Face Scanning Research Articles

Comparative analysis of 3D tomography based soft tissue rendering and Proface facial scanning systems in orthognathic surgery

PurposeThis study aimed to investigate the linear and angular differences in the nasolabial soft tissue in patients who underwent bimaxillary orthognathic surgery using two different three-dimensional imaging methods. Furthermore, the advantages, disadvantages, and limitations of these methods were determined after comparing the data obtained from the imaging methods used in the study. Materials and MethodsPreoperative (T0) and 6-months postoperative (T1) cone-beam computed tomography (CBCT) and three-dimensional facial scanning (3DFS) data from 22 patients who underwent maxillary advancement surgery were examined. The DICOM (Digital Imaging and Communications in Medicine) data (CBCT group) and “.obj” format images (3DFS group) of the patients were analyzed using Dolphin software (Dolphin Imaging®, Version 12, Chatsworth, CA, USA). The linear and angular soft tissue measurements were calculated after determining the reference anatomical landmarks for both groups. ResultsMeasurements with CBCT and 3DFS imaging methods were compared at T0, T1, and all measurements (T0+T1). No statistically significant difference was observed between the CBCT and 3DFS groups for five measurements performed at T0 and T0+T1, but statistically significant differences were observed between the groups for the other seven measurements. There was no statistically significant difference between the CBCT and 3DFS groups for six measurements at T1, but there were statistically significant differences between the groups for the other six measurements. After reviewing the postoperative differences in the nasolabial soft tissue, a statistically significant increase in four linear and one angular measurement in the 3DFS group was observed, and there was a statistically significant increase in two linear and two angular measurements in the CBCT group. Upon comparison of postoperative differences in soft tissue alterations, no statistically significant difference between the 3DFS group and the CBCT group were observed in any of the soft tissue measurements. ConclusionOrthognathic surgery has significant effects on nose width and upper lip morphology. Although both 3DFS and CBCT methods can be used to evaluate such effects, the results of the present study revealed differences in sensitivity and limitations between the two methods. Thus, surgical outcomes should be evaluated in consideration of the abovementioned parameters.

Effects of wax rim in image registration of intraoral and face scan in edentulous arch condition

Effects of wax rim in image registration of intraoral and face scan in edentulous arch condition

Network analysis of three-dimensional hard-soft tissue relationships in the lower 1/3 of the face: skeletal Class I-normodivergent malocclusion versus Class II-hyperdivergent malocclusion

BackgroundThe determining effect of facial hard tissues on soft tissue morphology in orthodontic patients has yet to be explained. The aim of this study was to clarify the hard-soft tissue relationships of the lower 1/3 of the face in skeletal Class II-hyperdivergent patients compared with those in Class I-normodivergent patients using network analysis.MethodsFifty-two adult patients (42 females, 10 males; age, 26.58 ± 5.80 years) were divided into two groups: Group 1, 25 subjects, skeletal Class I normodivergent pattern with straight profile; Group 2, 27 subjects, skeletal Class II hyperdivergent pattern with convex profile. Pretreatment cone-beam computed tomography and three-dimensional facial scans were taken and superimposed, on which landmarks were identified manually, and their coordinate values were used for network analysis.Results(1) In sagittal direction, Group 2 correlations were generally weaker than Group 1. In both the vertical and sagittal directions of Group 1, the most influential hard tissue landmarks to soft tissues were located between the level of cemento-enamel junction of upper teeth and root apex of lower teeth. In Group 2, the hard tissue landmarks with the greatest influence in vertical direction were distributed more forward and downward than in Group 1. (2) In Group 1, all the correlations for vertical-hard tissue to sagittal-soft tissue position and sagittal-hard tissue to vertical-soft tissue position were positive. However, Group 2 correlations between vertical-hard tissue and sagittal-soft tissue positions were mostly negative. Between sagittal-hard tissue and vertical-soft tissue positions, Group 2 correlations were negative for mandible, and were positive for maxilla and teeth.ConclusionCompared with Class I normodivergent patients with straight profile, Class II hyperdivergent patients with convex profile had more variations in soft tissue morphology in sagittal direction. In vertical direction, the most relevant hard tissue landmarks on which soft tissue predictions should be based were distributed more forward and downward in Class II hyperdivergent patients with convex profile. Class II hyperdivergent pattern with convex profile was an imbalanced phenotype concerning sagittal and vertical positions of maxillofacial hard and soft tissues.

