3D evaluation model of facial aesthetics based on multi-input 3D convolution neural networks for orthognathic surgery.

BACKGROUND: Quantitative evaluation of facial aesthetics is an important but also time-consuming procedure in orthognathic surgery, while existing 2D beauty-scoring models are mainly used for entertainment with less clinical impact. METHODS: A deep-learning-based 3D evaluation model DeepBeauty3D was designed and trained using 133 patients' CT images. The customised image preprocessing module extracted the skeleton, soft tissue, and personal physical information from raw DICOM data, and the predicting network module employed 3-input-2-output convolution neural networks (CNN) to receive the aforementioned data and output aesthetic scores automatically. RESULTS: Experiment results showed that this model predicted the skeleton and soft tissue score with 0.231 ± 0.218 (4.62%) and 0.100 ± 0.344 (2.00%) accuracy in 11.203 ± 2.824 s from raw CT images. CONCLUSION: This study provided an end-to-end solution using real clinical data based on 3D CNN to quantitatively evaluate facial aesthetics by considering three anatomical factors simultaneously, showing promising potential in reducing workload and bridging the surgeon-patient aesthetics perspective gap.

Male Rejuvenation: Injectables.

The use of injectables can effectively treat the areas of greatest facial esthetic concern in males. Due to significant differences in the facial anatomy of men compared to women, treatment strategy, dosage, and technique differs. This article will review the pharmacology, preparation, pertinent anatomy, technique, risks, and adverse events associated with injectable agents emphasizing unique differences in male anatomy and esthetics.

Determination of Mouth Width for Facial Reconstruction Based on Statistical Regression Model.

INTRODUCTION: It is important to generate predictable statistical models by increasing the number of variables on the human skeletal and soft tissue structures on the face to increase the accuracy of human facial reconstructions. The purpose of this study was to determine mouth width 3-dimensionally based on statistical regression model. MATERIAL AND METHODS: Cone-beam computed tomography scan data from 130 individuals were used to measure the horizontal and vertical dimensions of orbital and nasal structures and intercanine width. The correlation between these hard tissue variables and the mouth width was evaluated using the statistical regression model. RESULTS: Orbital width, nasal width, and intercanine width were found to be strong predictors of the mouth width determination and were used to generate the regression formulae to find the most approximate position of the mouth. CONCLUSION: These specific variables may contribute to improving the accuracy of mouth width determination for oral and maxillofacial reconstructions.

Photographic Parameters in Three-Dimensional Facial Image Acquisition. A Scoping Review.

OBJECTIVE: Orthognathic surgery is a viable and reproducible treatment for facial deformities. Despite the precision of the skeletal planning of surgical procedures, there is little information about the relations between hard and soft tissues in three-dimensional (3D) analysis, resulting in unpredictable soft tissue outcomes. Three-dimensional photography is a viable tool for soft tissue analysis because it is easy to use, has wide availability, low cost, and is harmless. This review aims to establish parameters for acquiring consistent and reproducible 3D facial images. METHODS: A scoping review was conducted across PubMed, SCOPUS, Scientific Electronic Library Online (SciELO), and Web of Science databases, adhering to "Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews" guidelines. Articles presenting 3D facial photographs in the diagnostic phase were considered. RESULTS: A total of 79 articles were identified, of which 29 were selected for analysis. CONCLUSION: The predominant use of automated systems like 3dMD and VECTRA M3 was noted. User positioning has highest agreement among authors. Noteworthy aspects include the importance of proper lighting, facial expression, and dental positioning, with observed discrepancies and inconsistencies among authors. Finally, the authors proposed a 3D image acquisition protocol based on this research findings.

Ethnic variation in lower face anthropometry on facial computed tomography scans for patients seeking facial feminization surgery.

