Computer-aided Design Program Research Articles

Locating centric occlusion by using intraoral scanners and open access or dental computer-aided design programs: A dental technique

When using conventional methods, centric occlusion (CO) can be determined on conventional gypsum casts that are mounted in an analog articulator at centric relation (CR). In the digital environment, intraoral scanners (IOSs) can be used to record maxillary and mandibular scans articulated in CR. However, a digital protocol to locate the CO on articulated intraoral digital scans at CR by using computer-aided design (CAD) programs is needed. The present manuscript describes a straightforward technique to record CR by combining an IOS and a Kois deprogrammer. Afterwards, the acquired digital data are imported into a CAD program to locate CO. The technique includes a complete digital protocol to locate CO by using 3 different CAD programs: open-access non-dental, open-access dental, and dental CAD program.

Investigating the accuracy of boat propeller blade components with reverse engineering approach using photogrammetry method

This research aims to investigate the accuracy of 3D scanner by conducting a comparative analysis of AI-based photogrammetry method and Agisoft Metashape software, a more affordable and accessible approach compared to expensive commercial solutions. The proposed method uses photogrammetry and CAD (Computer-Aided Design) to measure propeller blade geometry through a three-stage process. In the first stage, the images are taken with a digital camera with calibrated and encoded targets. Additionally, reconstruct the propeller blades in Geomagic Studio. Taking photos of objects only takes a short time and is professional. Subsequently, in the second stage, the 2D images are processed using Agisoft Metashape software and Artificial Intelligence (AI) algorithms to generate an accurate 3-dimensional (3D) model. The third and final stage employs CAD programs to measure various radii of each blade in the 3D virtual model. To validate the accuracy of the measurements, the results are compared with those obtained through machine CMM measurements of each area on the propeller blade. The results show that this method successfully automates the entire reverse engineering process at low cost, lower shooting time, and producing 3D models with high accuracy. The validation shows that the 3D results using Agisoft Metashape have a smaller error (%) value compared to the 3D results using AI. Ultimately, Agisoft Metashape yields higher accuracy results compared to AI, but the results suggest that AI can serve as an alternative for the reverse engineering process in this modern era.

Development of a computational system to design a helical spring

AbstractSprings are the most basic mechanical elements used in transmission mechanisms. The rapid development of the computer and cellular industry has encouraged spring manufacturers to develop the industry to produce very small springs. Most computer-aided design programs for mechanical parts provide the possibility of designing these parts, as these programs include different types of decisions. All these decisions require coordinates for geometric data as well as metadata. The paper aims to develop software programs to design and analyze springs as one of the most significant mechanical elements used. This paper aims to develop a design software of a helical spring system, where this software is built using a computer program in the language of Visual Basic Version 5. When the user enters data into the system, the system will perform a series of complex calculations in the system, then provide a detailed report on all the engineering dimensions of the spring, and test its efficiency. The output of the software shows the required spring wire parameters. The software was tested with test data from the open literature, and the required wire spring parameters were obtained.

Influence of exposure protocol, voxel size, and artifact removal algorithm on the trueness of segmentation utilizing an artificial-intelligence-based system.

To evaluate the effects of exposure protocol, voxel sizes, and artifact removal algorithms on the trueness of segmentation in various mandible regions using an artificial intelligence (AI)-based system. Eleven dry human mandibles were scanned using a cone beam computed tomography (CBCT) scanner under differing exposure protocols (standard and ultra-low), voxel sizes (0.15mm, 0.3mm, and 0.45mm), and with or without artifact removal algorithm. The resulting datasets were segmented using an AI-based system, exported as 3D models, and compared to reference files derived from a white-light laboratory scanner. Deviation measurement was performed using a computer-aided design (CAD) program and recorded as root mean square (RMS). The RMS values were used as a representation of the trueness of the AI-segmented 3D models. A 4-way ANOVA was used to assess the impact of voxel size, exposure protocol, artifact removal algorithm, and location on RMS values (α = 0.05). Significant effects were found with voxel size (p < 0.001) and location (p < 0.001), but not with exposure protocol (p = 0.259) or artifact removal algorithm (p = 0.752). Standard exposure groups had significantly lower RMS values than the ultra-low exposure groups in the mandible body with 0.3mm (p = 0.014) or 0.45mm (p < 0.001) voxel sizes, the symphysis with a 0.45mm voxel size (p = 0.011), and the whole mandible with a 0.45mm voxel size (p = 0.001). Exposure protocol did not affect RMS values at teeth and alveolar bone (p = 0.544), mandible angles (p = 0.380), condyles (p = 0.114), and coronoids (p = 0.806) locations. This study informs optimal exposure protocol and voxel size choices in CBCT imaging for true AI-based automatic segmentation with minimal radiation. The artifact removal algorithm did not influence the trueness of AI segmentation. When using an ultra-low exposure protocol to minimize patient radiation exposure in AI segmentations, a voxel size of 0.15mm is recommended, while a voxel size of 0.45mm should be avoided.

