Comparison of Microhardness and Surface Roughness of New Nanofiber Filled Flowable Composite

Abstract

Objective: This study aimed to compare the microhardness and surface roughness (Ra) of a resin composite, which was recently introduced to be the first flowable composite with the nano-sized fiber filler, with the particle filled composite resins with different properties, used in Class V cavities. Methods: Totally 100 disc-shaped samples (diameter: 4 mm, height: 2 mm) were prepared and divided into five groups in accordance to the different types of composites (n=20): 1) Flowable composite with nano-fiber filler (Group N: NovaPro Flow, Nanova, USA); 2) Flowable bulk-fill composite [Group Estelite Bulk Fill Flow (EBF): Tokuyama, Japan]; 3) Flowable composite [Group G-aenial Universal Flo (GUF): GC Corp, Japan]; 4) Highly-filled flowable composite [Group G-aenial Universal Injectable (GUI): GC Corp, Japan]; 5) Micro-hybrid composite (Group Z250: Filtek Z250, 3M ESPE, USA). They were polished with aluminum oxide polishing discs. Ra measurements (µm) were made using contact profilometer (MarSurf M 300 C; Mahr GmbH, Germany) (n=10). Vickers microhardness evaluations were made using HMV microhardness tester (Shimadzu, Japan) (n=10). Three dimensional (3D) optic profilometer was used to evaluate the surface topography. One-way ANOVA, Shapiro-Wilk and Tukey tests were used for statistical analysis (p<0.05). Results: At top and bottom surfaces, Group N showed significantly lowest microhardness values while Group Z250 showed significantly highest microhardness values than other groups (p<0.05). Group GUI showed significantly higher microhardness values than group EBF and GUF (p<0.05). Hardness ratio was found lower than 80% in Group N. No significant differences in Ra were found between the groups. 3D optic profilometer revealed that similar scratch appearances were detected in all groups. Conclusion: Incorporation of flowable composite with nanofiber filler may not be advantageous for micro-hardness, hardness ratio and Ra properties.

Keywords

• class v restoration
• flowable composite
• nanofiber
• microhardness
• surface roughness