Reparative Dentin Formation Research Articles

CT-Assisted Management with Biodentine Obturation and Aesthetic Rehabilitation of a Geminated Maxillary Central Incisor with Mid-Root Fracture: A Rare Case Report

Gemination, a rare aberration in tooth development, results from the incomplete division of one tooth germ into two. In this case report, a true geminated permanent maxillary central incisor tooth with a horizontal mid-root fracture is successfully treated by non-surgical endodontic treatment. To elucidate the intricate root canal anatomy of this rare geminated incisor, we employed computed tomography imaging technology, enhancing our understanding of this complex case. Utilizing biodentine for obturation proved pivotal, as its capacity to accelerate reparative dentin formation facilitated prompt healing, particularly beneficial in fracture cases. This was followed by aesthetic rehabilitation to achieve a pleasing mesio-distal dimension for both the central incisors using a zirconia-reinforced porcelain crowns. Keywords: Computed Tomography (CT), Gemination, Horizontal root fracture, Biodentine Obturation

Injectable Tannin-Containing Hydroxypropyl Chitin Hydrogel as Novel Bioactive Pulp Capping Material Accelerates Repair of Inflamed Dental Pulp.

Conventional pulp capping materials have limited anti-inflammatory capacity. It is necessary to develop more effective pulp capping material for the treatment of inflamed pulps. Tannic acid (TA) is a natural, water-soluble polyphenol with antimicrobial and anti-inflammatory properties. This study aimed to investigate the effects of a tannin-containing hydroxypropyl chitin hydrogel (HPCH/TA hydrogel) as an innovative pulp capping material. The physicochemical properties of the composite hydrogels were characterized. The effects of HPCH/TA hydrogel as a pulp capping material were evaluated in vitro and in vivo. The underlying mechanism of the anti-inflammatory effects of HPCH/TA hydrogel was explored. The HPCH/TA hydrogel demonstrated favorable temperature sensitivity, injectability, and antibacterial properties. In vitro, the HPCH/TA hydrogel effectively promoted the proliferation of human dental pulp cells and inhibited interleukin-1β, interleukin-6, and tumor necrosis factor-α expression, possibly by suppressing the nuclear factor kappa-B pathway. In vivo, on the fourth day after capping, the HPCH/TA hydrogel group showed lower inflammatory scores compared to the control and iRoot BP Plus (commercial pulp capping material) group. By the sixth week, complete reparative dentin formation was observed in the HPCH/TA hydrogel group, with no difference in thickness compared to the iRoot BP Plus group. Collectively, the HPCH/TA hydrogel holds promise as a bioactive pulp capping material for promoting the repair of inflamed pulp in vital pulp therapy.

Radiographic Evaluation of Reparative Dentin Formation after Direct Pulp Capping Using Rosuvastatin vs Mineral Trioxide Aggregate on Young Mature Permanent Molar—90 Days of Follow-up: A Split-mouth Study

Radiographic Evaluation of Reparative Dentin Formation after Direct Pulp Capping Using Rosuvastatin vs Mineral Trioxide Aggregate on Young Mature Permanent Molar—90 Days of Follow-up: A Split-mouth Study

Ginsenoside RB1 Influences Macrophage–DPSC Interactions in Inflammatory Conditions

Unresolved inflammation and tissue destruction are supposed to underlie the failure of dental pulp repair. As crucial regulators of the injury response, dental pulp stem cells (DPSCs) play a key role in pulp tissue repair and regeneration. M2 macrophages have been demonstrated to induce osteogenic/odontogenic differentiation of DPSCs. Ginsenoside Rb1 (GRb1) is the major component of ginseng and manifested an anti-inflammatory role by promoting M1 macrophage polarised into M2 macrophage in inflammatory disease. However, whether GRb1 facilitates odontogenic differentiation of DPSCs via promoting M2 macrophage polarisation under inflammatory conditions has yet to be established. Human monocyte leukemic cells (THP-1) differentiated macrophages were induced into M1 subsets and then treated with GRb1. After that, the conditioned medium was added to DPSCs. The cell co-cultured system was then subjected to odontogenic differentiation in osteogenic media. Effects of GRb1 on human dental pulp stem cells' (hDPSCs') osteogenic/odontogenic differentiation under inflammatory conditions were assessed by alkaline phosphatase (ALP) staining, Alizarin Red S (ARS) staining, and quantitative polymerase chain reaction testing. Results demonstrated that GRb1 could facilitate the polarisation of macrophages from the M1 subtype to the M2 subtype. Conditioned medium from GRb1 + M1 macrophages, in comparison with M1 macrophages, may markedly increase the gene expression of ALP, DSPP, and DMP1. Moreover, ALP and ARS staining uncovered that the osteogenic/odontogenic differentiation ability of hDPSCs was strengthened in the M1 + GRb1 co-culture group. GRb1 plays a crucial role in the inflammatory response and reparative dentine formation after dental pulp injury. Findings show that GRb1 modulates the interaction between macrophages and DPSCs during inflammation. The current study discusses modifications of deep caries therapy.

