牙周病与早产低出生体重儿关系的临床研究

目的比较分娩早产低出生体重儿(PLBW)的孕妇与足月妊娠正常分娩新生儿(NBW)孕妇的牙周状况及牙周病的发生率,探讨牙周病与PLBW的关系。方法随机选取分娩PLBW的孕妇206例为研究组,选取同期分娩NBW的孕妇209例为对照组,检测两组孕妇的牙周状况,记录菌斑指数(PLI)、探诊深度(PD),临床附着丧失(CAL)和出血指数(BI),并计算牙周炎位点率(PD>3 mm,CAL>2 mm)及牙周病的发生率。结果分娩早产低出生体重儿的孕妇牙周炎位点率(3.3%)和牙周病发生率(81.1%)明显高于对照组(1.4%,35.9%),差异有显著性(P<0.01);牙周炎位点率与孕周和新生儿体重均呈负相关系(P<0.05)。结论牙周病可能是PLBW发生的危险因素。     

牙周状况、血清白细胞介素-1β水平与妊娠关系初探

目的探讨牙周状况、血清白细胞介素- 1β（IL- 1β）水平与妊娠间的关系。方法以40例先兆早产孕妇（TPL组）和40例正常孕妇（Non- TPL组）为研究对象，检查全口牙齿的牙周状况，记录菌斑指数（PLI）、探诊深度、临床附着丧失和出血指数（BI），并计算牙周炎位点率。酶联免疫吸附试验检测血清IL- 1β水平。对各项检查指标进行统计分析。结果①TPL组40例孕妇中26例足月产（TPL- TB小组），14例早产（TPL- PB小组）；Non- TPL组40例孕妇皆足月产。TPL组和Non- TPL组、TPL- TB小组和TPL- PB小组的分娩孕周、新生儿出生体重、PLI、牙周炎位点率和血清IL- 1β水平间的差异均有统计学意义（P<0.05）。②分娩孕周和牙周炎位点率、BI、IL- 1β水平呈负相关（P<0.05），IL- 1β水平与牙周炎位点率和BI呈正相关（P<0.05）。结论牙周感染可能是早产的原因之一。     

牙龈卟啉单胞菌PG0717基因与慢性牙周炎的相关性研究

目的检测慢性牙周炎患者和牙周健康者龈下菌斑中牙龈卟啉单胞菌（P.gingivalis）PG0717基因,探讨PG0717基因与牙周临床指数之间的关系。方法选取慢性牙周炎（CP）患者90例和牙周健康者90例,共采集龈下菌斑标本540个;记录临床牙周指数（牙周探诊深度、临床附着丧失和探诊出血）;设计特异性引物检测P.gingivalis阳性龈下菌斑标本的PG0717基因。结果在P.gingivalis阳性龈下菌斑中,CP组PG0717基因检出率显著高于对照组,分别为56.22%和41.27%（掊2=4.50,P＜0.05）;随着牙周探诊深度、临床附着丧失加重和探诊出血趋势的增加,CP组该基因检出率呈现增高趋势。结论PG0717基因与P.gingivalis的致病性有关。     

成人正畸患者龈下菌斑中牙龈卟啉单胞菌的变化

目的研究成人正畸患者在固定矫治器戴入后,其牙周临床指标和龈下菌斑中牙龈卟啉单胞菌（P.gingivalis）的早期变化。方法选择成人正畸患者11例,分别在矫治器戴入前,戴入后第1、3个月检查牙周临床指标（包括菌斑指数、龈沟出血指数、探诊深度和附着丧失）,同时采集龈下菌斑样本,利用荧光实时定量聚合酶链反应检测样本中P.gingivalis和总细菌的数量,计算出P.gingivalis的检出率和构成比。分析牙周临床指标和P.gingivalis的检出率、构成比在不同观察时点的变化情况。结果菌斑指数、龈沟出血指数在矫治器戴入后均比戴入前明显升高（P<0.05）。探诊深度在矫治器戴入1个月后升高（P<0.05）,3个月后下降至基线水平。试验中未发现有探诊深度大于2 mm的患者,也未发现有附着丧失的患者。在3次检测中,P.gingivalis检出率均为45.5%,而P.gingivalis构成比的变化也无统计学差异（P>0.05）。结论固定矫治器戴入早期可引发成人正畸患者口内局部菌斑堆积,菌群中P.gingivalis增殖,出现轻度牙龈炎。     

