this regenerative process is still insufficient.
To evaluate the regenerative potential of Adipose-derived stem cells using a self-assembling polypeptide scaffold for the dentin-pulp complex in an emptied root canal space.
40 root segments of human single-rooted teeth were transplanted into the albino rats’ dorsal subcutaneous tissue. Root segments were divided into two groups: group I contained only a self-assembling polypeptide scaffold, and group II contained fluorescent-labeled Adipose-derived stem cells embedded in a self-assembling polypeptide scaffold. The newly formed tissues were assessed on the 60^th and 90^th days post-transplantation using routine histological examination, Masson trichrome staining, and scanning electron microscopy.
Group I showed granulation tissue without any signs of predentin formation or odontoblast-like cells. Group II revealed the presence of predentin tissue along the dentin margin, with arranged odontoblast-like cells. An organized connective tissue with abundant vasculature and calcific masses was observed in the pulp space.
Adipose-derived stem cells can be considered as alternative stem cells for regenerating the dentin-pulp complex. Dentin pulp complex regeneration utilizing a self-assembling polypeptide scaffold alone would not yield successful results.
Effect of photobiomodulation therapy on TGF-β release from dentin, migration and viability of dental pulp stem cells in regenerative endodontics treatment: An ex vivo study
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Regenerative endodontic procedures (REPs) are oriented by the principles of tissue engineering, incorporating dental pulp stem cells (DPSC), crucial growth factors like Transforming growth factor-β (TGF-β1), and scaffolds to facilitate the regeneration of dental pulp tissues. The present study aimed to investigate the effect of photobiomodulation (PBM) therapy, using an 808 nm diode laser on cellular modulation mechanisms in REPs.
A total of 108 human dentin discs obtained from intact single root teeth were randomly assigned into six groups (n = 8): 1. Positive control (EDTA), 2. PBM-1 (3 J/cm²), 3. PBM-2 (5 J/cm²), 4. EDTA+PBM-1, 5. EDTA+PBM-2, and 6. Negative control (NaOCl). Then, an extract solution was prepared from each disc and the concentration of released TGF-β1 from the discs was measured using enzyme-linked immunosorbent assay (ELISA). Moreover, the extract solution was added to DPSC culture medium to evaluate cell viability and migration through MTT assay and scratch test, respectively.
The group exposed to PBM-1 showed the highest cell viability, while treatment with EDTA and EDTA+PBM-2 decreased cellular viability. Also, the PBM-treated groups showed significantly higher release of TGF-β1 compared to the negative control. EDTA and EDTA+PBM-1 showed the highest release among all the groups. No significant difference was found between EDTA and EDTA+PBM-1, as well as between PBM-1 and PBM-2. Moreover, the PBM-1 group exhibited the highest migration after 24 h, which was significantly greater than other groups, except for the PBM-2 group.
According to the obtained data, 808 nm mediated-PBM (3 J/cm2), both independently and in conjunction with EDTA, enhanced the release of TGF-β1 from dentin and improved cell viability and migration of DPSCs. It seems that, PBM under the specific parameters employed in this study, could be an effective adjunctive therapy in REPs.
Epigenetic therapeutics in dental pulp treatment: Hopes, challenges and concerns for the development of next-generation biomaterials
2023, Bioactive Materials
This opinion-led review paper highlights the need for novel translational research in vital-pulp-treatment (VPT), but also discusses the challenges in translating evidence to clinics. Traditional dentistry is expensive, invasive and relies on an outmoded mechanical understanding of dental disease, rather than employing a biological perspective that harnesses cell activity and the regenerative-capacity. Recent research has focussed on developing minimally-invasive biologically-based ‘fillings’ that preserve the dental pulp; research that is shifting the paradigm from expensive high-technology dentistry, with high failure rates, to smart restorations targeted at biological processes. Current VPTs promote repair by recruiting odontoblast-like cells in a material-dependent process. Therefore, exciting opportunities exist for development of next-generation biomaterials targeted at regenerative processes in the dentin-pulp complex. This article analyses recent research using pharmacological-inhibitors to therapeutically-target histone-deacetylase (HDAC) enzymes in dental-pulp-cells (DPCs) that stimulate pro-regenerative effects with limited loss of viability. Consequently, HDAC-inhibitors have the potential to enhance biomaterial-driven tissue responses at low concentration by influencing the cellular processes with minimal side-effects, providing an opportunity to develop a topically-placed, inexpensive bio-inductive pulp-capping material. Despite positive results, clinical translation of these innovations requires enterprise to counteract regulatory obstacles, dental-industry priorities and to develop strong academic/industry partnerships. The aim of this opinion-led review paper is to discuss the potential role of therapeutically-targeting epigenetic modifications as part of a topical VPT strategy in the treatment of the damaged dental pulp, while considering the next steps, material considerations, challenges and future for the clinical development of epigenetic therapeutics or other ‘smart’ restorations in VPT.
