Toward 3D facial analysis for recognizing Mendelian causes of autism spectrum disorder.

Recognizing Mendelian causes is crucial in molecular diagnostics and counseling for patients with autism spectrum disorder (ASD). We explored facial dysmorphism and facial asymmetry in relation to genetic causes in ASD patients and studied the potential of objective facial phenotyping in discriminating between Mendelian and multifactorial ASD. In a cohort of 152 ASD patients, 3D facial images were used to calculate three metrics: a computational dysmorphism score, a computational asymmetry score, and an expert dysmorphism score. High scores for each of the three metrics were associated with Mendelian causes of ASD. The computational dysmorphism score showed a significant correlation with the average expert dysmorphism score. However, in some patients, different dysmorphism aspects were captured making the metrics potentially complementary. The computational dysmorphism and asymmetry scores both enhanced the individual expert dysmorphism scores in differentiating Mendelian from non-Mendelian cases. Furthermore, the computational asymmetry score enhanced the average expert opinion in predicting a Mendelian cause. By design, our study does not allow to draw conclusions on the actual point-of-care use of 3D facial analysis. Nevertheless, 3D morphometric analysis is promising for developing clinical dysmorphology applications in diagnostics and training.

Botulinum toxin treatment for hemifacial spasm: harmonising neurological and aesthetic outcomes.

Hemifacial spasm (HFS) represents a challenging cranial movement disorder primarily affecting the facial nerve innervated muscles, with significant prevalence among Asians. Botulinum toxin type A (BoNT/A) injections, established as a primary therapeutic intervention since FDA approval, offer considerable effectiveness in alleviating spasms, albeit accompanied by challenges such as temporary effects and potential adverse events including facial asymmetry. This comprehensive review underscores the crucial need for harmonising neurological benefits and aesthetic outcomes in HFS management. The discussion delves into the interplay between facial aesthetics and neurological objectives in BoNT/A injections, emphasising precise techniques, dosages, and site considerations. Distinct aspects in neurological and aesthetic domains are also examined, including detailing the targeted muscles and injection methodologies for optimal therapeutic and aesthetic results. Importantly, evidence regarding various BoNT/A formulations, recommendations, and reconstitution guidelines in both neurology and aesthetics contexts are provided, along with a schematic approach outlining the stepwise process for BoNT/A injection in HFS treatment, addressing critical areas such as orbicularis oculi muscle sites, eyebrow correction strategies, mid- and lower-face considerations, contralateral injection sites, and post-injection follow-up and complication management. By highlighting the culmination of neurological efficacy and facial esthetics in BoNT/A treatment for HFS patients, this review proposes a holistic paradigm to achieve balanced symptomatic relief and natural aesthetic expression, ultimately enhancing quality of life for individuals grappling with HFS.

Facial asymmetry outcome of orthognathic surgery in mild craniofacial microsomia compared to non-syndromic class II asymmetry.

OBJECTIVES: To compare the facial asymmetry after bimaxillary surgery between mild craniofacial microsomia (CFM) and non-syndromic class II asymmetry. MATERIALS AND METHODS: Cone-beam computed tomography scans of adults with Pruzansky-Kaban types I and IIA CFM (CFM groups, n = 20), non-syndromic skeletal class II asymmetry (Class II group, n = 20), and normal controls (control group, n = 20) were compared. The area asymmetry of lower face and jaw bones was quantified. Landmark-based method was used to evaluate the lower facial asymmetry regarding midline, cants, and contour. RESULTS: There were no significant postoperative differences in the hemi-facial and hemi-jaw area asymmetry between CFM and Class II groups, both of which were significantly larger than the control group. No significant difference was found in the midline deviation and lip and occlusal cants between CFM and Class II groups. The vertical contour asymmetry in CFM group became significantly larger than Class II group. Compared to the control group, the deviation of pronasale, subnasale, and soft-tissue menton, lip and occlusal cants, and sagittal and vertical contour asymmetry in CFM group were significantly larger, as were the deviation of subnasale and soft-tissue menton and vertical contour asymmetry in Class II group. CONCLUSIONS: The vertical contour asymmetry of mild CFM was significantly larger than non-CFM class II after surgery, while the area asymmetry, midline deviation, cants, and sagittal contour asymmetry of lower face showed no significant difference. CLINICAL RELEVANCE: Be aware that correcting vertical asymmetry of contour, lip, and dentition in CFM is still challenging.

