Effects of Thumb/digits sucking in maxillaProclination of maxillary incisors: When a child places a thumb/finger between the teeth, it is usually positioned at an angle, so that it presses against the lingual palatal surface of the upper incisors and the lingual surface of the lower incisors. This direct pressure causes displacement of incisors. Increased arch length. Increased anterior placement of apical base of maxilla. Increase in SNA angle. Increased clinical crown length of maxillary incisors. Increased counter-clockwise rotation of occlusal plane. Decreased width of palate. Left/right side of anterior maxillary arch is usually deformed with deformation related to whether the right or left thumb is sucked. Atypical root resorption of primary central incisors. Trauma to maxillary central incisors (Primarily due to their prominence).Ref: Textbook of Orthodontics Gurkeerat Singh Second edition