Background: The objective was to analyze clinical, microbiological, and immunological periodontal parameters in patients in corrective orthodontic treatment. Materials and methods: Twenty-eight patients were selected. Plaque index (PI), bleeding on probing (BOP), width of keratinized gingiva, levels of 40 bacterial species, and of 3 cytokines (IL-1β, MMP-8, and TNF-α) in gingival crevicular fluid (GCF) were evaluated at T0, before orthodontic treatment; T1, 6 months; and T2, 12 months posttreatment. Non-parametric, Friedman, Wilcoxon, ANOVA, and Spearman correlation coefficient tests were used for statistical analyses, with the significance level of 5%. Results: No significant difference was found for the width of keratinized gingiva, but PI presented a significant increase at T1 and T2 (p < 0.05) when compared with T0. The percentage of sites with BOP increased significantly from T0 to T1 (p < 0.05); however, at T2, the values decreased and did not differ anymore from T0 (p > 0.05). In the microbiological analysis, red complex pathogens were in significantly greater proportions in T2 compared with T0 (p < 0.05). There was no statistically significant difference in the cytokine levels between the periods but there was a positive correlation between BOP and IL-1β (r = 0.49 p = .01) and TNF-α (r = 0.39 and p = .05). Conclusion: In conclusion, corrective orthodontic treatment caused clinical periodontal alterations regarding biofilm accumulation and gingival bleeding, with alteration of periodontopathogens.
This study evaluated the effectiveness of carbon dioxide (CO2) laser combined or not with fluoride application on the surface microhardness of enamel adjacent to orthodontic brackets. Fifteen human molars were selected from which 30 enamel fragments measuring 4 mm2 were obtained. The fragments were embedded in PCV tubes with acrylic resin and prepared using water abrasive paper, felt disks and alumina. Orthodontic brackets cut in half were bonded to enamel and 3 microhardness readings were performed on the adjacent surface, as follows: initial, after cariogenic challenge and final. The specimens were divided into the following 3 groups (n=10): Group C: control, Group L: irradiated with CO2 laser, and Group FL: topical fluoride application and CO2 laser irradiation. After initial reading, the specimens were placed in a demineralizing solution for 32 h and the second reading was to verify if demineralization was uniform in all groups. After the treatments, the specimens were submitted to DES-RE cycling for 8 days followed by final surface microhardness reading. The data were analyzed statistically using ANOVA and Duncan test (α=0.05). At the final measurement Group FL obtained higher microhardness value than Groups C and L (p<0.05). Groups L and FL were statistically superior to Group C (p<0.05). Irradiation with CO2 laser around orthodontic brackets combined or not with topical fluoride application was effective to increase the surface microhardness of enamel.
This study aimed to test the hypothesis that Streptococcus mutans contamination levels differ according to the type of the orthodontic ligature. Thirteen patients were selected. Each quadrant was randomly subjected to one of the following ligature-use protocols: I) elastomeric chain, II) steel ligature crossed over the archwire, III) steel ligature crossed under the archwire, and IV) steel ligature in a figure-eight pattern under the archwire. After seven days, the devices were removed and the Streptococcus mutans colony-forming unit count per mg of biofilm weight was determined. Twelve specimens (n=3) were also processed for scanning electron microscopy analysis. ANOVA and Tukey-Kramer test were used for comparisons to assess S. mutans differences between groups at a 5% significance level. There was no statistical difference in detectable levels of S. mutans among the groups (p=0.294). Scanning electron microscopy results showed abundant biofilms and microbial contamination in all groups. In conclusion, S. mutans contamination levels are similar in the different orthodontic ligatures.
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