Benefits of Periodontal Therapy When Preterm Birth Threatens

Obstetric outcomes after treatment of periodontal disease during pregnancy: systematic review and meta-analysis

OBJECTIVE

To examine whether treatment of periodontal disease with scaling and root planing during pregnancy is associated with a reduction in the preterm birth rate.

DESIGN

Systematic review and meta-analysis of randomised controlled trials.

DATA SOURCES

Cochrane Central Trials Registry, ISI Web of Science, Medline, and reference lists of relevant studies to July 2010; hand searches in key journals.

STUDY SELECTION

Randomised controlled trials including pregnant women with documented periodontal disease randomised to either treatment with scaling and root planing or no treatment.

DATA EXTRACTION

Data were extracted by two independent investigators, and a consensus was reached with the involvement a third. Methodological quality of the studies was assessed with the Cochrane's risk of bias tool, and trials were considered either high or low quality. The primary outcome was preterm birth (<37 weeks). Secondary outcomes were low birthweight infants (<2500 g), spontaneous abortions/stillbirths, and overall adverse pregnancy outcome (preterm birth <37 weeks and spontaneous abortions/stillbirths).

RESULTS

11 trials (with 6558 women) were included. Five trials were considered to be of high methodological quality (low risk of bias), whereas the rest were low quality (high or unclear risk of bias). Results among low and high quality trials were consistently diverse; low quality trials supported a beneficial effect of treatment, and high quality trials provided clear evidence that no such effect exists. Among high quality studies, treatment had no significant effect on the overall rate of preterm birth (odds ratio 1.15, 95% confidence interval 0.95 to 1.40; P=0.15). Furthermore, treatment did not reduce the rate of low birthweight infants (odds ratio 1.07, 0.85 to 1.36; P=0.55), spontaneous abortions/stillbirths (0.79, 0.51 to 1.22; P=0.28), or overall adverse pregnancy outcome (preterm births <37 weeks and spontaneous abortions/stillbirths) (1.09, 0.91 to 1.30; P=0.34).

CONCLUSION

Treatment of periodontal disease with scaling and root planing cannot be considered to be an efficient way of reducing the incidence of preterm birth. Women may be advised to have periodical dental examinations during pregnancy to test their dental status and may have treatment for periodontal disease. However, they should be told that such treatment during pregnancy is unlikely to reduce the risk of preterm birth or low birthweight infants.

Periodontal infection and preterm birth: successful periodontal therapy reduces the risk of preterm birth

OBJECTIVE

This study tested the hypothesis that successful periodontal treatment was associated with a reduction in the incidence of spontaneous preterm birth (PTB).

DESIGN

This was a randomised, controlled, blinded clinical trial.

SETTING

Hospital outpatient clinic.

POPULATION

Pregnant women of 6-20 weeks of gestation were eligible.

METHODS

Of 322 pregnant women with periodontal disease, 160 were randomly assigned to receive scaling and root planing (SRP, cleaning above and below the gum line), plus oral hygiene instruction, whereas the remaining 162 received only oral hygiene instruction and served as an untreated control group. Subjects received periodontal examinations before and 20 weeks after SRP, and were classified blindly according to the results of treatment into two groups: successful ('non-exposure') and unsuccessful ('exposure') treatment. Groups were compared using standard inferential statistics; dichotomous variables were compared using the chi-square test or logistic regression. Results are presented in terms of odds ratios.

MAIN OUTCOME MEASURE

The main outcome measure was spontaneous preterm birth before 35 weeks of gestation.

RESULTS

No significant difference was found between the incidence of PTB in the control group (52.4%; n = 162) and the periodontal treatment group (45.6%; n = 160) (P < 0.13, Fisher's exact test). The incidence of PTB was compared within the periodontal treatment group, considering the success of therapy. A logistic regression analysis showed a strong and significant relationship between successful periodontal treatment and full-term birth (adjusted odds ratio 6.02; 95% CI 2.57-14.03). Subjects refractory to periodontal treatment were significantly more likely to have PTB.

CONCLUSIONS

A beneficial effect on PTB may be dependent on the success of periodontal treatment.

Design, Operation, and Interpretation of Clinical Trials

Randomized controlled clinical trials offer the best evidence for changing clinical practice and informing public health policy. Using examples from the literature, this paper reviews clinical trials for those who may be unfamiliar with their design, operation, and interpretation. In the design of a clinical trial, the question to be answered and a clinically meaningful outcome must be clearly defined. Ethics must be considered, sample size carefully estimated, and use of biomarkers and surrogate outcomes understood. Prominent issues in trial implementation include developing a manual of operations, trial registration, subject recruitment and retention, use of a data coordinating center, and data and safety monitoring. Interpretation of clinical trials requires understanding differences between efficacy and effectiveness; superiority, equivalence, and non-inferiority; intent-to-treat; primary and secondary analyses; and limitations of unregistered small clinical trials compared with large multi-center Phase III trials that are more likely to be representative of a population and change clinical practice or public health policy.

Doxycycline [corrected] inhibits mononuclear cell-mediated connective tissue breakdown

Chronic periodontitis is the most common chronic inflammatory disease and has been associated with an increased risk for serious medical conditions including cardiovascular disease (CVD). Endotoxin (lipopolysaccharide), derived from periodontopathogens, can induce the local accumulation of mononuclear cells in the inflammatory lesion, increasing proinflammatory cytokines and matrix metalloproteinases (MMPs), resulting in the destruction of periodontal connective tissues including bone. In this study, we show that doxycycline, originally developed as a broad-spectrum tetracycline antibiotic (and, more recently, as a nonantimicrobial therapy for chronic inflammatory periodontal and skin diseases), can inhibit extracellular matrix degradation in cell culture mediated by human peripheral blood-derived monocytes/macrophages. The mechanisms include downregulation of cytokines and MMP-9 protein levels and the inhibition of the activities of both collagenase and MMP-9. These pleiotropic, but nonantibiotic, effects of doxycycline explain, at least in part, its therapeutic potential for various chronic inflammatory diseases including periodontitis, and may reduce the risks of systemic diseases (e.g. CVDs, less manageable diabetes) associated with this and other local diseases.