Resin-based composite materials are the materials of choice in everyday clinical work owing to the constant improvement of their physical-mechanical and aesthetic properties. Despite the numerous requirements they met, the problem of complex and time-consuming filling production remained due to the necessary installation of 2 mm thick layers. This led to the emergence of a new type of composite material called bulk-fill, according to the placement method. Changes in the composition of the bulk-fill material enabled polymerization to a depth of 4 mm and placement of the material in one layer, which shortened the duration of the restoration procedure and reduced the risk of iatrogenic errors. With the desire to further shorten the process of making fillings and thus facilitate the work of the therapist, modern bulk-fill composite materials have appeared on the market that support ultra-short polymerization without compromising the material's properties. The high-viscosity Tetric PowerFill and the low-viscosity Tetric PowerFlow from Ivoclar Vivadent are presented as materials that can be polymerized within 3 seconds using a 3050 mW/cm² curing unit due to innovative components in their composition. The β-allyl sulfone contained in the material is a chain-transfer fragmentation addition reagent (AFCT) that promotes the so-called step- polymerization. It leads to a reaction between the free radical and the double bond of β-allyl sulfone, thus terminating one polymer chain and releasing a sulfonyl radicals which can start a new polymerization reaction resulting in more homogeneous short-chain polymers and oligomers of fuller polymerization. The high translucency of the material required for light penetration at the beginning of polymerization is achieved by a close refractive index of light of the organic matrix and filler particles. In contrast, the material takes on a more opaque appearance during polymerization and acquires a natural appearance. They are indicated for restorations in the posterior region of permanent dentition, whereas they are contraindicated in cases of deep cavities when there is a possibility of heating of the dental pulp and consequent irreversible damage. Previous laboratory tests show that rapid polymerizing bulk-fill resin composites are an equivalent substitute to conventional composite materials for direct fillings in the posterior region of the oral cavity.