BACKGROUND: Facial feminization surgery (FFS) is the most common form of facial gender-affirming surgery. One of the current knowledge gaps is the understanding of differences among racial groups in baseline craniofacial norms for transgender and nonbinary patients. METHODS: All patients who sought consultation for FFS and underwent craniofacial computed tomography (CT) scans at a single institution between 2018 and 2023 were included. Patients who underwent previous facial surgeries were excluded. Chart reviews were conducted for patient characteristics, including race, age, hormone therapy duration, and prior gender-affirming surgeries. Racial categorizations included White, Latinx, African American, or Asian. Patients with other or multiracial identities were excluded. Lower face measurements were derived from preoperative facial CT scans. Comparative analyses were performed on all measurements among the racial groups. RESULTS: In this study, 204 patients were included with an average age of 32.0 ± 10.2 years and a median hormone therapy duration of 2.0 years. The notable differences among the racial groups were: 1. Zygomatic width was the largest in Asian patients (13.5 ± 0.6 cm) compared to all other racial groups (p = 0.03), 2. Nasolabial angle was the smallest in African American patients (82.5 ± 13.1 degrees, p < 0.001), 3. Lower face height was the largest in African American patients (6.9 ± 0.7 cm, p < 0.001), and 4. Lateral mandibular flare was the largest in African American patients (0.4 ± 0.1 cm) and the smallest in Latinx patients (0.2 ± 0.1 cm, p < 0.001). CONCLUSIONS: Specific target areas of FFS should be carefully considered to account for possible baseline ethnic differences. Relative facial proportions may also be a more salient surgical planning tool in transgender and gender nonbinary patients rather than absolute measurements alone.

Evaluation of Facial Aging in Different Age and Gender Groups With Computed Tomography-Based Calvarium and Face Measurements.

BACKGROUND: The human face is a complex area formed by the combination of many different components and varies among individuals according to gender, age, and ethnicity. OBJECTIVE: The aim of this study was to evaluate age-related changes in the facial and calvarial bones in a large sample of both genders. METHODS: The retrospective study included nontraumatic brain computed tomography scans of 280 Turkish adults. Participants were divided into 7-decade groups with the age ranging from 20 to 89 years. Measurements of the face and calvaria were recorded, and calvarial volume was calculated. The relationship of these parameters with age and gender was examined. RESULTS: Statistically significant differences were observed in all the facial and calvarial measurements, except the transverse diameter of the head, with increasing age in both genders. Regardless of age, no significant differences were found in facial and calvarial measurements between genders. In addition, there was a significant decrease in the calvarial volume in both genders after the seventh decade of life. CONCLUSION: The structure of the face and calvarium continues to change and differentiate throughout life. Taking these changes into account during surgical and facial rejuvenation procedures can help predict outcomes and avoid the use of incorrect techniques.

3D extraoral morphometric changes after implant surgery: an exploratory pilot study using stereophotogrammetry.

OBJECTIVE: This pilot study aimed to evaluate, for the first time, the changes in facial tissues following the placement of a single dental implant. METHOD AND MATERIALS: Patients were scanned with a 3D facial scanner (3dMD) before implant surgery, immediately after surgery (T1), at 7 days postoperatively (T2), and at the impression stage (T3). Acquired images were processed using the 3dMDvultus (3dMD) software program and volume differences and linear depth measurements were calculated to determine the morphometric changes over time. A total of 11 patients were included in the analyses. Descriptive statistics were employed to analyze the data. RESULTS: The volumetric changes and maximum depth differences indicated an initial increase, followed by a progressive decrease in tissue volume after implant placement in the area of the surgery. The volume change values ranged between 2.5 and 3.9 cm3 for T1, whereas for T2, the volume change decreased to a range of 0.8 to 1.8 cm3. Maximum depth differences ranged between 2.06 and 2.80 mm in the soft tissues immediately after the implant surgery and reduced to around 2.01 to 0.55 mm at the impression stage. The amount of painkiller used was not related to the magnitude of linear depth measurements at any assessed time point. CONCLUSION: There was a longitudinal decrease in soft tissue volume and depth difference in extraoral soft tissues in the region of implant placement after surgery up to 6 weeks. The use of a facial scanner is a promising noninvasive method to monitor 3D morphometric changes after implant surgery.

Frontal facial analysis of female celebrity attractiveness standards through artificial intelligence.

