From Theory to Tech

To explore a novel method for fabricating removable partial dentures (RPDs) using polyetheretherketone (PEEK) by computer-aided design and computer-aided manufacturing (CAD/CAM) technologies and to evaluate their fits for different assemblies in vitro. A standard stone cast of mandibular partial edentulous jaw was scanned using a lab scanner. Based on the digital cast, thirteen complete RPDs were designed combing dental CAD software and reverse engineering software, and then fabricated using PEEK by milling machine. Fits of assemblies were evaluated quantitatively by measuring the spaces between RPDs and casts. The gaps between RPDs and stone casts in different assemblies were duplicated using light-body silicone impression material and then measured using three-dimensional (3D) digital analysis methods in virtue of a dedicated software. Statistically, one-way analysis of variance (ANOVA) was used to compare the difference of gaps among assemblies in different shapes such as occlusal rest, denture base, and major connector. Paired-samples t test was used to compare the gaps difference for the similar shape assemblies in different areas. One-piece PEEK RPDs were successfully designed and fabricated by CAD/CAM, and all the RPDs were well-seated on stone casts. The gaps between occlusal rests and casts [(84.3±23.6) μm] were significantly larger than those of denture bases [(32.5±27.8) μm] and major connectors [(49.9±47.0) μm], which meant that the fits of denture bases and major connectors were better than that of occlusal rests. However, the fits of all assemblies could be accepted clinically. For the similar shape assemblies in different areas, there were no significantly differences for gaps between distal extension denture bases [(25.1±55.3) μm] and non-extensive denture bases [(41.5±17.7) μm]. The gaps of occlusal rests adjacent and nonadjacent to the edentulous space were (86.1±29.8) μm and (80.8±42.1) μm respectively and there were no significantly difference between them either. These results implied that different locations had no apparent effect on the fits of assemblies. With the computer-aided design and computer-aided manufacturing technology, PEEK can be used to fabricate one-piece removable partial dentures. And all assemblies of the one-piece PEEK RPDs showed satisfying fits in vitro, indicating a promising clinical application in the future.

The research aims to identify and apply computer-aided design and Manufacturing technology and its impact on improving product quality and rationalizing costs. The research also aims to spread awareness among departments and workers of the company in question about the importance of computer-aided design and Manufacturing technology and urging them to shift design from manual to computer-aided design. Here, the importance of research emerged because of the flexibility that computer-aided design and Manufacturing technology provideded in formulating, designing and producing the product, and here a problem arose. Researching the necessity of shifting design and production to automated technologies to improve product quality and rationalize cost and time by reducing the number of workers, increasing their efficiency and effectively utilizing information.

Due to the absence of agile characteristics, many traditional products have been struggling to face the onslaught of intensive competition. Agile characteristics would enable a product to be reconfigured quickly in response to the customers' dynamic demands. One of the theoretical propositions is that, computer-aided design (CAD)/computer-aided manufacturing (CAM) technology possesses the capabilities to infuse agile characteristics in the traditional products. To examine this theoretical proposition, the research work being reported in this paper was carried out. During this research, the pump was chosen as a candidate of traditional product. The impeller and casing of the pump were subsequently modelled using CAD technology and design equations. Subsequently, four impeller and casing models were evolved. To examine the manufacturing aspect of these models, CAM technology was used. This research outcome indicated the feasibility of converting a traditional product into an agile compatible product using CAD/CAM technology.

Simple SummaryThe health-related quality of life was evaluated in 23 patients undergoing mandibular reconstruction with free fibula flap and titanium customized plates. A computer-aided design and computer-aided manufacturing technology were used. The University of Washington Quality of Life questionnaire for head and neck cancer patients is a widely used and validated tool, which was self-completed by the patients after 12 months of surgery. In the 12 single question domains, the highest scores were obtained in the domains of taste, shoulder function, anxiety, and pain. The lowest scores corresponded to chewing, appearance, saliva, and mood. The global quality of life was rated as good, very good, or outstanding by 81% of patients. The present results compared favorably with previous studies of mandibular reconstruction using the same questionnaire published in literature.A single-center retrospective study was conducted to assess health-related quality of life (HRQoL) in 23 consecutive patients undergoing mandibular reconstruction using the computer-aided design (CAD) and computer-aided manufacturing (CAM) technology, free fibula flap, and titanium patient-specific implants (PSIs). HRQoL was evaluated after at least 12 months of surgery using the University of Washington Quality of Life (UW-QOL) questionnaire for head and neck cancer patients. In the 12 single question domains, the highest mean scores were found for “taste” (92.9), “shoulder” (90.9), “anxiety” (87.5), and “pain” (86.4), whereas the lowest scores were observed for “chewing” (57.1), “appearance” (67.9), and “saliva” (78.1). In the three global questions of the UW-QOL questionnaire, 80% of patients considered that their HRQoL was as good as or even better than it was compared to their HRQoL before cancer, and only 20% reported that their HRQoL had worsened after the presence of the disease. Overall QoL during the past 7 days was rated as good, very good or outstanding by 81% of patients, respectively. No patient reported poor or very poor QoL. In the present study, restoring mandibular continuity with free fibula flap and patient-specific titanium implants designed with the CAD-CAM technology improved HRQoL.

