Academic literature on the topic 'Calcium hydroxide nanoparticles'

The purpose of this study was to evaluate the antibacterial efficacy of silver Nanoparticles, Nanoparticle calcium hydroxide and calcium hydroxide as intracanal medicament against Enterococcus faecalis bio film formed on root dentinThe Minimal inhibitory concentration test and Anti microbial test were conducted for silver nanoparticle, Nanoparticle calcium hydroxide. Teeth were inoculated with E.faecalis strains for 1month to establish a standard mono species bio film model. Biofilm formation is confirmed using SEM. The intracanal medicaments were placed inside the canal and colony forming units (CFU) were counted before and 7 days later the placement of the medicament.MIC for AGNP is 25µg/200µl and for NCH is 12.5µg/200µl. The Antimicrobial test conducted shows zone of inhibition about 11mm and 14mm for AGNP and NCH respectively at 500µg. The calcium hydroxides do not show any antibacterial activity at this concentration. In antibacterial efficacy test using CFU count, the AGNP and NCH shows 75% and 61% of antibacterial efficacy respectively whereas calcium hydroxide has exhibited just 11% of antibacterial efficacy. Silver Nanoparticles and nanoparticle calcium hydroxide had statistically significant difference in the reduction in the number of colonies when compared to calcium hydroxide by post hoc turkey test and p-value of <0.01 was considered as significant in this study.

Complete eradication of bacterial infection from the root canal with minimum or no effect on the microhardness of the dentin is desirable for the success of endodontic treatment. The effect of nanoparticle based intracanal medicaments on the root dentine microhardness was assessed. The medicaments used were combination of calcium hydroxide - silver nanoparticles, Combination of graphene oxide - silver nanoparticles, Calcium hydroxide and a control group. Vickers hardness value were evaluated and compared at coronal, middle and apical third level. Graphene oxide - silver nanoparticles based intracanal medicament showed least effect on the microhardness of the root dentin compared to calcium hydroxide and calcium hydroxide combined with silver nanoparticle based intracanal medicaments.

OBJECTIVE: To compare the in-vitro antibacterial effectiveness in terms of enterococcus faecalis elimination of conventional unmodified calcium hydroxide paste with an experimental calcium hydroxide impregnated with 1% silver nanoparticles. METHODOLOGY: This in vitro study was conducted during the period July 2019 - January 2020 at Materials Research Laboratory, Centralized Resource Laboratory (University of Peshawar) and Pathology Laboratory (Peshawar Medical College). Sixty human premolar teeth having single root with mature apices were obtained. These were distributed into two groups randomly (n=30); experimental group for testing the antibacterial efficacy of calcium hydroxide impregnated with 0.1% by weight silver nanoparticles and the other was used as a control group for testing the antibacterial efficacy of unmodified calcium hydroxide. Dentine specimens (size 4 x 4x 1mm) were prepared from the teeth using slow speed cutting saw machine. Smear layer was removed with EDTA. Specimens were autoclaved to sterilize them. Then each specimen was contaminated with enterococcus faecalis and incubated anaerobically for 24 hours at 37?C. After the application of medicaments, the zone of inhibition was measured and number of viable bacteria were determined using SEM. Statistical significance was calculated using t-test. p<0.05 was taken as significant. RESULTS: After the application of medicament, the zone of inhibition was greater (9.63mm) in experimental group when compared to control group (4mm) (p<0.001). Number of viable bacteria before application of medicament were 239 and 208 while after application of medicament reduced to 90 and 54 in control and experimental groups respectively (p<0.001). CONCLUSION: The addition of silver nanoparticles to calcium hydroxide significantly enhanced its potential to eliminate biofilm of enterococcus faecalis on dentin specimens. KEYWORDS: Silver nanoparticles, Calcium hydroxide, Root canal infections, Root canal medicament.

An application of hydroxide nanoparticles in preservation of cultural heritage attracted great interest. The nanodispersions of calcium, magnesium or barium hydroxides exhibit high performance in consolidation abilities. In this work we focused on preparation of magnesium and barium hydroxide nanoparticles. For the synthetic procedure we used acetate precursors and sodium hydroxide. Obtained particles were dispersed in 2-propanol. Hydroxide nanoparticles were characterized by powder X-Ray diffraction, infrared spectroscopy and scanning electron microscopy. It was observed that smaller particles were achieved in case of magnesium hydroxide. Presented work demonstrates that this reaction procedure can be applied for preparation of materials used in cultural heritage preservation.

