Ever wondered what those little stretchy folds of tissue inside of your mouth are called? They are frenula (singular: frenulum), and while they might seem insignificant, they actually play roles in how your mouth moves and functions. You’re probably familiar with the tongue, but did you know it's anchored to the floor of your mouth by a frenulum? And that's not the only one! Your lips and cheeks also have frenula that affect your smile and oral health.
While they may seem like a minor feature, frenula play roles in oral health, speech, and even growth and orthodontic treatment. Let’s explore what a frenum or frenulum is, the purpose of frenula, and the risks associated with a tight or restrictive frenulum.
What is a Frenulum?
The term "frenulum" or “frenum” refers to a connective tissue band that attaches one part of the mouth to another. In the mouth, frenula can be found in the upper and lower lips (labial frenulum), the tongue (lingual frenulum), and the cheek (buccal frenulum). Their primary purpose is to limit excessive movement of these structures, providing stability during various functions such as eating, speaking, and swallowing.
There are seven common frenula that can be found in the mouth. These include the maxillary labial (lip) frenulum, the mandibular labial (lip) frenulum, the lingual (tongue) frenulum, and four buccal (cheek) frenula.
Frenums typically contain elements that make them small but mighty. They contain epithelial fibers, fibrous connective tissues which contain collagen (a protein that provides strength and support), and elastic fibers which increase resilience and flexibility. Occasionally they will also contain muscle fibers, which aid in movement.
Types of Frenulum
1. Maxillary Labial Frenulum (Upper Lip Frenulum)
The maxillary labial frenulum connects the upper lip to the gum tissue and bone of the upper jaw, just above the front teeth. It originates from the muscle around the mouth and can vary in size and where it attaches. The frenum often shifts away as the first teeth erupt, as the maxillary sinuses develop, and as the jaw grows. It often starts wide and thick in young children, becoming thinner and less pronounced as they develop. In most people, it is relatively small and thin, and does not interfere with the teeth. In some cases, the frenulum can be larger, thicker, and even run in between the teeth. A thicker, more pronounced frenulum can cause issues such as a gap or space between the upper two front teeth (diastema). It can also affect speech and oral hygiene.
2. Mandibular Labial Frenulum (Lower Lip Frenulum)
The mandibular labial frenulum connects the lower lip to the gums below the lower incisors. Like the maxillary labial frenulum, it is typically small and thin. Normally, the frenulum attaches lightly to the gums below the lower incisors (front teeth) and does not interfere with the teeth. In some cases, the frenulum can be thicker or even be situated very close to the teeth. A thicker or more restrictive frenulum may cause discomfort, especially if the lower lip is pulled or stretched frequently, or gum recession. It can also cause issues with the lower lip's ability to move properly, affecting speech and eating.
3. Lingual Frenulum (Tongue Frenulum)
The lingual frenulum is the thin tissue that attaches the base or bottom of the tongue to the floor of the mouth. This frenulum is important for the proper mobility of the tongue, normally allowing for full, unrestricted movement. A tight or restrictive lingual frenulum, commonly referred to as ankyloglossia (or "tongue-tie"), can limit tongue movement. This condition can lead to difficulties with speech, eating, breastfeeding, hygiene, and jaw growth.
4. Buccal Frenula
Buccal (cheek) frenula are present on the sides of your mouth, usually in the area of your premolar teeth. They support and give structure to your cheeks and lips. Most people have one on each side of their mouth, connecting the inside of each cheek to the gums. Some people may have more.
Mandibular Buccal Frenula: These connect the cheek to the lower jaw (mandible) often near the premolars or first molars.
Maxillary Buccal Frenula: These connect the cheek to the upper jaw (maxilla), often near the upper premolars or molars.
Risks of Abnormal Frenum Attachments
Normally, frenula allow for movement of the mouth without presenting any issues. However, sometimes a frenulum is overly tight, restrictive, pronounced, or very close to the teeth. A tight or restrictive frenulum, whether on the lips or tongue, can lead to several oral health and functional issues. These include:
Speech difficulties: Ankyloglossia (tongue-tie) may make it difficult to pronounce certain sounds, resulting in speech impediments.
Limited tongue mobility: Tongue-tie can restrict the tongue’s natural movements, impairing the ability to swallow and eat comfortably.
Breastfeeding problems: In infants, ankyloglossia can interfere with proper latch during breastfeeding.
Tooth eruption problems: The labial frenulum can interfere with normal tooth eruption if it is located too close to the alveolar ridge (bone).
