Modeling facial movement: II. A dynamic analysis of differences caused by orthognathic surgery

Abstract

Purpose-The purpose of this study was to determine the facial movement characteristics of patients who underwent orthognathic surgery. The specific aims were to determine the presurgery versus postsurgery differences in facial movements; to determine whether the presurgery facial movements were similar among patients with different dentofacial deformities; and to determine whether patients have a more similar post-than presurgery dentofacial morphology and soft tissue movement. The hypothesis was that there are differences between the pre-and postsurgery facial movements.Patients and Methods-The sample consisted of 19 patients (11 women, 8 men) with a mean age of 20.6 years (SD ± 8.34). Facial movement and lateral cephalometric data were collected at presurgery, and at 6 and 12 months postsurgery. Measures of the facial skeletal differences were made from lateral cephalometric radiographs and facial movements were recorded by a videobased tracking system. Descriptive and inferential statistics were performed on principal component scores generated from the movement data. A linear mixed-effects model was used to test for significant differences in movement.Results-Differences were found between the presurgery and 12-month postsurgery visits for the instructed smile, lip purse, eye closure, grimace, and mouth opening movements as well as the natural smile. Also, there were significant differences at presurgery among the dentofacial groups for the lip purse movement but no differences were found at postsurgery for any of the movements.Conclusion-These findings suggest that facial movements are effected by skeletal malocclusion and orthognathic surgical procedures.Facial appearance and our expressive behaviors have a major impact on how we are perceived and how others in society perceive us. For an individual with a facial functional impairment and/or disfigurement, however, these interactions and associated perceptions Early methods to evaluate facial impairments were based on 2-dimensional (2D) measures; however, because of a lack of information in all planes of space and a resultant oversimplification of the findings, 3-dimensional (3D) measures are now preferred. 1 Currently, 3D measures generated from video-based tracking techniques are regarded as the most valid approach to record and evaluate facial movements. [2][3][4][5][6][7][8][9][10] For the correction of facial disfigurements caused by dentofacial deformities, the standard procedure is orthognathic surgery. This type of surgery is reasonably predictable and results in a harmonization of facial skeletal structures. 11-13 Much less is known, however, about the pre-and postsurgery facial soft tissue function in orthognathic surgery patients, and whether impairments in movement exist in association with the skeletal deformity. Previous research has suggested that patients with severe skeletal deformities have impairments in movement outside the range of that seen in unaffected individuals. 9 If functional impairments exist presurgically in orthognat...

Avaliação estética da face em indivíduos com deformidades dentofaciais

“…We suggest a new study with a larger sample to confirm this trend. In addition, the literature does not show a relationship between DFD and expression wrinkles; however, researches have shown that DFD individuals had difficulties to perform facial mimics in the preoperative period 35,36 .…”

Recent Photography Trends in Orthodontics

“…Using of this method is widespread in the smile position rather than the rest position. 27 Schabel et al 28 reported that digital videography method gives us a lot of information for assessing the dynamic properties of smile, but the standard digital photography method is still sufficient for evaluation of smiles after treatment.…”

The Fathers of Italian Histology

“…This morphology is never static, but it continuously acts and reacts to environmental and internal stimuli. The face plays a major role in social communication and interaction (Hennessy et al, 2005;Johnson and Sandy, 2003;Matoula and Pancherz, 2006;Nooreyazdan et al, 2004;Tarantili et al, 2005), and it carries information that allows the identification of a single person (DeCarlo et al, 1998;Fraser et al, 2003;Shi et al, 2006).Functional impairments in facial expression may be caused by central nervous system diseases (Parkinson disease), facial nerve paralysis, dentofacial deformities and scars, congenital anomalies like cleft lip (Linstrom, 2002;Linstrom et al, 2002;Mishima et al, 2004;Nooreyazdan et al, 2004;Tarantili et al, 2005;Trotman et al, 1998a; Wachtmann et al, 2001), and may provoke serious alterations in the quality of life of the patients. Additionally, modifications in facial motion had been reported in patients affected by several psychiatric disorders (Mergl et al, 2005).…”

“…In the past, static (photographic) and dynamic (cinematographic) two-dimensional systems had been devised and applied in several clinical contests (Linstrom, 2002;Linstrom et al, 2002;Tarantili et al, 2005; Wachtmann et al, 2001). Unfortunately, facial motion is a complex activity that develops in all three spatial planes; two-dimensional recordings can significantly underestimate facial movements (Frey et al, 1999;Gross et al, 1996;Nooreyazdan et al, 2004).Currently, various three-dimensional motion analyzers allow a non-invasive quantitative assessment of soft tissue facial movements without interfering with the subject, and details about instruments, measurement protocols and data analysis have been reported (Frey et al, 1999;Giovanoli et al, 2003;Johnston et al, 2003;Mergl et al, 2005;Mishima et al, 2004;Nooreyazdan et al, 2004;Weeden et al, 2001).Previous investigations developed standardized sequences of facial animations, but only symmetric movements had been studied so far. In contrast, asymmetric motions could allow a better assessment of unilateral facial palsy, for instance after facial nerve lesion.…”

“…During the execution of the movement, for any TV camera special software recognized the coordinates of the center of gravity of 21 passive markers positioned on facial landmarks (Figure 1). Subsequently, all the coordinates were converted to real metric data, and a set of x-, y-, z-coordinates for each landmark in each frame that constituted each expression was obtained.For each subject, 2-mm reflective markers were located on the following 21 anatomical landmarks Nooreyazdan et al, 2004): tr, trichion; n, nasion; prn, pronasale; ls, labiale superius; sl, sublabiale; pg, pogonion; sci, right and left superciliare; ex, right and left exocanthion; or, right and left orbitale; ac, right and left nasal alar crest; ch, right and left cheilion; li, right and left lower lip points halfway between cheilion and sublabiale; t, right and left tragion; v, vertex (Figure 1). Markers' positions were carefully controlled to avoid any interference with facial movements; biadhesive plaster was used to position the markers on the skin.…”