Restorative margin placement and periodontal health.

Subgingival restorative margins are associated with the development of plaque-related inflammatory periodontal disease, primarily because of a shift in the subgingival microflora from a profile associated with health to one associated with disease. The degree and extent of the marginal inflammation is influenced by four factors: failure to maintain proper emergence profile, inability to adequately finish and/or close subgingival margins, placement of subgingival margins in an area with minimum to no attached gingiva, and violation of the biologic width. Supragingival margin placement is the location of choice for all restorative margins to avoid iatrogenic periodontal disease. However, consideration of these four factors will help reduce the adverse impact of restorative margins that must be carried subgingivally.