Effect of four direct pulp capping agents on human dental pulp tissue.

Direct pulp capping (DPC) is a vital pulp therapy, wherein accidental or carious pulp exposures can be capped with various materials to induce reparative dentine formation. One of the major factors that determine the success of direct pulp capping procedures is the material used. Therefore, it is of interest to evaluate and compare the efficacy of a new material, Tristrontium aluminate in comparison with the widely used materials such as ProRoot MTA, Biodentine & TheraCal LC. Hence, 40 premolars scheduled for extraction for orthodontic treatment, were equally divided into 4 groups and iatrogenic DPC was done using one of the study materials. The premolars were then extracted after 90 days & assessed for the formation of Dentine Bridge and pulpal response elicited by the materials using CBCT and histopathological analysis. All the materials tested in the study were successful in inducing dentine bridge formation & maintaining pulp vitality. Thus, the novelty of Tristrontium aluminate for potential applications in future is eminent.

Differences of compressive strength between calcium carbonate from blood clam shells and calcium hydroxide as a candidate for pulp capping material

Background: Pulp capping is one of the treatments for reversible pulpitis and aims to maintain pulp vitality. This treatment requires a material that can protect the pulp with good biocompatibility. The physical and mechanical properties, bio interactivity and bioactivity of pulp capping materials are very important for the formation of reparative dentin. Calcium hydroxide (Ca(OH)2) as the gold standard material in pulp capping treatment also has some disadvantages. Another alternative for pulp capping material is blood clam shell because it contains 98% calcium carbonate (CaCO3), which is a compound with a bone-like structure and can induce pulp cell differentiation. Objective: To investigate and explain the difference in compressive strength between CaCO3 from blood clam shells and Ca(OH)2 as a candidate pulp capping material. Methods: This research is a laboratory experimental study with post test only control group design method. Ca(OH)2 and CaCO3 samples were formed with a mixture of powder and aquadest with 4x6 mm sample size. The samples were dried at room temperature and the compressive strength was measured using a universal testing machine (UTM). Result: There is a significant difference in compressive strength between Ca(OH)2 and CaCO3 blood clam shells in the Mann-Whitney test results (p<0.05). Conclusion: The results of the compressive strength test between the mixture of Ca(OH)2 with aquadest in a ratio of 1:1 are greater than the mixture of CaCO3 blood clam shells with aquadest in a ratio of 3:1 so that pure CaCO3 blood clam shells with distilled water without other additives cannot be used as a candidate for capping pulp material.

Novel L-(CaP-ZnP)/SA Nanocomposite Hydrogel with Dual Anti-Inflammatory and Mineralization Effects for Efficient Vital Pulp Therapy.

