Implant-prosthetic therapy requires detailed and precise planning to achieve optimal function, aesthetics, and naturalness of the future prosthetic replacement. Each therapy starts with anamnesis and clinical examination with the analysis of photographs, Cone Beam Computed Tomography, or orthopantomographic images. This is followed by the positioning of the implant in a precisely determined orofacial, mesiodistal, and apicocoronal dimension where it is crucial to maintain sufficient thickness of the buccal wall to achieve optimal levels of peri-implant mucosa. When treating patients, it is important to preoperatively examine risk factors, control of hyperglycemia, level of oral hygiene, width, and thickness of the keratinized peri-implant mucosa, thereby preventing certain conditions that can endanger the dental implant. The role of the attached gingiva in maintaining periodontal and peri-implant health has been extensively researched, but the evidence has been ambiguous. There is a general consensus that gingival augmentation around a dental implant should be performed in cases where the patient cannot maintain adequate plaque control, when there is soft tissue recession, and for pre-prosthetic purposes. The existing literature advocates for ≥2 mm width of keratinized tissue around the implant, as its presence is associated with reduced mucosal inflammation, discomfort during brushing, and the amount of plaque. Augmentation of the gingiva using a free gingival graft is the “gold standard” procedure for increasing the amount of keratinized tissue. The purpose of this paper is to present the application of the free gingival graft technique in surgical therapy for the deficiency of the attached gingiva in the lateral part of the mandible as a preparation for implant-prosthetic therapy for edentulism with a simultaneous surgical procedure of deepening the vestibule, and to present current recommendations in treatment through a review of recent literature on the subject.