Análisis de la distribución de microdureza, contenido mineral y orgánico de dientes humanos, bovinos y ovinos

Objetive. Human teeth have been commonly used for in vitro and in situ studies. Cu­rrently, other animals’ teeth have been purposed for dental research to overcome human teeth’ problematic availability. This study aimed to investigate the enamel and dentin from human, bovine, and ovine teeth concerning the microhardness, organic, and inorganic contents via micro-Raman spectroscopy. Methods. Human, bovine, and ovine teeth were divided according to their type and age into seven groups: Ovine; Bovine-12 months; Bovine-24 months; Bovine-36 months; Bovine-48 months; Bovine-+60 months; Human (control). The enamel’s microhardness (superficial and deep) and dentin (superficial, middle, and deep) were analyzed. The calcium/phosphate ratio and amide contents were determined by micro-Raman spectroscopy. Results. Overall, the microhardness of human enamel was superior to the other species. Dentin’s microhardness was similar among groups. Ovine group showed lower values of calcium/phosphate ratio than human. Amide content was similar between bovine and human. The microhardness and calcium/phosphate ratio of enamel and dentin, respectively, decreased as the age of bovine teeth increased. Conclusions. Researchers must be aware and take into consideration the differences of ovine and bovine enamel compared to human enamel. Other alternatives that are more similar to the microhardness of human enamel should be sought. Bovine teeth of 12 and 24 months are suitable substitutes for dentin of human teeth. Researchers must also be aware of the age of the animals and specify it in the studies.Objetivo. Los dientes humanos se han utilizado comúnmente para estudios in vitro e in situ. Actualmente, los dientes de otros animales se han destinado a la investigación dental para superar la disponibilidad problemática de los dientes humanos. Este estudio tuvo como objetivo investigar el esmalte y la dentina de los dientes humanos, bovinos y ovinos en relación con la microdureza y los contenidos orgánicos e inorgánicos a través de la espectroscopia micro-Raman. Métodos. Los dientes humanos, bovinos y ovinos se dividieron según su tipo y edad en siete grupos: Ovinos; Bovino-12 meses; Bovino-24 meses; Bovino-36 meses; Bovino-48 meses; Bovino-+60 meses; Humano (control). Se analizó la microdureza del esmalte (superficial y profunda) y de la dentina (superficial, media y profunda). La relación calcio/fosfato y los contenidos de amida se determinaron mediante espectroscopía micro-Raman. Resultados. En general, la microdureza del esmalte humano fue superior a la de otras especies. La microdureza de la dentina fue similar entre los grupos. El grupo ovino mostró valores más bajos de la relación calcio/fosfato que el humano. El contenido de amida fue similar entre bovinos y humanos. La microdureza y la relación calcio/fosfato del esmalte y la dentina, respectivamente, disminuyeron a medida que aumentaba la edad de los dientes bovinos. Conclusiones. El esmalte de los dientes ovinos y bovinos no es un sustituto adecuado del de los dientes humanos. Se deben buscar otras alternativas que sean similares a la microdureza del esmalte humano. Sin embargo, los dientes bovinos de 12 y 24 meses son sustitutos adecuados de la dentina de los dientes humanos. Los investigadores deben conocer la edad de los animales y especificarla en los estudios

Bismuth subsalicylate as filler particle for an experimental epoxy-based root canal sealer

Aim: To evaluate the influence of bismuth subsalicylate addition in different concentrations on theproperties ofan experimental epoxy-based root canal sealer. Methods: Bismuth subsalicylate in 20%, 40%, 60%, 80%, 100% and 120 wt% was added tothe sealer. Flow, film thickness, working time, setting time, dimensional change, sorption, solubility and cytotoxicity were evaluated according to ISO standard. Data were statistically analyzed by one-way ANOVA and Tukey’stest with a significance level of 5% for all tests. Results: The flow, working and setting times significantly decreased withincreasing particle concentration. The film thickness, dimensional change, water sorption and solubility values significantly increased with higher particle amount. The results for cytotoxicity showed no statistically significant differences among the particle proportions. Conclusions: The results suggest that the addition up to 80% wt of bismuth subsalicylate appears to be a promising filler particle to root canal sealer development

Desempenho de sistemas endodônticos rotatórios constante e progressivo no preparo do canal radicular

Objective The aim of this study was to compare the performance of two nickel-titanium rotary systems regarding the preparation time, final shape of canal, incidence of aberration, transportation, and fracture of instrument. Methods A total of 40 simulated canals in resin blocks with 30o curves and a length of 17 mm were divided randomly into two groups: preparation with ProTaper and BioRaCe systems up to F5 and BR5 respectively. Pre- and post-operative canal images were taken and superimposed in order to identify aberrations, transportation, and to take measurements of the canal width. In addition, the preparation time and instrument fractures were recorded. The data were analyzed using Student's t test. Results There is no difference (p>.05) comparing the systems regarding preparation time, canal aberration, and instrument fracture rates. The progressive tapered instruments of ProTaper prepared significantly larger canal widths in the apical third (p0,05). Os instrumentos progressivos do ProTaper resultou em canais significativamente mais largos no terço apical (p<0,05). Conclusão Os dois sistemas rotatórios avaliados resultaram em preparo endodôntico seguro, com poucas alterações e fratura de instrumento

Incorporation of amoxicillin-loaded microspheres in mineral trioxide aggregate cement: an <i>in vitro</i> study.

