generally inject into the superficial stratum for fine lines and wrinkles, particularly for patients with thin skin. For more broadly based wrinkles in normal skin, we generally inject dermal filler into the superficial and/or mid dermis. For deep wrinkles, for folds, and for patients with thick skin, we generally inject into the mid and/or deep dermis.
Hypodermis
This level, also referred to as the subcutis, is a fat layer under the 3 previous layers. Its thickness may reach several centimeters, depending on age, muscle tone, and adiposity of the individual.
Angle and Depth of Penetration
As clinicians, we have been taught (and, in turn, taught others) that injection into the superficial section of the reticular
dermis needs to be at an angle of penetration of approximately
30°. For injection into the mid and deep sections in the reticular dermis, the angle needs to be around 45°. In this article,
investigators reports data from multiple experiments and fact-finding projects to explore two questions: 1) Is it possible to inject into the superficial and mid-reticular dermis? and 2) Are the 30° and 45° angles the appropriate angles for penetration
into these layers?
Materials and Mathematical Calculations
Materials
Hyaluronic acid (HA) gel fillers
For all the studies and the real live treatments, three HA gel fillers were injected: Restylane® [(RES), Q-Med-Galderma (Uppsala, Sweden)]; Juvéderm® [(JUV) Ultra 3/Juvederm® Ultra XC,
