Short Upper Lip Length Versus Skeletal Overgrowth

Anatomy of Smile Aesthetics: Upper Lip Length and the Maxilla

A balanced smile involves a harmonious relationship between the upper lip, the maxillary gingiva (upper gum tissue), and the maxillary teeth. In clinical practice, excessive gingival display—frequently described by patients as a gummy smile—is defined as the visibility of more than two to three millimetres of gum tissue during a full, unforced smile. Understanding whether this presentation is driven by soft tissue dimensions or underlying skeletal architecture requires examining two key structures: the philtrum of the upper lip and the underlying maxilla (upper jaw bone).

The anatomical length of the upper lip is measured vertically from subnasale (the base of the nose beneath the nasal septum) to stomion superius (the lowest midpoint of the upper vermilion border). In young adult females, normal lip length at rest typically ranges between 18 and 22 millimetres, whereas in adult males, it ranges between 20 and 24 millimetres. The vertical position of the maxilla dictates the base upon which this soft tissue rests. When evaluating a short upper lip gummy smile, clinicians must distinguish between a genuine deficiency in vertical soft tissue length and an overdeveloped maxilla that positions otherwise normal lips too high relative to the dental arch.

Underlying Causes: Soft Tissue Variations Versus Skeletal Discrepancies

Excessive gingival display is multifactorial. A primary soft-tissue cause is true anatomical lip deficiency, where the upper lip failed to develop sufficient vertical height during craniofacial maturation. In other instances, the lip length is normal at rest, but hyperfunction of the elevator muscles—specifically the levator labii superioris alaeque nasi, levator labii superioris, and zygomaticus major—causes the lip to translate excessively upward upon smiling, exposing an exaggerated band of gingiva.

Conversely, skeletal discrepancies arise from vertical maxillary excess (VME), an overgrowth of the maxilla in the downward (vertical) dimension. When the upper jaw is vertically elongated, the alveolar process carries the teeth and gingiva further inferiorly, creating disproportion relative to facial thirds. In these cases, even a lip of standard or above-average length cannot cover the dentoalveolar complex at rest. Environmental and developmental factors such as prolonged mouth breathing, chronic nasal airway obstruction, and childhood pacifier habits can alter facial growth vectors, accentuating vertical jaw discrepancies.

Clinical Presentation: Recognising a Short Upper Lip Gummy Smile

Patients presenting with vertical maxillary discrepancies or shortened upper lips exhibit distinct visual and functional features. A key sign is lip incompetence (interlabial gap at rest), where the lips cannot gently close together without conscious contraction of the mentalis muscle (the chin muscle). This mentalis strain creates a characteristic puckering or 'orange-peel' appearance (peau d'orange) on the chin during attempted lip closure.

In patients with true short upper lip length, the gingival exposure is often accompanied by an elevated resting incisal show, meaning more than 3 to 4 millimetres of the upper incisors is visible when the mouth is relaxed. In pure muscular hypermobility, resting tooth exposure may appear normal, but dynamic smiling creates a sudden, dramatic upward contraction. Patients with vertical maxillary excess often present with an elongated lower facial third, a narrow upper dental arch, and sometimes an anterior open bite, where the front teeth fail to overlap vertically.

Diagnostic Evaluation, Cephalometrics, and Differential Diagnosis

Accurate diagnosis requires a structured clinical assessment combined with advanced radiographic imaging. The orthodontist or oral and maxillofacial surgeon begins with dynamic facial analysis, measuring philtrum height at rest, lip mobility during a posed smile, and interlabial distance. Clinical photographs capture resting and animated views from frontal and profile angles, ensuring subtle soft-tissue asymmetries are recorded alongside dentogingival proportions.

Standard diagnostic protocols include lateral cephalometric radiography and, where indicated, Cone Beam Computed Tomography (CBCT). Cephalometric tracing evaluates specific hard- and soft-tissue landmarks, comparing measurements such as the lower anterior facial height, maxillary height, and the angle of the upper incisors against established population norms. Differential diagnosis must systematically rule out altered passive eruption (where gingival tissue fails to recede to the cementoenamel junction during tooth emergence) and dentoalveolar extrusion (where teeth over-erupt secondary to lack of opposing contact).

Classification Systems for Excessive Gingival Display

In maxillofacial and orthodontic literature, vertical maxillary excess is commonly categorised into three distinct degrees of severity to guide intervention. Degree I represents mild vertical excess with 2 to 4 millimetres of gingival show beyond the aesthetic baseline; Degree II represents moderate excess with 4 to 8 millimetres of display; and Degree III denotes severe skeletal overgrowth exceeding 8 millimetres, almost invariably accompanied by significant lip incompetence and marked facial elongation.

Soft tissue variations are classified according to lip morphology and muscular dynamics. Clinicians categorise lips as anatomically short (reduced subnasale-to-stomion distance), hypermobile (vertical excursion greater than the standard 6 to 8 millimetres during smiling), or composite (combining structural deficiency with muscular hyperactivity). Establishing the precise classification is critical: attempting to treat a skeletal Degree III deformity with soft-tissue procedures alone will invariably lead to poor aesthetic balance and potential functional compromise.

Evidence-Based Treatment Modalities Compared

Treatment selection depends directly on whether the primary underlying cause is skeletal, muscular, or anatomical soft-tissue deficiency. For moderate to severe vertical maxillary excess (Degrees II and III), orthognathic surgery via a Le Fort I osteotomy remains the gold standard. During this procedure, the maxilla is surgically detached, a precise vertical strip of bone is removed (superior repositioning or impaction), and the jaw is rigidly fixated with titanium plates, physically raising the teeth and gums.

