Odontoblast Cell Research Articles

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.

Odontoblast cell death induces NLRP3 inflammasome-dependent sterile inflammation and regulates dental pulp cell migration, proliferation and differentiation.

To investigate the ability of dead odontoblasts to initiate NLRP3 inflammasome-dependent sterile inflammation and to explore the effect on dental pulp cell (DPCs) migration, proliferation and odontogenic differentiation. Odontoblast-like cells were subjected to freezing-thawing cycles to produce odontoblast necrotic cell lysate (ONCL). DPCs were treated with ONCL to assess proliferation and migration. THP-1 differentiated macrophages stimulated with ONCL and live cell imaging and western blotting were used to assess NLRP3 inflammasome activation. Cytokines were measured with multiplex arrays and ELISA. qPCR, alkaline phosphatase and Alizarin red assays were used to assess odontogenic differentiation of DPCs. Data were analysed using the t-test or anova followed by a Bonferroni post hoc test with the level of significance set at P≤0.05. ONCL induced migration and proliferation of DPCs. Treatment of THP-1 macrophages with ONCL resulted in the release of the inflammatory cytokines IL-1β, IL-6, IL-8, TNFα, IFN-γ, CCL2 and angiogenic growth factors, angiogenin and angiopoietin. This inflammatory response was associated with activation of NFκB, p38MAPK and NLRP3 inflammasome. To confirm that ONCL induced inflammatory response is NLRP3 inflammasome-dependent, treatment with a caspase-1 inhibitor and a specific NLRP3 inhibitor significantly reduced IL-1β release in THP-1 macrophages (P=0.01 and 0.001). Inflammasome activation product, IL-1β, induced odontogenic differentiation of DPCS as evident by the increase in odontogenic genes expression DMP-1, RUNX-2, DSPP and SPP, alkaline phosphatase activity and mineralization. Dead odontoblasts induced NLRP3 inflammasome-dependent sterile inflammation and activated the migration, proliferation and differentiation of DPCs.

Gestational protein restriction alters the RANKL/OPG system in the dental germ of offsprings

ObjectiveEvaluate the dentinogenesis in the offspring of rats submitted to gestational protein restriction (GPR). Design: The offspring were evaluated at the 21st day of gestation (21 dG). Assessments were made of morphological parameters and the RANKL/OPG system - bone tissue maturation markers - in the upper incisor tooth germ. Pregnant 10-week-old female Wistar rats were divided into normal protein (NP, 17% casein, n = 5) and low protein (LP, 6% casein, n = 5) diet groups. At 21 dG, the offspring maxillae were collected for histomorphometric and immunohistochemical analyses. Results: The LP group showed decreased thickness of the dentin and odontoblast cell layers on the tooth germ. GPR led to decreased OPG expression and increased RANKL expression in the incisor germ. Conclusion: The results suggested that gestational protein restriction altered odontoblast RANKL/OPG expression and decreased dentin matrix deposition and thickness in tooth development.

GuttaFlow® Bioseal Cytotoxicity Assessment: In Vitro Study.

The sealers used for root canal treatment should be biocompatible for the peri-radicular tissues, to evaluate the cytotoxic effects of GuttaFlow® bioseal sealer and to compare them with AH26® epoxy resin. Culture media were conditioned with the GuttaFlow® bioseal and AH26® pellets. MDPC-23 odontoblast cell cultures were treated with conditioned medium and serial dilutions. To evaluate the metabolic activity and cellular viability, the MTT and SRB assays were performed. To determine the production of reactive oxygen species, the DHE and DCF-DA probes were used. Cell cycle and cell-death types were assessed by cytometry, and to evaluate the mineralization capacity, the Alizarin Red S coloration was used. Statistical analysis was performed using analysis of variance (ANOVA) when normality was found and Kruskal-Wallis on the opposite case. For the comparison with normality values, the Student t-test was used. Cells exposed to the GuttaFlow® bioseal conditioned medium maintained high metabolic activities, except at higher concentrations. Likewise, viability was maintained, but a significant decrease was observed after exposure to the highest concentration (p < 0.001), associated with cell death by late apoptosis and necrosis. When cell cultures were exposed to AH26®, metabolic activity was highly compromised, resulting in cell death. An imbalance in the production of peroxides and superoxide anion was observed. GuttaFlow® bioseal showed higher biocompatibility than AH26®.

