The aim of this in vitro study was to compare the organic tissue dissolution capacities of 3 different irrigation agitation techniques (IATs) in artificial internal root resorption cavities (IRCs). Ninety freshly extracted maxillary human incisors were selected. After decoronation procedure, the roots were split longitudinally, and a standard IRC were prepared in the canals on each half of the roots. Then, the bovine pulp samples (~2,3 mg) were previously weighed and placed into the cavities. The root fragments were reassembled and cemented to create a circular IRC within the canal. Teeth samples were randomly divided into 6 groups (n=15); sodium chlorur (NaCl) and sonic irrigation (SI), sodium hypochlorite (NaOCl) and SI, NaCl and passive ultrasonic irrigation (PUI), NaOCl and PUI, NaCl and laser activated irrigation (LAI), NaOCl and LAI. After that, the teeth were decemented and the tissue samples inside the cavities were weighed again. The percentage of weight loss was calculated and statistically analyzed. SI has significantly more successful results than PUI and LAI in groups which the irrigant was NaCl. There was also a significant difference between LAI and PUI in groups which the irrigant was NaOCl (Group 6 ˃ Group 4, p=0.003). There was no significant difference between LAI and SI with NaOCl. Complete dissolution of bovine pulp tissue from IRCs was not achieved by any tested techniques. However, the LAI with NaOCl was more effective than other IATs. In addition, there is no significant difference between the LAI and SI with NaOCl.