Periodontal regenerative therapy offers new options for treating teeth with severe bone loss. However, debate persists over preventive root canal treatment when bone resorption extends beyond the root apex. This report examines periodontal regeneration and pulp vitality preservation, challenging conventional treatment. A 65-year-old man presented with 10 mm periodontal pockets and bone resorption extending beyond the root apex of tooth #42. Pulp vitality was confirmed, and periodontal regenerative therapy was performed without preventive root canal treatment. Root debridement excluding the apical 2 mm was performed and verified using cone-beam computed tomography (CBCT), followed by application of enamel matrix derivative (Emdogain®), deproteinized bovine bone (Bio-Oss®), and a collagen membrane. At 6 months, probing depths decreased from 10 mm to 3 mm without bleeding on probing. Radiographs showed bone regeneration. At 5 years, probing depths remained stable at ≤ 3 mm, and CBCT confirmed long-term bone stability. Pulp vitality tests remained positive. The findings from this case suggest that root debridement excluding the apical 2 mm and precise regenerative techniques can promote periodontal regeneration and maintain pulp vitality, questioning the need for routine preventive endodontics. Further research is needed to establish protocols for complex cases.