What are the most important properties of a flowable composite used for the flowable injection technique? Personal experience shows that balanced optical properties are essential, with an appropriate translucency, blend-in ability and surface gloss leading the way. However, the mechanical properties are also important, not least because the restorative material will be in direct contact with the antagonist teeth. And finally, handling properties are essential: The right level of flowability is needed for proper injection, while a void-free application is required for an intact, stainresistant surface.