By Richard H. Nagelberg, DDS
The existence of a variety of effects of oral diseases and microbiota beyond the oral cavity is certain. That much we know. The strength of the specific relationships is variable. Some are bulletproof at this time, and others are yet to be determined.
For example, a growing body of research indicates that periodontal disease (PD) elevates the risk for Alzheimer's disease (AD) by more than one mechanism. A recent postmortem study demonstrated that endotoxins from periodontal bacteria can access the brains of patients with AD during life (J Alzheimers Dis. Jan. 1, 2013;36(4):665-677). A 2014 study examined amyloid protein upregulation in periodontitis-affected gingival tissue, suggesting a relationship between periodontal disease and AD pathogenesis (Arch Oral Biol. Mar. 19, 2014;59(6):586-594. [Epub ahead of print]). Is this proof that periodontal disease and periodontal pathogens cause or contribute to Alzheimer's disease? No, but the body of evidence is growing, and it is most likely that the strength of the relationship between PD, periodontal pathogens, and AD will be demonstrated, rather than not. Is it too early to act on the existing information? No, given that acting entails treating periodontal disease to complete resolution in every site.
The evidence has been inconsistent regarding PD and pregnancy. A recent study stated that Fusobacterium nucleatum infection of the fetal-placental unit has been linked to pregnancy complications, including preterm birth, stillbirth, and early-onset neonatal sepsis (Adv Dent Res. May 2014;26(1):47-55). Another 2014 study had the following conclusions: "Periodontitis significantly influenced low birth weight. The increase in the severity of periodontal disease was associated with an increased rate of preterm infants" (Oral Health Prev Dent. 2014;12(1):83-90). Other studies examined the association between PD and preeclampsia (PE). A 2013 meta-analysis stated that PD appears to be a possible risk factor for preeclampsia but that differences in definitions and diagnoses of PD and PE underscore the need for future trials to confirm these results. (PLoS One. 2013 Aug 19;8(8):e71387). Is it too early to act on the current level of information? Given that acting primarily involves maintaining or returning a patient to excellent gingival health and providing the tools for patients to knock down the bacterial load in their mouths on a daily basis, it is certainly not too soon to act. It is equally important not to overstate the evidence and to accurately represent the state of research at this time.
The body of evidence linking periodontal disease and periodontal pathogens with vascular diseases and events, including atherosclerosis and cardiovascular diseases, is so voluminous that the relationships are bulletproof. A 2013 study of the relationship between periodontal disease and recurrent stroke concluded: "[There is an independent association between PD and recurrent vascular events in stroke/TIA patients]" (J Stroke Cerebrovasc Dis. Nov. 2013;22(8):1420-1427). There are innumerable studies demonstrating these associations, and it is past time to act on this information.
The same strength of association exists between periodontal disease and diabetes. Periodontal disease negatively influences glycemic control by increasing insulin resistance. The mechanism appears to be related to the inflammatory cytokines released in response to periodontal disease.
The European Federation of Periodontology (EFP) developed a manifesto in 2014, Periodontal Health for a Better Life, after the first joint EFP/AAP workshop on periodontitis and systemic health. The EFP manifesto calls upon the dental profession to engage in screening and providing preventive advice to patients who are at risk for common chronic diseases and conditions such as cardiovascular disease, diabetes, and cancer. Highlights include the dental team's role in promoting behavior change in their patients aimed at reducing smoking and obesity levels, by promoting healthy nutrition and exercise. The chairman of the National Association of Primary Care Medicine, Dr. Charles Alessi, has strongly endorsed this model and highlighted opportunities for the dental team to engage fully in preventive medicine in support of medical colleagues and in the best interests of public health and patients across England (Br Dent J. Feb. 2014;216(4):159-162).
Our colleagues in England have decided it is time to act on a national scale based on the available research. More research is needed, but only to further elucidate the details and strengths of the mouth/body connections, not demonstrate its existence. It is time to bring the benefit of the research to our patients.
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