Teeth serve multiple essential functions, including aiding in digestion, contributing to aesthetic appearance, enabling clear speech, and facilitating smiles. The ideal positioning and shape of a tooth are crucial for optimizing its functions. Specifically, when it comes to the aesthetics of a smile, the visible portion of the tooth within the oral cavity, known as the crown, must possess an ideal length. Any deviation from this ideal crown length, whether it’s too long or too short, can negatively impact the quality of one’s smile and compromise its overall aesthetic appeal. Such alterations can erode a person’s confidence and lead to discomfort during social interactions and conversations.

What is Crown lengthening?

Crown lengthening is a dental procedure that involves the deliberate modification of the visible portion of a tooth, known as the clinical crown, by reducing the amount of gum tissue that is visible in the oral cavity. This procedure gives a beautiful smile, enhances the aesthetic profile of the patients, and provides ease in maintaining oral hygiene.
However, it’s crucial to note that while increasing the length of the clinical crown, the dentist must pay close attention to preserving the ideal biological width. Dentistry uses the term “biological width” to describe the natural separation between the tooth’s supporting structures, including gum tissue and bone.

What is Biological Width?

Biological width is an important physiological landmark of the tooth, which describes the area of tooth-supporting structures. It maintains the health of the tooth and keeps the tooth in the socket. If any dental anomaly or surgical procedure violates the normal biological width of the tooth, the respective tooth will develop mobility and periodontal infection.
Maintaining this ideal biological width during crown lengthening is essential to ensure the long-term health and stability of the tooth and surrounding tissues.¹.

Indications of Crown lengthening

Crown lengthening is recommended for specific dental indications, which can be categorized as follows:

Restorative Indications:

Increased Clinical Crown Loss due to Caries:

Crown lengthening is necessary when caries treatment removes part of the tooth, leaving a clinically short crown unsuitable for dental restoration, such as an artificial crown.
Increased crown length will give more surface area to the restoration for retention.

Fracture or Wear:

In cases where a tooth has been fractured or worn down, crown lengthening is employed to expose more of the tooth structure, facilitating the placement of restorations like crowns or fillings.

Relocating the Impinging Margin of Restoration:

In situations where the margin of dental restoration encroaches on the biologically essential space between the gum line and bone, crown lengthening is performed to reposition the margin at a safe distance from the bone.

Esthetic Indications:

Uneven Gingival Margin:

Crown lengthening can enhance the symmetry of the gingival (gum) line by carefully reshaping the gums, creating a more balanced and aesthetically pleasing appearance.

Short Teeth:

When teeth appear shorter than desired, crown lengthening can expose more of the tooth structure, making the teeth appear longer and more proportionate.

Gummy Smile:

Typically, the gums extend to cover approximately half of the tooth structure, which we term the root portion. The portion of the tooth that is visible within the oral cavity is known as the clinical crown.
However, in certain cases, an increased amount of gum tissue coverage can lead to a decrease in the length of the clinical crown. This condition is called a gummy smile.² It is because when such a patient smiles, there is abnormally excessive gum tissue over the teeth. This problem creates functional and aesthetic difficulties for the patients³.
To overcome these difficulties, patients with gummy smiles undergo the crown lengthening procedure. The procedure increases the clinical crown’s length, enhancing patients’ smiling patterns and aesthetics. It also reduces gum coverage over the teeth, making oral hygiene easier to maintain and improving overall comfort with appearance. By decreasing the extent of gum tissue, a common site for plaque accumulation, you can also lower the likelihood of plaque formation. Plaque is a thin film consisting of food remnants, bacteria, and saliva.

gummy smile as an indication of crown lengthening

Ways to Achieve Crown Lengthening

There are multiple ways to achieve normal clinical crown length. The most common are

Orthodontic or surgical extrusion

In extrusion, orthodontists use orthodontic appliances to forcefully extrude the tooth, increasing the height of the clinical crown as one way to achieve this. In this way, patients have to wear orthodontic appliances for a specific period to favor tooth extrusion.
Alternatively, a periodontist or oral surgeon performs surgical extrusion. It involves surgically exposing more of the tooth’s root structure by reshaping the bone and, if necessary, removing excess gum tissue. The tooth is then physically extruded from its socket to the desired position. Surgical extrusion is employed when more substantial changes to the tooth’s position are required.⁴.[/mfn]

Apical repositioning flap

Apical flap repositioning is a surgical technique used in crown lengthening procedures. In this method, the periodontist or oral surgeon makes an incision near the tooth’s root, lifting a portion of the gum tissue to access the underlying bone. After reshaping the bone and removing excess gum tissue to expose more of the tooth’s surface, the dentist repositions and sutures the flap. This technique improves the aesthetic appearance of the smile, ensures proper tooth restoration, or addresses periodontal concerns.

Gingivectomy

A periodontist performs a gingivectomy to increase the height of the clinical crown by removing gum tissue from the gingival area. This procedure is normally completed in a single sitting.
All these methods have indications and contraindications. To find which method suits your patient, it is necessary to first look at the patient’s aesthetics, the cause of gum enlargement, the extent of tooth damage, and the health of adjacent teeth.

