Dear Andrea: Here are some responses to your numbered questions:
1) Do you mean capturing landmark data directly from the face using a digitizing instrument or from data that has been captured using some imaging technique? We landmark data in 2-D and 3-D from patients and volunteers routinely, after grabbing the appropriate image(s). 2) By human face variation, what are you referring to more precisely e.g. variation due to age, sex, ethnicity, etc? There are many papers in the dental and orthodontic literature that have looked at facial and craniofacial heterogeneity. Question 3) Parts b and c are the most interesting. Our data, as well as previous studies, are beginning to show that the human face is less well developed on the left side, most often. The (patho)-etiology remains incompletely understood but may be associated with contra-lateral innervation of facial muscles (and their response to negative emotions) or perhaps differences in venous circulation (an idea that I suggested based on the fact that circulatory asymmetry is encoded genetically and that a right shift occurs during human development). So if you choose the right side of the face, the chimera will look more like the actual face and it will have a slightly decreased amount of FA. Choosing the left side will produce a different result. So, in my limited experience, I might be inclined to say that it does not make sense to use just one side of the human face for statistical analyses. I might add that we have developed a non-surgical orthodontic device that improves, corrects or enhances dentofacial symmetry in non-growing adults. www.homeoblock.com. Sincerely, Dr. G. Dave Singh DDSc PhD BDS www.morphostudio.com References: Anderson NK, Evans CA, Giddon DB. Comparison of perceptions of computer-animated left- and right-facing profiles. J Prosthodont. 1999;8(2):72-9. Singh GD, Diaz J, Busquets-Vaello C, Belfor TR. Soft tissue facial changes following treatment with a removable orthodontic appliance in adults. Functional Orthod., 21(3), 18-23, 2004. Belfor TR and Singh GD. Developing dental arch symmetry using the Homeoblock device. Int J Orthod. 15(3), 27-30, 2004. Belfor TR and Singh GD. Developing facial symmetry using an intra-oral device. J. Cosmetic Dent. 20(2), 76-80, 2004. -- Replies will be sent to the list. For more information visit http://www.morphometrics.org
