Clinical Comparison of Eggshell Derived Calcium Hydroxyapatite with Dycal® as Indirect Pulp Capping Agents in Primary Molars

Abstract Objective: To evaluate and compare the efficacy of eggshell derived calcium hydroxyapatite with Dycal® as indirect pulp capping material in primary molars. Material and Methods: A total of 32 carious primary molars from 22 children (6-10-years) were screened, of which 26 primary molars meeting inclusion criteria were selected and equally divided into two groups. At the first appointment, the infected dentin was excavated using a spoon excavator after treating the carious part with Carie-Care™ chemomechanical caries removal agent. After this, eggshell derived calcium hydroxyapatite in Group 1 and Dycal® in Group 2 were used as liners followed by restoration of the cavity with type IX glass ionomer cement. Clinical assessment for pain and radiographic assessment for measurement of the amount of reparative dentin thickness formation was performed at baseline, 8 weeks and 3 months. The data were subjected to statistical analysis by one-way ANOVA and Kruskal-Wallis tests. Results: Higher mean reparative dentin formation was found in eggshell derived calcium hydroxyapatite group than Dycal® group at the end of 8 weeks and 3 months and the difference was significant statistically (p<0.001). Conclusion: Eggshell derived calcium hydroxyapatite seems to be a suitable alternative to Dycal® (calcium hydroxide) that can be used as a liner for indirect pulp capping in primary molars.

Sinus floor elevation using a new bovine bone grafting material: case report and bone grafting materials update / Actualización en materiales de relleno óseo: reporte de un caso clínico de elevamiento del piso del seno maxilar usando un nuevo material de relleno óseo bovino

Bone grafting is important to preserve the alveolar bone ridge height and volume for dental implant placement. Even though implant-supported overdentures present highly successful outcomes, it seems that a great number of edentulous individuals have not pursued implant-based rehabilitation. The cost of the treatment is one of the reasons of discrepancy between highly successful therapy and its acceptance. Therefore, the development of biomaterials for bone grafting with comparable characteristics and biological effects than those renowned internationally, is necessary. In addition, domestic manufacture would reduce the high costs in public health arising from the application of these biomaterials in the dental feld. The purpose of this clinical case report is to provide preliminary clinical evidence of the efficacy of a new bovine bone graft in the bone healing process when used for sinus floor elevation. (AU)

El uso de injertos óseos es importante para preservar la altura y el volumen de la cresta alveolar para la colocación de implantes dentales. Si bien las sobredentaduras implanto-soportadas presentan resultados altamente exitosos, la mayoría de las personas desdentadas no han sido rehabilitadas mediante implantes dentales. Uno de los principales motivos por los cuales los pacientes no aceptan este tipo de tratamiento, altamente exitoso, es el elevado costo del mismo. Por ello, es necesario el desarrollo de biomateriales de injerto óseo con características y efectos biológicos comparables a los reconocidos internacionalmente. Asimismo, la fabricación nacional reduciría los altos costos en Salud Pública derivados de la aplicación de estos biomateriales en el campo dental. El objetivo de esta comunicación es presentar un caso clínico a fin de proporcionar evidencia preliminar acerca de la eficacia de un nuevo injerto de hueso bovino en el proceso de cicatrización ósea en el levantamiento del piso del seno maxilar. (AU)

Análise de citotoxicidade, desmineralização e potencial clareador de géis clareadores experimentais, baseado em peróxido de carbamida 15% adicionados de nano-hidróxiapatita / Analysis of cytotoxicity, demineralization and bleaching potential of experimental bleaching gels, based on 15% carbamide peroxide added with nanohydroxyapatite

O clareamento dental é considerado um procedimento muito seguro, de efeito rápido e agradável, tornando-se um dos procedimentos mais realizados na odontologia. Contudo, o mesmo apresenta alguns efeitos colaterais, sendo o principal deles a sensibilidade dental, que pode ser causada pela citotoxidade, pela desmineralização, pela geração de espécies reativas do oxigênio na polpa dental e pela degradação da região interprismática facilitando o estimulo nos túbulos dentinários. Diante disso, a presente pesquisa avaliou a desmineralização, a citotoxidade e o potencial clareador de géis clareadores experimentais baseados em peróxido de carbamida (PC) 15%, adicionados de 5% e 10% de nano partículas de hidroxiapatita (n-Hap). Para a avaliação cromática foram utilizados 36 incisivos bovinos divididos em 3 grupos: Grupo1 PC 15%, Grupo 2 PC 15% adicionado 5% nHap e grupo 3 PC 15% com 10% n-Hap, mensurando a cor antes e depois do procedimento terapêutico clareador com auxilio de um espectrofotômetro. As coordenadas do CIELAB foram analisadas para verificação da diferença de cor (ΔE) obtida entre os grupos e dentro do próprio grupo (L*) e, após a analise estatística, foi verificado que todos os géis foram capazes de clarear e não houve diferenças entre os grupos. A citotoxidade foi verificada através da absorbância das células viáveis após o tratamento com o MTT e 1:800 das preparações de agente clareador e gel contendo 5% e 10% de n-Hap aplicadas sobre células L929. Nesse caso os grupos foram desiguais estatisticamente, apresentando o PC 15% como o mais tóxico, seguido do PC 15% adicionado de 10% de n-Hap e o melhor resultado foi obtido pelo gel acrecido de 5% de n-Hap. A análise do conteúdo mineral foi realizada pela fluorescência de raios X por dispersão de energia, onde foi necessário o uso de 15 dentes bovinos, que tiveram seus terços médios seccionados, embutidos em resina epóxi e planificados, e foram dividos em grupos de 5 CPs. Cada CP foi aferido em 8 pontos diferentes antes e depois, nos mesmos pontos da terapia clareadora. Foi então verificado que os géis experimentais apresentaram menor perda de Ca e P. No entanto, não houve diferenças estatísticas entre os grupos 2 e 3. Diante das limitações do presente estudo in vitro é possível concluir que os géis experimentais contendo n-Hap foram eficazes em reduzir a citotoxidade e desmineralização sem perder a eficácia da terapia clareadora

Dental whitening is considered a very safe, quick and pleasant procedure, making it one of the most accomplished procedures in dentistry. However, it has some side effects, the main one being sensibility, which can be caused by cytotoxicity, demineralization, oxygen arrival in the dental pulp and the degradation of the interprismatic region facilitating the stimulation in the dentin tubes. Therefore, the present study evaluated the demineralization, cytotoxicity and bleaching potential of 15% carbamide peroxide-based (PC) based bleaching gels added with 5% and 10% nano-hydroxyapatite (n-Hap) particles. For the chromatic evaluation, 36 bovine incisors were divided into 3 groups: Group 1 PC 15%, Group 2 PC 15% added 5% nHap and group 3 PC 15% with 10% n-Hap, measuring the color before and after the the CIELAB coordinates were analyzed to verify the color difference (Δe) obtained between the groups and within the group (L *). After the statistical analysis it was verified that all the gels were able to lighten and there were no differences between the groups. Cytotoxicity was verified by optical density of viable cells after treatment with MTT and 1: 800 of the bleach and gel preparations containing 5% and 10% nHap applied in L929 cells. In this case, the groups were statistically unequal, presenting 15% PC as the most toxic, followed by PC 15% added with 10% n-Hap and the best result was obtained by the 5% n-Hap increased gel. The mineral content analysis was performed by X-ray Fluorescence by energy dispersion, where it was necessary to use 15 bovine teeth, which had their middle sections sectioned, embedded in epoxy resin and planned, and were divided into groups of 5 CPs, each CP was measured at 8 different points before and after, at the same points of the bleaching therapy, then it was verified that the experimental gels presented a lower loss of Ca and P, however there were no statistical differences between groups 2 and 3. On the face of the limitations of the present in vitro study, it is possible to conclude that the experimental gels were effective in reducing the cytotoxicity and demineralization without losing the effectiveness of the bleaching therapy.