3D Printing in Pharmaceutical Technology as a Promising Tool for the Design and Manufacture of Pharmaceutical Oral Formulation - A Review

By applying material to a substrate, three-dimensional printing is a cutting-edge process that creates three-dimensional things using computer-aided design software and programming. A three-dimensional structure is created by depositing or solidifying successive layers of material in a process known as additive layer manufacturing, or 3D printing. Using a computer-aided design module, medicinal chemicals are designed in three dimensions and converted into a machine-readable form that indicates the outer emergence of the three-dimensional dosage form. This surface is then divided into several printable coats, which are subsequently sent to the machine. Various 3D printing methods have been developed over time to create innovative solid dosage forms, which are some of the most well-known and distinct items available today. The pharmaceutical industry wants to support 3D printing technology and explore the amazing things that can be accomplished with it. Using 3D printing opens up a world of new possibilities for improved medical care. Now that the FDA has approved Spritam, the first 3D-printed tablet, there is precedent for using 3D printing to prepare medication delivery systems. The ability to precisely manage the spatial distribution, precisely dispense small quantities, and assemble layers upon layers facilitates the creation of intricate compositions and geometries. The creation of dosage forms including several active medicinal components with complex and customized release profiles is made possible by the high degree of flexibility and control that comes with 3D printing. A special chance for this technology to prepare customized doses to meet the demands of each particular patient.

Effects of design software program and manufacturing method on the marginal and internal adaptation of esthetic crowns for primary teeth: A microcomputed tomography evaluation

Statement of problemThe adaptation of digitally produced crowns is affected by the design software program and manufacturing method. The effect of artificial intelligence (AI) software program design on the adaptation of the crowns is unclear and comparative evaluations should be documented. PurposeThe purpose of this study was to assess the marginal and internal gaps, the absolute marginal discrepancies, and the 3-dimensional (3D) discrepancy volumes of the resin-based milled and 3D printed crowns for primary teeth designed with computer-aided design (CAD) and AI software programs by using microcomputed tomography (µCT). Material and methodsA total of 40 resin-based esthetic crowns were produced for a prepared typodont tooth (right mandibular primary second molar) according to the design software program (CAD and AI) and manufacturing method (milling and 3D printing) (n=10). Four experimental groups were generated as CAD-milled, CAD-3D printed, AI-milled, and AI-3D printed. The marginal, axial, and occlusal gap values, the absolute marginal discrepancies, and the 3D discrepancy volumes of the specimens were measured by using µCT. The data were analyzed by using 2-way ANOVA and the Tukey HSD tests (α=.05). ResultsThe lowest value for the marginal gap (54 ±43 µm) was observed in the CAD-milled group and the marginal gap value of the AI-3D printed group was significantly lower than the AI-milled group (P<.05). The lowest value for the axial gap (63 ±7 µm) was observed in the AI-3D printed group, and the highest value (145 ±58 µm) was observed in the CAD-milled group; the result for the occlusal gap value was opposite. The highest absolute marginal discrepancy value was observed in the CAD-milled group. The 3D discrepancy volumes increased in the order of the CAD-3D printed, AI-milled, CAD-milled, and AI-3D printed groups. ConclusionsThe marginal and internal gap values of the resin-based crowns were affected by the design software program and manufacturing method; however, tested groups showed clinically acceptable gap values.

