Clinical and Molecular Perspectives of Reparative Dentin Formation: Lessons Learned from Pulp-Capping Materials and the Emerging Roles of Calcium

Histological Evaluation of Photobiomodulation and Calcium Aluminosilicate on Direct Pulp Capping of Dogs' Permanent Teeth

Introduction: Photobiomodulation (PBM) is beneficial to biological tissues; depending on the optical dose that is absorbed by tissues, it can function as a biostimulative, analgesic, and anti-inflammatory mediator. Thus, the current research aimed to assess the impacts of PBM and Calcium aluminosilicate-based material on direct pulp capping (DPC) of dogs' permanent teeth through histological analysis. Methods: To study DPC of dogs' teeth, we separated 24 canines and premolars obtained from mature, healthy mongrel dogs into four equal groups: group 1, which served as the control (exposed pulp was covered with a sterile polytetrafluoroethylene, Teflon tape); group 2, which received PBM treatment using a 980 nm diode laser with a 100 mw output power for one minute; group 3: Calcium aluminosilicate-based material; group 4: Calcium aluminosilicate+PBM. In accordance with the assessment period, each group was divided into three equal subcategories: (A) 1 week; (B) 2 months; (C) 3 months. The teeth were evaluated histologically for inflammatory response and dentine bridge formation. Results: Statistical analysis detected that there was a significant difference between PBM, Calcium aluminosilicate cement, and the combination group of PBM and Calcium aluminosilicate related to the control group in variant evaluation periods regarding the inflammatory response and dentine bridge thickness through the histological analysis. In relation to the inflammatory response after one week, the combined group (Calcium silicate cement+PBM) exhibited a significantly decreased intensity of inflammation compared to other groups at an identical time. As for dentin bridge creation, the PBM+calcium aluminosilicate group detected thicker dentine bridge creation at three months than other studied groups. Conclusion: Combined with calcium aluminosilicate-based material, PBM using a 980 nm diode laser with output power of 100 mw for one minute decreased the initial inflammatory response and enhanced a complete thick dentine bridge formation.

Effects of direct pulp capping with recombinant human erythropoietin and/or mineral trioxide aggregate on inflamed rat dental pulp

OBJECTIVE

This study aimed to evaluate the dental pulp responses to recombinant human erythropoietin (rhEPO) and/or mineral trioxide aggregate (MTA) in pulp capping of inflamed dental pulp in vivo.

MATERIALS AND METHODS

In accordance with ARRIVE guidelines, pulp inflammation was induced by exposing the maxillary first molars (n = 64) of Wistar rats (n = 32) to the oral environment for two days. The exposed pulps were randomly assigned four groups based on the pulp capping material: rhEPO, MTA, MTA + rhEPO, or an inert membrane. An additional eight rats formed the healthy control group. After four weeks, the animals were euthanized, and histological, qRT-PCR, and spectrophotometric techniques were employed to analyze the left maxillary segments, right first maxillary molars, and blood samples, respectively. Statistical significance was set at p < 0.05 and < 0.001.

RESULTS

Pulp capping with rhEPO, MTA, or MTA + rhEPO resulted in lower inflammation and higher mineralization scores compared to untreated control. MTA + rhEPO group exhibited significantly decreased expression of tumor necrosis factor-alpha, and interleukin 1-beta, while MTA group showed substantially reduced expression of interferon-gamma. Both rhEPO and MTA + rhEPO groups presented elevated dentin matrix protein 1 levels compared to untreated control. Furthermore, pulp capping with rhEPO and/or MTA led to increased transforming growth factor-beta 1 expression and reductions of pro-inflammatory/immunoregulatory cytokine ratios and prooxidative markers. Pulp capping with rhEPO also resulted in increase of systemic antioxidative stress markers.

CONCLUSION

Capping with rhEPO or MTA + rhEPO resulted in a favorable effect that was similar or even superior to that of MTA.

Correlation between tooth decay and insulin resistance in normal weight males prompts a role for myo-inositol as a regenerative factor in dentistry and oral surgery: a feasibility study

Background

In an era of precision and stratified medicine, homogeneity in population-based cohorts, stringent causative entry, and pattern analysis of datasets are key elements to investigate medical treatments. Adhering to these principles, we collected in vivo and in vitro data pointing to an insulin-sensitizing/insulin-mimetic effect of myo-inositol (MYO) relevant to cell regeneration in dentistry and oral surgery. Confirmation of this possibility was obtained by in silico analysis of the relation between in vivo and in vitro results (the so-called bed-to-benchside reverse translational approach).

Results

Fourteen subjects over the 266 screened were young adult, normal weight, euglycemic, sedentary males having normal appetite, free diet, with a regular three-times-a-day eating schedule, standard dental hygiene, and negligible malocclusion/enamel defects. Occlusal caries were detected by fluorescence videoscanning, whereas body composition and energy balance were estimated with plicometry, predictive equations, and handgrip. Statistically significant correlations (Pearson r coefficient) were found between the number of occlusal caries and anthropometric indexes predicting insulin resistance (IR) in relation to the abdominal/visceral fat mass, fat-free mass, muscular strength, and energy expenditure adjusted to the fat and muscle stores. This indicated a role for IR in affecting dentin reparative processes. Consistently, in vitro administration of MYO to HUVEC and Swiss NIH3T3 cells in concentrations corresponding to those administered in vivo to reduce IR resulted in statistically significant cell replication (ANOVA/Turkey tests), suggesting that MYO has the potential to counteract inhibitory effects of IR on dental vascular and stromal cells turnover. Finally, in in silico experiments, quantitative evaluation (WOE and information value) of a bioinformatic Clinical Outcome Pathway confirmed that in vitro trophic effects of MYO could be transferred in vivo with high predictability, providing robust credence of its efficacy for oral health.

Conclusion

Our reverse bed-to-benchside data indicate that MYO might antagonize the detrimental effects of IR on tooth decay. This provides feasibility for clinical studies on MYO as a regenerative factor in dentistry and oral surgery, including dysmetabolic/aging conditions, bone reconstruction in oral destructive/necrotic disorders, dental implants, and for empowering the efficacy of a number of tissue engineering methodologies in dentistry and oral surgery.

Long-Term Evaluation of Pulp Vitality Preservation in Direct and Indirect Pulp Capping: A Retrospective Clinical Study

Background: This retrospective clinical study aimed to assess dental pulp tissue reactions to direct and indirect pulp capping after 10 years of follow-up. Methods: A total of 276 permanent teeth with deep carious lesions were evaluated and divided into five groups: Group (1), direct pulp capping with Mineral Trioxide Aggregate cement; Group (2), direct pulp capping with a resin-based glass ionomer; Group (3), direct pulp capping with TheraCal; Group (4), indirect pulp capping with a three-step total-etch adhesive system; and Group (5), indirect pulp capping with a two-step self-etch adhesive system. Results: A 72.5% success rate was achieved overall. A statistically significant difference was found when comparing direct and indirect pulp capping with a success rate of 23.8% and 93.8%, respectively. For direct pulp-capping procedures, the area of pulp exposure was correlated with pulp necrosis (p = 0.035), while bleeding after exposure appeared independent (p = 0.053). Patient age was significantly related to the maintenance of pulp vitality (p = 0.013). A statistically significant correlation between the pulp-capping material and the occurrence of pulp necrosis was discovered (p = 0.017). For the indirect pulp-capping treatments, a significant correlation between patient age (p = 0.021) and the adhesive system (p = 0.019) with pulp necrosis was described. Conclusions: The pulp-capping material, patient age, and the width of the pulp exposure before the procedure should be carefully considered when performing direct pulp-capping treatments. The performance of the etch-and-rinse adhesive systems was superior to the self-etch system during the indirect pulp-capping procedures.

