it often leads to the destruction of the joint due to the presence of inflammatory agents in the synovial fluid . it is one of the most common forms of arthritis afflicting approximately 1% of the world 's population with a female to male ratio of 3:1 . the etiology of ra is yet to be completely identified , but some arteriogenic stimulants seem to be responsible for activating the inflammatory response in this disease . infections , mediators like cytokines , impaired function of immunoglobulins and the immune system have also been suggested as the possible mechanisms involved . juvenile idiopathic arthritis ( jia ) was suggested by the international league of association for rheumatology in 1997 as a substitute for the terms juvenile chronic arthritis and juvenile ra . jia is a type of chronic arthritis with an onset before the age of 16 years . it is a major connective tissue disorder in children and adolescents ( with an incidence rate of 0.07 - 4.01 in 1000 adolescents and a female predilection ) . etiology of jia is unknown , but the role of immune system disorders in this respect has been documented . increased production of cytokines , immunogenetic diseases , and some viral infections are among the proposed etiologies . in these two forms of arthritis , increased levels of various cytokines such as interleukin-1 ( il-1 ) , interleukon-2 receptor ( il-2r ) , il-6 , tumor necrosis factor alpha ( tnf - alpha ) and interferon gama ( if gama ) are detected in the synovial fluid and serum of patients . apparently , these cytokines stimulate the synovial cells to release hydrolytic enzymes like collagenase that is , the main culprit in tissue destruction process . low - level of t helper 2 ( th2 ) in ra and jia patients results in prolonged inflammation and development of systemic signs of inflammation such as increased serum level of acute phase proteins . on the other hand , periodontitis is a chronic disease associated with the destruction of tooth - supporting structures like collagen fibers and alveolar bone . it is caused by a group of pathogenic microorganisms , and its continuation depends on the body 's inflammatory and immune responses . periodontitis is the inflammation of the periodontal tissues associated with the destruction of gingiva and connective tissue attached to the tooth and is manifested in three general forms of chronic , aggressive and as a manifestation of systemic disease . at present , scaling and root planning , periodontal flap , and antimicrobial therapy as an adjunct to mechanical debridement are offered to treat periodontal patients . in addition to the involvement of bone and connective tissue in these conditions , host 's immune system and function of neutrophils play a significant role in jia and periodontitis . also , in all three conditions , cytokines and their receptors like il1  , il2 , il6 , prostaglandin e2 and tnf alpha play a role in tissue destruction and bone loss . polymorphism of il1 , il1 and il4 genes has been observed in both jia and periodontitis association of hla - dr4 alleles in genetic structure of ra and aggressive periodontitis patients are among other similarities of these conditions . use of nonsteroidal anti - inflammatory drugs for treatment of ra and jia decreases the progression of periodontal disease and associated bone loss in patients suffering from arthritis ; however , this correlation can be an outcome of the upper limb movement limitations that result in patients decreased ability to maintain their oral and dental hygiene . temporomandibular joint ( tmj ) involvement in some ra and jia patients can cause limited access to the oral cavity . recently , studies conducted on the relationship of these two diseases have reported controversial results . in some studies , more severe periodontal conditions have been reported in ra and jia patients as compared to healthy controls . considering the little information regarding the relationship between periodontal disease and jia and controversial correlations with ra , the present study aimed to determine the relationship of periodontal disease with ra and jia . this case - control study was conducted on ra and jia patients presenting to the rheumatology and pediatric clinics of imam khomeini hospital in tehran , iran during 2012 - 2013 . the controls were healthy subjects that matched our cases in terms of age and gender . the sample size of the study was determined based on similar previous studies and consult of statistion . data were collected through observation , examination , and interview and the obtained results were recorded in a questionnaire . a total of 30 adult ra patients who had been referred consequently to the rheumatology clinic of imam khomeini hospital were selected , and their arthritis was confirmed by an experienced rheumatologist according to the the american rheumatism association criteria.- also , 30 adolescents ( below the age of 16 ) whose jia diagnosis had been confirmed by a pediatrician were chosen in the pediatric clinic of imam khomeini hospital . the control group included 30 healthy adults selected among those presenting to a private practice office and 30 healthy adolescents ( below the age of 16 ) presenting to a pediatric dental office . understudy sample size was determined according to the most relevant study ( with10% increase to adjust for possible patient loss ) . the exclusion criteria were pregnancy , smoking , and any other systemic disease affecting periodontal conditions and use of antibiotics in last 6 months . all patients attending the study were thoroughly informed about the study and related examinations and a written informed consent was obtained from them . all data about their rheumatologic conditions in ra group were obtained by a rheumatologist and the questionnaire for joint pain , and inflammation was filled out for patients . as previously mentioned , rheumatoid workup was performed on jia patients by a pediatric rheumatologist and joint pain and inflammation questionnaire was filled out for them . periodontal examinations of patients were done within 10 - 15 days after rheumatologic examinations in the rheumatology clinic of imam khomeini hospital by a trained dental student . examinations