Comparison of three methods of facial measurement

Ergonomic compatibility between sewing workstation and Bangladeshi apparel workers

Prolonged sitting with awkward posture during sewing results in musculoskeletal disorders among sewing operators. This study aimed to identify the compatibility of the sewing furniture with operators' anthropometry. Therefore, 13 anthropometric measurements of 368 sewing operators were collected and compared with sewing furniture dimensions. The results showed that all anthropometric measurements other than hip breadth were larger for male participants. In addition, statistical analysis performed on the collected data showed significant variation compared to the existing dimensions of sewing machines. Results also indicated a high mismatch for different dimensions of the sewing table and chair, such as seat height, seat width, seat depth, table depth, etc. For this reason, sewing operators often experience musculoskeletal disorders. Finally, this study recommends some guidelines for designing the sewing workstation, which might act as a basis for manufacturers or importers to set provisions for sewing machines.

3D evaluation of cranial and dentofacial morphological differences between individuals with mouth breathing and nasal breathing

INTRODUCTION

The present study aimed to identify the morphological differences in cranial and dentofacial structures between individuals with mouth-breathing and nasal-breathing.

MATERIALS AND METHODS

The study included 120 individuals, 60 each in the nasal breathing (NB) and mouth breathing (MB) groups. 3D stereophotogrammetry, lateral cephalometric radiographs, and intraoral examination results were recorded by the researchers to determine the morphological differences between the MB group and the NB group. The study utilized cephalometric radiographs for 2D hard tissue measurements and 3D stereophotogrammetric records for linear and angular measurements.

RESULTS

Statistically significant differences were found between the NB and MB groups' SNB angles (respectively, 79.3 ± 3.04, 76.6 ± 4.24, and p=0.002). Also, the NB group's SN-GoGn angle was lower than the MB group's (respectively, 31.5 ± 5.12, 36.0 ± 5.55, and p=0.002). Considering the Jarabak ratio, the NB group's Jarabak ratio was higher than the MB group (respectively,65.7 ± 4.16, 62.6 ± 4.10, and p=0.014). In 3D stereophotogrammetry measurements, increased Li-Me' was detected in the MB group than in NB group.

CONCLUSION

Mouth breathing results in significant morphological differences that affect the development of both soft tissues and skeletal structures. Orthodontists utilize these characteristic features observed in mouth-breathing anomalies for early diagnosis and consider referring their patients for medical treatment of mouth breathing.

"Utility of Smartphone-based Three-dimensional Surface Imaging for Digital Facial Anthropometry"

Background

The utilization of three-dimensional (3D) surface imaging for facial anthropometry is a significant asset for patients undergoing maxillofacial surgery. Notably, there have been recent advancements in smartphone technology that enable 3D surface imaging.In this study, anthropometric assessments of the face were performed using a smartphone and a sophisticated 3D surface imaging system.

Methods

30 healthy volunteers (15 females and 15 males) were included in the study. An iPhone 14 Pro (Apple Inc., USA) using the application 3D Scanner App (Laan Consulting Corp., USA) and the Vectra M5 (Canfield Scientific, USA) were employed to create 3D surface models. For each participant, 19 anthropometric measurements were conducted on the 3D surface models. Subsequently, the anthropometric measurements generated by the two approaches were compared. The statistical techniques employed included the paired t-test, paired Wilcoxon signed-rank test, Bland-Altman analysis, and calculation of the intraclass correlation coefficient (ICC).

Results

All measurements showed excellent agreement between smartphone-based and Vectra M5-based measurements (ICC between 0.85 and 0.97). Statistical analysis revealed no statistically significant differences in the central tendencies for 17 of the 19 linear measurements. Despite the excellent agreement found, Bland-Altman analysis revealed that the 95% limits of agreement between the two methods exceeded ±3 mm for the majority of measurements.

Conclusion

Digital facial anthropometry using smartphones can serve as a valuable supplementary tool for surgeons, enhancing their communication with patients. However, the proposed data suggest that digital facial anthropometry using smartphones may not yet be suitable for certain diagnostic purposes that require high accuracy.

Current status of optical scanning in facial prosthetics: A systematic review and meta-analysis

Purpose To assess the accuracy of scanning technologies for constructing facial prostheses on human faces.Study selection Our systematic search was performed on five databases. Studies reporting on human volunteers (P) whose faces were scanned with a scanning technology were eligible. The anthropometrical interlandmark distances (ILDs) were used as indicators of accuracy; the ILDs are measured on the virtual models (I) and directly on the faces (C). The virtual models deviated from their true values (O). Studies reporting the measurements on patients with or without facial deformities were included, but cadavers or inanimate objects were reasons for exclusion. We performed a mean difference (MD) / standardized MD analysis with a random effect model. The difficulties regarding the scanning procedure mentioned in the articles were also assessed.Results We found 3723 records after duplicate removal. Twenty five articles were eligible for the qualitative review, and ten articles were included in the quantitative synthesis. Eight different ILDs were compared in MD analyses. The differences were between -0.54-0.43 mm. We also performed a regional three-dimensional analysis to compare scanning technologies in each major region. No significant differences were found in any of the regions and axes. The most mentioned difficulties were artifacts due to motion or blinking.Conclusions The results suggest no systematic skew in linear dimensions neither between direct caliper measurements nor between measurements on the scanned models, scanning technologies, or facial regions.

Is There a Need for Greater Emphasis on Clinical Facial Analysis than Cephalometrics & 3D Software Solutions in the Diagnosis and Treatment Planning of Patients with Dentofacial Deformities?

Purpose

This study is designed to evaluate the need for a greater emphasis on clinical facial analysis over cephalometrics in the diagnosis and treatment planning of patients with dentofacial deformities.

Materials and Method

A predetermined questionnaire study was designed to get the thought process of surgeons and consultants involved in orthognathic surgery from various parts of southern India. Two hundred and twenty-eight maxillofacial consultants were involved in the survey. Demographic information, type of professional practice, preferred tool in the diagnosis & treatment planning: Cephalometrics or 3D software solutions and flaw in the available tools were evaluated.

Results

The results of this study revealed that only 36.8% of the consultants felt that cephalometrics is the prime tool and 73.3% of the consultants felt that 3D software solutions were superior to cephalometrics in the diagnosis and treatment planning of patients with dentofacial deformities. However, 46% of the consultants preferred facial analysis as the prime tool with cephalometrics as an adjunct. Pertaining to the clinical outcome of their treated cases of dentofacial deformities, 61.8% of the consultants felt the need to address additional cosmetic issues following an orthognathic procedure. It was observed that 92.1% of the participants felt the need for greater emphasis on clinical facial analysis than cephalometrics.

Conclusion

Human faces should always be evaluated taking into consideration the various esthetic units of the face. Performing corrective jaw surgery merely based on cephalometric values inevitably fails to address the various other innate imbalances of the face. Hence, cephalometric data should only be considered as an adjunct to clinical judgment in the diagnosis and treatment planning of dentofacial deformities.

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.

Assessment of the reproducibility and accuracy of the Visia® Complexion Analysis Camera System for objective skin analysis of facial wrinkles and skin age

Objective

This study aimed to investigate the reproducibility and accuracy of the Visia® Complexion Analysis Camera System by Canfield Scientific for objective skin analysis.

Methods

Nineteen participants underwent facial capture with the Visia® camera following a standardised protocol. During the first session, the participants sat down and positioned their faces in a capture rig, closed their eyes and had their faces captured from the left, front and right sides, with threefold repetition of the captures from the front side. After 4 weeks, the participants underwent recapture in a similar manner. Based on the frontal views, data for two measurement methods of the Visia® camera system, the absolute scores and the percentiles, were obtained with regard to the skin criterion wrinkles via automated software calculation. Means and standard deviations were evaluated. Based on the side views, the data for the Truskin Ages® were calculated by the Visia® camera system and compared with the calendrical ages, which served as the gold standard for comparison.

