Dimensional Accuracy in 3D Printed Medical Models: A Follow-Up Study on SLA and SLS Technology.

Background: With the rise of new 3D printers, assessing accuracy is crucial for obtaining the best results in patient care. Previous studies have shown that the highest accuracy is achieved with SLS printing technology; however, SLA printing technology has made significant improvements in recent years. Methods: In this study, a realistic anatomical model of a mandible and skull, a cutting guide for mandibular osteotomy, and a splint for orthognathic surgery were replicated five times each using two different 3D printing technologies: SLA and SLS. Results: The SLA group had a median trueness RMS value of 0.148 mm and a precision RMS value of 0.117 mm. The SLS group had a median trueness RMS value of 0.144 mm and a precision RMS value of 0.096 mm. There was no statistically significant difference in RMS values between SLS and SLA technologies regarding trueness. Regarding precision, however, the RMS values for SLS technology were significantly lower in the splint and cutting guide applications than those printed with SLA technology. Conclusions: Both 3D printing technologies produce modern models and applications with equally high dimensional accuracy. Considering current cost pressures experienced by hospitals, the lower-cost SLA 3D printer is a reliable choice for point-of-care 3D printing.

Fully digital occlusion planning in orthognathic surgery - A crossover study.

Orthognathic surgery enables patients with severe jaw malocclusions to normalise their chewing function and, as such, to improve their quality of life. Over the last few years, digitalisation has been set in motion by intraoral scanners and the improvement of planning software in the field of oral and maxillofacial surgery. Previous studies based on plaster cast models showed that the virtual occlusion based on digitally scanned models can be comparable to conventional methods. This retrospective crossover study aimed to prove that the virtual occlusion finding with the IPS CaseDesigner® (version 2.3.5.2, KLS Martin, Tuttlingen, Germany) is accurate enough to use intraoral scans exclusively. MATERIALS AND METHODS: A total of 23 orthognathic surgery patients receiving an intraoral scan for their treatment were included in this study. Two experienced maxillofacial surgeons haptically performed the occlusion finding on three-dimensional (3D) stereolithographic models using the fully digital pathway. One surgeon repeated the procedure a second time to evaluate intra-observer variability. The study aimed to show the difference between these two planning methods by upholding the surgical accuracy of less than 2 mm in translation and 2° in rotation. The conventional haptic occlusion was set as a reference throughout the whole study. The data were tested with a one-sample Wilcoxon test for the fit into the surgical accuracy. RESULTS: The difference between the virtual and conventional groups was significantly smaller than the surgical accuracy (all p < 0.001). Both translational movements (anterior/posterior (median 0.51 mm [0.28, 0.88]), left/right (median 0.46 mm [0.20, 0.87]), cranial/caudal (median 0.37 mm [0.11, 0.69])) and rotations (Roll (median 0.71° [0.29, 1.35]), Pitch (median 0.72° [0.29, 1.44]), Yaw (median 1.09° [0.33, 1.60])) were in the range of surgical accuracy (2 mm/2°). The most significant differences were found in the anterior/posterior translation (median 0.51 mm [0.28, 0.88]) and the Yaw rotation (median 1.09° [0.33, 1.60]). CONCLUSION: These results demonstrate that the entirely virtual workflow in orthognathic surgery, including intraoral scanning and the virtual semi-automatic occlusion finding, represents a reliable and state-of-the-art alternative to the conventional haptic method.

Intraosseous myofibroma mimicking an odontogenic lesion: case report, literature review, and differential diagnosis.

BACKGROUND: Intraosseous myofibroma of the jaw is a rare neoplasm of mesenchymal origin with limited comprehensive understanding. It typically affects patients in the first two decades of life with a male predilection. CASE PRESENTATION: This study presents a rare case of myofibroma mimicking an odontogenic lesion in a 2-year-old boy. The patient presented with an incidental finding of a painless swelling of the right mandibular ramus of unknown etiology. Imaging analysis revealed a solid, expansile lesion adjacent to the germinal zone of the right mandibular first molar. Histopathologic analysis and immunohistochemistry after incisional biopsy suggested a possible central odontogenic fibroma, and the patient underwent total enucleation, leading to the final diagnosis of intraosseous myofibroma. Follow-up examinations showed no evidence of recurrence. CONCLUSIONS: This report contributes to the understanding of myofibroma in pediatric patients and underscores the critical role of meticulous histopathologic examination for effective surgical planning and optimal patient outcomes.

