***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The aim of this study was to compare changes in periodontal status in a Swedish population over a period of 20 years . Cross-sectional studies were carried out in Jönköping County in 1973 , 1983 , and 1993 . Individuals were r and omly selected from the following age groups : 20 , 30 , 40 , 50 , 60 , and 70 years . A total of 600 individuals were examined in 1973 , 597 in 1983 , and 584 in 1993 . The number of dentate individuals was 537 in 1973 , 550 in 1983 , and 552 in 1993 . Based on clinical data and full mouth intra-oral radiographs , all individuals were classified into 5 groups according to the severity of the periodontal disease experience . Individuals were classified as having a healthy periodontium ( group 1 ) , gingivitis without signs of alveolar bone loss ( group 2 ) , moderate alveolar bone loss not exceeding 1/3 of the normal alveolar bone height ( group 3 ) , severe alveolar bone loss ranging between 1/3 and 2/3 of the normal alveolar bone height ( group 4 ) , or alveolar bone loss exceeding 2/3 of the normal bone height and angular bony defects and /or furcation defects ( group 5 ) . During these 20 years , the number of individuals in groups 1 and 2 increased from 49 % in 1973 to 60 % in 1993 . In addition , there was a decrease in the number of individuals in group 3 , the group with moderate periodontal bone loss . Groups 4 and 5 comprised 13 % of the population and showed no change in general between 1983 and 1993 . The individuals comprising these groups in 1993 , however , had more teeth than those who comprised these groups in 1983 ; on the average , the individuals in disease group 4 had 4 more teeth and those in disease group 5 , 2 more teeth per subject . In 1973 , these 2 groups were considerably smaller , probably because of wider indications for tooth extraction s and fewer possibilities for periodontal care which meant that many of these individuals had become edentulous and were not placed in a group . Individuals in groups 3 , 4 , and 5 were subdivided according to the number of surfaces ( % ) with gingivitis and periodontal pockets ( > or = 4 mm ) . In 1993 , 20 % , 42 % . and 67 % of the individuals in groups 3 , 4 , and 5 respectively were classified as diseased and in need of periodontal therapy with > 20 % bleeding sites and > 10 % sites with periodontal pockets > or = 4 mm . In conclusion , an increase in the number of individuals with no marginal bone loss and a decrease in the number of individuals with moderate alveolar bone loss can be seen . The prevalence of individuals in the severe periodontal disease groups ( 4 , 5 ) was unchanged during the last 10 years ; however , the number of teeth per subject increased BACKGROUND One hypothesis to explain the association between periodontal disease ( PD ) preterm/low birth weight ( PT/LBW ) is that PT/LBW may be indirectly mediated through translocation of bacteria or bacterial products in the systemic circulation . Transient bacteremias occur in subjects with marginal periodontitis or with gingivitis , and it is possible that bacteria and their products may reach the placental membranes hematogenously and provide the inflammatory effect to induce preterm labor . The effect of gingivitis as a potential risk factor for PT/LBW has still not been studied . A r and omized controlled trial was undertaken to determine the effect of routine plaque control and scaling on the pregnancy outcomes in women with gingivitis . METHODS Eight hundred seventy ( 870 ) pregnant women with gingivitis , aged 18 to 42 , were enrolled while receiving prenatal care in Santiago , Chile . Women were r and omly assigned in a two-to-one fashion to either a treatment group ( N = 580 ) , receiving periodontal treatment before 28 weeks of gestation or to a control group ( N = 290 ) , receiving periodontal treatment after delivery . Periodontal therapy consisted of plaque control , scaling , and daily rinsing with 0.12 % clorhexidine . Maintenance therapy was provided every 2 to 3 weeks until delivery , and consisted of oral hygiene instruction and supragingival plaque removal by instrumentation , as needed . The primary outcomes assessed were delivery at less than 37 weeks of gestation or an infant weighing less than 2,500 