A method for estimating the contact area of a dual-mobility total hip prosthesis

The term “contact area” refers to the total surface area of two entities in direct physical touch. When discussing an artificial hip joint, “contact area” refers to the surface area of contact between the components of the artificial hip joint (ball and cup) positioned inside the patient. Several methods can be used to figure out the contact area of an artificial hip joint, such as finite element analysis and traditional experiments on contact mechanics with hip joint simulators. The contact area in an artificial hip joint ensures load distribution. For optimal and long-term performance, the prosthetic hip joint’s contact area must be well understood for design, fitting, and monitoring. This study presented a novel method to estimate the liner surface contact area due to interaction contact in the artificial hip joint using a computer-aided design (CAD) program. This study also contrasted numerical approaches utilizing computer-aided engineering software and theoretical predictions based on Hertz theory with three-dimensional processes using CAD software to determine the contact area in the inner liner. There were no significant discrepancies in the outcomes of the three approaches.

Biomechanical comparative finite element analysis between a conventional proximal interphalangeal joint flexible hinge implant and a novel implant design using a rolling contact joint mechanism

BackgroundThe rolling contact joint (RCJ) mechanism is a system of constraint that allows two circular bodies connected with flexible straps to roll relative to one another without slipping. This study aims to compare the biomechanical characteristics between the conventional proximal interphalangeal joint (PIPJ) flexible hinge (FH) implant and the novel PIPJ implant adopting a RCJ mechanism during PIPJ range of motion using finite element (FE) analysis.MethodsThe three-dimensional (3D) surface shape of a conventional PIPJ FH implant was obtained using a 3D laser surface scanning system. The configuration and parameters of the novel PIPJ implant were adapted from a previous study. The two implants were assumed to have the same material characteristics and each implant was composed of a hyperelastic material, silicone elastomers. The configuration data for both implants were imported to a computer-aided design program to generate 3D geometrical surface and hyperelastic models of both implants. The hyperelastic models of both implants were imported into a structural engineering software to produce the FE mesh and to perform FE analysis. The FE analysis modeled the changes of mechanics during flexion–extension motion between 0° and 90° of two PIPJ implants. The mean and maximum values of von-Mises stress and strain as well as the total moment reaction based on the range of motion of the PIPJs were calculated. The mean values within the PIPJ’s functional range of motion of the mean and maxinum von-Mises stress and strain and the total moment reaction were also determined.ResultsThe maximum values for the von-Mises stress, and strain, as well as the total moment reactions of the conventional PIPJ FH and novel PIPJ implants were all at 90° of PIPJ flexion. The maximum value of each biomechanical property for the novel PIPJ implant was considerably lower compared with that of the conventional PIPJ FH implant. The mean values within the PIPJ’s functional range of motion of the maximum von-Mises stress and strain for the novel PIPJ implant was approximately 6.43- and 6.46-fold lower compared with that of the conventional PIPJ FH implant, respectively. The mean value within a PIPJ’s functional range of motion of the total moment reaction of the novel PIPJ implant was approximately 49.6-fold lower compared with that of the conventional PIPJ FH implant.ConclusionsThe novel PIPJ implant with an RCJ mechanism may offer improved biomechanical performance compared with conventional PIPJ FH implant.

Studying 3d modeling and prototyping in pre-professional classes with the help of the T-FLEX CAD program. Implementation of the project result in the form of an educational startup

The article continues the consideration of using the Russian computer-aided design program T-FLEX CAD to study 3D modeling and prototyping in pre-professional engineering classes, which began in the journal "Informatics at School" No 5-2022. The use of this program when performing an individual project is presented.Practical works are offered that are aimed at creating a model and prototype of a respirator mask. The result of the works is the technical part of an individual project, which can be realized as an educational startup. When realizing the project as an educational startup, legal regulations, financing opportunities and other features of implementing such a project for continuing education are considered.The material will be useful for teachers of informatics and technology working in engineering or information and technology classes, when teaching an advanced course in informatics or a special course in 3D modeling and prototyping.

The Center of Resistance of an Impacted Maxillary Canine: A Finite Element Analysis

The aim of this study was to calculate the center of resistance (COR) of an impacted maxillary canine according to the stages of pericoronal tissue healing using the finite element method (FEM). The maxillary canine model was three-dimensionally scanned, and the structures surrounding the tooth were modeled using a computer-aided design program. The COR was calculated in the buccolingual (BL) and mesiodistal (MD) directions using the FEM. After applying a single force to a specific point of the tooth, several counter moments were applied to compensate for this at the same point. Thereafter, the displacement curve of the tooth axis for each counter moment was plotted. The intersection points between the displacement curves corresponded to the COR. At the beginning of healing, the COR of the MD and BL direction was located at 38.1% and 38.7% of the root length from the cementoenamel junction, respectively. At the end of healing, the COR of the MD and BL direction was located at 44.6% and 49.8% of the crown length from the cementoenamel junction, respectively. The COR of the impacted maxillary canine gradually shifts to the coronal side as the healing of the pericoronal tissue occurs.

