An Innovative Assessment of the Dynamics of Facial Movements in Surgically Managed Unilateral Cleft Lip and Palate Using 4D Imaging

Deep Learning-Based Assessment of Lip Symmetry for Patients With Repaired Cleft Lip

ObjectivePost-surgical lip symmetry assessment is a key indicator of cleft repair success. Traditional methods rely on distances between anatomical landmarks, which are impractical for video analysis and overlook texture and appearance. We propose an artificial intelligence (AI) approach to automate this process, analyzing lateral lip morphology for a quantitative symmetry evaluation.DesignWe utilize contrastive learning to quantify lip symmetry by measuring the similarity between the representations of the sides, which is subsequently used to classify the severity of asymmetry. Our model does not require patient images for training. Instead, we introduce dissimilarities in face images from open datasets using two methods: temporal misalignment for video frames and face transformations to simulate lip asymmetry observed in the target population. The model differentiates the left and right image representations to assess asymmetry. We evaluated our model on 146 images of patients with repaired cleft lip.ResultsThe deep learning model trained with face transformations categorized patient images into five asymmetry levels, achieving a weighted accuracy of 75% and a Pearson correlation of 0.31 with medical expert human evaluations. The model utilizing temporal misalignment achieved a weighted accuracy of 69% and a Pearson correlation of 0.27 for the same classification task.ConclusionsWe propose an automated approach for assessing lip asymmetry in patients with repaired cleft lip by transforming facial images of control subjects to train a deep learning model, eliminating manual anatomical landmarks. Our promising results provide a more efficient and objective tool for evaluating surgical outcomes.

Association of Clinical, Biomechanical, and Psychosocial Factors with Smile Dynamics in Unilateral Cleft Lip: A Multicenter Observational Study

OBJECTIVE

To investigate the association between clinical, biomechanical, and psychosocial factors and smiling behavior in individuals with treated unilateral cleft lip with or without cleft palate (UCL ± P) compared to non-cleft controls.

DESIGN

Multicenter observational study in New Zealand.

PARTICIPANTS

Individuals aged ≥15 (N = 42) comprised 2 study groups: a UCL ± P group (N = 21) and a non-cleft control group (N = 21).

METHODS

Participants viewed an amusing video while their facial expressions were recorded. Smile features were automatically detected via software. A clinical outcome, nasolabial esthetics, was scored using the Asher-McDade system. Perioral biomechanical properties were measured via myotonometry. Smile Esthetics-related Quality of Life (SERQoL), Orofacial Esthetics Scale (OES), and personality (IPIP-NEO-60) questionnaires were completed.

RESULTS

Smile features and personality traits did not differ between the groups. Participants with UCL ± P exhibited higher stiffness (+44.2%; Cohen's d = 1.6) and tone (+22.6%; Cohen's d = 1.9) at the cleft scar site, and higher decrement (or lower elasticity, +8.5%; Cohen's d = 0.8) adjacent to the scar. Nasolabial esthetics and elasticity of the scar correlated with the duration of smiles and relative smile time (-0.50 < R < -0.44; p < .05). Participants in the UCL ± P group had lower scores for the OES and higher impacts on SERQoL for social contacts and dental self-confidence.

CONCLUSIONS

Adolescents and adults with UCL ± P exhibit similar smile behavior as their cleft-free peers-at least in non-social settings. Nasolabial esthetics and perioral biomechanical properties are associated with propensity to smile. UCL ± P is negatively associated with smile-related quality of life and an individual's perception of their facial appearance.

The Correlation Between Static and Dynamic Facial Asymmetry in Unilateral Cleft Lip and Palate

OBJECTIVE

Assess the relationship between static and dynamic facial asymmetry in unilateral cleft lip and palate during maximum smile.

DESIGN

Retrospective cross-sectional study.

SETTING

Multidisciplinary dentofacial planning clinic.

PARTICIPANTS

Thirty-one surgically managed non-syndromic unilateral cleft lip and palate patients between the ages of 13 to 17 years.

MATERIALS AND METHODS

Dynamic three-dimensional (3D) facial images (four-dimensional [4D]) throughout the course of a maximum smile were captured using video stereophotogrammetry at a rate of 60 frames per second, which generated 180 3D images/expression. A generic facial mesh containing more than 7000 vertices was superimposed onto the 3D facial images to quantify and track facial asymmetry throughout the captured sequence. Partial ordinary Procrustes analysis was utilized to calculate an asymmetry score at the rest position, maximum smile, and at the point of maximum mathematical asymmetry. The relationships between the asymmetry at rest and the asymmetry at the point of maximum smile (static 3D), and the maximum mathematical asymmetry (dynamic 4D) were evaluated.

