Non-surgical camouflage of severe skeletal Class II with protrusion and gummy smile using 3D planning, temporary anchorage device, and botulinum toxin: A case report

INTRODUCTION

Facial esthetics remains one of the most common motivations for patients seeking orthodontic care. Among various dentofacial discrepancies, skeletal Class II malocclusion, particularly when combined with excessive gingival display, poses a significant challenge in both diagnosis and treatment planning. These cases not only affect the sagittal and vertical relationships of the jaws but also compromise smile harmony and self-confidence.^[1]

Orthognathic surgery is often recommended for severe skeletal discrepancies with vertical maxillary excess. However, when surgical options are not feasible, whether due to financial, psychological, or personal reasons, non-surgical camouflage treatment can be a practical alternative. The development of temporary anchorage devices (TADs), such as miniscrews, has expanded the boundaries of orthodontic correction by providing absolute anchorage for controlled tooth movement, independent of patient compliance.^[2-5]

In the present case, the patient exhibited a severe skeletal Class II malocclusion with bimaxillary protrusion and an asymmetrical gummy smile more pronounced on the right side. On detailed clinical evaluation, the uneven gingival display was attributed to a hyperactivity of the upper lip elevator muscles on the right, notably the levator labii superioris. This muscular imbalance resulted in excessive gingival exposure while smiling on the right side, while the left side remained relatively balanced.

Orthodontic camouflage treatment was carried out using miniscrew-supported en masse retraction and anterior torque control, which significantly improved the patient’s facial profile and occlusion. However, despite the successful dental and skeletal correction, the asymmetrical gummy smile persisted. To address this esthetic issue, a targeted unilateral injection of botulinum toxin type A was administered to the hyperactive right upper lip elevator complex. The advantages of botulinum toxin therapy include its simplicity, reversibility, minimal discomfort, and relatively low risk of complications. However, its effects are temporary (lasting approximately 4–6 months) and require repeat injections to maintain results. Several studies and case reports have demonstrated the effectiveness of botulinum toxin injections for gummy smile correction, particularly in cases of muscular etiology or mild vertical maxillary excess. The Yonsei point, an anatomical landmark where multiple upper lip elevator muscles converge, has been widely used as an injection site, offering predictable results with minimal risk of adverse effects. This approach reduced muscle contraction on the affected side, resulting in a more symmetrical and esthetically pleasing smile line.^[6-8]

This case report demonstrated how a combined approach using skeletal anchorage systems and selective botulinum toxin injection can be effectively used to manage complex skeletal and soft-tissue esthetic concerns, including an asymmetric gummy smile due to muscle hyperfunction. It underscores the importance of individualized diagnosis and interdisciplinary care in achieving optimal outcomes in borderline surgical orthodontic cases.

CASE REPORT

The 38-year-old patient came to our clinic with several chief complaints, including lip incompetence, a gummy smile on the right side, and protrusion.

Intraorally, the patient is skeletal class II with class I molar, big overjet, protrusion of upper and lower incisors, deep curve spee, spacing on the right side of the upper because of the extraction 1^st premolar in another clinic, and missing 1 lower incisor. Extraorally, the patient had a convex profile, lip incompetence, the patient’s smile revealed 4 mm of gums with a hypermobile lip on the right side, proclined the upper incisors, and a gummy smile, but the upper lip of the patient was asymmetrical during smiling. The pre-treatment radiographies showed proclined upper incisors, deep curve spee, spacing [Figures 1 and 2, Table 1].

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Figure 1:

Intraoral initial pictures.

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Figure 2:

Extraoral images and X-rays, pre-treatment.

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Treatment execution

Stage 1 – Initial alignment and leveling (0–4 months)

• Pre-treatment 2D and 3D simulations were comprehensively performed as part of the digital diagnostic workflow to facilitate consultation with the patient and the patient’s family, allowing them to visualize the proposed treatment objectives and expected outcomes. These simulations were also utilized to verify the post-incisor position (PIP), assess facial and dental harmony, and to predict the most favorable biomechanics required to achieve controlled tooth movement and optimal esthetic results [Figure 3].

  

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  Figure 3:

  Pre-treatment 2D and 3D simulations were utilized to verify the post-incisor position (PIP) and to plan the optimal biomechanics for tooth movement.

