Evaluation of the 3dMDface system as a tool for soft tissue analysis

Accuracy of Smartphone-Based Three-Dimensional Facial Scanning System: A Systematic Review

BACKGROUND

Recently, the integration of 3D face scanning into smartphones has raised vast interest in plastic surgery. With the release of smartphones featuring 3D face scanning technology, users now can capture detailed 3D models of their faces using their smartphones. However, trueness and precision of this system is less well established.

METHODS

PubMed, Cochrane Library, Embase, ScienceDirect, Scopus, and Web of Science databases were searched for studies evaluating 3D scanning of smartphone devices and conventional 3D imaging systems from January 1, 2017, to June 1, 2023. A qualitative systematic review was conducted by two review authors after independently selecting studies, extracting data, and assessing the risk of bias of included studies.

RESULTS

A total of 11 studies were included, all focusing on the accuracy of smartphone 3D facial scanning. The results show that although smartphones perform poorly on deep and irregular surfaces, they are accurate enough for clinical applications and have the advantage of being economical and portable.

CONCLUSIONS

Smartphone-based 3D facial scanning has been basically validated for clinical application, showing broad clinical application prospects in plastic surgery.

LEVEL OF EVIDENCE II

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 .

Comparison of methodologies for craniofacial soft-tissue cephalometrics: The value of virtual reality

BACKGROUND

Myriad options are available for plastic surgeons to perform soft-tissue analysis, which is vital to perioperative evaluation and research. Our objective is to compare the accuracy, precision, and efficiency of the available cephalometric modalities for conducting facial soft-tissue measurements.

METHODS

Twenty soft-tissue facial measurements were performed by 5 measurers with varying experiences on 5 adult subjects, using 6 methods-manual calipers, cone-beam CT, virtual reality (VR), 3D stereophotogrammetry, iPad-based 3D photogrammetry, and 2-dimensional photographs. Measurement sessions were timed and performed in triplicate, for a total of 9000 measurements. Intraclass correlation coefficient (ICC) was calculated for accuracy and one-way ANOVA was used for comparison. The coefficient of variation (CoV) was compared among groups to evaluate the precision of different methods by considering caliper measurements as the gold standard.

RESULTS

ICC among raters was 0.932, indicating excellent reliability. VR was significantly faster than other methods (137 s vs. 217 s for caliper, p < 0.001). CoV was the highest for 2D photographs and the lowest for VR (11.0 vs. 6.4, p < 0.001). The CoV of the caliper was similar to that of other methods, except for 2D photography, which was significantly higher. Measurements with the greatest absolute difference from caliper measurements, across modalities, were those around the eyes (left to right exocanthion), tragion to antitragion, and tragion to exocanthion.

CONCLUSION

2D photography is not an accurate method for cephalometric measurements. VR had the lowest variation between measurements, and was the fastest and equivalent to caliper measurements in accuracy. For studies involving a large number of cephalometrics, VR measurements may be a good option to improve study throughput.

Validation of three-dimensional facial imaging captured with smartphone-based photogrammetry application in comparison to stereophotogrammetry system

Statement of problem

The development of facial scanners has improved capabilities to create three-dimensional (3D) virtual patients for accurate facial and smile analysis. However, most of these scanners are expensive, stationary and involve a significant clinical footprint. The use of the Apple iPhone and its integrated "TrueDepth" near-infrared (NIR) scanner combined with an image processing application (app) offers the potential to capture and analyze the unique 3D nature of the face; the accuracy and reliability of which are yet to be established for use in clinical dentistry.

Purpose

This study was designed to validate both the trueness and precision of the iPhone 11 Pro smartphone TrueDepth NIR scanner in conjunction with the Bellus3D Face app in capturing 3D facial images in a sample of adult participants in comparison to the conventional 3dMDface stereophotogrammetry system.

Material and methods

Twenty-nine adult participants were prospectively recruited. Eighteen soft tissue landmarks were marked on each participant's face before imaging. 3D facial images were captured using a 3dMDface system and the Apple iPhone TrueDepth NIR scanner combined with the Bellus3D Face app respectively. The best fit of each experimental model to the 3dMD scan was analyzed using Geomagic Control X software. The root mean square (RMS) was used to measure the "trueness" as the absolute deviation of each TrueDepth scan from the reference 3dMD image. Individual facial landmark deviations were also assessed to evaluate the reliability in different craniofacial regions. The "precision" of the smartphone was tested by taking 10 consecutive scans of the same subject and comparing those to the reference scan. Intra-observer and inter-observer reliabilities were assessed using the intra-class correlation coefficient (ICC).

Results

Relative to the 3dMDface system, the mean RMS difference of the iPhone/Bellus3D app was 0.86 ± 0.31 mm. 97% of all the landmarks were within 2 mm of error compared with the reference data. The ICC for intra-observer reproducibility or precision of the iPhone/Bellus3D app was 0.96, which was classified as excellent. The ICC for inter-observer reliability was 0.84, which was classified as good.