Evaluation of maxillary arch symmetry in cleft patients undergoing orthodontic treatment: a comparative study.

OBJECTIVE: Patients with a cleft require structured procedures to achieve feasible treatment results. Since many treatment protocols coexist without being superior to one another, this study investigated the Saarland University Hospital treatment concept for patients with unilateral and bilateral clefts to evaluate its effects upon dental arch dimensions until the early mixed dentition. MATERIAL AND METHODS: Digitized plaster models were used for data collection. Records of 83 patients (Cleft n = 41 [UCLP n = 28, BCLP n = 13], Non-Cleft Control n = 42) comprised 249 casts. The evaluation included established procedures for measurements of edentulous and dentate jaws. Statistics included Shapiro-Wilk, Friedmann, Wilcoxon and Mann-Whitney-U-Tests for the casts. The level of significance was set at p < 0.05. RESULTS: The cast analysis showed an approximation of arch dimensions towards those of age-matched patients without a cleft until early mixed dentition. The mean values of patients with and without cleft lip and palate were almost indistinguishable when compared in primary and/or early mixed dentition. CONCLUSIONS: The evaluated treatment concept leads to feasible outcomes regarding dental arches in patients with unilateral and bilateral clefts compared to an age-matched non-cleft control. CLINICAL RELEVANCE: The evaluated treatment concept leads to favorable outcomes until early mixed dentition.

Site and severity of facial asymmetry after bimaxillary surgery for class III deformity: a case-control study.

OBJECTIVES: The study aimed (1) to evaluate the site and severity of facial asymmetry in Class III patients before and after bimaxillary surgery, and (2) to identify the influence of initial severity and positional jaw asymmetry on residual facial asymmetry. MATERIALS AND METHODS: Preoperative and postoperative cone-beam computed tomography of 65 patients with Class III facial asymmetry who underwent bimaxillary surgery were evaluated. Five midline and 14 paramedian facial soft tissue landmarks were identified to assess facial asymmetry. The outcomes were compared to a control group consisting of 30 age- and gender-matched Class I subjects. The postoperative positional jaw asymmetry (i.e., shift, roll, yaw) of each osteotomy segment (maxilla, mandible, chin, ramus) was also measured. RESULTS: Before surgery, the asymmetry was more severe at the chin, middle and lower contour. Bimaxillary surgery effectively corrected facial asymmetry, particularly in achieving normalization of chin deviation. However, significant asymmetry persisted postoperatively in the middle and lower contour (p < 0.001 and p < 0.01, respectively), which was affected by the positional ramus asymmetry in the roll and shift. CONCLUSIONS: Deviation of the chin, middle and lower contour contributed significantly to overall facial asymmetry in Class III asymmetry. Despite normalization of the chin deviation after bimaxillary surgery, asymmetry persisted at the middle and lower contour, primarily as the result of insufficient correction of the positional ramus asymmetry. CLINICAL RELEVANCE: Understanding the residual asymmetry after bimaxillary surgery is important for minimizing deviation and optimizing the surgical planning for its correction.

Establishment of the mid-sagittal reference plane for three-dimensional assessment of facial asymmetry: a systematic review : Establishment of the mid-sagittal reference plane: a systematic review.