Aims: To compare marginal and internal fit of lithium disilicate (LDS), Biocompatible High-Performance Polymer (BIO-HPP), and monolithic zirconia ceramic endocrowns fabricated using computer-aided design and computer-aided manufacturing (CAD/CAM) technology. Materials and Methods: Thirty human extracted mandibular 1st molars were selected. Working length was established and biomechanical preparation was carried out to size 25%–4% using NeoEndo rotary files in the crown down technique. Intermittent irrigation was performed after each instrument by 5.25% sodium hypochlorite followed by irrigation with 17% Ethylenediaminetetraacetic acid to remove the smear layer. Final rinse was done with normal saline, and the canals were dried before obturation with a single cone gutta-percha technique and then randomly distributed into three-groups according to type of material used for fabrication. Group 1-LDS, Group 2-BIO-HPP, and Group 3-monolithic zirconia ceramic. Preparation of the samples was done for endocrowns, impression recorded with digital scanner followed by fabrication by CAD/CAM technique. Samples were sectioned in the midsagittal plane and evaluated under a stereomicroscope. Results: Bio-HPP biomaterial showed the highest marginal gap discrepancy followed by monolithic zirconia ceramic material and then LDS material in the descending order. Internal gap was highest in Monolithic Zirconia Ceramic material followed by Bio-HPP and LDS. LDS material exhibited minimal discrepancies in both the parameters (marginal and internal gap). Conclusion: Taking into account the limitations of this study, it is evident that the choice of Bio-HPP for endocrowns can be taken up in future after further clinical trials and long-term follow-up studies.

China-made 5-axis simultaneous contouring CNC machine tool and domestically developed industrial computer-aided manufacture (CAM) technology were used for full crown fabrication and measurement of crown accuracy, with an attempt to establish an open CAM system for dental processing and to promote the introduction of domestic dental computer-aided design (CAD)/CAM system. Commercially available scanning equipment was used to make a basic digital tooth model after preparation of crown, and CAD software that comes with the scanning device was employed to design the crown by using domestic industrial CAM software to process the crown data in order to generate a solid model for machining purpose, and then China-made 5-axis simultaneous contouring CNC machine tool was used to complete machining of the whole crown and the internal accuracy of the crown internal was measured by using 3D-MicroCT. The results showed that China-made 5-axis simultaneous contouring CNC machine tool in combination with domestic industrial CAM technology can be used for crown making and the crown was well positioned in die. The internal accuracy was successfully measured by using 3D-MicroCT. It is concluded that an open CAM system for dentistry on the basis of China-made 5-axis simultaneous contouring CNC machine tool and domestic industrial CAM software has been established, and development of the system will promote the introduction of domestically-produced dental CAD/CAM system.

Metal alloys have been used for many years as framework material of dental restorations. The conventional lost-wax and casting method, which was very popular in fabrication of metal frameworks, are now being replaced by computer-aided manufacturing technologies. Computer-aided manufacturing methods offer many advantages, such as standardization and quality in manufacturing, precise fit of restorations, and improved mechanical strength. Digital technologies used in fabrication of metal frameworks are simply classified as subtractive and additive computer-aided manufacturing systems, and each have their own subdivisions, which show differences in the used technology. This review summarizes computer-aided systems used in fabrication of metal frameworks in terms of use in dental practice, advantages, disadvantages and provides clinical recommendations.