Conclusions

These results suggest that 3D facial images acquired with this system, the iPhone TrueDepth NIR camera in conjunction with the Bellus3D Face app, are clinically accurate and reliable. Judicious use is advised in clinical situations that require high degrees of detail due to a lack of image resolution and a longer acquisition time. Generally, this system possesses the potential to serve as a practical alternative to conventional stereophotogrammetry systems for use in a clinical setting due to its accessibility and relative ease of use and further research is planned to appraise its updated clinical use.

Evaluation of facial soft tissue asymmetric changes in Class III patients after orthognathic surgery using three-dimensional stereophotogrammetry

The aim of this study was to investigate changes in facial soft tissue asymmetry over time after orthognathic surgery in Class III patients using three-dimensional stereophotogrammetry. The study included 101 patients with a skeletal Class III malocclusion (72 female, 29 male; age range 19-53 years, mean age 28.6 years) who underwent orthognathic surgery. The minimum follow-up was 12 months. Three-dimensional photographs were acquired using the 3dMDtrio stereophotogrammetry system, and 21 anthropometric landmark positions were evaluated at three time points: before surgery (T0), 6 months (T1) and 12 months (T2) after surgery. Facial asymmetry was assessed and classified as follows: 0-2 mm, mild; 2-5 mm, moderate;> 5 mm, severe. The average distance for whole face asymmetry differed between T0 (median 0.76 mm) and T1 (median 0.70 mm); however, there was no statistically significant difference at any time point. The chin volume asymmetry score differed significantly between T0 (median 1.11 mm) and T1 and T2 (median 1.08 mm for both; P < 0.001 and P = 0.001, respectively), but not between T1 and T2 (P = 0.061). The study findings indicate that the asymmetry of the facial soft tissues has the potential to return after 6 months, without reaching the baseline.

Cloner 3D photogrammetric facial scanner: Assessment of accuracy in a controlled clinical study

OBJECTIVE

To evaluate the accuracy of facial measurements on three-dimensional images obtained using a new photogrammetric scanner.

MATERIAL AND METHODS

A total of 11 participants were included in the study. Nine customized adhesive labels were used to identify the facial landmarks: Trichion (Tri), Glabella (G), Right (Exr) and Left (Exl), Pronasal (Pn), Subnasal (Sn), Chelion right (Chr) and left (Chl) and Mentonian (Me). Two trained and calibrated examiners were responsible for performing seven linear measurements for each participant (Tri-G, Sn-Me, Exr-Exl, Chr-Chl, Exr-Chr, Exl-Chl, Pn-Sn) first with a digital caliper and later with a three-dimensional model obtained after digitalization with photogrammetric technology. The intraclass correlation coefficient (ICC), mean difference, SD, and Bland-Altman correlation were used to compare the measurements performed.

RESULTS

Intra and inter-examiner reliability were excellent (ICC >0.9). In general, the measurements presented a variation of a minor 2.0 mm. However, only three measures (Sn-Me, Exr-Exl, and Exr-Chr) were outside the clinical acceptability range.

CONCLUSIONS

The 3D Cloner scanner showed clinically acceptable accuracy comparable to the digital caliper with a variation of -0.8 ± 1.2 mm. Inter- and intra-examiner agreement on digital measurements was also observed.

CLINICAL SIGNIFICANCE

Scanners with accurate 3D model reproductions associated with reliable digital measurements provide a more precise diagnosis and better planning in orofacial treatment.

Accuracy of RGB-D camera-based and stereophotogrammetric facial scanners: a comparative study

OBJECTIVES

This study aimed to evaluate and compare the accuracy and inter-operator reliability of a low-cost red-green-blue-depth (RGB-D) camera-based facial scanner (Bellus3D Arc7) with a stereophotogrammetry facial scanner (3dMD) and to explore the possibility of the former as a clinical substitute for the latter.

METHODS

A mannequin head was selected as the research object. In the RGB-D camera-based facial scanner group, the head was continuously scanned five times using an RGB-D camera-based facial scanner (Bellus3D Arc7), and the outcome data of each scan was then imported into CAD software (MeshLab) to reconstruct three-dimensional (3D) facial photographs. In the stereophotogrammetry facial scanner group, the mannequin head was scanned with a stereophotogrammetry facial scanner (3dMD). Selected parameters were directly measured on the reconstructed 3D virtual faces using a CAD software. The same parameters were then measured directly on the mannequin head using the direct anthropometry (DA) method as the gold standard for later comparison. The accuracy of the facial scanners was evaluated in terms of trueness and precision. Trueness was evaluated by comparing the measurement results of the two groups with each other and with that of DA using equivalence tests and average absolute deviations, while precision and inter-operator reliability were assessed using the intraclass correlation coefficient (ICC). A 3D facial mesh deviation between the two groups was also calculated for further reference using a 3D metrology software (GOM inspect pro).

