Proposing new standards for testing solubility of pulp preservation materials.

OBJECTIVES: Quality control testing of dental materials requires a standard to enable the generation of reproducible and comparable data. Currently there are no standards for testing materials used for vital pulp therapy. The aim of this study was to develop a new standard to evaluate solubility of pulp preservation materials. METHODS: The solubility of three materials used for vital pulp therapy: Biodentine, TheraCal and Activa was evaluated using two international standards for dental materials ISO 4049:2019 (S1) and ISO 6876:2012 (S2). For both standards, a modified methodology was evaluated. This included changing the volume of the solution used (S1M, S2M), using Dulbecco's modified eagle medium (DMEM) as an alternative to water (S1D, S2D) and periodic solution change for the ISO 4049 method (S1P, S1MP). Materials were characterised before and after completion of solubility test using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. RESULTS: The test materials exhibited different solubility values depending on the methodology used. Biodentine exhibited significantly lower solubility when lower volumes of solution were used when tested using both ISO methods (p ≤ 0.05). TheraCal and Activa showed negative solubility values after desiccation when tested using ISO 4049:2019. The Biodentine exhibited changes in its microstructure which was dependent on the method used to test solubility. CONCLUSIONS: The solubility values obtained were dependent on the method used. It is thus important to use methods that replicate the clinical environment for meaningful evaluations.

Multifunctional Ca-Zn-Si-based micro-nano spheres with anti-infective, anti-inflammatory, and dentin regenerative properties for pulp capping application.

While pulp capping using a variety of materials has been applied clinically to preserve the health and vitality of the dental pulp and induce dentin repair no material meets all the anti-infection, anti-inflammation, and promoting pulp tissue regeneration criteria. Micro-nano materials of bioactive glasses (BG) with the biocompatibility and osteogenesis-promoting properties were developed for this study using Zn-doped bioactive glass (BGz) micro-nano spheres for dental pulp capping to control infection and inflammation and promote tissue regeneration. Of three key findings, the co-culture of Porphyromonas gingivalis showed that the BGz had an excellent antibacterial effect, and after being stimulated with BGz in vitro, macrophages showed a significant decrease of pro-inflammatory M1 markers compared with the undoped BG group. It is also noted that the conditioned medium derived from BGz-stimulated macrophages could significantly promote mineralized dentin formation of dental pulp cells (DPCs). In rats, acute pulp restoration experiments proved that BGz used as a pulp capping agent had excellent dentin regenerative properties. This work may provide a novel strategy to promote osteo/dentinogenic differentiation through regulating early inflammation, with potential applications in pulp capping.

Effect of preheating on cytotoxicity and physicochemical properties of light-cured calcium-based cements.

The aim of this study was to evaluate the degree of conversion, cytotoxicity, solubility and pH of photopolymerizable calciumbased cements submitted to preheating. The degree of conversion was analyzed by Fourier transform infrared, cytotoxicity by the MTT test and solubility through loss of mass. The data were subjected to statistical tests (ANOVA / Tukey's, p<0.05). The photopolymerizable materials showed a low degree of conversion, regardless of preheating. All materials caused a reduction in cell viability at 24 hours and 7 days, with the Dycal (control) being more cytotoxic. Heat had a positive effect on Biocal at 7 days. Dycal is the most soluble material. Heat had no effect on the solubility or pH of the polymerizable materials. It is concluded that photopolymerizable calcium-based cements have a low degree of conversion and are soluble, which results in mild to moderate cytotoxicity.

O objetivo do presente estudo foi avaliar o grau de conversão, citotoxicidade, solubilidade e pH de cimentos à base de cálcio fotopolimerizáveis submetidos a pré-aquecimento. O grau de conversão foi analisado por espectroscopia no infravermelho com transformada de Fourier, a citotoxicidade pelo teste de MTT e a solubilidade através da perda de massa. Os dados foram submetidos a testes estatísticos (ANOVA/Tukey, p<0,05). Os materiais fotopolimerizáveis apresentaram baixo grau de conversão, independente do pré-aquecimento. Todos os materiais causaram redução da viabilidade celular nas análises de 24 horas e 7 dias, sendo que o Dycal (controle) apresentouse mais citotóxico e o calor apresentou efeito positivo sobre o Biocal na análise de 7 dias. O Dycal é o material mais solúvel e o calor não causou efeito na solubilidade e pH dos materiais polimerizáveis. Assim, conclui-se que os cimentos à base de cálcio fotopolimerizáveis apresentam baixo grau de conversão e são solúveis, que resulta em citotoxicidade suave e moderada.

