Crown lengthening is often necessary for the following reasons:
Deep tooth decay underneath the gingival (gum) tissues, thus being inaccessible for the proper restorative dentistry.
A tooth is fractured beneath the gingival tissue creating a need for access.
All of the above conditions dictate that the biologic width not be violated. This simply means there must be a distance of about three millimeters from the surrounding bone to the edge of the dental restoration. If this space is encroached upon by dental restorative material such as fillings or crowns, an ensuing inflammatory process will result. This often explains the red, tender gum tissues present about deeply placed crowns.
Crown Lengthening Lower Anterior