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Facial Scanner Accuracy with Different Superimposition Methods: An In Vivo Study
Abstract
Purpose:
To compare trueness and precision between conventional and digital facial measurements and to evaluate the accuracy of different superimposition techniques for facial scans.
Materials and methods:
Twenty volunteers were recruited. Predetermined facial landmarks were marked with a black pen, and the interlandmark distances were measured manually with a conventional caliper and digitally with Geomagic software. Two consecutive facial scans were performed and superimposed using as best-fit reference the full face, the face without the eyes, and the bone-supported areas (eg, forehead and zygomatic areas) in order to assess root mean square (RMS) differences. Trueness and precision were evaluated and compared between the conventional and digital techniques. Mann-Whitney U and Kruskal-Wallis post hoc tests were used. The significance level was established at α = .05.
Results:
Trueness between conventional and digital measurements was 1,151.75 ± 1,265.52 μm (3.04% ± 4.82%), and precision was 322.31 ± 300.54 μm (0.93% ± 1.10%). Global mean RMS values for each superimposition technique were 334.15 ± 172.07 for the full face, 339.57 ± 173.13 for the face without the eyes, and 385.65 ± 182.29 for the bone-supported areas, with the latter presenting statistically significant differences compared to the other two.
Conclusion:
Although statistically significant differences were detected in facial measurements, they were below the clinically detectable threshold. Superimposition with the full face and the face without the eyes area presented smaller discrepancies than with the bone-supported areas, with higher discrepancies in the lower third of the face.
... Bellus3D Dental Pro is available as a free download for basic features offering in-app purchase for advanced functionalities. This face scan system has been reported to allow trueness and precision in a clinically acceptable range [21,22]. The design of the Mask Fitter has different options. ...
... Only 10% reported that they would not use the Mask Fitter ( Figure 10). Question (22) invited free text feedback from the participants on the reasons for their responses to question 21. The reasons for not adopting the routine use of the Mask Fitter were that people feel sufficiently safe with the FFP2 alone. ...
... Even if the distribution of the fifteen answers related to fogging was quite widespread, the effect of the Mask Fitter looked beneficial. Without the Mask Fitter (question 25), the participants Question (22) invited free text feedback from the participants on the reasons for their responses to question 21. The reasons for not adopting the routine use of the Mask Fitter were that people feel sufficiently safe with the FFP2 alone. ...
COVID-19 has deeply impacted clinical strategies in dentistry and the use of surgical masks and respirators has become critical. They should adapt to the person’s facial anatomy, but this is not always easy to achieve. Bellus3D Company proposed to apply their face scan software, used with selected smartphones and tablets, to design and 3D-print a bespoke “Mask Fitter” to improve the sealing of surgical masks and respirators. Twenty dental staff participants were face scanned and a Mask Fitter for FFP2 respirators was designed and 3D-printed. Participants were asked to wear their Mask Fitter over one week and then completed a survey. Questions were asked about wearing comfort, sealing confidence, glasses or loupes fogging, both with and without the Mask Fitter. Dental staff gave positive feedback, with levels of comfort during daily use reported as similar with and without the Mask Fitter; and a higher confidence in achieving a proper seal, ranging from a 10% confidence rating of a proper seal without the Mask Fitter to 75% with the Mask Fitter. Moreover, fogging problems decreased considerably. The tested Mask Fitter device could represent an easy and low-cost procedure to improve the facial adaptation of the FFP2 respirator.
... However, since distinctive and standardized boundaries on the face are absent, segmenting the area would not be objective. Moreover, other studies show that measuring points have adequate reliability [25,31,32]. ...
Background: Multi-dimensional facial imaging is increasingly used in hospital clinics. A digital twin of the face can be created by reconstructing three-dimensional (3D) facial images using facial scanners. Therefore, the reliability, strengths, and weaknesses of scanners should be investigated and approved; Methods: Images obtained from three facial scanners (RayFace, MegaGen, and Artec Eva) were compared with cone-beam computed tomography images as the standard. Surface discrepancies were measured and analyzed at 14 specific reference points; Results: All scanners used in this study achieved acceptable results, although only scanner 3 obtained preferable results. Each scanner exhibited weak and strong points because of differences in the scanning methods. Scanner 2 exhibited the best result on the left endocanthion; scanner 1 achieved the best result on the left exocanthion and left alare; and scanner 3 achieved the best result on the left exocanthion (both cheeks); Conclusions: These comparative analysis data can be used when creating digital twins through segmentation, selecting and merging data, or developing a new scanner to overcome all shortcomings.
