A gummy smile is a common term describing excessive gum tissue visible above the front teeth. When smiling, while it sometimes presents as a mostly aesthetic concern, it can also be a symptom of additional underlying issues with your bite. A gummy smile can have a variety of causes. It can be caused by a short or overly mobile upper lip, which results in the lip resting higher than normal. When smiling, an upper jaw being too long, also known as a vertical maxillary excess is a skeletal issue that can also cause the appearance of a gummy smile. A gummy smile can also be caused by abnormal eruption of the teeth, making the teeth appear shorter even though they are the correct length. Alternatively, the front teeth can also over erupt, resulting from an overbite and too much gum tissue being exposed, and in some cases of tooth wear, as the teeth shorten and continue to erupt to compensate, the gum line also moves downward, causing more of it to be revealed when smiling. Because there is such a wide range of possible causes of a gummy smile, it is important to work with your doctor to fully examine your mouth and help you determine the best course of treatment for your unique situation.