Evaluation of the Dimensional Accuracy of Robot-Guided Laser Osteotomy in Reconstruction with Patient-Specific Implants-An Accuracy Study of Digital High-Tech Procedures.

Background/Objective: With the rapid advancement in surgical technologies, new workflows for mandibular reconstruction are constantly being evaluated. Cutting guides are extensively employed for defining osteotomy planes but are prone to errors during fabrication and positioning. A virtually defined osteotomy plane and drilling holes in robotic surgery minimize potential sources of error and yield highly accurate outcomes. Methods: Ten mandibular replicas were evaluated after cutting-guided saw osteotomy and robot-guided laser osteotomy following reconstruction with patient-specific implants. The descriptive data analysis summarizes the mean, standard deviation (SD), median, minimum, maximum, and root mean square (RMS) values of the surface comparison for 3D printed models regarding trueness and precision. Results: The saw group had a median trueness RMS value of 2.0 mm (SD ± 1.7) and a precision of 1.6 mm (SD ± 1.4). The laser group had a median trueness RMS value of 1.2 mm (SD ± 1.1) and an equal precision of 1.6 mm (SD ± 1.4). These results indicate that robot-guided laser osteotomies have a comparable accuracy to cutting-guided saw osteotomies, even though there was a lack of statistical significance. Conclusions: Despite the limited sample size, this digital high-tech procedure has been shown to be potentially equivalent to the conventional osteotomy method. Robotic surgery and laser osteotomy offers enormous advantages, as they enable the seamless integration of precise virtual preoperative planning and exact execution in the human body, eliminating the need for surgical guides in the future.

An Algorithm for Jaw Pain among Divers.

Background: Temporomandibular disease (TMD) is commonly seen, and divers also experience pain in the temporomandibular joint (TMJ) or masticatory muscles. This article aims to provide a tool for diving physicians or medical professionals involved in diving medicine since jaw pain among divers is a pertinent subject and can be challenging to evaluate without some background in dentistry or maxillofacial surgery. Method: A basic algorithm was developed to provide a tool to differentiate jaw pains experienced by divers. Three brief case studies were developed, and five diving physicians were tasked with diagnosing the cases using the algorithm. Additionally, simple exercises and massage techniques that can benefit patients with TMD, particularly immediately after diving, are outlined. Results: All five diving physicians successfully diagnosed the cases using the algorithm. However, three of them were unable to diagnose the first case (disc luxation) without consulting the algorithm. Nevertheless, all physicians acknowledged the utility of the algorithm. Conclusions: Jaw pain in divers can stem from diverse causes, but effective treatment options exist. Our study findings provide valuable insights to assist diving physicians in making accurate diagnoses and guiding appropriate patient management, which may include referrals to specialists such as dentists, maxillofacial surgeons, or orthodontists.

Cleft lip and palate surgery simulator: Open source simulation model.

Objective: Cleft lip and palate is the most common craniofacial birth anomaly and requires surgery in the first year of life. However, craniofacial surgery training opportunities are limited. The aim of this study was to present and evaluate an open-source cleft lip and palate hybrid (casting and three-dimensional (3D) printing) simulation model which can be replicated at low cost to facilitate the teaching and training of cleft surgery anatomy and techniques. Design: The soft tissue component of the cleft surgery training model was casted using a 3D printed 5-component mold and silicone. The bony structure was designed to simulate the facial anatomy and to hold the silicone soft tissue. Setting: Two groups, one group of trainees and one group of expert surgeons, at University Hospital Basel in Switzerland and Pontifical Catholic University of Chile in Santiago, Chile, tested the cleft lip and palate simulation model. Participants completed a Likert-based face and content validity questionnaire to assess the realism of the model and its usefulness in surgical training. Results: More than 70 % of the participants agreed that the model accurately simulated human tissues found in patients with unilateral cleft lip and palate. Over 60 % of the participants also agreed that the model realistically replicated surgical procedures. In addition, 80-90 % of the participants found the model to be a useful and appropriate tool for teaching the anatomy and surgical techniques involved in performing unilateral cleft lip and palate repair. Conclusion: This open-source protocol provides a cost-effective solution for surgeons to introduce the cleft morphology and surgical techniques to trainees on a regular basis. It addresses the current financial barrier that limits access to commercially available models during the early stages of surgeon training prior to specialization in the field.

