Technologic advances in mechanics, electronics, physics, chemistry, and computer science have contributed to advances in dental medicine. Periodontology is not only a clinical science but is also directly related to the basic sciences. Research is conducted in laboratories rather than in clinics now. During the last century, aggressive periodontitis has received attention from numerous researchers because of its multifactorial features. This paper explores the long scientific journey of aggressive periodontitis, beginning with its first definition as alveolar diffuse atrophy. Perhaps in the future, "alveolar diffuse atrophy" will be referred to by another name or term. However, this journey will never end.