Neural network auto-segmentation of serial-block-face scanning electron microscopy images exhibit collagen fibril structural differences with tendon type and health.

A U-Net machine learning algorithm was adapted to automatically segment tendon collagen fibril cross-sections from serial block face scanning electron microscopy (SBF-SEM) and create three-dimensional (3D) renderings. We compared the performance of routine Otsu thresholding and U-Net for a positional tendon that has low fibril density (rat tail tendon), an energy-storing tendon that has high fibril density (rat plantaris tendon), and a high fibril density tendon hypothesized to have disorganized 3D ultrastructure (degenerated rat plantaris tendon). The area segmentation of the tail and healthy plantaris tendon had excellent accuracy for both the Otsu and U-Net, with an Intersection over Union (IoU) of 0.8. With degeneration, only the U-Net could accurately segment the area, whereas Otsu IoU was only 0.45. For boundary validation, the U-Net outperformed Otsu segmentation for all tendons. The fibril diameter from U-Net was within 10% of the manual segmentation, however, the Otsu underestimated the fibril diameter by 39% in healthy plantaris and by 84% in the degenerated plantaris. Fibril geometry was averaged across the entire image stack and compared across tendon types. The tail had a lower fibril area fraction (58%) and larger fibril diameter (0.31 µm) than the healthy plantaris (67% and 0.21 µm) and degenerated plantaris tendon (66% and 0.19 µm). This method can be applied to a large variety of tissues to quantify 3D collagen fibril structure.

Measuring the esthetic outcome using a three-dimensional facial scanner after parotidectomy and application of vascularized fat flaps

BackgroundParotidectomy can affect facial symmetry. Our study evaluated the symmetry of different facial areas and upper neck after total parotidectomy and filling the area with vascularized fat flap (VFF). MethodsFacial symmetry was evaluated in eight patients and a control group matched in terms of gender and age, using a three-dimensional (3D) facial scanner. The operated side was compared with the non-operated side and the symmetry compared with that of the control group. Scanning was performed either within the first year (group 1; n = 5) or after 3 years (group 2; n = 3) postoperatively. ResultsThe patients’ cheek and neck areas were found to be significantly more asymmetric, but the cheek area in group 2 was significantly more symmetrical when compared with group 1. ConclusionVFF appeared to achieve similar facial symmetry to the matched non-operated group. Time had a positive impact on the facial symmetry. The neck area was the most asymmetric, and proved to be unreliable, regardless of whether any procedure was performed or not.

Using three-dimensional geometric morphometry for facial analysis in patients with the oculo-auriculo-vertebral spectrum.

To utilize three-dimensional (3D) geometric morphometry for visualization of the level of facial asymmetry in patients with the oculo-auriculo-vertebral spectrum (OAVS). Three-dimensional facial scans of 25 Czech patients with OAVS were processed. The patients were divided into subgroups according to Pruzansky classification. For 13 of them, second 3D facial scans were obtained. The 3D facial scans were processed using geometric morphometry. Soft tissue facial asymmetry in the sagittal plane and its changes in two time spots were visualized using colour-coded maps with a thermometre-like scale. Individual facial asymmetry was visualized in all patients as well as the mean facial asymmetry for every Pruzansky subgroup. The mean colour-coded maps of type I and type IIA subgroups showed no differences in facial asymmetry, more pronounced asymmetry in the middle and the lower facial third was found between type IIA and type IIB (maximum 1.5 mm) and between type IIB and type III (maximum 2 mm). The degree of intensity facial asymmetry in affected middle and lower facial thirds did not change distinctly during the two time spots in all subgroups. The 3D geometric morphometry in OAVS patients could be a useful tool for objective facial asymmetry assessment in patients with OAVS. The calculated colour-coded maps are illustrative and useful for clinical evaluation.

