For multiple and large-area acne or smallpox scars, dermabrasion is the only technique for effective and rapid improvement. This technique is based on the mechanical planing of the skin, which enables depressed scars of different depths or sizes to gradually regenerate within a short recovery period and become smooth; therefore, it is also called mechanical dermabrasion. A high-speed diamond burr repeatedly abrades the epidermis and dermis at the whole scar area to level the scar edges and central depression. This process injures the skin and causes it to become red and secrete tissue fluids. In approximately 1 week, dermal cells start to grow and astringe the wound and scar. In the following 1-2 months, the defects of dermabrasion are filled with regenerated skin cells, which ultimately restore the original skin tone and smooth scars. Despite a long recovery period, this technique presents significant results, and each dermabrasion can treat 50% of depressed scars on average. If the patient has severe scar problems, 3 surgeries, at most, are needed to render 70–80% skin smoothness. Therefore, it is still accepted by numerous patients with severe facial depressed spots or orange peel-like skin, and it is also the only feasible treatment method.
The depth of dermabrasion is closely associated with the results and recovery speed, so dermabrasion at different depths is employed based on the severity of the patient’s scar. Superficial dermabrasion is limited at the epidermis and is mainly indicated for patients with sporadic or shallow depressed acne scars and is also used to abrade the stratum corneum to shrink skin pores and make the skin delicate. Its advantage is the rapid astringing of wounds (approximately 3–5 days) and a short recovery period (approximately within 1 month), but the disadvantage is the more courses of dermabrasion. Deep dermabrasion reaches the epidermis and dermis and is used for the treatment of depressed acne scars, smallpox scars, or facial orange peel-like skin. The advantage is the rapid and obvious results and fewer courses of dermabrasion, but the disadvantage is the relatively slow wound healing and a long recovery period (approximately 1–2 months), which is likelier to cause pigmentation and other sequelae. Therefore, patients still need advice from physicians before deciding on a surgical method.
Besides surgical dermabrasion, numerous non-surgical techniques are optional, such as dermabrasion (vaporization) laser, Fraxel, alpha-hydroxy acids, and micro-needle therapy system, for treating depressed acne scars, whose results and cost effectiveness are less obvious than those of dermabrasion. Therefore, if patients accept relatively long recovery periods, mechanical dermabrasion remains the preferred method to treat large-area acne scars.