Dentin-pulp Complex Research Articles

Regeneration of pulp-dentine complex-like tissue in a rat experimental model under an inflammatory microenvironment using high phosphorous-containing bioactive glasses.

To investigate the effects of a bioactive glass with a high proportion of phosphorus (BG-hP) on the repair and regeneration of dental pulps in rats under an inflammatory microenvironment. Human dental pulp cells (hDPCs) stimulated with 1μgmL-1 lipopolysaccharide (LPS) were co-cultured with 0.1mgmL-1 BG-hP. Cell proliferation was detected by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide (MTT) assays. The expression of inflammation-related genes and odontogenic differentiation-related genes was determined by real-time PCR. Alizarin red staining was used to detect the formation of mineralized nodules. Coronal pulp tissues of rat molars were stimulated with 10mgmL-1 LPS and then treated with BG-hP. The expression of inflammation-related genes in pulp tissue was determined by real-time PCR. Haematoxylin-eosin staining and Masson staining were performed to observe the inflammatory response and mineralized matrix formation, after subcutaneous implantation in nude mice, at 3days and 4weeks, respectively. Analysis of variance was performed to measure statistical significance (P<0.05). BG-hP significantly reduced expression of interleukin-6 (IL-6) and IL-8 and significantly upregulated the expression of IL-10, IL-4 and transforming growth factor-β1 of the LPS-stimulated hDPCs (P<0.05). BG-hP significantly inhibited the initial cell number (P<0.05), but the hDPCs stimulated by LPS and co-cultured with BG-hP maintained the same proliferation rate as the untreated hDPCs. BG-hP significantly promoted the expression of dentine matrix protein-1 and dentine sialophosphoprotein and the mineralization capacity of the LPS-stimulated hDPCs (P<0.05). Furthermore, BG-hP significantly downregulated the expression of Il-6 and reduced the inflammatory response of the LPS-stimulated pulp tissue 3days after subcutaneous implantation (P<0.05). Four weeks after subcutaneous implantation, BG-hP induced the formation of a continuous layer of dentine-like structure with dentinal tubules and polarizing odontoblast-like cells aligned along it in the LPS-stimulated pulp tissue. The present preliminarily results demonstrated that the bioactive glass with a high proportion of phosphorus inhibited the inflammatory response and promoted the formation of a pulp-dentine complex in a rat experimental model. This study provides a foundation for the construction of materials with the dual functions of exerting anti-inflammatory effects and promoting tissue regeneration to meet the needs of dental pulp repair and regeneration.

English

Traumatic injuries to an immature permanent tooth may result in cessation of dentin deposition and root maturation. Novel revascularisation endodontic procedure (REP) has been considered as an option for treatment of immature teeth with damaged pulp tissue. The continuous development of the root and the root canal has been recognised as a major advantage of this technique over traditional apexification approach. Traditional apexification procedures may resolve pathology but have not been able to prove tooth survival due to absence of continued root development and risk of root fracture. A successful REP results in resolution of signs and symptoms of pathology, radiographic signs of healing, proof of continued root development as well as presence of pulp vitality due to the regeneration of pulp tissue in the root canal. Currently, repair rather than true regeneration of the ‘pulp-dentine complex’ is achieved and further root maturation is variable. According to Glossary of Endodontic terms published by American Association of Endodontists, REP’s are biologically based procedures designed to physiologically replace damaged tooth structures, including dentin and root structures, as well as cells of the pulp-dentin complex.1,2 Apexification treatment has been a routine procedure to treat and preserve such teeth for many decades.3 Apexification is the process by which a suitable environment is created within the root canal and periapical tissue to allow for the formation of a calcific barrier across the open apex. Calcium hydroxide [Ca(OH)2] has been the material of choice for apexification as Frank reported its capacity to induce physiological closure of immature pulpless teeth in 1966.4 However, this technique has several disadvantages, including the unpredictability of apical barrier formation and the long duration of treatment, which often requires multiple visits.5 A retrospective study by Jeruphuaan et al.6 has shown a higher survival rate with regenerative endodontic treatment when compared to both mineral trioxide aggregate (MTA) and Ca(OH)2 apexification. The first evidence of regeneration of dental tissues was in 1932 by G.L. Feldman, who showed evidence of regeneration of dental pulp under certain optimal biological conditions.7 In 1971, a pioneer study in regenerative endodontics conducted by Nygaard-Ostby concluded that bleeding induced within a vital or necrotic canal led to resolution of signs and symptoms of necrotic cases and in certain cases, apical closure.8 According to Windley et al. (2005), the successful revascularisation of immature teeth with apical periodontitis is mainly dependent upon: 1. Canal disinfection 2. Scaffold placement in the canal for the growing tissues 3. Bacteria-tight sealing of the access opening.9 The purpose of this case report is to illustrate the outcome of a revascularisation endodontic procedure in a non-vital immature young permanent central incisor.