Learning a Generalized Physical Face Model From Data

Physically-based simulation is a powerful approach for 3D facial animation as the resulting deformations are governed by physical constraints, allowing to easily resolve self-collisions, respond to external forces and perform realistic anatomy edits. Today's methods are data-driven, where the actuations for finite elements are inferred from captured skin geometry. Unfortunately, these approaches have not been widely adopted due to the complexity of initializing the material space and learning the deformation model for each character separately, which often requires a skilled artist followed by lengthy network training. In this work, we aim to make physics-based facial animation more accessible by proposing a generalized physical face model that we learn from a large 3D face dataset. Once trained, our model can be quickly fit to any unseen identity and produce a ready-to-animate physical face model automatically. Fitting is as easy as providing a single 3D face scan, or even a single face image. After fitting, we offer intuitive animation controls, as well as the ability to retarget animations across characters. All the while, the resulting animations allow for physical effects like collision avoidance, gravity, paralysis, bone reshaping and more.

Digital-assisted multidisciplinary treatment for complex occlusal rehabilitation: an 18-month follow-up case report

BackgroundThis case report highlights the importance of standardized and fully digital sequential treatment in complex occlusal rehabilitation cases. To fully resolve the patient’s dental needs, such cases often require multidisciplinary interventions including periodontal therapy, endodontic treatment, anterior esthetics, implant restoration, and prosthetic rehabilitation. A fully digital workflow (including facial scanners, intraoral scanners, jaw motion tracking systems, virtual articulators, and computer-aided design software) streamlined the complex treatment, enhancing workflow simplicity, efficiency, visibility, and precision.Case presentationThe patient presented with decreased chewing efficiency of the upper and lower prostheses, along with unsatisfactory esthetic appearance of the anterior teeth. After physical examination and radiological assessment, this complex occlusal rehabilitation case required periodontal therapy, anterior esthetic enhancement, implant restoration, and fixed prosthetic rehabilitation. Therefore, a fully digital workflow was adopted. Full-crown prostheses were placed on teeth 13, 23, and 34; a fixed bridge encompassed positions 32 to 42, and single implant crowns were placed on teeth 35 and 36. Implant-supported fixed bridges were constructed for teeth 12 to 22 and 44 to 46, anchored by implants at teeth 12, 22, 44, and 46. All definitive prostheses were fabricated from zirconia ceramics, chosen for their durability and esthetic characteristics. Finally, restorations with satisfactory esthetic and functional characteristics were seated, preserving the tooth and its supporting structures. During treatment and follow-up, the T-scan occlusal analysis system was utilized to continuously monitor and guide the adjustment of occlusal distribution across the patient’s dental arches. After 18 months, the patient remains satisfied with the definitive restorations.ConclusionsThis report is intended to help dentists understand and implement standardized and fully digital workflows during the management of complex occlusal rehabilitation cases; it may also facilitate harmonious integration of esthetic and functional characteristics.

Idiosyncratic fixation patterns generalize across dynamic and static facial expression recognition

Facial expression recognition (FER) is crucial for understanding the emotional state of others during human social interactions. It has been assumed that humans share universal visual sampling strategies to achieve this task. However, recent studies in face identification have revealed striking idiosyncratic fixation patterns, questioning the universality of face processing. More importantly, very little is known about whether such idiosyncrasies extend to the biological relevant recognition of static and dynamic facial expressions of emotion (FEEs). To clarify this issue, we tracked observers’ eye movements categorizing static and ecologically valid dynamic faces displaying the six basic FEEs, all normalized for time presentation (1 s), contrast and global luminance across exposure time. We then used robust data-driven analyses combining statistical fixation maps with hidden Markov Models to explore eye-movements across FEEs and stimulus modalities. Our data revealed three spatially and temporally distinct equally occurring face scanning strategies during FER. Crucially, such visual sampling strategies were mostly comparably effective in FER and highly consistent across FEEs and modalities. Our findings show that spatiotemporal idiosyncratic gaze strategies also occur for the biologically relevant recognition of FEEs, further questioning the universality of FER and, more generally, face processing.

