Hey guys,
Dentin showing on the chewing surface and at the gum line - not the same thing. On the chewing surface dentin becomes visible when enamel is gone, is usually related to 1 -mechanical trauma - excessive biting forces to this particular tooth (tooth seats higher than the rest of your dentition or some kind of parafunction (grinding, clenching, biting on an objects...), or 2 - chemical trauma - acidic environment in your mouth ( acidic beverages and foods, tobacco/alcohol, acid reflux/bulimia). Your tooth surfaces wearing down from these and exposing dentin definitely need to be fixed, but exposed dentin at the gumline and on the chewing surfaces are absolutely not the same thing. If more than a third of the chewing surface is exposed dentin, the general protocols call for a crown. Exposed dentin only on the chewing surfaces most likely means that you are bruxing (grinding) your teeth against one another. Exposed dentin at the gumline from a chip can occur for many more reasons, but if it is relatively small, it can likely be fixed with a simple filling.