Molar Pulp Research Articles

Novel co-initiators of polymerization: Cytotoxicity profile and modulation of inflammatory mediators in human dental pulp stem cells

ObjectivesThe aim of this study was to assess the cytotoxicity of novel polymerization co-initiators and their effect on cytokine release from human dental pulp stem cells (hDPSCs), comparing them with commonly used co-initiators. MethodsCells were isolated from the dental pulp of healthy human third molars. The new co-initiators, namely HDa1, HD4, HD1, and MHPTm, were evaluated and compared with the compounds dimethylaminoethyl amine benzoate (EDAB) and 2-(dimethylamino)ethyl methacrylate (DMAEMA). These compounds were diluted in dimethylsulfoxide (DMSO) at concentrations ranging from 1 to 8 mM. hDPSCs were seeded onto 96-well plates and incubated for 48 h. Subsequently, the cells were exposed to different concentrations of the co-initiators mentioned for 24 h. After this period, the culture medium was removed, and mitochondrial metabolism was evaluated using the MTT assay, while cytokine release (IL-1β, IL-6, IL-8, IL-10, TNF-α) was analyzed by the MAGPIX assay. Cells without exposure to the tested compounds served as controls. The data were analyzed using one-way ANOVA and Tukey’s test. ResultsThe compounds showed low toxicity, with 8 mM concentration causing the most significant reduction in mitochondrial metabolism. MHPTm was the most toxic co-initiator tested (compound bearing an amine functionality). All compounds up-regulated TNF-α, IL-10, IL-6, and IL-8, with HD4 exhibiting the most pronounced increase in IL-6 and IL-8. SignificanceThe newly proposed co-initiators demonstrated reduced impact on mitochondrial metabolism, comparable to some traditional co-initiators. Despite their lower toxicity, HD4 increased IL-6 and IL-8 release, suggesting its potential involvement in triggering an inflammatory reaction, particularly in the short term.

Histological evaluation of different concentrations of hyaluronic-acid-added zinc oxide eugenol on rat molar pulp.

Hyaluronic acid (HA), known for diverse properties, was investigated for its potential in dental pulp therapy. This study investigated the potential of HA in dental pulp therapy by examining the physical properties and effects of zinc oxide eugenol (ZOE) pulpotomy materials containing varying HA concentrations on rat molar teeth. In vitro tests assessed compressive strength and hardness of ZOE materials blended with HA (0.5%, 1%, 3%) and HA gels (0.54%, 0.8%). 120 samples, encompassing the control group, underwent compressive strength testing, while 60 samples were designated for hardness assessment. In vivo experiments on rat molars studied histological effects of HA-containing ZOE on dental pulp over 1week and 1month. Gels with HA concentrations of 0.5%, 1%, and 0.54% were used in pulpotomy on 22 rats. Each rat underwent the procedure on four teeth, with one tooth serving as a control, totaling 88 teeth subjected to the intervention. In the analyses, SPSS 22.0 was used and the significance level was set at P = 0.05. Findings showed that HA at 0.5% maintained compressive strength, but higher concentrations decreased mechanical properties significantly (P = 0.001). Histological assessments indicated better outcomes with lower HA concentrations in terms of odontoblast layer continuity (P = 0.005 at 1month) and pulp vitality (P = 0.001 at 1week and P = 0.018 at 1month). The study suggests HA holds promise for pulpotomy and regenerative endodontic treatments, but further research is needed to understand long-term clinical implications.

