4. Discussion In contrast to the usual omnidirectional type III collagen, scars are caused by a disorganized healing response that leaves behind fibrotic type I collagen. Collagen makes the wound stronger and makes it easier for macrophages and endothelial cells to move around it. When compared to healthy skin tissue, the ratio of collagen type I to type III is higher in mature scars. Older scars have fewer blood vessels and typically lack skin appendages such as sebaceous glands, sweat, and hair follicles. After an acute injury (such as surgery, a laceration, an abrasion, a burn, or a deep inflammatory skin disease such as acne), thickened raised scars develop due to excessive collagen synthesis (fibrosis). Through a real microablation, a CO2 laser with a fractional scanning system (SCAR3 scanner) generates micro columns of thermal damage surrounded by healthy tissue that can cause the vertical scaling of the epidermis; these microthermal zones (MTZs) found around the ablation zones encourage a new and rearranged collagen pattern that is crucial to the neocollagenesis process.

The skin around each column does not suffer thermal damage (ablation and coagulation), but only a biostimulation effect and evaluation of the distance between each single DOT is fundamental to achieving the fastest healing process and the best clinical result. Collagen stimulation and the cutaneous rejuvenation effect depend on the depth of thermal damage at the level of the dermis that triggers the formation of new collagen and tissue repair [16].

Additionally, if this is coupled with the SCAR3 scanning system’s ability to achieve a deeper level of action (owing to its tiny spot size) and a more noticeable bleeding and crusting process than a traditional scanner, an exceptional outcome is undoubtedly reached [13]. An increase in the coagulation area caused a greater shrinkage of the tissue but still fell within a range that did not affect the tissue healing. This innovative laser system enhanced its effects, both in terms of tone thanks to a greater tensor effect, and of stimulation because of a greater volumetric thermal effect. This greater shrinkage effect on the ex vivo skin model was already demonstrated in the study of Nisticò et al. [17].

The new scanner having smaller spot sizes may be optimal for rapid epidermal wound healing by minimizing the keratinocyte migration path or period. The fractional approach combined with an optimal treatment coverage or spot density and pulse energy may allow for a favourable ratio of viability to the treated tissue.

Deep scars require more ablation and therefore also more energy. The most severe scars require lasers with a depth of action >1 mm, and this can be achieved by increasing the ablative power, which is related to the energy delivered from the system [18]. Since an increase in the depth of the action is directly related to the energy supplied, this consequently increases the risk of inflammation. This is why it was necessary to reduce the spot size of the DOT (columns of thermal harm). From this perspective, the new scanner SCAR3 was developed to obtain greater depths of ablation and, at the same time, reduce the amount of energy delivered to limit patient pain and the risk of occurrence of PIH.

The CO2 laser system, with the use of the new SCAR3 scanning system and conservative parameters, reaches the deep layers of the dermis up to a depth of >1 mm. This implies that the potential effect of this laser, at the chosen parameters, covers all skin targets necessary to carry out superficial or deep treatments for any dermatological problem. Indeed, many scar areas are more than 1 mm thick and extend more than several millimetres in depth. To effectively treat these lesions, a laser ablation penetration depth greater than 1 mm is required, going as deep as possible to initiate the healing cascade and achieve good results in scar remodelling [13].

In addition to guiding patient selection, the type of injury and the variation in penetration depths caused by ablative and thermal injuries of our study device also determine the type of skin scars to be treated, how many passes are made during a single treatment period, and whether additional treatments are necessary. The deep layers of the dermis can be penetrated by the CO2 laser system throughout the entire dermal thickness when using the new SCAR3 scanning system; this suggests that this laser’s potential impact, at the selected settings, covers all skin targets required to perform superficial or deep treatments on any dermatological issue. Many scar areas extend more than several millimetres deep, and so to start the healing cascade and achieve effective results in scar remodelling, a laser ablation penetration depth is necessary [13].

More significantly, this novel scanning technology enhances treatment effectiveness while also decreasing patient downtime and associated recuperation periods [13].

Our histological findings confirm that the SCAR3 scanner enabled us to treat a wide variety of skin lesions because it can penetrate skin lesions up to a depth of 5954 m, as is evident in Figure 1.

Patients who have problems such as deep morbid scar complications, affecting their quality of life, could benefit from this innovative technique. Our system may be applied clinically in many pathologies as it is possible to adjust the depth of action based on the energy delivered up to reaching depth values capable of treating different skin scars such as deep and conspicuous skin lesions/conditions. Therefore, expanding the plan and the findings of the study is our long-term objective.

5. Conclusions

The study’s findings confirm the Maximum Thermal/Ablation Lesion Depths achieved with the SCAR3 scanner and its dependence on energy delivered by the laser system. These findings will enable us to expand the clinical applications of the research tool to a variety of skin lesions.

Author Contributions: Conceptualization, P.B., T.Z., C.C. and D.P.; methodology, P.B., L.P., T.Z., C.C. and D.P.; software, P.B., L.P., T.Z., C.C. and D.P.; validation, P.B., L.P., I.F., F.M., T.Z., C.C. and D.P.; formal analysis, P.B., L.P., T.Z., C.C. and D.P.; investigation, P.B., L.P., T.Z., C.C. and D.P.; resources, P.B., L.P., T.Z., C.C. and D.P.; data curation, P.B., L.P., F.M., T.Z., C.C. and D.P.; writing—original draft preparation, L.P., I.F., F.M. and T.Z.; writing—review and editing, P.B., L.P., I.F., F.M., T.Z., C.C. and D.P.; visualization, P.B., L.P., I.F., F.M., T.Z., C.C. and D.P.; supervision, P.B., L.P., I.F., F.M., T.Z., C.C. and D.P.; project administration, P.B., T.Z., C.C. and D.P.; funding acquisition, P.B., T.Z., C.C. and D.P. All authors have read and agreed to the published version of the manuscript.