Tubular Dentin Research Articles

A Comparison of Two Fluorescent Stains for the Evaluation of Bioceramic Sealer Penetration into the Tubular Dentine Using Confocal Microscopy

This study aimed to compare the percentage of bioceramic sealer penetration and maximum penetration sealer depending on the fluorescent staining method when evaluated with confocal laser scanning microscopy (CLSM). In total, 42 single-rooted premolars were instrumented. Two groups of 20 teeth each were filled using the single cone technique. TotalFill BC Sealer® mixed with Rhodamine B was used for the first group and TotalFill BC Sealer® mixed with Fluo-3 for the second group. Two teeth made up the control group. All teeth were sectioned at 3 and 6 mm from the apex and were analyzed with CLSM. The canal perimeter where the tubular penetration happened and the maximum penetration of each sample were calculated. There were no significant differences between the two groups in either the apical or medial sections. In terms of maximum penetration, Rhodamine B had greater tubular penetration in the apical sections, and it had similar results to Fluo-3 in the medial sections. TotalFill BC Sealer® has a higher tubular penetration in the medial slices than in the apical slices regardless of the fluorescent stain used. Rhodamine B has higher results than Fluo-3 in terms of the percentage of sealer penetration and maximum penetration.

Biomimetic pulp scaffolds prepared from extracellular matrix derived from stem cells from human exfoliated deciduous teeth promote pulp-dentine complex regeneration.

To evaluate the role of biomimetic pulp scaffolds derived from the extracellular matrix derived of stem cells from human exfoliated deciduous teeth (SHED-ECM-PS) in promoting pulp-dentine complex regeneration. SHED-ECM-PS was prepared through cell aggregation and decellularization techniques. Histological and immunofluorescence analyses, scanning electron microscopy, and DNA quantification assays were used to characterize the SHED-ECM-PS. Additionally, a tooth slice implantation model was established to evaluate the effects of SHED-ECM-PS on regeneration of the pulp-dentine complex invivo. Extraction medium for SHED-ECM-PS was prepared, and its effect on bone marrow mesenchymal stem cells (BMMSCs) was assessed invitro. Cell counting kit-8 and Ki-67 staining assays were performed to determine cell proliferation. The rate of apoptosis was evaluated by flow cytometry. Wound healing and transwell assays were conducted to evaluate cell migration. Alizarin red S staining was performed to examine mineralized nodule formation. Western blotting was used to detect the expression of osteogenic and odontogenic markers. The results were analysed using an independent two-tailed Student's t-test. p < .05 was considered statistically significant. SHED-ECM-PS was successfully constructed, exhibiting a striped dental pulp-like shape devoid of nuclear structures or DNA components, and rich in fibronectin, collagen I, DMP1 and DSPP. Notably, SHED-ECM-PS showed no impact on the proliferation or apoptosis of BMMSCs. Histological analysis revealed that dental pulp fibroblasts formed an interwoven mesh in the root canal, and angiogenesis was observed in the SHED-ECM-PS group. Moreover, a continuous, newly formed tubular dentine layer with polarized odontoblast-like cells was observed along the inner wall of the root canal. SHED-ECM-PS promoted the migration, polar alignment and mineralized nodule formation of BMMSCs and specifically elevated the expression levels of odontogenic markers, but not osteogenic markers, compared with the control group invitro. SHED-ECM-PS exhibited no cytotoxicity and promoted pulp-dentine complex regeneration invivo as well as cell migration and odontogenic differentiation of BMMSCs invitro. These findings provide evidence that SHED-ECM-PS, as a novel biological scaffold, has the potential to improve the outcomes of REPs.

New proboscidean specimens from the Late Miocene of Romania: the huge-sized deinothere Deinotherium proavum, the rare “Mammut” cf. obliquelophus and the first description of the shovel-tusker Konobelodon from the country

