Systemic effect of mineral aggregate-based cements: histopathological analysis in rats.

OBJECTIVE: Several studies reported the local tissue reaction caused by mineral aggregate-based cements. However, few studies have investigated the systemic effects promoted by these cements on liver and kidney when directly applied to connective tissue. The purpose of this in vivo study was to investigate the systemic effect of mineral aggregate-based cements on the livers and kidneys of rats. MATERIAL AND METHODS: Samples of Mineral Trioxide Aggregate (MTA) and a calcium aluminate-based cement (EndoBinder) containing different radiopacifiers were implanted into the dorsum of 40 rats. After 7 and 30 d, samples of subcutaneous, liver and kidney tissues were submitted to histopathological analysis. A score (0-3) was used to grade the inflammatory reaction. Blood samples were collected to evaluate changes in hepatic and renal functions of animals. RESULTS: The moderate inflammatory reaction (2) observed for 7 d in the subcutaneous tissue decreased with time for all cements. The thickness of inflammatory capsules also presented a significant decrease with time (P<.05). Systemically, all cements caused adverse inflammatory reactions in the liver and kidney, being more evident for MTA, persisting until the end of the analysis. Liver functions increased significantly for MTA during 30 d (P<.05). CONCLUSION: The different cements induced to a locally limited inflammatory reaction. However, from the systemic point of view, the cements promoted significant inflammatory reactions in the liver and kidney. For MTA, the reactions were more accentuated.

Systemic effect of mineral aggregate-based cements: histopathological analysis in rats

Abstract Objective: Several studies reported the local tissue reaction caused by mineral aggregate-based cements. However, few studies have investigated the systemic effects promoted by these cements on liver and kidney when directly applied to connective tissue. The purpose of this in vivo study was to investigate the systemic effect of mineral aggregate-based cements on the livers and kidneys of rats. Material and Methods: Samples of Mineral Trioxide Aggregate (MTA) and a calcium aluminate-based cement (EndoBinder) containing different radiopacifiers were implanted into the dorsum of 40 rats. After 7 and 30 d, samples of subcutaneous, liver and kidney tissues were submitted to histopathological analysis. A score (0-3) was used to grade the inflammatory reaction. Blood samples were collected to evaluate changes in hepatic and renal functions of animals. Results: The moderate inflammatory reaction (2) observed for 7 d in the subcutaneous tissue decreased with time for all cements. The thickness of inflammatory capsules also presented a significant decrease with time (P<.05). Systemically, all cements caused adverse inflammatory reactions in the liver and kidney, being more evident for MTA, persisting until the end of the analysis. Liver functions increased significantly for MTA during 30 d (P<.05). Conclusion: The different cements induced to a locally limited inflammatory reaction. However, from the systemic point of view, the cements promoted significant inflammatory reactions in the liver and kidney. For MTA, the reactions were more accentuated.

Odontogenic differentiation potential of human dental pulp cells cultured on a calcium-aluminate enriched chitosan-collagen scaffold.

OBJECTIVE: The study aims to evaluate the odontogenic potential of human dental pulp cells (HDPCs) in contact with an experimental porous chitosan-collagen scaffold (CHC) enriched or not with a mineral phase of calcium-aluminate (CHC-CA). MATERIAL AND METHODS: To assess the chemotactic effect of the materials, we placed HDPCs seeded on transwell membranes in intimate contact with the CHC or CHC-CA surface, and the cell migration was monitored for 48 h. Additionally, cells were seeded onto the material surface, and the viability and proliferation were evaluated at several time points. To assess the odontoblastic differentiation, we evaluated ALP activity, DSPP/DMP-1 gene expression, and mineralized matrix deposition. HDPCs cultured onto a polystyrene surface (monolayer) were used as negative control group. RESULTS: The experimental CHC-CA scaffold induced intense migration of HDPCs through transwell membranes, with cells attaching to and spreading on the material surface after 24-h incubation. Also, the HDPCs seeded onto the CHC-CA scaffold were capable of migrating inside it, remaining viable and featuring a proliferative rate more rapid than that of CHC and control groups at 7 and 14 days of cell culture. At long-term culture, cells in the CHC-CA scaffold featured the highest deposition of mineralized matrix and expression of odontoblastic markers (ALP activity and DSPP/DMP-1 gene expression). CONCLUSIONS: According to the results, the CHC-CA scaffold is a bioactive and cytocompatible material capable of increasing the odontogenic potential of human pulp cells. Based on analysis of the positive data obtained in this study, one can suggest that the CHC-CA scaffold is an interesting future candidate for the treatment of exposed pulps. CLINICAL RELEVANCE: The experimental scaffold composed by a chitosan-collagen matrix mineralized with calcium aluminate seems to be an interesting candidate for in vivo application as a cell-free approach to dentin tissue engineering, which may open a new perspective for the treatment of exposed pulp tissue.

