The objective of this case report was to introduce a treatment approach for the maxillary central incisor, diagnosed with a combined periodontic and endodontic lesion from a deep palatogingival groove that originated at a palatal fossa of the crown and ended at the root apex. The palatogingival groove is often found in both maxillary lateral and central incisors and is regarded as a local factor that promotes an accumulation of dental plaque which is difficult to remove and eventually contributes to localized periodontitis. Moreover, the groove’s depth and length influenced the severity of inflammation in periodontium and dental pulp. In this case report, the authors have proposed a novel treatment strategy for the affected tooth, i.e., root canal therapy and intentional replantation, using a new root canal filling material with good sealability, OrthoMTA, along with Biodentine™ to repair defective dentine within the palatogingival groove.