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• Full fixed appliance placement in both upper and lower arches (MBT Bracket system (McLaughlin – Bennett – Trevisi) (MBT) prescription, 0.022 × 0.028-inch slot)

• Light continuous archwires (0.014-inch and 0.016-inch NiTi) for initial alignment, resolving minor crowding and leveling arches

• Early insertion of skeletal anchorage: two inter-radicular miniscrews between upper second premolars and first molars bilaterally; two buccal shelf miniscrews distal to mandibular second molars

• Goal: prepare arches for space closure and establish stable anchorage early.

Stage 2 – Space closure and intrusion mechanics (4– 16 months)

• Stainless steel archwires (0.017 × 0.025-inch) in both arches for rigid control

• Maxillary space closure: sliding mechanics from inter-radicular miniscrews to hooks on the archwire, applying retraction force through the center of resistance of the anterior segment to achieve bodily retraction and intrusion of upper incisors

• Mandibular space closure: power chains from buccal shelf miniscrews to canines bilaterally, combined with reverse curve of Spee in the archwire to level the curve and reduce deep bite

• Continuous monitoring of incisor torque to prevent excessive retroclination. Continuous closing of the remaining space, monitoring of molar root position, and incisor torque to prevent excessive retroclination using the RAW (Reverse Arch Wire) technique.

Stage 3 – Finishing and detailing (16–21 months)

• Final arch coordination and occlusal settling with light elastics as needed

• Interproximal reduction on upper anterior teeth to correct the Bolton discrepancy due to a missing mandibular incisor

• Fine adjustments to ensure ideal overjet, overbite, and canine/molar relationships [Figures 4 and 5].

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Figure 4:

Treatment progress – retraction of upper and lower anterior teeth using 4 miniscrews.

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Figure 5:

Treatment progress: The remaining spaces were closed using the Reverse Arch Wire (RAW) technique - detailing and finishing.

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Stage 4 – Botulinum toxin application (21–22 months)

• Following orthodontic debonding, a unilateral botulinum toxin type A injection was administered at the Yonsei point on the right upper lip elevator complex

• Rationale: Reduce excessive gingival display caused by hyperactivity of the right levator labii superioris group

• Dosage: Conservative unilateral dose (2.5–3 units) to minimize risk of asymmetry and speech changes.

Stage 5 – Retention phase (22–24 months and beyond)

• Delivery of removable clear thermoplastic retainers for both arches

• Instructions for full-time wear for the first 6 months, then nighttime wear thereafter.

Follow-up appointments are scheduled at 3-month intervals to monitor retention and assess the longevity of botulinum toxin effects.

Treatment results

Following 24 months of active orthodontic treatment, all treatment objectives were accomplished. The patient demonstrated a well-aligned dental arch with complete space closure and effective retraction of both upper and lower incisors, contributing to a markedly improved facial profile. The overbite and overjet were brought within normal limits, resulting in a stable and functional Class I occlusion. Importantly, the previously noted unilateral gummy smile was significantly reduced, enhancing smile symmetry and overall facial harmony. Superimposition of pre- and post-treatment records, along with cephalometric analysis, revealed notable improvements in incisor inclination and soft-tissue contour. To preserve the achieved occlusal and esthetic outcomes, a removable clear aligner appliance was provided for post-treatment retention [Figures 6-9 and Table 1].

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Figure 6:

Extraoral images and X-rays post-treatment.

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Figure 7:

Intraoral post-treatment pictures.

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Figure 8:

Extraoral pictures (Smile), pre-treatment, after orthodontic treatment, post-treatment, after botulinum toxin.

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Figure 9:

Superimposition before and after treatment.

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DISCUSSION

Management of adult patients with severe skeletal Class II division 1 malocclusion, lip protrusion, and gummy smile poses substantial challenges, particularly when surgical correction is not feasible due to financial or personal constraints. In such cases, non-surgical camouflage approaches, when carefully planned and executed, can provide significant esthetic and functional improvements.^[9] This case report illustrates a multidisciplinary strategy that combines 3D digital planning, skeletal anchorage mechanics, and soft-tissue modulation using botulinum toxin to achieve a successful non-surgical outcome.

