Exploring directional and fluctuating asymmetry in the human palate during growth

Abstract

Objectives: Palate morphology is constantly changing throughout an individual's lifespan, yet its asymmetry during growth is still little understood. In this research, we focus on the study of palate morphology by using 3D geometric morphometric approaches to observe changes at different stages of life, and to quantify the impact of directional and fluctuating asymmetry on different areas at different growth stages. Materials and Methods:The sample consists of 183 individuals (1-72 years) from two identified human skeletal collections of 19th and early 20th Century Italian contexts. A 3D-template of 41 (semi)landmarks was applied on digital palate models to observe morphological variation during growth.Results: Asymmetrical components of the morphological structure appears multidirectional on the entire palate surface in individuals <2 years old and become oriented (opposite bilateral direction) between 2 and 6 years of age. Specifically, directional asymmetry differentially impacts palate morphology at different stages of growth. Both the anterior and posterior palate are affected by mild alterations in the first year of life, while between 2 and 6 years asymmetry is segregated in the anterior area, and moderate asymmetry affects the entire palatal surface up to 12 years of age. Our results show that stability of the masticatory system seems to be reached around 13-35 years first by females and then males. From 36 years on both sexes show similar asymmetry on the anterior area. Regarding fluctuating asymmetry, interindividual variability is mostly visible up to 12 years of age, after which only directional trends can be clearly observed at a group level.

Fluctuating Asymmetry and Stress in Macaca fuscata: Does Captivity Affect Morphology?

“…The degree and modes of anatomical asymmetry have been extensively studied for decades both in vertebrates and invertebrates [1][2][3][4][5][6][7][8][9][10][11]. In nature, we can observe principally three different types of asymmetry:…”

Correlations of palatal surface area with anthropometric dimensions of the head and face

“…These participants were considerably younger than the volunteers in the current study with a mean age of 42.6 ± 14.8 years. In this light, is has to be noted that maturation of female facial structures starts at an earlier age compared to males [ 24 ]. For this reason, in younger aged groups, there is a significant difference in palatal surface area between the two sexes, which explains why the study by Kerr et al .…”

Scientific and Ethical Aspects of Identified Skeletal Series: The Case of the Documented Human Osteological Collections of the University of Bologna (Northern Italy)

“…The latter include methodological studies focused on estimation of age-at-death and attribution of sex [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61], the study of entheseal changes in modern humans [62][63][64][65][66][67], and the discussion of their variability among extinct taxa [1][2][3][4]. Additional topics of investigation have been the various expression and demographic distribution of skeletal morphological variants and pathological changes [68][69][70][71], as well as dental and palate traits [72][73][74][75][76]. These collections have also offered excellent biological, demographic, and biocultural background in the analysis and discussion of case studies [77][78][79].…”