Comparison of Flexural Properties of Bulk-fill Restorative/Flowable Composites and Their Conventional Counterparts

Abstract

SUMMARY The objectives of the study were to compare the flexural modulus and strength of restorative and flowable bulk-fill resin-based composites (RBCs) to their conventional counterparts and to determine the effects of conditioning environment on their flexural properties. The materials evaluated included three conventional RBCs (Filtek Z350, Tetric N Ceram, and Beautifil II), three restorative bulk-fill RBCs (Filtek Bulk-Fill Restorative, Tetric N Ceram Bulk-Fill, and Beautifil Bulk-fill Restorative), as well as three flowable bulk-fill RBCs (Filtek Bulk-Fill Flowable, Tetric N Flow Bulk-Fill, and Beautifil Bulk-Fill Flowable). Specimens were fabricated using customized stainless-steel molds, finished, measured, and randomly divided into four groups. The various RBCs were conditioned in the following mediums (n=10) for seven days at 37°C: air, artificial saliva (SAGF), 0.02 N citric acid, and 50% ethanol-water solution. After conditioning, the specimens were rinsed, blotted dry, measured, and subjected to flexural testing using a universal testing machine. Data were subjected to statistical analysis using analysis of variance and the Tukey test at a significance level of α = 0.05. Significant differences in flexural properties were observed between materials and conditioning mediums. Bulk-fill restorative RBCs exhibited higher flexural modulus than their bulk-fill flowable and conventional counterparts. With the exception of Filtek Bulk-Fill Flowable, bulk-fill flowable RBCs had significantly higher flexural strength than bulk-fill restorative and conventional RBCs. Flexural properties were highest when RBCs were conditioned in air and generally the lowest after exposure to ethanol.

Effects of curing modes on depth of cure and microtensile bond strength of bulk fill composites to dentin

“…However, most recent studies report data related to the former formulation, compatible with the bulk fill composites used in our study. 5,6,39,40 In addition, our study cannot expand on further discussion related to the potential interference of the two material composition, since they were not directly compared.…”

“…3,4 Although these modifications vary, most manufacturers aim for a more translucent material with enhanced curing capability through filler modifications, 2,3 incorporation of high molecular weight monomers, and/or addition of new alternative photoinitiators. 2,[5][6][7][8] Several commercially available bulk-fill materials have increased filler size or decreased filler content to minimize the scattering of light, thus encouraging light transmittance. 2,7 Moreover, modifications to monomers and photoinitiator targets improved optical properties, reduced polymerization shrinkage, and increased DOC.…”

Efficacy of Bulk Fill Flowable Composite Reinforced with Short Fibers in Fracture Resistance of Restored Extensive Premolars Cavities

“…Therefore, they recommended SFRC in high stressbearing areas for its enhanced toughness. (24,25) Restorable fracture was 80% for teeth restored with bulk fill flowable composite that is comparable to negative control group (sound non cavitated teeth),this is attributed to the evolution that made the bulk fill flow composites more flexural strength, more flow and less shrinkage with less cuspal strains as stated by authors about bulk fill flow composite (26,27) The increase in non restorable fracture in teeth restored with SFRC(everX flow) compared to teeth filled with bulk fill flow(Tetric N flow) restorations could be due to the thicker consistency of SFRC due to the added short fibers, impairing bonding resistance and favoring breakdown of the adhesive interface. (12)…”

Grau de conversão, propriedades ópticas e mecânicas de resinas compostas bulk-fill em função de dois aparelhos fotopolimerizadores e de tratamento térmico

“…Assim, uma maior dose de luz é transmitida até a base das restaurações 101 . Comumente utilizada 10,20,25,59,90,[102][103][104][105][106] , a resistência à flexão representa a tensão experimentada por um material no momento da sua ruptura 25,95 e está diretamente relacionada à dureza e ao módulo de elasticidade 107,108 , além do conteúdo de carga 19,36,44,102,106,109 devido ao fato de que a adesão entre a matriz orgânica e a fase inorgânica permite a transferência da tensão gerada da matriz polimérica para as partículas de carga 19 . Variáveis como conteúdo da matriz resinosa 19,110 , protocolo de fotoativação 96,106 , grau de conversão 111 , quantidade de monômeros não reagidos 37 e tratamentos de cura pós-fotoativação 37,104,105,112,113…”

“…Sendo assim, a nanodureza permite a obtenção da resposta do material a partir da deformação plástica em profundidade e não apenas a partir da profundidade final da endentação83 . Através do mesmo teste de nanoendentação, é possível a obtenção do módulo de elasticidade86,94 , que descreve a rigidez do material83,95 .…”