... They reported statistically significantly higher accuracy when the complete facial surface was used in alignment procedures. 40 Best-fit alignment algorithm using complete data sets as opposed to surface landmarks has also been shown to produce higher trueness and precision in in-vitro studies on both single teeth and complete arch alignment cases. 41,42 In the present study, a thin layer of anti-reflex aerosol was sprayed onto the surface of the face including the metal spheres. ...
A mannequin head was digitized using a reference scanner (Scan in a Box) to acquire the reference mesh. Subsequently it was scanned with a structured light scanner (Einscan Pro HD), a stereophotogrammetry scanner (RayFace100) and a laser scanner (Proface 3D Mid) to acquire test meshes.Resulting meshes were delineated in four horizontal areas and discrepancies calculated for the complete face and different facial partitions. One-way Anova and pairwise comparisons tests were used to compare trueness and precision between scanners across different areas. Significant differences were detected among scanners for complete face (F (3, 27) =776, P ⟨ 0.01)) and for delineated face areas (F (11, 99) =200.1, P ⟨ 0.01)). Einscan had significantly higher accuracy for the complete face (P⟨0.01) and significantly higher trueness for each facial partition compared to other scanners. RayFace had significantly higher trueness when scanning the middle part of face compared to other facial parts. Proface had significantly lower upper facial third trueness compared to other facial parts. All scanners had accuracy levels below the 2.00mm threshold. Facial scanning accuracy was influenced per scanner used. Scanning trueness per device was influenced by location of surface area. All scanners had accuracy levels within the acceptable accuracy threshold.
... Consequently, the null hypothesis was accepted. Data confirmed that the proposed protocol can be suitable for the clinical use with excellent clinical outcomes as showed in Fig 3 and 4. Similar study [36][37] showed that face scans alignment accuracy using best fit technique on bone supported areas (e.g forehead and zygomatic area) results in clinically undetectable discrepancies. Advantages of the proposed technique are in the low cost and in the shallow learning curve needed to the clinicians. ...
Objectives
: Face scans are currently used in dentistry to obtain a virtual patient. Find stable and repeatable references for their matching is a fundamental step. Aim of this study is to evaluate matching reliability of multiple face scans using frontal adhesives references. Null hypothesis was that no significant discrepancy could be detected between the references position analyzed both with surface analysis and linear analysis.
Materials and Methods
: Nine patients were enrolled for this study and nine soft tissue adhesives landmarks (APLI Paper S.A.U, 4 mm Ø) placed, equally distributed, on the forehead and glabella. Patients were digitally scanned with a portable scanner (iPad Pro 3rd Gen. Apple Store, Cupertino, CA, USA) using the software Bellus3D (Inc. Campbell, CA, USA) in maximum intercuspation, with a full smile and with a scan reference device. After the scan procedure, a high-definition polygon file format (.ply) was exported, and linear measurements were collected with MeshLab (MeshLab; MeshLab). In order to further evaluate reference accuracy, a surface analysis was performed using a CAD software (GOM inspect, GOM). 3D deviations were calculated as root mean square. Statistical analysis was performed used two repeated-measures ANOVAs.
Results
: Results showed non-significant differences both for linear measurements (p=.22) and surface analysis (p=.58). Frontal references showed to be clinical reliable landmarks to be used during face scans alignment even with different facial expressions.
Conclusion
: The proposed technique seems to be suitable for the clinical use when superimposition of several face scans is required.
Clinical Significance
: This study showed the clinical reliability of face scans matching method using adhesives references that have low costs and are easy to use, allowing for a rapid registration of patient anatomy.
Technological developments have allowed a paradigm shift from manual and more classical dentistry practice to computer-assisted concepts and digital technologies use in daily practice. The integration of these technological systems in the field of implant dentistry should be patient-centered, effectiveness-focused, and evidence-based.
The hierarchical structure of research designs has become increasingly popular today, positioning designs in terms of their clinical relevance in which the level of evidence can be expressed through different systems,
For this purpose, studies in new emerging digital technologies should satisfy the fundamental standards of methodology, design, and data analysis to decrease the risk of research bias with systematic, random, or inferential errors.