牙周病与早产低体重儿的关系及其机制的研究进展

早产是指新生儿出生时胎龄未满37周,低体重儿是指新生儿出生时体重未满2 500 g,早产常伴发低体重儿。早产被认为是新生儿死亡的主要原因。牙周病是一种口腔常见的慢性感染性疾病,与全身多种系统性疾病具有相关性。流行病学资料表明牙周病与早产低体重儿具有一定相关性,牙周病是早产低体重儿等不良妊娠结局的危险因素之一,可能的机制包括牙周致病菌菌体的直接作用,引起机体炎症反应和过激免疫反应等,然而具体的机制尚未明确。本文就牙周病与早产低体重儿的相关性,开展牙周治疗对早产低体重儿发生率的影响,以及牙周病引发早产低体重儿的相关机制作一综述。     

孕妇牙周炎与低出生体重儿相关性研究

目的探讨孕妇牙周炎与低出生体重儿的关系。方法以产妇为目标人群,选取304例生育低出生体重儿的产妇为病例组,611例新生儿体重大于或等于2500g的产妇为对照组,进行病例对照研究。分娩后1周内对产妇进行牙周检查,使用封闭式调查表进行问卷调查,对所得数据进行回归分析。结果病例组和对照组的牙周炎患病率相似,分别为58.5%和54.5%,2组的牙周状况差异无统计学意义（χ^2=3.58,P=0.20）。患有牙周炎的产妇生产低出生体重儿的似然比（oddsratio,OR）为1.18,二者具有相关性,但这种相关性无统计学意义（P=0.21）。调整了妊娠年龄、妊娠史、产前保健质量、吸烟、低出生体重儿既往史、早产儿既往史、高血压、子痫前期、孕期体重变化9项混杂因素后,孕妇牙周炎与低出生体重儿没有统计学意义的相关性,OR为0.93,95%可信区间为0.63～1.41,P=0.97。结论适当控制混杂因素后,孕妇牙周炎与低出生体重儿没有统计学意义的相关性。     

成人牙周健康状况与fimA基因型牙龈卟啉单胞菌的相关性

目的分析不同fimA基因型牙龈卟啉单胞菌（P.gingivalis）在牙周健康人群和慢性牙周炎人群中的分布,探讨不同fimA基因型P.gingivalis与成人牙周状况的相关关系。方法收集牙周健康组（136例）和慢性牙周炎组（115例）的龈下菌斑样本,采用16S rRNA PCR法检测P.gingivalis,并根据各fimA基因型（Ⅰ～Ⅴ和Ⅰb）的特异性引物检测不同fimA基因型P.gingivalis菌株的分布,计算OR值和95%可信区间。结果牙周健康组和慢性牙周炎组龈下菌斑样本中P.gingivalis阳性率分别为22.1%和81.7%,多数样本中只检测到1种fimA基因型。牙周健康组中ⅠfimA型的检出率最高（占66.7%）;慢性牙周炎组中则为ⅡfimA基因型（占43.6%）,其次为Ⅳ和Ⅰb fimA基因型。慢性牙周炎的发生与P.gingivalis的关系密切（OR=16.36）,Ⅰ、Ⅰb、Ⅱ、Ⅲ、Ⅳ、ⅤfimA基因型P.gingivalis与慢性牙周炎相关性的OR值分别为0.97、13.26、36.62、4.57、22.86、1.19;ⅡfimA基因型P.gingivalis与慢性牙周炎的相关性最强,其次为Ⅳ和Ⅰb型。结论P.gingivalis菌株的fimA基因型存在差异,特异性fimA基因型P.gingivalis可能与成人慢性牙周炎的发生关系密切。     

200例早产低体重儿母体牙周健康状况的调查分析

在上世纪90年代，Offenbacher等提出假说，认为牙周感染可能是妊娠不良结局的危险因素之一…，国外研究在动物实验、流行病学及部分人群的前瞻性研究中都表明母体牙周病和早产低体重儿有关口，牙周病和早产低体重儿的关系在国外已成为研究的热点之一。而我国是牙周疾病的高发国家之一，母体牙周病与早产之间的关系尚刚起步，本研究对元明显诱因的早产低体重儿的母亲及正常足月儿的母亲的牙周健康状况进行问卷调查。从而为进一步探讨我国早产低体重儿和母亲牙周状况的关系提供依据。     

