Crown Lengthening

Last updated: November 6, 2026·Reviewed by Soo Jin Kim, DDS

Crown lengthening uncovers more of a tooth by reshaping the gum, and often the bone beneath it, so a tooth that is broken or decayed near or below the gumline can be repaired with a crown or filling, or so teeth hidden by extra gum show their natural length. Functional crown lengthening exposes enough sound tooth for a restoration to grip and seal against. Esthetic crown lengthening levels the gumline and reduces a "gummy" smile when gum tissue covers more of the teeth than usual. It is done under local anesthetic, and the gum is given several weeks to several months to settle before the final restoration is placed. Crown lengthening is part of the periodontal care at ConfiDental in Carlstadt, and the crown or filling that follows is part of Dr. Kim's restorative care.

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Dr. Lee, our board-certified periodontist, does crown lengthening at our Carlstadt office.

Sung Min Lee, DDS

Overview

Functional crown lengthening is used when too little healthy tooth shows above the gum to restore it well. The tooth may be broken or decayed at or below the gumline, worn or fractured until it is too short to hold a crown, or carry an old filling or crown edge that sits too close to the bone. Exposing more sound tooth gives access to the decay or fracture and lets the edge of the new restoration sit on healthy tooth. A commonly cited restorative target is a ferrule of about 1.5 to 2 mm, a collar of sound tooth that the crown wraps around, and crown lengthening is often performed when a tooth falls short of it.

Esthetic crown lengthening is usually done on the upper front teeth. Teeth can look short when gum tissue covers more of them than usual, a pattern called altered (or delayed) passive eruption, or when the gum has overgrown. Removing the extra gum, and reshaping the bone where it sits too close to the edge of the enamel, shows more of each tooth and can even out the gumline across the smile. A gummy smile can also come from a highly mobile upper lip or from the way the upper jaw grew, and those causes are managed with other treatments, such as lip repositioning surgery for a mobile lip. Treatment depends on the underlying cause, and some people need more than one approach.

The technique depends on how much firm gum surrounds the tooth, how far the bone sits from the planned gum edge, the length of the roots, and the neighboring teeth. When there is enough gum and at least 3 mm between the planned gum edge and the bone, a gingivectomy, trimming away the extra gum, may be all that is needed. When the bone sits closer than that, or the band of firm gum is narrow, the gum is lifted as a flap, the bone is reshaped, and the gum is secured at a lower level (an apically positioned flap with or without osseous surgery). For a front tooth broken below the gumline, orthodontic extrusion, which gently moves the tooth down out of the bone, may be used to protect the gum between the neighboring teeth, sometimes followed by a smaller surgical step.

Crown lengthening prepares a tooth for its restoration, and the crown or filling is a separate step that follows once the gum has healed. During healing the gum edge tends to grow back slightly toward the biting edge, mostly in the first three months, so the final restoration is usually placed after the new gumline has settled. Pocket reduction surgery for gum disease uses similar surgical steps for a different purpose: it shrinks deep, infected gum pockets, where crown lengthening exposes more tooth.

When It's Recommended

A tooth broken or fractured at or below the gumline, with too little tooth showing above the gum to hold a crown or filling
Decay that extends below the gumline and needs to be exposed before the tooth can be restored
A tooth too short to hold a crown securely after wear, decay or a fracture, where more height and a ferrule are needed
A filling or crown edge that sits too close to the bone and encroaches on the gum attachment (biologic width)
A perforation in the upper third of the root that needs to be reached for repair
Teeth that look short because gum tissue covers more of them than usual (altered passive eruption), contributing to a gummy smile
An uneven gumline across the front teeth
Front teeth too short for orthodontic brackets or aligners to be placed in the ideal position

What are the risks of Crown Lengthening?

When to Avoid

A tooth that cannot be restored because of extensive decay or a root fracture
Roots too short for the bone removal needed, which would leave an inadequate crown-to-root ratio
Advanced furcation involvement, bone loss in the area where the roots of a back tooth divide
Bone removal that would compromise the support or appearance of the neighboring teeth
Excess gum display caused mainly by a highly mobile upper lip or by downward growth of the upper jaw, which crown lengthening alone does not correct (esthetic crown lengthening)

Possible risks

Discomfort and bleeding at the surgical site after the procedure
Infection, at a risk comparable to other surgical procedures
Tooth sensitivity to hot and cold, which typically eases over time
The treated tooth looking longer than the neighboring teeth
The tooth feeling looser after bone is removed, and a less favorable crown-to-root ratio
Regrowth (rebound) of the gum edge toward the crown during healing, which can reduce the tooth structure gained
Loss of bone and gum attachment around the treated tooth, which can also affect the neighboring teeth
Furcation involvement, exposure of or bone loss in the area where the roots of a back tooth divide
An uneven gumline in esthetic cases, which may need a second, touch-up procedure
Greater difficulty placing a dental implant later if the tooth is eventually lost
Problems with the crown placed afterward over time, such as chipping, repeated loosening, or decay at its edge

