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 examine the clinical efficacy of myectomy guided by personalized three-dimensional reconstruction and printing for patients with obstructive hypertrophic cardiomyopathy. Methods: The clinical data of 28 patients with obstructive hypertrophic cardiomyopathy, who underwent septal myectomy guided by personalized three-dimensional reconstruction and printing in the Department of Cardiaovascular Surgery, Guangdong Provincial People's Hospital from May 2020 to December 2021, were retrospectively analyzed. There were 14 males and 14 females, aging (51.1±14.0) years (range: 18 to 72 years). Enhanced cardiac computed tomography images were imported into Mimics software for preoperative three-dimensional reconstruction. The direction of the short axial plane of each segment was marked perpendicularly to the interventricular septum on the long axial plane of the digital cardiac model, then the thickness was measured on each short axial plane. A figurative digital model was used to determine the extent of resection and to visualize mitral valve and papillary muscle abnormalities. Correlation between the length, width, thickness, and volume of the predicted resected myocardium and those of the surgically resected myocardium was assessed by Pearson correlation analysis or Spearman correlation analysis. The accuracy of detecting mitral valve and papillary muscle abnormalities of transthoracic echocardiography and three-dimensional reconstruction was also compared. Results: There was no death or serious complications like permanent pacemaker implantation, re-sternotomy for bleeding, low cardiac output syndrome, stroke, or multiple organ dysfunction syndromes in the whole group. Namely, the obstruction of the left ventricular outflow tract was effectively relieved. The systolic anterior motion of the anterior mitral valve leaflet was absent in all patients after myectomy. The length, width, and thickness of the predicted resected myocardium by three-dimensional reconstruction were significantly positively correlated with the length (R=0.65, 95%CI: 0.37 to 0.82, P<0.01), width (R=0.39, 95%CI: 0.02 to 0.67, P<0.01), and thickness (R=0.82, 95%CI: 0.65 to 0.92, P<0.01) of the surgically resected myocardium, while the relation of the volume of the predicted resected myocardium and the volume of the surgically resected myocardium was a strong positive correlation (R=0.88, 95%CI: 0.76 to 0.94, P<0.01). Importantly, the interventricular septal myocardial thickness measured by preoperative transthoracic echocardiography showed a moderate positive correlation with the volume of surgically resected myocardium (R=0.52, 95%CI: 0.19 to 0.75, P<0.01). During a follow-up of (14.4±6.8) months (range: 3 to 22 months), no death occurred, and 1 patient was readmitted for endocardial radiofrequency ablation due to atrial fibrillation. Conclusion: Personalized three-dimensional reconstruction and printing can not only visualize the intracardiac structure but also guide septal myectomy by predicting the thickness, volume, and extent of resected myocardium to achieve ideal resection.
Female ; Humans ; Male ; Cardiomyopathy, Hypertrophic/diagnosis* ; Imaging, Three-Dimensional ; Printing, Three-Dimensional ; Retrospective Studies ; Treatment Outcome ; Ventricular Septum ; Adolescent ; Young Adult ; Adult ; Middle Aged ; Aged

Dental dysplasia are abnormalities in teeth structure, morphology, number and eruption caused by genetic and environmental factors during dental development. Digital medical techniques, as the current hot spot of medical research, bring great challenges and opportunities to modern stomatology. The applications of digital techniques, such as digital diagnosis method, digital virtual simulated design, three-dimensional printing, static and dynamic guidance and artificial intelligence, can provide a more accurate, efficient, automatic and intelligent modern concepts and patterns for epidemiology, diagnosis, multidisciplinary treatment and outcome assessment of dental developmental anomalies.
Artificial Intelligence ; Printing, Three-Dimensional ; Tooth

