Three-dimensional Facial Scans Research Articles

Modern approach to the treatment of postoperative symptoms of patients undergoing oral surgery

Introduction. Removal of wisdom teeth is always accompanied by the appearance of collateral edema of varying severity, pain, neurological dysfunction and inflammatory contracture of the masticatory muscles.Purpose. To evaluate the use of local apparatus hypothermia and the method of three-dimensional facial scanning for the treatment of patients after extraction of mandibular third molars.Materials and methods. 60 patients had their wisdom teeth removed. Depending on the group, local apparatus hypothermia (LAH) (study group of 30 patients) and local ice hypothermia (LIH) (control group of 30 patients) were performed after surgery. Evaluation criterion: three-dimensional scanning of the face on days 3, 5, 7.Results. In the control group, on the 3rd day the size of the edema was 6.31 mm (SD 0.81), on the 5th day – 4.88 mm (SD 0.73), on the 7th day – 3.44 mm (SD 0.88). In the study group, on the 3rd day the size of the edema was 5.09 mm (SD 0.80), on the 5th day – 2.73 mm (SD 0.71), on the 7th day – 1.28 mm (SD 0,62). In the control group, the size of edema on the 5th day changed by 22.67% compared to the 3rd day, on the 7th day by 30.12% compared to the 5th day and by 45.94% compared to 3rd day. In the study group, the size of edema on the 5th day changed by 46.42% compared to the 3rd day, on the 7th day by 53.16% compared to the 5th day and by 75.32% compared 3rd day. Comparison of groups 3, 5 and 7 in terms of absolute values of edema size and percentage change showed a statistically significant difference (p<0.001).Conclusion. The use of local apparatus hypothermia in the postoperative period can reduce the severity of collateral edema in a shorter period compared to standard methods of local hypothermia.

The Effects of a Cool Saline Solution Irrigation on Mandibular Third Molar Extraction Site: A Postoperative Split-Mouth Evaluation.

This study aimed to evaluate the effects of sterile saline solution irrigation (lavage) performed after mandibular third molar extraction on postoperative complications, utilizing a split-mouth randomized clinical trial design. Seventeen healthy participants requiring bilateral mandibular third molar extraction were enrolled in this single-center study. In each participant, one impacted third molar was designated as the experimental group and subjected to saline lavage at 4 °C. In contrast, the control group was the other impacted third molar, undergoing saline lavage at 25 °C. Various parameters, including postoperative pain, mouth opening, and facial swelling, were assessed using standardized measures and three-dimensional facial scanning at multiple time points. The average age of participants was 26.66 ± 4.1 years, with no postoperative complications observed in either group. The duration of surgery did not significantly differ between groups. Postoperative pain was significantly reduced in the experimental group during the immediate postoperative period compared with the control group, but this difference diminished over time. No significant differences were observed in mouth opening or facial swelling between groups at any time. In site 4 °C, sterile saline solution irrigation after mandibular third molar extraction may effectively reduce early postoperative complications, particularly pain, without prolonging surgical duration.

Does adjunctive fixation in conjunction with miniplate affect condylar position and morphology after mandibular advancement through bilateral sagittal split ramus osteotomy? A retrospective 3-dimensional CT comparative study

To minimize condylar positional and morphological changes after mandibular advancement through bilateral sagittal split ramus osteotomy (BSSRO), surgeons add either a bicortical screw or a two-hole plate distal to the conventional single miniplate. Since there have been no previous studies investigating the effect of this combination, our study aimed to evaluate the short- and long-term effects of these adjunctive fixation methods (AFM) on condylar positional and morphological changes after mandibular advancement through BSSRO.This retrospective cohort study included consecutive patients with retruded mandibles who were treated in the Department of Orthognathic and TMJ Surgery at West China Hospital of Stomatology, Sichuan University. The patients were divided into two groups based on the primary predictor variable, which was the addition of AFM — either a single bicortical screw or a two-hole plate in addition to the single miniplate. The primary outcome variable was the condylar positional and morphological changes after mandibular advancement through BSSRO. Three-dimensional facial CT scans were obtained at three different time points (preoperatively — T0, 1 week postoperatively — T1, and 1 year postoperatively — T2) and analyzed using ITK-SNAP, 3D Slicer, and SlicerSALT software. Intergroup comparisons were conducted with an independent t-test, with a p-value of <0.05 considered significant. Correlations between the variables were estimated by Pearson correlation. The study comprised 51 patients (32 females, 19 males; mean age 25.13 ± 4.24 years), involving a total of 81 condyles (21 unilateral and 60 bilateral).There was a significant difference in long-term condylar displacement in favor of AFM along with a single miniplate (p < 0.001). The bicortical screw group recorded less condylar displacement than the two-hole plate group horizontally (0.11 mm vs 0.22 mm) and sagittally (0.03 mm vs 0.17 mm), but more vertically (0.85 mm vs 0.03 mm). Bone formation associated with AFM occurred on all condylar surfaces, compared with only three surfaces in the single miniplate group.The adjunctive method in addition to the single miniplate fixation method showed less condylar displacement and more bone apposition after mandibular advancement through BSSRO. The follow-up duration variable was the only significant determinant for volumetric changes in the condyle.