Who needs extra care

Certain heart conditions, such as a prosthetic heart valve or a history of infective endocarditis, call for antibiotic prophylaxis before procedures that manipulate the gum tissue
A front tooth broken or decayed below the gumline, where removing bone would affect the gum between the neighboring teeth, may first be moved down with orthodontic extrusion (forced eruption), sometimes followed by a smaller crown lengthening procedure
A narrow band of firm (keratinized) gum, which is generally preserved by moving the gum toward the root as a flap, since trimming it away (gingivectomy) would leave too little
Orthodontic treatment in progress or planned, where crown lengthening is timed before, during or after braces or aligners depending on the crown height and the restorative plan, and is often done after the braces come off to avoid a second, touch-up procedure

What to Expect During Treatment

An examination and x-rays check your tooth, the gum around it and the level of the bone, and confirm that the tooth can be restored
Any other needed treatment, such as fillings, root canal treatment or a cleaning, is usually completed first
For front teeth, the planned gumline may be mapped out in advance, sometimes with a surgical guide made from a digital smile design
Your tooth and the surrounding gum are numbed with a local anesthetic, and a sedative is sometimes offered as well
Where only gum needs to be removed, the extra gum is trimmed to the planned level
Otherwise, the gum is gently lifted as a flap, the area is cleaned, and the bone is reshaped according to the treatment plan
The gum is placed at its new level and stitched in place, and the site may be covered with a protective dressing
The procedure often takes less than an hour, depending on how many teeth are treated and whether bone is reshaped
Written aftercare instructions are provided, and pain medicine may be prescribed
After about one to two weeks, any remaining dressing is removed and the site is checked
Once the gum has settled, your tooth is prepared and the final crown or filling is made and placed, with a temporary crown protecting it in the meantime if needed

How does Crown Lengthening work?

The gum attaches to each tooth along a band of about 2 mm just above the bone, known as the biologic width or supracrestal tissue attachment. When a filling or crown edge is placed into that band, the body tends to re-create the space by resorbing bone, a process believed to often lead to chronic gum inflammation and bone loss. Crown lengthening moves the gum margin, and the bone when needed, toward the root, so the edge of the restoration can sit on sound tooth with that attachment left intact.

A gingivectomy or gingivoplasty removes and shapes excess gum only, using a scalpel, electrosurgery or a laser. It suits a tooth with a generous band of firm (keratinized) gum and at least 3 mm between the new gum edge and the bone; where the bone is closer, bone reduction is added.
An apically positioned flap lifts the gum away from the tooth so the root and bone can be seen. The bone is reshaped, either by removing some of the bone that supports the tooth (ostectomy) or by thinning and contouring it without removing support (osteoplasty), and the gum is stitched back at a lower level. Shaping the bone into a smooth, scalloped outline helps the gum heal with shallow pockets, while a reversed outline is associated with more regrowth of gum during healing.
The gum edge keeps moving for a while after surgery. In wound-healing studies, the soft tissue above the bone regrows by an average of about 3 mm toward the biting edge, which takes at least three months to complete, and the regrowth is more pronounced with thick gum tissue and varies between people. The final crown or filling therefore usually waits until the gumline has stabilized.
The surgery and the restoration that follows it both happen at our Carlstadt office. Dr. Sung Min Lee, a board-certified periodontist, does the crown lengthening, reshaping the gum and, where needed, the bone. Once the gumline has settled, the crown or filling is part of the general and restorative care Dr. Soo Jin Kim provides.

Recovery & Aftercare

Soreness after surgery is usually managed with over-the-counter pain relievers such as ibuprofen or acetaminophen, and stronger pain medicine or antibiotics are sometimes prescribed
An ice pack on the face for the first few hours, 20 minutes on and 20 minutes off, is commonly advised, with moist heat a couple of days later
Rinsing gently with salt water two to three times a day for the first three to four days, eating soft foods, and brushing and flossing every tooth except the surgical site help the area heal
Avoiding strenuous activity for two to three days, smoking for at least 7 to 10 days, drinking through straws, and hard, sticky or spicy foods, nuts and small seeds protects the healing gum
A protective dressing, if one was placed, usually stays on for one to two weeks
Most people resume normal activities as the gum heals, and full healing commonly takes about three months
The final crown or filling is commonly placed about 6 to 8 weeks after surgery, and 3 to 6 months later in esthetic cases, because the gum can keep changing slightly over that time
Regular dental checkups after the final restoration help keep the tooth and gum healthy, and regular attendance was associated with fewer problems in a long-term study of teeth crowned after crown lengthening
If bleeding does not settle, or swelling or pain gets worse after the first few days, contact the dental office that did the procedure