RESULTS

Asymmetry scores were higher at maximum smile than at rest. Maximum mathematical asymmetry was observed in most cases during the relaxation phase. Static asymmetry at rest and maximum smile was strongly correlated with the maximum mathematical asymmetry (r = 0.941, P < .001).

CONCLUSIONS

Static 3D asymmetry at both rest and maximum smile are strongly correlated with dynamic 4D facial asymmetry. The use of 4D imaging, combined with generic mesh conformation and dense correspondence analysis, provides a valid objective measure of facial asymmetry.

What comes first: teeth or face? Recommendations for an interdisciplinary collaboration between facial esthetic surgery and dentistry

OBJECTIVE

The aim of the present study was to provide recommendations in order to facilitate communication between dental professionals and surgeons who are collaborating in the field of dentofacial esthetics.

CLINICAL CONSIDERATIONS

Smile esthetics are beyond the scope, both of the surgeons who are collaborating with facial esthetics and of the dentists, as a wide range of treatment options from both sides is available. It can be difficult for the surgeon or the dentist that first comes in contact with the patient to conduct an individualized global treatment plan, in order to find out how the various phases of the treatment can be sequenced, as a workflow for an efficient interaction between facial surgery and dentistry still does not exist in the scientific literature.

CONCLUSIONS

Facial cosmetic procedures and dental treatment have to be planned as individual elements of the whole dentofacial esthetic rehabilitation. The treatment has to be initiated with the design of the smile and the intraoral mock-up, followed by the required surgical interventions, and to be finished with the delivery of the definitive dental restoration.

CLINICAL SIGNIFICANCE

Dentofacial esthetics require comprehensive communication between surgeons and dentists. Following the proposed recommendations, an individualized interdisciplinary treatment plan can be conducted, defining the role of each specialty.

Enhancing Philtrum Morphology Using Fat Grafting Combined with Percutaneous Rigottomy in Repaired Unilateral Cleft Lip

BACKGROUND

Improving the philtrum morphology of patients with a secondary cleft lip deformity has been a challenge in cleft care. Combining fat grafting with percutaneous rigottomy has been advocated for treatment of volumetric deficiency associated with a scarred recipient site. This study assessed the outcome of synchronous fat grafting and rigottomy for improvement of cleft philtrum morphology.

METHODS

Consecutive young adult patients ( n = 13) with a repaired unilateral cleft lip who underwent fat grafting combined with rigottomy expansion technique for enhancement of philtrum morphology were included. Preoperative and postoperative three-dimensional facial models were used for three-dimensional morphometric analyses including philtrum height, projection, and volume parameters. Lip scar was qualitatively judged by a panel composed by two blinded external plastic surgeons using a 10-point visual analogue scale.

RESULTS

Three-dimensional morphometric analysis revealed a significant (all P < 0.05) postoperative increase of the lip height-related measurements for cleft philtrum height, noncleft philtrum height, and central lip length parameters, with no difference ( P > 0.05) between cleft and noncleft sides. The postoperative three-dimensional projection of the philtral ridges was significantly ( P < 0.001) larger in cleft (1.01 ± 0.43 mm) than in noncleft sides (0.51 ± 0.42 mm). The average philtrum volume change was 1.01 ± 0.68 cm 3 , with an average percentage fat graft retention of 43.36% ± 11.35%. The panel assessment revealed significant ( P < 0.001) postoperative scar enhancement for the qualitative rating scale, with mean preoperative and postoperative scores of 6.69 ± 0.93 and 7.88 ± 1.14, respectively.

CONCLUSION

Synchronous fat grafting and rigottomy improved philtrum length, projection, and volume and lip scar in patients with repaired unilateral cleft lip.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Longitudinal Three-Dimensional Stereophotogrammetric Growth Analysis in Infants with Unilateral Cleft Lip and Palate from 3 to 12 Months of Age

This longitudinal study aimed to evaluate facial growth and soft tissue changes in infants with complete unilateral cleft lip, alveolus, and palate (CUCLAP) at ages 3, 9, and 12 months. Using 3D images of 22 CUCLAP infants, average faces and distance maps for the entire face and specific regions were created. Color-coded maps highlighted more significant soft tissue changes from 3 to 9 months than from 9 to 12 months. The first interval showed substantial growth in the entire face, particularly in the forehead, eyes, lower lip, chin, and cheeks (p < 0.001), while the second interval exhibited no significant growth. This study provides insights into facial soft tissue growth in CUCLAP infants during critical developmental stages, emphasizing substantial improvements between 3 and 9 months, mainly in the chin, lower lip, and forehead. However, uneven growth occurred in the upper lip, philtrum, and nostrils throughout both intervals, with an overall decline in growth from 9 to 12 months. These findings underscore the dynamic nature of soft tissue growth in CUCLAP patients, highlighting the need to consider these patterns in treatment planning. Future research should explore the underlying factors and develop customized treatment interventions for enhanced facial aesthetics and function in this population.

