<p>Collagen is a major constituent of the gingival extracellular matrix, which crucially affects the histoarchitecture of the gingival tissue. Collagen type I dominates the gingival tissue, while type II, III and IV are present to a lesser extent. Changes in distribution and density occur in the inflamed gingiva. The aim of the study was to examine the organization and density of the collagen in healthy and inflamed gingiva. The material for the study consisted of the gingival biopsies performed in 96 patients aged from 13 to 70 years. The gingival specimens were classified into 4 groups: healthy gingiva, gingivitis, moderate periodontal disease and severe periodontal disease. The samples of the gingival tissues were stained by the method of Van Gieson’s Stain, while the VD of the collagen was measured bz the use of multipurpose testing system M42. In healthy gingival collagen are thick and receptive to color. In gingivitis collagen is mostly preserved structure, but reduced volume; in the periodontitis collagen bundles are reduced, short, thin, disorganized, often fragmented and less susceptibility to color. In healthy gingiva collagen fibers occupy 58.6 ± 5.1% of the volume of lamina propria; in gingivitis significantly lower (44.2 ± 6.2%); in moderate periodontitis 32.7 ± 8.5% and in the progressed periodontitis only 28.7 ± 9.7%. Based on our results, we concluded that in periodontal disease occurs collagenolysis. Quantitative evaluation of gingival collagen volume density may reflect the clinical severity of periodontal disease.</p>