The importance of gingival augmentation to increase the amount of keratinized tissue is a controversial subject. In this case report, an acellular dermal matrix was used to obtain an increase in the amount of keratinized tissue around four implants. In this case, the acellular dermal matrix was placed on bone. The surgical procedure resulted in an increase in the amount of keratinized tissue. Therefore, it met the clinical goals of the surgical procedure. However, the clinical findings and patient pain levels during the healing seemed to resemble a denudation procedure. Additionally, the histologic evaluation of the tissue that formed around the implants showed that the acellular dermal matrix was not incorporated into the result. Based on this case, the use of an acellular dermal matrix placed on bone does not seem to be a good technique to increase the amount of keratinized tissue.