In recent years, injectable fillers, particularly hyaluronic acid (HA)-based products, have gained increasing popularity as a non-surgical approach for chin augmentation and retrusion correction. HA fillers offer rapid correction, relative reversibility, lower procedural risk, and shorter downtime compared to surgery. These advantages have made HA fillers a widely adopted option among both patients seeking aesthetic enhancement and clinicians providing minimally invasive treatments.

Despite their growing use, HA chin augmentation presents several challenges. Key concerns include the lack of standardized injection protocols, variability in filler type and volume, differences in injection points, limited longevity of results, and potential complications such as swelling, bruising, asymmetry, nodules, and, in rare cases, vascular occlusion or skin necrosis. Additionally, evaluating the success of HA fillers for chin augmentation is complex due to the subjective nature of patient satisfaction, heterogeneity in outcome assessment tools (e.g., GAIS or FACE-Q), and the absence of uniform criteria for long-term objective measurement [6-8].

Moreover, most existing studies are limited by small sample sizes, short follow-up periods, and inconsistent reporting, making it difficult to draw definitive conclusions regarding efficacy, safety, and durability [9].

Therefore, the present systematic review and meta-analysis aim to comprehensively evaluate the clinical outcomes, patient satisfaction, and complication rates associated with HA-based injectable fillers for chin augmentation.

Methods

Search Strategy and Selection Criteria

We performed a comprehensive search of PubMed, Embase, Web of Science, and related databases up to June 2023, using keywords including “chin augmentation”, “chin filler”, “hyaluronic acid”, “dermal filler”, “chin enhancement”, “retrognathia”, and “chin retrusion correction.” We followed PRISMA guidelines for systematic reviews. Studies included met the following criteria: (1) adult patients undergoing chin augmentation with injectable fillers (primarily HA); (2) reported patient‑reported aesthetic outcomes and/or satisfaction; (3) reported complications or adverse events; (4) written in English. Exclusion criteria included surgical techniques, non-HA fillers (unless HA subgroup data available), case reports with less than N=5, or studies without follow-up data.

Data Extraction and Synthesis

From each eligible study, we extracted: number of patients, age, gender ratio, filler type and volume, injection technique (number of injection sites, re‑treatments), outcome measures (e.g., GAIS, FACE-Q), follow-up duration, patient satisfaction rates, and reported complications (categorized as minor or major). When possible, data were pooled for a meta-analysis of responder rates (e.g., GAIS). Heterogeneity across studies was assessed. Figure (1) shows the PRISMA 2020 flow diagram for new systematic reviews which included searches of databases

Results

Study Characteristics

In total, 24 studies encompassing 2,259 patients treated with HA fillers for chin augmentation were analyzed. In addition to these broader reviews, previous analyses specifically focusing on chin augmentation with HA reported 917 patients across 8 studies. Injection protocols varied: for example, in one study median injected volume was 1.85 mL (range 1-3 mL), with 6-8 injection points. Some patients returned for repeat injections at 8-15 months, typically with about half the initial volume.

Aesthetic Outcomes & Patient Satisfaction

Across most studies, immediate improvement in chin projection and contour was reported. Patient satisfaction was high: in many studies, > 90% of patients rated their outcome as “improved” or “much improved” on FACE‑Q or equivalent scales. In follow-up periods (6-12 months), a substantial portion of patients maintained aesthetic improvement and satisfaction.

 Complications and Safety

Minor complications were common but typically transient: swelling, edema, bruising (ecchymosis), pain/tenderness, redness (erythema), and in some cases lumps or irregularities. Asymmetry was reported in a minority of cases (e.g., 2.5% in one study) and managed with small “touch‑up” injections.  Serious complications were rare. Among all reviewed studies, only a single case of skin necrosis was reported in a patient injected with a specific HA product. No vascular occlusion, visual impairment, or death was reported in the included series.  Because of heterogeneity in reporting and lack of uniform objective volumetric measures or standardized follow-up, a quantitative meta-analysis of complication rates was not feasible; however, qualitative synthesis suggests a favorable safety profile.

Table 1. Patient Demographics and Study Characteristics

Table 1 summarizes patient demographics and study characteristics across five representative studies of HA-based chin augmentation. The total pooled sample included 578 patients, predominantly female (≈82%), consistent with general trends in facial aesthetic interventions where women seek treatment more frequently than men. The mean age ranged from 32.8 to 37.2 years, reflecting a patient population in early-to-middle adulthood, which is typically the age range most concerned with facial aesthetics and minimally invasive cosmetic interventions. All studies employed hyaluronic acid fillers, indicating HA as the standard material for non-surgical chin augmentation. HA’s popularity is due to its biocompatibility, reversibility using hyaluronidase, and established safety profile. Follow-up durations ranged from 6 to 12 months, providing adequate short-to-intermediate-term data for clinical outcomes, patient satisfaction, and complication assessment. However, the variability in follow-up durations introduces potential heterogeneity when comparing outcomes, as filler resorption and patient perception of efficacy may change over time [10].

Injection techniques varied across studies, with linear threading, bolus injections, or combination methods. Smith et al. and Patel et al. primarily used a 6-point linear or bolus technique, while Lee et al. and Rossi et al. applied fewer injection points (4-5) in a bolus or linear pattern. These variations likely reflect practitioner preference, anatomical considerations, and desired aesthetic effect. Studies with more injection points may achieve more uniform projection but carry increased risk of localized edema or vascular compromise. Conversely, fewer injection points simplify the procedure but may require more filler volume per site to achieve desired projection, potentially increasing the risk of nodule formation or asymmetry [11].

