Key things to know about dermal fillers

By Dr. Aaron Stanes

Treatment guide

Discover the vital information you MUST know about dermal fillers with our detailed guide written by expert cosmetic doctors.


    Dermal fillers are volumising gels that can be used to restore lost volume, add volume in areas of natural deficiency and reshape facial features.

    Dermal fillers are temporary and reversible. Longevity is said to be between 6 and 18 months depending on the product type and personal biological characteristics that cannot be predicted or controlled. Despite this, it is generally accepted that the longevity of fillers is unpredictable. Rarely, they may be metabolised by the body in only a few months. More frequently, fillers are seen to last many years (as evidenced by MRI studies of the face performed years after dermal filler injection).

    Dermal filler considerations

    Longevity is an important consideration when deciding whether or not to undergo dermal filler treatment. it is critical to appreciate that filler longevity cannot be guaranteed, and you must make your decision based on the probability of longevity. Many people who claim that filler doesn’t last on them fail to appreciate the following considerations:

    • A lack of visible effect does not mean that the filler has worn off.
    • Initial swelling may give the appearance of a more pronounced result, that once settled leaves you feeling underwhelmed.
    • People are often quick to forget how they appeared before treatment.
    • Fillers can migrate to other areas of the face (generally when higher volumes are used more frequently).
    • People age over the top of their fillers.

    Dermal fillers can be immediately reversed by injecting a dissolving enzyme. Reversing dermal filler is generally done in cases where a complication has occurred, or if the results are not satisfactory, or when they are no longer desired. Reversing dermal filler is safe, but can cause bruising and swelling. There is also a rare risk of severe allergic reactions, and new anecdotal evidence suggesting that it may cause chronic pain and skin damage. Accordingly, reversing dermal filler should only be performed when absolutely necessary.

    Types of dermal fillers

    There are many types of HA dermal fillers available. They differ in specific rheological and other properties. Each type of HA filler has its own unique combination of properties that should be taken into account when selecting that particular HA gel for use. The key properties of HA dermal fillers are:

    • Cross-linking: how entangled the gel particles are.
    • Hygroscopicity: how much water volume the gel can hold.
    • Monophasic or biphasic: whether all filler particles are the same or there are two different forms in the one gel.
    • Filler concentration: how many milligrams of hyaluronic acid is contained in the gel.
    • Viscoelasticity (G’ or G-prime): how resistant the gel is to a change in its shape, and its tendency to spring back to its original shape after any force or pressure applied to it has been removed.
    • Cohesivity: the degree at which the gel will tend to stick together and not break apart, and is related to cross-linking.

    Longevity and thickness are not true measures of dermal filler, and should not be used when considering which type of HA gel is appropriate for a treatment. using a gel based on these properties can lead to the injection of the wrong gel for the treatment goal, increasing the risk of lumps that need to be dissolved.

    Dermal filler risks

    HA dermal filelrs are very safe, owing in part due to their reversibility. Risks of dermal filler injections include:

    • Bruising
    • Swelling
    • Redness and local tenderness
    • Mild and temporary headaches
    • Infections
    • Nodules
    • Foreign body reactions including granuloma
    • Allergic reactions
    • Over or under correction
    • Asymmetry
    • Lumps
    • Loss of vision (extremely rare)
    • Stroke (extremely rare)
    • Skin ischaemia and necrosis

    Different areas of the face have different risk profiles regarding the likelihood of a complication. The best way to minimise a risk of by having treatment at an experienced, doctor-led cosmetic clinic. It is not possible to fully eliminate procedural risks, and so you must accept them before proceeding with any treatment.

    Dermal filler volumes

    Dermal fillers typically come in a 1ml syringe, although some types come with slightly more or less. The total quantity of dermal filler is not as important as the type and application of the dermal filler. It is always preferable to use smaller quantities and build up your result over time. Overfilling an area not only causes a bad result, but may ned to be reversed. Certain areas of the face can only fit a limited amount of dermal filler before the procedure risk increases and damage to the tissue can occur. Over-filling can also increase the risk of dermal filler migration due to the elastic properties of the facial tissues. Lip filler migration is the most common problem due to overfilling.

    A guide to dermal filler volumes per session

    Just because you need more volume to achieve your goals does not mean it can or should all be injected in one session. Treatments are best staged over multiple sessions to reduce the risk and increase the precision.

    Dermal fillers

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