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.

Background and Objective: To design and fabricate a suction port adapter to use various sizes of suction cannulas with a wireless otoendoscope enabling ear cleaning under endoscopic guidance demonstrated using an ear examination simulator. Methods: Design: Instrument Innovation. Setting: Tertiary Private Training Hospital. Patient: Ear Examination Simulator. Results: The fabricated suction port adapters were able to hold the wireless otoendoscope and suction cannulas together, allowing simultaneous inspection of the ear canal and suctioning of ear canal debris using the Ear Examination Simulator. Conclusion Our prototype 3D-printed suction port adapters for a wireless otoendoscope may improve ear cleaning by enhancing the accuracy of suctioning debris and decreasing duration since they hold the suction cannulas in place under endoscopic guidance. They may aid ENT physicians in easier visualization and simultaneous ear cleaning of patients and improve ear cleaning techniques and times, especially among less experienced physicians, but actual clinical trials are needed to confirm this.
Printing, Three-Dimensional ; Cerumen ; Otoscopy

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

OBJECTIVE: To compare the effectiveness of O-arm navigation and C-arm navigation for guiding percutaneous long sacroiliac screws in treatment of Denis type Ⅱ sacral fractures. METHODS: A retrospective study was conducted on clinical data of the 46 patients with Denis type Ⅱ sacral fractures between April 2021 and October 2022. Among them, 19 patients underwent O-arm navigation assisted percutaneous long sacroiliac screw fixation (O-arm navigation group), and 27 patients underwent C-arm navigation assisted percutaneous long sacroiliac screw fixation (C-arm navigation group). There was no significant difference in gender, age, causes of injuries, Tile classification of pelvic fractures, combined injury, the interval from injury to operation between the two groups ( P>0.05). The intraoperative preparation time, the placement time of each screw, the fluoroscopy time of each screw during placement, screw position accuracy, the quality of fracture reduction, and fracture healing time were recorded and compared, postoperative complications were observed. Pelvic function was evaluated by Majeed score at last follow-up. RESULTS: All operations were completed successfully, and all incisions healed by first intention. Compared to the C-arm navigation group, the O-arm navigation group had shorter intraoperative preparation time, placement time of each screw, and fluoroscopy time, with significant differences ( P<0.05). There was no significant difference in screw position accuracy and the quality of fracture reduction ( P>0.05). There was no nerve or vascular injury during screw placed in the two groups. All patients in both groups were followed up, with the follow-up time of 6-21 months (mean, 12.0 months). Imaging re-examination showed that both groups achieved bony healing, and there was no significant difference in fracture healing time between the two groups ( P>0.05). During follow-up, there was no postoperative complications, such as screw loosening and breaking or loss of fracture reduction. At last follow-up, there was no significant difference in pelvic function between the two groups ( P>0.05). CONCLUSION Compared with the C-arm navigation, the O-arm navigation assisted percutaneous long sacroiliac screws for the treatment of Denis typeⅡsacral fractures can significantly shorten the intraoperative preparation time, screw placement time, and fluoroscopy time, improve the accuracy of screw placement, and obtain clearer navigation images.
Humans ; Fracture Fixation, Internal/methods* ; Retrospective Studies ; Imaging, Three-Dimensional ; Bone Screws ; Surgery, Computer-Assisted ; Tomography, X-Ray Computed ; Spinal Fractures/surgery* ; Fractures, Bone/surgery* ; Pelvic Bones/injuries* ; Postoperative Complications ; Neck Injuries

OBJECTIVES: To examine the reliability and accuracy of Walker's model for estimating the sex of Han adults in western China by using cranium three-dimensional (3D) CT reconstruction, and to study the suitable cranial sex estimation model for Han people in western China. METHODS: A total of 576 cranial CT 3D reconstructed images from Hanzhong Hospital in Shaanxi Province from 2017 to 2021 were collected. These images were divided into the experimental group with 486 samples and the validation group with 90 samples. Walker's model was used by observer 1 to estimate the sex of experimental group samples. The logistic function applicable to Han people in western China was corrected by observer 1. The 90 samples in the validation group were scored and substituted into the modified logistic function to complete the back substitution test by observer 1, 2 and 3. RESULTS: The accuracy of sex estimation of Han adults in western China was 63.2%-77.2% by applying Walker's model. The accuracy of modified logistic function was 82.9%. The accuracy of sex estimation through back substitution test by 3 observers was 75.6%-91.1%, with a Kappa value of 0.689 (P<0.05) for inter-observer consistency and 0.874 (P<0.05) for intra-observer consistency. CONCLUSIONS There are great differences in bone characteristics among people from different regions. The modified logistic function can achieve higher accuracy in Han adults in western China.
Humans ; Adult ; Reproducibility of Results ; Sex Determination by Skeleton/methods* ; Forensic Anthropology ; Skull/anatomy & histology* ; Imaging, Three-Dimensional ; China ; Tomography, X-Ray Computed

