Keeping an open mouth posture can cause: dry and chapped lips, short and fast breathing; diminished strength of the muscles of the lips, cheeks, jaw and tongue; a lowered and more anterior oral rest posture of the tongue, leading to changes in aesthetics and position of teeth/occlusion (improper fit of the teeth); elongated face, retruded mandible, and palate (“roof of the mouth”) becoming more narrow and /or deep.