Resumen de Estudio comparativo de la composición y estructura cristalina del esmalte y dentina humano, bovino, ovino y de cerdo
- español
Introducción. Los dientes humanos son los candidatos ideales para la realización de los estudios experimentales in vitro. Sin embargo su uso de los dientes humanos encuentra muchas limitaciones: son muy difíciles de obtener con suficiente calidad y cantidad, es difícil establecer una muestra homogénea debido a la dificultad de control de la edad y del origen del diente. Por ello se hace necesario el estudio de otros sustratos alternativos. El objetivo de nuestra investigación fue estudiar la composición química y las diferencias entre las nanoestructuras cristalinas del esmalte y dentina humanos y las especies bovina, porcina y ovina, que son los candidatos para sustituirlos en los estudios experimentales.
Material y métodos. En este estudio se escogieron fragmentos de esmalte y dentina de 400 dientes sanos humanos, bovinos, ovinos y porcinos. Estos fueron triturados hasta conseguir una partícula menor de 100 m de tamaño. Para hallar su composición química se usaron el Análisis Elemental (C/N), la Termogravimetría unida a Espectrometría de Masas (TG-MS) y la Espectrometría de Fluorescencia de Rayos X por dispersión de longitud de onda (XRF). Para estudiar la estructura cristalina se usó la difracción de Rayos X (XRD), la Espectrometría infrarroja transformada de Fourier (FTIR) y la Calorimetría diferencial de barrido (DSC).
Resultados. El C/N mostró más cantidad de carbón orgánico y nitrógeno en dentina que en esmalte. El esmalte humano fue la muestra más mineralizada de todas, con unos valores de C y N cercanos a la Hidroxiapatita (HA). El esmalte y la dentina bovina fueron los más parecidos al humano. El TG-MS, para todas las especies, mostró que el esmalte contenía menos carbón y materia orgánica que la dentina. La descomposición térmica para el esmalte humano mostró gran similitud con la Hidroxiapatita Sintética (HAS), y grandes diferencias con el esmalte bovino, ovino y porcino. Esta descomposición térmica mostró una gran similitud entre la dentina bovina y humana. Con XRF se encontró que la dentina contenía mayores cantidades de Mg, S, Sr y Zn que el esmalte. El esmalte contenía mayores cantidades de P, Ca, Cl, Cu, K y relación Ca/P que la dentina. El esmalte y la dentina humana contenían mayor relación Ca/P, mayores cantidades de Cl y Cu, y menores cantidades de Mg, S y Zn que el resto de especies animales. Con XRD, la HAs de los esmaltes obtuvieron mayores índices de cristalinidad (IC) ICRietveld que las dentinas de la misma especie. Esmalte y dentina humanos mostraron el IC más alto, seguido de esmalte y dentina ovinos. Con FTIR, los tamaños de los cristales y el ICFTIR del esmalte fueron siempre mayores que en dentinas para todas las especies. El major ICFTIR fue encontrado para el esmalte humano y el ovino. De acuerdo con DSC, el diente porcino mostró el salto más parecido al diente humano durante el proceso de Transición Vítrea (?Cp).
Para conocer entre todos los sustratos cuál es el más parecido al sustrato ideal (el diente humano) hemos usado un Método de Toma de Decisiones Multicriterio (MCDM). Exáctamente, el Proceso Analítico Jerárquico (AHP) y el Método de Referencia Ideal (RIM).
Conclusiones. C/N, TG-MS y XRF mostraron que el esmalte y dentina bovinos muestran las mayores similitudes al humano de entre todas las muestras analizadas. En estudios donde las propiedades mecánicas o fisicoquímicas del esmalte o la dentina prevalezcan, el diente ovino debería ser usado como sustituto del diente humano. Pero en los estudios donde sea más relevante el comportamiento térmico en atmosfera inerte, el diente porcino debería sustituir al humano. El MCDM indicó que, entre las especies estudiadas, el esmalte y dentina bovinos son los mas parecidos al esmalte y dentina humanos.
Introduction. Human teeth are ideal candidates for conducting in vitro experimental studies. However, their use has many limitations: they are very difficult to obtain with sufficient quality and quantity; it is difficult to establish a homogeneous sample due to the difficulty of controlling the age and origin of the tooth. Therefore, it is necessary to study other alternative substrates. The aim of this research was to study the chemical composition and the differences between the crystalline nanostructures from enamel and dentin of human, bovine, porcine, and ovine species, that are likely candidates for replacing them in studies that test dental material.
Material and Methods. Dentine and enamel fragments extracted from 400 sound human, bovine, porcine and ovine - 100 teeth per species - incisors and molars were mechanically ground up to a final particle size of less than 100 mm. Elemental analysis (C/N), thermogravimetric analysis coupled to mass spectrometry (TG-MS), and wavelength dispersive X-ray fluorescence (XRF) were used to analyse the samples' composition. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) were used to analyse the crystalline nanostructures.