In this article, we describe so far unpublished proboscidean specimens from several Late Miocene localities of Romania. A partial mandible and the complete upper/lower cheek tooth rows of a deinothere individual from the site of Gherghești 1 belong to Deinotherium proavum and comprise one of the few examples of entire cheek tooth rows of the same individual of this species. Gherghești 1 is geographically close to Mânzaţi from where the celebrated skeleton of “Deinotherium gigantissimum” was discovered at the end of the nineteenth century, and thus further highlights the importance of Romania in the study of this emblematic deinothere. Deinotherium proavum represents the last deinothere species in Europe and corresponds to the terminal stage of the size increase characterizing the evolution of European deinotheres. Two zygodont molars are attributed to the rare “Mammut” cf. obliquelophus and add to the scarce record of “Mammut” in the Miocene of Eurasia. They document the secure presence of “Mammut” in the Miocene of Romania. The small size of the studied molars compared to known specimens of the Pliocene “Mammut” borsoni and the weak development of the distal cingulum in the lower third molars may have taxonomic and biostratigraphic importance. Furthermore, the presence of an amebelodontid is documented by a large-sized and dorsoventrally flattened lower tusk fragment that shows tubular dentine in its inner part and is attributed to the tetralophodont shovel-tusker Konobelodon. This specimen marks the first record of the genus in Romania. Finally, the biostratigraphic distribution of the taxa is discussed.

Vapor Sublimation and Deposition Polymerization to Fabricate a Directional Scaffold for Guiding Tubular Dentin Regeneration

AbstractDental caries, or tooth decay, is a widespread problem and is generally considered irreversible, yet a regeneration solution exists to cure them. In this study, a multifunctional and biocompatible dental scaffold is fabricated by a unique vapor sublimation and deposition polymerization process with the well‐accepted material Parylene, resulting in the construction of a 3D and porous polymer scaffold that accommodates living cells and a combination of growth factor molecules in a single fabrication process, which differentiates the coating formation from a conventional vapor process. Physically, a directional interior structure is constructed to guide dental pulp stem cells (DPSCs) attachment and alignment. Biochemically, necessary growth factors, including Wnt‐3a and FGF‐2, are incorporated within the scaffold during fabrication to guide the cell differentiation of odontogenesis. The synergistic effects of the attachment and alignment of DPSCs, as well as the biocompatibility and odontogenic activities of the components accommodated in the scaffold, result in the upregulation of the cell differentiation into odontoblasts, as shown by the morphology of odontoblasts and the expressions of odontogenesis markers. Thus, the reported fabrication technique and its products represent an alternative approach for dentin regeneration in dental caries and tooth decay.

DILATED ODONTOMA ASSOCIATED WITH A DENTAL ROOT: A CASE REPORT

Dens invaginatus is an anomaly resulting from the enamel organ invagination into the dental papilla. When the invagination is extreme, it can dilate the crown and root, generating a so-called dilated odontoma, which is rare in the posterior mandible. A 47-year-old female presented an asymptomatic radiopaque mass attached to the distal root of the second lower molar, surrounded by a radiolucent halo. Computed tomography revealed a hypodense image within the mass. With the hypothesis of fusion, concrescence, and odontoma, the tooth and the lesion were removed. After demineralization, the material was hemisectioned, and a cavity within the calcified mass could be seen. Microscopic examination revealed that the mass consisted of tubular dentin, containing a cavity filled with empty clefts and irregular calcified tissue, consistent with the diagnosis of dilated odontoma. The radiological appearance of a dilated odontoma may vary, when the histological analysis is key to the final diagnosis. Dens invaginatus is an anomaly resulting from the enamel organ invagination into the dental papilla. When the invagination is extreme, it can dilate the crown and root, generating a so-called dilated odontoma, which is rare in the posterior mandible. A 47-year-old female presented an asymptomatic radiopaque mass attached to the distal root of the second lower molar, surrounded by a radiolucent halo. Computed tomography revealed a hypodense image within the mass. With the hypothesis of fusion, concrescence, and odontoma, the tooth and the lesion were removed. After demineralization, the material was hemisectioned, and a cavity within the calcified mass could be seen. Microscopic examination revealed that the mass consisted of tubular dentin, containing a cavity filled with empty clefts and irregular calcified tissue, consistent with the diagnosis of dilated odontoma. The radiological appearance of a dilated odontoma may vary, when the histological analysis is key to the final diagnosis.

Axin2-CreERT2 mediated knockout of bone morphogenetic protein receptor type 1A caused abnormal secondary dentine and altered cell fate of Axin2-expressing odontogenic cells.

