This study evaluated copper sulfide penetration dynamics during electrophoresis in the root canal system of mandibular anterior teeth. Twenty intact mandibular anterior teeth were included, extracted for prosthetic purposes from patients aged 40 to 65 years. The research comprised two phases: macroscopic and histological analysis. In the first group (n=8), electrophoresis involved a copper-calcium hydroxide-based compound (Cupral™) administered in two sessions, with a 7-day interval between them. The second group (n=8) received a combination-paste of Cupral and Ca(OH)₂-highly dispersed paste. A third group (n=4) served as a comparison group. Electrophoresis was conducted by immersing teeth with opened endodontic cavities in a plastic container filled with 0.9 % saline. Canal entrances were explored using a hand K-file, followed by canal drying and application of the corresponding paste to create an endodontic reservoir. Electrophoretic current was then applied at an intensity of 5 mA x min per canal. Teeth were fixed in 10% neutral buffered formalin for histological examination. Macroscopically, the first group exhibited aesthetically unacceptable turquoise blue staining of the crown and root. In contrast, the second group showed no staining of this intensity. Histological examination of the first group revealed copper sulfide penetration into predentin and dentinal tubules, while the intertubular dentinal matrix remained unstained. The second group exhibited slight impregnation of copper sulfide in some areas of predentin, with uneven distribution within the dentinal tubules. The third group displayed a normal dentin structure in the root canal walls. This research provides valuable insights for improving endodontic outcomes and expanding treatment options available to clinicians.