John R. Elter

Periodontal Disease and Coronary Heart Disease A Reappraisal of the Exposure

Background—Results from studies relating periodontal disease to cardiovascular disease have been mixed. Residual confounding by smoking and use of clinical measures of periodontal disease rather than measures of infection have been 2 major criticisms. The aims of this study were to investigate relationships between prevalent coronary heart disease (CHD) and 2 exposures, (1) clinical periodontal disease and (2) IgG antibodies to 17 oral organisms, and to evaluate the role of smoking in these relationships. Methods and Results—Our study is based on a subset of participants in the Atherosclerosis Risk in Communities (ARIC) Study, who received a complete periodontal examination during visit 4 (1996–1998). The exposures were periodontal status and serum IgG antibody levels against 17 periodontal organisms, and the outcome was prevalent CHD at visit 4. Multivariable analyses indicate that periodontal status is not significantly associated with CHD in either ever smokers or never smokers. Similar analyses evaluating antibodies indicate that high antibodies (above the median) to Treponema denticola (odds ratio [OR]=1.7; 95% CI, 1.2 to 2.3), Prevotella intermedia (OR=1.5; 95% CI, 1.1 to 2.0), Capnocytophaga ochracea (OR=1.5; 95% CI, 1.1 to 2.1), and Veillonella parvula (OR=1.7; 95% CI, 1.2 to 2.3) are significantly associated with CHD among ever smokers, whereas Prevotella nigrescens (OR=1.7; 95% CI, 1.1 to 2.6), Actinobacillus actinomycetemcomitans (OR=1.7; 95% CI, 1.2 to 2.7), and Capnocytophaga ochracea (OR=2.0; 95% CI, 1.3 to 3.0) were associated with CHD among never smokers. Conclusions—Clinical signs of periodontal disease were not associated with CHD, whereas systemic antibody response was associated with CHD in ever smokers and never smokers. These findings indicate that the quality and quantity of the host response to oral bacteria may be an exposure more relevant to systemic atherothrombotic coronary events than clinical measures.

Porphyromonas gingivalis Infection during Pregnancy Increases Maternal Tumor Necrosis Factor Alpha, Suppresses Maternal Interleukin-10, and Enhances Fetal Growth Restriction and Resorption in Mice

ABSTRACT Epidemiological studies have shown a potential association between maternal periodontitis and pregnancy complications. We used a pregnant murine model to study the effect of infection with the periodontal pathogen Porphyromonas gingivalis on pregnancy outcomes. Female BALB/c mice were inoculated with heat-killed P. gingivalis (109 CFU) in a subcutaneous chamber and mated 2 weeks later. At gestation day (GD) 7.5, mice were challenged with live P. gingivalis (107 CFU) (n = 20) or broth (control; n = 8) and sacrificed at GD 16.5. Fetal growth restriction (FGR, <0.46 g) was defined as fetuses with weights 2 standard deviations (SD) smaller than controls (0.56 ± 0.05 g [mean ± SD]). Among the 20 challenged mice, 8 had both normal-weight (0.51 ± 0.11 g) and FGR (0.34 ± 0.1 g) fetuses within the same litter. All other challenged dams had normal-weight fetuses (0.57 ± 0.04 g). Maternal liver, uterus, and spleen samples were examined for P. gingivalis DNA using a PCR technique. Of the eight challenged mice with FGR fetuses, three had PCR signals for P. gingivalis in liver and uterus, but not in the spleen. Liver, uterus, and spleen were negative for P. gingivalis DNA among all other challenged and control mice. In serum of dams with FGR fetuses, tumor necrosis factor alpha levels were elevated significantly, while interluekin-10 levels were significantly reduced compared to levels in dams with normal fetuses. P. gingivalis-specific serum immunoglobulin G levels were significantly elevated in dams with FGR fetuses compared to dams without any FGR fetuses. These data demonstrate that P. gingivalis-induced murine FGR is associated with systemic dissemination of the organism and activated maternal immune and inflammatory responses.