A graphene oxide-copper nanocomposite for the regeneration of the dentin-pulp complex: An odontogenic and neurovascularization-inducing material

• Well-dispersed water soluble graphene oxide-copper nanocomposites is synthesized. • The GO-Cu can promote odontogenesis of DPSCs. • Odontogenesis and neurovascularization was observed in regenerated dentin-pulp-like tissues. Dentin–pulp complex tissue engineering is a promising novel therapy in endodontics. Materials currently used in regenerative endodontics, e.g., calcium hydroxide and mineral trioxide aggregate, do not ensure full regeneration of the dentin–pulp complex, especially in terms of neurovascular induction. In this study, we fabricated a water-soluble graphene oxide–copper nanocomposite (GO-Cu) and investigated its odontogenic and neurovascularization-inducing abilities by means of dental pulp stem cells (DPSCs). Low-dose (≤10 µg/mL) GO-Cu had no effect on DPSC viability and promoted proliferation and adhesion. DPSCs treated with GO-Cu differentiated into odontoblasts and secreted larger amounts of vascular endothelial growth factor (VEGF) and glia-derived neurotrophic factor (GDNF) just as when they were cultured on a GO-Cu–coated calcium phosphate cement (CPC/GO-Cu) scaffold. Human umbilical vein endothelial cells treated with GO-Cu showed more tube formation, higher VEGF expression, and a stronger migratory ability. In addition, immunomodulatory genes, including indoleamine 2,3-dioxygenase (IDO), human leukocyte antigen G (HLA-G), and hepatocyte growth factor (HGF), were upregulated in DPSCs by the GO-Cu treatment. When CPC/GO-Cu was transplanted subcutaneously into nude mice, dentin–pulp complex–like structures formed expressing dentin sialophosphoprotein (DSPP), CD31, and GAP43, and the mineralized area and blood vessel numbers were greater in the CPC/GO-Cu group than CPC-alone group. These results show odontogenic and neurovascularization-inducing abilities of GO-Cu and suggest its promising application in regenerative endodontics.

Therapeutic potential of mesenchymal stem cell-derived extracellular vesicles in regenerative endodontics.

Regenerative endodontic procedures are an alternative to conventional root-canal treatment and apexification. There are two different tissue engineering approaches that are currently followed, both aiming at the colonisation of the cleaned pulp space by pluripotent cells and subsequent pulp regeneration. Firstly, the transplantation of mesenchymal stem cells (MSCs), and secondly a cell-free strategy that relies on bioactive molecules to trigger the recruitment of the patient's own cells. The first approach is hampered by costs and regulatory issues. Despite great initial enthusiasm with a clinically used cell-free approach that relies on induced bleeding into the pulp space, results have been revealed to be rather unpredictable, and mere repair rather than regeneration of the pulp-dentin complex is what is typically achieved. Moreover, the extent of further root development is variable, and the concept is limited to immature teeth. This article discusses a third possible way of regenerative endodontics that involves the application of MSC-derived exosomes. These are extracellular vesicles that contain proteins, lipids, and nucleic acids, reflecting the secretome of MSCs. Based on the first in vitro and in vivo studies, exosomes appear to be a potent tool to improve pulp regeneration. This narrative review aims to investigate the therapeutic use of human MSCs or dental pulp-derived exosomes in regenerative endodontics. Furthermore, the focus of this review is on targeting important questions that should be investigated in future in-vivo and clinical studies, such as the choice of scaffold material for exosome delivery into the pulp space.

