| Fixed orthodontic therapy is an effective and common method for treating malocclusions in contemporary orthodontics.One of the common side effects during orthodontic therapy is periodontal complication including gingivitis and periodontitis.It is still unclear whether the periodontal changes in orthodontic therapy could be reversible after the removal of appliances.Most studies indicated that gingival changes were only temporary and could be reversible,while a few of researches reported a significantly clinical attachment loss during orthodontic therapy.A prospective study discovered that orthodontic accessories had a negativeimpact on periodontal parameters,moreover these changes were only partially reversible posttherapy.Bollen et al.summarized the studies on the effect of orthodontic treatment to periodontal status since 1980-2006 and found that there is no assertive evidence that orthodontic treatment is beneficial to periodontal health maintenance and may even cause minor damage to periodontal tissue.These two contradictory conclusions may be caused by different methods of attachment level examination,different observation times,and individualized differences in immunity to pathogenic bacteria.Moreover,there are significant differences between the psychological development of adolescents and adults.Besides,the treatment compliance and the degree of attention to oral hygiene are also different.Hence,the periodontal conditions may be significantly different during orthodontic treatment.The purpose of this study was to compare the periodontal clinical status of orthodontic patients in different age groups,to detect the periodontal pathogens in the worst affected group,and to analyze the changes in detection rate,absolute number and percentage of periodontal pathogens before and after orthodontic treatment.Part 1:Analysis of periodontal status of orthodontic patients atdifferent agesOBJECTIVE:To investigate the periodontal status of adolescent and adult orthodontic patients,then to compare the effect of orthodontic treatment on periodontal tissues of different teeth in the worst affected group.MATERIALS AND METHODS:The malocclusion patients seeking orthodontic treatment from the Department of Orthodontics of Jinan Dental Hospital from May 2014 to October 2014 were selected.The age group was divided into adolescent group(11-16 years old)and adult group(over 16 years old).Among the patients who met the inclusion criteria and were selected into this study,41 were adolescents and 38 were adults.Periodontal examination was performed respectively on the two groups of patients before bonding appliances(To)and 6 months after bonding appliances(Ti).The periodontal examinations were conducted applying Williams scaled periodontal probe to examine the proximal and distal middle buccal points of the right maxillary first molar,the right first premolar.(If the first premolar is extracted,choose the second premolar),the right upper central incisor,the left central incisor,the left first premolar(or the second premolar),and the left first molar.Oral examinations included plaque index(PLI),gingival index(GI),sulcus bleeding index(SBI),and probing depth(PD).At baseline and 6 months after the bonding the changes of periodontal clinical indexes were recorded and compared between the two groups to discover which group the effect of fixed appliance on periodontal tissues was more obvious.Subsequently,this study further analyzed the changes of periodontal clinical indexes of different teeth in the worst affected group.RESULTS:(1)There was no significant difference in PLI,GI and SBI between adolescent and adult groups before treatment.Compared with the values at baseline,the PLI,GI and SBI values of the adolescent group and adult group were both higher after treatment(both P<0.001),and the adolescent group was higher than the adult group(P<0.05,P=0.001,P<0.001).The difference in PLI between the adolescents before and after treatment was greater than that in the adult group(P<0.001,P=0.001,P<0.001),hence it could be considered reasonably that the changes in PLI,GI,and SBI values in the adolescent group were greater than those in the adult group.PD between the adolescent group and the adult group showed that the PD value of the adult group before treatment was higher than that of the adolescent group(P<0.001),and the PD values of the two groups were higher than those before the treatment(P<0.001),and there were no statistical differences between the groups.The PD difference in the adolescent group before and after treatment was greater than that in the adult group(P<0.05).It could be considered that the change in PD value in the adolescent group is higher than in the adult group.