Introduction

Chin abnormalities, whether congenital (e.g., micrognathia, hemifacial macrosomia) or acquired (e.g., trauma, post-surgical deformity), can severely affect facial harmony and self-esteem. Traditional correction often involves orthognathic surgery or prosthetic implants, which are invasive and carry substantial recovery time and risks. In this context, the advent of injectable dermal fillers, particularly hyaluronic acid-based products, has provided a promising, minimally invasive solution for contouring the lower third of the face [1].

Hyaluronic acid (HA) is a biocompatible polysaccharide naturally found in human tissues. When injected as a filler, it provides volume, hydration, and structure, making it suitable for soft tissue augmentation. The use of HA fillers in chin reshaping, especially in patients with mild-to-moderate deformities or asymmetries, has seen a significant increase [2]. This systematic review seeks to synthesize current clinical evidence on the role of hyaluronic fillers in managing chin shape deformities in patients with maxillofacial abnormalities. It aims to evaluate the effectiveness, longevity, safety, and patient satisfaction of this treatment modality [3].

Craniofacial harmony plays a critical role in the perception of facial aesthetics and self-identity. Among the key structural elements that contribute to a well-balanced facial profile, the chin (mentum) occupies a pivotal position in defining the lower third of the face. Deformities or irregularities in chin projection, size, or contour whether congenital, developmental, or acquired can significantly alter facial symmetry and contribute to both aesthetic dissatisfaction and psychological distress in affected individuals (Sarver & Ackerman, 2003). Historically, correction of such abnormalities has relied heavily on invasive surgical procedures, including genioplasty and alloplastic implants [4].

However, these techniques, while effective, are associated with substantial risks, higher costs, and extended recovery times [5]. In recent years, minimally invasive aesthetic procedures have gained substantial traction in the field of facial contouring, particularly due to their favorable safety profiles, lower patient downtime, and growing patient preference for non-surgical alternatives. Among these, the use of hyaluronic acid (HA)-based dermal fillers for chin augmentation has emerged as a prominent method for addressing contour deficiencies and reshaping the mandibular region [6]. Hyaluronic acid is a naturally occurring glycosaminoglycan with excellent biocompatibility, hydrophilic properties, and the ability to restore volume and support in soft tissues [7]. When injected into the deep preperiosteal layer of the chin, HA fillers can effectively enhance projection, correct mild asymmetries, and restore facial balance, particularly in patients who may not be suitable candidates for surgical intervention.

In patients with maxillofacial abnormalities including conditions such as hemifacial macrosomia, mandibular hypoplasia, post-traumatic deformities, and iatrogenic defects chin irregularities are frequently observed as part of a broader skeletal and soft tissue imbalance [8]. For such individuals, traditional reconstructive approaches may not always be feasible due to underlying comorbidities, psychosocial factors, or personal preferences. In this context, HA fillers offer a reversible, customizable, and patient-friendly solution that can be tailored to the unique anatomical and aesthetic needs of each patient [9]. Moreover, because the results are temporary and adjustable, patients are afforded greater flexibility in achieving and refining their desired outcomes.

Despite the growing interest and widespread clinical use of HA fillers for chin reshaping, the literature on their specific application in patients with maxillofacial deformities remains scattered, heterogeneous, and largely based on anecdotal or case-based evidence. While several studies have demonstrated the general safety and efficacy of HA fillers in aesthetic chin augmentation [10-12], their performance in the context of complex maxillofacial pathology warrants further systematic investigation. Key questions remain unanswered regarding the long-term durability of results in structurally compromised tissues, the optimal injection techniques for various deformity types, the impact on patient-reported outcomes, and the comparative effectiveness relative to traditional surgical options [13].

Another important consideration is the potential role of HA fillers as adjuncts rather than alternatives to surgery. In selected cases, such as in preoperative planning or post-surgical contour refinement, fillers can serve as valuable tools in a multimodal treatment strategy. Their use may also facilitate better communication between clinician and patient regarding the expected aesthetic outcome, especially in situations where visual simulation and temporary correction can enhance shared decision-making [14].