Vital pulp therapy (VPT) is considered a conservative treatment for preserving pulp viability in caries and trauma-induced pulpitis. However, Mineral trioxide aggregate (MTA) as the most frequently used repair material, exhibits limited efficacy under inflammatory conditions. This study introduces an innovative nanocomposite hydrogel, tailored to simultaneously target anti-inflammation and dentin mineralization, aiming to efficiently preserve vital pulp tissue. The L-(CaP-ZnP)/SA nanocomposite hydrogel was designed by combining L-Arginine modified calcium phosphate/zinc phosphate nanoparticles (L-(CaP-ZnP) NPs) with sodium alginate (SA), and was characterized with TEM, SEM, FTIR, EDX, ICP-AES, and Zeta potential. In vitro, we evaluated the cytotoxicity and anti-inflammatory properties. Human dental pulp stem cells (hDPSCs) were cultured with lipopolysaccharide (LPS) to induce an inflammatory response, and the cell odontogenic differentiation was measured and possible signaling pathways were explored by alkaline phosphatase (ALP)/alizarin red S (ARS) staining, qRT-PCR, immunofluorescence staining, and Western blotting, respectively. In vivo, a pulpitis model was utilized to explore the potential of the L-(CaP-ZnP)/SA nanocomposite hydrogel in controlling pulp inflammation and enhancing dentin mineralization by Hematoxylin and eosin (HE) staining and immunohistochemistry staining. In vitro experiments revealed that the nanocomposite hydrogel was synthesized successfully and presented desirable biocompatibility. Under inflammatory conditions, compared to MTA, the L-(CaP-ZnP)/SA nanocomposite hydrogel demonstrated superior anti-inflammatory and pro-odontogenesis effects. Furthermore, the nanocomposite hydrogel significantly augmented p38 phosphorylation, implicating the involvement of the p38 signaling pathway in pulp repair. Significantly, in a rat pulpitis model, the L-(CaP-ZnP)/SA nanocomposite hydrogel downregulated inflammatory markers while upregulating mineralization-related markers, thereby stimulating the formation of robust reparative dentin. The L-(CaP-ZnP)/SA nanocomposite hydrogel with good biocompatibility efficiently promoted inflammation resolution and enhanced dentin mineralization by activating p38 signal pathway, as a pulp-capping material, offering a promising and advanced solution for treatment of pulpitis.

Resolvin D2-induced reparative dentin and pulp stem cells after pulpotomy in a rat model

IntroductionVital pulp therapy (VPT) is performed to preserve dental pulp. However, the biocompatibility of the existing materials is of concern. Therefore, novel materials that can induce pulp healing without adverse effects need to be developed. Resolvin D2 (RvD2), one of specialized pro-resolving mediators, can resolve inflammation and promote the healing of periapical lesions. Therefore, RvD2 may be suitable for use in VPT. In the present study, we evaluated the efficacy of RvD2 against VPT using in vivo and in vitro models. MethodsFirst molars of eight-week-old male Sprague–Dawley rats were used for pulpotomy. They were then divided into three treatment groups: RvD2, phosphate-buffered saline, and calcium hydroxide groups. Treatment results were assessed using radiological, histological, and immunohistochemical (GPR18, TNF-α, Ki67, VEGF, TGF-β, CD44, CD90, and TRPA1) analyses. Dental pulp-derived cells were treated with RvD2 in vitro and analyzed using cell-proliferation and cell-migration assays, real-time PCR (Gpr18, Tnf-α, Il-1β, Tgf-β, Vegf, Nanog, and Trpa1), ELISA (VEGF and TGF-β), immunocytochemistry (TRPA1), and flow cytometry (dental pulp stem cells: DPSCs). ResultsThe formation of calcified tissue in the pulp was observed in the RvD2 and calcium hydroxide groups. RvD2 inhibited inflammation in dental pulp cells. RvD2 promoted cell proliferation and migration and the expression of TGF-β and VEGF in vitro and in vivo. RvD2 increased the number of DPSCs. In addition, RvD2 suppressed TRPA1 expression as a pain receptor. ConclusionRvD2 induced the formation of reparative dentin, anti-inflammatory effects, and decreased pain, along with the proliferation of DPSCs via the expression of VEGF and TGF-β, on the pulp surface in pulpotomy models.