Gummy smile etiology is multifactorial, involving skeletal, dentoalveolar, and muscular components. When skeletal or dentoalveolar factors are ruled out or corrected, such as in this case, the remaining asymmetry is often attributed to hyperactivity of the upper lip elevator muscles, including the levator labii superioris, levator labii superioris alaeque nasi, and zygomaticus minor. In this patient, hyperactivity was localized to the right upper lip elevator complex, resulting in an excessive gingival display on the right side only, despite bilateral dental alignment. This type of presentation is relatively uncommon and can be challenging to correct surgically without overcorrection on the contralateral side.

The use of digital 2D and 3D simulation at the planning stage improved patient communication and allowed for biomechanical visualization of expected changes. This modern approach enhances informed consent and improves patient cooperation, especially when the proposed plan diverges from surgical expectations.

The use of TADs, including inter-radicular and buccal shelf miniscrews, enabled effective anterior retraction, vertical control, and intrusion of the upper anterior segment, which was critical in addressing both the protrusion and the gummy smile. Intrusion mechanics, when performed from skeletal anchorage placed at an optimized height and vector, have been shown to yield favorable vertical changes without compromising incisor torque or periodontal health. The reverse curve of Spee and segmented retraction from buccal shelf screws in the mandible facilitated the correction of the deep curve and lower anterior crowding, despite the missing incisor and asymmetrical extraction pattern. RAW (Reverse Arch Wire) mechanics were employed to close all residual spaces without the use of hooks or miniscrews, thereby simplifying the biomechanics and maintaining effective torque control of both upper and lower incisors.

The unique feature of this case was the unilateral excessive gingival display, attributed to hyperactivity of the right upper lip elevator muscle. While dental and skeletal components were corrected through orthodontics, the residual soft-tissue imbalance was esthetically unacceptable. Botulinum toxin injection at the Yonsei point selectively targeted the hypermobile right upper lip, producing a more symmetrical smile without the need for surgical lip repositioning. This aligns with previous reports supporting the efficacy of botulinum toxin in cases of hypermobile lip or mild vertical maxillary excess, especially when asymmetry is involved.

Botulinum toxin type A has emerged as a minimally invasive and effective tool to manage such cases by temporarily reducing the contractility of targeted muscle groups. Its use in esthetic dentistry and orthodontics, especially in treating hypermobile upper lips or mild vertical maxillary excess, has gained significant support in recent literature. In this case, a targeted unilateral injection at the Yonsei point, a well-documented anatomical location where multiple upper lip elevator muscles converge, was chosen to address the asymmetric activity without compromising the balance of the contralateral side.^[6]

The Yonsei point technique has been shown to achieve a predictable reduction in upper lip elevation with a lower risk of unwanted effects such as upper lip flattening or asymmetry. The dosage, typically ranging from 2.5 to 5 units per site, must be carefully titrated based on muscle strength, smile exposure, and individual anatomy. In this case, a conservative approach with unilateral dosing achieved the desired result without the need for surgical lip repositioning or extensive soft-tissue manipulation.^[10]

However, the effects of botulinum toxin are temporary, lasting approximately 4–6 months, and patients must be counseled regarding the potential need for repeat injections to maintain the esthetic benefit. Nevertheless, it presents a low-risk, reversible option for addressing soft-tissue discrepancies in cases where permanent procedures are not desired or are contraindicated.^[11,12]

This case reinforces the importance of a comprehensive, interdisciplinary assessment that integrates skeletal, dental, and soft-tissue components, particularly in borderline cases where surgery is declined. By utilizing modern anchorage systems and minimally invasive adjuncts such as botulinum toxin, clinicians can offer meaningful alternatives to traditional surgical approaches.

CONCLUSION

This case report demonstrated that non-surgical camouflage treatment, when carefully planned and supported by skeletal anchorage and digital simulation, can provide effective correction of severe skeletal Class II malocclusion with bimaxillary protrusion and an asymmetric gummy smile. The combination of mini screw based biomechanics and targeted unilateral botulinum toxin injection successfully addressed both the dental and soft-tissue components of the patient’s chief complaints. This interdisciplinary, minimally invasive approach represents a viable and esthetically satisfying alternative to orthognathic surgery for selected adult patients with similar clinical presentations.