Consequences of thumb-sucking
Thumb-sucking is a natural behaviour in babies and young children and forms part of the oral stage of child development. However, when the habit persists, it can lead to dental and emotional problems that you should be aware of. In this article, we explain why it happens, when to take action and what resources are available to you.
Key conclusions
- Thumb-sucking is normal in early childhood, and most children stop doing it of their own accord between the ages of 2 and 4.
- If it persists severely for more than 3–4 years, it can cause deformity of the upper jaw, lead to malocclusions and require interceptive orthodontic treatment.
- Any intervention should always be respectful and gradual: punishment increases stress and reinforces the behaviour rather than eliminating it.
- At Clínicas Udemax (Palma de Mallorca), we can assess the effects of thumb-sucking and plan the most appropriate treatment from the very first free consultation.
Why do children suck their thumbs?
Babies begin to suck their thumbs whilst still in the womb. In fact, ultrasound scans show this sucking reflex from the 15th–20th week of pregnancy, confirming that it is an innate behaviour rather than a learned one. Children use this habit to explore themselves and their surroundings, and it is key to sensory development during childhood.
What is its purpose? Sucking releases endorphins and creates a sense of relief, which aids emotional self-regulation and promotes calm. Thumb-sucking helps children to calm themselves emotionally and reduce physical and emotional tension. Children often suck their thumbs to feel secure, find comfort and fall asleep.
It is common for many babies to alternate between thumb-sucking and using a dummy, depending on the moment and the situation. Thumb-sucking tends to occur mainly at bedtime, in response to changes such as starting nursery or the birth of a sibling, or simply when the child is tired. Thumb-sucking can act as a coping mechanism for stress at any stage of life.
How long is it normal to suck your thumb?
Thumb-sucking is common in early childhood, but there is a healthy limit to it. It is advisable to stop thumb-sucking before the age of 3, and children may stop thumb-sucking spontaneously between the ages of 2 and 4. From a paediatric dentistry perspective, it is considered normal up to 24 months and requires monitoring up to 3–4 years of age if there are no signs of dental problems.
If thumb-sucking continues intensively on a daily basis after the age of 4–5, the risk of dental problems increases considerably. Key fact: 12.1 per cent of children over the age of 7 still suck their thumbs, and 1.9 per cent of 12-year-olds still do so. It is common for the habit to resurface during adolescence due to anxiety or stress.
Consequences of thumb-sucking beyond the recommended age
The consequences depend on the frequency, intensity and position of the finger in the mouth. The first signs may appear as early as 3–4 years of age if the habit is very pronounced. If action is not taken in time, some skeletal deformities may become difficult to correct and require longer and more complex orthodontic treatment.
Abnormalities in the growth of the upper jaw
Continuous pressure from the finger on the palate can narrow and deform the upper jaw, resulting in a narrow, high palate. A high-arched palate is a deformity caused by prolonged thumb-sucking. The upper teeth tend to ‘protrude’ (protrusion), creating discrepancies with the lower jaw that affect facial harmony. These abnormalities are one of the consequences of thumb-sucking that require early assessment.
Malocclusions and bite problems
Thumb-sucking can affect the alignment of the teeth and lead to dental malocclusions such as:
- Open bite: the upper and lower incisors do not touch when the mouth is closed.
- Posterior crossbite: the upper molars fit inside the lower ones.
- Protrusion of the incisors: the upper front teeth tilt outwards.
These malocclusions make chewing difficult and can lead to compensatory jaw movements. Many of them can be corrected with interceptive orthodontic treatment if diagnosed between the ages of 6 and 10.
Disorders affecting swallowing, speech and breathing
Prolonged use of a pacifier can lead to atypical swallowing, where the child pushes their tongue between their teeth when swallowing. This behaviour can affect the correct pronunciation of certain phonemes such as /s/, /z/, /t/ and /d/, leading to childhood dyslalia. A narrow upper jaw also restricts nasal breathing and is associated with mouth breathing, snoring and less restful sleep. Oropharyngeal infections may result from thumb-sucking due to constant contact between the hands and the mouth, which affects oral hygiene. In some cases, a combination of orthodontic treatment and speech and language therapy is the most appropriate course of action.
Associated emotional and social problems
The habit does not just have a physical impact. From the age of 5–6, some children feel embarrassed if their classmates point out that they still suck their thumb. This can affect their self-esteem and cause further anxiety, which, paradoxically, reinforces the behaviour. A respectful approach from both the family and the professional helps to break this cycle.
When should I be concerned and see a dentist?
There is no need to be alarmed during the first few months of the habit. However, dental check-ups are recommended if the habit persists beyond the age of 3–4 years. Specific warning signs:
- Front teeth that protrude significantly or are widely spaced
- Visible open bite
- Difficulty closing the lips at rest
- Narrow or very high palate
- Speech problems or habitual mouth breathing
The first tooth should erupt before the child is one year old, and from that point onwards it is advisable to make an appointment with the dentist. At Udemax Clinics, we recommend a first visit before the age of 3 or as soon as a very intense thumb-sucking habit is detected.