Comparative Clinical and Radiographic Success Rate of Bioceramic Premix vs Biosilicate-based Medicament as Indirect Pulp Treatment Materials in Primary Molars: A Double-blind Randomized Trial with a Follow-up of 12 Months

Aim

To evaluate and compare the clinical and radiographic success of NeoPUTTY® and Biodentine™ as indirect pulp treatment (IPT) materials in primary molars.

Materials and methods

This clinical trial was conducted on children aged 5-9 years. Class I carious lesions in primary molars indicated for IPT were divided into two groups-group I, NeoPUTTY®, and group II, Biodentine™. IPC was performed as per the standard protocols. The treated teeth were evaluated for clinical and radiographic success, along with the presence of a dentinal bridge at 6 and 12 months, by three blind examiners independently. All the data were tabulated, and statistical analysis was performed using the Mann-Whitney U test.

Results

Interexaminer reliability was analyzed using Fleiss κ statistics, and it showed "good" agreement. Clinical success was 100% in both groups at 6- and 12-month follow-up, while radiographic success was also 100% at 6-month follow-up for both groups. However, at 12-month follow-up, it was 93.33% for group I and 100% for group II. The difference was statistically nonsignificant. The presence of a dentinal bridge at 12-month follow-up was seen in 86.66% of cases in group I and 100% of cases in group II, but there was no statistical difference observed between them with a p-value of 0.555.

Conclusion

Within the limitations of the study, we conclude that NeoPUTTY® and Biodentine™ are equally effective as IPT agents in primary teeth.

How to cite this article

Kothari P, Mathur A, Tirupathi S, et al. Comparative Clinical and Radiographic Success Rate of Bioceramic Premix vs Biosilicate-based Medicament as Indirect Pulp Treatment Materials in Primary Molars: A Double-blind Randomized Trial with a Follow-up of 12 Months. Int J Clin Pediatr Dent 2024;17(7):748-753.

An animal study on the effectiveness of platelet-rich plasma as a direct pulp capping agent

Direct pulp capping (DPC) is a conservative approach for preserving tooth vitality without requiring more invasive procedures by enhancing pulp healing and mineralized tissue barrier formation. We investigated the effectiveness of Platelet Rich Plasma (PRP) vs. Mineral Trioxide Aggregate (MTA) as a DPC agent. Forty-two teeth from three mongrel dogs were divided into two equal groups. After three months, the animals were sacrificed to evaluate teeth radiographically using cone-beam computerized tomography, histopathologically, and real-time PCR for dentin sialophosphoprotein (DSPP), matrix extracellular phosphoglycoprotein (MEPE), and nestin (NES) mRNA expression. Radiographically, hard tissue formation was evident in both groups without significant differences (p = 0.440). Histopathologic findings confirmed the dentin bridge formation in both groups; however, such mineralized tissues were homogenous without cellular inclusions in the PRP group, while was osteodentin type in the MTA group. There was no significant difference in dentin bridge thickness between the PRP-capped and MTA-capped teeth (p = 0.732). The PRP group had significantly higher DSPP, MEPE, and NES mRNA gene expression than the MTA group (p < 0.05). In conclusion, PRP enables mineralized tissue formation following DPC similar to MTA, and could generate better cellular dentinogenic responses and restore dentin with homogenous architecture than MTA, making PRP a promising alternative DPC agent.

Outcome of novel pulp capping modalities after full pulpotomy in teeth diagnosed with irreversible pulpitis: A prospective randomized clinical trial

Objective

The study aimed to compare and evaluate the effect of biodentine (BD) alone, BD along with Lyophilised freeze dried platelet rich concentrate (LPC + BD), and BD along with low-level laser therapy (BD + LLLT) after pulpotomy in mature permanent molars with irreversible pulpitis.

Materials and Methods

The study was designed as a randomized, pragmatic, parallel, double-blinded clinical trial registered under the Clinical Trial Registry-India (CTRI/2020/02/023245). 120 permanent molars fulfilling the inclusion and exclusion criteria with symptoms of irreversible pulpitis were randomized after performing pulpotomy into three pulp capping groups: Group 1, BD; Group 2, lyophilized freeze-dried platelet-rich concentrate + BD (LPC + BD); and Group 3, Low level laser therapy + BD Group 3, LLLT + BD. The intergroup comparison was done using one-way analysis of variance followed by the Bonferroni test. The level of significance and confidence interval were 5% and 95%, respectively. Interobserver reliability was measured using Cohen's kappa analysis.

Results

At 1 week, there was a significant difference (P < 0.005) observed in the mean postoperative pain levels between the three groups with Group 1 (BD) exhibiting the highest postoperative pain followed by Group 2 (LPC + BD) and least pain was exhibited by Group 3 (LLLT + BD). A similar pattern was observed regarding the analgesic intake with maximum frequency in Group 1 (BD) and least with Group 3 (LLLT + BD). No significant difference in success rates was reported among the groups.

Conclusion

Pulpotomy as a treatment option for mandibular molars with irreversible pulpitis has an acceptable clinical success rate; however, long-term overall success rate remains questionable. The outcomes of incorporating adjunctive modalities with BD are remarkable and show tremendous potential for continued development and research.

Magnesium-Doped Nano-Hydroxyapatite/Polyvinyl Alcohol/Chitosan Composite Hydrogel: Preparation and Characterization

Background

Polyvinyl alcohol/Chitosan hydrogel is often employed as a carrier because it is non-toxic, biodegradable, and has a three-dimensional network structure. Meanwhile, Magnesium-doped nano-hydroxyapatite(Mg-nHA) demonstrated high characterization to promote the osteogenic differentiation of bone marrow derived mesenchymal stem cell(BMSCs). Therefore, in order to develop a porous hydrogel scaffold for the application of bone tissue engineering, an appropriate-type Mg-nHA hydrogel scaffold was developed and evaluated.

Methods

A composite hydrogel containing magnesium-doped nano-hydroxyapatite (Mg-nHA/PVA/CS) was developed using a magnetic stirring-ion exchange method and cyclic freeze-thaw method design, with polyvinyl alcohol and chitosan as the main components. Fourier transform infrared spectra (FTIR), electron energy dispersive spectroscopy (EDS), X-ray photoelectron spectrometer (XPS) and scanning electron microscopy (SEM) were employed to analyze the chemical structure, porosity, and elemental composition of each hydrogels. The equilibrium swelling degree, moisture content, pH change, potential for biomineralization, biocompatibility, the osteogenic potential and magnesium ion release rate of the composite hydrogel were also evaluated.

Results

SEM analysis revealed a well-defined 3D spatial structure of micropores in the synthesised hydrogel. FTIR analysis showed that doping nanoparticles had little effect on the hydrogel's structure and both the 5% Mg-nHA/PVA/CS and 10% Mg-nHA/PVA/CS groups promoted amide bond formation. EDS observation indicated that the new material exhibited favourable biomineralization ability, with optimal performance seen in the 5% Mg-nHA/PVA/CS group. The composite hydrogel not only displayed favourable water content, enhanced biocompatibility, and porosity (similar to human cancellous bone), but also maintained an equilibrium swelling degree and released magnesium ions that created an alkaline environment around it. Additionally, it facilitated the proliferation of bone marrow mesenchymal stem cells and their osteogenic differentiation.

Conclusion

The Mg-nHA/PVA/CS hydrogel demonstrates significant potential for application in the field of bone repair, making it an excellent composite material for bone tissue engineering.

