The objective of this study was to evaluate the compressive strength of a glass fibre reinforced (GFR) composite material used in restorative conservative dentistry. The following dental composites were used in the work: EverX Posterior (GC Europe) GFR composite and Filtek Z250 (3M ESPE) conventional composite for fabricating phantoms which imitated molar crowns. Compression tests were performed and an analysis is provided here for the fractures formed during the application of compressive forces. It was found that the short fibres, rather than the polymer matrix itself, were responsible for the load transfer. The voids visible after removal of the fibres and the cracks in the polymer matrix are indicative of a force required to cause a GFR composite failure that is higher than the force required to cause a conventional composite filling failure. The phantoms made of the GFR composite showed greater strength than polymer-filled phantoms, devoid of short glass fibres.