Comparison of two 3D scanning software to identify facial features: a prospective instrument to predict difficult airway

BackgroundClinical airway assessment has limited predictive ability to anticipate difficult airway. Three-dimensional (3D) technologies have emerged in medicine as valuable tools in different settings including innovation and surgical planning. Three-dimensional facial scanning could add value to clinical measurements and two-dimensional models to assess the airway. However, commonly used high-fidelity scans are expensive. This study aims to compare the accuracy of the measurements made by the Scandy Pro app as a cost-effective alternative to high-fidelity scans made by the Artec Space Spider. We also aim to evaluate the interobserver variability for the measurements performed with Scandy Pro.Materials and methodsWe conducted a cross-sectional, comparison study on 10 healthy volunteers. Four observers measured 720 distances and 400 using both Scandy Pro and Artec Space Spider facial scans. Wilcoxon test was used for group–group comparison.ResultsComparison of both instruments showed no difference in angle or distance measurements. The percentage error (measurement difference between the two devices) exhibited by one of the observers was significantly different compared with the other three observers; however, the magnitude of this individual deviation did not affect the overall percentage error. The overall error for Scandy Pro was 5.5% (3.9% and 6.7% for angles and distances, respectively).ConclusionThree-dimensional facial scanning with Scandy Pro is an accurate tool that can be a cost-effective alternative to high-fidelity scans produced by the Artec Space Spider.

Validation of low-cost mobile phone applications and comparison with professional imaging systems for three-dimensional facial imaging: A pilot study

PurposeThe objective of this study was to investigate the accuracies of three-dimensional (3D) facial scanning mobile phone applications as compared to professional 3D facial imaging systems. Materials and MethodsA manikin head model was used as the subject for comparing six 3D facial imaging systems which comprised three professional 3D scanners (3dMDface, Artec Eva and Vectra H2) and three mobile phone applications (Bellus3D, ScandyPro and Hedges). For each system, five scans were taken to analyse (1) linear accuracy using 9 measurements (2) global and (3) regional 3D accuracy of the scanned surface by root mean square (RMS) and colour map analysis. Another set of five scans was repeated by a second operator to evaluate the inter-operator reproducibility for each system. ResultsAll the facial imaging systems had absolute errors lesser than 1.0 mm for the linear measurements. The technical error of measurement (TEM) for inter-examiner and intra-examiner linear measurements were within acceptable limits. Artec Eva, Vectra H2 and Scandy Pro had poor global 3D trueness (RMS > 1.0 mm) but good 3D regional trueness (RMS < 1.0 mm). 3dMDface, Bellus3D Face App and Heges had good global and regional 3D trueness. All the facial imaging systems had good global and regional 3D precision and reproducibility (RMS < 1.0 mm). ConclusionThis study demonstrated that mobile phone 3D scanning applications had comparable trueness, precision and reproducibility to professional systems. Colour map analysis supplemented the use of the RMS value to demonstrate facial regions of significant deviation. Clinicians should also consider the specific area or region of inaccuracies for each system to determine whether the chosen system is appropriate for the clinical condition or procedure. Clinical SignificanceMobile phone 3D facial imaging applications may be as accurate as 3D professional facial scanning systems for craniomaxillofacial purposes. However, the choice of the system may vary depending on the specific area of interest.