The purpose of this study was to evaluate dental students' perceptions of traditional waxing vs. computer-aided crown design and to determine the effectiveness of either technique through comparative grading of the final products. On one of twoidentical tooth preparations, second-year students at one dental school fabricated a wax pattern for a full contour crown; on the second tooth preparation, the same students designed and fabricated an all-ceramic crown using computer-aided design (CAD) and computer-aided manufacturing (CAM) technology. Projects were graded for occlusion and anatomic form by three faculty members. On completion of the projects, 100 percent of the students (n=50) completed an eight-question, five-point Likert scalesurvey, designed to assess their perceptions of and learning associated with the two design techniques. The average grades for the crown design projects were 78.3 (CAD) and 79.1 (wax design). The mean numbers of occlusal contacts were 3.8 (CAD) and 2.9(wax design), which was significantly higher for CAD (p=0.02). The survey results indicated that students enjoyed designing afull contour crown using CAD as compared to using conventional wax techniques and spent less time designing the crown using CAD. From a learning perspective, students felt that they learned more about position and the size/strength of occlusal contacts using CAD. However, students recognized that CAD technology has limits in terms of representing anatomic contours and excursive occlusion compared to conventional wax techniques. The results suggest that crown design using CAD could be considered as an adjunct to conventional wax-added techniques in preclinical fixed prosthodontic curricula.

Objectives: This research was carried out to evaluate the effect of Polyetheretherketone (PEEK) as denture base material on peri-implant crestal bone level changes in edentulous patients rehabilitated with implant-supported primary-secondary bar overdenture and retained attachments attached the body of the bar constructed by CAD / CAM technology. Materials and Methods: Twenty completely edentulous patients complaining from insufficient retention of their mandibular denture were selected to participate in this study. All the patients were rehabilitated with an implant-supported bar overdenture. For All patients three implants (3.7mm) in diameter (11mm) in length were inserted in the interforamenal region using computer guided surgical template. Four months later, Cast bar with two semi precession attachment at the distal ends of the bar was constructed, The cast bar was scanned using bench laser scanner to obtain virtual model with the bar, the housing on the top of the bar and the female part of the attachment was designed using computer aided designing (CAD) the meld into wax by computer aided manufacturing (CAM). The CAD/ CAM wax pattern of housing and the female part of the attachments were transferred into acetal resin using the injection molded technique. Overdentures were constructed for all patients following the conventional technique. According to the denture base material, a toss coin was made to randomly divided the patients into two equal groups; group I received mandibular implant-retained overdenture were processed using heat cured acrylic resin, following the long curing cycle (heated at 78C° for eight hours), while for group II Polyetheretherketone (PEEK) lower overdenture was constructed, using the injection-molding technique. Radiographic evaluation of peri-implant bony changes was made using standardized long cone paralleling technique with custom made acrylic template and the Rinn-xcp at insertion, six, twelve and twenty four months were measured and statistically analyzed. The significant level was set at P ≤ 0.05P . ANOVA for repeated measures test was used to compare between follow up periods within groups and when statistically significant it was followed by simple main effect analysis with Bonferioni correction. One way ANOVA test was used to compare between groups at different follow up periods. Results. Both groups showed a statistically insignificant increase loss in crestal bone height around the implants. Although the data obtained from table1 revealed increase in the amount of bone changes for group I and Group II compared to group I during the follow up period statistical analysis of the data using ANOVA test for repeated measures revealed no significance difference(P ≥ 0.05) .Conclusion: CAD/ CAM technology and use of Polyetheretherketone (PEEK) as denture base material should be considered whenever possible to preserve the implant supporting structures in implant bar retained overdenture.

