Application Of Three-dimensional Printing Research Articles

Current and evolving applications of three-dimensional printing in forensic odontology: A review

In these digitized surroundings, we should not overlook the use of three-dimensional (3D) printing in forensic odontology, for investigative or court purposes, which is still comparatively new. We will use the term “3D printing” as it is widely recognized and will perhaps be the simplest phrase for the odontologist for daily use. Alternative terms are additive manufacturing and rapid prototyping. Today, 3D printing is most commonly used in dentistry for the manufacture of drill guides for dental implants, study models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopedic implants, and the fabrication of copings and frameworks for implant and dental restorations. However, we are yet to see forensic odontologists, lawyers, and expert witnesses appreciate embrace the advantages of 3D printing for its use in court of law. This may be due to a perception of it being complicated technology, high cost, or simply a lack of understanding of what can be done with 3D printing. 3D image capture devices minimize the amount of angular distortion, therefore such a system has the potential to create more robust forensic evidence for use in courts and medico-legal cases. The major application of 3D printing in forensic odontology includes bite mark analysis, 3D-computed tomography facial reconstruction, dental age estimation, sex determination, and physical models. The aim of this review article is to outline the use and possible benefits of 3D printing in forensic odontology.

Application of three-dimensional printing in the operation of distal tibia fracture involving epiphyseal plate injury for teenagers

To investigate the application value of three-dimensional (3-D) printing technology in the operation of distal tibia fracture involving epiphyseal plate injury for teenagers. The retrospective analysis was conducted on the clinical data of 16 cases of children patients with distal tibia fracture involving epiphyseal plate injury undergoing the operation by using of 3-D printing technology between January 2014 and December 2015. There were 12 males and 4 females with an age of 9-14 years (mean, 12.8 years). The causes of injury included traffic accident injury in 9 cases, heavy pound injury in 3 cases, and sport injury in 4 cases. The time from injury to operation was 3-92 hours (mean, 25.8 hours). According to Salter-Harris typing standard, the typing for epiphyseal injury was classified as type Ⅱ in 11 cases, type Ⅲ in 4 cases, and type Ⅳ in 1 case. The thin slice CT scan on the affected limb was performed before operation, and the Mimics14.0 medical software was applied for the design and the 1∶1 fracture model was printed by the 3-D printer; the stimulation of operative reduction was made in the fracture model, and bone plate, Kirschner wire, and hollow screw with the appropriate size were chosen, then the complete operative approach and method were designed and the internal fixator regimen was chosen, then the practical operation was performed based on the preoperative design regimen. The operation time was 40-68 minutes (mean, 59.1 minutes); the intraoperative blood loss was 5-102 mL (mean, 35 mL); the intraoperative fluoroscopy times was 2-6 times (mean, 2.8 times). All the patiens were followed up 12-24 months (mean, 15 months). The fracture of 15 cases reached anatomic reduction, and 1 cases had no anatomic reduction with the displaced end less than 1 mm. All the fractures reached bony union with the healing time of 2-4 months (mean, 2.6 months). There was no deep vein thrombosis, premature epiphyseal closure and oblique, or uneven ankle surface occurred, and there was no complication such as osteomyelitis, varus or valgus of ankle joint, joint stiffness, traumatic arthritis. Helfet scores of ankle function were measured at 12 months after operation, the results were excellent in 15 cases and good in 1 case. The angulation of introversion and extroversion for the affected limb was (6.56±2.48)°, and the growth length was (4.44±2.31) mm, and there was no significant difference ( t=0.086, P=0.932; t=0.392, P=0.697) when compared with the uninjured side [(6.50±1.51)°, (4.69±1.08) mm]. As the assistive technology, 3-D printing technology has a certain clinical application value in improving the effectiveness of distal tibia fracture involving epiphyseal plate injury.