Virtual implant scan body switch by using computer-aided design programs avoiding the need of obtaining a new intraoral implant digital scan: A novel protocol.

The present manuscript describes a technique to virtually switch an implant scan body eliminating the need of obtaining a new intraoral implant digital scan. Implant scan bodies assist on transferring the 3-dimensional position of the implants into the virtual definitive implant cast. However, if a different implant part is desired during the designing procedures of the implant restoration such as selecting a different implant abutment of varying height, angulation, or manufacturer, a new intraoral implant digital scan with the specific implant scan body is required. This novel protocol aims to reduce possible complications that require capturing a new intraoral implant digital scan, facilitate prostheses design modifications after the obtention of the definitive intraoral implant digital scan, and to ease the manufacturing procedures. The novel technique may provide a solution for virtually switch implant scan bodies for fabricating implant-supported single crowns or short-span prostheses. Additional studies are needed before its clinical implementation.

Advancements in Oral Maxillofacial Surgery: A Comprehensive Review on 3D Printing and Virtual Surgical Planning

This comprehensive review explores the advancements in Orthognathic and Oral Maxillofacial Surgery, focusing on the integration of 3D Printing and Virtual Surgical Planning (VSP). Traditional surgical methods, while effective, come with inherent risks and complications, and can lead to variability in outcomes due to the reliance on the surgeon’s skill and experience. The shift towards patient-centric care necessitates personalized surgical methods, which can be achieved through advanced technology. The amalgamation of 3D printing and VSP revolutionizes surgical planning and implementation by providing tactile 3D models for visualization and planning, and accurately designed surgical guides for execution. This convergence of digital planning and physical modeling facilitates a more predictable, personalized, and precise surgical process. However, the adoption of these technologies presents challenges, including the need for extensive software training and the steep learning curve associated with computer-aided design programs. Despite these challenges, the integration of 3D printing and VSP paves the way for advanced patient care in orthognathic and oral maxillofacial surgery.

Clinical evaluation of the agreement between virtual and clinical occlusal registrations: A comparative clinical study

The accuracy of virtual interocclusal records has been evaluated, but clinical studies comparing the clinical output to the virtual design are lacking. The purpose of this clinical study was to evaluate the agreement between the virtual occlusal scheme designed by a computer-aided design and computer-aided manufacturing software program and the occlusal scheme obtained clinically on the definitive prosthesis assessed with articulating paper. The virtual occlusal scheme design of 20 single monolithic crowns and their adjacent teeth was obtained by using an intraoral scanning system in 17 participants. These registrations were compared with conventional occlusal records obtained by applying articulating paper in 2 stages: first with 200-μm blue film and the second with 12-μm metallic red articulation tape. The analysis included both the quantity and the quality of the contacts of the conventional occlusal records referred to as the standard method. For accuracy analysis, virtual record sensitivity was calculated per crown as the percentage of true positive virtual contacts of the actual contacts identified by articulating paper. Specificity was also calculated as the percentage of true negative virtual contacts of the actual sites of clearance. The virtual record sensitivity was 98.5 (95% confidence interval [CI] 96-100) for the crowns and 95 (95% CI 85-100) for the adjacent teeth. The virtual record specificity was 88.6 (95% CI 82.4-94.8) for the crowns and 82.6 (95% CI 77.5-87.6) for the adjacent teeth. The agreement between the clinical and virtual contact intensities on the crowns was 83 (95% CI 73-93) and 67.3 (95% CI 56-78.7) for the adjacent teeth. The positive predictive value was 72.83 (95% CI 60-86). The negative predictive value was 100% (95% CI 100-100). The intraoral scanning system provided clinically sufficient sensitivity and specificity for identifying the occlusal surface contacts of monolithic crowns. A slight decrease was detected in the system's sensitivity and specificity in identifying contacts on adjacent teeth and a larger decrease identifying the intensity of these contacts.