(2)Based on the analysis above,itcould be deduced that compared with adults,fixed appliances have a more obvious effect on adolescent periodontal status.Before treatment,there was no significant difference in GI values between different teeth.While,after treatment,the GI values were statistically different among different parts(P<0.001).Further comparison showed that there were significant differences between UR6 and UR1,UR6 and LR6,UR4 and UR1,UR4 and LR4,UR4 and LR6,UR1 and LL1,LL1 and LR4,LL1 and LR6(P<0.05).Before and after treatment,the GI difference among different teeth were statistically different with each other(P<0.001).Further comparison showed that the difference of GI difference was statistically significant between UR6 and UR4,UR6 and UR1,UR4 and UR1,UR4 and LR4,UR4 and LR6,UR1 and LL1,LL1 and LR4,LL1 and LR6(both P<0.05),and there was a significant increase in gingival index of UR4,LL1 and UR6.There was no significant difference in PD values between different teeth before treatment.After treatment,the PD value was statistically significant differences between different teeth(P<0.001).Further comparison indicated that the differences between UR I and UR6,UR 1 and UR4,UR1 and LL1,UR1 and LR6 were statistically significant(both P<0.05).The PD difference was statistically different between different teeth positions before and after treatment(P<0.05).Further compared the two groups,it could be concluded reasonably that there were statistically significant differences of PD difference between UR1 and UR6,UR1 and UR4,UR1 and LL1,UR1 and LR6(all P<0.05).The probing depth of UR1 was the smallest,and the probing depth of UR4,LL1,and UR6 was increased more obviously.CONCLUSION:After bonding appliances,gingival inflammation occurred in both the adolescent and adult group.Compared with the adult group,the effect of the fixed appliance on the periodontal tissue of the adolescent group is more severe.Six months after the appliance,in adolescent group the gingival inflammation of the maxillary first premolar,lower central incisor and maxillary first molar was more grievous than in other teeth.PART 2:Detection of Porphyromonas gingivalis and its fimA genotypein the subgingival plaque during and after orthodontic treatmentOBJECTIVE:In this study,we investigated the association between the prevalence of Porphyromonas gingivalis-specific fimA genotypes and periodontal health status in adolescent orthodontic patients,to identify the pathogencity of Porphyromonas gingivalis during orthodontic therapy.MATERIALS AND METHODS:63 malocclusion patients seeking orthodontic treatment and 58 orthodontic patients who were about to debond the appliances,ranging from 11 to 16 years old,were enrolled in the case group A and case group B.The control group was comprised of 56 periodontally healthy individuals without receiving orthodontic therapy matched for age and sex,selected from physical examination program of primary and secondary schools in Jinan.Periodontal examinations and sample collections were performed respectively to the two case groups at different time points including bonding appliance(Tao),three months after bonding(Ta1),six months after bonding(Ta2),and debonding appliances(Tbo),three months after demolishing(Tb1),and six months after demolishing(Tb2).Samples were collected between 10am and 12am.The maxillary first molars,the first premolar(or the second premolar),and the lower central incisor on both sides were selected as sampling sites.The 16S rRNA-based PCR technique was applied to detect the prevalence of Pg and fimA genotypes in subgingival plaques.RESULTS:(1)After bonding appliances,the GI values of case group A gradually increased.After debonding appliances,the GI values of case group B decreased significantly.(2)At baseline(Tao),the detection rate of Pg in case group A was 31.7%.After three months,the detection rate of Pg was increased to 79.3%,which was significantly higher than that at baseline(P<0.001).When it came to six months(Ta2),the detection rate dropped down to 66.7%,but still above the baseline level(P<0.001).For group B,when the appliances were removed(Tb0),the detection rate of Pg was 71.4%,which was significantly higher than that of the control group(P<0.001).The detection rate decreased to 46.4%and 30.4%respectively at three months and six months after removing the appliances,and there were no significant differences compared with control group.(3)For group A,at the baseline(Tao),the fimA type ?(11.1%)and the type ?(9.5%)were higher than those of other genetypes.After three months(Tai),the detection rate of fimA type ?,type ? and type ? was 15.9%,23.9%and 33.3%respectively,which were significantly higher than those at baseline(P<0.05,P<0.001,P<0.05).At six months(Ta2),the detection rate of type ?(12.7%),type ?(20.6%),and type ?(27%)were slightly lower than those at Tai,but the detection rate of type ? and type ? were still higher than those at baseline(both P<0.05).In the case group B,when the appliance was removed(Tbo),the detection rates of fimA type ?(16.1%),type ?(26.8%)and type ?(26.8%)were significantly higher than those of the control group(P<0.05,P<0.001,P<0.05).At three months after debonding appliances(Tbi),the detection rates of type ?(8.9%),type ?(10.7%)and type ?(21.4%)decreased.Compared with Tbo,the detection rate of type ? decreased significantly(P<0.05).Six months after debonding the appliances(Tb2),the detection rates of type ?(7.1%)and type ?(8.9%)were significantly lower than those of Tbo(P<0.05),and for all genotypes,there were no significant differences compared with the control group.