Amalgam restorations, plaque removal and periodontal health

A total of 156 approximal subgingival amalgam overhanging margins were assessed in the buccal segments of 13 patients for plaque accumulation, gingival inflammation, pocket depth and gingival shrinkage. Recordings were made immediately before and 2, 4 and 8 weeks following scaling, removal of overhangs, and oral hygiene instruction. Surfaces with overhangs were compared with control surfaces, which were either intact or contained supragingival amalgams. Initially it was found that gingival inflammation and pocket depth were more extensive adjacent to subgingival amalgam overhangs than to sound teeth or those with supragingivally located amalgams. This appeared to be due to preferential plaque accumulation in relation to subgingival overhangs. For all parameters compared, differences apparent at the baseline had disappeared by the end of the 8-week study period. Contouring of defective subgingival restorations, followed by effective scaling and oral hygiene instruction produced approximately 1 mn of gingival shrinkage, sufficient in most cases to produce clinical gingival health. Of the 156 subgingival fillings 83 (53%) became supragingival and 43 (28%) reached the gingival crest by the end of the 8-week study period.