A novel approach for planning orthognathic surgery: The integration of dental casts into three-dimensional printed mandibular models

Three-dimensional (3D) printing in dental practice: Applications, areas of interest, and level of evidence

OBJECTIVES

The aim of this review to overview three-dimensional (3D) printing technologies available for different dental disciplines, considering the applicability of such technologies and materials development.

MATERIALS AND METHODS

Source Arksey and O'Malley's five stages framework using PubMed, EMBASE, and Scopus (Elsevier) databases managed this review. Papers focusing on 3D printing in dentistry and written in English were screened. Scientific productivity by the number of publications, areas of interest, and the focus of the investigations in each dental discipline were extracted.

RESULTS

Nine hundred thirty-four studies using 3D printing in dentistry were assessed. Limited clinical trials were observed, especially in Restorative, endodontics, and pediatric dentistry. Laboratory or animal studies are not reliable for clinical success, suggesting that clinical trials are a good approach to validate the new methods' outcomes and ensure that the benefits outweigh the risk. The most common application for 3D printing technologies is to facilitate conventional dental procedures.

CONCLUSIONS

The constantly improving quality of 3D printing applications has contributed to increasing the popularity of these technologies in dentistry; however, long-term clinical studies are necessary to assist in defining standards and endorsing the safe application of 3D printing in dental practice.

CLINICAL RELEVANCE

The recent progress in 3D materials has improved dental practice capabilities over the last decade. Understanding the current status of 3D printing in dentistry is essential to facilitate translating its applications from laboratory to the clinical setting.

Efficacy of Constructing Digital Hybrid Skull-Dentition Images Using an Intraoral Scanner and Cone-Beam Computed Tomography

Cone-beam computed tomography (CBCT) can distort dentition, and additional imaging is often required. A plaster model to help digitize dental images has been widely used in clinical practice, but there are some inconveniences such as complexity of the process and the risk of damage. The aim of this study was to evaluate the potential for improving dentition imaging with CBCT scans using an intraoral scanner instead of a plaster model. The study used laser model-scanned images of plaster models, imaging from two intraoral scanners, and CBCT images from 20 patients aged 12-18 years. CS 3600 (Carestream Dental, Atlanta, USA) and i700 (Medit, Seoul, Korea) were used as intraoral scanners. The full arch was scanned at once or in three sections using intraoral scanners. The segmented scans were merged to obtain full-arch images. With i700, full-arch images were additionally acquired using its "smart stich" function. The virtual skull-dentition hybrid images obtained from intraoral scanners were superimposed with images obtained using a plaster cast. The difference and distance of coordinate values at each reference point were measured. The average distances from the images obtained with the plaster cast were smaller than 0.39 mm, which is the voxel size of CBCT. Scanning the complete or partial arch using CS 3600 or i700 satisfactorily complemented the CBCT when compared to the plaster model. The virtual skull-dentition hybrid image obtained from intraoral scanners will be clinically useful, especially for patients and surgeons who have difficulty in scanning the complete arch at once.

Applications of three-dimensional printers in prosthetic dentistry

This narrative review aims to provide an overview of recent studies and case reports on three-dimensional (3D) printing, and to verify the applicability of 3D printers in the field of dental prostheses. This review was performed by conducting a search of PubMed. The clinical application of fabricating a prosthesis made with cobalt-chromium is considered possible depending on the material and hardware of the 3D printer. However, it is currently difficult to assess the clinical use of 3D-printed zirconia crowns. Further research is required, such as verification of materials used, margin morphology, and hardware. Clinically acceptable results have been reported for patterns using 3D printers. Interim restorations made using a 3D printer have been reported with good results that are considered clinically usable. Dentures made with 3D printers need further verification in terms of strength and deformation. Custom trays made with 3D printers are clinically useful, however, issues remain with design time and effort. Although several studies have reported the usefulness of 3D printers, further verification is required since 3D printers are still considered new technology.

