The instrument for perforating the periosteum flap in the dental mouth has a structure with a handle and two end points, one end is a triangular portion and the other end is a teardrop-like end, and the two are connected by a grip portion. The two end points are connected with the handle at a angle of twenty-five degrees to forty-five degrees, each of which is a turning portion and a reverse folding portion, so as to facilitate the flap in the lingual side or other difficult-to-access position of the mouth without obstruction.一種牙科口內骨膜翻瓣用器械，結構上有握柄與兩端點，一端點為三角形部而另一端點為似水滴狀端部，兩者之間由握柄部相連。兩端點與握柄呈二十五度角至四十五度角相接，各為轉折部與反轉折部，以利在口內舌側或其他難以進入位置翻瓣而無阻礙。
