Reparative Dentin Bridge Formation Research Articles

Experimental Pulp-Capping Agent Radiopaque Dicalcium Silicate Cement Facilitates Dentinogenesis

This study was designed to comparatively evaluate an experimental pulp-capping agent radiopaque dicalcium silicate cement (RDSC), white-colored mineral trioxide aggregate (WMTA), iRoot BP Plus and Biodentine both ex vivo and in vivo. Fourier Transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were utilized to analyze the phase composition of pulp-capping agents. The surface morphology and element analysis were finished by Scanning electron microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDX). Color stability of the cements and pulp responses induced by different cements were examined by ex-vivo human tooth culture model and in-vivo miniature pig model. Micro-computed tomography was used for quantitative evaluation of the newly formed mineralized tissue. RDSC exhibited discoloration in both models, while WMTA exhibited more visible discoloration. The occurrence of discoloration for WMTA was significantly higher than that of RDSC (p < 0.05), iRoot BP Plus and Biodentine on the 7th day, also higher (p < 0.05) than that of iRoot BP Plus and Biodentine on the 70th day. Mineralized foci were noted in all 7-days groups except the control group both ex vivo and in vivo. Intact and complete reparative dentin bridge formation which possessed tubular structures was noted in all 70-days groups in vivo. RDSC appeared to induce the thickest dentin bridge formation among all these pulp-capping agents which showed statistically significant difference to that of Biodentine (p < 0.05). With decent biological properties, RDSC may have the potential to be a pulp-capping agent recommended in the non-aesthetic area alternative to WMTA, Biodentine and iRoot BP Plus.

Evaluation of Reparative Dentine Bridge Formation after Direct Pulp Capping with Biodentine.

ABSTRACTAim:To evaluate the capability of Biodentine for direct pulp capping in permanent teeth.Materials and Methods:The pulp of 11 human intact premolars were mechanically exposed in standard cavity dimensions and then capped with Biodentine for direct pulp capping. After 9–12 weeks, all teeth were extracted. All teeth were scanned using intraoral radiograph or cone-beam computed tomography (CBCT) scan before, right after pulp capping therapy, and after 9–12 weeks on both patient real and extracted teeth for evaluation of reparative dentin bridge formation. All clinical symptoms and signs were also recorded. Data were collected and analyzed using the MedCal statistical software at the significance of 0.05.Results:There was reparative dentin bridge formation in all experimental teeth, on both patient real and extracted teeth.Conclusions:The Biodentine could induce the formation of reparative dentin in direct pulp capping. The CBCT scan was the reliable modality for evaluation of dentin bridge formation.

Cytotoxicity and Bioactivity of Dental Pulp-Capping Agents towards Human Tooth-Pulp Cells: A Systematic Review of In-Vitro Studies and Meta-Analysis of Randomized and Controlled Clinical Trials.

