Differences in the inflammatory response in young and old human subjects during the course of experimental gingivitis

The aim of the present experiment was to study changes in (i) the composition of the inflammatory cell infiltrates and (ii) levels of alpha 2-macroglobulin, lactoferrin and IgG subclasses in gingival crevicular fluid in young and old individuals during 3 weeks of plaque formation. To establish healthy gingival conditions, all subjects received professional tooth cleaning during a 4 week pre-experimental period. The experimental sites included the mesio-palatal, palatal, and disto-palatal surfaces of all teeth present in the 15...25 tooth region. At baseline (day 0) assessments of plaque and gingivitis, microbial sampling and gingival fluid assessment were performed and one gingival biopsy harvested from each subject. Following the baseline examination, the participants abolished mechanical tooth cleaning measures in the palatal and approximal surfaces of 15...25. The clinical examination and the gingival fluid measurement were repeated on days 7, 14 and 21 of no oral hygiene. The microbiological sampling and the biopsy procedure were repeated on days 7 and 21. The gingival crevicular fluid samples harvested from the old individuals had higher levels of alpha 2-macroglobulin and IgG3 compared to young subjects. The immunohistochemical analyses of the biopsies demonstrated that the gingival lesion representing the old individuals harbored a higher proportion of B-cells and a lower density of PMN cells compared to the infiltrate in the young group of subjects. It is suggested that differences exist in the inflammatory response to de novo plaque formation in young and old individuals.