Intraoral scanner-based virtual facebow transferring: A chairside dental technique.

Accurately mounting dental casts on an articulator is an essential step in prosthetic treatments. In digital dentistry, virtual articulator mounting procedures rely on virtual facebow records. However, virtual facebow records usually require devices like face scanners or jaw motion tracking systems that are not commonly available in most dental practices. The present technique report describes a straightforward intraoral scanner-based virtual facebow transfer approach. In this technique, a reference facebow joint support was first scanned and aligned with a virtual articulator. Then, a patient's facebow joint support and bite fork assembly were scanned chairside with an intraoral scanner and aligned with the virtual articulator by matching common features with the reference facebow joint support. After aligning the patient's intraoral scans with the patient's bite fork scan that was already superimposed on the virtual articulator, a virtual mounting process was achieved. Once the corresponding reference facebow joint supports have been generated, this technique can be easily implemented with most facebow systems and be seamlessly integrated into daily clinical practice as only an intraoral scanner and a conventional facebow were required.

Stereophotometric facial changes in edentulous older adults after rehabilitation with complete dentures.

To evaluate the facial characteristics of edentulous older adults who underwent rehabilitation using complete dentures, and to compare them with dentate individuals. Edentulism rehabilitation with complete dentures aims to restore occlusion and facial aesthetics. The study included 102 edentulous participants needing prosthodontic rehabilitation with complete dentures and 30 with a natural dentition (aged >65). The 3D facial scans were performed using an Artec optical scanner. Superficial facial landmarks were identified, and 16 parameters were calculated. Regional analysis with the superimposition of two scans was used to calculate the average distances and percentage of non-matching surfaces in the 11 regions. Paired and independent t-tests (α = .05) were used to test for group differences, as appropriate. After rehabilitation with complete dentures, facial changes were most noticeable in the perioral region: wider rima oris, longer upper lip, wider upper vermilion, and more protruded profile. The comparison of facial regions without and with dentures showed fuller and curvier cheeks, with no direct influence of dentures. The edentulous faces with dentures appeared shorter and more retruded than those of dentate individuals. A narrower lower vermilion, retruded upper lip, and more flattened facial profile were observed in females with dentures than in their dentate peers. Besides the expected positive influence of rehabilitation with complete dentures on facial appearance in the perioral region, there are some unexpected changes, such as fuller cheeks, but there is still deficiency in vertical facial dimensions and a more flattened facial profile.

