This retrospective study evaluated the clinical outcomes of lithium disilicate prostheses on teeth and implants. A total of 860 restorations, including crowns, veneers, and onlays, were delivered to 312 patients. Patients with uncontrolled gingival inflammation and/or periodontitis were excluded, while patients with occlusal parafunctions were included. The retrospective observational period ranged between 13 and 17 years. The mechanical and esthetic performance of the restorations were rated according to the modified California Dental Association (CDA) criteria. The recorded data were analyzed statistically. In total, 26 mechanical complications were noticed: 17 ceramic chippings, 5 core fractures, and 4 losses of retention. Mechanical complications occurred predominantly in posterior areas; monolithic prostheses showed the lowest percentage of structural problems. The clinical scores of layered and monolithic restorations were fully satisfactory according to the modified CDA rating. The cumulative survival and success rates ranged from 95.46% to 100% and 93.75% to 100%, respectively, up to the 17-year follow-up. Although patient selection and the rigorous application of validated clinical protocols were considered paramount, the use of lithium disilicate prostheses on teeth and implants was reported to be a viable and reliable treatment option in the long term.