Inducing odontogenic differentiation and tubular dentine formation is extremely important in dentine repair and tooth regeneration. Bone morphogenic proteins (BMPs) signalling plays a critical role in dentine development and tertiary dentine formation, whilst how BMPR1A-mediated signalling affects odontoblastic differentiation of Axin2-expressing (Axin2+ ) odontogenic cells and tubular dentine formation remains largely unknown. This study aims to reveal the cellular and molecular mechanisms involved in the formation of secondary dentine. Axin2lacZ/+ mice harvested at post-natal 21 (P21) were used to map Axin2+ mesenchymal cells. Axin2CreERT2/+ ; R26RtdTomato/+ mice and Axin2CreERT2/+ ; R26RDTA/+ ; R26RtdTomato/+ mice were generated to observe the tempo-spatial distribution pattern of Axin2-lineage cells and the effect of ablation of Axin2+ cells on dentinogenesis, respectively. A loss-of-function model was established with Axin2CreERT2/+ ; Bmpr1afl/fl ; R26RtdTomato/+ (cKO) mice to study the role of BMP signalling in regulating Axin2+ cells. Micro-computed tomography, histologic and immunostainings, and other approaches were used to examine biological functions, including dentine formation, mineralization and cell differentiation in cKO mice. The results showed rich expression of Axin2 in odontoblasts at P21. Lineage tracing assay confirmed the wide distribution of Axin2 lineage cells in odontoblast layer and dental pulp during secondary dentine formation (P23 to P56), suggesting that Axin2+ cells are important cell source of primary odontoblasts. Ablation of Axin2+ cells (DTA mice) significantly impaired secondary dentine formation characterized with notably reduced dentine thickness (Mean of control: 54.11 μm, Mean of DTA: 27.79 μm, p = .0101). Furthermore, malformed osteo-dentine replaced the tubular secondary dentine in the absence of Bmpr1a with irregular cell morphology, abnormal cellular process formation and lack of cell-cell tight conjunction. Remarkably increased expression of osteogenic markers like Runx2 and DMP1 was detected, whilst DSP expression was observed in a dispersed manner, indicating an impaired odontogenic cell fate and failure in producing tubular dentine in cKO mice. Axin2+ cells are a critical population of primary odontoblasts which contribute to tubular secondary dentine formation, and BMP signalling pathway plays a vital role in maintaining the odontogenic fate of Axin2+ cells.

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Oral DiseasesVolume 29, Issue 4 p. i-i FEATURED COVERFree Access Cover Image First published: 19 April 2023 https://doi.org/10.1111/odi.14592AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Graphical Abstract The cover image is based on the Original Article Tubular dentin formation by TGF-β/BMP signaling in dental epithelial cells by Yoon Seon Lee et al., https://doi.org/10.1111/odi.14170. Volume29, Issue4May 2023Pages i-i RelatedInformation

Evaluation of Mineral Trioxide Aggregate and Biodentine as Direct Pulp-capping Agents in Human Teeth: An Ex-Vivo Study

Introduction: Biodentine (Tricalcium Silicate based) is a modern bioactive cement that is comparable to the broadly utilized mineral trioxide aggregate (MTA). It has dentin-like mechanical properties, which can be considered appropriate material for diseased dentin-pulp complex recovery such as direct pulp capping. The present study was to compare the reaction of the pulp-dentin complex in human teeth after direct pulp capping with use of MTA and Biodentine. Objective: To assess the histomorphologic response of human dental pulps on direct pulp capping with MTA and Biodentine. Methods: Pulps of 34 maxillary permanent intact human third molars planned for extraction were mechanically exposed with sterile rotary round bur and allotted to one of the two exploratory groups, MTA or Biodentine. After four weeks, the teeth were extracted, stained with hematoxylin- eosin, and categorized by employing a preset histologic scoring framework. The histopathologic evaluations scored data were recorded and statically analyzed using SPSS where Mann-Whitney U test was used and p&lt;0.05 was considered statistically significant. Results: No inflammatory pulp reaction seen in 34 (100%) teeth whereas 19 (55.9 %) showed complete dentinal bridge arrangement. Layers of well-arranged odontoblast and odontoblast-like cells were found to make tubular dentin beneath the osteodentin. Inferential statistics using showed insignificance between the MTA and Biodentine test groups amid the perception period, showing similar outcomes. Conclusions: Biodentine had comparative adequacy in the clinical setting and may be considered an appropriate alternative to MTA as the pulp- capping agent.

Biomimetic Approaches in Clinical Endodontics.

