The in vivo dynamics of Streptococcus spp., Actinomyces naeslundii, Fusobacterium nucleatum and Veillonella spp. in dental plaque biofilm as analysed by five-colour multiplex fluorescence in situ hybridization

Abstract

The in vivo dynamics of Streptococcus spp., Actinomyces naeslundii, Fusobacterium nucleatum and Veillonella spp. in dental plaque biofilm as analysed by five-colour multiplex fluorescence in situ hybridizationAli Al-Ahmad, 1 The formation and composition of dental plaque biofilm in vivo are important factors which influence the development of gingivitis, caries and periodontitis. Studying dental plaque biofilm in in vitro models can cause an oversimplification of the real conditions in the oral cavity. In this study, bovine enamel slabs were fixed in an individual acrylic appliance in situ to quantify dental plaque formation and composition using multiplex fluorescence in situ hybridization (FISH) and confocal laser scanning microscopy. Each of the five oligonucleotide probes used for FISH was specific for either eubacteria or one of four frequently isolated bacterial constituents belonging to early and late colonizers of tooth surfaces. The thickness of formed biofilm increased from 14.9±5.0 mm after 1 day to 49.3±11.6 mm after 7 days. Streptococcus spp. were predominant in 1-day-old dental plaque and decreased significantly after 7 days (P50.0061). Compared to the first day, Fusobacterium nucleatum decreased after 2 days and increased significantly after 7 days (P50.0006). The decreases of Actinomyces naeslundii content on day 2 and day 7 were significant (P50.0028). Changes in Veillonella spp. were not significant during the study period (P .0.05). The results showed that an in vivo observation period of 7 days was required to detect significant changes in Streptococcus spp. and F. nucleatum. The multiplex FISH used is suitable for analysing the dynamics of four important bacterial constituents in the oral biofilm in epidemiological studies. INTRODUCTIONDental plaque is the trigger for most dental diseases such as gingivitis, caries and periodontitis. Knowledge about the composition of dental plaque biofilm in vivo can be helpful in finding treatment and prevention strategies. Dental plaque consists of a multispecies biofilm of more than 500 species of bacteria and is the result of complex processes in the oral cavity (Foster & Kolenbrander, 2004;Kolenbrander et al., 2002;Kroes et al., 1999;Moore & Moore, 1994;Paster et al., 2001). Coaggregation consisting of cell-cell recognition between genetically distinct bacteria and coadhesion due to the recognition between planktonic cells and surface-attached cells are two important processes in biofilm development in the oral cavity (Bos et al., 1996;Ciardi et al., 1987;Gibbons & Nygaard, 1970;Kolenbrander et al., 2002). The interactions between bacteria and salivary proteins as well as with the extracellular matrix are also major elements in the development of plaque biofilms. Additionally, one important factor for the initial colonization during the formation of the dental plaque biofilm is the salivary acquired pellicle, which is the basis for further bacterial adhesion and colonization of the tooth surface (Lendenmann et al., 2000). The composition of the saliv...

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Temporal dynamics of bacterial microbiota in the human oral cavity determined using an in situ model of dental biofilms

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