Nutrition and Oral Medicine (Nutrition and Health)

72 Part II / Oral and General Healthvitis or periodontitis result in local tissue destruction and also enter the bloodstream,where they may reach significant levels and affect placental tissues. Numerous studieshave demonstrated that genitourinary tract infection increases the risk for prematurerupture of membranes and premature labor (93,94). The bacteria found in periodontaldisease include Gram-negative rods and anaerobes similar to those found in vaginalinfection (95,96). Even at a distant site such as the mouth, these bacteria can lead to therelease of cell-wall components that trigger the maternal release of factors that caninitiate labor or, by spreading to the upper genital tract, could lead to membrane ruptureand premature labor similar to that seen vaginal infection. Several published reportshave demonstrated vaginal infection with organisms that originate from oral (periodontal)sites (97–99). Thus, periodontal disease may influence pregnancy and gestationaldevelopment by direct infection of the genital tract as well as the release of inflammatorymediators that trigger from a distance hormonal events leading to premature laborand premature birth (100).One recent controlled clinical trial demonstrated a significant reduction of prematurebirth associated with prenatal periodontal therapy (101), and several case-control studieshave demonstrated increased risk for premature birth in women with periodontaldisease compared to those without disease (90,92,102), and risk varied with degree ofperiodontal disease. Although there remains considerable work ahead to understand themechanisms and causal relationship, even at this stage public health recommendationsare changing to emphasize dental and periodontal health as an important component ofprenatal care.3. CARIESDental caries is an infectious microbial disease that results in dissolution and destructionof calcified tooth structure. Caries and periodontal disease are probably the mostcommon chronic infectious diseases in the world (103). In industrialized nations, outstandingprogress has been made over the past 50 yr in reducing the incidence andconsequences of dental caries: by 1991, 50% of children aged 5–17 yr had no caries intheir permanent dentition (104), with 80% of the caries observed among only 25% of thechildren. This high-risk group represents children with primarily socioeconomic riskfactors for disease. Over the past 25 yr, the percentage of adults with no caries increasedfrom 15.7% to 19.6% in those aged 18–34 yr and from 12 to 13.5% in those aged 35–54yr (105,106). The trend in older adults has been worsening, with the percentage of teethfree of caries and restorations declining from 10.6 to 7.9% in those aged 55–64 yr andfrom 9.6 to 6.5% in those aged 65–74 yr (105). In particular, there is increased risk forroot caries in these older individuals who have experienced varying degrees of gingivalrecession because of periodontal disease (107,108). Although fluoridation has had thesingle largest impact on the incidence of caries, improved oral hygiene, diet, education,and overall health have also played major roles (109).Although the most common risk factors for caries are lack of daily tooth brushing,frequency of carbohydrate intake, low income, low education, and lack of communityfluoridation, any systemic or local disease that results in salivary hypofunction may dramaticallyincrease the risk for and incidence of dental caries (110,111). Impaired salivarygland neurosecretory action caused by pharmacologic blockade is a common side effectof many medication classes (particularly antihypertensive and antidepressant medica-