A comparison of different bone graft materials in peri-implant guided bone regeneration

Abstract The aim of this study was to compare the effects of hydroxyapatite (HA), deproteinized bovine bone (DPB), human-derived allogenic bone (HALG), and calcium sulfate (CAP) graft biomaterials used with titanium barriers for bone augmentation to treat peri-implant defects in rat calvarium treated by guided bone regeneration (GBR). Thirty-two female Sprague-Dawley rats were divided into four groups: DPB, HALG, HA, and CAP. One titanium barrier was fixed to each rat's calvarium after the titanium implants had been fixed. In total, 32 titanium implants and barriers were used. Ninety days after the surgical procedure, all the barriers were removed. After decalcification of bone tissue, the titanium implants were removed gently, and new bone regeneration in the peri-implant area was analyzed histologically. Immunohistochemical staining of vascular endothelial growth factor (VEGF) was also performed. There were no statistically significant between-group differences in new bone regeneration or VEGF expression after 3 months. According to the results of the histological and immunohistochemical analyses, none of the grafts used in this study showed superiority with respect to new bone formation.

Behavior study of the doped castor bean polymer rod with bioactive glass and hidroxyapatite in mice femur medullary canal

Abstract Purpose To evaluate the polymer doped rods behavior with bioactive glass and hydroxyapatite for possible application as a fracture fixing method. Methods Twenty eight Rattus norvegicus Wistar underwent bone defect for access to the femoral medullary canal and distributed into three experimental groups: group A - doped castor bean polymer with bioactive glass; group B - castor bean polymer and; group C - castor bean polymer doped with bioactive glass and hydroxyapatite. After 15 and 60 evaluation days, the femurs were removed and sent for histology and scanning electron microscopy. Results Initially mild and moderate inflammatory infiltrate is observed that decreases as time goes by, and the presence of connective tissue capsule around the graft in all groups. Regarding the biomaterials resorption little was observed. The implanted rods did not favor the osteoconductive process in the femoral medullary canal which was observed only in the C15 group. Conclusions The association of castor bean polymer, bioactive glass and hydroxyapatite was biocompatible and osteointegrable. The osteoconductive only occurred in the presence of hydroxyapatite and bioactive glass (C15 Group) and little biodegradation was observed.

Biocompósitos eletrofiados de PLLA com alto conteúdo de partículas de fosfatos de cálcio funcionalizados para regeneração óssea / Electrospun PLLA biocomposites with high content of calcium phosphates functionalized for bone regeneration

Este trabalho visou a produção de suportes para crescimento celular constituídos de compósitos de poli(L-lactídeo) (PLLA) e diversos tipos de fosfatos de cálcio (CaP). A hidroxiapatita deficiente em cálcio (HAD) e o fosfato octacálcico (OCP) em tamanhos submicrométricos foram sintetizados. Hidroxiapatita (HA) e o ß-fosfato tricálcico (ß-TCP) foram adquiridos da Sigma-Aldrich. Uma mistura de HAD:ß-TCP (7:3) também foi preparada. Para melhorar a dispersão da fase mineral em uma matriz polimérica de PLLA, utilizou-se cloreto de lauroíla para funcionalizar a superfície dos CaP. Os espectros de infravermelho e a análise termogravimétrica confirmaram a presença de laurato na superfície de partículas de CaP. As partículas de HA pura também foram funcionalizadas com cloreto de lauroíla para fins comparativos. Compósitos de PLLA/CaP-laurato foram fabricados utilizando a técnica de eletrofiação. A funcionalização da superfície do CaP com laurato resultou em uma melhoria significativa na dispersão de partículas de CaP na matriz polimérica, permitindo a inclusão de até 40% da fase mineral sem comprometer as propriedades mecânicas. Microscopia eletrônica de varredura (SEM) e microscopia eletrônica de transmissão (TEM) foram utilizadas para investigar a morfologia da fibra. A perda de massa e a liberação de cálcio dos suportes durante a degradação em uma solução salina tamponada com fosfato (PBS) foram medidas. HAD e OCP se mostraram ser mais solúveis do que HA e HAD:ß-TCP (7:3). A bioatividade dos compósitos foi investigada por imersão das fibras em um fluido corporal simulado (SBF) a 37 °C e pH 7.4. Embora todos os suportes de PLLA/CaP-laurato foram capazes de formar uma camada de apatita em sua superfície após a exposição em SBF, os resultados demonstraram um aumento significativo na mineralização quando HAD, OCP e HAD:ß-TCP (7:3) são a fase mineral no compósito em vez da HA. Além disso, malhas produzidas a partir das fibras eletrofiadas de PLLA/CaP-laurato, utilizadas como suporte para crescimento celular, favoreceram a adesão e proliferação de células de fibroblastos de camundongo (NIH-3T3) e células tronco mesenquimais de dentes decíduos humanos (SHED). Finalmente, suportes a partir das malhas PLLA/HAD-laurato e PLLA/OCP-laurato apresentaram melhor desempenho para acelerar a calcificação in vitro como resultado da osteoindução de células SHED e de células pré-osteoblásticas derivadas de calvária de rato (MC3T3-E1) se comparados aqueles contendo HA e HAD:ß-TCP (7:3). Esses novos materiais são propostos como biocompósitos de rápida degradação de CaP, para serem utilizados em aplicações de regeneração óssea em ortodontia e ortopedia

This work aimed at the generation of scaffolds for cellular growth constituted by poly(L-lactide) (PLLA) and several types of calcium phosphate (CaP). Calcium deficient hydroxyapatite (HAD) and octacalcium phosphate (OCP) were synthesized in submicrometer sizes. Hydroxyapatite (HA) and ß-tricalcium phosphate (ß-TCP) were purchased from Sigma-Aldrich. A mixture of HAD:ß-TCP (7:3) also was prepared. In order to improve the dispersion of the mineral phase in a PLLA polymeric matrix, lauroyl chloride was used to functionalize the surface of CaP. Infrared spectra and thermal gravimetric analysis confirmed the presence of laurate on the surface of CaP particles. Neat HA particles were also functionalized with lauryl chloride for comparative purposes. Composites of PLLA/CaP-laurate were fabricated by electrospinning method. The functionalization of CaP surfaces resulted in significant improvement of the dispersion of CaP particles into the polymeric matrix, allowing inclusion of up to 40% of mineral phase without compromising its mechanical properties. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to investigate the morphology of the fibers. The mass loss and calcium release of the scaffolds during degradation in phosphate buffered saline (PBS) were measured. HAD and OCP are more soluble than HA and HAD:ß-TCP (7:3). The bioactivity of the composites was investigated by immersing the fibers in a simulated body fluid (SBF) at 37°C and pH 7.4. Although all PLLA/CaP-laurate can form apatite precipitation on their surface after exposition to SBF, the results demonstrate a significant enhancement in the mineralization when HAD, OCP and HAD:ß-TCP (7:3) are the mineral phase in the composite instead of HA. Furthermore, mats obtained from PLLA/CaP-laurate electrospun fibers favored the mouse fibroblast cells (NIH-3T3) and stem cells from human exfoliated deciduous teeth (SHED) attachment and proliferation. Finally, PLLA/HAD-laurate and PLLA/OCP-laurate meshes showed better performance in accelerate the calcium phosphate mineralization on its surface as a result of the in vitro osteoinduction of SHEDs and calvaria derived mouse preosteoblastic cells (MC3T3-E1) if compared of those containing HA and HAD:ß-TCP (7:3). These new materials are proposed as fast degradation CaP biocomposites to be used in bone regeneration applications in orthodontics and orthopedics

