What is Thumb Sucking?
Thumb sucking is a habit often found in young children as a way to comfort themselves. Similar comforting behaviors might include the use of pacifiers, or sucking on fingers or blankets. Some see these behaviors, known as non-nutritive sucking behaviors, as a natural way for a child to sooth or stimulate themselves.
It’s common for kids to engage in these habits, usually stopping as they get older. Most of the time, thumb sucking tends to stop on its own between the ages of 2 and 4.
However, if thumb-sucking continues, it might lead to negative effects such as nail deformities or infections of the skin around the nail. Also, if the child still has this habit when their permanent teeth are coming in, it can cause the teeth to be misaligned. If thumb-sucking becomes an issue, there are several ways to deal with it. This can range from giving advice to the child and parents, fitting a dental appliance to discourage sucking, or using behavior modification techniques. The latter can include positive reinforcement, a reward calendar, or counseling among other methods.
Doctors need to understand these non-nutritive sucking habits, including thumb-sucking, as they can negatively impact oral health and have potential complications. If these habits continue past the age of 4 despite appropriate behavioural interventions, it may be necessary to refer the child to a pediatric dentist for evaluation.
What Causes Thumb Sucking?
The act of sucking is a natural reaction in babies that develops early on. It’s a way for children to comfort themselves and feel safe. To help soothe upset infants, caregivers often give them pacifiers.
A study conducted in Italy suggested that the habit of thumb sucking could be a way for kids to stimulate certain parts of their mouth and achieve a balanced muscle feeling, helping them to relax both mentally and physically. This suggests that thumb sucking might play a role in a child’s emotional development.
It’s worth noting that most children typically outgrow this behavior around the age of 4, as they start to develop better self-control skills.
Risk Factors and Frequency for Thumb Sucking
Thumb sucking and finger sucking, known as non-nutritive sucking habits, are common activities among children globally, across all socioeconomic groups. The prevalence of these habits can vary based on the child’s location. For instance, an 82% occurrence was found in children under five months old in Sweden, while in the U.S., 73% of the children between 2 and 5 years old showed these habits.
As kids get older, they usually discontinue these behaviors. Studies reflect these observations, showing that approximately half of the four-year-old children have sucking habits. This drops to about 12% in kids older than seven and less than 2% in twelve-year-olds.
- Non-nutritive sucking habits are common worldwide in children of all backgrounds.
- The prevalence of these habits can vary depending on the geographical area.
- For example, an 82% incidence rate was reported in Sweden for infants under five months, whereas in the U.S., 73% of children between 2 to 5 years old exhibited these behaviors.
- As children grow older, this habit generally decreases.
- About half of four-year-olds engage in this behavior which reduces to 12% in kids older than seven, and less than 2% in twelve-year-olds.
Signs and Symptoms of Thumb Sucking
When a child is frequently sucking their thumb, it’s important to understand how often this occurs, for how long, and with how much intensity. Most people who suck their thumbs might have blisters on the thumb they suck due to the vigorous sucking activity. You could also notice sucking pads or calluses, which are areas of thickened skin on the thumb. Inside the mouth, their upper teeth might lean outward, while their lower teeth lean inward – a result of the thumb’s position behind the upper teeth when sucking. The constant presence of the thumb could also interfere with the normal growth and alignment of the upper and lower teeth, leading to an open bite and an increased overjet, where the upper teeth excessively overlap the lower teeth.
- Frequency of thumb sucking
- Duration of thumb sucking
- Intensity of thumb sucking
- Blisters on the affected thumb
- Sucking pads or calluses on the thumb
- Upper teeth leaning outward
- Lower teeth leaning inward
- Interference with normal teeth growth and alignment
Testing for Thumb Sucking
A mouth check-up is important to look for any issues that may have been caused by thumb sucking. All children should have their first mouth check-up when their first tooth comes in, which is usually before they turn 1 year old. During this check-up, the doctor will look at the soft tissues of their mouth, the roof of their mouth (palate), the bony ridges that hold the teeth in place (alveolar ridges), and any teeth that have come in or are about to come in.
