The Effect of Two Bulk-Fill Resin Composites on Fracture Resistance of Endodontically Treated Teeth

Abstract

Objectives:The aim of this study was to compare the effect of two commercially available bulk-fill restorative materials on the fracture resistance of endodontically treated human molar teeth. Materials and methods:A total of 44 mandibular third molar were divided into four groups: Group 1; 4 mm thick bulk-fill fluid composite (SDR ™, Dentsply, Konstanz, Germany) was applied to the cavities. The restoration of the proximal walls and the occlusal region was completed with posterior composite (Valux Plus, 3M ESPE, St.Paul, MN, USA). Group 2; 4 mm thick fiber-resin reinforced bulk-fill composite (EverX Posterior; GC Corp., Japan) was placed in the cavities and the procedure in Group 1 was repeated. Group 3 (negative control group); no restoration was applied to the cavities. Group 4 (positive control group); comprised intact molar teeth without any treatment. The root canals were shaped using rotary instruments, irrigated with NaOCl, and obturated. All samples were incubated in distilled water at 37˚C for 1 week and then fracture strength test was performed. The values were recorded in Newton and the data were evaluated using Kruskal Wallis and Mann-Whitney U test.Results: No statistically significant difference (p >0.05 ) was observed between group 1, 2, and the positive control group. However, the bulk-fill fluid composite material showed higher fracture resistance than the fiber-resin reinforced composite material (p<0.05). The highest fracture resistance was observed in the positive control group.The fracture resistance of the negative control group was statistically lower than the other groups (p<0.05). Conclusions:Both of the bulk-fill restorative materials in endodontically treated teeth showed similar fracture resistance to intact teeth. In addition, the clinical use of the bulk-fill fluid composites may be recommended because of their high fracture resistance and ease of application.