Microbiology of early supragingival plaque development after delmopinol treatment

The aim of this double blind, cross-over, microbiological study was to compare the effect of topical application of the plaque control agent 0.5% delmopinol HCl with placebo on early supragingival plaque formation. Six subjects underwent 7 periods (0.5, 1, 2, 8 and 24 h and 3 and 7 days) of placebo and delmopinol application, respectively. At the start of each study period the teeth were professionally cleaned and 2 ml of placebo and delmopinol 0.5%, respectively, were applied on all teeth (twice daily for periods lasting 24 h or more). At the end of each period, supragingival plaque samples of one upper and one lower buccal tooth surface were collected separately and cultured on anaerobically incubated Brucella blood agar, on aerobically incubated blood agar and on selective media for the enumeration of Streptococcus spp., Haemophilus spp., Actinomyces spp., Veillonella spp., Neisseria spp. and Fusobacterium spp. The total anaerobic cultivable microflora after delmopinol use was 10-100 times lower than after placebo use. Compared with placebo, the proportion of cultivable aerobes (61.3%), Streptococcus spp. (104.8%) and Haemophilus spp. (82.3%) increased and the proportion of Actinomyces spp. (86.1%), Veillonella spp. (60.5%), Neisseria spp. (96.9%) and Fusobacterium spp. (60.6%) decreased after 7 days. Short-term application of 0.5% delmopinol HCl on supragingival dental plaque regrowth resulted in a reduction of the number of cultivable microorganisms in the plaque and produced a shift in the cultivable plaque composition.