Results

In the assessment of the reproducibility of the data of the capture system the standard deviation from the frontal captures among all participants was about 3% when the absolute scores of the wrinkles were compared with each other; specifically, the average deviation was 3.36% during the first capture session and 3.4% during the second capture session. Meanwhile, the standard deviation of the measurements was about 9% when the percentiles were compared; specifically, the average deviation was 8.2% during the first capture session and 10.7% during the second capture session. In the assessment of the accuracy the correlation between the calendrical age and the calculated Truskin Age® for both facial sides was very high at a correlation coefficient rho value of >0.8 (right side: r=0.896; left side: r=0.827) and statistically significant at a p-value of <0.001. The average calendrical age and Truskin Age® deviated only slightly from each other and did not differ significantly (right side: p=0.174; left side: p=0.190). The Truskin Age® was slightly higher than the calendrical age by a mean value of 1.37 years for both facial sides. The analysis of the absolute differences revealed that in 50% of the cases, there was a maximum difference of 3 years, and in 75% of the cases, there were maximum differences of 4.5 years for the right side and 5.5 years for the left side.

Conclusion

The assessment of the reproducibility and accuracy of the objective measurement method, the Visia® camera system, contributed to the validation of the system. The evaluation of the reproducibility revealed a satisfactory precision of the repeated captures when investigating facial wrinkles. Absolute scores should be preferred over percentiles owing to their better precision. The calculation of the accuracy of the Truskin Age® data from the Visia® camera system revealed only a slight deviation from the true calendrical ages. The correlation between both data groups was highly significant.

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

PURPOSE

The 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 METHODS

A 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.

RESULTS

All 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).

CONCLUSION

This 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 SIGNIFICANCE

Mobile 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.

Accuracy and Reliability of 3D Imaging for Facial Movement Evaluation: Validation of the VECTRA H1

Three-dimensional imaging can be used to obtain objective assessments of facial morphology that is useful in a variety of clinical settings. The VECTRA H1 is unique in that it is relatively inexpensive, handheld, and does not require standardized environmental conditions for image capture. Although it provides accurate measurements when imaging relaxed facial expressions, the clinical evaluation of many disorders involves the assessment of facial morphology when performing facial movements. The aim of this study was to assess the accuracy and reliability of the VECTRA H1, specifically when imaging facial movement.

Methods

The accuracy, intrarater, and interrater reliability of the VECTRA H1 were assessed when imaging four facial expressions: eyebrow lift, smile, snarl, and lip pucker. Fourteen healthy adult subjects had the distances between 13 fiducial facial landmarks measured at rest and the terminal point of each of the four movements by digital caliper and by the VECTRA H1. Intraclass correlation and Bland-Altman limits of agreement were used to determine agreement between measures. The agreement between measurements obtained by five different reviewers was evaluated by intraclass correlation to determine interrater reliability.

Results

Median correlation between digital caliper and VECTRA H1 measurements ranged from 0.907 (snarl) to 0.921 (smile). Median correlation was very good for both intrarater (0.960-0.975) and interrater reliability (0.997-0.999). The mean absolute error between modalities, and both within and between raters was less than 2 mm for all movements tested.

Conclusion

The VECTRA H1 met acceptable standards for the assessment of facial morphology when imaging facial movements.

The Average Facial Expressions: A Range of Motion Analysis for Different Sex and Age Groups

Facial expressions are ubiquitous in communication. Therefore, assessment of mimic function is essential in facial surgery, but no reference standards are currently available. This prospective study aims to create reference values of three-dimensional landmark displacement for different sex and age groups.

Methods

Three-dimensional photographs were taken from healthy subjects in rest, maximum closed smile, and pouting. Displacement for both exercises of perioral landmarks was analyzed with MATLAB as absolute displacement and as the ratio of mouth width. Additionally, displacement in three planes was analyzed for each landmark. Averages were calculated for both genders in four age groups: 4-8, 8-12, 12-16, and >16 years.

Results

In total, 328 subjects were included. Oral landmarks predominantly moved forward and backward for both exercises. Nasal landmarks predominantly moved vertically. Growing up, oral landmark displacement decreased for smiling, whereas nasal landmark displacement increased. For pouting, oral landmark displacement increased while growing up, whereas nasal landmark displacement decreased.

Conclusions

The present study creates reference values for movement of perioral structures for different sex and age groups, for two facial expressions. These data are of great value for the assessment of mimic function and give insight into the development of facial animation over time.

The average three-dimensional face for different sex and age groups in a Dutch population

The increasing use of three-dimensional imaging calls for reference models representing large parts of the population. The aim of this prospective study was to create templates depicting facial maturation in the younger age groups. Healthy Dutch volunteers were captured, without selection of inclusions. Three-dimensional average faces were created using MATLAB, for both genders in four age groups (4-8 years, 8-12 years, 12-16 years, and ≥16 years). Variation within the groups was calculated and depicted on an average face with a green to red colour scale, corresponding to standard deviations between 0 and ≥ 3 mm, respectively. Measurements of the distances of eight peri-oral landmarks were provided as ratios. The statistical analysis was performed using ANOVA and Tukey's test. Three-dimensional reconstructions of the average face and their first principal component were created for each gender and age group. The first principal component comprised the facial width for each group, and the variation of landmarks was low. All ratios showed an increasing trend with increasing age, except for the ratio of philtrum width to mouth width. This study is novel in comparing facial morphology by means of ratios and in creating average faces for the different young age groups. These data provide useful insights into facial maturation, which might be beneficial for facial surgeons.

The Science Behind Nefertiti's Beauty: A Plastic Surgeon's Analysis

Introduction  The famous stucco limestone coated "Bust of Nefertiti" housed in the Neues Museum, Germany dated 1,345 BC is an icon of beauty. Sculpted around three millennia ago by Thutmose, the bust still emits a charm that leaves its audience spellbound. However, no one, to the best of author's knowledge, has analyzed this sculpture or its photographs objectively to determine if there is any scientific basis to its attractiveness. Materials and Methods  High-resolution photographs of the bust were anthropometrically analyzed in frontal and right lateral profile views using neoclassical canons and Farkas' studies. Results  The photographs of the bust exhibit many of the neoclassical canons and proportions of Farkas' studies exactly, while many of the remaining are very close to these measurements. A few measurements are out of range of what is considered acceptable these days; however, her overall appearance is pleasing. Conclusion  Despite passage of more than three millennia, the proportions and parameters defining beautiful faces have largely remained unchanged.

Application of 3D Imaging-Assisted Precise Aesthetic Evaluation in Midfacial Depression Treatment

Most Chinese have unpleasant facial profile of midfacial depression, which could be caused by multiple reasons. In the past, LeFort osteotomy and orthodontic methods were applied for surgical treatment of midfacial concavity. As the development of plastic surgery filling techniques, nasal base filling or concurrent comprehensive rhinoplasty has been widely used to improve midfacial depression. However, most of the related studies focus on surgical techniques or filling materials, yet lack accurate and objective aesthetic evaluation. In the current study, we used 3D imaging to collect 3D facial profile of 66 patients suffering from midfacial depression. Related linear distance and angles were measured accurately using 3D software. Patient satisfaction and physician evaluation were also collected in the follow-up period. The results showed that patients' midfacial depression were significantly improved after the surgery and the overall patient satisfaction was 100%. Our study demonstrated the positive role of nasal base filling in improving the midfacial depression, and illustrated the advantages of 3D imaging technology in personalized preoperative communication, surgical simulation and postoperative effect evaluation.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 .

Accuracy of three-dimensional optical devices for facial soft-tissue measurement in clinical practice of stomatology: A PRISMA systematic review

BACKGROUND

The accuracy of 3-dimensional (3D) optical devices for facial soft-tissue measurement is essential to the success of clinical treatment in stomatology. The aim of the present systematic review was to summarize the accuracy of 3D optical devices used for facial soft-tissue assessment in stomatology.

METHODS

An extensive systematic literature search was performed in the PubMed/MEDLINE, Embase, Scopus and Cochrane Library databases for studies published in the English language up to May 2022 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Peer-reviewed journal articles evaluating the facial soft-tissue morphology by 3D optical devices were included. The risk of bias was performed using the Quality Assessment Tool for Diagnostic Accuracy Studies-2 guidelines by the 2 reviewers. The potential publication bias was analyzed using the Review Manager software.