Effect of preheating on cytotoxicity and physicochemical properties of light-cured calcium-based cements / Efeito do pré-aquecimento na citotoxicidade e propriedades físico-químicas de cimentos à base de cálcio fotopolimerizáveis

ABSTRACT The aim of this study was to evaluate the degree of conversion, cytotoxicity, solubility and pH of photopolymerizable calciumbased cements submitted to preheating. The degree of conversion was analyzed by Fourier transform infrared, cytotoxicity by the MTT test and solubility through loss of mass. The data were subjected to statistical tests (ANOVA / Tukey's, p<0.05). The photopolymerizable materials showed a low degree of conversion, regardless of preheating. All materials caused a reduction in cell viability at 24 hours and 7 days, with the Dycal (control) being more cytotoxic. Heat had a positive effect on Biocal at 7 days. Dycal is the most soluble material. Heat had no effect on the solubility or pH of the polymerizable materials. It is concluded that photopolymerizable calcium-based cements have a low degree of conversion and are soluble, which results in mild to moderate cytotoxicity.

RESUMO O objetivo do presente estudo foi avaliar o grau de conversão, citotoxicidade, solubilidade e pH de cimentos à base de cálcio fotopolimerizáveis submetidos a pré-aquecimento. O grau de conversão foi analisado por espectroscopia no infravermelho com transformada de Fourier, a citotoxicidade pelo teste de MTT e a solubilidade através da perda de massa. Os dados foram submetidos a testes estatísticos (ANOVA/Tukey, p<0,05). Os materiais fotopolimerizáveis apresentaram baixo grau de conversão, independente do pré-aquecimento. Todos os materiais causaram redução da viabilidade celular nas análises de 24 horas e 7 dias, sendo que o Dycal (controle) apresentouse mais citotóxico e o calor apresentou efeito positivo sobre o Biocal na análise de 7 dias. O Dycal é o material mais solúvel e o calor não causou efeito na solubilidade e pH dos materiais polimerizáveis. Assim, conclui-se que os cimentos à base de cálcio fotopolimerizáveis apresentam baixo grau de conversão e são solúveis, que resulta em citotoxicidade suave e moderada.

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.

Development of self-adhesive pulp-capping agents containing a novel hydrophilic and highly polymerizable acrylamide monomer.

Several studies have shown the clinical success of hydraulic calcium-silicate cements (hCSCs) for direct and indirect pulp capping and root repair. However, hCSCs have various drawbacks, including long setting time, poor mechanical properties, low bond strength to dentin, and relatively poor handling characteristics. To overcome these limitations, a light-curable, resin-based hCSC (Theracal LC, Bisco) was commercially introduced; however, it did not exhibit much improvement in bond strength. We developed a light-curable self-adhesive pulp-capping material that contains the novel acrylamide monomer N,N'-{[(2-acrylamido-2-[(3-acrylamidopropoxy)methyl]propane-1,3-diyl)bis(oxy)]bis(propane-1,3-diyl)}diacrylamide (FAM-401) and the functional monomer 4-methacryloxyethyl trimellitate anhydride (4-MET). Two experimental resin-based hCSCs containing different calcium sources (portlandite: Exp_Pl; tricalcium silicate cement: Exp_TCS) were prepared, and the commercial hCSCs Theracal LC and resin-free hCSC Biodentine served as controls. The performance of each cement was evaluated based on parameters relevant for vital pulp therapy, such as curing degree on a wet surface, mechanical strength, as determined using a three-point bending test, shear bond strength to dentin, cytotoxicity, as determined using an MTT assay, and the amount of calcium released, as determined using inductively coupled plasma atomic emission spectrometry. Both experimental cements cured on wet surfaces and showed relatively low cytotoxicity. Furthermore, their flexural and shear bond strength to dentin were significantly higher than those of the commercial references. High calcium release was observed for both Exp_Pl and Biodentine. Thus, Exp_Pl as a new self-adhesive pulp-capping agent performed better than the commercial resin-based pulp-capping agent in terms of mechanical strength, bond strength, and calcium release.