The contemporary significance of celebrities' facial aesthetics underscores their heightened importance in shaping attractiveness standards. This retrospective study aimed to investigate the impact of patterns on aesthetic canons in the profile views of female celebrities, using artificial intelligence. The study sought to compare different races and propose standards for attractive faces. In this retrospective cohort study, a Python-based algorithm was used to analyze frontal patterns and evaluate their influence on aesthetic norms in publicly accessible images of female global celebrities. Ten ideal angular or proportional measures were gathered from the literature, and were trained to serve as a benchmark for the analysis of facial attractiveness. Demographic characteristics were described statistically. A one-way ANOVA test was employed to assess data distribution. Differences in means between groups were evaluated using nonparametric independent-sample tests, with statistical significance set at < 0.05. The study involved facial analyses for 115 female celebrities. It revealed variations in facial features among races. The mean golden ratio differed, with African and Asian individuals showing lower ratios. Symmetry varied, with Latin and Caucasian faces considered the most symmetrical. The zygomatic-to-mandibular width ratio was similar across races, with a ratio close to 80% being associated with more attractive faces. Differences in nose-to-mouth ratio, lips, alar base width, and chin angle were noted among race groups. The study concluded that, regardless of race, an attractive female face is characterized by specific ratios and angles. Facial symmetry, though desirable, is not strictly necessary. Irrespective of race background, an appealing female face is characterized by a zygomatic-to-mandibular width ratio nearing 80%, a mid-facial third that is slightly larger than the lower third, and a distinctive chin angle of approximately 138°, contributing to a trapezoidal facial shape. The findings contribute valuable insights into attractiveness standards and the impact of frontal patterns on aesthetic canons in female celebrities.

The "Central Tendency Bias" in the assessment of facial attractiveness in group-based and individual ratings-A survey-based study in 727 volunteers.

BACKGROUND: The increasing number of esthetic procedures emphasizes the need for effective evaluation methods of outcomes. Current practices include the individual practitioners' judgment in conjunction with standardized scales, often relying on the comparison of before and after photographs. This study investigates whether comparative evaluations influence the perception of beauty and aims to enhance the accuracy of esthetic assessments in clinical and research settings. OBJECTIVE: To compare the evaluation of attractiveness and gender characteristics of faces in group-based versus individual ratings. METHODS: A sample of 727 volunteers (average age of 29.5 years) assessed 40 facial photographs (20 male, 20 female) for attractiveness, masculinity, and femininity using a 5-point Likert scale. Each face was digitally edited to display varying ratios in four lip-related proportions: vertical lip position, lip width, upper lip esthetics, and lower lip esthetics. Participants rated these images both in an image series (group-based) and individually. RESULTS: Differences in the perception of the most attractive/masculine/feminine ratios for each lip proportion were found in both the group-based and individual ratings. Group ratings exhibited a significant central tendency bias, with a preference for more average outcomes compared with individual ratings, with an average difference of 0.50 versus 1.00. (p = 0.033) CONCLUSION: A central tendency bias was noted in evaluations of attractiveness, masculinity, and femininity in group-based image presentation, indicating a bias toward more "average" features. Conversely, individual assessments displayed a preference for more pronounced, "non-average" appearances, thereby possibly pointing toward a malleable "intrinsic esthetic blueprint" shaped by comparative context.

El reposicionamiento malar. Presentación de una técnica original: punto MM / Malar repositioning. Presentation of an original technique: point MM

El envejecimiento facial es una sinergia compleja de cambios texturales de la piel, hiper- o hipoactividad muscular, reabsorción del tejido graso y resorción ósea. El déficit de volumen resultante, la deflación y la posterior caída del tercio medio facial produce una cara menos atractiva y juvenil. Los procedimientos inyectables en región malar son cada vez más populares y solicitados por los pacientes. El conocimiento de la anatomía de la cara media es fundamental para el inyector. La comprensión de la irrigación facial puede ayudar a disminuir la exposición a la aparición de hematomas y complicaciones vasculares severas. Existen múltiples técnicas de inyección propuestas para el tercio medio, en este artículo presentamos una técnica original, simple, segura y eficaz con resultados satisfactorios y riesgo reducido

Facial aging is a complex synergy of textural skin changes, muscle hyperactivity, fat dysmorphism, bone resorption. The resulting volume deficit and deflation of the mid face produces a less attractive and youthful face. Injectable midface procedures are becoming increasingly popular and requested by patients. Knowledge of the anatomy of the midface is critical for the injector. Understanding the irrigation of the face can help decrease the risk of hematoma and severe vascular complications. There are multiple injection techniques proposed for the middle third, in this article we present a simple, safe and effective technique with satisfactory results and lower risk

Correlation analysis of airway-facial phenotype in Crouzon syndrome by geometric morphometrics: A promising method for non-radiation airway evaluation.