Objectives: In this study, we investigated the potential of amoxicillin-loaded polymeric microspheres to be delivered to tooth root infection sites via a bioactive reparative cement.Materials and methods: Amoxicillin-loaded microspheres were synthesized by a spray-dray method and incorporated at 2.5% and 5% into a mineral trioxide aggregate cement clinically used to induce a mineralized barrier at the root tip of young permanent teeth with incomplete root development and necrotic pulp. The formulations were modified in liquid:powder ratios and in composition by the microspheres. The optimized formulations were evaluated in vitro for physical and mechanical eligibility. The morphology of microspheres was observed under scanning electron microscopy.Results: The optimized cement formulation containing microspheres at 5% exhibited a delayed-release response and maintained its fundamental functional properties. When mixed with amoxicillin-loaded microspheres, the setting times of both test materials significantly increased. The diametral tensile strength of cement containing microspheres at 5% was similar to control. However, phytic acid had no effect on this outcome (p > 0.05). When mixed with modified liquid:powder ratio, the setting time was significantly longer than that original liquid:powder ratio (p Conclusions: Lack of optimal concentrations of antibiotics at anatomical sites of the dental tissues is a hallmark of recurrent endodontic infections. Therefore, targeting the controlled release of broad-spectrum antibiotics may improve the therapeutic outcomes of current treatments. Overall, these results indicate that the carry of amoxicillin by microspheres could provide an alternative strategy for the local delivery of antibiotics for the management of tooth infections

Analysis of final form, fracture of instrument and time of preparation in simulated canals instrumented with two rotary systems: ProTaper Universal and BioRaCe

O estudo teve por objetivo comparar o preparo de canais simulados curvos dado pelos sistemas rotatórios ProTaper e BioRaCe em relação à análise da forma final, fratura de instrumento e tempo de preparo. Quarenta blocos de canais simulados, inicialmente identificados e fotografados, foram utilizados. Esses blocos foram divididos aleatoriamente em dois grupos; um grupo foi preparado com instrumentos do sistema ProTaper e, o outro, com o BioRaCe. Entre cada instrumento, os canais foram irrigados com 0,5 mL de água destilada e o comprimento de trabalho foi recapitulado com lima n°10 K file. A cada instrumento utilizado, foi obtida uma nova imagem de cada um dos blocos. As imagens pré e pós-operatórias foram sobrepostas para avaliar mensurações e aberrações dos canais. Além disso, o tempo de preparo e fratura de instrumento foram avaliados. Os dados foram comparados com o teste t de Student e teste exato de Fisher. O sistema BioRaCe resultou em preparo com maior ampliação do terço apical (p<.01) com menor média de tempo (p<.01) ao ser comparado com o sistema ProTaper. O sistema BioRaCe apresentou mesmo desempenho quanto à resistência à fratura do instrumento e iatrogenias inerentes ao preparo ao ser comparado ao sistema ProTaper. Quanto ao tempo de trabalho, o sistema BioRaCe realizou o preparo de maneira mais rápida que o sistema ProTaper, realizando maior ampliação do terço apical. Portanto, os dois sistemas são seguros, em relação a fratura de instrumento e deformações do canal, sendo o BioRaCe mais eficiente em termos de tempo de trabalho e ampliação do terço apical.The aim of this study was to compare the preparation of simulated curved canals given by ProTaper and BioRaCe with the analysis of the final form, fracture of instrument and time of preparation. A total of 40 blocks of simulated canals were initially identified and photographed. These blocks were divided randomly into two groups: one group was prepared with ProTaper instruments and the other with the BioRaCe. Between each instrument, the canals were irrigated with 0.5 mL of distilled water and the working length was recapitulated with no. 10 K file. After each one instrument, a new image was obtained from the blocks. The pre and postoperative images were superimposed to analyze aberrations and measurements of the canals. Moreover, the time of preparation and fracture of instrument were evaluated. Data were compared with Student's t test and Fisher's exact test. The BioRaCe system resulted in a preparation with higher magnification of the apical third (p <.01) with the lower mean time (p <.01) compared with the ProTaper system. The BioRaCe system presented same iatrogenic complications and instrument fracture resistance compared with the ProTaper system, but the BioRaCe system made the preparation faster than the ProTaper system, making higher magnification of the apical third. Therefore, both systems are secure in relation to instrument fracture and aberration of the canal, but the BioRaCe system is more efficient in terms of working time and magnification of the apical third than the ProTaper system