(4)Since the detection rate of Pg was the highest in stage Ta1,data from Ta1 was used to analyze the relationship between the detection rate of fimA genotypes and the gingival index.Regarding GI,there was no significant difference between fimA ?/?/?/Ib-positive samples and negative samples.However,the GI of fimA ?,?-positive samples was significantly higher than that of negative samples(P<0.01).CONCLUSION:After binding the appliance,Pg and its fimA ?,?,? genetypes increased significantly,and the detection rate of Pg fimA ? type with the weakest pathogenicity increased the most.After debonding the appliances,the detection rate of Pg and its fimA ?,? and ? was significantly reduced.6 months after debonding the appliances,the Pg fimA genotypes returned to normal.For orthodontic patients,the gingival index grade is only related to the detection rate of fimA type ? and type ?.Part 3:Profiling of subgingival plaque biofilm microbiota in adolescents during and after orthodontic treatmentOBJECTIVE:In this study,we quantify subgingival pathogens of A.actinomycetemcomitans,P.gingivalis,P.intermedia,T.forsythia and total bacteria with the real-time PCR at different time points during and after orthodontic treatment to assess whether the microbial and periodontal parameters could be reversible after removal of orthodontic appliances.MATERIALS AND METHODS:21 malocclusion patients seeking orthodontic treatment and 19 orthodontic patients about to debond appliances,ranging from 11-16years,were enrolled in the case group A and case group B.The control group was comprised of 21 periodontally healthy individuals without receiving orthodontic therapy matched for age and sex,selected from physical examination program of primary and secondary schools in Jinan.The prevalence,counts and percentage of A.actinomycetemcomitans,P.gingivalis,P.intermedia,T.forsythia and total bacteria were determined by real-time PCR at different time periods.Periodontal examinations and sample collections were performed respectively to the two case groups at different time points including bonding appliance(Ta0),three months after bonding(Ta1),six months after bonding(Ta2),and debonding appliances(Tb0),three months after demolishing(Tb1),and six months after demolishing(Tb2).RESULTS:(1)After bonding fixed appliances,the periodontal parameters of case group A gradually increased.Compared with baseline,the gingival index,gingival bleeding index,and periodontal probing depth were significantly higher at 3 months and 6 months after bonding appliance(P<0.001).After debonding the appliances,for case group B,the gingival index and the gingival bleeding index were reduced significantly.6 months after debonding appliances,there were no statistically significant differences in these two indexes between case group B and the control group.The probing depth decreased gradually,but it was still higher than the control group at 6 months after debonding(P<0.05).(2)For case group A,the difference of detection rate of Aa,Pi and Pg between baseline the 6 months after bonding appliance(Tao-Tai)was not statistically significant,but the detection rate of Tf increased from 61.90%to 90.48%(P<0.05).After debonding appliances in case group B(Tbo-Tb2),the detection rates of Aa,Pg and Tf gradually decreased,but the difference was not statistically significant,and there were no statistically significant differences between control group and case group B.From Tbo to Tb2,the detection rate of Pi decreased from 93.73%to 52.83%,the difference was statistically significant(P<0.05),and the detection rate of Tbo and Tb1 was statistically different from the control group(P<0.05).At Tb2,there was no statistically significant difference compared with the control group.(3)After bonding appliance,there was no significant change in the number and percentage of Aa and the total number of bacteria.From Tao to Ta2,the number and percentage of Pi,Pg and Tf were significantly increased(P<0.05).At Tbo,there was no significant difference in the number and percentage of Aa and the total number of bacteria between the case group B and the control group.The number and percentage of Pi,Pg and Tf were significantly higher than those in the control group(P<0.001,P<0.05,P<0.05).After debongding the appliances,there was no significant change in the number and percentage of Aa.From Tbo to Tb2,the number of Pi,Pg,Tf and the total number of bacteria decreased significantly(P<0.001,P<0.05,P<0.05,P<0.05);the percentage of Pi also decreased significantly(P<0.001).Although the percentage of Pg and Tf were also reduced,the changes were not statistically significant.At Tb2,there was no significant difference in the number and percentage of Aa,Pg,Pi,Tf,total number of bacteria between case group B and the control group.CONCLUSION:For adolescent,after bonding the fixing appliance,gingivitis occurs immediately.The detection rate,absolute number,and percentage of some major periodontal pathogens in subgingival plaques increased significantly.6 months after debonding appliances,the periodontal condition basically returned to normal and the depth of probing was slightly higher. |
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