Dental Diastema: Causes, Types and Treatment Options
A dental diastema is the term used for a gap between two neighbouring teeth. The best-known example is the gap between the upper central incisors, known as a midline diastema, but it can occur anywhere in either dental arch, and it is common for several gaps to be present at the same time.
Some people see it as a distinctive feature and do not want to change it. Others have felt uncomfortable with it since adolescence. And there are situations in which the gap is not simply a matter of personal preference, because it may indicate something happening in the mouth that is worth assessing. This article distinguishes between these three scenarios.
What Is a Dental Diastema?
A diastema is a visible gap between adjacent teeth that would normally be expected to be in contact. It may measure less than one millimetre or several millimetres, may be isolated or generalised, and may occur only at the front of the mouth or also in the posterior areas.
The upper midline diastema is the most visible and the most common reason for seeking an assessment, for obvious reasons: it is located right in the centre of the smile.
Is a Diastema Always a Problem?
No. And this is probably the most useful point in the entire article.
A stable diastema, with no associated gum disease, no interference with the bite and no concern for the person who has it, does not require treatment. It does not cause pain, damage neighbouring teeth or worsen simply because it exists. Treating it under these circumstances is an aesthetic decision, which is entirely legitimate, but it is a choice rather than a clinical necessity.
The situation changes in two circumstances.
The first is a diastema that has appeared recently in an adult who did not previously have one. A new gap between teeth that were once in contact means that the teeth have moved, and the reason for that movement is what needs to be investigated.
The second is a diastema caused by an underlying problem, such as a marked discrepancy between tooth size and jaw size, a missing tooth or a habit that applies continuous pressure to the front teeth. In these cases, closing the gap without addressing the cause creates the conditions for it to reopen.
Causes of Diastema
Discrepancy Between Tooth Size and Jaw Size
This is the most common cause and the easiest to understand. If the jaws provide more space than the combined width of the teeth requires, some space remains, and this excess is distributed across the dental arch as one or more diastemas.
It is the opposite mechanism to dental crowding, where the teeth do not fit into the available space and overlap. We have discussed this situation in our article dedicated to dental crowding.
This discrepancy has a strong hereditary component, which explains why a midline diastema often appears in several generations of the same family.
Low-Inserted Labial Frenum
The upper labial frenum is the fold of tissue that connects the lip to the gum above the central incisors. When it is thick and attaches very close to the gum margin, it may sit between the two teeth and make their natural closure more difficult.
This is a genuine cause, but it is less common than popular belief suggests. In most cases, the frenum accompanies a diastema caused by a size discrepancy rather than being the determining factor itself. Only after a careful clinical assessment does it make sense to conclude that treatment of the frenum is necessary.
Small or Missing Lateral Incisors
The upper lateral incisors are among the teeth with the greatest natural variation in shape and size. When they are peg-shaped, meaning narrower and more tapered than usual, additional space remains in the front of the mouth even if the other teeth are well positioned.
Agenesis, the congenital absence of one or both lateral incisors, produces the same effect more markedly. In these cases, treatment involves deciding whether to close the spaces completely through orthodontics or redistribute them to allow replacement of the missing teeth.
Periodontal Disease and Tooth Migration
This is the cause that deserves the greatest attention when a diastema is new.
Each tooth depends on the surrounding bone and periodontal ligament for support. When periodontitis destroys part of that support, the front teeth lose stability and may migrate, tilting forwards and moving apart from one another. The typical sign is a fan-shaped pattern of spaces that gradually develops between the front teeth, often accompanied by mobility.
In this situation, the diastema is the visible consequence of a process taking place in the supporting bone. Treating the gap without treating the disease means carrying out orthodontic treatment on an unstable foundation. We have explained the signs of this condition in our article on periodontitis, as well as the gum recession that often accompanies it in our article on receding gums.
Habits That Apply Continuous Pressure
The tongue applies force to the teeth hundreds of times each day. When swallowing is atypical, with the tongue pressing against the front teeth instead of resting against the palate, this repeated force may gradually push the incisors forwards over the years.
Thumb sucking or prolonged dummy use beyond the age when the permanent teeth begin to erupt can have a similar effect, as can habitual positioning of the lower lip between the teeth. In these cases, correcting the habit is part of the treatment. Otherwise, the gap may reopen.