RESULTS

The query returned 1853 results. A total of 38 studies were included in this review. Articles were categorized based on the principle of devices: laser-based scanning, structured-light scanning, stereophotogrammetry and red, green, blue-depth camera.

CONCLUSION

Overall, the 3D optical devices demonstrated excellent accuracy and reliability for facial soft-tissue measurement in stomatology. red, green, blue-depth camera can collect accurate static and dynamic 3D facial scans with low cost and high measurement accuracy. Practical needs and availability of resources should be considered when these devices are used in clinical settings.

Facial scanning technologies in the era of digital workflow: A systematic review and network meta-analysis

PURPOSE

The aim of this network meta-analysis is to evaluate the accuracy of various face-scanning technologies in the market, with respect to the different dimensions of space (x, y, and z axes). Furthermore, attention will be paid to the type of technologies currently used and to the best practices for high-quality scan acquisition.

MATERIAL AND METHODS

The review was conducted following the PRISMA guidelines and its updates. A thorough search was performed using the digital databases MEDLINE, PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials by entering research lines or various combinations of free words. The main keywords used during the search process were "photogrammetry", "laser scanner", "optical scanner", "3D, and "face".

RESULTS

None of the included technologies significantly deviated from direct anthropometry. The obtained mean differences in the distances between the considered landmarks range from 1.10 to -1.74 mm.

CONCLUSION

Limiting the movements of the patient and scanner allows for more accurate facial scans with all the technologies involved. Active technologies such as laser scanners (LS), structured light (SL), and infrared structured light (ISL) have accuracy comparable to that of static stereophotogrammetry while being more cost-effective and less time-consuming.

Effect of Ambient Lights on the Accuracy of a 3-Dimensional Optical Scanner for Face Scans: An In Vitro Study

Most 3D scanners use optical technology that is impacted by lighting conditions, especially in triangulation with structured-light or laser techniques. However, the effect of ambient lights on the accuracy of the face scans remains unclear. The purpose of this study is to investigate the effect of ambient lights on the accuracy of the face scans obtained from the face scanner (EinScan Pro 2X Plus, Shining 3D Tech. Co., LTD., Hangzhou, China). A head model was designed in Rhinoceros 5 software (Rhino, Robert McNeel and Associates for Windows, Washington DC, USA) and printed with 200 micron resolution of polylactic acid and was dented with 2.0 mm of carbide bur to aid in superimposition in software. The head model was measured by a coordinate-measuring machine (CMM) to generate a reference stereolithography (STL) file as a control. The face model was scanned four times under nine light conditions: cool white (CW), warm white (WW), daylight (DL), natural light (NL), and illuminant (9w, 18w, 22w). Scan data were exported into an STL file. The scan STL files obtained were compared with the reference STL file by 3D inspection software (Geomagic Control X version 17, Geomagic, Morrisville, NC, USA). The deviations and root mean square errors (RMSEs) between the reference model (trueness) and within the group (precision) were selected for the statistical analysis. The statistical analysis was done using SPSS 20.0 (IBM Company, Chicago, USA). The trueness and precision were evaluated with the one-way ANOVA with multiple comparisons using the Tukey method. For trueness, the scanner showed the lowest RMSE under the NL group (77.18 ± 3.22) and the highest RMSE under the 18w-DL group (95.33 ± 6.89). There was a statistically significant difference between the NL group and the 18w-DL group (p < 0.05) for trueness. Similarly, for precision, the scanner showed the lowest RMSE under the NL group (56.92 ± 4.56) and the highest RMSE under the 9w-CW group (78.52 ± 10.61). There was statistically significant difference between NL, 18w-WW, 18w-CW, 18w-DL, 22w-WW, 22w-DL, 9w-CW, 9w-WW, and 9w-DL (p < 0.05) for the precision. Ambient lights affected the face scans. Under the natural light condition, the face scanner had the best accuracy in terms of both trueness and precision. The 18w-DL and 9w-WW conditions showed the least trueness whereasthe 9w-CW and 9w-DL conditions showed the least precision.

Facial Anthropometry and Analysis in Egyptian Women

Human facial analysis can be considered both an art and a science, and is used extensively to measure soft tissue proportions. Remarkable changes exist in anthropometric measures due to changes over centuries of geographical, genetic, and environmental factors, as well as waves of migration causing facial proportions to vary among the different ethnic groups. The purpose of this study was to establish facial soft tissue norms for the Egyptian female population between the ages of 18 and 50, as well as several age-related changes in facial measurements that are described fairly scarcely in the literature.

Asymmetry index for the photogrammetric assessment of facial asymmetry

INTRODUCTION

Facial asymmetry is common and can be clinically related to dental malocclusion, facial bone development, muscular imbalance, and soft tissues thickness, which should be assessed during diagnosis to choose proper treatment options. This study aimed to quantify the amount of symmetry/asymmetry in previously defined symmetrical and asymmetrical subjects, analyzing full-face 3-dimensional images.

METHODS

Seventy-six orthodontic patients' 3-dimensional face images were obtained with the 3dMD Trio-system (Atlanta, Ga) and processed with the Geomagic Control (64-bit; 3D Systems, Rock Hill, SC) software. Patients were divided into symmetrical and asymmetrical groups through a surface-based technique. Sixteen facial landmarks were positioned, an asymmetry index was calculated for each landmark, and an evaluation diagram of facial asymmetry was created through the asymmetry index mean and standard deviation of symmetrical and asymmetrical landmarks.

RESULTS

The asymmetry index mean varied from 0.05 to 1.51 in the symmetrical group and from 0.05 to 2.84 in the asymmetrical group. This study suggests that landmarks located in the lower third of the face have a greater asymmetry index than other landmarks.

CONCLUSIONS

The landmark-based technique does not exhibit statistically significant differences among asymmetrical and symmetrical patients for some landmarks. This approach provides useful information about the localization and the extension of asymmetry, in which bilateral landmarks showed a higher amount of asymmetry than median landmarks.

Reliability and Accuracy of 2D Photogrammetry: A Comparison With Direct Measurement

Objective

Facial anthropometric data is important for the design of respirators. Two-dimensional (2D) photogrammetry has replaced direct anthropometric method, but the reliability and accuracy of 2D photogrammetry has not been quantified. This study aimed to assess inter-rater reliability of 2D photogrammetry and to examine the reliability and accuracy of 2D photogrammetry with direct measurement.

Design

A cross-sectional study.

Setting

Malaysia.

Participants

A subset of 96 participants aged 18 and above.

Primary and secondary outcomes

Ten facial dimensions were measured using direct measurement and 2D photogrammetry. An assessment of inter-rater reliability was performed using intra-class correlation (ICC) of the 2D images. In addition, ICC and Bland-Altman analyses were used to assess the reliability and agreement of 2D photogrammetry with direct measurement.

Results

Except for head breadth and bigonial breadth, which were also found to have low inter-rater reliability, there was no significant difference in the inter-rater mean value of the 2D photogrammetry. The mean measurements derived from direct measurement and 2D photogrammetry were mostly similar. However, statistical differences were noted for two facial dimensions, i.e., bizygomatic breadth and bigonial breadth, and clinically the magnitude of difference was also significant. There were no statistical differences in respect to the remaining eight facial dimensions, where the smallest mean difference was 0.3 mm and biggest mean difference was 1.0 mm. The ICC showed head breadth had poor reliability, whilst Bland-Altman analyses showed seven out of 10 facial dimensions using 2D photogrammetry were accurate, as compared to direct measurement.

Conclusion

Only certain facial measurements can be reliably and accurately measured using 2D photogrammetry, thus it is important to conduct a reliability and validation study before the use of any measurement methods in anthropometric studies. The results of this study also suggest that 2D photogrammetry can be used to supplement direct measurement for certain facial dimensions.

