BACKGROUND AND OBJECTIVES

Mouth retractors are essential in ensuring efficient yet safe exposure of the oral cavity and oropharynx. However, when applied improperly or haphazardly, retractors can cause tissue injuries and compromise patient safety. In addition, there are gaps in the usability of existing designs. This study aimed to identify the issues encountered by otorhinolaryngology surgeons in the use of commercially available mouth retractors, design and fabricate an improved retractor, and explore the use of additive manufacturing (popularly known as 3D printing) for retractor prototyping.

The study used the United States Food and Drug Administration (US FDA) Design Control as its framework. End-user requirements from otorhinolaryngologists were collected through key informant interviews. Results were organized into a Design Input template which was used to guide the design and development process. Prototype designs were iteratively created using computer-aided design software and 3D printing. Once design specifications were satisfied, a beta prototype was fabricated and given to another cohort of otorhinolaryngologists. The participants assessed the usability of the beta prototype. System Usability Scale (SUS) was used to quantify participant's feedback.

Five designs were created in the course of the study. The final prototype was fabricated using a Stereolithography (SLA) 3D printer. Several features were developed to address user requirements. The primary modification was to make the retractor modular to facilitate easier and shorter mounting and assembly. Gingival injury was addressed with the replacement of the maxillary alveolus hook with support bars. Five participants evaluated the beta prototype which received a mean SUS score of 75, well above the 50th percentile threshold.

This study demonstrates the applicability of the US FDA Design Control Process in the local setting to improve the mouth retractor design. Clinical and ergonomic issues were identified and design solutions were proposed and some have been implemented in a low-fidelity prototype. Results of the small-scale usability test suggest that the present form factor can be the basis for further iterations. Future studies can implement the proposed features to address other clinical and ergonomic needs.

No abstract available.
Printing, Three-Dimensional*

No abstract available.
Printing, Three-Dimensional*

Additive manufacturing (AM) is a collection of technologies based on the layer-by-layer manufacturing. Characterized by its direct manufacturing and rapidity, it has been regarded by the Economist Journal as one of the key techniques which will trigger the third industry reformation. The present article, beginning with a brief introduction of the history of AM and the process of its major technologies, focuses on the advantages and disadvantages and medical applications of the technique.
Medicine ; Printing, Three-Dimensional

Full arch models play an important role in clear aligner orthodontic therapy and the preparation of prosthodontic appliances. Three dimensional (3D) printed full arches are very popular with the benefit of easy production and good mechanical properties for fabricating clear aligner. However, the accuracy of 3D printed full arches after long storage have not been proved yet. The objective of this study was to estimate the long-term accuracy of 3D full arches produced by the four types of 3D printers (stereo-lithography apparatus (SLA), digital light projector (DLP), Polyjet™ (POL), and fused deposition modeling (FDM)) following an accelerated aging treatment. The highest accuracy was produced by POL (before treatment) and SLA (after treatment) group, respectively. Comparisons between absolute mean trueness for the 3D printed full arches before and after treatment indicated that the deviation of the trueness values of FDM group were significantly higher than those of other experimental groups (p<0.05). In addition, all trueness relative errors for FDM group were greater than 0.04 after treatment, which was high compared to those of other experimental groups. Therefore, the long-term storage of full arches fabricated by FDM type 3D printer is not recommended and the 3D printed full arches should be used immediately whenever possible.
Aging ; Printing, Three-Dimensional

Background: In this study, 3D printed floating tablet devices for Metronidazole (MTZ) were developed to prolong its exposure with Helicobacter pylori and eradicate it from causing peptic ulcer Objectives: To utilize Quality by Design (QbD) in the development of the tablet devices through Fused Deposition Modelling (FDM) 3D printing. This aimed to develop and construct optimized design dimensions of tablet devices subject for characterization. Methodology: Tablet designs were established using QbD, Design Failure Mode Effect and Analysis (DFMEA) and 2 factorial design. Four floating tablets devices were developed through FDM 3D printing using Polyvinyl alcohol (PVA) filament. Characterization tests determined their dimensions, density, floating mechanism, in vitro dissolution rate, drug release kinetics, surface morphology, infill and thermal characteristics. Significance of the QbD model was also assessed. Results: Density of all devices were less than 1.004 g/cm . The floating Lag time (FLT) showed instant floatation and Total Floating Time (TFT) lasted for an average of 1 hour. Drug release kinetics show Korsmeyer-Peppas kinetics. Thermal characteristics fall within o o 186.12 C-187.27 C. 3D CTX-ray results show accuracy of printing 3D renders. Tablet device 3 exhibited the best surface morphology, longest floating time and slowest drug release. Conclusion The study successfully developed 3D printed floating tablet devices for Metronidazole with sustained release mechanism. Thus, utilizing QbD in pre-formulation studies using novel technology is essential in optimizing drug dosage forms. Plots from Design Expert Software show the significant design models.
Printing, Three-Dimensional