OBJECTIVE: To systematically review the literature for mid-sagittal plane establishment approaches to identify the most effective method for constructing the mid-sagittal plane for the evaluation of facial asymmetry. MATERIALS AND METHODS: Six electronic databases (PubMed, Medline (via Ovid), EMBASE (via Ovid), Cochrane Library, Web of Science, and Scopus) and grey literature were searched for the studies that computed the mid-sagittal reference plane three-dimensionally, using a combination of MeSH terms and keywords. The methodological quality and the level of evidence for the included studies were analyzed using QUADAS-2 and GRADE, respectively. RESULTS: The preliminary search yielded 6746 records, of which 42 articles that met the predefined inclusion criteria were included in the final analysis. All the included articles reported the construction of the mid-sagittal reference plane (MSP) using varied methods. The risk of bias and concerns regarding the applicability of the included studies were judged to be 'low'. The level of evidence was determined to be 'low' for the effectiveness of the technique and 'moderate' for the ease of clinical applicability. CONCLUSION: Despite methodological heterogeneity, this review substantiates the comparable efficacy of cephalometric and morphometric MSP construction methods. A fully automated morphometric MSP holds promise as a viable option for routine clinical use. Nevertheless, future prospective studies with an emphasis on the impact, accuracy, and clinical applicability of MSP construction techniques in cases of facial asymmetry are required. CLINICAL RELEVANCE: The present review will assist clinicians in selecting the most suitable method for MSP construction, leading to improved treatment planning and ultimately more favorable treatment outcomes.

Differential outcomes of jaw bone position after surgical-orthodontic treatment in three types of skeletal Class III asymmetry patients.

BACKGROUND/PURPOSE: Facial asymmetry is common in Class III patients requiring orthognathic surgery. This study aimed to analyze jaw bone position after surgical-orthodontic treatment in three types of skeletal Class III asymmetry patients. METHODS: The retrospective study included 30 Class III patients who underwent surgical-orthodontic treatment comprising LeFort I osteotomy and bilateral sagittal split osteotomy (BSSO) without genioplasty. Cone-beam computed tomography (CBCT) images obtained before surgery (T1) and after post-surgical orthodontic treatment (T2) were superimposed with voxel-based registration. Patients were classified into three groups based on T1 CBCT scans. Groups 1 and 2 exhibited menton and ramus deviated to the same side. Menton deviation was larger than ramus width asymmetry in group 1, while the reverse was true for group 2. Group 3 had menton deviation contralateral to the side with greater ramus width. RESULTS: Menton deviation after treatment was improved in all groups. Ramus width asymmetry and coronal ramus angle difference decreased in groups 1 and 2. Neither improvement nor deterioration of ramus width asymmetry was noted for group 3. Comparing to groups 1 and 2, group 3 had greater roll and yaw rotations of distal segment, more upward pitch of proximal segment on chin deviation side, and largest inward yaw as well as backward translation of proximal segment on non-deviation side. CONCLUSION: The positional changes of osteotomy segments differed among three types of mandibular asymmetry. Special attention should be given to the atypical mandibular asymmetry with mandibular body and ramus deviating to opposite directions during surgical correction of jaw deflection.

The accuracy and reliability of different midsagittal planes in the symmetry assessment using cone-beam computed tomography.

Symmetry is an essential component of esthetic assessment. Accurate assessment of facial symmetry is critical to the treatment plan of orthognathic surgery and orthodontic treatment. However, there is no internationally accepted midsagittal plane (MSP) for orthodontists and orthognathic surgeons. The purpose of this study was to explore a clinically friendly MSP, which is more accurate and reliable than what is commonly used in symmetry assessment. Forty patients with symmetric craniofacial structures were analyzed on cone-beam computed tomography (CBCT) scans. The CBCT data were exported to the Simplant Pro software to build four reference planes that were constructed by nasion (N), basion (Ba), sella (S), odontoid (Dent), or incisive foramen (IF). A total of 31 landmarks were located to determine which reference plane is the most optimal MSP by comparing the asymmetry index (AI). The mean value of AI showed a significant difference (p < 0.05) among four reference planes. Also, the mean value of AI for all landmarks showed that Plane 2 (consisting of N, Ba, and IF) and Plane 4 (consisting of N, IF, and Dent) were more accurate and stable. In conclusion, the MSP consisting of N, Dent, and IF shows more accuracy and reliability than the other planes. Further, it is more clinically friendly because of its significant advantage in landmarking.