Effects of a buried magnetic field on cranial bone reconstruction in rats

ABSTRACT The understanding of bone repair phenomena is a fundamental part of dentistry and maxillofacial surgery. Objective The present study aimed to evaluate the influence of buried magnetic field stimulation on bone repair in rat calvaria after reconstruction with autogenous bone grafts, synthetic powdered hydroxyapatite, or allogeneic cartilage grafts, with or without exposure to magnetic stimulation. Material and Methods Ninety male Wistar rats were divided into 18 groups of five animals each. Critical bone defects were created in the rats’ calvaria and immediately reconstructed with autogenous bone, powdered synthetic hydroxyapatite or allogeneic cartilage. Magnetic implants were also placed in half the animals. Rats were euthanized for analysis at 15, 30, and 60 postoperative days. Histomorphometric analyses of the quantity of bone repair were performed at all times. Results These analyses showed significant group by postoperative time interactions (p=0.008). Among the rats subjected to autogenous bone reconstruction, those exposed to magnetic stimulation had higher bone fill percentages than those without magnetic implants. Results also showed that the quality of bone repair remained higher in the former group as compared to the latter at 60 postoperative days. Conclusions After 60 postoperative days, bone repair was greater in the group treated with autogenous bone grafts and exposed to a magnetic field, and bone repair was most pronounced in animals treated with autogenous bone grafts, followed by those treated with powdered synthetic hydroxyapatite and allogeneic cartilage grafts.

Avaliação in vitro de enxaguatórios experimentais com compostos bioativos na prevenção/remineralização de lesões de mancha branca ativa durante tratamento ortodôntico / In vitro evaluation rinses experiments with bioactive compounds in the remineralization of white spot lesions during orthodontic treatment

O objetivo deste estudo foi avaliar in vitro por meio da Fluorescência de Raios X por Dispersão de Energia (XRF) e Microscopia Eletrônica de Varredura (MEV) o efeito remineralizante de enxaguatórios bucais com compostos bioativos, sendo nanopartículas de hidroxiapatita de cálcio (nanoHAp) associadas ou não a fluoreto, fluoreto de sódio e saliva no esmalte dental bovino. Foram utilizados 15 corpos de prova (CP) a partir de 15 incisivos bovinos que foram divididos aleatoriamente em 3 grupos, com 5 CP cada um. Após colagem dos braquetes, as amostras foram submetidas a um alto desafio de cárie com solução desmineralizante de cloreto de cálcio 2,2 mM, fosfato de sódio monohidratado 2,2 mM e ácido acético 0,05 M, com pH ajustado entre 4,4 e 5,2, permanecendo durante 48 horas em solução desmineralizante, em temperatura ambiente, simulando lesão de mancha branca ativa no esmalte dental bovino ao redor desses braquetes ortodônticos. Em seguida, cada grupo foi denominado conforme os respectivos tratamentos a serem utilizados. Grupo 1 (G1) solução de fluoreto de sódio (0,05%); Grupo 2 (G2) solução aquosa de nanopartículas de hidroxiapatita de cálcio (0,75%) e Grupo 3 (G3) solução aquosa de fluoreto de sódio (0,05%) associada a nanopartículas de hidroxiapatita de cálcio (0,75%). Foram obtidos os valores de XRF e imagens em MEV antes e depois da desmineralização e antes e depois do tratamento. Os dados obtidos foram submetidos à análise estatística pelo teste ANOVA para comparação entre as médias iniciais e finais de cada grupo e para comparação dos grupos de tratamentos distintos com nível de significância de 5% (p ≤ 0,05). Nas leituras por XRF, nenhum dos enxaguatórios testados foram eficientes na remineralização das lesões de mancha branca no período de 5 dias. E nas imagens de MEV, o grupo que recebeu tratamento com a solução de NanoHAp 0,75% (G2) apresentou deposição mineral uniforme na superfície de esmalte desmineralizado, vedando os prismas de esmalte.

The aim of the present study was to assess in vitro, through energy dispersive X-ray fluorescence (XRF) and Scanning Electron Microscopy (SEM), the remineralizing effect of mouth rinses with bioactive compounds, which are calcium hydroxyapatite nanoparticles (nanoHAp) associated or not with fluoride, sodium fluoride and saliva in bovine dental enamel. Fifteen specimens from 15 bovine incisors were used and randomly distributed into three groups, with 5 specimens each. After bonding the brackets, the specimens were subjected to a high caries challenge with 2.2 mM calcium chloride, 2.2 mM sodium phosphatemonohydrate and 0.05 mM acetic acid demineralizing solution, pH adjustedbetween 4.4 to 5.2, kept in demineralizing solution for 48 hours, at room temperature, simulating active white spot lesion on bovine dental enamel around those orthodontic brackets. Then, each group was named according torespective treatments to be used: Group 1 (G1) ­ 0.05% sodium fluoride solution; Group 2 (G2) ­ aqueous solution of 0.75% calcium hydroxyapatite nanoparticles; and Group 3 (G3) ­ aqueous solution of 0.05% sodium fluoride associated with 0.75% calcium hydroxyapatite nanoparticles. The XRF values were obtained and the SEM images were taken before and after the demineralization, and before and after the treatment. Data were submitted to statistical analysis by ANOVA test to compare the initial and final means of each group and to compare the distinct treatment groups with a significance level at 5% (p ≤ 0,05). In the XRF readings, none of the tested mouth rises were efficient in the remineralization of white spot lesions in the period of 5 days. In the SEM images, the group treated with 0.75% NanoHAp solution (G2) showed uniform mineral deposition of the demineralized enamel surface, sealing theenamel prisms

El tamaño de partículas de injertos óseos en senos maxilares, tiene efectos diferenciales sobre la estabilidad? / Does the particle size of bone grafts in maxillary sinuses have differential effects on the stabilitiy of implants?

La elevación del piso del seno maxilar or medio de injertos óseos es un procedimiento predecible y frecuente para el tratamiento del reborde alveolar superior atrófico. El mateiççrial de injerto debe poseer propiedades mecánicas y biológicas que promuevan la osteoconducción y una buena estabilidad de los implantes colocados en dicho injerto. Objetivo: evaluar el efecto del tamaño de las partículas (pequeñas 0,25-1 mm o grandes 1-2 mm) de hidroxiapatita natural macroporosa de origen bovino, usadas en procedimientos de relleno de seno maxilar humano, sobre el coeficiente de estabilidad de los implantes (ISQ) que se coloquen en el injerto, obtenidos a través de análisis de frecuencia de resonancia. Material y método: se midió el coeficiente de estabilidad de 30 implantes colocados en 15 pacientes (8 varones y 7 mujeres), tratados con procedimientos de relleno de seno maxilar, usando como material de injerto hidroxiapatita natural macroporosa de origen bovino (Bio-Oss), de partículas grandes o de partículas pequeñas (11 y 7 respectivamente). Las mediciones se realizaron en el momento de la cirugía de colocación de los implantes a través de análisis de frecuencia de resonancia. El período de cicatrización de las elevaciones de seno maxilar fue de 8 a 9 meses. Los datos fueron analizados con estadística no paramétrica. Resultados: no se detectaron diferencias significativas en los varones de ISQ de los implantes colocados en senos rellenados con partículas pequeñas og randes (P<0,05). Los valores de desvío estándar de RFA fueron numéricamente mayores en partículas grandes (+- 13,46 ISQ) que en las pequeñas (+- 5,23 ISQ). Conclusión: dentro de las limitaciones de este estudio realizado en senos maxilares humanos, se concluye que el diferente tamaño de las partículas de hidroxiapatita natural macroporosa de origen bovino, no tiene un efecto diferencial en los valores de ISQ de los implantes dentales colocados en los senos tratados...

