Can Crooked Teeth Cause Speech Problems?

Do Crooked Teeth Affect Speech?

Crooked teeth and certain bite problems can affect speech in some people, but not everyone with misaligned teeth will develop a speech difficulty. Speech depends on precise coordination between the tongue, lips, teeth, palate, jaw and airflow. If the position of the teeth or jaws significantly changes the space available for the tongue or the way air passes through the mouth, particular speech sounds may be distorted.

The relationship is strongest with certain types of malocclusion, particularly an anterior open bite, rather than simply having one or two mildly crooked teeth. Research also shows that people can often adapt their tongue position and speech to compensate for unusual tooth positions.

If tooth or jaw alignment appears to be contributing to a speech problem, a specialist orthodontic assessment can establish whether there is a structural issue that could reasonably benefit from treatment. Some patients may also need assessment by a speech and language therapist because orthodontics and speech therapy address different parts of the problem.

How Do Teeth Help Us Speak?

Teeth do much more than bite and chew food. They also form part of the system used to create speech sounds.

For many consonants, the tongue or lower lip must approach or contact the teeth while air is directed through a very specific space. Even small changes in tongue position or airflow can alter how a sound is produced.

Examples include:

• /s/ and /z/: require precisely controlled airflow between the tongue and the front teeth
• /t/ and /d/: involve the tongue contacting the area immediately behind the upper front teeth
• /f/ and /v/: involve contact between the lower lip and upper front teeth
• “th” sounds: require the tongue to interact closely with the front teeth
• /l/, /n/ and some other consonants: depend partly on accurate tongue placement against the teeth and palate

This helps explain why significant changes in front-tooth position can sometimes influence articulation.

Does Every Person With Crooked Teeth Have Speech Problems?

No. Most people with mild crowding, rotated teeth or small gaps speak completely normally.

The human speech system is highly adaptable. The tongue and lips can often compensate for differences in tooth position, which means the severity of crooked teeth does not necessarily predict the severity of a speech problem.

A longstanding review from Bristol Dental School found that although certain dental irregularities are associated with speech disorders, there was no definitive evidence that simply changing tooth position would automatically improve articulation.

More recent research supports a similar cautious conclusion: particular malocclusions are associated with speech sound differences, but the relationship is complex and is not necessarily straightforward cause and effect.

Which Bite Problems Are Most Likely to Affect Speech?

Anterior Open Bite

An anterior open bite occurs when the upper and lower front teeth do not meet when the back teeth are together.

This is one of the malocclusions most consistently associated with articulation differences in children.

The open space between the front teeth can alter both tongue placement and the direction of airflow. Some people also place the tongue between the front teeth during speech or swallowing.

This may contribute to distortion of sibilant sounds such as /s/ and /z/, sometimes producing an interdental or frontal lisp.

A 2025 review of research involving children found anterior open bite to be the malocclusion most frequently associated with speech sound disorders.

Large Overjet and Class II Malocclusion

A large overjet means the upper front teeth project substantially further forwards than the lower front teeth.

Changes in the relationship between the lips, tongue and front teeth can influence certain speech sounds in some patients, although a large overjet does not automatically produce a speech disorder.

Prominent upper teeth can have other clinical implications too, particularly in children because they are more vulnerable to traumatic injury. Glow Dental provides early orthodontic assessment for selected developing bite problems.

Underbite and Class III Malocclusion

In a Class III relationship, the lower teeth or jaw are positioned relatively further forwards than the upper teeth.

This can alter where the tongue and lips meet the teeth during articulation and has also been associated with differences in speech production.

However, the effects vary significantly between individuals, and speech alone is rarely enough to determine whether orthodontic treatment is required.

Crossbite

A crossbite occurs when one or more upper teeth bite inside the lower teeth rather than outside them.

Some studies have reported associations between crossbites and speech differences, possibly because altered dental arch relationships influence tongue posture. The evidence is less consistent than it is for anterior open bite.

Selected crossbites in growing children can sometimes benefit from early orthodontic treatment.

Severe Crowding

Crowding means there is insufficient space for the teeth to align normally.

