Abstract: Being adjacent to mandibular second molars, most of fully impacted mandibular third molars often lead to distal bone defect of adjacent second molars after extraction, which is often manifested and aggravated by the original bone defect before extraction. Also symptoms of mandibular second molars may occur, such as formation of periodontal pocket, distal root absorption, erosion and even looseness of second molar resulting in extraction. So it is of great significance to repair the distal bone defect of second molar, which is affected by many factors, such as age, pre-operative impacted state of third molar, and the surgical methods. At present, there are various prevention and repair methods for different influence factors of the distal bone defect of second molar, such as bone/bone substitute graft, guided bone regeneration, and cell active ingredient transplantation etc. But all the existing repair methods have deficiencies, such as high economic costs, or leading to bone resorption and reducing the amount of new bone formation. This ?review? aims? to? summarize? the? research? progress ?on? the influence factor, prevention and repair methods of distal bone defect of adjacent second molar after extraction of fully impacted mandibular third molars.

Key words: Mandibular third molar, mandibular second molar, bone defect repair