The safety profile of hyaluronic fillers, particularly in the chin and mandibular region, must also be carefully scrutinized. Although generally regarded as safe, improper injection technique or lack of anatomical knowledge can result in complications ranging from bruising and edema to rare but serious vascular events such as occlusion or tissue necrosis [15]. This underscores the necessity of evidence-based guidelines and experienced injectors to maximize safety while optimizing aesthetic results, particularly in patients with abnormal anatomy where vascular and soft tissue patterns may be atypical or altered due to scarring, trauma, or congenital malformations.

Given the intersection of reconstructive necessity and aesthetic desire in this patient population, a systematic review of the available literature is both timely and warranted. The purpose of this review is to comprehensively evaluate the existing clinical evidence regarding the use of hyaluronic acid fillers for chin shape correction in individuals with maxillofacial abnormalities. Specifically, we aim to assess:

• The efficacy of HA fillers in achieving aesthetic and functional improvements in chin contour.
• Patient satisfaction and subjective outcome reporting following filler-based correction,
• The safety profile and incidence of complications in this specific patient population.
• The limitations, challenges, and potential future directions for integrating HA fillers into the broader maxillofacial treatment paradigm [16].

By synthesizing data from a variety of clinical studies including randomized controlled trials, observational cohorts, and case series we intend to provide clinicians, aesthetic practitioners, and maxillofacial surgeons with an evidence-based framework for considering hyaluronic fillers as a viable therapeutic option. In doing so, we also aim to identify knowledge gaps, standardize outcome assessment protocols, and contribute to the formulation of clinical guidelines that ensure safe and effective use of HA fillers in complex clinical contexts.

In summary, the evolving role of hyaluronic acid fillers in chin augmentation represents a promising frontier in both reconstructive and aesthetic medicine. Their minimally invasive nature, coupled with high levels of patient satisfaction and favorable safety outcomes, makes them an attractive modality for correcting chin deformities associated with maxillofacial abnormalities. However, the current state of evidence is fragmented, necessitating a rigorous and methodologically sound evaluation to better inform clinical decision-making. This review serves as a critical step toward that goal (table 1).

Table 1.  Use of Hyaluronic Acid Fillers in Chin Shape Correction in Maxillofacial Abnormalities

Methodology

Search Strategy

A comprehensive literature search was conducted in PubMed, Embase, Scopus, Web of Science, and Cochrane Library databases using the following keywords: "hyaluronic acid", "chin filler", "mentoplasty", "maxillofacial deformity", "non-surgical chin augmentation", and "soft tissue filler". The last search was conducted in July 2025.

 Eligibility Criteria

Inclusion criteria:

• Clinical studies (RCTs, cohort, case-control, case series).
• Use of HA fillers for chin correction in patients with maxillofacial deformities.
• Reported outcomes including aesthetic results, safety, and/or patient satisfaction.

Exclusion criteria:

• Animal studies.
• Purely aesthetic interventions in patients without maxillofacial pathology.
• Reviews, editorials, or studies lacking outcome data.

Data Extraction and Synthesis

Two reviewers independently screened titles, abstracts, and full texts. Data extracted included study design, sample size, patient demographics, filler type and volume, injection technique, outcome measures, follow-up duration, complications, and satisfaction scores.

 Quality Assessment

The Joanna Briggs Institute Critical Appraisal Checklists and the Newcastle-Ottawa Scale were used to assess study quality.

 Results

Study Selection and Characteristics

The initial database search yielded 364 records. After removal of duplicates and application of inclusion and exclusion criteria, a total of 18 studies were included in the final analysis. These consisted of 4 randomized controlled trials (RCTs), 6 prospective cohort studies, and 8 retrospective case series. The cumulative sample included 729 patients (aged between 17 and 64 years), with a slight female predominance (62%). All studies reported on patients with maxillofacial abnormalities involving chin deformity ranging from congenital microgenia and hemifacial macrosomia to post-traumatic and iatrogenic deformities.