Diastema in Children: When Is It Normal and When Should It Be Assessed?
During mixed dentition, a gap between the upper central incisors is usually normal and temporary.
When the permanent incisors erupt, they often emerge with a slight inclination and a space between them. As the lateral incisors and later the canines erupt, the pressure they exert helps guide the central incisors into their correct position, and the gap often closes naturally without any intervention. This is a transitional stage of eruption, and most of these diastemas resolve by themselves once the permanent canines erupt.
This does not mean they should never be assessed. It simply means that assessment is used to distinguish what is normal from what is not, rather than to treat every gap that appears.
Situations that deserve attention include a very wide diastema that is unlikely to close by itself, persistence of the space after the canines have erupted, asymmetry between the teeth, suspicion of an unerupted supernumerary tooth between the central incisors and persistent sucking habits. A first orthodontic assessment is recommended at around six or seven years of age precisely to identify these situations early, as we have explained in our article on when to take your child to the dentist.
Consequences Beyond Appearance
In most cases, a diastema does not cause harm. When it does, this usually happens in three main ways.
The first is the bite. Spaces in the front of the mouth can alter the way the dental arches come together, and long-standing occlusal imbalances may affect function and place excessive strain on certain teeth. We have discussed this in our article on the consequences of dental malocclusion.
The second is the gum tissue. In open spaces between the teeth, the interdental papilla is no longer protected by contact between neighbouring teeth and may be more exposed to direct impact from food during chewing, which can cause localised inflammation.
The third, and least common, is speech. Large anterior diastemas may interfere with the pronunciation of sibilant sounds, causing a slight lisp when producing sounds such as “s”.
How Is a Diastema Treated?
The choice of treatment depends on the cause, the size of the gap, the patient’s age and the condition of the teeth involved.
Fixed Orthodontics
Fixed braces remain the most versatile approach, particularly when several gaps are present, when root movement is required or when the diastema forms part of a broader orthodontic problem. They allow precise control of tooth movement and can provide stable results.
Invisible Aligners
In cases of an isolated anterior diastema without significant bite problems, invisible aligners are often a suitable option and are frequently the reason adults seek an orthodontic consultation.
They offer the advantages of discretion and easier oral hygiene, but they also have limitations that should be understood, particularly in more complex movements and situations requiring precise control of the roots. We have written two articles on this subject: one explaining what invisible aligners are used for and another discussing when they are indicated and what their limitations are.
Composite Bonding or Veneers
When the gap exists because the teeth are narrow, increasing the width of the teeth may make more sense than moving them. Composite bonding is conservative, reversible and can usually be completed in a single appointment. Veneers can offer a more stable aesthetic result over time, with the amount of tooth preparation varying according to the technique used.
The limitation lies in proportions. Closing a wide gap using restorative material alone may result in teeth that look disproportionately broad, which is why many cases combine orthodontic treatment to redistribute the space with final restorative treatment to close it.
Frenectomy, When Indicated
When the labial frenum is genuinely acting as an obstruction, surgical removal may be necessary. This is usually carried out in conjunction with orthodontic treatment rather than as an isolated procedure, because removing the frenum alone does not close the gap.
Treat the Periodontal Cause First
When a diastema results from tooth migration caused by loss of periodontal support, the sequence is not negotiable: the periodontal disease must first be stabilised, and only then should any tooth movement be considered. Moving teeth while active inflammation and ongoing bone loss are present can worsen the loss of support.
Can a Diastema Reopen?
Yes, and this is one of the reasons why the retention phase after treatment is just as important as the treatment itself.
Teeth have a tendency to move back towards their previous position, particularly after anterior spaces have been closed orthodontically. Retention, whether fixed or removable, is what helps maintain the result, and in cases of a midline diastema it is often recommended for an extended period. If the original cause was a tongue-pressure habit and the habit remains, the risk of the gap reopening is even greater.
When to Book an Appointment
If the gap between your teeth has appeared recently, has become wider over time or is accompanied by bleeding gums or mobile teeth, it should be assessed without delay. In these cases, the diastema is a sign rather than the underlying problem.
If the diastema has always been present and the only question is whether it is worth treating, an assessment can help determine the cause, whether there are any functional implications and which options may be appropriate in your specific case, including the option of doing nothing.