RESULTS

In terms of trueness, the average absolute deviations between RGB-D camera-based and stereophotogrammetry facial scanners, between RGB-D camera-based facial scanner and DA, and between stereophotogrammetry facial scanner and DA were statistically equivalent at 0.50±0.27 mm, 0.61±0.42 mm, and 0.28±0.14 mm, respectively. Equivalence test results confirmed that their equivalence was within clinical requirements (<1 mm). The ICC for each parameter was approximately 0.999 in terms of precision and inter-operator reliability. A 3D facial mesh analysis suggested that the deviation between the two groups was 0.37±0.01 mm.

CONCLUSIONS

For facial scanners, an accuracy of <1 mm is commonly considered clinically acceptable. Both the RGB-D camera-based and stereophotogrammetry facial scanners in this study showed acceptable trueness, high precision, and inter-operator reliability. A low-cost RGB-D camera-based facial scanner could be an eligible clinical substitute for traditional stereophotogrammetry.

CLINICAL SIGNIFICANCE

The low-cost RGB-D camera-based facial scanner showed clinically acceptable trueness, high precision, and inter-operator reliability; thus, it could be an eligible clinical substitute for traditional stereophotogrammetry.

Facial Scanners in Dentistry: An Overview

Purpose: This narrative review aims to explore the current status of facial scanning technology in the dental field; outlining the history, mechanisms, and current evidence regarding its use and limitations within digital dentistry. Methods: Subtopics within facial scanner technology in dentistry were identified and divided among four reviewers. Electronic searches of the Medline (PubMed) database were performed with the following search terms: facial scanner, dentistry, prosthodontics, virtual patient, sleep apnea, maxillofacial prosthetics, accuracy. For this review only studies or review papers evaluating facial scanning technology for dental or medical applications were included. A total of 44 articles were included. Due to the narrative nature of this review, no formal evidence-based quality assessment was performed and the search was limited to the English language. No further restrictions were applied. Results: The significance, applications, limitations, and future directions of facial scanning technology were reviewed. Specific subtopics include significant history of facial scanner use and development for dentistry, different types and mechanisms used in facial scanning technology, accuracy of scanning technology, use as a diagnostic tool, use in creating a virtual patient, virtual articulation, smile design, diagnosing and treating obstructive sleep apnea, limitations of scanning technology, and future directions with artificial intelligence. Conclusions: Despite limitations in scan quality and software operation, 3D facial scanners are rapid and non-invasive tools that can be utilized in multiple facets of dental care. Facial scanners can serve an invaluable role in the digital workflow by capturing facial records to facilitate interdisciplinary communication, virtual articulation, smile design, and obstructive sleep apnea diagnosis and treatment. Looking into the future, facial scanning technology has promising applications in the fields of craniofacial research, and prosthodontic diagnosis and treatment planning.

Evaluation of two stereophotogrametry software for 3D reconstruction of virtual facial models

Objective:

The present study aimed to evaluate the accuracy of 3D facial soft tissue virtual models produced by two photogrammetry softwares (AgiSoft Photoscan and 3DF Zephyr Free), when compared to those created by cone beam computed tomography (CBCT).

Methods:

Ten patients were submitted to two sequences of photographs performed with a DSLR camera (with and without the aid of a ring flash) and CBCT scans. Each photo series for each patient was processed with the softwares, and at the end, five models of each patient were generated: 1) CBCT, 2) AAL (Agisoft Ambient Light), 3) AFL (Agisoft Flash Light), 4) ZAL (Zephyr Ambient Light), and 5) ZFL (Zephyr Flash Light). Color coded maps and root-mean-square (RMS) distances were used to compare the photogrammetry models to the CBCT ones.

Results:

One sample t-test showed significant differences between all methods versus CBCT. The worst results were seen in the ZAL group (discrepancies up to 5.17mm), while the best results were produced by AAL group (discrepancies up to 2.11mm).

Conclusions:

It can be concluded that this type of virtual facial models are reasonably accurate, although not perfect, and considering its lower biological and financial cost, they may play an important role in specific situations.

Precision and accuracy assessment of single and multicamera three-dimensional photogrammetry compared with direct anthropometry

OBJECTIVES

To assess the precision and accuracy of single-camera photogrammetry (SCP) and multicamera photogrammetry (MCP) compared with direct anthropometry (DA).

MATERIALS AND METHODS

A total of 30 participants were recruited, and 17 soft tissue landmarks were identified and used to complete a total of 16 measurements. Using SCP and MCP, two three-dimensional (3D) images were acquired from each participant. All 3D measurements and direct measurements were measured twice by the same operator to assess intraexaminer repeatability. Intraclass coefficients (ICCs) were used to evaluate intraexaminer repeatability and interexaminer agreement of the methods. Nonparametric bootstrap analyses were used to compare the means of the measurements among the three methods.

