Evaluation of Fracture Strength of Fiber-Reinforced Direct Composite Resin Restorations: An In Vitro Study

Abstract

This in vitro study aimed to compare the fracture strength of direct non-reinforced class II composite resin restorations and polyethylene fiber-reinforced restorations, and also to investigate the influence of the locations of polyethylene fibers within the cavity on the fracture strength. Sixty freshly extracted human teeth were disinfected and prepared (class II cavity design). The teeth were assigned randomly into four groups (n = 13). Group I (control) was restored with nano-hybrid composite resin. The other three experimental groups were restored with the same composite resin material reinforced by polyethylene fibers (Ribbond) at different locations. Fibers were placed either on the axial wall (Group II), on the gingival floor (Group III), or on the axial wall and pulpal/gingival floor (Group IV) of the proximal cavity. All the teeth were subjected to thermocycling to simulate the oral environment. The fracture strength was measured using a universal testing machine. Group IV had the highest mean fracture strength at maximum load (148.74 MPa), followed by Group II (140.73 MPa), Group III (136.34 MPa), and Group I (130.08 MPa), with a statistically significant difference from the control group (p = 0.008) but not between groups II and III.

Fracture Resistance of Fiber-Reinforced Composite Restorations: A Systematic Review and Meta-Analysis

“…This may be attributable to a stress transfer from the polymer matrix of the resin composite within the fiber devices, which have high tensile strength, thus causing lower stress to be transmitted to the remaining tooth structure. Fiber devices may thereby be able to better promote a load spread and distribution within the composite resin restoration [ 29 , 30 , 33 , 40 ].…”

“…Twenty-two of those studies tested molars and/or premolars with mesial–occlusal–distal cavities (MOD), while one study used mesial–occlusal cavities (MO) [ 33 ] and another involved occlusal, MOD and MO cavities [ 35 ]. Twenty studies used teeth with root canal treatment and four studies did not perform any root canal treatment on the extracted teeth [ 29 , 30 , 32 , 40 ]. Two studies evaluated the effects of using fiberglass [ 41 , 44 ], two studies used fiberglass posts [ 39 , 50 ], two studies used fiberglass and post devices for fiber reinforcement of restorations [ 33 , 36 ], three studies compared glass and polyethylene fibers [ 40 , 43 , 51 ] and the other fifteen studies tested only polyethylene fibers.…”

“…The outcomes of twelve in vitro studies [ 29 , 30 , 31 , 33 , 34 , 40 , 42 , 43 , 48 , 50 , 51 , 52 ] reported increased fracture resistance mean values for fiber-reinforced composite restorations when compared to groups of non-fiber-reinforced composite restorations. In three of the in vitro trials, the results indicated that fiber-reinforced composite restorations had lower fracture resistance mean values than those of non-fiber-reinforced composite restorations [ 44 , 45 ], and in nine studies the authors reported no significant difference in the fracture resistance mean values of the several groups tested.…”

“…Agrawal et al [ 29 ] and also Balkaya et al [ 31 ] found better results for composite restorations reinforced with polyethylene fibers (Ribbond ® , bondable reinforcement ribbon, Ribbond Inc., USA) when compared to restorations with EverX Posterior TM (GC, Europe, Street Alsip, IL, USA), a fiber-reinforced composite designed by the manufacturer to be used as dentin replacement in combination with a conventional composite. Hshad et al [ 42 ] and Albar and Khayat [ 30 ] also reported increased fracture resistance for teeth restored with polyethylene fibers compared to teeth restored with composite without fibers. Shafiei et al [ 34 ] found the same results when they combined Ribbond ® , positioned at the background surface, both pulp and axial walls of the cavity preparation, with a nanohybrid composite.…”

Fracture Load of Mesio–Occluso–Distal Composite Restorations Performed with Different Reinforcement Techniques: An In Vitro Study

“…Few published studies have focused on comparing the various modern reinforcement techniques with conventional composite restorations [ 8 , 13 , 22 , 25 ]. To date, there has been little research directly examining the maximum fracture load of MOD cavity preparations restored with different reinforced fiber resins.…”