Changes in 3-Dimensional Measurements of Masseter Muscle After Orthognathic Surgery in Patients with Facial Asymmetry.

OBJECTIVE: The aim of this study was to quantitatively evaluate morphological and volumetric changes in the masseter muscle using 3-dimensional analysis of facial asymmetry patients and to identify factors influencing these changes before and after orthognathic surgery. METHODS: [Reviewer1 (2)]A single-center retrospective cohort study was conducted on twenty-two patients with deviation of the chin > 4 mm. Masseter muscle volume and morphology were measured at different periods during long-term follow-up (mean 15 ± 3.2 months). Factors related to changes in masseter muscle cross-sectional area and volume analyzed were also analyzed. RESULTS: [Reviewer1 (2) and (9)]The volume and cross-sectional area of the masseter muscle on the non-deviated side reduced by 13.5% (P < 0.05) and 16.4% (P < 0.05), respectively, after orthognathic surgery. The length of the masseter muscle increased by 13.9% on the deviated side (P < .05) but decreased by 11.7% on the non-deviated side (P < 0.05). The width decreased on the deviated side from T1 to T2 (13.51 ± 2.09 mm vs. 12.04 ± 1.39 mm), but the non-deviated side showed an opposite tendency (10.81 ± 1.31 mm vs. 12.69 ± 2.37 mm). The difference in masseter muscle length and width between the two sides significantly reduced after surgery (P < 0.05). There was a noticeable decrease in the asymmetry in the muscle in proportion to the degree of the occlusal plane angle. CONCLUSION: Masseter muscle asymmetry exists in patients with facial asymmetry, but it could be improved with maxilla-mandible correction. Atrophy of the masseter muscle after orthognathic surgery was greater in patients with a large inclined occlusal plane angle due to improved dental compensation. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Evaluation of Facial Asymmetry in Patients with Crooked Nose.

BACKGROUND: This study aims to explore the correlation between facial asymmetry and a crooked nose using objective methodologies. METHODS: The cohort of 57 patients who underwent septorhinoplasty surgery for aesthetic reasons between 2019 and 2022. Patients were categorized based on the type of nasal axis deviation. The analysis involved reviewing patients' photographs and cone beam computed tomography images. We identified various anatomical landmarks and compared measurements across the groups. RESULTS: Among the study population, 21 (36.8%) exhibited Type-I (linear) and 15 (26.3%) demonstrated Type-C nasal axis deviation, while no deviation was detected in 21 (36.8%) patients. Upon evaluating the upper face area, significant differences were found in the glabella-lateral orbit (G-LO) and rhinion-lateral orbit (Rh-LO) parameters (p = 0.002 and p < 0.001, respectively). A statistically significant difference was discovered in all three parameters between the three groups in the middle face area [glabella-zygion (G-Zy) p = 0.04, rhinion-zygion (Rh-Zy) P < 0.001, anterior nasal spine-zygion (ANS-Zy) p < 0.001)]. Further, a statistically significant difference was noted in the soft tissue parameters gonion (Go) and LO (p = 0.008 and P = 0.005, respectively). CONCLUSION: Patients with crooked noses, in particular, exhibit asymmetries in the upper and middle faces. The glabella in the upper face and the anterior nasal spine in the middle face are stable points, and the fact that the parameters derived from these two reference points are significant, when considered in conjunction with other significant parameters, strongly supports the aforementioned statement. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Post-BSSO condylar position stability: a comparison of miniplate and lag screw fixation.