AIM: This study aimed to verify the correlation of the airway-facial phenotype and visualize the morphological variation in Crouzon syndrome patients. Additionally, to develop a non-radiation methodology for airway assessments. METHOD: In this study, 22 patients diagnosed with Crouzon syndrome (Age: 7.80 ± 5.63 years; Gender distribution: 11 females and 11 males) were analysed. The soft tissue surface and airway were three-dimensionally reconstructed, and the entire facial phenotype was topologized and converted into spatial coordinates. Geometric morphometrics was employed to verify the correlation and visualize dynamic phenotypic variation associated with airway volume. A total of 276 linear variables were automatically derived from 24 anatomical landmarks, and principal component analysis (PCA) identified the 20 most significant parameters for airway evaluation. Correlation analyses between parameters and airway volume were performed. Then, patients were classified into three groups based on airway volume, and the differences among the groups were compared for evaluating the differentiating effectiveness of parameters. RESULTS: The facial phenotype was strongly correlated with the airway (coefficient: 0.758). Morphological variation was characterized by (i) mandibular protrusion and anticlockwise rotation; (ii) midface retrusion; (iii) supraorbital frontward and (iv) lengthening of the facial height. All the anthropometric parameters were strongly associated with the airway, and the differences among the groups were statistically significant. CONCLUSION: This study confirmed the strong correlation between facial phenotype and airway parameters in Crouzon syndrome patients. Despite the development of the airway, pathological midface retrusion was still aggravated, suggesting that surgical intervention was inevitable. Three-dimensional facial anthropometry has potential as a non-radiation examination for airway evaluation.

Three-dimensional analysis of hard and soft tissue changes in skeletal class II patients with high mandibular plane angle undergoing surgery.

This study aimed to study 3-dimensional (3D) changes of hard and soft tissues of skeletal class II patients after 2-jaw surgery and genioplasty. 32 adult patients diagnosed with mandibular hypoplasia who underwent 2-jaw surgery of maxillary impaction, mandibular advancement and genioplasty were enrolled. Cone-beam computed tomography and 3D stereophotogrammetry was conducted 1 week before and 6 months after surgery. Dolphin imaging software was used to establish a 3D digitizing model and 3D measurement system. Paired t-test was performed to compare the values before and after surgery. Pearson's correlation test assessed the degree of correlations between hard and soft tissue change. The mean impaction of the maxilla was 2.600 ± 3.088 mm at A. The mean advancement of the mandible was 7.806 ± 2.647 mm at B. There was a significant upward and forward movement for most landmarks of the nose and lip, while a significant decrease in nasal tip height (lateral view), upper lip height, and upper and lower vermilion height. The nose's width was significantly increased. For maxillary, Sn, Ac-r, Ac-l, and Ls demonstrated a significant correlation with A and U1 in the anteroposterior axis. However, there were no significant correlations among them in the vertical axis. For mandibular, Li demonstrated a significant correlation with L1 in the anteroposterior axis specifically for the mandible. Notably, correlations between the landmarks of the chin's hard and soft tissues were observed across all axes. The utilization of 3-D analysis facilitated a quantitative comprehension of both hard and soft tissues, thereby furnishing valuable insights for the strategic formulation of orthognathic treatment plans targeting patients with skeletal class II conditions.

Defining Ideal Pretarsal Rolls Through a Morphometric Analysis in Asians.

BACKGROUND: Pretarsal rolls are a crucial aesthetic feature. Despite numerous studies conducted on periorbital aesthetics, there remains a dearth of research on the ideal pretarsal rolls. OBJECTIVES: This study aimed to investigate 4 aesthetic characteristics of ideal pretarsal rolls: presence, width, proportion, and morphology. METHODS: Respondents (385, including 80 aesthetic specialists) were presented with 7 series of images of pretarsal rolls, including 2 series of pretarsal roll existence, 2 series of varying widths, 2 series of different ratios between pretarsal roll and palpebral fissure height, and 1 series about morphology. Participants were asked to rank each image within a given series from most attractive to least attractive. The rankings were then analyzed according to population demographics. RESULTS: The majority of respondents deemed images with pretarsal rolls to be more aesthetically pleasing (P < .001) than those without such features. Additionally, pretarsal rolls with a width of 5 mm (P < .001), a ratio to palpebral fissure height of 0.5:1 (P < .001), and a crescent shape (P < .001) were perceived as the most attractive. Moreover, individuals aged 40 or younger exhibited a significant preference for images with pretarsal rolls compared to older groups (P < .001), and females displayed a greater inclination toward a medium ratio of pretarsal roll to palpebral fissure height than males did (0.5:1 P = .003, 0.618:1 P < .001). CONCLUSIONS: This study validates the optimal characteristics of pretarsal rolls, which provides insight into pretarsal roll aesthetics and holds significant implications for surgical planning and effect assessment in future periocular procedures involving pretarsal rolls.

