Avaliação de blendas à base de cimento de aluminato de cálcio como substitutos ósseos: estudo in vivo e microbiológico
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2018-09-28
Autores
Camporês, Kaíke Lessa [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O aluminato de cálcio (CAC) como biomaterial tem sido avaliado em relação as suas propriedades físicas, mecânicas e de biocompatibilidade, sendo que suas características únicas de endurecimento e microestrutura, o tornam um biomaterial de destaque. Estudos relataram aplicação destes cimentos na ortopedia visando neoformação óssea devido a sua composição e coeficiente de expansão térmica semelhante ao osso humano. O objetivo neste estudo foi avaliar composições de blendas à base de cimento de aluminato de cálcio homogêneo (CACH) como substitutos em defeitos ósseos. Cinco composições de blendas (alumina, fosfato tricálcico, hidroxiapatita, quitosana, zircônia), além do cimento base CACH e de polimetilmetacrilato (PMMA), totalizando 07 grupos (n=5), foram avaliados quanto à neoformação óssea e formação de biofilme. Foi realizado um defeito ósseo monocortical de 3.0 mm nos fêmures direitos de 35 ratos Wistar, que foram preenchidos aleatoriamente com os materiais acima citados, sendo o grupo de PMMA utilizado como controle. Todos os animais foram eutanasiados após 30 dias a cirurgia. Posteriormente, foi realizada análise por microtomografia computadorizada para verificação da neoformação óssea na interface osso-biomaterial. Para avaliar a formação de biofilmes microbianos monotípicos, discos padronizados com 13,0 x 2,0 mm (n=6) dos 07 cimentos foram confeccionados. Cepas de referência de Staphylococcus aureus, Streptococcus mutans e Pseudomonas aeruginosa foram cultivadas sobre as amostras e posteriormente o biofilme formado foi quantificado pelo método de MTT. O teste ANOVA foi utilizado para análise estatística e quando necessário foi aplicado o teste de comparação múltipla de Tukey (p<0,05). Nos resultados da microtomografia observou-se que em todos os parâmetros as blendas exibiram melhores resultados que o grupo controle (PMMA) sendo observada diferença estatística (p>0,05), blendas de hidroxiapatita e zircônia em geral se destacaram. Na formação de biofilmes foi observada diferença estatística (p>0,05) entre as blendas de quitosana e alumina e o grupo controle. Concluiu-se que as blendas à base de cimento de aluminato de cálcio com hidroxiapatita e zircônia são promissoras para utilização em preenchimentos de defeitos ósseos; uma vez que promovem maior neoformação óssea na interface e não alteram a formação de biofilmes microbianos monotípicos de S. aureus, S. mutans e P. aeruginosa, quando comparadas ao PMMA.
Calcium aluminate as biomaterial has been evaluated for its physical, mechanical and biocompatibility properties. Calcium aluminate based materials exhibit, due to their unique hardening and microstructure characteristics, a great potential as a biomaterial. Studies have reported the application of these cements in orthopedics aimed at bone neoformation due to its composition and coefficient of thermal expansion similar to human bone. Thus, the aim of this study is to evaluate compositions of calcium aluminate cement based blends as substitutes for bone defects. Five compositions of blends (alumina, tricalcium phosphate, hydroxyapatite, chitosan, zirconia), in addition to the base cement consisting of homogeneous calcium aluminate (CACH) and polymethylmethacrylate (PMMA) cement are being evaluated for bone repair and biofilm formation. A monocortical bone defect of 3.0 mm was performed in the right femurs of 35 Wistar rats, these were randomly filled with the already mentioned materials, and the PMMA group was used as control, totaling 07 study groups (n=5). All animals were euthanized within four weeks. Subsequently, a computerized microtomography analysis was performed to verify bone repair. To evaluate the formation of monotypic microbial biofilms, standardized discs with 13.0 x 2.0 mm (n=6) of the seven types of cements evaluated were prepared. Reference strains of Staphylococcus aureus, Streptococcus mutans and Pseudomonas aeruginosa were cultured on the samples and subsequently the biofilm formed was quantified by the MTT method. The ANOVA test was used for statistical analysis and when necessary the Tukey multiple comparison test (p <0.05) was applied. In the results of the microtomography, it was observed that in all parameters the blends exhibited better results than the control group (PMMA), with statistically significant differences (p> 0.05), hydroxyapatite blends and zirconia in general. In the biofilm formation, a statistical difference (p> 0.05) was observed between the chitosan and alumina blends and the control group. It was concluded that calcium aluminate cement-based blends with hydroxyapatite and zirconia are promising for use in bone defect fills; since they promote greater bone neoformation at the interface and do not alter the formation of monotypic microbial biofilms of S. aureus, S. mutans and P. aeruginosa when compared to PMMA.
Calcium aluminate as biomaterial has been evaluated for its physical, mechanical and biocompatibility properties. Calcium aluminate based materials exhibit, due to their unique hardening and microstructure characteristics, a great potential as a biomaterial. Studies have reported the application of these cements in orthopedics aimed at bone neoformation due to its composition and coefficient of thermal expansion similar to human bone. Thus, the aim of this study is to evaluate compositions of calcium aluminate cement based blends as substitutes for bone defects. Five compositions of blends (alumina, tricalcium phosphate, hydroxyapatite, chitosan, zirconia), in addition to the base cement consisting of homogeneous calcium aluminate (CACH) and polymethylmethacrylate (PMMA) cement are being evaluated for bone repair and biofilm formation. A monocortical bone defect of 3.0 mm was performed in the right femurs of 35 Wistar rats, these were randomly filled with the already mentioned materials, and the PMMA group was used as control, totaling 07 study groups (n=5). All animals were euthanized within four weeks. Subsequently, a computerized microtomography analysis was performed to verify bone repair. To evaluate the formation of monotypic microbial biofilms, standardized discs with 13.0 x 2.0 mm (n=6) of the seven types of cements evaluated were prepared. Reference strains of Staphylococcus aureus, Streptococcus mutans and Pseudomonas aeruginosa were cultured on the samples and subsequently the biofilm formed was quantified by the MTT method. The ANOVA test was used for statistical analysis and when necessary the Tukey multiple comparison test (p <0.05) was applied. In the results of the microtomography, it was observed that in all parameters the blends exhibited better results than the control group (PMMA), with statistically significant differences (p> 0.05), hydroxyapatite blends and zirconia in general. In the biofilm formation, a statistical difference (p> 0.05) was observed between the chitosan and alumina blends and the control group. It was concluded that calcium aluminate cement-based blends with hydroxyapatite and zirconia are promising for use in bone defect fills; since they promote greater bone neoformation at the interface and do not alter the formation of monotypic microbial biofilms of S. aureus, S. mutans and P. aeruginosa when compared to PMMA.
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Palavras-chave
Biofilmes, Cimentos para ossos, Cimento de aluminato de cálcio, Regeneração óssea, Substitutos ósseos, Biofilms, Bone cements, Bone regeneration, Bone substitutes, Calcium aluminate Cement