Gaps between teeth: In the case of a prominent maxillary labial frenulum, the tissue pulling on the gums between the front teeth can cause a diastema (space between the teeth).
Poor hygiene: If a frenulum limits the natural movement of the lips or tongue, this may make it harder to clean areas of the mouth, contributing to poor oral hygiene and an increased risk of cavities.
Gum recession: Over time, if a tight or restrictive frenum is attached close to the teeth and pulls too hard, this pressure can lead to gum (gingival) recession. This may expose the tooth root and cause sensitivity.
Misalignment of teeth and bite: A restrictive lingual frenulum can affect growth of the jaws and alignment of the teeth. Ideally, the tongue should rest on the roof of the mouth, helping to guide growth of the upper jaw. In people with ankyloglossia (tongue-tie), the tongue is often positioned low in the mouth. Because the tongue isn't able to sit up high and apply proper pressure to a growing upper jaw, the jaw can become narrow and underdeveloped. This can lead to a high, narrow palate and misaligned bite.
Discomfort and pain: If the frenulum is too tight, it can cause tension or pain during normal activities like speaking or eating, especially in cases where the frenulum interferes with the natural motion of the lips or tongue.
Impact on Orthodontic Treatment
Orthodontic treatment often involves repositioning the teeth and sometimes the jaw to achieve proper alignment. The frenula of the mouth can impact jaw growth, orthodontic treatment options, and results of orthodontic treatment in various ways.
Diastema: A prominent or thick labial frenulum can contribute to a diastema (a gap between the upper front teeth). In some cases, a frenectomy procedure is performed to help release the frenulum, to help prevent the gap from reopening after braces or aligners are removed. Failure to address a restrictive or prominent frenulum may result in recurrence of the diastema after orthodontic treatment.
Tongue Mobility: A restricted lingual frenulum can present significant challenges for orthodontic treatment, particularly for patients who need to use appliances like expanders, retainers, or braces. If the tongue’s mobility is limited, it may affect the patient’s ability to keep the mouth and teeth clean, resulting in an increased risk of cavities, gum disease, and other oral health issues during treatment.
Imbalanced growth: When the tongue is restricted, as in ankyloglossia (tongue-tie), and does not rest in the correct position, it can affect the growth and development of the jaws. Ideally, the tongue rests up on the roof of the mouth, which helps guide the growth of the upper jaw while children are growing. In the case of ankyloglossia, the tongue is restricted and often positioned low in the mouth. Because the tongue isn't able to sit high and apply pressure against the sides of the upper jaw during growth, the upper jaw can become narrow and underdeveloped. This leads to a high and narrow palate. Studies suggest that low tongue posture can also create extra pressure on the lower jaw (mandible), pushing it forward and causing the teeth and bite to misalign. Some studies also show that severe cases of tongue-tie may lead to what is called a Class III malocclusion (misaligned bite), where the lower jaw grows too far forward compared to the upper jaw.
Inflammation and irritation: Orthodontic appliances can sometimes irritate a frenulum that attaches close to the teeth, especially if it's thick or prominent. This can lead to discomfort, ulceration, swelling, and overgrowth of the gum tissue.
Poor oral health: A restricted lingual frenulum can present oral health challenges, especially during orthodontic treatment. If the tongue’s mobility is limited, it can affect a person’s ability to keep their mouth and teeth clean, resulting in an increased risk of cavities and gum disease. If the frenum pulls too hard, it can cause gum recession.
Orthodontic options and results: A restricted lingual frenulum (tongue-tie) is associated with a reduced upper canine width (narrow dental arch), narrow palate, and high-arched palate. These conditions are often associated with overcrowding of teeth, crossbite, a narrow smile, and potentially constriction of the airway. Though they can often be addressed with early intervention in children, options to address conditions like these become more limited and more invasive for adults.
Relapse: Restricted motion of the tongue caused by a restrictive frenulum can lead to altered oral behaviors, such as mouth breathing, improper swallowing, or tongue thrusting. These habits can place unwanted pressure on the teeth. This can lead to orthodontic relapse, in which teeth shift back to their previous positions after orthodontic treatment. Additionally, a tongue that is unable to rest properly against the roof of the mouth can prevent the proper development and growth of the upper jaw. Even after orthodontic treatments such as braces or clear aligners, if the underlying problem isn’t addressed, the tongue can still apply pressure in ways that cause the teeth to shift back to their original positions, leading to treatment results not lasting.
