Oral health during pregnancy

American Family Physician,  April 15, 2008  by Hugh Silk,  Alan B. Douglass,  Joanna M. Douglass,  Laura Silk

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LOOSE (MOBILE) TEETH

Teeth can loosen during pregnancy, even in the absence of gum disease, because of increased levels of progesterone and estrogen affecting the periodontium (i.e., the ligaments and bone that support the teeth). (12)

For uncomplicated loose teeth not associated with periodontal disease (see below), physicians should reassure patients that the condition is temporary, and alone it will not cause tooth loss.

GINGIVITIS

Gingivitis (Figure 3) is the most common oral disease in pregnancy, with a prevalence of 60 to 75 percent. (6) Approximately one half of women with preexisting gingivitis have significant exacerbation during pregnancy. (9) Gingivitis is inflammation of the superficial gum tissue. During pregnancy, gingivitis is aggravated by fluctuations in estrogen and progesterone levels in combination with changes in oral flora and a decreased immune response. Thorough oral hygiene measures, including tooth brushing and flossing, are recommended. Patients with severe gingivitis may require professional cleaning and need to use mouth rinses such as chlorhexidine (Peridex).

PERIODONTITIS

Periodontitis is a destructive inflammation of the periodontium (Figure 4) affecting approximately 30 percent of women of childbearing age. (3) The process involves bacterial infiltration of the periodontium. Toxins produced by the bacteria stimulate a chronic inflammatory response, and the periodontium is broken down and destroyed, creating pockets that become infected. Eventually, the teeth loosen. (13) This process can induce recurrent bacteremia, which indirectly triggers the hepatic acute phase response, resulting in production of cytokines, prostaglandins (i.e., [PGE.sub.2]), and interleukins (i.e., IL-6, IL-8), all of which can affect pregnancy. (14) Elevated levels of these inflammatory markers have been found in the amniotic fluid of women with periodontitis and preterm birth compared with healthy control patients. (15) In one study, researchers found minimal oral bacteria in the amniotic fluid and placenta of women with preterm labor and periodontitis. 16 It seems probable that this inflammatory cascade alone prematurely initiates labor. The mechanism is thought to be similar for low birth weight; the release of [PGE.sub.2] restricts placental blood flow and causes placental necrosis and resultant intrauterine growth restriction. (17)

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Periodontitis and Poor Pregnancy Outcomes

Periodontitis has been associated with several poor pregnancy outcomes, although the mechanism by which this occurs remains unclear and controversy exists. Preterm birth is the leading cause of neonatal morbidity in the United States, costing approximately $26.2 billion per year. (18) Studying the direct effect of any risk factor on the outcomes of preterm birth and low birth weight is extremely difficult because of the many confounding variables that may affect the same outcome.

In a recent systematic review of mainly cross-sectional, case-control, and cohort studies conducted between 1996 and 2006 in 12 countries and three states, investigators identified 24 studies demonstrating a positive relationship between periodontitis and preterm birth, low birth weight, or both. (19) These studies involved approximately 15,000 mothers. Three of the studies were randomized controlled trials (RCTs). Conversely, 14 studies reported no relationship between periodontitis and poor pregnancy outcomes. A recent, large, U.S.-based RCT found no association between periodontitis and preterm birth and low birth weight. (20)