The most common intracanal medication is calcium hydroxide. Its efficacy can be affected by a number of factors, including pH, serum proteins, collagen, and dentin. It's also ineffective against E. faecalis and fungus, lacks an anti-inflammatory component, and has mixed reviews when it comes to pain relief. Natural alternatives to synthetic intracanal medication are being researched at the moment. We evaluated the antioxidant and anti-inflammatory activity of green synthesized silver nanoparticle based intracanal medicaments. Silver nanoparticles integrated into calcium hydroxide and graphene oxide nanoparticles were the experimental groups and Calcium hydroxide served as the control. Antioxidant activity was determined using the DPPH and Nitric oxide assays, while anti-inflammatory activity was determined using the protein denaturation and Xanthine Oxidase Inhibition assays. Both experimental groups had higher antioxidant activity than the control group based on DPPH and Nitric oxide assays. Calcium hydroxide combined with silver nanoparticles demonstrated improved anti-inflammatory efficacy in a protein denaturation and Xanthine oxidase inhibition assay. Within the constraints of an in vitro study, it can be concluded that intracanal medicaments containing silver nanoparticles can be employed efficiently during root canal preparation. In comparison to standard calcium hydroxide-based intracanal medicaments, it has effective antioxidant and anti-inflammatory effects.

The current study examines the potential of using calcium and magnesium hydroxide nanoparticles synthetized through a quick precipitation method as soil stabilizers for improving the engineering properties of tropical residual soil. The engineering properties of untreated and nanoparticles-treated soil were studied by carrying out a series of geotechnical tests including compaction, Atterberg limits, falling head permeability, and unconfined compressive strength (UCS). The stabilization mechanisms associated with soil–chemical reactions were further explored by performing microstructural analyses such as x-ray diffraction (XRD), variable-pressure scanning electron microscope (VP-SEM), and energy-dispersive x-ray spectroscopy (EDX). The findings revealed that the calcium hydroxide and magnesium hydroxide nanoparticles improved the geotechnical properties of residual soils in terms of reduced hydraulic conductivity and increased UCS. The percentage reduction of the hydraulic conductivity of magnesium and calcium hydroxide nanoparticles-treated soils compared to untreated soil after seven weeks of permeation were 85.14% and 98.70%, respectively. The magnesium and calcium hydroxide nanoparticles-treated soils subjected to 14 days of curing recorded a percentage increase in the UCS of 148.05% and 180.17%, respectively compared to untreated soil. Hence, it can be concluded that both magnesium and calcium hydroxide nanoparticles can be effectively utilized as environmental-friendly stabilizers.

ABSTRACT Aim To evaluate pH and antibacterial activity of pastes with calcium hydroxide [Ca(OH)2] and zinc oxide (ZnO) microparticles (micro) or nanoparticles (nano) and association with 0.4% chlorhexidine against Enterococcus faecalis. Materials and methods The following pastes were analyzed: Ca(OH)2/ZnO micro, (2) Ca(OH)2/ZnO nano, (3) Ca(OH)2/ ZnO micro + 0.4% chlorhexidine, (4) Ca(OH)2/ZnO nano + 0.4% chlorhexidine. Antibacterial activity against E. faecalis was evaluated by agar diffusion test. The direct contact test on planktonic cells of E. faecalis was performed for 30 and 60 seconds. Root canals from bovine teeth were filled with the pastes and pH was evaluated after 1, 7, 14, 21, 30 and 60 days. The data obtained were submitted to the statistical tests analysis of variance (ANOVA) and Tukey or Kruskal-Wallis and Dunn test, with a 5% significance level. Results Calcium hydroxide and zinc oxide nano, and the pastes with 0.4% chlorhexidine were more effective in agar diffusion test. In the direct contact test, the pastes with chlorhexidine showed the highest effect after 30 seconds. All pastes eliminated E. faecalis after 60 seconds. All pastes promoted an increase in pH. The highest increase in pH was observed with nanoparticle medications after 1 and 7 days (p < 0.05). After this period, the pastes presented similar pH increase. Conclusion It was concluded that calcium hydroxide and zinc oxide nanoparticles promoted greater initial alkalinization. The antimicrobial activity of the pastes against E. faecalis is favored by the association with chlorhexidine. Clinical significance Although nanoparticles of calcium hydroxide and zinc oxide promoted antibacterial effect, the activity against E. faecalis is favored by association with chlorhexidine. How to cite this article Aguiar AS, Guerreiro-Tanomaru JM, Faria G, Leonardo RT, Tanomaru-Filho M. Antimicrobial Activity and pH of Calcium Hydroxide and Zinc Oxide Nanoparticles Intracanal Medication and Association with Chlorhexidine. J Contemp Dent Pract 2015;16(8):624-629.

