Overjet (Buck Teeth): Causes and Treatment Options

What Is Overjet (Buck Teeth)?

Overjet is measured as the horizontal distance from the edge of the upper front teeth to the front surface of the lower front teeth. A normal overjet is typically between two and four millimetres. When this measurement exceeds four millimetres, the anterior projection becomes clinically significant and may benefit from correction. Severe cases can measure ten millimetres or more.

The severity of the condition varies widely. Mild overjet may be barely noticeable and cause no functional problems, while pronounced protrusion can significantly alter the facial profile, make lip closure difficult, and leave the front teeth exposed and vulnerable to accidental damage.

Early recognition is important because overjet often becomes more pronounced during the teenage growth spurt if left unmonitored. In children, interceptive treatment can take advantage of ongoing jaw development to guide teeth and bone into a more favourable relationship. In adults, treatment remains highly effective but relies on tooth movement rather than growth modification.

Beyond the physical aspects, prominent front teeth can have a notable impact on self-confidence. Many patients with significant overjet report feeling self-conscious about their smile, covering their mouth when laughing, or avoiding photographs. These social and emotional effects are a valid reason to explore correction options alongside the functional benefits.

Overjet vs Overbite: What's the Difference?

Overjet and overbite are frequently confused, but they describe two distinct measurements of how the upper and lower teeth relate to each other. Understanding the difference helps clarify your diagnosis and the treatment approach your dental team recommends.

It is common for both conditions to be present at the same time. A patient may have protruding upper teeth (overjet) that also cover a significant portion of the lower teeth (overbite). However, they require different treatment strategies. Overjet correction focuses on retracting the upper front teeth backward, while overbite correction focuses on intruding or adjusting the vertical position of the teeth. Your dental team will assess both measurements during your consultation.

What Causes Overjet (Buck Teeth)?

Overjet develops from a combination of inherited and environmental factors. Understanding the underlying cause is essential because it determines whether treatment targets the teeth alone, the jaw relationship, or both.

Genetic and Skeletal Factors

The most common cause of significant overjet is an inherited discrepancy in jaw size or position. When the upper jaw (maxilla) grows further forward than the lower jaw (mandible), or when the lower jaw is naturally set back, the upper teeth sit well ahead of the lower teeth. This skeletal pattern — classified as a Class II malocclusion — runs strongly in families. If one or both parents have protruding incisors or a receding chin profile, their children are more likely to develop a similar pattern.

Childhood Habits

Prolonged thumb sucking, dummy or pacifier use beyond age three to four, and persistent tongue thrusting can all push the upper front teeth forward over time. The sustained pressure of a thumb or dummy against the back of the upper incisors gradually tips them outward, increasing the horizontal overlap. The longer these habits continue, the more pronounced the effect becomes, and the more likely the changes are to become permanent without orthodontic intervention.

Dental Factors

Missing lower teeth can allow the upper teeth to drift forward into the unsupported space. Crowding in the upper arch may push individual teeth outward, creating localised protrusion. Retained baby teeth that do not shed on time can redirect emerging permanent teeth into an angled position. These dental factors can create or worsen overjet even when the underlying jaw relationship is normal.

Mouth Breathing

Chronic mouth breathing — often caused by nasal congestion, enlarged adenoids, or allergies — alters the resting position of the tongue and the balance of forces acting on the teeth. When the mouth is habitually open, the tongue drops away from the palate, and the outward pressure of the cheeks is no longer counterbalanced. Over time, this can narrow the upper arch and tip the front teeth forward, contributing to increased overjet.

Types of Overjet

Overjet is classified according to its underlying cause, which directly influences the treatment approach. Your dental team will identify which type is present during your assessment.

Dental Overjet

In dental overjet, the upper front teeth are angled forward but the underlying jaw relationship is normal. The maxilla and mandible are well-proportioned and correctly positioned relative to each other — the problem lies purely in the angulation of the incisor teeth themselves.

• Generally the most straightforward type to treat with orthodontics alone
• Braces or aligners can tip the teeth back to their correct angulation
• Often caused by childhood habits or localised crowding

Skeletal Overjet

Skeletal overjet results from a genuine discrepancy in jaw size or position. The upper jaw may be positioned further forward than normal (maxillary protrusion), or the lower jaw may be set further back (mandibular retrusion), or a combination of both. This creates a gap between the upper and lower teeth that reflects the underlying bone relationship.

• More complex to treat, particularly in adults whose jaw growth is complete
• In growing children, functional appliances can modify jaw growth patterns
• Severe adult cases may require orthognathic surgery combined with orthodontics

Combined Overjet

Many patients present with a combination of both dental and skeletal factors. The teeth may be angled forward on top of a jaw relationship that already places the upper teeth ahead of the lower. This combined presentation is common and requires a treatment plan that addresses both the tooth position and the underlying skeletal contribution for the most stable, long-lasting result.