In the last few decades, biomimetic concepts have been widely adopted in various biomedical fields, including clinical dentistry. Endodontics is an important sub-branch of dentistry which deals with the different conditions of pulp to prevent tooth loss. Traditionally, common procedures, namely pulp capping, root canal treatment, apexification, and apexigonesis, have been considered for the treatment of different pulp conditions using selected materials. However, clinically to regenerate dental pulp, tissue engineering has been advocated as a feasible approach. Currently, new trends are emerging in terms of regenerative endodontics which have led to the replacement of diseased and non-vital teeth into the functional and healthy dentine-pulp complex. Root- canal therapy is the standard management option when dental pulp is damaged irreversibly. This treatment modality involves soft-tissue removal and then filling that gap through the obturation technique with a synthetic material. The formation of tubular dentine and pulp-like tissue formation occurs when stem cells are transplanted into the root canal with an appropriate scaffold material. To sum up tissue engineering approach includes three components: (1) scaffold, (2) differentiation, growth, and factors, and (3) the recruitment of stem cells within the pulp or from the periapical region. The aim of this paper is to thoroughly review and discuss various pulp-regenerative approaches and materials used in regenerative endodontics which may highlight the current trends and future research prospects in this particular area.

Comparison of sealer penetration of sonic activation versus conventional needle irrigation: a systematic review and meta-analysis of randomized controlled trials

BackgroundMost existing studies comparing the efficiency of sonic irrigation (SI) and conventional needle irrigation (CNI) in increasing the penetration of sealers into dentine tubules are controversial; and this study aimed to determine whether the use of SI can lead to greater sealing ability than CNI, during the root canal treatment.MethodsThe EMBASE, PubMed, and Cochrane Library databases were used to find confocal laser scanning microscopy studies evaluating percentage and maximum depth of sealer penetration following the use of SI or CNI in mature permanent teeth until October 2022. The critical estimative checklist of randomized controlled trials of the standardized Joanna Briggs Institute was adopted to independently score the quality of each study. The random-effect model for meta-analysis was used to analyse for each canal segment (apical, middle, coronal). The results are shown in the forest plots as weighted mean differences (WMDs) with 95% confidence intervals (95% CIs).ResultsNinety-seven articles were included in the preliminary screening, and nine of them were included in this study. Eight studies were included in the meta-analysis.The meta-analysis exhibited great increases in the coronal (WMD: 8.09, 95% CI 2.78–13.40/WMD: 165.32, 95% CI 128.85–201.80), and middle segments (WMD: 8.81, 95% CI 5.76–11.87/WMD: 132.98, 95% CI 68.71–197.25) for the percentage and maximum depth of sealer penetration, respectively. The percentage of sealer penetration in the apical thirds region was nonsignificant (WMD: 4.73, 95% CI − 2.34–11.80). However, the maximum depth of sealer penetration in the apical thirds region was significant (WMD: 121.46, 95% CI 86.55–156.38). Chi-squared analysis revealed heterogeneity scores of 0.0–70.0% and 44.0–90.0% for the percentage and maximum depth of sealer penetration, respectively.DiscussionThis review verified that SI significantly improves tubular dentin sealer penetration in most areas of the root canal; thus, SI may lead to better filling efficiency and anti-reinfection effects than CNI during and after the root canal therapy. Nevertheless, a large heterogeneity in the current data comparing the irrigation efficiency of SI versus CNI in the apical third of the root canal was found, implying the necessity to standardize root canal irrigation procedures and obtain more accurate results in this area.Trial Registration: INPLASY database (INPLASY202270116).

Nanofibrous topography-driven altered responsiveness to Wnt5a mediates the three-dimensional polarization of odontoblasts.

Cell differentiation with the proper three-dimensional (3-D) structure is critical for cells to carry out their cellular functions in tissues. Odontoblasts derived from neural crest cells are elongated and polarized with the cell process, which is decisive for one directional tubular dentin formation. Here, we report that the fibrous topography of scaffolds directs odontoblast-lineage cells to differentiate to have the 3-D structure of odontoblasts through an altered responsiveness to Wnt family member 5A (Wnt5a). In a pulp-exposure animal model, the scaffolds with the nanofibrous topography supported the regeneration of tubular dentin with odontoblast processes. In cultures of pre-odontoblast cells, the nanofibrous topography heightened the cells on the z-axis. The cells on nanofibrous substrate (FIBER) formed stress fiber cytoskeletons on a conventional tissue culture plate (TCP). Differential activation of Cell division control protein 42 (Cdc42) on FIBER and Ras homolog family member A (RhoA) on TCP led to these differences. The signal from Wnt5a-Cdc42 in the cells on FIBER mediated the phosphorylation of JNK and the polarity growth signaling. Taken together, the nanofibrous topography of the scaffolds led to the 3-D structural differentiation of odontoblasts in vitro and in vivo, implying its application for dentin regeneration. Furthermore, the results on the altered activation of Cdc42 by Wnt5a on FIBER provide evidence that the topography of the scaffolds can cause a distinctive cell responsiveness to their micro-environments.