Biomaterials for bone defect repair and bone regeneration

The treatment of large jaw bone defects remains an urgent clinical problem to be solved. With the development of biomaterials, stem cells and bone tissue engineering, new ideas and hopes for the regeneration of jaw have been offered. In addition to meeting the basic requirements of bone repair materials, scaffolds for the regeneration of large jaw bones require the ability of stem cells to participate in bone regeneration. Methods like optimization of scaffolds composition, design of porous structure and combination of gel and microsphere technology can enhance stem cell delivery in vivo, and the osteogenic differentiation of stem cells can be stimulated through controlled release of drugs, preparation of surface micron/nano topography and modifications of ionic components. Moreover, application of three-dimensional printing and channel structure in large-scale scaffolds fabrication present promising strategies for customized, accurate bone reconstruction and vascularization. It is only through synergistic optimization in all aspects that it is possible to obtain scaffold materials suitable for regeneration of large jaw bones. This article focuses on biological materials regulation, stem cell delivery, survival and differentiation, and their role in bone regeneration.

Minutes of Symposium on the Application of Three-Dimensional Printing in Stomatology

Minutes of Symposium on the Application of Three-Dimensional Printing in Stomatology

Abstract: Mandibular Reconstruction Using Cost-Effective Three-Dimensional Printing

INTRODUCTION: There has been an increasing interest in the applications of three-dimensional (3D) printing in plastic surgery.1,2 A physical 3D model provides visualization of complex defects that supersede digital imaging and can be used as a template for preoperative planning and surgical education.3,4With the advent of affordable quality and reliable printers, office-based 3D printing has become possible. We describe our experience with office-based 3D printing in the management of comminuted mandible fractures. The distorted topography of the bony surface and instability of fracture fragments can lead to suboptimal reduction, and shaping of the plate to contour the fracture can be challenging in the operating room. We used a 3D printed model of the patient’s mandible to bend plates preoperatively in order to achieve an ideal plate shape and thus optimum bony reduction. METHODS: Patients diagnosed with a comminuted mandible fracture at R Adams Cowley Shock Trauma Center were identified. Patient’s maxillofacial CT scan DICOM images were uploaded into 3D Slicer (www.slicer.org) and a 3D image model of the mandible was generated using a threshold segmentation technique. The model image was uploaded into Netfabb (Autodesk, San Rafael, CA) and the non-fractured side was mirrored to replace the comminuted side. The final model image was uploaded into Cura software (Ultimaker, Geldermalsen, Netherlands) and the 3D model was printed using a LulzBot TAZ 6 3D printer (Aleph Objects, Loveland, CO) and a 2 millimeter Polylactic acid filament. Titanium plates were then pre-bent according to the 3D printed mandible model and autoclaved in standard fashion prior to use in the operating room. Proper fracture reduction was evaluated with a postoperative CT scan. RESULTS: Three patients with comminuted mandible fractures had a 3D model of their mandible printed preoperatively. Average print time was 6 hours. Excluding the one-time cost of the 3D printer of $2,500, the average materials cost to print one mandible was $4.20. All three patients had successful placement of the titanium plates which were pre-bent preoperatively according to the 3D model. Postoperative CT imaging demonstrated adequate reduction in all three cases. CONCLUSION: Office-based three-dimensional printing is feasible and affordable. We demonstrated how 3D printed models of comminuted mandibular fractures can optimize fracture reduction by preoperatively bending plates. Reference Citations: 1. Choi JW, Kim N. Clinical application of three-dimensional printing technology in craniofacial plastic surgery. Arch Plast Surg. 2015;42(3):267–277. 2. Chae MP, Rozen WM, McMenamin PG, Findlay MW, Spychal RT, Hunter-Smith DJ. Emerging Applications of Bedside 3D Printing in Plastic Surgery. Front Surg. 2015;2(June):25. 3. Numajiri T, Nakamura H, Sowa Y, Nishino K. Low-cost Design and Manufacturing of Surgical Guides for Mandibular Reconstruction Using a Fibula. Plast Reconstr Surg - Glob Open. 2016;4(7):e805. 4. Lioufas PA, Quayle MR, Leong JC, McMenamin PG. 3D Printed Models of Cleft Palate Pathology for Surgical Education. Plast Reconstr surgery Glob open. 2016;4(9):e1029.

The Development and Applications of Three-Dimensional Printing

The Development and Applications of Three-Dimensional Printing

Study of Pinch-Off Locations during Drop-on-Demand Inkjet Printing of Viscoelastic Alginate Solutions.