An animal experimental study of porous magnesium scaffold degradation and osteogenesis

Our objective was to observe the biodegradable and osteogenic properties of magnesium scaffolding under in vivo conditions. Twelve 6-month-old male New Zealand white rabbits were randomly divided into two groups. The chosen operation site was the femoral condyle on the right side. The experimental group was implanted with porous magnesium scaffolds, while the control group was implanted with hydroxyapatite scaffolds. X-ray and blood tests, which included serum magnesium, alanine aminotransferase (ALT), creatinine (CREA), and blood urea nitrogen (BUN) were performed serially at 1, 2, and 3 weeks, and 1, 2, and 3 months. All rabbits were killed 3 months postoperatively, and the heart, kidney, spleen, and liver were analyzed with hematoxylin and eosin (HE) staining. The bone samples were subjected to microcomputed tomography scanning (micro-CT) and hard tissue biopsy. SPSS 13.0 (USA) was used for data analysis, and values of P<0.05 were considered to be significant. Bubbles appeared in the X-ray of the experimental group after 2 weeks, whereas there was no gas in the control group. There were no statistical differences for the serum magnesium concentrations, ALT, BUN, and CREA between the two groups (P>0.05). All HE-stained slices were normal, which suggested good biocompatibility of the scaffold. Micro-CT showed that magnesium scaffolds degraded mainly from the outside to inside, and new bone was ingrown following the degradation of magnesium scaffolds. The hydroxyapatite scaffold was not degraded and had fewer osteoblasts scattered on its surface. There was a significant difference in the new bone formation and scaffold bioabsorption between the two groups (9.29±1.27 vs 1.40±0.49 and 7.80±0.50 vs 0.00±0.00 mm3, respectively; P<0.05). The magnesium scaffold performed well in degradation and osteogenesis, and is a promising material for orthopedics.

Determinación de la bioactividad de capas de alginato de sodio en discos de hidroxiapatita / Determination of bioactivity in sodium alginate layers of hydroxyapatite disks

OBJETIVO: el propósito central de este trabajo es evaluar la bioactividad in vitro de capas de alginato de sodio en discos de hidroxiapatita. MÉTODOS: los discos de hidroxiapatita fueron elaborados mediante procesos sucesivos de prensado y de sinterizado en un horno eléctrico. Las capas de alginato de sodio se obtuvieron empleando el método de sobrepresión y una disolución acuosa de alginato de sodio al 5 %. En el ensayo de bioactividad las muestras a estudiar fueron sumergidas en fluido biológico simulado. La caracterización de las muestras se realizó empleando microscopia electrónica de barrido y energía dispersiva de rayos X. RESULTADOS: en las muestras de hidroxiapatita sometidas al ensayo de bioactividad, con y sin capas de alginato de sodio, se observó la formación de precipitados ricos en calcio y fósforo. Además, se determinó que con el aumento del tiempo de inmersión en el fluido biológico simulado se incrementan las dimensiones de los aglomerados formados por partículas apatíticas. CONCLUSIONES: los resultados experimentales corroboran que la hidroxiapatita es bioactiva y demuestran que las capas estudiadas de alginato de sodio en discos de hidroxiapatita poseen un comportamiento bioactivo.

OBJECTIVE: the main purpose of the study is to evaluate in vitro bioactivity in sodium alginate layers of hydroxyapatite disks. METHODS: the hydroxyapatite disks were manufactured by successive pressing and sintering in an electric furnace. The sodium alginate layers were obtained by overpressure and a 5% sodium alginate aqueous solution. For the bioactivity assay, the study samples were soaked in simulated biological fluid. Characterization of the samples was conducted by scanning electron microscopy and energy dispersive X rays. RESULTS: the bioactivity assay of hydroxyapatite samples with and without sodium alginate layers revealed the formation of precipitates rich in calcium and phosphorus. It was also found that an increase in the time of immersion in the simulated biological fluid brought about an increase in the size of agglomerates of apatite particles. CONCLUSIONS: experimental results show that hydroxyapatite is indeed bioactive, and that the sodium alginate layers of hydroxyapatite disks which were studied behave bioactively.

Efeito do conteúdo de titânia e da alteração da superfície por meio da aplicação do recobrimento biomimético nas propriedades mecânicas do compósito Y-TZP/TiO2 / Effect of titania content and the change of the surface by applying the biomimetic coating on the mechanical properties of the composite Y-TZP/TiO2

Os objetivos desse trabalho foram: 1) determinar o efeito do conteúdo de titânia em mol % (zero, 10 e 30) na área de superfície específica (SBET), no tamanho dos aglomerados e na intensidade dos picos correspondentes às fases cristalinas presentes no pó cerâmico de Y-TZP/TiO2; 2) determinar o efeito do conteúdo de titânia em mol % (zero, 10 e 30) na microestrutura, densidade, densidade relativa, módulo de elasticidade, coeficiente de Poisson, módulo de Weibull (m) e resistência à flexão (f) de pastilhas cerâmicas sinterizadas de Y-TZP/TiO2 e, 3) determinar o efeito do recobrimento biomimético no módulo de Weibull (m) e na resistência á flexão de pastilhas cerâmicas sinterizadas de Y-TZP/TiO2. Os pós foram produzidos por meio de uma rota de co-precipitação, obtendo-se três composições do compósito Y-TZP/TiO2, que foram de zero (T0), 10 (T10) e 30 (T30) % mol de titânia. O pó produzido foi prensado (50 MPa) para produzir pastilhas de 15 mm de diâmetro e sinterizado a 1400 °C por 2 horas. Após o polimento com solução diamantada de 45 m, as pastilhas (n=60 para cada grupo) ficaram com aproximadamente 12 mm de diâmetro e 1,0 mm de espessura. Metade das pastilhas foram submetidas ao recobrimento biomimético (sete dias em solução de silicato de sódio e sete dias em solução de 1,5 SBF-simulated body fluid). Os pós foram caracterizados por difração de raios-X (DRX), espalhamento a laser, adsorção gasosa e microscopia eletrônica de varredura (MEV). As pastilhas foram caracterizadas pelo método de Archimedes, pulso-eco ultra-ssônico, MEV, DRX e para a análise de Weibull, as pastilhas foram submetidas ao ensaio de resistência à flexão biaxial em saliva artificial a 37°C. Os resultados mostraram que todos os pós apresentaram zircônia monoclínica e tetragonal na sua composição e uma área de superfície específica superior a 42 m2/g. A adição de titânia favoreceu a formação de aglomerados maiores e com uma distribuição bimodal.