OBJECTIVE: To investigate the application of 3D printing percutaneous surgical guide plate in closed reduction and cannulated screw internal fixation of femoral neck fracture. METHODS: The clinical data of 12 patients with femoral neck fracture from March 2019 to March 2022 were retrospectively analyzed. Patients were divided into observation group and control group according to different operation plans, with 6 cases in each group. The observation group received percutaneous operation guide plate assisted closed reduction and hollow screw internal fixation, while the control group received closed reduction and hollow compression screw internal fixation. The operation time, intraoperative blood loss, fluoroscopy times, and Kirschner needle puncture times were compared between two groups. The location of screws were recordedon postoperative X-ray films, follow-up time, time of complete fracture healing, Harris score of hip joint and the incidence of complications were recorded on postoperative X-ray films. RESULTS: The operation time of observation group (32.17±6.18) min was shorter than that of control group (53.83±7.31) min (P<0.05). The amount of intraoperative bleeding in the observation group (18.33±2.94) ml was less than that in the control group (38.17±5.56) ml(P<0.05). The times of fluoroscopy in the observation group (7.50±1.05) were less than those in the control group (21.00±4.82) (P<0.05). The number of Kirschner needle punctures (8.00±0.63) in observation group was less than that in control group (32.67±3.08) (P<0.05). The follow-up time was(12.88±0.74) months in observation group and (12.83±0.72) months in control group, there was no significant difference between two groups (P>0.05). One year after operation, Harris score of hip joint in the observation group was(82.00±4.52) points, while that in the control group was(81.00±3.41) points, there was no significant difference between two groups(P>0.05). The time of complete fracture healing in the observation group was (7.50±1.05) months, while that in the control group was (7.67±1.21) months, there was no significant difference between two groups(P>0.05). The parallelism of the screws in the observation group was (0.50±0.11) ° and (0.76±0.15) °, which were lower than that in the control group (1.57±0.31) ° and (1.87±0.21) ° (P<0.05). The screw distribution area ratio (0.13±0.02) cm2 in the observation group was higher than that in the control group (0.08±0.01) cm2 (P<0.05). No complications such as necrosis of femoral head, nonunion of fracture, shortening of femoral neck and withdrawal of internal fixation occurred in both groups. CONCLUSION The application of 3D printing percutaneous surgical guide plate improves the accuracy and safety of closed reduction and cannulated screw internal fixation for femoral neck fracture. It has the advantages of minimally invasive, reducing radiation exposure, fast and accurate, shortening the operation time and reducing intraoperative bleeding.
Humans ; Retrospective Studies ; Treatment Outcome ; Femoral Neck Fractures/surgery* ; Fracture Fixation, Internal ; Bone Screws ; Printing, Three-Dimensional

OBJECTIVE: To investigate whether 3D-printed artificial vertebral body can reduce prosthesis subsidence rate for patients with cervical chordomas, through comparing the rates of prosthesis subsidence between 3D printing artificial vertebral body and titanium mesh for anterior spinal reconstruction after total spondylectomy. METHODS: This was a retrospective analysis of patients who underwent surgical treatment for cervical chordoma at our hospital from March 2005 to September 2019. There were nine patients in the group of 3D artificial vertebral body (3D group), and 15 patients in the group of titanium mesh cage (Mesh group). The patients' characteristics and treatment data were extracted from the medical records, including age, gender, CT hounsfield unit of cervical vertebra and surgical information, such as the surgical segments, time and blood loss of surgery, frequency and degree of prosthesis subsidence after surgery. Radiographic observations of prosthesis subsidence during the follow-up, including X-rays, CT, and magnetic resonance imaging were also collected. SPSS 22.0 was used to analysis the data. RESULTS: There was no significant difference between the two groups in gender, age, CT hounsfield unit, surgical segments, time of surgery, blood loss of posterior surgery and total blood loss. Blood loss of anterior surgery was 700 (300, 825) mL in 3D group and 1 500 (750, 2 800) mL in Mesh group (P < 0.05). The prosthesis subsidence during the follow-up, 3 months after surgery, there was significant difference between the two groups in mild prosthesis subsidence (P < 0.05). The vertebral height of the 3D group decreased less than 1 mm in eight cases (no prosthesis subsidence) and more than 1 mm in one case (mild prosthesis subsidence). The vertebral height of the Mesh group decreased less than 1 mm in five cases (no prosthesis subsidence), and more than 1 mm in eight cases (mild prosthesis subsidence). Two patients did not have X-rays in 3 months after surgery. There was a statistically significant difference between the two groups in the prosthesis subsidence rate at the end of 12 months (P < 0.01). The vertebral height of eight cases in the 3D group decreased less than 1 mm (no prosthesis subsidence) and one case more than 3 mm (severe prosthesis subsidence). Four of the 15 cases in the Mesh group decreased less than 1 mm (no prosthesis subsidence), two cases more than 1 mm (mild prosthesis subsidence), and nine cases more than 3 mm (severe prosthesis subsidence). There was a statistically significant difference between the two groups in the prosthesis subsidence rate at the end of 24 months (P < 0.01). The vertebral height of seven cases in the 3D group decreased less than 1 mm (no prosthesis subsidence), one case more than 3 mm (severe prosthesis subsidence), and one case died with tumor. One case in the Mesh group decreased less than 1 mm (no prosthesis subsidence), one case more than 1 mm (mild prosthesis subsidence), 11 case more than 3 mm (severe prosthesis subsidence), one case died with tumor and one lost the follow-up. Moreover, at the end of 12 months and 24 months, there was significant difference between the two groups in severe prosthesis subsidence rate (P < 0.01). CONCLUSION 3D-printed artificial vertebral body for anterior spinal reconstruction after total spondylectomy for patients with cervical chordoma can provide reliable spinal stability, and reduce the incidence of prosthesis subsidence after 2-year follow-up.
Humans ; Chordoma/surgery* ; Retrospective Studies ; Vertebral Body ; Titanium ; Cervical Vertebrae/surgery* ; Printing, Three-Dimensional ; Spinal Fusion/methods* ; Treatment Outcome

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

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