Silicon impacts collagen remodelling and mineralization by human dental pulp stem cells in 3D pulp-like matrices

ObjectivesSilicon-releasing biomaterials are widely used in the field of dentistry. However, unlike bone, very little is known about the role of silicon on dental tissue formation and repair. This study investigates the influence of silicic acid on the survival, differentiation and mineralizing ability of human dental pulp stem cells (hDPSCs) in 3D pulp-like environments MethodsDense type I collagen hydrogels seeded with hDPSCs were cultured over 4 weeks in the presence of silicic acid at physiological (10 μM) and supraphysiological (100 μM) concentrations. Cell viability and proliferation were studied by Alamar Blue and live/dead staining. The collagen network was investigated using second harmonic generation imaging. Mineral deposition was monitored by histology and scanning electron microscopy. Gene expression of mineralization- and matrix remodeling-associated proteins was studied by qPCR. ResultsPresence of silicic acid did not show any significant influence on cell survival, metabolic activity and gene expression of key mineralization-related proteins (ALP, OCN, BSP). However, it induced enhanced cell clustering and delayed expression of matrix remodeling-associated proteins (MMP13, Col I). OPN expression and mineral deposition were inhibited at 100 μM. It could be inferred that silicic acid has no direct cellular effect but rather interacts with the collagen network, leading to a modification of the cell-matrix interface. SignificanceOur results offer advanced insights on the possible role of silicic acid, as released by pulp capping calcium silicates biomaterials, in reparative dentine formation. More globally, these results interrogate the possible role of Si in pulp pathophysiology.

Electrical Stimulations Generated by P(VDF-TrFE) Films Enhance Adhesion Forces and Odontogenic Differentiation of Dental Pulp Stem Cells (DPSCs).

Biophysical and biochemical cues of biomaterials can regulate cell behaviors. Dental pulp stem cells (DPSCs) in pulp tissues can differentiate to odontoblast-like cells and secrete reparative dentin to form a barrier to protect the underlying pulp tissues and enable complete pulp healing. Promotion of the odontogenic differentiation of DPSCs is essential for dentin regeneration. The effects of the surface potentials of biomaterials on the adhesion and odontogenic differentiation of DPSCs remain unclear. Here, poly(vinylidene fluoride-trifluoro ethylene) (P(VDF-TrFE)) films with different surface potentials were prepared by the spin-coating technique and the contact poling method. The cytoskeletal organization of DPSCs grown on P(VDF-TrFE) films was studied by immunofluorescence staining. Using atomic force microscopy (AFM), the lateral detachment forces of DPSCs from P(VDF-TrFE) films were quantified. The effects of electrical stimulation generated from P(VDF-TrFE) films on odontogenic differentiation of DPSCs were evaluated in vitro and in vivo. The unpolarized, positively polarized, and negatively polarized films had surface potentials of -52.9, +902.4, and -502.2 mV, respectively. DPSCs on both negatively and positively polarized P(VDF-TrFE) films had larger cell areas and length-to-width ratios than those on the unpolarized films (P < 0.05). During the detachment of DPSCs from P(VDF-TrFE) films, the average magnitudes of the maximum detachment forces were 29.4, 72.1, and 53.9 nN for unpolarized, positively polarized, and negatively polarized groups, respectively (P < 0.05). The polarized films enhanced the mineralization activities and increased the expression levels of the odontogenic-related proteins of DPSCs compared to the unpolarized films (P < 0.05). The extracellular signal-regulated kinase (ERK) signaling pathway was involved in the odontogenic differentiation of DPSCs as induced by surface charge. In vivo, the polarized P(VDF-TrFE) films enhanced adhesion of DPSCs and promoted the odontogenic differentiation of DPSCs by electrical stimulation, demonstrating a potential application of electroactive biomaterials for reparative dentin formation in direct pulp capping.

Effect of Heparan Sulfate on Vasculogenesis and Dentinogenesis of Dental Pulp Stem Cells

