Antecedents and associations of root surface caries experience among 38-year-olds

To determine whether coronal caries experience through to the 30s predicts root surface caries experience by age 38.

Prospective study of a complete birth cohort (n = 1,037) born in 1972/73 in Dunedin, New Zealand. Dental examinations were conducted at ages 5, 9, 15, 18, 26, 32 and 38. Root surface caries data were first collected at age 38. Data from ages 5 through 32 were used previously to identify low, medium and high life course trajectories of caries experience and plaque accumulation.

Of the 916 dentate individuals examined at age 38, 23.0% had 1+ root DFS, 17.2% had 1+ root DS and 11.4% had 1+ root FS. The mean root DS, FS and DFS were 0.6 (SD 3.5), 0.3 (SD 1.1) and 0.9 (SD 3.8), respectively. The mean Root Caries Index (RCI) score was 7.2% (SD 18.0). Age 38 coronal DMFS and root surface caries DFS were only weakly correlated (r = 0.32), but root surface caries experience was strongly associated with coronal caries trajectory, with the mean RCI in the low, medium and high caries trajectory groups being 4.4, 8.0 and 13.5%, respectively (p < 0.0001); their prevalence of 1+ root DFS was 14.5, 25.9 and 42.2% (p < 0.0001). Those in the high coronal caries trajectory were more likely to have 1+ root surface DFS (odds ratio = 3.83; 95% CI = 2.33-6.30); for the medium trajectory, the odds ratio was 1.86 (95% CI = 1.25-2.75).

Lifelong coronal caries experience (represented by discrete longitudinal trajectories of caries experience) is indeed a risk factor for root surface caries experience by age 38.