RESULTS

All three methods showed excellent intraexaminer repeatability (ICCs > 0.90), except interpupillary distance (ICC = 0.86) measured by SCP. Both SCP and MCP showed excellent interexaminer agreement (ICCs > 0.90), except interpupillary distance (ICC = 0.79), left gonion-pogonion (ICC = 0.74), and columella-subnasale-labrale superior angle (ICC = 0.86) measured by SCP. Overall, there was good agreement between methods, except for columella-subnasale-labrale superior angle (ICC = 0.40) between SCP and MCP.

CONCLUSIONS

Both SCP and MCP techniques were found to be reliable and valid options for 3D facial imaging. SCP produced slightly larger mean values for several measurements, but the differences were within a clinically acceptable range. Because of the larger margin of errors, measurements including the gonial area and subnasale should be assessed with caution.

Portable three-dimensional imaging to monitor small volume enhancement in face, vulva, and hand: A comparative study

Multiple handheld three-dimensional (3D) systems are available on the market, but data regarding their use in detecting small volumes are limited. The aim of this study was to compare different portable 3D technologies in detecting small volumetric enhancement on a mannequin model and a series of patients. Five portable 3D systems (Artec Eva, Crisalix, Go!Scan, LifeViz Mini, and Vectra H1) were tested in a controlled environment with standardised volumes and in a clinical setting with patients undergoing small volume fat grafting to face, vulva, and hand. Accuracy was assessed with absolute and relative technical error measurement (TEM and rTEM); precision with intra- and inter-observer reliability (r_p and ICC); and usability in clinical practice with the following parameters: portability, suitability of use in operating theatre/clinic, ease of use of hardware and software, speed of capture, image quality, patient comfort, and cost. All tested devices presented overall good accuracy in detecting small volumetric changes ranging from 0.5 to 4 cc. Structured-light laser scanners (Artec Eva and Go!Scan) showed high accuracy, but their use in clinical practice was limited by longer capture time, multiple wiring, and complex software for analysis. Crisalix was considered the most user-friendly, less bothering for patients, and truly portable, but its use was limited to the face because the software does not include vulva and hand. Three-dimensional technologies exploiting the principle of passive stereophotogrammetry such as LifeViz Mini and Vectra H1 were the most versatile for assessing accurately multiple body areas, representing overall the best long-term value for money. Therefore, 3D portable technology is a non-invasive, accurate, and reproducible method to assess the volumetric outcome after facial, vulval, and hand injectables. The choice of the 3D system should be based on the clinical need and resources available.

The Vectra M3 3-dimensional digital stereophotogrammetry system: A reliable technique for detecting chin asymmetry

Purpose

The aim of this study was to evaluate the reliability of the Vectra M3 (3D Imaging System; Canfield Scientific, Parsippany, NJ, USA) in detecting chin asymmetry, and to assess whether the automatic markerless tracking function is reliable compared to manually plotting landmarks.

Materials and Methods

Twenty subjects (18 females and 2 males) with a mean age of 42.5±10.5 years were included. Three-dimensional image acquisition was carried out on all subjects with simulated chin deviation in 4 stages (1-4 mm). The images were analyzed by 2 independent observers through manually plotting landmarks and by Vectra software auto-tracking mode. Repeated-measures analysis of variance and the Tukey post-hoc test were performed to evaluate the differences in mean measurements between the 2 operators and the software for measuring chin deviation in 4 stages. The intraclass correlation coefficient (ICC) was calculated to estimate the intra- and inter-examiner reliability.

Results

No significant difference was found between the accuracy of manually plotting landmarks between observers 1 and 2 and the auto-tracking mode (P=0.783 and P=0.999, respectively). The mean difference in detecting the degree of deviation according to the stage was <0.5 mm for all landmarks.

Conclusion

The auto-tracking mode could be considered as reliable as manually plotted landmarks in detecting small chin deviations with the Vectra® M3. The effect on the soft tissue when constructing a known dental movement yielded a small overestimation of the soft tissue movement compared to the dental movement (mean value<0.5 mm), which can be considered clinically non-significant.

Three-Dimensional Digital Image Analysis of Skeletal and Soft Tissue Points A and B after Orthodontic Treatment with Premolar Extraction in Bimaxillary Protrusive Patients

Aim. To investigate the effect of changes in incisor tip, apex movement, and inclination on skeletal points A and B and characterize changes in skeletal points A and B to the soft tissue points A and B after incisor retraction in Angle Class I bimaxillary dentoalveolar protrusion. Methods. Twenty-two patients with Angle Class I bimaxillary dentoalveolar protrusion treated with four first premolar extractions were included in this study. The displacement of skeletal and soft tissue points A and B was measured using cone-beam computed tomography (CBCT) using a three-dimensional coordinate system. The movement of the upper and lower incisors was also measured using CBCT-synthesized lateral cephalograms. Results. Changes in the incisal tip, apex, and inclination after retraction did not significantly affect the position of points A and B in any direction (x, y, z). Linear regression analysis showed a statistically significant relationship between skeletal point A and soft tissue point A on the anteroposterior axis (z). Skeletal point A moved forward by 0.07 mm, and soft tissue point A moved forward by 0.38 mm, establishing a ratio of 0.18: 1 (r = 0.554, p < 0.01). Conclusion. The positional complexion of the skeletal points A and B was not directly influenced by changes in the incisor tip, apex, and inclination. Although the results suggest that soft tissue point A follows the anteroposterior position of skeletal point A, its clinical significance is suspected. Thus, hard and soft tissue analysis should be considered in treatment planning.

