Periodontal conditions in patients treated with dental bridges

The periodontal condition of 385 lingual abutment tooth areas with varying location of the retainer margins was compared with that of 385 contralateral tooth surfaces which were caries-free and devoid of fillings. The periodontal condition was assessed by recording the Plaque Index (Silness and Löe 1964), Gingival Index (Löe and Silness 1963) and by measuring pocket depth by the method of Glavind and Löe (1967). The location of the retainer margins was recorded according to the Margin Index (Silness 1970a). A supragingival position of the crown margins seemed to be the most favourable location, whereas retainer margins at and below the gingival crest interfered significantly with gingival health. The most harmful effects upon the gingival condition seemed to be produced by retainer margins located subgingivally.