An overjet describes the horizontal projection of the upper front teeth beyond the lower front teeth. While a small degree of overjet is normal, an increased overjet may affect bite balance, increase the risk of trauma to the front teeth, and influence facial profile.
The term overjet refers to the horizontal distance between the edges of the upper and lower front teeth when the mouth is closed. Sometimes informally called "buck teeth," an increased overjet means the upper front teeth sit noticeably further forward than the lower front teeth.
A mild overjet is a normal feature of dental alignment. However, when the horizontal projection becomes excessive, it may have functional implications — including an increased vulnerability of the front teeth to injury, difficulty closing the lips comfortably, and in some cases, effects on bite balance and jaw comfort.
A professional dental assessment can determine the severity of an overjet and identify whether the underlying cause is related to tooth positioning, jaw size, or a combination of both. This page explains what an overjet involves, why it develops, and the orthodontic options that may be available.
An overjet measures the horizontal distance between the front edge of the upper incisors and the front edge of the lower incisors. It is assessed with the teeth in their normal biting position and is measured in millimetres.
A normal overjet is generally considered to be between 2 and 4 millimetres. When the measurement exceeds this range, it is described as an increased overjet. The greater the projection, the more pronounced the functional and aesthetic effects may be.
It is important to distinguish between overjet and overbite, as the two terms are often confused. An overjet describes the horizontal relationship — how far forward the upper teeth sit relative to the lower teeth. An overbite, by contrast, describes the vertical overlap — how much the upper front teeth cover the lower front teeth from top to bottom. Both measurements are assessed independently, and it is possible to have an increased overjet, an increased overbite, or both.
An overjet may be classified as dental — where the issue relates primarily to the angle or position of the teeth — or skeletal — where the underlying jaw relationship is the main contributing factor. In many individuals, a combination of dental and skeletal components is present.
An increased overjet can develop for a variety of reasons. The underlying cause often differs from person to person, and in many cases a combination of dental and skeletal factors may be involved:
Inherited traits play a significant role in determining the size and position of the upper and lower jaws. If the upper jaw is naturally positioned further forward relative to the lower jaw, or if the lower jaw is set further back, the resulting skeletal relationship may contribute to an increased overjet.
Differences in the growth rate or final size of the upper and lower jaws can create a mismatch. A relatively prominent upper jaw (maxillary protrusion) or a smaller, retruded lower jaw (mandibular retrusion) — or a combination of both — may result in the upper front teeth sitting well ahead of the lower teeth.
Persistent thumb sucking or extended use of a dummy during childhood can exert forward pressure on the upper front teeth while restricting the forward development of the lower jaw. These forces, sustained over time, may contribute to increased projection of the upper incisors.
A tongue thrust swallowing pattern — where the tongue pushes against the back of the upper front teeth during swallowing — can gradually move the upper incisors forward. This habitual pressure may maintain or worsen an existing overjet over time.
Losing baby teeth earlier than expected can disrupt the natural guidance that primary teeth provide for the eruption of permanent teeth. Without this guidance, permanent teeth may erupt in unfavourable positions, potentially contributing to an increased overjet.
The upper and lower jaws do not always grow at the same rate or to the same degree. Individual variations in jaw development — particularly during adolescence — can influence the final relationship between the upper and lower teeth and the resulting overjet.
A professional assessment can help identify the contributing factors in your individual case and inform any recommendations for management.
Not all individuals with an increased overjet experience noticeable symptoms. However, as the degree of projection increases, the following effects may become more apparent:
Upper front teeth that project significantly beyond the lower teeth are more exposed and vulnerable to injury. This is particularly relevant during sports, falls, or accidental impacts, where protruding teeth may be more likely to sustain fracture or damage.
When the overjet is pronounced, it may be difficult to close the lips comfortably over the front teeth at rest. This lip incompetence can result in the upper teeth being visible even when the mouth is relaxed, and may contribute to dryness of the front teeth and gum tissue.