How to help your child stop sucking their thumb
The aim is for the child to want to stop thumb-sucking of their own accord, not to comply because of external pressure. The key is to identify the times when they do it most and to address those situations. Here are some specific strategies.
Strategies at home: positive reinforcement and clear boundaries
- Talk to your child in simple terms about the effects of this habit on their ‘permanent teeth’.
- Use calendars or sticker charts to reward moments when they aren’t sucking their thumb, especially at bedtime.
- It is recommended that you do not pressure or ridicule the child for this behaviour. Parents should avoid punishment, constant scolding or humiliation, as these increase anxiety.
- Agree on realistic goals and celebrate every achievement.
Alternatives to the habit of sucking
Many children need a different kind of stimulus to help them relax and feel calm. Replacing the thumb with a soft toy can help children, as can a soft blanket or a stress-relief toy. With very young children, it is sometimes helpful to curb the habit by temporarily replacing it with a dummy, which is then easier to wean them off. Establishing relaxing bedtime routines – such as reading a story, playing soft music or giving a massage – reduces the need for sucking as a form of comfort.
External resources: products and quick reminders
In some cases, plasters, silicone thimbles or bitter-tasting nail varnishes can be used as gentle reminders. These tools work best when the child is already showing motivation. Methods that cause pain, fear or embarrassment should not be used. If these measures are not sufficient, it is advisable to consult a professional to explore more specific solutions.
Interceptive orthodontics and treatments at Udemax Clinics
Interceptive orthodontics is the branch of dentistry that intervenes during growth to guide the development of the bones and teeth, thereby preventing future problems. At Udemax Clinics, we have over 40 years’ experience in Mallorca and a team specialising in paediatric dentistry who undergo continuous professional development. We recommend an initial assessment at around 6–7 years of age, or earlier if thumb-sucking is a particularly pronounced habit.
What does interceptive orthodontic treatment involve for this habit?
Fixed or removable intraoral appliances – such as a palatal splint – are used to prevent the finger from being placed comfortably behind the front teeth. These appliances do not cause pain, but they make sucking less pleasurable, making it easier for the child to give up the habit. Where the upper jaw is narrow, these devices may be combined with expanders to restore the correct shape of the palate. The process usually takes several months, and is tailored to the child’s age, the duration of the habit and the observed consequences.
Benefits of receiving treatment at Udemax Clinics (Palma de Mallorca)
- Three clinics in Palma, making it easier for families from different parts of Mallorca to access them.
- A free initial consultation to assess your habits and their potential effects.
- Book an appointment online or call the emergency helpline (607 833 629) if you have any queries regarding broken devices or other issues.
- Advanced technology and state-of-the-art materials to make treatments for children more comfortable and effective.
What if my child can’t stop sucking their thumb?
In some cases, the habit is deeply ingrained and can be more difficult to break. It is essential to stay calm, avoid placing blame, and continue to offer reassurance and alternatives to help the child feel comforted. At Udemax Clinics, the team can liaise with other professionals – paediatricians, child psychologists and speech and language therapists – if deemed necessary. With a personalised plan and regular check-ups, it is possible to minimise the effects of thumb-sucking and protect the child’s oral development throughout their growth.
Frequently asked questions about thumb-sucking
Is it better for my baby to use a dummy rather than suck their thumb?
From a dental point of view, a dummy is usually preferable because it can be weaned off gradually and in a controlled manner, whereas the thumb is always available. Ideally, the use of a dummy should be limited to bedtime and it should be phased out between 18 and 24 months. The decision should be tailored to the child’s temperament and discussed with the paediatrician and paediatric dentist.
Can thumb-sucking affect permanent teeth if it is stopped in time?
If treatment is carried out before the permanent teeth have fully erupted – at around 6 to 8 years of age – many problems can be corrected or minimised. Children’s bones and teeth are highly malleable, so well-planned interceptive orthodontic treatment can restore near-normal development. In contrast, severe, untreated problems can leave a lasting impact on the adult dentition.
How often should I take a child who sucks their thumb for a check-up?
It is advisable to have at least one check-up a year, and every six months if the habit is severe or the child is over 3–4 years old. The dentist monitors changes in the upper jaw, the bite and tooth eruption so that action can be taken in good time. At Udemax Clinics, we can draw up a schedule of appointments tailored to each individual case.
Is there a link between thumb-sucking and sleep problems?
Many children associate thumb-sucking with falling asleep and waking up during the night. When breaking this habit, it may take a few days for them to fall asleep more easily, so it is a good idea to introduce alternative relaxing routines. If the sleep problems are significant, it is advisable to discuss this with your paediatrician as well.
At what age can a child start wearing a device to stop thumb-sucking?
Intraoral appliances are usually recommended from the age of 5–6, when the child is cooperative and understands the purpose. For younger children, the focus is on behavioural management with the mother, father and family, positive reinforcement and, where appropriate, weaning off the dummy. The final decision is made following an individual assessment in the clinic, taking into account the child’s maturity, the findings of the clinical examination and their dental history. In this ongoing care, each practice and each child requires recommendations tailored to their specific health needs.