青春期龈炎龈下菌斑中牙龈卟啉单胞菌kgp基因型的研究

目的 研究青春期龈炎龈下菌斑中牙龈卟啉单胞菌（P.gingivalis）的特异kgp基因型，评估其与疾病严重程度之间的关系。方法检查并记录青春期龈炎组与牙龈健康组各36例的牙周临床指数，收集龈下菌斑样本，提取染色体DNA，采用聚合酶链反应（PCR）方法扩增编码牙龈蛋白酶K（KGP）催化域的序列片段。PCR产物用限制性内切酶Mse I消化。结果 P.gingivalis有毒株W83表现为kgp-A型，而无毒株ATCC33277表现为kgp-B型。所有P.gingivalis阳性个体的龈下菌斑中只检测到一种kgp基因型。kgp-A型在青春期龈炎组P．gingivalis阳性个体中的检出率为79．0％，在牙龈健康组为22．2％，两组kgp基因型的检出率差异有统计学意义（P=0．028）；青春期龈炎组有P.gingivalis定植的个体中，牙周临床指数与kgp的基因型无相关关系（P〉0．05）。结论青春期龈炎个体定植的Pgingivalis的kgp基因型多与有毒株P.gingivalis W83的表现相同，有必要监测kgp-A型阳性的个体，因其个体发展为牙周疾病的危险度可能会增高。     

牙龈卟啉单胞菌PG0839基因对小鼠肝细胞和血清中IL-1β与IL-6表达影响研究

目的 探讨牙龈卟啉单胞菌（Porphyromonas gingivalis,P.gingivalis）PG0839基因对小鼠肝细胞和血清中炎症因子白细胞介素1β（IL-1β）与白细胞介素6（IL-6）表达的影响,以期为进一步明确该基因的功能提供实验依据。方法 本研究于2013年6—12月在中国医科大学口腔医学院中心实验室完成。选择18～22 g SPF级昆明小鼠18只,适应性喂养1周后,随机分为3组,每组6只。组1为接种P.gingivalis W83菌株组,组2为接种P.gingivalis PG0839基因突变菌株组,组3为对照组。在组1、组2的每只小鼠背部皮下2个位点各注射浓度为1×109 CFU/mL的细菌悬液0.1 mL,组3的每只小鼠注射等量无菌PBS缓冲液。在细菌接种后5 d处死各组小鼠,留存肝组织及血清。使用双抗体夹心酶联免疫吸附（ELISA）法检测各组小鼠肝组织和血清中IL-1β与IL-6水平。应用SPSS 13.0统计软件对结果数据进行分析。结果 组2小鼠肝组织和血清中的IL-1β与IL-6表达显著低于组1小鼠（P＜0.05）;与组3小鼠相比,组1和组2小鼠肝组织和血清中IL-1β与IL-6表达均显著增加（ P < 0. 05）。结论 PG0839基因可能参与P.gingivalis引发小鼠全身炎症的过程。     

北京地区母亲牙周状况与早产低出生体重新生儿的关系

目的 初步评价北京地区人群中母亲牙周状况与早产低出生体重新生儿的关系.方法 对2004年1月至2005年12月在北京市4家医院分娩的83例早产低体重新生儿(preterm low birth weight,PLBW)的母亲(PLBW组)以及44名正常新生儿(normal birth weight,NBW)的母亲(NBW组)进行牙周临床指标的检查.所有受检者均全身健康.检查指标包括:菌斑指数(plaque index,PLI)、探诊深度(probing depth,PD)、临床附着丧失(attachment loss,AL)和出血指数(bleeding index,BI).结果 中度慢性牙周炎及侵袭性牙周炎母亲发生PLBW的风险是牙龈炎或轻度慢性牙周炎母亲的4.26倍.PLBW组与NBW组PD≥4 mm位点率(分别为8.1%和6.9%)、AL≥2 mm 位点率(分别为12.8%和6.1%)和BOP(+)位点率(分别为70.4%和66.9%),PLBW组均显著高于NBW组(P值分别小于0.01、0.001、0.01).结论 本组人群中母亲的牙周状况与PLBW之间可能存在关联,较差的牙周状况可能是发生PLBW的危险因素之一.     