Associations between the 3D position of the mental foramen with sagittal skeletal relationships (classes I, II, and III) and vertical facial growth patterns (normal, long, and short faces) in different ages and sexes: a retrospective cohort study of 360 CBCTs.

BACKGROUND: The 3D position of the mental foramen (MF) is of significant clinical value in dental implantology and mandibular surgeries or in local anesthesia. Despite its importance, it is not clearly known how the position of MF can alter in different individuals, since the literature on the associations between the MF position with vertical growth patterns is non-existent and those on links between the MF position and skeletal malocclusions are scarce. Therefore, we aimed to investigate these, for the first time, on cone-beam computed tomographies (CBCTs). METHODS: Archival CBCTs of 9 sub-groups (i.e., 3 skeletal Classes I, II, and III × 3 vertical growth patterns 'long face, short face, normal face') were collected by evaluating patients' SNA, SNB, ANB, facial angle, lower facial height, and FMA (n = 9 × 40 = 360). Included cases were older than 17 years and without any history of orthodontic/orthognathic treatments (243 women, 117 men, mean age: 22.28 ± 2.80 years). Perpendicular distances between the MF and 3 fixed bony structures (the mandibular symphysis [S/width], the mandibular ramus [R/length], and the mandibular lower cortex [C/height]) were measured on different sectional planes on both hemimandibles. Left- and right-side measurements were combined. Data were analyzed using the 3-way ANCOVA, Bonferroni, one-way ANOVA, Tamhane, Pearson, and t-test (α = 0.05). RESULTS: Width was the smallest in Class II and greatest in Class III cases (all P values < 0.000001, Bonferroni). It was the shortest in long faces and longest in short faces (all P values ≤ 0.00008). The inferior-superior height was larger in Class III than both Classes I and II (both P values ≤ 0.003); there was no significant difference between Classes I and II in terms of height (P = 0.684). Height was the largest in long faces and smallest in short faces (all P values < 0.000001). The anterior-posterior length was the largest in Class III and smallest in Class II (all P values < 0.000001). Length was larger in short-face people versus normal- or long-face individuals (P ≤ 0.00003); nevertheless, long and normal faces did not differ in terms of length (P = 0.448). Subjects' age was not correlated with their MF positions (P ≥ 0.579, Pearson coefficient). Sex dimorphism existed only for height (P = 0.009, t-test) but not for length or width. CONCLUSIONS: The MF position may considerably differ in various horizontal or vertical growth patterns and sexes. This should be noted in mandible surgeries.

Anatomical Characteristics, Relations, and Clinical Considerations of the Facial Index and Cephalic Index in Young Chileans Aged Between 18 and 21 Years / Características Anatómicas, Relaciones y Consideraciones Clínicas del Índice Facial e Índice Cefálico en Jóvenes Chilenos entre 18 y 21 Años

SUMMARY: Humans throughout history have shown similarities between both their cephalic and facial complexion, among certain ethnic groups, due to genetic and demographic factors. Several studies have demonstrated the different constitutions of specific groups of people in order to generate data of a certain population or group. The present research aims to preliminarily study the existence of possible relations between Cephalic Index and Facial Index among categories of individuals in an odontology student population from a private university in Santiago, Chile. Empirical, descriptive, and cross-sectional study. In this study, 129 students with age range 18-21 were taken as subjects in a non-probabilistic way. Regarding Cephalic Index (CI), the Retzius classification was used, and the Facial Index (FI) was measured considering the maximum height of the face, from nasion to gnathion (Na-Gn), and the maximum width, from right zygion to left zygion (Zr-Zl). In this study, 129 people were taken as sample, 82 females and 47 males. Among women, the most predominant cephalic biotype was brachycephalic (59.8 %), followed by mesocephalic (37.8 %), and dolichocephalic (2.4 %). On the other hand, men's most common biotype was mesocephalic (57.5 %), followed by brachycephalic (36.2 %), and dolichocephalic (6.4 %). Regarding facial biotype, both in female and male subjects the following pattern was shown: euryprosopic (F: 59.7 %, M: 59.6 %), mesoprosopic (F: 26.8 %, M: 29.8 %), and leptoprosopic (F: 13.4 %, M: 10.6 %). Facial parameters of the subjects (odontology students from a Chilean university) tend to be mostly euryprosopic, followed by mesoprosopic and leptoprosopic. Additionally, mesocephalic biotypes tend to be similar to other studies conducted in Chile.