Signs and Symptoms of Overjet

Overjet produces a range of visible, functional, and social effects. The following signs help you recognise whether you or your child may have a significant horizontal overlap that could benefit from assessment.

• Visible protrusion — the upper front teeth stick out prominently beyond the lower lip line, often visible even when the mouth is relaxed or partially open
• Difficulty biting — trouble biting cleanly through foods like sandwiches, apples, or pizza because the upper and lower front teeth do not meet properly
• Lip closure issues — difficulty closing the lips comfortably over protruding teeth, sometimes resulting in the lips appearing strained or the mouth resting slightly open
• Speech concerns — a lisp or difficulty producing certain sounds clearly, particularly “s,” “z,” and “th” sounds, due to the gap between the upper and lower teeth
• Increased risk of trauma — protruding front teeth are significantly more vulnerable to chipping, fracture, or being knocked out during falls, sports, or accidental impacts
• Self-consciousness — smiling with the mouth closed, hiding teeth with a hand, or avoiding social situations where the teeth are visible

Why Treat Overjet?

While mild overjet may not cause significant problems, moderate to severe cases can affect oral health, daily function, and long-term dental stability. Understanding the potential consequences helps you make an informed decision about whether treatment is right for you.

• Dental trauma — research consistently shows that protruding front teeth are significantly more likely to be chipped, fractured, or knocked out in falls and accidents, particularly in active children and those who play sports
• Speech difficulties — the gap between the upper and lower incisors can affect the tongue's ability to make proper contact for certain sounds, leading to pronunciation challenges
• Chewing problems — when front teeth do not meet, biting into food becomes inefficient, often forcing compensatory biting with the side teeth
• Jaw discomfort — the compensatory bite patterns that develop when front teeth do not function properly can place strain on the jaw joints and muscles
• Self-esteem concerns — visible protrusion can affect social confidence, willingness to smile, and comfort in professional or personal interactions
• Uneven tooth wear — abnormal contact patterns cause some teeth to bear more force than they should, leading to premature wear, chipping, or surface damage
• Gum problems — protruding teeth may cause the lower lip to press against the gum tissue behind the upper teeth, contributing to recession or chronic irritation over time

Diagnosis and Assessment

A thorough assessment is the foundation of effective overjet treatment. Your dental team will evaluate several aspects of your bite and facial profile to determine the type, severity, and most appropriate treatment approach.

• Clinical examination — a detailed visual assessment of the position and angulation of your front teeth, the relationship between your upper and lower jaws, and your overall facial profile
• Measurement — precisely quantifying the horizontal overlap in millimetres to classify the overjet as mild, moderate, or severe and track progress throughout treatment
• Bite analysis — evaluating how your teeth come together, identifying any associated conditions such as overbite, crossbite, or crowding, and assessing how they affect function
• Discussion of concerns — understanding your personal goals, the functional problems you experience, and any aesthetic concerns to ensure the treatment plan aligns with your priorities

Treatment Options for Overjet Correction

The right treatment depends on the severity of the overjet, the patient's age, and whether the cause is dental, skeletal, or a combination. In children who are still growing, early intervention can guide jaw development and simplify later treatment. In adults, treatment focuses on repositioning teeth within the existing jaw framework. Your dental team will recommend the approach most likely to achieve a stable, long-lasting result.

Orthodontic Treatment (Braces)

Traditional fixed braces remain one of the most effective methods for correcting overjet. Brackets bonded to the teeth are connected by archwires that apply controlled, continuous force to gradually retract the protruding upper incisors into proper alignment.

• Effective for all severities of overjet, from mild to severe
• Elastics (rubber bands) may be used to help correct the jaw relationship by connecting upper and lower braces
• Provides precise control over tooth movement in all three dimensions

Our orthodontic treatments include a range of fixed brace options suited to different needs and preferences.

Invisalign Clear Aligners

Invisible braces such as Invisalign use a series of custom-made, removable clear trays to gradually reposition the teeth. Each set of aligners is worn for one to two weeks before progressing to the next, with each tray making small, precise adjustments.

• Suitable for mild to moderate overjet correction in compliant patients
• Virtually invisible, making them popular with adults and professionals
• Removable for eating and cleaning, maintaining better oral hygiene during treatment
• Severe skeletal overjet or complex cases may require fixed braces for more predictable results

Tooth Extraction

In some cases, removing teeth — most commonly the upper first premolars — creates the space needed to retract the protruding front teeth backward into a more favourable position. Extractions are carried out as part of a planned orthodontic strategy and the resulting spaces are closed during brace treatment, leaving no visible gaps.

