No significant difference in the levels of dental fluctuating asymmetry between hypoplastic and non-hypoplastic skeletal groups from the Joseon Dynasty (mid 15th-early 20th century), South Korea

Abstract

Objectives: As part of efforts to explore the relationship between linear enamel hypoplasia (LEH) and dental fluctuating asymmetry (DFA), DFA levels were compared between a hypoplastic group and a non-hypoplastic group. Since both LEH and DFA are pathological indicators of environmental stress which are represented by teeth, it was hypothesized that the hypoplastic group would exhibit higher levels of DFA than the non-hypoplastic group.

Design: Total of 136 sets of Korean skeletal remains from the Joseon Dynasty (mid 15th-early 20th century, South Korea) were used. To test the hypothesis, DFA levels of both groups were compared by two-way ANOVA after examining some issues related to FA research such as measurement error, type of asymmetry, and size dependence.

Result: Contrary to the anticipations of many relavant studies, the hypothesis of this study was not supported (F=3.469, p=0.063). That is, the DFA levels of the two groups did not differ significantly, which implies that LEH and DFA do not occur concordantly.

Conclusion: As to the reason for the result of the present study, it was speculated that (1) different kinds and/or degrees of stressors may influence the occurrence of LEH and DFA, or (2) traditional measuring methods used for DFA research may not reflect true DFA levels. Based on this study, it is recommended that both LEH and DFA should be utilized and reported independently in future research on the environmental stress and nutritional status of human populations.