The efficacy of different irrigation protocols in removing tricalcium silicate-based sealers from simulated root canal irregularities.

OBJECTIVE: The aim of this study was to evaluate the efficacy of different irrigation protocols in removing two tricalcium silicate-based sealers from simulated root canal irregularities and root canal walls. MATERIAL AND METHODS: Root canals of 140 single-rooted teeth were instrumented. In one-half of each root, an apical groove was created. The samples were divided into two main groups (n = 70) based on the sealer used. In group 1, the grooves were filled with MTA Fillapex; in group 2, BioRoot RCS. The reassembled root halves were divided into six experimental and one control groups: 2.5% NaOCl-17% EDTA (Passive ultrasonic irrigation [PUI]), 5% NaOCl/9% DualRinse HEDP (PUI), 2.5% NaOCl-7% Maleic acid (PUI), 2.5% NaOCl-17% EDTA (Er:YAG laser activated irrigation [LAI]), 2.5% NaOCl/9% DualRinse HEDP (LAI), 2.5% NaOCl-7% Maleic acid (LAI), Distilled water (Control). Specimens were scored using SEM. The data were analysed using Kruskal-Wallis and Mann Whitney U tests. RESULTS: Maleic acid and DualRinse HEDP removed higher amounts of MTA Fillapex from the grooves compared to EDTA, when used with both activation methods (p < .001). CONCLUSIONS: Ultrasonically activated maleic acid or DualRinse HEDP can be an effective irrigation regimen in removing tricalcium silicate-based sealers.

Comparison between calcium hydroxide mixtures and mineral trioxide aggregate in primary teeth pulpotomy: a randomized controlled trial.

OBJECTIVES: To evaluate the effect of calcium hydroxide (CH) associated with two different vehicles as a capping material for pulp tissue in primary molars, compared with mineral trioxide aggregate (MTA). METHODOLOGY: Forty-five primary mandibular molars with dental caries were treated by conventional pulpotomy using one of the following materials: MTA only (MTA group), CH with saline (CH+saline group) and CH with polyethylene glycol (CH+PEG group) (15 teeth/group). Clinical and periapical radiographic examinations of the pulpotomized teeth were performed 3, 6, and 12 months after treatment. Data were tested by chi-squared analysis and a multiple comparison post-test. RESULTS: The MTA group showed both clinical and radiographic treatment success in 14/14 teeth (100%), at all follow-up appointments. By clinical evaluation, no teeth in the CH+saline and CH+PEG groups had signs of mobility, fistula, swelling or inflammation of the surrounding gingival tissue. However, in the CH+saline group, radiographic analysis detected internal resorption in up to 9/15 teeth (67%), and inter-radicular bone resorption and furcation radiolucency in up to 5/15 teeth (36%), from 3 to 12 months of follow-up. In the CH+PEG group, 2/11 teeth (18%) had internal resorption and 1/11 teeth (9%) presented bone resorption and furcation radiolucency at all follow-up appointments. CONCLUSION: CH with PEG performed better than CH with saline as capping material for pulpotomy of primary teeth. However, both combinations yielded clinical and radiographic results inferior to those of MTA alone.

In vitro and in vivo effects of a novel bioactive glass-based cement used as a direct pulp capping agent.

Direct pulp capping is an important procedure for preserving pulp viability. The pulp capping agent must possess several properties, including usability, biocompatibility, and the ability to induce reparative dentin formation. In this study, a novel bioactive glass-based cement was examined to determine whether the cement has the necessary properties to act as a direct pulp capping agent. Physicochemical properties of the bioactive glass-based cement and in vitro effects of the cement on odontoblast-like cells, as well as in vivo effects on the exposed dental pulp, were analyzed. The cement immersed in water stabilized at pH10, and hydroxyapatite-like precipitation was induced on the surface of the cement in simulate body fluid. There were no cytotoxic effects on the viability, alkaline phosphatase activity, or calcium deposition ability of odontoblast-like cells. In the in vivo rat study of an exposed dental pulp model, the cement induced a sufficient level of reparative dentin formation by odontoblast-like cells expressing odontoblastic markers at the exposed area of the dental pulp. These results suggest that the newly developed bioactive glass-based cement provides favorable biocompatibility with the dental pulp and may be useful as a direct pulp capping agent. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 161-168, 2019.

Bone tissue reaction, setting time, solubility, and pH of root repair materials.

