The aim of this case report was to describe a modified free gingival graft technique for gaining vertical and horizontal soft-tissue growth in the posterior region of the mandible before installation of dental implants. Patient A.A., a 38-year-old female, received a modified free gingival graft in the posterior region of the mandible. After 90 days, an increase, both horizontally and vertically, of the gingival tissue was observed, and the patient was satisfied with the result. The dental implant was installed, and a 3-mm of the vertical gain of keratinized gingiva was observed. Further research is needed to evaluate the effectiveness of this technique before prosthetic dental implantation.