Injectable filler is a special type of substance made for injections into connective tissues, such as skin, cartilage or even bone, for cosmetic or medical purposes. The most common application of injectable fillers is to change one's facial appearance, but they also are used to reduce symptoms of osteoarthritis, treat tendon or ligament injuries, support bone and gum regeneration, and for other medical applications. Injectable fillers can be in the form of hydrogel or gels made from pulverized grafts.
Injectable fillers have risen in popularity mostly due to the wide application of dermal fillers in 80's. Their premise is to help fill in facial wrinkles, provide facial volume, and augment facial features. Side effects include bruising or infections from improper sterilisation. This may include HIV infection, also allergic reactions, which may cause scarring and lumps. Blindness due to retrograde (opposite the direction of normal blood flow) embolization into the ophthalmic and retinal arteries can occur.
In 2012, "Artiste Assisted Injection System" was launched in the US market to assist in the delivery of dermal fillers. A study in 2013 concluded that the injecting device can achieve reductions in patient discomfort and adverse events by controlling the rate of flow of injection of the filler the practitioner is using to fill in the lips and frown lines.[5]
Soft-tissue augmentation has grown in popularity recently, particularly with the use of hyaluronic acid (HA) based dermal fillers. These non-permanent injectables can restore lost volume, smooth fine lines and wrinkles, and enhance facial contours. Despite their widespread use since the late 1990s, there is limited comparative data and literature on the diverse range of HA fillers and their tissue performance.
The studies explore various methods and parameters for characterizing dermal fillers, providing key insights for clinicians to select the most suitable products for their patients. The aging face undergoes complex changes due to bone resorption, gravity, fat redistribution, and skin damage, which dermal fillers aim to counteract. HA fillers are considered medical devices rather than medicines, thus lacking stringent regulatory requirements for safety and efficacy data.
The scientific community emphasizes the importance of understanding the physico-chemical properties of fillers, such as their behavior under stress and deformation, and their performance over time. These properties are influenced by different crosslinking technologies used in manufacturing.
A literature search identified key studies on the rheological properties of HA fillers, focusing on FDA-approved products and others like Revolax. The review analyzes methodologies and critiques the existing literature to provide a comprehensive understanding of HA fillers' properties
