What Are Flared Teeth? Causes and Treatment Options

Flared teeth are teeth that tilt outward, away from the mouth, instead of sitting upright in the jaw. The condition most often involves the upper front teeth and is known clinically as proclination or protrusion. A normally positioned upper central incisor sits at roughly 109 to 110 degrees relative to the upper jaw plane; when that angle climbs toward 125 degrees or beyond, the tooth visibly fans forward and the lip may no longer rest comfortably over it.¹ Flaring can be something you are born with, something that develops gradually because of gum disease or habits, or even a side effect of earlier dental work. Because the causes differ so widely, the right treatment depends entirely on why the teeth moved in the first place.

What Flaring Actually Looks Like

The hallmark is upper incisors that project forward at a steeper angle than normal. You might notice the teeth look “buck” or fan-shaped when you smile, or that your lips can’t close without effort. Dentists measure the tilt using angles on a lateral head X-ray. One common reference is the angle between the long axis of the upper incisor and a skull landmark line (the SN plane), where normal falls roughly between 97 and 115 degrees.² Another measurement, the interincisal angle, captures how the upper and lower incisors meet: the more flared the teeth, the smaller that angle becomes, with a normal average sitting around 135 degrees.¹

Flaring is not always symmetrical. One incisor might tilt outward more than the other, or a lateral incisor might flare while the central ones stay relatively upright. Sometimes the lower front teeth are involved too, a condition called bimaxillary protrusion, where both upper and lower incisors angle forward. That pattern tends to produce a fuller, more prominent lip posture and is sometimes accompanied by an inability to close the lips at rest, a gummy smile, or chin-muscle strain.³

Gum Disease as a Major Driver

If your teeth gradually fanned outward in your thirties, forties, or later, periodontal disease is the most likely culprit. When the bone and ligament holding a tooth in place break down, the tooth loses its anchor and drifts under everyday forces like chewing, lip pressure, and even the tongue pushing against it. This is called pathologic tooth migration, and it is one of the most common complications of moderate to severe gum disease.⁴

The pattern is strikingly consistent. In one study of 44 patients with periodontitis-driven migration, about 91 percent showed facial flaring of their front teeth, and nearly 89 percent had developed gaps between incisors that were previously touching. Rotation and extrusion of teeth were also common.⁵ The teeth that migrated had significantly more attachment loss than neighboring teeth that stayed put, confirming that it is the destruction of the supporting tissue, not just the presence of inflammation, that allows the tooth to move.

This is important because many people first notice flaring before they realize they have serious gum disease. The cosmetic change is what sends them to the dentist, and the gum problem gets diagnosed afterward. If you are an adult whose front teeth seem to be spreading apart or tilting outward over time, a periodontal evaluation should be the first step, not braces.

Habits and Airway Patterns That Push Teeth Forward

In children and teenagers, flared teeth often trace back to oral habits or how the mouth functions day to day. Thumb sucking is the classic example: prolonged sucking puts steady forward pressure on the upper incisors and can create an open bite where the front teeth don’t meet. But the tongue can do the same thing. Tongue thrust, a retained infantile swallowing pattern in which the tongue pushes forward against or between the front teeth during every swallow, generates enough repetitive force to push incisors outward over time. The habit is sometimes linked to enlarged adenoids, chronic nasal congestion, or a prior thumb-sucking habit.⁶

Breathing pattern matters too. Chronic mouth breathing changes the resting position of the tongue and alters the balance of muscle forces around the dental arches. The tongue drops low, the cheeks press inward without the tongue’s counterbalancing force, and the upper arch narrows. That narrowing, combined with altered muscle activity, often leads to incisor flaring.⁷ Fixing the flare without addressing the underlying airway or muscle imbalance tends to produce relapse, because the same forces that pushed the teeth forward the first time are still at work.

Jaw Mismatches and Missing Back Teeth

Sometimes flaring is not about soft-tissue forces at all but about the shape and size of the jaws. A Class II malocclusion, commonly called an overbite, often features a lower jaw that sits too far back relative to the upper jaw. In that skeletal setup, the upper incisors may flare forward because there is nothing in front of them providing a stop. The upper jaw itself may also be positioned too far forward in some patients.⁸ Whether the problem is a retrusive lower jaw, a protrusive upper jaw, or a combination, the end result is the same: the incisors lack the normal lip-to-tooth and tooth-to-tooth forces that keep them upright.

