Comparison of the effects of mouthwash use on bacterial plaque and oral flora in patients treated with different types of rapid maxillary expansion appliances

Our aim was to investigate the effects of mouthwashes and appliances type on the oral microflora, plaque index, and modified gingival index in the patients who underwent rapid maxillary expansion. 50 patients who had transverse maxillary deficiency in the treatment group were categorized into 4 groups patients treated with either Hyrax or full coverage acrylic bonded expanders and either using mouthwash or not. 22 patients in the control group were also categorized into 2 groups according to mouthwash use and a total of 6 groups were formed. Patients who used mouthwash were asked to use 'Colgate Plax' once each evening. The saliva and throat culture samples were collected at the beginning of the treatment (T0), at the end of the second month (T1), and at the end of the third month of the treatment (T2) and plaque and modified gingival indices were evaluated at the same time. The collected samples were quantitatively analyzed for S.mutans, Lactobacillus, Candida, S.salivarus, S.mitis, S.aureus in saliva and for S.pyogenes in throat culture. Friedman and Post-Hoc Wilcoxon Signed Rank tests were used for intragroup comparisons, and Kruskal-Wallis and Post-Hoc Mann-Whitney U tests were used for intergroup comparison. The number of S. mutans, Lactobacillus and Candida were found to increase significantly in the patients treated with both appliances. The number of Lactobacillus in patients treated with full coverage acrylic bonded expander was observed to be significantly higher compared to the control groups, whereas there were no significant changes in the number of other bacteria in the intergroup comparisons. Colgate Plax mouthwash had no significant effect on the oral microflora and indices. While the index values increased in both appliance types during the treatment, modified gingival index increment was significantly higher in the full coverage expander group, compared to the other groups. Rapid maxillary expansion treatment causes an increment in plaque accumulation, plaque and modified gingival indices and the number of bacteria which are responsible for demineralization. While the appliance type had no significant effect on the bacteria number, it could be concluded that full coverage expander is more advantageous than Hyrax expander in terms of plaque and modified gingival indices. Therefore, Hyrax expander can be preferred especially in individuals who do not have adequate oral hygiene. Keywords: Full coverage acrylic bonded expander, Hyrax, Mouthwash, Oral microflora, Rapid maxillary expansion