Abstract
Fifty-three years old female visited a dental clinic with a chief complain of uncomfortable feeling during mastication at left molars in mandibular. The lower left first premolar reacted to a vertical percussion test and was diagnosed as not vital by electric pulp test. Diffuse radiolucent lesion was observed on a X-ray image at distal to the dental root. Moreover, a large lateral root canal was revealed to extend from half of the root to the lesion with dental cone-beam CT. Root canal treatment was performed as usual with application of calcium hydroxide in root canal. Root canals were finally filled with gutta-percha points and a sealer after 3-month follow-up. The diffuse radiolucent lesion was not observed on X-ray image one year after the root canal filling with good prognosis. Definite diagnosis with dental cone-beam CT is very important as there are a number of reasons for bone resorption lateral to a dental root.
https://ror.org/03bwzch55 