Detection of Inflammatory and Homeostasis Biomarkers after Selective Removal of Carious Dentin-An In Vivo Feasibility Study.

Deep carious dentin lesions induce an immune reaction within the pulp-dentin complex, leading to the release of cytokines, which might be suitable biomarkers in pulp diagnostics. This in vivo feasibility study determines the concentration of different cytokines after selective removal of carious infected dentin (SCR). In our methodology, paired samples are obtained from 21 patients—each of them with two deep carious lesions at posterior teeth without clinical symptoms. After SCR, lesions are randomly assigned to treatment strategy: Group 1 (11 patients): Carious dentin is covered either with BiodentineTM (n = 11) or gutta-percha (n = 11) before using the adhesive OptibondTM FL. Group 2 (10 patients): The adhesives ClearfilTM SE Protect Bond (n = 10) or ClearfilTM SE Bond 2 (n = 10) are directly applied. Prepared cavities are rinsed with phosphate buffered saline containing 0.05% Tween 20 (10X) for five minutes immediately after SCR (visit 1) and eight weeks later (visit 2). Rinsing liquid is regained. Concentrations of IL-1β, IL-6, IL-10, C-reactive protein (CRP), TNF-α, IFN-γ, TIMP-1, -2, and MMP-7, -8, -9 are assessed by customized multiplex assays, evaluated with fluorescence analyzer. Non-parametric statistical analysis (Wilcoxon, Mann–Whitney U Test, p < 0.05) is performed (SPSS 25). Our results show that concentrations of CRP, IL-1β, IL-6, TIMP-1, -2, and MMPs were detectable. Median concentrations of CRP, IL-1β und IL-6 were significantly higher in visit 1 (304.9, 107.4, 3.8 pg/mL), compared to visit 2 (67.8, 2.3, 0.0 pg/mL; pi < 0.001). The study revealed that the non-invasive determination of cytokines from prepared dental cavities is possible.

Vascular Endothelial Growth Factor and/or Nerve Growth Factor Treatment Induces Expression of Dentinogenic, Neuronal, and Healing Markers in Stem Cells of the Apical Papilla

IntroductionThe goal of regenerative endodontic procedures is to preserve and stimulate stem cells from the apical papilla (SCAPs) to develop the pulp-dentin complex using various growth factors and scaffolds. We hypothesized that the treatment of SCAPs with vascular endothelial growth factor (VEGF) or nerve growth factor (NGF) may impact the expression of osteogenic and dentinogenic markers. MethodsThe optimum concentration of VEGF and NGF on SCAP viability was assessed and introduced to SCAPs for 6–24 hours. SCAPs were also challenged with Escherichia coli lipopolysaccharide (LPS). Messenger RNA (mRNA) expression of DSPP, DMP1, TGFB1, OCN, SP7, and TWIST1 was examined via quantitative reverse transcription polymerase chain reaction. Immunohistochemistry was used to verify protein expression. In addition, total RNA from NGF-treated SCAPs in the presence or absence of LPS was extracted for RNA sequencing. ResultsCompared with untreated cells, NGF-treated SCAPs showed markedly higher levels of DSPP, DMP1, and TGFB1 mRNAs (>9-fold change, P < .05), and SCAPs treated with both VEGF and NGF showed a significant increase of DSPP and TGFB1 mRNAs (P < .05). In addition, in LPS-challenged SCAPs, treatment with these growth factors also exhibited increased expression of DSPP, DMP1, and TGFB1 mRNAs, with the most significant change induced by VEGF (P < .05). Immunohistochemistry confirmed increased dentin sialophosphoprotein, dentin matrix acidic phosphoprotein 1, and transforming growth factor beta 1 protein expression in treated SCAPs. RNA sequencing revealed multiple pathways regulated by NGF, including TGF-β and neurogenic pathways. ConclusionsVEGF- and NGF-induced dentinogenic/neuronal/healing marker expression in SCAPs indicates the potential value of applying these growth factors in regenerative endodontic procedures.

