One hundred forty-three patients aged 24-56 with chronic apical periodontitis were included in the study. The patients were divided in two groups according to treatment options: 51 patients underwent conventional root canal treatment (control group) and in 92 treatment was accomplished by hydrodynamic irrigation (main group). The main group was also subdivided in two subgroups, one of which received hydrodynamic irrigation with 3% sodium hypochlorite (47 patients) and the other additionally received laser root canal therapy. The patients were followed-up 7 days, 6 months and 2 years after procedure. The results showed that bone restoration occurred 1,3 times more rapidly in hydrodynamic irrigation and laser therapy group than by conventional treatment protocol.