The aim of this chapter is to review the most frequently adopted methods for evaluating digital technologies used in implant dentistry. Moreover, the different methodological designs used in vitro, in vivo, and clinical studies will be discussed, and guidelines proposed.
The treatment of edentulous or soon-to-be edentulous jaws requires surgical and prosthetic skill to achieve a functional outcome. These interventions have a profound impact on facial aesthetics with respect to support for the perioral tissues and lower face. Patients may present with significant loss of supporting tissue necessitating prosthetic replacement. Ideally, this intervention should be determined in the diagnostic phases to more predictably achieve the desired result and patient approval. Change in position of teeth and prosthetic contour can detrimentally affect speech. This chapter aims to provide a background to the effects of prosthesis contour and techniques to enhance aesthetics and maximise phonetic adaptation.KeywordsSpeechRestorative contoursPrototype
The use of three-dimensional (3D) facial scans for facial analysis is increasing in maxillofacial treatment. The aim of this study was to investigate the consistency of two-dimensional (2D) and 3D facial analyses performed by multiple raters. Six men and four women (25–36-year-old) participated in this study. The 2D images of the smiling and resting faces in the frontal and sagittal planes were obtained. The 3D facial and intraoral scans were merged to generate virtual 3D faces. Ten clinicians performed facial analyses by investigating 14 indices of 2D and 3D faces. Intra- and interrater agreements of the results of 2D and 3D facial analyses within and among the participants were evaluated. The intrarater agreement between the 2D and 3D facial analyses varied according to the indices. The highest and lowest agreements were found for the dental crowding index (0.94) and smile line curvature index (0.56) in the frontal plane, and Angle’s classification (canine) index (0.98) and occlusal plane angle index (0.55) in the profile plane. In the frontal plane, the interrater agreements were generally higher for the 3D images than for the 2D images, while in the profile plane, the interrater agreements were high in the Angle’s classification (canine) index however low in the other indices. Several occlusion-related indices were missing in the 2D images because the posterior teeth were not observed. Esthetic analysis results between 2D and 3D face images can differ according to the evaluation indices. The use of 3D faces is recommended over 2D images to increase the reliability of facial analyses, as it can fully assess both esthetic and occlusion-related indices.
Continuous innovation in digital dental technology offers new prospects for creating a complete virtual environment. This technique described adds a facial approach to the conventional digital workflow by incorporating 3D face scans to cone beam computed tomography and intraoral scans. Thus, obtaining a complete virtual patient for facially generated diagnostic wax up and planning to implement a predictable implant placement and interim prosthesis. It provides a full digital workflow by restoratively driven computer-aided implant planning, guided surgery, and 3D printing of an interim complete-arch fixed implant-supported prosthesis. This article is protected by copyright. All rights reserved.
Multimodal imaging, including 3D modalities, is increasingly being applied in orthodontics, both as a diagnostic tool and especially for the design of intraoral appliances, where geometric accuracy is very important. Laser scanners and other precision 3D-imaging devices are expensive and cumbersome, which limits their use in medical practice. Photogrammetry, using ordinary 2D photographs or video recordings to create 3D imagery, offers a cheaper and more convenient alternative, replacing the specialised equipment with handy consumer cameras. The present study addresses the question of to what extent, and under what conditions, this technique can be an adequate replacement for the 3D scanner. The accuracy of simple surface reconstruction and of model embedding achieved with photogrammetry was verified against that obtained with a triangulating laser scanner. To roughly evaluate the impact of image imperfections on photogrammetric reconstruction, the photographs for photogrammetry were taken under various lighting conditions and were used either raw or with a blur-simulating defocus. Video footage was also tested as another 2D-imaging modality feeding data into photogrammetry. The results show the significant potential of photogrammetric techniques.