Use of facial stereophotogrammetry as a screening tool for pediatric obstructive sleep apnea by dental specialists

STUDY OBJECTIVES

To evaluate facial 3-dimensional (3D) stereophotogrammetry's effectiveness as a screening tool for pediatric obstructive sleep apnea (OSA) when used by dental specialists.

METHODS

One hundred forty-four participants aged 2-17 years, including children fully diagnosed with pediatric OSA through nocturnal polysomnography or at high-risk or low-risk of pediatric OSA, participated in this study. 3D stereophotogrammetry, Craniofacial Index, and Pediatric Sleep Questionnaire were obtained from all participants. Ten dental specialists with interest in pediatric sleep breathing disorders classified OSA severity twice, once based only on 3D stereophotogrammetry and then based on 3D stereophotogrammetry, Craniofacial Index, and Pediatric Sleep Questionnaire. Intrarater and interrater reliability and diagnostic accuracy of pediatric OSA classification were calculated. A cluster analysis was performed to identify potential homogeneous pediatric OSA groups based on their craniofacial features classified through the Craniofacial Index .

RESULTS

Intrarater and interrater agreement suggested a poor reproducibility when only 3D facial stereophotogrammetry was used and when all tools were assessed simultaneously. Sensitivity and specificity varied among clinicians, indicating a low screening ability for both 3D facial stereophotogrammetry, ranging from 0.36-0.90 and 0.10-0.70 and all tools ranging from 0.53-1.0 and 0.01-0.49, respectively. A high arched palate and reversed or increased overjet contributed to explaining how participating dental clinicians classified pediatric OSA.

CONCLUSIONS

3D stereophotogrammetry-based facial analysis does not seem predictive for pediatric OSA screening, alone or combined with the Pediatric Sleep Questionnaire and Craniofacial Index when used by dental specialists interested in sleep-disordered breathing. Some craniofacial traits, more specifically significant sagittal overjet discrepancies and an arched palate, seem to influence participating dental specialists' classification.

CITATION

Fernandes Fagundes NC, Carlyle T, Dalci O, et al. Use of facial stereophotogrammetry as a screening tool for pediatric obstructive sleep apnea by dental specialists. J Clin Sleep Med. 2022;18(1):57-66.

Scleral exposure changes after Le Fort I maxillary advancement with vertical component in individuals with skeletal Class III malocclusion-A stereophotogrammetric image study

OBJECTIVE

This retrospective study aimed to evaluate inferior scleral exposure changes in Class III patients that underwent orthognathic surgery with Le Fort I osteotomy with and without vertical displacement.

MATERIALS AND METHODS

Preoperative and 6-months postoperative cephalograms and stereophotogrammetric images of 45 subjects (mean age:21.66±2.97 years) that underwent orthognathic surgery for Class III correction were retrieved. Subjects were divided into 3 groups: maxillary advancement-only (AO); maxillary advancement+impaction (AI), maxillary advancement+downfracture (AD). Exclusion criteria were mandibular-only surgery, occlusal canting, facial asymmetry, orbital surgery, and craniofacial syndrome. One investigator measured inferior scleral exposure on both sides using following landmarks: upper eyelid margin (A), inferior limbus (B) and lower eyelid margin (C). Distance between A and C was recorded as overall eye height (E), distance between B and C was recorded as inferior sclera exposure (S). S:E ratio in percentage was calculated to standardize sclera exposure relative to overall eye height. Wilcoxon signed-rank and Kruskal Wallis tests were used for statistical analysis (p<0.05).

RESULTS

Mean value of maxillary movements were: 4.21±1.82mm advancement in AO; 5.08±2.18mm advancement and 2.33±0.99mm impaction in AI; 3.95±1.45mm advancement and 3.1±0.71mm downfracture in AD. Change in reduction of scleral exposure was significant in all groups (p<0.05). AI group bilaterally and AO group right side had highest differences (-4.96±4.86, -6.09±4.21, -4.99±3.23, respectively). There was no significant difference between groups in S:E ratio changes (p>0.05).

CONCLUSION

Intergroup comparisons showed no statistically significant difference, revealing similar reduction in all three groups despite the differences in the vertical movement variable.

Current and Future Photography Techniques in Aesthetic Surgery

Background

The rapidly increasing modalities and mediums of clinical photography, use of 3-dimensional (3D) and 4-dimensional (4D) patient modeling, and widening implementation of cloud-based storage and artificial intelligence (AI) call for an overview of various methods currently in use as well as future considerations in the field.

Objectives

Through a close look at the methods used in aesthetic surgery photography, clinicians will be able to select the modality best suited to their practice and goals.

