A frenum (also called a frenulum) is a small fold of tissue that connects two structures in your body and limits their range of motion. The most familiar ones are inside your mouth, but frenula exist in other parts of the body too, including the genitalia. Most people first hear the word when a dentist mentions it during an exam or when a newborn has trouble breastfeeding.
Types of Oral Frenula
You have several frenula inside your mouth, each anchoring a soft structure to a fixed one. The three main types are:
- Lingual frenulum: A thin band of tissue connecting the underside of your tongue to the floor of your mouth. You can see it by lifting your tongue toward the roof of your mouth.
- Labial frenulum: Tissue that connects your lips to your gums. The most noticeable ones sit between your two upper front teeth and between your two lower front teeth. You can feel the upper one by pulling your upper lip outward.
- Buccal frenula: Smaller bands running along the sides of your mouth, farther back toward the molars. These support and give structure to your cheeks and lips.
What Frenula Are Made Of
Under a microscope, a frenum is a fold of oral mucosa (the soft lining of your mouth) with layered connective tissue beneath it. The lingual frenulum, the most studied type, contains a high proportion of a flexible protein called type III collagen along with elastin fibers that let it stretch and snap back. The thickness of those elastin layers varies significantly from person to person, which is one reason some people have much tighter frenula than others.
Frenula Outside the Mouth
The word “frenum” applies to similar tissue connections elsewhere in the body. The most commonly discussed is the penile frenulum, a small band on the underside of the penis that connects the foreskin to the head (glans). It serves the same basic purpose as oral frenula: anchoring one structure to another while allowing controlled movement.
When a Frenum Causes Problems
A frenum only becomes a medical concern when it’s too short, too thick, or attached in a position that restricts normal function. The two most common issues involve the lingual and labial frenula.
Tongue-Tie (Ankyloglossia)
When the lingual frenulum is unusually short or tight, it restricts tongue movement. This condition, called tongue-tie, is classified by measuring the length of “free tongue” between the frenulum’s attachment point and the tip of the tongue. A normal range is greater than 16 mm. Mild tongue-tie falls between 12 and 16 mm, moderate between 8 and 11 mm, severe between 3 and 7 mm, and complete tongue-tie is anything under 3 mm.
In newborns, tongue-tie can make breastfeeding difficult because the baby can’t latch properly. In older children and adults, a tight lingual frenulum can affect speech, particularly sounds that require the tongue to reach the roof of the mouth or extend past the teeth.
Labial Frenum and Tooth Gaps
A labial frenulum that attaches too low on the gum, extending between or even behind the upper front teeth, can contribute to a gap (called a diastema) between those teeth. Two specific subtypes of frenum attachment, called papillary and papillary penetrating, are most closely linked to this gap. However, thumb sucking, missing teeth, and other factors can also cause a diastema, so the frenum isn’t always the culprit. In children, dentists typically recommend waiting until the permanent lateral incisors (the teeth on either side of the front two) have come in, because the gap often closes on its own at that point.
How Frenum Problems Are Treated
When a frenum needs to be corrected, there are a few different procedures depending on the goal. A frenectomy removes the frenulum entirely. A frenuloplasty rearranges the tissue rather than removing it, which can be useful when a more precise reshaping is needed. For upper lip ties in particular, the procedure sometimes involves raising a small flap of tissue and removing material between the teeth, which is why an experienced oral surgeon or pediatric dentist typically handles it.
For labial frenula contributing to a tooth gap, current guidelines recommend closing the gap with orthodontics first and performing the frenectomy afterward. Doing it in the opposite order makes relapse more likely.
Laser vs. Traditional Surgery
Frenectomies can be performed with a scalpel or a laser. A meta-analysis comparing the two found that laser procedures resulted in significantly less pain on the first and seventh days after surgery, less discomfort while speaking and chewing, and shorter procedure times. Laser frenectomies also eliminated the need for sutures entirely and produced no bleeding during the procedure in 100% of cases studied. The tradeoff is that laser equipment isn’t available at every dental practice.
What Recovery Looks Like
Recovery from a frenectomy is relatively straightforward. The first few days typically involve noticeable swelling and mild pain, manageable with over-the-counter pain relievers and cold compresses. By the second week, most swelling has subsided and the tissue is healing significantly. Full tissue healing takes about six to eight weeks, though most people feel back to normal well before that.
During recovery, saltwater rinses help keep the area clean and soothe irritation. Sticking to soft foods and avoiding anything hot or spicy minimizes discomfort in the first week. Good oral hygiene is important throughout to prevent infection at the surgical site.