REJENERATİF ENDODONTİK TEDAVİDE BİYOMALZEME SEÇİMİ VE DOKU MÜHENDİSLİĞİ UYGULAMALARI

Dental pulp is a soft connective tissue that is surrounded by highly mineralized tissues such as enamel, dentin, cementum and provides homeostasis of the tooth. Pulp tissue is a specialized mineralized tissue with a limited regeneration ability due to the anatomical arrangement and postmitotic structure of odontoblastic cells. Classical endodontic treatment is based on removing the infected pulp tissue and root dentin and filling the disinfected canal cavity with a bioinert material to ensure hermetically sealed. It may quickly become necrotic due to tooth decay or inflammation and may require endodontic treatment. In immature that have not completed root formation and necrotic pulp teeth, an apical barrier is formed by using Ca(OH)2 and MTA (Mineral Trioxide Aggregate). There is no increase in root length and thickness in the tooth treated with these methods. For this reason, these teeth remain devital and weak teeth for life. The most desired in endodontic treatment is the replacement of devital and necrotic pulp with healthy pulp tissue. Regenerative endodontic therapy is an alternative to classical endodontic therapy. Regenerative endodontic therapy is defined as '' bio-based procedures designed to treat damaged tooth structures, including cells of the pulp-dentin complex, as well as dentin and root structures. ''Recent advances in biomaterial science and tissue engineering technology have encouraged the development of regenerative endodontic treatment method. Numerous studies are carried out in the field of regenerative endodontic treatment with stem cells, tissue scaffold and growth factors, which are the basis of tissue engineering. Pulp regeneration techniques that are currently proposed are still under development. In this review, studies on different stem cells, growth factors and tissue scaffolds used as the classical tissue engineering trio used in current regenerative endodontics are reviewed and the stages of the treatment procedure developed for routine clinical applications are summarized. In addition, organoids and organ-o-a-chip treatment approaches developed for regenerative endodontic applications were also presented. The relationship between regeneration and cancer was given. Finally, the stages of the treatment procedure developed for routine clinical applications were included.

Regeneration of pulp-dentin complex using human stem cells of the apical papilla: in vivo interaction with two bioactive materials.

To compare the regenerative properties of human stem cells of the apical papilla (SCAPs) embedded in a platelet-rich plasma (PRP) scaffold, when implanted in vivo using an organotypic model composed of human root segments, with or without the presence of the bioactive cements - ProRoot MTA or Biodentine. SCAPs were isolated from third molars with incomplete rhizogenesis and expanded and characterized in vitro using stem cell and surface markers. The pluripotency of these cells was also assessed using adipogenic, chondrogenic, and osteogenic differentiation protocols. SCAPs together with a scaffold of PRP were added to the root segment lumen and the organotypic model implanted on the dorsal region of immunodeficient rats for a period of 4 months. Presence of SCAPs induced de novo formation of dentin-like and pulp-like tissue. A barrier of either ProRoot MTA or Biodentine did not significantly affect the fraction of sections from roots segments observed to contain deposition of hard material (P > 0.05). However, the area of newly deposited dentin was significantly greater in segments containing a barrier of Biodentine compared with ProRoot MTA (P < 0.001). SCAPs offer a viable alternative to other dental stem cells (DSCs) in their regenerative properties when enclosed in the microenvironment of human tooth roots. The present study also suggests that the presence of bioactive materials does not hinder or impede the formation of new hard tissues, but the presence of Biodentine may promote greater mineralized tissue deposition.