Background:Surgical cutting guides are used in mandibular reconstruction involving osteotomy of the mandible and fibula. Cutting guides produced using computer-aided design (CAD) and computer-aided manufacturing (CAM) technologies have been reported recently. These guides aim to increase the benefits to patients by improving the accuracy, shortening the operating time, and correcting occlusion. However, the availability of these advanced technologies is limited in some regions of the world. To test whether we could produce low-cost surgical cutting guides, we made surgical guides and investigated their accuracy.Methods:Using free CAD software, we designed surgical cutting guides for the mandible and fibula and used these to perform virtual mandibular segmental osteotomies and fibula transplants in 12 model surgeries. The cutting guides were printed on a 3-dimensional (3D) printer. The model surgeries were performed using 3D mandibular models and cutting guides to check their accuracy. Deviations between the virtually simulated plan and the actual model surgery were investigated.Results:CAD and CAM technologies were used to design and 3D print the cutting guides and models. The guided surgeries were performed. The deviations were about 1.3 mm for mandibular osteotomy, less than 1 mm for fibular osteotomy, and within 2.4 mm for reconstructions of the mandible.Conclusions:Without using expensive software or products, we were able to design surgical cutting guides for the mandible and fibula and used these to perform virtual simulation of mandibular segmental osteotomy and fibular reconstruction. Model surgeries using 3D-printed surgical guides showed that the accuracy of reconstruction was within a 3-mm deviation. In circumstances where commercial CAD/CAM guides are not available, it may be possible to use CAD/CAM surgical guides in the clinic if doctors are willing to volunteer their time for the design and printing.

The use of Computer Aided Design (CAD) / Computer Aided Manufacturing (CAM) to produce biomedical devices has recently become more interesting because of environmental benefits and the fact that it has been done using computer simulations. However, CAD / CAM operating costs are a major obstacle to product commercialization. High specification computers are used as a raw material for design, customizing the processes of transferring continuous digital images and small-size and high-quality manufacturing tools are major options to reduce the cost of CAD / CAM operations. The most widely used method is to optimize how CAD and CAM devices work through an algorithm. This optimization will contribute to the rapid development of the ability to produce better products and reduce operating costs. The case study to be conducted is the development of CAD / CAM optimization over the past years (2013, 2018) towards the production of biomedical devices.

With the rapid development of digital technology, its application in dental restoration becomes wider and the standard for the dental diagnosis and treatment becomes higher. Thanks to the progress of computer-aided design and manufacturing technology, a new digital era has come, where efficient, accurate and personalized treatment experience could be achieved in every treatment step of fixed prostheses, and the traditional mode with low efficiency and poor patient experience has been replaced. This article is to discuss the application status of digital technology in detail, including its advantages, limitations and future development. Key words: Prosthodontics; Dental, digital; Computer-aided design; Computer-aided manufacturing

The principles of nasal reconstruction include the need to reconstruct three tissue layers, the need to restore entire skin aesthetical units, and, possibly, the replacement with like tissues. Computer-aided design (CAD) and computer-aided manufacturing (CAM) technologies were applied to two total nasal reconstructions in male patients who underwent rhinectomy for cancer. Three-dimensional (3D) data were obtained from computerized tomography (CT) scan-derived DICOM files (Digital Imaging and Communications in Medicine), this allowed us to design the shape of the reconstructive nose in order to mimic the native nose and to plan dimensions and angles. A custom-made titanium plate was manufactured for the structure and a bi-dimensional template for the forehead flap was printed. The patients underwent a total nasal reconstruction in three layers: local flaps for the lining, custom-made titanium plate for the structure, and expanded forehead flap for the skin. Forehead flap pedicle was divided 3 weeks postoperatively under local anesthesia in an outpatient clinic, as well as further minor refinements. The patients underwent a 6-month post-operative CT scan in order to compare the result to the planned nose. No complications were reported. The superimposition demonstrated a 92% match in case 1 and 95% match in case 2 between the reconstructed nose and the planned one. Forehead flap is still the most favorable option for nasal reconstruction, CAD technology allows to implement the planning and makes the procedure easier; moreover, the use of a CAM plate for the structure allows to reconstruct a nose with the desired naso-frontal angle.Level of evidence: level V, therapeutic study.

Educational robotics has become a field of possibilities for teaching technologies, adding students new challenges that lead to professional practice. Therefore, the Açaímov Robotics Team from the Federal Institute of Education, Science and Technology of Maranhão - Campus Açailândia, Brazil, consisting of high school students integrated with the technical courses in electromechanics and industrial automation, included the technologies of Computer Aided Design (CAD), Computer Aided Manufacturing (CAM) and 3D Print in the development stages of robot structures. Through a group dynamic among the students to enhance results, the robot's structural specifications were determined based on the characteristics of the Journey to the Center if the Earth Challenge and the arrangement of controller board, sensors and actuators. This work demonstrates the efficiency of this methodology applied to the robotics group by presenting as a result the structure developed for the robot using Fusion 360 (CAD technology), Repetier Host (CAM technology) and 3D printing with biodegradable material.

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