This review is based on an extensive study of the literature, various investigations of clinical and dental materials, experience as well as long-term observations. Our understanding of the behavior of the gingiva at the margins of artificial crowns has been widely extended within the last two decades. Some of these findings are discussed. However, complete absence of inflammation at the gingival margins can hardly ever be expected. What is usually present is rather "an acceptable state of marginal periodontitis" (Ketterl). Continuous and deliberate oral hygiene on the part of the patients is a decisive prerequisite for an acceptable oral condition.