Novel strategy for dental caries by physiologic dentin regeneration with CPNE7 peptide

ObjectiveCPNE7-derived functional peptide (CPNE7-DP) has been introduced as a bioactive therapeutics for dentin diseases. CPNE7-DP regenerates tubular dentin on the pulpal side and occlude dentinal tubules. CPNE7-DP was capable to treat dentin hypersensitivity typically associated with dentinal wear at the neck of the tooth. However, the role of CPNE7-DP in another common dentin disease, dental caries, remains uninvestigated. In this study, we evaluated the potential application of CPNE7-DP in dentin caries using an experimental dentin caries model in rats. DesignThe stability of CPNE7-DP in caries-like environments including pathologic bacteria of caries or low pH was tested. We established a nutrition-time/hyposalivation-based dental caries rat model by inoculating caries-inducing bacteria and diet for sufficient time. Glycopyrrolate has been treated to induce reversible hyposalivation for accelerating caries progression. Then the tubular dentin regeneration was investigated with histologic methods. Also, modulation of inflammation or autophagy by CPNE7-DP was investigated with marker gene expression in human dental pulp cells (hDPCs) and immunohistochemistry. ResultsCPNE7-DP was stable with caries-inducing bacteria and low pH. Establishment of dentin caries was confirmed with radiographic and histologic evaluation. CPNE7-DP regenerated a substantial amount of tubular tertiary dentin and alleviated the pulp inflammation of dentin caries. Under inflammatory conditions, CPNE7-DP reduced the expression of inflammatory cytokines. These phenomena could be the consequence of the modulation of autophagy by CPNE7-DP, which reactivates inflamed odontoblasts. ConclusionsOverall, CPNE7-DP, which repairs caries through physiological dentin regeneration, might help overcoming the limitations of current restorative caries treatments.

Influencing factors of pulp-dentin complex regeneration and related biological strategies.

Regenerative endodontic therapy (RET) utilizing tissue engineering approach can promote the regeneration of pulp-dentin complex to restore pulp vascularization, neuralization, immune function and tubular dentin, therefore the regenerated pulp-dentin complex will have normal function. Multiple factors may significantly affect the efficacy of RET, including stem cells, biosignaling molecules and biomaterial scaffolds. Stem cells derived from dental tissues (such as dental pulp stem cells) exhibit certain advantages in RET. Combined application of multiple signaling molecules and activation of signal transduction pathways such as Wnt/β-catenin and BMP/Smad play pivotal roles in enhancing the potential of stem cell migration, proliferation, odontoblastic differentiation, and nerve and blood vessel regeneration. Biomaterials suitable for RET include naturally-derived materials and artificially synthetic materials. Artificially synthetic materials should imitate natural tissues for biomimetic modification in order to realize the temporal and spatial regulation of pulp-dentin complex regeneration. The realization of pulp-dentin complex regeneration depends on two strategies: stem cell transplantation and stem cell homing. Stem cell homing strategy does not require the isolation and culture of stem cells in vitro, so is better for clinical application. However, in order to achieve the true regeneration of pulp-dentin complex, problems related to improving the success rate of stem cell homing and promoting their proliferation and differentiation need to be solved. This article reviews the influencing factors of pulp-dentin complex regeneration and related biological strategies, and discusses the future research direction of RET, to provide reference for clinical translation and application of RET.