Geometric morphometrics and machine learning from three-dimensional facial scans for difficult mask ventilation prediction.

Unanticipated difficult mask ventilation (DMV) is a potentially life-threatening event in anesthesia. Nevertheless, predicting DMV currently remains a challenge. This study aimed to verify whether three dimensional (3D) facial scans could predict DMV in patients scheduled for general anesthesia. The 3D facial scans were taken on 669 adult patients scheduled for elective surgery under general anesthesia. Clinical variables currently used as predictors of DMV were also collected. The DMV was defined as the inability to provide adequate and stable ventilation. Spatially dense landmarks were digitized on 3D scans to describe sufficient details for facial features and then processed by 3D geometric morphometrics. Ten different machine learning (ML) algorithms, varying from simple to more advanced, were introduced. The performance of ML models for DMV prediction was compared with that of the DIFFMASK score. The area under the receiver operating characteristic curves (AUC) with its 95% confidence interval (95% CI) as well as the specificity and sensitivity were used to evaluate the predictive value of the model. The incidence of DMV was 35/669 (5.23%). The logistic regression (LR) model performed best among the 10 ML models. The AUC of the LR model was 0.825 (95% CI, 0.765-0.885). The sensitivity and specificity of the model were 0.829 (95% CI, 0.629-0.914) and 0.733 (95% CI, 0.532-0.819), respectively. The LR model demonstrated better predictive performance than the DIFFMASK score, which obtained an AUC of 0.785 (95% CI, 0.710-0.860) and a sensitivity of 0.686 (95% CI, 0.578-0.847). Notably, we identified a significant morphological difference in the mandibular region between the DMV group and the easy mask ventilation group. Our study indicated a distinct morphological difference in the mandibular region between the DMV group and the easy mask ventilation group. 3D geometric morphometrics with ML could be a rapid, efficient, and non-invasive tool for DMV prediction to improve anesthesia safety.

WITHDRAWN: Accuracy and reproducibility of tablet-based applications for three-dimensional facial scanning: an in-vitro study.

This article has been withdrawn at the request ot the author(s).

"Application of the Wilson-Richmond Categorisation Tool on Three-Dimensional Facial Scans of a Population of 12-Year Old Welsh Children"

"Application of the Wilson-Richmond Categorisation Tool on Three-Dimensional Facial Scans of a Population of 12-Year Old Welsh Children"

Accuracy (trueness and precision) of four tablet-based applications for three-dimensional facial scanning: An in-vitro study

ObjectivesThis study aimed to investigate the overall and regional accuracy (trueness and precision) of digital three-dimensional (3D) facial scans obtained from four tablet-based applications, which were (Bellus) the Bellus Dental Pro® (Bellus3D, Inc. Campbell, CA, USA), (Capture) the Capture®: 3D Scan Anything (Standard Cyborg, Inc. San Francisco, CA, USA), (Heges) the Heges® (by Marek Simonik, Ostrava, North Moravia, Czech Republic), and (Scandy) the Scandy Pro 3D Scanner® (Scandy LLC, New Orleans, LA, USA). MethodsA mannequin's face was marked with 63 landmarks. Subsequently, it was scanned 5 times using each scan application on an iPad Pro® (Apple Inc., Cupertino, CA, USA). The digital measurements were obtained with MeshLab® (CNR-ISTI, Pisa, Tuscany, Italy) and compared to the manual measurements using a digital vernier calliper (Truper Herramientas S.A., Colonia Granada, Mexico City, Mexico). The absolute mean difference and the standard deviation of the dimensional discrepancies were calculated. Moreover, the data were analysed by using one-way ANOVA, Levene's test, and Bonferroni´s correction. ResultsThe absolute mean trueness values were Bellus 0.41 ± 0.35 mm, Capture 0.38 ± 0.37 mm, Heges 0.39 ± 0.38 mm, and Scandy 0.47 ± 0.44 mm. Moreover, precision values were Bellus 0.46 mm, Capture 0.46 mm, Heges 0.54 mm, and Scandy 0.64 mm. Comparing the regions, Capture and Scandy showed the highest absolute mean difference, which was 0.81 mm in the Frontal and Zygomaticofacial regions, respectively. ConclusionsThe trueness and precision of all four tablet-based applications were clinically acceptable for diagnosis and treatment planning. Clinical significanceThe future of the three-dimensional facial scan is auspicious, and it has the potential to be affordable, accurate, and of great value for clinicians in their daily practice.