Cytotoxicity of New Calcium Aluminate Cement (EndoBinder) Containing Different Radiopacifiers.

This study aimed to evaluate the cytotoxicity of a calcium aluminate cement (EndoBinder) containing different radiopacifiers, Bi2O3, ZnO or ZrO2, compared with Mineral Trioxide Aggregate (MTA). According to ISO 10993-12:2012 (E) recommendations, 0.2 g of each cement were applied in transwell inserts and placed in 24-well culture plates containing 1 mL of culture medium (DMEM). After 24 h of incubation, the extracts (DMEM containing components released from the cements) were applied to immortalized odontoblast-like MDPC-23 cells. Cell viability (MTT test), alkaline phosphatase activity (ALP), total protein production and cell morphology (Scanning Electron Microscopy - SEM) were evaluated. The volume of 50 µL of extract was used to determine the chemical elements released by the cements using Energy Dispersive Spectroscopy (EDS). The following groups were established (n=6): NC - negative control (without treatment); EB - EndoBinder without radiopacifier; EBBO - EndoBinder+Bi2O3; EBZnO - EndoBinder+ZnO; EBZrO - EndoBinder+ZrO2 and WMTA - White MTA. Data were subjected to statistical analysis (Kruskal-Wallis test, level of significance=5%). Cells exposed to the different versions of EndoBinder presented small reduction in viability, total protein production and ALP activity, with values similar to the NC and WMTA groups (p>0.05). Different elements (C, O, Na, Al, P, Si, Cl, Bi, K) released by the cements were detected in the extracts. However, the cells had no significant changes in their morphology. EndoBinder and MTA did not affect negatively the metabolism of the odontoblastic-like cells, showing it to be cytocompatible, irrespective of the used radiopacifier.

Cytotoxicity of New Calcium Aluminate Cement (EndoBinder) Containing Different Radiopacifiers

Abstract This study aimed to evaluate the cytotoxicity of a calcium aluminate cement (EndoBinder) containing different radiopacifiers, Bi2O3, ZnO or ZrO2, compared with Mineral Trioxide Aggregate (MTA). According to ISO 10993-12:2012 (E) recommendations, 0.2 g of each cement were applied in transwell inserts and placed in 24-well culture plates containing 1 mL of culture medium (DMEM). After 24 h of incubation, the extracts (DMEM containing components released from the cements) were applied to immortalized odontoblast-like MDPC-23 cells. Cell viability (MTT test), alkaline phosphatase activity (ALP), total protein production and cell morphology (Scanning Electron Microscopy - SEM) were evaluated. The volume of 50 µL of extract was used to determine the chemical elements released by the cements using Energy Dispersive Spectroscopy (EDS). The following groups were established (n=6): NC - negative control (without treatment); EB - EndoBinder without radiopacifier; EBBO - EndoBinder+Bi2O3; EBZnO - EndoBinder+ZnO; EBZrO - EndoBinder+ZrO2 and WMTA - White MTA. Data were subjected to statistical analysis (Kruskal-Wallis test, level of significance=5%). Cells exposed to the different versions of EndoBinder presented small reduction in viability, total protein production and ALP activity, with values similar to the NC and WMTA groups (p>0.05). Different elements (C, O, Na, Al, P, Si, Cl, Bi, K) released by the cements were detected in the extracts. However, the cells had no significant changes in their morphology. EndoBinder and MTA did not affect negatively the metabolism of the odontoblastic-like cells, showing it to be cytocompatible, irrespective of the used radiopacifier.