Mixed reality and three dimensional printed models for resection of maxillary tumor: a case report

In the field of oral and maxillofacial surgery, many institutions have recently begun using three-dimensional printers to create three-dimensional models and mixed reality in a variety of diseases. Here, we report the actual situation model which we made using three-dimensional printer from virtual operation data and the resection that was performed while grasping a maxillary benign tumor and neighboring three-dimensional structure by designing an application for Microsoft® HoloLens, and using Mixed Reality surgery support during the procedure.

Accuracy of 3-Dimensionally Printed Full-Arch Dental Models: A Systematic Review

The use of additive manufacturing in dentistry has exponentially increased with dental model construction being the most common use of the technology. Henceforth, identifying the accuracy of additively manufactured dental models is critical. The objective of this study was to systematically review the literature and evaluate the accuracy of full-arch dental models manufactured using different 3D printing technologies. Seven databases were searched, and 2209 articles initially identified of which twenty-eight studies fulfilling the inclusion criteria were analysed. A meta-analysis was not possible due to unclear reporting and heterogeneity of studies. Stereolithography (SLA) was the most investigated technology, followed by digital light processing (DLP). Accuracy of 3D printed models varied widely between <100 to >500 μm with the majority of models deemed of clinically acceptable accuracy. The smallest (3.3 μm) and largest (579 μm) mean errors were produced by SLA printers. For DLP, majority of investigated printers (n = 6/8) produced models with <100 μm accuracy. Manufacturing parameters, including layer thickness, base design, postprocessing and storage, significantly influenced the model’s accuracy. Majority of studies supported the use of 3D printed dental models. Nonetheless, models deemed clinically acceptable for orthodontic purposes may not necessarily be acceptable for the prosthodontic workflow or applications requiring high accuracy.

Orthodontic-surgical treatment for a patient with Class II malocclusion and inadequate maxillary incisor inclination

Dental health and patient satisfaction at the end of orthodontic treatment are needed if the treatment is to be considered successful. This case report highlights the importance of proper diagnosis for a patient initially treated with camouflage, despite the indications for surgery. A 16-year-old male patient sought treatment complaining about his appearance. He had been using an appliance for 6 years without improvement. He had a convex profile, an enlarged lower third of the face, reduced cervical-mandibular line, and Class II molar relationship. The maxillary incisors had excessive buccal root torque, throbbing pain, and dental mobility, with no visible bone coverage in the tomographic sections. The cephalometric analysis confirmed the skeletal Class II relationship (ANB, 11.6°; Wits appraisal, 14.2 mm) because of severe mandibular deficiency (SNB, 71.2°), aggravated by the vertical growth tendency (FMA, 27.3°). Changes in IMPA (108.1°) and U1-NA (0.9°; -2.9 mm) reflected the previous orthodontic attempt to compensate for the malocclusion. After periodontal and endodontic evaluation, a new treatment plan was developed. The incisors would be positioned in their bone bases, the mandibular first premolars would be extracted to create space for the second molars and increase the overjet, and the patient would be referred for orthognathic surgery. The patient was satisfied with the esthetic and functional results of this treatment.

Maxillary reconstruction using tunneling flap technique with 3D custom-made titanium mesh plate and particulate cancellous bone and marrow graft: a case report

Background

Reconstructive surgery is often required for tumors of the oral and maxillofacial region, irrespective of whether they are benign or malignant, the area involved, and the tumor size. Recently, three-dimensional (3D) models are increasingly used in reconstructive surgery. However, these models have rarely been adapted for the fabrication of custom-made reconstruction materials. In this report, we present a case of maxillary reconstruction using a laboratory-engineered, custom-made mesh plate from a 3D model.

