Detection Of Suspected Periodontal Pathogens In Patients With Alveolar Bone Loss After Orthodontic Treatment

Background The precalence of malocclusion in our country reach as 83.1%. Many researchers found that the placement of the fixed orthodontic appliances could disturb the composition of microorganisms in subgingival plaque and increase the suspected periodontal pathogens. A dynamic balance exists between the host defense system and pathogens in the gingival crevice. The host defense system is affected by many factors. Some researchers believe that the damage of periodontal tissue due to orthodontic treatment will not last for a long time. When the fixed orthodontic appliances are removed, the pathogens will lost the long-time living environment, and the periodontal health will recover. In some patients with alveolar bone loss due to the periodontitis during orthodontic treatment, the periodontitis will keep on progressing until the teeth are lost. It isn't clear whether the orthodontic treatment affords the facilities for specific suspected periodontal pathogens to colonize in subgingival plaques which leads to alveolar bone loss.Objective Through the evaluation at different time intervals of the clinical indices and suspected periodontal pathogens factors in sites with alveolar bone loss during orthodontic treatment, to analyze whether there exist the specific suspected periodontal pathogens leading to alveolar bone loss during orthodontic treatment.Methods 20 patients at the final phase of orthodontic treatment (appliance removal) were selected, who had alveolar bone loss during orthodontic treatment. Probing depth(PD), bleeding on probing(BOP) and gingival index(GI) of observed sites were examined, and polymerase chain reaction(PCR) analysis was used to detect six species of suspected periodontal pathogens at baseline and 30 days there after . all of the patients given periodontal treatment at baseline.Results The ratio of Porphyromonas gingivalis, Prevotella intermedius , Haemophilus actinomycetemcomitans, Tannerella forsythensis, Fusobacterium nucleatum , and Treponema denticola in sites with alveolar bone loss was 39.1%, 30.0%, 14.9%, 46.0%, 69.0% and 60.9%. The ratio of sizes of bleeding on probing was 100%, and the average probing depths was 4.5mm. About 81.6% sizes with alveolar bone loss recorded 2 of gingival index, and 18.4% sizes recorded 3. Thirty days aftersupragingival and subgingival scaling, the detective ratio of Porphyromonas gingivalis, Tannerella forsythensis, Fusobacterium nucleatum, Treponema denticola and Haemophilus actinomycetemcomitans decreased whencompared with that of the basline(P < 0.05 or P<0. 01), and the manifestation of clinical status also showed significant changes. But the ratio of Prevotella intermedius did not show statistic change(P>0.05).The finding implied that fixed appliances might change the living environment of oral microbes, inducing the increase of suspected periodontal pathogens,which can lead to the alveolar bone loss in susceptible individuals. Peridondotal health can signigicantly recover when given orthodontic appliance removal and professional prophylaxis.