OBJECTIVES: This study aims to compare the bone tissue reaction, setting time, solubility, and pH of NeoMTA Plus, Biodentine (BD), and MTA Angelus (MTA-A). MATERIALS AND METHODS: Initial and final setting times (n = 7) and solubility up to 7 days (n = 11) were evaluated in accordance with ASTM C266-15 and ANSI/ADA Specification No. 57, respectively. pH (n = 10) was measured up to 28 days. Bone tissue reactions in 48 rats' femur were histologically analyzed after 7, 30, and 90 days. ANOVA and Tukey's tests compared setting time, solubility, and pH data; bone reactions data were compared by Kruskal-Wallis and Dunn's tests. RESULTS: NeoMTA Plus had longer initial and final setting times than MTA-A and BD (P < 0.05). At 7 days, BD showed the highest solubility, similar to NeoMTA Plus (P > 0.05) and different from MTA-A (P < 0.05). NeoMTA Plus had a progressive mass loss over time; at 7 days, it was significantly different from the initial mass (P < 0.05). BD showed higher pH in the periods assessed when compared to the other materials (P < 0.05). Bone tissue repair had no differences between groups in each experimental period (P > 0.05). All groups presented no difference from 30 to 90 days (P > 0.05) and had better bone repair at 90 days than at 7 days (P < 0.05). CONCLUSIONS: NeoMTA Plus, BD, and MTA-A showed satisfactory setting time, high mass loss, alkaline pH, and allowed bone repair. CLINICAL RELEVANCE: Calcium silicate-based cements are indicated for multiple clinical situations. NeoMTA Plus and BD showed satisfactory physical-chemical and biological properties, being considered as alternatives to MTA-A, as root repair materials for clinical use.

Comparison between calcium hydroxide mixtures and mineral trioxide aggregate in primary teeth pulpotomy: a randomized controlled trial

Abstract Objectives: To evaluate the effect of calcium hydroxide (CH) associated with two different vehicles as a capping material for pulp tissue in primary molars, compared with mineral trioxide aggregate (MTA). Methodology: Forty-five primary mandibular molars with dental caries were treated by conventional pulpotomy using one of the following materials: MTA only (MTA group), CH with saline (CH+saline group) and CH with polyethylene glycol (CH+PEG group) (15 teeth/group). Clinical and periapical radiographic examinations of the pulpotomized teeth were performed 3, 6, and 12 months after treatment. Data were tested by chi-squared analysis and a multiple comparison post-test. Results: The MTA group showed both clinical and radiographic treatment success in 14/14 teeth (100%), at all follow-up appointments. By clinical evaluation, no teeth in the CH+saline and CH+PEG groups had signs of mobility, fistula, swelling or inflammation of the surrounding gingival tissue. However, in the CH+saline group, radiographic analysis detected internal resorption in up to 9/15 teeth (67%), and inter-radicular bone resorption and furcation radiolucency in up to 5/15 teeth (36%), from 3 to 12 months of follow-up. In the CH+PEG group, 2/11 teeth (18%) had internal resorption and 1/11 teeth (9%) presented bone resorption and furcation radiolucency at all follow-up appointments. Conclusion: CH with PEG performed better than CH with saline as capping material for pulpotomy of primary teeth. However, both combinations yielded clinical and radiographic results inferior to those of MTA alone.

Cellular differentiation, bioactive and mechanical properties of experimental light-curing pulp protection materials.

OBJECTIVE: Materials for pulp protection should have therapeutic properties in order to stimulate remineralization and pulp reparative processes. The aim of this study was to evaluate the mechanical properties, biocompatibility, cell differentiation and bioactivity of experimental light-curable resin-based materials containing bioactive micro-fillers. METHODS: Four calcium-phosphosilicate micro-fillers were prepared and incorporated into a resin blend: 1) Bioglass 45S5 (BAG); 2) zinc-doped bioglass (BAG-Zn); 3) ßTCP-modified calcium silicate (ß-CS); 4) zinc-doped ß-CS (ß-CS-Zn). These experimental resins were tested for flexural strength (FS) and fracture toughness (FT) after 24h and 30-day storage in simulated body fluid (SBF). Cytotoxicity was evaluated using MTT assay, while bioactivity was evaluated using mineralization and gene expression assays (Runx-2 & ALP). RESULTS: The lowest FS and FT at 24h was attained with ß-CS resin, while all the other tested materials exhibited a decrease in FS after prolonged storage in SBF. ß-CS-Zn maintained a stable FT after 30-day SBF aging. Incorporation of bioactive micro-fillers had no negative effect on the biocompatibility of the experimental materials tested in this study. The inclusion of zinc-doped fillers significantly increased the cellular remineralization potential and expression of the osteogenic genes Runx2 and ALP (p<0.05). SIGNIFICANCE: The innovative materials tested in this study, in particular those containing ß-CS-Zn and BAG-Zn may promote cell differentiation and mineralization. Thus, these materials might represent suitable therapeutic pulp protection materials for minimally invasive and atraumatic restorative treatments.