Face scanners promise wide applications in medicine and dentistry, including facial recognition, capturing facial emotions, facial cosmetic planning and surgery, and maxillofacial rehabilitation. Higher accuracy improves the quality of the data recorded from the face scanner, which ultimately, will improve the outcome. Although there are various face scanners available on the market, there is no evidence of a suitable face scanner for practical applications. The aim of this in vitro study was to analyze the face scans obtained from four scanners; EinScan Pro (EP), EinScan Pro 2X Plus (EP+) (Shining 3D Tech. Co., Ltd. Hangzhou, China), iPhone X (IPX) (Apple Store, Cupertino, CA, USA), and Planmeca ProMax 3D Mid (PM) (Planmeca USA, Inc. IL, USA), and to compare scans obtained from various scanners with the control (measured from Vernier caliper). This should help to identify the appropriate scanner for face scanning. A master face model was created and printed from polylactic acid using the resolution of 200 microns on x, y, and z axes and designed in Rhinoceros 3D modeling software (Rhino, Robert McNeel and Associates for Windows, Washington DC, USA). The face models were 3D scanned with four scanners, five times, according to the manufacturer's recommendations; EinScan Pro (Shining 3D Tech. Co., Ltd. Hangzhou, China), EinScan Pro 2X Plus (Shining 3D Tech. Co., Ltd. Hangzhou, China) using Shining Software, iPhone X (Apple Store, Cupertino, CA, USA) using Bellus3D Face Application (Bellus3D, version 1.6.2, Bellus3D, Inc. Campbell, CA, USA), and Planmeca ProMax 3D Mid (PM) (Planmeca USA, Inc. IL, USA). Scan data files were saved as stereolithography (STL) files for the measurements. From the STL files, digital face models are created in the computer using Rhinoceros 3D modeling software (Rhino, Robert McNeel and Associates for Windows, Washington DC, USA). Various measurements were measured five times from the reference points in three axes (x, y, and z) using a digital Vernier caliper (VC) (Mitutoyo 150 mm Digital Caliper, Mitutoyo Co., Kanagawa, Japan), and the mean was calculated, which was used as the control. Measurements were measured on the digital face models of EP, EP+, IPX, and PM using Rhinoceros 3D modeling software (Rhino, Robert McNeel and Associates for Windows, Washington DC, USA). The descriptive statistics were done from SPSS version 20 (IBM Company, Chicago, USA). One-way ANOVA with post hoc using Scheffe was done to analyze the differences between the control and the scans (EP, EP+, IPX, and PM). The significance level was set at p = 0.05. EP+ showed the highest accuracy. EP showed medium accuracy and some lesser accuracy (accurate until 10 mm of length), but IPX and PM showed the least accuracy. EP+ showed accuracy in measuring the 2 mm of depth (diameter 6 mm). All other scanners (EP, IPX, and PM) showed less accuracy in measuring depth. Finally, the accuracy of an optical scan is dependent on the technology used by each scanner. It is recommended to use EP+ for face scanning.
Background:
The aim of this study was to compare accuracy and timing of two handheld, mobile three-dimensional surface imaging (3DSI) devices against an established non-portable medical imaging system, and to evaluate future intraoperative use for facial surgery.
Methods:
Surface-to-Surface root mean square analysis was used to evaluate both a consumer device (Sense 3D) and a professional surface scanner (Artec Eva) against a reference imaging system (Vectra XT). Two assessors repeatedly 3D-imaged the facial region of an imaging phantom and 30 volunteers in two separate sessions. Using both mobile devices, intraoperative 3DSI of 10 rhinoplasty patients was compared with preoperative reference imaging. Intraclass Correlation Coefficient was calculated for repeated measurements.
Results:
Artec Eva yielded mean deviations below 0.5 mm for the whole face and all subunits excluding the eye region. Sense 3D showed similar deviations for the whole face, but otherwise only in the central and lateral forehead unit and the medial cheek. Variability was low for both the non-portable Vectra XT and Artec Eva, whereas full-face assessment using Sense 3D resulted in high variability. When compared to the preoperative reference images, intraoperative rhinoplasty 3DSI revealed low deviations for Artec Eva and high deviations for Sense 3D.
Conclusions:
The 3D surfaces captured by Artec Eva showed a similarly desirable accuracy for facial imaging as Vectra XT reference images. This handheld device presents a suitable option for the objective documentation during rhinoplasty surgery. Sense 3D was unable to accurately capture complex facial surfaces and is therefore limited in its usefulness for intraoperative 3DSI.
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.
Purpose
The goal of this study was to assess the accuracy and reliability of a low-cost portable scanner (Scanify) for imaging facial casts compared to a previously validated portable digital stereophotogrammetry device (Vectra H1). This in vitro study was performed using 2 facial casts obtained by recording impressions of the authors, at King's College London Academic Centre of Reconstructive Science.