In some cases, a significant overjet may influence the production of certain speech sounds, particularly those that require contact between the tongue and the back of the upper teeth. The degree of impact varies and is not present in all individuals with an increased overjet.
Certain bite relationships associated with an increased overjet may place additional strain on the jaw joint and surrounding muscles. This may contribute to discomfort, fatigue, or tension in the jaw area, particularly during chewing.
Some individuals may feel self-conscious about the prominence of their upper front teeth or the resulting facial profile. While overjet is primarily a functional dental consideration, the visual aspect may also be a factor in seeking assessment.
If you are experiencing any of these effects, a dental assessment can help determine whether they are related to an increased overjet and what management options may be available.
An increased overjet may place strain on the front teeth and their supporting structures, particularly if the teeth are exposed and vulnerable to impact. A dental assessment provides a clear understanding of the extent and nature of the overjet.
During an assessment, digital scans or imaging may be used when clinically indicated to evaluate the relationship between the upper and lower jaws. This information helps determine whether the overjet is primarily dental, skeletal, or a combination of both — which in turn influences the treatment approach.
The severity of the overjet is an important factor in orthodontic planning. Mild cases may require minimal intervention, while more significant projections may benefit from a structured treatment plan. Early assessment in children may also be valuable, as it allows the dentist to monitor jaw growth and determine the most appropriate time for intervention.
Adult cases can also be managed successfully. While jaw growth is no longer a factor, orthodontic tooth movement can still help reduce an increased overjet and improve bite balance in many situations.
The most suitable approach to managing an increased overjet depends on the patient's age, the severity of the projection, whether the cause is dental or skeletal, and overall oral health. Treatment aims to reduce excessive projection and may help improve bite balance. Options may include:
Traditional fixed braces use brackets and wires to gradually reposition the teeth and improve the bite relationship. This approach can address a range of overjet severities and allows precise control over tooth movement in both the upper and lower arches.
For suitable cases, clear removable aligners may be used to reduce an increased overjet with a more discreet treatment approach. Aligners work by applying controlled forces to move the teeth incrementally towards a more balanced position.
In younger patients whose jaws are still developing, functional appliances may be used to encourage forward growth of the lower jaw relative to the upper jaw. This approach takes advantage of natural growth patterns and is typically used during adolescence.
After active orthodontic treatment, retainers are typically recommended to maintain the corrected tooth positions and prevent the overjet from relapsing. Both fixed and removable retainer options may be discussed as part of the treatment plan.
Treatment suitability depends on individual assessment. Your dentist or orthodontist will discuss which approach may be most appropriate for your situation and explain what each option involves in terms of the treatment process.
The approach to managing an increased overjet may differ depending on the age of the patient, as the treatment options available are influenced by whether the jaws are still growing.
Growth monitoring may be recommended to assess how the jaws are developing relative to one another
Early orthodontic input can help guide jaw development and may reduce the complexity of later treatment
Not all children with an increased overjet require immediate treatment — some cases are monitored until the optimal time for intervention
Orthodontic treatment for an increased overjet is common and can be effective in adults
Treatment planning considers bone support, gum health, existing restorations, and individual anatomy
Results depend on individual factors, and a realistic discussion of expectations forms an important part of the planning process
Whether the patient is a child or an adult, the starting point is always a thorough clinical assessment to understand the nature and severity of the overjet and to determine the most appropriate management approach.
If you notice prominent upper front teeth, increased horizontal projection, or concerns about bite balance, a dental assessment can determine whether orthodontic treatment may be appropriate. Our dental team can evaluate your bite and discuss the options that may be suitable for your needs.
Orthodontic assessment and overjet treatment are available at our London clinics. You can attend our South Kensington dental clinic or our St Paul's Dental Clinic for a professional dental evaluation.
South Kensington Medical & Dental is registered with the Care Quality Commission (CQC) and our clinicians are registered with the relevant UK regulatory bodies, including the GDC and GMC. Our dentists, dental nurses and medical professionals deliver care that meets the highest clinical, safety and ethical standards, because our patients deserve nothing less.