Case presentation

The patient was a 56-year-old female, who had undergone maxillary resection in 2011 for intraoral squamous cell carcinoma that presented as a swelling of the anterior maxillary gingiva. Five years later, there was no recurrence of the malignant tumor and a maxillary reconstruction was planned. Computed tomography (CT) revealed a large bony defect in the dental-alveolar area of the anterior maxilla. Using the CT data, a 3D model of the maxilla was prepared, and the site of reconstruction determined. A custom-made mesh plate was fabricated using the 3D model (Okada Medical Supply, Tokyo, Japan). We performed the reconstruction using the custom-made titanium mesh plate and the particulate cancellous bone and marrow graft from her iliac bone. We employed the tunneling flap technique without alveolar crest incision, to prevent surgical wound dehiscence, mesh exposure, and alveolar bone loss. Ten months later, three dental implants were inserted in the graft. Before the final crown setting, we performed a gingivoplasty with palate mucosal graft. The patient has expressed total satisfaction with both the functional and esthetic outcomes of the procedure.

Conclusion

We have successfully performed a maxillary and dental reconstruction using a custom-made, pre-bent titanium mesh plate.

Creation of a multidisciplinary and multicenter study group for the use of 3D printing in general thoracic surgery: lessons learned in our first year experience

Introduction: In recent years, the use of 3D printing in medicine has grown exponentially, but the use of 3D technology has not been equally adopted by the different medical specialties. Published 3D printing activity in general thoracic surgery is scarce and has been mostly limited to case reports. The aim of this report was to reflect on the results and lessons learned from a newly created multidisciplinary and multicenter 3D unit of the Spanish Society of Thoracic Surgery (SECT). Methods: This is a pilot study to determine the feasibility and usefulness of printing 3D models for patients with thoracic malignancy or airway complications, based on real data. We designed a point-of-care 3D printing workflow involving thoracic surgeons, radiologists with experience in intrathoracic pathology, and engineers with experience in additive manufacturing. Results: In the first year of operation we generated 26 three-dimensional models out of 27 cases received (96.3%). In 9 cases a virtual model was sufficient for optimal patient handling, while in 17 cases a 3D model was printed. Per pathology, cases were classified as airway stenosis after lung transplantation (7 cases, 25.9%), tracheal pathology (7 cases, 25.9%), chest tumors (6 cases, 22.2%) carcinoid tumors (4 cases, 14.8%), mediastinal tumors (2 cases, 7.4%) and Pancoast tumors (one case, 3.7%). Conclusion: A multidisciplinary 3D laboratory is feasible in a hospital setting, and working as a multicenter group increases the number of cases and diversity of pathologies thus providing further opportunity to study the benefits of the 3D printing technology in general thoracic surgery.

Three-Dimensional Printed Polylactic Acid Scaffolds Promote Bone-like Matrix Deposition in Vitro

Large bone defects represent a significant challenge for clinicians and surgeons. Tissue engineering for bone regeneration represents an innovative solution for this dilemma and may yield attractive alternate bone substitutes. Three-dimensional (3D) printing with inexpensive desktop printers shows promise in generating high-resolution structures mimicking native tissues using biocompatible, biodegradable, and cost-effective thermoplastics, which are already FDA-approved for food use, drug delivery, and many medical devices. Microporous 3D-printed polylactic acid scaffolds, with different pore sizes (500, 750, and 1000 μm), were designed and manufactured using an inexpensive desktop 3D printer, and the mechanical properties were assessed. The scaffolds were compared for cell growth, activity, and bone-like tissue formation using primary human osteoblasts. Osteoblasts showed high proliferation, metabolic activity, and osteogenic matrix protein production, in which 750 μm pore-size scaffolds showed superiority. Further experimentation using human mesenchymal stem cells on 750 μm pore scaffolds showed their ability in supporting osteogenic differentiation. These findings suggest that even in the absence of any surface modifications, low-cost 750 μm pore-size 3D-printed scaffolds may be suitable as a bone substitute for repair of large bone defects.

Anterior Lumbar Interbody Fusion Using a Personalized Approach: Is Custom the Future of Implants for Anterior Lumbar Interbody Fusion Surgery?

BACKGROUND

Spine surgery has the potential to benefit from the use of three-dimensional (3D) printing technology (additive manufacturing), particularly in cases of complex anatomic diseases. Custom devices have the potential to reduce operative times, reduce blood loss, provide immediate stability, and improve fusion rates.