IntroductionHeparan sulfate (HS) is a major component of dental pulp tissue. We previously reported that inhibiting HS biosynthesis impedes endothelial differentiation of dental pulp stem cells (DPSCs). However, the underlying mechanisms by which exogenous HS induces DPSC differentiation and pulp tissue regeneration remain unknown. This study explores the impact of exogenous HS on vasculogenesis and dentinogenesis of DPSCs both in vitro and in vivo. MethodsHuman-derived DPSCs were cultured in endothelial and odontogenic differentiation media and treated with HS. Endothelial differentiation of DPSCs was investigated by real-time polymerase chain reaction and capillary sprouting assay. Odontogenic differentiation was assessed through real-time polymerase chain reaction and detection of mineralized dentin-like deposition. Additionally, the influence of HS on pulp tissue was assessed with a direct pulp capping model, in which HS was delivered to exposed pulp tissue in rats. Gelatin sponges were loaded with either phosphate-buffered saline or 101–102 μg/mL HS and placed onto the pulp tissue. Following a 28-day period, tissues were investigated by histological analysis and micro–computed tomography imaging. ResultsHS treatment markedly increased expression levels of key endothelial and odontogenic genes, enhanced the formation of capillary-like structures, and promoted the deposition of mineralized matrices. Treatment of exposed pulp tissue with HS in the in vivo pulp capping study induced formation of capillaries and reparative dentin. ConclusionsExogenous HS effectively promoted vasculogenesis and dentinogenesis of DPSCs in vitro and induced reparative dentin formation in vivo, highlighting its therapeutic potential for pulp capping treatment.

Hard tissue formation in pulpotomized primary teeth in dogs with nanomaterials MCM-48 and MCM-48/hydroxyapatite: an in vivo animal study

BackgroundThis animal study sought to evaluate two novel nanomaterials for pulpotomy of primary teeth and assess the short-term pulpal response and hard tissue formation in dogs. The results were compared with mineral trioxide aggregate (MTA).MethodsThis in vivo animal study on dogs evaluated 48 primary premolar teeth of 4 mongrel female dogs the age of 6–8 weeks, randomly divided into four groups (n = 12). The teeth underwent complete pulpotomy under general anesthesia. The pulp tissue was capped with MCM-48, MCM-48/Hydroxyapatite (HA), MTA (positive control), and gutta-percha (negative control), and the teeth were restored with intermediate restorative material (IRM) paste and amalgam. After 4–6 weeks, the teeth were extracted and histologically analyzed to assess the pulpal response to the pulpotomy agent.ResultsThe data were analyzed using the Kruskal‒Wallis, Fisher’s exact, Spearman’s, and Mann‒Whitney tests. The four groups were not significantly different regarding the severity of inflammation (P = 0.53), extent of inflammation (P = 0.72), necrosis (P = 0.361), severity of edema (P = 0.52), extent of edema (P = 0.06), or connective tissue formation (P = 0.064). A significant correlation was noted between the severity and extent of inflammation (r = 0.954, P < 0.001). The four groups were significantly different regarding the frequency of bone formation (P = 0.012), extent of connective tissue formation (P = 0.047), severity of congestion (P = 0.02), and extent of congestion (P = 0.01). No bone formation was noted in the gutta-percha group. The type of newly formed bone was not significantly different among the three experimental groups (P = 0.320).ConclusionMCM-48 and MCM-48/HA are bioactive nanomaterials that may serve as alternatives for pulpotomy of primary teeth due to their ability to induce hard tissue formation. The MCM-48 and MCM-48/HA mesoporous silica nanomaterials have the potential to induce osteogenesis and tertiary (reparative) dentin formation.

Induction of Reparative Dentin Following Pulpotomy with BiodentineTM at Four Week Follow up visit: A Case Report

Pulpotomy materials have been used in dentistry with the expectation of induction of reparative dentin for maintain of pulp vitality in mature permanent premolar tooth. However, few histopathological studies have been performed in vivo with healthy tooth. This study was perfumed to examine whether pulpotomy with calcium-silicate based BiodentineTM could induce reparative dentin formation without eliciting adverse side effects of premolar teeth, in vivo. In this study, pulpotomy was performed on upper left first premolar tooth (which is needed to extract for aesthetic reason) with BiodentineTM and then the quality and quantity of reparative dentin was assessing by histological analysis at 28 days. It was found that the thickness of reparative dentin formation was 1.4 ± 0.4 µm that completely covers the exposed pulp tissue. It can be concluded that BiodentineTM is capable to induce pulpal wound healing and reparative formation in the exposed teeth without affecting the normal function of the remaining pulp.

Exploring the staining potential of 1 GSK-3 inhibitors in bovine teeth: 2 a one-year laboratory investigation.

