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Despite advances in the delivery of medical care in Canada, the preterm birth rate and prevalence of low-birth-weight infants have remained relatively unchanged in this country for decades.1 Damaged babies, such as those affected by birth asphyxia and cerebral palsy, and neonatal deaths are almost exclusively the result of preterm birth.1,2 Significant health care dollars are required to care for these individuals, spanning from neonatal life to end-of-life care.
Current strategies used to delay delivery in women who present with threatened preterm labour are limited in number—we often rely on the use of anti-inflammatory medication and antibiotics, with little effect. An inflammatory process has long been considered the common thread of preterm births and low-birth-weight infants, and attention has largely turned to identifying and treating this underlying cause. The dental literature has established a link between systemic illness and periodontal health,3 and the hope was that this would give obstetricians new tools to prevent the devastating outcomes from preterm births. Why then, when there are studies4-9 demonstrating positive relationships between periodontal health and preterm and low-birth-weight infants in terms of both disease and treatment outcomes, does it seem like we've hit a roadblock?
Our clinic at the Women's Hospital Outpatient Department at the Health Sciences Centre in Winnipeg, Manitoba, recently sought to determine if a link between low-birth-weight delivery, preterm birth and periodontal health existed among our patient population. During the planning phases of our study, we wanted to find an objective clinical marker that would identify patients with periodontal disease. Because a full periodontal assessment generally takes over one hour to complete, this method would not be practical at the average obstetrician's office. Therefore, Periodontal Screening and Recording (PSR) represented the best clinical assessment of periodontal disease that was relatively rapid, reproducible and reliable in predicting disease, using periodontal pocket depth, ease of bleeding and presence of calculus to screen patients.10-12
To our surprise, good oral health of women recruited for our study (n = 231) did not confer good obstetrical outcomes. The preterm birth rate was higher in patients without periodontitits (11%) than those with periodontitis (8.9%). The low birth weight rate was small in both patients without periodontitis (5.6%) and with periodontitis (5.9%). Even more surprising, the prevalence of periodontitis in our population was 53%, a rate similar to other obstetrical populations.13 With such a high prevalence of periodontitis, how did we fail to show a relationship between peridontitis and preterm birth or low-birth-weight delivery?
Upon further reflection, it became apparent that the PSR may not accurately reflect periodontal disease, as it omits potentially vital components of disease activity (quiescent, transition or active) and fails to account for normal gingival hypertrophy seen in pregnancy. In our opinion, the PSR does not meet the mark for clinical assessment of this complex physiology.13-15 Despite these shortcomings, guidelines have been issued that include oral hygiene and oral assessment in pregnancy. These guidelines have the potential to redefine the standard of obstetrical care for health care providers, without showing a clear benefit in obstetrical outcomes.16
Physicians need more reliable and reproducible clinical tools that they can use to screen patients for periodontal disease and refer those at high risk for further assessment. In the absence of a truly reliable and accurate clinical marker, we call on periodontists to better define and standardize a screening examination that considers the different stages of disease activity for the diagnosis of periodontitis in pregnancy. Health care providers, patients and our health care system are in need of such guidance.
- Health Canada. Canadian Perinatal Surveillance System. Canadian Perinatal Health Report 2003. Available: www.phac-aspc.gc.ca/rhs-ssg/phic-ispc/index.html (accessed 2012 Mar 7).
- Joseph KS, Kramer MS, Marcoux S, Ohlsson A, Wen SW, Allen A, et al. Determinants of preterm birth rates in Canada from 1981 through 1983 and from 1992 through 1994. N Engl J Med. 1998;339(20):1434-9.
- Kim J, Amar S. Periodontal disease and systemic conditions: a bidirectional relationship. Odontology. 2006;94(1):10-21.
- Dortbudak O, Eberhardt R, Ulm M, Persson GR. Periodontitis, a marker of risk in pregnancy for preterm birth. J Clin Periodontol. 2005;32(1):45-52.
- Khader Y, Ta'ani Q. Periodontal diseases and the risk of preterm birth and low birth weight: a meta-analysis. J Periodontol. 2005;76(2):161-5.
- Vergnes JN, Sixou M. Preterm low birth weight and maternal periodontal status: a meta-analysis. Am J Obstet Gynecol. 2007;196(2):135.e1-7.
- Polyzos NP, Polyzos IP, Mauri D, Tzioras S, Tsappi M, Cortinovis I, et al. Effect of periodontal disease treatment during pregnancy on preterm birth incidence: a meta-analysis of randomized trials. Am J Obstet Gynecol. 2009;200(3):225-32.
- Xiong X, Buekens P, Vastardis S, Yu S. Periodontal disease and pregnancy outcomes: state-of-the-science. Obstet Gynecol Surv. 2007;62(9):605-15.
- Wimmer G, Pihlstrom BL. A critical assessment of adverse pregnancy outcome and periodontal disease. J Clin Periodontol. 2008;35(8 Suppl):380-97.
- Landry RG, Jean M. Periodontal Screening and Recording (PSR) Index: precursors, utility and limitations in a clinical setting. Int Dent J. 2002;52(1):35-40.
- Khocht A, Zohn H, Deasy M, Chang KM. Assessment of periodontal status with PSR and traditional clinical periodontal examination. J Am Dent Assoc. 1995;126(12):1658-65.
- Periodontal screening and recording training program kit. Chicago: American Dental Association and American Academy of Periodontics; 1992.
- Boggess KA. Maternal oral health in pregnancy. Obstet Gynecol. 2008;111(4):976-86.
- Dellinger TM and Livingston HM. Pregnancy: physiologic changes and considerations for dental patients. Dent Clin North Am. 2006;50(4):677-97, ix.
- Silk H, Douglass AB, Douglass JM, Silk L. Oral health during pregnancy. Am Fam Physician. 2008;77(8):1139-44.
- Oral health care during pregnancy and early childhood: practice guidelines. New York State Department of Heath, 2006. Available: http://www.health.ny.gov/publications/0824.pdf (accessed 2012 Mar 7).