Hyaluronic acid as a pulpotomy material in primary molars: an up to 30 months retrospective study

BackgroundThe aim of this retrospective study was to determine the long-term clinical and radiographic success of our previous randomized clinical trial and to compare the success of hyaluronic acid, with the widely used formocresol and ferric sulphate agents.MethodsThis retrospective study is the extension of the 1-year survey of our randomized clinical trial that had compared the effectiveness of a hyaluronic acid pulpotomy over formocresol and ferric sulphate pulpotomies and included clinical and radiographic evaluations with a follow-up period of over 24 months for 44 children who applied to our clinic between May 2019 and September 2019. Long-term clinical and radiographic data were obtained from the periodic files of our department, wherein each tooth’s file was examined to identify any clinical and radiographic findings. Descriptive statistics and Pearson’s chi-square tests were used to evaluate the data. Statistical significance was considered as p < 0.05.ResultsThe clinical and radiographic success rates of the hyaluronic acid, formocresol, and ferric sulphate groups were not statistically different at > 24 months. None of the teeth in the hyaluronic acid group showed any clinical findings at > 24 months.ConclusionsHyaluronic acid pulpotomies exhibited comparable success rates to formocresol and ferric sulphate materials spanning over 24 months examinations. Because of convenient accessibility and applicability of hyaluronic acid, it may be recommended as a promising alternative medicament for pulpotomy treatments of primary molars. However, further long-term follow-up human studies are needed to better understand the effect of hyaluronic acid on the dental pulp of human primary molars.

A Combined Endodontic Management Approach in immature Permanent Molar tooth with Periapical Lesion: Case Report

Immature dental pulp, which has a highly cellular structure and a rich vascular nutrition system, is highly resistant to inflammation, In these teeth, determining the treatment option based on clinical and radiographic findings alone may result in the removal of diseased pulp tissue as well as vital pulp tissue. In order to increase the prognosis of these teeth, vital pulp treatments are highly recommended to preserve pulp vitality. By evaluating the condition of the root pulps of young permanent molars separately, it is possible to increase the prognosis of the tooth by combining regenerative endodontic treatment and pulpotomy treatment according to the condition of the pulps. In this case report, regenerative endodontic treatment and pulpotomy treatment were applied to different root canals of the first molar, which became necrotic before completing its maturation due to caries and had an apical lesion, and excellent healing was demonstrated. Key words: Biodentine, immature permanent teeth, periapical lesions, pulpotomy, regenerative endodontic treatment.

Comparison of the impact of orthodontic treatment on pulp volume in adolescents and adults

Objective: To compare the impact of orthodontic treatment on pulp volume in adolescents and adults. Methods: Cone-beam CT data of 62 patients undergoing orthodontic treatment at the Department of Orthodontics, Stomatological Hospital of Chongqing Medical University, from January 2019 to March 2022 were collected. Patients were divided into two age groups (31 patients in each group): adolescent group (aged 13-17, 17 males and 14 females) and adult group (aged 21-25, 12 males and 19 females). Pre-and post-treatment reconstructions of the pulp and dental tissues of upper first molars (UM1) and lower central incisors (L1) were performed. Measurements included pulp volume for UM1 (UM1 P) and L1 (L1 P), pulp chamber volume (UM1 PC) and root canal volume (UM1 RC) for UM1, root length for L1 (L1 RL), and mesiobuccal root length for UM1 (UM1 RL), as well as chamber heights at specific landmarks [the lengths from the central fossa fusion site to the roof of the pulp chamber (H1), the floor of the pulp chamber (H2), the nearest point of root divergence as well as crown-root bifurcation (H3), the farthest point of root divergence (H4), and the pulp chamber height (H5)] in UM1. Changes in these indices were calculated and analyzed using paired and independent sample t-tests for within-group and between-group differences, respectively. Pearson correlation was used to assess potential associations among H5, root length, and pulp volume changes. Results: Before and after orthodontic treatment, no significant difference was observed in the adult group for L1 P (t=-0.03, P=0.975), while significant differences were noted for UM1 P, UM1 PC, and UM1 RC (t=9.98, P<0.001; t=9.04, P<0.001; t=6.69, P<0.001). In the adolescent group, significant differences were found for both L1 P and UM1 P (t=2.25, P=0.029; t=6.30, P<0.001). After orthodontic treatment, the absolute value changes of UM1 P, UM1 PC, and L1 P in the adolescent group were (19.75±9.58), (15.07±7.65) and (1.89±6.29) mm3, respectively, and in the adult group were (13.33±9.41), (9.16±7.05) and (0.02±4.66) mm3, respectively (t=3.77, P<0.001; t=4.48, P<0.001; t=2.34, P=0.048). There was no significant absolute difference in the amount of UM1 RC between the two groups after orthodontic treatment (t=0.86, P=0.391). Before and after orthodontic treatment, the absolute value changes of L1 RL, H1 and H5 in the adolescent group were (0.54±0.41), (0.38±0.27) and (0.71±0.33) mm, respectively, and the absolute value changes in the adult group were (0.78±0.62), (0.26±0.20) and (0.57±0.28) mm, respectively (t=-2.43, P=0.017; t=2.96, P=0.004; t=2.57, P=0.011). Whereas no significant differences were observed for UM1 RL, H2, H3, and H4 (t=-0.85, P=0.400; t=0.43, P=0.669; t=-0.50, P=0.619; t=1.46, P=0.148). Additionally, significant correlations were found between changes in H5 and UM1 RL with UM1 P (r=0.35, P<0.001; r=0.19, P=0.030), but not between Changes in L1 RL and L1 P (r=0.11, P>0.05). Conclusions: The effect of orthodontic treatment on pulp volume in adolescents and adults were different.