Em todas as pastilhas foram detectadas zircônia monoclínica e tetragonal, enquanto no grupo T30 também foi detectada a fase de titanato de zircônia (ZrTiO4). O grupo T0 apresentou os maiores valores de densidade medida (6,05 g/cm3), densidade relativa (99,0%), módulo de elasticidade (213 GPa) e resistência à flexão (815 MPa). A adição de titânia reduziu significativamente a densidade medida (5,45 g/cm3 para T10 e 5,15 g/cm3 para T30) a densidade relativa (94,4% para T10 e 96,3% para o T30) o módulo de elasticidade (156 GPa para T10 e 134 GPa para o T30) e a resistência à flexão (455 MPa para o grupo T10 e 336 MPa para o grupo T30) do compósito Y-TZP/TiO2. O grupo T30 apresentou um módulo de Weibull (11,7) e um coeficiente de Poisson (0,34) significativamente superior ao grupo T0 (6,4 e 0,31, respectivamente). Foi observado que o recobrimento biomimético promoveu a formação de glóbulos de hidroxiapatita distribuídos de forma heterogênea na superfície do material e que esse tratamento não alterou significativamente a resistência à flexão e o módulo de Weibull do compósito Y-TZP/TiO2. Conclui-se que a adição de titânia afetou as propriedades estudas do pó e das pastilhas do compósito de Y-TZP/TiO2. Além disso, o compósito pode ser recoberto com uma camada hidroxiapatita sem ter sua confiabilidade estrutural afetada.

The objectives of this study were: 1) to determine the effect of titania content in mol% (zero, 10 and 30) in the specific surface area (SBET), the size of the agglomerates and the intensity of the peaks corresponding to crystalline phase present in the ceramic powder of Y-TZP/TiO2; 2) to determine the effect of the content in mol% of titania (zero, 10 and 30) in the microstructure, density, relative density, modulus of elasticity, Poisson's ratio, Weibull modulus (m) and flexural strength (f) of ceramic discs sintered from Y-TZP/TiO2 and 3) to determine the effect of biomimetic coating on the Weibull modulus (m) and the flexural strength of the sintered ceramic discs of Y-TZP/TiO2. The powders were produced by a co-precipitation route, in order to obtain the composite Y-TZP/TiO2 with three compositions, containing zero (T0), 10 (T10) and 30 (T30) mol% titania. The produced powder was pressed (50 MPa) into discs of 15 mm diameter and sintered at 1400 °C for 2 hours. After polishing with diamond solution of 45 m, the discs (n = 60 for each group) were approximately 12 mm in diameter and 1.0 mm-thick. Half of the discs were subjected to biomimetic coating (seven days with sodium silicate solution and seven days in 1,5 SBF-simulated body fluid solution ). The powders were characterized by X-ray diffraction (XRD), laser scattering, gas adsorption and scanning electron microscopy (SEM). The discs were characterized by the Archimedes method, ultrasonic pulse-echo, SEM, XRD and for the Weibull analysis, the discs were subjected to the test of biaxial flexural strength in artificial saliva at 37 °C. The results showed that all powders had monoclinic and tetragonal zirconia in their composition, and a specific surface area greater than 42 m2/g.

Avaliação do potencial remineralizante de pastas e soluções com compostos bioativos no esmalte dental bovino submetido a ciclos de desafio erosivo / Remineralizing effectiveness of different bioactive principles in bovine enamel subjected to acidic challenges

O objetivo deste estudo foi avaliar in vitro por meio da Fluorescência de Raios X por Dispersão de Energia (XRF), Microdureza Vickers (MV) e Microscopia Eletrônica de Varredura (MEV) o efeito remineralizante de diferentes princípios bioativos, tais quais, nanopartículas de hidroxiapatita de cálcio (nanoHAp) associadas ou não a fluoreto, fosfopeptídeos de caseína do leite e fosfato de cálcio amorfo (CPP-ACP) associados ou não a fluoreto, fluoreto de sódio e saliva no esmalte dental bovino submetido a ciclagem des-remineralizante simulando lesão erosiva por alto desafio ácido. Foram obtidos 58 corpos de prova (CP) a partir de 58 incisivos bovinos que foram divididos aleatoriamente em 8 grupos, com 7 CP cada um e 2 CP para obtenção de imagem em MEV do esmalte hígido. Cada grupo foi denominado conforme os respectivos tratamentos a serem utilizados. Grupo 1 (G1) Controle; Grupo 2 (G2) Desensibilize Nano P experimental (nanopartículas de hidroxiapatita de cálcio); Grupo 3 (G3) Desensibilize Nano P (nanopartículas de hidroxiapatita de cálcio e flúor); Grupo4 (G4) GC Tooth Mousse (CPP-ACP, fosfopeptídios de caseína e fosfato de cálcio amorfo –Recaldent ™); Grupo 5 (G5) GC Tooth Mousse Plus (CPP-ACP, fosfopeptídios de caseína e fosfato de cálcio amorfo –Recaldent ™ + 900 ppm de flúor); Grupo 6 (G6) solução aquosa de fluoreto de sódio (0,05%); Grupo 7 (G7) solução aquosa de nanopartículas de hidroxiapatita de cálcio (0,375%) e Grupo 8 (G8) solução aquosa de nanopartículas de hidroxiapatita de cálcio (0,375%) + flúor (0,05%). Foram obtidos os valores de XRF e MV antes e depois do tratamento. Durante um período experimental de 10 dias, os CPs foram submetidos a um processo cíclico de des-remineralização incluindo vários ataques diários com ácido cítrico 0,05M (pH 2,3), 6 vezes de 2 minutos ao dia, bem como as aplicações das soluções teste e períodos de remineralização em saliva artificial. O tempo entre os ciclos ...

The aim of this study was to evaluate in vitro by X-ray fluorescence technique (XRF), surface microhardness (SMH) and SEM the remineralizing effect of different bioactive principles.We used 58bovine incisors that were sectioned into fragments (CP) and randomly divided into 8 groups. All teeth were initially evaluated to obtain the count of elements phosphorus (P) and calcium (Ca) interpreted from a range of X-Ray Fluorescence obtained by Artax ™ 200 and to obtain the initial SMH. Over a 10-day experimental period, the enamel samples weresubjected to erosive demineralization that was performed by immersion in 250 ml 0.05 M citric acid (pH 2.3) for 6 X 2 min per day. Subsequently, the samples were rinsed with distilled water for 1 min and afterwards received the corresponding treatments Group 1 (G1) Positive control; Group 2 (G2) Experimental Desensibilize Nano P (nanoparticles of calcium hydroxyapatite); Group 3 (G3) Desensibilize Nano P (nanoparticles of calcium hydroxyapatite and Fluor); Group 4 (G4) Recaldent: GC Tooth Mousse (CPP-ACP fosfopeptídios casein and amorphous calcium phosphate-Recaldent ™), Group 5 (G5) GC Tooth Mousse (CPP-ACP fosfopeptides casein and amorphous calcium phosphate-Recaldent ™ and 900 ppm Fluor); Group 6 (G6) NaF aqueous solution; (G7) nanoHAp aqueous solution and Group 8 (G8) nanoHAp + NaF aqueous solution. The samples were rinsed again with distilled water for 1 min and stored in artificial saliva. The time between cycles was 1.5 h. In the control group, the samples were eroded 6 X 2 min per day and stored in artificial saliva. All CP were evaluated again. SEM images for surface analysis were obtained after treatment. Through statistical analysis by Student t test ( p = 0.05 ) , the following results were found: control group had a severe demineralization, there was an increase in the count of P in all treated groups except G1 , that was an increase in Ca count in all treated ...

