I see these quite often. They vary in size and can be seen on anywhere from just one or two teeth to as many as all the teeth in the mouth. We dentists often call them “abfractions” (I promise not to use that word again).
Chewing pressure on teeth causes flexing and stress to concentrate on the area of the tooth where the “white” enamel of your tooth (the part you normally see) and the root of a tooth meet. Abnormally heavy forces on a tooth can result in the loss of tooth substance at these high stressed areas looking like a wedge cut out at the gumline of the tooth. Many people have tooth clenching and grinding habits (often caused by poorly positioned teeth) and sometimes are unaware of this habit that puts abnormal stress forces on teeth. Heavy wear on the biting surface of teeth can also be a result of these “chewing” habits.
There are other factors that can exacerbate the formation of these notches. Excessively heavy tooth brushing on these vulnerable teeth is one. “Corrosion” in the form of an acid environment in the mouth promotes and accelerates tooth loss in these stressed areas. People with GERD (gastro esophageal reflux- many people are already being treated for that- think heartburn…) or those with diets including carbonated beverages (even diet pop- very acidic) or a lot of acidic foods such as mangoes, citrus or similar fruits can have dramatically deeper notches as well as other signs of acid wear on their teeth. I see quite a bit of that today too. Even your occupation can be a factor. Industrial gases released in the fabrication of many products from batteries to soft drinks can result in corrosion (chemical wear) of teeth and contribute to notching.
So, there are many factors that come in to play as to the cause. The resulting notches can be minor or severe. I have seen them cause the nerve of a teeth to die and root canal treatment is required to save them. So we try to repair these areas with bonded composite (white) fillings to prevent sensitivity, nerve death and the weakening of any teeth involved. We also try to discover different factors that help develop the grooves and try to prevent further damage. Treatment can involve the need for diet change and possibly a dental appliance – “nightguard”- to take the stress off the teeth from grinding habits.