A paradigm shift from calcium hydroxide to bioceramics in direct pulp capping: A narrative review

For many years, calcium hydroxide (CH) was the preferred material for direct pulp capping (DPC), occupying an elevated position. The collapse of this paradigm is due to the emergence of bioceramics with less pulpal inflammation and superior mineralization abilities than CH. The goal of the current article was directed to: (1) review the history of DPC "the idea of an exposed pulp as a hopeless organ has given way to one of healing and optimism," (2) classify the bioceramics in dentistry, and (3) explain and compare the mechanism by which dentin barriers for CH and bioceramics are formed. A comprehensive literature search of the database was conducted using PubMed, Google Scholar, and Scopus utilizing the following terms: Biodentine, calcium hydroxide, calcium aluminate, calcium phosphate, calcium silicate, direct pulp capping, NeoMTA Plus, Quick-Set2, and TotalFill. Reference mining of the selected publications was utilized to discover other studies and strengthen the results. Only works written in English were taken into consideration, and there were no restrictions on the year of publication. Bioceramic materials might be used as an intriguing substitute for CH. Compared to CH, they induced more positive pulpal reactions.

Direct pulp capping procedures - Evidence and practice

The aim of direct pulp capping (DPC) is to promote pulp healing and mineralized tissue barrier formation by placing a dental biomaterial directly over the exposed pulp. Successful application of this approach avoids the need for further and more extensive treatment. In order to ensure a complete pulp healing with the placement of restorative materials, a mineralized tissue barrier must form to protect the pulp from microbial invasion. The formation of mineralized tissue barrier can only be induced when there is a significant reduction in pulp inflammation and infection. Consequently, promoting the healing of pulp inflammation may provide a favorable therapeutic opportunity to maintain the sustainability of DPC treatment. Mineralized tissue formation was observed as the favorable reaction of exposed pulp tissue against a variety of dental biomaterials utilized for DPC. This observation reveals an intrinsic capacity of pulp tissue for healing. Therefore, this review focuses on the DPC and its healing procedure as well as the materials used for DPC treatment and their mechanisms of action to promote pulpal healing. In addition, the factors that can affect the healing process of DPC, clinical considerations and future perspective has been described.

Comparative evaluation of pH and Ca + ion release from MTA on interaction with platelet-rich fibrin and blood clot: an in vitro study

Background: 'Regenerative endodontics' using host-derived scaffolds and biomaterials (MTA) is popular in the management of teeth with open apex. Alkaline pH and bioactivity contribute to tissue healing and remineralization. We assessed the influence of PRF and Blood Clot on the pH and Ca + ion release from MTA. Methods: A total of 15 single-rooted human extracted teeth were sectioned at the level of the cementoenamel junction. Based on the type of scaffolds used, samples were divided into three groups. Group 1 (MTA+ PRF), Group 2 (MTA + Blood Clot), Group 3 (control MTA). The prepared specimens were transferred to a fresh falcon tube containing 10mL of distilled water and the collected solutions were analysed for pH and Ca + ion release at 3h, seventh day and 14 th day. Results: It was observed that the mean pH and Ca + ion release were significantly lower in the experimental groups as compared to the control group. Though there was an increase in the pH recorded in Group 1 and 2 at all time periods, the difference was not significant. Ca + ion release peaked at Day 7 (Group3 > Group2 > Group1) and reduced significantly on the 14 th day for all groups. Conclusions: Within the limitations of the study, it can be concluded that PRF and blood clot influence the pH and Ca + ion release from MTA.

Mesenchymal condensation in tooth development and regeneration: a focus on translational aspects of organogenesis

The teeth are vertebrate-specific, highly specialized organs performing fundamental functions of mastication and speech, the maintenance of which is crucial for orofacial homeostasis and is further linked to systemic health and human psychosocial well-being. However, with limited ability for self-repair, the teeth can often be impaired by traumatic, inflammatory, and progressive insults, leading to high prevalence of tooth loss and defects worldwide. Regenerative medicine holds the promise to achieve physiological restoration of lost or damaged organs, and in particular an evolving framework of developmental engineering has pioneered functional tooth regeneration by harnessing the odontogenic program. As a key event of tooth morphogenesis, mesenchymal condensation dictates dental tissue formation and patterning through cellular self-organization and signaling interaction with the epithelium, which provides a representative to decipher organogenetic mechanisms and can be leveraged for regenerative purposes. In this review, we summarize how mesenchymal condensation spatiotemporally assembles from dental stem cells (DSCs) and sequentially mediates tooth development. We highlight condensation-mimetic engineering efforts and mechanisms based on ex vivo aggregation of DSCs, which have achieved functionally robust and physiologically relevant tooth regeneration after implantation in animals and in humans. The discussion of this aspect will add to the knowledge of development-inspired tissue engineering strategies and will offer benefits to propel clinical organ regeneration.

Biodentine but not MTA induce DSPP expression of dental pulp cells with different severity of LPS-induced inflammation

OBJECTIVES

To explore the inflammatory and differentiation response in inflamed dental pulp cells (DPCs) induced by lipopolysaccharide (LPS) under different conditions with Biodentine and mineral trioxide aggregate (MTA) treatment.

MATERIALS AND METHODS

DPCs were treated with 0.001-1 µg/mL LPS for different periods to induce inflammation. Normal and inflamed DPCs were further treated with 0.14 mg/mL Biodentine or 0.13 mg/mL MTA for different periods. mRNA expression level of IL-6, IL-8 and ALP were analysed by qPCR. DSPP protein expression was detected by western blot. The data were analysed by the Mann-Whitney test, unpaired t test or two-way ANOVA.

RESULTS

After treatment for different times and with different concentrations of LPS, different severity of pulp inflammation was revealed by the expressions of IL-6 and IL-8. Higher concentrations of LPS induced higher IL-6 and IL-8 expressions, and these expressions first increased and then decreased (p < 0.0001). At 96 and 192 h, Biodentine significantly suppressed IL-6 expression in both normal and inflamed DPCs (p < 0.05). At 48 and 96 h, Biodentine suppressed ALP expression in both normal and inflamed DPCs (p < 0.05). At 48 and 96 h, Biodentine induced DSPP expressions in both normal and inflamed DPCs (p < 0.05).

CONCLUSION

Biodentine enhanced more DSPP differentiation of both normal and inflamed DPCs under different treatment durations than MTA.

CLINICAL RELEVANCE

The prognosis of vital pulp therapy may depend on the severity of pulp inflammation which is difficult to be determined in clinical settings. Therefore, Biodentine may enhance odontogenic differentiation in different severity of pulp inflammation imply its clinical indications.

Genome wide analysis of dexamethasone stimulated mineralization in human dental pulp cells by RNA sequencing

Human dental pulp cells (hDPCs) contain mesenchymal stem cells and are therefore indispensible for reparative dentin formation. Here, we present a pilot study of transcriptomic profiles of mineralized hDPCs isolated from sound human maxillary third molars. We observed altered gene expression of hDPCs between control (dexamethasone free) and experimental (dexamethasone 1 nm) groups. Differential expression analysis revealed up-regulation of several inflammation and mineralization-related genes in the experimental group. After a Gene Ontology analysis for predicting genes involved in biological process, cellular component and molecular function, we found enrichment of genes related to protein binding. Based on the results of Kyoto Encylopedia of Genes and Genomes pathway analysis, it is suggested up-regulated genes in mineralized hDPCs were mostly enriched in the mitogen-activated protein kinase (MAPK) signaling pathway, fluid shear stress and the atherosclerosis signaling pathway, etc. Importantly, Gene Set Enrichment Analysis revealed dexamethasone was positively related to the Janus kinase/signal transducer and activator of transcription, MAPK and Notch signaling pathway. Moreover, it was suggested that dexamethasone regulates signaling pathway in pluripotency of stem cells. Collectively, our work highlights transcriptome level gene regulation and intercellular interactions in mineralized hDPCs. The database produced in the present study paves the way for further investigations looking to explore genes that are involved in dental pulp cells mineralization.

