Lower Face Contouring: 4 Areas of Injectable Fillers Techniques
The lower third of the face is significant in achieving a pleasant appearance, beauty, and youth. A well-contoured jawline is desirable in both men and women as it defines masculine and feminine characteristics. Non-surgical rejuvenation using injectable fillers is becoming more common to improve the appearance of this area by reshaping the jawline, lifting soft tissues, and enhancing facial proportions.
A proper aesthetic treatment plan requires a thorough understanding of facial anatomy and the aging process, as well as a comprehensive facial assessment. The aging process in the lower face involves resorption of the mandible, loss of fat compartments, and skin atrophy, resulting in a loss of jawline definition and formation of jowls. The rejuvenation approach aims to redefine the mandibular angle and line.
In this blog, the anatomy of the lower third of the face, facial assessment, aging process, and treatments using injectable fillers for the chin, prejowls, and mandibular line and angle, will be discussed.
Facial Assessment
When performing a global facial evaluation, it is essential to assess the shape, balance, and symmetry of the face. For midface volume correction, it is recommended to be done before lower face treatments to reposition and lift the soft tissue upward. However, since patients may not always recognize their lower face deficiencies, evaluating the lower third is important when treating the midface to optimize facial proportions.
The patient should be assessed in different positions, including rest and animation, with photographs taken from various angles. Careful examination involves palpation and assessment of the teeth to identify any orthognathic and odontological issues that may affect the treatment.
Aesthetic treatment planning should consider the patient's complaints and set realistic expectations. Ideal indications for lower face treatment are mild to moderate loss of facial contour and volume, including patients with inherent deficiencies in this region. It can also be beneficial for enhancing masculine characteristics in male patients or strengthening the lower third in female patients with oval or heart-shaped faces.
Facial Anatomy
Bone
The mandible is the primary structural component of the lower face, consisting of an inferior horseshoe-shaped portion and two perpendicular parts known as the mandibular ramus. The mandibular line refers to the area of the mandible from the mentum (chin) to the angle of the mandible.
Soft tissues
The skin on the face is thinner in posterior areas and becomes thicker as it moves anteriorly towards the chin. There are four fat compartments in the mandibular region, including superior and inferior mandibular fat pads, a submandibular fat compartment, and one covering the parotid-masseteric fascia.
In the lower third of the face, the layers differ in arrangement anterior and posterior to the labiomandibular sulcus. Posterior to the sulcus, the layers from superficial to deep include skin, superficial subcutaneous fat, platysma, deep fat, parotideomasseteric fascia, masseter muscle, and periosteum of the mandible. Anterior to the sulcus, the layers from superficial to deep include skin, subcutaneous fat, muscles of facial expression (depressor anguli oris, platysma, depressor labia inferioris, and mentalis), deep labiomandibular fat and deep mental fat in the chin, and periosteum.
The mandibular ligament is located in the inferior margin of the labiomandibular sulcus, anterior to the jowls, contributing to the formation of the jowl deformity. The aging process involves different arrangements of subcutaneous tissue around the labiomandibular sulcus, with loose adhesion laterally and tight adhesion medially.
Vasculature and Nerves
When performing filler injections in the lower face, it is crucial to be familiar with the location and depth of the facial artery, facial vein, and facial nerve to avoid potential complications.
The facial artery, a branch of the external carotid artery, crosses the inferior border of the mandible, anterior to the masseter insertion, along with the facial vein. It is essential to know their course, as they are located in deep fat beneath the platysma. The facial artery supplies blood to the face, branching into superior and inferior labial arteries near the modiolus and continuing as the angular artery as it ascends in the nasolabial sulcus region.
The primary blood supply to the chin comes from the mental arteries, which exit the mental foramen on the lateral chin, in line with the vertical axis of the second inferior premolar teeth, and midway between the lower and upper mandibular borders. The inferior labial artery and labiomental artery also contribute to the blood supply in the region.
The mental nerve, a branch of the trigeminal nerve, exits the mental foramen and provides sensory innervation, making injections in the chin and prejowl area potentially painful. Motor innervation in the area is given by the branches of the facial nerve, specifically the buccal and marginal mandibular nerves. The branches of the marginal mandibular nerve can be located above the mandibular border anterior to the masseter and 1 to 2 cm below the inferior mandibular border posterior to the anterior masseter border.
Parotid Gland
The parotid gland is positioned in the preauricular area, above the posterior region of the masseter muscle. The parotid duct originates in the anterior part of the gland and typically runs between the masseter and the parotideo-masseteric fascia, often found along an imaginary line from the earlobe to the oral commissure.