The objective of this paper is to introduce a patented and eco-friendly method to synthesize aqueous suspension of all types of alkaline-earth metal hydroxides nanoparticles (NPs). This method is based on an ion exchange process; the exchange takes place at ambient temperature/pressure, starts from cheap or renewable reagents and, in one single step, results in the creation of the crystalline desired nanoparticles in only a few minutes. In terms of structural and morphological features, the synthesized nanoparticles are characterized by means of XRD-Rietveld refinement, FTIR, and TEM. In particular, we obtained pure and crystalline magnesium and calcium hydroxide suspensions, showing the typical brucite crystal structure with a hexagonal lamellar morphology and dimensions generally <100 nm. With respect to the strontium and barium hydroxide suspensions, we observed different kinds of hydroxides (either anhydrous and hydrate forms), characterized by orthorhombic or monoclinic crystal lattices with rod-like nanostructured morphologies. Despite the different morphologies, all synthesized nanoparticles appear constituted by a superimposition of primary nanoparticles, of dimensions ranging from a few to 15 nm, correlated to the increase in the atomic number of the alkaline earth metal.

In this study, calcium carbonate nanoparticles (CCNPs) and calcium oxide nanoparticles (CONPs) are synthesized by the carbonization/calcination of calcium oleate. CONPs are an essential inorganic material, and they are used as catalysts and as effective chemisorbents for toxic gases. CCNPs are widely used in plastics, printing ink, and medicines. Here, calcium oleate is used as a starting material for the preparation of CCNPs and CONPs. This calcium oleate is prepared from calcium hydroxide and oleic acid in ethanol under mild reflux conditions. The effect of the calcination temperature of calcium oleate is examined during the synthesis of CCNPs and CONPs. By simple carbonization/calcination, calcite-type CCNPs and CONPs are prepared at <550 °C and >600 °C, respectively. The synthesized nanomaterials are analyzed by various physicochemical characterization techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA) with derivative thermogravimetry (DTG), and scanning electron microscopy (SEM) with energy dispersive X-ray analysis. An X-ray diffractometer and the Scherrer formula are used to analyze the crystalline phase and crystallite size of prepared nanoparticles. TGA techniques confirm the thermal stability of the calcium oleate, CCNPs, and CONPs. The SEM analysis illustrates the dispersive behavior and cubic/spherical morphologies of CCNPs/CONPs. Furthermore, the obtained results are compared to the CCNP and CONP samples prepared using calcium hydroxide. As a result, the carbonization/calcination of calcium oleate produces monodispersed CONPs, which are then compared to the CONPs from calcium hydroxide. Additionally, from calcium oleate, CONPs can be prepared on a large scale in a cheap, convenient way, using simple equipment which can be applied in various applications.

Background: Endodontic is a treatment that aims to eliminate bacteria from the root canal system. One of the bacteria that causes root canal treatment failure is Enterococcus faecalis. Chemomechanical preparation and root canal irrigation are not sufficient to eliminate bacteria completely, so root canal medication is necessary to make it more efficient. Moringa leaves contain tannins, flavonoids and saponins which have antibacterial properties. Objective: To determine whether moringa leaf nanoparticle paste had antibacterial effectiveness against the bacterium E.faecalis. Method: Experimental laboratory with posttest with control group design with Kirby-Bauer method. The sample consisted of moringa leaf nanoparticles with concentrations of 1% and 2.5%, calcium hydroxide and aquadest with each of them being repeated 3 times. The diameter of the inhibition zone was de-termined based on the inhibitory ability of the bacteria saturated on MHA agar media. Results: the result showed that the ave-rage diameter of the inhibition zone of moringa leaf nanoparticle paste with concentrations of 1% was 8.48 mm, 2.5% was 9.17 mm and calcium hydroxide was 10.2 mm. Data processing showed that the 2.5% moringa leaf nanoparticle paste group had the same antibacterial effect as the calcium hydroxide group. Conclusion: Moringa leaf nanoparticle paste (Moringa oleifera) with concentrations of 1% and 2.5% was quite effective in inhibiting the growth of E.faecalis.