COMPUTER PRODUCTION OF FACIAL EPITHETS

BACKGROUND: The issue of rehabilitation of patients with facial defects is extremely acute. In addition to the annual increase in the number of patients with cancer of the maxillofacial region, in recent years the number of people with shrapnel and gunshot wounds to the face has increased as a result of local wars and conflicts. Traditional methods of orthopedic rehabilitation of patients and the manufacture of facial epitheses are quite a complex and lengthy process. In the postoperative period, there is a sharp decrease in the quality of life of this category of patients, a violation of the basic body functions necessary for vital activity and poor social adaptation. Direct prosthetics of the face in the postoperative period was impossible due to the lack of necessary digital modeling technologies and structural materials for additive or subtractive production methods. The production of temporary or permanent facial epitheses using digital technologies is an urgent task that can improve the social and functional living conditions of patients. AIMS: Development of 3D modeling technology for additive manufacturing of facial epithets. METHODS: To achieve this goal, the first task was to develop specialized three-dimensional software for modeling defects in the facial area. The functionality of the program should allow you to virtually simulate the missing parts of the face (ear, eye, nose, orbit). To create a digital platform together with IT specialists, it was decided to use the following programming languages: C++ - Writing the software core, writing UI/UX interaction modules, interacting with the Windows operating system; C# - Complex assembly of the entire project; Python is an automated assembly of virtual library modules; OpenGL HSLS is a shader language for graphical visualization of objects; C is the creation of functions for interacting with shaders that require high speed. RESULTS: A specialized computer program has been developed for 3D modeling of prostheses in patients with defects in the middle zone of the face using combined facial scanning and computed tomography data (Computer program. Apresyan S.V., Stepanov A.G. "A program for 3D modeling of facial epitheses. Registration number (certificate) 2023663490, Registration date: 07/04/2023). Instead of obtaining analog impressions with plaster or silicone material, the developed technology uses a special 3D facial scanner, which greatly eases the suffering of patients. A virtual three-dimensional database of ears, noses, orbits, and zygomatic bones of patients of various ages and gender is integrated into the developed program. This allows the specialist to select the most adaptive part of the face to make up for the defect. Built-in modeling tools allow you to personalize a 3D model of a part of the face, based on the structural features of the maxillofacial region of a person. The finished three-dimensional model of a part of the face can be exported in various formats CONCLUSIONS: The developed 3D program for modeling defects allows to avoid invasive prosthetics approaches, to coordinate the shape of future structures with the patient. The built-in library of structures with a database provides remote manufacturing of the prosthesis without the presence of the patient, in case of a need to replace it. Among the undeniable advantages of the technology, it is important to include the fact that prostheses can be made directly on the day of surgery to remove part of the face, completely restoring lost functions and providing rapid social adaptation.

Nanostructured Implant-Tissue Interface Assessment Using a Three-Dimensional Gingival Tissue Equivalent.

Improved soft tissue integration (STI) around dental implants is key for implant success. The formation of an early and long-lasting transmucosal seal around the implant abutment might help to prevent peri-implantitis, one of the major causes of late implant failure. In natural teeth, collagen fibers are firmly inserted and fixed in the cementum of the tooth and emerge perpendicular to the gingival tissue. In contrast, around dental implants, collagen fibers run predominantly parallel to the implant surface, allowing bacterial migration into the peri-implant interface that might lead to peri-implantitis. Previous studies have shown that nanostructured Ti surfaces improve gingival cell response in monolayer cell cultures. Here, we aimed at evaluating the implant-tissue interface using a 3D gingival tissue equivalent (GTE). First, we evaluated the GTE response to a nanostructured (NN) and machined Ti surface after the stimulation with Porphyromonas gingivalis lipopolysaccharide (LPS), to simulate peri-implantitis conditions. Thus, GTE viability, through MTT assay, the release of metalloproteinase-1 (MMP1) and its inhibitor (TIMP1) through ELISA, and the gene expression of extracellular matrix turnover genes by real-time RT-PCR were analyzed. Second, GTE-implant interaction was characterized by serial block face scanning electron microscopy, and collagen-1 orientation at the tissue-implant interface was analyzed by immunofluorescence. While a similar GTE response to LPS stimulation was found for both implant surfaces, a higher proportion of collagen oriented perpendicular to the implant was observed on the NN implant surface. Thus, our results indicate that the nanostructuration of titanium dental implant abutments could allow the correct orientation of collagen fibers and greater soft tissue sealing, while keeping biocompatibility levels and LPS response comparable.

Validity and Reliability of New Three-Dimensional Reference Systems for Soft Tissue Analysis Using Non-Ionizing Three-Dimensional Imaging

