Aim: The aim of this study was to retain symptomatic tooth number 22 with periapical lesion, possessing total root canal obliteration with Vertucci classification type V, through endodontic retreatment and fiber post application. Case Description: A 26-year-old male patient, systemically healthy, presented to our clinic with complaints of pain and aesthetic issues. According to the history obtained from the patient, it was revealed that root canal treatment had been performed 3 years ago, and he had been experiencing pain for the last 2 months. Clinical examination revealed the absence of coronal restoration, and positive findings were noted during palpation and percussion tests. After radiological examination, the presence of a periapical lesion and inadequate canal filling due to root canal configuration classified as Vertucci type V were determined. Retreatment was decided upon. In the first session, the canal filling was removed, and root canal preparation was completed with K-type hand files under 2.5% NaOCl irrigation (MAF #50). Following the removal of the filling, calcium hydroxide was applied as medication. After 10 days, MTA was applied under dental operating microscope for canal obturation. Fiber post and composite were used for post-core restoration. The patient was referred to the prosthodontic department for permanent crown restoration. Findings: Follow-ups were conducted at 1 and 3 months, revealing clinical asymptomatic status. Conclusion: It has been demonstrated that the retreatment of root canal-treated teeth with periapical lesions and Vertucci type V canal configuration can be successfully improved with accurate diagnosis and appropriate magnification.