There is an incidence of periodontal pocket formation and gingival recession on the distal of the lower second molar due to bone defect after third molar surgical removal. Patient referred suffering from recurrent pericoronities; after clinical and radiographic examination, the lower left 3rd molar is partially erupted and angulated in mesial direction. The radiograph shows there is bone deficiency on the distal of the adjacent 2nd molar. After 3rd molar surgical removal, cancellous bone graft placed on the socket with guided bone regeneration (GBR) procedure and complete primary closure with rotational flap. Patient follow-up after 3 and 6 months, bone formation observed on the distal of 2nd molar with the absence of periodontal pocket. Third molar socket bone grafting with cancellous allograft may be a predictable procedure to prevent periodontal pocket on the distal of the second molar.