Patient-specific implants made of 3D printed bioresorbable polymers at the point-of-care: material, technology, and scope of surgical application.

BACKGROUND: Bioresorbable patient-specific additive-manufactured bone grafts, meshes, and plates are emerging as a promising alternative that can overcome the challenges associated with conventional off-the-shelf implants. The fabrication of patient-specific implants (PSIs) directly at the point-of-care (POC), such as hospitals, clinics, and surgical centers, allows for more flexible, faster, and more efficient processes, reducing the need for outsourcing to external manufacturers. We want to emphasize the potential advantages of producing bioresorbable polymer implants for cranio-maxillofacial surgery at the POC by highlighting its surgical applications, benefits, and limitations. METHODS: This study describes the workflow of designing and fabricating degradable polymeric PSIs using three-dimensional (3D) printing technology. The cortical bone was segmented from the patient's computed tomography data using Materialise Mimics software, and the PSIs were designed created using Geomagic Freeform and nTopology software. The implants were finally printed via Arburg Plastic Freeforming (APF) of medical-grade poly (L-lactide-co-D, L-lactide) with 30% ß-tricalcium phosphate and evaluated for fit. RESULTS: 3D printed implants using APF technology showed surfaces with highly uniform and well-connected droplets with minimal gap formation between the printed paths. For the plates and meshes, a wall thickness down to 0.8 mm could be achieved. In this study, we successfully printed plates for osteosynthesis, implants for orbital floor fractures, meshes for alveolar bone regeneration, and bone scaffolds with interconnected channels. CONCLUSIONS: This study shows the feasibility of using 3D printing to create degradable polymeric PSIs seamlessly integrated into virtual surgical planning workflows. Implementing POC 3D printing of biodegradable PSI can potentially improve therapeutic outcomes, but regulatory compliance must be addressed.

Virtual Surgical Planning and Customized CAD/CAM Cranial Implants: Preoperative and Intraoperative Strategies for Temporal Intraosseous Meningioma Resection.

Primary intraosseous meningioma (PIM) is a rare subtype of extradural meningiomas, with the indication for surgical resection in most cases. With an increasing demand for efficient workflows with optimal functional and cosmetical results, techniques for bone reconstruction after resection are developing rapidly. The authors present 2 cases with one-stage cranioplasty after resection of PIM, using 3D technology for preplanned patient-specific implants. In the first case, a premanufactured patient-specific PEEK implant was used for reconstruction; in the second case, a 3-dimensional (3D)-based premanufactured silicon mold was used to produce a customized PMMA implant intraoperatively. Both techniques enabled the surgeons to achieve optimal intraoperative fit of the implant after craniectomy, leading to satisfying functional and cosmetic results. The use of 3D technology, such as Computer-Aided Design and Computer-Aided Manufacturing (CAD/CAM) for the production of patient-specific implants can optimize 1-stage cranioplasty after PIM resection.

Precision Surgery for Orbital Cavernous Hemangiomas: The Role of Three-Dimensional Printing in Individualized Resection-An Educational Experience.

Orbital cavernous hemangiomas are the most common primary orbital tumors in adults, providing challenges for optimal surgical approach planning within an anatomically complex area with close proximity to vital neurovascular structures. The authors present an individualized lateral mini-orbitozygomatic approach for the resection of an orbital cavernous haemangioma based on a preoperative 3-dimensional-printed model. This individualized approach enabled the surgeons to achieve optimal exposure while maintaining safety during the resection of the lesion, but also to respect the patient's physiognomy and hairline. In addition, the model was used for patient informed consent, helping the patient understand the procedure. Although adding additional effort to preoperative planning, 3-dimensional model-based approaches can offer great benefits when it comes to customizing surgical approaches, especially for anatomically challenging resections.

Three-Dimensional Printable Open-Source Cleft Lip and Palate Impression Trays: A Single-Impression Workflow.