THREE-DIMENSIONAL SCANNING IN RHINOPLASTY AND INDIVIDUAL PATIENT EXPERIENCE

Introduction: Three-dimensional facial scanning has been the object of study for decades and increasingly being used in rhinoplasty, and has recently been applied to surgical simulation. The patient’s perspective in this context should be explored, so that surgeons can individualize their approach. Objectives: Acess the patient’s perspective on three-dimensional scanning in rhinoplasty and their experience during the evaluation and simulation processes in preoperative consultation. Material and methods: Longitudinal, prospective and qualitative study, with the application of a questionnaire to patients who searched for rhinoplasty, during the preoperative consultation after obtaining images through 3D scanning and case simulation. Results: All participants agreed that three-dimensional scanning optimizes patient-surgeon communication; that it should become routine in the preoperative evaluation of cosmetic surgeries; and they felt more confident about the surgery after this process. None of the interviewees mentioned discomfort while obtaining the images. More than 60% were surprised by the images obtained by the three-dimensional facial scanning and by the result of the simulation. Discussion: The use of computerized imaging in the preoperative consultation transforms patients from passive listeners to active participants, who express their intentions and are involved in the discussion of the objectives of the surgery to which they will be submitted. Reservations regarding cost, additional time, and increased patient expectations must be considered. Conclusion: Three-dimensional facial scanning is an additional tool in the rhinoplasty preoperative period, bringing benefits to the communication and relationship between physicians and patients.

Intra- and Interrater Agreement of Face Esthetic Analysis in 3D Face Images.

The use of three-dimensional (3D) facial scans for facial analysis is increasing in maxillofacial treatment. The aim of this study was to investigate the consistency of two-dimensional (2D) and 3D facial analyses performed by multiple raters. Six men and four women (25-36-year-old) participated in this study. The 2D images of the smiling and resting faces in the frontal and sagittal planes were obtained. The 3D facial and intraoral scans were merged to generate virtual 3D faces. Ten clinicians performed facial analyses by investigating 14 indices of 2D and 3D faces. Intra- and interrater agreements of the results of 2D and 3D facial analyses within and among the participants were evaluated. The intrarater agreement between the 2D and 3D facial analyses varied according to the indices. The highest and lowest agreements were found for the dental crowding index (0.94) and smile line curvature index (0.56) in the frontal plane, and Angle's classification (canine) index (0.98) and occlusal plane angle index (0.55) in the profile plane. In the frontal plane, the interrater agreements were generally higher for the 3D images than for the 2D images, while in the profile plane, the interrater agreements were high in the Angle's classification (canine) index however low in the other indices. Several occlusion-related indices were missing in the 2D images because the posterior teeth were not observed. Esthetic analysis results between 2D and 3D face images can differ according to the evaluation indices. The use of 3D faces is recommended over 2D images to increase the reliability of facial analyses, as it can fully assess both esthetic and occlusion-related indices.

The association between dental and facial symmetry in adolescents

Facial aesthetics have become one of the most important objectives of orthodontic treatment. The correction of dental arches should be performed in accordance with the face. This study explored the association between occlusal and facial asymmetries in adolescents, particularly emphasizing a Class II subdivision. Eighty-one adolescents (43 males, 38 females) with a median age of 15.9 (interquartile range, 15.17-16.33) years were enrolled. Of these patients, 30 had a Class II subdivision (right side, n= 12; left side, n= 18). Three-dimensional facial scans were analyzed using surface- and landmark-based methods. Chin asymmetry was determined using the chin volume asymmetry score. Three-dimensional intraoral scans were analyzed to assess occlusal asymmetry. The surface matching scores were 59.0% ± 11.3% for the whole face and 39.0% ± 19.2% for the chin. Chin volume was larger on the right side than on the left side in most patients (n= 51, 63%), and it was associated with a dental midline shift to the corresponding subdivision side. A correlation between dental and facial asymmetries was noted. In addition, the dental midline shifted to the left in patients with a Class II subdivision, regardless of the side, and to the right in those with a symmetrical Class II subdivision. However, several patients did not possess asymmetrical occlusal traits sufficient for statistical analysis. Dental asymmetry was weak but significantly correlated with facial asymmetry.