Mechanism of Linagliptin on Stromal Cell-Derived Factor 1 and Vascular Endothelial Growth Factor Protein after Molar Pulp Revascularization in Rats

Mechanism of Linagliptin on Stromal Cell-Derived Factor 1 and Vascular Endothelial Growth Factor Protein after Molar Pulp Revascularization in Rats

Upper First and Second Molar Pulp Chamber Endodontic Anatomy Evaluation According to a Recent Classification: A Cone Beam Computed Tomography Study.

(1) The possibility of knowing information about the anatomy in advance, in particular the arrangement of the endodontic system, is crucial for successful treatment and for avoiding complications during endodontic therapy; the aim was to find a correlation between a minimally invasive and less stressful endodontic access on Ni-Ti rotary instruments, but which allows correct vision and identification of anatomical reference points, simplifying the typologies based on the shape of the pulp chamber in coronal three-dimensional exam views. (2) Based on the inclusion criteria, 104 maxillary molars (52 maxillary first molars and 52 maxillary second molars) were included in the study after 26 Cone Beam Computed Tomography (CBCT) acquisitions (from 15 males and 11 females). And linear measurements were taken with the CBCT-dedicated software for subsequent analysis. (3) The results of the present study show data similar to those already published about this topic. Pawar and Singh's simplified classification actually seems to offer a schematic way of classification that includes almost all of the cases that have been analyzed. (4) The use of a diagnostic examination with a wide Field of View (FOV) and low radiation dose represents an exam capable of obtaining a lot of clinical information for endodontic treatment. Nevertheless, the endodontic anatomy of the upper second molar represents a major challenge for the clinician due to its complexity both in canal shape and in ramification.

Chronic alcohol and nicotine consumption as catalyst for systemic inflammatory storm and bone destruction in apical periodontitis.