The ligament pinch-off process of viscoelastic fluids during jetting is a key step in various biotechnology and dropwise three-dimensional printing applications. Various pinch-off locations have been investigated as a function of material properties and operating conditions during the drop-on-demand (DOD) inkjet printing of viscoelastic alginate solutions. Four breakup types are identified on the basis of the location of the first pinch-off position: front pinching is mainly governed by a balance of inertial and capillary effects, exit pinching is affected by the external actuation-induced hydrodynamic instability and mainly governed by a balance of elastic and capillary effects, middle pinching usually occurs any place along a uniform thin ligament under dominant viscous and elastic effects, and hybrid pinching happens when front pinching and exit pinching occur simultaneously as a special case.

Application of three-dimensional printing personalized acetabular wing-plate in treatment of complex acetabular fractures via lateral-rectus approach

Objective: To investigate reduction and fixation of complex acetabular fractures using three-dimensional (3D) printing technique and personalized acetabular wing-plate via lateral-rectus approach. Methods: From March to July 2016, 8 patients with complex acetabular fractures were surgically managed through 3D printing personalized acetabular wing-plate via lateral-rectus approach at Department of Orthopedics, the Third Affiliated Hospital of Southern Medical University. There were 4 male patients and 4 female patients, with an average age of 57 years (ranging from 31 to 76 years). According to Letournel-Judet classification, there were 2 anterior+ posterior hemitransverse fractures and 6 both-column fractures, without posterior wall fracture or contralateral pelvic fracture. The CT data files of acetabular fracture were imported into the computer and 3D printing technique was used to print the fractures models after reduction by digital orthopedic technique. The acetabular wing-plate was designed and printed with titanium. All fractures were treated via the lateral-rectus approach in a horizontal position after general anesthesia. The anterior column and the quadrilateral surface fractures were fixed by 3D printing personalized acetabular wing-plate, and the posterior column fractures were reduction and fixed by antegrade lag screws under direct vision. Results: All the 8 cases underwent the operation successfully. Postoperative X-ray and CT examination showed excellent or good reduction of anterior and posterior column, without any operation complications. Only 1 case with 75 years old was found screw loosening in the pubic bone with osteoporosis after 1 month's follow-up, who didn't accept any treatment because the patient didn't feel discomfort. According to the Matta radiological evaluation, the reduction of the acetabular fracture was rated as excellent in 3 cases, good in 4 cases and fair in 1 case. All patients were followed up for 3 to 6 months and all patients had achieved bone union. According to the modified Merle D'Aubigné and Postel scoring system, 5 cases were excellent, 2 cases were good, 1 case was fair. Conclusions: Surgical management of complex acetabular fracture via lateral-rectus approach combine with 3D printing personalized acetabular wing-plate can effectively improve reduction quality and fixation effect. It will be truly accurate, personalized and minimally invasive.

Preliminary Research on Mechanical Properties of 3D Printed Rock Structures

In this study, we explored the application of three-dimensional printing (3DP) simulated rock materials. Specimens were fabricated by two different formation methods (powder-ink binders (PIB) and selective laser sintering (SLS)). Uniaxial compression and splitting tensile tests were conducted on both printed specimens and weak rock specimens to compare the failure forms and mechanical properties. Generally, powder-ink binder specimens showed stronger mechanical properties than selective laser specimens, and specimens presented stronger mechanical properties when loaded parallel to the printing direction. The average compressive strength of SLS specimens was 3.88 ± 0.32 MPa and average tensile strength was 0.49 ± 0.05 MPa; the PIB specimens offered average compressive strength of about 9.82 ± 0.16 MPa and average tensile strength 0.85 ± 0.06 MPa, similar to sandstone specimens. PIB specimens printed vertical to the axial direction mechanical properties and failure forms as the weak rock specimens. Altogether, the results indicated that PIB specimens are optimal for simulating weak rock materials.

Clinical application of three-dimensional printing to the management of complex univentricular hearts with abnormal systemic or pulmonary venous drainage.

