Palatal radicular groove leads to severe endo-periodontal lesion in lateral incisors. The groove occurs on the labial and lingual root surfaces, while the localized periodontal pocket develops along the lingual groove length. The compli-cated root canal system, extensively destroyed bone lamella, and persistent fistula pose a challenge for root canal therapy, tooth retention, and thorough infection control inside and outside of the root canal. Combining microscopic root canal therapy with intentional replantation and nano-biomaterial application facilitates infection control, tooth retention, and formation of newly periodontal attachment.