This case report describes the diagnosis, multidisciplinary treatment, and long-term follow-up of a severely compromised tooth in a patient who was referred for assessing a gingival recession. Clinical evaluation of the left maxillary canine showed 12 mm of mid-buccal gingival recession, probing depth of 14 mm on the mesial-buccal aspect, and grade III mobility. A periapical radiograph revealed extensive periapical and lateral radiolucency. The first step of the treatment was to carry out oral hygiene instructions and full-mouth debridement. After that, endodontic treatment was performed immediately. Periodontal reevaluation four months after endodontic therapy revealed that probing depths of all sites were within 3 mm and periapical radiograph showed a slight decrease in periapical and lateral radiolucency. It was subsequently decided to perform root coverage with a laterally positioned flap and subepithelial connective tissue graft. Six months after surgery, the root surface showed 1 mm recession, representing root coverage of 91.7% and a gain of attachment of 13 mm. The patient was enrolled in a 6-month supportive periodontal therapy. Treatment outcomes were evaluated over 18 years, with successful radiographic and clinical results throughout the follow-up period. The successful management of endo-periodontal lesions requires an accurate diagnosis, which is imperative to provide proper therapy in the correct treatment sequence.