In recent years, three-dimensional printing has demonstrated reliable reproducibility of several organs including hearts with complex congenital cardiac anomalies. This represents the next step in advanced image processing and can be used to plan surgical repair. In this study, we describe three children with complex univentricular hearts and abnormal systemic or pulmonary venous drainage, in whom three-dimensional printed models based on CT data assisted with preoperative planning. For two children, after group discussion and examination of the models, a decision was made not to proceed with surgery. We extend the current clinical experience with three-dimensional printed modelling and discuss the benefits of such models in the setting of managing complex surgical problems in children with univentricular circulation and abnormal systemic or pulmonary venous drainage.

Three-Dimensional Printing for Percutaneous Endoscopic Thoracic Discectomy in Thoracic Disc Herniations: Case Report and Anatomy Review

Introduction: Thoracic disc herniations causing unrelenting neuralgia are relatively rare, especially cephalad to T-10 because the rib cage provides enough stability to offer relief with non-surgical methods over time. A transforaminal percutaneous endoscopic thoracic approach (PETD) however, is a feasible minimally invasive option for decompressing and removing the herniation without resorting to a more invasive and surgically more morbid open approach requiring thoracotomy and removal of the rib head through the thoracic cavity. Method: The application of three-dimensional printing of individualized anatomic models, improves the accuracy and safety of this less invasive percutaneous operation that allows for surgical performance under local anesthesia. With the data provided by preoperative three-dimensional reconstructive CT scans, an individualized 3-D thoracic model is established by using medical mimics’ software, produced with a 3-D laser printer. A more exact trajectory with a calculated skin entry point provides extra safety for a percutaneous postero-lateral approach. A 16-year-old male, with a thoracic disc herniation and unrelenting neuralgia, is diagnosed by CT scans and magnetic resonance imaging. Non-surgical methods failed to help his severe intercostal neuralgia. Following a preoperative evaluation, a percutaneous decompression was performed, aided by 3-D printing of the thoracic spine. PETD was performed under local anesthesia. Result: The patient had immediate resolution of his pre-operative radiating pain with no operative surgical morbidity. Extra safety is provided by operating with the patient awake. Conclusion: Thoracic disc herniations can be decompressed safely and effectively under local anesthesia by percutaneous endoscopic thoracic decompression (PETD). 3 D printing reconstructing the individual’s anatomy at the herniation level provides an additional method for trajectory guidance. Accuracy in a trans-foraminal approach for thoracic disc herniations is critical because of the close proximity of the spinal cord and the chest cavity.

Application of three-dimensional printing for colon targeted drug delivery systems.

Orally administered solid dosage forms currently dominate over all other dosage forms and routes of administrations. However, human gastrointestinal tract (GIT) poses a number of obstacles to delivery of the drugs to the site of interest and absorption in the GIT. Pharmaceutical scientists worldwide have been interested in colon drug delivery for several decades, not only for the delivery of the drugs for the treatment of colonic diseases such as ulcerative colitis and colon cancer but also for delivery of therapeutic proteins and peptides for systemic absorption. Despite extensive research in the area of colon targeted drug delivery, we have not been able to come up with an effective way of delivering drugs to the colon. The current tablets designed for colon drug release depend on either pH-dependent or time-delayed release formulations. During ulcerative colitis the gastric transit time and colon pH-levels is constantly changing depending on whether the patient is having a relapse or under remission. Hence, the current drug delivery system to the colon is based on one-size-fits-all. Fails to effectively deliver the drugs locally to the colon for colonic diseases and delivery of therapeutic proteins and peptides for systemic absorption from the colon. Hence, to overcome the current issues associated with colon drug delivery, we need to provide the patients with personalized tablets which are specifically designed to match the individual's gastric transit time depending on the disease state. Three-dimensional (3D) printing (3DP) technology is getting cheaper by the day and bespoke manufacturing of 3D-printed tablets could provide the solutions in the form of personalized colon drug delivery system. This review provides a bird's eye view of applications and current advances in pharmaceutical 3DP with emphasis on the development of colon targeted drug delivery systems.

Applications of Three-Dimensional Printing in Surgery.

