scholarly journals An Experimental Strategy for Capturing the Margins of Prepared Single Teeth with an Intraoral Scanner: A Prospective Clinical Study on 30 Patients

Author(s):  
Francesco Guido Mangano ◽  
Bidzina Margiani ◽  
Ivan Solop ◽  
Nadezhda Latuta ◽  
Oleg Admakin

Purpose: To present an experimental strategy for successfully capturing the margins of prepared single teeth with an intraoral scanner (IOS). Methods: The protocol was as follows: (1) an intraoral impression was captured with an IOS, without taking care of the visibility of the margins; (2) a partial analog impression was taken by means of a 3D-printed custom tray filled with polyvinylsiloxane light, after the removal of a retraction cord; (3) the hollow portion of the analog impression, with the preparation margins clearly visible, was scanned extraorally with the same IOS; (4) the scan of the analog impression was imported into computer-assisted-design (CAD) software, where its normals were inverted; (5) the scan with inverted normals was registered on the first intraoral scan, and replaced it; (6) the technician designed the final restoration, which was fabricated and delivered for application. The study outcomes were: (1) the marginal adaptation of the final crown; (2) the quality of interproximal contacts; and (3) the quality of occlusal contacts. Results: Thirty patients (18 males, 12 females; mean age 51.3 ± 11.6 years) were selected for this study. All these patients were restored with a monolithic translucent zirconia crown, fabricated following the aforementioned protocol. The clinical precision and the marginal adaptation of the crowns were optimal, interproximal contact points were perfect, and the only necessary adaptations were occlusal, with some minor precontacts that had to be polished. Conclusions: The present protocol seems to be compatible with the fabrication of clinically precise zirconia crowns. Further studies are needed to confirm these results.

Author(s):  
Francesco Mangano ◽  
Bidzina Margiani ◽  
Oleg Admakin

Purpose: To present a novel, full-digital protocol for the design and fabrication of implant-supported monolithic translucent zirconia crowns cemented on customized hybrid abutments. Methods: The present retrospective clinical study was based on data from patients who had been treated with single Morse-taper connection implants (Exacone®, Leone Implants, Florence, Italy) and were prosthetically restored with monolithic translucent zirconia crowns, cemented on customized hybrid abutments. The full-digital protocol (SCAN-PLAN-MAKE-DONE®) consisted of 8 phases: (1) intraoral scan of the implant position with scanbody; (2) computer-assisted design (CAD) of the individual abutment (saved as “supplementary abutment design” in external folder) and temporary crown; (3) milling of the individual zirconia abutment and of the temporary polymethyl-methacrylate (PMMA) crown, with extraoral cementation of the zirconia abutment on the relative titanium bonding base, to generate an individual hybrid abutment; (4) clinical application of the individual hybrid abutment and cementation of the temporary PMMA crown; (5) two months later, intraoral scan of the individual hybrid abutment in position; (6) CAD of the final crown with margin line design on the previously saved “supplementary abutment design”, superimposed on the second scan of the abutment in position; (7) milling of the final crown in monolithic translucent zirconia, sintering, and characterization; and (8) clinical application of the final crown. All patients were followed for a period of 1 year. The primary outcomes of this study were the marginal adaptation of the final crown (checked clinically and radiographically), the quality of occlusal and interproximal contact points at delivery, and the aesthetic integration; the secondary outcomes were the 1-year survival and success of the implant-supported restoration. An implant-supported restoration was considered successful in the absence of any biological or prosthetic complication, during the entire follow-up period. Results: In total, 25 patients (12 males, 13 females; 26–74 years of age; mean age 51.1 ± 13.3 years) who had been restored with 40 implant-supported monolithic translucent zirconia crowns were included in this study. At delivery, the marginal adaptation was perfect for all crowns. However, there were occlusal issues (2/40 crowns: 5%), interproximal issues (1/40 crowns: 2.5%), and aesthetic issues (1/40 crowns: 2.5%). The overall incidence of issues at delivery was therefore 10% (4/40 crowns). At 1 year, one implant failed; thus the survival of the restorations was 97.5% (39/40 crowns in function). Among the surviving implant-supported restorations, three experienced complications (one loss of connection between the hybrid abutment and the implant, one decementation of the zirconia abutment, and one decementation of the zirconia crown). The success of restorations amounted to 92.4%. Conclusions: The restoration of single Morse-taper connection implants with monolithic translucent zirconia crowns cemented on customized hybrid abutments via the novel SCAN-PLAN-MAKE-DONE® full-digital protocol seems to represent a reliable treatment option. However, further studies on a larger number of patients and dealing with different prosthetic restorations (such as implant-supported fixed partial prostheses) are needed to confirm the validity of this protocol.


