Determining normal and abnormal lip shapes at border positions for use as a longitudinal surgical outcome measure H. POPAT*, A. I. ZHUROV*, S. RICHMOND*, D. MARSHALL † & P. L. ROSIN † *Applied Clinical Research and Public Health, School of Dentistry, Cardiff University, Cardiff and † Cardiff School of Computer Science & Informatics, Cardiff University, Cardiff, UK SUMMARY Objective measures of facial movement are important for interventions where surgical repositioning of facial structures can influence soft tissue mobility and include the management of patients with cleft lip, facial nerve palsy and orthognathic surgery. As such, the aim of this study is to present a method for determining the outcome of surgical procedures on lip shape during speech. A control group (CG) of 115 average subjects and 30 patients with a Class 3 malocclusion requiring bimaxillary surgery performed four reproducible verbal utterances during image capture using a non-invasive, three- dimensional (3D) motion scanner (3dMDFace TM Dynamic System). Landmark coordinates around the lips of the 3D facial shells were extracted and subjected to discriminant analysis and principal component analysis to statistically differentiate lip shapes between the CG and the patient group (PG) pre- and post-surgery. Pre-surgically, the PG showed statistically significant differences in lip shape during speech in the lateral and vertical dimensions, preferring a wider, shorter lip shape when compared with the CG for all the utterances. The shape differences normalised towards the CG post-surgery. The method presented utilises pre- existing statistical shape analyses and can be reproduced in the clinical setting to provide a diagnostic and functional outcome tool. In this example, correction of the Class 3 skeletal disproportions appeared to normalise lip shape during speech. KEYWORDS: anatomic landmarks, orthognathic surgical procedures/methods, malocclusion, angle class III/surgery, imaging, three-dimensional/ methods, lip/movement, speech articulation tests Accepted for publication 9 January 2013 Introduction Facial movement and animation have been shown to be an important factor in facial aesthetics (1). As such, an objective measure of facial movement can form a vital consideration in the diagnosis and treat- ment planning of patients with cleft lip undergoing repair/revision and patients planned for orthognathic surgery. Although soft tissue changes following cra- niofacial surgery have traditionally been studied using analyses on the static or resting face shape (2–4), advances in medical imaging technology and associ- ated computer-assisted analyses have now made three-dimensional (3D) quantification of facial move- ment accessible (5). Indeed, objective assessment of facial movement for patients undergoing craniofacial intervention has now been realised. Using non- invasive, video-based tracking systems, research groups have been able to model 3D movements in patients undergoing orthognathic surgery (6). Here, millimetre-diameter, retro-reflective markers were placed onto specific facial landmarks and tracked © 2013 Blackwell Publishing Ltd doi: 10.1111/joor.12037 Journal of Oral Rehabilitation 2013 40; 348--357 Journal of Oral Rehabilitation