For mild skeletal excess or dentoalveolar extrusion, orthodontic intrusion using temporary anchorage devices (TADs or skeletal mini-screws) provides a non-surgical alternative, moving the upper anterior teeth bodily upward into the alveolar bone. If the discrepancy is purely muscular, temporary neuromodulator injections (such as botulinum toxin) into the levator muscles reduce hypermobility for three to six months. For anatomical lip deficiencies or mild-to-moderate muscular display, surgical lip repositioning—a mucosal resection within the maxillary vestibule—can restrict upward lip translation without altering bone.

Step-by-Step Clinical and Surgical Procedures

For orthodontic intrusion with temporary anchorage devices, the appointment begins with local anaesthesia around the buccal cortical bone between tooth roots. The orthodontist inserts titanium mini-screws directly into the bone using a precision hand-driver. Elastomeric chains or nickel-titanium springs are then connected from the screws to the orthodontic archwire, applying a light, continuous vertical force of 15 to 25 grams per tooth to gently intrude the dentition over several months.

In surgical lip repositioning, performed under local anaesthesia, a partial-thickness strip of mucosa is excised from the maxillary labial vestibule, superior to the mucogingival junction. The inferior and superior borders of the incision are then sutured together with fine, absorbable stitches, effectively shortening the depth of the vestibule and limiting how high the upper lip can pull upward during smile animation.

A Le Fort I maxillary impaction is performed under general anaesthesia in a hospital setting. The surgeon makes a horizontal incision across the upper gums, exposes the maxillary bone, and performs controlled horizontal bone cuts. After removing the pre-calculated vertical bone segment, the maxilla is repositioned superiorly and secured with mini-plates. The soft tissues are then meticulously closed using an alar base cinch suture to control nasal widening and a V-Y advancement closure to optimise upper lip vermilion fullness.

Recovery, Postoperative Aftercare, and Normal Milestones

Post-procedure recovery varies widely by modality. Following mini-screw placement or lip repositioning, patients experience mild local soreness, mild swelling (oedema), and mucosal tightness for three to seven days, typically managed with standard over-the-counter analgesics such as paracetamol or ibuprofen. Patients are instructed to consume a soft diet, avoid vigorous physical activity, and maintain meticulous oral hygiene using warm salt-water rinses or 0.12% chlorhexidine gluconate mouthwash, avoiding direct brushing on surgical sites.

Recovery from orthognathic Le Fort I surgery requires a more extensive timeline. Facial swelling and minor bruising peak at 48 to 72 hours and subside over two to three weeks. A non-chew, liquid-to-pureed diet is mandatory for the first four to six weeks to allow osseous healing. Mild nasal congestion and transient numbness of the upper lip and palate (paraesthesia) are normal and gradually resolve as neurosensory pathways recover over several months.

Complications, Red Flags, and When to Seek Immediate Care

While routine side effects like manageable swelling and slight bruising are expected, clinicians and patients must recognise signs of adverse complications. In orthodontic intrusion, excessive force can trigger external apical root resorption (shortening of tooth roots) or loss of pulp vitality. Lip repositioning carries risks of suture dehiscence (unravelling of stitches), localized infection, scar tissue formation, or partial relapse as soft tissues adapt over time.

For major orthognathic interventions, urgent clinical evaluation is necessary if severe red flags emerge. Immediate medical attention must be sought in the event of brisk or uncontrolled intraoral bleeding, sudden difficulty breathing, rapidly spreading facial swelling accompanied by erythema and high fever, or unexpected mobility of the maxilla. Patients experiencing sudden, severe pain unalleviated by prescribed medication, or persistent, worsening purulent discharge around mini-screws or surgical incisions, should contact their surgical team immediately.

Long-Term Stability, Retention, and Oral Health Maintenance

The long-term stability of gummy smile correction depends heavily on maintaining skeletal and dentoalveolar equilibrium. Following orthodontic intrusion, rigid retention protocols—combining bonded lingual retainers with vacuum-formed clear retainers worn nightly—are critical to prevent vertical rebound. Patients must adhere to regular dental hygiene visits to prevent marginal gingival inflammation, which can falsely exaggerate gingival display.

Lifestyle and dietary factors also influence overall outcomes. In South Asian communities, the habitual use of paan, gutka, or areca nut poses severe risks to periodontal health, promotes mucosal fibrosis, and compromises soft-tissue elasticity, undermining both surgical and non-surgical aesthetic results. Patients are strongly advised to cease all forms of smokeless and smoked tobacco. Long-term functional success is reinforced through myofunctional exercises where indicated, helping establish competent, unforced lip seal during normal nasal breathing.

Evidence and further reading

Contemporary international consensus in orthodontics and periodontology emphasizes that successful treatment of excessive gingival display depends entirely on etiology-specific therapy. Systematic reviews in the Journal of Clinical Periodontology and the International Journal of Oral and Maxillofacial Surgery confirm that Le Fort I impaction provides the most stable, predictable outcomes for true vertical maxillary excess, while temporary anchorage devices offer a clinically viable alternative for moderate dentoalveolar discrepancies.

Professional bodies, including the British Orthodontic Society, the American Association of Orthodontists, and the European Federation of Periodontology, advocate comprehensive multidisciplinary assessment before initiating treatment. Research indicates that combining soft-tissue and hard-tissue measurements prevents misdiagnosis, ensuring patients are not subjected to irreversible skeletal procedures for primary muscular hypermobility, nor offered transient soft-tissue treatments for significant skeletal discrepancies.