4.1. Subjects 
tooth
Thirty-eight subjects participated in this study. The main criteria for enrollment were that the patients had at least one tooth scheduled for extraction, all previous therapeutic options had been exhausted, and they had the possibility of dental implant placement at the extraction site after alveolar ridge augmentation. The criteria for inclusion were (1) age of subjects ≥18 and ≤60 years, (2) understanding of the protocol and informed consent signed by each subject, and (3) satisfactory physical and mental health of the subjects. Subjects who had some of the exclusion criteria were excluded from the study: (1) at least one absolute contraindication to implant therapy described by Wang and Hwang 2006. [