Loss of back teeth can have a surprisingly similar effect. When molars are lost early and not replaced, the bite collapses in the back of the mouth. This shortens the vertical height of the face and shifts the biting forces forward. The upper incisors, now bearing loads they were never designed for, gradually tip outward.⁹ Treating the flared front teeth in this scenario without restoring the missing back teeth is futile; the same mechanical problem will push them forward again. The complication of managing bite collapse when adjacent teeth have already drifted into the empty space makes treatment planning more complex.¹⁰

Genetics and the Evolutionary Backstory

Your genes set the stage for flaring even if they don’t guarantee it. A twin study tracking dental arch traits from baby teeth through permanent teeth found that heritability estimates for features like arch width and arch length were consistently high, ranging from about 0.65 to 0.88 across most measurements.¹¹ That means the basic architecture of your jaw and arch shape is largely inherited. Overjet, the forward projection of the upper teeth past the lower teeth, was an exception, with environmental factors playing a larger role during the baby-teeth stage. But once adult teeth are in, the genetic blueprint reasserts itself.

Zooming out further, flaring may be partly a consequence of how human jaws have changed over millennia. Modern humans have smaller jaws than their ancestors, a shift linked to softer, more processed diets that require less chewing force. Tooth size has not shrunk at the same pace, creating a mismatch: teeth crowd into a jaw that is too small for them, and some end up pushed forward or out of alignment.¹² Crowding and protrusion are both expressions of that evolutionary squeeze.

How Flaring Affects Your Face and Lips

Flared upper incisors don’t just change your smile line; they reshape the soft tissue draped over them. The upper lip follows the teeth. When incisors sit forward, the lip projects further, and in more pronounced cases the lip may thin or fail to seal at rest, a condition called lip incompetence. Correcting the flare by retracting the incisors predictably pulls the lip back as well, with a strong correlation between how far the tooth moves and how far the lip follows.¹³

The degree of soft-tissue change depends on lip thickness and whether the lips were competent before treatment. In patients whose lips could not close comfortably over flared teeth, retracting the incisors produced more pronounced thinning and retraction of the lip than in patients who already had lip seal. The pattern of lip retraction was also more predictable in the incompetent-lip group.¹⁴ For people worried about how treatment will change their profile, this is genuinely useful information: if you currently struggle to close your lips over your teeth, expect a more dramatic change in lip posture once the teeth are retracted.

Treatment Starts With the Underlying Cause

No single treatment fits every case of flared teeth, and the most common mistake is jumping straight to braces without addressing what caused the flaring. If gum disease is the driver, periodontal treatment has to come first. Moving a tooth through already-compromised bone before the inflammation is controlled risks worsening the attachment loss and could result in tooth loss altogether.¹⁵ If posterior bite collapse is the root cause, the missing back teeth must be replaced, usually with implants or bridges, to re-establish vertical support before the front teeth are repositioned. If an airway or tongue-thrust habit is involved, addressing the functional issue alongside or before orthodontics prevents the teeth from flaring back out.

Once the cause is managed, the mechanical correction usually involves orthodontics. Traditional braces remain the most common approach, using archwire mechanics and sometimes temporary anchoring devices (mini-screws) to retract the incisors without tipping the back teeth forward in the process. Clear aligners are increasingly used for anterior retraction as well, and finite element studies suggest aligners can achieve meaningful tooth displacement for retraction cases, though the movement patterns differ from those of fixed braces.¹⁶ In practice, the choice between aligners and braces depends on the severity of the flare, whether extractions are needed to create space, and the complexity of the overall bite problem.

When Teeth Need to Be Removed

Retracting flared incisors requires space for them to move into. In mild cases, slight interproximal reduction (shaving tiny amounts of enamel between teeth) or minor expansion of the arch is enough. But in moderate to severe flaring with crowding, extracting premolars is often the most predictable way to create enough room. Orthodontic literature estimates that each 5 degrees of incisor proclination corresponds to roughly one millimeter of arch-length gain, and that about 10 degrees of correction (roughly two to three millimeters of forward movement) is a safe limit before bone coverage over the root becomes a concern. Beyond that, extractions or a combined approach is usually recommended to keep the roots safely within the bone.¹⁷

Surgical Correction for Skeletal Problems

When the flaring is rooted in a significant jaw-size discrepancy rather than just tooth position, braces alone may not be enough. Orthognathic surgery to reposition the upper jaw, lower jaw, or both is sometimes combined with orthodontics in severe skeletal Class II cases or in bimaxillary protrusion. For bimaxillary protrusion, the typical surgical-orthodontic approach involves extracting premolars, aligning the teeth, and then surgically setting back both jaws to reduce the overall protrusion.³ The procedure is major, but it can produce profile changes that orthodontics alone cannot achieve.