The secretion of prostaglandin E2 and interleukin 1-beta in women with periodontal diseases and preterm low-birth-weight

Prematurity is of one of the main causes of neonatal morbidity and mortality. Clinical observations show, that periodontitis in pregnant women can be a direct risk factor for preterm labor, with a greater influence rate compared to other risk factors. The aim of the study was to asses the relationship between periodontal diseases and PLBW in the population of women from the Lower Silesian Region (Poland), and the evaluation of prostaglandin E2 (PGE2), interleukin-1 beta (IL-1 beta) levels in gingival cervicular (GCF) and blood serum in women with PLBW and women giving birth on time as well as secretion of these proinflammatory mediators in whole blood after bacterial lipopolysaccharide stimulation. The study group consisted of 84 women with PLBW (39.2% primiparous), aged 17-41 (mean 27.57). The controls were 44 women (47.7% primiparous) aged 16-38 (mean 26.36) who gave birth on time to a normal birthweight baby. PGE2 and IL-1 beta concentrations in serum and GCF were determined by means of immunoenzymatic method (EIA). In the studied population women over 28 years and exposed to medical risk factors had more frequent PLBW occurrence probability. In primiparous over 28 there is 4 times greater probability of preterm labor, and in case of the severe and generalized periodontitis presence there is 3.9 times higher possibility of PLBW compared to women with healthy periodontium. In all women with PLBW there is a significantly higher PGE2 and IL-1 beta concentration in GCF, and in primiparous also PGE2 level in blood serum, compared to controls.     

Periodontal infections and pre-term low birth weight: a case-control study

OBJECTIVE: Pre-term delivery of low-birth-weight infants [pre-term low birth weight (PLBW)] remains a significant public health issue and a major cause of neonatal death and long-term health problems. There is a growing consensus that infections remote from fetal-placental unit may influence PLBW infants. Recent studies have suggested that maternal periodontal disease may be an independent risk factor for PLBW. The purpose of the present study was to evaluate the possible link between periodontal infections and PLBW by means of clinical and microbiological data in post-partum women with low socioeconomic level. METHODS: Clinical periodontal recordings comprising dental plaque, bleeding on probing, probing pocket depth and gingival recession were performed (six sites/tooth) in a total number of 181 women (53 cases and 128 controls) within 3 days post-partum. Subgingival plaque samples from mesio-or disto-buccal aspect of randomly selected one first molar and one incisor tooth have been obtained by paperpoints and were analysed by checkerboard DNA-DNA hybridization with respect to 12 bacterial species. In all analyses, the individual subject was the computational unit. Thus, mean values for all clinical parameters were calculated and bacterial scores from each individual sample were averaged. Statistical methods included Student's t-test, Fisher's exact test/chi(2) test, and multiple logistic regression analysis. RESULTS: The cases have gained significantly less weight during the pregnancy than did the controls (p<0.05). There were no statistically significant differences between the cases and controls with regard to the dental and periodontal parameters and the values of clinical periodontal recordings were found to be very similar (p>0.05). Mean and median scores (bacterial loads) of Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Actinobacillus actinomycetemcomitans, and Streptococcus intermedius in the subgingival plaque sampling sites were significantly higher in the controls than in the cases (p<0.05). The occurrence rates of P. intermedia, Fusobacterium nucleatum, Peptostreptococcus micros, Campylobacter rectus, Eikenella corrodens, Selenomonas noxia and S. intermedius were higher in the cases compared with the controls, but the differences were not statistically significant (p>0.05). According to the model created by the multiple logistic regression analysis, P. micros and C. rectus were found to significantly increase the risk of PLBW (p<0.01 and p<0.05 respectively), while P. nigrescens and A. actinomycetemcomitans decreased this risk (p<0.01). CONCLUSION: The present findings indicated that when subgingival bacteria were evaluated together, P. micros and C. rectus may have a role in increasing the risk for PLBW, although no single bacteria exhibited any relation with the risk of PLBW. Further studies are required to better clarify the possible relationship between periodontal diseases and PLBW.     

