ABSTRACT
This study aimed to evaluate the microstructure formed after the chemical treatment of teeth, for the development of autogenous grafts from the demineralized dentin matrix (DDM) technique, in order to identify the most efficient demineralizing solution. The specimens, originating from the root and coronal portion, were submitted to ultrasonic cleaning and drying in an oven for 1h at 100 ºC. Then, the density was determined by Archimedes' principle for each specimen, using distilled water as immersion liquid. The samples were separated into five groups: Control group: negative control, Distilled water;EDTA group: positive control, trisodium EDTA; NaOCl group: 2.5% sodium hypochlorite; HCl-0.6M group: 0.6M hydrochloric acid; and H2O2/H2SO4 group: hydrogen peroxide and sulfuric acid. Each specimen was immersed for 1h in the corresponding group descaling solution at 60 ºC. Subsequently, the mass loss and density of the treated specimens were determined by Archimedes' principle. Ultimately, the specimens of each group were characterized by microtomography, Scanning Electron Microscopy, and Energy Dispersive Spectrometry X-ray (SEM-EDS). The results demonstrated that the H2O2/H2SO4 solution allowed the formation of interconnected micropores, suggesting better pore structures for application in scaffolds, when compared to the other studied solutions.
Subject(s)
Hydrogen Peroxide , Root Canal Irrigants , Edetic Acid/analysis , Sodium Hypochlorite , Dentin/chemistry , Water , Microscopy, Electron, Scanning , Dental Pulp CavityABSTRACT
Abstract This study aimed to evaluate the microstructure formed after the chemical treatment of teeth, for the development of autogenous grafts from the demineralized dentin matrix (DDM) technique, in order to identify the most efficient demineralizing solution. The specimens, originating from the root and coronal portion, were submitted to ultrasonic cleaning and drying in an oven for 1h at 100 ºC. Then, the density was determined by Archimedes' principle for each specimen, using distilled water as immersion liquid. The samples were separated into five groups: Control group: negative control, Distilled water;EDTA group: positive control, trisodium EDTA; NaOCl group: 2.5% sodium hypochlorite; HCl-0.6M group: 0.6M hydrochloric acid; and H2O2/H2SO4 group: hydrogen peroxide and sulfuric acid. Each specimen was immersed for 1h in the corresponding group descaling solution at 60 ºC. Subsequently, the mass loss and density of the treated specimens were determined by Archimedes' principle. Ultimately, the specimens of each group were characterized by microtomography, Scanning Electron Microscopy, and Energy Dispersive Spectrometry X-ray (SEM-EDS). The results demonstrated that the H2O2/H2SO4 solution allowed the formation of interconnected micropores, suggesting better pore structures for application in scaffolds, when compared to the other studied solutions.
Resumo Este estudo teve como objetivo avaliar a microestrutura formada após o tratamento químico em dentes, para o desenvolvimento de enxertos autógenos a partir da técnica de matriz de dentina desmineralizada (DDM), a fim de identificar a solução desmineralizante mais eficiente. Os espécimes, provenientes da raiz e porção coronal, foram submetidos à limpeza ultrassônica e secagem em estufa por 1h a 100 ºC. Em seguida, a densidade foi determinada pelo princípio de Arquimedes para cada espécime, utilizando água destilada como líquido de imersão. As amostras foram separadas em cinco grupos: Controle: controle negativo, Água destilada; EDTA: controle positivo, EDTA trissódico; NaOCl: hipoclorito de sódio 2,5%; HCl-0.6M: ácido clorídrico 0,6M; e H2O2/H2SO4: peróxido de hidrogênio e ácido sulfúrico. Cada espécime foi imerso por 1h na solução descalcificante de grupo correspondente a 60 ºC. Posteriormente, a perda de massa e a densidade dos espécimes tratados foram determinadas pelo princípio de Arquimedes. Por fim, os espécimes de cada grupo foram caracterizados por microtomografia, microscopia eletrônica de varredura e espectrometria de energia dispersiva de raios-X (SEM-EDS). Os resultados demonstraram que a solução H2O2/H2SO4 permitiu a formação de microporos interligados, sugerindo melhores estruturas de poros para aplicação em scaffolds, quando comparada às demais soluções estudadas.
ABSTRACT
In order to support bone tissue regeneration, porous biomaterial implants (scaffolds) must offer chemical and mechanical properties, besides favorable fluid transport. Titanium implants provide these requirements, and depending on their microstructural parameters, the osteointegration process can be stimulated. The pore structure of scaffolds plays an essential role in this process, guiding fluid transport for neo-bone regeneration. The objective of this work was to analyze geometric and morphologic parameters of the porous microstructure of implants and analyze their influences in the bone regeneration process, and then discuss which parameters are the most fundamental. Bone ingrowths into two different sorts of porous titanium implants were analyzed after 7, 14, 21, 28, and 35 incubation days in experimental animal models. Measurements were accomplished with x-ray microtomography image analysis from rabbit tibiae, applying a pore-network technique. Taking into account the most favorable pore sizes for neo-bone regeneration, a novel approach was employed to assess the influence of the pore structure on this process: the analyses were carried out considering minimum pore and connection sizes. With this technique, pores and connections were analyzed separately and the influence of connectivity was deeply evaluated. This investigation showed a considerable influence of the size of connections on the permeability parameter and consequently on the neo-bone regeneration. The results indicate that the processing of porous scaffolds must be focused on deliver pore connections that stimulate the transport of fluids throughout the implant to be applied as a bone replacer.