Mild or moderate crowding often has little noticeable effect on speech because the tongue adapts. Very severe displacement of the front teeth may sometimes influence articulation, but crowding alone should not automatically be blamed for a speech difficulty.

Can Crooked Teeth Cause a Lisp?

They can contribute to some types of lisp, particularly when an open bite, abnormal front-tooth relationship or tongue-thrust pattern alters the pathway of air during speech.

The /s/ and /z/ sounds are particularly sensitive because they require a narrow and accurately directed stream of air.

However, many people who lisp have normally aligned teeth, and many people with open bites or crooked teeth do not lisp.

A lisp can therefore involve several interacting factors, including:

• Tongue placement
• Learned speech patterns
• Dental and jaw relationships
• Orofacial muscle function
• Hearing and speech development
• Structural differences elsewhere in the mouth

If a persistent lisp is the main concern, assessment by a speech and language therapist may be appropriate even when orthodontic treatment is also being considered.

Can Gaps Between Teeth Affect Speech?

A large gap between the front teeth can sometimes alter airflow during speech, particularly during sounds requiring controlled airflow near the incisors.

Small spaces commonly have no effect because the tongue quickly compensates.

If spacing is also an aesthetic or orthodontic concern, treatment options may include Invisalign or fixed orthodontic appliances depending on the cause and size of the spaces.

Can Missing Front Teeth Affect Speech?

Yes, temporary changes in articulation can occur when front teeth are missing because the tongue and airflow have to adapt to a different oral environment.

This is particularly noticeable with sounds formed close to the incisors.

Children naturally lose their front baby teeth during development and usually adapt well, so a temporary change in speech during this stage does not necessarily indicate a problem requiring dental treatment.

Can Tongue Thrust Cause Crooked Teeth and Speech Problems?

The relationship between tongue posture, swallowing, tooth position and speech is complicated because influence can occur in more than one direction.

Some children with anterior open bite also have:

• Forward tongue posture
• Tongue interposition during swallowing
• Persistent thumb or digit sucking
• Open-mouth posture
• Orofacial muscle-function differences

It may therefore be misleading to say simply that the tongue caused the bite problem or that the bite caused the abnormal tongue movement.

A 2025 review concluded that speech sound disorders and malocclusion have a multifactorial relationship and that multidisciplinary management may be useful where both structural and functional problems exist.

Can Thumb Sucking Affect Speech?

Persistent thumb or finger sucking can influence the developing teeth and bite, particularly when the habit continues for a prolonged period.

Possible dental effects include an anterior open bite and changes in upper dental-arch shape. Because open bite itself is associated with some speech sound differences, prolonged sucking habits may indirectly contribute to articulation difficulties in some children.

Glow Dental’s early orthodontic service includes assessment and management of persistent sucking habits where they are affecting dental development.

Can Orthodontic Treatment Improve Speech?

It can in selected patients, but improvement should not be guaranteed.

If a genuine structural problem—such as a significant anterior open bite—is interfering with the tongue position or airflow required for speech, correcting the malocclusion may remove one of the physical barriers to normal articulation.

However, a speech pattern that has developed over many years may not automatically change simply because the teeth have moved.

A person may continue using the same learned tongue placement after orthodontic treatment and may therefore benefit from speech therapy as well.

This is why orthodontics should not be advertised as a universal treatment for speech disorders.

Does Research Prove That Braces Improve Speech?

Current evidence shows a clearer association between certain malocclusions and articulation problems than it does between orthodontic treatment and guaranteed speech improvement.

A systematic review of children found a relationship particularly between anterior open bite and articulation distortions, but also concluded that more high-quality research is needed.

The most recent 2025 review reached a similar conclusion: malocclusion and speech sound disorders frequently occur together, but the exact causal relationship remains uncertain.

Orthodontic treatment should therefore be recommended for an identifiable orthodontic problem rather than solely on the assumption that braces will cure a speech disorder.

Can Invisalign Improve Speech Problems Caused by Crooked Teeth?

Invisalign can correct many types of crowding, spacing and bite problems, so it may potentially remove a structural factor that contributes to articulation in an appropriate case.