Fabrication and characterization of a novel injectable human amniotic membrane hydrogel for dentin-pulp complex regeneration
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Injectable biomaterials that can completely fill the root canals and provide an appropriate environment will have potential application for pulp regeneration in endodontics. This study aimed to fabricate and characterize a novel injectable human amniotic membrane (HAM) hydrogel scaffold crosslinked with genipin, enabling the proliferation of Dental Pulp Stem Cells (DPSCs) and optimizing pulp regeneration.
HAM extracellular matrix (ECM) hydrogels (15, 22.5, and 30 mg/ml) crosslinked with different genipin concentrations (0, 0.1, 0.5, 1, 5, and 10 mM) were evaluated for mechanical properties, tooth discoloration, cell viability, and proliferation of DPSCs. The hydrogels were subcutaneously injected in rats to assess their immunogenicity. The hydrogels were applied in a root canal model and subcutaneously implanted in rats to determine their regenerative potential for eight weeks, and histological and immunostaining analyses were performed.
Hydrogels crosslinked with low genipin concentration demonstrated low tooth discoloration, but 0.1 mM genipin crosslinked hydrogels were excluded due to their unfavourable mechanical properties. The degradation ratio was lower in hydrogels crosslinked with 0.5 mM genipin. The 30 mg/ml-0.5 mM crosslinked hydrogel exhibited a microporous structure, and the modulus of elasticity was 1200 PA. In vitro, cell culture showed maximum viability and proliferation in 30 mg/ml-0.5 mM crosslinked hydrogel. All groups elicited minimum immunological responses, and highly vascularized pulp-like tissue was formed in human tooth roots in both groups with/without DPSCs.
Genipin crosslinking improved the biodegradability of injectable HAM hydrogels and conferred higher biocompatibility. Hydrogels encapsulated with DPSCs can support stem cell viability and proliferation. In addition, highly vascularized pulp-like tissue formation by this biomaterial displayed potential for pulp regeneration.
Hydrogels for dental applications
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Tooth is one of the important organs which often gets affected by bacterial invasion, trauma, or congenital anomalies. According to the Centers for Disease Control and Prevention, more than 90% of adult faces different extent of tooth decay. Moreover, a large group of people older than 60 years old always face moderate to severe periodontal disease, which eventually results in tooth loss. In most common cases, dental caries can inflame the pulp tissues, requiring clinical treatment for the removal of necrotic dental tissues followed by filling them with biocompatible materials. Recently, with the increasing need for dental implants for the treatment of missing teeth, the number of cases of peri-implant diseases (PIDs) are also increasing. For the treatment of both periodontal and PIDs, various hydrogel-based biomaterials have been used extensively and become a well-known treatment strategy. On the other hand, while filling with bio-inert materials is reported to weaken the tooth and change its structure, artificial prosthetic dental implants are observed to cause peri-implant bone loss, infection, and allergic reactions. Therefore, simultaneous treatment of damaged teeth and regeneration of dental tissues with hydrogel-based scaffolds has become an alternative strategy, which is widely investigated in the area of dental tissue engineering.

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Basic ResearchDentin Conditioning Codetermines Cell Fate in Regenerative Endodontics

Abstract

Introduction

Methods

Results

Conclusions

Section snippets

Dentin Conditioning

Scanning Electron Microscopic Analysis

Discussion

Acknowledgments

J Endod

J Endod

J Endod

J Endod

J Endod

Arch Oral Biol

J Endod

J Endod

J Endod

J Endod

Apexification: a review

Dent Traumatol

One step pulp revascularization treatment of an immature permanent tooth with chronic apical abscess: a case report

Int Endod J

Chelating agents in root canal treatment: mode of action and indications for their use

Int Endod J

Effect of chelating agents on the molecular composition and extent of decalcification at cervical, middle and apical root dentin locations

Endod Dent Traumatol

Basic Research
Dentin Conditioning Codetermines Cell Fate in Regenerative Endodontics