Analysis of Pulp Tissue Viability and Cytotoxicity of Pulp Capping Agents

The present research study assessed the cell viability and cytotoxic effect of mineral tri-oxide aggregate (MTA), Tetric N-Bond Universal bonding agent, Theracal PT (pulpotomy treatment), and platelet-rich fibrin (PRF) as pulp capping agents on human dental pulp stem cells (hDPSCs). The cells were isolated from the pulp tissue of an extracted healthy permanent third molar. After four passages in Dulbecco’s Modified Eagle’s Medium, the primary cells were employed for the investigation. The test materials and untreated cells (negative control) were subjected to an Methylthiazol-diphenyl-tetrazolium (MTT) cytotoxicity assay and assessed at 24-, 48-, and 72-h intervals. The Wilcoxon matched-paired t-test and Kruskal−Wallis analysis of variance (ANOVA) test were applied (p < 0.05). PRF imparted the highest cell viability at 48 h (p < 0.001), followed by MTA, Theracal PT, and Tetric N-Bond. Similarly, PRF had the highest potential to enhance cell proliferation and differentiation (p < 0.001), followed by Theracal PT, MTA, and the bonding agent at the end of 24 h and 72 h, respectively. Finally, PRF sustained the viability of human primary dental pulp stem cells more effectively than Theracal PT and MTA; however, the application of a Tetric N-Bond as a pulp capping agent was ineffective.

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

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 <0.05) values of pro-oxidative parameters and lower (p <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.

Evaluation of Cytotoxic Effect of Graphene Oxide Added to Mineral Trioxide Aggregate

Aim:

Recently, although studies have shown that biomaterials containing graphene oxide (GO) in biomedicine stand out for their positive effects, the effect of GO on dental tissues when used with dental materials is not well known. The aim of this study was an evaluation of the cytotoxic effects of GO on gingival fibroblasts when it is combined in two different ratios with Mineral Trioxide Aggregate (MTA).

Materials and Methods:

In this in-vitro study, a homogenous mixture of adding +0.1 weight (wt)% and +0.3 wt% GO to Angelus MTA was created (two experimental groups) and compared with pure Angelus MTA and negative control groups. The materials were mixed according to the manufacturer’s instructions, and Teflon molds were used to form 24 disc-shaped samples for each group. The samples were divided into groups according to the simple random sampling method. The cytotoxic effect of samples was determined on gingival fibroblast cells by using the MTT test, and total oxidant status (TOS) and total antioxidant capacity (TAC) kits in 24 and 72 hours. The data were statistically analyzed using one-way ANOVA and Tukey tests.

Results:

A significant difference was found between the material-applied groups and the control group at the TAC 24 and 72 hours and between the groups containing GO and the control group at the MTT 72 hours and TAC and TOS 24 and 72 hours ( p < .05).

Conclusion:

The addition of GO to MTA increased the dose and time-based toxicity and oxidant amount, and decreased antioxidant capacity.

Push-Out Bond Strength and Dentinal Penetration of a Novel Herbal-Based Pulp Capping Agent: An In vitro Study

Background: Pulp capping agents should have proper sealing effect to enhance dental pulp tissue healing. Aim: The purpose of this study was to compare the effectiveness of grape seed extract (GSE) and Mineral trioxide aggregate (MTA) to penetrate to dentin and their push-out bond strength at two time intervals (1 and 3 months) when used as pulp capping agents either singly or combined to each other. Materials and Methods: This study was conducted on 120 human single-rooted anterior teeth. Sixty dentin discs were randomly divided into three groups (n=20) based on the material used; MTA, GSE, and a combination of MTA and GSE. A universal testing machine was used to determine the push-out bond strength for one and three months. At the same time intervals, extra 60 teeth with the same groups were utilized to quantify the degree of capping material penetration within the dentinal tubules using scanning electron microscopy (SEM). ANOVA with multiple comparison Post hoc test was used to evaluate the data where the p value was < 0.05. Results: MTA had the highest push-out bond strength and penetration depth measurement into dentinal tubules at one month, followed by MTA combined with GSE, while GSE had the lowest push-out bond strength and penetration depth measurement. Nevertheless, GSE had the greatest values in both tests at 3 months, followed by MTA, while MTA coupled with GSE had the lowest value in both tests. Conclusion: Push out bond strength and dentinal penetration depth were improved with time except for the MTA group testing its dentinal penetration depth. GSE shows good push out bond strength and dentinal penetration depth.

Vitronectin-Derived Peptide Promotes Reparative Dentin Formation

Exposed dental pulp can maintain its vitality through a pulp-capping procedure with biocompatible materials, followed by reparative dentin formation. Our previous study demonstrated that a vitronectin-derived peptide (VnP-16) promotes osteoblast differentiation and concomitantly restrains osteoclast differentiation and resorptive function. In this study, we aimed to demonstrate that VnP-16 promotes odontoblast differentiation, mineralization, and reparative dentin formation in a pulp exposure model using a rat tooth. VnP-16 showed no cytotoxicity and promoted cellular behavior in human dental pulp cells, enhancing their differentiation into odontoblast-like cells and mineralization, effects that are comparable to those obtained with vitronectin. In a rat pulp exposure model, VnP-16 showed mild inflammatory responses at 2 and 4 wk or none. Mineral trioxide aggregate (MTA) demonstrated a tendency of early formation of reparative dentin at 2 wk when compared with recombinant human bone morphogenetic protein 2 (rhBMP-2) and VnP-16. However, VnP-16 induced reparative dentin formation similar to MTA and rhBMP-2 without inflammation at 4 wk. In addition, VnP-16 showed a thicker and homogeneous reparative dentin formation versus MTA and rhBMP-2. Collectively, these results suggest that VnP-16 can be a useful, direct pulp-capping agent for highly qualified reparative dentin formation by promoting cell behavior and odontoblastic differentiation of human dental pulp cells.

Expert consensus on dental caries management

Dental Caries is a kind of chronic oral disease that greatly threaten human being's health. Though dentists and researchers struggled for decades to combat this oral disease, the incidence and prevalence of dental caries remain quite high. Therefore, improving the disease management is a key issue for the whole population and life cycle management of dental caries. So clinical difficulty assessment system of caries prevention and management is established based on dental caries diagnosis and classification. Dentists should perform oral examination and establish dental records at each visit. When treatment plan is made on the base of caries risk assessment and carious lesion activity, we need to work out patient‑centered and personalized treatment planning to regain oral microecological balance, to control caries progression and to restore the structure and function of the carious teeth. And the follow-up visits are made based on personalized caries management. This expert consensus mainly discusses caries risk assessment, caries treatment difficulty assessment and dental caries treatment plan, which are the most important parts of caries management in the whole life cycle.