Insights Into Pulp Biomineralization in Human Teeth

IntroductionMineralized pulp (MP) compromises tooth function and its causation is unknown. The hypothesis of this study is that pulp mineralization is associated with pulpal tissue adaptation, increased mineral densities, and decreased permeabilities of tubular dentin and cementum. Methods will include correlative spatial mapping of physicochemical and biochemical characteristics of pulp, and contextualize these properties within the dentin-pulp complex (DPC) to reveal the inherent vunerabilities of pulp.MethodsSpecimens (N = 25) were scanned using micro X-ray computed tomography (micro-XCT) to visualize MP and measure mineral density (MD). Elemental spatial maps of MP were acquired using synchrotron X-ray fluorescence microprobe (μXRF) and energy dispersive X-ray spectroscopy (EDX). Extracted pulp tissues were sectioned for immunolabelling and the sections were imaged using a light microscope. Microscale morphologies and nanoscale ultrastructures of MP were imaged using scanning electron (SEM) and scanning transmission electron microscopy (STEM) techniques.ResultsHeterogeneous distribution of MD from 200 to 2,200 mg/cc, and an average MD of 892 (±407) mg/cc were observed. Highly mineralized pulp with increased number of occluded tubules, reduced pore diameter in cementum, and decreased connectivity in lateral channels were observed. H&amp;amp;E, trichrome, and von Kossa staining showed lower cell and collagen densities, and mineralized regions in pulp. The biomolecules osteopontin (OPN), osteocalcin (OCN), osterix (OSX), and bone sialoprotein (BSP) were immunolocalized around PGP 9.5 positive neurovascular bundles in MP. SEM and STEM revealed a wide range of nano/micro particulates in dentin tubules and spherulitic mineral aggregates in the collagen with intrafibrillar mineral surrounding neurovascular bundles. EDX and μXRF showed elevated counts of Ca, P, Mg, and Zn inside pulp and at the dentin-pulp interface (DPI) in the DPC.ConclusionColocalization of physical and chemical, and biomolecular compositions in MP suggest primary and secondary biomineralization pathways in pulp and dentin at a tissue level, and altered fluid dynamics at an organ level. Elevated counts of Zn at the mineralizing front in MP indicated its role in pulp biomineralization. These observations underpin the inherent mechano- and chemo-responsiveness of the neurovascular DPC and help elucidate the clinical subtleties related to pulpitis, dentin-bridge, and pulp stone formation.

Tubular dentin formation by TGF-β/BMP signaling in dental epithelial cells.

This study aimed to identify formation of tubular dentin induced by transforming growth factor-β (TGF-β) and bone morphogenic protein (BMP) signaling pathway in dental epithelial cells. We collected conditioned medium (CM) of rTGF-β1/rBMP-2-treated HAT-7 and treated to MDPC-23 cells. The expression levels of odontoblast differentiation markers, KLF4, DMP1, and DSP were evaluated by real-time PCR and Western blot analysis. To evaluate whether CM of rTGF-β1/rBMP-2 induces tubular dentin formation, we made a beagle dog tooth defect model. Here, we show that Cpne7 is regulated by Smad4-dependent TGF-β1/BMP2 signaling pathway in dental epithelial cells. CM of rTGF-β1/rBMP-2 treated HAT-7 or rCPNE7 raises the expression levels of KLF4, DMP1, and DSP in MDPC-23 cells. When rTGF-β1 or rBMP-2 is directly treated to MDPC-23 cells, however, expression levels of Cpne7-regulated genes remain unchanged. In a beagle dog defect model, application of rTGF-β1/BMP2-treated CM resulted in tubular tertiary dentin mixed with osteodentin at cavity-prepared sites, while rTGF-β1 group exhibited homogenous osteodentin. Taken together, Smad4-dependent TGF-β1/BMP2 signaling regulates Cpne7 in dental epithelial cells, and CPNE7 protein secreted from pre-ameloblasts mediates odontoblast differentiation via epithelial-mesenchymal interaction.

Histologic evaluation of dentin bridge formation by pachymic acid and biodentine in human tooth culture model

Histologic evaluation of dentin bridge formation by pachymic acid and biodentine in human tooth culture model