Periodontal infections and pre-term birth: early findings from a cohort of young minority women in New York

The aim of this report is to provide early data from an ongoing study examining (i) the relationship between periodontal infections and pre-term low birth weight (PLBW) in a cohort of young, minority, pregnant and post-partum women; and (ii) the effect of periodontal interventions on pregnancy outcome. During the first 2 yr of the study, 213 women were enrolled and examined clinically for dental plaque, calculus, bleeding on probing, and probing depth. Birth outcome data were available for 164 women, including one group (n = 74) subjected to oral prophylaxis during pregnancy, and a second group (n=90) who received no prenatal periodontal treatment. Subgingival plaque samples were available from 145 subjects (4 samples/subject) and were analyzed by checkerboard DNA hybridization with respect to 12 bacterial species. The prevalence of PLBW was 16.5% (27 cases) in this cohort. No differences in clinical periodontal status were observed between PLBW cases and women with normal birth outcome. However, PLBW mothers had significantly higher levels of Bacteroides forsythus and Campylobacter rectus, and consistently elevated counts for the other species examined. PLBW occurred in 18.9% of the women who did not receive periodontal intervention (17 cases), and in 13.5% (10 cases) of those who received such therapy.     

母体唾液及龈沟液细胞因子水平与早产低体重新生儿关系的病例对照研究

目的 验证牙周炎是否为早产低体重新生儿(preterm low birth weight,PLBW)母亲体内低度炎症的来源之一,初步探讨PLBW与炎症因子之间的关系.方法 以83例PLBW的母亲(PLBW组)及44名健康新生儿(normal birth weight,NBW)的母亲(NBW组)为研究对象,留取受试对象的静息全唾液、龈沟液,应用酶联免疫吸附试验检测唾液和龈沟液中白细胞介素(IL)-1β和IL-6水平,比较两组间唾液和龈沟液中细胞因子水平的差异,并分析细胞因子与分娩孕周、新生儿体重之间的相关性.结果 唾液IL-1β水平在PLBW组[(78.32±11.81)ng/L]显著高于NBW组[(39.66±11.89)ng/L],差异有统计学意义(P<0.05);分娩孕周与唾液IL-6之间呈显著的负相关关系(r=-0.274,P<0.01);新生儿体重与龈沟液IL-1β(r=-0.231,P<0.01)、唾液IL-6(r=-0.424,P<0.01)之间呈显著的负相关关系.结论 唾液和龈沟液中炎性因子水平越高,分娩孕周越短、新生儿体重越轻,母体牙周炎程度与PLBW之间可能存在一定程度的相关关系.     

Influence of combinations of bacteria on the levels of prostaglandin E2, interleukin-1beta, and granulocyte elastase in gingival crevicular fluid and on the severity of periodontal disease

BACKGROUND: The aim of this study was to investigate the simultaneous presence of periodontal microbiota on inflammatory markers in gingival crevicular fluid from individuals with periodontal diseases. METHODS: A total of 82 individuals with periodontal disease (mean age: 54.3 +/- 3.0 years) and 31 periodontally healthy individuals (mean age: 53.2 +/- 3.0 years) were randomly chosen and underwent clinical oral examinations in 2003 with the determination of the dental plaque index (PI), gingival index (GI), and periodontal probing depth (PD). The simultaneous presence of polymerase chain reaction (PCR)-assessed periodontal bacteria, levels of prostaglandin E(2) (PGE(2)), granulocyte elastase, interleukin 1-beta (IL-1beta), and total protein concentration were determined from the pockets. Marginal bone height percent was measured on x-rays. Analysis of variance and chi(2) tests were used to analyze the results. RESULTS: In sites with Tannerella forsythensis, levels of PGE(2) (pg/site), granulocyte elastase (monoclonal antibodies (mAbs)/site), and total protein (mg/ml) were significantly higher than in sites without T. forsythensis (P <0.05, P <0.01, and P <0.05, respectively). Those with periodontal disease with simultaneous presence of T. forsythensis and Porphyromonas gingivalis, or T. forsythensis and Prevotella nigrescens, showed significantly higher PI and GI, deeper PD, more loss of attachment, and more release of PGE(2) and granulocyte elastase than did periodontitis patients without these bacteria. CONCLUSION: The simultaneous presence of T. forsythensis and P. gingivalis, or T. forsythensis and P. nigrescens, seemed to promote the release of subgingival inflammatory mediators and seemed to be associated with more severe periodontal disease.     