Treatment of the Lower Face
Lower third treatment with fillers can improve the jawline's shape and facial contour while providing a lifting effect for the cheeks and neck. Injectable fillers allow for three-dimensional augmentation of the chin in horizontal, vertical, and transverse dimensions. To achieve better structural improvements, higher elasticity products are preferred, while softer gels may be used in more dynamic areas or when the skin is thin.
The AB face technique, based on the anatomy of beauty, involves two steps: AB structure to enhance facial contours and proportions, and AB refinement to blend and smooth treated areas and correct remaining sulcus and grooves. The recommended products for reshaping the lower face are high-elasticity, hyaluronic acid-based fillers, often using a composite matrix gel with hyaluronic acid and calcium hydroxylapatite.
The treatment of different areas along the jawline is tailored to each patient's needs and priorities, considering the jawline as an aesthetic unit.
See below the figure for an illustration of the AB face technique, (a) showing the marking of the areas to be injected, (b) showing the areas where filler was injected, (c) and (d) showing before and after the treatment (From Braz et al, 2020)
1. Treatment of the Chin
The width of the chin is determined differently in women and men, using the medial intercanthal distance in women and mouth width in men as anatomical references. For ideal projection, men's chins should project to the level of the lower lip, while women's lower lips should extend 1 to 2 mm beyond the chin.
To enhance chin projection, fillers are mainly placed in the anterior portion (pogonion), while to augment its length, fillers are placed inferiorly in the menton area. The procedure involves marking a semicircle in the chin area respecting the ideal width for men or women, using an imaginary vertical line between the mentalis muscles for symmetry evaluation. A rectangular area is marked for filling, and the cannula entry point is lateral to the area of treatment, in the prejowl region, about 5 mm above the mandibular line.
Approximately 0.2 to 0.5 mL of filler is used on each side in the rectangular area, based on the patient's needs and treatment objective. Additional injections may be performed in a more superficial plane (subcutaneous) to smoothen the area, using approximately 0.1 mL per side. After cannula withdrawal, the area is shaped with precise and firm finger movements.
2. Treatment of the Prejowl Region
To restore the jawline, it is crucial to fill the depressed area medial to the jowl. However, caution should be taken to avoid overfilling, especially in women, as it can give the impression of a wider chin. The procedure involves marking a rectangular area using the medial limit (labiomandibular sulcus or medial border of the jowl) as the lateral border, the mandibular border as the inferior limit, and an extension of the horizontal superior line drawn for the chin treatment (1.5 cm above the mandibular border) as the superior limit.
The cannula entry point is positioned laterally to the prejowl, at a mid-distance between the two horizontal lines. The technique involves retroinjection in both submuscular and superficial subcutaneous planes within the marked rectangular area.
3. Treatment of the Mandibular Line
The jowl area, characterized by ptosis and excess volume, should not be treated. The area for treatment is located posterior to the jowl, extending until the mandibular angle, and it should be marked with two horizontal parallel lines—one along the mandibular inferior border and the other 1.5 to 2 cm above it.
For the procedure, the cannula entry point can be the same one used for filling the prejowl area in the jowl region. The product is injected in the superficial subcutaneous plane using retrograde injection.
This approach aims to correct the depression in the anterior border of the mandible caused by the premasseteric ligament and muscle volume. After injection, the area can be shaped with moderate pressure using fingers.
4. Treatment of the Mandibular Angle and Ramus
To treat the mandibular angle area, first, locate the mandibular angle through palpation. Then, draw a vertical rectangular area over the mandibular ramus, in the preauricular region and the inferior zygomatic lateral area, using two vertical lines approximately 3 cm apart with a 2 cm distance between them.
The cannula entry point is at the mandibular angle, and the product is injected in the subcutaneous plane using a retrograde injection technique. After the injection, the product is pressed onto the mandibular bone using the second finger to shape the treated area.
See below the figure for an approach to enhance the mandibular contour in a young woman, (a) shows the areas for treatment, (b) and (c) shows a before and after of treatment. (From Braz et al, 2020)
Conclusion
The shape of the jawline, specifically from the mandibular angle to the chin, significantly impacts an individual's appearance. Injectable fillers offer a safe and effective nonsurgical method to reshape this area and achieve aesthetic rejuvenation goals. Even in younger patients, facial beautification is possible by correcting deficits such as a small or recessed chin and enhancing facial contours. Understanding the anatomy of beauty, including facial anatomy and the aging process, is crucial for performing proper facial assessments and creating personalized aesthetic treatment plans for each patient.
Reference:
Using injectable fillers for chin and jawline rejuvenation (2023)
Nonsurgical Reshaping of the Lower Jaw With Hyaluronic Acid Fillers: A Retrospective Case Series (2022)
Reshaping the Lower Face Using Injectable Fillers (2020)
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