Cimentos a base de resina metacrilato associado ao fosfato de cálcio : propriedades biológicas

Este trabalho teve como objetivo avaliar as propriedades biológicas de cimentos experimentais a base de resina metacrilato contendo α-tricálcio fosfato (α-TCP) ou hidroxiapatita nanoparticulada (HAp) in vitro e in vivo. Para isto, os cimentos experimentais foram avaliados e comparados com AH Plus (AHP). Na etapa in vitro, os materiais foram mantidos em contato com meio de cultura por 24 horas, coletados e avaliados na concentração de 10%. Células-tronco da papila apical humana (SCAPs) foram submetidas aos ensaios de viabilidade brometo de 3-(4,5-dimetiltiazólio)-2,5-difenil tetrazólio (MTT) e sulfurodamina B (SRB) no período de 24 horas; e a bioatividade foi avaliada pela atividade da enzima fosfatase alcalina (ALP) e deposição de nódulos mineralizados pelo corante vermelho de Alizarina (AR), nos períodos de 1, 5, 10 e 15 dias. Na etapa in vivo, os materiais foram inseridos em tubos de polietileno e colocados no tecido subcutâneo de ratos para avaliação da reação inflamatória, sendo utilizado um tubo vazio como controle e avaliados os períodos de 7, 30 e 90 dias; para avaliação da deposição óssea, os cimentos α-TCP e AHP foram inseridos em cavidades confeccionadas no fêmur de ratos, sendo utilizada uma cavidade vazia como controle e avaliados os períodos de 30 e 90 dias. Para o ensaio de viabilidade e ensaios in vivo, foram utilizados os testes de Kruskal-Wallis e post hoc de Dunn; para avaliação da bioatividade in vitro foram utilizados os testes ANOVA e post hoc de Tukey (P 0,05) e o α-TCP apresentou menor resultado de viabilidade no teste MTT, sendo estatisticamente diferente dos outros (P 0.05), AHP apresentou menores valores em 5 dias (P 0.05), α-TCP, HAp e controle foram semelhantes aos 5 dias (P > 0.05), e em 10 e 15 dias, α-TCP apresentou os maiores valores, sendo diferente dos outros cimentos (P > 0.05). Na avaliação da resposta inflamatória in vivo, observou-se diminuição da inflamação e aumento de fibras colágenas em todos os grupos. Em 7 dias, α-TCP e HAp mostraram resultados semelhantes ao controle CT (P>0.05) e diferentes do AHP (P 0.05), diferindo do AHP (P 0.05), and α-TCP presented a lower viability result in MTT assay, being statistically different from the other sealers (P 0.05), AHP had the lowest values at 5 days (P 0.05), α-TCP, HAp and control were similar at 5 days (P > 0.05), and at 10 and 15 days, α-TCP presented the highest values, being different of the other sealers (P > 0.05). Regarding the evaluation of the inflammatory response in vivo, there was a decrease in inflammation and increase of collagen fibers in all groups. At 7 days, α-TCP and HAp showed similar results to the control (P > 0.05) and different from AHP (P 0.05), differing from the AHP (P < 0.05). It was concluded that the association of calcium phosphates and methacrylate resin showed good biocompatibility and bioactivity results in vitro and in vivo, presenting potential to be used as endodontic sealers in clinical practice

Centering and transportation: in vitro evaluation of continuous and reciprocating systems in curved root canals

