An overbite caused by thumbsucking is a specific type of dental misalignment where the upper front teeth extend too far over the lower front teeth. This condition often occurs alongside an anterior open bite where the upper and lower teeth fail to meet when the mouth is closed. While thumb-sucking is a common, self-soothing habit in early childhood, its persistence creates significant pressure that reshapes the developing structures of the mouth. The resulting misalignment can affect a child’s ability to chew, their speech development, and their overall dental health. Addressing this issue requires stopping the underlying habit and correcting the dental and skeletal changes that have occurred.
How Thumbsucking Changes Jaw and Tooth Alignment
The continuous presence of the thumb inside the mouth acts as a physical barrier and a source of chronic force against the developing teeth and jawbones. The severity of the resulting malocclusion is directly correlated with the frequency, intensity, and duration of the sucking habit. Children who suck vigorously or for many hours a day, including while sleeping, are at the highest risk for developing dental complications.
The pressure exerted by the thumb pushes the upper front teeth forward, a movement called proclination, which increases the horizontal distance between the upper and lower incisors, or the overjet. Simultaneously, the lower front teeth are often pushed backward into a retroclined position. This combination of forces can prevent the front teeth from erupting fully, leading to the formation of an open bite where a gap remains between the biting surfaces of the upper and lower teeth.
The mechanical stress is not limited to the teeth; it also influences the growth and shape of the jawbones themselves. The constant force against the roof of the mouth, or the palate, can lead to a narrowing of the upper arch. This narrowing may cause a posterior crossbite, where the upper back teeth fit inside the lower back teeth. These combined dental and skeletal changes form the characteristic pattern of an overbite.
Strategies for Stopping the Habit
The most effective way to prevent permanent dental damage is to successfully stop the thumb-sucking habit before the permanent teeth begin to erupt, typically around age five or six. If the habit is discontinued before this time, the body’s natural growth processes often allow the teeth and jaw structures to self-correct, particularly in the case of a mild malocclusion. However, intervention is usually recommended if the behavior is intense or continues past the age of four.
Behavioral modification is the initial approach, focusing on positive reinforcement rather than punishment or shaming. Parents should praise the child for moments when they are not sucking their thumb, instead of reprimanding them when they are. Since the habit is often a source of comfort for anxiety or fatigue, addressing the root cause by offering alternative soothing methods is helpful.
If behavioral strategies are not successful, physical reminders can be employed to interrupt the habit’s sensory satisfaction. Over-the-counter agents with a bitter taste, which are painted onto the thumbnail, serve as an immediate, unpleasant deterrent. Protective gloves or specialized thumb-guards worn at night or during vulnerable times can also serve as a non-punitive physical barrier.
In cases where the habit persists despite these efforts, a pediatric dentist or orthodontist may recommend a fixed habit-breaking appliance. These small devices, such as a palatal crib or fence, are cemented behind the upper front teeth onto the molars. The appliance blocks the thumb from touching the sensitive palate, disrupting the pleasurable sensation the child seeks and effectively breaking the habit cycle.
Professional Treatments for Existing Overbites
Once the thumb-sucking habit has been completely stopped, professional orthodontic treatment can begin to correct the dental and skeletal changes that have occurred. The treatment plan is personalized based on the child’s age, the severity of the misalignment, and whether the issue is primarily dental or involves the jawbones. Dentofacial orthopedics, a specialized field, focuses on guiding the growth of the facial bones in a young, still-growing patient.
For children between the ages of six and ten, an orthodontist may recommend interceptive orthodontics, often called Phase I treatment. This early intervention is used to correct significant skeletal discrepancies, such as a narrow upper jaw or a jaw growth pattern that contributes to the overbite. Appliances like a palatal expander can widen the upper arch, creating the necessary space for the upper and lower jaws to align properly.
Dental correction for the protruding teeth is typically achieved using limited braces or removable retainers that incorporate specific springs or wires. These appliances apply gentle, continuous forces to move the upper incisors back into their correct position and close any remaining open bite. This phase aims to create a healthier environment for the permanent teeth to erupt and may simplify or shorten the second phase of treatment.
Comprehensive orthodontics, or Phase II treatment, usually takes place once most or all of the permanent teeth have erupted, typically around age 12 or 13. Full braces or clear aligners are used to make precise movements to the teeth and finalize the bite correction. Following active treatment, a retainer must be worn consistently to ensure the teeth remain in their corrected positions and prevent relapse.