Microbiologic changes in subgingival plaque after removal of fixed orthodontic appliances

Abstract

Objective: To evaluate changes that occur in the subgingival microbiota after removal of fixedorthodontic appliances using polymerase chain reaction (PCR). Materials and Methods: Thirty orthodontic patients (11 males and 19 females; aged 20 ± 7.3 yr)were included in this study. Subgingival plaque samplings were gathered from the disto-buccal gingivalcrevice of the left upper central incisors and the left lower central incisors, and from the mesio-buccalgingival crevice of the left upper first molars and the left lower first molars, at two different times: 2weeks before appliance removal (T1), and 3 months after appliance removal (T2). DNA was extractedfrom the samples and the 16S rRNA-based PCR detection method was used to determine the prevalenceof Actinobacillus actinomycetemcomitans, Tannerella forsythia, Campylobacter rectus, Eikenellacorrodens, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, and Treponemadenticola, which are considered as putative periodontopathogens. Results: The frequency of positive sites at T1 and T2 was 65% and 43.3% for C. rectus, and 53.3% and 30.8% for E. corrodens, respectively. For the other bacteria, the frequency tended tobe reduced between times. Conclusion: Periodontopathogens during orthodontic treatment were significantly reduced within3 months of appliance removal. However, how long it takes to return to the preorthodontic compositionof the subgingival microbiota and whether it happens at all remain to be seen. (AngleOrthod. 2009;79:1149-1155.