Pulp Revascularization and Regeneration: Differences, Utilization, and Outcome

Microbial, mechanical, physical, and chemical factors are strong enough to endanger tooth pulp, resulting in alterations and inflammation of its vasculature, and causing intolerable pain. Clinical and technical management of diseases of these tissues is oftentimes very difficult due to the vastly varied anatomical nature of the pulpal space. Root canal treatment has been used to scavenge the diseased pulp and allow healing of the supporting tissues. In a small proportion of teeth, the creation of the apical root structure Hertwig’s Epithelial Root Sheath may not be completed (causing an open apex) because of trauma or breach of the pulp by caries. In these scenarios, alternative techniques have been found, which regenerate a functional pulp tissue optimally. Regenerative endodontic procedures are biologically based techniques devised for predictable replacement of injured, infected, or missing structures with live viable tissues that restore the normal physiologic functions of the pulpdentine complex. Pulp revascularization is generally described as re-introduction of vascularity in the root canal system. Pulp regeneration, on the contrary, has not been accurately defined. Even though blood vessels are necessary components of dental pulp, pulpal regeneration is regarded incomplete without an odontoblastic layer bordering the dentin-pulp interface. Although the interactions with human pulp derived stem cells are still vague, it is suspected that conventional pulpal cells that resist infection can grow rapidly under the impact of Hertwig’s epithelial root sheath even during the inflammation stage; generating odontoblasts which has the ability to give rise to a tubular dentin, triggering apexogenesis. It is understood that similar and consistent outcomes in the endodontics are not always achieved. The pace of apex maturogenesis differs due to distinctive conditions of each case. A possibility of chronic necrosis my strip the pulpal tissue of remnants of viable cells and may lead to reduced capabilities to regenerate.

Dental Pulp Stem Cell Polarization: Effects of Biophysical Factors

Dental pulp stem cells (DPSCs) have the potential to polarize, differentiate, and form tubular dentin under certain conditions. However, the factors that initiate and regulate DPSC polarization and its underlying mechanism remain unclear. Identification of the factors that control DPSC polarization is a prerequisite for tubular dentin regeneration. We recently developed a unique bioinspired 3-dimensional platform that is capable of deciphering the factors that initiate and modulate cell polarization. The bioinspired platform has a simple background and confines a single cell on each microisland of the platform; therefore, it is an effective tool to study DPSC polarization at the single-cell level. In this work, we explored the effects of biophysical factors (surface topography, microisland area, geometry, tubular size, and gravity) on single DPSC polarization. Our results demonstrated that nanofibrous architecture, microisland area, tubular size, and gravity participated in regulating DPSC polarization by influencing the formation of the DPSC process and relocation of the Golgi apparatus. Among these factors, nanofibrous architecture, tubular size, and appropriate microisland area were indispensable for initiating DPSC polarization, whereas gravity served as an auxiliary factor to the process of DPSC polarization. Meanwhile, microisland geometry had a limited effect on DPSC polarization. Collectively, this work provides information on DPSC polarization and paves the way for the development of new biomaterials for tubular dentin regeneration.

Influence of chelating solutions on tubular dentin sealer penetration: A systematic review with network meta-analysis.

This systematic review assessed the influence of conventional final irrigation with chelating solutions (CS) on tubular dentin sealer penetration (TDSP). The literature search was conducted in eight electronic databases using MeSH, DeCS, EMTREE and free terms. The study protocol followed the PRISMA guidelines and was registered on the PROSPERO database (CRD42020203080). Twelve studies were included, and a qualitative synthesis and network meta-analysis of the data were performed. The risk of bias of the studies was assessed using an adaptation of the JBI Critical Appraisal tool. QMix was the solution with the highest probability of having the highest percentage of TDSP in the apical (34.1%), middle (86.5%) and coronal (97.7%) thirds. Eleven studies presented a moderate risk of bias, whereas one study presented a high risk of bias. In conclusion, CS improves sealer penetration into the dentinal tubules with QMix demonstrating superior results.

Sonic Activation Improves Bioceramic Sealer’s Penetration into the Tubular Dentin of Curved Root Canals: A Confocal Laser Scanning Microscopy Investigation

Background—The aim was to determine the influence of sonic activation in the tubular dentine penetration of bioceramic sealers. Methods—Forty mesiobuccal curved root canals of mandibular molars with an apical diameter smaller than #30 were prepared, divided into two groups, and filled with EndoSequence BC sealer, with or without sonic activation during its placement. Roots were sectioned at 3 mm, 6 mm, and 9 mm from the apex, producing a sample size of 120. The samples were evaluated using a confocal laser scanning microscope and comparing these images to the images obtained from an operatory microscope. The percentage of sealer penetration and maximum sealer penetration were evaluated. Statistical analysis was performed using the two-tailed Mann–Whitney U test, where statistical significance was set to p &lt; 0.05. Results—Sonic activation showed higher values for the percentage of sealer penetration when compared at the 9 mm level (p = 0.03). A higher value of maximum sealer penetration was observed at all levels when the sealer was activated. Conclusions—The sonic activation of bioceramic cement resulted in higher sealer penetration into dentinal tubules.