The point closest to the apex of the gum curve is the apex of the gum;

The gingival plane means that the line between the upper central incisor and the pointed gingival tip is the gingival plane, which should be parallel to the line between the bilateral pupils and the anterior occlusal plane and perpendicular to the facial midline;

Gum height refers to the relative height of the gingival apex of the upper ring teeth in the vertical direction.