Dr. Danielle Godley, orthodontist and owner at Godley Family Orthodontics, explains that in cases where the frenulum extends between the upper incisors and contributes to a diastema or space between front teeth, she often sees the gum tissue bunch up and appear overgrown during space closure. Dr. Godley says she recommends a procedure to release the frenulum to help not only with hygiene, but also to help prevent the gap from returning after orthodontic treatment. “This is something I think helps ensure healthy teeth and successful results for our patients,” she says.
Types of Frenum Attachments: Classification
The classification of frenum attachments helps healthcare professionals like dentists and orthodontists understand the degree of attachment and its impact on oral function and esthetics. Various systems have been proposed for classifying frenal attachments. These classifications are mainly used in pediatric dentistry, periodontics, and orthodontics.
1. Labial Frenulum
The labial frenulum is classified by its position and location of attachment. The most common classification for this frenum attachment was introduced by Placek in 1974. His team classified frenum attachment based on whether the attachment was located in the mucogingival junction (mucosal), the attached gingiva (gingival), the interdental papilla (papillary), or through the interdental papilla across to the palate (papillary penetrating). Clinically, papillary and papillary penetrating types of frenum are considered as abnormal or pathological.
The Placek classification of the labial frenum is based upon the attachment level of frenal fibers:
Mucosal – most common; when the frenum fibers are attached up to mucogingival junction
Gingival – when frenum fibers are inserted within attached gingiva
Papillary – when frenum fibers are extending into inter-dental papilla
Papilla penetrating – when the frenum fibres cross the alveolar process (bone) and extend up to palatine papilla.
An abnormal frenulum can also be identified by performing a blanching test. This involves pulling the lip and therefore the labial frenum to test for movement of the papilla or blanching (turning white) produced due to ischemia (too much tension or pressure can cause lack of blood flow).
2. Lingual Frenulum
A restricted lingual frenulum is commonly referred to as tongue-tie, or ankyloglossia. Classification of the lingual frenum helps providers understand the severity of tongue-tie and determine the best course of action for intervention. The lingual frenulum is typically classified based on its attachment relative to the tip of the tongue and the floor (base) of the mouth. The two most common classification systems are the Coryllos Classification and the Kotlow Classification.
According to the Coryllos Classification, tongue-ties can be divided into four types, according to how close the frenulum attachment is to the tip of the tongue:
Coryllos Type 1 (Type I)
The lingual frenulum is attached to the tip of the tongue. It is typically thin and elastic, and anchors the tip of the tongue to the ridge behind the lower teeth.
Coryllos Type 2 (Type II)
The lingual frenulum is 2 to 4 millimeters from the tip of the tongue and close to the ridge behind the lower teeth. It is typically thin and elastic.
Coryllos Type 3 (Type III)
The lingual frenulum attaches mid-tongue and to the middle of the floor of the mouth. The frenulum is usually thicker and not as elastic.
Coryllos Type 4 (Type IV)
The lingual frenulum attaches at the base of the tongue. It is typically not visible, but can often be felt by the examiner as tight fibers that are anchoring the tongue. This type is thick, inelastic, and submucosal. It restricts movement at the base of the tongue.
The Kotlow Classification is less common, and focuses more on the tongue length from the tip of the tongue to the frenulum attachment:
Clinically acceptable
Normal, free tongue length > 16 millimeters.
Kotlow Class I: Mild ankyloglossia
The frenum is 12 to 16 millimeters from the tip of the tongue. Slight restriction.
Kotlow Class II: Moderate ankyloglossia
The frenum is 8 to 11 millimeters from the tip of the tongue. Noticeable restriction.
Kotlow Class III: Severe ankyloglossia
The frenum is 3 to 7 millimeters from the tip of the tongue. Significant restriction.
Kotlow Class IV: Complete ankyloglossia
The frenum is less than 3 millimeters from the tip of the tongue. Severe restriction.
In addition to these classifications, an evaluation also considers the tongue's functional ability to move, especially in children. The tongue should be able to protrude without clefting, sweep across the upper and lower lips easily without straining, and should not place excessive force on the front teeth. The lingual frenum should allow a normal swallowing pattern, should not create a diastema between the front teeth, should not interfere with breastfeeding, and should not prevent the tongue from making proper sounds for speech.
Treatment for Restrictive Frenula
In cases where the frenulum is too thick or restrictive, a procedure to release or modify the frenulum can be performed. Removing or modifying the frenulum allows for greater mobility and prevents complications.
Frenectomy vs. Frenotomy
When it comes to treating issues related to the frenulum, such as tongue-tie (ankyloglossia) or lip-tie, two common surgical procedures are frenectomy and frenotomy. While they sound similar, these procedures often have differences in terms of technique and the extent of tissue removal. Both procedures aim to improve function and alleviate discomfort, but they’re used in slightly different circumstances.
