Reliability of third molar probing measures and the systemic impact of third molar periodontal pathology

This study examined the reliability of assessing clinical periodontal measures on third molars, and the association between oral inflammation with periodontal pathology including third molars, and systemic inflammation including negative obstetric outcomes.

Reliability of third molar probing depth (PD) was assessed for 41 patients by trained examiners. The data for the association between oral inflammation with periodontal pathology and systemic outcomes were derived from an IRB-approved study, "Oral Conditions and Pregnancy." Full mouth periodontal exams including third molars were conducted at less than 24 weeks of pregnancy. Periodontal status, moderate/severe periodontal disease (15 or more sites PD > or =4 mm) was considered as a possible predictor of systemic inflammation and pre-term birth. The upper quartile of the extent of PD for third molars alone (PD > or =4 mm) also was considered as a possible exposure variable for the same outcomes. Chi-square and t tests were used to determine statistical significance (0.05). Significant predictor variables were included in multivariate models. Unconditional logistic multivariate models were used to derive odds ratios (OR) and 95% confidence intervals (CI).

Reliability of PD within 1 mm was excellent, and similar for third molars and non-third molars. Data from 1,020 obstetric patients were available for analysis. Eighteen percent of the patients delivered preterm, at less than 37 weeks. Having moderate/severe periodontal disease excluding third molars, was significantly associated with preterm birth (P = .008). Results were more significant if third molars were included (P = .0005). With multivariate models moderate/severe periodontal disease at enrollment including third molar PD, was associated with preterm birth (OR, 1.7; 95% CI, 1.1, 2.6). If only the extent of third molar PD was considered, odds also were increased for preterm birth (OR, 2.4; 95% CI, 1.1, 5.2). If only the extent of third molar PD was considered at enrollment, odds were increased for serum markers of systemic inflammation, elevated serum CRP, and oxidative stress, 8-isoPGF(2alpha).

Dental examiners could reliably assess clinical periodontal measures on third molars. Third molars should be included in studies of systemic outcomes associated with oral inflammation. Women of child-bearing age should be made aware of the systemic risks of oral inflammation with third molar periodontal pathology.