||There are two main issues that pose a problem with inferring health from the skeletons of past populations. Selective mortality refers to the fact that we can only research individuals who died and that they might not be representative of all individuals that existed at that age. Heterogeneity in frailty refers to the possibility that not all individuals are equal in terms of their risk of getting sick or dying and the factors that contribute to this difference might be hidden. This study addresses these two problems by looking at tooth crown sizes between individuals who died in childhood versus adulthood, as well as looking at the tooth crown sizes between teeth that show signs of physiological stress (enamel hypoplasia) and teeth that do not. Teeth might turn out smaller than their maximum genetic potential under developmental stress. It is researched if this same developmental stress caused individuals to be frailer than their peers, which might be reflected in reduced longevity and vulnerability to physiological stress episodes.
The mesiodistal and buccolingual tooth crown sizes are measured for the entire dentition of 115 individuals between seven and 50+ years of age from the predominately 19th century Middenbeemster cemetery (the Netherlands). The results show that four buccolingual tooth crown dimensions (maxillary first molar, mandibular canine, first premolar and second molar) were significantly smaller for subadults than for adults, with all buccolingual dimensions having a tendency to be at least a bit smaller. For three of these dimensions, the significantly reduced tooth crown size is wholly attributed to the juveniles having smaller tooth crowns. Six dimensions of four teeth (maxillary second premolar and first molar, mandibular second premolar and first molar) were significantly smaller for teeth with and without enamel hypoplasia. These results indicate that increased frailty, which is reflected in a reduced tooth crown size, does affect mortality, more so for the juveniles than for adolescents. Besides a higher mortality risk, a higher risk of undergoing physiological stressors during early childhood, reflected in enamel hypoplasia presence, is also shown for individuals with reduced tooth crown sizes. Enamel hypoplasia lesions, thus, more likely reflect a weaker individual rather than a stronger individual. This study shows that selective mortality and hidden heterogeneity in frailty are issues that need to be considered in reconstructions of the health of past populations, however teeth are an excellent means to compare circumstances during the period of growth between survivors and non-survivors and to identify if these might account for the differences in longevity.