One of the goals of endodontic therapy is the shaping and cleaning of the root canal system. In recent years, there has been multiple systems instrumentation, and changes in their dynamics are central to maintain the original shape of the canal after preparation. Aims: The aim of this study was to evaluate centering and transportation in curved root canals after using ProTaper® and MTwo® in continuous rotation, Reciproc® in reciprocating motion, and a step-down manual instrumentation technique. Settings and Design: Mesiobuccal roots of human extracted the first and second maxillary molars were selected and the canals (n = 60) were divided into four groups according to the preparation techniques: PT-ProTaper®; MT-MTwo®; RE-Reciproc®; MI-manual instrumentation. Subjects and Methods: The final apical diameter was standardized to a size 25. Centering and transportation were evaluated by cone-beam computed tomography and Adobe Photoshop 8.0 software. Statistical Analysis Used: The data were statistically analyzed by ANOVA and Tukey post hoc. Results: Results of transportation showed no statistical differences (P > 0.05) between groups, and significantly, difference (P < 0.05) between ProTaper® and Reciproc® was found when evaluating centering ability in the apical third. Conclusions: We concluded that there were no differences in transportation between the evaluated systems for the preparation of curved root canals with an apical instrumentation diameter of #25. For centering ability, in the apical third, ProTaper® presented worst behavior when compared to Reciproc®

Centering and transportation: in vitro evaluation of continuous and reciprocating systems in curved root canals

Context:One of the goals of endodontic therapy is the shaping and cleaning of the root canal system. In recent years, there has been multiple systems instrumentation, and changes in their dynamics are central to maintain the original shape of the canal after preparation. Aims: The aim of this study was to evaluate centering and transportation in curved root canals after using ProTaper® and MTwo® in continuous rotation, Reciproc® in reciprocating motion, and a step-down manual instrumentation technique. Settings and design: Mesiobuccal roots of human extracted the first and second maxillary molars were selected and the canals (n = 60) were divided into four groups according to the preparation techniques: PT-ProTaper®; MT-MTwo®; RE-Reciproc®; MI-manual instrumentation.Subjects and Methods: The final apical diameter was standardized to a size 25. Centering and transportation were evaluated by cone-beam computed tomography and Adobe Photoshop 8.0 software.Statistical Analysis Used: The data were statistically analyzed by ANOVA and Tukey post hoc. Results: Results of transportation showed no statistical differences (P > 0.05) between groups, and significantly, difference (P 0.05) between groups, and significantly, difference (P 0.05) between groups, and significantly, difference (P 0.05) between groups, and significantly, difference (P < 0.05) between ProTaper® and Reciproc® was found when evaluating centering ability in the apical third. Conclusions: We concluded that there were no differences in transportation between the evaluated systems for the preparation of curved root canals with an apical instrumentation diameter of #25. For centering ability, in the apical third, ProTaper® presented worst behavior when compared to Reciproc

Effect of calcium hypochlorite on the bond strength of the AH Plus sealer to dentin

Objetivo: avaliar o efeito do uso de hipoclorito de cálcio (Ca(OCl)2) como irrigante na resistência de adesão do cimento AH Plus (De Trey-Dentsply, Konstanz, Ale-manha) à dentina pelo teste de micro push-out. Mate-riais e método: trinta e três dentes humanos monorradi-culares foram seccionados transversalmente na junção amelocementária e divididos em três grupos: hipoclori-to de sódio (NaOCl) 2,5%, hipoclorito de cálcio 2,5% e soro fisiológico. Os canais foram preparados, irriga-dos ao final com EDTA 17% e obturados com cones de guta percha e cimento AH Plus. Após armazenagem por 7 dias, em 100% de umidade e a 37°C, os dentes foram seccionados transversalmente ao longo do eixo da raiz. Foram obtidas três fatias de cada dente (n=33), que foram submetidas ao ensaio de push-out. O tipo de falha foi analisado por fractografia e classificado em fa-lha adesiva, coesiva ou mista. Os valores de resistência de união foram analisados pelo teste de Kruskal-Wallis, com nível de significância de 95%. Resultados: o grupo Ca(OCl)2 2,5% apresentou a menor média de resistên-cia de adesão, diferindo estatisticamente do NaOCl e do soro fisiológico (p0,05). Conclusões: a falha predominante em todos os grupos foi a do tipo adesiva. O Ca(OCl)2 2,5% teve um efeito negativo sobre a força de adesão do AH Plus à dentina radicular quando comparado ao NaOCl 2,5%.Objective: to evaluate the effect of calcium hypochlo-rite (Ca(OCl)2) as an irrigant on the bond strength of the AH Plus sealer (De Trey-Dentsply, Konstanz, Germany) to dentin, using the micro push-out test. Materials and method: thirty-three single-rooted human teeth were cross-sectioned on the cementoenamel junction and di-vided into three groups: 2.5% sodium hypochlorite (Na-OCl), 2.5% calcium hypochlorite, and saline solution. The canals were prepared, irrigated with 17% EDTA at the end, and filled with gutta-percha cones and AH Plus sealer. After being stored for seven days at 100% humi-dity and 37ºC, the teeth were cross-sectioned along the root axis. Three slices of each tooth (n=33) were obtai-ned and subjected to the push-out test. Failure mode was analyzed by fractography and classified as adhe-sive, cohesive, or mixed. Bond strength values were analyzed by the Kruskall-Wallis test at 95% significan-ce level. Results: the 2.5% Ca(OCl)2 group showed the lowest bond strength mean, differing statistically from 2.5% NaOCl and saline solution (p0.05). Conclusion: the adhesive failure was predominant in all groups. The 2.5% Ca(OCl)2 had a negative effect on the bond strength of AH Plus to the root dentin when compared to 2.5% NaOCl