Methods

Review and discussion of current data pertaining to: 2-dimensional (2D) and 3D clinical photography, current photography software, augmented reality reconstruction, AI photography, and cloud-based storage.

Results

Important considerations for current image capture include a device with a gridded viewing screen and high megapixel resolution, a tripod with leveling base, studio lighting with dual-sourced light, standardized matte finish background, and consistency in patient orientation. Currently, 3D and 4D photography devices offer advantages such as improved communication to the patient on outcome expectation and better quality of patient service and safety. AI may contribute to post-capture processing and 3D printing of postoperative outcomes. Current smartphones distort patient perceptions about their appearance and should be used cautiously in an aesthetic surgery setting. Cloud-based storage provides flexibility, cost, and ease of service while remaining vulnerable to data breaches.

Conclusions

While there are advancements to be made in the physical equipment and preparation for the photograph, the future of clinical photography will be heavily influenced by innovations in software and 3D and 4D modeling of outcomes.

Evaluating the agreement and reliability of a web-based facial analysis tool for rhinoplasty

PURPOSE

Rhinoplasty is one of the most common and challenging plastic surgery procedures. Facial analysis is a crucial step in planning. Utilizing three-dimensional (3D) model of a patient's face is an emerging way of performing facial analysis. This paper evaluates the agreement and reliability of facial measurements taken using a web app, located at digitized-rhinoplasty.com, that utilizes 3D models of the patient's face.

METHODS

Eleven measurements were calculated on 16 human subjects. Three methods of measurements were performed: direct measurements on human subjects' faces, measurements on 2D photographs, and measurements on 3D models of face scans. The Bland-Altman plot is used for testing the agreement between the web app and the well-known Blender 3D modeling software. Intra-rater and inter-rater reliability was calculated and compared for 2D and 3D methods using the intraclass correlation coefficient (ICC) method. The statistical analysis methods were checked for the normality and homoscedasticity assumptions.

RESULTS

The results indicate that the web app and Blender software show agreement within 95% confidence limits. The web app performs well in intra-rater and inter-rater reliability statistical analysis. The web app's reliability scores are consistently better than facial analysis software which was found highly reliable in a previous study. We also compare the methods of measurements in terms of time, ease of use, and cost.

CONCLUSION

The utilization of 3D computer modeling for facial analysis has its advantages and started to become more common due to recent advances in technology. The web app utilizes 3D face scans for pre-operative planning and post-operative evaluation of facial surgeries. The web app performs well in agreement and inter-/intra-reliability analysis and performs consistently better than software that works utilizing 2D photographs. The web app provides accurate, repeatable, affordable, and fast facial measurements for facial analysis when compared to direct and 2D methods.

Three-dimensional soft tissue changes in orthodontic extraction and non-extraction patients: A prospective study

OBJECTIVES

To assess the soft tissue changes in orthodontic extraction and non-extraction patients on 3D stereophotogrammetric images.

SETTING AND SAMPLE

23 extraction (22.2 ± 9.2 years) and 23 non-extraction (20.3 ± 11.1 years) consecutive patients were enrolled at the Sections of Orthodontics at Aarhus University and at University of Naples Federico II.

METHODS

All patients had a first 3D image taken after bonding of brackets on the upper incisors (T0), and a second 3D image (T1) after space closure in the extraction group or at insertion of the first SS or TMA rectangular wire in the non-extraction group. The 3D images were captured with 3dMDFace System and analysed with 3dMDVultus Software. After placing 19 landmarks, 15 measurements were obtained. Intragroup changes were analysed with paired t-test and intergroup changes with unpaired t-test (P < .05).

RESULTS

Superimpositions of the 3D images at T0 and T1 visualized with colour-coded maps showed that soft tissue changes primarily happened in the perioral area in both groups. The Nasolabial angle increased significantly in the extraction group (3°± 4.1, P = .002), while it decreased in the non-extraction group (-1.5°± 5.5°, P = .002). There was a significant difference between the two groups (4.4°, P = .004).

CONCLUSIONS

3D comparison of the soft tissues in the extraction and non-extraction groups showed statistically significant, but clinically limited differences in the perioral area. The Nasolabial angle was significantly larger at T1 in the extraction group compared with the non-extraction group.

Comparison of three-dimensional soft-tissue evaluations between skeletal and pseudo-class III malocclusions

The aim of our study was to compare soft tissue measurements with 3D imaging methods in individuals with untreated skeletal and pseudo-Class III malocclusions. The study sample consisted of 75 patients (38 males, 37 females, mean age 12.41 ± 2.35 years) with pseudo- and true skeletal Class III malocclusions and skeletal Class I malocclusions. Soft tissue evaluations of all patients were performed using 3D stereophotogrammetric facial images. In our study, 26 landmarks, 17 linear measurements, 13 angular measurements, and 5 volume measurements were made using the 3dMD Vultus software. The significance was determined to be p < 0.05 in ANOVA, Tukey tests. No significant differences were found among the groups in terms of demographic data (p > 0.05). The skeletal Class I control group had a significantly more extended upper lip and vermillion length as compared to the Class III groups. The soft tissue convexity angle and upper nasal angle were found to be wider in the Class III malocclusion group compared to those in the Class I control group. While the pseudo-Class III group had a significantly lower midface volume, chin volume was significantly higher in the skeletal class group. Upper lip volume was significantly higher in the Class I group. Using 3dMD for guiding clinicians in the differential soft and hard tissue diagnosis of pseudo-Class III malocclusions, differences were revealed in Class I patients in the middle part of the face. In the differential diagnosis of true Class III malocclusions, chin volume was found to be different from that of Class I patients.

