Mechanical and chemical treatment and filling of root canals are integral parts of endodontic therapy. The fillers which are used in the root canal filling phase aim to hermetically seal the endodontic space and prevent conditions conducive to further bacterial growth. A large number of fillers with different compositions are available on the market. However, nowadays the advantages of using bioactive materials are increasingly emphasized. Better biological and physical-mechanical properties are manifested in their biocompatibility, antimicrobial effect, accelerated healing of periapical tissue, and the deposition of hydroxyapatite crystals, due to which they achieve a chemical bond with dentin. The research was conducted to test the bond strength of a new material based on polydimethylsiloxane with the addition of bio-glass in the composition of the material (GuttaFlow bioseal) and to compare it with a standard material based on polydimethylsiloxane (GuttaFlow 2). For this research, fourteen single-rooted teeth were chemo-mechanically processed and divided into two test groups filled with two different materials. The samples were embedded in acrylic resin and cut into 1 mm thick slices using an Isomet saw. An average of 8 samples was obtained from each tooth. The force required to break an individual sample was tested with a "push out" test. The results of this research showed that there is no difference in bond strength between dentin and the tested materials.