A four-year longitudinal study of tooth loss in the very old

Objectives: Relatively few studies have addressed the issue of tooth loss among elderly population aged 80+ years. Thus, the purpose of this study was to explore the rate of and intra-oral risk factors for tooth loss in the very old.
Methods: The subjects of this study were drawn as a subsample from our previous cohort study conducted in Niigata, Japan. A total of 85 subjects aged 80 years with 20+ teeth participated in this longitudinal study. The prosthetic status and abutment function of 2,134 teeth were recorded at baseline and the rate of tooth loss over the four-year observation period was compared by intra-oral risk factors.
Results: Tooth loss was found in 44 (51.8%) subjects and eight subjects lost 3+ teeth. Among 2,134 retaining teeth at baseline, 83 were lost during the study period. Tooth loss was found most frequently in molars (6.6%) and least in canines (2.4%). Although sound teeth were most resistant to tooth loss (1.4%), abutment teeth for fixed/removable partial dentures were more likely to be lost (11.1% and 14.3%, respectively). Moreover, a lower rate of tooth loss was found among subjects with more teeth: 10.6% (19/180 teeth), 4.9% (29/558 teeth) and 2.6% (35/1,366 teeth) among those with 20, 21-24 and 25-32 teeth, respectively.
Conclusions: The findings of this study imply that dental prostheses have some adverse effect on tooth loss in the elderly. Moreover, retaining more teeth may be the key to decrease the risk of tooth loss among elderly people with 20+ teeth.