Dental adhesive system containing drugs-loaded nanocapsules

O objetivo da presente tese foi desenvolver um adesivo com nanocápsulas (NCs), contendo indometacina, e um sistema adesivo com nanocápsulas (NC), contendo indometacina e triclosan, e avaliar suas propriedades. As NCs foram produzidas por meio do método de deposição de polímero, secas e caracterizadas quanto ao tamanho de partículas, à forma, quantidade de fármaco encapsulado e citotoxicidade. Uma resina adesiva foi formulada. Foram adicionadas ao adesivo 1%, 2%, 5% e 10% de NCs em massa, e um grupo permaneceu sem NC. As NCs, contendo indometacina e triclosan, foram também incorporadas no primer comercial a 2% em peso e um grupo permaneceu sem NCs. Os adesivos foram avaliados quanto ao GC imediato e tardio, à degradação em solvente, liberação dos fármacos, difusão de indometacina pela dentina e resistência de união. O adesivo com 10% de NCs, contendo indometacina, foi também avaliado quanto à ação anti-inflamatória em modelo animal. O primer e o adesivo com as diferentes concentrações de NCs, contendo indometacina e triclosan, foram avaliados quanto à liberação dos fármacos, difusão de indometacina pela dentina, ao efeito antimicrobiano, grau de conversão (GC) in situ, ângulo de contato e à resistência de união à microtração. Os dados foram analisados por ANOVA, Tukey e teste t. As NCs apresentaram forma esférica e viabilidade celular acima de 80%. As NCs, contendo indometacina, apresentaram diâmetro médio de 165 nm e as NCs, contendo indometacina e triclosan, 159 nm. O adesivo, contendo 10% de NCs com indometacina, apresentou efeito anti-inflamatório. A incorporação de NCs não alterou o GC, que variou de 63,63 ± 1,01% a 70,50 ± 2,08%. A degradação em solvente não foi alterada com 2% de NCs. Tanto os adesivos quanto o primer apresentaram liberação controlada. A indometacina permeou através da dentina. O adesivo e primer também apresentaram efeito antimicrobiano. A incorporação de NCs no primer e no adesivo não influenciou o GC in situ nem a resistência de união imediata, em comparação aos materiais sem NCs. O uso concomitante do primer e adesivo com NCs aumentou o ângulo de contato e diminuiu a resistência de união longitudinal. Conclui-se que o uso do adesivo com a incorporação de NCs tem potencial para proporcionar ações terapêuticas à adesão dentinária.The aim of the present thesis was to develop an adhesive with nanocapsules (NCs) containing indomethacin and an adhesive system with nanocapsules containing indomethacin and triclosan and to evaluate their properties. NCs were prepared by the interfacial deposition of preformed polymer technique, dried and characterized regarding particle size, encapsulated drug content and cytotoxicity. Adhesive resin was produced. Concentrations of 1%, 2%, 5% and 10% of NCs were added in the adhesive and a group was maintained with no NCs. Indomethacin and triclosan-loaded NCs were also incorporated into a commercial primer in a concentration of 2% and a group was maintained with no NCs. Adhesives were evaluated regarding immediate and late degree of conversion (DC), degradation in solvent, drug release, indomethacin diffusion through dentin and bond strength. The adhesive with 10% of NCs containing indomethacin was also evaluated regarding the anti-inflammatory effect in an animal model. Primer and adhesive with different concentrations of NCs containing indomethacin and triclosan were evaluated regarding drug release, indomethacin diffusion through dentin, antimicrobial effect, in situ degree of conversion, contact angle and bond strength. Data were analyzed through ANOVA, Tukey post-hoc and t-test.NCs presented a spherical shape and cell viability higher than 80%. NCs containing indomethacin presented an averaged size of 165 nm and NCs containing indomethacin and triclosan, 159 nm. The adhesive with 10% of NCs containing indomethacin presented anti-inflammatory effect. The incorporation of NCs presented no alteration of DC, varying from 63.63 ± 1.01% a 70.50 ± 2.08%. Degradation in solvent suffers no influence of NCs with 2% of NCs. Adhesives and primer presented controlled drug release. Indomethacin diffused through dentin. Adhesive and primer also presented an antimicrobial effect. The incorporation of NCs in adhesive and primer showed no influence on in situ DC and immediate bond strength compared to materials with no NCs. The use in combination of primer and adhesive with NCs resulted in higher contact angle and lower longitudinal bond strength. It is possible to conclude that the use adhesive with incorporation of NCs has potential to provide therapeutic effects on dentin adhesion