Background. In the era of biology-driven endodontics, vital pulp therapies are regaining popularity as a valid clinical option to postpone root-canal treatment. In this sense, many different materials are available in the market for pulp-capping purposes. Objectives. The main aim of this systematic review and meta-analysis was to examine literature regarding cytotoxicity and bioactivity of pulp-capping agents by exposure of human dental pulp cells of primary origin to these materials. A secondary objective was to evaluate the inflammatory reaction and reparative dentin-bridge formation induced by the different pulp-capping agents on human pulp tissue. Data sources. A literature search strategy was carried out on PubMed, EMBASE and the Web of Science databases. The last search was done on 1 May 2020. No filters or language restrictions were initially applied. Two researchers independently selected the studies and extracted the data. Study selection included eligibility criteria, participants and interventions, study appraisal and synthesis methods. In vitro studies were included when human dental pulp cells of primary origin were (in) directly exposed to pulp-capping agents. Parallel or split-mouth randomized or controlled clinical trials (RCT or CCT) were selected to investigate the effects of different pulp-capping agents on the inflammation and reparative bridge-formation capacity of human pulp tissue. Data were synthesized via odds ratios (95% confidence interval) with fixed or random effects models, depending on the homogeneity of the studies. The relative risks (95% confidence interval) were presented for the sake of interpretation. Results. In total, 26 in vitro and 30 in vivo studies were included in the systematic review and meta-analysis, respectively. The qualitative analysis of in vitro data suggested that resin-free hydraulic calcium-silicate cements promote cell viability and bioactivity towards human dental pulp cells better than resin-based calcium-silicate cements, glass ionomers and calcium-hydroxide cements. The meta-analysis of the in vivo studies indicated that calcium-hydroxide powder/saline promotes reparative bridge formation better than the popular commercial resin-free calcium-silicate cement Pro-Root MTA (Dentsply-Sirona), although the difference was borderline non-significant (p = 0.06), and better than calcium-hydroxide cements (p < 0.0001). Moreover, resin-free pulp-capping agents fostered the formation of a complete reparative bridge better than resin-based materials (p < 0.001). On the other hand, no difference was found among the different materials tested regarding the inflammatory effect provoked at human pulp tissue. Conclusions. Calcium-hydroxide (CH) powder and Pro-Root MTA (Dentsply-Sirona) have shown excellent biocompatibility in vitro and in vivo when tested on human cells and teeth. Their use after many years of research and clinical experience seems safe and proven for vital pulp therapy in healthy individuals, given that an aseptic environment (rubber dam isolation) is provided. Although in vitro evidence suggests that most modern hydraulic calcium-silicate cements promote bioactivity when exposed to human dental pulp cells, care should be taken when these new materials are clinically applied in patients, as small changes in their composition might have big consequences on their clinical efficacy. Key findings (clinical significance). Pure calcium-hydroxide powder/saline and the commercial resin-free hydraulic calcium-silicate cement Pro-Root MTA (Dentsply-Sirona) are the best options to provide a complete reparative bridge upon vital pulp therapy. Systematic review registration number. PROSPERO registration number: CRD42020164374.

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

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

Mineralization-inducing potentials of calcium silicate-based pulp capping materials in human dental pulp cells.

BackgroundThis study was performed to provide a long-term bacterial seal through the formation of reparative dentin bridge, calcium silicate-based pulp capping materials have been used at sites of pulpal exposure. The aim of this study was to evaluate the mineralization-inducing potentials of calcium silicate-based pulp capping materials (ProRoot MTA [PR], Biodentine [BD], and TheraCal LC [TC]) in human dental pulp cells (HDPCs).MethodsSpecimens of test materials were placed in deionized water for various incubation times to measure the pH variation and the concentration of calcium released. The morphology of HDPCs cultured on the specimens was examined using a confocal laser scanning microscope (CLSM). Alizarin red S staining and alkaline phosphatase assays were used to evaluate mineralization-inducing potentials of the capping materials.ResultsBD showed the highest calcium release in all test periods, followed by PR and TC. (p<0.05). All experimental groups showed high alkalinity after 1 day, except at 14 days. BD showed the highest cell viability compared with PR and TC after 1 and 3 days, while TC showed the lowest value (p<0.05). The CLSM analysis showed that cells were well adhered and expressed actin filaments for all pulp capping materials. Mineralization by PR and BD groups was higher than that by TC group based on alizarin red S staining. BD showed significantly higher alkaline phosphatase activity than PR and TC, while TC showed the lowest value (p<0.05).ConclusionWithin the limitations of the in vitro study, BD had higher mineralization-inducing potential than PR and TC.

Tomographic Evaluation of Reparative Dentin Formation after Direct Pulp Capping with Ca(OH)2, MTA, Biodentine, and Dentin Bonding System in Human Teeth