GSK-3 inhibitors, such as Tideglusib (TG) and CHIR-99021 (CHIR), show promise in stimulating reparative dentin formation. The aim of this study was to assess the discoloration potential of TG and CHIR in an established in vitro model. Enamel-dentin specimens made from bovine incisors were randomly allocated to five groups (n=15 each): group bovine blood (BB), group dimethyl sulfoxide (DMSO), group TG, group CHIR, and group mineral trioxide aggregate (MTA). Each specimen had a central cavity in which the respective material was applied and sealed with resin-based luting material. Color determination was conducted using a dental spectrophotometer at t0 (before filling), t1 (immediately after filling), t2 (after one week), t3 (after one month), t4 (after three months), t5 (after six months), and t6 (after one year). Statistical analysis involved descriptive statistics, Kruskal-Wallis tests, and analysis of variance (α=0.05). Group BB and group CHIR exhibited the most significant decrease in lightness (ΔL*) after one year (ΔL*-4.7 and ΔL* -5.7, respectively), whereas groups DMSO, TG, and MTA showed minimal changes (DMSO ΔL*: -0.3; TG ΔL*: 1.4; MTA ΔL*: -0.5). Group BB and CHIR exhibited the highest ΔE values (6.4Å}0.6 and 6.5Å}0.8, respectively). Unlike CHIR, TG did not result in discoloration exceeding the threshold of visual perception, defined by a ΔE value of 5.5, during the one-year observation period. This laboratory study therefore suggests that TG could be utilized for indirect or direct pulp capping without major discoloration concerns. However, additional research is required to corroborate these findings.

Vascular Endothelial Growth Factor Expression in Pulp Regeneration Treated By Hyaluronic Acid Gel in Rabbits

Among the most common dental problems, dental caries and trauma lead to the development of cavities and even tooth loss. Therefore, new regeneration techniques that are effective and toxic-free are needed. The use of scaffolds has created possibilities for the regeneration of tooth structure. Hydrogels made of hyaluronic acid have drawn many attention in regenerative medicine. Consequently, the objectives of the study were to estimate the impact of hyaluronic acid on pulp regeneration using histological evaluation and immunohistochemical localization of vascular endothelial growth factor (VEGF). The entire sample consisted of 20 teeth (right and left upper central incisors) from ten rabbits, Their ages were between 10 and 12 months. They were used for pulp exposure and coronal pulp tissue removal. After pulp exposure, hyaluronic acid hydrogels were injected into the pulp chambers of the right upper central incisors in the experimental group to promote pulp regeneration. The pulp chambers of the left upper central incisors considered as the control group, and they were temporarily filled in without the injection of hyaluronic acid. The histological and immunohistochemical evaluations were done in two time periods: the first and second week after pulp exposure. The histological results showed the formation of reparative dentin in the experimental group with a high mean value (56.3) regarding predentin thickness, especially in the second-week duration, and a significant difference as compared with the control group. The immunohistochemical results disclosed that the experimental group showed strong positive expression for vascular endothelial growth factor in different pulpal cells with the highest mean value of the number of positively expressed cells (34.3) in the second- week duration, with a significant difference as compared with the control group. Hyaluronic acid hydrogel had a supporting function in pulp regeneration, according to the findings of the current study. This was demonstrated by an increase in the expression of VEGF throughout the cells in pulp tissue.

Injectable CNPs/DMP1-loaded self-assembly hydrogel regulating inflammation of dental pulp stem cells for dentin regeneration