The impact of orthodontic-surgical treatment on facial expressions-a four-dimensional clinical trial

OBJECTIVE

The objective of this clinical trial was to compare facial expressions (magnitude, shape change, time, and symmetry) before (T0) and after (T1) orthognathic surgery by implementing a novel method of four-dimensional (4D) motion capture analysis, known as videostereophotogrammetry, in orthodontics.

METHODS

This prospective, single-centre, single-arm trial included a total of 26 adult patients (mean age 28.4 years; skeletal class II: n = 13, skeletal class III: n = 13) with indication for orthodontic-surgical treatment. Two reproducible facial expressions (maximum smile, lip purse) were captured at T0 and T1 by videostereophotogrammetry as 4D face scan. The magnitude, shape change, symmetry, and time of the facial movements were analysed. The motion changes were analysed in dependence of skeletal class and surgical movements.

RESULTS

4D motion capture analysis was feasible in all cases. The magnitude of the expression maximum smile increased from 15.24 to 17.27 mm (p = 0.002), while that of the expression lip purse decreased from 9.34 to 8.31 mm (p = 0.01). Shape change, symmetry, and time of the facial movements did not differ significantly pre- and postsurgical. The changes in facial movements following orthodontic-surgical treatment were observed independently of skeletal class and surgical movements.

CONCLUSIONS

Orthodontic-surgical treatment not only affects static soft tissue but also soft tissue dynamics while smiling or lip pursing.

CLINICAL RELEVANCE

To achieve comprehensive orthodontic treatment plans, the integration of facial dynamics via videostereophotogrammetry provides a promising approach in diagnostics.

TRIAL REGISTRATION NUMBER

DRKS00017206.

An innovative analysis of nasolabial dynamics of surgically managed adult patients with unilateral cleft lip and palate using 3D facial motion capture

AIM

To compare dynamic nasolabial movement between end-of-treatment cleft and a matched non-cleft group in adult patients.

MATERIALS AND METHODS

Thirteen treated adult participants with unilateral cleft lip and palate had images taken using a facial motion capture system performing a maximum smile. Seventeen landmarks were automatically tracked. For each landmark pair, on either side of the midline, changes in the x, y, and z directions were used to analyze the magnitude of displacement and path of motion. An asymmetry score was developed at rest, mid-smile, and maximum smile to assess the shape of the mouth and/or nose.

RESULTS

At maximum smile, displacement of right and left cheilion was clinically and statistically (p < 0.05) less in the cleft group. The lip asymmetry score was greater (p < 0.05) at each time point in the cleft group using the clinical midline. Using Procrustes superimposition, the differences were significant (p < 0.05) only at rest and mid-smile. The alar bases were displaced significantly less (p < 0.05) in the z direction in the cleft group. The asymmetry score of the alar base was significantly higher using the clinical midline than using Procrustes superimposition in patients with cleft conditions (p < 0.001). In the cleft group, at maximum smile, the right and left cristae philter moved significantly less (p < 0.05) in the x and z directions.

CONCLUSIONS

There was an increase in asymmetry score of the corners of the mouth and alar bases from rest to maximum smile. The lips were similar in shape but oriented differently in the faces of patients with cleft conditions than in individuals without those conditions.

3D assessment of the nasolabial region in cleft models comparing an intraoral and a facial scanner to a validated baseline

We aimed to validate the metric accuracy of a 3-dimensional (3D) facial scanner (FS) and an intraoral scanner (IOS) in capturing the nasolabial region in ex vivo unilateral cleft lip and palate (UCLP) models. The nasolabial region of 10 UCLP models was scanned using a 3D FS as well as an IOS and a previously validated stationary 3D scanner as a reference. Intraoral scan was performed directly on the UCLP models. In order to apply the FS on the models, they were embedded in a 3D printed sample face. Both test groups were aligned to the reference by applying a section-based best-fit algorithm. Subsequent analysis of the metric deviation from the reference was performed with a 3D analysis tool. Mean distance and integrated distance served as main parameters for surface and volume comparison. Point comparison served as an additional parameter. Statistical analysis was carried out using t-test for unconnected samples. Considering mean distance and integrated distance as main parameters for 3D evaluation of the scanner's accuracy, FS and IOS differ significantly in their metric precision in scanning the cleft model compared to the reference. The IOS proved to be significantly more accurate than the FS compared to the previously described stationary 3D scanner as reference and validated baseline. Further validation of the tested IOS and FS for 3D assessment of the nasolabial region is presented by adding the previously validated ATOS III Triple Scan blue light scanner as a reference. The IOS shows, compared to a validated baseline scan, significantly higher metric precision in experimental cleft model scanning. The collected data provides a basis for clinical application of the IOS for 3D assessment of the nasolabial region.