Choosing the right Technique

The periodontist will consider several factors to determine the ideal technique for you. Some of them are:

Aesthetic Goals: Your desired aesthetics and how you want your smile to look are primary factors influencing the choice of technique for crown lengthening.
Crown-to-Root Ratio: The ratio of visible crown to hidden root impacts the choice of technique.
Root Position and Appearance: Your dentist will also consider the location and appearance of the tooth’s root.
Tooth Position Along the Gum Line: Whether your teeth are positioned too high or too low along the gum line will impact the selection of the surgical approach for crown lengthening.
Purpose of the Procedure: In addition to the above-mentioned factor, the purpose of the procedure is also an important determinant. Whether it’s for restoration or periodontal issues impacts the choice of technique.

These factors collectively inform the periodontist’s choice of technique to achieve the desired outcome in crown lengthening procedures.

Steps of the crown lengthening procedure

The most common method for crown lengthening is an apical repositioning flap⁵.In the procedure, the periodontist will follow a set of steps to achieve the desired outcome:

Preparation for Crown lengthening:

Before the crown lengthening procedure begins, the dentist will take several essential steps to prepare the patient and the operative site:

Maintaining Oral Hygiene

Before the procedure, it is crucial for the patient to maintain excellent oral hygiene practices through thorough brushing and flossing. This helps establish a clean and conducive oral environment for the procedure.

Site Isolation

Next, the periodontist employs rubber dams or cotton balls to isolate the working area. This isolation enhances visibility and precision during the operation.

Marking the Incision Area

To indicate the area for the incision, the surgeon will mark the incision with an indelible pencil. This marking is crucial for achieving precision during the procedure.

The Procedure:

Precise Incision:

The periodontist will make a sharp, precise incision over the marked area, ensuring it is situated precisely over the bony surface. After making the incision, the soft tissue flap is elevated carefully and gently to prevent damage or tearing. Once elevated, the periodontist will remove excess gum tissue and contour the underlying bone using specialized bone files.

Meticulous Flap Repositioning:

The periodontist will meticulously reposition the flap over the root area, ensuring proper alignment to increase the clinical crown length and facilitate the healing of the injured tissue.

Suturing:

After the flap repositioning, the dentist will secure the flap in its new position by suturing. The most commonly used sutures are silk sutures.⁶

Post-op and Recovery:

During crown lengthening, the dentist uses local anesthesia to numb the soft tissue, ensuring a pain-free procedure for the patient. However, after the procedure, when the effects of the local anesthesia wear off, patients may experience significant discomfort and pain. To alleviate this pain, the dentist will prescribe ibuprofen or acetaminophen to patients. After the surgery, patients should attend regular follow-up appointments to enable the periodontist to monitor the healing and recovery progress of the treated tissue.

After-care Instructions:

The type of aftercare will depend on the technique, so your dentist will advise you on what to do during your recovery. The post-op instructions include:

Take your prescribed pain medications timely.
Using Cold compresses can address swelling and minor bleeding that patients may experience.
The doctor will normally remove the sutures after a two-week period.
During the recovery period, the patient should take a soft diet and maintain meticulous oral hygiene with the daily use of mouthwash⁷. Chlorhexidine-containing mouthwash reduces the bacterial loads of the operating site and promotes healing.

All in all, crown lengthening is a dental procedure aiming to increase the length of a clinical crown. Whether addressing issues related to aesthetics, restorative dentistry, or periodontal health, this technique offers a versatile solution.

Refrences

1
Lanning, S. K., Waldrop, T. C., Gunsolley, J. C., & Maynard, J. G. (2003). Surgical crown lengthening: evaluation of the biological width. Journal of Periodontology, 74(4), 468–474. https://doi.org/10.1902/jop.2003.74.4.468
2
Aroni, M. A. T., Pigossi, S. C., Pichotano, E. C., de Oliveira, G. J. P. L., & Marcantonio, R. A. C. (2019). Esthetic crown lengthening in the treatment of gummy smile. The international journal of esthetic dentistry, 14(4), 370–382.
3
Alhumaidan, A., Al-Qarni, F., AlSharief, M., AlShammasi, B., & Albasry, Z. (2022). Surgical guides for esthetic crown lengthening procedures: Periodontal and prosthetic aspects. Journal of the American Dental Association (1939), 153(1), 31–38. https://doi.org/10.1016/j.adaj.2021.07.005
4
Cordaro, M., Staderini, E., Torsello, F., Grande, N. M., Turchi, M., & Cordaro, M. (2021). Orthodontic Extrusion vs. Surgical Extrusion to Rehabilitate Severely Damaged Teeth: A Literature Review. International journal of environmental research and public health, 18(18), 9530. https://doi.org/10.3390/ijerph18189530
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Kalsi, H. J., Bomfim, D. I., Hussain, Z., Rodriguez, J. M., & Darbar, U. (2020). Crown Lengthening surgery: An overview. Primary Dental Journal, 8(4), 48–53. https://doi.org/10.1308/205016820828463870
6
Koyuncuoglu CZ, Yaman D, Kasnak G, Demirel K. Preference of Suture Specifications in a Selected Periodontal and Implant Surgeries in Turkey. Eur J Dent. 2019 Feb;13(1):108-113. doi: 10.1055/s-0039-1688732. Epub 2019 Jun 6. PMID: 31170760; PMCID: PMC6635974.
7
Sarfati, A., & Tirlet, G. (2018). Deep margin elevation versus crown lengthening: biologic width revisited. The international journal of esthetic dentistry, 13(3), 334–356.

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Crown Lengthening: Enhancing Your Smile and Oral Health

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