Avaliação do potencial remineralizante de pastas e soluções com compostos bioativos no esmalte dental bovino submetido a ciclos de desafio erosivo / Remineralizing effectiveness of different bioactive principles in bovine enamel subjected to acidic challenges

O objetivo deste estudo foi avaliar in vitro por meio da Fluorescência de Raios X por Dispersão de Energia (XRF), Microdureza Vickers (MV) e Microscopia Eletrônica de Varredura (MEV) o efeito remineralizante de diferentes princípios bioativos, tais quais, nanopartículas de hidroxiapatita de cálcio (nanoHAp) associadas ou não a fluoreto, fosfopeptídeos de caseína do leite e fosfato de cálcio amorfo (CPP-ACP) associados ou não a fluoreto, fluoreto de sódio e saliva no esmalte dental bovino submetido a ciclagem des-remineralizante simulando lesão erosiva por alto desafio ácido. Foram obtidos 58 corpos de prova (CP) a partir de 58 incisivos bovinos que foram divididos aleatoriamente em 8 grupos, com 7 CP cada um e 2 CP para obtenção de imagem em MEV do esmalte hígido. Cada grupo foi denominado conforme os respectivos tratamentos a serem utilizados. Grupo 1 (G1) Controle; Grupo 2 (G2) Desensibilize Nano P experimental (nanopartículas de hidroxiapatita de cálcio); Grupo 3 (G3) Desensibilize Nano P (nanopartículas de hidroxiapatita de cálcio e flúor); Grupo4 (G4) GC Tooth Mousse (CPP-ACP, fosfopeptídios de caseína e fosfato de cálcio amorfo –Recaldent ™); Grupo 5 (G5) GC Tooth Mousse Plus (CPP-ACP, fosfopeptídios de caseína e fosfato de cálcio amorfo –Recaldent ™ + 900 ppm de flúor); Grupo 6 (G6) solução aquosa de fluoreto de sódio (0,05%); Grupo 7 (G7) solução aquosa de nanopartículas de hidroxiapatita de cálcio (0,375%) e Grupo 8 (G8) solução aquosa de nanopartículas de hidroxiapatita de cálcio (0,375%) + flúor (0,05%). Foram obtidos os valores de XRF e MV antes e depois do tratamento. Durante um período experimental de 10 dias, os CPs foram submetidos a um processo cíclico de des-remineralização incluindo vários ataques diários com ácido cítrico 0,05M (pH 2,3), 6 vezes de 2 minutos ao dia, bem como as aplicações das soluções teste e períodos de remineralização em saliva artificial. O tempo entre os ciclos ...

The aim of this study was to evaluate in vitro by X-ray fluorescence technique (XRF), surface microhardness (SMH) and SEM the remineralizing effect of different bioactive principles.We used 58bovine incisors that were sectioned into fragments (CP) and randomly divided into 8 groups. All teeth were initially evaluated to obtain the count of elements phosphorus (P) and calcium (Ca) interpreted from a range of X-Ray Fluorescence obtained by Artax ™ 200 and to obtain the initial SMH. Over a 10-day experimental period, the enamel samples weresubjected to erosive demineralization that was performed by immersion in 250 ml 0.05 M citric acid (pH 2.3) for 6 X 2 min per day. Subsequently, the samples were rinsed with distilled water for 1 min and afterwards received the corresponding treatments Group 1 (G1) Positive control; Group 2 (G2) Experimental Desensibilize Nano P (nanoparticles of calcium hydroxyapatite); Group 3 (G3) Desensibilize Nano P (nanoparticles of calcium hydroxyapatite and Fluor); Group 4 (G4) Recaldent: GC Tooth Mousse (CPP-ACP fosfopeptídios casein and amorphous calcium phosphate-Recaldent ™), Group 5 (G5) GC Tooth Mousse (CPP-ACP fosfopeptides casein and amorphous calcium phosphate-Recaldent ™ and 900 ppm Fluor); Group 6 (G6) NaF aqueous solution; (G7) nanoHAp aqueous solution and Group 8 (G8) nanoHAp + NaF aqueous solution. The samples were rinsed again with distilled water for 1 min and stored in artificial saliva. The time between cycles was 1.5 h. In the control group, the samples were eroded 6 X 2 min per day and stored in artificial saliva. All CP were evaluated again. SEM images for surface analysis were obtained after treatment. Through statistical analysis by Student t test ( p = 0.05 ) , the following results were found: control group had a severe demineralization, there was an increase in the count of P in all treated groups except G1 , that was an increase in Ca count in all treated ...

Impact of Experimental Nano-HAP Pastes on Bovine Enamel and Dentin Submitted to a pH Cycling Model

This in vitro study evaluated the preventive potential of experimental pastes containing 10% and 20% hydroxyapatite nanoparticles (Nano-HAP), with or without fluoride, on dental demineralization. Bovine enamel (n=15) and root dentin (n=15) specimens were divided into 9 groups according to their surface hardness: control (without treatment), 20 Nanop paste (20% HAP), 20 Nanop paste plus (20% HAP + 0.2% NaF), 10 Nanop paste (10% HAP), 10 Nanop paste plus (10% HAP + 0.2% NaF), placebo paste (without fluoride and HAP), fluoride paste (0.2% NaF), MI paste (CPP-ACP, casein phosphopeptide-amorphous calcium phosphate), and MI paste plus (CPP-ACP + 0.2% NaF). Both MI pastes were included as commercial control products containing calcium phosphate. The specimens were treated with the pastes twice a day (1 min), before and after demineralization. The specimens were subjected to a pH-cycling model (demineralization–6-8 h/ remineralization-16-18 h a day) for 7 days. The dental subsurface demineralization was analyzed using cross-sectional hardness (kgf/mm 2 , depth 10-220 µm). Data were tested using repeated-measures two-way ANOVA and Bonferroni's test (p<0.05). The only treatment able to reduce the loss of enamel and dentin subsurface hardness was fluoride paste (0.2% NaF), which differed significantly from the control at 30- and 50-µm depth (p<0.0001). The other treatments were not different from each other or compared with the control. The experimental Nanop pastes, regardless of the addition of fluoride, were unable to reduce dental demineralization in vitro.

Este estudo in vitro avaliou o potencial de pastas experimentais contendo nanopartículas de hidroxiapatita a 10% e 20% (Nano-HAP), com ou sem fluoreto, na prevenção da desmineralização dentária. Espécimes de esmalte (n=15) e de dentina radicular (n=15) bovinos foram divididos em nove grupos de acordo com o valor de dureza superficial: controle (sem tratamento), pasta Nanop 20 (HAP 20%), pasta Nanop 20 plus (HAP 20% + NaF 0,2%), pasta Nanop 10 (HAP 10%), pasta Nanop 10 plus (HAP 10% + NaF 0,2%), pasta placebo (sem F e HAP), pasta fluoretada (NaF 0,2%), pasta MI (CPP-ACP, fosfopeptídio da caseína-fosfato de cálcio amorfo), e pasta MI plus (CPP-ACP + NaF 0,2%). As duas pastas MI foram inclusas como grupos controles comerciais contendo fosfato de cálcio. Os espécimes foram tratados com as pastas duas vezes ao dia (1 min), antes e após a desmineralização. Os espécimes foram submetidos a um modelo de ciclagem de pH (desmineralização 6-8 h/ remineralização 16-18 h por dia) durante sete dias. A desmineralização dentária de subsuperfície foi avaliada através da dureza longitudinal (kgf/mm 2 , profundidade de 10-220 µm). Os dados foram analisados utilizando ANOVA a dois critérios e teste de Bonferroni (p<0,05). O único tratamento capaz de reduzir a perda da dureza de subsuperfície do esmalte e da dentina foi a pasta fluoretada (NaF 0,2%), a qual diferiu significativamente do controle nas profundidades de 30 e 50 µm da superfície (p<0,0001). Os outros tratamentos não foram diferentes entre si ou quando comparados ao controle. As pastas experimentais Nanop, independentemente da presença de fluoreto, não foram capazes de reduzir a desmineralização dentária in vitro.

