The causes of protruding lower mouth include protruding outward growth of the lower teeth, skeletal developmental deformities, overly thick lower lip, etc. The causes of protruding lower mouth can be corrected by braces. The cause of the teeth can be corrected by braces, and the bone problem should be corrected by surgery. Choose the right hospital and get the right treatment. 1. Outwardly protruding lower teeth: this is the reason why most people have protruding lower lips, which can be gradually corrected by going to the hospital, adjusting the gap between the teeth and aligning the teeth, retracting the lower teeth and wearing braces for a long period of time. 2. Skeletal deformity: This is usually due to the natural protruding alveolar bone, which may cause a slurred speech in addition to the incongruity of the appearance. This kind of treatment usually needs to be treated by surgical orthodontic surgery. 3. Lower lip is too thick: generally can be changed through lip surgery. If the protruding lower lip has an impact on your life, please make sure to choose a regular hospital and choose the treatment according to the specific situation.