The effect of low intensity pulsed ultrasound on dentoalveolar structures during orthodontic force application in diabetic ex-vivo model

ObjectiveThis study aimed to investigate the effect of the low intensity pulsed ultrasound (LIPUS) on the dentoalveolar structures during orthodontic force application in ex-vivo model using mandible slice organ culture (MSOC) of diabetic rats. Design18 male Wistar rats with a mean weight (275 g) were randomly divided into three main groups: 1) normal rats, 2) Insulin treated diabetic rats, and 3) diabetic rats. Diabetes mellitus (DM) was induced by streptozotocin. Four weeks later, rats were euthanized, mandibles were dissected, divided into 1.5-mm slices creating mandible slice organ cultures (MSOCs). MSOCs were cultured at 37 °C in air with 5 % CO2. The following day, orthodontic spring delivering a 50-g of force was applied to each slice. In each group, rats were randomly assigned to 2 subgroups; one received 10 min of LIPUS daily and the other was the control. Culture continued for 7 days, and then the sections were prepared for histological and histomorphometric analysis. ResultsFor all study groups (Normal, Insulin Treated Diabetic and Diabetic), LIPUS treatment significantly increased the thickness of predentin, cementum, and improved bone remodeling on the tension side and increased odontoblast, sub-odontoblast, and periodontal ligaments cell counts and bone resorption lacunae number on the compression side. ConclusionsApplication of LIPUS treatment for 10 min daily for a week enhanced bone remodeling and repair of cementum and dentin in normal as well as diabetic MSOCs.

R-Spondin 2 Induces Odontogenic Differentiation of Dental Pulp Stem/Progenitor Cells via Regulation of Wnt/β-Catenin Signaling.

Odontoblast cells generated from human dental pulp stem/progenitor cells (hDPSCs) secrete reparative dentin in responds to an injury. Endogenous Wnt signaling is also activated during this process, and these Wnt-activated cells are responsible for the following repair response. R-spondin 2 (Rspo2) is a potent stem cell growth factor, which strongly potentiates Wnt/β-catenin signaling and plays a vital role in cell differentiation and regeneration. However, the role of Rspo2 during odontoblast differentiation in hDPSCs has not yet been completely understood. This study investigated the effects of Rspo2 on hDPSCs to provide therapeutic insight into dentin regeneration and reparative dentin formation. HDPSCs were extracted from human molars or premolars. Immunofluorescence staining and flow cytometric analysis were used to detect the mesenchymal stem cell markers in hDPSCs. EdU assay and Cell Counting Kit-8 (CCK-8) were performed to explore cell proliferation. The odontogenic differentiation levels were determined by measuring the mRNA and protein expression of DSPP, DMP-1, ALP, and BSP. Immunofluorescence staining was performed to detect the localization of β-catenin. The biological effects of Rspo2 on hDPSCs was investigated using the Lentivirus-based Rspo2 shRNA and recombined human Rspo2 (rhRspo2). Recombined human DKK-1 (rhDKK-1) and recombined human Wnt3a (rhWnt3a) were used for further investigation. The cells generated from human dental pulp expressed mesenchymal stem cell markers Vimentin, Stro-1, Nestin, C-kit, CD90, and CD73, while were negative for CD3, CD31, and CD34. The mRNA expression levels of the odontogenic-related genes DSPP, DMP-1, ALP, and BSP were upregulated in the rhRspo2 treated cells. Silencing Rspo2 suppressed the proliferation and differentiation of the hDPSCs. Blockade of Wnt signaling with DKK-1 inhibited Rspo2-induced activation of Wnt/β-catenin signaling and cell differentiation. The combined use of rhWnt3a and rhRspo2 created a synergistic effect to improve the activation of Wnt/β-catenin signaling. Rspo2 promoted the proliferation and odontogenic differentiation of hDPSCs by regulating the Wnt/β-catenin signaling pathway.

Mesenchymal Bmp7 Controls Onset of Tooth Mineralization: A Novel Way to Regulate Molar Cusp Shape.

