Objective To evaluate the application of cone beam CT and digital X-ray in refractory apical periodontitis(APO). Methods Sixty-six patients with refractory APO were divided into cone beam and traditional groups based on the cone beam CT and digital X-ray. The diagnostic rate, number of root canal treatment, and 6-month therapeutic efficacy were compared between 2 groups. Results Compared with traditional group, diagnostic rate was increased(87.5% vs 29.4%, P<0.01), number of root canal treatment was decreas...