g. RESULTS Of the 870 women enrolled , 36 women ( 27 in the treatment group and nine in the control group ) were excluded from the analyses for different reasons . The incidence of PT/LBW in the treatment group was 2.14 % ( 12/560 ) and in the control group , 6.71 % ( 19/283 ) ( odds ratio [ OR ] 3.26 ; 95 % confidence interval [ CI ] 1.56 to 6.83 ; P = 0.0009 ) . Multivariate logistic regression analysis showed that , after adjusting for several known risk factors for PT/LBW , women with gingivitis were at a higher risk of PT/LBW than women who received periodontal treatment ( OR 2.76 ; 95%CI 1.29 to 5.88 ; P = 0.008 ) . CONCLUSIONS Periodontal treatment significantly reduced the PT/LBW rate in this population of women with pregnancy-associated gingivitis . Within the limitions of this study , we conclude that gingivitis appears to be an independent risk factor for PT/LBW for this population Periodontitis has been associated with  adverse pregnancy outcomes .  Results from intervention studies are few and controversial . The present study assessed the effects of non-surgical periodontal treatment in the occurrence of adverse pregnancy outcomes .  Two hundred forty-six eligible women were r and omly divided into two groups : periodontitis intervention ( n = 122 ; undergoing non-surgical treatment during gestation ) and periodontitis control ( n = 124 ; not treated during gestation ) . Univariate analysis was performed and estimates of relative risk were reported . Data from 225 women were analyzed . No differences for preterm birth ( p = 0.721 ) , low birth weight ( p = 0.198 ) , and preterm low birth weight ( p = 0.732 ) rates were observed . Relative risk estimates for preterm birth , low birth weight , and preterm low birth weight in the periodontitis intervention group were 0.915 ( 95 % CI 0.561–1.493 ) , 0.735 ( 95 % CI 0.459–1.179 ) , and 0.927 ( 0.601–1.431 ) , respectively . Non-surgical periodontal treatment during the second semester of gestation did not reduce the risk for preterm birth , low birth weight , and preterm low birth weight Considering the high prevalence of preterm birth ( PTB ) and low birth weight ( LBW ) and their complications as well as the role played by periodontal disease in their incidence and the lack of any report of periodontal therapy on these problems in Iran , the goal of the present research was to determine the effects of periodontal treatment on PLBW incidence among women with moderate or advanced periodontitis who were referred to Javaheri hospital ( 2004 - 2005 ) . This clinical trial research was conducted on 30 pregnant women age ranging from 18 - 35 years old , with moderate or advanced periodontitis . Fifteen subjects r and omly underwent the first phase of periodontal treatment including scaling , root planning and the use of 0.2 % chlorhexidine mouth rinse for one week . None of these steps were taken for the controls . After necessary follow ups , the effect of periodontal treatment on birth term and birth weight were analyzed statistically . This research was conducted on 30 subjects , 15 controls and 15 cases in study group . In the control group , the observed rate of PLBW was 26.7 % whereas among periodontally treated group , phase I , PLBW infant was not observed ( P < 0.05 ) . Infants birth weight were ( 3059.3 - 389.7 ) gms in study group and ( 3371 - 394.2 ) gms in the control group and respectively ( P < 0.05 ) . Periodontal therapy , phase I , results in a reduction in PLBW incidence rate . Therefore , the application of such a simple method among periodontally diseased pregnant women is recommended BACKGROUND Few studies have examined the potential effects of  periodontal treatment during pregnancy on  pregnancy outcomes , periodontal status , and inflammatory biomarkers . METHODS A r and omized , delayed-treatment , controlled pilot trial was conducted to evaluate the effects of second-trimester scaling and root planing and the use of a sonic toothbrush on the rate of preterm delivery ( < 37 weeks gestation ) . Secondary outcome measures included changes in periodontal status , levels of eight oral pathogens , levels of gingival crevicular fluid ( GCF ) interleukin-1beta ( IL-1beta ) , prostagl and in E(2 ) ( PGE(2 ) ) , 8-isoprostane ( 8-iso ) , and IL-6 , and serum levels of IL-6 , soluble intercellular adhesion molecule 1 ( sICAM1 ) , 8-isoprostane , soluble glycoprotein 130 ( sGP130 ) , IL-6 soluble receptor ( IL-6sr ) , and C-reactive protein ( CRP ) . Logistic regression models were used to test for effects of treatment on preterm delivery . Secondary outcomes were analyzed by analysis of covariance adjusting for subject baseline values . RESULTS Periodontal intervention result ed in a significantly decreased incidence odds ratio ( OR ) for preterm delivery ( OR = 0.26 ; 95 % confidence interval = 0.08 to 0.85 ) , adjusting for baseline periodontal status which was unbalanced after r and omization . Pregnancy without periodontal treatment was associated with significant increases in probing depths , plaque scores , GCF IL-1beta , and GCF IL-6 levels . Intervention result ed in significant improvements in clinical status ( attachment level , probing depth , plaque , gingivitis , and bleeding on probing scores ) and significant decreases in levels of Prevotella nigrescens and Prevotella intermedia , serum IL-6sr , and GCF IL-1beta . CONCLUSIONS Results from this pilot study ( 67 subjects ) provide further evidence supporting the potential benefits of periodontal treatment on pregnancy outcomes . Treatment was safe , improved periodontal health , and prevented periodontal disease progression . Preliminary data show a 3.8-fold reduction in the rate of preterm delivery , a decrease in periodontal pathogen load , and a decrease in both GCF IL-1beta and serum markers of IL-6 response . However , further studies will be needed to substantiate these early findings BACKGROUND A recent clinical trial ( Obstetrics and Periodontal Therapy [ OPT ] Study ) demonstrated that periodontal therapy during pregnancy improved periodontal outcomes but failed to impact preterm birth . The present study evaluated seven target bacteria , Aggregatibacter actinomycetemcomitans ( previously Actinobacillus actinomycetemcomitans ) , Porphyromonas gingivalis , Treponema denticola , Tannerella forsythia ( previously T. forsythensis ) , Prevotella intermedia , Campylobacter rectus , and Fusobacterium nucleatum , in subgingival dental plaque of pregnant women in the OPT Study and their association with birth outcomes . METHODS Pregnant women were r and omly assigned to receive periodontal treatment before 21 weeks ' gestation or after delivery . Subgingival plaque was sample d at baseline ( 13 to 16 weeks ; 6 days of gestation ) and at 29 to 32 weeks . We analyzed subgingival plaque sample s from women who experienced fetal loss , delivered a live preterm infant ( preterm women ) , or delivered a full-term infant ( full-term women ) . Sample s were analyzed using quantitative polymerase chain reaction . Associations between preterm birth and bacterial counts and percentages were tested using multiple linear regression . RESULTS No significant differences were observed at baseline between preterm and full-term women for any measured bacterial species or group of species , after accounting for multiple comparisons . Changes in bacterial counts and proportions during pregnancy also were not associated with birth outcomes . In full-term and preterm women , periodontal therapy significantly reduced ( P < 0.01 ) counts of all target species except for A. actinomycetemcomitans . CONCLUSIONS In pregnant women with periodontitis , non-surgical periodontal therapy significantly reduced levels of periodontal pathogens . Baseline levels of selected periodontal pathogens or changes in these bacteria result ing from therapy were not associated with preterm birth BACKGROUND  Preterm low birth weight was reported to be related to periodontal infections that might influence the fetus-placenta complex . The aim of this study was to provide periodontal treatment for pregnant women and to evaluate if this treatment can interfere with pregnancy duration and weight of the newborn . METHODS The sample consisted of 450 pregnant women who were under prenatal care at a polyclinic in Três Corações , Brazil . Women with risk factors , such as systemic alterations ( ischemic cardiopathy , hypertension , tuberculosis , di 
    Output:
    
Meta- analysis using this methodology concluded that there is no benefit for periodontal treatment to reduce complications of pregnancy .