were done at the rheumatology and pediatric wards and clinics using a williams probe . since some of the patients were hospitalized , all subjects were examined on the hospital bed using a headlight . measurements for plaque index ( pi ) , bleeding on probing ( bop ) , pocket depth ( pd ) and clinical attachment level ( cal ) were performed for all teeth except for the third molars and maximum values of indexes were recorded for each tooth . prior to the study , intra - examiner calibration was done through repeated examinations by the student and their accuracy was confirmed by a periodontist . test subjects also completed the patient assessment ( pa ) form and children health assessment questionnaire ( chaq ) approved by the american college of rheumatology in order to determine disease severity from their point of view . eventually , erythrocyte sedimentation rate ( esr ) was performed for case subjects ( ra and jia patients ) to determine the amount and severity of inflammation . the following indexes were also compared between case and control groups : mean percentage of pi , mean percentage of sites with bop , mean percentage of sites with cal > 3 mm , mean percentage of sites with pd > 4 mm , mean cal values , mean rate of pd , and tmj status ( pain , inflammation / swelling ) . in the case groups , correlations between periodontal parameters and esr , number of painful or inflamed joints , patient assessment scores , and chaq scores as the indexes for determining the severity of arthritis were evaluated . data were analyzed using statistical package for the social sciences ( spss ) version 16 software ( spss inc . , mean , standard deviation , standard error , minimum and maximum values of the variables were determined and reported for both groups of case and control . comparison of periodontal indexes in the two groups was done using mann - whitney u nonparametric test . the correlations between periodontal indexes , serologic findings of disease and patients assessment of disease severity were evaluated and compared using spearman and pearson 's correlation coefficients ( in case of the normal distribution ) . gender frequency in the case and control groups was analyzed with chi - square test . also , participation in the study was voluntarily , and patients received oral health care instructions . it should be mentioned that examinations required for this study did not interfere with patients treatments and all examinations were done under the supervision of a specialist . this study was approved by the ethics committee of research council , school of dentistry , shahid beheshti medical university . this study was done on 30 healthy adults , 30 healthy adolescents and 30 adults with ra and 30 patients with jia . of a total of 60 adults , 48 ( 80% , 24 of cases and 24 of controls ) were females and 12 subjects ( 20% , 6 cases and 6 controls ) were males . in adult ra patients , mean esr was 22.53  5.99 ( range 11 - 32 ) , mean patient assessment score was 15.69  3.55 ( range 10.5 - 25 ) , mean number of inflamed joints was 3.0  1.44 ( range 1 - 6 ) , and mean number of painful joints was 13.1  2.07 ( range 10 - 19 ) . the mean age of ra subjects was 42.73  7.49 years ( range 29 - 55 years ) . in the adult control group of ra , the mean age of subjects was 42.63  7.64 ( range 29 - 56 ) . therefore , comparison of the ra and healthy groups in terms of periodontal parameters was done with mann - whitney u - test [ table 1 ] . this test demonstrated that the pd ( p < 0.0001 ) , cal ( p < 0.002 ) , percentage of sites with pd > 4 ( p < 0.002 ) , percentage of sites with cal > 3 ( p < 0.001 ) , percentage of sites with bop ( p < 0.0001 ) and pi index ( p < 0.0001 ) values in adult ra patients were significantly higher than those of controls . comparison of periodontal parameters in control and ra patients table 2 demonstrates the significant and insignificant correlations between understudy variables in adult ra patients using spearman 's rank correlation coefficient . numbers of swelled and painful joints were significantly correlated with cal > 3 , pd > 4 and bop . the results of pearson 's correlation coefficient in evaluation of the correlation between different variables in ra patients the mean age of adolescent controls was 13.4  1.55 years . this rate in patients with jia was 13.43  1.45 years . except for bop that was significantly higher in jia patients than controls ( p < 0.001 ) , no significant differences were observed between the two groups in terms of pd , cal , sites with cal > 3 and pi [ table 3 ] . comparison of periodontal parameters in control and jia patients 
 table 4 demonstrates significant and insignificant correlations between understudy variables in jia patients using pearson 's correlation coefficient . the results of pearson 's correlation coefficient in evaluation of the correlation between different variables in jia patients in this study , periodontal parameters including pd , cal , percentage of sites with pd > 4 mm , percentage of sites with cal > 3 mm , percentage of sites with bop and pi index were significantly higher in ra patients than controls . in this group , direct and significant correlations were found between serologic findings , disease severity and number of painful and inflamed joints with periodontal factors . in jia patients , no significant differences were detected between the two groups regarding periodontal parameters with the exception of bop , which was significantly higher in cases . in this group , no significant correlations were found between jia findings and periodontal parameters . higher and different pi and pd scores can be a reason for the difference . in reichert et al . study , although pi and mean percentage of sites with cal > 3.5 were higher in jia group , there was no difference between patients and controls in number of people having at least one site with cal.3.5 , which was considered as periodontitis . in this study , even though we found that periodontal factors were significantly different between ra and healthy controls , but this difference might be somehow as a result of the difference in pi between two groups . we knew that all confounding factors such as pi are better to be