Periodontal bacterial profiles in pregnant women: response to treatment and associations with birth outcomes in the obstetrics and periodontal therapy (OPT) study

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 randomly assigned to receive periodontal treatment before 21 weeks' gestation or after delivery. Subgingival plaque was sampled at baseline (13 to 16 weeks; 6 days of gestation) and at 29 to 32 weeks. We analyzed subgingival plaque samples from women who experienced fetal loss, delivered a live preterm infant (preterm women), or delivered a full-term infant (full-term women). Samples 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 resulting from therapy were not associated with preterm birth.     

Detection of Porphyromonas gingivalis in the amniotic fluid in pregnant women with a diagnosis of threatened premature labor

BACKGROUND: Epidemiologic and randomized controlled studies have shown that periodontal diseases may be associated with preterm labor and delivery of infants with low birth weights. The purpose of the present study was to determine the presence of microbial invasion of the amniotic cavity by periodontopathic bacteria in pregnant women with a diagnosis of threatened premature labor. METHODS: A periodontal examination and collection of amniotic fluid and subgingival plaque samples were performed on women identified as having threatened premature labor (preterm premature rupture of membranes without clinical infection or labor and preterm labor with intact membranes) and a gestational age ranging between 24 and 34 weeks. Samples collected from amniotic fluid and from the four deepest periodontal pockets in each patient were pooled in prereduced transport fluid and cultured. Porphyromonas gingivalis was identified primarily by colony morphology under stereoscopic microscope and rapid biochemical tests. Amniotic fluid or plaque samples were homogenized, DNA was extracted, and polymerase chain reaction (PCR) amplification of 16S rRNA with specific and universal primers was carried out. RESULTS: Twenty-six women with threatened premature labor were included: eight with preterm premature rupture of membranes and 18 with preterm labor with intact membranes. Eight women presented with gingivitis, 12 with chronic periodontitis, and six without periodontal disease. Microbial invasion of the amniotic cavity as detected by P. gingivalis PCR was 30.8% (eight of 26 patients). In these eight patients, P. gingivalis was present in both the subgingival samples and the respective amniotic fluid sample. CONCLUSION: The presence of microbial invasion of the amniotic cavity by P. gingivalis could indicate a role for periodontal pathogenic bacteria in pregnant women with a diagnosis of threatened premature labor.     

IgG antibody levels to Porphyromonas gingivalis and clinical measures in children

BACKGROUND: Periodontopathic clinical markers are poorly understood in the pediatric population. Several studies have proposed Porphyromonas gingivalis (P. gingivalis) and an antibody response to the microorganism as factors in periodontal tissue destruction in children. The objective of this study was to examine the prevalence of P. gingivalis in dental plaque and of serum immunoglobulin G (IgG) antibody levels to P. gingivalis, and their relationship to periodontal clinical measures in children. METHODS: Thirty-one subjects, aged 20 to 163 months, participated in this study. Clinical measures examined included gingivitis, plaque, alveolar bone height, age, gender, ethnicity, medical status, caries, and IgG antibody levels to P. gingivalis. Five ml of blood was collected for serum analysis, and IgG antibody levels to P. gingivalis were determined by using enzyme-linked immunosorbent assay. Plaque samples were examined for the presence of P. gingivalis by DNA-DNA checkerboard. Data were analyzed on a person-level basis for relationships to serum IgG antibody levels to P. gingivalis and on a site-specific level for relationships to the presence of P. gingivalis in plaque. RESULTS: A majority (77%) of the subjects were systemically healthy, non-white (74%), and did not have detectable P. gingivalis in their plaque. Fifty-two percent of the subjects had positive serum IgG antibody levels to P. gingivalis. Based on univariate linear regression, factors related to IgG antibody levels to P. gingivalis (P<0.05) included age, average gingival index (GI), average probing depth, and number of teeth with alveolar bone crest to cemento-enamel junction (ABC-CEJ) distances >2 mm. When all clinical measures were considered together, only age remained statistically significantly related to serum IgG antibody levels to P. gingivalis. CONCLUSIONS: Age is one of the most important factors in the development of the immune response to putative microorganisms such as P. gingivalis in children. The role of IgG as a time-sensitive measure of periodontal health in children needs to be investigated further.