Vital pulp preservation, which is a clinical challenge of aseptic or iatrogenic accidental exposure of the pulp, in cases direct pulp capping is the main technology. Human dental pulp stem cells (hDPSCs) play a critical role in pulp tissue repair, but their differentiative ability could be inhibited by the potential infection and inflammatory response of the exposed pulp. Therefore, inflammatory regulation and differentiated promotion of hDPSCs are both essential for preserving living pulp teeth. In this study, we constructed a functional dental pulp-capping hydrogel by loading cerium oxide nanoparticles (CNPs) and dentin matrix protein-1 (DMP1) into an injectable Fmoc–triphenylalanine hydrogel (Fmoc-phe3 hydrogel) as CNPs/DMP1/Hydrogel for in situ drugs delivery. With a view to long-term storage and release of CNPs (anti-inflammatory and antioxidant) to regulate the local inflammatory environment and DMP1 to promote the regeneration of dentin. Results of CCK-8, LDH release, hemolysis, and Live/Dead assessment of cells demonstrated the good biocompatibility of CNPs/DMP1/Hydrogel. The levels of alkaline phosphatase activity, quantification of the mineralized nodules, expressions of osteogenic genes and proteins demonstrated CNPs/DMP1/Hydrogel could protect the activity of hDPSCs’ osteogenic/dentinogenic differentiation by reducing the inflammation response via releasing CNPs. The therapy effects were further confirmed in rat models, CNPs/DMP1/Hydrogel reduced the necrosis rate of damaged pulp and promoted injured pulp repair and reparative dentin formation with preserved vital pulps. In summary, the CNPs/DMP1/Hydrogel composite is an up-and-coming pulp-capping material candidate to induce reparative dentin formation, as well as provide a theoretical and experimental basis for developing pulp-capping materials.

Effect of pulp capping materials on odontogenic differentiation of human dental pulp stem cells: An in vitro study.

Migration and differentiation of human dental pulp stem cells (hDPSCs) is a vital and key factor in the success of reparative dentin formation for maintenance of pulp vitality. Pulp capping materials are used to stimulate DPSCs to induce new dentin formation. Thus, the aim of the present study was to compare the response of DPSCs to four commercially available pulp capping materials: a bioactive bioceramic (Material 1), a nonresinous ready-to-use bioceramic cement (Material 2), a bioactive composite (Material 3),and a biocompatible, dual-cured, resin-modified calcium silicate (Material 4). hDPSCs were isolated and cultured from freshly extracted teeth and were then characterized by flow cytometry and multilineage differentiation. Discs prepared from pulp capping materials were tested with hDPSCs and MTT(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, cell migration assay and odontogenic differentiation assay was performed. Expression of osteogenic markers (osteopontin, RUNX family transcription factor 2, osteocalcin) and the odontogenic marker (dentin sialophosphoprotein) was detected using reverse transcription-polymerase chain reaction. Materials 1, 2, and 3 generated more cell viability than Material 4. Furthermore, Material 4 showed the least wound exposure percentage, while Material 3 showed the highest percentage. Enhanced mineralization was found in hDSCPs cultured with Material 3,followed by Material 1, and then Material 2, while Material 4 revealed the least calcified mineralization. The results of this study were inconclusive regards contemporary bioceramic materials designed for vital pulp therapy as they have different effects on hDPSC. Further testing for cytotoxicity using live-dead staining, animal experiments, clinical trials, and independent analyses of these biomaterials is necessary for clinicians to make an informed decision for their use.

The histone deacetylase inhibitor MS-275 enhances the matrix mineralization of dental pulp stem cells by inducing fibronectin expression

Background/purposeThe acetylation of histone H3 proteins keeps local chromatin regions open and accessible, thereby facilitating transcriptional events. We recently reported integrative epigenomic and transcriptome analyses of differentiating dental pulp stem cells (DPSCs). A significant increase in the number of super-enhancers, which are local genomic locations marked by condensed open chromatin peaks that facilitate transcriptional events, in differentiating DPSCs were observed. However, it is still unclear whether histone deacetylase (HDACs) inhibitors (HDACis) have beneficial effects on the odontogenic differentiation of DPSCs and on the matrix mineralization-inducing ability of DPSCs. Materials and methodsDPSCs were cultured in an odontogenic induction medium for a prolonged period in the presence of HDACis, MS-275 and Trichostatin A (TSA). ATAC-seq and RNA-seq samples were collected from differentiating DPSCs to explore the epigenomic and transcriptomic alterations induced by HDACis and identify key target proteins that mediate HDACis-induced phenotypic changes. ResultsMS-275 and TSA did not change whole-genome open chromatin accessibility or increase odontogenic differentiation, as assessed by alkaline phosphate activity. However, the matrix mineralization-inducing ability assessed by calcified nodule formation was significantly increased by MS-275 but not by TSA. FN1, which encodes fibronectin, was identified as upregulated by MS-275. The knockdown of fibronectin evidently suppressed MS-275-induced calcified nodule formation. ConclusionMS-275 induced calcified nodule formation by the mechanistic upregulation of FN1, independent of epigenomic alterations. Hence, the application of MS-275 as direct capping materials has therapeutic potential for promoting reparative dentin formation by constructing a fibronectin-organizing physiological extracellular matrix environment that is adequate for matrix mineralization.