CASE DESCRIPTION

A 34-year-old man presented with 3-year history of bilateral L5 radiculopathy caused by bilateral L5 pars defect, L5/S1 degenerative disc disease, and severe foraminal stenosis. Anterior lumbar interbody fusion surgery was determined to be the most efficacious method for distraction of the disc space to increase the foraminal volume and stabilization of the motion segment. Surgical decompression and reconstruction was performed in combination with a 3D printed custom interbody implant. Custom design features included corrective angulation to restore lumbar lordosis, preplanned screw holes in the 3D implant, and device end plate interface geometry designed to shape-match with the patient's end plate anatomy.

CONCLUSIONS

The use of patient-specific implants has reduced operative time significantly, which may offset costs of increased time spent preplanning the procedure. Surgical procedures can be preplanned using 3D models reconstructed from patient computed tomography and/or magnetic resonance imaging scans. Planning can be aided by 3D printed models of patient anatomy, which surgeons can use in training before performing complex procedures. When considering implants and prostheses, the use of 3D printing allows a superior anatomic fit for the patient compared with generic devices, with the potential to improve restoration of nonpathologic anatomy.

Novel condylar repositioning method for 3D-printed models

Background

Along with the advances in technology of three-dimensional (3D) printer, it became a possible to make more precise patient-specific 3D model in the various fields including oral and maxillofacial surgery. When creating 3D models of the mandible and maxilla, it is easier to make a single unit with a fused temporomandibular joint, though this results in poor operability of the model. However, while models created with a separate mandible and maxilla have operability, it can be difficult to fully restore the position of the condylar after simulation. The purpose of this study is to introduce and asses the novel condylar repositioning method in 3D model preoperational simulation.

Methods

Our novel condylar repositioning method is simple to apply two irregularities in 3D models. Three oral surgeons measured and evaluated one linear distance and two angles in 3D models.

Results

This study included two patients who underwent sagittal split ramus osteotomy (SSRO) and two benign tumor patients who underwent segmental mandibulectomy and immediate reconstruction. For each SSRO case, the mandibular condyles were designed to be convex and the glenoid cavities were designed to be concave. For the benign tumor cases, the margins on the resection side, including the joint portions, were designed to be convex, and the resection margin was designed to be concave. The distance from the mandibular ramus to the tip of the maxillary canine, the angle created by joining the inferior edge of the orbit to the tip of the maxillary canine and the ramus, the angle created by the lines from the base of the mentum to the endpoint of the condyle, and the angle between the most lateral point of the condyle and the most medial point of the condyle were measured before and after simulations. Near-complete matches were observed for all items measured before and after model simulations of surgery in all jaw deformity and reconstruction cases.

Conclusions

We demonstrated that 3D models manufactured using our method can be applied to simulations and fully restore the position of the condyle without the need for special devices.

L5 En-Bloc Vertebrectomy with Customized Reconstructive Implant: Comparison of Patient-Specific Versus Off-the-Shelf Implant

BACKGROUND

Spine surgery has the potential to benefit from additive manufacturing/3-dimensional printing (3DP) technology with complex anatomical pathologies requiring reconstruction, with the potential to customize surgery to reduce operative times, reduce blood loss, provide immediate stability, and potentially improve fusion rates. We report a unique case of intraoperative trial placement of a custom patient-specific implant (PSI) versus the final implantation of a customizable off-the-shelf (OTS) implant. Data collected for comparison included time to implant, ease of implantation, firmness of press-fit, and fixation options after implantation.

CASE DESCRIPTION

A 64-year-old man presented with low back pain. Computed tomography and magnetic resonance imaging revealed a solitary lesion in the L5 vertebral body, confirmed by positron emission tomography scan. Removal of the L5 vertebral body was performed, and reconstruction was achieved with an expandable cage. The time of implant insertion was minimal with the PSI (90 seconds) versus the OTS (>40 minutes). Immediate press-fit and "firmness" of implantation was clearly superior with the PSI, although this was an intraoperative subjective assessment. Other benefits include integral fixation that is predetermined with the PSI, reduced time and blood loss, and ease of bone grafting with a PSI.