Effect of Magnesium on Dentinogenesis of Human Dental Pulp Cells

Introducing therapeutic ions into pulp capping materials has been considered a new approach for enhancing regeneration of dental tissues. However, no studies have been reported on its dentinogenic effects on human dental pulp cells (HDPCs). This study was designed to investigate the effects of magnesium (Mg2+) on cell attachment efficiency, proliferation, differentiation, and mineralization of HDPCs. HDPCs were cultured with 0.5 mM, 1 mM, 2 mM, 4 mM, and 8 mM concentrations of supplemental Mg2+ and 0 mM (control). Cell attachment was measured at 4, 8, 12, 16, and 20 hours. Cell proliferation rate was evaluated at 3, 7, 10, 14, and 21 days. Crystal violet staining was used to determine cell attachment and proliferation rate. Alkaline phosphatase (ALP) activity was assessed using the fluorometric assay at 7, 10, and 14 days. Mineralization of cultures was measured by Alizarin red staining. Statistical analysis was done using multiway analysis of variance (multiway ANOVA) with Wilks' lambda test. Higher cell attachment was shown with 0.5 mM and 1 mM at 16 hours compared to control (P < 0.0001). Cells with 0.5 mM and 1 mM supplemental Mg2+ showed significantly higher proliferation rates than control at 7, 10, 14, and 21 days (P < 0.0001). However, cell proliferation rates decreased significantly with 4 mM and 8 mM supplemental Mg2+ at 14 and 21 days (P < 0.0001). Significantly higher levels of ALP activity and mineralization were observed in 0.5 mM, 1 mM, and 2 mM supplemental Mg2+ at 10 and 14 days (P < 0.0001). However, 8 mM supplemental Mg2+ showed lower ALP activity compared to control at 14 days (P < 0.0001), while 4 mM and 8 mM supplemental Mg2+showed less mineralization compared to control (P < 0.0001). The study indicated that the optimal (0.5-2 mM) supplemental Mg2+ concentrations significantly upregulated HDPCs by enhancing cell attachment, proliferation rate, ALP activity, and mineralization. Magnesium-containing biomaterials could be considered for a future novel dental pulp-capping additive in regenerative endodontics.

Graphene oxide-coated porous titanium for pulp sealing: an antibacterial and dentino-inductive restorative material

Pulp treatment techniques such as pulp capping, pulpotomy and pulp regeneration are all based on the principle of preserving vital pulp. However, specific dental restorative materials that can simultaneously protect pulp vitality and repair occlusal morphology have not been developed thus far. Traditional pulp capping materials cannot be used as dental restorative materials due to their long-term solubility and poor mechanical behavior. Titanium (Ti) is used extensively in dentistry and is regarded as a promising material for pulp sealing because of its favorable biocompatibility, processability and mechanical properties. Originally, we proposed the concept of "odontointegration", which represents direct dentin-like mineralization contact between pulp and the surface of the pulp sealing material; herein, we report the fabrication of a novel antibacterial and dentino-inductive material via micro-arc oxidation (MAO), incorporating self-assembled graphene oxide (GO) for Ti surface modification. The hierarchical micro/nanoporous structure of the MAO coating provides a suitable microenvironment for odontogenic differentiation of human dental pulp stem cells, and GO loading contributes to antibacterial activity. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy and Raman spectroscopy were employed for structure and elemental analysis. In vitro studies, including cell adhesion, Live/Dead and CCK-8 assays, alkaline phosphatase activity and calcium deposition assay, real-time polymerase chain reaction, western blot analysis and immunofluorescence staining were used to examine cell adhesion, viability, proliferation, mineralization, and odontogenic differentiation ability. Antibacterial properties against Streptococcus mutans were analyzed by SEM, spread plate, Live/Dead and Alamar blue tests. The Ti-MAO-1.0 mg mL-1 GO group exhibited excellent cell adhesion, odontoblast differentiation, mineralization, and antibacterial ability, which are beneficial to odontointegration.

Therapeutic applications of dental pulp stem cells in regenerating dental, periodontal and oral-related structures

Dental pulp stem cells (DPSCs) have emerged as a promising tool with great potential for use in tissue regeneration and engineering. Some of the main advantages of these cells are their multifaceted differentiation capacity, along with their high proliferation rate, a relative simplicity of extraction and culture that enables obtaining patient-specific cell lines for their use in autologous cell therapy. PubMed, Scopus and Google Scholar databases were searched for relevant articles related to the use of DPSCs in regeneration of dentin-pulp complex (DPC), periodontal tissues, salivary gland and craniomaxillofacial bone defects. Few studies were found regarding the use of DPSCs for regeneration of DPC. Scaffold-based combined with DPSCs isolated from healthy pulps was the strategy used for DPC regeneration. Studies involved subcutaneous implantation of scaffolds loaded with DPSCs pretreated with odontogenic media, or performed on human tooth root model as a root slice. Most of the studies were related to periodontal tissue regeneration which mainly utilized DPSCs/secretome. For periodontal tissues, DPSCs or their secretome were isolated from healthy or inflamed pulps and they were used either for preclinical or clinical studies. Regarding salivary gland regeneration, the submandibular gland was the only model used for the preclinical studies and DPSCs or their secretome were isolated only from healthy pulps and they were used in preclinical studies. Likewise, DPSCs have been studied for craniomaxillofacial bone defects in the form of mandibular, calvarial and craniofacial bone defects where DPSCs were isolated only from healthy pulps for preclinical and clinical studies. From the previous results, we can conclude that DPSCs is promising candidate for dental and oral tissue regeneration.

Minimal Intervention in Dentistry: A Literature Review on Biodentine as a Bioactive Pulp Capping Material

Root canal treatment has been the treatment of choice for carious pulp exposures. In the perspective of minimally invasive dentistry and preventive endodontics, a direct pulp capping procedure with a reliable bioactive material may be considered an alternative approach provided that the pulp status is favorable. However, the treatment of pulp exposure by pulp capping is still a controversial issue with no clear literature available on this topic, leaving the concerned practitioner more confused than satisfied. Biodentine is a relatively new bioactive material explored for vital pulp therapy procedures. This article discusses its role in direct pulp capping procedures. A thorough literature search of the database was done using PubMed, Google Scholar, and Scopus using the keywords preventive endodontics, calcium silicate cement, direct pulp capping, Biodentine, and vital pulp therapy. Reference mining of the articles that were identified was used to locate other papers and enrich the findings. No limits were imposed on the year of publication, but only articles in English were considered. This paper is aimed at reviewing the current literature on Biodentine as a direct pulp capping material. The review will provide a better understanding of Biodentine's properties and can aid in the decision-making process for maintaining the vitality of exposed dental pulp with minimal intervention.

A novel bio-active adhesive monomer induces odontoblast differentiation: a comparative study

AIM

To evaluate the in vitro effect of the novel adhesive monomer CMET, a calcium salt of 4-methacryloxyethyl trimellitate (4-MET), on the proliferation, mineralization and differentiation of odontoblast-like cells, comparing with 4-MET, calcium hydroxide (CH) and mineral trioxide aggregate (MTA).

METHODOLOGY

Rat odontoblast-like MDPC-23 cells were cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with 5% foetal bovine serum. The powder of four tested materials (CMET, 4-MET, CH and MTA) was first dissolved in distilled water (dH₂O) and then was diluted by DMEM to yield final concentrations. Solvent (dH₂O) was used as a control. Cell viability was assessed using CCK-8 assay. Real-time RT-PCR was used to quantify the mRNA expression of odontogenic markers, cytokines and integrins. Mineralization inducing capacity was evaluated by alkaline phosphatase (ALPase) activity and alizarin red S staining. Statistical analyses were performed using one-way anova and post hoc Tukey's HSD test, with the significance level at 1%.

RESULTS

Cell viability was significantly greater in the CMET- (83 to 828 mmol L^-1), CH- and MTA-treated (low concentrations) groups than that in the control group (P < 0.01). Higher concentrations of each material decreased the viable cells to different extents (P < 0.01). CMET treatment augmented the expression of several integrin subunits and exhibited the highest mRNA expression levels of odontogenic markers among all groups (P < 0.01). CH and MTA treatment caused significantly greater upregulation of pro-inflammatory cytokines expression than the other groups (P < 0.01). The calcific deposition of MDPC-23 cells was dose-dependently accelerated by the addition of CMET (P < 0.01); the enhancement of mineralization was also found in the fresh prepared CH and MTA treatments. Besides, CMET showed consistency in mineralization induction after 8 weeks storage. Exposure to SB202190, a specific p38 mitogen-activated protein kinases inhibitor, significantly decreased the ALPase activity as well as the mineral deposition which was enhanced by CMET treatment (P < 0.01).

