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

Monolithic zirconia and digital impression: case report

The aim of this study is to present a clinical case of a full arch prosthetic rehabilitation on natural teeth, combining both digital work-flow and monolithic zirconi

3D surface acquisition systems and their applications to facial anatomy : let’s make a point

In the last decades 3D optical devices have gained a primary role in facial anthropometry, where they find several applications from the anatomical research to clinics and surgery. With time the number of articles focusing on 3D surface analysis has raised, as well as validation studies which aim at verifying the reliability of different devices and methods of acquisition in comparison with other methods or direct anthropometry. This review aims at making a point in the field of 3D surface acquisition systems, describing the most used types of available devices and comparing the relevant outcomes in acquiring 3D facial models. Results show that currently stereophotogrammetric devices represent the gold standard, further improved by the diffusion of portable models. Caution should be given to the use of low-cost devices, more and more frequently described by literature, as often they do not meet the basic criteria for being applied to the anatomical study of face

Portable Three-Dimensional imaging to monitor small volume enhancement in face, vulva and hand: a comparative study

Multiple handheld 3-dimentional 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 (rp 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. 3D 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. 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

Evaluation of fit for 3D printed retainers as compared to thermoform retainers

ABSTRACT EVALUATION OF FIT FOR 3D PRINTED RETAINERS AS COMPARED TO THERMOFORM RETAINERS By David Cole, D.M.D. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Dentistry at Virginia Commonwealth University Thesis Directors: Eser Tüfekçi, D.D.S., M.S., Ph.D., M.S.H.A. Professor, Department of Orthodontics Sompop Bencharit, D.D.S., M.S., Ph.D. Associate Professor and Director of Digital Dentistry, Department of General Practice Introduction: Despite recent advances in three-dimensional (3D) printing, little information is available on 3D printed retainers Methods: Three reference models were used to fabricate traditional vacuum formed, commercially-available vacuum formed, and 3D printed retainers. For each model, three retainers were made using the three methods (a total of 27 retainers). To determine the trueness, the distances between the intaglio surface of the retainers and the occlusal surface of the reference models were measured using an engineering software. A small difference was indicative of a good fit. Results: Average differences of the traditional vacuum formed retainers ranged from 0.10 to 0.20mm. The commercially-available and 3D printed retainers had a range of 0.10 to 0.30mm and 0.10 to 0.40mm, respectively. Conclusions: The traditional vacuum formed retainers showed the least amount of deviation from the original reference models while the 3D printed retainers showed the greatest deviation

Validation of the automatic tracking for facial landmarks in 3D motion captured images

Aim: The aim of this study was to validate the automatic tracking of facial landmarks in 3D image sequences captured using the Di4D system (Dimensional Imaging Ltd., Glasgow, UK). MATERIALS AND METHODS: 32 subjects (16 males; 16 females) range 18-35 years were recruited. 23 facial landmarks were marked on the face of each subject with a 0.5 mm non-permanent ink. The subjects were asked to perform three facial animations from the rest position (maximal smile, lip purse and cheek puff). Each animation was captured by a 3D stereophotogrammetry video system (Di4D). A single operator digitized landmarks on captured 3D models and the manual digitised landmarks were compared with the automatic tracked landmarks. To investigate the accuracy of manual digitisation, the same operator re-digitized 2 subjects (1 male and 1 female). RESULTS & CONCLUSION: The discrepancies in x, y and z coordinates between the manual digitised landmarks and the automatic tracked facial landmarks were within 0.5 mm and the mean distance between the manual digitisation and the automatic tracking of corresponding landmarks using tracking software was within 0.7 mm which reflects the accuracy of the method( p value was very small). The majority of these distances were within 1 mm. The correlation coefficient between the manual and the automatic tracking of facial landmarks was 0.999 in all x, y, and z coordinates. In conclusion, Automatic tracking of facial landmarks with satisfactory accuracy, would facilitate the analysis of the dynamic motion during facial animations

How to Obtain an Orthodontic Virtual Patient through Superimposition of Three-Dimensional Data: A Systematic Review

Background: This systematic review summarizes the current knowledge on the superimposition of three-dimensional (3D) diagnostic records to realize an orthodontic virtual patient. The aim of this study is to analyze the accuracy of the state-of-the-art digital workflow. Methods: The research was carried out by an electronic and manual query eectuated from ISS (Istituto Superiore di Sanit\ue0 in Rome) on three dierent databases (MEDLINE, Cochrane Library and ISI WEB OF SCIENCE) up to 31st January 2020. The search focused on studies that superimposed at least two dierent 3D records to build up a 3D virtual patient\u2014information about the devices used to acquire 3D data, the software used to match data and the superimposition method applied have been summarized. Results: 1374 titles were retrieved from the electronic search. After title-abstract screening, 65 studies were selected. After full-text analysis, 21 studies were included in the review. Dierent 3D datasets were used: facial skeleton (FS), extraoral soft tissues (ST) and dentition (DENT). The information provided by the 3D data was superimposed in four dierent combinations: FS + DENT (13 papers), FS + ST (5 papers), ST + DENT (2 papers) and all the types (FS + ST + DENT) (1 paper). Conclusions: The surface-based method was most frequently used for 3D objects superimposition (11 papers), followed by the point-based method (6 papers), with or without fiducial markers, and the voxel-based method (1 paper). Most of the papers analyzed the accuracy of the superimposition procedure (15 papers), while the remaining were proof-of-principles (10 papers) or compared dierent methods (3 papers). Further studies should focus on the definition of a gold standard. The patient is going to have a huge advantage from complete digital planning when more information about the spatial relationship of anatomical structures are needed: ectopic, impacted and supernumerary teeth, root resorption and angulations, cleft lip and palate (CL/P), alveolar boundary conditions, periodontally compromised patients, temporary anchorage devices (TADs), maxillary transverse deficiency, airway analyses, obstructive sleep apnea (OSAS), TMJ disorders and orthognathic and cranio-facial surgery