engleski

The Effect of Fixed Orthodontic Appliances on Composition of Bacterial Flora in the Oral Cavity

It is well known that fixed orthodontic appliances increase caries risk. The aim of this study was to individualize the change in the composition of cariogenic bacteria caused by fixed orthodontic appliance. Qualitative evaluation of the level of infection with mutans streptococci was determined by analyzing samples of stimulated saliva (32 patients). The samples were taken before placement of fixed orthodontic appliance and 3 months from the beginning of therapy. Two tests were performed on each sample. The concentrations of levels of Streptococcus mutans and S. sobrinus were determined using a classic cultivation method, and a two-stage PCR was performed [Oho et al.: Oral Microbiol Immunol 2000 ; 15: 258– 262]. Before placement of the orthodontic appliance S. sobrinus could not be detected by either method, whereas the second test revealed its presence in 9.4% of cases using the PCR method and in 6.3% with cultivation. In the second test S. mutans was detected with the PCR method in 25% of the samples, with an increase of 9.4%, whereas the cultivation method detected its presence in 16% with an increase of 6.2%. The Spearman test showed high correlation between bacterial concentrations by the PCR and classic cultivation methods ( S. mutans  = 1.0, p ! 0.001 ; S. sobrinus  = 0.80, p ! 0.001). Three months into orthodontic therapy with a fixed appliance there were no changes in the strain of S. mutans , although there was some increase in the combined colonization of S. mutans and S. sobrinus . Detecting both species using PCR and classic cultivation is almost identical, which confirms that these microbiological tests are applicable and equally reliable in everyday practice.

S. mutans; S. sobrinus; cariogenic bacteria

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