A diastema is a gap between two teeth, most commonly the upper front teeth. Clinically, any space greater than 0.5 mm between the surfaces of adjacent teeth qualifies. While it’s one of the most common cosmetic dental concerns, a diastema isn’t always a problem that needs fixing. Many people live with one comfortably, and in children, these gaps frequently close on their own.
Where Diastemas Appear and How Big They Get
Gaps can technically form between any two teeth, but the vast majority occur between the two upper central incisors. This specific type, called a midline diastema, is what most people picture when they think of a tooth gap. Dentists measure these spaces using calipers, typically at or just above the biting edge of the teeth.
Not all diastemas look alike. Research published in the Journal of Orthodontic Science categorized midline gaps into five distinct shapes: trapezoidal (44% of cases), triangular (40%), rectangular (12%), inverted triangular (2%), and biconcave (2%). Size varies too. About 18% of diastemas fall between 0.5 and 1 mm, 38% between 1 and 2 mm, and 44% are wider than 2 mm. That largest category, over 2 mm, is where the gap becomes most visible when you smile.
What Causes a Gap Between Your Teeth
Several factors can create or widen a diastema, and often more than one is at play.
The Lip Frenum
The frenum is the small band of tissue connecting your upper lip to the gum above your front teeth. When this tissue is thicker than normal or attaches lower on the gum (closer to or even between the teeth), it can physically prevent the central incisors from coming together. Research confirms that people with diastemas have oversized frenum attachments far more often than people without gaps. Smaller gaps of 2 mm or less tend to coexist with a normal frenum, while larger gaps are strongly associated with the oversized type that extends down into the gum tissue between the teeth.
Tooth and Jaw Size Mismatch
When teeth are naturally smaller than average relative to the jawbone, there’s simply more space than the teeth can fill. This is especially common when the upper lateral incisors (the teeth flanking your two front teeth) are undersized or peg-shaped. The extra room leaves gaps that may appear between multiple teeth rather than just at the midline.
Habits and Muscle Patterns
Certain repetitive behaviors push the front teeth forward or apart over time. Tongue thrusting, where the tongue presses against or between the front teeth during swallowing, is the most significant behavioral factor, present in about 16% of diastema cases in one study. Mouth breathing contributes in roughly 6% of cases by altering the resting posture of the tongue and lips. Thumb sucking plays a smaller role at around 1%, though prolonged pacifier use in early childhood has a similar effect. Even tongue piercings have been linked to diastema development, as the metal stud repeatedly contacts and nudges the front teeth.
Diastemas in Children Often Close Naturally
If your child has a gap between their baby teeth or even their newly erupted permanent front teeth, there’s a good chance it will resolve without treatment. Gaps between the upper central incisors are extremely common in children during the mixed dentition stage, when baby teeth and permanent teeth coexist. Dentists sometimes call this the “ugly duckling stage” because the teeth can look widely spaced and slightly flared.
The key milestone is the eruption of the permanent canine teeth (the pointed teeth next to the lateral incisors), which typically happens between ages 11 and 13. As the canines descend, they push the neighboring teeth toward the midline, naturally closing or significantly reducing the gap. For this reason, most orthodontists recommend waiting until the canines have fully come in before considering any treatment for a midline diastema in a child.
When a Gap Affects More Than Appearance
Most diastemas are purely cosmetic. The teeth function normally, and the gap causes no pain or structural issues. However, larger gaps can occasionally create practical challenges. Some people notice a subtle whistle or lisp when pronouncing certain sounds, particularly “s” and “th,” because the tongue can’t seal against the teeth in the usual way. Food trapping between teeth with significant spacing can also increase irritation of the gum tissue in that area over time.
Whether to treat a diastema comes down to how it affects you personally. Some people consider their gap a distinctive feature. Others feel self-conscious about it or find it functionally bothersome. Neither response is wrong, and treatment is always elective unless there’s an underlying issue like gum disease contributing to the spacing.
Cosmetic Fixes: Bonding and Veneers
For gaps that are primarily a cosmetic concern, two approaches dominate: composite bonding and porcelain veneers. They differ significantly in cost, longevity, and what’s involved.
Composite bonding is the quicker, less invasive option. Your dentist applies tooth-colored resin directly to the edges of the teeth flanking the gap, building them out until the space is closed. The whole process typically happens in a single visit, requires no lab work, and usually doesn’t need anesthesia since no tooth structure is removed. It’s the most budget-friendly cosmetic fix and works well for small gaps and single-tooth touch-ups. The tradeoff is durability: bonding typically lasts 3 to 7 years before it needs repair or replacement. The resin is also more prone to staining and chipping than porcelain.
Porcelain veneers are thin shells custom-made in a dental lab and bonded to the front surface of your teeth. They offer a more natural, polished appearance because porcelain mimics the translucency of real enamel in a way that resin can’t quite match. Veneers resist staining, maintain their color over time, and last 10 to 15 years or longer. The downsides: your dentist needs to remove a thin layer of enamel to fit them, making the process irreversible. They also require multiple visits and cost significantly more than bonding.
Orthodontic Treatment for Larger Gaps
When a diastema is larger than a couple of millimeters, or when spacing exists between multiple teeth, orthodontics is often the most effective route. Both traditional braces and clear aligners can close gaps by gradually shifting the teeth together. Treatment timelines vary depending on the size of the gap and whether other alignment issues are present, but closing an isolated midline diastema is one of the simpler orthodontic corrections.
One important consideration: if the gap was caused by a habit like tongue thrusting, that habit needs to be addressed alongside orthodontic treatment. Otherwise the teeth will drift apart again once the braces or aligners come off. Habit-breaking appliances or tongue posture retraining may be recommended as part of the treatment plan to prevent relapse.
Frenectomy: Removing the Tissue Barrier
When an oversized frenum is the primary cause of a diastema, a small procedure called a frenectomy may be recommended. This involves removing or releasing the band of tissue so it no longer holds the teeth apart. Modern frenectomies are remarkably quick, often performed with a laser. Studies show procedure times as short as 15 to 60 seconds depending on the type of laser used, with recovery limited to minor swelling and discomfort of the upper lip for two to three days.
A frenectomy alone won’t close an existing gap in most cases. It removes the obstacle, but the teeth still need to be moved together, usually with braces or aligners. In children, if the frenum is released before or during the eruption of the permanent canines, the gap may close naturally as the remaining teeth come in. In adults, orthodontic treatment after the frenectomy is almost always necessary to bring the teeth together and hold them in place.