To assess the periapical alveolar bone pattern and the serum levels of proinflammatory cytokines, biochemical markers and metabolites in rats subjected to chronic alcohol and nicotine consumption and induced apical periodontitis. Twenty-eight male Wistar rats were divided into four groups: Control, Alcohol, Nicotine and Alcohol+Nicotine. The alcohol groups were exposed to self-administration of a 25% alcohol solution, while the other groups were given only filtered water. The nicotine groups received daily intraperitoneal injections of a nicotine solution (0.19 μL of nicotine/mL), whereas the other groups received saline solution. Periapical lesions were induced by exposing the pulps of the left mandibular first molars for 28 days. After euthanasia, the mandibles were removed and the percentage bone volume, bone mineral density, trabecular thickness, trabecular separation and trabecular number of the periapical bone were measured using micro-computed tomography images. Serum samples were collected for analysis of proinflammatory cytokines (IL-1β, IL-4, IL-6 and TNF-α), biochemical and metabolomic analysis. Statistical analysis was performed with a significance level of 5%. Nonparametric data were analysed using the Kruskal-Wallis test followed by Dunn's test, while one-way anova followed by Tukey's test was performed for parametric data. The groups exposed to alcohol or nicotine consumption exhibited an altered bone pattern indicating lower bone density and higher levels of IL-1β, IL-6 and TNF-α compared to the Control group (p < .05). Significant differences were observed among the groups in the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase, cholesterol, triglycerides, urea, creatinine, albumin, uric acid, bilirubin and calcium. Metabolomic analysis revealed significant differences in glycine, phosphocholine, lysine, lactate, valine, pyruvate and lipids (CH2 CH2 CO), n(CH2 ) and n(CH3 ). Most of these parameters were even more altered in the simultaneous consumption of both substances compared to single consumption. Alcohol and nicotine chronic consumption altered several metabolic markers, impaired liver and kidney function, increased the production of systemic proinflammatory mediators and harmed the periapical bone microarchitecture in the presence of apical periodontitis. The simultaneous consumption of alcohol and nicotine intensified these detrimental effects.

Non-Psychoactive Cannabinoid Modulation of Nociception and Inflammation Associated with a Rat Model of Pulpitis.

Despite advancements in dental pain management, one of the most common reasons for emergency dental care is orofacial pain. Our study aimed to determine the effects of non-psychoactive Cannabis constituents in the treatment of dental pain and related inflammation. We tested the therapeutic potential of two non-psychoactive Cannabis constituents, cannabidiol (CBD) and β-caryophyllene (β-CP), in a rodent model of orofacial pain associated with pulp exposure. Sham or left mandibular molar pulp exposures were performed on Sprague Dawley rats treated with either vehicle, the phytocannabinoid CBD (5 mg/kg i.p.) or the sesquiterpene β-CP (30 mg/kg i.p.) administered 1 h pre-exposure and on days 1, 3, 7, and 10 post-exposure. Orofacial mechanical allodynia was evaluated at baseline and post-pulp exposure. Trigeminal ganglia were harvested for histological evaluation at day 15. Pulp exposure was associated with significant orofacial sensitivity and neuroinflammation in the ipsilateral orofacial region and trigeminal ganglion. β-CP but not CBD produced a significant reduction in orofacial sensitivity. β-CP also significantly reduced the expression of the inflammatory markers AIF and CCL2, while CBD only decreased AIF expression. These data represent the first preclinical evidence that non-psychoactive cannabinoid-based pharmacotherapy may provide a therapeutic benefit for the treatment of orofacial pain associated with pulp exposure.

Three-dimensional morphometric analysis of maxillary and mandibular molars and bilateral correlation in North Indian population

The aim of this study was to evaluate and compare the anatomical landmarks of maxillary and mandibular molar pulp chambers and evaluate bilateral symmetry between contralateral molars using CBCT.CBCT scans of 200 molars from 157 patients were selected for the study. A total of nine measurements - A (Distance from the cusp tip to the roof of the pulp chamber) B (Distance from the cusp tip to the floor of the pulp chamber) C (Distance from the cusp tip to the furcation) D (Distance from the floor of the pulp chamber to the furcation) E (Distance from the roof of the pulp chamber to the furcation) F (Height of pulp chamber) A1(Distance from the central fossa to the roof of the pulp chamber) B1 (Distance from central fossa till the floor of pulp chamber) C1 (Distance from central fossa to furcation) were done. Statistical analysis was done using the ANOVA and Post hoc tests and statistical significance was set at p&amp;#60;0.05. Significant differences in maxillary and mandibular molars were noted in the measurements of- D, E, B and C1. Bilateral symmetry was also observed between the pairs of maxillary and mandibular molars.Maxillary first and second molars do not differ much from each other. However, mandibular first and second molars differed in various anatomic parameters from each other. Contralateral molars (maxillary and mandibular) pulp cavities, in general, exhibit matching symmetry in terms of their morphological and anatomical landmarks.