Analysis of Lower Facial Third and Dental Proportions to Predict Maxillary Anterior Teeth Width in the Pakistani Population

Obtaining the size of the maxillary anterior teeth when performing an esthetic smile rehabilitation can be a difficult task. Metrics based on dental proportions to assist in the process are required. This study aimed to evaluate the lower facial third proportions i.e., the interalar, interphiltral, and intercommisural distance with dental proportions in predicting maxillary anterior teeth width in Pakistani citizens. This analytical study was conducted on 230 participants. Front face and retracted smile photographs were captured for all the participants, followed by maxillary impression making. The cast was then converted to 3D models for analysis. The data were entered into SPSS-25. Descriptive statistics were carried out for frequency, mean, standard deviation, and percentage calculation of gender, teeth widths, horizontal mid facial proportions, and age of the participants. Independent t-test was applied for analysis of gender and arch side disparity. Regression analyses were performed to analyze the relationship between independent variables (gender, age, weight, and height) and dependent variables (horizontal facial proportion, dental proportion). A p-value of ≤0.05 was considered statistically significant. The interphiltral distance (IPLD) modified with Preston proportion (PRP) showed no significant difference with combined central incisor width, whereas a significant difference was found with golden proportion (GP), 70% recurrent esthetic dental (RED) proportion, and golden percentage (GM) modification. However, the interalar (IAD) and intercommisural distance (ICoD) modified with dental proportions showed a significant difference with maxillary anterior teeth width. The width of maxillary anterior teeth determined by plaster dental cast and 3D dental cast showed no significant difference. The ICoD, IAD, and IPLD could not be used to determine combined central incisor and intercanine width directly. The interphiltral distance modified with Preston proportion is a reliable method to predict combined central incisor width in the population studied. There was a significant difference in gender disparity when ICD, IAD, and IPLD were modified with dental proportions, except in the case of IPLD by the Preston proportion group. The golden proportion, 70% RED proportion, and golden percentage by lower facial third facial proportions are not reliable methods to predict maxillary anterior teeth width.

Follow-up of extensive calcified costal cartilage-based rhinoplasty in Chinese People

OBJECTIVE

To the best of our knowledge, there is currently no such study in the area of extensive calcified costal cartilage rhinoplasty. The study evaluated patients' satisfaction with extensive calcified costal cartilage compared with no calcified costal cartilage.

METHOD

Thirty-five patients with extensive calcified costal cartilage underwent rhinoplasty at our institution between January 2018 and May 2020. We also used a control group of 35 patients with absent rib cartilage calcification to compare the outcomes. Satisfaction was evaluated by the photogrammetric measurements and Rhinoplasty Outcomes Evaluation (ROE) scale.

RESULTS

We found no significant difference in the nose measurement between the two groups before and after the operation. Besides, both groups had a significant difference in comparison with preoperative after surgery except for the nasofrontal angle. The difference between preoperative and postoperative ROE scores was statistically significant in both groups. We also compared the satisfaction of preoperative and postoperative outcomes between the two groups, where no difference was found between them. Each group had a patient who occurred an infection after surgery.

CONCLUSION

Autologous costal cartilage provides the most abundant source for graft fabrication. Patients with extensive calcified cartilage could undergo rhinoplasty and have satisfactory results instead of choosing an artificial implant.

Investigating the Reliability of Novel Nasal Anthropometry Using Advanced Three-Dimensional Digital Stereophotogrammetry

Three-dimensional surface imaging systems (3DSI) provide an effective and applicable approach for the quantification of facial morphology. Several researchers have implemented 3D techniques for nasal anthropometry; however, they only included limited classic nasal facial landmarks and parameters. In our clinical routines, we have identified a considerable number of novel facial landmarks and nasal anthropometric parameters, which could be of great benefit to personalized rhinoplasty. Our aim is to verify their reliability, thus laying the foundation for the comprehensive application of 3DSI in personalized rhinoplasty. We determined 46 facial landmarks and 57 anthropometric parameters. A total of 110 volunteers were recruited, and the intra-assessor, inter-assessor, and intra-method reliability of nasal anthropometry were assessed through 3DSI. Our results displayed the high intra-assessor reliability of MAD (0.012-0.29, 0.003-0.758 mm), REM (0.008-1.958%), TEM (0-0.06), rTEM (0.001-0.155%), and ICC (0.77-0.995); inter-assessor reliability of 0.216-1.476, 0.003-2.013 mm; 0.01-7.552%, 0-0.161, and 0.001-1.481%, 0.732-0.985, respectively; and intra-method reliability of 0.006-0.598°, 0-0.379 mm; 0 0.984%, 0-0.047, and 0-0.078%, 0.996-0.998, respectively. This study provides conclusive evidence for the high reliability of novel facial landmarks and anthropometric parameters for comprehensive nasal measurements using the 3DSI system. Considering this, the proposed landmarks and parameters could be widely used for digital planning and evaluation in personalized rhinoplasty, otorhinolaryngology, and oral and maxillofacial surgery.

Improved lip esthetics in patients with skeletal Class III malocclusion and facial asymmetry after isolated mandibular orthognathic surgery

INTRODUCTION

Asymmetry of the lips severely affects facial esthetics and is often one of the chief complaints of orthognathic patients, especially those with Class III malocclusion. The objectives of this study were to investigate the changes in lip symmetry in patients with mandibular prognathism and deviation and the relationships between jaw hard tissue and lip soft-tissue changes.

METHODS

Three-dimensional facial scan and cone-beam computed tomography scan data of 30 orthodontic-orthognathic patients treated with bilateral sagittal split ramus osteotomy were combined to conduct the research. Paired-sample t test and Pearson correlation coefficient were applied to compare the differences in the same variable before and after the orthognathic surgery and the potential correlations between the changes in hard and soft variables. To explore the important hard tissue variables influencing the lip soft-tissue changes, linear regression analysis was performed.

RESULTS

Although there was significant upper lip asymmetry presurgery, the upper lip asymmetry was corrected postsurgery. Surgical correction of the mandibular deviation was also accompanied by lengthening of the bilateral philtrum crests. Improvement in lip asymmetry and lengthening of the philtrum crests were primarily related to the transverse correction of the mandible rather than sagittal changes. The corresponding prediction formulas were established.

CONCLUSIONS

The isolated mandibular bilateral sagittal split ramus osteotomy surgery can substantially improve the upper and lower lip asymmetry in patients with mandibular prognathism and deviation, but one should be wary of the unesthetic effects associated with lengthening of the philtrum crests.

Chairside virtual patient protocol. Part 1: Free vs Guided face scan protocol

OBJECTIVES

The 3D facial scan technology allows to virtualize the face of the patient, that can be incorporated with other 3D dental images produced by digital scanning of the dental structures. Aim of this study is to investigate the trueness and precision of a low-cost portable face scanner, with two different scan techniques MATERIALS AND METHODS: Ten patients were enrolled for this study and seventeen soft tissue landmarks were selected to perform linear facial measurements, specifically Reference (Ref), Pronasion (Prn), Subnasal (Sn), Exocanthion Left (Ex-L), Exocanthion Right (Ex-R), Pogonion (Pg), Glabella (G), Alar curvature Right (Al-R), Alar curvature Left (Al-L), Zygion Left (Zn-L), Zygion Right (Zn-R), Orbital Left (Or-L), Orbital Right (Or-R), Tragus Right (T-R), Tragus Left (T-L), Chelion Right (Ch-R) and Chelion Left (Ch-L). Interlandmark distances were measured both manually and digitally. For the manual group ten measurements were made using a digital caliper. For digital group measurements were recorded on the patient face scan obtained using an Ipad Pro 3rd Gen. (Apple Store, Cupertino, CA, USA) and Bellus3D Dental Pro-App (Bellus3D, Inc. Campbell, CA, USA) using "face mode" scan with two different scanning techniques, named Free technique (FT) and Slider Technique (ST). Ten measurements were made for each technique. An open-source software (Meshlab; Meshlab) was used to record all the distances. A paired t-test was used to analyze FT and ST results. In order to further evaluate precision and scan repeatability a surface analysis was performed with both scanning techniques using a CAD software (GOM inspect, GOM) and the total differences in absolute 3D deviations were calculated as root mean square.