Radiopacity and cytotoxicity of Portland cement associated with niobium oxide micro and nanoparticles

Objective Mineral Trioxide Aggregate (MTA) is composed of Portland Cement (PC) and bismuth oxide (BO). Replacing BO for niobium oxide (NbO) microparticles (Nbµ) or nanoparticles (Nbη) may improve radiopacity and bioactivity. The aim of this study was to evaluate the radiopacity and cytotoxicity of the materials: 1) PC; 2) White MTA; 3) PC+30% Nbµ; 4) PC+30% Nbη. Material and Methods For the radiopacity test, specimens of the different materials were radiographed along an aluminum step-wedge. For cell culture assays, Saos-2 osteoblastic-cells (ATCC HTB-85) were used. Cell viability was evaluated through MTT assay, and bioactivity was assessed by alkaline phosphatase activity assay. Results The results demonstrated higher radiopacity for MTA, followed by Nbµ and Nbη, which had similar values. Cell culture analysis showed that PC and PC+NbO associations promoted greater cell viability than MTA. Conclusions It was concluded that the combination of PC+NbO is a potential alternative for composition of MTA

Cytotoxicity and Bioactivity of Calcium Silicate-based Cements in a Culture of Stem Cells from the Apical Papilla

Introduction: The present in vitro study evaluated the cytotoxicity and bioactivity of commonly-used calcium silicate-based cements in a culture of stem cells from the apical papilla (SCAPs). Materials and Methods: NeoMTA Plus (Avalon Biomed), BiodentineTM (Septodont) and MTA HP Repair (Angelus) cements were evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and sulphorhodamine-B (SRB) viability assays. Cells were seeded (1*104 cells mL-1) in 96-well plates and exposed to 1:4 diluted extract in 24 h and 72 h. For the analysis of bioactivity, alkaline phosphatase (ALP) enzyme activity and Alizarin Red S (AZR) were assessed after 24 h of cell culture in 12-well plates (1*104 cells mL-1), where cells were exposed to 1:4 diluted extract on days 1 and 7. Minimum Essential Eagle’s Medium alpha modification was used as control. ANOVA and Tukey’s post hoc test were used to compare the different cements at each experimental time point. Results: No significant differences were found between the cements and the control specimens on MTT at 24h and 72 h (P&gt;0.05); however, the calcium silicate-based cement materials showed higher cell viability compared to the control group (P&lt;0.05). In the 24-h SRB, NeoMTA Plus showed lower cell viability than BiodentineTM and MTA HP Repair (P&lt;0.05), with all groups similar to the control group (P&gt;0.05). Compared to 24-h results, only NeoMTA Plus presented increased cell viability at 72h (P&lt;0.05). ALP activity was similar across the materials at 1day (P&gt;0.05). ALP activity was higher for BiodentineTM when compared to NeoMTA Plus (P&lt;0.05), nevertheless, it was similar to MTA HP Repair and control groups (P&gt;0.05) at 7days. At 1- and 7-day periods ofAZR assay, BiodentineTM presented higher levels of mineralized nodule formation (P&lt;0.05). Conclusion: All evaluated calcium silicate-based cements demonstrated cell viability and bioactivity, suggesting that these (bio)materials may be indicated for use in regenerative dentine-pulp complex procedures

