A critical assessment of adverse pregnancy outcome and periodontal disease

Roles of oral bacteria in cardiovascular diseases--from molecular mechanisms to clinical cases: Implication of periodontal diseases in development of systemic diseases

Periodontal diseases, some of the most common infectious diseases seen in humans, are characterized by gingival inflammation, as well as loss of connective tissue and bone from around the roots of the teeth, which leads to eventual tooth exfoliation. In the past decade, the association of periodontal diseases with the development of systemic diseases has received increasing attention. Although a number of studies have presented evidence of close relationships between periodontal and systemic diseases, the majority of findings are limited to epidemiological studies, while the etiological details remain unclear. Nevertheless, a variety of recent hypothesis driven investigations have compiled various results showing that periodontal infection and subsequent direct oral-hematogenous spread of bacteria are implicated in the development of various systemic diseases. Herein, we present current understanding in regard to the relationship between periodontal and systemic diseases, including cardiovascular diseases, preterm delivery of low birth weight, diabetes mellitus, respiratory diseases, and osteoporosis.

Periodontal disease and systemic health: current status

The relationship between poor oral health and systemic diseases has been increasingly recognized over the past two decades. Indeed, the clichés "You cannot have good general health without good oral health", "The mouth is part of the body" and "Floss or die", are gaining an increasing momentum. A large number of epidemiological studies have now linked poor oral health with cardiovascular diseases, poor glycaemic control in diabetics, low birthweight preterm babies and a variety of other conditions. The majority have shown an association, although not always strong. As a result, a number of meta-analyses have been conducted and have confirmed the associations and at the same time cautioned that further studies are required, particularly with regard to the effect of periodontal treatment in reducing risk. A number of biologically plausible mechanisms have been put forward to explain the association and there is accumulating evidence in support of them, although at this stage, insufficient to establish causality. Nevertheless, the relationship between poor oral health and systemic diseases has become a significant issue, such that adult oral health can no longer be ignored in overall health strategies. This review provides an update on current understanding of the contribution of poor oral health to systemic diseases, the possible mechanisms involved and the relevance of this for general dental practitioners.

Serum inflammatory mediators in pregnancy: changes after periodontal treatment and association with pregnancy outcomes

BACKGROUND

The purposes of this study were to determine: 1) if periodontal treatment in pregnant women before 21 weeks of gestation alters levels of inflammatory mediators in serum; and 2) if changes in these mediators are associated with birth outcomes.

METHODS

A total of 823 pregnant women with periodontitis were randomly assigned to receive scaling and root planing before 21 weeks of gestation or after delivery. Serum obtained between 13 and 16 weeks, 6 days (study baseline) and 29 to 32 weeks of gestation was analyzed for C-reactive protein; prostaglandin E(2); matrix metalloproteinase-9; fibrinogen; endotoxin; interleukin (IL)-1 beta, -6, and -8, and tumor necrosis factor-alpha. Cox regression, multiple linear regression, and the t, chi(2), and Fisher exact tests were used to examine associations among the biomarkers, periodontal treatment, and gestational age at delivery and birth weight.

RESULTS

A total of 796 women had baseline serum data, and 620 women had baseline and follow-up serum and birth data. Periodontal treatment did not significantly alter the level of any biomarker (P >0.05). Neither baseline levels nor the change from baseline in any biomarker were significantly associated with preterm birth or infant birth weight (P >0.05). In treatment subjects, the change in endotoxin was negatively associated with the change in probing depth (P <0.05).

CONCLUSIONS

Non-surgical mechanical periodontal treatment in pregnant women, delivered before 21 weeks of gestation, did not reduce systemic (serum) markers of inflammation. In pregnant women with periodontitis, levels of these markers at 13 to 17 weeks and 29 to 32 weeks of gestation were not associated with infant birth weight or a risk for preterm birth.

Relationship between iron-deficiency anemia and periodontal status in female patients

BACKGROUND

The aim of this study was to evaluate the periodontal status of patients with iron-deficiency anemia (IDA) and the correlation of changes in serum and gingival crevicular fluid (GCF) ferritin levels after periodontal therapy.

METHODS

Nineteen female patients with anemic hematologic values were classified as group A, and 20 healthy females with normal hematologic values were classified as group B. After group A was recruited, group B was enrolled with patients who had similar gingival indices as group A. At baseline and the 3-month follow-up visit, clinical periodontal indices and hematologic parameters were recorded, and GCF samples were taken. All patients received an oral hygiene-improvement session followed by scaling, and sites with >4-mm probing depths received root planing. At the 3-month follow-up visit, all measurements and analyses were repeated.

RESULTS

During the follow-up period, all clinical indices decreased in both groups (P <0.05), but the gingival index in group A did not change. The GCF ferritin concentration showed statistically significant decreases (P <0.05), but total amounts of ferritin in GCF did not change. No significant correlation was found between serum and GCF ferritin levels.

CONCLUSION

The findings of this study showed that changes in serum ferritin levels did not correlate with the GCF ferritin levels, and IDA was not a direct risk factor for periodontal diseases.

