Objective To investigate the clinical characteristics,diagnosis and treatment of severe combined peri-odontal-endodontic lesions in a double-rooted maxillary lateral incisor with a palatal radicular groove and to provide a reference for clinical diagnosis and treatment.Methods A patient with a double-rooted left maxillary lateral incisor with a palatal radicular groove and severe combined periodontal-endodontic lesions underwent complete root canal thera-py and intentional replantation,and a retrospective analysis of the management of this type of patient was performed based on the literature.Results The 3-year follow-up examination revealed no discomfort,good healing of the upper left lateral incisor,no pathological loosening,and a palatal gingival sulcus was found at a depth of approximately 1 mm.Review of the literature showed that the prognosis of the affected tooth and the choice of treatment plan were correlated with the length and depth of extension of the lingual groove toward the root,the periodontal condition and the pulpal sta-tus of the affected tooth.For minor PRGs or for affected teeth with no loss of pulpal viability,flap surgery and odonto-plasty can be used to avoid endodontic treatment or retreatment.For deep or long lingual grooves that result in signifi-cant loss of periodontal tissue,endodontic treatment,odontoplasty,or closure of the grooves and guided tissue regenera-tion are needed.In the case of PRGs with double root formation,the affected tooth can be preserved via root canal thera-py,removal of the small root and filling with apical restorative material,and intentional replantation.Conclusion In cases of severe combined periodontal-endodontic lesions due to palatal radicular grooves occurring in double-rooted maxillary lateral incisors,clinical presentation and imaging can prevent missed diagnoses,and appropriate treatment should be based on the length and depth of lingual grooves extending toward the roots,periodontal conditions,and pulp-al status of the affected teeth.