Single-cell transcriptome analysis reveals development atlas of mouse molar pulp cells

Objective: Single-cell RNA sequencing (scRNA-seq) was used to analyze the developing mouse molars, in order to construct a spatiotemporal development atlas of pulp cells, and further to reveal the developmental process and regulatory mechanism of tooth development. Methods: Ten mandibular first molars from C57BL/6 mice in postnatal day (PN) 0 and 3 were respectively dissected and digested to obtain single-cell suspensions. scRNA-seq was performed on 10× Genomics platform. PN 7 mouse molar scRNA-seq data were obtained from our previous study. PN 0, 3, and 7 scRNA-seq data were integrated for following analysis. The initial quality control, mapping and single cell expression matrix construction were performed by Cell Ranger. Quality control, standardization, dimensional reduction and cluster analysis were performed by using Seurat. Monocle was used to generate the pseudotime trajectory. Scillus was used to perform gene ontology analysis. In order to detect the spatiotemporal change of different population of pulp cells, the marker genes of each cluster were demonstrated by RNAscope in situ hybridization. Results: There were twenty-six cell clusters within mouse molars, which were identified as eight different cell types, including dental pulp cells, dental follicle cells, epithelial cells, immune cells, endothelial cells, perivascular cells, glial cells and erythrocytes. We further re-clustered and analyzed dental pulp cells. Cluster 0 were mature pulp cells, which located at the upper portion of crown. The main functions of cluster 0 were osteogenesis and extracellular structure organization. Cluster 1 were apical papilla cells, which located at the apical part of roots, whose main functions were extracellular structure organization and organ development. Cluster 2 were cycling cells, which were actively proliferated, resided in the lower portion of the crown. Cluster 3 and 4 were preodontoblasts and odontoblasts, respectively. Their functions were closely related to biomineralization. The proportion of mature pulp cells increased with the development process, while the proportion of cycling cells and odontoblast lineage decreased. According to the expression pattern of marker genes of each cluster, we constructed a cell atlas of dental pulp. Pseudotime trajectory analysis found there were two development trajectories within dental pulp. They both started from SPARC related modular calcium binding 2 (Smoc2)+ dental papilla cells, then went through DNA topoisomerase Ⅱ alpha (Top2a)+ cycling cells, and finally divided into coxsackie virus and adenovirus receptor (Cxadr)+ mature pulp cells or dentin sialophosphoprotein (Dspp)+ odontoblasts two lineages. Conclusions: scRNA-seq could fully discover the intercellular heterogeneity of cells on transcriptome level, which provides a powerful tool to study the process and regulatory mechanism of organ development.

Concentrated growth factor combined with iRoot BP Plus promotes inflamed pulp repair: an in vitro and in vivo study