Materials and Methods
The casts were marked with anthropometric landmarks, then digitised using Scanify and Vectra H1. Computed tomography (CT) scans of the same casts were performed to verify the validation of Vectra H1. The 3-dimensional (3D) images acquired with each device were compared using linear measurements and 3D surface analysis software.
Results
Overall, 91% of the linear Scanify measurements were within 1 mm of the corresponding reference values. The mean overall surface difference between the Scanify and Vectra images was <0.3 mm. Significant differences were detected in depth measurements. Merging multiple Scanify images produced significantly greater registration error.
Conclusion
Scanify is a very low-cost device that could have clinical applications for facial imaging if imaging errors could be corrected by a future software update or hardware revision.
Purpose:
To evaluate the accuracy of a model made using the computer-aided design/computer-aided manufacture (CAD/CAM) milling method and 3D printing method and to confirm its applicability as a work model for dental prosthesis production.
Materials and methods:
First, a natural tooth model (ANA-4, Frasaco, Germany) was scanned using an oral scanner. The obtained scan data were then used as a CAD reference model (CRM), to produce a total of 10 models each, either using the milling method or the 3D printing method. The 20 models were then scanned using a desktop scanner and the CAD test model was formed. The accuracy of the two groups was compared using dedicated software to calculate the root mean square (RMS) value after superimposing CRM and CAD test model (CTM).
Results:
The RMS value (152±52 µm) of the model manufactured by the milling method was significantly higher than the RMS value (52±9 µm) of the model produced by the 3D printing method.
Conclusion:
The accuracy of the 3D printing method is superior to that of the milling method, but at present, both methods are limited in their application as a work model for prosthesis manufacture.
In this study, the practical accuracy (PA) of optical facial scanners for facial deformity patients in oral clinic was evaluated. Ten patients with a variety of facial deformities from oral clinical were included in the study. For each patient, a three-dimensional (3D) face model was acquired, via a high-accuracy industrial “line-laser” scanner (Faro), as the reference model and two test models were obtained, via a “stereophotography” (3dMD) and a “structured light” facial scanner (FaceScan) separately. Registration based on the iterative closest point (ICP) algorithm was executed to overlap the test models to reference models, and “3D error” as a new measurement indicator calculated by reverse engineering software (Geomagic Studio) was used to evaluate the 3D global and partial (upper, middle, and lower parts of face) PA of each facial scanner. The respective 3D accuracy of stereophotography and structured light facial scanners obtained for facial deformities was 0.58±0.11 mm and 0.57±0.07 mm. The 3D accuracy of different facial partitions was inconsistent; the middle face had the best performance. Although the PA of two facial scanners was lower than their nominal accuracy (NA), they all met the requirement for oral clinic use.
Background
The term "virtual patients" (VPs) has been used for many years in academic publications, but its meaning varies, leading to confusion. Our aim was to investigate and categorize the use of the term "virtual patient" and then classify its use in healthcare education. Methods: A literature review was conducted to determine all articles using the term "virtual patient" in the title or abstract. These articles were categorized into: Education, Clinical Procedures, Clinical Research and E-Health. All educational articles were further classified based on a framework published by Talbot et al. which was further developed using a deductive content analysis approach. Results: 536 articles published between 1991 and December 2013 were included in the study. From these, 330 were categorized as educational. Classifying these showed that 37% articles used VPs in the form of Interactive Patient Scenarios. VPs in form of High Fidelity Software Simulations (19%) and Virtual Standardized Patients (16%) were also frequent. Less frequent were other forms, such as VP Games.Analyzing the literature across time shows an overall trend towards the use of Interactive Patient Scenarios as the predominant form of VPs in healthcare education. Conclusions: The main form of educational VPs in the literature are Interactive Patient Scenarios despite rapid technical advances that would support more complex applications. The adapted classification provides a valuable model for VP developers and researchers in healthcare education to more clearly communicate the type of VP they are addressing avoiding misunderstandings.
PURPOSE:
The three-dimensional morphological analysis of facial expressions has been becoming increasingly common and hand-held three-dimensional scanners can be advantageous in data acquisition due to their mobility. The aim of the present study was to test intra-subject, intra-observer and inter-observer reproducibility and reliability of a hand-held scanner during facial expressions.
