Narrow-diameter implants (NDIs) are an important treatment option for patients with severe alveolar ridge resorption to repair missing teeth using implants with a diameter of ≤ 3 mm. Among them, the NDI-supported crown restoration design can effectively distribute occlusal force, while the overdenture ball attachment system shows excellent biomechanical adaptability in the fixed restoration of edentulous patients. Moreover, there are differences in materials of different NDIs. For example, titaniumzirconium alloy (Ti-Zr) has become the mainstream due to its 40% higher mechanical strength than pure titanium. Meanwhile, highly transparent zirconia, which combines aesthetics and strength through phase transformation toughening technology, is widely used in single crown restoration in aesthetic area. However, NDIs still face problems such as biomechanical risks and insufficient evidence of long-term success rate. Based on this, this article summarizes the restoration methods, materials and properties of NDIs, and reviews the digital application of NDIs, aiming to provide evidence-based basis for clinical practice.