SUMMARY: Documenting complex three-dimensional (3D) cleft lip and palate malformation with plaster casts based on maxillary impressions is standard care. Presurgical orthopedic treatment also requires an impression. Digital impression-taking in patients with cleft lip and palate is feasible, but procurement costs hinder clinical implementation. Individualized impression trays allow for a precise impression, limiting airway risk. The authors present an open-source impression tray library with scalable impression trays not requiring 3D modeling knowledge. The cleft lip and palate impression tray library is accessible on Open Science Framework. Different shapes are available, and the tray size is selected based on the tuber distance. This allows 3D printing with biocompatible material at the point of care complying with local regulations. The open-source cleft tray library presented offers a hybrid solution for cleft centers, pending the implementation of digital impression.

Finite element analysis of low-profile reconstruction plates for atrophic mandibles: a comparison of novel 3D grid and conventional plate designs.

OBJECTIVES: This study aimed to compare the reconstruction with type 2.4 and three-dimensional (3D) grid plates relating the areas of weakness to anatomical regions of force incidence in atrophic mandibles with and without segmentation using finite element analysis (FEA). MATERIALS AND METHODS: Strength and force quality in the mandible were also determined. The atrophic mandible models with and without segmentation were divided into four groups, and the behavior of each plate was analyzed using finite element analysis. In the atrophic mandible without segmentation using the type 2.4 reconstruction plate, the highest stress concentration in the plate was observed in the posterior region of the mandibular body and in the grid type 3D reconstruction plate was observed in the mandibular angle. RESULTS: In the segmented atrophic mandible with the 2.4 reconstruction plate, higher stress concentration was observed in the mandibular segment defect. Analysis of the 3D grid-like reconstruction plate revealed that the geometry of the plate conferred greater stiffness to the assembly, as the most significant stress concentration was observed at the mandibular angle. CONCLUSION: The width of the plate design may influence the strength, not the thickness.

Is the Pre-Shaping of an Orbital Implant on a Patient-Specific 3D-Printed Model Advantageous Compared to Conventional Free-Hand Shaping? A Systematic Review and Meta-Analysis.

This study aimed to perform a systematic review and meta-analysis to compare pre-shaped implants on a patient-specific 3D-printed (3DP) model to manual free-hand shaping (MFS) for orbital wall reconstruction. The PRISMA protocol was followed in this study, and the review was registered in the PROSPERO database (CRD42021261594). A search was conducted in MEDLINE (PubMed), Embase, Cochrane Library, Clinicaltrials.gov, Google Scholar, and the grey literature. Ten articles were included, and six outcomes were analyzed. In total, 281 patients were in the 3DP group and 283 were in the MFS group. The studies had an overall high risk of bias. 3DP models resulted in a better accuracy of fit, anatomical angle reproduction, and defect area coverage. The correction of orbital volume was also superior with statistical significance. There was a higher percentage of the correction of enophthalmos and diplopia in the 3DP group. Intraoperative bleeding and hospital stay were reduced in the 3DP group. The meta-analysis of operative time showed a reduction in the average operative time by 23.58 min (95% CI: -43.98 to -3.19), which was statistically significant (t(6) = -2.8299, p = 0.0300). The 3DP models appear advantageous for an accurate orbital wall reconstruction, with fewer complications than those for conventional free-hand-shaped implants.

Comparison of Artificial Intelligence-Based Applications for Mandible Segmentation: From Established Platforms to In-House-Developed Software.

Medical image segmentation, whether semi-automatically or manually, is labor-intensive, subjective, and needs specialized personnel. The fully automated segmentation process recently gained importance due to its better design and understanding of CNNs. Considering this, we decided to develop our in-house segmentation software and compare it to the systems of established companies, an inexperienced user, and an expert as ground truth. The companies included in the study have a cloud-based option that performs accurately in clinical routine (dice similarity coefficient of 0.912 to 0.949) with an average segmentation time ranging from 3'54″ to 85'54″. Our in-house model achieved an accuracy of 94.24% compared to the best-performing software and had the shortest mean segmentation time of 2'03″. During the study, developing in-house segmentation software gave us a glimpse into the strenuous work that companies face when offering clinically relevant solutions. All the problems encountered were discussed with the companies and solved, so both parties benefited from this experience. In doing so, we demonstrated that fully automated segmentation needs further research and collaboration between academics and the private sector to achieve full acceptance in clinical routines.