RESULTS

The comparison between manual and digital measurements showed a mean absolute difference of 0.95±0.25 for FT and 1.00±0.29 for the ST. Trueness analysis showed statistically significant differences for the Exocanthion L- Exocanthion R measurement with FT having better performance (P<.05). Precision analysis showed statistically significant differences for G-Pg, Ref-Zn-R and Prn-Zn-R with ST having better performance (P<.05). To achieve all the scans required without any signs of deformation, 184 scans were performed using Free technique and 124 scans using Slider technique. Surface analysis revealed a mean distance of 0.12±0.45 between Free scans and 0.13±0.46 between Slider scans in accordance with the linear measurement analysis CONCLUSION: The study showed that accuracy of low-cost portable scanner can be suitable for clinical use. The use of ST is suggested for a reliable clinical use due to the better precision and an effective reduction of motion artifacts and the lower compliance required to the patients during the scan.

Type of mandibular asymmetry affects changes and outcomes of bimaxillary surgery for class III asymmetry

OBJECTIVES

Various methods have been used to classify class III asymmetry. There is little information on the use of an asymmetry index to examine soft tissue changes and outcomes for patients with class III asymmetry. This study aimed to (1) evaluate soft tissue changes and outcomes for three types of mandibular asymmetry and (2) determine if measures are associated with type of asymmetry.

MATERIALS AND METHODS

Adults who consecutively underwent bimaxillary surgery using surgery-first approach for correction of class III asymmetry were divided into three groups based on type of mandibular asymmetry. This previously reported classification system is simple and mutually independent, categorizing mandibular asymmetry according to the amount and direction of ramus asymmetry relative to menton deviation: patients with a larger transverse ramus distance on the menton deviation side were divided into group 1 and group 2; group 1 (n = 45) exhibited a menton deviation larger than ramus discrepancy; group 2 (n = 11) exhibited a menton deviation less than ramus discrepancy; group 3 (n = 22) had larger transverse ramus distance contralateral to the side of the menton deviation. Soft tissue facial asymmetry indices, calculated from cone beam computed tomography images, assessed midline and contour asymmetry presurgery, changes postsurgery, and outcomes.

RESULTS

Compared with groups 1 and 2, the presurgery index for contour and midline asymmetry was smallest for group 3. All the three groups had significant improvement in midline asymmetry postsurgery, and outcome measures were good; there were no differences between groups. However, contour asymmetry only improved significantly for groups 1 and 2. The outcome for contour asymmetry was fair for groups 1 and 3 and poor for group 2.

CONCLUSIONS

Bimaxillary surgery significantly improved facial midline asymmetry. The type of mandibular asymmetry was associated with postsurgical changes and outcomes for contour asymmetry.

CLINICAL RELEVANCE

Understanding the types of mandibular asymmetry could help clinicians to develop treatment plans and predict treatment changes and outcomes.

Testing the reliability of CT scan-based dental wear magnitude scoring

OBJECTIVES

Digital models are now frequently used in biological anthropology (bioanthropology) research. Despite several studies validating this type of research, none has examined if the assessment of dental wear magnitude based on Computerized Tomography (CT) scans is reliable. Thus, this study aims to fill this gap and assess if dental wear magnitude scoring based on CT scans provides results consistent with scoring based on direct observation of the physical specimens.

MATERIALS AND METHODS

Dental wear magnitude from 412 teeth of 35 mandibles originating from the Portuguese Muge and Sado Mesolithic shell-middens was scored. The mandibles were also CT scanned and visualized using 3D Slicer. CT scan-based scoring of dental wear magnitude was then undertaken. Two scoring rounds were undertaken for each observation method (totaling four scoring rounds) and an intra-observer error test was performed. The averaged results of the two observation methods were compared via boxplots with paired cases.

RESULTS

Intra-observer error was negligible and non-significant. Scoring results are comparable between the two observation methods. Notwithstanding, some differences were found, in which CT scan assessment generally overestimates dental wear when compared to direct observation.

DISCUSSION

Our results generally validate the use of CT scans in studies of dental wear magnitude. Notwithstanding several caveats relating to CT scanning and visualization limitations should be considered to avoid over or under-estimation of dental wear.

Tooth-borne versus tooth-bone-borne rapid maxillary expanders according to a stereophotogrammetric evaluation of facial soft tissues: A randomized clinical trial

OBJECTIVES

To evaluate the effects of tooth-borne and tooth-bone-borne rapid maxillary expansion (RME) on soft tissue with stereophotogrammetry.

SETTING AND SAMPLE POPULATION

Thirty two patients (15 males and 17 females) who met inclusion criteria were divided into two groups. In the first group, tooth-borne RME appliance (hyrax) was applied to 16 patients (9 males and 7 females mean age 13.4 ± 1.3 years), and in the second group, tooth-bone-borne RME appliance (hybrid hyrax) was applied to 16 patients (6 males and 10 females, mean age 13.05 ± 1.24 years).

MATERIALS AND METHODS

Changes in soft tissues before RME (T0) and post-retention (T1) period were evaluated by stereophotogrammetry. Linear and angular measurements were performed. Independent- and dependent-sample t tests were used to compare intra- and inter-group differences at P < .05 significance level.

RESULTS

The data revealed statistically significant changes in nasal width, mid-face width, upper lip vermillion length/lower lip vermillion length ratio and upper lip angle in hyrax group. (P < .05) Also nasal width, lower lip length, lower lip vermillion length, anterior face height, lower face height, convexity angle and mandibular angle showed statistically significant changes in hybrid hyrax group. (P < .05) In the inter-group evaluation, no significant differences were found except upper lip and mandible angle. (P < .05).

CONCLUSION

Both hyrax and hybrid hyrax expanders had effects on soft tissue profile. Anterior face height and lower face height increased in both groups. Upper lip length increased by 0.36 mm in the hybrid group and 0.10 mm in the hyrax group.

TRIAL REGISTRATION

This trial was registered at Clinicaltrials.gov (Identifier: NCT04828213).

Scientific validation of three-dimensional stereophotogrammetry compared to the IGAIS clinical scale for assessing wrinkles and scars after laser treatment

Measuring outcomes from treatments to the skin is either reliant upon patient’s subjective feedback or scale-based peer assessments. Three-Dimensional stereophotogrammetry intend to accurately quantify skin microtopography before and after treatments. The objective of this study is comparing the accuracy of stereophotogrammetry with a scale-based peer evaluation in assessing topographical changes to skin surface following laser treatment. A 3D stereophotogrammetry system photographed skin surface of 48 patients with facial wrinkles or scars before and three months after laser resurfacing, followed immediately by topical application of vitamin C. The software measured changes in skin roughness, wrinkle depth and scar volume. Images were presented to three observers, each independently scoring cutaneous improvement according to Investigator Global Aesthetic Improvement Scale (IGAIS). As for the results, a trend reflecting skin/scar improvement was reported by 3D SPM measurements and raters. The percentage of topographical change given by the raters matched 3D SPM findings. Agreement was highest when observers analysed 3D images. However, observers overestimated skin improvement in a nontreatment control whilst 3D SPM was precise in detecting absence of intervention. This study confirmed a direct correlation between the IGAIS clinical scale and 3D SPM and confirmed the efficacy and accuracy of the latter when assessing cutaneous microtopography alterations as a response to laser treatment.

Three-dimensional objective evaluation of facial palsy and follow-up of recovery with a handheld scanner

BACKGROUND

Clinicians need accurate, reproducible, fast, and cost-effective grading systems to determine facial functions. There is currently no internationally accepted objective method to report the loss of function at the onset of facial paralysis and subsequent recovery. Our study aimed to test a three-dimensional handheld light scanner's efficacy for grading facial paralysis and monitoring recovery.

