Mechanical Properties of Calcium Fluoride-Based Composite Materials.

Aim of the study was to evaluate mechanical properties of light-curing composite materials modified with the addition of calcium fluoride. The study used one experimental light-curing composite material (ECM) and one commercially available flowable light-curing composite material (FA) that were modified with 0.5-5.0 wt% anhydrous calcium fluoride. Morphology of the samples and uniformity of CaF distribution were analyzed using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). Mechanical properties were tested after 24-hour storage of specimens in dry or wet conditions. Stored dry ECM enriched with 0.5-1.0 wt% CaF showed higher tensile strength values, while water storage of all modified ECM specimens decreased their tensile strength. The highest Vickers hardness tested after dry storage was observed for 2.5 wt% CaF content in ECM. The addition of 2.0-5.0 wt% CaF to FA caused significant decrease in tensile strength after dry storage and overall tensile strength decrease of modified FA specimens after water storage. The content of 2.0 wt% CaF in FA resulted in the highest Vickers hardness tested after wet storage. Commercially available composite material (FA), unmodified with fluoride addition, demonstrated overall significantly higher mechanical properties.