Los seres humanos a lo largo de la historia han mostrado similitudes tanto entre su complexión cefálica como facial, entre ciertos grupos étnicos, debido a factores genéticos y demográficos. Varios estudios han demostrado las diferentes constituciones de grupos específicos de personas para poder generar datos de una determinada población o grupo. La presente investigación tiene como objetivo estudiar preliminarmente la existencia de posibles relaciones entre el Índice Cefálico y el Índice Facial entre categorías de individuos en una población de estudiantes de odontología de una universidad privada de Santiago, Chile, en un estudio empírico, descriptivo y transversal. En este estudio, se tomó como sujetos de forma no probabilística a 129 estudiantes con edades comprendidas entre 18 y 21 años. Respecto al Índice Cefálico (IC), se utilizó la clasificación de Retzius, y el Índice Facial (FI) se midió considerando la altura máxima de la cara, desde nasión hasta gnatión (Na-Gn), y el ancho máximo, desde cigio derecho a izquierdo. cigio (Zr-Zl). En este estudio se tomó como muestra 129 personas, 82 mujeres y 47 hombres. Entre las mujeres, el biotipo cefálico más predominante fue el braquicéfalo (59,8 %), seguido del mesocefálico (37,8 %) y el dolicocéfalo (2,4 %). Por otro lado, el biotipo más común en los hombres fue el mesocefálico (57,5 %), seguido del braquicéfalo (36,2 %) y el dolicocéfalo (6,4 %). Respecto al biotipo facial, tanto en sujetos femeninos como masculinos se mostró el siguiente patrón: euriprosópico (F: 59,7 %, M: 59,6 %), mesoprosópico (F: 26,8 %, M: 29,8 %) y leptoprosópico (F: 13,4 %, M: 10,6 %). Los parámetros faciales de los sujetos (estudiantes de odontología de una universidad chilena) tienden a ser en su mayoría euriprosópicos, seguidos de mesoprosópicos y leptoprosópicos. Además, los biotipos mesocefálicos tienden a ser similares a otros estudios realizados en Chile.

Can smartphones be used for routine dental clinical application? A validation study for using smartphone-generated 3D facial images.

OBJECTIVES: To compare the accuracy of smartphone-generated three-dimensional (3D) facial images to that of direct anthropometry (DA) and 3dMD with the aim of assessing the validity and reliability of smartphone-generated 3D facial images for routine clinical applications. MATERIALS AND METHODS: Twenty-five anthropometric soft-tissue facial landmarks were labelled manually on 22 orthognathic surgery patients (11 males and 11 females; mean age 26.2 ± 5.3 years). For each labelled face, two imaging operations were performed using two different surface imaging systems: 3dMDface and Bellus3D FaceApp. Next, 42 inter-landmark facial measurements amongst the identified facial landmarks were measured directly on each labelled face and also digitally on 3D facial images. The measurements obtained from smartphone-generated 3D facial images (SGI) were statistically compared with those from DA and 3dMD. RESULTS: SGI had slightly higher measurement values than DA and 3dMD, but there was no statistically significant difference between the mean values of inter-landmark measures across the three methods. Clinically acceptable differences (≤3 mm or ≤5°) were observed for 67 % and 74 % of measurements with good agreement between DA and SGI, and 3dMD and SGI, respectively. An overall small systematic bias of ± 0.2 mm was observed between the three methods. Furthermore, the mean absolute difference between DA and SGI methods was highest for linear (1.41 ± 0.33 mm) as well as angular measurements (3.07 ± 0.73°). CONCLUSIONS: SGI demonstrated fair trueness compared to DA and 3dMD. The central region and flat areas of the face in SGI are more accurate. Despite this, SGI have limited clinical application, and the panfacial accuracy of the SGI would be more desirable from a clinical application standpoint. CLINICAL SIGNIFICANCE: The usage of SGI in clinical practice for region-specific macro-proportional facial assessment involving central and flat regions of the face or for patient education purposes, which does not require accuracy within 3 mm and 5° can be considered.