Three-dimensional evaluation of the association between face and back asymmetry among pre-pubertal subjects.

The aim was to compare the degree of back symmetry in two groups of subjects with and without pathologic facial asymmetry and to assess any possible associations between face and back asymmetry evaluated on three-dimensional surface face and back scans. The study design consisted of allocation of 70 subjects (35 females, 35 males) aged 6.4±0.5 years, according to the percentage of whole face symmetry assessed on three-dimensional (3D) facial scans into a 'symmetric' (symG; symmetry ≥70%) and 'asymmetric'(asymG; symmetry <70%). The 3D face and back scans were analysed using colour deviation maps and percentages of symmetry of the whole face and back surfaces as well as their three separate areas: forehead, maxillary and mandibular areas for the face and neck, upper and middle trunk areas for the back, were calculated. Non-parametric statistical tests were used for between-group comparisons (Mann-Whitney U test). Within each group, differences between each face or back area were tested with the Friedman test. Correlations between face and back symmetry were assessed with the Spearman rho coefficient. The symG exhibited a significantly higher symmetry in each facial area than the asymG. The mandibular area was the least symmetric area of the face within each group, with significantly smaller values than the maxillary area in the symG and significantly smaller values than the forehead and maxillary area in the asymG. The percentage of whole back symmetry did not significantly differ (p>0.05) between the symG ( 82.00% [67.4;88.00]) and asymG (74.3% [66.1;79.6]). The only significant between-group difference was observed for the symmetry of the upper trunk area (p=0.021), with lower symmetry values in the asymG. No significant associations were detected between face and back parameters. The percentages of symmetry in each facial area were significantly higher among subjects without pathologic facial asymmetry. The most asymmetric area of the face, regardless of the degree of whole face symmetry, was its mandibular area. No significant differences were detected within different back areas; however, subjects with asymmetric faces showed significantly smaller symmetry of their upper trunk area.

Development of a Customized Mask Frame Using a Three-Dimensional Facial Scan for an Airtight Seal for Disposable Surgical Face Masks

Abstract Disposable surgical face masks are designed to block the airborne transmission of infectious viruses between patients and healthcare personnel; however, there are limitations to a surgical mask's ability to prevent transmissions because the mask does not provide an airtight seal around the face. This study focuses on the design and development of a custom mask frame, using individuals' three-dimensional (3D) facial scans, to improve the seal of the existing surgical masks. Three participants' facial scans with a wide range of facial dimensions were collected using a 3D hand-held scanner. During design, the contact area between the custom frame and the wearer's skin was determined based on the individual's 3D facial shape. To evaluate the effectiveness of the airtight seal, a qualitative fit (smell/taste) test kit and thermal imaging camera were utilized. When the participants wore the surgical masks without the customized mask frames, the participants smelled the saccharine scent from the test kit. However, while wearing the surgical masks fitted with the custom mask frame that held the mask in place, none of the participants could smell the scent. In addition, thermal images showed ambient temperature changes in the surgical mask suggesting air leakage around the boundary of the mask while the subject was inhaling and exhaling. With the mask frame, thermal images confirmed the effectiveness of the custom frame to block the inflow/outflow of air potentially carrying the virus. The results indicate that the custom-built mask frames are effective in providing a proper and much improved seal compared to a surgical mask without the frame. The developed custom mask frame will be particularly beneficial for frontline medical staff members who treat patients with infectious viruses transmitted through aerosols as part of their PPE.

A digital workflow to predict facial aesthetics in patients with maxillofacial trauma with implant retained prostheses.