Static and Motion Facial Analysis for Craniofacial Assessment and Diagnosing Diseases

Deviation from a normal facial shape and symmetry can arise from numerous sources, including physical injury and congenital birth defects. Such abnormalities can have important aesthetic and functional consequences. Furthermore, in clinical genetics distinctive facial appearances are often associated with clinical or genetic diagnoses; the recognition of a characteristic facial appearance can substantially narrow the search space of potential diagnoses for the clinician. Unusual patterns of facial movement and expression can indicate disturbances to normal mechanical functioning or emotional affect. Computational analyses of static and moving 2D and 3D images can serve clinicians and researchers by detecting and describing facial structural, mechanical, and affective abnormalities objectively. In this review we survey traditional and emerging methods of facial analysis, including statistical shape modeling, syndrome classification, modeling clinical face phenotype spaces, and analysis of facial motion and affect. Expected final online publication date for the Annual Review of Biomedical Data Science, Volume 5 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Three-Dimensional Motion Capture of a Smile in Repaired Unilateral Cleft Lip: What's Our Vector, Victor?

INTRODUCTION

Following surgical repair, patients with unilateral cleft lip (UCL) exhibit dynamic asymmetry during facial expressions compared to healthy individuals. Previous studies using Euclidean distances to describe this asymmetry fail to take the direction of the movement into account. The aim of this study is to compare differences in participants with UCL and controls using analysis of motion vectors during facial expressions.

METHODS

In this cross-sectional study, twenty-six pediatric participants were recruited: 13 participants with repaired left UCL and 13 participants with no craniofacial diagnosis. Participants were recorded performing a maximal smile by a 4D stereophotogrammetric system. Phases of the smile were divided into closed lip and open lip smiles. Ten regions of interest were analyzed: subnasal area, upper lip, lower lip, oral commissure, and ala on both sides. The motion vectors were calculated and vector magnitude and direction for each region was compared.

RESULTS

Between cleft and control groups, the differences in vector direction were greater than the magnitude differences. Significant differences in vector direction were identified at both oral commissures in the closed lip smile; and at the oral commissure, subnasal, upper lip, and lower lip regions during open lip smile.

CONCLUSIONS

Vector analysis demonstrated significant movement asymmetry during facial animation in participants following UCL repair, not previously identified when analyzing magnitude of skin displacement.

The Validation of an Innovative Method for 3D Capture and Analysis of the Nasolabial Region in Cleft Cases

Objective:

To validate a newly developed method for capturing 3-dimensional (3D) images of the nasolabial region for assessing upper lip scarring and asymmetry in surgically managed unilateral cleft lip and palate (UCLP) cases.

Design:

Validation study, single cohort.

Materials and Methods:

Eighteen surgically managed UCLP cases were recruited, the nasolabial region of each face was scanned using an intraoral scanner (IOS) to produce 3D images. The images were manually segmented to allow the calculation of surface area of the scar and upper lip asymmetry. Five professionals and 5 lay assessors subjectively evaluated the same images and graded the upper lip scarring and asymmetry at 2 separate occasions. The relationship between the subjective and objective assessments was evaluated.

Results:

Moderate correlation was found between subjective and objective evaluations of the upper lip scarring and total asymmetry. The captured 3D images were of good quality for the objective measurements of lip asymmetry and residual scarring. Moderate to strong correlations were detected between the 2 panels (T ranging between 0.5 and 0.9) with no significant difference (P > .05) in the mean score of the subjectively evaluated parameters.

Conclusion:

The IOS is a useful tool for the capture of the nasolabial morphology. The captured 3D images are a reliable source for measuring lip asymmetry and scar surface area. The method has sufficient validity for routine clinical use and for objective outcome measures of the surgical repair of cleft lip.

The effect of resting morphological lip shape during lip movement: A three-dimensional motion analysis study

Purpose

The aim of this study was to determine the influence of different morphological lip shape during lip movement.

Method

A sample of 80 individuals with three-dimensional facial images at rest and during speech were recorded. Subjects were asked to pronounce four bilabial words in a relaxed manner and scanned using the 3dMDFace™ Dynamic System at 48 frames per second. Six lip landmarks were identified at rest and the landmark displacement vectors for the frame of maximal lip movement for all six visemes were recorded. Principal component analysis was applied to isolate relationship between lip traits and their registered coordinates. Eight specific resting morphological lip traits were identified for each individual. The principal component (PC) scores for each viseme were labelled by lip morphological trait and were graphically visualized as ellipses to discriminate any differences in lip movement.

Results

The first five PCs accounted for up to 95% of the total variance in lip shape during movement, with PC1 accounting for at least 38%. There was no clear discrimination between PC1, PC2 and PC3 for any of the resting morphological lip traits.

Conclusion

Lip shapes during movement are more uniform between individuals and resting morphological lip shape does not influence movement of the lips.