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Resistência à flexão e microdureza : resinas compostas Bulk-Fill vs resinas compostas universais
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Objetivo: Comparar as propriedades mecânicas de duas resinas compostas SimpliShade Bulk-Fill e SimpliShade Universal da marca Kerr através da avaliação da microdureza de superfície e da resistência à flexão. Materiais e Métodos: Foram preparados 20 espécimes, sob a forma de palito (n = 10 por grupo), com a dimensão 2 × 2 × 25 mm, segundo a norma ISO 4049. As amostras foram submetidas a dois ensaios mecânicos: teste de microdureza de Vickers (carga de 980,7mN durante 15 s) e teste de resistência à flexão em três pontos (velocidade média de 0,5 mm/min até à fratura do espécime), utilizando uma máquina de teste universal. Os dados foram analisados estatisticamente através do teste t para amostras independentes (p > 0,05) e cálculo do tamanho do efeito (Cohen’s d). Resultados: A resina composta Bulk-Fill apresentou uma microdureza significativamente superior (55,95 ± 3,13 HV) em comparação com a resina composta Universal (47,65 ± 2,36 HV), com p < 0,001. O tamanho do efeito foi elevado (Cohen’s d = 2,77), indicando uma magnitude considerável da diferença entre os grupos. Relativamente à resistência à flexão, a média do grupo Universal foi ligeiramente superior (165,16 ± 19,77 MPa) à do grupo Bulk-Fill (154,78 ± 21,61 MPa), mas esta diferença não foi estatisticamente significativa (p = 0,277). O tamanho do efeito foi moderado (Cohen’s d = 0,50). Conclusão: A resina Bulk-Fill demonstrou uma microdureza superior, sugerindo maior resistência ao desgaste. Não foram encontradas diferenças estatisticamente significativas na resistência à flexão, o que indica um comportamento mecânico comparável entre os dois materiais. Os resultados obtidos estão parcialmente de acordo com estudos prévios e indicam que ambos os compósitos podem ser clinicamente viáveis. Estudos futuros devem incluir amostras maiores, envelhecimento artificial e avaliação de propriedades adicionais.
To compare the mechanical properties of two resin composites, SimpliShade Bulk-Fill and SimpliShade Universal from Kerr, through the evaluation of surface microhardness and flexural strength. Materials and Methods: Twenty stick-shaped specimens (n = 10 per group), measuring 2 × 2 × 25 mm, were prepared according to ISO 4049. The samples were subjected to two mechanical tests: the Vickers microhardness test (980.7 mN load for 15 seconds) and the three-point flexural strength test (crosshead speed of 0.5 mm/min until specimen fracture), performed using a universal testing machine. The data were analyzed statistically using independent sample t-tests (p > 0.05), and the effect size was calculated using Cohen’s d. Results: The Bulk-Fill resin composite exhibited significantly higher microhardness (55.95 ± 3.13 HV) compared to the Universal resin composite (47.65 ± 2.36 HV), with a p-value < 0.001. The effect size was large (Cohen’s d = 2.77), indicating a substantial difference between the groups. In terms of flexural strength, the Universal group showed a slightly higher mean value (165.16 ± 19.77 MPa) than the Bulk-Fill group (154.78 ± 21.61 MPa), but this difference was not statistically significant (p = 0.277). The effect size was moderate (Cohen’s d = 0.50). Conclusion: The Bulk-Fill resin demonstrated superior microhardness, suggesting greater resistance to surface wear. No statistically significant differences were observed in flexural strength, indicating a comparable mechanical performance between the two materials. The results are partially consistent with previous studies and support the potential clinical use of both composites. Future studies should include larger sample sizes, artificial aging protocols, and the assessment of additional biomechanical properties.
To compare the mechanical properties of two resin composites, SimpliShade Bulk-Fill and SimpliShade Universal from Kerr, through the evaluation of surface microhardness and flexural strength. Materials and Methods: Twenty stick-shaped specimens (n = 10 per group), measuring 2 × 2 × 25 mm, were prepared according to ISO 4049. The samples were subjected to two mechanical tests: the Vickers microhardness test (980.7 mN load for 15 seconds) and the three-point flexural strength test (crosshead speed of 0.5 mm/min until specimen fracture), performed using a universal testing machine. The data were analyzed statistically using independent sample t-tests (p > 0.05), and the effect size was calculated using Cohen’s d. Results: The Bulk-Fill resin composite exhibited significantly higher microhardness (55.95 ± 3.13 HV) compared to the Universal resin composite (47.65 ± 2.36 HV), with a p-value < 0.001. The effect size was large (Cohen’s d = 2.77), indicating a substantial difference between the groups. In terms of flexural strength, the Universal group showed a slightly higher mean value (165.16 ± 19.77 MPa) than the Bulk-Fill group (154.78 ± 21.61 MPa), but this difference was not statistically significant (p = 0.277). The effect size was moderate (Cohen’s d = 0.50). Conclusion: The Bulk-Fill resin demonstrated superior microhardness, suggesting greater resistance to surface wear. No statistically significant differences were observed in flexural strength, indicating a comparable mechanical performance between the two materials. The results are partially consistent with previous studies and support the potential clinical use of both composites. Future studies should include larger sample sizes, artificial aging protocols, and the assessment of additional biomechanical properties.
Descrição
Dissertação de Mestrado Integrado em Medicina Dentária, 2025
Palavras-chave
resinas compostas resina composta Bulk-Fill resina composta universal resistência à flexão resin composites Bulk-Fill composite universal composite microhardness flexural strength