Soft tissue prediction in orthognathic surgery: Improving accuracy by means of anatomical details.

Three-dimensional virtual simulation of orthognathic surgery is now a well-established method in maxillo-facial surgery. The commercial software packages are still burdened by a consistent imprecision on soft tissue predictions. In this study, the authors produced an anatomically detailed patient specific numerical model for simulation of soft tissue changes in orthognathic surgery. Eight patients were prospectively enrolled. Each patient underwent CBCT and planar x-rays prior to surgery and in addition received an MRI scan. Postoperative soft-tissue change was simulated using Finite Element Modeling (FEM) relying on a patient-specific 3D models generated combining data from preoperative CBCT (hard tissue) scans and MRI scans (muscles and skin). An initial simulation was performed assuming that all the muscles and the other soft tissue had the same material properties (Homogeneous Model). This model was compared with the postoperative CBCT 3D simulation for validation purpose. Design of experiments (DoE) was used to assess the effect of the presence of the muscles considered and of their variation in stiffness. The effect of single muscles was evaluated in specific areas of the midface. The quantitative distance error between the homogeneous model and actual patient surfaces for the midface area was 0.55 mm, standard deviation 2.9 mm. In our experience, including muscles in the numerical simulation of orthognathic surgery, brought an improvement in the quality of the simulation obtained.

Comparative Evaluation of Cranial Base Length and Flexure on Facial Parameters in Hypodivergent, Normodivergent and Hyperdivergent Patients: A Retrospective Cephalometric Study.

AIM: The aim of the study was to assess the influence of cranial base length (CBL) and Flexure on facial parameters in Hypodivergent, Normodivergent, and Hyperdivergent patients. MATERIALS AND METHODS: Around 60 standardized cephalograms were divided into Hypodivergent, Normodivergent, and Hyperdivergent groups (20 each) based on the FMA angle. The CBL, cranial flexure (CF), and various facial parameters were measured for each case. The results were analyzed for the correlation between Cranial and facial parameters in each of the three study groups. RESULTS: Comparison and Pairwise Comparison of variables between study groups were done using ANOVA and Tukey's post hoc Test. Cranial base length, mandibular body length, LAFH, N-Me-Go angle (p-value <0.001), and Jarabak's ratio were found to be significantly different between the groups. Pearson's Correlation showed that most of the facial parameters had a significant correlation with CBL in Hypodivergent groups. CONCLUSION: The CBL is more closely related to facial parameters in vertical dysplasia individuals than CF. The CBL is positively correlated to facial variables, especially in Hypodivergent individuals. The N-Me-Go Angle introduced in the study was significantly different in all three vertical facial types studied; hence, it cannot be used as a valuable diagnostic tool. CLINICAL SIGNIFICANCE: Changes in the length and flexure of the cranial base influence the anteroposterior position of jaw bases. The influence of the cranial base on the development of vertical dysplasias is not studied much, hence the present study aims at resolving this lacuna in literature.

[Injection anatomy-a new discipline in aesthetic medicine]. / Injektionsanatomie ­ eine neue Disziplin der ästhetischen Medizin.

The basic anatomical understanding of aesthetic medicine has changed fundamentally since the turn of the millennium. With the advent of modern minimally invasive injection procedures using botulinum toxin and hyaluronic acid fillers, anatomical structures that had previously received little attention and were not considered relevant have steadily gained in importance and moved into the scientific focus. Understanding the three-dimensional arrangement of the face with its defined anatomical layers and compartments serves the procedural dermatologist in the sense of a navigation system to optimize treatment success and patient safety when performing aesthetic injections in the facial region. The principles of the biomechanical interaction of the structures are of elementary importance in the creation of individual treatment plans for the implementation of natural and balanced therapeutic results. Modern injection anatomy as an interdisciplinary subject of the three fields of anatomy, dermatology and plastic surgery makes a decisive contribution here.