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.

A Prospective Study Comparing Adolescent and Post-Adolescent Periods Regarding Effects of Activator Appliance in Patients with Class II Mandibular Retrognathia by Using 3dMDface Analysis and Cephalometry

BACKGROUND The purpose of this prospective study was to compare adolescent and post-adolescent growth periods regarding the effectiveness of conventional activator appliance in patients with Class II mandibular retrognathia by using lateral cephalometric radiographs and three-dimensional photogrammetry (3dMDface). MATERIAL AND METHODS We enrolled 2 groups: 15 patients in the adolescent growth period and 17 patients in the post-adolescent growth period. All patients had Class II anomaly with mandibular retrognathia and were treated with conventional activator appliances. Lateral cephalometric radiographs and three-dimensional photogrammetric views were obtained at the beginning and end of the activator treatment of Class II patients. Maxillomandibular discrepancy, mandibular protrusion and lengths, convexity angles, facial heights, and dental measurements were evaluated cephalometrically. Projections of the lips and the chin and volumetric measurements of the lip and the mandibular area were assessed using three-dimensional photogrammetry. RESULTS Conventional activator therapy resulted in similar effects in both growth periods regarding improvements in the mandibular sagittal growth and maxillomandibular relationship (ANB° and the SNB° angles). Mandibular effective length was increased (Co-Gn length) and the maxillary horizontal growth was restricted (decreased SNA° angle) in both groups following the treatment. Treatment duration was significantly longer in the post-adolescent group. Increases in the projections of menton, pogonion, and sublabial points were observed in the three-dimensional photogrammetric views. Total lip volume was reduced while the mandibular volume was significantly increased in both groups. Lower gonial angle showed a greater increase in the post-adolescent group. CONCLUSIONS Correction of Class II anomaly with mandibular retrognathia was achieved with a combination of dental and skeletal changes in both growth periods. Conventional activator therapy may be an alternative treatment approach in the late growth period as it led to significant skeletal and dental changes.

Assessing the Influence of Chin Asymmetry on Perceived Facial Esthetics With 3-Dimensional Images

PURPOSE

We used 3-dimensinonal (3D) images to assess the influence of chin asymmetry on perceived facial esthetics, investigate the cognitive boundaries of chin asymmetry among orthodontists, general dentists, and laypersons, and provide quantitative reference for clinical treatment.

MATERIALS AND METHODS

A 3D facial image was obtained using the 3dMD imaging system (3dMD, Atlanta, GA). The chin was altered in 2-mm increments from 0 to 12 mm and to the left and right using the software program. These images were rated by 66 orthodontists, 89 general dentists, and 66 laypersons as 1) chin symmetry; 2) slight chin asymmetry but acceptable; and 3) serious asymmetry and treatment needed. Multivariate mixed linear regression and multivariate mixed logistic regression analyses were used for statistical data analysis. Descriptive and bivariate statistics were calculated, and statistical significance was considered present at P = .05.

RESULTS

The observers progressively increased the grade ratings and the desire for surgery for greater asymmetries (P < .001). Orthodontists and general dentists could perceive a chin deviation of 4 mm to the right and 2 mm to the left, with 8-mm deviation considered to require treatment. Laypersons had a clear perception of a 4-mm chin deviation, with 8 mm to the right and 10 mm to the left considered to require treatment. The right chin deflection was more easily perceived than was the left (P < .05).

CONCLUSIONS

Chin asymmetry has a great influence on facial esthetics. We found a statistically significant difference between clinicians (orthodontists and general dentists) and laypersons in the cognition of chin asymmetry and the recommendations for treatment.

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.

Two-dimensional versus three-dimensional Frӓnkel Manoeuvre: a reproducibility study

Background/Objectives

To assess intra- and inter-observer reproducibility of the evaluation of the Frӓnkel Manoeuvre (FM) on three-dimensional (3D) scans and to compare it to the assessment on two-dimensional (2D) pictures.

