Introduction: The relationship between implant length and prosthetic crown height has traditionally been considered a critical factor in the biomechanical stability of implant-supported restorations. High crown-to-implant ratios (CIR) have been associated with increased stress at the bone–implant interface and potential risk of failure. However, recent evidence suggests that this parameter may have a limited clinical impact when other factors are properly controlled. The aim of this study was to retrospectively evaluate the clinical performance of extra-short, narrow-diameter implants placed in situations with crown-to-implant ratios ≥3. Materials and Methods: A retrospective study was conducted including patients treated in 2020 with extra-short implants (4.5–6.5 mm) and narrow diameters (3–3.5 mm), supporting single or fixed restorations. All cases had a minimum follow-up of five years. Treatment planning was performed using CBCT and digital software, allowing individualized surgical protocols to optimize primary stability. Clinical and radiographic follow-up included periodic periapical radiographs. Implant survival was assessed using Kaplan-Meier analysis, and marginal bone loss was measured using calibrated digital images. Results: Six patients with 24 implants were included, with a mean follow-up of 62.6 ± 7.8 months. The mean crown-to-implant ratio was 3.27 ± 0.26 (range 3–3.9). Implant survival was 100%, with no failures recorded. Prosthetic survival was also 100%, although seven minor technical complications were observed, mainly screw loosening. Mean marginal bone loss was 0.42 ± 0.59 mm (mesial) and 0.45 ± 0.70 mm (distal). Most implants were immediately loaded and restored with screw-retained prostheses. Conclusions: Extra-short, narrow-diameter implants placed in situations with crown-to-implant ratios ≥3 can achieve favorable medium-term clinical outcomes. Implant survival and marginal bone stability appear to depend more on biomechanical and biological factors than on the magnitude of the crown-to-implant ratio itself. These findings suggest that high CIR values should not be considered a limiting factor when appropriate treatment planning and load control are applied.