CONCLUSIONS

The novel bio-active monomer had the lowest cytotoxicity among all groups and it induced the proliferation, mineralization and differentiation of odontoblast-like cells under appropriate concentrations. This adhesive monomer possesses excellent biocompatibility and hence exhibits great potential in dentine regeneration.

Microscopic and elemental characterization of hydrated dental pulp capping agents

Context:

Characteristics of dental pulp capping agents may influence its interaction with the pulpal cells and can impact the treatment outcome.

Aims:

This study aims to microscopically characterize various pulp capping agents following hydration.

Settings and Design:

Original research.

Materials and Methods:

Disk-shaped specimens of five calcium silicate-based materials, i.e., mineral trioxide aggregate (MTA) Angelus, Biodentine, TheraCal LC, ApaCal ART, and Endocem MTA were prepared. After final set, the materials were immersed in 10 mL of deionized water for 14 days at 37°C. The set materials were characterized by scanning electron microscopy (SEM), X-ray energy dispersive analysis (EDX), and X-ray diffraction (XRD) analysis along with pH analysis of the storage solution using pH meter.

Results:

On SEM analysis, all the materials showed crystalline deposition on the cement surface with Biodentine exhibiting the most dense and homogenous microstructure. Calcium-silicate-hydrate and calcium hydroxide (CH) were observed as dark-grey and light-grey matrix material, respectively. EDX analysis revealed a high concentration of calcium. The other major elements were oxygen and carbon. The surface calcium concentration in the tested specimens was as follows: Biodentine (42.59 wt.%) > MTA Angelus (38.51wt.%) > Endocem MTA (30.24wt.%) > TheraCal LC (27.51wt.%) > ApaCal ART (22.02wt.%). On XRD analysis, all the materials exhibited peaks for tricalcium silicate and CH, after 14 days of hydration.

Conclusions:

The higher surface calcium level in Biodentine and MTA Angelus may enhance reparative dentin formation. The surface calcium concentration of Endocem MTA and ApaCal ART was found to be lesser than that of MTA Angelus, but with the added advantage of fast-setting property. Hence, they are potential alternative materials for vital pulp therapy.

Potential Roles of Bone Morphogenetic Protein 9 in the Odontogenic Differentiation of Dental Pulp Cells

INTRODUCTION

The differentiation of dental pulp cells (DPCs) plays an important role in the repair of dental pulp injury. Bone morphogenetic protein 9 (BMP9) is one of the most effective BMPs to induce the differentiation of stem cells. However, the role of BMP9 in promoting the odontogenic differentiation of DPCs and dentinogenesis is worth knowing.

METHODS

Fluorescence in situ hybridization and immunohistochemistry staining were performed to detect the BMP9 expression in human dental pulp. BMP9 was overexpressed in human DPCs (hDPCs), and the mineralization of hDPCs was tested by alkaline phosphatase staining and alizarin red staining. The expression of odontogenic differentiation-related genes was examined by quantitative real-time polymerase chain reaction and western blotting. The subcutaneous transplantation experiment was performed to test the odonto-induction ability of BMP9 in vivo. The rat direct pulp-capping experiment was performed to test the function of BMP9 in promoting dentin formation.

RESULTS

BMP9 showed an increased expression in odontoblast layer at both the mRNA and protein levels. BMP9 enhanced the mineralization and induced the expression of odontogenic differentiation-related genes in hDPCs. More mineralized nodules, and increased expression of dentin sialophosphoprotein (DSPP) and dentin matrix protein-1 (DMP1) were detected in the beta-tricalcium phosphate scaffold/cells composites of BMP9 group compared with the control group. Meanwhile, there was thicker reparative dentin formation in the BMP9 group in the rat pulp exposure experiment.

CONCLUSIONS

BMP9 participates in the process of DPC differentiation and promotes DPC mineralization and dentinogenesis. BMP9 might be a potential therapeutic target in the repair of dental pulp injury.

Expression of CaV3.1 T-type Calcium Channels in Acutely Isolated Adult Rat Odontoblasts

OBJECTIVE

Odontoblasts, which consist the outermost compartment of the dental pulp, are primarily engaged in dentin formation. Earlier evidence suggests that voltage-gated calcium channels, such as the high voltage-activated L-type calcium channels, serve as a calcium entry route to mediate dentin formation in odontoblasts. However, the involvement of other voltage-gated calcium channels in regulating intracellular Ca²⁺ remain unanswered.

DESIGN

The expression of voltage-gated calcium channel subtypes of the P/Q- (Ca_V2.1), N-(Ca_V2.2), R- (Ca_V2.3), and T- (Ca_V3.1-3.3) type were screened in adult rat odontoblasts by single cell RT-PCR. Among these candidates, immunopositivity against Ca_V3.1 was examined in the odontoblastic layer in teeth sections and dissociated odontoblasts. To confirm the functional expression of Ca_V3.1 in odontoblasts, intracellular Ca²⁺ increase in response to membrane depolarization was monitored with Fura-2-based ratiometric calcium imaging.

RESULTS

Among the candidate calcium channels, we found that mRNA for Ca_V3.1 is mainly detected in odontoblasts, with its expression being detected in the odontoblastic layer and dissociated odontoblasts. High extracellular K⁺-induced membrane depolarization was inhibited by pharmacological blockers for T-type calcium channels such as amiloride or ML218.

CONCLUSION

Our results demonstrate that among P/Q-, N-, R-, and T-type calcium channels, Ca_V3.1 is mainly expressed in odontoblasts to mediate intracellular Ca²⁺ signaling in response to membrane depolarization. These findings suggest that Ca_V3.1 may facilitate intracellular Ca²⁺ dynamics especially in the range of subliminal depolarizations near resting membrane potentials where other high voltage-gated calcium channels such as the L-type are likely to be inactive.

CaSR as a Therapeutic Target and Tool in Human Dental Pulp: A Concise Review and Novel Hypothesis

PURPOSE

To review the essential characteristics of calcium sensing receptor (CaSR) and explore the hypothesis that elevated extracellular calcium ions (Ca2+) may affect the odontogenic/osteogenic differentiation and mineralisation of human dental pulp cells (hDPCs) through the CaSR signal.

MATERIALS AND METHODS

Based on a literature search of databases using different combinations of the key words and our previous researches, we gleaned the following important viewpoints.

RESULTS

The Ca2+ released from pulp capping materials plays an essential role in maintaining the viability and function of human dental pulp, and elevated extracellular Ca2+ concentrations can promote the odontogenic/osteogenic differentiation and mineralisation of hDPCs. Ca2+ is the primary physiological ligand of the CaSR, which has been reported to be widely expressed in a broad range of cells, including various osteoblast-like cell lines, osteoprogenitor cells, and mature osteoblasts. hDPCs consist of different subpopulations and have been shown to share phenotypical features with osteoblasts. Thus, we speculated that hDPCs also express CaSR and respond to extracellular Ca2+ via this receptor. Calcimimetics are indirect allosteric regulators of CaSR function and can increase the receptor's sensitivity to ambient Ca2+.

CONCLUSION

The local use of calcimimetics and calcium-based pulp capping materials could create an option for promoting the Ca2+ influx of hDPCs from the extracellular space via the CaSR. Such elevated Ca2+ concentrations could enhance the odontogenic/osteogenic differentiation and mineralisation of hDPCs and eventually improve the success rate of direct pulp capping treatments in patients suffering from accidental dental pulp exposure.

