Correlation between gingival fluid measurements and macroscopic and microscopic characteristics of gingival tissue

Thirty interdental sites in 30 subjects having varying degrees of periodontal inflammatory disease were evaluated. A G.I. score was recorded, crevicular fluid collected and measured, pocket depths measured and biopsies undertaken. Two histological indices were developed, one based on the extent of inflammatory cell infiltration and epithelial breakdown (H.I.) the other on the number of extravasated inflammatory cells (I.C.I.). Low positive correlations of about the same strength (r = 0.3) were found between both histological indices and the G. I. and fluid measurements. No correlation at all was found between the histological index and pocket depth, but there was a slight correlation between the inflammatory cell index and the depth of the pockets. A moderate correlation was found between the amount of gingival fluid and G.I. scores. A low degree of correlation was found when the G.I. was compared with pocket depths. The strongest relationship was between the Histological Index and the Inflammatory Cell Index. It seems probable that different indices evaluate different aspects of the inflammatory response. In studies of small samples it may be wise to incorporate parameters which evaluate both macroscopic and microscopic characteristics as well as measurement of gingival fluid whenever practicable. For incidence and prevalence studies, however, a gingival index based on macroscopic criteria and measurements of pockets and loss of attachment are much simpler and quicker than the collection, staining and measurement of gingival fluid, whilst histological examination is usually impracticable.