IntroductionNew materials can increase the efficiency of pulp capping through the formation of a complete reparative dentin bridge with no toxic effects. The present study involved tomographic evaluations of reparative dentin bridge formation after direct pulp capping with calcium hydroxide, mineral trioxide aggregate (MTA), Biodentine (Septodont, Saint Maur des Fossés, France), and Single Bond Universal (3M ESPE, Seefeld, Germany) in human teeth. MethodsForty-four caries-free, intact, human third molars scheduled for extraction were subjected to mechanical pulp exposure and assigned to 1 of 4 experimental groups depending on the pulp capping agent used: calcium hydroxide, MTA, Biodentine, or Single Bond Universal. After 6 weeks, the teeth were extracted and processed for cone-beam computed tomographic imaging and histologic examination. Tomographic data, including the density and volume of formed reparative dentin bridges, were evaluated using a scoring system. ResultsThe reparative dentin formed in the calcium hydroxide, MTA, and Biodentine groups was significantly superior to that formed in the Single Bond Universal group in terms of thickness and volume. The dentin bridges in the Biodentine group showed the highest average and maximum volumes. The mean density of dentin bridges was the highest in the MTA group and the lowest in the Single Bond Universal group. ConclusionsThe volume of reparative dentin bridges formed after direct pulp capping is dependent on the material used. Biodentine and MTA resulted in the formation of bridges with a significantly higher average volume compared with Single Bond Universal, and cone-beam computed tomographic imaging allowed for the identification of the location of dentin bridges.

Evaluation of a Bioceramic as a Pulp Capping Agent In Vitro and In Vivo

IntroductionThis study aims to investigate the effects of the bioceramic iRoot BP Plus (Innovative Bioceramix Inc, Vancouver, Canada) as a pulp capping agent in vitro and in vivo. MethodsIn vitro, human dental pulp cells (hDPCs) were seeded into plates with the prepared iRoot BP Plus or mineral trioxide aggregate (MTA) packed in the bottom of different wells. The proliferation of hDPCs was determined using the 3,(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. Meanwhile, 2 animal models of direct pulp capping and pulpotomy were applied in Wistar rats in vivo. The exposed pulps were capped with iRoot BP Plus or MTA. After 1 and 4 weeks, maxillary segments were obtained and prepared for histologic analysis. ResultshDPCs grew very well even in the place contacted with MTA or iRoot BP plus in vitro. MTA and iRoot BP Plus both enhanced the proliferation of hDPCs (P < .05). In vivo, results revealed that few inflammatory cells were present in the pulpal area corresponding to the pulp exposure. A slight layer of newly generated matrix was also observed next to MTA and iRoot BP Plus after 1 week. A complete reparative dentin bridge with polarizing odontoblastlike cells was detected in all specimens in the iRoot BP Plus group after 4 weeks. ConclusionsiRoot BP Plus exhibited good biocompatibility to pulp tissue and induced the proliferation of dental pulp cells and the formation of reparative dentin bridge. iRoot BP plus may be used as a pulp capping material for vital pulp therapy

Pulp preservation in immature permanent teeth

New treatment strategies for direct pulp capping and pulpotomy have shown promising potentials for improved outcomes in immature teeth with extensive caries, traumatic pulp exposures, or anatomical anomalies. Preservation and protection of the dental pulp in developing teeth promote root maturation and extend tooth survivability by postponing or even preventing more complex endodontic and restorative care. Early intervention using hydraulic calcium silicate cements such as mineral trioxide aggregate (MTA) stimulates pulpal cell recruitment and differentiation, up‐regulates transformation factors (gene expression), and promotes dentinogenesis. Calcium hydroxide, resin‐modified glass ionomer cements, hydrophilic resins, and formocresol have been shown to be less effective as bioactive agents when used in vital pulp therapy. Improved treatment procedures for pulp preservation include the use of caries detector dye to preserve the remineralizable inner carious layer and the use of sodium hypochlorite as a hemostatic and diagnostic agent to differentiate reversible from irreversible pulpitis. Although stepwise excavation and the use of calcium hydroxide is still being advocated, pulp capping and pulpotomy procedures using calcium silicate‐based cements are becoming widely accepted as more effective procedures. MTA and new hydraulic calcium silicate cements provide biocompatible environments that predictably promote reparative dentin bridge formation when placed under properly bonded and sealed composite restorations. Hydraulic calcium silicate cements appear to provide a promising future for the preservation of pulpal integrity in immature teeth when used with modified and conservative treatment protocols.

