Handling and Mechanical Properties of Low-viscosity Bulk-fill Resin Composites

Abstract

SUMMARY This study aimed to evaluate the filler contents (FCs), flexural properties, depth of cure (DOC), wear resistance, and handling properties of different low-viscosity bulk-fill resin composites (LVBRCs) and to determine the correlations between the tested parameters. Six LVBRCs, Beautifil-Bulk (BBF), Bulk Base Hard (BBH), Bulk Base Medium (BBM), Filtek Bulk-Fill Flowable Restorative (FBF), G-ænial Bulk Injectable (GBI), and SDR flow+ Bulk-Fill Flowable (SDR) were used. The DOC and flexural property tests were conducted according to the ISO 4049 specifications. The flexural strength, elastic modulus, and resilience were determined in 12 specimens that were obtained from each of the 6 materials. Sliding-impact-wear testing was conducted by evaluating the wear facets of the specimens using a noncontact profilometer and by confocal laser scanning microscopy. The handling properties of the LVBRC was assessed via extrusion force and thread formation measurements. The DOC for the majority of the LVBRCs was approximately 4 mm. Although the FCs and mechanical properties were material dependent, some LVBRCs exhibited excellent flexural properties and wear resistance. The LVBRCs demonstrated a wide range of extrusion force and thread formation. Regarding the correlations between the tested parameters, extremely strong negative and positive correlations were observed for the DOC versus extrusion force, flexural strength versus elastic modulus, maximum depth versus volume loss, and maximum depth versus thread formation. In addition, strong correlations between FCs and DOC, resilience, wear resistance, and extrusion force were observed.

Contemporary flowable bulk-fill resin-based composites: a systematic review

“…Most studies included in this systematic review reported mean flexural strength values above 80 MPa ( Table 7 ), fulfilling the requirements of the ISO 4049 standard [ 12 ] for type-1 resin composite materials. Among the reported flowable BF-RBC, the highest values were obtained by X-tra base (139.4 MPa) [ 24 ], G-aenial Bulk Injectable (143.9 MPa) [ 25 ] and Filtek Bulk Fill Flow (144.9 MPa) [ 26 ]. On the other hand, only four studies reported flexural strength values below the 80 MPa threshold [ 6 , 26–28 ].…”