MATERIALS AND METHODS:
In order to investigate intra-subject reproducibility and reliability, we performed face scanning two times on 30 healthy subjects at three-month intervals. In addition, two observers scanned twice the face of 10 healthy subjects consecutively to evaluate intra-observer and inter-observer differences. Scannings were performed during facial expressions. Face asymmetry and severity of facial expression were determined using root mean square (RMS) value. Repeated-measurement ANOVA was used to test the reproducibility and correlation coefficient to determine the reliability of the facial expressions.
RESULTS:
The mean RMS values measured at different times were not significantly different for any facial expression (p > 0.05). The reliability of the measurements was variable depending on the facial expression (r = 0.47 and 0.98, p < 0.05).
CONCLUSIONS:
Our study may contribute to the development of new techniques for examining facial expressions. Hereby, morphological analysis may be possible in the clinic and at the bedside without the need for laboratory conditions.
KEYWORDS:
Asymmetry; Face morphology; Facial expression; Handheld scanner; Intensity
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.
Objective
Comparison of soft tissue replication between conventional and digital impressions for definitive single unit implant rehabilitation in the esthetic zone.
Materials and Methods
Six patients were recruited according to inclusion criteria for this cross‐over pilot study and submitted to a conventional silicone implant impression with customized coping and a digital impression with an intraoral scanner. Stereolithography files obtained from the same patient were superimposed with appropriate software and trueness evaluated between methods at predetermined locations (56 in hard and soft tissues and 18 in the emergence profile, per patient). Results were presented as mean root mean square (RMS) ± 95% confidence interval and effect size calculated with Hedges' g ± 95%. Mann‐Whitney and Kruskal‐Wallis were performed when appropriate and α was set at .05.
Results
Trueness between methods equated to 51.08[45.68;56.47] μm and 60.46[52.29;68.62] μm in hard and soft tissues, respectively. Soft tissue replication by intraoral scanner acquisition corresponded to a statistically significant RMS of 243.89[209.15;278.63] μm equating to a Hedges' g of 1.52[1.22;1.82] which corresponded to a large effect size.
Conclusions
The proposed method could be considered for soft tissues assessment and the results suggest that intraoral impression techniques produce statistically significant changes in peri‐implant soft tissue replication, although below the clinically detectable threshold.
Clinical Significance
The proposed technique allows for the 3D determination of peri‐implant tissues changes in digital models with higher sensitivity than visual techniques, thus presenting itself as a promising alternative in clinical studies and that the use of an intraoral scanner obtained significant differences in the soft tissue emergence profile replication when compared with the gold standard.
Statement of problem. Three-dimensional visualization for pretreatment diagnostics and treat- 77 ment planning is necessary for surgical and prosthetic rehabilitations. The reliability of a novel 3D 78 facial camera is unclear. 79
Purpose. The purpose of this clinical study was to evaluate the reliability of a novel medical facial 80 camera system in capturing the 3D geometry of the face in a single exposure. 81
Material and methods. Twelve edentulous participants (7 women and 5 men; mean age: 74.6 82 years) were included, and digital images for facial reconstruction were captured using a 83 custom-made static capturing system (Medusa Static; Disney Research Zurich). Eight extraoral 84 soft-tissue facial landmarks were identified, which included the right outer canthus (OCR), left 85 outer canthus (OCL), right cheilion (CmR), left cheilion (CmL), pronasale nostril tip, subnasale, 86 philtrum, and gnathion (GN). Interlandmark distances of OCR-OCL, OCR-CmR, OCL-CmL, OCR-GN, 87 OCL-GN, CmR-CmL, pronasale nostril tipeGN, and subnasale-GN were measured clinically and 88 then on the 3D digital reconstructions. The absolute differences between the digital and clinical 89 measurements were recorded. The intraclass correlation coefficient was applied to evaluate the reliability of digital measurement and interexaminer reliability. 90
Results. The mean ±standard deviation difference between the clinical and digital measurements 91 was 1.95 ±0.33 mm. Intraclass correlation coefficients computed for the 2 examiners against clinical 92 measurements were all above 0.5. The interexaminer reliability coefficient of digital measurement 93 was above 0.909. 94
Conclusions. The 3D facial geometry obtained from the novel medical facial camera system was 95 found to be reliable and clinically acceptable. Inconsistencies in measurements for a few specific 96 facial landmarks may arise, but these can be avoided by thorough examiner calibration before 97 undertaking the digital measurements.