Aim: The aim of the current study was to develop two formulations loading calcium hydroxide (Ca(OH)₂) and Clobetasol Propionate into poly lactic-co-glycolic acid (PLGA) biodegradable nanoparticles (NPs) to be used in the field of endodontics as an intracanal medications, including NPs optimization and characterization, plus drug release profile of the NPs compared to free drug counterpart. Additionally, comparison of the depth and area of penetration of the NPs inside the dentinal tubules against the free drug was carried out. Furthermore, the therapeutic efficacy for both formulations were examined using antibacterial and anti-inflammatory assays. Methodology: NPs were prepared using the solvent displacement method. Optimization of the NPs was carried out with a central composite design to obtain a final optimized formulation. The NPs morphology was examined under transmission electron microscopy (TEM), plus characterization was done by x-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Moreover, the optimal conditions and cryoprotectants for freeze drying of the NPs were examined and tested. The drug release profile of the NPs and free drug was evaluated up to 48 hours. Additionally, the depth and area of penetration inside the dentinal tubules was examined for both the NPs and free drug. Antibacterial testing was performed on the antibacterial NPs to evaluate their efficacy in eliminating different bacterial strains. Agar disk-diffusion and broth dilution were used to determine the inhibition growth zones and the minimal inhibitory concentration (MIC). Likewise, anti-inflammatory testing was performed on the Clobetasol Propionate anti-inflammatory NPs, in which their response and reaction against inflammatory cells, in particular against macrophages was tested using the enzyme-linked immunosorbent assay (ELISA) to examine the cytokine release of IL-1β and TNF-α. Results: Using the solvent displacement method, both formulations of NPs were successfully optimized. The characteristics of the NPs utilizing the optimized formula showed a polidpsersity index (PI) value lower than 0.2, characteristic of monodisperse systems and an average size below 200 nm along with a highly negative surface charge (measured as zeta potential, ZP) and maximum entrapment efficiency (EE) percentage. For both the Ca(OH)₂/PLGA and the clobetasol propionate/PLGA NPs, the characterization of the NPs was performed, and the spherical morphology was confirmed using TEM. Moreover, interaction studies were carried out including XRD, FTIR and DSC to examine the profile of the NPs. These studies confirmed that no covalent bonds were formed during the preparation process and that the drug appeared to be encapsulated inside the NPs. Examining the drug release profile for the Ca(OH)₂/PLGA NPs, the Ca(OH)₂ NPs exhibited a prolonged and steady release with higher concentrations than those obtained with the free Ca(OH)₂, that remained stable up to 48 hours. Moreover, clobetasol propionate/PLGA NPs, exhibited a prolonged and steady release with only around 21 % of the encapsuled drug released after 48 hours, in comparison the free drug that was completely released after just 6 hours. For the freeze drying of the Ca(OH)₂/PLGA NPs, the combination of 5% of (2-Hydroxypropyl)-β-cyclodextrin and 15% D-mannitol gave rise to the most stable outcome and the best appearance after lyophilization being able to recover the initial physicochemical characteristics of the NPs after their resuspension. Unfortunately, for the clobetasol propionate/PLGA NPs, we were not able to achieve a suitable combination. Using the confocal laser scanning microscopy, it was shown that both the Ca(OH)₂/PLGA and the clobetasol propionate/PLGA NPs had a better depth and area of penetration inside the dentinal tubules when compared to the free drug. Plus, the NPs displayed higher values mean fluorescence intensity (MFI) and integrated density compared to the free drug. Assessing the antibacterial efficiency of the Ca(OH)₂/PLGA NPs using the agar diffusion test, it was noted that the NPs showed clear maximal zones of growth inhibition around the filter papers comparable only to the positive group of antibiotics. Additionally, the MIC of the NPs was measured in regard to inhibiting bacterial growth for 3 bacterial species. It was noted that after 24 hours of incubation the NPs were able to inhibit bacterial growth at all tested concentrations. The anti-inflammatory capacity of the clobetasol propionate/PLGA NPs was also examined, in which ELISA assays were used to evaluate the inflammatory cytokines release of the macrophages in response to the NPs. The releases of TNF-α was reduced considerably to almost undetectable amounts with NPs compared to the LPS negative control, displaying results similar and even less than the TCP positive control after 48 hours. However, resulted in the release of IL-1β in higher amounts which were similar to the TCP positive control and lesser than the LPS negative control group. Additionally, the inflammatory cytokines release of IL-1β and TNF-α from the LPS pretreated macrophages, was not reduced with the NPs at all tested concertation to limits below the amounts obtained by the LPS pretreated macrophages or the TCP positive control group after 48 hours. Conclusions: In the present study, Ca(OH)₂ loaded PLGA NPs and clobetasol propionate loaded PLGA NPs were successfully optimized and characterized, and their therapeutic efficacy was tested with aims to increase the antibacterial and anti-inflammatory effect through controlled drug release and reach areas of complicated root canal anatomy due to the smaller mean nanoscopic size. However, further future studies are still required in order for the developed NPs to take the next step to be utilized in a clinical condition and to achieve its goal as an intracanal medicament.