Whether Invisalign or fixed braces are preferable depends on the tooth movements required rather than the speech problem itself.

It is also worth knowing that Invisalign can temporarily affect speech when treatment begins.

A systematic review found that clear aligners can temporarily affect sounds including /s/, /z/, “sh”, “ch” and “th”. Most patients adapted within approximately one or two weeks, although adaptation occasionally took longer.

This temporary adjustment is very different from a longstanding speech sound disorder.

You can learn more about treatment and digital planning on our Invisalign page or view Invisalign before-and-after cases.

Can Fixed Braces Affect Speech Temporarily?

Yes, orthodontic appliances themselves can temporarily change speech while the tongue adapts to a new object in the mouth.

The effect varies considerably according to the appliance.

Conventional brackets on the front of the teeth generally have relatively little long-term impact on speech. Appliances placed on the inside of the teeth, palatal expanders and some removable retainers can have a more noticeable temporary effect because they occupy space normally used by the tongue.

Research shows that the sounds most commonly affected by orthodontic appliances include /s/, /z/, /t/, /d/ and other sounds requiring precise tongue positioning.

For most people, speech improves as the tongue adapts.

Do Retainers Affect Speech?

Some removable retainers can temporarily alter articulation when first fitted, particularly if they cover part of the palate.

Clear vacuum-formed retainers tend to occupy less palatal space but can still produce a short adaptation period.

This is not a reason to stop wearing a retainer. Retention is an essential part of maintaining orthodontic results, and speech usually adapts with regular wear.

When Should a Child With Speech Problems See an Orthodontist?

A child does not need orthodontic treatment simply because they pronounce a particular sound differently.

An orthodontic assessment becomes more relevant when speech difficulty occurs alongside a visible dental or bite problem such as:

• Anterior open bite
• Very prominent upper front teeth
• Significant underbite
• Crossbite
• Severe crowding or displaced teeth
• Persistent thumb or finger sucking
• Abnormal eruption of permanent teeth

Glow Dental provides children’s dentistry alongside early orthodontic assessment, allowing developing teeth and bite relationships to be monitored as a child grows.

When Should a Child See a Speech and Language Therapist?

A speech and language therapist assesses how speech sounds are produced and whether a difficulty is related to articulation, language development, motor control, hearing or other factors.

Speech and language assessment may be particularly useful when:

• The speech difficulty persists despite normal dental development
• The child is difficult for other people to understand
• Several speech sounds are affected
• A lisp persists beyond the expected developmental stage
• The speech difficulty remains after orthodontic correction
• There are concerns about language, hearing or swallowing as well as pronunciation

Where both malocclusion and a genuine speech sound disorder are present, orthodontic and speech-language care can address different aspects of the problem.

Should Orthodontic Treatment Be Started Early to Prevent Speech Problems?

Not routinely. The presence of a speech difference alone is not enough to justify early orthodontic treatment.

Children’s mouths and speech develop considerably as baby teeth are replaced by permanent teeth, and some bite problems also change naturally during growth.

Early treatment is most useful where there is a specific orthodontic indication—for example, certain crossbites, very prominent incisors, developing Class III relationships, problematic oral habits or abnormal eruption patterns.

An early orthodontic assessment can determine whether intervention now offers an advantage or whether monitoring until a later stage is more appropriate.

Can Adults Improve Speech by Straightening Their Teeth?

Potentially, but again it depends on whether tooth or jaw position is genuinely contributing to the speech difficulty.

An adult who has spoken normally for years despite crowded teeth is unlikely to develop dramatically clearer speech simply because those teeth are straightened.

An adult with a substantial open bite or another structural discrepancy affecting articulation may potentially notice a change after correction, but existing speech habits may still require adaptation or speech therapy.

Adults considering treatment can have their bite and tooth position assessed through Glow Dental’s specialist orthodontic service.

Can Jaw Surgery Improve Speech?

Very severe skeletal jaw discrepancies sometimes require a combination of orthodontics and orthognathic jaw surgery rather than tooth movement alone.

Changing jaw relationships can alter the structure of the oral cavity and therefore potentially affect articulation, but speech outcomes vary and cannot be guaranteed.

