Purpose: To investigate the cumulative survival rate (CSR) and marginal bone loss (MBL) of single implants immediately placed and restored with two-unit cantilevered fixed dental prostheses (FDPs) following the extraction of two adjacent mandibular incisors with a compromised periodontal condition. Materials and Methods: Patients in need of extraction and replacement of two adjacent mandibular incisors due to an advanced periodontal loss of attachment were treated consecutively. Following a flapless procedure, a single implant was placed at the time of extraction in one of the two fresh alveolar sockets and immediately restored with a screw-retained two-unit provisional FDP. The area of extraction was grafted using xenograft particulate material. The following elements were evaluated: the peri-implant soft and hard tissue condition at the last follow-up appointment, MBL at the last follow-up appointment at least 1 year after the delivery of the final prosthesis, and the final esthetic result. Results: A total of 20 patients were recruited between January 2014 and December 2019 in a single private practice. Each of them received a single implant and immediate provisional restoration with a two-unit cantilevered FDP. Patients were followed up for 22 to 94 months (average follow-up = 4 years) and none of the implants failed, resulting in a 100% CSR. The cumulative MBL—measured using the VixWin Platinum software— was 1.08 ± 0.35 mm. A lower MBL was observed in the presence of platform switching (0.63 ± 0.11 mm) compared to the absence of platform switching (1.27 ± 0.20 mm). Conclusions: The preliminary results obtained from this study suggest that patients who need to replace two adjacent periodontally compromised mandibular incisors can be treated with an immediately placed and restored single implant.