Three-dimensional (3D) printing is a rapidly advancing technology in the field of surgery. This article reviews its contemporary applications in 3 aspects of surgery, namely, surgical planning, implants and prostheses, and education and training. Three-dimensional printing technology can contribute to surgical planning by depicting precise personalized anatomy and thus a potential improvement in surgical outcome. For implants and prosthesis, the technology might overcome the limitations of conventional methods such as visual discrepancy from the recipient's body and unmatching anatomy. In addition, 3D printing technology could be integrated into medical school curriculum, supplementing the conventional cadaver-based education and training in anatomy and surgery. Future potential applications of 3D printing in surgery, mainly in the areas of skin, nerve, and vascular graft preparation as well as ear reconstruction, are also discussed. Numerous trials and studies are still ongoing. However, scientists and clinicians are still encountering some limitations of the technology including high cost, long processing time, unsatisfactory mechanical properties, and suboptimal accuracy. These limitations might potentially hamper the applications of this technology in daily clinical practice.

SUITABILITY OF A SOUTH AFRICAN SILICA SAND FOR THREE-DIMENSIONAL PRINTING OF FOUNDRY MOULDS AND CORES

Applications of three-dimensional printing (3DP) to metal casting include, among other things, the direct manufacturing of foundry moulds and cores in refractory materials such as silica sand. The main properties of silica sand that are essentially related to the traditional moulding and core-making processes are: size distribution, clay content, pH, acid demand, and refractoriness. The silica sand used for 3DP must also be appropriately selected for the layer-based manufacturing process involved in 3DP. Properties such as grain size distribution, grain surface morphology, angularity, flowability, and recoating abilities have a particular importance when determining sand suitability. Because of these extra requirements, only a limited range of available foundry silica sands can be used for 3DP processes. The latter situation explains the scarcity and high cost of suitable silica sands, thus contributing to the relatively high operational costs of the 3DP processes for the production of sand moulds and cores. This research paper investigates the suitability of a locally-available silica sand for use in a Voxeljet VX1000 3DP machine. The local silica sand was assessed and compared with an imported silica sand recommended by the manufacturer of 3DP equipment in terms of foundry characteristics and recoating behaviour. The study shows that, despite the differences between the characteristics of the two silica sands, the local sand could be considered a suitable alternative to imported sand for rapid sand casting applications.

Recent advances in bioprinting techniques: approaches, applications and future prospects.

Bioprinting technology shows potential in tissue engineering for the fabrication of scaffolds, cells, tissues and organs reproducibly and with high accuracy. Bioprinting technologies are mainly divided into three categories, inkjet-based bioprinting, pressure-assisted bioprinting and laser-assisted bioprinting, based on their underlying printing principles. These various printing technologies have their advantages and limitations. Bioprinting utilizes biomaterials, cells or cell factors as a “bioink” to fabricate prospective tissue structures. Biomaterial parameters such as biocompatibility, cell viability and the cellular microenvironment strongly influence the printed product. Various printing technologies have been investigated, and great progress has been made in printing various types of tissue, including vasculature, heart, bone, cartilage, skin and liver. This review introduces basic principles and key aspects of some frequently used printing technologies. We focus on recent advances in three-dimensional printing applications, current challenges and future directions.

Application of three-dimensional printing to pavement texture effects on rubber friction

Despite the significant attention gained by the three-dimensional (3D) printing technology in many research fields, it has not yet found application in tyre–road friction and pavement engineering. To better understand the impact of different roughness length scales on rubber friction, the feasibility of utilising 3D printing for replicating pavement texture and the strength of this technology in creating customised roughness patterns are investigated. An image-stitching algorithm was developed for a common portable optical profiler in order to obtain a large topography of an asphalt specimen for friction experiments. The printed topography showed a replication efficacy down to 0.5 mm in wavelength. Printed samples with artificial surface patterns were then generated by random process theory and fractal modelling. Rubber sliding tests implied different frictional behaviour between the asphalt specimen and its printed replica, which was mainly attributed to severe wear of rubber on rougher asphalt specimen. For artificial geometries, friction increased as the Hurst exponent (H) increased. Results also suggested that reducing roll-off wavevector (q0), that is, increasing maximum aggregate size, reduces friction coefficient of a fractal surface.