Purpose:
A prospective study was performed to test the accuracy and reproducibility of the DAVID-SLS-2 scanner (SLS-2) [DAVID Vision Systems GmbH], compared to the validated 3dMDtrio scanner (3dMD) [3dMD, LLC, Atlanta, GA, USA].
Materials and methods:
The accuracy of the SLS-2 was determined through multiple scans of a mannequin face model using both scanners. The reproducibility of a protocol for achieving consistent three-dimensional (3D) face scans in live subjects was carried out using the SLS-2. A precision of ≤1 mm was considered clinically significant.
Results:
The mannequin face model was reproduced with no significant errors in the SLS-2 compared to the 3dMDtrio, with normally distributed data (mean = 0.002 mm; SD = 0.01 mm). In live subjects, the forehead, midface, chin and general face region showed mean errors and SD <0.24 mm and <1 mm, respectively. In the neck area, the data were not found to be normally distributed (mean = -1.6 mm; SD = 2.1 mm).
Conclusion:
Structured light scanning may be used for acquiring 3D face scans in live subjects in a radiation-free and reproducible manner, provided that the head of the subject is positioned in the same posture for each scan. Special care is recommended in positioning the head in the sagittal plane during scanning.
The aim of this Short Communication was to present a workflow for the superimposition of intraoral scan (IOS), cone-beam computed tomography (CBCT), and extraoral face scan (EOS) creating a 3D virtual dental patient.
As a proof-of-principle, full arch IOS, preoperative CBCT, and mimic EOS were taken and superimposed to a unique 3D data pool. The connecting link between the different files was to detect existing teeth as constant landmarks in all three data sets.
This novel application technique successfully demonstrated the feasibility of building a craniofacial virtual model by image fusion of IOS, CBCT, and EOS under 3D static conditions.
The presented application is the first approach that realized the fusion of intraoral and facial surfaces combined with skeletal anatomy imaging. This novel 3D superimposition technique allowed the simulation of treatment planning, the exploration of the patients' expectations, and the implementation as an effective communication tool. The next step will be the development of a real-time 4D virtual patient in motion.
In this work, we compared accuracy, repeatability, and usability in breast surface imaging of 2 commercial surface scanning systems and a hand-held laser surface scanner prototype coupled with a patient's motion acquisition and compensation methodology. The accuracy of the scanners was assessed on an anthropomorphic phantom, and to evaluate the usability of the scanners on humans, thorax surface images of 3 volunteers were acquired. Both the intrascanner repeatability and the interscanner comparative accuracy were assessed. The results showed surface-to-surface distance errors inferior to 1 mm and to 2 mm, respectively, for the 2 commercial scanners and for the prototypical one. Moreover, comparable performances of the 3 scanners were found when used for acquiring the breast surface. On the whole, this study demonstrated that handheld laser surface scanners coupled with subject motion compensation methods lend themselves as competitive technologies for human body surface modeling.
The aim of our study was to develop a reliable method to identify certain facial expressions of the lower face that are easy to re-create through proper instruction and with high reproducibility. We wanted to quantitatively evaluate facial expressions in a simple, efficient, and inexpensive manner that is easily applicable in many clinical settings and in a wide variety of patients.
We included 40 healthy subjects (20 women [mean age, 25.6 years] and 20 men [mean age, 27.0 years]). A digital camcorder recorded a video sequence (video 1) where the subject was verbally asked to execute several facial expressions (posed smile, spontaneous smile, aggressive smile, lip pucker, and maximum opening). Two weeks later, the video session was repeated (video 2). Frames of each expression were selected from the digitized video sequences. Horizontal and vertical distances were measured in each selected frame.
We found no statistically significant differences between the 2 videos of the expressions studied (except vertical lip changes for posed smile, lip pucker, and maximum mouth opening expression). The calculated coefficient of reliability was high and varied between 0.994 and 0.996, which confirms the reliability of the method.
This 2-dimensional method is an accurate means to quantitatively evaluate facial expressions in a simple, efficient, and inexpensive manner. The lip pucker, posed smile, spontaneous smile, and aggressive smile were the best and most reproducible expressions of the chosen expressions in this study.