Resumo Este estudo avaliou a citotoxicidade de um cimento de aluminato de cálcio (EndoBinder) contendo diferentes radiopacificadores, Bi2O3, ZnO ou ZrO2, comparativamente ao trióxido mineral agregado (MTA). Seguindo a norma ISO 10993-12:2012 (E), 0,2 g de cada cimento foi aplicada em insertos transwell, que foram colocados em placas de cultura de 24 wells contendo 1 mL de meio de cultura (DMEM). Após 24 h de incubação, os extratos (DMEM contendo componentes liberados dos cimentos) foram aplicados sobre células pulpares imortalizadas MDPC-23. Viabilidade celular (teste de MTT), atividade da fosfatase alcalina (ALP), produção de proteína total e a morfologia das células (Microscópio Eletrônico de Varredura - MEV) foram avaliadas. Um volume de 50 µL do extrato foi utilizado para determinar, através de Espectroscopia de Energia Dispersiva (EDS), os elementos químicos liberados pelos cimentos. Os seguintes grupos foram estabelecidos (n=6): NC - controle negativo (sem tratamento); EB - EndoBinder sem radiopacificador; EBBO - EndoBinder+Bi2O3; EBZnO - EndoBinder+ZnO; EBZrO - EndoBinder+ZrO2 e WMTA - MTA branco. Os dados foram submetidos à análise estatística (teste de Kruskal-Wallis, nível de significância=5%). Células expostas às diferentes versões de EndoBinder apresentaram pequena redução na viabilidade, produção de proteína total e atividade da ALP, com valores semelhantes aos grupos NC e WMTA (p>0,05). Diversos elementos (C, O, Na, Al, P, Si, Cl, Bi, K) liberados pelos cimentos foram detectados nos extratos. Entretanto, as células não apresentaram alterações significativas em sua morfologia. EndoBinder e MTA, não afetaram negativamente o metabolismo das células odontoblastóides, mostrando-se citocompatíveis, independente do radiopacificador utilizado.

Uninfiltrated Collagen in Hybrid Layers produced after Reduced Acid-etching Time on Primary and Permanent Dentin.

AIM: This study evaluated the influence of acid-etching time on collagen exposure in adhesive interfaces established on primary and permanent dentin. MATERIALS AND METHODS: Flat dentin surfaces were produced on sound primary molars and premolars (n = 8). The surfaces were divided into mesial and distal halves, and each half was etched with phosphoric acid for 5 or 15 seconds. The teeth were randomly allocated into two groups according to the adhesive system applied: Prime & Bond NT or Prime & Bond 2.1. After the adhesive application, the specimens were processed for Goldner's trichrome staining. The thickness of the uninfiltrated collagen zone (UCZ) in the hybrid layer was measured under optical microscopy. Data were analyzed by analysis of variance and Tukey tests (α = 0.05). RESULTS: The thickness of UCZ was adhesive dependent. Within the same substrate, the specimens treated with Prime & Bond 2.1 presented thicker UCZ when etched for 15 seconds. Collagen exposure was significantly higher for the primary teeth etched for 5 seconds and treated with Prime & Bond 2.1. CONCLUSION: The thickness of UCZ in hybrid layers is directly affected by acid-etching time and by the adhesive system applied. Primary dentin seems to be more susceptible to collagen exposure than is permanent dentin. CLINICAL SIGNIFICANCE: Both acid-etching time and adhesive system can influence the amount of exposed collagen interfering on resin-dentin bond quality, especially on primary dentin.

Efeito citotóxico de géis clareadores com diferentes concentrações de peróxido de hidrogênio aplicados diretamente sobre a dentina / Cytotoxic effects of a bleaching gel with different concentrations of hydrogen peroxide applied directly on dentin

Objetivo: Avaliar os efeitos citotóxicos de agentes clareadores com diferentes concentrações de PH sobre células odontoblastóides, quando aplicados diretamente sobre a superfície de dentina humana. Material e método: Cinquenta discos de dentina (0,5 mm de espessura) foram adaptados em câmaras pulpares artificiais (CPAs) e células MDPC-23 foram semeadas na superfície pulpar dos discos. Cinco grupos (n=10) foram estabelecidos: G1: 7,5% PH; G2: 20% PH; G3: 35% PH; G4: gel sem PH; G5: DMEN (controle). Os produtos foram aplicados na superfície oclusal dos discos por 2x de 15 minutos. A viabilidade (ensaio de MTT) e a morfologia celular (MEV) foram avaliadas imediatamente após o clareamento. Os dados de viabilidade celular foram submetidos ao teste de Kruskal-Wallis e Mann-Whitney (α=0,05). Resultados: Redução significante na viabilidade celular em relação ao controle (G5) foi observada para todas as concentrações de PH (p<0,05), associada a intensas alterações na morfologia celular. Entretanto, nenhuma diferença significante foi observada entre as três concentrações de PH. Também, não houve diferença estatística entre o grupo controle e o grupo gel sem PH (G5 e G4). Conclusão: Todas as concentrações de PH causaram efeitos citotóxicos de severos sobre as células MDPC-23, quando aplicados diretamente sobre a dentina. Entretanto, a intensidade do efeito tóxico não foi influenciada pela concentração de PH no agente clareador. Relevância clínica: Apesar das limitações deste estudo in vitro, os resultados indicam que o clareamento dental não deve ser realizado diretamente em áreas com exposição da dentina.

