Crown lengthening is a precise gum and bone procedure that exposes more of the tooth. It lets crowns and fillings fit properly, helps keep the gums healthy and can also improve the smile line.

What is crown lengthening?

Despite the name, the tooth itself is not made longer. The gum, and sometimes a small amount of the underlying bone, is reshaped so that more of the existing tooth is exposed. This gives the dentist a stable, clean margin to build a restoration on.

When is it recommended?

• A tooth broken or decayed at or below the gum line that needs a crown
• Too little tooth structure to hold a crown, filling or bridge securely
• A gummy smile caused by excess gum tissue or short-looking teeth
• Uneven gum levels that spoil the appearance of front teeth
• Previous crowns that sit too close to the bone and keep irritating the gum

There is a biological reason for this rule: the gum and bone need space to attach to the tooth. If a restoration invades that space, the gum becomes inflamed and tends to recede. Crown lengthening protects that space.

Planning the procedure

Planning includes a clinical examination, probing of the gum, X-rays, and often a smile analysis with photographs. For cosmetic cases, the planned gum line can be previewed using digital design, a concept we discuss in digital smile design. If gum disease is present, it is treated first so that tissue is healthy before surgery.

How the surgery is performed

• The area is numbed with local anaesthesia.
• The gum is carefully reshaped, or lifted as a small flap, to expose the tooth.
• If required, a small amount of bone is smoothed to restore the proper distance between bone and the planned restoration.
• The gum is repositioned and stitched.
• A protective dressing may be placed.

A laser can be used for soft tissue reshaping in suitable cases, with less bleeding and a more comfortable healing period. See our overview of laser dentistry.