Direct and Indirect Pulp Capping: A Brief History, Material Innovations, and Clinical Case Report.

Among the goals of pulp capping are to manage bacteria, arrest caries progression, stimulate pulp cells to form new dentin, and produce a durable seal that protects the pulp complex. This article will provide a general discussion of direct and indirect pulp capping procedures, offering practitioners a pragmatic and science-based clinical protocol for treatment of vital pulp exposures. A clinical case will be presented in which a novel light-cured resin-modified mineral trioxide aggregate hybrid material was used to manage a mechanical vital pulp exposure that occurred during deep caries excavation.

Biodentine™ material characteristics and clinical applications: a 3 year literature review and update.

INTRODUCTION: Biodentine™ has frequently been acknowledged in the literature as a promising material and serves as an important representative of tricalcium silicate based cements used in dentistry. AIM: To provide an update on the physical and biological properties of Biodentine™ and to compare these properties with those of other tricalcium silicate cements namely, different variants of mineral trioxide aggregate (MTA) such as ProRoot MTA, MTA Angelus, Micro Mega MTA (MM-MTA), Retro MTA, Ortho MTA, MTA Plus, GCMTA, MTA HP and calcium enriched mixture (CEM), Endosequence and Bioaggregate™. STUDY DESIGN: A comprehensive literature search for publications from November 20, 2013 to November 20, 2016 was performed by two independent reviewers on Medline (PubMed), Embase, Web of Science, CENTRAL (Cochrane), SIGLE, SciELO, Scopus, Lilacs and clinicaltrials.gov. Electronic and hand search was carried out to identify randomised control trials (RCTs), case control studies, case series, case reports, as well as in vitro and animal studies published in the English language. CONCLUSIONS: The enhanced physical and biologic properties of Biodentine™ could be attributed to the presence of finer particle size, use of zirconium oxide as radiopacifier, purity of tricalcium silicate, absence of dicalcium silicate, and the addition of calcium chloride and hydrosoluble polymer. Furthermore, as Biodentine™ overcomes the major drawbacks of MTA it has great potential to revolutionise the different treatment modalities in paediatric dentistry and endodontics especially after traumatic injuries. Nevertheless, high quality long-term clinical studies are required to facilitate definitive conclusions.

Physicochemical properties and cytotoxicity of an experimental resin-based pulp capping material containing the quaternary ammonium salt and Portland cement.

AIM: To evaluate in vitro the physicochemical properties, cytotoxicity and calcium phosphate nucleation of an experimental light-curable pulp capping material composed of a resin with antibacterial monomer (MAE-DB) and Portland cement (PC). METHODOLOGY: The experimental material was prepared by mixing PC with a resin containing MAE-DB at a 2 : 1 ratio. Cured pure resin containing MAE-DB served as control resin. ProRoot MTA and Dycal served as commercial controls. The depth of cure, degree of monomer conversion, water absorption and solubility of dry samples, calcium release, alkalinizing activity, calcium phosphate nucleation and the cytotoxicity of materials were evaluated. Statistical analysis was carried out using anova followed by Tukey's HSD test (equal variance assumed) or Tamhane test (equal variance not assumed) and independent-samples t-tests. RESULTS: The experimental material had a cure depth of 1.19 mm, and the mean degree of monomer conversion was 70.93% immediately post-cure and 88.75% at 24 h post-cure. The water absorption of the experimental material was between those of MTA and Dycal, and its solubility was significantly less (P < 0.05) than that of Dycal and higher than that of MTA. The experimental material exhibited continuous calcium release and an alkalinizing power between those of MTA and Dycal throughout the test period. Freshly set experimental material, control resin and all 24-h set materials had acceptable cytotoxicity. The experimental material, MTA and Dycal all exhibited the formation of apatite precipitates after immersion in phosphate-buffered saline. CONCLUSIONS: The experimental material possessed adequate physicochemical properties, low cytotoxicity and good calcium phosphate nucleation.