matched between case and control groups , but it needs a large number of patients in each group , which is a difficult challenge for studies to have sufficient numbers of the samples , especially jir patients . periodontal disease usually has a chronic entity that needs some time to be identified by routine clinical examination , and lower ages of jia patients might inhibit enough time for the presentation of this time elapsing disease . prevalence and severity of periodontal diseases in juvenile ages are low , and few cases of aggressive periodontal diseases could be seen in these periods of ages . there was no significant difference between cal in jia group and healthy controls in this study . in adults , although the difference between cal exists between two groups , but our limitation in patient number did not allow us to match the groups by determining a cutoff point or use multivariate tests . the present study is one of the few studies that evaluated the periodontal condition in both ra and jia patients , and as far as we know , it is the only one in iran evaluating this relation in jia patients . radiographic examination was not performed in this study , and most of jia patients were in their mixed dentition period . considering the possibility of localized aggressive periodontitis in the age range of 14 - 17 in jia patients , we could not exactly recognize this disease and discriminate it from chronic periodontitis . due to low prevalence of aggressive types of periodontal diseases , there are few chances to find any possible relationships between aggressive periodontitis and arthritis especially juvenile type of the disease . there are few , if any , studies evaluating relationships between aggressive periodontitis and jia and the rationale of this relationship is yet to be cleared . on the other hand , considering both aggressive and chronic periodontitis in the relation between periodontitis and rheumatoid arthritis may probably show different results . considering the difference between immunologic and pathologic nature of these two types of periodontitis might be helpful in future studies . as it was mentioned before , in evaluating the relationship between periodontal disease and rheumatoid arthritis , the role of cytokines and inflammatory mediators should be considered . in ra and jia all these inflammatory factors have been reported in aggressive periodontitis and are related to disease severity and specific periodontal pathogens . some authors found a slight increase in th1 cytokine such as il-2 and ifn in destructed periodontal tissues . since some studies suggest that , t - cell characteristics are the same in some respects in ra or jia and periodontal disease more investigation in this relation is needed . another pathogenic relation that needs more consideration is neutrophils role in the pathogenesis of both diseases and impaired neutrophilic response in ra or jia and periodontal disease . some studies have considered the role of genetic components in the susceptibility to both diseases . hla subtypes and genes that are not in the hla region association may contribute to the relationship between ra or jia and periodontal disease . periodontal parameters including pd and cal were significantly higher in ra patients than controls with direct and significant correlations between serologic findings , disease severity and number of painful and inflamed joints . in jia patients , no significant differences were detected between the two groups regarding periodontal parameters except bop and no significant correlations were found between jia findings and periodontal parameters . specifically , longitudinal multi center studies are necessary to consider confounding factors including stress , nutritional factors and lifestyle and their correlation with periodontitis and ra at the same time . last but not least , a close cooperation between dentists and rheumatologists is required to improve patient status . the authors of this manuscript declare that they have no conflicts of interest , real or perceived , financial or non - financial in this article . the authors of this manuscript declare that they have no conflicts of interest , real or perceived , financial or non - financial in this article .
background : rheumatoid arthritis ( ra ) is the most prevalent chronic inflammatory disease of the joints . 
 it is correlated with periodontal disease due to similar factors that exist in both diseases . 
 the present study assessed the relationship of periodontal disease with ra and juvenile idiopathic arthritis ( jia).materials and methods : in this case - control study , 30 ra and 30 jia patients along with similar number of matched controls were selected among patients referred to imam khomeini hospital , tehran , iran . 
 periodontal parameters including pocket depth ( pd ) , clinical attachment level ( cal ) , oleary and bay plaque index ( pi ) and bleeding on probing ( bop ) were determined in cases and controls . 
 erythrocyte sedimentation rate , number of painful and inflamed joints and severity of disease were evaluated in ra and jia patients . 
 mann - whitney u - test nonparametric , spearman and pearson 's correlation coefficients , and chi - square tests were used as statistical analysis (  = 0.05).results : pd ( 4.17 vs. 3.6 mm ; p < 0.0001 ) , cal ( 4.89 vs. 4.18 mm ; p < 0.002 ) , percentage of sites with pd > 4 mm ( 58.83% vs. 44.33% ; p < 0.002 ) , percentage of sites with cal > 3 mm ( 74.13% vs. 64.4% ; p < 0.001 ) , percentage of sites with bop ( 9.67% vs. 6.87% ; p < 0.0001 ) and pi index ( 85.73% vs. 80.63% ; p < 
 0.0001 ) were significantly higher in ra patients than controls . in this group 
 , direct and significant correlations were found between serologic findings , disease severity and number of painful and inflamed joints with periodontal factors . in jia patients , no significant relationships were found between jia findings and periodontal parameters.conclusion:considering the limitations of this study , there was a relationship between ra and periodontal disease . 
 severity of periodontal disease increases in patients with ra , while no increased risk of periodontal disease or its severity was observed among jia patients .