Investigating the molecular basis for tooth shape variation provides an important glimpse into the evolution of tooth function. We recently showed that loss of mesenchymal BMP7 is sufficient to alter morphology and function of the toothrow. Here we report on the underlying mechanism. Expression of mesenchymal Bmp7 is observed at sites where mineralization is initiated, in tooth cusps of developing molars. Neural crest-specific deletion of Bmp7 (Bmp7ncko) resulted in a complete lack of dentin/enamel formation at birth, the time when mineralization is normally initiated in the upper molars, similar to what was observed in Bmp2ncko mice. Unlike loss of Bmp2, loss of Bmp7 did not affect odontoblast polarization and did not significantly alter the levels of pSmad1/5/8, but almost completely abolished canonical Wnt signaling in (pre)-ameloblasts. Tooth mineralization resumed with a 48-h delay allowing for additional mesenchymal proliferation. Enamel volume was still reduced at P4 and P8, but was comparable in erupted teeth, which were broader and had altered cusp shapes. Tooth eruption was also delayed. Overall, enamel appeared inconspicuous, although some structural changes along with reduced mineral density could be observed. Loss of Bmp7 led to an increase in mesenchymal Bmp6 suggesting an interplay between Bmp6 and Bmp7 in the regulation of mineralization initiation. Our findings show that regulation of the onset of tooth mineralization is a hitherto unsuspected mechanism controlling tooth shape variation. Initiation of tooth mineralization is regulated by a complex epithelial-mesenchymal Bmp/Wnt-signaling network to which Bmp7 contributes. This network is separate and independent of the Bmp2-signaling network regulating odontoblast cell polarization. From an evolutionary perspective, addition of Bmp7 as initiator of tooth mineralization might be akin to an upgrade of an existing computer operating system. While not essential, it provides obviously sufficient advantage warranting its evolutionary incorporation.

RETRACTED: Products of dentin matrix protein-1 degradation by interleukin-1β-induced matrix metalloproteinase-3 promote proliferation of odontoblastic cells.

RETRACTED: Products of dentin matrix protein-1 degradation by interleukin-1β-induced matrix metalloproteinase-3 promote proliferation of odontoblastic cells.

Gelatinases Cleave Dentin Sialoprotein Intracellularly.

Dentin sialoprotein (DSP), the NH2-terminal fragment of dentin sialophosphoprotein (DSPP), is essential for dentin formation and further processed into small fragments inside the odontoblasts. Gelatinases, including matrix metalloproteinases 9 (MMP9) and MMP2, were able to cleave DSP(P) in tooth structures. We hypothesized that gelatinases may also cleave DSP intracellularly in the odontoblasts. In this study, the co-expression and physical interaction between DSP and gelatinases were proved by double immunofluorescence and in situ proximity ligation assay (PLA). Intracellular enzymatic activity of gelatinases was verified by gelatin zymography and in situ zymography. To confirm whether DSP was cleaved by active gelatinases intracellularly, lysates of wild-type (WT) odontoblastic cells treated with a MMP2 inhibitor or a MMP9 inhibitor or a MMP general inhibitor and of Mmp9–/– odontoblastic cells were analyzed by western blotting. Compared with the WT odontoblastic cells without inhibitor treatment, all these groups exhibited significantly higher ratios of high molecular weight to low molecular weight band density. FURIN was verified to be co-localized and physically interacted with MMP9 by double immunofluorescence and in situ PLA. The ratio of proMMP9 to activated MMP9 inside the odontoblastic cells were increased when function of endogenous FURIN was inhibited. And overexpressed proMMP9 was intracellularly cleaved by FURIN in the HEK293E cells, which was completely blocked by the mutation of proMMP9 with R96TPR99 substituted by A96AAA99. Taken together, these results indicate that DSP is intracellularly processed by gelatinases, and FURIN is involved in the intracellular activation of proMMP9 through cleavage of its R96TPR99 motif.