Background: The aim of this study was to evaluate the accuracy and the repeatability of two reference systems for three-dimensional facial scans (FSs) compared with a reference system based on cone-beam computed tomography (CBCT). Subjects and methods: A total of sixty subjects, thirty growing participants (8–17 years old) and thirty non-growing participants (older than 21 years old), with FSs and full-field-of-view CBCT were included. Two different reference systems on the same FS were constructed. To assess validity, the two reference systems based on FSs were compared with the reference systems built using the CBCT scans. After two weeks, all of the FSs were reassessed to evaluate intra-operator repeatability. Reliability and repeatability were evaluated by means of parametric and non-parametric tests, intra-class correlation, the Dahlberg formula, and Bland–Altman plots (p < 0.05). Results: Both reference systems presented good reliability and showed a small difference with respect to the CBCT-based sagittal plane (Sagittal FS1 = 1.90 ± 0.98°; Sagittal FS2 = 1.80 ± 1.13°; p = 0.232). Between them, the two reference systems showed a small difference in the position of the sagittal plane (Sagittal FS1^Sagittal FS2 = 1.39 ± 1.13°). Conclusions: Both reference systems assessed in this study showed good intra-operator repeatability and their use may be suggested as reliable reference systems for FSs.

From masks to muscles: Mapping facial structure of Nycticebus.

Facial musculature in mammals underlies mastication and nonverbal communicative facial displays. Our understanding of primate facial expression comes primarily from haplorrhines (monkeys and apes), while our understanding of strepsirrhine (lemurs and lorises) facial expression remains incomplete. We examined the facial muscles of six specimens from three Nycticebus species (Nycticebus coucang, Nycticebus javanicus, and Nycticebus menagensis) using traditional dissection methodology and novel three-dimensional facial scanning to produce a detailed facial muscle map, and compared these results to another nocturnal strepsirrhine genus, the greater bushbaby (Otolemur spp.). We observed 19 muscles with no differences among Nycticebus specimens. A total of 17 muscles were observed in both Nycticebus and Otolemur, with little difference in attachment and function but some difference in directionality of movement. In the oral region, we note the presence of the depressor anguli oris, which has been reported in other primate species but is absent in Otolemur. The remaining muscle is a previously undescribed constrictor nasalis muscle located on the lateral nasal alar region, likely responsible for constriction of the nares. We propose this newly described muscle may relate to vomeronasal organ functioning and the importance of the use of nasal musculature in olfactory communication. We discuss how this combined methodology enabled imaging of small complex muscles. We further discuss how the facial anatomy of Nycticebus spp. relates to their unique physiology and behavioral ecology.

Smartphone applications for facial scanning: A technical and scoping review.

Facial scanning through smartphone scanning applications (SSA) is increasingly being used for medical applications as cost-effective, chairside method. However, clinical validation is lacking. This review aims to address: (1) Which SSA could perform facial scanning? (2) Which SSA can be clinically used? (3) Which SSA have been reported and scientifically validated for medical applications? Technical search for SSA designed for face or object scanning was conducted on Google, Apple App Store, and Google Play Store from August 2022 to December 2023. Literature search was performed on PubMed, Cochrane, EMBASE, MEDLINE, Scopus, IEEE Xplore, ACM Digital Library, Clinicaltrials.gov, ICTRP (WHO) and preprints up to 2023. Eligibility criteria included English-written scientific articles incorporating at least one SSA for clinical purposes. SSA selection and data extraction were executed by one reviewer, validated by second, with third reviewer being consulted for discordances. Sixty-three applications designed for three-dimensional object scanning were retrieved, with 52 currently offering facial scanning capabilities. Fifty-six scientific articles, comprising two case reports, 16 proof-of-concepts and 38 experimental studies were analysed. Thirteen applications (123D Catch, 3D Creator, Bellus 3D Dental Pro, Bellus 3D Face app, Bellus 3D Face Maker, Capture, Heges, Metascan, Polycam, Scandy Pro, Scaniverse, Tap tap tap and Trnio) were reported in literature for digital workflow integration, comparison or proof-of-concept studies. Fifty-two SSA can perform facial scanning currently and can be used clinically, offering cost-effectiveness, portability and user-friendliness. Although clinical validation is crucial, only 13 SSA were scientifically validated, underlying awareness of potential pitfalls and limitations.