What is a Frenectomy?
A frenectomy (sometimes called frenulectomy) is a surgical procedure where the entire frenulum is either partially or completely removed. Depending on the case, a frenectomy can be performed using a scalpel, surgical scissors, or laser surgery. Laser frenectomies are becoming increasingly popular due to their precision, reduced bleeding, and quicker healing time. Regardless of the method used, most patients see improvements immediately.
When is a Frenectomy Needed?
Severe tongue-tie (ankyloglossia): If the lingual frenulum is restricting the tongue’s movement to a degree that it affects breastfeeding, speech, eating, or alignment of the teeth or bite, a frenectomy may be necessary.
Lip-tie: When the labial frenulum is too tight and interferes with proper lip movement, tooth alignment, or causes gum recession, a frenectomy might be performed.
Orthodontic concerns: In some cases, a tight or large frenulum can impact the alignment of teeth. A frenectomy may be recommended to reduce the tension on the gums and teeth, making orthodontic treatment more effective.
What is a Frenotomy?
A frenotomy, on the other hand, is typically a less invasive procedure that involves making a small incision or snip in the frenulum, rather than completely removing it. The goal of a frenotomy is to loosen or release a tight frenulum without completely removing it. A frenotomy is often performed using surgical scissors or a small surgical blade. The incision made is usually minimal, and the procedure is typically quicker than a frenectomy. ‘
When is a Frenotomy Needed?
Mild to moderate tongue-Tie: A frenotomy is often used for infants with mild to moderate tongue-tie, particularly when the restriction of the tongue’s movement is preventing proper breastfeeding but does not require the full removal of the frenulum.
Lip-tie: In cases where a lip-tie is causing minor issues, such as difficulty with breastfeeding or minor speech problems, a frenotomy might be sufficient to improve mobility without needing to completely remove the frenulum.
Less severe orthodontic concerns: If the tight frenulum is not severely affecting the alignment of the teeth but still causing some functional issues (like difficulty with speech or eating), a frenotomy may provide enough relief.
Both frenectomy and frenotomy are important procedures that can help alleviate the problems caused by restrictive frenulums. While they sound similar, the key difference is the extent of the tissue removed. A frenectomy is a more extensive procedure that completely or partially removes the frenulum, while a frenotomy simply makes a small cut to release tension in the frenulum. If you or your child are experiencing difficulties related to a tongue-tie or lip-tie, a visit to a dentist, pediatrician, or orthodontist can help determine which procedure is most appropriate based on the severity of the condition and individual needs.
Conclusion
As you can see, those tiny but mighty folds of tissue known as frena play surprising roles in your mouth. From helping babies latch correctly to influencing your smile and affecting your speech, frenula are definitely worth knowing about. Classification systems and examinations help healthcare professionals, such as dentists and orthodontists, understand the degree of tongue restriction and determine whether intervention is necessary to improve tongue mobility and function.
If you suspect you or your child might have a frenulum that's restrictive or causing problems – whether it's difficulty breastfeeding, speech issues, or gaps between teeth – don't hesitate to discuss this with your dentist or orthodontist. They're the experts when it comes to diagnosing and treating frenulum-related issues. Early intervention with a procedure like a frenotomy or frenectomy can make a world of difference for those that benefit. While these procedures are generally safe, your provider will carefully assess your individual situation and discuss any potential complications with you.
By being aware of your oral frenula and seeking professional guidance when needed, you're taking a proactive step towards a healthier, happier mouth. And that's something to smile about!
Resources:
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American Academy of Pediatric Dentistry. Policy on management of the frenulum in pediatric patients. The Reference Manual of Pediatric Dentistry. Chicago, Ill.: American Academy of Pediatric Dentistry; 2024:73-8.
Mirko P, Miroslav S, Lubor M. Significance of the labial frenum attachment in periodontal disease in man. Part I. Classification and epidemiology of the labial frenum attachment. J Periodontol. 1974 Dec;45(12):891-4. doi: 10.1902/jop.1974.45.12.891. PMID: 4533498.
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ABOUT THE AUTHORS:
Dr. Raina Chandiramani is Orthodontist and Owner at Louisville Orthodontics, serving local communities surrounding Prospect, KY. She blends her extensive training and experience to deliver personalized, cutting-edge orthodontic care to each of her patients.
Dr. Danielle Godley is Orthodontist and Owner at Godley Family Orthodontics. Her office serves the Zionsville, IN and Indianapolis areas. She welcomes both children and adults at her modern orthodontic office.