METHODS

Sixty-one healthy volunteers (28 men and 33 women) aged between 20 and 75 years (mean 36.4 ± 11.9 years old) and 22 patients with facial palsy (10 male and 12 female patients) aged between 12 and 77 years (mean 47.6 ± 19.7 years old) were included in the study. The healthy individuals' and patients' facial scans were performed with a three-dimensional handheld scanner during different facial expressions at 3-month intervals. The asymmetry and intensity degree of each facial expression were determined in terms of the root mean square.

RESULTS

After facial paralysis, a significant larger asymmetry value (1.2 ± 0.4 mm vs. 2.0 ± 0.8 mm and p<0.05) was determined as compared to the control group, while a significant smaller intensity value (2.3 ± 1.2 mm vs. 1.7 ± 0.9 mm and p<0.05) was observed. At the end of 3 months, both parameters showed a tendency to recover.

CONCLUSION

Our findings suggest that three-dimensional morphological analyses may be an effective method to grade facial palsy. However, our data need to be confirmed by larger cohort size and more extended follow-up periods.

Quantitating the art and science of esthetic clinical success

BACKGROUND

Beginning with the biobehavioral bases of esthetic experiences, this article presents a quantitative analytic review of the motives and methods of providers and consumers of orthodontic treatment.

METHOD

A primary focus is determining the anthropometric bases of self and others' perceived preference and satisfaction with changes in facial appearance. These quantitative analyses have been based on determining the frequency and magnitude of reliability and validity measures of diagnosis, treatment, and satisfaction outcome. Socioeconomic considerations are also quantitated regarding the discrepancy between objective need for treatment as determined for example by the Index of Orthodontic Treatment Need and the subjective demand for treatment.

RESULTS

The major contribution of this article is the quantitation of the components of esthetic experience from sensation of perception using psycho physical methods, such as Perceptometrics, for determining the morphological basis of perceived facial attractiveness adjusted for ethnocultural differences updated by 3-dimensional and artificial intelligence technology. Recent quantitation of smile components has also added to the measures of esthetically successful treatment. Further contribution of orthodontists to mental and physical health is demonstrated by the differences between perceived personality attributes in profile and full-frontal views of symmetric and asymmetric faces. Such information can facilitate the clinician's ability to determine the ideational representation of the patients' perceived pre- and post-treatment outcome.

CONCLUSION

The quantitative analysis of the motives and methods involved in the orthodontic treatment process has been combined with the neurophysiological correlates of producing and observing/evaluation of the esthetic experiences of both patients and orthodontists/dentists.

Three-Dimensional Facial Scanning at the Fingertips of Patients and Surgeons: Accuracy and Precision Testing of iPhone X Three-Dimensional Scanner

BACKGROUND

The iPhone X (Apple, Inc., Cupertino, Calif.) is the first smartphone to be released with a high-fidelity three-dimensional scanner. At present, half of all U.S. smartphone users use an iPhone. Recent data suggest that the majority of these 230 million individuals will upgrade to the iPhone X within 2 years. This represents a profound expansion in access to three-dimensional scanning technology, not only for plastic surgeons but for their patients as well. The purpose of this study was to compare the iPhone X scanner against a popular, portable three-dimensional camera used in plastic surgery (Canfield Vectra H1; Canfield Scientific, Inc., Parsippany, N.J.).

METHODS

Sixteen human subjects underwent three-dimensional facial capture with the iPhone X and Canfield Vectra H1. Results were compared using color map analysis and surface distances between key anatomical landmarks. To assess repeatability and precision of the iPhone X three-dimensional scanner, six facial scans of a single participant were obtained and compared using color map analysis. In addition, three-dimensionally-printed facial masks (n = 3) were captured with each device and compared.

RESULTS

For the experiments, average root mean square was 0.44 mm following color map analysis and 0.46 mm for surface distance between anatomical landmarks. For repeatability and precision testing, average root mean square difference following color map analysis was 0.35 mm. For the three-dimensionally-printed facial mask comparison, average root mean square difference was 0.28 mm.

CONCLUSIONS

The iPhone X offers three-dimensional scanning that is accurate and precise to within 0.5 mm when compared to a commonly used, validated, and expensive three-dimensional camera. This represents a significant reduction in the barrier to access to three-dimensional scanning technology for both patients and surgeons.

Three-dimensional surface scanning methods in osteology: A topographical and geometric morphometric comparison

Objectives

Three‐dimensional (3D) data collected by structured light scanners, photogrammetry, and computed tomography (CT) scans are increasingly combined in joint analyses, even though the scanning techniques and reconstruction software differ considerably. The aim of the present study was to compare the quality and accuracy of surface models and landmark data obtained from modern clinical CT scanning, 3D structured light scanner, photogrammetry, and MicroScribe digitizer.

Material and methods

We tested 13 different photogrammetric software tools and compared surface models obtained by different methods for four articulated human pelves in a topographical analysis. We also measured a set of 219 landmarks and semilandmarks twice on every surface as well as directly on the dry bones with a MicroScribe digitizer.

Results

Only one photogrammetric software package yielded surface models of the complete pelves that could be used for further analysis. Despite the complex pelvic anatomy, all three methods (CT scanning, 3D structured light scanning, photogrammetry) yielded similar surface representations with average deviations among the surface models between 100 and 200 μm. A geometric morphometric analysis of the measured landmarks showed that the different scanning methods yielded similar shape variables, but data acquisition via MicroScribe digitizer was most prone to error.

Discussion

We demonstrated that three‐dimensional models obtained by different methods can be combined in a single analysis. Photogrammetry proved to be a cheap, quick, and accurate method to generate 3D surface models at useful resolutions, but photogrammetry software packages differ enormously in quality.

Morphological Analysis of Nose in Patients of Tessier No. 0 Cleft With a Bifid Nose in China

Objective: Facial cleft involves complex malformations. No study assessed the facial deformity of Tessier No. 0 cleft with a bifid nose. Thus, we used anthropometric measurements to access the nose in patients. Methods: A total of 24 bifid nose deformities underwent surgery at our institution between 2010 and 2019. Standardized photographs were taken preoperatively and postoperatively. Landmarks were identified on these images; measurements for nasal analysis were performed and compared with the established Chinese norms. Surgical method differences were also analyzed. Results: The median follow-up time was 2.51 years. Postoperatively, there is a significant difference in comparison with preoperative in the nasal index, medial canthus and nose width index, nasolabial angle, nasofacial angle, ala length and nasal bridge length index, nasal tip protrusion and nasal width index, and nasal width and ala length index. Furthermore, the medial canthus and nose width index, and nasal width and ala length index were significantly larger in ordinary people, while ala length and nasal bridge length index and nasal tip protrusion and nasal width index were smaller. After surgery, most angles and index were standard except the nasolabial angle in the females, and ala length and nasal bridge length index in the males. Moreover, as for the group of costal cartilage transplantation, most index and angles have improved after surgery including nasolabial angle, nasofacial angle, ala length and nasal bridge length index, nasal tip protrusion and nasal width index, and nasal width and ala length index. However, only nasal tip protrusion and nasal width index, columella length and nasal tip protrusion index, and nasal width and ala length index in the silicone prosthesis group implantation has significance. Costal cartilage transplantation can also better improve ala length and nasal bridge length index than the silicone prosthesis implantation. Conclusion: Most defects can be repaired with surgery, but the outcome has a lack of evaluation. Thus, anthropometric assessment can serve as a material for nasal and reconstructive surgery.

[Comparison of the registration methods for the three-dimensional facial scans applied to the design of full-arch implant supported restoration]

OBJECTIVE

To compare the registration accuracy of three-dimensional (3D) facial scans for the design of full-arch implant supported restoration by five methods and to explore the suitable registration method.