CONCLUSIONS

Use of 3DP has been able to reduce operative time significantly. Surgeons can train before performing complex procedures, which enhances their presurgical planning, with the goal to maximize patient outcomes. When considering implants and prostheses, the use of 3DP allows a superior anatomical fit for the patient, with the potential to improve restoration of anatomy.

Methodology for Stress Measurement by Transparent Dental Aligners using Strain Gauge

Aim

Orthodontic tooth movement is a pressing issue nowadays. An increased esthetic demand during orthodontic treatment has resulted in several alternative treatments. However, the need to avoid conventional fixed orthodontic prosthesis has led to the usage of computer-aided scanning, imaging, and printing technology along with the emergence of transparent dental aligners. The motive of this study is to present methodology of measurement of the stress applied by transparent dental aligners on human teeth using a strain gauge-based measurement device.

Materials and methods

Three dimensional (3D) scanner, 3D printer, thermoforming machine, strain gauge, data acquisition device, 3Shape Ortho Analyzer software were used.

Results

For a full-bridge Wheatstone bridge data acquisition system (DAQ), a standard aligner can strain a constantan-based strain gauge by nearly 2.5 × 10—4. This is based on the strain gauge factor of 2, input voltage 5 V for which a change in voltage of 2.5 mV was detected. Young's modulus for constantan strain gauge is given as 17.5 MPa; hence, this produced a stress of nearly 4.38 × 10—3 MPa.

Conclusion

This article describes an effective and convenient methodology for orthodontic treatment design for patients with crowding problem using computer-aided design (CAD) and computer-aided manufacturing (CAM) software and, thereafter, printing different stages of maxilla and mandible using fused deposition modeling (FDM) rapid prototyping technique. A transparent aligner is fabricated using thermoforming process, and the applied stresses on manipulated teeth by aligner can be evaluated using a strain gauge-based DAQ.

Clinical significance

This approach is expected to understand the efficacy of the thermoformed aligners for teeth movements by calculating applied forces and stresses.

How to cite this article

Bajaj D, Madhav I, Juneja M, Tuli R, Jindal P. Methodology for Stress Measurement by Transparent Dental Aligners using Strain Gauge. World J Dent 2018;9(1):13-18.

An ad hoc three dimensionally printed tool facilitates intraesophageal suturing in experimental surgery

BACKGROUND

Three-dimensional printing (3DP) has become popular for development of anatomic models, preoperative planning, and production of tailored implants. A novel laparoscopic, transgastric procedure for distal esophageal mucosectomy was developed. During this procedure, a space holder had to be introduced into the distal esophagus for exposure during suturing. The production process and evaluation of a 3DP space holder are described herein.

MATERIALS AND METHODS

Computer-aided design software was used to develop models printed from polylactic acid. The prototype was adapted after testing in a cadaveric model. Subsequently, the device was evaluated in a nonsurvival porcine model. A mucosal purse-string suture was placed as orally as possible in the esophagus, in the intervention group with and in the control group without use of the tool (n = 8 each). The distance of the stitches from the Z-line was measured. The variability of stitches indicated the suture quality.

RESULTS

The median maximum distance from the Z-line to purse-string suture was larger in the intervention group (5.0 [3.3-6.4] versus 2.4 [2.0-4.1] cm; P = 0.013). The time taken to place the sutures was shorter in the control group (P < 0.001). Stitch variance tended to be greater in the intervention group (2.3 [0.9-2.5] versus 0.7 [0.2-0.4] cm; P = 0.051). The time required for design and production of a tailored tool was less than 24 h.

CONCLUSIONS

3DP in experimental surgery enables rapid production, permits repeated adaptation until a tailored tool is obtained, and ensures independence from industrial partners. With the aid of the space holder more orally located esophageal lesions came within reach.