BackgroundPlatelet concentrates combined with calcium silicate cements may promote reparative dentin formation. However, few studies have reported their effect on dental pulp inflammation. This study aimed to evaluate the effects of concentrated growth factor (CGF) combined with iRoot BP Plus on inflammatory human dental pulp stem cells (hDPSCs) in vitro and inflamed pulp in rats in vivo.MethodsThe proliferation of LPS-stimulated hDPSCs treated with 50% CGF with/without 25% iRoot BP Plus was evaluated using Cell Counting Kit-8 on days 1, 4 and 7. The expression of genes associated with inflammation on day 1 and differentiation on day 14 was analysed by real-time polymerase chain reaction. The exposed pulp of rat maxillary molars was injected with 10 mg/mL LPS and directly capped with CGF membrane with/without iRoot BP Plus extract for 1, 7 and 28 days. The teeth were subjected to histologic analyses and immunohistochemistry.ResultsThe proliferation rates of the inflammatory hDPSCs after the combination treatment were significantly higher than those after the other treatments on days 4 and 7 (P < 0.05). IL-1β, IL-6, and TNF-α levels were increased in inflammatory hDPSCs but decreased after treatment with CGF combined with iRoot BP Plus extract, whereas IL-4 and IL-10 showed the opposite expression patterns. Expression of the odontogenesis-related genes OCN, Runx2, and ALP was dramatically enhanced by combined treatment with CGF and iRoot BP Plus extract. In rat pulp, the average inflammation scores of the CGF and CGF-iRoot BP Plus groups significantly decreased in comparison with those of the LPS group (P < 0.05), and the CGF-iRoot BP Plus group had more reparative dentin than the CGF and BP groups. Immunohistochemical staining showed fewer M1 macrophages on day 1 and more M2 macrophages on day 7 in the CGF-iRoot BP Plus group than in the other groups.ConclusionsThe combination of CGF and iRoot BP Plus showed a synergistic effect on anti-inflammatory potential and promoted greater pulp healing than CGF or iRoot BP Plus alone.

Co-initiators of polymerization can modulate the inflammatory cytokine release without major cytotoxic effects in human dental pulp cells.

To evaluate the cytotoxicity of co-initiators of polymerization and its influence on cytokine release from human dental pulp cells (hDPCs). Cells were isolated from the dental pulp of sound human third molars. The co-initiators dimethylaminoethyl amine benzoate-(EDAB), 2-(dimethylamino)ethyl methacrylate (DMAEMA); 2-Ethylhexyl 4-(dimethylamino)benzoate (EHA) and bis(4-methyl phenyl)iodonium hexafluorophosphate (BPI) were diluted in dimethylsulfoxide (DMSO) at different concentrations. In this way, experimental groups and one control (without treatment) were obtained. hDPCs (10 × 104 cell per well) were seeded on 96 well plates and incubated at 37°C and 5% CO2 for 48 h. After this, the cells were exposed to different concentrations of co-initiators cited for 24 h. After this time, the culture medium was removed, and the mitochondrial metabolism was evaluated by MTT assay, cell death by flow cytometry, and cytokine released (IL-1β, IL6, IL-8, IL-10, and TNF-α) was analyzed by MAGPIX assay. The data were analyzed by ANOVA one-way and Tukey's test. EHA, DMAEMA, and EDAB did not reduce the mitochondrial metabolism. BPI presented high toxicity with remarkable reduction (80%) after exposure to 1 mM. The cell death of all test groups was similar to control. After 24 h treatment, the IL-8 was up-regulated by all compounds, while IL-6 was upregulated after exposure to EHA and downregulated after DMAEMA stimulation. BPI, EHA, EDAB, and DMAEMA can trigger an initial inflammatory response, upregulating the IL-8 secretion in hDPCs in a compound-concentration-dependent manner; however, this was not accompanied by major cytotoxic effects at cell death or mitochondrial-metabolism levels.

Age-Related Differences in Side Walls of Maxillary First Molar Pulp Cavities in Japanese Using Micro-Computed Tomography

Age-Related Differences in Side Walls of Maxillary First Molar Pulp Cavities in Japanese Using Micro-Computed Tomography

Influence of Direct Pulp Capping with Calcium Hydroxide and Mineral Trioxide Aggregate on Systemic Oxidative Stress in Rats

