Crown lengthening is a dental surgery that removes gum tissue, and sometimes a small amount of bone, to expose more of a tooth’s surface. It’s done either to save a damaged tooth that needs a crown or to improve the appearance of a “gummy smile.” The procedure is one of the most common periodontal surgeries, and it’s typically performed by a periodontist (a dentist who specializes in gums and the bone supporting your teeth).
Why Crown Lengthening Is Needed
The most common reason is functional: a tooth has broken off at the gumline, or decay has reached so far below the gum that there isn’t enough visible tooth left to anchor a crown. For a crown to stay in place long term, it needs to grip onto solid, healthy tooth structure. The general rule is that at least 4 mm of sound tooth needs to be exposed above the bone. Without that, any crown placed on top is likely to fail, and the tissue around it can become chronically inflamed.
This requirement comes down to something called the biologic width, the roughly 2 mm band of soft tissue that naturally attaches to your tooth just above the jawbone. That attachment acts as a seal protecting the bone underneath. If a crown’s edge sits too close to the bone and encroaches on this zone, the body responds by trying to resorb bone to re-create the space it needs. The result is ongoing inflammation, bone loss, and gum disease around that tooth. Crown lengthening prevents this by moving the bone and gum down, giving the crown enough room to sit without disturbing that natural seal.
The second major reason is cosmetic. Some people have a “gummy smile” where the teeth appear short because excess gum tissue covers them, or the teeth haven’t fully emerged from the bone during development (a condition called altered passive eruption). Aesthetic crown lengthening reshapes the gumline across several front teeth at once, and research shows the results remain stable at least a year after surgery.
What Happens During the Procedure
Crown lengthening is done under local anesthesia, so the area is completely numb. The periodontist starts by making small incisions in the gum tissue and lifting it away from the tooth and bone. This gives direct access to see how much tooth is available and how much bone needs to be adjusted.
In simpler cases, only soft tissue is removed. This is essentially a gingivectomy, trimming away excess gum to reveal more tooth. But in most functional cases, the periodontist also reshapes a small amount of bone around the tooth. This bone recontouring, called ostectomy, is what creates the space needed for that critical 2 mm biologic width plus enough exposed tooth for the crown. The goal is to end up with about 3 mm between the edge of the future crown and the top of the bone.
Once the tissue and bone are at the right level, the gums are repositioned and sutured into place. The entire procedure typically takes 30 to 60 minutes for a single tooth, though it can take longer when multiple teeth are involved.
Recovery and Healing Timeline
Most people feel fine within about a week. The surgical site may be sore for the first few days, and you can expect some swelling and minor bleeding. Eating soft foods and avoiding the area while brushing helps during this initial stretch. Sutures are placed during the procedure to hold the gums in their new position.
The part that surprises many patients is how long they need to wait before getting the permanent crown. While the area feels healed after a week or two, the soft tissue takes about 3 months to fully mature and settle into its final position. For front teeth where appearance matters most, periodontists often recommend waiting 4 to 6 months to ensure the gumline has stabilized before the final restoration is placed. Putting a crown on too soon risks an uneven gumline or a visible margin as the tissue continues to shift.
Risks and Potential Complications
Crown lengthening is a well-established procedure, but it does carry some risks. The most common issue is tissue rebound, where the gums grow back toward their original position during healing instead of staying where they were sutured. This is more likely when the bone is left in an uneven contour after reshaping. If significant rebound occurs, a minor revision may be needed.
Exposing more root surface can also increase tooth sensitivity to hot and cold. The root doesn’t have the same thick enamel covering as the visible part of the tooth, so newly exposed areas may feel more reactive. This usually improves over time, especially once the final crown is placed and covers the sensitive area.
In rare cases, particularly with techniques that involve repositioning a tooth, root resorption can occur, where the body breaks down a small amount of the root tip. There’s also the inherent tradeoff that removing bone around one tooth can affect the bone level on neighboring teeth, potentially creating sensitivity or recession next door.
When Crown Lengthening Isn’t an Option
Not every tooth is a good candidate. The most important factor is the crown-to-root ratio, meaning how much tooth is visible above the bone compared to how much root is anchored below it. A healthy ratio is about 1:2. If a tooth already has a short root, removing bone to expose more crown can leave it without enough support, making it loose or prone to failure. In those cases, extraction and an implant may be the better path.
Other contraindications include teeth that are too damaged by decay or fractures to be restored even with more exposed structure, teeth where the roots of adjacent teeth sit very close together (limiting how much bone can be safely removed), and teeth with deep furcation involvement, meaning the area where a molar’s roots split apart has already lost significant bone. If the procedure would compromise the gums or bone around neighboring teeth, or if the final result wouldn’t leave a tooth that can be maintained long-term, it’s generally not recommended.
Cost and Insurance Coverage
Crown lengthening typically costs between $1,000 and $3,000 per tooth, though prices vary widely depending on location, the complexity of the case, and whether bone removal is needed. Functional crown lengthening, the kind done to save a tooth that needs a crown, is more likely to be partially covered by dental insurance because it’s considered a medically necessary periodontal procedure. Cosmetic crown lengthening for a gummy smile is usually classified as elective and less likely to be covered. Your periodontist’s office can submit a pre-authorization to your insurance to get a clearer picture before you commit.