Integration of digital dental casts in cone beam computed tomography scans-a clinical validation study

OBJECTIVES

Images derived from cone beam computed tomography (CBCT) scans lack detailed information on the dentition and interocclusal relationships needed for proper surgical planning and production of surgical splints. To get a proper representation of the dentition, integration of a digital dental model into the CBCT scan is necessary. The aim of this study was to validate a simplified protocol to integrate digital dental models into CBCT scans using only one scan.

MATERIALS AND METHODS

Conventional protocol A used one combined upper and lower impression and two CBCT scans. The new protocol B included placement of ten markers on the gingiva, one CBCT scan, and two separate impressions of the upper and lower dentition. Twenty consecutive patients, scheduled for mandibular advancement surgery, were included. To validate protocol B, 3-dimensional reconstructions were made, which were compared by calculating the mean intersurface distances obtained with both protocols.

RESULTS

The mean distance for all patients for the upper jaw is 0.39 mm and for the lower jaw is 0.30 mm. For ten out of 20 patients, all distances were less than 1 mm. For the other ten patients, all distances were less than 2 mm.

CONCLUSIONS

Mean distances of 0.39 and 0.30 mm are clinically acceptable and comparable to other studies; therefore, this new protocol is clinically accurate.

CLINICAL RELEVANCE

This new protocol seems to be clinically accurate. It is less time consuming, gives less radiation exposure for the patient, and has a lower risk for positional errors of the impressions compared to other integration protocols.

Three-dimensional printing in contemporary fixed prosthodontics: A technique article

Digital dentistry has gained in popularity among clinicians and laboratory technicians because of its versatile applications. Three-dimensional (3D) printing has been applied in many areas of dentistry as it offers efficiency, affordability, accessibility, reproducibility, speed, and accuracy. This article describes a technique where 3D printing is used to fabricate a die-trimmed cast and to replicate gingival tissue and implant analogs. The digital workflow that replaces the conventional laboratory procedure is outlined.

Advances in 3D Modeling: Preoperative Templating for Revision Wrist Surgery

BACKGROUND

Three-dimensional (3D) printing is a computer-directed process leading to the layered synthesis of scaled models. The popularity and availability of the technique has exponentially increased over the last decade, and as such is seeing a greater number of medical and surgical applications.

METHODS

We report 3 cases involving the use of 3D printing as an aid to operative planning in the revision of wrist surgery.

RESULTS

All patients underwent successful operative interventions with a £34 average cost of model creation.

CONCLUSIONS

A growing number of reports are emerging in reconstructive surgical specialities including maxillofacial, orthopedic, and plastic surgery; from our experience, we advocate the economically viable use of 3D printing for preoperative templating.

[Application of 3D printing and computer-assisted surgical simulation in preoperative planning for acetabular fracture]

OBJECTIVE

To evaluate the feasibility and effectiveness of using 3D printing and computer-assisted surgical simulation in preoperative planning for acetabular fractures.

METHODS

A retrospective analysis was performed in 53 patients with pelvic fracture, who underwent surgical treatment between September, 2013 and December, 2015 with complete follow-up data. Among them, 19 patients were treated with CT three-dimensional reconstruction, computer-assisted virtual reset internal fixation, 3D model printing, and personalized surgery simulation before surgery (3D group), and 34 patients underwent routine preoperative examination (conventional group). The intraoperative blood loss, transfusion volume, times of intraoperative X-ray, operation time, Matta score and Merle D' Aubigne & Postel score were recorded in the 2 groups. Preoperative planning and postoperative outcomes in the two groups were compared.

RESULTS

All the operations were completed successfully. In 3D group, significantly less intraoperative blood loss, transfusion volume, fewer times of X-ray, and shortened operation time were recorded compared with those in the conventional group (P<0.05). According to the Matta scores, excellent or good fracture reduction was achieved in 94.7% (18/19) of the patients in 3D group and in 82.4% (28/34) of the patients in conventional group; the rates of excellent and good hip function at the final follow-up were 89.5% (17/19) in the 3D group and 85.3% (29/34) in the conventional group (P>0.05). In the 3D group, the actual internal fixation well matched the preoperative design.

