Effects of Different Irrigation Activation Techniques on the Healing of Large Periapical Lesions

The primary goal of endodontic treatment is to treat the infection by optimally cleaning the root canal system and precentig reinfection. Root canal preparation must be accompanied by an effective irrigation activation protocol to effectively remove foci of infection. Manual dynamic activation (MDA) is an irrigation activation method performed by up- and downmovements of a gutta-percha compatible with the final instrumentation size.Passive ultrasonic irrigation (PUI) is another activation technique based on the transmission of acoustic energy to the irrigant in the canal through a vibrating file or a thin wire with hydrodynamic activation. Sonic systems create a strong hydrodynamic phenomenon and increase the effectiveness of the solution by using flexible tips connected to special instruments that work with air pressure with low-frequency vibration. Recently, laser activation methods, defined as photon-initiated photoacoustic streaming (PIPS) and shock wave enhanced emission photoacoustic streaming (SWEEPS), which work with conical and radial fiber tips, have been developed. The main difference between PIPS and SWEEPS is that in SWEEPS, the double laser pulse applied to the irrigation solution causes the bubbles to collapse faster, allowing the photoacoustic shock wave to reach deeper into the root canal. Apical periodontitis is a condition in which microbial products in the root canal reach the periapical region, destroy adjacent bone tissue, and is characterized by a radiolucent area in the periradicular region of the affected tooth on a radiograph. Successful healing of apical periodontitis requires a reduction in the size of the radiolucent area and healing of the bone. The periapical index (PAI) system, which grades periapical pathology from 1 to 5 according to increasing radiographic appearance, helps to achieve consensus among clinicians in categorizing lesions. In addition, the healing process of chronic apical periodontitis can be objectively examined via fractal analysis, which can be used to assess the size and density of periapical lesions, the degree of healing of bone tissue, and the remodeling of the trabecular structure quantitatively. The aim of this study was to compare the effects of different irrigation activation methods (MDA, Sonic, PUI, PIPS, and SWEEPS) on healing in single-rooted mandibular premolar teeth with extensive periapical lesions of endodontic origin.