Histological evaluation of odontoblast-like cells response after capping application of calcium hydroxide and hydroxilapatite in dog’s pulp

This study was conducted to observe the response of dog's dental pulp to hydrpxylapatite (Hap) and calcium hydroxide when used as pulp capping materials. After the pulps of 22 teeth were exposed, they were capped with either Hap or calcium hydroxide. Histological analysis was performed 8 weeks after treatment. Results showed that pulp exposure caused irreversible injury of odontoblasts, which were subsequently replaced by similar, odontoblast-like cells. These cells were able for reparative dentin bridge formation in 6 cases treated with calcium hydroxide and almost all the cases treated with hydroxylapatite. The presence of odontoblast-like cells seemed to be crucial for reparative dentinogenesis. The capping material was of less importance. In conclusion neither calcium hydroxide nor hydrxylapatite had completely satisfied all the requirements of an ideal capping material, although Hap can be recognized as a superior alternative to calcium hydroxide.

Systemic evaluation of various haemostatic agents following local application prior to direct pulp capping

Limited physiological information is available regarding the role of hemostatic agents to control the success of direct pulp capping treatment in order to help save vital pulps from pulpotomy, pulpectomy or extraction. The aim of this study was to test whether placement of various hemostatic agents would alter short-term pulp healing following direct pulp capping. Class V cavity preparations with pulp exposures were prepared in 31-nonhuman primate teeth, pulp hemorrhage was controlled by placement of epinephrine, Consepsis®, sodium hypochlorite or combinations of these agents. Each exposure was then direct capped with composite resin and then observed immediately or after 13, and 28-days. Histological examination of pulp healing was conducted according to ISO standards for pulp inflammation, soft tissue organization, reactionary and reparative dentin bridge formation. Physiological measurement of heart rate and blood pressure were continuously recorded during the three operative procedures. Local pulp treatment with the various hemostatic agents did not alter systemic blood pressure or heart rate during local pulp application. All hemostatic treatments provided acceptable biocompatibility. Minor differences in pulp healing were observed, but there were no statistically significant differences between treatments (Pe”0.05). We conclude that hemostatic treatment had little effect on systemic pulp physiology or healing.

Pulpal reactions to two experimental bonding systems for pulp capping procedures.

This study evaluated the pulpal responses induced by application of two types of bonding system to the exposed dental pulp. One consisted of the following steps: etching with neutralized EDTA, application of an experimental water-based photocuring bonding agent, and restoration with a commercially available photocuring resin composite (EDTA etching system). The other was treatment with an experimental water-based self-etching primer, application of a commercially available bonding agent, and restoration with a commercially available photocuring resin composite (self-etching system). These two systems of treatment were applied to the exposed pulp. Calcium hydroxide was used as a control for the direct pulp-capping material. The pulps in class V cavities in the anterior teeth of beagles were mechanically exposed and then filled using the etching, the self-etching, or the Ca(OH)2 system. The beagles were sacrificed on the 7th, 30th or 90th postoperative day, and pulpal responses were investigated histopathologically using light microscopy. The EDTA etching system induced severe pulp reactions at 7 days after the operation. These reactions did not completely diminish after 90 days. Reparative dentin formation was observed at day 90. The self-etching system showed moderate pulp reactions, which gradually decreased over the experimental period. Reparative dentin bridge formation was observed at day 90. No necrosis of the pulp was observed at any time. Calcium hydroxide induced both moderate and severe initial pulp reactions, with reparative dentin formation evident at day 30. Necrosis was observed in the superficial pulp. It is suggested that the EDTA etching agent caused not only pulpal damage but also re-bleeding because of rinsing and drying. The self-etching system is a promising system for direct pulp capping.

Effects of various calcium phosphate biomaterials on reparative dentin bridge formation

This article reports on various calcium phosphate materials placed directly on the dental pulp of pig primary teeth. The following capping agents were tested, using light microscopy and microradiography of undecalcified sections: tricalcium phosphate plus magnesium, 50% tricalcium phosphate-50% hydroxylapatite, and octocalcium phosphate, with calcium hydroxide being used as a reference material. The results show that tricalcium phosphate plus magnesium and octocalcium phosphate induce formation of a dystrophic dentin similar to that of dentinogenesis imperfecta or even vasodentin. Compared with calcium hydroxide, the 50% tricalcium phosphate plus 50% hydroxylapatite compound provides the best dentinogenetic effects, resulting in a thicker reparative dentin bridge and quicker formation of normal tubular dentin.