Dental and Maxillofacial Emergency Algorithms in Swiss Emergency Departments.

This study aimed to evaluate the availability and use of dental and maxillofacial emergency algorithms in Swiss hospitals. A survey was performed among physicians at Swiss emergency departments (ED) and participants of the "36th Annual Meeting of the Society for Oral and Cranio-Maxillofacial Surgery". Eighty-nine EDs in Switzerland were questioned about the availability and use of electronic algorithms in their hospitals. Eighty-one (91%) participated in the study. In 75 (93%) of the EDs, electronic algorithms are used, mainly "medStandards". Six have no available algorithms. Fifty-two (64%) use algorithms daily. Eight (10%) Swiss EDs have maxillofacial and dental algorithms, and 73 (90%) have no access to or do not know about them. For dental algorithms, 28 (38%) of the respondents would like to have access, and 16 (22%) do not desire access. For maxillofacial algorithms, 23 (32%) want to have access and 21 (29%) do not want it. Most (74%) of the participating maxillofacial surgeons did not know about the existence of ED algorithms regarding their specialty. Our study shows that the existence of specific algorithms is often not known. Furthermore, there is a demand for dental and maxillofacial algorithms in Swiss EDs.

Clinical and patient-reported outcome after patient-specific 3D printer-assisted cranioplasty.

Various cranioplasty techniques exist for the reconstruction of cranial bone defects. Patient-specific implants can be produced in-house using a recently developed 3D printer-assisted cranioplasty technique. However, the resulting cosmetic outcomes from the patient's perspective are underreported. With our case series, we aim to present the clinical outcome, morbidity rate, patient-reported cosmetic results, and cost-effectiveness of patient-specific3D printer-assisted cranioplasty technique. This is a consecutive retrospective case series of adult patients undergoing cranioplasty using the patient-specific 3D printer-assisted technique. As primary endpoint, the functional outcome based on modified Rankin scale (mRS) at discharge and follow-up was assessed. A prospective telephone survey was conducted to collect and provide patient-reported outcomes. Thirty-one patients underwent patient-specific 3D printer-assisted cranioplasty, mostly to reconstruct frontotemporoparietal (61.3%) and frontotemporal defects with orbital involvement (19.4%). Good functional outcome (mRS ≤ 2) at discharge and during the last follow-up was achieved in 54.8% (n = 17) and 58.1% (n = 18) patients. Overall, the rate of clinically relevant surgery-related complications was 35.5% (n = 11). Postoperative epidural hematoma/collection (16.1%) and infections (12.9%) were the most frequent complications. Permanent morbidity occurred in one patient (3.2%) with postoperative acute ipsilateral vision loss after frontotemporal cranioplasty with orbital involvement. No surgery-related mortality occurred. The mean patient-reported cosmetic satisfaction score was 7.8 ± 1.5, with 80% of patients reporting satisfying or very satisfying cosmetic results. No significant differences were seen between the different defect localization regarding the cosmetic outcome. The mean manufacturing costs of a patient-specific 3D printer-assisted implant ranged from 748 to 1129 USD. Based on our case series, patient-specific 3D printer-assisted cranioplasty is cost-effective and leads to satisfying cosmetic results, especially in large defects and/or defects with complex geometry.

Medication-Related Osteonecrosis of the Jaw: A Cross-Sectional Survey among Urologists in Switzerland, Germany, and Austria.

