①The labiolingual axis and incisal edge are perpendicular to each other, and the left and right sides are symmetrical.

②The labial surface and incisal edge intersect obliquely, and the left and right sides are asymmetrical.

The incisal edge of the central incisor runs almost horizontally, making the crown symmetrical when viewed from the buccal or lingual side. In contrast, incisal edge of the lateral incisor tilts significantly downward, making the crown asymmetrical in shape.