Tribologia ◽  
2020 ◽  
Vol 292 (4) ◽  
pp. 79-87
Author(s):  
Jan Zwolak ◽  
Marek Martyna

The work analysed contact stresses and slippage occurring in specific toothed pairs of two power shift gearings with eight ratios. The analysed gearings have ratios of identical values. Differences in contact stresses and slippage values within individual toothed pairs of both gearings (at same values of input torque and engine speed) result from the internal configuration of the kinematic chains created by the toothed gears within individual gear ratios. The analysis included 5 characteristic contact points within the tooth engagement area. They were selected analytically depending on geometrical parameters of gears that constitute the toothed pair. Using computer-assisted design works that employ multi-criterion optimisation, it is possible to minimize slippage and take reasonable advantage of the fatigue contact durability of the material that was used for producing the toothed gears.


2015 ◽  
Vol 38 (5) ◽  
pp. E5 ◽  
Author(s):  
Jehuda Soleman ◽  
Florian Thieringer ◽  
Joerg Beinemann ◽  
Christoph Kunz ◽  
Raphael Guzman

OBJECT The authors describe a novel technique using computer-assisted design (CAD) and computed-assisted manufacturing (CAM) for the fabrication of individualized 3D printed surgical templates for frontoorbital advancement surgery. METHODS Two patients underwent frontoorbital advancement surgery for unilateral coronal synostosis. Virtual surgical planning (SurgiCase-CMF, version 5.0, Materialise) was done by virtual mirroring techniques and superposition of an age-matched normative 3D pediatric skull model. Based on these measurements, surgical templates were fabricated using a 3D printer. Bifrontal craniotomy and the osteotomies for the orbital bandeau were performed based on the sterilized 3D templates. The remodeling was then done placing the bone plates within the negative 3D templates and fixing them using absorbable poly-dl-lactic acid plates and screws. RESULTS Both patients exhibited a satisfying head shape postoperatively and at follow-up. No surgery-related complications occurred. The cutting and positioning of the 3D surgical templates proved to be very accurate and easy to use as well as reproducible and efficient. CONCLUSIONS Computer-assisted virtual planning and 3D template fabrication for frontoorbital advancement surgery leads to reconstructions based on standardizedmeasurements, precludes subjective remodeling, and seems to be overall safe and feasible. A larger series of patients with long-term follow-up is needed for further evaluation of this novel technique.


2020 ◽  
Vol 9 (12) ◽  
pp. 4008
Author(s):  
Simon Raveau ◽  
Fabienne Jordana

The three-dimensional printing of scaffolds is an interesting alternative to the traditional techniques of periodontal regeneration. This technique uses computer assisted design and manufacturing after CT scan. After 3D modelling, individualized scaffolds are printed by extrusion, selective laser sintering, stereolithography, or powder bed inkjet printing. These scaffolds can be made of one or several materials such as natural polymers, synthetic polymers, or bioceramics. They can be monophasic or multiphasic and tend to recreate the architectural structure of the periodontal tissue. In order to enhance the bioactivity and have a higher regeneration, the scaffolds can be embedded with stem cells and/or growth factors. This new technique could enhance a complete periodontal regeneration. This review summarizes the application of 3D printed scaffolds in periodontal regeneration. The process, the materials and designs, the key advantages and prospects of 3D bioprinting are highlighted, providing new ideas for tissue regeneration.


2017 ◽  
Vol 19 (4) ◽  
pp. 490-494 ◽  
Author(s):  
Melissa LoPresti ◽  
Bradley Daniels ◽  
Edward P. Buchanan ◽  
Laura Monson ◽  
Sandi Lam

Repeat surgery for restenosis after initial nonsyndromic craniosynostosis intervention is sometimes needed. Calvarial vault reconstruction through a healed surgical bed adds a level of intraoperative complexity and may benefit from preoperative and intraoperative definitions of biometric and aesthetic norms. Computer-assisted design and manufacturing using 3D imaging allows the precise formulation of operative plans in anticipation of surgical intervention. 3D printing turns virtual plans into anatomical replicas, templates, or customized implants by using a variety of materials. The authors present a technical note illustrating the use of this technology: a repeat calvarial vault reconstruction that was planned and executed using computer-assisted design and 3D printed intraoperative guides.