CONCLUSIONS

3D printing and computer-assisted surgical simulation for preoperative planning is feasible and accurate for management of acetabular fracture and can effectively improve the operation efficiency.

Three-Dimensional Printing: Custom-Made Implants for Craniomaxillofacial Reconstructive Surgery

Craniomaxillofacial reconstructive surgery is a challenging field. First it aims to restore primary functions and second to preserve craniofacial anatomical features like symmetry and harmony. Three-dimensional (3D) printed biomodels have been widely adopted in medical fields by providing tactile feedback and a superior appreciation of visuospatial relationship between anatomical structures. Craniomaxillofacial reconstructive surgery was one of the first areas to implement 3D printing technology in their practice. Biomodeling has been used in craniofacial reconstruction of traumatic injuries, congenital disorders, tumor removal, iatrogenic injuries (e.g., decompressive craniectomies), orthognathic surgery, and implantology. 3D printing has proven to improve and enable an optimization of preoperative planning, develop intraoperative guidance tools, reduce operative time, and significantly improve the biofunctional and the aesthetic outcome. This technology has also shown great potential in enriching the teaching of medical students and surgical residents. The aim of this review is to present the current status of 3D printing technology and its practical and innovative applications, specifically in craniomaxillofacial reconstructive surgery, illustrated with two clinical cases where the 3D printing technology was successfully used.

Three dimensional printing: A review on the utility within medicine and otolaryngology

Three dimensional (3D) printing is a novel technique that has evolved over the past 35 years and has the potential to revolutionize the field of medicine with its inherent advantages of customizability and the ability to create complex shapes with precision. It has been used extensively within the fields of orthopedics, dentistry, and craniofacial reconstruction with wide ranging utility including, medical modeling, surgical planning and the production of custom plates, screws and surgical guides. Furthermore, it has been used for similar means in the field of Otorhinolaryngology and also has potential to revolutionize the treatment of airway malacia. In fact, 3D printed external tracheal splints have already been studied in several pediatric patients with very promising results. The emerging field of 3D bioprinting, which integrates tissue engineering with 3D printing, may produce a paradigm shift with the potential introduction of customized functional biologic replacements.

A rapid and intelligent designing technique for patient-specific and 3D-printed orthopedic cast

Background

Two point four out of 100 people suffer from one or more fractures in the course of average lifetimes. Traditional casts are featured as cumbersome structures that result in high risk of cutaneous complications. Clinical demands for developing a hygienic cast have gotten more and more attention. 3D printing technique is rapidly growing in the fabrication of custom-made rehabilitation tools. The objective of this study is to develop a rapid and intelligent modeling technique for developing patient-specific and hygienic orthopedic casts produced by 3D printing technologies.

Results

A cast model is firstly created from a patient’s image to develop patient-specific features. A unique technique to creating geometric reference has been developed to perform detail modeling cast. The cast is modeled as funnel-shaped geometry to create smooth edges to prevent bruises from mild movements of injured limbs. Surface pattern includes ventilation structure and opening gap for hygienic purpose and wearing comfort. The cast can be adjusted to accommodate swelling from injured limbs during treatment. Finite element analysis (FEA) is employed to validate the mechanical performance of the cast structure and identify potential risk of the structural collapse due to concentrated stresses. The cast is fabricated by 3D printing technology using approval material.

Conclusions

The 3D-printed prototype is featured as super lightweight with 1/10 of weight in compared with traditional alternatives. Medical technicians with few experiences can design cast within 20 min using the proposed technique. The image-based design minimizes the distortion during healing process because of the best fit geometry. The highly ventilated structure develops hygienic benefits on reducing the risk of cutaneous complications and potentially improve treatment efficacy and increase patients’ satisfactions.