A theranostic dental pulp capping agent with improved MRI and CT contrast and biological properties.

Different materials have been used for vital dental pulp treatment. Preferably a pulp capping agent should show appropriate biological performance, excellent handling properties, and a good imaging contrast. These features can be delivered into a single material through the combination of therapeutic and diagnostic agents (i.e. theranostic). Calcium phosphate based composites (CPCs) are potentially ideal candidate for pulp treatment, although poor imaging contrast and poor dentino-inductive properties are limiting their clinical use. In this study, a theranostic dental pulp capping agent was developed. First, imaging properties of the CPC were improved by using a core-shell structured dual contrast agent (csDCA) consisting of superparamagnetic iron oxide (SPIO) and colloidal gold, as MRI and CT contrast agent respectively. Second, biological properties were implemented by using a dentinogenic factor (i.e. bone morphogenetic protein 2, BMP-2). The obtained CPC/csDCA/BMP-2 composite was tested in vivo, as direct pulp capping agent, in a male Habsi goat incisor model. Our outcomes showed no relevant alteration of the handling and mechanical properties (e.g. setting time, injectability, and compressive strength) by the incorporation of csDCA particles. In vivo results proved MRI contrast enhancement up to 7weeks. Incisors treated with BMP-2 showed improved tertiary dentin deposition as well as faster cement degradation as measured by µCT assessment. In conclusion, the presented theranostic agent matches the imaging and regenerative requirements for pulp capping applications. STATEMENT OF SIGNIFICANCE: In this study, we combined diagnostic and therapeutic agents in order to developed a theranostic pulp capping agent with enhanced MRI and CT contrast and improved dentin regeneration ability. In our study we cover all the steps from material preparation, mechanical and in vitro characterization, to in vivo study in a goat dental model. To the best of our knowledge, this is the first time that a theranostic pulp capping material have been developed and tested in an in vivo animal model. Our promising results in term of imaging contrast enhancement and of induction of new dentin formation, open a new scenario in the development of innovative dental materials.

Evaluation of chemical-physical properties and cytocompatibility of TheraCal LC.

TheraCal LC (TLC, Bisco Inc., Schaumburg, IL, USA) is a light-cured, resin-modified, calcium silicate-filled base/liner material designed for direct and indirect pulp-capping. In this study the result of the evaluation in vitro of the biocompatibility and chemical-physical properties of TLC are reported. TLC specimens were prepared under aseptic conditions in strict compliance with the manufacturer’s instructions and sterilized. Osteoblast-like cells (MG63) were used. For different time points, solubility, water uptake, alkalinizing activity and cytotoxicity were evaluated. In ddH20 and in DMEM+FBS, TLC showed a loss of material increasing simultaneously with the absorption capacity. The increase of water uptake of the material promoting the solubilization of mineral ions in medium is a requisite for a bioactive material. The alkalinizing activity is correlated to antimicrobial/bacteriostatic activity and to the ability to favor the formation of apatite deposits. The pH values for water absorption after immersion of the disks ranged between 8 and 9 at each times of evaluation. Cytotoxicity was not observed in MG63 cells treated with TLC and after 5 days, the cells were organized to form a confluent monolayer as demonstrated by fluorescence microscopy observation. TLC showed biocompatibility on MG63 cells allowing a physiologic cell growth and differentiation. The chemical-physical properties and biocompatibility of TLC observed in vitro in the present study, allows considering this cement as an innovative pulp-capping material for the vital pulp therapy.

Antimicrobial and biological activity of leachate from light curable pulp capping materials.