Relationship of Periodontal Disease and Edentulism to Stroke/TIA

Periodontitis has been shown to increase the systemic inflammatory response, which has been implicated in atherosclerosis and cerebrovascular events. We hypothesized an association between periodontitis or edentulism and Stroke/TIA in the ARIC Study. Data on 9415 dentate and 1491 edentulous adults included demographics, cardiovascular outcomes, lifestyle, laboratory measures, and, for 6436 of the dentate, a dental examination. The dependent variable was Stroke/TIA, and the exposure was extent (%) of attachment level 3+ millimeters (AL). Quartiles of AL and edentulism were compared for Stroke/TIA using odds ratios (OR) and 95% confidence intervals (CI), and confounders were controlled by logistic regression. Stroke/TIA was prevalent in 13.5% of periodontal examinees, 15.6% of dentate non-examinees, and 22.5% of edentulous persons. The highest quartile of AL (OR 1.3, CI 1.02-1.7) and edentulism (OR 1.4, CI 1.5-2.0) were associated with Stroke/TIA.

Porphyromonas gingivalis Infection in Pregnant Mice Is Associated with Placental Dissemination, an Increase in the Placental Th1/Th2 Cytokine Ratio, and Fetal Growth Restriction

ABSTRACT Our previous animal studies showed that maternal Porphyromonas gingivalis infection in a subcutaneous chamber is associated with hepatic and uterine translocation, as well as systemic induction of maternal inflammatory responses, both of which were associated with fetal growth restriction (FGR). However, P. gingivalis-challenged dams had fetuses with either FGR (2 standard deviations below mean weight of nonchallenged dams) or normal weight. Therefore, the objective of this study was to determine whether maternal infection with P. gingivalis compromises normal fetal development via direct placental invasion and induction of fetus-specific placental immune responses characterized by a proinflammatory Th1-type cytokine profile. P. gingivalis-specific DNA was detected in placentas and fetuses of FGR and normal littermates from P. gingivalis-infected dams. Th1- and Th2-type cytokine mRNA as well as tumor necrosis factor alpha and transforming growth factor β2 mRNA were examined in placental tissue by using reverse transcription-PCR to determine Th1/Th2 ratios. For eight litters containing both normal-weight and FGR fetuses, P. gingivalis DNA was detected only in the placentas of FGR fetuses. All fetuses and all amniotic fluid samples from infected and control dams were negative for P. gingivalis DNA. mRNA levels of gamma interferon and interleukin-2 (IL-2) were significantly increased in placentas of FGR fetuses, while expression of IL-10 was significantly decreased in the same group. These data indicate that, in P. gingivalis-challenged dams, within each litter there is placenta-specific translocation of P. gingivalis that results in growth restriction of the targeted fetus, which is associated with a shift in the placental Th1/Th2 cytokine balance.

Movement of Teeth Adjacent to Posterior Bounded Edentulous Spaces

Bounded edentulous spaces (BES)-a missing posterior tooth with intact adjacent teeth-are thought to lead to arch collapse resulting from the movement of adjacent teeth. To determine the rate of change in distance between teeth adjacent to a BES, we examined three successive measurable radiographs of 116 untreated posterior BES cases. The distance between the teeth (DBT) adjacent to the space was measured, and change in DBT (A DBT) between pre-extraction and follow-up radiographs was calculated. We used linear spline regression to construct models for tooth movement and to identify factors associated with A DBT. The mean A DBT was < 1 mm during the first year post-extraction, and the DBT continued to decrease at a successively slower rate each following year. Overall and for each tooth type, the greatest rates of decrease in DBT were seen in the zero to two-year period. In a multivariable model, time since extraction and tooth type were significantly associated with A DBT. These findings suggest that movement of teeth adjacent to a posterior BES after the first two years is usually gradual and minor within the time frame of this study.