METHODS

According to the criteria, ten patients with maxillary edentulous jaw or end-stage dentition requiring implant supported restorations were enrolled in this study. A special rim with individual feature marks reflected appropriate occlusal relationship and esthetic characteristics was made for each patient. Both 3D facial scan data of natural laughter and with opener traction to expose the teeth or occlusal rim of each patient were acquired by facial scan and input to the digital analysis software Geomagic Qualify 2012. The dataset was superimposed by five different methods: seven facial anatomical landmark points alignment, facial immobile area alignment (forehead and nasal area), facial anatomical landmark points and immobile area combining alignment, facial feature points alignment, facial and intraoral feature points alignment with the same local coordinate system. The three-dimensional deviation of the same selected area was calculated, the smaller the deviation, the higher the registration accuracy. The 3D deviation was compared among the three registration methods of facial anatomical landmark points, facial immobile area alignment and the combination of the above two methods. Friedman test was performed to analyze the difference among the three methods (α=0.05). The effect of the aid of the facial and intraoral feature points were evaluated. Paired t test were performed to analyze the difference (P<0.05).

RESULTS

The average three-dimensional deviation of the selected area after alignment with the facial anatomical landmarks was (1.501 2±0.406 1) mm, significantly larger than that of the facial immobile area best-fit alignment [(0.629 1±0.150 6) mm] and the combination of the two methods[(0.629 1±0.150 6) mm] (P < 0.001). The aid of the facial feature points could significantly reduce the deviation (t=1.001 3, P < 0.001). There was no significant statistical difference in the remaining groups.

CONCLUSION

The forehead area of the 3D facial scan can be exposed as much as possible. The establishment of facial characteristic landmark points and the use of the invariant area alignment can improve the accuracy of registration. It should be clinically feasible to apply three-dimensional facial scan to the design of full-arch implant supported restoration with the registration of the immobile area on the face especially the forehead area.

Three-dimensional anthropometric analysis of eyelid aging among Chinese women

BACKGROUND

Eyelid morphology is highly susceptible to aging. Previous studies have described the process of eyelid aging in Caucasians; however, anthropometric data describing aging in Chinese eyelids are lacking. Therefore, this study aimed to quantitatively analyze the effect of aging on the eyelids of Chinese women through a three-dimensional (3D) anthropometry.

METHODS

In this prospective, cross-sectional study, 3D photos were captured from 188 healthy Chinese Han women, who were categorized into four age groups. Anthropometric landmarks were identified for the measurement of eyelid parameters, and a unified coordinate system was built into each subject. Linear and angular measurements were computed from the coordinates and were compared between the groups.

RESULTS

An age-related decrease was observed in the ocular width, outer canthal width, palpebral fissure height, and multiple angular measurements. This indicated upper eyelid ptosis, which reduced the lateral and superior visual field. Lateral shift of the upper eyelid arc was not observed. The lower eyelid underwent slight elevation with increasing age. Aging rendered the periorbital region esthetically less pleasing, as shown by changes in the multiple proportion indices computed. Furthermore, an intergroup comparison indicated that eyelid aging was accelerated after the age of 40 years among Chinese women.

CONCLUSION

This study used 3D photography to quantitatively analyze how eyelids in Chinese women changed with age. The anthropometric data collected could help with antiaging cosmetic surgery planning and postoperative assessment.

Reliability and Agreement of 3D Anthropometric Measurements in Facial Palsy Patients Using a Low-Cost 4D Imaging System

The reliability (precision) and agreement (accuracy) of anthropometric measurements based on manually placed 3D landmarks using the RealSense D415 were investigated in this paper. Thirty facial palsy patients, with their face in neutral (resting) position, were recorded simultaneously with the RealSense and a professional 3dMD imaging system. First the RealSense depth accuracy was determined. Subsequently, two observers placed 14 facial landmarks on the 3dMD and RealSense image, assessing the distance between landmark placement. The respective intra- and inter-rater Euclidean distance between the landmark placements was 0.84 mm (±0.58) and 1.00 mm (±0.70) for the 3dMD landmarks and 1.32 mm (±1.27) and 1.62 mm (±1.42) for the RealSense landmarks. From these landmarks 14 anthropometric measurements were derived. The intra- and inter-rater measurements had an overall reliability of 0.95 (0.87 - 0.98) and 0.93 (0.85 - 0.97) for the 3dMD measurements, and 0.83 (0.70 - 0.91) and 0.80 (0.64 - 0.89) for the RealSense measurements, respectively, expressed as the intra-class correlation coefficient. Determined by the Bland-Altman analysis, the agreement between the RealSense measurements and 3dMD measurements was on average -0.90 mm (-4.04 - 2.24) and -0.89 mm (-4.65 - 2.86) for intra- and inter-rater agreement, respectively. Based on the reported reliability and agreement of the RealSense measurements, the RealSense D415 can be considered as a viable option to perform objective 3D anthropomorphic measurements on the face in a neutral position, where a low-cost and portable camera is required.

Evaluating the accuracy of hand models obtained from two 3D scanning techniques

The aim of this study was to identify an efficient approach for 3D imaging of hand. The 3D photographs of hand were taken with Gemini structured-light scanning system (SL scanning) and CT scanning. The 3D photographs, average time of scanning and reconstruction were compared between these two indirect techniques. The reliability, reproducibility and accuracy were evaluated in these two indirect techniques and the direct measurement (DM). Statistical differences in the measurements were assessed by 99% probability, with clinical significance at > 0.5 mm. The Gemini structured-light scanning system established a complete and smooth 3D hand photograph with shorter scanning and reconstruction time. Reproducibility of CT scanning and SL scanning methods was better (P < 0.01, both) than the DM, but did not differ significantly from each other (P = 0.462). Of the 19 (31.58%) measurements obtained, 6 showed significant differences (P < 0.01). Significant differences were observed more often for circumference dimensions (5/9, 55.56%) than for length dimensions (1/10, 10%). Mean absolute error (AE) of the 10 subjects was very low for 3D CT (0.29 ± 0.10 mm) and SL scanning (0.30 ± 0.11 mm). Absolute percentage error (APE) was 4.69 ± 2.33% and 4.88 ± 2.22% for 3D CT and SL scanning, respectively. AE for the PIP circumference between the 3rd finger (0.58 mm) and 4th finger (0.53 mm) scan was > 0.5 mm, indicating significant difference between DM and CT scanning at the level of 99% probability. In this study, the Gemini structured-light scanning system not only successfully established a complete and smooth 3D hand photograph, but also shortened the scanning and reconstruction time. Compared to the DM, measurements obtained using the two indirect techniques did not show any statistically or clinically insignificant difference in the values of the remaining 17 of 19 measurements (89.47%). Therefore, either of the two alternative techniques could be used instead of the direct measurement method.

Stereophotogrammetry to reveal age-related changes of labial morphology among Chinese women aging from 20 to 60

Background

The lip is of important aesthetic value and highly subjected to aging. Collecting anthropometric baseline data and understanding age‐related changes of labial morphology can help with diagnosis of deformity, assessment of aging, and planning of cosmetic procedures. Many studies have focused on Caucasians, while there is a lack of anthropometric data on Chinese women.

Methods

A total of 169 women were enrolled in this cross‐sectional study and divided into four consecutive age groups. Linear distances, angles, and surface area data were obtained via stereophotogrammetry. Intergroup comparisons between different age groups were performed to find age‐related differences.

Results

Lip width significantly increased with age while philtrum width seemed to show no obvious change. Cutaneous upper and lower lip height increased, lengthening the lip in the vertical dimension. Decrease of upper vermilion height and changes in angles indicated that aging process shortened the upper vermilion and flattened the vermilion border. Surface area also showed age‐related changes. Intergroup comparison showed no statistical significance in most variables between 20s and 30s or 30s and 40s, while age‐related changes in some variables were significant between 40s and 50s.

Conclusion

This study provided anthropometric data of labial morphology across a wide age range. Aging process affected a variety of labial anthropometric variables. Age‐related changes accelerated after 40 among Chinese women.

Sources of variation in the 3dMDface and Vectra H1 3D facial imaging systems

As technology advances and collaborations grow, our ability to finely quantify and explore morphological variation in 3D structures can enable important discoveries and insights into clinical, evolutionary, and genetic questions. However, it is critical to explore and understand the relative contribution of potential sources of error to the structures under study. In this study, we isolated the level of error in 3D facial images attributable to four sources, using the 3dMDface and Vectra H1 camera systems. When the two camera systems are used separately to image human participants, this analysis finds an upper bound of error potentially introduced by the use of the 3dMDface or Vectra H1 camera systems, in conjunction with the MeshMonk registration toolbox, at 0.44 mm and 0.40 mm, respectively. For studies using both camera systems, this upper bound increases to 0.85 mm, on average, and there are systematic differences in the representation of the eyelids, nostrils, and mouth by the two camera systems. Our results highlight the need for careful assessment of potential sources of error in 3D images, both in terms of magnitude and position, especially when dealing with very small measurements or performing many tests.

