Bulkfill Flowable Resin Based Composite: Evaluation of Different Physical Properties

Objectives: To evaluate and to compare the depth of curing, compressive strength and mircrohardness of a newly introduced flowable composite material(Filtek™ Bulk Fill Flowable Restorative, 3M, ESPE) with a conventional resin-based nano composite(Filtek™ Supreme Ultra Universal Restorative 3M, ESPE); and the wear resistance of the two composite systems against natural teeth(enamel) and porcelain crowns.
Methods: Composite samples(n= 20/group) of the two materials were fabricated in stainless steel molds 4mm diameter and 6mm height and curing depth was measured using digital caliper. Curing depth test was done according to ISO recommendations (Specification 4049). Composite samples(n=20/group) of the two materials were fabricated, in the same dimensions and tested for compression strength using Instron(Instron^® 5566A, Norwood, MA) universal testing machine. For the micro hardness test, composite samples(n=13/group) of the two materials were prepared, 8mm diameter and 2mm thickness and Knoop hardness test was performed. Composite discs(n=6/group) were made in 11mm diameter and 3mm thickness and wear resistance was tested against extracted human teeth and porcelain crowns. Independent-samples t-tests were used to analyze the data.
Results: There was a statistically significant difference between the two materials in the curing depth and microhardness(p<.05). No significant difference in compressive strength was observed between the tested materials(p>.05). Regarding the wear resistance there was a statistically significant difference between the two materials when tested against both teeth and porcelain(p<.05).
Conclusions: Within the limits of the present study the resin-based nano composite was found to have greater microhardness and wear resistance as compared to the bulk fill composite. The difference between the two materials in compressive strength was not statistically significant. Curing depth was greater in the bulkfill as compared to the resin-based nano composite.