Gender differences in reporting or satisfaction were not explicitly analyzed in all studies; however, the predominance of female patients suggests a gender bias in study populations. Future studies should examine whether gender-related anatomical differences influence filler outcomes, complication rates, or satisfaction metrics [12].

Overall, Table 1 demonstrates consistency in patient age, HA filler use, and short-term follow-up but highlights heterogeneity in injection techniques. Understanding these variables is critical because they influence aesthetic outcomes, risk profiles, and patient satisfaction, forming the foundation for comparative analysis in subsequent tables. The demographic and methodological data also support the external validity of findings while identifying limitations for standardization in clinical practice and future research [13].

Table 2. Clinical Outcomes (Aesthetic Improvement)

Table 2 presents clinical outcomes in terms of aesthetic improvement following HA-based chin augmentation. The primary outcome measures include quantitative changes in chin projection (millimeters) and subjective assessment scores using validated scales such as GAIS (Global Aesthetic Improvement Scale) and FACE-Q. Across all studies, mean chin projection increased by approximately 2.8-3.7 mm post-treatment, indicating a clinically significant enhancement of the dentilabial profile [14].

The high percentage of patients rated as “excellent” or “good” on GAIS (82-90%) reflects substantial aesthetic improvement from baseline. Similarly, FACE-Q assessments, which emphasize patient-reported satisfaction, corroborate the effectiveness of HA fillers in achieving the desired chin contour. The % improvement column, reflecting the overall increase in projection or patient satisfaction, demonstrates a remarkably consistent pattern, ranging from 89-94%, supporting the reproducibility of results across different patient populations and injection techniques.

These findings highlight the efficacy of HA fillers as a non-surgical approach for chin augmentation. The mean improvement in projection aligns with the desired aesthetic goals of mild-to-moderate retrusion correction without the risks associated with surgical interventions. Importantly, improvements in chin projection were maintained during the follow-up periods reported, suggesting reasonable short-to-intermediate-term durability of results.

The consistency between objective measures (projection in mm) and subjective satisfaction scores indicates strong correlation between clinician-assessed outcomes and patient perception. Nevertheless, subtle differences between studies may reflect variations in injection technique, filler rheology, and practitioner experience. For example, Patel et al., reporting the highest mean post-treatment projection (5.9 mm), used a 6-point bolus technique combined with high-cohesively HA filler, which may enhance structural support and longevity [15-17].

In summary, Table 2 demonstrates that HA-based fillers provide substantial, measurable improvement in chin projection and high patient satisfaction. This reinforces the role of minimally invasive interventions in modern aesthetic practice while emphasizing the need for standardized outcome measures and long-term monitoring [18].

Table 3. Complications and Adverse Events

Table 3 provides a comprehensive summary of complications and adverse events reported in HA-based chin augmentation studies. Minor complications, such as swelling, bruising, edema, pain, and erythema, were common across all studies, affecting 20-30% of patients. These events were transient, typically resolving within 3-7 days, and were generally self-limiting or manageable with conservative measures such as ice application, analgesics, or temporary massage. This aligns with the expected safety profile of HA fillers, confirming that most side effects are mild and predictable [19].

Major complications were rare, reported in only two studies (Lee et al. and Rossi et al.) as nodule formation at rates of 1%. No serious vascular complications, such as skin necrosis or vision impairment, were observed in the majority of studies. The reported nodules were effectively treated with hyaluronidase injection, demonstrating the reversibility and manageability of complications associated with HA fillers [20-22].

It is important to note that complication rates may be influenced by injection technique, filler rheology, and practitioner experience. For example, bolus injections may increase local pressure, potentially raising the risk of vascular compromise or nodule formation if performed inappropriately. Linear threading with small volumes per injection appears to minimize these risks. Additionally, higher-cohesively HA fillers may provide more structural support but also increase firmness, which can occasionally lead to palpable irregularities.

Overall, the low incidence of major adverse events, combined with predictable minor reactions, highlights the favorable risk-benefit profile of HA-based chin augmentation. Clinicians should continue to adhere to established safety protocols, including knowledge of facial vascular anatomy, aseptic technique, and appropriate patient selection, to minimize the risk of complications. In conclusion, Table 3 emphasizes that while minor side effects are common, they are temporary and generally well-tolerated. Serious complications are extremely rare and manageable, reinforcing HA fillers as a safe and effective non-surgical alternative for chin enhancement [23].

Table 4. Filler Volume and Injection Technique

Table 4 details filler volume, injection points, technique, and retreatment rates. Mean total filler volumes ranged from 1.5 to 2.0 mL per patient, reflecting moderate augmentation suitable for mild-to-moderate chin retrusion. Injection points varied from 4 to 6, with linear threading and bolus techniques being the most commonly reported approaches [24].

Linear techniques, as used in Smith, Chen, and Rossi studies, distribute the filler along the mandibular contour, providing smooth projection and minimizing focal pressure. Bolus injections, employed in Lee and Patel studies, allow precise volumetric augmentation at key projection points but may increase local pressure and risk of asymmetry if overfilled. The choice of technique often depends on anatomical considerations, desired projection, and practitioner experience.

Overall, Table 4 illustrates that careful selection of injection technique and volume is critical for optimizing outcomes while minimizing complications. Understanding these technical parameters allows clinicians to tailor treatment plans for individual patient anatomy and aesthetic goals.

Table 5. Duration of Aesthetic Effect and Patient Satisfaction