BACKGROUND: This study was conceived to assess the postoperative stability of condylar position following fixation with miniplates and lag screws after bilateral sagittal split osteotomy (BSSO). METHODS: This retrospective study included a cohort of 20 patients undergoing BSSO using the Obwegeser-Dal Pont modification. The bony segments were stabilized using either miniplates with two 2.0-mm monocortical screws per segment or three 2.0-mm bicortical lag screws along the mandible's superior border. Pre- and postoperative (7-day interval) spiral computed tomography scans were conducted to assess skeletal changes across both groups. Data analysis employed Wilcoxon signed-rank and Wilcoxon rank-sum tests (α = 0.05). RESULTS: No statistically significant difference was observed between the pre-and postoperative condylar position parameters (P>0.05). However, the lag screw group showed a marginal significant increase in the left condyle's angulation (preoperative: 24.83 ± 6.37 vs. postoperative: 32.5 ± 4.93; P = 0.04). Changes in condylar height, length, and width were not statistically significant before and after BSSO in either groups (P>0.05). Nor was any statistically significant difference found between the miniplates and lag screws groups regarding condylar position parameters (P>0.05). CONCLUSION: The results indicated that both lag screw and miniplate fixation methods can be effectively employed in BSSO procedures without impacting condylar position parameters. Thus, either fixation method can be chosen depending on factors such as the surgeon's preference and clinical outcomes.

Quantitative and qualitative condylar changes following stabilization splint therapy in patients with temporomandibular joint disorders with and without skeletal lateral mandibular asymmetry: a cone beam computed tomographic study.

BACKGROUND: Temporomandibular disorders (TMDs) encompass pain and dysfunction in the jaw, muscles, and adjacent structures. This study aimed to explore the quantitative (condylar position, morphology) and qualitative (bone mineral density (BMD)) therapeutic outcomes following a stabilization splint (S.S.) therapy in adult patients diagnosed with TMD (Arthralgia) with/without lateral mandibular asymmetry (MA) using cone beam computed tomography (CBCT). METHODS: In this retrospective clinical study, 60 adult TMD patients who received S.S. therapy were enrolled and allocated into the TMD group (TMDG) and TMD with MA group (TMD + MAG). The diagnosis was made according to the Diagnostic Criteria for TMD (DC/TMD) AXIS I. MA was measured from the mid-sagittal plane to the Menton point. CBCT was used to scan the temporomandibular joints pre- (T0) and post- (T1)-treatment for three-dimensional analysis. Intra- and intergroup statistical comparisons were performed using the Wilcoxon signed ranks and the Kruskal‒Wallis test. RESULTS: For quantitative comparisons, there was a statistically significant difference between T0 and T1 in the joint spaces of TMD + MAG (anterior, superior, posterior, and coronal lateral on the deviated side as well as in the superior, coronal medial joint space of the contralateral side). Morphologically, the deviated side had a narrower condylar width, reduced condylar height, and a steeper eminence angle. In contrast, the contralateral side tended to have a greater condylar length. For qualitative measurements, BMD also showed statistical significance between T0 and T1 in the majority of the condyle slopes (AS, SS, PS, and LS on the deviated side and in AS and MS on the contralateral side) of TMD + MAG. Additionally, only the AS and PS showed significance in TMDG. CONCLUSION: Multiple joint space widening (AJS and CMS) and narrowing (SJS, PJS, and CLS) could characterize the deviated side in TMD + MA. Factors like narrower condylar width, reduced condylar height, and steeper eminence angle on the deviated side can worsen TMD + MA. Proper alignment of the condyle-disc position is essential for optimal function and load distribution, potentially affecting bone mineral density (BMD). MA plays a prominent role in disturbing bone densities. S.S. therapy shows more evident outcomes in TMD + MAG (on the deviated side compared to the contralateral side) than the TMDG.

Cross-Sectional Study on Self-Perception of Dento-Facial Asymmetry.