INTELLECTUAL PROPERTY RIGHTS FOR 3D BIOPRINTING IN MALAYSIA

Additive manufacturing in the field of tissue engineering has evolved rapidly over the past few decades. 3D bioprinting is an extendedapplication of additive manufacturing that involves the building of tissue or organ in a layer-by-layer manner using a bioprintervia instructions from computer graphic software. 3D bioprinting technology offers promise in the transformation of healthcare sectors. Consequently, disputes regarding commercial use of 3D bioprinting, in particular on intellectual property rights will arise. Patent ownership and registration of bioprinting products and processes pose issues of ethics. The copyrighted works of 3D bioprinting software pose risks of copyright infringement. Besides, there is also a question of whether the marks and brand of 3D bioprinters can be protected as trademarks. The main objective of this study is to analyse how existing intellectual property laws in Malaysia can be utilized to protect 3D bioprinting technology intellectual property rights. The qualitative method is employed in this study, in particular, content analysis of journal articles, books, international conventions, directives, statutes and court cases. Semi-structured interviews with two respondents from relevant ministries were conducted to achieve the objectives of this study. Additionally, a comparative study of legal frameworks in the United States and Europe is adopted to examine intellectual property rights on the international stage. The study revealed that 3D bioprinting products and processes are patentable under the PatentsAct 1983; however, ethical and morality issues are challenges in granting protection. Apart from that, copyright can protect computeraided bioprinting design software and programs under the Copyright Act 1987 and the marks and brand of 3D bioprinting products can be protected under the Trademark Act 2019. The findings of this study will expose the potential in commercialization of 3D bioprinting among industry players and propose improvements to the current regulatory framework of 3D bioprinting related to intellectual property rights.

Passive Isolator Design and Vibration Damping of EO/IR Gimbal Used in UAVs

One of the most critical factors affecting the quality of the images captured by the surveillance systems used in the unmanned aerial vehicles is the vibrations transmitted from the aircraft to the gimbal. The gimbal used in unmanned aerial vehicles is essential equipment, holding the camera steadily and accurately and pointing it in the desired direction. Within the scope of this article, a passive vibration isolation system design has been made for the two-axis electro-optical gimbal used in the mini unmanned aerial vehicle. By choosing the spring-damper system among different methods, the design that isolates the harmonic vibration from the platform on a single axis has been made using the analytical method. The analytical method was used to create a design that isolates the harmonic vibration from the platform along a single axis. In addition, the part named 'Pan Yoke', which contains this damper system, was designed with a computer-aided design program, and natural frequency values were checked with Ansys modal analysis. The frequency of the vibration transmitted from the air vehicle to the gimbal and the natural frequency of the designed part have been determined to be close to each other, at around 200 Hz. The natural frequency values of this part were optimised with various design changes and topology optimisations to prevent the part from resonating.

A Lineage-Based Referencing DSL for Computer-Aided Design

3D Computer-Aided Design (CAD) modeling is ubiquitous in mechanical engineering and design. Modern CAD models are programs that produce geometry and can be used to implement high-level geometric changes by modifying input parameters. While there has been a surge of recent interest in program-based tooling for the CAD domain, one fundamental problem remains unsolved. CAD programs pass geometric arguments to operations using references, which are queries that select elements from the constructed geometry according to programmer intent. The challenge is designing reference semantics that can express programmer intent across all geometric topologies achievable with model parameters, including topologies where the desired elements are not present. In current systems, both users and automated tools may create invalid models when parameters are changed, as references to geometric elements are lost or silently and arbitrarily switched. While existing CAD systems use heuristics to attempt to infer user intent in cases of this undefined behavior, this best-effort solution is not suitable for constructing automated tools to edit and optimize CAD programs. We analyze the failure modes of existing referencing schemes and formalize a set of criteria on which to evaluate solutions to the CAD referencing problem. In turn, we propose a domain-specific language that exposes references as a first-class language construct, using user-authored queries to introspect element history and define references safely over all paths. We give a semantics for fine-grained element lineage that can subsequently be queried; and show that our language meets the desired properties. Finally, we provide an implementation of a lineage-based referencing system in a 2.5D CAD kernel, demonstrating realistic referencing scenarios and illustrating how our system safely represents models that cause reference breakage in existing CAD systems.

