Non-ablative fractional laser: We described another similar study by Dr. Chia-Chen Wang et al. using a 1,550 nm, Er-glass fractional laser system with energy settings of 17 mJ and 169 MTZ/cm2, 2 passes (total density of 338 MTZ/cm2) for five sessions at 1-month intervals on rats. Their results showed this non-ablative fractional laser successfully removed white and flesh-colored cosmetic tattoos by trans-epidermal elimination of tattoo pigments through the disrupted dermal–epidermal junction.
Although CO2 ablative fractional resurfacing is theoretically more effective than non-ablative fractional laser, they found non-ablative fractional laser was as effective as CO2 ablative fractional resurfacing for cosmetic non-black colored tattoos.
Depressed acne scar
Ablative fractional laser: The most frequent use of fractional laser in Taiwan is for depressed acne scar. As we previously described, Dr. Sindy Hu et al. evaluated the effectiveness and safety of ablative fractional 2,940 nm Er-YAG laser for the treatment of atrophic facial acne scars in Taiwanese patients. With the setting of 100 to 150 μm, 5 to 20 mm2 scanning mold, 430 μm spot size, and 11% coverage density, they performed two passes of the laser on the cheeks and nose and one pass on the forehead. They also performed extra passes with level 2 to 3 in coagulation mode on the cheeks and level 1 on the forehead and mandible to create an extra thermal effect. They found nearly three-quarters of the patients with good to excellent improvement.
Non-ablative fractional laser: We described in our previous series about another similar study by Dr. Sindy Hu et al. evaluating the effectiveness and safety of a non-ablative 1,550 nm Er-Glass fiber laser in the atrophic facial acne scars. With one treatment session by Fraxel SR 750 (Reliant) at a setting of 15-20 mJ/MTZ (682-754 μm depth, 146-160 μm width/spot) and a density of 1,000-2,000 MTZ/cm2 (total average energy 1.55 kJ), 60% of the patients had good to excellent results after 1 month. Their results of using Fraxel SR 1,500 at a setting of 30-40 mJ/MTZ (980-1,120 μm depth, 180 -190 μm width/spot) and a density of 392-520 MTZ/cm2 (total average energy 1.9 kJ) were similar.
HELIOSⅡ/LOTUSⅡ/HYPERION – Manufacturer: LASEROPTEK(www.laseroptek.com)
Therefore, both ablative and non-ablative fractional lasers have similar good results for depressed acne scar, but more and more dermatologists use both ablative and non-ablative fractional lasers combined to achieve an even better result. There is still no report regarding which combination methods will benefit most patients with minimal downtime.
The clinical applications of fractional lasers are enormous. We believe that through the basic researches described above, we can soon use the fractional laser, ablative or non-ablative, clinically to facilitate cutaneous drug penetration, to regenerate hair, and to remove difficult cosmetic tattoos on our patients in the near future.