Background and Objectives: Facial symmetry is a key component of facial beauty and attractiveness. However, perfect symmetry is rare, and slight asymmetries, also known as natural asymmetries, are common and contribute to the uniqueness of each face. The perception of facial asymmetry varies among individuals and can be influenced by several factors. This study aimed to investigate the self-perception of dento-facial asymmetry among a sample of Romanian individuals, focusing on their awareness, the extent to which it bothers them, and their desire for correction. Materials and Methods: A cross-sectional analytical study was conducted with 283 participants from Romania between January and February 2024. Participants completed a questionnaire designed to assess their self-perception of facial asymmetry and socio-demographic characteristics. The questionnaire included 10 questions on self-perception of facial asymmetry and 8 questions on socio-demographic data. Statistical analysis was performed using SPSS 26.0, and the Pearson Chi-square test was used for comparative analysis. Results: The sample was predominantly female (75.3%) with an average age of 32.24 years. Most participants were from urban areas (80.6%) and had university degrees (58.7%). About 28.7% of participants observed facial asymmetry, with dental asymmetry being the most frequently reported, followed by asymmetries in the eyebrows and eyelids. The right side of the face was more commonly perceived as asymmetric. Although 24.4% of participants were bothered by their asymmetry, 39.2% expressed a desire to correct it. Conclusions: One-third of participants identified dento-facial asymmetry, with the dental level being the most reported. A significant portion of participants expressed a desire to correct their asymmetries, highlighting the importance of understanding self-perception in the context of facial aesthetics. This study underscores the subjective nature of facial asymmetry perception and the varying thresholds for what is considered bothersome or in need of correction.

Facial deformation following treatment for pediatric head and neck rhabdomyosarcoma; the difference between treatment modalities. Results of a trans-Atlantic, multicenter cross-sectional cohort study.

BACKGROUND: The four different local therapy strategies used for head and neck rhabdomyosarcoma (HNRMS) include proton therapy (PT), photon therapy (RT), surgery with radiotherapy (Paris-method), and surgery with brachytherapy (AMORE). Local control and survival is comparable; however, the impact of these different treatments on facial deformation is still poorly understood. This study aims to quantify facial deformation and investigates the differences in facial deformation between treatment modalities. METHODS: Across four European and North American institutions, HNRMS survivors treated between 1990 and 2017, more than 2 years post treatment, had a 3D photograph taken. Using dense surface modeling, we computed facial signatures for each survivor to show facial deformation relative to 35 age-sex-ethnicity-matched controls. Additionally, we computed individual facial asymmetry. FINDINGS: A total of 173 HNRMS survivors were included, survivors showed significantly reduced facial growth (p < .001) compared to healthy controls. Partitioned by tumor site, there was reduced facial growth in survivors with nonparameningeal primaries (p = .002), and parameningeal primaries (p ≤.001), but not for orbital primaries (p = .080) All patients were significantly more asymmetric than healthy controls, independent of treatment modality (p ≤ .001). There was significantly more facial deformation in orbital patients when comparing RT to AMORE (p = .046). In survivors with a parameningeal tumor, there was significantly less facial deformation in PT when compared to RT (p = .009) and Paris-method (p = .007). INTERPRETATION: When selecting optimal treatment, musculoskeletal facial outcomes are an expected difference between treatment options. These anticipated differences are currently based on clinicians' bias, expertise, and experience. These data supplement clinician judgment with an objective analysis highlighting the impact of patient age and tumor site between existing treatment options.

Facial asymmetry in children with either unilateral lambdoid craniosynostosis or positional posterior plagiocephaly.

BACKGROUND: In unilateral lambdoid craniosynostosis (ULC), the posteriorly situated lambdoid suture of the cranial vault fuses prematurely. Positional posterior plagiocephaly (PPP) causes flattening of the posterior side of the head, either through external forces or through underlying differences in brain development. Both conditions cause occipital flattening of the head, but the aetiology is different. MATERIALS AND METHODS: Eight ULC children were compared with 16 sex- and age-matched PPP children. 3D computer tomography scans of all 24 children were analysed with Dolphin imaging software. The location and symmetry of the temporomandibular joint (Co), and the symmetry of the maxillary anterior nasal spine (ANS) and the mandibular symphysis (Pgn) were analysed. Furthermore, the mandibular bone (Co-Pgn) length, corpus length, ramus height, positional changes in the external acoustic meatus (PoL) and the distance from the orbital margin to the articular fossa were measured. RESULTS: In all eight ULC children, the Co was anteriorly displaced on the affected side compared with the unaffected side. In all ULC and PPP children, the ANS, which is considered the bony maxillary midpoint, was shifted towards the affected side. In all ULC children, the mandibular bone (Co-Pgn) was shorter on the affected side. The PoL was antero-inferiorly positioned in all ULC children on the affected side compared with the unaffected side. CONCLUSIONS: Our results show that both types of posterior plagiocephaly are associated with an asymmetric position of the Co and asymmetry of the mandible and maxilla. Facial asymmetry was more frequently seen in ULC than PPP children.

