Objective To assess the clinical outcomes of dual-wavelength laser-assisted versus ultrasonic-assisted single-visit root canal treatments in molars with chronic apical periodontitis(CAP).Methods Two hundred and forty molars diagnosed with CAP were equally randomized into either a dual-wavelength laser-assisted or ultrasonic-assisted treatment group.The study compared bacterial counts in the root canal immediately after disinfection,post-treatment pain using the Visual Analogue Scale(VAS)at one week,and clinical efficacy through the Periapical Index(PAI).Levels of interleukin-8(IL-8),interleukin-17(IL-17),tumor necrosis factor alpha(TNF-α),and C-reactive protein(CRP)were measured using enzyme-linked immunosorbent assay(ELISA)before and one week post-treatment.Bone density was evaluated via periapical X-rays and mean gray value(MGV)analysis both before treatment and at a six-month follow-up.Results Both groups exhibited significant reductions in bacterial counts post-disinfection(P<0.01),with the dual-wavelength laser group showing significantly lower levels than the ultrasonic group(P<0.05).The laser group reported lower pain levels and incidence one week post-treatment(P<0.05).At the sixth month,the laser-assisted group demonstrated a higher rate of treatment success(P<0.05).Post-treatment inflammatory markers IL-8,IL-17,CRP,and TNF-α were lower,and the MGV indicating bone density was higher in the laser group compared to the ultrasonic group(P<0.05).Conclusion Dual-wavelength laser-assisted root canal treatment reduces post-treatment pain,has a higher success rate for molars with CAP,and offers superior clinical efficacy to compare to ultrasonic-assisted treatments.