Dimensional and discrete dental trait asymmetry relationships

Abstract

Inuit (Eskimos) from the Foxe Basin region of the Northwest Territories, Canada, were studied to ascertain the amount of dimensional and morphological asymmetry in their dentitions. The results indicate that dimensional asymmetry does not appear to be greater on either the maxillary or mandibular teeth. Both types of asymmetry show partial conformity to the model of tooth fields with an increasing amount of asymmetry as one goes distally in each tooth group. The morphological asymmetry exception, the mandibular incisors, follows Dahlberg's "Field Concept." Rank-order correlations between the amount of dimensional asymmetry and morphological asymmetry reveal no detectable patterns. There appear to be no associations between the presence or absence of morphological asymmetry and the size of the tooth. This lack of association might be explained by differences in developmental timing of tooth dimensions and morphological traits; however, such a hypothesis requires experimental testing. In this population and those for which published results are available, it is practically impossible to overcome the "noise" level and test recent hypotheses regarding random dental asymmetry.

Prenatal Psychological Stress, Dermatoglyphic Asymmetry and Pregnancy Outcome in the Pigtailed Macaque (<i>Macaca nemestrina</i>)

“…In 1962, Van Valen [24] applied the concept to the denti tion, and since then more than 25 publica tions have appeared dealing specifically with fluctuating dental asymmetry alone [25], while others have focussed on skeletal di mensions [26][27][28], bone and dental density [29,30], and dermatoglyphic features in cluding ridge counts [31][32][33][34] and the atd angle [35,36], The majority of studies have treated the presence of fluctuating asymme try as evidence for the presence of a stressor during development, in particular prenatal development [28-30, 37, 38], Consistent with this view is the finding that the degree of asymmetry is positively correlated with the magnitude of the environmental stressor [29,39], Some workers, however, have ques tioned the interpretation of fluctuating asymmetry as a general and biologically valid indicator of developmental decanaliza tion on an individual basis [25,40] or as a simple monitor of environmental stress alone [41][42][43]; while others have emphasized the confounding effects introduced into the results by sample size and measurement er ror [25,41,44], It is clear that more experi mental studies are needed to identify the nature of environmental stressors, including those of a psychosocial origin, and the extent of their association, if any, with the presence of increased fluctuating asymmetry.…”

A new perspective on fluctuating odontometric asymmetry in South African Negroes

“…The first study (Baume and Crawford, 1980) pointed to a negative correlation between these two variables, while the most recent study suggested that there is no association between metrical and morphological dental asymmetry (Mayhall and Saunders, 1986).…”

“…Numerous investigations have underlined the usefulness of fluctuating asymmetry as an indirect measure of environmental stress in human populations (Bailit et al, 1970;Perzigian, 1977;Harris and Nweeia, 1980;Kieser andGroeneveld, 1986a, 1988;Kieser et al, 1986a,b;Mayhall and Saunders, 1986;Mizoguchi, 1986;Livshitz et al, 1988). The magnitude of fluctuating odontometric asymmetry in man has also been related to consanguinity (Niswander and Chung, 1965;Syarez, 1974;DiBennardo and Bailit, 19781, to chromosomal aneuploidy (Barden, 1980;Townsend, 1983;Townsend et al, 1986), and to clefting of the lip and palate (Sofaer, 1979).…”

Fluctuating asymmetry in dental and mandibular nonmetric traits as evidence for childcare sex bias in 19th/20th century Portugal

“…These small samples were defined as those with n<30, or n<20 for age group comparisons. Removal of bilateral absences diminishes the effect of different trait presence in overall asymmetry, making the sexes and age groups more easily comparable (Mayhall and Saunders, 1986). The minimum number of individuals allowing trait inclusion on the "comparable large sample FA" was determined to exclude very small samples in averaged or summed results.…”

“…However, further research is required to clarify the connection (Markow, 1995;Palmer, 1996;Van Dongen et al, 1999). The relationship between FA and developmental instability has rarely been studied in dental morphology studies, with only three published studies in the last 30 years (Bollini et al, 2009;Mayhall and Saunders, 1986;Noss et al, 1983).…”