'Study of the maxillary yaw on cone beam computed tomography: A preliminary report and comparison between two different dento-skeletal malocclusions'.

OBJECTIVES: To assess the skeletal and dental maxillary transverse compensation (yaw) on the cone beam computed tomography (CBCT) three-dimensional reconstructed image of the skull in two groups of patients, both clinically affected by a class III malocclusion with deviation of the lower midline. MATERIALS AND METHODS: An observational retrospective study was designed to analyse differences in two groups of patients, the first one was composed by patients affected by horizontal condylar hyperplasia, the second one by patients affected by dento-skeletal asymmetric class III malocclusion. Each group was composed by 15 patients. Transverse analysis was performed by measuring five landmarks (three bilateral and two uneven) with respect to a mid-sagittal plane; sagittal analysis was performed by measuring the sagittal distance on the mid-sagittal plane between bilateral points. Means were compared through inferential analysis. RESULTS: In the condylar hyperplasia group, all differences between the two sides were not statistically significant, nor for canines' difference (P = .0817), for molars (P = .1105) or for jugular points (.05871). In the class III group, the differences between the two sides were statistically significant for molars (P = .0019) and jugular points (P = .0031) but not for canines (P = .1158). Comparing the two groups, significant differences were found only for incisors' midline deviation (P = .0343) and canine (P = .0177). CONCLUSION: The study of the yaw on CBCT should be integrated into three-dimensional cephalometry and could help in differentiating the various malocclusion patterns.

Three-dimensional assessment of facial asymmetry in class III subjects, part 2: evaluating asymmetry index and asymmetry scores.

OBJECTIVES: To evaluate the outcomes of corrective surgical treatment for craniofacial asymmetry using four different methods with the aim of developing the best technique for craniofacial asymmetry assessment. MATERIALS AND METHODS: CBCT images of twenty-one class III subjects with surgically corrected craniofacial asymmetry and twenty-one matched controls were analyzed. Twenty-seven hard tissue landmarks were used to quantify asymmetry using the following methodologies: the asymmetry index (AI), asymmetry scores based on the clinically derived midline (CM), Procrustes analysis (PA), and modified Procrustes analysis (MPA). RESULTS: Modified Procrustes analysis successfully identified pre-operative asymmetry and revealed severe asymmetry at the mandibular regions compared to controls, which was comparable to the asymmetry index and clinically derived midline methods, while Procrustes analysis masked the asymmetric characteristics. Likewise, when comparing the post-surgical outcomes, modified Procrustes analysis not only efficiently determined the changes evidencing decrease in facial asymmetry but also revealed significant residual asymmetry in the mandible, which was congruent with the asymmetry index and clinically derived midline methods but contradictory to the results shown by Procrustes analysis. CONCLUSIONS: In terms of quantifying cranio-facial asymmetry, modified Procrustes analysis has evidenced to produce promising results that were comparable to the asymmetry index and the clinically derived midline, making it a more viable option for craniofacial asymmetry assessment. CLINICAL RELEVANCE: Modified Procrustes analysis is proficient in evaluating cranio-facial asymmetry with more valid clinical representation and has potential applications in assessing asymmetry in a wide spectrum of patients, including syndromic patients.

Quantified analysis of facial movement: A reference for clinical applications.

