Gaps in Teeth (Diastema): Causes and Treatment Options

Most gaps in adult teeth will not close on their own. The exception is some spacing in children's primary teeth, which may reduce as adult teeth erupt. In adults, teeth naturally drift over time but this rarely closes gaps predictably or in a way that improves alignment. Orthodontic treatment is needed to close gaps deliberately and stably, followed by long-term retention to prevent them reopening.

Gaps have a particular tendency to reopen if retainers are not worn consistently after treatment. This is especially true for diastemas — gaps between the upper front teeth — where the frenum (the soft tissue band above the gap) can also contribute to reopening. A fixed bonded retainer behind the front teeth provides passive long-term retention. Removable retainers worn nightly are also essential to maintain the closed position.

Clear aligners are well suited to closing gaps, particularly single spaces or general mild-to-moderate spacing across the arch. They can move teeth predictably into contact, and the force required to close spaces is within the reliable range of modern aligner systems. Very large spaces, or cases involving bite correction alongside gap closure, may still be better managed with fixed braces, depending on the overall treatment plan.

A gap between the front teeth — called a diastema — can have several causes. Natural tooth size variation, where teeth are smaller relative to the jaw, is common. A thick upper frenum (the tissue between the front teeth and the upper lip) can physically prevent front teeth from meeting. Missing or reduced lateral incisors can also leave space. Some gaps are genetic; others develop due to tongue posture habits or previous tooth loss elsewhere in the arch.

Treatment time depends on the size of the gap and whether the bite also needs adjusting. Small gaps with aligners may close in 6–12 months. More complex spacing involving the bite, multiple gaps, or missing teeth management can take 12–24 months. A clinician can estimate time after a clinical assessment.

Yes — retainers are essential after any gap closure treatment. Gaps have a particular tendency to reopen if retainers are not worn consistently after treatment. A fixed bonded retainer behind the upper front teeth is often recommended specifically for diastema closure to provide long-term passive retention.

NHS orthodontic treatment for under-18s can cover gaps in teeth when the spacing is clinically significant and meets the IOTN grade 4 or 5 threshold. Spacing that causes bite problems or is related to missing or extra teeth is more likely to qualify. Pure cosmetic diastemas — where the only concern is the appearance of a gap between the front teeth — may not reach the NHS threshold and would need to be treated privately. Your dentist can assess the spacing pattern, score it using IOTN criteria, and make a referral if appropriate.