Electrospinning of dexamethasone/cyclodextrin inclusion complex polymer fibers for dental pulp therapy

Beta-cyclodextrin (β-CD) is an oligosaccharide commonly used to improve the aqueous solubility of lipophilic drugs (e.g., dexamethasone, DEX). Here we present the development of a drug delivery system to provide sustained release of DEX by β-CD-inclusion complex (IC) to amplify the mineralization capacity of stem cells from human-extracted deciduous teeth (SHEDs) as a potential direct pulp capping strategy. First, IC of DEX (DEX-CD-IC) was synthesized with β-CD. To confirm DEX-CD-IC complex formation, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses were performed. XRD data indicated that IC formation was achieved due to formation of a new crystalline structure, whereas FTIR revealed the presence of the IC from the shifting of the peaks of each component in DEX-CD-IC. Then, electrospun poly(lactic-co-glycolic acid, PLGA) fibers (PLGA/DEX-CD-IC) were processed by varying the concentration of DEX-CD-IC (5%, 10 %, and 15 %). The release of DEX from fibers was determined by ultraperformance liquid chromatography for 28 days. Thanks to the solubility enhancement of DEX by IC, electrospun PLGA/DEX-CD-IC fibers released DEX in a more sustained fashion compared to PLGA/DEX fibers. No deleterious effect was found in terms of SHEDs' proliferation when cultured with or on electrospun fibers, regardless of the IC presence. Importantly, a more pronounced odontogenic differentiation was stimulated by electrospun fibers loaded with the lowest DEX-CD-IC concentration (5%), as a result of the sustained DEX release. In sum, PLGA/DEX-CD-IC fibers have great potential in vital dental pulp therapy, owing to its sustained DEX release, cytocompatibility, and odontogenic differentiation capacity.

Evaluation of dentinogenesis inducer biomaterials: an in vivo study

When exposure of the pulp to external environment occurs, reparative dentinogenesis can be induced by direct pulp capping to maintain pulp tissue vitality and function. These clinical situations require the use of materials that induce dentin repair and, subsequently, formation of a mineralized tissue. Objective: This work aims to assess the effect of tricalcium silicate cements and mineral trioxide aggregate cements, including repairing dentin formation and inflammatory reactions over time after pulp exposure in Wistar rats. Methodology: These two biomaterials were compared with positive control groups (open cavity with pulp tissue exposure) and negative control groups (no intervention). The evaluations were performed in three stages; three, seven and twenty-one days, and consisted of an imaging (nuclear medicine) and histological evaluation (H&E staining, immunohistochemistry and Alizarin Red S). Results: The therapeutic effect of these biomaterials was confirmed. Nuclear medicine evaluation demonstrated that the uptake of ^99mTc-Hydroxymethylene diphosphonate (HMDP) showed no significant differences between the different experimental groups and the control, revealing the non-occurrence of differences in the phosphocalcium metabolism. The histological study demonstrated that in mineral trioxide aggregate therapies, the presence of moderate inflammatory infiltration was found after three days, decreasing during follow-ups. The formation of mineralized tissue was only verified at 21 days of follow-up. The tricalcium silicate therapies demonstrated the presence of a slight inflammatory infiltration on the third day, increasing throughout the follow-up. The formation of mineralized tissue was observed in the seventh follow-up day, increasing over time. Conclusions: The mineral trioxide aggregate (WhiteProRoot^®MTA) and tricalcium silicate (Biodentine™) present slight and reversible inflammatory signs in the pulp tissue, with the formation of mineralized tissue. However, the exacerbated induction of mineralized tissue formation with the tricalcium silicate biomaterial may lead to the formation of pulp calcifications

Shear Bond Strength of Nanohybrid Composite to Biodentine with Three Different Adhesives

Biodentine® is a bioactive dentin coating widely used for dental restoration; however, its adhesion to the substrate could limit its clinical success. The aim of this study was to evaluate the shear bond strength (SBS) between Biodentine® and a composite resin, using different types of adhesive. In total, 120 acrylic blocks with a central hole were prepared. They were fully filled with Biodentine®, and divided into two time groups: 12 min (n = 60) and 24 h (n = 60); each group was subdivided into four groups according to the adhesive: three-step etch and rinse (3-E&R) (n = 15), two-step etch and rinse (n = 15), and a universal adhesive subdivided into two groups, two-step etch and rinse (n = 15) and one-step self-etch adhesive system (n = 15). After adhesive application, the composite was applied and stored at 100% humidity, at 37 °C, for 24 h, before the SBS test. Data were analyzed with one-way ANOVA, Fisher post hoc test, and Kolmogorov–Smirnov test. The 12-min group showed statistically significant differences (p = 0.009), with the highest values of adhesion for 3-E&R. No statistically significant differences were observed for the 24-h group (p = 0.813) and between adhesive systems (p = 0.071) regardless of adhesion time. Higher adhesion values were found at 24 h. It is essential to consider the longest setting time for Biodentine®. In terms of adhesive, 3-E&R had the highest adhesion values.

Human pulp response to conventional and resin-modified glass ionomer cements applied in very deep cavities

OBJECTIVES

This study assessed the human pulp response after adhesive restoration of cavities by indirect pulp capping with a conventional or a resin-modified glass ionomer cement.

MATERIALS AND METHODS

Deep cavities prepared in 26 human premolars were lined with Riva Light Cure (Riva LC), Riva Self Cure (Riva SC), or Dycal, and then restored with composite resin. Four teeth were used as intact control. After time intervals of 7 or 30 days, the teeth were extracted, processed for histological evaluation of the pulp, and the remaining dentin thickness (RDT) between the cavity floor and the pulp was measured.

RESULTS

At 7 days, a slight pulp inflammation associated with discrete tissue disorganization was observed in most of t the teeth lined with Riva LC and Riva SC. Moderate pulp inflammation occurred in one tooth lined with Riva LC. Bacteria were identified in one specimen of the same group that exhibited no pulp damage. At 30 days, slight pulp inflammation and discrete tissue disorganization persisted in two specimens treated with Riva LC, in which a thin layer of tertiary dentin was deposited. Mean RDTs ranged from 383.0 to 447.8 μm.

CONCLUSIONS

Riva LC produced more damage to the pulp than Riva SC. However, the initial pulp damage decreased over time and after 30 days both GICs were labeled as biocompatible.

CLINICAL RELEVANCE

In this study conducted with human teeth, the conventional and the resin-modified glass ionomer cements investigated were shown not to cause post-operative sensitivity or persistent pulp damage when applied as liners in very deep cavities, thereby indicating their biocompatibility.

Mineralogical and Microstructural Characteristics of Two Dental Pulp Capping Materials

This paper aims to investigate the composition, surface, and microstructural characteristics, and bioactivity of two commercially available pulp capping materials known as TheraCal LC and BIO MTA+. The materials were prepared as cylindrical samples and assessed by X-ray diffraction (XRD) and complex thermal analysis for mineralogical characterization, and by scanning electron microscopy (SEM) coupled with energy dispersive of X-ray (EDX), Fourier-Transformed Infrared Spectroscopy (FT-IR), and atomic force microscopy (AFM) for microstructural and surface characteristics. The in vitro bioactivity was highlighted by surface mineralization throughout SEM coupled with EDX and FT-IR analysis. XRD analysis performed on both materials showed calcium silicate phases and different radiopacifying compounds. AFM measurements indicated a smoother and more homogenous surface with a lower average roughness for TheraCal LC due to the resin matrix from its composition. FT-IR analysis displayed bands for several compounds in both materials. Both materials exhibited bioactive properties showing surface mineralization after being immersed in solution similar to the human physiological environment. However, the MTA cement showed a better mineralization due to the anhydrous and hydrated phases.