Objetivo: El objetivo del presente estudio ha sido el desarrollo de dos formulaciones encapsulando hidróxido de calcio (Ca(OH)₂) y clobetasol en nanopratículas (NPs) biodegradables de ácido poli(láctico-co-glicólico) (PLGA) para ser usadas en el campo de la endodoncia como medicación intra-conducto, incluyendo la optimización y caracterización de las NPs y el perfil de liberación del principio activo en comparación con el fármaco libre. Adicionalmente se comparó la cantidad y el área de penetración de las NPs en el interior de los túbulos dentinarios. Las eficacias terapéuticas de ambas formulaciones fueron examinadas mediante test antibacterianos y antiinflamatorios. Metodología: Las NPs fueron preparadas por el método de desplazamiento de solvente. La optimización fue realizada mediante un diseño factorial central compuesto obtenido la formulación final. Se realizó un estudio de la morfología de las NP mediante microscopía electrónica de transmisión (MET). Además, las NPs se caracterizaron mediante cristalografía de Rayos X, espectroscopía infrarroja de Fourier y calorimetría diferencial de barrido. También se examinaron y llevaron a cabo el estudio de las condiciones óptimas para el proceso de liofilización de las NP. Se evaluó el perfil de liberación del fármaco desde el interior de las NP comparándolo con el del fármaco libre, hasta las 48 horas. El examen de penetración dentro de los túbulos dentinarios de las NP en comparación con el fármaco libre se realizó mediante microscopía confocal. Para evaluar la capacidad antibacteriana de las NP de hidróxido de calcio se realizaron los test de método Kirby-Bauer (Test de difusión en agar) y la concentración mínima inhibitoria (CMI). En las NP de propinado de clobetasol se evaluó su respuesta y reacción frente a células inflamatorias, en particular frente a macrófagos, utilizando el ensayo inmunoabsorbente ligado a enzimas (ELISA) para examinar la liberación de citocinas de IL -1β y TNF-α. Resultados: Las formulaciones de NPs con hidrócido de calcio y clobetasol se prepararon utilizando el método de desplazamiento de solvente. Las características de las formulaciones optimizadas presentaron una población homogénea con un valor de índice de polidispersión (PI inferior a 0,2) y tamaño promedio adecuado, inferior a 200 nm. Además, su carga superficial medida en base al potencial zeta fue altamente negativa y se obtuvo una eficiencia de asociación elevada en ambos casos, superior para el clobetasol. Tanto para las NP de Ca (OH) ₂ / PLGA como para las NP de propionato de clobetasol / PLGA, se confirmó su morfología esférica y su superficie lisa mediante MET. Se realizaron diferentes estudios de interacción fisicoquímica confirmando que ambos fármacos se encontraban en el interior de la matriz polimérica y que no se producían nuevos enlaces en la formación de los sistemas nanoestructurados. Se examinó el perfil de liberación para ambas formulaciones. En el caso de las NP de Ca (OH) ₂ / PLGA, las NP de Ca (OH) ₂ mostraron una liberación prolongada y constante del fármaco con concentraciones más altas que en el caso dl fármaco libre, que permanecieron estables hasta 48 horas después. Las NP de propionato de clobetasol / PLGA exhibieron una liberación prolongada y constante con una liberación del 21 % del fármaco encapsulado liberado después de 48 horas, en comparación con el fármaco libre que se liberó por completo después de solo 6 horas. Para la liofilización de las NP de Ca (OH) ₂ / PLGA, se obtuvo un resultado el mejor resultado con la combinación de 5% de (2-hidroxipropil) -β-ciclodextrina y 15% de D-manitol. Estas formulaciones pudieron ser resuspendidas de forma instantánea consiguiendo los parámetros originales. Desafortunadamente, para los NP de propionato de clobetasol / PLGA, no pudimos lograr una combinación adecuada de crioprotectores y condiciones de liofilización óptimas. Usando la microscopía confocal, se demostró que tanto el Ca (OH) ₂ / PLGA como el propionato de clobetasol / PLGA NP tenían una mejor profundidad y área de penetración dentro de los túbulos dentinarios en comparación con el fármaco libre. Además, los NP mostraron valores más altos de intensidad de fluorescencia media (mean fluorescence intensity, MFI) y densidad integrada en comparación con el fármaco libre. Al evaluar la eficacia antibacteriana de las NP de Ca (OH) ₂ / PLGA utilizando la prueba de difusión en agar, se observó que las NP mostraban zonas claras máximas de inhibición del crecimiento alrededor de los papeles de filtro comparables solo al grupo positivo de antibióticos. Además, se midió la concentración mínima inhibitoria (CMI) de las NP con respecto a la inhibición del crecimiento bacteriano para 3 especies bacterianas. Se observó que después de 24 horas de incubación, las NP inhibieron el crecimiento bacteriano en todas las concentraciones probadas. Se realizaron estudios para medir la capacidad antiinflamatoria de las NPs de propionato de clobetasol /PLGA, para lo cual se utilizaron test ELISA para evaluar la respuesta de los macrófagos en la liberación de citoquinas inflamatorias en presencia de las NP. Se observó que las liberaciones de TNF-α se redujeron considerablemente a cantidades casi indetectables con NPs en comparación con el control negativo (LPS), mostrando resultados similares e incluso menores que el control positivo (TCP) después de 48 horas. Sin embargo, se obtuvo la liberación de IL-1β en cantidades mayores que eran similares al control positivo de TCP y menores que al grupo de control negativo de LPS. La liberación de citoquinas inflamatorias de IL-1β y TNF-α de los macrófagos pretratados con LPS no se redujo con las NP en ninguna concertación probada a límites por debajo de las cantidades obtenidas por los macrófagos pretratados con LPS o el grupo de control positivo de TCP después de 48 horas. Conclusiones: En el presente estudio, las NP de PLGA encapsulando Ca(OH)₂ y las NP de PLGA encapsulando propionato de clobetasol han sido optimizadas y caracterizadas con éxito, y se ha probado su eficacia terapéutica con el objetivo de aumentar el efecto antibacteriano y antiinflamatorio. La penetración de las mismas en áreas de anatomía complicada del conducto radicular (túmulos dentinarios) ha sido demostrada, debido al tamaño nanoscópico de las mismas. Sin embargo, aún se requieren más estudios futuros para que las NP formuladas puedan ser utilizados en una condición clínica.