Clinical application of three-dimensional printing in the personalized treatment of complex spinal disorders

PurposeTo investigate the usefulness of three-dimensional (3D) printing in complex spinal surgery. MethodsThe study was conducted from October 2014 to March 2015 in Shenzhen Second Peoples' Hospital and 4 cases of complex severe spinal disorders were selected from our department. Among them one patient combined with congenital scoliosis, one with atlas neoplasm, one with atlantoaxial dislocation, and the rest one with atlantoaxial fracture-dislocation. The data of the diseased region was collected from computerized tomography scans for 3D digital reconstruction and rapid prototyping to prepare photosensitive resin models, which were applied in the treatment of these cases. ResultsThe use of 3D models reduced operating time and intraoperative blood loss as well as the risk of postoperative complications. Furthermore, no pedicle penetrations or screw misplacement occurred according to the postoperative planar radiographic images. ConclusionThe tactile models from 3D printing allow direct observation and measurement, helping the orthopedists to have accurate morphometric information to provide personalized surgical planning and better communication with the patient and coworkers. Moreover, the photosensitive resin models can also guide the actual surgery with the drilling of pedicle screws and safe resection of tumor.

Hemodynamic Testing of Patient-Specific Mitral Valves Using a Pulse Duplicator: A Clinical Application of Three-Dimensional Printing.

To evaluate the feasibility of obtaining hemodynamic metrics of echocardiographically derived 3-dimensional printed mitral valve models deployed in a pulse-duplicator chamber. Exploratory study. Tertiary-care university hospital. Percutaneous MitraClip procedure patient. Three-dimensional R-wave gated, full-volume transesophageal echocardiography images were obtained after deployment of the MitraClip device. A high-quality diastolic frame of the mitral valve was segmented using Mimics Innovation Suite and merged with a flange. The data were exported as a stereolithography (.stl) file, and a rigid 3-dimensional model was printed using a MakerBot Replicator 2 printer. A flexible silicone cast then was created and deployed in the pulse-duplicator chamber filled with a blood-mimicking fluid. The authors were able to obtain continuous-wave Doppler tracings of the valve inflow with a transesophageal echocardiography transducer. They also were able to generate diastolic ventricular and atrial pressure tracings. Pressure half-time and mitral valve area were computed from these measurements. This pulse duplicator shows promising applications in hemodynamic testing of patient-specific anatomy. Future modifications to the system may allow for visualization and data collection of gradients across the aortic valve.

Application of three-dimensional printing in the resection of giant tumor of the thoracic cavity and the reconstruction surgery of chest wall

ABSTRACT Objective: To evaluate, the feasibility and efficacy of three-dimensional (3D) digital navigation, 3D design, and 3D printing in the surgical treatment of giant tumors in thoracic cavity. Patients and Methods: A 62-year-old male patient had a giant tumor in the left thoracic cavity. The tumor constricted the left lobe with the left chest wall being involved. We performed high-precision consecutive thin-sectional computed tomography (CT) scanning and obtained the 3D model of the tumor, lung, pulmonary, tracheobronchial tree, sternum, ribs, and costal cartilage with self-developed 3D image processing software. Before surgery, we also carried out digital navigation, printed out the tumor and the chest wall that is intended to be reconstructed, and developed the surgery program for the giant tumor. At the same time, 3D chest wall titanium was produced based on 3D printing. We performed giant tumor resection and sutured the titanium plate to the chest wall of the patient to repair the chest wall defect. After surgery, we performed CT scans and 3D reconstruction in order to determine the efficacy of surgical treatment. Results: The results showed that we successfully designed the repair surgery program for chest wall defect after the tumor resection. Titanium based on the 3D printing-assisted design completely fit the chest wall defect. Blood loss was significantly reduced compared to conventional titanium suture. There were fewer postoperative complications, and patient recovery was fast. Conclusion: We conclude that 3D printing-assisted resection of tumors in the thoracic cavity and chest wall reconstruction contributes to developing surgery program and performing complex thoracic surgery, which improves the efficacy of surgery, shortens the operation time, reduces the abrasion of conventional steel implant to the residual sternum, ribs, chest wall muscle and pleura, decreases the bleeding, abnormal breathing, and achieves the developmental shift to digital and personalized cardiothoracic surgery.

The medical application of three-dimensional printing

The medical application of three-dimensional printing