Controlled release of odontogenic exosomes from a biodegradable vehicle mediates dentinogenesis as a novel biomimetic pulp capping therapy

Mineralized enamel and dentin provide protection to the dental pulp, which is vital tissue rich with cells, vasculature, and nerves in the inner tooth. Dental caries left untreated threaten exposure of the dental pulp, providing facile access for bacteria to cause severe infection both in the pulp and systemically. Dental materials which stimulate the formation of a protective dentin bridge after insult are necessary to seal the pulp chamber in an effort to maintain natural dentition and prevent pulpal infection. Dental materials to date including calcium hydroxide paste, mineral trioxide aggregate, and glass ionomer resin, are used with mixed results. Herein we exploited the cell-cell communicative properties of exosomes, extracellular vesicles derived from both mineralizing primary human dental pulp stem cells (hDPSCs) and an immortalized murine odontoblast cell line (MDPC-23), to catalyze the formation of a reactionary dentin bridge by recruiting endogenous stem cells of the dental pulp, through an easy-to-handle delivery vehicle which allows for their therapeutic controlled delivery at the pulp interface. Exosomes derived from both hDPSCs and MDPCs upregulated odontogenic gene expression and increased mineralization in vitro. We designed an amphiphilic synthetic polymeric vehicle from a triblock copolymer which encapsulates exosomes by polymeric self-assembly and maintains their biologic integrity throughout release up to 8–12 weeks. The controlled release of odontogenic exosomes resulted in a reparative dentin bridge formation, superior to glass-ionomer cement alone in vivo, in a rat molar pulpotomy model after six weeks. We have developed a platform for the encapsulation and controlled, tunable release of cell-derived exosomes, which maintains their advantageous physiologic properties reflective of the donor cells. This platform is used to modulate downstream recipient cells towards a designed dentinogenic trajectory in vitro and in vivo. Additionally, we have demonstrated the utility of an immortalized cell line to produce a high yield of exosomes with cross-species efficacy.

Mussel‐Inspired Biocoating for Improving the Adhesion of Dental Pulp Stem Cells in Dental Pulp Regeneration

Dental pulp engineering possesses a promising perspective to replacing lost pulp in the root canal and restoring its functions. Stable adhesion of dental pulp stem cells (DPSCs) on the root canal dentin wall is a key element required for reconstruction of a functional odontoblast layer in dental pulp regeneration. To address this challenge, dopamine-modified hyaluronic acid (DA-HA) is coated on dentin to obtain a stable adhesion of DPSCs. The dopamine segment provides adhesion ability to the coating, and the hyaluronic acid increases the biocompatibility. The results show that DPSCs can adhere on the DA-HA coated dentin slice better than those without coating. Simultaneously, DPSCs proliferation can be further promoted on the prepared coating. Therefore, the DA-HA coating may provide a possible way to immobilize odontoblast cell onto dentin surface for pulp regeneration.

Viabilities of Odontoblast Cells Following Addition of Haruan Fish in Calcium Hydroxide

Background: Haruan fish (Channa striatus) extract (HFE) contains all the essential amino acids and fatty acids that it is believed to have therapeutic value, accelerate wound healing and anti-inflammation. This study was aimed to examine the viability of odontoblast MDPC-23 cell lines following the addition of HFE in toxin of Lactobacillus sp. and/or Ca(OH)2. Materials and Methods: Firstly, to find antiproliferative effective doses, MDPC-23 cells were treated with HFE. The cell viability was measured by MTT assay on 24 h after the last treatment. While cell death was induced by addition toxin and/or Ca(OH)2 following adding antiproliferative effective doses of HFE (25.0; 50.0; and 100 µg/mL). Untreated cells were used as control. Result: Adding of HFE at range 25.0 till 100 µg/mL increased the MDPC-23 cells viability. MDPC-23 on toxin and/or Ca(OH)2 reported decrease the viability of cells, while supplemented with HFE significantly increase in cell viability compared to untreated cell (p&lt;0.05). Conclusion: HFE effectively increased the viability of odontoblast MDPC-23 cells and has the potency to be used together to avoid the negative side effect of (CaOH)2 as a capping agent.&#x0D; BACKGROUND: Haruan fish (Channa striatus) extract (HFE) contains all the essential amino acids and fatty acids that it is believed to have therapeutic value, accelerate wound healing, and anti-inflammation.&#x0D; AIM: This study was aimed to examine the viability of odontoblast MDPC-23 cell lines following the addition of HFE in toxin of Lactobacillus sp. and/or Ca(OH)2.&#x0D; MATERIALS AND METHODS: First, to find antiproliferative effective doses, MDPC-23 cells were treated with HFE. The cell viability was measured by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide assay on 24 h after the last treatment, while cell death was induced by addition toxin and/or Ca(OH)2 following adding antiproliferative effective doses of HFE (25.0; 50.0; and 100 μg/mL). Untreated cells were used as control.&#x0D; RESULTS: Adding of HFE at range 25.0 until 100 μg/mL increased the MDPC-23 cells viability. MDPC-23 on toxin and/or Ca(OH)2 reported decrease the viability of cells, while supplemented with HFE significantly increase in cell viability compared to untreated cell (p &lt; 0.05).&#x0D; CONCLUSION: HFE effectively increased the viability of odontoblast MDPC-23 cells and has the potency to be used together to avoid the negative side effect of (CaOH)2 as a capping agent.