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Intracanal medication aims to eliminate micro-organisms present within the system of canals, making the repair of tissues damaged by microbial action. Despite the numerous drugs used, there is not an ideal drug. This study aimed to develop and characterize nanoparticles containing chlorhexidine. Furthermore, it aimed to evaluate its degradation when associated to calcium hydroxide, and to analyze their performance in vitro and in vivo. Solid lipid nanoparticles containing chlorhexidine were developed and characterized in concentrations of 0.2 and 0.5 % chlorhexidine (suspension and gel), showing average particle size values of 88.5 nm and 84.6 nm, respectively. The samples were stored for 90 days and remained stable at 5°C and room temperature, but unstable at 40°C. The free chlorhexidine concentration reduced in 33% when associated to calcium hydroxide after 14 days of analysis. O the other hand, nanoencapsulated chlorhexidine degraded only 10 % at the same conditions. The agar diffusion test against C. albicans and E. faecalis, for 72 h, showed smaller zone of inhibition but they increased size. Despite this seemed unfavorable, the MIC result showed equal values for chlorhexidine in free form and in nanoparticles. To verify the penetration of nanoparticles in the dentin tubules, SEM/EDS was used, through the identification of chlorine atoms, allowing the observation of nanoparticles in the interior of dentin tubules and deposited on the dentin surface. In the in vivo test using rats, it was able to observe, histologically and radiographically, the effect of the lipid nanoparticles, including when associated to calcium hydroxide, improving the antimicrobial properties of the association. These results suggest that chlorhexidine can be associated to solid lipid nanoparticles, keeping its antimicrobial effect, enabling its use as intracanal medication in dentistry, and assisting in the preservation of the drug when in association with calcium hydroxide paste to avoid their degradation by high pH value.
A medicação intracanal tem por objetivo eliminar os microrganismos presentes no interior do sistema de canais radiculares, possibilitando o reparo dos tecidos perirradiculares danificados pela ação microbiana. Apesar dos inúmeros medicamentos utilizados, ainda não existe um fármaco ideal. Assim, este estudo visa desenvolver e caracterizar nanopartículas contendo clorexidina, avaliar seu processo de degradação na associação com a pasta de hidróxido de cálcio e analisar sua eficácia através de testes in vitro e in vivo. Foram desenvolvidas e caracterizadas nanopartículas lipídicas sólidas contendo clorexidina nas concentrações de 0,2 e 0,5 %, na forma de suspensão e gel, apresentando valores de tamanho médio de partícula de 88,5 nm e 84,6 nm, respectivamente. As amostras foram armazenadas por 90 dias mantendo-se estáveis em temperatura ambiente e geladeira, porém instáveis em estufa a 40°C. O doseamento da clorexidina livre associada à pasta de hidróxido de cálcio mostrou uma redução de 33 % de fármaco após 14 dias de análise, já a clorexidina nanoencapsulada sofreu degradação de apenas 10 % do seu total. O teste de difusão em ágar frente à C. albicans e E. faecalis, pelo período de 72 h, mostrou halos de inibição de menor tamanho, porém com aumento crescente. Apesar deste resultado aparentemente desfavorável, a concentração inibitória mínima mostrou valores iguais para as nanopartículas em comparação ao fármaco livre frente aos mesmos microrganismos. Para observar a penetração das nanopartículas no interior dos túbulos dentinários foi utilizado como método de análise a microscopia eletrônica de varredura associada à energia dispersiva de raios X, através da identificação de átomos de cloro. Esta técnica permitiu observar a presença das nanopartículas no interior dos túbulos e depositadas sobre a superfície dentinária. No teste in vivo em ratos, foi possível observar, radiograficamente e histologicamente, a ação das nanopartículas lipídicas de clorexidina, inclusive da associação à pasta de hidróxido de cálcio, melhorando as propriedades microbianas da mistura. Os resultados sugerem que a clorexidina pode ser associada a nanopartículas lipídicas sólidas, mantendo a ação antimicrobiana da clorexidina, possibilitando seu uso como medicação intracanal em Odontologia e auxiliando na preservação do fármaco quando em associação com a pasta de hidróxido de cálcio evitando sua degradação pelo elevado valor de pH.

