First, a “gummy smile” isn’t really a technical term and doesn’t have any one specific definition. Most dentists consider a smile “gummy” when 4 mm or more of gum tissue shows above the top of the front teeth when a person is smiling. That said, it can be very different between people when a smile is considered “natural” and when it is considered “gummy”. A big part of it is the ratio between the size of the teeth, lips, and gum tissue showing. Many people consider a gummy smile a big cosmetic issue. Good news though! There are definitely some things that can be done to correct a gummy smile in most people!
There are several reasons why people have gummy smiles and each is treated differently.
Reason #1: Teeth that are too small or haven’t erupted far enough
When teeth are first coming into your mouth (erupting) they usually push through to a certain point and then stop moving. The gum tissue then moves upwards throughout the course of early adulthood. In some people the teeth don’t erupt fully. This makes them look small. In most of these cases, the best option is what is known as “crown lengthening” surgery done by a periodontist. During this type of surgery the periodontist removes several millimeters of bone around most of the front teeth. Because there already was excess bone around the teeth, this doesn’t compromise the support of the tooth at all. Once the bone is removed, the gum tissue also shrinks back. You are able to see the entire “crown” of the tooth finally which usually has a more natural shape.
Reason #2: Worn teeth
Many people develop worn teeth over the course of their life as a result of grinding or acid erosion. When the teeth become worn they also move downwards bringing the gum tissue and bone down with them. This creates a much bigger ratio of gum tissue to tooth resulting in a gummy smile. The best course of action in these cases is to use braces to move the teeth back up to where they should be and then placing crowns on them to restore their correct size and shape.
Reason #3: Lips that are too short
Some people simply have an upper lip that is too short. Of all the reasons for a gummy smile, this one is the most difficult to treat effectively. It’s hard to make a short lip any longer. Some of the previous treatment options can be used to correct it slightly (when appropriate) but for the most part, these are difficult to treat fully.
Reason #4: Lips that move too much when smiling
As opposed to a short lip, some people have lips that move way too much! This is known as lip hypermobility. When they smile, the muscles pull the lips back way further than most people do. The best solutions for lip hypermobility is botox injections (to paralyze some of these muscles) or surgery to correct some of the muscle attachment issues. It is usually best to see a periodontist first for options with this.
Reason #5: An upper jaw that is too long
Some people have good proportions of their lips and teeth but have a face that is simply too long. This is technically known as maxillary vertical excess. The solution for this is jaw surgery in combination with an orthodontist and oral surgeon. The actual surgery is pretty rough. The surgeon breaks the upper jawbone (maxilla) and resets it in a better position. You are usually wired shut for 6 weeks following surgery and this is then following by additional orthodontics.