Biodentine™ Boosts, WhiteProRoot®MTA Increases and Life® Suppresses Odontoblast Activity

(1) Background: When pulp exposure occurs, reparative dentinogenesis can be induced by direct pulp capping to maintain the vitality and function of the tissue. The aim of this work was to assess the cytotoxicity and bioactivity of three different direct pulp capping materials, calcium hydroxide (Life^®), mineral trioxide aggregate (WhiteProRoot^®MTA) and calcium silicate (Biodentine^™), in an odontoblast-like mouse cell line (MDPC-23). (2) Methods: Metabolic activity was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test (MTT)assay, viability by the sulforhodamine B (SRB) assay, and the type of death and cell cycle analysis by flow cytometry. Alkaline phosphatase was evaluated by polymerase chain reaction (PCR), and dentin sialoprotein expression was assessed by immunocytochemistry. Mineralization was determined by the Alizarin Red S colorimetric assay and quantified by spectrophotometry. (3) Results: Life^® induced a decrease in metabolic activity and viability, which is associated with an increase cell death. WhiteProRoot^®MTA and Biodentine™ induced similar effects in cytotoxicity assays, with an increase in the expression of dentin sialoprotein (DSP) and formation of mineralized deposits, especially with Biodentine™. (4) Conclusions: The results of WhiteProRoot^®MTA confirm its indication for these therapies, justifying its recognition as the “gold standard”. Biodentine™ may be an alternative, since they promote the same cellular response that mineral trioxide aggregate (MTA) does.

Effect of grape seed extract (GSE) on functional activity and mineralization of OD-21 and MDPC-23 cell lines

Recent studies on functional tissue regeneration have focused on substances that favor cell proliferation and differentiation, including the bioactive phenolic compounds present in grape seed extract (GSE). The aim of this investigation was to evaluate the stimulatory potential of GSE in the functional activity of undifferentiated pulp cells and odontoblast-like cells. OD-21 and MDPC-23 cell lines were cultivated in odontogenic medium until subconfluence, seeded in 24-well culture plates in a concentration of 2x104/well and divided into: 1) OD-21 without GSE; 2) OD-21+10 µg/mL of GSE; 3) MDPC-23 without GSE; 4) MDPC-23+10 µg/mL of GSE. Cell proliferation, in situ detection of alkaline phosphatase (ALP) and total protein content were assessed after 3, 7 and 10 days, and mineralization was evaluated after 14 days. The data were analyzed by ANOVA statistical tests set at a 5% level of significance. Results revealed that cell proliferation increased after 10 days, and protein content, after 7 days of culture in MDPC-23 cells. In situ ALP staining intensity was higher in undifferentiated pulp cells and odontoblast-like cells after 7 and 10 days, respectively. A discrete increase in MDPC-23 mineralization after GSE treatment was observed despite OD-21 cells presenting a decrease in mineralized nodule deposits. Data suggest that GSE favors functional activity of differentiated cells more broadly than undifferentiated cells (OD-21). More studies with different concentrations of GSE must be conducted to confirm its benefits to cells regarding dentin regeneration.

Microwave-assisted synthesis and evaluation of type 1 collagen-apatite composites for dental tissue regeneration

The aim was to develop an economical and biocompatible collagen-based bioactive composite for tooth regeneration. Acid-soluble collagen was extracted and purified from fish scales. The design was innovated to molecularly tailor the surface charge sites of the nano-apatite providing chemical bonds with the collagen matrix via microwave irradiation technique. The obtained collagen was identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis. The composites were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis/differential scanning calorimetry, and scanning electron microscopy. MC3T3-E1 cell lines were used to assess the biological effects of these materials by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetra zolium bromide (MTT) assay. Indirect contact test was performed by extracting representative elutes in cell culture media and sulforhodamine B analysis was performed. Chorioallantoic membrane assay was conducted to define the new vessels formation behavior. The purity of collagen extracts was determined and showed two α-chains, i.e. the characteristic of type I collagen. Fourier transform infrared spectroscopy showed the characteristic peaks for amide I, I, III, and phosphate for collagen and composites. Scanning electron microscopy images showed three-dimensional mesh of collagen/apatite nano-fibers. Nontoxic behavior of composites was observed and there were graded and dose-related effects on experimental compounds. The angiogenesis and vessels formation behavior were observed in bioactive collagen composite. The obtained composites have potential to be used for tooth structure regeneration.

Direct Pulp Capping: What is the Most Effective Therapy?-Systematic Review and Meta-Analysis

INTRODUCTION

Direct pulp capping therapies use biomaterials to protect exposed tissues, inducing repair through the production of a mineralized barrier. The purpose of this study was to compare the effectiveness of biomaterials and techniques by means of a systematic review and meta-analysis.

METHODS

The PubMed, Cochrane, and Embase databases were used to search the literature published from January 1, 1980 until August 31, 2017. Studies that met inclusion criteria were screened by 2 authors individually. The meta-analysis was performed on mineral trioxide aggregate (MTA) cement vs calcium hydroxide cement, tricalcium silicate cement vs MTA cement, and adhesive systems vs CaOH cement and evaluated the success rate, inflammatory response, and dentin bridge formation.

RESULTS

Forty-six studies were included in the systematic review, while 22 studies were included in the meta-analysis. There was no significant heterogeneity between the studies. MTA cements showed a significantly higher success rate, in all parameters, compared with calcium hydroxide cements (odds ratio = 2.72; 95% confidence interval [CI] = 1.90-3.90; P = 0.000). However, when compared with the tricalcium silicate cements, there were no statistically significant differences (odds ratio = 1.18; 95% CI = 0.53-2.65; P = 0.672). Adhesive systems showed a significantly lower success rate, in all parameters, compared with calcium hydroxide cements (odds ratio = 0.062; 95% CI = 0.024-0.157; P = 0.000).

CONCLUSIONS

MTA cements have a higher success rate, with a lower inflammatory response and a more predictable hard dentin barrier formation than calcium hydroxide cements. However, there were no differences, in these parameters, when MTA cement was compared with tricalcium silicate cements. Dental adhesives systems showed the lowest success rates.

In vivo Outcomes of Indirect Pulp Treatment in Primary Posterior Teeth: 6 Months' Follow-up

Background:

Indirect pulp treatment (IPT) is a minimally invasive procedure based on the application of a protective liner on the affected dentin, thereby preserving the pulp vitality.

Aim:

This study aims to evaluate and compare the clinical and radiographic outcomes of IPT when a layer of calcium hydroxide (Dycal), mineral trioxide aggregate (MTA), or Biodentine was placed over the affected dentin in primary molars.

Materials and Methods:

A clinical trial with sample size of 45 primary molars between the age group of 4–9 years, of which 15 teeth were considered, each for Group I (Dycal), Group II (MTA), and Group III (Biodentine). Measurements on digitized radiographs were made at baseline, 3, and 6 months using Corel Draw software.

Results:

One-way ANOVA and post hoc tests indicated a statistically significant difference in dentin thickness (P < 0.05) in all the groups. Within Group I, the thickness of dentin was 0.066 ± 0.009 mm at 3 months and 0.099 ± 0.011 mm at 6 months. In Group II, 0.081 ± 0.010 mm at 3 months and 0.123 ± 0.016 mm at 6 months. In Group III, 0.102 ± 0.021 mm at 3 months and 0.154 ± 0.022 mm at 6 months.

Conclusions:

Clinically, 100% success rate was observed in all the groups whereas radiographically, Biodentine was superior to both the groups.