OBJECTIVES: Characterization of a number of pulp capping materials and assessment of the leachate for elemental composition, antimicrobial activity and cell proliferation and expression. METHODOLOGY: Three experimental light curable pulp-capping materials, Theracal and Biodentine were characterized by scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. The elemental composition of the leachate formed after 24h was assessed by inductively coupled plasma (ICP). The antimicrobial activity of the leachate was determined by the minimum inhibitory concentration (MIC) against multispecies suspensions of Streptococcus mutans ATCC 25175, Streptococcus gordonii ATCC 33478 and Streptococcus sobrinus ATCC 33399. Cell proliferation and cell metabolic function over the material leachate was assessed by an indirect contact test using 3-(4,5 dimethylthiazolyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. RESULTS: The hydration behavior of the test materials varied with Biodentine being the most reactive and releasing the highest amount of calcium ions in solution. All materials tested except the unfilled resin exhibited depletion of phosphate ions from the solution indicating interaction of the materials with the media. Regardless the different material characteristics, there was a similar antimicrobial activity and cellular activity. All the materials exhibited no antimicrobial activity and were initially cytotoxic with cell metabolic function improving after 3days. CONCLUSIONS: The development of light curable tricalcium silicate-based pulp capping materials is important to improve the bonding to the final resin restoration. Testing of both antimicrobial activity and biological behavior is critical for material development. The experimental light curable materials exhibited promising biological properties but require further development to enhance the antimicrobial characteristics.

Analysis of organic components in resin-modified pulp capping materials: critical considerations.

The purpose of this study was to elucidate the organic composition and eluates of three resin-based pulp-capping materials in relation to their indications and safety data sheets. Uncured samples of Theracal LC, Ultra-Blend Plus, and Calcimol LC were investigated using gas chromatography-mass spectrometry (GC-MS) and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). Identification/quantification of 7-d leachables of cured samples was performed using GC-MS for 2-hydroxyethyl methacrylate (HEMA), 2-(dimethylamino)ethyl methacrylate (DMAEMA), camphorquinone (CQ), ethylene glycol dimethacrylate (EGDMA), ethyl-4-(dimethylamino)benzoate (DMABEE), and triethylene glycol dimethacrylate (TEGDMA). A similar organic composition was found for Ultra-Blend and Calcimol; however, only Ultra-Blend is indicated for direct pulp-capping. In contrast to the other materials analysed, Theracal contained substances of high molecular weight. The safety data sheets of all materials were incomplete. We detected HEMA, CQ, and TEGDMA in eluates from Ultra-Blend and Calcimol, and it was considered that HEMA might have originated from decomposition of diurethane dimethacrylate (UDMA) in the GC-injector. For Theracal, additives associated with light curing (DMABEE and CQ) were detected in higher amounts (4.11 and 19.95 µg mm-2 ) than in the other materials. Pores were quantified in all samples by micro-computed tomography (micro-CT) analysis, which could influence leaching. The organic substances in the investigated materials might affect their clinical suitability as capping agents, especially for direct capping procedures.

Nanoscale chemical surface characterization of four different types of dental pulp-capping materials.

OBJECTIVES: The surface of any dental pulp-capping material has important implications for its clinical success because it is in direct contact with dental tissue, which influences its cytotoxicity. The aim was to determine the chemical composition of the first atomic layers of four pulp-protection agents because these atoms can initiate the pulp healing process. METHODS: Biodentine (Septodont), ProRoot MTA (Dentsply), Dycal (Caulk) and TheraCal (Bisco) were prepared (n=5) according to manufacturer recommendations. The chemical surface composition was analyzed using X-ray photoelectron spectroscopy (XPS), and the bulk composition was analyzed by Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX). Both survey and high resolution XPS spectra of the elements detected were obtained, with element-dependent probe depths of 4-5nm; the binding energy scale was normalized to the C1s adventitious carbon peak at 285eV. RESULTS: There was a significant difference between bulk and surface compositions for all the pulp-capping materials. The calcium surface concentrations at 0nm and 70nm were Dycal 7.9% and 15.1%; ProRoot MTA 14.1% and 17%; TheraCal 0% and 3.6%; and Biodentine 17.6% and 33.7%, respectively. Trace amounts of the following elements (<1%) were also found: Ti, S and Zr in Biodentine; Bi in ProRoot MTA and TheraCal; Na, P, Zn and N in Dycal. CONCLUSIONS: The XPS results showed that Ca in the surface layer could vary from 0 to 18%, depending on the material. Aliphatic carbons, from the polymerization reactions, especially in Dycal and TheraCal, were found to mask the other components. CLINICAL SIGNIFICANCE: This study compares, for the first time, the chemical composition of the first atomic layers of four pulp-capping materials. This information is relevant because the interaction between pulpar cells and the material's outermost atomic layer is an important factor for leading the pulpal response.