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

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

Digital Model in Orthodontics: Is It Really Necessary for Every Treatment Procedure? A Scoping Review

Digital models and three-dimensional technology in orthodontics have become an integral part of everyday clinical practice. Nevertheless, there is currently no consensus regarding in which cases a digital model is really necessary. Therefore, this scoping review aims to identify and assess which orthodontic procedures require a digital model. This review’s reporting was based on PRISMA guidelines. A literature search was undertaken using five electronic databases on 17 February 2024. A total of 87 studies met the inclusion criteria and were qualitatively analyzed by three reviewers. The following aspects of orthodontic treatment were identified and discussed with regard to digital model application: diagnosis, treatment procedures, retention, and outcome evaluation in orthodontics. Based on the studies assessed, despite some limitations regarding radiation exposure justification and the accuracy of the integration methods of 3D data, there is evidence that digital models lead to more accurate orthodontic diagnosis and treatment planning. In cases of impacted canines, aligner treatment, mini-implants insertion (when angle definition and orientation are essential), and primary care for cleft lip and palate, a partial digital model produced by an integration of some of the 3D data (face scan, intraoral scan, CBCT) that we can acquire is beneficial. A full digital model that combines all the 3D information should be used in orthognathic surgery cases, in which prediction and accurate performance are highly advocated.

Imaging and 3D Analysis Based on Two or More Three-Dimensional CBCT Recordings before and after Orthodontic Treatment and Maxillofacial Therapy

Cone beam computed tomography (CBCT) has emerged as a crucial radiographic technique for orthodontic diagnosis and treatment planning, particularly for cases requiring the assessment of complex anatomical relationships. In the first part of the study, we examined metric characteristics measured on 3D cranial models of patients before and after surgery. In the second part, we conducted more complex data processing, analyzing a set of 12 cranial feature points using Procrustes analysis to quantify and visually represent surgical modifications. The third part involved comparing 3D facial surfaces using Iterative Closest Point (ICP) alignment and nearest point-to-point distances. Additionally, we tested point configurations in the facial soft tissues. The study included a group of orthodontic patients from whom CBCT data and 3D facial scans were obtained during treatment. The results demonstrated that each method could assess preoperative and postoperative changes to varying degrees. They also highlighted potential gender differences in surgical modifications that warrant further investigation and consideration during surgical planning. The aim of our study was to compare 3D visualizations of skull and facial models before and after surgery, to assess the degree of relative agreement or similarity, and to identify any morphological differences.

Reducing Leak and Increasing Comfort of an N95 Filtering Facepiece Respirator for Aged-Care Workers Using a Customized, Soft, and Compliant Mask Frame

Abstract This prospective cohort study examines the quantitative fit-factor and tolerability impact of a novel custom frame designed to fit beneath N95 filtering facepiece respirators (FFRs) in a healthcare setting. Conducted at a medium-sized metropolitan residential aged care facility (RACF) in South Australia, sixty participants underwent quantitative fit testing while wearing institutional-provided N95 FFRs. Utilizing three-dimensional (3D) face scanning with a proprietary iPhone app, personalized frames were created using flexible silicone foam with a rigid plastic interior “backbone” to ensure compliance and comfort. Following the fitting of custom frames, participants underwent repeat quantitative fit testing using the same style and size of N95 FFRs. Results indicate a remarkable improvement, with 81.5% of participants achieving a pass on quantitative fit testing when using their custom frame in conjunction with the N95 FFRs, compared to a baseline pass rate of only 21.7% (odds ratio (OR) 20.9, 95% confidence interval (CI): 8.26, 58.50, p < 0.001 via logistic regression). Additionally, participants reported a 2.4 times higher level of tolerability when wearing the custom frame with their N95 FFRs compared to using FFRs alone (p < 0.001). In conclusion, the study demonstrates that wearing a customized frame device under an N95 FFR significantly enhances the likelihood of achieving a pass on quantitative fitting and offers a substantially more tolerable experience for wearers. These findings highlight the potential of personalized frame devices to improve respiratory protection efficacy and wearer comfort in healthcare settings.