Purpose To introduce a digital workflow for the prediction of facial aesthetics, especially in patients with dentation deformity caused by maxillofacial trauma.Methods Cone-beam computed tomography (CBCT) and three-dimensional facial scans of patients with radiographic prostheses were collected. The aforementioned data were uploaded to ProPlan CMF software and merged to generate a virtual patient with craniofacial hard tissue, realistic facial soft tissue, and remaining dentition. The radiographic prostheses were scanned to form a digital cast, which was fitted with its CBCT image to create the virtual prostheses. Postoperative facial soft tissue was simulated according to the movement of the virtual prostheses. An appropriate virtual diagnostic prosthesis plan was selected by the patient and dentist. Subsequently, prosthetically driven implant guide and restoration were designed and fabricated.Conclusions A virtual patient was successfully constructed. A 4-mm protrusion of the virtual prosthesis was chosen. Subsequently, implant surgery was performed, and dental prostheses were fabricated based on this location. The fusion of the postoperative facial scan and preoperative facial prediction was found to be coincident. This technique can effectively predict facial aesthetic features of patients with maxillofacial trauma, facilitate communication with patients, reduce chairside time, and guide the multidisciplinary design of implant placement and restoration fabrication.

Anthropometric Comparison of 3-Dimensional Facial Scan Taken With a Low-Cost Facial Scanner With Cone-Beam Computed Tomography Scan.

The aim of this study was to evaluate the accuracy of 3-dimensional (3D) facial scans taken with a low-cost facial scanner compared with cone-beam computed tomography (CBCT). Twenty-five patients had their CBCT scan and 3D facial scan taken on the same day. Facial scans were taken with a low-cost facial scanner (Bellus3D, ARC-1 scanner) in an upright position. The facial scans were imported into Invivo5 software and were integrated with the corresponding CBCT scans. Then, 16 soft tissue landmarks were identified on the CBCT scans and the 3D-integrated facial scans. The 6 vertical, 7 horizontal, 10 oblique linear, and 11 angular anthropometric measurements were obtained and compared between the CBCT scans and 3D-integrated facial scans using paired t test and Bland-Altman plots. The differences between CBCT scans and 3D-integrated facial scans showed no statistical significance except for 2 vertical measurements. Bland-Altman plots showed that all anthropometric measurements were within the limit of agreement. The differences between CBCT scans and 3D-integrated facial scans were <1.5mm or 1.5 degrees except for 2 vertical measurements. Three-dimensional facial scans taken with facial scanner showed a clinical acceptance when compared with CBCT scans.

Integration accuracy of craniofacial cone-beam computed tomography images with three-dimensional facial scans according to different registration areas.

To evaluate the integration accuracy of cone-beam computed tomography (CBCT) images with three-dimensional (3D) facial scans according to different registration areas. Twenty-five patients (14 males and 11 females), with a mean age of 19.0 ± 11.3 years, were included in this study. Each patient underwent CBCT and facial scans on the same day in an upright position. The facial scans were integrated with the corresponding soft-tissue images of CBCT scans. Three methods were used to integrate the two imaging modalities based on the facial regions scanned: R1, only the forehead and nasal bridge area were included; R2, the right and left malar area were included; and R3, the forehead, nasal bridge, and malar areas were included. The integration accuracy between the facial scans and CBCT images was evaluated by color-mapping methods and average surface distances, calculated by measuring the 3D distances between the surface points on the two superimposed images. The average surface differences between facial scans and CBCT images were less than 1.0 mm in all three methods. The R3 method showed fewer differences between the facial scans and CBCT images than the other methods did. Facial scans obtained using a low-cost facial scanner showed clinically acceptable performance. The integration accuracy of facial and CBCT scans can be increased by including the forehead, nasal bridge, and malar areas as registration areas.

Novel Method for Three-Dimensional Facial Expression Recognition Using Self-Normalizing Neural Networks and Mobile Devices.