O objetivo deste trabalho foi avaliar a capacidade da solução de nanopartículas de prata, utilizada como irrigante e medicação intracanal, em controlar os microrganismos e neutralizar endotoxinas no canal radicular. Para isso, foram utilizadas 48 raízes de dentes humanos padronizadas em 16 mm e com diâmetro apical correspondente a uma lima tipo Kerr no. 30. Os canais foram contaminados por 28 dias com E. coli e por 21 dias com E. faecalis e C. albicans. Os espécimes foram divididos em quatro grupos (n=12), de acordo com a substância utilizada (solução irrigadora e medicação intracanal): G1) solução salina e solução salina (grupo controle); G2) hipoclorito de sódio 1% associado ao creme Endo-PTC e hidróxido de cálcio - protocolo tradicional da FOUSP; G3) solução de nanopartículas de prata 50 ppm e hidróxido de cálcio associado à solução de nanopartículas de prata; e G4) solução de nanopartículas de prata 50 ppm e solução de nanopartículas de prata 50 ppm. Foram realizadas cinco coletas do conteúdo do canal radicular para avaliar a atividade antimicrobiana: coleta de confirmação, imediatamente após a instrumentação (1ª. coleta) e outra após sete dias (2ª. coleta); imediatamente após a remoção da medicação (3ª. coleta) e outra após sete dias (4ª. coleta). A neutralização da endotoxina foi avaliada apenas nas quatro últimas coletas. Os resultados obtidos foram submetidos a análise estatística (Kruskall-Wallis e Dunn). Todas as soluções irrigadoras promoveram redução significativa dos microrganismos após a instrumentação (1ª. coleta) (p<0,05). Após 7 dias houve aumento do número de microrganismos em todos os grupos, voltando ao número inicial nos grupos instrumentados com solução salina e hipoclorito de sódio. Entretanto, apesar de ter ocorrido recolonização dos microrganismos no canal radicular dos espécimes instrumentados com solução de nanopartículas de prata, manteve-se redução estatisticamente significantemente do número de UFC/mL quando comparada à coleta de confirmação (p<0,05), demonstrando efeito residual. A medicação de hidróxido de cálcio eliminou 100% dos microrganismos e manteve os resultados após 7 dias (4ª. coleta) no grupo 2. No grupo quatro houve recolonização de E. faecalis e C. albicans após 7 dias de incubação. O hidróxido de cálcio foi a única substância avaliada que promoveu redução significativa (p<0,05) das endotoxinas. Assim, pôde-se concluir que o hipoclorito de sódio e a solução de NP-Ag reduziram significativamente a microbiota do canal, no entanto somente com a associação ao hidróxido de cálcio houve eliminação dos microrganismos em profundidade nos túbulos dentinários e redução das endotoxinas presentes no canal radicular.
The objective of this study was to evaluate the antimicrobial effect and endotoxin detoxified of solution of silver nanoparticles used as irrigating and dressing in root canals. Forty-eigth single-root human teeth were used. All root canals sized 16 mm and were enlarged to a Kerr file number .30. Root canals were infected for 28 days with E. coli and for 21 days with E. faecalis and C. albicans. The specimens were divided into four groups (n=12), according to the substance used (irrigating solution and dressing): G1) saline and saline (control), G2) sodium hypochlorite 1% with Endo-PTC cream and calcium hydroxide; G3) solution of Ag-NP 50 ppm and calcium hydroxide with Ag-NP; and G4) solution of Ag-NP 50 ppm and solution of Ag-NP 50 ppm. Five samplings of root canal were accomplished to evaluate the antimicrobial activity: confirmation sample, immediately after instrumentation (1st. Sample), and other after 7 days (2 nd. Sample), immediately after dressing removed (3 rd. Sample) and other after 7 days (4 th. Sample). The endotoxina detoxified was evaluated only in the last four samples by Limulus assay. Results were analysed by Kruskal-Wallis and Dunn. All irrigation solutions caused significant reduction of microorganisms after instrumentation (1 st. Collection) (p <0.05). After 7 days there was increase of the number of bacteria in all groups, returning to the initial number of microorganisms in the groups prepared with saline and sodium hypochlorite, however, the recolonization of microorganisms in root canals of groups of solution silver nanoparticles was smaller than the number of confirmation sample (p <0.05), showing residual effect. The calcium hydroxide eliminated 100% of the microorganisms and the results remained after 7 days (4 th. Collection) for group 2. In group 4 there was recolonization of E. faecalis and C. albicans after 7 days. Calcium hydroxide was the only substance that measured a significant reduction of endotoxin (p <0.05). Thus, we concluded that the sodium hypochlorite and the NP-Ag significantly reduced the microorganisms of the root canal, but it is necessary the combination of calcium hydroxide to eliminated all microorganisms into dentinal tubules and detoxified endotoxins in the root canal.

