Quantitative Detection Of Porphyromonas Gingivalis And Changes Of Clinical Index After Removal Of Orthodontic Appliances

Objective: The precalence of malocclusion in our country reach as 83.1%. With the people's living standards and awareness of oral hygiene care improvement, demands of orthodontic treatment are becoming more and more. Orthodontic treatment has improved esthetic appearance and functional for malocclusion patients as well as make adverse effect to oral hygiene Maintenance and periodontal tissues health .In clinical most patients develop generalized gingivitis who are found gingival enlargement or gingival recession lead to"black triangle"durning orthodontic treatment or When a fixed orthodontic appliance is placed. The goal of this study was to evaluate Clinical Index and Porphyromonas gingivalis factors associated with orthodontic appliances during an episode of gingival inflammation and the impact of appliance removal on periodontal health.Methods: 20malocclusion patients aged 12-29years were selected with clinical signs of gingival inflammation at the final phase of orthodontic treatment (appliance removal) ,divide two groups including 10 adults(19-29years) and 10 adolescents(12-15years).All the patients were trea- ted by straight wire appliance. Plaque index(PLI), gingival index(GI), sulcus bleeding index(SBI) and probing depth(PD) of observed teeth were examined and subgingival plaques were collected from 31,32,41and 42 at prior to appliance removal (baseline) and 1,3 and 6 months after appliance removal . We used real-time quantitative PCR to detecting and quantitating the total counts of bacteria and the counts of P.gingivalis in each sample.Results:1. Microbiological results:The prevalence of P.gingivalis decreased from baseline to the sixth month after fixed appliance removal in two groups, and significant change was found in sixth month(P<0.05); The numbers of P.gingivalis significantly reduced from baseline to the sixth month in two groups(P<0.05), The numbers of total bacteria become lower after removal but no significant difference was found.; The proportion of P.gingivalis in subgingival plaque decreased from baseline to the sixth month in two groups( P<0.05) .In addition, the adults'proportion of P.gingivalis were significantly higher than the adolescents at baseline to sixth month (P<0.05).2. Periodontal indexes: PLI,SBI and PD significantly decreased from baseline to the sixth month after fixed appliance removal both in adult and adolescent groups. PLI and PD in adolescent group were significantly higher than the adolescents at baseline to sixth month (P<0.05).Conclusions: Fixed orthodontic appliances effect to oral hygiene Main- tenance, inducing the increase of suspected periodontal pathogens, which lead to inflammation of periodontal tissue during the orthodontal treatment. After fixed appliance removal,most of patients can recover periodontal tissue health in good oral hygiene.With the similar of SBI and PD ,the percentage of P.gingivalis in subgingival plaque decreased, which suggest the the percentage of P.gingivalis are closely associated with periodontal status and error smaller than others. The prevalence of P.gingivalis significantly reduced in sixth month after removal,this result suggest the change of environment of oral microbes need some time. The adults'proportion of P.gingivalis were significantly higher than the adolescents. The finding implied P.gingivalis might grow faster in adult subgingival plaque. PLI , PD and SBI in adolescent group were significantly higher than the adolescents .The result showed that the periodontal tissue of adolescent has a higher inflammatory response than adult. TaqMan real-time polymerase chain reaction has a high sensitivity and specificity .It was demonstrated the broad potential of application on detection of oral microbes .