# Assessment of Healing after Diode Laser Gingivectomy Prior to Prosthetic Procedures
## 1 Introduction  
The initial response after traditional instrument gingivectomy is the formation of a protective blood coagulum. The coagulum is then replaced by granulation tissue. At 24 h, the number of new connective tissue cells, mainly angioplasty, increases beneath the surface layer of inflamed and necrotic tissue. By the third day, many fibroblasts are located in the area. The highly vascularized granulation tissue grows coronally, creating a new free gingival margin and sulcus. The capillaries, formed by the blood cells in the periodontalligament, migrate into the granulation tissue and connect with the gingival blood vessels within 2 weeks [1]. After 12 to 24 h, epithelial cells at the edges of the wound begin to migrate onto the granulation tissue, separating it from the contaminated surface layer of the coagulum. Epithelial activity at the edges reaches its maximum at 24 to 36 h.  
New epithelial cells are formed by the basal and deep spinal layers of the epithelial ends of the wound, and migrate to the fibrinous layer of the wound, which is later resorbed and replaced by a bed of connective tissue. Epithelial cells bind to the substrate using hemidesmosomes and a new basal lamina [2]. In 5 to 14 days, the superficial epithelization is complete. During the first 4 weeks after gingivectomy, keratinization is weaker than before resection. Complete recovery of the epithelium takes approximately 1 month. Vasodilatation and vascularity begin to decrease after 4 days of recovery and are closest to normal on day 16. Full connective tissue recovery takes approximately 7 weeks [3]. The amount of crevicular fluid initially increases after gingivectomy and decreases with the onset of the healing process. The peak in the amount of crevicular fluid is after one week, which coincides with the peak in the inflammatory process [4]. Although tissue changes that occur in the healing process after gingivectomy are the same in all individuals, the time required for complete recovery varies considerably. It depends on the area of the incised tissue and the interaction with local inflammation and irritation. In patients with physiologically melanotic gingiva, pigmentation is reduced after gingival healing [5; 6; 7]. Laser gingivectomy is a contemporary alternative to traditional soft tissue surgery. The results from a clinical point of view are competitive and promising. When soft tissues are incised with a laser (with the correct choice of wavelength and settings), healing is referred to as 'calm'. The need for sutures or periodontal dressings is almost always avoided. Regardless of the wavelength, the healing after laser gingivectomy is per se-cundam intentionem (from Latin--'secondary', literally 'by secondary intention'); thus, it is impossible to superimpose exactly the shear edges as in their original appearance. It is important to note the phenomenon of the lack of bacterial contamination due to the bactericidal effect of the laser during the procedure [7; 8]. There is a protective layer of plasma coagulum and blood products--a strong surface film that allows for early healing in the underlying layers. Studies have shown that when longer wavelengths are used, there is no alignment of fibroblasts along the cut line, and there is a reduction in tissue shrinkage during healing. Such findings were also confirmed by clinical observations and are useful in determining the gingival margin level of a veneer or a crown [7]. The different laser operation modes significantly affect the desired laser-tissue interaction and heat relaxation. If the recommended operating techniques are not followed, charring occurs when the temperature exceeds 200 \({}^{\circ}\)C. Carbon absorbs all wavelengths, which leads to local heat accumulation and subsequent damage [9]. In short waves, heat is conducted and accumulated in the tissue, which leads to collateral unwanted changes, often in the form of edema.