The "Pure Marriage" between 3D Printing and Well-Ordered Nanoarrays by Using PEALD Assisted Hydrothermal Surface Engineering

For the first time, homogeneous and well-ordered functional nanoarrays were grown densely on the complex structured three-dimensional (3D) printing frameworks through a general plasma enhanced atomic layer deposition (PEALD) assisted hydrothermal surface engineering process. The entire process was free from toxic additives or harmful residues and, therefore, can meet the critical requirements of high-purity products. As a practical example, 3D customized earplugs were precisely manufactured according to the model of ear canals at the 0.1 mm level. Meanwhile, well-ordered ZnO nanoarrays, formed on the surfaces of these 3D printed earplugs, could effectively prevent the growth of five main pathogens derived from the patients with otitis media and exhibited excellent wear resistance as well. On the basis of both animal experiments and volunteers' investigations, the 3D customized earplugs showed sound insulation capabilities superior to those of traditional earplugs. Further animal experiments demonstrated the potential of as-modified implant scaffolds in practical clinical applications. This work, exemplified with earplugs and implant scaffolds, oriented the development direction of 3D printing in biomedical devices, which precisely integrated customized architecture and tailored surface performance.

Three-dimensional printing: review of application in medicine and hepatic surgery

Three-dimensional (3D) printing (3DP) is a rapid prototyping technology that has gained increasing recognition in many different fields. Inherent accuracy and low-cost property enable applicability of 3DP in many areas, such as manufacturing, aerospace, medical, and industrial design. Recently, 3DP has gained considerable attention in the medical field. The image data can be quickly turned into physical objects by using 3DP technology. These objects are being used across a variety of surgical specialties. The shortage of cadaver specimens is a major problem in medical education. However, this concern has been solved with the emergence of 3DP model. Custom-made items can be produced by using 3DP technology. This innovation allows 3DP use in preoperative planning and surgical training. Learning is difficult among medical students because of the complex anatomical structures of the liver. Thus, 3D visualization is a useful tool in anatomy teaching and hepatic surgical training. However, conventional models do not capture haptic qualities. 3DP can produce highly accurate and complex physical models. Many types of human or animal differentiated cells can be printed successfully with the development of 3D bio-printing technology. This progress represents a valuable breakthrough that exhibits many potential uses, such as research on drug metabolism or liver disease mechanism. This technology can also be used to solve shortage of organs for transplant in the future.

Three-dimensional printing in surgery: a review of current surgical applications

BACKGROUND

Three-dimensional printing (3DP) is gaining increasing recognition as a technique that will transform the landscape of surgical practice. It allows for the rapid conversion of anatomic images into physical objects, which are being used across a variety of surgical specialties. It has been unclear which groups are leading the way in coming up with novel ways of using the technology and what specifically the technology is being used for. The aim of this article was to review the current applications of 3DP in modern surgical practice.

MATERIALS AND METHODS

An electronic search was carried out in MEDLINE, EMBASE, and PsycINFO for terms related to 3DP. These were then screened for relevance and practical applications of the technology in surgery.

RESULTS

Four hundred eighty-eight articles were initially found, and these were eventually narrowed down to 93 full-text articles. It was determined that there were three main areas in which the technology is being used to print: (1) anatomic models, (2) surgical instruments, and (3) implants and prostheses.

CONCLUSIONS

Different specialties are at different stages in the use of the technology. The costs involved with implementing the technology and time taken for printing are important factors to consider before widespread use. For the foreseeable future, this is an exciting and interesting technology with the capacity to radically change health care and revolutionize modern surgery.

Rapid prototyping-assisted maxillofacial reconstruction

Rapid prototyping (RP) technologies have found many uses in dentistry, and especially oral and maxillofacial surgery, due to its ability to promote product development while at the same time reducing cost and depositing a part of any degree of complexity theoretically. This paper provides an overview of RP technologies for maxillofacial reconstruction covering both fundamentals and applications of the technologies. Key fundamentals of RP technologies involving the history, characteristics, and principles are reviewed. A number of RP applications to the main fields of oral and maxillofacial surgery, including restoration of maxillofacial deformities and defects, reduction of functional bone tissues, correction of dento-maxillofacial deformities, and fabrication of maxillofacial prostheses, are discussed. The most remarkable challenges for development of RP-assisted maxillofacial surgery and promising solutions are also elaborated.