@article {16349,
	title = {A geometric morphometric evaluation of hard and soft tissue profile changes in borderline extraction versus non-extraction patients.},
	journal = {Eur J Orthod},
	volume = {41},
	year = {2019},
	month = {2019 May 24},
	pages = {264-272},
	abstract = {OBJECTIVES: To evaluate the hard tissue and facial profile changes in matched extraction and non-extraction Class I patients by the use of geometric morphometrics.

SUBJECTS AND METHODS: From a parent sample of 542 Class I patients, previously subjected to discriminant analysis, a subsample of 68 borderline cases was obtained, 34 treated with extraction and 34 without extraction of 4 first premolars. Geometric morphometric methods (Procrustes superimposition and Principal Component Analysis) were applied on cephalometric tracings to assess the validity of the discriminant analysis in successfully identifying a morphologically homogeneous group and to evaluate inter- and intra-group skeletal and facial profile shape changes.

RESULTS: No significant pre-treatment shape difference between the two groups was found, thus validating the discriminant analysis. The non-extraction group showed increase in hard tissue facial height (P < 0.001), with slight lower lip retrusion and upper lip protrusion (P = 0.027). The extraction group showed retraction of the hard tissue and facial profile outline (P < 0.001). Permutation tests for post-treatment inter-group differences resulted in P = 0.054 for the soft tissue outline and P = 0.078 for the hard tissue skeletal component.

CONCLUSIONS: The evidence indicates that borderline cases treated with four premolar extractions will exhibit lip retrusion compared to non-extraction treatment.},
	issn = {1460-2210},
	doi = {10.1093/ejo/cjy056},
	author = {Kouli, Afroditi and Papagiannis, Alexandros and Konstantoni, Nikoleta and Halazonetis, Demetrios J and Konstantonis, Dimitrios}
}