Different Approaches to the Regeneration of Dental Tissues in Regenerative Endodontics

(1) Background: The regenerative procedure has established a new approach to root canal therapy, to preserve the vital pulp of the tooth. This present review aimed to describe and sum up the different approaches to regenerative endodontic treatment conducted in the last 10 years; (2) Methods: A literature search was performed in the PubMed and Cochrane Library electronic databases, supplemented by a manual search. The search strategy included the following terms: “regenerative endodontic protocol”, “regenerative endodontic treatment”, and “regenerative endodontics” combined with “pulp revascularization”. Only studies on humans, published in the last 10 years and written in English were included; (3) Results: Three hundred and eighty-six potentially significant articles were identified. After exclusion of duplicates, and meticulous analysis, 36 case reports were selected; (4) Conclusions: The pulp revascularization procedure may bring a favorable outcome, however, the prognosis of regenerative endodontics (RET) is unpredictable. Permanent immature teeth showed greater potential for positive outcomes after the regenerative procedure. Further controlled clinical studies are required to fully understand the process of the dentin–pulp complex regeneration, and the predictability of the procedure.

Inflammatory Response Mechanisms of the Dentine-Pulp Complex and the Periapical Tissues.

The macroscopic and microscopic anatomy of the oral cavity is complex and unique in the human body. Soft-tissue structures are in close interaction with mineralized bone, but also dentine, cementum and enamel of our teeth. These are exposed to intense mechanical and chemical stress as well as to dense microbiologic colonization. Teeth are susceptible to damage, most commonly to caries, where microorganisms from the oral cavity degrade the mineralized tissues of enamel and dentine and invade the soft connective tissue at the core, the dental pulp. However, the pulp is well-equipped to sense and fend off bacteria and their products and mounts various and intricate defense mechanisms. The front rank is formed by a layer of odontoblasts, which line the pulp chamber towards the dentine. These highly specialized cells not only form mineralized tissue but exert important functions as barrier cells. They recognize pathogens early in the process, secrete antibacterial compounds and neutralize bacterial toxins, initiate the immune response and alert other key players of the host defense. As bacteria get closer to the pulp, additional cell types of the pulp, including fibroblasts, stem and immune cells, but also vascular and neuronal networks, contribute with a variety of distinct defense mechanisms, and inflammatory response mechanisms are critical for tissue homeostasis. Still, without therapeutic intervention, a deep carious lesion may lead to tissue necrosis, which allows bacteria to populate the root canal system and invade the periradicular bone via the apical foramen at the root tip. The periodontal tissues and alveolar bone react to the insult with an inflammatory response, most commonly by the formation of an apical granuloma. Healing can occur after pathogen removal, which is achieved by disinfection and obturation of the pulp space by root canal treatment. This review highlights the various mechanisms of pathogen recognition and defense of dental pulp cells and periradicular tissues, explains the different cell types involved in the immune response and discusses the mechanisms of healing and repair, pointing out the close links between inflammation and regeneration as well as between inflammation and potential malignant transformation.

Long noncoding RNA MEG3 expressed in human dental pulp regulates LPS-Induced inflammation and odontogenic differentiation in pulpitis

Pulpitis refers to inflammation of the inner pulp by invading microbes, and tissue repair occurs due to odontogenic differentiation of human dental pulp cells (hDPCs) with multidifferentiation potential. Long noncoding RNAs (lncRNAs) can modulate numerous pathological and biological processes; however, the role of lncRNAs in the inflammation and regeneration of the dentin-pulp complex in pulpitis is unclear. Here, we performed high-throughput sequencing to identify differentially expressed lncRNAs between human normal and inflamed pulp and concluded that lncMEG3 (lncRNA maternally expressed gene 3, MEG3) was significantly upregulated in both inflamed pulp and LPS-treated hDPCs. MEG3 expression in the pulp tissue was detected using the RNAscope® technique. RNA pulldown assays identified the MEG3-interacting proteins and the potential mechanisms. With MEG3 knockdown, we investigated the role of MEG3 in the secretion of inflammatory cytokines in LPS-treated hDPCs and odontogenic differentiation of hDPCs. MEG3 downregulation inhibited the secretion of TNF-α, IL-1β and IL-6 in LPS-treated hDPCs, and the p38/MAPK signaling pathway may be related to this effect. MEG3 knockdown promoted odontogenic differentiation of hDPCs by regulating the Wnt/β-catenin signaling pathway. Our study suggested that MEG3 has a negative effect on inflammation and regeneration of the dentin-pulp complex in pulpitis.

