Anterior tilt of the neck does not usually lead to convexity of the mouth, which may be related to genetic factors, bad habits and certain diseases. Usually, a forward tilt of the neck does not lead to a convex mouth because the movement of the mouth is mainly influenced by the jawbone, while the movement of the neck is mainly influenced by the cervical spine, and there is no direct relationship between the two, therefore, a forward tilt of the neck does not lead to a convex mouth. Convexity of the mouth is also known as deep coverage in clinical practice. Convexity of the mouth may be hereditary, if one of the two parents has congenital convexity of the mouth, his/her children will have a high probability of having convexity of the mouth; secondly, bad habits such as pouting and breathing with the mouth open can lead to convexity of the mouth; in addition, suffering from chronic rhinitis, enlarged tonsils, and other diseases, the patient has the habit of mouth-breathing, which is reflected in the opening and closing of the front teeth and the lips protruding, thus leading to convexity of the mouth. Common clinical methods to improve convexity include orthodontics, osteotomy of the front of the upper jaw and double jaw surgery. If you suspect the presence of convexity of the mouth, you should consult the doctor for examination and choose the appropriate improvement plan under the guidance of the doctor.