Digital guided therapy (DGT) has been advocated as a contemporary computer-aided technique for treating endodontic diseases in recent decades. The concept of DGT for endodontic diseases is categorized into static guided endodontics (SGE), necessitating a meticulously designed template, and dynamic guided endodontics (DGE), which utilizes an optical triangulation tracking system. Based on cone-beam computed tomography (CBCT) images superimposed with or without oral scan (OS) data, a virtual template is crafted through software and subsequently translated into a 3-dimensional (3D) printing for SGE, while the system guides the drilling path with a real-time navigation in DGE. DGT was reported to resolve a series of challenging endodontic cases, including teeth with pulp obliteration, teeth with anatomical abnormalities, teeth requiring retreatment, posterior teeth needing endodontic microsurgery, and tooth autotransplantation. Case reports and basic researches all demonstrate that DGT stand as a precise, time-saving, and minimally invasive approach in contrast to conventional freehand method. This expert consensus mainly introduces the case selection, general workflow, evaluation, and impact factor of DGT, which could provide an alternative working strategy in endodontic treatment.
Humans ; Consensus ; Endodontics/methods* ; Tooth ; Printing, Three-Dimensional ; Dental Care ; Cone-Beam Computed Tomography ; Root Canal Therapy

OBJECTIVES: This study aimed to explore the relationship between alveolar cleft and secondary nasal deformity post unilateral cleft lip repair in adults. METHODS: A total of 27 patients aged 16-30 years old with unilateral secondary nasal deformity and alveolar cleft were included, 13 of whom underwent bone grafting. Spiral CT data of all preoperative and postoperative patients who had alveolar bone grafting were collected. Then, Mimics software was used for three-dimensional reconstruction to evaluate the correlation between the width, height, and volume of the alveolar cleft and those of the nasal deformity. The difference in nasal deformity before and after alveolar bone grafting was also explored. RESULTS: The width of the alveolar cleft was positively correlated with the difference in bilateral nostril floor width (P<0.05). As the effective depth of the alveolar cleft increased, the sub-alare inclination angle largened (P<0.05). However, no significant difference was found in the nasal deformity between before and after alveolar bone grafting. CONCLUSIONS Alveolar cleft is closely related to secondary nasal deformities post unilateral cleft lip repair, especially nasal floor deformities. Alveolar bone grafting benefits adult patients for the improvement of secondary nasal deformities post unilateral cleft lip repair.
Humans ; Adult ; Adolescent ; Young Adult ; Nose/surgery* ; Cleft Lip/surgery* ; Rhinoplasty/methods* ; Imaging, Three-Dimensional ; Treatment Outcome ; Cleft Palate/complications*

Using digital technologies in concurrently performing missing tooth implantation and preparation of remaining teeth is a solution to reduce the number of visits and improve efficiency. This paper proposes a digital process for simultaneously implanting and preparing teeth. It integrates implant surgical guide and 3D-printed tooth preparation guide into a single guide and completes guided implant placement and precise tooth preparation. Based on "repair-oriented" virtual implant planning, the implant surgical guide can improve the efficiency and predictability of implant placement, and its linear accuracy is about 1 mm. The tooth preparation guide precisely guides tooth preparation and restoration space visualization, ensuring the quality of the tooth preparation. The two guides have different design accuracy requirements, and thus their combination improves the overall guiding accuracy requirements. The concurrent application of the two guides minimizes the clinical operation time, number of visits, and economic burden of patients.
Humans ; Surgery, Computer-Assisted ; Dental Implantation, Endosseous ; Printing, Three-Dimensional ; Technology ; Tooth Preparation ; Computer-Aided Design ; Dental Implants ; Imaging, Three-Dimensional ; Cone-Beam Computed Tomography

Orthognathic surgery, which involve osteotomy and repositioning of the maxillomandibular complex, has recently emerged as a crucial method of correcting dentofacial deformities. The optimal placement of the maxillomandibular complex holds utmost significance during orthognathic surgery because it directly affects the surgical outcome. To accurately achieve the ideal position of the maxillomandibular complex, with the rapid advancements in digital surgery and 3D-printing technology, orthognathic surgery has entered an era of "Precision Surgery" from the pervious "Empirical Surgery." This article provides comprehensive insights into our extensive research and exploration of the treatment modality known as "precision orthognathic surgery" over the years. We also present the technical system and application in"Ortho+X" treatment modality to offer valuable references and assistance to our colleagues in the field.
Orthognathic Surgery ; Orthognathic Surgical Procedures ; Printing, Three-Dimensional ; Surgery, Computer-Assisted

3D bioprinting technology is a rapidly developing technique that employs bioinks containing biological materials and living cells to construct biomedical products. However, 3D-printed tissues are static, while human tissues are in real-time dynamic states that can change in morphology and performance. To improve the compatibility between in vitro and in vivo environments, an in vitro tissue engineering technique that simulates this dynamic process is required. The concept of 4D printing, which combines "3D printing + time" provides a new approach to achieving this complex technique. 4D printing involves applying one or more smart materials that respond to stimuli, enabling them to change their shape, performance, and function under the corresponding stimulus to meet various needs. This article focuses on the latest research progress and potential application areas of 4D printing technology in the cardiovascular system, providing a theoretical and practical reference for the development of this technology.
Humans ; Tissue Engineering/methods* ; Bioprinting/methods* ; Printing, Three-Dimensional ; Cardiovascular System ; Tissue Scaffolds