Relationship between crowns and the periodontium: a literature update.

Location of the crown margin, marginal fit, crown material, and crown contour all impact periodontal tissues. This literature review evaluated available data on their relationship with the periodontium and also examines whether any changes in established knowledge and/or perspectives have been published during the past 30 years. Electronic and manual searches conducted for in vivo investigations in the English and German literature for 1953 to 2009 provided 64 studies. Findings indicate that the supragingival location remains the most advantageous from the periodontal point of view; esthetic demands, however, dictated an intracrevicular location of the margin in the anterior zone. Metal-ceramic and all-ceramic crowns show a clinically acceptable marginal fit. Ceramic materials have the lowest plaque-retaining capacity, and a normal crown contour guarantees satisfactory periodontal health and esthetics. The accompanying data confirm the results reported in the literature, revealing that nothing has substantially changed, thereby supporting current approaches.