Once a child starts going to the dentist, their developing teeth and their bite (occlusion) should be checked regularly during their appointments. This helps the dentist keep an eye on any potential problems caused by thumb sucking.
Treatment Options for Thumb Sucking
There are several ways we can try to help a child stop thumb sucking. These can vary from talking with the child and their parents to understand the behavior better, to using different devices in the mouth. We might also try using different ways to change behavior like rewards or penalties, or even putting a bad tasting substance on the thumb. These methods can be used individually or together depending on the situation.
One particular research review conducted in 2015 found that using a dental brace or using behavior change techniques, or both, was more likely to help stop the thumb sucking when compared to no treatment.
There are several types of orthodontic devices we can use, including palatal cribs, spurs, palatal bars, hay rakes, and cage-type appliances. In severe cases, there might even be a need for surgery to adjust the jaw. However, after therapy it’s possible that the child could start thumb sucking again which could impact the teeth alignment.
There are also non-surgical treatments for children who have problems with teeth alignment caused by thumb sucking, including orofacial myofunctional therapy and stomahesive wafers. Orofacial myofunctional therapy is a set of exercises that help to retrain muscles used in swallowing and speaking. A study used stomahesive wafers, which are placed on the roof of the mouth, to help guide the tongue to rest in the right place.
With advances in technology, new methods have also been proposed. For example, one case study used a device that sounded an alarm when a child put their thumb in their mouth. The alarm was on a wristwatch which made it appealing for the child to wear. After monitoring the child for 15 months, it was found that the thumb sucking had significantly reduced and stopped altogether in 5 months. The child was then asked to wear the device for another 6 months to help avoid going back to thumb sucking.
What else can Thumb Sucking be?
Thumb sucking is simply a habit where a child sucks on their thumb. It doesn’t have any alternative medical explanations or conditions that mimic it.
What to expect with Thumb Sucking
Most children naturally stop thumb sucking between the ages of 2 and 4. Generally, this habit doesn’t cause any long-term issues. If a child’s teeth alignment (known as dental malocclusion) is affected due to thumb sucking, it will likely correct itself once the child stops the habit, particularly if any skeletal deformities are mild.
However, if a child continues to suck their thumb beyond the age of four, it may be necessary to start intervention strategies. It’s important to remember that even after successful treatment, there’s always a chance that a child might start thumb sucking again.
Possible Complications When Diagnosed with Thumb Sucking
Thumb sucking or similar non-nutritive sucking habits can lead to problems with the alignment of your teeth, specifically, an anterior open bite. When a child often suck their fingers, especially on one side, it can cause an uneven anterior open bite. The longer and more often the habit occurs, the worse the effect on the teeth.
The way thumb sucking can affect teeth alignment is due to the thumb’s presence inside the mouth. The thumb exerts pressure, especially on the teeth, which disrupts the natural eruption path of new teeth. According to a study by Lopez Freire and colleagues, children who have a history of finger sucking are 4.25 times more likely to have misaligned teeth compared to those who don’t have such history.
Severe misalignment of teeth or malocclusion is also positively linked to thumb sucking for long durations. Beyond affecting the teeth, the thumb itself can also have complications. These issues include deformities that may sometimes require surgery to correct.
Negative impacts of thumb sucking:
- Trouble with oral functionality development
- Potential speech disorders
However, the relationship between thumb sucking and speech disorders is unclear due to limited research. For example, a study by Baker and colleagues reported that there seemed to be no link between thumb sucking and the severity of speech impairment among 15% of Australian preschoolers who engaged in the habit. On the other hand, a study by Barbosa et al. reported that 18.3% of 128 participants with speech disorders had a history of finger sucking.
Preventing Thumb Sucking
It is important that parents and caregivers learn to use positive reinforcement with their children, such as commending them when they are able to avoid sucking their thumb. This can encourage children to stop the habit. Parents can also explore alternative methods to calm and comfort their children, as these can be effective strategies to distract them from thumb sucking. Regular reminders about not sucking the thumb can also be helpful. Additionally, involving older siblings or other family members in supporting the child to quit thumb sucking can make the process easier and more effective.
