By Richard H. Nagelberg, DDS
It is readily apparent from a review of available research that the jury is still out about the relationship between periodontal disease and adverse pregnancy events, specifically preterm low-birth-weight (PTLBW) babies. Epidemiological and interventional studies have shown inconsistent results. Many of these studies were well designed by credible, reputable authors and published in highly respected peer-reviewed journals.
As clinicians, we always turn to research for guidance regarding our approach to disease and treatment planning. When inconsistent results are reported, we need to wait until a consensus is achieved before changing our dialogue and the manner in which we care for our patients. There are, however, some new research results that may indicate the endpoints that further research might start targeting.
Many interventional studies examined the effect of periodontal treatment on the rate of PTLBW births. Some studies showed a positive correlation in which the rate of PTLBW births decreased after periodontal treatment was provided. Others demonstrated no effect, meaning the rate of adverse pregnancy events was the same for both the treatment and control groups. These studies did not break down the data to examine the effect of successful periodontal therapy vs. refractory cases. They merely looked at the effect of periodontal therapy. This is perhaps a key difference and may point the way forward to other research initiatives.
A 2011 study by Jeffcoat et al. (BJOG Jan. 2011; 118(2):250-6.) looked at the effect of successful periodontal therapy on the rate of spontaneous preterm birth. The researchers enrolled 322 pregnant women in the study. Half received SRP and oral hygiene instructions; the other half received only oral hygiene instructions. Spontaneous preterm birth was defined as delivery before 35 weeks of gestation. The results were very revealing. The authors found no difference between the incidence of PTLBW babies in the control group and the periodontal treatment group. These results are consistent with some other studies that just looked at the effect of periodontal treatment. There was, however, a significant relationship between successful periodontal therapy and full-term births in the Jeffcoat study. Furthermore, subjects refractory to periodontal therapy were significantly more likely to have a PTLBW delivery.
Three biological mechanisms for a perio/pregnancy link have been proposed. The first is bacterial spreading, in which oral bacteria are disseminated through the circulation to the amniotic fluid. The second is the systemic effect of inflammatory mediators produced in response to periodontal disease. The third is the fetomaternal immune response, in which the immune system response by both the fetus and the mother produces antibodies to periodontal pathogens.
Although we obviously cannot draw conclusions based on one study, examining the effect of successful periodontal therapy makes a great deal of sense. Successful periodontal treatment is accompanied by a reduction in the inflammatory response and the oral bacterial load. Patients who are refractory to periodontal treatment are essentially in the non-treatment control group. Further studies will need to be undertaken to demonstrate whether or not these results are reproducible.
This type of research is promising since it provides another way to examine the effect of treatment. Up until now, many studies focused on periodontal treatment alone, without differentiating between success and failure, without showing consistent results one way or the other. How realistic is it that more of the same would produce different results? As clinicians, we are in a holding pattern right now, awaiting the results of more studies. Hopefully a different way of examining the effect of treatment will move our knowledge forward, breaking the inconsistent outcomes we currently have.
At this point, it would be appropriate and ethical to indicate to our patients that periodontal disease appears to be a potential risk factor for adverse pregnancy events. There is no reason to avoid a comprehensive, proactive approach to preventing periodontal disease and addressing existing disease for all patients, including those who are, or will likely become, pregnant while we wait for further research. Being accurate in what we say to our patients is important, as is being thorough in the care we provide for them.
DR. RICHARD NAGELBERG has practiced general dentistry in suburban Philadelphia for more than 29 years. He is a speaker, advisory board member, consultant, key opinion leader for several dental companies and organizations, and lecturer on a variety of topics centered on understanding the impact dental professionals have beyond the oral cavity. Contact him at [email protected].
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