Enhancer of zeste homolog 2 affects dental pulp inflammation by regulating macrophage chemotaxis

OBJECTIVE To investigate the expression changes of the epigenetic regulator enhancer of zeste homolog 2 (EZH2) during pulp inflammation and the effect of EZH2 on macrophages migration. METHODS Rat dental pulp was stimulated with 10 g/L lipopolysaccharide (LPS) to establish a model of rat pulpitis at different stages of inflammation. Immunohistochemical staining was used to detect the expression changes of EZH2 during the progression of pulp inflammation. Immunofluorescence double staining was used to detect the expression of EZH2, CD68 and their colocalization. To screen the appropriate concentration of EZH2 recombinant protein to stimulate hDPCs and human leukaemia-derived monocytic cell line (THP-1) cells, the effects of different concentrations (1, 10, 20, 40, and 100 μg/L) of EZH2 recombinant protein on proliferation of human dental pulp cells (hDPCs) and human monocyte cell line THP-1 were detected by cell counting kit-8 (CCK-8). Transwell migration assay was used to detect the effect of supernatants of hDPCs treated with EZH2 recombinant protein on the migration of THP-1 cells. RESULTS HE staining results showed that in the model of rat pulp inflammation induced by LPS, with the prolongation of LPS stimulation, the inflammation response of pulp gradually increased. Immunohistochemical results showed that EZH2 expression decreased within 8 h of LPS-induced dental pulp inflammation; but after 1, 3, and 7 d of stimulation, EZH2 expression gradually increased with the extension of the stimulation time. As for the normal rat dental pulp tissue, the positive expression of EZH2 was scattered in the odontoblast cell layer and the pulp proper. Compared with the control group, LPS stimulated the expression of EZH2 and CD68 in the infected dental pulp, and the colocalization of EZH2 and CD68 could be detected in macrophages. The results of CCK-8 suggested that the appropriate concentration of EZH2 recombinant protein to stimulate hDPCs and THP-1 cells was 20 μg/L. Transwell cell migration assay confirmed that compared with the supernatant of EZH2 untreated HDPCs group, the supernatant of EZH2treated hDPCs significantly promoted macrophage chemotaxis. CONCLUSION EZH2 is involved in the development of pulpitis and promotes the chemotaxis of macrophages, which suggests that EZH2 may play an important regulatory role in the development of pulp inflammation.

Induction of Cardiomyogenesis in Stem Cells Isolated from Human Exfoliated Deciduous Teeth

Background: The natural transition from neonatal deciduous teeth to adult permanent teeth is a physiological phenomenon. Miura et al. reported the isolation and characterization of stem cells from the pulp of human exfoliated deciduous teeth (SHED). The great majority of current stem cell therapies use human adult stem cells. Since adult stem cells are multi-potent. SHED have demonstrated to have the capability to differentiate into osteogenic and odontogenic cells, adipocytes, and neural cells. When transplanted in immunocompromised mice, SHED were able to form bone. In addition, SHED have been able to differentiate into functional odontoblast and angiogenic endothelial cells. Aims and Objective: There are two objectives in our study; First, we want to confirm that SHED cells differentiate into osteogenic and neurotic cells. Second, we shall also examine whether SHED stem cells can also differentiate into cardiomyocytes. Material and Method: SHED stem cells are subjected to cardiomyogenic, neurogenic, and osteogenic induction treatment. The treated cells are the subjected to real time PCR and mmuno-histochemical analysis. The presence of calcium deposits with Alizarin Red S staining for SHED cells treated with osteogenic media was used to confirm osteogenic differentiation. Results: Our study confirmed that SHED cells differentiate into osteogenic and neurotic cells. For the first time we showed that SHED cells can also differentiate into cardiomyocytes. Conclusion: Due to their potentials and its neural crest origin, SHED are an ideal stem cell source for tissue regeneration.