Patients with severe skeletal discrepancies require multidisciplinary specialist assessment rather than undergoing treatment primarily on the assumption that surgery will improve speech.

How Is a Speech-Related Orthodontic Problem Assessed?

An orthodontist may assess:

• The relationship between the upper and lower teeth
• Overjet and overbite
• Whether an open bite or crossbite is present
• Tooth crowding and spacing
• Jaw relationships and facial growth
• Tongue posture and oral habits where relevant
• The position and eruption of permanent teeth

Photographs, X-rays and digital scans may be used when clinically indicated.

Glow Dental uses digital scanning and orthodontic planning technology as part of its specialist orthodontic care.

Frequently Asked Questions About Crooked Teeth and Speech

Do crooked teeth cause speech problems?

They can contribute in some cases, but mild crookedness often has no noticeable effect. Certain bite problems, particularly anterior open bite, have a stronger association with articulation differences than simple crowding.

What speech sounds are most affected by crooked teeth?

Sounds requiring precise contact or airflow around the front teeth are most likely to be affected. Research frequently identifies /s/, /z/, /t/, /d/, /f/, /l/ and related sounds, but the pattern varies according to the malocclusion and the language being spoken.

Can an overbite cause a lisp?

A substantial overjet or other abnormal front-tooth relationship can contribute to altered articulation in some people, but it is not correct to assume every lisp is caused by an overbite.

Can an open bite cause a lisp?

Yes, anterior open bite is one of the dental relationships most consistently associated with distorted sibilant sounds and forward tongue placement during speech.

Can braces get rid of a lisp?

Possibly, if the lisp is partly caused by a structural dental problem that braces successfully correct. Orthodontics cannot guarantee that an established speech pattern will disappear, and speech therapy may also be required.

Will Invisalign affect my speech?

It can temporarily. Some patients notice a slight lisp or changes in particular sounds when they first start wearing clear aligners. Most adapt relatively quickly as the tongue becomes accustomed to the appliance.

Does crowding cause speech problems?

Severe crowding may contribute to articulation in some individuals, but mild crowding frequently has no effect because the tongue and lips adapt.

Can straight teeth improve pronunciation?

They may improve articulation where abnormal tooth position was genuinely interfering with tongue placement or airflow. Straightening teeth purely for cosmetic reasons should not be expected to change otherwise normal speech.

Should I see a dentist or a speech therapist first?

If there is an obvious bite or tooth-position concern, a dentist or orthodontist can assess the dental structure. If the main concern is pronunciation or speech development, a speech and language therapist may also be appropriate. Some patients benefit from assessment by both.

Orthodontic Assessment at Glow Dental

If you are concerned that tooth or jaw position may be affecting speech, Glow Dental provides specialist orthodontic treatment in Battersea for children and adults.

Our specialist orthodontic team can assess whether there is a structural bite problem such as open bite, crossbite, significant overjet or another malocclusion and explain whether orthodontic treatment is likely to provide a meaningful benefit.

Children with developing bite problems can be assessed through our early orthodontic service and children’s dentistry.

For adults and teenagers seeking a more discreet treatment option, Glow Dental also provides Invisalign clear aligners alongside fixed orthodontic treatments.

If you have not had your teeth and gums checked recently, a dental examination can also ensure they are healthy before orthodontic treatment begins.

New patients can view our current orthodontic fees or contact Glow Dental to arrange an assessment.

Conclusion: Do Crooked Teeth Affect Speech?

Certain forms of crooked teeth and malocclusion can influence speech, but the relationship is not simple. Anterior open bite has the strongest and most consistent association with articulation differences, while Class II, Class III and some crossbites may also affect how particular sounds are produced.

Mild crookedness often causes no speech problem at all because the tongue and lips adapt. Speech disorders can also arise for many reasons unrelated to the teeth.

Orthodontic treatment may improve speech where tooth or jaw position is a genuine contributing factor, but it should not be promised as a cure for a lisp or other speech sound disorder. Where appropriate, the best approach may involve both a specialist orthodontist and a speech and language therapist.