The efficacy of scar filler treatment varies significantly depending on the type of atrophic scar. Atrophic acne scars are generally classified into three main subtypes: rolling, boxcar, and icepick scars.

Among these, rolling scars, characterized by a gradual transition from normal skin to the scarred area and a wave-like surface morphology, are associated with the highest treatment success rates. With an adequate number of treatment sessions, near-complete flattening can be achieved in the majority of cases. However, the exact number of sessions required cannot be reliably predicted prior to treatment.

In contrast, boxcar scars, defined by well-demarcated, crater-like depressions with sharp borders, demonstrate a more heterogeneous response to treatment. While complete flattening may be achieved in certain subtypes, other cases show only partial improvement, and optimal aesthetic outcomes may not always be attainable. Additionally, a subset of boxcar scars exhibits minimal response to scar filler treatment.

Icepick scars, characterized by their narrow diameter and deep penetration resembling puncture marks, generally show the lowest treatment response. Although satisfactory outcomes may be achieved in a limited number of cases, the majority of patients demonstrate only minimal clinical improvement following scar filler treatment.

In conclusion, scar type is a key determinant of treatment success in scar filler procedures. Nevertheless, even within the same scar subtype, treatment outcomes may vary considerably depending on individual skin characteristics, scar depth, and patient-specific tissue response.