碩士
雲林科技大學
文化資產維護系碩士班
99
Nanotechnology in recent years has been widely used in the improvement of various traditional techniques, has been used internationally nanoparticles of calcium hydroxide used in wall paintings, stone carvings and other works of the reinforced soil material, but not used in ceramic matrix reinforcement of the test, this study synthesized nano particles of calcium hydroxide, and the use of isopropyl alcohol as the solvent, the size of sonication the particle size of 80 ~ 150nm dispersed colloidal solution in order to concentrate the hydrogen vacuum drying calcium oxide / isopropanol ratio was 5g / l. Use this solution as calcium hydroxide colloid agent reinforcement, reinforcement agent to neutral temperature of 50 ℃ Humidity 95% of carbon dioxide conservation, conservation of the crystal structure changes after the use of Raman spectroscopy analysis showed that calcium hydroxide did not and fetal The reaction of the body into silica, calcium silicate, calcium carbonate, just turn and for, the inference mechanism for the physical reinforcement reinforcement. Comparison of infiltration after reinforcement porosity, water absorption was reduced by approximately two percentage points, an increase of seven percentage points bending strength to prove that the reinforcement of calcium hydroxide for the matrix porosity, water absorption and bending strength have a positive effect.

Canvas has begun the favourite painting’s support of the modern age. Flax has been the natural fibre mainly used for this purpose in the centuries. One of the main conservative problem that affects natural fibres is the depolymerisation of cellulose chains. This process involves a decrease of the molecular weight of cellulose chains, that results in a drastic fall of the mechanical resistance of the fibre cell, of the yarn and the fabric as a whole. The restoration procedure more used in the centuries to overlap the structural failure of painting supports, due to depolymerisation and degradation of fibres, is the lining technique. However it represents a controversial method because of the irreversible modifications of the original painting matter that involves, due to the high temperature and pressure conditions requested by the procedure. The aim of this project was finding a material able to consolidate and restructure fibres, actually improving the mechanical characteristics of the old flax canvas and archaeological textiles, which could represent an alternative to line, at least in the less damaged cases. To reach this goal two different products has been tested as consolidant materials: Funori, an heterogeneous mixture extracted from a family of Japanese red seaweeds; a cellulose derivative synthesized by the research group of Prof. Antonella Salvini, associated professor of the “Ugo Schiff” Chemistry Department at the University of Florence; Both the products chosen for the experimentation are characterized by a similar chemical nature with the flax fibre composing canvas supports. This characteristic not only guarantees the chemical compatibility of the two consolidants with the support they will be applied on, but it also allows to suppose the establishment of chemical interactions between the products and the support. Moreover, the combined treatment with calcium hydroxide nanoparticles dispersions has been tested. The aim was to add the preservative action of alkaline earth metal hydroxide nanoparticles against acidic hydrolysis of cellulose to the consolidating action of the two products chosen for the experiment.

This work has been focused on the development and characterization of nanomaterials for restoration and conservation treatments of mural paintings in situ in different pre-Hispanic archaeological sites based in two principle lines, cleaning and consolidation. The first venture involved the cleaning of wall paintings, particularly the removal of synthetic polymers used as consolidants in restorations applied during the past few decades that have now have become a new source of deterioration. Secondly, the consolidation of the pictorial layers through the use of nanoparticles of calcium and barium hydroxide, materials highly compatible with the original substrate was investigated. The two issues were addressed by performing experimental work on samples taken from the sites and of model samples in laboratory, in order to characterize in a complete way the different materials and evaluate the applicability of intervention techniques. Based on the experimental results, different tests were conducted in situ to verify the effectiveness of the products/treatments. In particular, case studies of archaeological sites in Mexico with ongoing restoration projects were undertaken.

For the first time the possibility of the complex nanodispersed compound formation at mechanochemical and sonochemical treatment of the initial compounds mixture was shown. Mechochemical treatment of the mixture of molybdenum oxide and bismuth nitrate permits to obtain of bismuth molybdate in form of nanoparticles, in the same time the treatment of mixture of titanium oxide and calcium hydroxide leads to formation of calcium titanate in form of nanoprisms. It was shown that mechanochemical treatment of the mixture of titanium oxide and tin oxide leads to formation of titanium oxide amorphous layer on tin oxide surface. The mechanism of nanodispersed zinc molybdate formation at sonochemical treatment of initial oxides was established. It was shown that nanocomposites synthesized by these methods demonstrate the higher catalytic activity in organic compounds neutralization processes in water solutions at visible light irradiation and in the process of bioethanol selective oxidation to acetaldehyde and hydrogen in comparison with known analogous catalysts synthesized by traditional methods.