Objectives: To evaluate the clinical long-term success of prefabricated precision attachments in retaining uni- or bilateral removable dental prostheses. Method and Materials: Twenty-three patients with uni- or bilateral shortened dental arches received removable dental prostheses attached to the residual dentition with two types of precision attachments. Results: After 5 years, 70% of bilateral and 25% of unilateral removable dental prostheses remained clinically functional. The most frequent cause of clinical failure was fracture of the abutment teeth for bilateral partial dentures and irreversible wear of the precision attachment for unilateral prostheses. Oral hygiene status significantly improved, and the mean pocket depth of the abutment teeth did not increase after 5 years. Conclusion: Removable partial denture prostheses, retained bilaterally with precision attachments, are a reliable treatment modality without negative long-term effects on periodontal health, whereas unilateral removable dental prostheses cannot be recommended because of high clinical failure rates. Keywords: distal free end, precision attachment, removable dental prosthesis, unilateral