Change in diet and oral hygiene over an 8-week period: effects on oral health and oral biofilm.

The aim of the study was to monitor changes in oral health and oral biofilm composition in vivo during an experiment simulating prehistoric lifestyle and diet and poor oral hygiene. Thirteen subjects lived for a period of 8 weeks under Neolithic conditions. The following clinical parameters were recorded before and after the project: gingival and plaque index (Löe and Silness, Acta Odontol Scand 21:533, 1963; Silness and Löe, Acta Odontol Scand 22:121-135, 1964), probing pocket depth, and bleeding upon probing. In addition, supragingival plaque samples were collected both before and after the project and were analysed quantitatively using multiplex fluorescence in situ hybridization and confocal laser scanning microscopy. The following plaque bacteria were evaluated: Streptococcus spp., Veillonella spp., Fusobacterium nucleatum, and Actinomyces naeslundii. The plaque index increased significantly from 1.12 up to 1.55 over the 8-week period (gingival index before, 0.46; after, 0.93; p < 0.05). A strong correlation of both indices was recorded before (r = 0.77) and after (r = 0.83) participation in the study. Each of the children in the study showed a progression of carious lesions and/or new areas of demineralisation. The probing pocket depth and bleeding upon probing were not affected. All subjects yielded an intra-individual shift in biofilm composition. The proportion of F. nucleatum decreased across all subjects. The proportion of Veillonella spp. increased among the children. Poor oral hygiene and change of diet lead to an increase in oral plaque and gingival inflammation. The inter-individual comparison indicated a shift in bacterial composition.