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Three‐dimensional analysis of facial shape and symmetry in twins using laser surface scanning
Author(s) -
Djordjevic J.,
Jadallah M.,
Zhurov A. I.,
Toma A. M.,
Richmond S.
Publication year - 2013
Publication title -
orthodontics and craniofacial research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 55
eISSN - 1601-6343
pISSN - 1601-6335
DOI - 10.1111/ocr.12012
Subject(s) - forehead , procrustes analysis , landmark , facial symmetry , psychology , anatomy , orthodontics , mathematics , geometry , medicine , geography , cartography
Structured Abstract Objectives Three‐dimensional analysis of facial shape and symmetry in twins. Setting and Sample Population Faces of 37 twin pairs [19 monozygotic ( MZ ) and 18 dizygotic (DZ)] were laser scanned at the age of 15 during a follow‐up of the A von L ongitudinal S tudy of P arents and C hildren ( ALSPAC ), S outh W est of E ngland. Material and Methods Facial shape was analysed using two methods: 1) Procrustes analysis of landmark configurations (63 x , y and z coordinates of 21 facial landmarks) and 2) three‐dimensional comparisons of facial surfaces within each twin pair. Monozygotic and DZ twins were compared using ellipsoids representing 95% of the variation in landmark configurations and surface‐based average faces. Facial symmetry was analysed by superimposing the original and mirror facial images. Results Both analyses showed greater similarity of facial shape in MZ twins, with lower third being the least similar. Procrustes analysis did not reveal any significant difference in facial landmark configurations of MZ and DZ twins. The average faces of MZ and DZ males were coincident in the forehead, supraorbital and infraorbital ridges, the bridge of the nose and lower lip. In MZ and DZ females, the eyes, supraorbital and infraorbital ridges, philtrum and lower part of the cheeks were coincident. Zygosity did not seem to influence the amount of facial symmetry. Lower facial third was the most asymmetrical. Conclusion Three‐dimensional analyses revealed differences in facial shapes of MZ and DZ twins. The relative contribution of genetic and environmental factors is different for the upper, middle and lower facial thirds.