Influence of occlusal collision corrections completed by two intraoral scanners or a dental design program on the accuracy of the maxillomandibular relationship

Statement of problemOcclusal collisions of articulated intraoral digital scans can be corrected by intraoral scanners (IOSs) or dental design software programs. However, the influence of these corrections on the accuracy of maxillomandibular relationship is unclear. PurposeThe purpose of this clinical investigation was to measure the effect of occlusal collision corrections completed by the IOSs or dental design software programs on the trueness and precision of maxillomandibular relationship. Material and methodsCasts of a participant mounted on an articulator were digitized (T710). The experimental scans were obtained by using 2 IOSs: TRIOS4 and i700. The intraoral digital scans of the maxillary and mandibular arches were obtained and duplicated 15 times. For each duplicated pair of scans, a bilateral virtual occlusal record was acquired. Articulated specimens were duplicated and assigned into 2 groups: IOS-not corrected and IOS corrected (n=15). In the IOS-not corrected groups, the IOS software program postprocessed the scans maintaining the occlusal collisions, while in the IOS-corrected groups, the IOS software program eliminated the occlusal collisions. All articulated specimens were imported into a computer-aided design (CAD) program (DentalCAD). Three subgroups were developed based on the CAD correction: CAD-no change, trimming, or opening the vertical dimension. Thirty-six interlandmark distances were measured on the reference and each experimental scan to compute discrepancies by using a software program (Geomagic Wrap). Root mean square (RMS) was selected to compute the cast modifications performed in the trimming subgroups. Trueness was examined using 2-way ANOVA and pairwise comparison Tukey tests (α=.05). Precision was evaluated with the Levene test (α=.05). ResultsThe IOS (P<.001), the program (P<.001), and their interaction (P<.001) impacted the trueness of the maxillomandibular relationship. The i700 obtained higher trueness than the TRIOS4 (P<.001). The IOS-not corrected-CAD-no-changes and IOS-not-corrected-trimming subgroups obtained the lowest trueness (P<.001), while the IOS-corrected-CAD-no-changes, IOS-corrected-trimming, and IOS-corrected-opening subgroups showed the highest trueness (P<.001). No significant differences in precision were found (P<.001). Furthermore, significant RMS differences were found (P<.001), with a significant interaction between Group×Subgroup (P<.001). The IOS-not corrected-trimmed subgroups obtained a significantly higher RMS error discrepancy than IOS-corrected-trimmed subgroups (P<.001). The Levene test showed a significant discrepancy in the RMS precision among IOSs across subgroups (P<.001). ConclusionsThe trueness of the maxillomandibular relationship was influenced by the scanner and program used to correct occlusal collisions. Better trueness was obtained when the occlusal collisions were adjusted by the IOS program compared with the CAD program. Precision was not significantly influenced by the occlusal collision correction method. CAD corrections did not improve the results of the IOS software. Additionally, the trimming option caused volumetric changes on the occlusal surfaces of intraoral scans.

Using the Finite Element Method to Determine the Odonto-Periodontal Stress for a Patient with Angle Class II Division 1 Malocclusion.

The finite element method (FEM) is a computational method that can solve all biomechanical problems, including the field of orthodontics. The purpose of this virtual experimental study is to determine the behavior of a real orthodontic system subjected to different systems of loads. To analyze the real orthodontic system, we studied the case of a 21-year-old female patient. We used the InVesalius program, which can transform a set of DICOM-type images taken from cone beam computed tomography (CBCT) into three-dimensional structures. These structures were edited, modified, completed, and analyzed from a geometric point of view with the help of the Geomagic software. The final result of these operations must be a three-dimensional model made up of perfectly closed surfaces so that they can be transformed into virtual solids. The model consisting of perfectly closed surfaces is loaded into computer-aided design (CAD) programs. Bracket and tube components, as well as orthodontic wires, can be added to these models, similar to the analyzed patient's tissues. When the model is complete and geometrically correct, it is exported to a program that uses FEM, such as Ansys Workbench. The simulation was performed for the forces of 0.5, 0.6, 0.7, 0.8, 0.9, and 1 N. The intention was to determine the behavior of the entire orthodontic system for these force values. After running the simulations, result maps were obtained that were composed of displacement, strain, and stress diagrams. It was also found that, in addition to the known rigidity, the orthodontic system has some elasticity due to the orthodontic wires, as well as the periodontal ligaments. Thus, a virtual analysis study can be carried out starting from a real patient with pre-treatment CBCT images and the virtual models of the bracket and tube elements and of the orthodontic wires.