Clinical cell‐based versus cell‐free regenerative endodontics: clarification of concept and term

There is no consensus on the true meaning of clinical regenerative endodontics, and there is confusion over the concept and the term. Commonly used terms include revitalization and revascularization. The clinical methods for endodontic revitalization procedures and the tissue engineering concept differ depending on whether there is exogenous delivery of cells - called cell therapy, or not. Here, in this review, the difference is clarified by emphasizing the correct terminology: cell-free versus cell-based regenerative endodontic therapy (CF-RET versus CB-RET). The revitalization procedures practised clinically do not fit into the modern tissue engineering concepts of pulp regeneration but can be categorized as CF-RET. The modern tissue engineering concept in pulp regeneration is a CB-RET, which so far is at the clinical trial stage. However, histological examination of teeth following regenerative endodontic treatments reveals healing with repair derived from stem cells that originate from the periodontal, bone and other tissues. The aim of regenerative endodontics is regeneration of the pulp-dentine complex. This review discusses why CF-RET is unlikely to regenerate a pulp-dentine complex with current protocols. The American Association of Endodontists and the European Society of Endodontology have not yet recommended autologous stem cell transplantation (CB-RERT) which aspires for regeneration. Therefore, an understanding of the concept, term, difficulties and differences in current protocols is important for the clinician. However, rather than being discouraged that ideal regeneration has not been achieved to date, repair can be an acceptable outcome in clinical regenerative endodontics as it has also been accepted in medicine. Repair should also be considered in the context that resolution of the clinical signs/symptoms of pulp necrosis/apical periodontitis is generally reliably obtained in clinical regenerative endodontics.

Involvement of substance P, osteopontin and satellite glial cells on photobiomodulation-induced antinociceptive effect in an experimental model of dentin hypersensitivity.

The aim of this work was to investigate the involvement of substance P (SP), osteopontin (OPN), and satellite glial cells (SGC) on photobiomodulation-induced (PBM) antinociceptive effect in an experimental model of dentin hypersensitivity (DH). Rats ingested isotonic drink (ID, pH 2.87) for 45 consecutive days and after this period received PBM irradiation at λ660 nm or λ808 nm (1 J, 3.5 J/cm2, 100 mW, 10 s, 0.028 cm2, continuous wave, 3 consecutive daily sessions), and were evaluated for nociceptive behavior 24, 48, 72 h, and 14 days after laser treatments. ID ingestion induced an increase on thermal sensitivity of DH characteristics in rats that was completely reversed by PBM treatment at both 660 and 808 nm. Immunohistochemical analysis revealed increased SP expression at both dentin-pulp complex (DPC) and trigeminal ganglia (TG) of DH-rats which did not occur in PBM groups by PBM treatment. Also, the increase of glial fibrillary acidic protein (GFAP) observed in the TG of DH-rats was also reversed by PBM treatment. Finally, PBM at both 660 and 808 nm increased OPN expression in the dentin-pulp complex of DH-rats after 14 days of PBM treatment. All in all, this data demonstrates that PBM reverses nociception in a DH experimental model by inhibiting neurogenic inflammation and inducing a regenerative response.

Tailored 70S30C Bioactive glass induces severe inflammation as pulpotomy agent in primary teeth: an interim analysis of a randomised controlled trial.