Objective: To evaluate the cytotoxic effects of bleaching gels with different concentrations of hydrogen peroxide (HP) on odontoblast-like cells, when applied directly on dentin. Material and method: Fifty dentin discs (0.5 mm thick) were adapted in artificial pulp chambers (APC) and MDPC-23 cells were seed on the pulpal side. The discs were divided into 5 groups (n=10): G1: HP 7.5%; G2: HP 20%; G3: HP 35%; G4: gel with no HP; and G5: no treatment (control). The gels were applied on the occlusal side of the discs for 2x of 15 min. Cellular viability (MTT assay) and morphology (SEM) were analyzed immediately after the bleaching procedure. Data of cellular viability were submitted to Kruskal-Wallis and Mann-Whitney tests (α=0.05). Results: Significant reduction in cellular viability was seen for all HP concentrations in comparison to the control (G5). However, no statistical significant difference was seen among the concentrations of HP. Likewise, there was no statistical difference between the control group (G5) and the group where the gel with no HP was applied (G4). Conclusion: All HP concentrations caused severe cytotoxic effects on the odontoblast-like cells when applied directly on dentin. However, the intensity of the cytotoxic effect was not influenced by the concentration of the HP included in the bleaching gel. Clinical significance: Within the limitations of this in vitro study, the results strongly indicate that dental bleaching procedures should not be performed directly on areas of dentin exposure.

Repair of Bone Defects Filled with New Calcium Aluminate Cement (EndoBinder).

INTRODUCTION: The aim of this study was to evaluate and compare the repair of bone defects filled with calcium aluminate cement (EndoBinder), mineral trioxide aggregate (MTA), and calcium hydroxide. METHODS: After mixing, the cements were inserted into bone defects (3.3 mm) mechanically created in the right and left tibias of 30 rats (Rattus norvegicus, Wistar). In the control group, the bone defects were filled with blood clot of the animal itself. After time intervals of 7, 30, and 90 days had elapsed, bone tissue biopsies (n = 5) were surgically obtained and submitted to laboratory processing. The response of bone tissue in contact with the materials was microscopically analyzed. The percentage of neoformed bone tissue in the defect was determined by means of planimetry counting points superimposed on the histologic image. RESULTS: Significant increase in the percentage of neoformed bone tissue was observed throughout the experimental periods in all groups (P < .05). For the cements EndoBinder and MTA (30 and 90 days), these percentage values were statistically higher than those of the control group (P < .05); however, they were similar to those of calcium hydroxide (P > .05). CONCLUSIONS: EndoBinder and MTA allowed complete repair of bone defects created in rat tibias.

Biocompatibility of new calcium aluminate cement: tissue reaction and expression of inflammatory mediators and cytokines.

INTRODUCTION: The aim of this study was to evaluate the biocompatibility of a new calcium aluminate cement (EndoBinder) in subcutaneous tissue of rats in comparison with mineral trioxide aggregate and calcium hydroxide hard-setting cement. METHODS: Polyethylene tubes (1.5 × 10 mm) containing the dental cements were implanted into dorsal subcutaneous tissue of 30 rats. After experimental periods of 7, 30, and 90 days, biopsies were performed for tissue response analysis under optical light microscope. The mRNA extraction was performed for molecular evaluation of the inflammatory process in the peri-implant tissue, which was submitted to quantitative real-time polymerase chain reaction analysis for inflammatory mediators and cytokines TNF-α, Ptges2, Il-1ß, Il-4, and Il-10. RESULTS: On the basis of the score used to grade the tissue reaction (0-3), EndoBinder (0) presented no inflammatory reaction after the 90-day period, a similar result to mineral trioxide aggregate and calcium hydroxide. The thickness of inflammatory capsules (µm) also presented significant decrease during the course of periods (P < .05). As regards expression of inflammatory mediators, Ptges2 and Il-10 were detected only at 7 and 30 days, with no statistically significant difference among the experimental groups (P > .05). CONCLUSIONS: EndoBinder induced limited inflammatory reaction. It was considered biocompatible when tested in subcutaneous tissue of rats.

Transdentinal cytotoxic effects of different concentrations of chlorhexidine gel applied on acid-conditioned dentin substrate.