Dependence of the Color Tunability on the H2Pc Thickness in DC-Voltage-Driven Organic Light-Emitting Diodes

Dependence of the color tunability on the metal free Phthalocyanine (H2Pc) layer thickness in DC-voltage-driven organic light-emitting diodes (OLEDs) was investigated. A H2Pc layer was employed as a blue/red emission layer, which was prepared on an Alq3 green emission layer. The thickness of the H2Pc layer varied from 5 to 30 nm, with a step of 5 nm. The fabricated color-tunable OLEDs (CTOLEDs) were subjected to a thermal treatment layer for 2 min at a temperature of 120 °C to improve the interface properties, especially between H2Pc and Alq3. The current density–voltage–luminance characteristics and Commission Internationale de L’Eclairage (CIE) coordinates of the CTOLEDs with and without thermal treatment were measured, and their energy band diagrams were analyzed with respect to the H2Pc thin film thicknesses. In addition, the recombination rates at the interfaces between the hole transport layer and Alq3 and the H2Pc/electron transport layer of the CTOLEDs with and without thermal treatment were theoretically investigated using a technology–computer-aided design (TCAD) program. The experimental and theoretical results showed that the emission color temperature from cool white to warm white at a low voltage can be controlled by adjusting the thickness of the H2Pc layer in the CTOLED. It was verified that the thermally treated H2Pc thin film layer acted as a barrier that prevented electrons from being transferred to the Alq3 at low applied voltages, resulting in white color emission with temperature tunability. The CTOLED with a 20 nm of H2Pc layer demonstrated the best stable interface state and stability, resulting in the lowest driving voltage, relatively high luminance, and optimal light emission uniformity, respectively.

Evaluating the Use of CT-Derived Lung Volumes in Donor-Recipient Lung Size Matching for Lung Transplantation in Patients With Interstitial Lung Disease and/or Idiopathic Pulmonary Fibrosis

This study aims to assess the efficacy of current measurement strategies for lung sizing and the feasibility of future use of computed tomography (CT)-derived lung volumes to predict a donor-recipient lung size match during bilateral lung transplants. We reviewed the data of 62 patients who underwent bilateral lung transplantation for interstitial lung disease and/or idiopathic pulmonary fibrosis from 2018 to 2019. Data for recipients was retrieved from the department's transplant database and medical records, and the donor's data was retrieved from the DonorNet. The data included demographic data, lung heights, measured total lung capacity (TLC) from plethysmography for recipients and estimated TLC for donors, clinical data, and CT-derived lung volumes in both pre- and post-transplant recipients. The post-transplant CT-derived lung volume in recipients was used as a surrogate for donor lung CT volumes due to inadequate or poor donor CT data. Computed tomography-derived lung volumes were calculated using thresholding, region growing, and cutting techniques on Computer-Aided Design and Mimics (Materialise NV, Leuven, Belgium) programs. Preoperative CT-derived lung volumes in recipients were compared with the plethysmography TLC, Frustum Model, and donor-predicted TLC. The ratio of the recipient's pre-and postoperative CT-derived volumes, the ratio of preoperative CT-derived lung volume, and donor-estimated TLC were studied to detect a correlation with 1-year outcomes. The recipient preoperative CT-derived volume correlated with the recipient preoperative plethysmography TLC (Pearson correlation coefficient [PCC] of 0.688) and with the recipient Frustum model volume (PCC of 0.593). The recipient postoperative CT-derived volume correlated with the recipient's postoperative plethysmography TLC (PCC of 0.651). There was no statistically significant correlation between recipients' CT-derived pre- or postoperative volume with donor-estimated TLC. The ratio of preoperative CT-derived volume to donor-estimated TLC correlated inversely with the length of ventilation (P value=.0031). The ratio of postoperative CT-derived volume to preoperative CT-derived volume correlated inversely with delayed sternal closure (P=.0039). No statistically significant correlations were found in evaluating outcomes related to lung oversizing in the recipient (defined as a postoperative to preoperative CT-derived lung volume ratio of >1.2). Generating CT-derived lung volumes is a valid and convenient method for evaluating lung volumes for transplantation in patients with ILD and/or IPF. Donor-estimated TLC should be interpreted carefully. Further studies should derive donor lung volumes from CT scans for a more accurate evaluation of lung size matching.