Introduction To date, most ways to perform facial expression recognition rely on two-dimensional images, advanced approaches with three-dimensional data exist. These however demand stationary apparatuses and thus lack portability and possibilities to scale deployment. As human emotions, intent and even diseases may condense in distinct facial expressions or changes therein, the need for a portable yet capable solution is signified. Due to the superior informative value of three-dimensional data on facial morphology and because certain syndromes find expression in specific facial dysmorphisms, a solution should allow portable acquisition of true three-dimensional facial scans in real time. In this study we present a novel solution for the three-dimensional acquisition of facial geometry data and the recognition of facial expressions from it. The new technology presented here only requires the use of a smartphone or tablet with an integrated TrueDepth camera and enables real-time acquisition of the geometry and its categorization into distinct facial expressions. Material and Methods Our approach consisted of two parts: First, training data was acquired by asking a collective of 226 medical students to adopt defined facial expressions while their current facial morphology was captured by our specially developed app running on iPads, placed in front of the students. In total, the list of the facial expressions to be shown by the participants consisted of “disappointed”, “stressed”, “happy”, “sad” and “surprised”. Second, the data were used to train a self-normalizing neural network. A set of all factors describing the current facial expression at a time is referred to as “snapshot”. Results In total, over half a million snapshots were recorded in the study. Ultimately, the network achieved an overall accuracy of 80.54% after 400 epochs of training. In test, an overall accuracy of 81.15% was determined. Recall values differed by the category of a snapshot and ranged from 74.79% for “stressed” to 87.61% for “happy”. Precision showed similar results, whereas “sad” achieved the lowest value at 77.48% and “surprised” the highest at 86.87%. Conclusions With the present work it can be demonstrated that respectable results can be achieved even when using data sets with some challenges. Through various measures, already incorporated into an optimized version of our app, it is to be expected that the training results can be significantly improved and made more precise in the future. Currently a follow-up study with the new version of our app that encompasses the suggested alterations and adaptions, is being conducted. We aim to build a large and open database of facial scans not only for facial expression recognition but to perform disease recognition and to monitor diseases’ treatment progresses.

A Modified Technique in Rhinoplasty: A Septal Extension Graft Complex Using Septal Cartilage, Ethmoid Bone, and Auricular Cartilage.

Due to the small and weak septal cartilage of Asians, it is a challenge to obtain ideal tip projection and nose lengthening in this population by performing septal extension grafts with only septal cartilage. The aim of this study was to introduce a septal extension graft complex incorporating nasal septal cartilage, the perpendicular plate of the ethmoid bone, and bilateral auricular cartilage, and to examine its effectiveness in terms of morphological and mechanical support. Septal cartilage was harvested under an endoscope according to standard techniques. Two pieces of the perpendicular plate of the ethmoid bone, placed on either side of the "L" strut, served as 2 spreader grafts. A double layer of auricular cartilage was fixed as columellar strut grafts. Three-dimensional facial scanning was used to examine the change of 3 parameters. Nasal tip resistance was evaluated by a digital Newton meter. In total, 25 patients were followed up postoperatively for a mean of 25.9 months. The analysis showed significant differences in both contour parameters and nasal resistance: nasal length (mean [standard deviation], 41.4 [4.0] vs 46.2 [3.4] mm, P < 0.05) and nasal tip projection (21.3 [3.2] vs 24.4 [2.7] mm, P < 0.05) appeared to increase postoperatively, whereas nasolabial angle (117.6° [5.9°] vs 109.5° [5.3°], P < 0.05) showed a significant decrease after surgery. The resistance of the nasal tip also increased significantly (P < 0.05) at displacements of 1, 2, and 3 mm. All patients were satisfied with the aesthetic results, and no serious complications occurred. This kind of modified septal extension graft technique can effectively adjust nasal morphology for short-nose East Asians.

Trueness of One Stationary and Two Mobile Systems for Three-Dimensional Facial Scanning.

To evaluate the trueness of one stationary and two mobile systems for 3D facial scanning. Twenty participants were included in this study. After marking facial soft tissue landmarks, their faces were scanned using three facial scanning systems: the Bellus3D Dental Pro app on an iPad Pro 2020 (Apple; IP); the ARC-7 Face Scanning System (Bellus3D; BA); and the EinScan Pro 2X Plus (Shining 3D Tech; EP) following the manufacturers' operating instructions. Three-dimensional images were reconstructed with corresponding software and saved in object (OBJ) file format. The interlandmark distances were measured and compared to direct caliper measurements, and absolute error (AE) was chosen as the measurement to determine the trueness of the three scanners. The normal distribution and variance of homogeneity were measured, and then the data were analyzed using one-way ANOVA or Kruskal-Wallis H test. The significance level was set at P = .05. For the measurement of interlandmark distances, no significant differences were found among the four measuring techniques, and the mean AEs of the IP, BA, and EP systems were 1.17 ± 0.80 mm, 0.76 ± 0.61 mm, and 0.69 ± 0.65 mm. The three facial scanning systems tested provided a reliable 3D facial reconstruction. The portable IP system could meet the clinical requirements for facial scanning, but it is suggested to select the EP and BA systems when a higher trueness is required.