By Richard H. Nagelberg, DDS
The oral-systemic interrelationships between periodontal disease/perio bugs and atherosclerosis/cardiovascular disease/diabetes are accepted as risk elements in health care to the same degree as smoking. Not so for periodontal disease, perio bugs, and adverse pregnancy outcomes.
There is a large body of research that supports this link and lots of research that does not; however, at this time some of the reasons for the inconsistent conclusions are being teased out. One of the significant issues involves inconsistent definitions of periodontal disease. This makes systematic reviews and meta-analyses difficult. This should not be a surprise to anyone in the dental profession in view of the inconsistent manner in which periodontal treatment is provided in the United States. A recent examination of insurance submissions for perio-related services by Dr. Charles Cobb revealed that only 5% to 6% of all insurance submissions were for periodontal services, despite approximately 50% of the U.S. population having some form of the disease. Clearly, there is a difference between patient care in offices/clinics and research, but the inconsistency of care and definitions of perio disease cannot be completely unrelated. Similarly, periodontal probing has a significant subjective component and a lack of standardization of probes, probing methods, angulation, pressure, etc. Technology will certainly advance and provide the profession with a way to consistently record accurate clinical data, status of the inflammatory mediators, additional bacterial DNA testing, and genetic risk elements - hopefully in the not-too-distant future.
Another factor affecting inconsistent outcomes involves interventional studies examining the effect of periodontal treatment on pregnancy outcomes. Many of these studies do not demonstrate a reduction in adverse pregnancy outcomes following periodontal therapy. However, few studies drill into the data to see the impact of successful periodontal therapy vs. just the provision of perio therapy. As all clinicians know, perio treatment is not always successful, especially following one round of therapy. Some researchers have begun to look at the results of successful periodontal treatment on pregnancy outcomes.
A 2014 study by Jeffcoat et al. (J Periodontol. Mar. 2014;85(3):446-454.) examined whether specific genetic polymorphisms are associated with successful periodontal therapy in pregnant women with gum disease and whether these genetic polymorphisms are associated with spontaneous preterm birth. The authors of the study concluded that the "[risk of unsuccessful perio treatment was associated with genetic polymorphisms in specific genes that regulate the inflammatory response, one of which is associated with spontaneous preterm birth]". The results revealed "[a significant relationship between a variation in the gene associated with the inflammatory response (specifically prostaglandin E receptor 3) and both periodontal treatment failure and spontaneous preterm birth]." Unsuccessful periodontal therapy is akin to no treatment being provided, as opposed to the bacterial, genetic, and inflammatory impact of successful periodontal intervention.
In 2013, the American College of Obstetricians and Gynecologists' Women's Health Care Physicians' Committee on Health Care for Underserved Women released an opinion (Obstet Gynecol. Aug. 2013;122(2 Pt 1):417-422) which stated, "Although some studies have shown a possible association between periodontal infection and preterm birth, evidence has failed to show any improvement in outcomes after dental treatment during pregnancy."
A 2014 study by Han et al. (Adv Den Res. May 2014;26(1):47-55) looked at the periodontal pathogen Fusobacterium nucleatum. "Fn infection of the fetal-placental unit has been linked to pregnancy complications, including preterm birth, stillbirth, and early-onset neonatal sepsis."
This is quite similar to the two mechanisms by which periodontal disease and perio pathogens are linked to cardiovascular diseases, specifically the contribution to the total inflammatory burden from periodontal disease and the direct effects of perio pathogens on vascular diseases, including Fn, which is considered a facilitator of atherosclerosis.
Obviously, further research needs to be completed to establish the link between oral disease, oral bacteria, and pregnancy outcomes. However, perhaps the emphasis of research will shift as different metrics are evaluated to determine what is going on. Even if a weak relationship is the ultimate conclusion, there is no wiggle room during pregnancy. There is no downside to addressing any level of periodontal disease proactively or providing education and biofilm control devices for whole-mouth disinfection for every patient, especially those who are pregnant while we wait for research to sort it out.
Richard Nagelberg, DDS, has practiced general dentistry in suburban Philadelphia for more than 30 years. He is a speaker, advisory board member, consultant, and key opinion leader for several dental companies and organizations. He lectures on a variety of topics centered on understanding the impact dental professionals have beyond the oral cavity. Contact him at email@example.com.