Study on nano-structured hydroxyapatite/zirconia stabilized yttria on healing of articular cartilage defect in rabbit

PURPOSE: Articular Cartilage has limited potential for self-repair and tissue engineering approaches attempt to repair articular cartilage by scaffolds. We hypothesized that the combined hydroxyapatite and zirconia stabilized yttria would enhance the quality of cartilage healing. METHODS: In ten New Zealand white rabbits bilateral full-thickness osteochondral defect, 4 mm in diameter and 3 mm depth, was created on the articular cartilage of the patellar groove of the distal femur. In group I the scaffold was implanted into the right stifle and the same defect was created in the left stifle without any transplant (group II). Specimens were harvested at 12 weeks after implantation, examined histologically for morphologic features, and stained immunohistochemically for type-II collagen. RESULTS: In group I the defect was filled with a white translucent cartilage tissue In contrast, the defects in the group II remained almost empty. In the group I, the defects were mostly filled with hyaline-like cartilage evidenced but defects in group II were filled with fibrous tissue with surface irregularities. Positive immunohistochemical staining of type-II collagen was observed in group I and it was absent in the control group. CONCLUSION: The hydroxyapatite/yttria stabilized zirconia scaffold would be an effective scaffold for cartilage tissue engineering.

In vitro evaluation of three different biomaterials as scaffolds for canine mesenchymal stem cells

PURPOSE: To evaluate in vitro ability the of three different biomaterials - purified hydroxyapatite, demineralized bone matrix and castor oil-based polyurethane - as biocompatible 3D scaffolds for canine bone marrow mesenchymal stem cell (MSC) intending bone tissue engineering. METHODS: MSCs were isolated from canine bone marrow, characterized and cultivated for seven days with the biomaterials. Cell proliferation and adhesion to the biomaterial surface were evaluated by scanning electron microscopy while differentiation into osteogenic lineage was evaluated by Alizarin Red staining and Sp7/Osterix surface antibody marker. RESULTS: The biomaterials allowed cellular growth, attachment and proliferation. Osteogenic differentiation occurred in the presence of hydroxyapatite, and matrix deposition commenced in the presence of the castor oil-based polyurethane. CONCLUSION: All the tested biomaterials may be used as mesenchymal stem cell scaffolds in cell-based orthopedic reconstructive therapy.

Avaliação de novos tratamentos preventivos da erosão e abrasão do esmalte e da dentina / Evaluation of new preventive treatments for erosion and abrasion of enamel and dentin

Este trabalho, conduzido na forma de 2 subprojetos, avaliou: 1) o potencial preventivo de pastas à base de hidroxiapatita (nanopartículas de fosfato de cálcio) sobre a erosão e a abrasão do esmalte e dentina bovinos in vitro e in situ e 2) o efeito de um bochecho com solução de lactato de cálcio antes da escovação com dentifrício fluoretado sobre a erosão associada ou não à abrasão do esmalte e dentina bovinos in vitro e in situ. Na fase in vitro do 1o subprojeto, submeteram-se blocos de esmalte e dentina bovinos, por 5 dias, à erosão (coca-cola, pH 2,6, 4x/dia, 90s cada) + abrasão (escova elétrica + solução do dentifrício sem flúor, 10s cada, 2x/dia) e os tratamentos foram realizados após a abrasão, através da aplicação das seguintes pastas sobre os blocos (3 min, 2x/dia): 10% HAP, 10% HAP + 0,2% NaF, 20% HAP, 20% HAP + 0,2% NaF, 20% HAP + 2% NaF, placebo, 0,2% NaF, 2% NaF, MI paste, MI paste plus e controle. Na fase in situ, (4 fases, 5 dias/cada), 12 voluntários utilizaram dispositivo intrabucal palatino contendo 4 blocos de dentina e 4 de esmalte bovinos divididos nas condições: erosão e erosão+abrasão. Em cada fase foi feito tratamento com uma das seguintes pastas: 10% HAP, 10% HAP + 0,2% NaF, MI paste plus ou Placebo. O protocolo erosivo e abrasivo foi semelhante ao in vitro. No 2o subprojeto, a fase in vitro foi semelhante ao subprojeto 1, porém apresentou as condições erosão e erosão+abrasão. O estudo compreendeu os seguintes tratamentos: BCa + DF, BCa + DP, BP + DF e BP + DP. Após erosão, os blocos foram imersos em água deionizada (BP) ou solução de lactato de cálcio 150 mM (BCa; 1 min, sob agitação). Na condição erosão apenas, a solução de dentifrício fluoretado (DF) ou placebo (DP) foi pipetada sobre as amostras. A fase in situ foi semelhante ao experimento in vitro, porém com 15 voluntários e escovação por 15 s. A variável de resposta para os 2 subprojetos foi a análise de desgaste, avaliada por perfilometria (μm) e para a fase in situ...

This study, conducted in the form of two subprojects, evaluated: 1) the preventive potential of hydroxyapatite-based (calcium phosphate nanoparticles) pastes on erosion and abrasion of bovine enamel and dentin in vitro e in situ and 2) the effect of rinsing with a solution of calcium lactate before brushing with fluoride toothpaste on erosion associated or not with abrasion of bovine enamel and dentin in vitro e in situ. In the in vitro phase of the 1st subproject, bovine enamel and dentin blocks were submitted to erosion (coca-cola, pH 2.6, 4x/day, 90s each) + abrasion (electric toothbrush + fluoride-free toothpaste slurry, 10s each, 2x/day) for 5 days. Treatments were performed after abrasion, by applying the following pastes on the blocks (3 min, 2x/day): 10% HAP, 10% HAP + 0.2% NaF, 20% HAP, 20% HAP + 0.2% NaF, 20% HAP + 2% NaF, placebo, 0.2% NaF, 2% NaF, MI paste, MI paste plus and control. In the in situ phase (4 phases, 5 days each), 12 volunteers used intraoral palatal appliance containing four blocks of dentin and four blocks enamel divided into conditions erosion and erosion+abrasion. In each phase, treatment was done with one of the following pastes: 10% HAP, 10% HAP + 0.2% NaF, MI paste plus or Placebo. The erosive and abrasive protocol was similar to the in vitro phase. In the 2nd subproject, the in vitro phase was similar to subproject 1, but presented both conditions erosion and erosion + abrasion. The study included the following treatments: BCa + DF, BCa + DP, BP + DF e BP + DP. After erosion, the blocks were immersed in deionized water (BP) or calcium lactate solution 150 mM (BCa; 1 min, stirring). For the condition erosion only, the slurry of fluoride (DF) or placebo (DP) dentifrice was pipetted on the samples. The in situ phase was similar to the in vitro experiment, but 15 volunteers were included and brushing was conducted for 15 s. The response variable for the two subprojects was wear, evaluated by profilometry (μm)...