This study compared clinical, histologic, and inflammatory outcomes of Biodentine and Bioactive glass (70S30C-BAG) as pulpotomy agents in primary teeth. A randomised, clinical trial was performed recruiting 70 children, 5-9years old, having ≥ 1 tooth indicated for vital pulpotomy. Participants were randomised to Biodentine or 70S30C-BAG groups. Clinical evaluation was scheduled at 1, 3, 6, 9, and 12months. Additional 16 teeth were extracted after 6weeks to assess histologic and inflammatory response (IL-8/IL-10 ratio) using ELISA. Fisher exact, Mann Whitney U test, and t test were used to compare clinical, histologic outcomes and IL-8/IL-10 ratio. After 3months, 10 teeth treated with Biodentine were clinically successful, while 9 teeth treated with 70S30C-BAG failed (P < 0.001) necessitating trial termination. Causes of failure were analysed by assessing the pH and ionic release of 70S30C-BAG. Biodentine-treated teeth showed minor inflammation, normal pulp, and hard tissue formation.70S30C-BAG-treated teeth showed severe inflammation, abscesses, root resorption without hard tissue formation. There was a significantly greater percent reduction of IL-8/IL-10 ratio in Biodentine than 70S30C-BAG (mean ± SD = 66.39 ± 18.56 and 40.66 ± 0.86, P = 0.02). Biodentine showed favourable clinical, histologic, and anti-inflammatory outcomes, promoting pulp healing and regeneration. 70S30C-BAG resulted in pulp necrosis-through persistent inflammation-causing clinical failure. Biodentine is a promising pulpotomy agent in primary teeth; it promoted healing and regeneration of the dentine-pulp complex. In its current form, 70S30C-BAG is not a suitable pulpotomy agent; it induced persistent inflammation, negating the pulp ability to heal and regenerate. TRN: NCT03786302, 12/19/2018.

Regeneration of dentin-pulp complex by using dental pulp stem cells in dog

Although missing tooth is not life-threatening, it affects the quality of daily life. Stem cells have emerged as an important player in the generation and maintenance of many tissues. The role of scaffolds has changed from a passive carrier to a bioactive matrix, which can be used to induce cellular behavior. The aim of this study was to determine the possibility of regeneration of dentin-pulp complex with dental pulp stem cells (DPSCs) in an animal model. In this animal study after extraction of DPSCs and cultivation, 10 types of scaffolds were made by using platelet-rich plasma (PRP), cancellous bone, and collagen pad. They were inserted in different parts of the dog's mouth. After the 4th month, the area was operated, and the scaffolds were removed. Microscopic examination revealed no sign of cell differentiation and formation of new structures in those models which used collagen scaffolds. However, the dentin-pulp complex emerged in models that the combination of bone scaffolds and PRP or stem cells was used. Using bone scaffolds in combination with PRP or DPSCs to regenerate dentin-pulp complex in dog helped odontoblastic and pulpal differentiation as well as the formation of predentin and tubular dentin.

Morphological analysis and immunohistochemical expression in restorations with self-adhesive resin: A randomized split-mouth design-controlled study.

BackgroundTo evaluate the morphology and immunohistochemical expression of MMP-9, TIMP-3, COL-I, TNF-alfa and COX-2 in the dentinopulp complex of restorations with self adhesive composite (Vertise Flow/Kerr) compared with conventional resin composite with self-etching adhesive (Filtek Z250/3M ESPE and Clearfil SE Bond/Kuraray-Noritake). Material and MethodsA randomized, controlled, double-blind, split-mouth, two-arm clinical trial was conducted. Twenty-seven volunteers with third molars indicated for extraction received two deep class I restorations, one with each material. The morphology and immunohistochemical expression were measured at 15 days after the restorative procesures. The data were submitted to the Fisher`s Exct test (α=0.05). ResultsThrough morphological analysis, a slight disorganization of the odontoblastic layer was visualized, along with a slight inflammatory infiltrate in the VERT and CSEB groups (p< 0.05). In immunohistochemical analysis, TNF-alpha, MMP-9, TIMP-3 and COX-2 demonstrated more cases of positive pulp labeling. ConclusionsSelf-adhesive resin composite and conventional resin composite with a self-etching bonding agent promoted slight alterations in the dentin-pulp complex, indicating a repair ability and reversibility of the inflammatory process against aggressions of the adhesive restorative procedure. Key words:Immunohistochemistry, inflammation, randomized clinical trial, self-adhering composite, dentistry.

Comparing the pulp/tooth area ratio and dentin thickness of mandibular first molars in different age groups: A cone-beam computed tomography study.