In 3D photographs the bony structures are neither available nor palpable, therefore, the bone-related landmarks, such as the soft tissue gonion, need to be redefined. The purpose of this study was to determine the reproducibility and reliability of 49 soft tissue landmarks, including newly defined 3D bone-related soft tissue landmarks with the use of 3D stereophotogrammetric images. Two observers carried out soft-tissue analysis on 3D photographs twice for 20 patients. A reference frame and 49 landmarks were identified on each 3D photograph. Paired Student's t-test was used to test the reproducibility and Pearson's correlation coefficient to determine the reliability of the landmark identification. Intra- and interobserver reproducibility of the landmarks were high. The study showed a high reliability coefficient for intraobserver (0.97 (0.90 - 0.99)) and interobserver reliability (0.94 (0.69 - 0.99)). Identification of the landmarks in the midline was more precise than identification of the paired landmarks. In conclusion, the redefinition of bone-related soft tissue 3D landmarks in combination with the 3D photograph reference system resulted in an accurate and reliable 3D photograph based soft tissue analysis. This shows that hard tissue data are not needed to perform accurate soft tissue analysis.
The three-dimensional (3D) measuring technology is useful to inspect facial shape in three planes of space (X, Y, and Z). Recent work has been directed to analyse craniofacial morphology using facial soft tissue landmarks to identify facial differences among population. The reproducibility of facial landmarks is almost necessary to ensure accurate 3D facial measurements.
The aim of this study is to assess the reproducibility of facial soft tissue landmarks using laser-scan 3D imaging technology.
Facial landmarks were assessed for 30 15(1/2)-year-old British-Caucasian children (15 males and 15 females). The sample was recruited from the Avon Longitudinal Study of Parents and Children (ALSPAC). The 3D facial images were acquired for each subject using two high-resolution Konica/Minolta laser scanners. Twenty-one facial landmarks (63 X, Y, and Z coordinates) were identified and recorded on each 3D facial image by two examiners. The reproducibility of landmarks identification at 2-week interval was assessed for one of the examiners (intra-examiner). In addition, the reproducibility of landmarks was assessed between the two examiners (inter-examiner). Using Bland-Altman plots, both intra- and inter-examiner assessments had evaluated landmarks reproducibility in three dimensions for the sample divided by gender. The reproducibility of the 3D-coordinates for each landmark was considered under three categories (< 0.5 mm, < 1 mm, and >1 mm) for both intra- and inter-examiner reproducibility assessments.
The distribution of coordinates at the three levels of reproducibility show the following percentages: intra-examiner: < 0.5 mm (38%), < 1 mm (51%), >1 mm (11%); inter-examiner: < 0.5 mm (35%), < 1 mm (48%), >1 mm (17%). Generally, 10 landmarks were reproducible to less than 1 mm for both intra- and inter-examiner reproducibility assessments. The Labiale Superius was the most reproducible and Palebrale Superius was the least reproducible landmark. Some landmarks showed greater reliability in certain planes of space; the Glabella was more reliable in the Z than the Y axis. Gender differences were found; Subnasale was more reproducible in the Y-axis in males compared with females.
The reproducibility of facial landmarks should be considered in the three planes of space. The majority of X-Y-Z coordinates taken to the 21 facial landmarks were reproducible to < 1 mm which is clinically acceptable. The accuracy of landmarks identification ranged from 0.39 to 1.49 mm. The reliability in identification depends on the clarity and definition of each landmark as well as gender characteristics. The different landmarks reproducibility should be considered when evaluating changes related to growth and healthcare interventions.
Intuitive Facial Imaging Method for Evaluation of Postoperative Swelling: A Combination of 3-This peer-reviewed, accepted manuscript will undergo final editing and production prior to publication in IJP
- S Yamamoto
- H Miyachi
- H Fujii
- S Ochiai
- S Watanabe
- K Shimozato
Yamamoto S, Miyachi H, Fujii H, Ochiai S, Watanabe S, Shimozato K. Intuitive
Facial Imaging Method for Evaluation of Postoperative Swelling: A Combination of 3-This peer-reviewed, accepted manuscript will undergo final editing and production prior to publication in IJP.
Validity and reliability of a Portuguese version of the Summated Xerostomia Inventory-5
- J Amaral
- D Marques
- W M Thomson
- Arr Vinagre
- A Da Mata
Amaral J, Marques D, Thomson WM, Vinagre ARR, da Mata A. Validity and
reliability of a Portuguese version of the Summated Xerostomia Inventory-5.
Gerodontology. 2018;35(1):33-37.