Materials/Methods

This study included 44 individuals with a skeletal Class II malocclusion [9–16-years old mean age ± standard deviation: 13.5 ± 2.01 years]. All patients had a full Class II molar relationship, overjet ≥6 mm and point A, Nasion, point B angle (ANB) ≥5 degrees. During the FM, each patient was invited to bite in centric occlusion and then to posture the mandible forward to reach a Class I molar relationship. The FM was recorded both by a normal camera and a 3D scanner (3dMD system). Six examiners divided into two groups according to their orthodontic clinical experience (&lt;5 and &gt;10 years), and one gold standard in the evaluation of FM, commented twice (every 15 days) on both 2D photographs (T0 and T2) and 3D scans (T1 and T3). The intra-observer agreement and the inter-observer agreement compared to the gold standard were evaluated by computing the Cohen’s K.

Results

The agreement between observations for each examiner ranged from 0.36 to 1 on 2D pictures (T0 versus T2), and from 0.22 to 0.69 on 3D scans (T1 versus T3). The overall agreement was 0.63 (95 per cent CI = 0.35–0.91) in 2D analysis and 0.5 (95 per cent CI = 0.35–0.64) in 3D analysis.

Conclusions/Implications

The FM was less reproducible when performed on 3D records than on 2D pictures.

The Esthetic Difference of Chinese Beauty Evaluated by Two Different Human Races Based on Three-Dimensional Average Face Analysis

Supplemental Digital Content is available in the text

Purpose:

The aim of this study was to establish a new method of facial soft tissue analysis based on 3dMDface system and to find the different esthetic preferences of Chinese beauties from the Chinese and Indian evaluators perspective.

Methods:

Three-dimensional facial images of 242 females and 168 males were evaluated and ranked by 8 Chinese and nine Indians using a 10-point visual analog scale (VAS). Total 120 subjects in 2 panels (from Chinese perspective and Indian perspective) including 30 male and 30 female faces with top 30 scores were analyzed with the “average face” method respectively. Then 17 linear measurements, 13 curve measurements and 14 ratios of 4 average faces were calculated and compared with the divine proportion.

Results:

Distinct differences were founded based on the average face analysis. Similar total facial types were preferred by both Chinese and Indian evaluators, while Indian evaluators preferred a wider male face with a protrusive lower lip. Delicate noses with lower nose ridge but protrusive lower lips in females were more acceptable by Indian evaluators. The differences of linear measurements were limited in 2.0 mm except the facial width, lower facial width, upper facial height and forehead height while curve measurements differ distinctly as the table shows. No ratios equal to the divine proportion were founded.

Conclusion:

The 3D Average face based on stereophotogrammetry is a feasible method to analyze the facial characters and discrepancy of esthetic preferences. Chinese and Indian evaluators have some certain differences when judging beauties. Attractive faces have some certain ratios but not the divine proportion.

Volumetric Analysis of Fat Injection by Computerized Tomography in Orthognathic Surgery: Preliminary Report on a Novel Volumetric Analysis Process for the Quantification of Aesthetic Results

BACKGROUND

Integrated approaches to orthognathic surgery should include accurate volumetric evaluation of the skull and soft tissues. In patients with dentofacial deformities, the most frequent aesthetic deficits are attributable to an underdevelopment of hard and soft tissues. Traditional osteotomic procedures often fail to guarantee a stability of soft tissues over time. For this reason, in selecting a surgical strategy, the surgeon should consider not only traditional osteotomies, but also soft-tissue improving procedures, such as lipofilling. Preoperative surgical planning systems, such as the Virtual surgical planning (VSP) protocol, are based mainly on skeletal movement prediction. Quantitative estimation of soft-tissue modifications is not part of common clinical practice. Most commonly, the evaluation of soft-tissue modifications after orthognathic procedures is instead performed by clinical qualitative means.The purpose of this study was to describe a novel computed tomography (CT)-based volumetric analysis process for the quantification of injected autologous adipose tissue in patients who have undergone simultaneous orthognathic and lipofilling procedures.

METHODS

This was a retrospective review of consecutive patients who underwent combined orthognathic surgery and lipofilling from June 2016 to May 2017 for malocclusion with functional and aesthetic impairments. Preoperative planning included clinical evaluation and virtual osteotomy planning according to the VSP protocol. The volume of fat to be injected was estimated clinically by comparing virtual renderings with preoperative clinical photographs. The surgical technique involved Le Fort I and sagittal split mandibular osteotomies, combined with autologous fat injection in the malar and perioral regions. Postoperative evaluation was performed with a novel imaging process based on CT image segmentation to quantify the exact volume of injected fat. Skeletal stability was also evaluated at 3 months.

RESULTS

Sixteen patients were enrolled in the study, all females, with a mean age of 24.5 years (range, 18-36 years). The mean difference between the fat tissue injected and that quantified postoperatively was 6.01 cm. All patients had clinically satisfactory facial convexity, with complete restoration of the cheekbone contour, at 3 months.

CONCLUSION

This study introduces a novel CT-image based technique to quantitatively assess the contribution of injected fat to the postoperative soft-tissue volume increase after combined orthognathic surgery with autologous lipofilling. In the future, this CT-based volumetric analysis technique could be the gold standard for evaluating facial lipofilling outcomes, and for assessing clinical aesthetic outcomes based on the injected volume of fat.