Results. Elemental analysis showed more organic carbon and nitrogen in dentine than in enamel. Human enamel was the most highly mineralised, with C and N values close to hydroxyapatite. Bovine dentine and enamel were the most similar to human. TG-MS: in all species, enamel contained less carbon and organic matter than dentine. Thermal decomposition of human enamel showed great similarity to synthetic hydroxyapatite, and large differences from bovine, ovine and porcine enamel. Thermal decomposition showed the greatest similarity between human and bovine dentine. WDXRF: Dentine contained larger quantities of Mg, S, Sr and Zn than enamel. Enamel contained larger quantities of P, Ca, Cl, Cu, K and Ca/P ratio than dentine. Human enamel and dentine contained a higher Ca/P ratio, larger quantities of Cl and Cu and lower quantities of Mg, S, Zn than the animal species. Hydroxyapatites (HA) in enamel obtained higher crystallinity index (CI)Rietveld than the corresponding dentin of the same species. Human dentin (HD) and human enamel (HE) showed the highest CI, followed by ovine enamel (OE) and ovine dentin (OD). CIFTIR, and enamel crystal sizes were always higher than those of dentin for all species. The greatest CIFTIR were found for HE and OE. The most similar change in heat capacity during the glass transition (?Cp) values to human teeth, were obtained by porcine specimens.
To know among all substrates which is closest to the ideal substrate (human tooth), we have used a Multicriterial Decision Making Method (MCDM). Exactly, the Analytical Hierarchic Process (AHP) and the Reference Ideal Method (RIM).
Conclusions: C/N, TG-MS and WDXRF have shown that human and bovine enamel and dentine show the greatest similarity among the species analysed. In researches where the physicochemical and mechanical properties of enamel or dentin prevail, ovine teeth should be used as a substitute to human teeth. Where the thermal behavior in an inert atmosphere is more relevant, porcine samples should substitute human teeth. The MDCD indicated that enamel and dentin bovine are the most similar to enamel and dentin human.
- English
Introduction. Human teeth are ideal candidates for conducting in vitro experimental studies. However, their use has many limitations: they are very difficult to obtain with sufficient quality and quantity; it is difficult to establish a homogeneous sample due to the difficulty of controlling the age and origin of the tooth. Therefore, it is necessary to study other alternative substrates. The aim of this research was to study the chemical composition and the differences between the crystalline nanostructures from enamel and dentin of human, bovine, porcine, and ovine species, that are likely candidates for replacing them in studies that test dental material.
Material and Methods. Dentine and enamel fragments extracted from 400 sound human, bovine, porcine and ovine - 100 teeth per species - incisors and molars were mechanically ground up to a final particle size of less than 100 mm. Elemental analysis (C/N), thermogravimetric analysis coupled to mass spectrometry (TG-MS), and wavelength dispersive X-ray fluorescence (XRF) were used to analyse the samples' composition. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) were used to analyse the crystalline nanostructures.
Results. Elemental analysis showed more organic carbon and nitrogen in dentine than in enamel. Human enamel was the most highly mineralised, with C and N values close to hydroxyapatite. Bovine dentine and enamel were the most similar to human. TG-MS: in all species, enamel contained less carbon and organic matter than dentine. Thermal decomposition of human enamel showed great similarity to synthetic hydroxyapatite, and large differences from bovine, ovine and porcine enamel. Thermal decomposition showed the greatest similarity between human and bovine dentine. WDXRF: Dentine contained larger quantities of Mg, S, Sr and Zn than enamel. Enamel contained larger quantities of P, Ca, Cl, Cu, K and Ca/P ratio than dentine. Human enamel and dentine contained a higher Ca/P ratio, larger quantities of Cl and Cu and lower quantities of Mg, S, Zn than the animal species. Hydroxyapatites (HA) in enamel obtained higher crystallinity index (CI)Rietveld than the corresponding dentin of the same species. Human dentin (HD) and human enamel (HE) showed the highest CI, followed by ovine enamel (OE) and ovine dentin (OD). CIFTIR, and enamel crystal sizes were always higher than those of dentin for all species. The greatest CIFTIR were found for HE and OE. The most similar change in heat capacity during the glass transition (?Cp) values to human teeth, were obtained by porcine specimens.
To know among all substrates which is closest to the ideal substrate (human tooth), we have used a Multicriterial Decision Making Method (MCDM). Exactly, the Analytical Hierarchic Process (AHP) and the Reference Ideal Method (RIM).
Conclusions: C/N, TG-MS and WDXRF have shown that human and bovine enamel and dentine show the greatest similarity among the species analysed. In researches where the physicochemical and mechanical properties of enamel or dentin prevail, ovine teeth should be used as a substitute to human teeth. Where the thermal behavior in an inert atmosphere is more relevant, porcine samples should substitute human teeth. The MDCD indicated that enamel and dentin bovine are the most similar to enamel and dentin human.
