Effects of Finishing and Polishing Methods on the Surface Roughness and Surface Free Energy of Bulk-fill Resin Composites

Abstract

SUMMARY The purpose of this study was to determine the influence of finishing and polishing methods on surface properties of bulk-fill resin composites through surface roughness (Ra) and surface free energy (SFE) measurements, and scanning electron microscopy (SEM) observations. Three bulk-fill resin composites, Tetric EvoCeram Bulk Fill (TB), Filtek Bulk Fill (FB), and Filtek Bulk Fill Flowable Restorative (FF), and two conventional resin composites, Clearfil AP-X (AP) and Estelite ∑ Quick (EQ) were used. Seventy cured specimens of each resin composite were prepared and divided into seven groups of 10 specimens. Ra, SFE measurements, and SEM observations were conducted after finishing and polishing procedures. Three groups of specimens were finished with a fine grit diamond bur (FDB), and three with a tungsten carbide bur (CBB). After finishing, one group from each type of finishing was polished with aluminum oxide flexible disks (SSD) and one group from each type of finishing was polished with diamond particles embedded in a silicone point (CMP). A baseline group of samples that were neither finished nor polished after removing the translucent strips from the surface was examined. Although the baseline group showed significantly lower Ra values than the other groups, most resin composites showed lower Ra values with CBB+SSD than with the other finishing and polishing groups. Among the tested resin composites, EQ showed significantly lower Ra values than the other resin composites, regardless of the finishing and polishing methods. On the other hand, AP showed significantly higher Ra values than the other resin composites in all finishing and polishing groups, apart from FB with FDB. For the finished specimens, most resin composites showed higher SFE values with CBB than with FDB. For the polished specimens, all the tested resin composites with CMP showed lower γS values than those with SSD, regardless of the finishing method. The baseline groups of TB and FB showed significantly lower SFE values than the other finished and polished groups. In the SEM observations, all the examined resin composites showed rougher surfaces after finishing with FDB than with CBB. However, when comparing the different polishing methods (CMP and SSD), surface smoothness appeared to be material dependent.

Effect of Fluoride Gels on the Surface Roughness of Different Composite Resins

“…In addition, the surface roughness generally determines the mechanical performance of a material. This is because irregularities on the surface are favorable places for the formation of cracks or corrosion [31,32], as confirmed by the results of this study. Thus, it is unfavorable to proceed with topical fluoride phosphate acidulated in teeth with composite resin restorations.…”

The Effect of Finishing and Polishing Sequences on The Surface Roughness of Three Different Nanocomposites and Composite/Enamel and Composite/Cementum Interfaces

“…Numerous studies have investigated the effect of different finishing and polishing procedures on the surface roughness of resin composites [ 24 , 25 , 26 , 27 ]. However, with the development of new composites and modern finishing and polishing systems, it is necessary to continuously update evaluations of the impact of different polishing procedures on surface quality.…”

Surface Geometry of Four Conventional Nanohybrid Resin-Based Composites and Four Regular Viscosity Bulk Fill Resin-Based Composites after Two-Step Polishing Procedure

“…Composite polishing is a difficult procedure because of heterogeneous nature of composite resin, i.e., tough particles of inorganic filler embedded in a relatively soft organic matrix [ 3 , 4 , 6 ]. Roughness of RBC surface depends on type and properties of polishing instrument as well as structure and properties of the composite material and interactions between them [ 2 – 5 , 9 – 11 ]. According to St-Pierre et al, material-dependent factors that affect surface roughness are (1) the resin matrix content and formulation, (2) the filler particle characteristics (type, hardness compared with the abrasiveness of the polishers, size, and shape), (3) the composite resin filler load, (4) the quality of the silane coupling agent, and (4) the degree of conversion after light curing [ 10 ].…”

“…Bulk fill composite materials, due to the need of polymerization shrinkage reduction, often contain large, irregular filler particles in their structure, which can suggest worse polishability compared to conventional composites. However, studies comparing the roughness of bulk fill and conventional composites are very limited [ 5 , 11 , 30 , 31 ].…”