Evaluation of Indirect Pulp Capping Using MTA, Light-cured Calcium Silicate, and Propolis in Primary Teeth: A Clinical and Radiographic Study Using VistaScan.

Clinical and radiographic evaluation of mineral trioxide aggregate (MTA), TheraCal LC, and propolis when used as an indirect pulp capping agent in primary teeth over a period of 6 months. A total of 42 primary molar teeth from children aged 4-10 years were chosen for the study. The teeth were divided equally into three groups (group I: MTA, group II: light cured calcium silicate, and group III: propolis). The teeth were followed up clinically and radiographically at 3 and 6 months. The teeth that showed successful treatment outcomes clinically and radiographically were evaluated for the amount of dentin bridge formed at the end of 3 and 6 months, which was measured using CorelDRAW software. The data obtained was analyzed statistically using Statistical Package for the Social Sciences (SPSS) version 21. The mean change in dentin thickness from baseline to 3 months in group II was found to be the highest, followed by groups I and III. The mean change in dentin thickness from 3 months to 6 months was highest in group I, followed by groups III and II. The mean change in dentin thickness from baseline to 6 months in group II was found to be significantly higher than that of group I, followed by group III. Clinically and radiographically, all three materials showed favorable outcomes when used as an indirect pulp capping material with significant reparative dentin formation. The highest amount of dentin deposition was recorded with light-cured calcium silicate, followed by MTA and propolis, respectively. Saikia D, Yadav G, Saha S, et al. Evaluation of Indirect Pulp Capping Using MTA, Light-cured Calcium Silicate, and Propolis in Primary Teeth: A Clinical and Radiographic Study Using VistaScan. Int J Clin Pediatr Dent 2023;16(5):686-691.

Sensory nerves, but not sympathetic nerves, promote reparative dentine formation after dentine injury via CGRP-mediated angiogenesis: An in vivo study.

Dental pulp is richly innervated by nerve fibres, which are mainly involved in the sensation of pain. Aside from pain sensation, little is known regarding the role of dental innervation in reparative dentine formation. We herein generated a mouse model of experimental dentine injury to examine nerve sprouting within the odontoblast and subodontoblastic layers and investigated the potential effects of this innervation in reparative dentinogenesis. Mouse tooth cavity model (bur preparation + etching) was established, and then nerve sprouting, angiogenesis and reparative dentinogenesis were determined by histological and immunofluorescent staining at 1, 3, 7, 14 and 28 days postoperatively. We also established the mouse-denervated molar models to determine the role of sensory and sympathetic nerves in reparative dentinogenesis, respectively. Finally, we applied calcitonin gene-related peptide (CGRP) receptor antagonist to analyse the changes in angiogenesis and reparative dentinogenesis. Sequential histological results from dentine-exposed teeth revealed a significant increase in innervation directly beneath the injured area on the first day after dentine exposure, followed by vascularisation and reparative dentine production at 3 and 7 days, respectively. Intriguingly, abundant type H vessels (CD31+ Endomucin+ ) were present in the innervated area, and their formation precedes the onset of reparative dentine formation. Additionally, we found that sensory denervation led to blunted angiogenesis and impaired dentinogenesis, while sympathetic denervation did not affect dentinogenesis. Moreover, a marked increase in the density of CGRP+ nerve fibres was seen on day 3, which was reduced but remained elevated over the baseline level on day 14, whereas the density of substance P-positive nerve fibres did not change significantly. CGRP receptor antagonist-treated mice showed similar results as those with sensory denervation, including impairments in type H angiogenesis, which confirms the importance of CGRP in the formation of type H vessels. Dental pulp sensory nerves act as an essential upstream mediator to promote angiogenesis, including the formation of type H vessels, and reparative dentinogenesis. CGRP signalling governs the nerve-vessel-reparative dentine network, which is mostly produced by newly dense sensory nerve fibres within the dental pulp.