The biologic width is a crucial physiological barrier that maintains the integrity of periodontal and peri-implant tissues in dentistry. This chapter comprehensively discusses the anatomical structure, measurement techniques, etiological factors, clinical assessment methods, and treatment strategies related to biologic width. Emerging approaches such as digital guided surgery, platform-switching implant designs, and bioengineering-based innovations aim to preserve this vital structure. Furthermore, the role of biologic width in preventing complications like peri-implantitis is emphasized, with personalized treatment algorithms proposed. Future directions include long-term clinical studies and artificial intelligence-based risk modeling, which are expected to significantly influence clinical practices in this field.