It has been suggested that 1-2 mm of bone width at the buccal and lingual aspect is required for a successful long-term implant outcome. Low levels of evidence support this minimum threshold of bone width. This prospective study aimed at evaluating the outcome of implants placed in alveolar ridges with limited bucco-oral dimensions. One-hundred implants (dia. 3.5 mm) were placed in 28 patients with narrow alveolar ridge dimensions (<4.5 mm width) without augmentation procedures and conventionally loaded. Intra-oral radiographs were taken at implant placement and abutment connection and at 1, 2, 3, 5 and 10 years of follow-up. At the 10-year follow-up (21 patients; 75 implants), full-mouth periodontal charting was performed, and the peri-implant keratinized tissue width and attachment type were recorded. Two calibrated periodontists analysed the peri-implant bone changes. After 10 years, all implants showed successful osseointegration and a cumulative survival rate of 100%. The implants were placed 0.85 mm ± 0.89 mm subcrestally. After 10 years, the marginal bone was located 1.59 ± 2.11 mm apical to the implant shoulder. Throughout this period of follow-up, the mean annual marginal bone loss was 0.094 mm. Furthermore, 84% of implants in 72% of patients presented with bleeding on probing. After 10 years of functional loading, implants placed in alveolar ridges with limited bucco-oral dimensions (≤4.5 mm) exhibited only minimum marginal bone loss.