Author(s):  
Kamilla Carneiro Agreli ◽  
Idiberto José Zotarelli Filho ◽  
Elias Naim Kassis

Introduction: Dental implant procedures have increased worldwide, reaching approximately one million dental implants per year. The optimization of faster and more accurate techniques by dentists and postoperative surgeons with better results and quality of life stimulated the development of numerous software and hardware for performing computer-guided surgeries, so-called virtual surgeries (VS). Objective: to present, through a systematic review, the main considerations of virtual surgery in dentistry and their respective advantages, disadvantages, and limitations. Methods: The model used for the review was PRISMA. We used databases such as Scielo, Lilacs, Google Scholar, PubMed. Major findings: In the scenario of VS in dentistry, advances in technology have contributed to the improvement of the models, since there was only the direct molding technique to obtain patient models, with the positioning of implants not very favorable in terms aesthetics. The information that is acquired in the 3D reconstructions allows us to determine the quantity and quality of the available bone and also allows the simulation of the installation of the implants in a virtual environment. This provides predictability of techniques and difficulties that can be encountered during surgical intervention, reducing the time and the possibility of errors, allowing the overall reduction of oral rehabilitation costs. Conclusion: Preoperative virtual planning and reconstruction of the mandible guided by dental implants through preoperative designs provide high success rates for the implant and dental rehabilitation, benefiting also prosthetic restorations supported by fixed implants. Still, the concept of using personalized implants with the help of 3D virtual treatment planning, stereolithographic models, and computer-assisted design greatly improves the mandibular restoration and helps to obtain a good facial profile, aesthetic and dental rehabilitation, avoiding complications with the grafts autologous.


2008 ◽  
Vol 55 (4) ◽  
pp. 259-267
Author(s):  
Igor Drstvensek ◽  
Natasa Ihan-Hren ◽  
Tadej Strojnik ◽  
Vojko Pogacar ◽  
Hartner Zupancic ◽  
...  

The use of contemporary technologies of Computer Assisted Design (CAD), combined with latest rapid prototyping, tooling and manufacturing, with traditional CT scanning techniques and high medical skills are used as instruments for better diagnostic visualization, simulation of procedures and treatment of patients with craniofacial deformities. They also improve the overall performances of medical and nursing staff thus influencing the quality of medical service. Patients with congenital defects, orthognathic deformities, deformities after malignancy treatment or after craniofacial traumatic injuries of different severities are of particular interests due to both aesthetic and functional alterations. The paper presents two clinical cases - a patient with scull bone defect after brain hemorrhage and brain edema as well as a patient with hemifacial microsomia treated by surgery followed by implantation of titanium angular implant prepared by means of computer tomography scans, Computer Aided Design and Rapid Manufacturing technologies.


2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Liyun Bai ◽  
Ping Ji ◽  
Xian Li ◽  
Hui Gao ◽  
Linlin Li ◽  
...  

Individualized titanium mesh holds many advantages over conventional mesh. There are few reports in the literature about the effect of mesh pore size and mesh thickness on the mechanical properties of titanium mesh. This study is designed to develop an individualized titanium mesh using computer-assisted design and additive manufacturing technology. This study will also explore the effect of different thicknesses and pore sizes of titanium mesh on its mechanical properties through 3D FEA. According to this study, the mechanical properties of titanium mesh increased when the thickness decreased (0.5 mm to 0.3 mm). With an increase in mesh diameter (3 mm to 5 mm), the mechanical properties of mesh decreased. The diameter of titanium mesh has less influence on its mechanical properties than does the thickness of the mesh. Titanium mesh with a thickness of 0.4 mm is strong enough and causes less stimulation to mucosa; therefore, it is more suitable for clinical use. In addition, parameters of titanium mesh should be decided clinically according to bone defect size, defect location, and force situation.


2017 ◽  
Vol 24 (1) ◽  
pp. 87-106
Author(s):  
Wiharyanto Wiharyanto

The study aims to analyze about the low graduation and certification exam training participants of the procurement of goods / services of the government and its contributing factors, and formulate a strategy of education and training and skills certification exams procurement of goods / services of the government. Collecting data using the method of study documentation, interviews, and questionnaires. Is the official source of information on the structural and functional Regional Employment Board, as well as the participants of the training and skills certification exams procurement of goods / services of the government in Magelang regency government environment. Analysis using 4 quadrant SWOT analysis, to determine the issue or strategic factors in improving the quality of education and training and skills certification exams procurement of government goods / services within the Government of Magelang regency. The results show organizer position is in quadrant I, which is supporting the growth strategy, with 3 alternative formulation strategies that improve the quality of education and training and skills certification exams procurement of government goods / services, and conducts certification examination of the procurement of government goods / services with computer assisted test system (CAT). Based on the research recommendations formulated advice to the organizing committee, namely: of prospective participants of the training and skills certification exams procurement of goods / services the government should consider the motivation of civil servants, is examinees who have attended training in the same period of the year, the need for simulation procurement of goods / services significantly, an additional allocation of training time, giving sanction to civil servants who have not passed the exam, the provision of adequate classroom space with the number of participants of each class are proportional, as well as explore the evaluation of education and training and skills certification exams procurement of goods / services for Government of participants.


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