It has been demonstrated that chlorhexidine digluconate (CHX) is capable of eliminating bacteria that may remain lodged in dentin after mechanical caries removal. In addition, the use of CHX on acid-etched dentin before adhesive system application delays the resin-dentin interface degradation, maintaining the integrity of the adhesive restorations. Despite these advantages of using CHX in restorative dentistry, when applied on dentin, this chemical agent may diffuse across dentinal tubules to cause toxic effects to the pulp cells. The aim of this study was to evaluate the transdentinal cytotoxic effects caused by different concentrations of CHX gels applied on acid-conditioned dentin substrate. Dentin discs (0.2-mm and 0.5-mm thick) were cut from human third molars and mounted in artificial pulp chambers. Odontoblast-like MDPC-23 cells (50,000 cells/cm(2)) were seeded on the pulpal side of the discs, and the carbon polymer gel (natrosol) with different CHX concentrations (0.12, 0.2, 1, and 2%), 35% phosphoric acid, or pure natrosol were applied on the occlusal side of the discs, forming six treatment groups (n = 10 discs/thickness). The dentin discs in the control group (n = 10 discs/thickness) did not receive any treatment. In each group, cell metabolism was analyzed by the methyltetrazolium assay (n = 8/thickness), and cell morphology was assessed by scanning electron microscopy (n = 2/thickness). Statistical analysis showed that CHX gels had a dose-dependent toxic effect on the odontoblast-like cells. Cell metabolism decreased by 12.8, 14.6, 18.3, 26, 13.7, and 10.5% for the 0.5-mm-thick dentin discs and 23, 26.3, 28.1, 34.5, 22.5, and 19.4% for the 0.2-mm-thick dentin discs treated with 0.12% CHX, 0.2% CHX, 1% CHX, 2% CHX, H(3)PO(4), and pure natrosol, respectively. According to the experimental conditions of the current investigation, it may be concluded that the application of natrosol gel with different concentrations of CHX on acid-conditioned dentin causes mild transdentinal cytotoxic effects to the MDPC-23 cells in a dose-dependent manner. Dentin acted as a biological barrier against CHX diffusion, and this effect was directly related to dentin thickness.

Efeitos citotóxicos e biocompatibilidade de agentes clareadotes usados na odontologia. Uma revisão de literatura / Cytotoxic effects and biocompatibility of bleaching agents used in dentistry. A literature review

O clareamento dental foi introduzido na Odontologia há mais de 150 anos. Todavia, apenas nas últimas décadas o clareamento de dentes vitais e não vitais passou a ser amplamente divulgado e extensamente aplicado na prática odontológica. Diferentes tipos de agentes clareadores, associados a técnicas específicas de aplicação, têm permitido a realização deste procedimento com relativo sucesso, até mesmo quando o tratamento é realizado pelos próprios pacientes (clareamento caseiro). Todavia, pesquisas in vivo e in vitro têm demonstrado que componentes ativos dos agentes clareadores, incluindo o peróxido de hidrogênio, tem a capacidade de difusão através das estruturas dentárias para alcançar o espaço pulpar. Esta difusão ocorre de maneira mais significante em dentes restaurados, através da infiltração dos agentes químicos pela interface dente/restauração, ou quando há exposição de dentina em casos de retração gengival, erosão, abfração e outros. Nesta situação, os efeitos citotóxicos dos agentes clareadores sobre células em cultura ou a irritação do tecido conjuntivo pulpar, associado ou não à sensibilidade pós-tratamento, estão diretamente relacionados com a quantidade de material que entra em contato com as células e/ou tecidos. Desta maneira, com o objetivo de prevenir danos ao complexo dentino-pulpar e sintomatologia dolorosa posterior, cuidados devem ser tomados na escolha do agente clareador e na sua técnica de aplicação, bem como na cuidadosa seleção dos pacientes que realmente necessitam do tratamento e que apresentam condições dentárias específicas para que se proceda o clareamento

About 150 years ago the tooth bleaching was introduced in dentistry. However, this procedure has been widely accepted and employed in the clinical practice only in the last decades. Different compositions of bleaching agent associated with specific techniques of application have allowed the successful bleaching of teeth even when performed by the patients at home. However, in vivo and in vitro studies have demonstrated that active chemical components of bleaching agents such hydrogen peroxide may diffuse across the tooth substrate (enamel and dentin) to reach the pulpal space. High diffusion rate of bleaching agent components may occurs particularly in restored dental cavities by leakage at the tooth/material interface, as well as in clinical situations in which the tubular dentin substrate is exposed to the oral environment. In these conditions, the cytotoxic effects of the bleaching agents associated or not with post-treatment sensitivity seem to be related with the amount of components that reach the connective tissue and their cells. Consequently, with the aim of preventing tissue damage and post treatment pain, the clinicians should take care concerning the choice of the adequate bleaching agent and its correct technique of application as well as to select patients that definitively need to be submitted to the treatment