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Figure 1: Procedure protocol for injection of intradermal fillers for the treatment of facial aging. (i) The depth of needle insertion ranges from superficial
to mid-dermis and is dependent on both wrinkle type and filler type; (ii) release of intradermal fillers through the needle; (iii) filler insertion results in
smoothed wrinkles and the effect is long-lasting [31]
INTRODUCTION and non-permanent agents [e.g. bovine collagen, porcine
collagen, human collagen, hyaluronic acid (HA) and
A youthful face is characterized by fullness, balance, autologous fat]; (2) semi-permanent agents [e.g. poly methyl
smoothness, and the absence of facial lines or wrinkles. methacrylate (PMMA) microspheres, poly-L-lactic acid (PLA)
During the aging process, the outer shell of the human and calcium hydroxyapatite (CaHA)]; (3) permanent agents
body changes its appearance. These skin alterations are (e.g. silicone). The commercial products, their materials, and
often narrowly focused on facial wrinkles, one of the most their clinical efficacy are summarized in Table 1.
visible signs of the aging process. Therefore, the majority
of approaches intending to reverse skin-aging signs target Biodegradable and non-permanent fillers
[1]
the treatment of wrinkles. However, it has recently become Bovine collagen
more evident that the treatment of wrinkles alone is not Bovine collagen has been in use for over 20 years as
sufficient to restore a youthful facial appearance. As aging intradermal filler. It is extracted from bovine tendon, dermis
[3]
continues, the subcutaneous fat pads shrink, leading to the and bone. Once injected it has the ability to form a rigid
loss of structural support which in turn creates sagging of structure composed of fibrils, with an axial periodicity
the overlying skin. The loss of facial volume beneath the skin of native collagen which stays intact to help correct
[4]
(e.g. subcutaneous fat, muscle) is thus considered to be the facial defects. Since its approval by the Food and Drug
major contributor to the appearance of advanced age. [1] Administration (FDA) in 1981, highly purified bovine collagen
products have been used as fillers in more than 2 million
A number of minimally invasive dermatological techniques patients. Different forms of bovine collagen are currently
[5]
have been developed for facial rejuvenation. Injectable available, including Zyderm® I and II (Inamed Aesthetics,
dermal fillers can be injected through a needle into the Santa Barbara, CA, USA), composed of 3.5% or 6.5% bovine
upper layers of the dermis to treat superficial fine wrinkles dermal collagen suspended in a phosphate buffer solution,
or injected into the deep dermis or subcutaneous space for respectively. Both are used for the correction of superficial
facial volume augmentation [Figure 1]. Dermal fillers are lines including scars, peri-orbital lines and crows’s feet.
[2]
[6]
deposited in a slow and steady manner and fill central folds, Similarly, Zyplast® (Inamed Aesthetics), is composed of
resulting in a natural, long-lasting outcome. Crease depth, 3.5% collagen with the addition of 0.0075% glutaraldehyde,
desired outcome, and the patient’s financial situation are which helps to strengthen the collagen fibers and prolong
factors which need to be taken into account when deciding the duration of action. Zyplast® is primarily used to treat
[6]
the amount of product to be used. deeper scar tissue including acne scars and the vermillion
border of the lip.
[6]
This paper focuses on intradermal fillers, chosen due to
their ability to alleviate aging-related conditions and their Various distinctive studies have demonstrated the efficacy
ability to be easily incorporated into the armamentarium of Zyderm® in the cosmetic industry including a study
of outpatient cosmetic procedures with minimal overhead conducted by Nicolle, which showed the effectiveness
[7]
costs. of Zyderm® II in 350 patients treated for various facial
contour defects including acne, glabellar frown lines, peri-
TYPES OF INTRADERMAL FILLERS orbital lines and naso-labial folds. Eighty percent of the
patients treated were satisfied with their results although
Intradermal fillers can be roughly divided into three 5 patients showed signs of a positive localized reaction
[7]
categories depending on their durability: (1) biodegradable to the test dosage of Zyderm® II. Additionally, a clinical
Plast Aesthet Res || Vol 3 || Mar 23, 2016 73