Effects of diode laser irradiation on dental pulps in rats.

To evaluate the effects of different power densities of diode laser on dental pulps in rats. In this study, we used the maxillary central incisors (n=80) of the 40 adult male Wistar albino rats. Rats were randomly divided into four groups according to power densities of diode laser (n=10). Histopathological changes in pulp and height of odontoblast layer were examined . All data were compared statistically using Mann‒Whitney U (Bonferroni) test, p<0.05. G2 displayed slight histolopathologic alterations such as odontoblast cell disorganization and irregularities in cell extensions. Alterations were more prominent in the G3 than G2. Although the lowest odontoblast layer was measured in the G4, the difference in height of odontoblast layer among the groups was not found to be statistically significant. It was concluded that the use of diode laser caused changes at the cellular level in histological examination and may induce the formation of tertiary dentin by influencing the secretory activity of odontoblasts. As long as used in accordance with the recommended procedure, the diode laser can be safely used in dental hard tissues (Tab. 1, Fig. 4, Ref. 15).

Retinoic Acid Signaling and the Zebrafish Dentition During Development and Evolution.

Explaining how the extensive diversity in form of vertebrate teeth arose in evolution and the mechanisms by which teeth are made during embryogenesis are intertwined questions that can merit from a better understanding of the roles of retinoic acid (RA) in tooth development. Pioneering studies in rodents showed that dietary vitamin A (VA), and eventually RA (one of the major active metabolites of VA), are required for proper tooth formation and that dentin-forming odontoblast cells seem to be especially sensitive to changes in RA levels. Later, rodent studies further indicated that RA signaling interactions with other cell-signaling pathways are an important part of RA's actions in odontogenesis. Recent investigations employing zebrafish and other teleost fish continued this work in an evolutionary context, and specifically demonstrated that RA is required for the initiation of tooth development. RA is also sufficient in certain circumstances to induce de novo tooth formation. Both effects appear to involve cranial-neural crest cells, again suggesting that RA signaling has a particular influence on odontoblast development. These teleost studies have also highlighted both evolutionary conservation and change in how RA is employed during odontogenesis in different vertebrate lineages, and thus raises the possibility that developmental changes to RA signaling has led to some of the diversity of form seen across vertebrate dentitions. Future progress in this area will come at least in part from expanding the species examined to get a better picture of how often RA signaling has changed in evolution and how this relates to the evolution of dental form.

Caffeic Acid Phenethyl Ester (CAPE) Induces VEGF Expression and Production in Rat Odontoblastic Cells.

Caffeic acid phenethyl ester (CAPE), the main component of propolis, has various biological activities including anti-inflammatory effect and wound healing promotion. Odontoblasts located in the outermost layer of dental pulp play crucial roles such as production of growth factors and formation of hard tissue termed reparative dentin in host defense against dental caries. In this study, we investigated the effects of CAPE on the upregulation of vascular endothelial growth factor (VEGF) and calcification activities of odontoblasts, leading to development of novel therapy for dental pulp inflammation caused by dental caries. CAPE significantly induced mRNA expression and production of VEGF in rat clonal odontoblast-like KN-3 cells cultured in normal medium or osteogenic induction medium. CAPE treatment enhanced nuclear factor-kappa B (NF-κB) transcription factor activation, and furthermore, the specific inhibitor of NF-κB significantly reduced VEGF production. The expression of VEGF receptor- (VEGFR-) 2, not VEGFR-1, was up regulated in KN-3 cells treated with CAPE. In addition, VEGF significantly increased mineralization activity in KN-3 cells. These findings suggest that CAPE might be useful as a novel biological material for the dental pulp conservative therapy.

Retraction: Interleukin-1β-Induced Autophagy-Related Gene 5 Regulates Proliferation of Embryonic Stem Cell-Derived Odontoblastic Cells.