Orthopaedic Appliances (for Children)

In growing children with skeletal overjet, functional appliances can harness the body's natural growth potential to improve the jaw relationship. These removable or fixed devices encourage the lower jaw to grow forward and the upper jaw to restrain, reducing the skeletal discrepancy before the teenage growth spurt is complete. Early intervention with functional appliances can simplify or even eliminate the need for more complex treatment later.

Surgery (for Severe Skeletal Cases)

In adults with a significant skeletal discrepancy that cannot be adequately corrected with orthodontics alone, orthognathic (jaw) surgery may be recommended. This involves repositioning the upper jaw, the lower jaw, or both to create a balanced facial profile and a functional bite.

• Combined with orthodontics before and after surgery for the best result
• Reserved for cases where the skeletal component is too large for orthodontic camouflage
• Your dental team will discuss all available options before recommending a surgical path

Retainers for Stability

After active treatment, retention is essential to prevent the teeth from drifting back toward their original position. A fixed retainer — a thin wire bonded behind the front teeth — provides continuous, maintenance-free retention. Removable retainers may also be recommended for night-time wear. Consistent retainer use is the single most important factor in maintaining your results long term.

Overjet Before and After

Successful overjet correction produces meaningful improvements in both function and appearance. While every case is unique, patients can generally expect the following outcomes following completed treatment.

• Reduced horizontal protrusion — the upper front teeth sit in a more natural position relative to the lower teeth, within the ideal two to four millimetre range
• Improved lip closure — the lips close more comfortably and naturally without strain, improving the resting facial profile
• Better biting and chewing — the upper and lower front teeth meet properly, allowing efficient incising of food
• Enhanced smile aesthetics — teeth that sit in proper alignment create a more balanced, confident smile
• Reduced trauma risk — retracted teeth are significantly less exposed to accidental damage during activities and sport
• Improved confidence — patients consistently report feeling more comfortable smiling, speaking in public, and interacting socially after correction

See examples of how orthodontic treatment has transformed smiles for our patients in the smile gallery.

Buck Teeth in Children vs Adults

The approach to overjet correction differs significantly depending on whether the patient is still growing. Both age groups can achieve excellent results, but the treatment methods and timelines vary.

Treating Overjet in Children

• Growth modification — functional appliances can redirect jaw growth during the pre-teen and early teenage years, addressing the skeletal component of overjet while the body is still developing
• Habit intervention — identifying and stopping thumb sucking, tongue thrusting, or mouth breathing early prevents the overjet from worsening and may allow natural improvement
• Two-phase approach — an initial phase using functional appliances to improve the jaw relationship, followed by braces during the teenage years to align individual teeth
• Trauma prevention — reducing overjet during childhood significantly lowers the risk of front tooth injuries during play and sport

Treating Overjet in Adults

• Orthodontic camouflage — braces or aligners reposition the teeth to reduce the overjet, even when the underlying skeletal relationship cannot be changed without surgery
• Extraction-based retraction — removing premolars provides space to pull the protruding front teeth back, a well-established and highly effective approach in adult treatment
• Combined treatment — overjet correction in adults is often part of a broader treatment plan that may include addressing crowding, spacing, or bite issues at the same time
• Surgical option — significant skeletal discrepancies in adults may require jaw surgery in conjunction with braces for the most complete and stable correction

Can Overjet Be Prevented?

While genetic factors cannot be controlled, several practical measures can reduce the risk of overjet developing or worsening, particularly in children.

• Early orthodontic assessment — an initial dental examination around age seven allows your dental team to identify developing overjet and intervene at the optimal time
• Discouraging prolonged habits — gently weaning children from thumb sucking and dummy use by age three to four prevents the sustained pressure that pushes front teeth forward
• Addressing mouth breathing — if your child habitually breathes through the mouth rather than the nose, identifying and treating the cause (such as allergies or enlarged adenoids) can help protect normal jaw and tooth development
• Protecting teeth from trauma — wearing a mouthguard during contact sports and active play protects protruding teeth from damage while treatment is being planned or carried out

When to See a Dentist About Overjet

Whether you are an adult concerned about protruding teeth or a parent noticing early signs in your child, professional assessment is the first step toward understanding your options.

• Protruding front teeth are causing self-consciousness or affecting your confidence
• Difficulty biting or chewing food properly with the front teeth
• Speech concerns such as lisping or difficulty with certain sounds
• Concern about increased risk of dental trauma during sports or daily activities
• Jaw pain, discomfort, or fatigue from compensatory bite patterns
• The upper and lower teeth do not meet when biting together
• Your child is approaching age seven and you have noticed early signs of dental prominence

Our dental team at St Paul's Medical & Dental provides comprehensive orthodontic assessments and a full range of correction options for patients of all ages. Book a consultation to discuss your concerns and explore the treatment best suited to your needs. For details on our fees, visit our treatment fees page.

Frequently Asked Questions About Overjet