Abstract Direct pulp capping is a procedure where materials are placed on exposed vital pulp tissue in order to stimulate reparative dentinogenesis and preserve pulp vitality. Carious pulp exposure and direct pulp capping are usually accompanied by pulp inflammation which can affect pro- and anti-oxidative systems locally or systemically. Therefore, this study aimed to investigate the potential influence of direct capping of inflamed rat dental pulp with calcium hydroxide (CH) and mineral trioxide aggregate (MTA) on parameters of systemic oxidative status. Dental pulps of the first maxillary molars of Albino rats (n=32) were exposed and capped with either CH (n=8), MTA (n=8) or were left untreated (n=8). Animals with healthy pulp were used as a healthy control (n=8). After four weeks, animals were euthanized and blood samples were collected for biochemical analysis of parameters of systemic oxidative stress by spectrophotometric method. Untreated control had the significantly higher (p &lt;0.05) values of pro-oxidative parameters and lower (p &lt;0.05) values of anti-oxidative parameters (superoxide dismutase and reduced glutathione) compared to healthy control. CH and MTA groups showed reduced values of pro-oxidative parameters compared to untreated control and values of anti-oxidative parameters comparable to healthy control. Pulp exposure led to disbalance in systemic oxidative parameters while direct pulp capping with calcium hydroxide and mineral trioxide aggregate restored the levels of systemic oxidative parameters to that of animals with healthy dental pulp. These results indicate the importance of direct pulp capping and the potential influence of untreated inflamed pulp on systemic health.

Expression of Toll-like receptor 2, Dectin-1, and Osteopontin in murine model of pulpitis.

This in vivo animal study aimed to develop a murine model of pulpitis induced by pulp exposure with or without application of zymosan in Naval Medical Research Institute (NMRI) mice and observe expressions of Toll-like receptor (TLR)-2, TLR-4, Dectin-1, Osteopontin (OPN), tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, and IL-1ß. A total of 168 NMRI mice were divided into two groups, i.e., group A (n = 84) (pulpitis induced by pulp exposure only) and group B (n = 84) (pulpitis induced by pulp exposure and zymosan application). Right maxillary molar pulps were exposed with ¼ round bur, and animals were sacrificed at 0, 6, 9, 12, 24, 48, and 72h. The exposed teeth were obtained for real-time polymerase chain reaction (qRT-PCR) analysis and histological and immunohistochemistry (IHC) analysis. Histological evaluation revealed a time-dependent steady increase in inflammation. Similar time-dependent increase in the expression of inflammatory cytokines was noted. Group A exhibited an increase in TLR-4, Dectin-1, and OPN at 6h, while TLR-2 was expressed at 24h. Group B expressed TLR-2, Dectin-1, and OPN at 9, 48, and 72h, respectively (p ≤ 0.05). Expression of OPN and TNF-α exhibited a similar pattern in both groups. IHC also detected expression of TLR-2, Dectin-1, TLR4, and CD68 in some cells at 6 and 9h. NMRI mice provided for a stable pulp inflammation model. Zymosan may be used to develop pulp inflammation model and study inflammatory response towards fungal antigens. Dental pulp expressed Dectin-1 receptor. OPN and TNF-α exhibited a similar expression pattern. Innate immunity of dental pulp is capable of detecting fungal pathogens.

Pre-eruptive intracoronal resorption in “high-risk” impacted third molars: A report of four cases

Pre-eruptive intracoronal resorption (PEIR) is usually an incidental finding as a radiolucent lesion within the coronal dentin of unerupted teeth. Through the four cases reported here, authors would demonstrate deeply impacted “high-risk” third molars with PEIR defects, showing an increased risk of inferior alveolar nerve (IAN) injury. However, follow-up or coronectomy may eliminate or reduce the risk of neurosensory disturbances, in case of PEIR lesions this can be contradictory due to the unpredictable reactions of the third molar's pulp. Cases show the important role of preoperative imaging in the diagnostics and management of deeply impacted PEIR third molars and highlight the need for investigations regarding coronectomy in such cases.

