UCLA

Background:The most popular method for addressing malocclusion is by using fixed or removable orthodontic devices. However, these appliances can inadvertently accumulate plaque shortly after their application, which can lead to an imbalance in the bacterial population. This bacterial dysbiosis could increase the risk of several health issues, including dental caries, white spot lesions, periodontal diseases, and even metabolic diseases. This research investigates the changes in the gingival and plaque indices and the bacterial composition following the removal of orthodontic devices. Moreover, this work explores the ambiguity surrounding whether microbiological and clinical changes experienced by patients during orthodontic treatment are reversible post-therapy and compares the changes for fixed and clear aligner Orthodontic appliances Objective: To analyze the initial changes in clinical parameters and plaque levels of periodontal pathogens after orthodontic treatment with fixed or removable appliances. Materials and Methods: The subjects consisted of 14 patients completing orthodontic treatment ready for debonding. The Plaque Index and Gingival Index were measured as periodontal parameters. Both the plaque and gingival indexes were obtained from the central incisors, lateral incisors, canines, and first molars of both arches. Plaque and periodontal parameters were obtained at the following three-time points: at debonding (T0), 1 month (T1), and 3 months (T2) after debonding. Deep 16S rRNA sequencing was performed for the supra gingival plaques to analyze the correlation with the clinical indexes and to see the microbial community composition after debonding at 3-time points (T0, T1, and T2). Results: The Fixed appliance (FA) group had a statistically significant greater overall GI score than the Clear aligner (CA) group at time T0 (p<0.01) and T2 (p<0.01). The FA group also had a statistically significant greater anterior and posterior GI score at T0 (p<0.01) and T2 (p<0.05) as compared to the CA group. Similarly, the patients with Fixed appliances generally showed statistically significantly greater overall, anterior, and posterior PI scores at all time points T0 (p<0.01), T1 (p<0.05), and T2 (p<0.05) as compared to the CA group. A greater reduction in plaque index was observed for FA group from T0-T2 which was statistically significant at p<0.01 as opposed to the CA group. The microbiological analysis revealed no correlation between the relative abundance of different microbes and the timepoint after debonding for either the FA or CA group. However, the FA group had higher PI and GI scores relative to the CA group. Further, the FA group showed higher levels of Neisseria and Veilonella which are known to be health associated bacteria. iv Conversely, the CA group was observed to be associated with Neisseria, Capnocytophaga and Leptotrichia at lower plaque and gingival index scores with respect to the FA group. Alpha – and beta-diversity showed no significant differences in the composition of supragingival plaque when correlated with the Plaque index, Gingival Index, and the various time points. Conclusion: This study's findings align with prior research, indicating changes in clinical indices after orthodontic devices are placed in the mouth. We observed a general trend towards reduced clinical index parameters after removal of both types of orthodontic appliances. Patients who had fixed appliances showed higher Gingival and Plaque indices compared to those with clear aligners, although these indices decreased over time for both groups. Our microbial evaluation revealed higher levels of Neisseria and Veilonella, both generally associated with oral health, in the fixed appliance group. Meanwhile, the clear aligner group demonstrated links with Leptotrichia, Capnocytophaga, and Neisseria at lower plaque and gingival index scores. Notably, our analysis did not find any correlation with harmful bacteria related to periodontal disease or dental caries after the removal of Orthodontic appliances in either group.