The biology, prevention, diagnosis and treatment of periodontal diseases: scientific advances in the United States

BACKGROUND

Major scientific advances in periodontology in the past 150 years have fundamentally changed how clinicians detect and treat periodontal diseases. These advances include the demonstration that gingivitis and periodontitis are biofilm-induced infections caused by components of the indigenous oral microbiota, and that host inflammatory-immunologic responses to these microbial challenges are responsible for most of the observed tissue damage.

TYPES OF STUDIES REVIEWED

In this brief overview, the authors focus on the discovery of the relationships between dental plaque and the host periodontal tissues. They highlight some of the pioneers in the United States who shaped new approaches to prevention and treatment of periodontal disease.

RESULTS

Biofilms that cause gingivitis and periodontitis are complex polymicrobial communities that are resistant to antimicrobial agents and host defense mechanisms. An increased understanding of natural inflammation-resolving mechanisms suggests that control of inflammation is at least as important as is antimicrobial therapy in the treatment of periodontal infections. Data from randomized controlled clinical trials have shown that most conventional forms of periodontal therapy are effective as long as patients comply with posttreatment maintenance programs.

CONCLUSIONS

Many mechanisms involved in the repair and regeneration of periodontal tissues have been identified. Results of laboratory studies of factors that enhance prevention and treatment of periodontal disease have made the transition to clinical practice. Advances in the fields of molecular biology, human genetics and stem cell biology have set the stage for significant discoveries that will pave the way for the development of procedures needed for the predictable regeneration of periodontal tissues. As a result, new generations of people in the United States can expect to retain a healthy and functional dentition for a lifetime.

Porphyromonas gingivalis invades human trophoblasts and inhibits proliferation by inducing G1 arrest and apoptosis

Porphyromonas gingivalis is an oral pathogen that is also associated with serious systemic conditions such as preterm delivery. Here we investigated the interaction between P. gingivalis and a cell line of extravillous trophoblasts (HTR-8) derived from the human placenta. P. gingivalis internalized within HTR-8 cells and inhibited proliferation through induction of arrest in the G1 phase of the cell cycle. G1 arrest was associated with decreased expression of cyclin D and of CDKs 2, 4 and 6. In addition, levels of CDK inhibitors p15, p16, p18 and p21 were increased following P. gingivalis infection. The amount of Rb was diminished by P. gingivalis, and transient overexpression of Rb, with concomitant upregulation of phospho-Rb, relieved P. gingivalis-induced G1 arrest. HTR-8 cells halted in the G1 phase became apoptotic, and apoptosis was accompanied by an increase in the ratio of Bax/Bcl-2 and increased activity of caspases 3, 7 and 9. HTR-8 cells infected with P. gingivalis also exhibited a sustained activation of ERK1/2, and knock-down of ERK1/2 activity with siRNA abrogated both G1 arrest and apoptosis. Thus, P. gingivalis can invade placental trophoblasts and induce G1 arrest and apoptosis through pathways involving ERK1/2 and its downstream effectors, properties that provide a mechanistic basis for pathogenicity in complications of pregnancy.

Reducing stillbirths: prevention and management of medical disorders and infections during pregnancy

BACKGROUND

An estimated two-thirds of the world's 3.2 million stillbirths occur antenatally, prior to labour, and are often overlooked in policy and programs. Poorly recognised, untreated or inadequately treated maternal infections such as syphilis and malaria, and maternal conditions including hypertensive disorders, are known risk factors for stillbirth.

METHODS

We undertook a systematic review of the evidence for 16 antenatal interventions with the potential to prevent stillbirths. We searched a range of sources including PubMed and the Cochrane Library. For interventions with prior Cochrane reviews, we conducted additional meta-analyses including eligible newer randomised controlled trials following the Cochrane protocol. We focused on interventions deliverable at the community level in low-/middle-income countries, where the burden of stillbirths is greatest.

RESULTS

Few of the studies we included reported stillbirth as an outcome; most that did were underpowered to assess this outcome. While Cochrane reviews or meta-analyses were available for many interventions, few focused on stillbirth or perinatal mortality as outcomes, and evidence was frequently conflicting. Several interventions showed clear evidence of impact on stillbirths, including heparin therapy for certain maternal indications; syphilis screening and treatment; and insecticide-treated bed nets for prevention of malaria. Other interventions, such as management of obstetric intrahepatic cholestasis, maternal anti-helminthic treatment, and intermittent preventive treatment of malaria, showed promising impact on stillbirth rates but require confirmatory studies. Several interventions reduced known risk factors for stillbirth (e.g., anti-hypertensive drugs for chronic hypertension), yet failed to show statistically significant impact on stillbirth or perinatal mortality rates. Periodontal disease emerged as a clear risk factor for stillbirth but no interventions have reduced stillbirth rates.

CONCLUSION

Evidence for some newly recognised risk factors for stillbirth, including periodontal disease, suggests the need for large, appropriately designed randomised trials to test whether intervention can minimise these risks and prevent stillbirths. Existing evidence strongly supports infection control measures, including syphilis screening and treatment and malaria prophylaxis in endemic areas, for preventing antepartum stillbirths. These interventions should be incorporated into antenatal care programs based on attributable risks and burden of disease.