Retraction: Interleukin-1β-Induced Autophagy-Related Gene 5 Regulates Proliferation of Embryonic Stem Cell-Derived Odontoblastic Cells.

English

BACKGROUND Removal of third molars is one of the most commonly used procedures in dental surgery. Awareness of the pattern of impaction and associated pathologies can prevent a number of specific problems. The purpose of this study was to evaluate the incidence of third molar tooth and its histopathology in patients referred to the dental clinic of Ilam University of Medical Sciences. METHODS This descriptive-analytic study was conducted on patients who for any reason complained of impacted third molar teeth. In this evaluation, 50 impacted teeth with normal follicular space were measured in panoramic radiography. Then, under local anaesthesia, follicle and tooth were removed by surgery and placed in a 10 formalin container. The specimens were stained with H & E after preparation in the lab. Then, the histological profile of the tooth and its pulp structure were studied. The hard tissue of the teeth was placed in a 5 nitric acid solution before cutting. Data obtained from this study were analysed using descriptive statistics (mean, standard deviation, percentage and frequency) and Fisher's exact test (chi-square) and software SPSS Ver.19. Significance is reported at p< 0.05. RESULTS Out of 50 dental follicles examined, 44 (22 cases) of pathologic changes showed that 20 had inflammation. Of these, 16 cases (32) were related to male patients and 34 cases (68) were related to female patients. The percentage of pathologic changes in the follicles obtained from female patients was 77.3 (17 cases) and in male patients (22.7) (n= 5) (p= 0.17). The age range was 19-40 years. The mean and standard deviation of the age of the patients was 26.7 +/- 1.5, most of them in the third decade of age. There was no statistically significant relationship between age and pathologic changes (p= 0.17). Of the examined cases, 32 follicles (64) were related to the maxilla and 18 of the follicles (36) were related to the jaw. Pathologic changes in maxilla were 18.1 (4 cases) and in lower mandible (81.9) (18 cases). There was no significant correlation between the location of follicles in third molar teeth and pathologic changes (p= 0.37). Comparing frequency of dental pulp cells include odontoblast, fibroblast and immune cells, there was no statistically significant difference, (p=0.610). CONCLUSIONS Pathologic changes related to aging in dental pulp and follicle of impacted wisdom tooth is inappreciable; remaining impacted wisdom tooth doesn't lead to clinical/pathologic problems in patients, but it is recommended to extract these teeth in young ages (below 35) so as to accelerate healing process and reduce surgery complications.

Immunolocalization of podoplanin/E11/gp38, CD44, and endomucin in the odontoblastic cell layer of murine tooth germs.

In this study, we attempted to localize the immunoreactivities of podoplanin/E11/gp38 and CD44, a counterpart possessing a high affinity to podoplanin/E11/gp38, as well as endomucin-immunoreactive blood vessels in the regions of odontoblast layers and the underlying sub-odontoblastic layers in murine tooth germs. Endomucin-reactive small blood vessels were scattered throughout the dental papillae of the tooth germs at postnatal day 1 but came to be localized close to the odontoblast/sub-odontoblastic layers until day 3. After postnatal day 5, small blood vessels were seen in odontoblast cell layers, while blood vessels with relatively larger diameters were seen forming in sub-odontoblastic layers. Immunoreactivities of podoplanin/E11/gp38 and CD44 were not detectable in the cells of dental papillae facing the inner enamel epithelium at postnatal day 1. However, at around postnatal days 3-5, podoplanin/E11/gp38 was localized in the odontoblast layer but not in the sub-odontoblastic layer, whereas CD44 was observed in the sub-odontoblastic layer but not in the odontoblast layer. The exclusive immunolocalization of podoplanin/E11/gp38 and CD44 in the odontoblast layers and sub-odontoblastic layers was seen after postnatal day 3 of the tooth germs, when the mesenchymal cells of dental papillae have already differentiated into mature odontoblasts at the cusp tip. Taken together, it seems likely that endomucin-reactive small blood vessels extended to the podoplanin/E11/gp38-positive odontoblast layers, whereas endomucin-reactive large blood vessels were already present in CD44-immmunopositive sub-odontoblastic layer, indicating the cellular regulation on the vascularization of endomucin-reactive endothelial cells during odontogenesis of the tooth germs.