Alternative Treatments

Orthodontic extrusion (forced eruption), which gently moves the tooth down out of the bone with orthodontic force, alone or with a smaller surgical step, often for front teeth
Surgical extrusion, which repositions the tooth higher in its socket, for some teeth with deep fractures or decay
Extraction and replacement with a dental implant or bridge, when crown lengthening would leave an unfavorable crown-to-root ratio or harm the neighboring teeth
Lip repositioning surgery for a gummy smile caused by a highly mobile upper lip

What the Research Says

Clinical crown lengthening exposes sound tooth structure for a restoration by moving the gum margin toward the root, with or without removing some of the supporting bone[4]
Altered passive eruption, where the gum edge stays over part of the tooth's crown, is one of the two major soft-tissue causes of a gummy smile, and esthetic crown lengthening is the established surgical treatment for it[10]
A systematic review of crown lengthening done before a restoration reported an average gain in crown length of 1.4 to 3.3 mm at 6 months[6]
In a 2026 study of 179 teeth crowned after crown lengthening, an estimated 96.8% were still in place after 5 years and 95% after 10 years[9]
A review of wound-healing studies advises waiting at least three months, and up to six months where appearance matters most, before starting the final restoration while the gum margin settles[5]

About Our Clinicians

Sung Min Lee

DDS

Performs crown lengthening to expose more tooth structure for a crown or other restoration.

Board-certified periodontist specializing in gum disease treatment and dental implant surgery

Full profile

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“Thank you to the entire staff for so many perfect visits.”

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Frequently Asked Questions

What is crown lengthening?

Crown lengthening reshapes the gum, and often the bone beneath it, to uncover more of a tooth. It is done so a tooth broken or decayed near or below the gumline can hold a crown or filling, or so teeth that look short under extra gum show their natural length and the gumline looks even. The crown or filling itself is placed later, once the gum has healed.

Does crown lengthening hurt?

The tooth and gum are numbed with a local anesthetic before the procedure starts, and a sedative is sometimes offered as well. Soreness afterward is usually manageable with over-the-counter pain relievers such as ibuprofen or acetaminophen, and stronger medicine is sometimes prescribed. The tooth may be sensitive to hot and cold for a while, which typically eases over time.

Is crown lengthening safe?

Crown lengthening is one of the most common periodontal surgical procedures and is carried out under local anesthetic. A 2023 meta-analysis of controlled clinical trials concluded that the gum and bone around treated teeth remain stable over time. An examination and x-rays beforehand check that the tooth can be restored and that its roots and neighboring teeth can support the change.

How long after crown lengthening can a crown be placed?

Waiting periods vary with the technique and the location of the tooth. One university dental clinic schedules the final restoration about 6 to 8 weeks after surgery, and 3 to 6 months later in esthetic cases. A review of wound-healing studies advises waiting at least three months, and up to six months where appearance matters most, while the gum margin settles. A temporary crown can protect the tooth in the meantime.

What happens during crown lengthening?

After your tooth and the gum around it are numbed, the gum is either trimmed to the planned level or gently lifted as a flap so the bone beneath it can be reshaped. The gum is then stitched at its new, lower level, and a protective dressing may be placed. The procedure often takes less than an hour, and any dressing is removed after about one to two weeks.

Who is not a candidate for crown lengthening?

Crown lengthening is generally not suitable for a tooth that cannot be restored because of extensive decay or a root fracture, or when the bone removal needed would leave too little root in the bone for the length of the tooth. Advanced bone loss where the roots of a back tooth divide, or a risk to the support of the neighboring teeth, can also rule it out. In those cases, extraction and replacement with an implant may be considered.

Can crown lengthening fix a gummy smile?

Crown lengthening can correct a gummy smile when the cause is gum tissue covering more of the teeth than usual, a pattern called altered passive eruption. Excess gum display can also come from a highly mobile upper lip or from the way the upper jaw grew, and those causes call for other treatments, such as lip repositioning surgery for a mobile lip. Finding the cause first shows which approach fits.

Who places the crown after crown lengthening?

Crowns are part of the restorative care Dr. Kim provides, and Dr. Lee, our board-certified periodontist, performs the crown lengthening that comes before. Between the two steps the gum is given time to settle, which lets the edge of the crown sit on sound tooth at the new gumline.

Sources & References

This article draws from 11 peer-reviewed sources.

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