Medication-related osteonecrosis of the jaw (MRONJ) is a potentially preventable adverse side effect of mainly antiresorptive drugs. MRONJ is expected to become a growing clinical problem due to the aging population and the increasing number of patients requiring antiresorptive agents. Knowledge and awareness about MRONJ and elimination of the oral and dental risk factors before starting antiresorptive therapy (AR) are fundamental to reducing the incidence of MRONJ. In urology, ARs are used primarily in patients suffering from bone metastases due to prostate cancer and to prevent cancer-treatment-induced bone loss (CTIBL) in prostate cancer patients receiving endocrine therapy. This postal survey aimed to evaluate disease-related knowledge and awareness about implementing oral examinations for patients starting AR among Swiss, German, and Austrian urologists. A total of 176 urologists returned the completed questionnaire, yielding a response rate of 11.7%. Of the respondents, 44.9% (n = 79) and 24.4% (n = 43) stated that they give more than five first-time prescriptions of denosumab and of intravenous or oral bisphosphonates per year, respectively. Only 14.8% (n = 26) of the participating urologists had never encountered MRONJ cases related to BPs. Of the participants, 89.8% (n = 158) had implemented referrals to dentists for oral examination before initiating AR. The mean percentage of correct answers regarding the knowledge about MRONJ was 70.9% ± 11.2%. In contrast to previous surveys on MRONJ among physicians, this study showed that the participating urologists were sufficiently informed about MRONJ, as reflected by the high number of participants implementing preventive dental screenings.

Distance mapping in three-dimensional virtual surgical planning in hand, wrist and forearm surgery: a tool to avoid mistakes.

PURPOSE: Three-dimensional planning in corrective surgeries in the hand and wrist has become popular throughout the last 20 years. Imaging technologies and software have improved since their first description in the late 1980s. New imaging technologies, such as distance mapping (DM), improve the safety of virtual surgical planning (VSP) and help to avoid mistakes. We describe the effective use of DM in two representative and frequently performed surgical interventions (radius malunion and scaphoid pseudoarthrosis). METHODS: We simulated surgical intervention in both cases using DM. Joint spaces were quantitatively and qualitatively displayed in a colour-coded fashion, which allowed the estimation of cartilage thickness and joint space congruency. These parameters are presented in the virtual surgical planning pre- and postoperatively as well as in the actual situation in our cases. RESULTS: DM had a high impact on the VSP, especially in radius corrective osteotomy, where we changed the surgical plan due to the visualization of the planned postoperative situation. The actual postoperative situation was also documented using DM, which allowed for comparison of the VSP and the achieved postoperative situation. Both patients were successfully treated, and bone healing and clinical improvement were achieved. CONCLUSION: The use of colour-coded static or dynamic distance mapping is useful for virtual surgical planning of corrective osteotomies of the hand, wrist and forearm. It also allows confirmation of the correct patient treatment and assessment of the follow-up radiological documentation.

Point-of-Care Virtual Surgical Planning and 3D Printing in Oral and Cranio-Maxillofacial Surgery: A Narrative Review.

This paper provides an overview on the use of virtual surgical planning (VSP) and point-of-care 3D printing (POC 3DP) in oral and cranio-maxillofacial (CMF) surgery based on a literature review. The authors searched PubMed, Web of Science, and Embase to find papers published between January 2015 and February 2022 in English, which describe human applications of POC 3DP in CMF surgery, resulting in 63 articles being included. The main review findings were as follows: most used clinical applications were anatomical models and cutting guides; production took place in-house or as "in-house-outsourced" workflows; the surgeon alone was involved in POC 3DP in 36 papers; the use of free versus paid planning software was balanced (50.72% vs. 49.27%); average planning time was 4.44 h; overall operating time decreased and outcomes were favorable, though evidence-based studies were limited; and finally, the heterogenous cost reports made a comprehensive financial analysis difficult. Overall, the development of in-house 3D printed devices supports CMF surgery, and encouraging results indicate that the technology has matured considerably.

Cold ablation robot-guided laser osteotomy in hand, wrist and forearm surgery-A feasibility study.

INTRODUCTION: Traditional bone surgery using saws and chisels is associated with direct contact of instruments with the bone causing friction, heat and pressure and hence, damaging the bone and the surrounding soft tissues. METHOD: Cold ablation laser osteotomy offers new possibilities to perform corrective osteotomies in the field of bone surgery. We introduce the technology of navigated cold ablation robot-guided laser osteotomy, present potential applications, and preliminary pre-clinical cadaver test results in the field of hand-, wrist- and forearm surgery. RESULTS: The cadaver tests showed first promising results for corrections in all planes and axes using different cutting patterns. CONCLUSION: Cold ablation laser osteotomy seems to be a feasible new method to perform osteotomies in the field of hand-, wrist- and forearm surgery. Primary osseous stability could be achieved using various cutting patterns which could lead to reduction of the amount of hardware required for osteosynthesis. Further tests are required to proof the latter and precision.