TY - JOUR

T1 - Exploring directional and fluctuating asymmetry in the human palate during growth

AU - Oxilia, Gregorio

AU - Menghi Sartorio, Jessica C.

AU - Bortolini, Eugenio

AU - Zampirolo, Giulia

AU - Papini, Andrea

AU - Boggioni, Marco

AU - Martini, Sergio

AU - Marciani, Filippo

AU - Arrighi, Simona

AU - Figus, Carla

AU - Marciani, Giulia

AU - Romandini, Matteo

AU - Silvestrini, Sara

AU - Pedrosi, Maria Elena

AU - Mori, Tommaso

AU - Riga, Alessandro

AU - Kullmer, Ottmar

AU - Sarig, Rachel

AU - Fiorenza, Luca

AU - Giganti, Melchiore

AU - Sorrentino, Rita

AU - Belcastro, Maria Giovanna

AU - Cecchi, Jacopo Moggi

AU - Benazzi, Stefano

PY - 2021

Y1 - 2021

N2 - 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 individualsDiscussion Morphological structure appears instable during the first year of life and acquires an opposite asymmetric bilateral direction between 2 and 6 years of age. This condition has been also documented in adults; when paired with vertical alteration, anterior/posterior asymmetry seems to characterize palate morphology, which is probably due to mechanical factors during the lifespan. Fluctuating asymmetry is predominant in the first period of life due to a plausible relationship with the strength of morphological instability of the masticatory system. Directional asymmetry, on the other hand, shows that the patterning of group-level morphological change might be explained as a functional response to differential inputs (physiological forces, nutritive and non-nutritive habits, para-masticatory activity as well as the development of speech) in different growth stages. This research has implications with respect to medical and evolutionary fields. In medicine, palate morphology should be considered when planning orthodontic and surgical procedures as it could affect the outcome. As far as an evolutionary perspective is concerned the dominance of directional asymmetries in the masticatory system could provide information on dietary and cultural habits as well as pathological conditions in our ancestors.

AB - 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 individualsDiscussion Morphological structure appears instable during the first year of life and acquires an opposite asymmetric bilateral direction between 2 and 6 years of age. This condition has been also documented in adults; when paired with vertical alteration, anterior/posterior asymmetry seems to characterize palate morphology, which is probably due to mechanical factors during the lifespan. Fluctuating asymmetry is predominant in the first period of life due to a plausible relationship with the strength of morphological instability of the masticatory system. Directional asymmetry, on the other hand, shows that the patterning of group-level morphological change might be explained as a functional response to differential inputs (physiological forces, nutritive and non-nutritive habits, para-masticatory activity as well as the development of speech) in different growth stages. This research has implications with respect to medical and evolutionary fields. In medicine, palate morphology should be considered when planning orthodontic and surgical procedures as it could affect the outcome. As far as an evolutionary perspective is concerned the dominance of directional asymmetries in the masticatory system could provide information on dietary and cultural habits as well as pathological conditions in our ancestors.

KW - directional asymmetry

KW - fluctuating asymmetry

KW - ontogeny

KW - palatal arch

KW - NONNUTRITIVE SUCKING HABITS

KW - DENTAL ARCH ASYMMETRY

KW - BILATERAL SYMMETRY

KW - HEAD POSTURE

KW - MORPHOLOGICAL INTEGRATION

KW - DEVELOPMENTAL INSTABILITY

KW - GEOMETRIC MORPHOMETRICS

KW - DECIDUOUS DENTITION

KW - CERVICAL POSTURE

KW - CLASS-I

U2 - 10.1002/ajpa.24293

DO - 10.1002/ajpa.24293

M3 - Journal article

C2 - 33973654

VL - 175

SP - 847

EP - 864

JO - American Journal of Physical Anthropology

JF - American Journal of Physical Anthropology

SN - 0002-9483

IS - 4

ER -