Endodontic treatment is based on two complementary principles: mechanical and chemical preparation of the root canal system. Studies have demonstrated that endodontic instruments are capable of preparing only approximately 65-80% of the root canal wall surface, with the remaining substantial portion of the canal system insufficiently cleaned. Chemical canal preparation involves irrigation with specific solutions, such as sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA), and chlorhexidine, which facilitate the dissolution of organic debris, eliminate microorganisms, and remove the smear layer. The primary objective of this study was to evaluate structural alterations in dentin resulting from exposure to sodium hypochlorite, one of the most widely used irrigating agents in endodontic therapy. Additionally, the study investigated the influence of sodium hypochlorite on the microstructure and mechanical properties of teeth, with particular emphasis on compressive strength. Human teeth extracted for orthodontic reasons, including canines and first premolars with single root canals, were used as the study material. The teeth included in the study represented two anatomical groups: canines and premolars. Five premolars and five canines were used as control groups, and five premolars and five canines were used in the study groups. Teeth with similar root and crown dimensions were selected. The specimens were randomly assigned to two groups: a control group consisting of teeth not exposed to 5.25% NaOCl and an experimental group comprising teeth irrigated with 10 ml of sodium hypochlorite in three cycles, each lasting two minutes. The samples were subsequently subjected to failure load testing, microstructural analysis, and elemental composition assessment using energy-dispersive X-ray spectroscopy (EDS). In addition, statistical analysis was performed using the Shapiro-Wilk test. The results demonstrated that both canines and premolars exposed to NaOCl exhibited reduced failure load compared with the control specimens. Canines showed greater resistance to failure than premolars. Furthermore, sodium hypochlorite was found to affect the elemental composition of dental tissues.