A flap design for the mandibular third molar extraction is important for a successful procedure. Inappropriate flap could result in unfavourable outcomes. By performing sufficient simulation before mandibular third molar removal, complications can be avoided and widely applied. Although there are few variations in flap design for mandibular third molar extraction, it is possible to perform mandibular third molar extraction faster and safer by making an appropriate incision, and it can be modified on a case by case basis.