Open AccessLow- and high-viscosity bulk-fill resin composites: a comparison of microhardness, microtensile bond strength, and fracture strength in restored molars
Author(s) -
Fabiana Mg França,
Jonathan Gb Tenuti,
Isabela P Broglio,
Lara Ej Paiva,
Roberta Tarkany Basting,
Cecília Pedroso Turssi,
F.L.B. Amaral,
André Figueiredo Reis,
Waldemir Francisco Vieira-Júnior
Publication year - 2021
Publication title -
acta odontológica latinoamericana/acta odontológica latinoamericana
Language(s) - English
Resource type - Journals
eISSN - 1852-4834
pISSN - 0326-4815
DOI - 10.54589/aol.34/2/173
Subject(s) - molar , materials science , composite material , viscosity , dentin , knoop hardness test , bond strength , indentation hardness , universal testing machine , adhesive , dentistry , ultimate tensile strength , microstructure , medicine , layer (electronics)
The aim of this study was to compare low- and high-viscosity bulk-fill composites for Knoop microhardness (KHN), microtensile bond strength (MTBS) to dentin in occlusal cavities, and fracture strength (FS) in molars with mesialocclusal-distal restoration. Disk-shaped samples with different thicknesses (2 or 4 mm) of low-viscosity (SDR Flow, Dentsply) and high-viscosity bulk-fill composites (Filtek BulkFill, 3M ESPE; and Tetric-N Ceram Bulk Fill, Ivoclar Vivadent) were prepared for top and bottom KHN analysis (n=10). MTBS to dentin and fracture pattern was evaluated in human molars with occlusal cavities restored with (n=10): conventional nanocomposite (Z350XT, 3M ESPE), low-viscosity (Filtek Bulk-fill Flow, 3M ESPE) or high-viscosity bulk-fill composites (Filtek BulkFill). The FS and fracture pattern of human molar with mesial-occlusal-distal restorations submitted or not to thermomechanical cycling were investigated (n=10) using: intact tooth (control), and restoration based on conventional microhybrid composite (Z250, 3M ESPE), low-viscosity (SDR Flow) or high-viscosity bulk-fill composites (Filtek BulkFill). The data were submitted to split-plot ANOVA (KHN), one-way ANOVA (MTBS), two-way ANOVA (FS) followed by Tukey’s test (α=0.05). For KHN, there was no significant difference for the resin composites between the top and bottom. For MTBS, no significant differences among the materials were detected; however, the low-viscosity composite presented lower frequency of adhesive failures. For FS, there was no significant difference between composites and intact tooth regardless of thermomechanical cycling. Low- and high-viscosity bulk-fill composites have comparable microhardness and microtensile bond strength when used in occlusal restorations. Likewise, the bulk-fill composites present similar fracture strength in molars with mesio-occlusal-distal restorations.