Effect of immediate preendodontic dentin sealing on the fracture strength of endodontically treated teeth: An in vitro study

Introduction: Sodium hypochlorite (NaOCl) is a standard endodontic irrigant but may impair resin–dentin bonding. Immediate pre-endodontic dentin sealing (IPDS) may preserve bond integrity; its effect on fracture strength (FS) requires evaluation. Aim: To compare effects of IPDS versus late dentin hybridization (LDh) combined with different irrigation activation methods on FS of endodontically treated teeth. Materials and Methods: 35 mandibular premolars divided into groups (EDH with Sonic, Ultrasonic, or Side-vented needle activation; LDh with the same activations) and a sound-tooth control. Standardized MOD prep, endodontic treatment, restorations. FS assessed with universal testing machine after thermocycling. Results: Teeth with immediate pre-endodontic dentin sealing combined with ultrasonic irrigation showed greater fracture resistance than other groups. Conclusion: IPDS, particularly when paired with ultrasonic irrigation, may improve fracture resistance of endodontically treated teeth.