A comparative study of oral microbiocenosis structure in experimental comorbidity-free periodontitis and in...

Thyroid hormones regulate numerous metabolic processes. Therefore, any alteration in their synthesis or function has important health implications. However, limited data are available regarding the relationship between thyroid hormone imbalance and periodontal health.

The aim of the study was to perform a comparative analysis of qualitative and quantitative structure of oral microbiocenosis in rats with comorbidity-free periodontitis and in animals with periodontitis in a setting of hyper- and hypothyroidism.

Inbred white male rats (n=48) were randomly divided into the following groups: I - control animals, II - animals with a model of periodontitis, III - rats with periodontitis in a setting of hyperthyroidism, IV - rats with periodontitis in a setting of hypothyroidism. Samples for microbiological investigations were taken from dental surfaces (on the border between hard tissue and gums in the interdental spaces). The isolated pure cultures were identified by their morphological, tinctorial, cultural and biochemical properties.

The oral dysbiosis occurring in a setting of periodontitis in rats is chiefly characterized by increased quantity of coccal forms and by increased candidal inoculation; these organisms cumulatively inhibit the growth of normal microbial flora, such as Lactobacilli, bacteroids and Bifidobacteria. The periodontitis in a setting of thyroid dysfunction increases both the species variety and the quantitative counts of oral microbial flora, with predominance of such microbial organisms as Staph. aureus, E. coli, E. faecalis, Candida albicans and P. aeruginosa. Comparative assessment of intensity of oral microbial colonization in hyper- and hypothyroid animals with periodontitis has demonstrated significant changes only for the strains of S. aureus, yeast-like fungi and Candida albicans, which were predominant in hyperthyroid rats.

Both hyperthyroidism and hypothyroidism exacerbate changes in the qualitative and quantitative structure of oral microbiocenosis in case of experimental periodontitis.