Context:Mandibular first molar frequently requires endodontic treatment. Understanding age-related changes in pulp-dentin complex and root canal morphologies is essential for successful endodontic and restorative treatments.Aim:This study aimed to compare pulp/tooth area ratio (PTAR) and dentin thickness (DT) in mandibular first molars in different age groups through cone-beam computed tomography (CBCT) imaging.Subjects and Methods:One hundred CBCT images of mandibular first molar were divided into five groups; age 20–29, 30–39, 40–49, 50–59, and 60 years old and older. Axial images were used to determine PTAR at Level A (furcation), Level B (between Levels A and C), and Level C (half distance between the furcation and apex of the root). The minimum DT of the distal wall of mesiobuccal (MB) and mesiolingual (MLi) canal and mesial wall of distal canal at 2 and 3 mm under the furcation was measured.Statistical Analysis Used:Analysis of variance was used to determine differences among age groups.Results:PTAR was determined to reduce as age increases, showing a significant difference among the age groups at Levels A, B, and C of both roots (P < 0.05). The minimum DT was found to increase with age, demonstrating a significant difference among the age groups of MB and MLi canal at 2 and 3 mm (P < 0.05). No statistically significant difference was observed in the mesial DT of distal canal.Conclusions:The reduction of PTAR and the increasing DT were confirmed with advanced age.

Pediatric regenerative endodontics

The vitality of dentin–pulp complex is fundamental to the life of the tooth and is a priority for targeting clinical management strategies. One novel approach to restore tooth structure is based on biology: regenerative endodontic procedure by application of tissue engineering. Regenerative endodontics is an exciting new concept that seeks to apply the advances in tissue engineering to the regeneration of the pulp–dentin complex. The basic logic behind this approach is that patient-specific tissue-derived cell populations can be used to functionally replace integral tooth tissues. The development of such “test tube teeth” requires precise regulation of the regenerative events to achieve proper tooth size and shape, as well as the development of new technologies to facilitate these processes. This article provides a general review of literature and a case report on the concept of revascularisation and its application in endodontics, providing an insight into the new developmental approaches on the horizon.

Acidic Monetite Complex Paste with Bleaching Property for In-depth Occlusion of Dentinal Tubules.

BackgroundDentin hypersensitivity (DH) is a common dental clinical condition presented with a short and sharp pain in response to physical and chemical stimuli. Currently no treatment regimen demonstrates long-lasting efficacy in treating DH, and unesthetic yellow tooth color is a concern to many patients with DH.AimTo develop a bi-functional material which can occlude dentinal tubules in-depth and remineralize dentin for long-lasting protection of the dentin–pulp complex from stimuli and bleach the tooth at the same time.MethodsA mixture containing CaO, H3PO4, polyethylene glycol and H2O2 at a specific ratio was mechanically ground using a planetary ball. The mineralizing complex paste was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Dentin was exposed to the synthesized paste for 8 h and 24 h in vitro. The mineralizing property was evaluated using SEM and microhardness tests. Red tea-stained tooth slices were exposed to the synthesized paste for 8 h and 24 h in vitro. The bleaching effect was characterized by a spectrophotometer.ResultsThe complex paste had very a fine texture, was injectable, and had a gel-like property with 2.6 (mass/volume) % H2O2 concentration. The X-ray diffraction pattern showed that the inorganic phase was mainly monetite (CaHPO4). The mineralizing complex paste induced the growth of inorganic crystals on the dentin surface and in-depth occlusion of dentin tubules by up to 80 μm. The regenerated crystals were integrated into the dentin tissue on the dentin surface and the wall of dentinal tubules with a microhardness of up to 126 MPa (versus 137 Mpa for dentin). The paste also bleached the stained dental slices.ConclusionThe mineralizing complex paste is a promising innovative material for efficient DH management by remineralizing dentin and in-depth occlusion of dentin tubules, as well as tooth bleaching.

Pulp liner materials in selective caries removal: study protocol for a randomised controlled trial

IntroductionThe literature shows that selective carious tissue removal (SCTR) decreases the number and diversity of bacteria, stops the caries process and reduces the risk of pulp exposure. However, no consensus...