Perioral Ruler in Routine Esthetic Surgery: Convenient and Exact

Lip and perioral surgery, like any other esthetic surgery, requires an exact and convenient measurement tool to ensure reliable and reproducible outcomes. Although three-dimensional measuring equipment has proven its effectiveness in measuring facial parameters over the past two decades, it has some drawbacks, including high cost, long scanning times, and non-portability. Thus, digital photography remains the standard tool of measurement in esthetic surgery to date. Many authors have presented evaluation and measurement methods using digital photography in combination with different tools. However, there are no specific tools for the perioral region. Therefore, we devised a specific ruler for perioral measurements. The ruler has differently colored lines for length and angle measurements and a reference point for correct positioning. It can be used in preoperative consultation, intraoperative orientation, and postoperative evaluation.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.

Reliability of optical devices for three-dimensional facial anatomy description: a systematic review and meta-analysis

The use of three-dimensional (3D) optical instruments to measure soft tissue facial characteristics is increasing, but systematic assessments of their reliability, practical use in research and clinics, outcome measurements, and advantages and limitations are not fully established. Therefore, a review of the current literature was performed on the reliability of facial anthropometric measurements obtained by 3D optical facial reproductions as compared to conventional anthropometry or other optical devices. The systematic literature search was conducted in electronic databases following the PRISMA guidelines (PROSPERO registration: CRD42018085473). Overall, 815 studies were identified, with 27 final papers included. Two meta-analyses were conducted. Tested devices included conventional cameras, laser scanning, stereophotogrammetry, and structured light. Studies measured living people or inanimate objects. Overall, the optical devices were considered reliable for the measurement of linear distances. Some caution is needed for surface assessments. All instruments are suitable for the analysis of inanimate objects, but fast scan devices should be preferred for living subjects to avoid motion artefacts in the orbital and nasolabial areas. Prior facial landmarking is suggested to improve measurement accuracy. Practical needs and economic means should direct the choice of the most appropriate instrument. Considering the increasing interest in surface-to-surface measurements, fast scan devices should be preferred, and dedicated protocols devised.

Validity and reproducibility of the 3D VECTRA photogrammetric surface imaging system for the maxillofacial anthropometric measurement on cleft patients

OBJECTIVES

To validate the accuracy and reproducibility of linear measurements of three-dimensional (3D) images and to compare the measurements with the direct anthropometry method on cleft lip and palate (CLP) patients.

MATERIALS AND METHODS

Nineteen linear facial measurements were derived from 16 standardized surface landmarks obtained from 37 cleft patients (20 males, 17 females; mean age 23.84 years, standard deviation ± 6.02). They were taken manually with calipers and were compared with the digitally calculated distance on the 3D images captured using the VECTRA-M5 360° Imaging System with pre-marked landmarks. Another pair of 19 linear measurements were computed on the 3D images 2 weeks apart for intra- and inter-observer agreements. Statistical analyses used were paired t test, the Bland-Altman analysis, and the intra-class correlation coefficient (ICC) index.

RESULTS

Most of the linear measurements showed no statistically significant differences between the proposed method and direct anthropometry linear measurements. Nevertheless, bias of the 3D imaging system is present in the linear measurements of the nose width and the upper vermillion height. The measurements' mean biases were within 2 mm, but the 95% limit of agreement was more than 2 mm. Intra- and inter-observer measurements generally showed good reproducibility. Four inter-observer measurements, the upper and lower face heights, nose width, and pronasale to left alar base were clinically significant.

CONCLUSIONS

Measurements obtained from this 3D imaging system are valid and reproducible for evaluating CLP patients.

CLINICAL RELEVANCE

The system is suitable to be used in a clinical setting for cleft patients. However, training of the operator is strictly advisable.

A comparison between 2D and 3D methods of quantifying facial morphology

Objectives

Currently, two & three-dimensional (2D & 3D) imaging techniques have largely replaced the direct anthropometric method in the assessment of facial morphology, but the difference between the two techniques was not quantified. Therefore, the aim of this study was to compare and quantify (the difference between) the two techniques.

Materials and methods

The faces of 150 subjects (75 males, 75 females) of northern Nigeria, predominantly Hausa ethnic group, were photographed (using digital camera) and scanned (using a 3D surface laser scanner). Facial dimensions were generated from the resulting virtual 2D and 3D models. Data were analyzed using R-statistic software & Paired sample t-test/Pearson correlation were conducted to compare the two methods and to quantify the level of closeness between the two measurements.

Results

Intraclass correlation coefficient (ICC) was very low (0.26) for the 3D and 2D measurements indicating the level of differences between the methods. Measurements taken with laser scanner were higher relative to the one taken by camera. The mean differences between the 3D and the 2D methods of quantifying facial morphology indicated a statistically significant positive difference. CONCLUSION: 2D and 3D anthropometry cannot be used interchangeably since there exists statistically significant variation between the two methods.

Scan time, reliability and accuracy of craniofacial measurements using a 3D light scanner

Aim

To evaluate time, reliability and accuracy of craniofacial measurements with a 3D light scanner, considering prior demarcation of surface points on the face.

Materials and methods

Eleven facial measurements of 15 volunteers were obtained by a scanner (Artec Eva TM) and by a caliper directly on the face, with or without demarcation of facial reference points. Inter and intra-method comparison were examined by intraclass correlation coefficient and analysis of random error by the Dahlberg formula. Agreement between the methods was analyzed by the Bland-Altman. A Wilcoxon test was used to compare the time for each method, at p < 0.05.

Results

Marking points on the face improved accuracy for both methods. In the inter-methods analysis with landmarks, the scanner showed excellent reliability in all measures (ICC = 0.92-0.97, p < 0.0001). Measurements accuracy with scanner was around 2 mm when the points were not previously marked and about 1 mm when the points were marked. Measures taken with the scanner, however, took twice as long, compared with the direct method.

Conclusions

Craniofacial measurements obtained with scanner showed excellent reliability and accuracy, which qualifies this method for clinical and scientific use. Accuracy is improved when the points were previously marked on face. However, the time needed to obtain measurements is greater than about 4 min for the direct method.

Reliability of Measurements on Plaster and Digital Models of Patients with a Cleft Lip and Palate

Objective

The purpose of this study was to determine (1) the more and less reliable measurements/methods and (2) the influence of knowledge and skill on the inter-examiner, intra-examiner, and inter-method reliability of nasolabial measurements on plaster casts and three dimensional (3D) stereophotogrammetric images of casts in infants with an unrepaired unilateral cleft lip and palate (UUCLP).

Methods

Preoperative extraoral plaster casts from 42 patients with UUCLP were measured with a digital caliper, and the image acquisition of casts was performed with the 3dMDface stereophotogrammetry system (3dMD, Atlanta, GA). Two examiners (one postgraduate student, one lecturer) evaluated 19 nasolabial measurements in two separate sessions.

Results

Intra-rater, inter-rater, and inter-method reliability was lower in measurements of nasal, philtral, and nasal floor width. Almost all of the interclass correlation coefficients (ICC) for measurements performed by the lecturer were above 0.75, whereas the intra-examiner reliability of some measurements performed by the postgraduate student showed low ICC (<0.75).

Conclusion

Measurements of curving slopes, such as nasal width, of small dimensions, such as nostril floor width, and deformity-affected anatomic parts, such as philtrum width, presented a low reliability. Measurements on 3D images showed a higher reliability compared to plaster model measurements performed by the postgraduate student. Therefore, it may be recommended to use 3D digital images of infants with CLP for nasolabial measurements especially if performed in postgraduate settings.