Morphometric analysis of collagen and elastic fibers in normal skin and gingiva in relation to age

The morphometric parameters of the human gingival elastic fiber network were determined by image analysis and compared with human skin elastic fibers in relation to age. Similarly, collagen fibers were also investigated in both tissues. In this study, 47 healthy patients, 10-75 years old were studied for gingiva and another 50 patients in the same age range were included for skin biopsies. Three groups were compared: group 1 from the age of 10-24 years, group 2 from 25 to 49 years, and group 3 from 50 to 75 years. The diameters of the oxytalan fibers were invariable in both tissues, whatever the age considered. On the other hand, the diameters of elastic fibers increased regularly with age in the gingiva (P < 0.01) and in the skin (P < 0.01) between each age group. The area fraction occupied by the oxytalan fibers decreased significantly in both tissues (P < 0.01) for the skin and (P < 0.001) for the gingiva. The area fraction occupied by the gingival elastic fibers remained constant with age while the skin elastic fibers increased significantly with age between groups 2 and 1 (P < 0.01) and between groups 3 and 2 (P < 0.001). In the mid-dermis and in the mid-gingiva, the diameters of the collagen fibers increased strongly with age, between groups 2 and 1 (P < 0.01) and between groups 3 and 2 (P < 0.001). The area fraction occupied by the collagen bundles increased regularly with age in the mid-gingival (P < 0.05 between each age group), while a significant decrease was observed in the mid-dermis from the age of 50-75 years (P < 0.05). The results obtained contribute to a better understanding of some modifications which dermis and gingiva undergo with aging and provide data to perfect diagnosis and therapy in odontology and dermatology.