A diastema is the technical term for a space or gap between any two teeth, most often noticed between the two upper front teeth. While some people have a stable gap, a common concern is whether an existing gap can enlarge over time. Numerous anatomical, pathological, and behavioral factors can exert forces that cause the teeth to drift and the space to widen.
Underlying Dental and Skeletal Causes of Gap Widening
A frequent anatomical factor is an oversized or low-attaching maxillary labial frenum, the small fold of tissue extending from the inside of the upper lip to the gum line between the central incisors. If this frenum is thick or extends low enough, it can physically prevent the front teeth from coming together or exert a constant pulling force that actively widens the space. This tissue acts as a source of tension on the teeth.
Another structural cause relates to a mismatch between the size of the teeth and the jawbone. If the jawbone is large relative to the size of the teeth, generalized spacing, including a widened diastema, can occur. Furthermore, the absence or abnormal size of other teeth can significantly influence the front gap. When the lateral incisors are missing or undersized, the pressure balance across the arch is compromised, allowing the central incisors to shift and the gap to increase.
Periodontal disease, or severe gum disease, leads to the destruction of the bone and ligaments that hold the teeth firmly in place. As supportive bone is lost, the teeth become mobile and can migrate, a condition known as pathological migration. This loss of foundational support makes the teeth susceptible to even mild forces, causing a diastema to appear or widen significantly in adults.
Daily Habits and External Forces That Increase Gap Size
Repetitive muscular forces and oral habits apply dynamic pressure that can push teeth apart, enlarging a diastema. One of the most common forces is tongue thrusting, which is an incorrect swallowing reflex. During a normal swallow, the tongue presses against the roof of the mouth, but in a tongue thrust, the tongue pushes forward against the back of the front teeth. This constant, repeated pressure acts like a continual orthodontic force, slowly pushing the front teeth outward.
Prolonged parafunctional habits, especially in older children, can also contribute to space widening. Habits such as thumb sucking, finger sucking, or chronic lip biting exert sustained external pressure on the teeth. These forces interfere with the natural alignment process and can push the front teeth into a more protruded or gapped position.
Chronic teeth grinding or clenching, known as bruxism, introduces intense, non-functional forces that can destabilize the dental arch. While bruxism primarily causes tooth wear and jaw joint issues, the excessive pressure it generates can increase tooth mobility. This high force trauma can weaken the teeth’s attachment, making them more vulnerable to shifting and contributing to the widening of existing spaces.
Professional Interventions for Gap Stabilization and Closure
Addressing a widening diastema requires correcting the underlying cause before or during treatment to ensure stability. Orthodontic treatment is the most direct and effective method for closing a gap by physically moving the teeth. Both traditional metal braces and clear aligner systems apply controlled, gentle forces to shift the teeth into the correct position, eliminating the space. Orthodontics is often necessary for larger gaps or when the teeth also need to be realigned for a proper bite.
For gaps caused by an oversized labial frenum, a minor surgical procedure called a frenectomy is often required. This procedure removes or repositions the restrictive tissue, eliminating the force that is pulling the teeth apart. In children, the gap may close naturally after the frenectomy, but in adults, it is usually followed by orthodontic treatment to fully close the remaining space.
Restorative and cosmetic solutions offer an alternative for small-to-moderate gaps, often when the size or shape of the teeth is a contributing factor. Dental bonding involves applying a tooth-colored composite resin material directly to the tooth surface, which is then sculpted and hardened to widen the teeth and close the space. Porcelain veneers are custom-made shells bonded to the front surface of the teeth, providing a durable and aesthetic way to close the gap and improve the overall appearance of the teeth. Both bonding and veneers are completed much faster than orthodontic treatment.
Regardless of the closure method, the requirement for preventing a gap from widening again is the use of a retention device. Retainers, which can be removable or permanently fixed wires bonded behind the teeth, are worn after treatment to hold the teeth in their new positions. Since teeth naturally want to return to their original position—a phenomenon known as relapse—consistent retention is necessary to stabilize the results and ensure the gap remains closed long-term.