In cases where posterior bite collapse has been complicated by drifting and tilting of teeth into extraction sites, segmental osteotomy, a smaller surgical procedure that repositions a block of bone and teeth, is sometimes used in combination with braces to realign the posterior segments before addressing the flared incisors.¹⁰

Keeping Teeth Stable After Correction

Relapse is one of the biggest concerns after treating flared teeth, especially when the cause was periodontal disease. Even after successful retraction, the bone that was lost does not fully regenerate, and the teeth remain more mobile than teeth with intact support. For that reason, retention is not optional. Fixed retainers bonded behind the front teeth are common, and in severe cases, splinted crowns connecting several front teeth together, sometimes linked to posterior restorations, have been used to provide permanent stability and prevent any forward drift.¹⁸

In periodontitis-driven cases, gentle intrusive forces during treatment can push the teeth back into bone rather than just tipping them lingually, which helps improve their long-term prognosis.⁴ The approach requires close coordination between the orthodontist and periodontist, and treatment timelines tend to be longer than for straightforward orthodontic cases. Patients also need to commit to lifelong periodontal maintenance. Skipping recall visits and letting gum disease return is one of the fastest routes to re-flaring.

The Emotional Side of Flared Teeth

Flared teeth sit right in the middle of your smile, and the psychological impact can be significant. Research on adolescents has shown that both the health and appearance of teeth are meaningful predictors of self-esteem, with dental aesthetics ranking as one of the strongest factors in self-reported confidence levels.¹⁹ Adults are not immune to this either, particularly when flaring develops later in life from gum disease. The teeth you had as a young adult start to look different, gaps appear, and smiling becomes something you do with a closed mouth. That social withdrawal is often what finally drives people to seek treatment, sometimes more urgently than any functional complaint.

This matters practically because the emotional burden can sometimes push patients toward quick cosmetic fixes, like veneers over the flared teeth, without addressing the structural or periodontal cause. Veneers on unstable teeth are a temporary solution at best and a disaster at worst. If the underlying gum disease or bite problem continues to progress, the veneers will fail as the teeth keep moving. The impulse to fix the appearance quickly is understandable, but the treatment sequence matters: stabilize the foundation, correct the position, and then consider cosmetic refinements if needed.

Prosthetic Correction Without Braces

Not everyone with flared teeth is a candidate for orthodontics. In older adults with significant bone loss, moving teeth through compromised bone carries real risk. For these patients, prosthetic correction, reshaping the visible portion of the teeth with crowns or veneers to create the appearance of a more upright position, is sometimes the pragmatic choice. Biomechanical modeling of this approach has explored the stress distribution that results from placing crowns on proclined teeth, because the crown sits at an angle to the root and creates a lever-arm effect that concentrates force at the neck of the tooth.¹ The technique works best when the degree of flaring is mild to moderate. Severely flared teeth can’t be convincingly disguised with crowns alone without removing excessive tooth structure, which weakens the tooth and increases the risk of fracture or nerve damage.

In cases where prosthetic correction is combined with periodontal splinting, the crowns serve double duty: they improve appearance while physically connecting the teeth to share biting forces and resist further migration. This interdisciplinary approach, coordinating between a periodontist for gum treatment, a prosthodontist for the crowns, and sometimes an orthodontist for mild repositioning beforehand, tends to produce the most durable results in compromised dentitions.¹⁸

1
PubMed Central. Prosthetic Correction of Proclined Maxillary Incisors: A Biomechanical Analysis
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PubMed Central. Labiolingual Loading Biomechanics on Central Incisor Under Different Periodontal Conditions: A Finite Element Study
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PubMed Central. Bimaxillary protrusion: an overview of the surgical-orthodontic treatment
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PubMed. Pathologic tooth migration
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PubMed. Pathologic migration of anterior teeth in patients with moderate to severe periodontitis
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PubMed Central. Orofacial Myofunctional Therapy in Tongue Thrust Habit: A Narrative Review
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Seminars in Orthodontics. Stomatognathic function and orthodontic finishing: A narrative overview of functional principles for long-term stability
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ScienceDirect. Class II Malocclusions: Diagnostic and Clinical Considerations With and Without Treatment
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PubMed. Posterior bite collapse–revisited
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PubMed Central. Camouflage treatment of posterior bite collapse in a patient with skeletal asymmetry by using posterior maxillary segmental osteotomy
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PubMed Central. Genetic and environmental contributions to the development of dental arch traits: a longitudinal twin study
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Bulletin of the International Association for Paleodontology. Tooth evolution and its effect on the malocclusion in modern human dentition
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PubMed. Effect of lip thickness and competency on soft-tissue changes
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PubMed Central. Pattern of lip retraction according to the presence of lip incompetence in patients with Class II malocclusion
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The Journal of the American Dental Association. Differential Diagnosis and Management of Flared Maxillary Anterior Teeth
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PubMed Central. Comparative assessment of orthodontic clear aligner versus fixed appliance for anterior retraction: a finite element study
17
Elsevier / ScienceDirect (Seminars in Orthodontics). Space gaining in orthodontic treatment planning: The SPEED-L decision-making framework
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PubMed. An interdisciplinary treatment to manage pathologic tooth migration: a clinical report
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PubMed Central. Impact of Dental Disorders and its Influence on Self Esteem Levels among Adolescents