Significance of the width of keratinized gingiva on the periodontal status of teeth with submarginal restorations.

The purpose of this clinical study was to evaluate the periodontal condition of teeth having submarginal restorations associated with either narrow or wide zones of keratinized gingiva. Fifty-eight teeth in 26 individuals were selected and then divided into two groups according to the width of the keratinized gingiva at the midfacial aspect of the tested tooth. Group I consisted of 30 teeth with greater than or equal to 2.0 mm, and Group II consisted of 28 teeth with less than 2.0 mm of keratinized gingiva. Each group was equally subdivided into subgroup "A" having teeth with a full coverage, subgingival type of restoration for at least 2 years, and subgroup "B" representing contralateral homologous teeth, in the same individual, with no subgingival restoration. Clinical examination of individual teeth included determination of plaque and gingival indices, gingival fluid, probing depth, bleeding tendency and bone level. Data were subjected to statistical analysis using the Student t test and a two-way analysis of variance to determine any significant differences in variables between teeth with and without subgingival restorations, in narrow and wide zones of keratinized gingiva. The findings were: (1) teeth with subgingival restorations and narrow zones of keratinized gingiva showed statistically significant higher gingival scores than teeth having submarginal restorations with wide zones of keratinized gingiva. (2) Teeth without subgingival restorations showed no statistical difference between narrow and wide zones of keratinized gingiva (P greater than 0.05).