Most techniques for evaluating unilateral impairments in facial movement yield subjective measurements. The objective of the present study was to define a reference dataset and develop a visualization tool for clinical assessments. In this prospective study, a motion capture system was used to quantify facial movements in 30 healthy adults and 2 patients. We analyzed the displacements of 105 reflective markers placed on the participant's face during five movements (M1-M5). For each marker, the primary endpoint was the maximum amplitude of displacement from the static position (M0) in an analysis of variance. The measurement precision was 0.1 mm. Significant displacements of markers were identified for M1-M5, and displacement patterns were defined. The patients and age-matched healthy participants were compared with regard to the amplitude of displacement. We created a new type of radar plot to visually represent the diagnosis and facilitate effective communication between medical professionals. In proof-of-concept experiments, we collected quantitative data on patients with facial palsy and created a patient-specific radar plot. Our new protocol for clinical facial motion capture ("quantified analysis of facial movement," QAFM) was accurate and should thus facilitate the long-term clinical follow-up of patients with facial palsy. To take account of the limitations affecting the comparison with the healthy side, we created a dataset of healthy facial movements; our method might therefore be applicable to other conditions in which movements on one or both sides of the face are impaired. The patient-specific radar plot enables clinicians to read and understand the results rapidly.

Mandibular condylar hyperplasia and its correlation with vascular endothelial growth factor.

BACKGROUND: Condylar hyperplasia (CH) is a rare condition characterised by excessive unilateral growth of the mandibular condyle after cessation of growth on the contralateral side causing facial asymmetry, being more prevalent in the second and third decades. OBJECTIVE: The aim of this study was to determine the utility of vascular endothelial growth factor (VEGF-A) as a diagnostic and prognostic factor in condylar hyperplasia, and to determine its potential viability as a therapeutic target. METHODS: This is a case-control study, where 17 mandibular condyles specimens were collected from 17 patients treated for active mandibular condyle hyperplasia and three unaffected human mandibular condyles from cadavers will serve as the control group. The samples were immunostained with VEGF-A antibody and evaluated on both quantity and intensity of staining. RESULTS: VEGF-A was qualitatively found to be greatly upregulated in patients with condylar hyperplasia. CONCLUSION: VEGF-A was qualitatively found to be upregulated in patients affected by CH, validating VEGF-A as a potential diagnostic, prognostic and therapeutic target.

Correlation of social smile symmetry with facial symmetry.

BACKGROUND: This study aimed to assess the correlation of social smile symmetry with facial symmetry. METHODS: In this cross-sectional study, frontal view photographs were obtained from 169 eligible patients at rest and smiling with a camera at the level of their nose tip. Several landmarks were selected for facial symmetry and measured at rest and social smiling at the two sides of the face. The respective formula was used to calculate the asymmetry index (AI). The mean values for each AI were calculated, and the correlation between the criteria for a symmetric smile in a social smile with the criteria for facial symmetry, and the correlation between the difference in symmetry criteria at rest and social smiling with facial symmetry criteria were analyzed. RESULTS: Significant correlations were noted between Oc-b AI (smile) and Sn-B (rest) facial AI (P = 0.046), An-a (smile) AI and Gn-a (rest) facial AI (P = 0.002), An-b (smile) AI and Sn-b (rest) facial AI (P < 0.001), Pog-a (smile) and Sn-a (rest) facial AI (P < 0.001), Nt-a (smile) and Sn-a (rest) facial AI (P < 0.001), Nt-b (smile) and Sn-b (rest) facial AI (P < 0.001), Ph-a (smile) and Sn-a (rest) facial AI (P < 0.001), Ph-b (smile) and Sn-b (smile) facial AI (P = 0.007), Oc-b AI (difference) and Gn-b (rest) facial AI (P = 0.031), Oc-Pog (difference) AI and Gn-b (rest) facial AI (P = 0.041), An-b (difference) AI and Sn-b (rest) facial AI (P < 0.001), Nt-a (difference) and Sn-a (rest) facial AI (P = 0.006), Nt-b (difference) and Sn-b (rest) facial AI (P < 0.001), and Ph-b (difference) and Sn-b (rest) facial AI (P < 0.001). CONCLUSIONS: A significant correlation exists between social smile symmetry and facial symmetry.