Filler Type and Injection Technique

The majority of studies used high G-prime hyaluronic acid (HA) fillers specifically formulated for deep tissue and structural support, including Juvederm Voluma, Restylane Lyft, Teosyal Ultra Deep, and Belotero Volume.

·         Injections were most commonly administered using a blunt cannula (61%) or sharp needle (39%), depending on practitioner preference and anatomical considerations.

·         Techniques varied between linear retrograde threading, cross-hatching, and bolus injection into the preperiosteal or supraperiosteal plane, targeting the pogonion and menton regions.

·         Average injected volume per session ranged from 0.7 mL to 2.5 mL, depending on the degree of deformity and desired projection.

Aesthetic Outcomes and Objective Improvement

Across all studies, aesthetic outcomes were measured using standardized scales such as:

·         Global Aesthetic Improvement Scale (GAIS).

·         FACE-Q satisfaction questionnaires.

·         3D photographic and morphometric analysis.

Findings

·         89% of patients demonstrated visible improvement in chin projection, with more harmonious lower facial contours.

·         In 10 studies that used GAIS, 85% of patients were rated as “very much improved” or “much improved” by both clinician and patient assessments.

·         3D imaging showed an average forward projection gain of 3.2 mm, and chin width improvement of 1.4 mm, sustained over 6–12 months.

·         Patients with mild to moderate deformities showed the most significant benefit, while severe skeletal discrepancies required combined surgical interventions.

Patient Satisfaction

Patient-reported outcomes were reported in 14 studies. The most common tools included:

·         Visual Analog Scale (VAS) for satisfaction.

·         FACE-Q modules for facial confidence and social functioning.

Key results

·         86% of patients rated their satisfaction as "high" or "very high".

·         92% of patients reported feeling more confident in social interactions after treatment.

·         Repeat procedures were requested by 68% of patients within 12–18 months to maintain results.

Longevity of Results

The duration of visible aesthetic improvement ranged between 8 to 18 months, with variability depending on the filler used, injection depth, and patient metabolism.

·         Studies using Juvederm Voluma and Restylane Lyft reported the longest durability, with some patients maintaining results up to 20 months.

·         In 5 studies with longitudinal follow-up, 70% of patients required touch-up sessions within the first year.

Table 2. Summary of Findings from Included Studies)

Safety and Adverse Events

Adverse events were classified as mild (transient), moderate (requiring medical treatment), or severe (irreversible or life-threatening).

Overall complication rate was low:

·         Transient swelling: 22%

·         Localized bruising: 15%

·         Mild pain or tenderness at injection site: 11%

·         Lumpiness or uneven texture: 4% (resolved spontaneously or with massage)

No severe complications such as:

·         Vascular occlusion.

·         Skin necrosis.

·         Infection.

·         Nerve damage.

were reported in any of the included studies.
Two studies reported minor asymmetry requiring touch-up injections at 2 weeks post-treatment.

Comparative Analysis: HA Fillers vs. Surgical Alternatives

Three studies included a comparison arm involving patients who underwent surgical genioplasty or chin implants.

Findings

·         HA filler group had:

o    Lower downtime (1–2 days vs. 7–14 days).

o    Faster return to work/social activity.

o    Higher early-phase satisfaction scores.

·         Surgical group had:

o    More permanent results.

o    Greater projection in patients with major skeletal deficiency.

·         Long-term satisfaction was comparable at 12 months, though cost-effectiveness favored surgical correction for lasting change (Table 3).

Table 3. Comparative Study Summary Table

Use in Special Populations

Some studies specifically reported on HA filler use in:

·         Post-traumatic chin deformities (4 studies): Safe and effective in masking contour irregularities.

·         Patients with hemifacial macrosomia (2 studies): Partial correction achieved; asymmetry improved but skeletal mismatch remained.

·         Elderly patients with resorptive bone loss (2 studies): Subtle enhancement, but risk of overcorrection due to reduced soft-tissue elasticity noted (Table 4).

Table 4. Summary of Results