Comparação da dinâmica da resposta celular utilizando dois diferentes biomateriais: Nanopartículas de Hidroxiapatita e Agregado Trióxido Mineral (MTA) / Comparison of dynamic cellular response using to different biomaterials: Nanobeads of Hidroxyapatite and Mineral Trioxide Aggregate (MTA)

As células da polpa dental têm o potencial de responder a estímulos externos e reparar o tecido dentário lesionado. Nos dentes, as lesões cariosas profundas e as lesões traumáticas são frequentes e resultam em alterações pulpares. Com o desenvolvimento da ciência e a busca de formas inovadoras de tratamento utilizando biomateriais de tamanho cada vez menor, verificar a biocompatibilidade desses materiais antes da aplicação clínica se mostra necessário e promissor. Assim, a finalidade deste estudo foi avaliar a biocompatibilidade de uma nova nanopartícula de hidroxiapatita utilizando células pulpares humanas em cultura. As Nanopartículas de Hidroxiapatita (HAp) utilizadas em nosso estudo são um material novo e ainda não disponível para a prática clínica. Como parâmetro comparativo, foi utilizado o material já consagrado na Odontologia para tratamentos endodônticos, o Agregado Trióxido Mineral (MTA). Para tanto, foram realizados testes de biocompatibilidade (MTS (3-(4,5-dimetiltiazol-2-y)5-(3-carboximetoxifenil)-2-(4-sulfofenil-2H-tetrazolio)). Foi preparada uma solução de material na concentração de 0,1g/ml diluído em meio de cultura, proporção preconizada pela norma ISO 10.993-12 (ISO, 1996). Esta solução foi diluída em 3 diferentes concentrações (1/10, 1/100 e 1/1000). Também foram realizados testes de migração celular e testes de capacidade de diferenciação, na concentração de 1/100

Como resultados pudemos verificar que as células da polpa foram viáveis quando expostas a diferentes concentrações de HAp, proliferaram mais quando tratadas com HAp na concentração de 1/100, migraram em direção aos materiais estudados e diferenciaram-se em tecido mineralizado quando em contato direto com ambos materiais estudados. Concluímos que o novo material testado é biocompatível e capaz de induzir mineralização em células de polpa dental sugerindo que as HAp podem ter aplicações clínicas futuras em tecidos mineralizados como osso e dente

The dental pulp cells have the potential to respond to external stimuli and repair the dental tissue injury. On teeth, deep carious lesions and traumatic injuries are common and result in pulp changes. With the development of science and the search for innovative treatment forms using reduced size biomaterials, to verify the biocompatibility of these materials before clinical application has become necessary and promising. Thus, the purpose of this study was to evaluate the biocompatibility of a new hydroxyapatite nanoparticle using human pulp cells in culture. The nanoparticles of hydroxyapatite (HAp) used in our study are new material and not yet available for clinical practice. As a comparator, we used the material already used in dentistry to root canal treatment, the Mineral Trioxide Aggregate (MTA). To do so, biocompatibility (MTS (3-(4,5-dimetiltiazol-2-y)5-(3-carboximetoxifenil)-2-(4-sulfofenil-2H-tetrazolio)). A solution of the material in a concentration of 0.1 g / ml diluted in culture medium recommended by ISO 10993-12 (ISO 1996) standard was prepared. This solution was diluted in three different concentrations (1/10, 1/100 and 1/1000). Were also performed cell migration and differentiation capacity assays at a concentration of 1/100

As results, we found that the pulp cells were viable when exposed to different concentrations of HAp, they proliferated more when treated with 1/100 HAp concentration, migrated toward the studied materials and differed into mineralized tissue when there was direct contact with both materials studied. We conclude that the new material tested is biocompatible and able to induce mineralization of dental pulp cells suggesting that the HAp may have future clinical applications in mineralized tissues such as bone and tooth

Avaliação de novos tratamentos preventivos da erosão e abrasão do esmalte e da dentina / Evaluation of new preventive treatments for erosion and abrasion of enamel and dentin

Este trabalho, conduzido na forma de 2 subprojetos, avaliou: 1) o potencial preventivo de pastas à base de hidroxiapatita (nanopartículas de fosfato de cálcio) sobre a erosão e a abrasão do esmalte e dentina bovinos in vitro e in situ e 2) o efeito de um bochecho com solução de lactato de cálcio antes da escovação com dentifrício fluoretado sobre a erosão associada ou não à abrasão do esmalte e dentina bovinos in vitro e in situ. Na fase in vitro do 1o subprojeto, submeteram-se blocos de esmalte e dentina bovinos, por 5 dias, à erosão (coca-cola, pH 2,6, 4x/dia, 90s cada) + abrasão (escova elétrica + solução do dentifrício sem flúor, 10s cada, 2x/dia) e os tratamentos foram realizados após a abrasão, através da aplicação das seguintes pastas sobre os blocos (3 min, 2x/dia): 10% HAP, 10% HAP + 0,2% NaF, 20% HAP, 20% HAP + 0,2% NaF, 20% HAP + 2% NaF, placebo, 0,2% NaF, 2% NaF, MI paste, MI paste plus e controle. Na fase in situ, (4 fases, 5 dias/cada), 12 voluntários utilizaram dispositivo intrabucal palatino contendo 4 blocos de dentina e 4 de esmalte bovinos divididos nas condições: erosão e erosão+abrasão. Em cada fase foi feito tratamento com uma das seguintes pastas: 10% HAP, 10% HAP + 0,2% NaF, MI paste plus ou Placebo. O protocolo erosivo e abrasivo foi semelhante ao in vitro. No 2o subprojeto, a fase in vitro foi semelhante ao subprojeto 1, porém apresentou as condições erosão e erosão+abrasão. O estudo compreendeu os seguintes tratamentos: BCa + DF, BCa + DP, BP + DF e BP + DP. Após erosão, os blocos foram imersos em água deionizada (BP) ou solução de lactato de cálcio 150 mM (BCa; 1 min, sob agitação). Na condição erosão apenas, a solução de dentifrício fluoretado (DF) ou placebo (DP) foi pipetada sobre as amostras. A fase in situ foi semelhante ao experimento in vitro, porém com 15 voluntários e escovação por 15 s. A variável de resposta para os 2 subprojetos foi a análise de desgaste, avaliada por perfilometria (μm) e para a fase in situ...

This study, conducted in the form of two subprojects, evaluated: 1) the preventive potential of hydroxyapatite-based (calcium phosphate nanoparticles) pastes on erosion and abrasion of bovine enamel and dentin in vitro e in situ and 2) the effect of rinsing with a solution of calcium lactate before brushing with fluoride toothpaste on erosion associated or not with abrasion of bovine enamel and dentin in vitro e in situ. In the in vitro phase of the 1st subproject, bovine enamel and dentin blocks were submitted to erosion (coca-cola, pH 2.6, 4x/day, 90s each) + abrasion (electric toothbrush + fluoride-free toothpaste slurry, 10s each, 2x/day) for 5 days. Treatments were performed after abrasion, by applying the following pastes on the blocks (3 min, 2x/day): 10% HAP, 10% HAP + 0.2% NaF, 20% HAP, 20% HAP + 0.2% NaF, 20% HAP + 2% NaF, placebo, 0.2% NaF, 2% NaF, MI paste, MI paste plus and control. In the in situ phase (4 phases, 5 days each), 12 volunteers used intraoral palatal appliance containing four blocks of dentin and four blocks enamel divided into conditions erosion and erosion+abrasion. In each phase, treatment was done with one of the following pastes: 10% HAP, 10% HAP + 0.2% NaF, MI paste plus or Placebo. The erosive and abrasive protocol was similar to the in vitro phase. In the 2nd subproject, the in vitro phase was similar to subproject 1, but presented both conditions erosion and erosion + abrasion. The study included the following treatments: BCa + DF, BCa + DP, BP + DF e BP + DP. After erosion, the blocks were immersed in deionized water (BP) or calcium lactate solution 150 mM (BCa; 1 min, stirring). For the condition erosion only, the slurry of fluoride (DF) or placebo (DP) dentifrice was pipetted on the samples. The in situ phase was similar to the in vitro experiment, but 15 volunteers were included and brushing was conducted for 15 s. The response variable for the two subprojects was wear, evaluated by profilometry (μm)...