Humans ; Otolaryngology ; Printing, Three-Dimensional

OBJECTIVE: This paper introduces the key content and background of Technical Review Guidance for the Registration of Personalized Additive Manufacturing Medical Devices of Passive Implantable Bone, Joint and Oral Hard Tissues. METHODS: The core contents and importance of the construction of personalized design validation and verification and additive manufacturing system are described respectively. RESULTS: The personalized design needs to be carried out under the control of interactive cooperation between healthcare professional and engineer. And the performance of personalized device must be validated and verified completely. At the same time, in view of the particularity of the quality management system of additive manufacturing, the technical focus is expounded. CONCLUSIONS New ideas and methods shall be used in evaluate and administrate personalized additive manufacturing medical device.
Printing, Three-Dimensional ; Prostheses and Implants

PURPOSE: Manufacturing with AM (Additive manufacturing) technique has many advantages; but, due to insufficient study in the area, it is not being widely used in the general clinic. In this study, differences of flexural strength among various materials of 3 unit fixed dental prosthesis were analyzed. MATERIALS AND METHODS: A metal jig for specimens that had a 3-unit-fixed dental prosthesis figure were fabricated. The jigs were made appropriately to the specifications of the specimens. Three different kinds of materials of specimens which were NC (mathacrylic esther based), DP-1 (Bisphenol A epoxy acrylate type oligomer based), and DT-1 (urethane acrylate based) were printed with DLP machine. Five specimens for each kind of material were printed with an angle of 30° from the horizontal surface. The specimens were placed on the jig and the flexural strength was measured and recorded using Universal testing machine. The recorded data was analyzed in SPSS using One-way ANOVA and Tukey HSD to determine the significance of the differences of flexural strength among the groups. RESULTS: The flexural strengths of each group were the followings: NC, 1119 ± 305 N; DP-1, 619 ± 150 N; DT-1, 413 ± 65 N. Using One-way ANOVA and Tukey Honestly Significant Difference test, significant difference was found between NC and the other groups (P < 0.05), but there was no significant difference between DP-1 and DT-1 (P > 0.05). CONCLUSION: Higher flexural strength was shown in 3-unit-fixed dental prosthesis that were 3D printed using a DLP machine with NC material.
Dental Prosthesis ; Printing, Three-Dimensional

: In the field of Urology, flexible ureterorenoscopy (fURS) remains a challenging skill for junior residents to develop due to its steep learning curve. Hence, training models were incorporated into simulation-based training to allow for novice trainees to overcome the learning curve without potentially compromising patient outcomes and minimize complications. OBJECTIVE: To describe the design and test the validity of a non-biological three-dimensional (3D) model of the pelvocalyceal system as a tool for simulation-based training for flexible ureterorenoscopy. METHODS: This was a prospective, quasi-experimental, surgical innovation research stage 2a study conducted in a tertiary government hospital. The retrograde intrarenal surgery (RIRS) box was composed of four siliconized pelvocalyceal systems which were 3D printed using computed tomography urograms of actual patients. Thirty-two urologists were asked to perform flexible ureteroscopy using the RIRS box and were given a questionnaire to assess face and content validity using the Likert scale. RESULTS: The RIRS Box training model showed good face and content validity. The 3D printed pelvocalyceal system was judged to have a close anatomical resemblance to an actual calyceal system. While performing fURS, the RIRS box provided similar pelvocalyceal visualization and instrument handling as in an actual procedure. Majority of participants considered the training model useful for training (75%) and believed that it may improve the RIRS technique (46.8%). CONCLUSION The RIRS Box training model may help urologists improve the manner in which they acquire technical knowledge and skills necessary in performing fURS.
Ureteroscopy ; Ureteroscopes ; Printing, Three-Dimensional