Biocompatibility and bioactivity of calcium silicate-based endodontic sealers in human dental pulp cells

Mineral Trioxide Aggregate (MTA) is a calcium silicate-based material. New sealers have been developed based on calcium silicate as MTA Fillapex and MTA Plus. Objective The aim of this study was to evaluate biocompatibility and bioactivity of these two calcium silicate-based sealers in culture of human dental pulp cells (hDPCs). Material and Methods The cells were isolated from third molars extracted from a 16-year-old patient. Pulp tissue was sectioned into fragments with approximately 1 mm3 and kept in supplemented medium to obtain hDPCs adherent cultures. Cell characterization assays were performed to prove the osteogenic potential. The evaluated materials were: MTA Plus (MTAP); MTA Fillapex (MTAF) and FillCanal (FC). Biocompatibility was evaluated with MTT and Neutral Red (NR) assays, after hDPCs exposure for 24 h to different dilutions of each sealer extract (1:2, 1:3 and 1:4). Unexposed cells were the positive control (CT). Bioactivity was assessed by alkaline phosphatase (ALP) enzymatic assay in cells exposed for one and three days to sealer extracts (1:4 dilution). All data were analyzed by ANOVA and Tukey post-test (p≤0.05%). Results MTT and NR results showed suitable cell viability rates for MTAP at all dilutions (90-135%). Cells exposed to MTAF and FC (1:2 and 1:4 dilutions) showed significant low viability rate when compared to CT in MTT. The NR results demonstrated cell viability for all materials tested. In MTAP group, the cells ALP activity was similar to CT in one and three days of exposure to the material. MTAF and FC groups demonstrated a decrease in ALP activity when compared to CT at both periods of cell exposure. Conclusions The hDPCs were suitable for the evaluation of new endodontic materials in vitro. MTAP may be considered a promising material for endodontic treatments

Influence of photobiomodulation therapy on root development of rat molars with open apex and pulp necrosis

This study aimed to evaluate the role of photobiomodulation (PBM) in apexification and apexogenesis of necrotic rat molars with an open apex. Rat molars were exposed to the oral environment for 3 weeks. Canals were rinsed with 2.5% NaOCl and 17% EDTA, filled with antibiotic paste and sealed. After 7 days, canals were rinsed and divided into six groups (n=6): mineral trioxide aggregate (MTA); blood clot (BC); human dental pulp stem cells (hDPSC); MTA+PBM; BC+PBM; and hDPSC+PBM. In hDPSC groups, a 1% agarose gel scaffold was used. Two groups were not exposed: healthy tooth+PBM (n = 6), healthy tooth (n = 3); and one was exposed throughout the experiment: necrotic tooth (n = 3). In PBM groups, irradiation was performed with aluminum gallium indium phosphide (InGaAlP) diode laser for 30 days within 24-h intervals. After that, the specimens were processed for histological and immunohistochemical analyses. Necrotic tooth showed greater neutrophil infiltrate (p < 0.05). Necrotic tooth, healthy tooth, and healthy tooth+PBM groups showed absence of a thin layer of fibrous condensation in the periapical area. All the other groups stimulated the formation of a thicker layer of fibers (p < 0.05). All groups formed more mineralized tissue than necrotic tooth (p < 0.05). PBM associated with MTA, BC, or hDPSC formed more mineralized tissue (p < 0.05). MTA+PBM induced apexification (p < 0.05). Rabbit polyclonal anti-bone sialoprotein (BSP) antibody confirmed the histological findings of mineralized tissue formation, and hDPSC groups exhibited higher percentage of BSP-positive cells. It can be concluded that PBM improved apexification and favored apexogenesis in necrotic rat molars with an open apex