This narrative review comprehensively evaluates the clinical applications and effectiveness of oral irrigators (water flossers) compared to traditional interdental aids in the management of periodontal and peri-implant diseases. Drawing from an extensive literature search across databases including PubMed, Embase, MEDLINE, and Google Scholar (1971–2025), the review covers historical evolution, current usage patterns, device classification, and future technological advancements in water flossing. Oral irrigators, which utilize pulsating and pressurized water streams, have demonstrated efficacy in plaque removal, reduction of gingival inflammation, and improved access to subgingival and interproximal areas—particularly beneficial for patients with implants, orthodontic appliances, or compromised manual dexterity. Clinical evidence indicates that water flossers are often superior or at least equivalent to dental floss and interdental brushes in reducing bleeding on probing, plaque indices, and inflammatory markers. Furthermore, their synergistic use with antimicrobial agents such as chlorhexidine enhances their therapeutic impact. While water flossers show promise in improving patient compliance and oral hygiene outcomes, certain limitations—such as the risk of transient bacteremia and microbial colonization—warrant further investigation. Innovations like app-controlled devices, biofeedback mechanisms, and AI-driven water flow adjustments represent the future of personalized oral hygiene. Overall, water flossers emerge as effective, patient-friendly tools with broad utility in modern dental care. Continued research and innovation will further solidify their role in promoting periodontal and peri-implant health.