Pulpal expression of erythropoietin and erythropoietin receptor after direct pulp capping in rat

This study aimed to evaluate the effect of direct pulp capping on the expression of erythropoietin (Epo) and Epo-receptor (Epor) genes in relation to the expression of inflammatory and osteogenic genes in rat pulp. Dental pulps of the first maxillary molars of Wistar Albino rats were exposed and capped with either calcium hydroxide or mineral trioxide aggregate, or were left untreated. After 4 wk, animals were euthanized, and maxillae were prepared for histological and real-time polymerase chain reaction analysis. Histological scores of pulp inflammation and mineralization, and relative expressions of Epo, Epor, inflammatory cytokines, and pulp osteogenic genes were evaluated. The capped pulps showed higher expressions of Epo, while the untreated pulps had the highest expression of Epor. Both calcium hydroxide and mineral trioxide aggregate downregulated the expression of tumor necrosis factor alpha compared to untreated controls, and upregulated transforming growth factor beta compared to healthy controls. Alkaline phosphatase expression was significantly higher in experimental groups. Relative expression of Epo negatively correlated with pulp inflammation, and positively correlated with pulp mineralization. Pulp exposure promoted expression of Epor and pro-inflammatory cytokines, while pulp capping promoted expression of Epo, alkaline phosphatase, and downregulated Epor and pro-inflammatory cytokines.

VEGFA promotes odonto/osteoblastic differentiation in dental pulp stem cells via ERK/p38 signaling

Background/purpose: Vascular endothelial growth factor A (VEGFA) is a potent angiogenic factor and an essential growth factor for vascular endothelial cells, but its effects on dental pulp stem cells, such as stem cells from human exfoliated deciduous teeth (SHEDs), have not been fully evaluated. The aim of this study was to explore the effects and underlying mechanisms of VEGFA on odonto/osteoblastic differentiation in SHEDs in vitro. This study also aimed to examine the mineralized tissue-forming and pro-angiogenic potentials of VEGFA in rat dental pulp in vivo. Materials and methodsProliferation, migration, odonto/osteoblastic gene expression, and mineralized nodule formation were evaluated in SHEDs after stimulation with recombinant human VEGFA (rhVEGFA). Expression patterns of extracellular signal-regulated kinase (ERK) and p38/mitogen-activated protein kinase (MAPK) were analysed by western blotting. Rat molar pulp was histologically and immunohistochemically examined after 10 days of rhVEGFA-soaked agarose bead exposure. ResultsrhVEGFA stimulation promoted migration, mRNA expression of odonto/osteoblastic markers RUNX family transcription factor 2 (RUNX2) and alkaline phosphatase (ALP), and mineralized nodule formation in SHEDs; these effects were reduced by ERK and p38/MAPK inhibitors. RhVEGFA-treated rat molar pulp tissues exhibited a reparative dentin-like mineralized tissue with surrounding nestin-positive cells and densely distributed CD146+ vascular vessels. ConclusionrhVEGFA can promote migration, odonto/osteoblastic differentiation, and mineralized nodule formation via ERK/p38 signaling in SHEDs in vitro; it promotes mineralized tissue formation and neovascularization in pulp tissue in vivo.

Morphological, histological, and chemical analysis of first permanent molars with molar incisor malformation.

Molar incisor malformation (MIM) is a dental anomaly rendering first permanent molar pulps inflamed/necrotic at a young age. It often affects permanent incisors, primary second molars and less frequently other teeth. The purpose of this study was to investigate the anatomy and histology of MIM in seeking insight into its pathogenesis. Five MIM first permanent molars were examined with micro-computed tomography (micro-CT) for 3D morphology, with scanning electron microscopy for microanatomy, with energy-dispersive X-ray spectrometer (EDS) for chemical composition and for histology with optical microscopy. Composition differences were statistically determined using one-way ANOVA. Micro-CT confirmed dentin abnormalities in the middle and cervical third of the crown in the form of the radiodense 'cervical mineralized diaphragm' (CMD). This was peripherally intertwined with enamel fjords and projections severely disrupting the integrity of pulp chamber and its continuity with root canals. EDS showed increased Ca in CMD compared to dentin. The histological examination revealed anomalous osteodentin-like hard tissue with denticles in the CMD. An interconnection of anomalous cervical enamel with crown CMD dentin preceded to the severe pulp chamber and root dysplasias in MIM molar teeth.