Mandibular fracture is a very rare but a serious complication associated with tooth extraction. Interestingly, mandibular angle fractures often include mandibular third molars on the fracture line, but the mandibular third molars are not always fully erupted but impacted in many cases. In addition, most of the mandibular third molars associated with fractures are not functioning. Conventionally, the teeth on the fracture line have been extracted in principle since these were prone to secondary infection and may be accompanied by osteomyelitis, resulting in bone union failure. However, there are reports that even if the teeth on the fracture line are preserved, there is no significant difference from the case that the teeth on the fracture line are extracted in the occurrence of postoperative complications. Sagittal split ramus osteotomy for jaw deformity, which is the most commonly used surgical orthodontic surgery, can also cause an unexpected fracture due to the presence of mandibular third molars.