The application of simulators in dental medicine students’ training

The simulation training of dental students has developed rapidly in recent years. The development of new technologies and virtual reality are an indispensable part of the education of dental students. The introduction of simulators in the education of dental students supports the harmonization and integration of knowledge from the pre-clinical and clinical education of the students. The opportunity to train on simulators in the field of dentistry helps future dentists to put their theoretical knowledge into practice and gain confidence to work with patients. Simulation operators are included in the students’ pre-clinical exercises. In recent years, computer-based simulation and virtual reality-based simulation have become an indispensable part of the pre-clinical training of dental students. Nowadays, there is a wide range of dental simulator models with different features and functions. Some of them are: DentSim, Haptic Technology, Moog Simodont Dental Trainer, HapTEL, the Geneva System, Robotic Patients for Virtual Dental Patient Simulation, Virtual Reality Dental Training System, PerioSim, the VirDenT system, the Forsslund System, DSETM Expert Dental Simulation Units—KaVo Dental. In addition to student training, these simulators can also be used to assess learner performance or quality control various teaching methods. The development of new technologies marks successes in the development and improvement of the simulators applied in the training of dental medicine students. The virtual patient application provides many opportunities to recreate clinical situations in virtual reality and will make learning even more rewarding and interesting for dental students

Students’ opinion survey on online dental education

The purpose of the present study is to examine the students’ opinion regarding the conducted online education. Sociological methods: an anonymous Google forms survey was conducted including dental medicine students studying in the conditions of the COVID-19 pandemic, which led to the need to switch to an online form of education. It was conducted online on a voluntary basis in the month of March 2021. A total of 50 students from various years, studying Dental Medicine at the Medical University of Varna took part in the study. The provided survey consists of 20 questions. The majority of students categorically state that face-to-face study is preferable and that digital learning methods are motivating for them. Almost half of the students have a positive opinion regarding online lectures. Through them, they get more advice and guidance from the teachers and it is easier to participate in discussions. The participants in the survey shared that online training, as a result of the introduced anti-epidemic measures, was a good option for learning the theoretical study material

Simulations of cast and selective laser melted dental bridges with chewing load

The aim of the present paper is to evaluate and compare the strength properties and deformation characteristics of cast and Selective Laser Melted (SLM) Co-Cr dental alloys by using CAD/CAE software. The Solid Works Simulation software is used for simulation of chewing loading of the virtual 3D model of four-part dental bridge. Two Co-Cr dental alloys, cast and SLM were used in this study. During simulation process by means of linear static analysis the displacements, strains, stresses, and reaction forces under the effect of the applied load were calculated. As a result, the equivalent von Mises stresses, Factor Of Safety (FOS) and displacements were evaluated in this study.It was established that the highest values of the equivalent von Mises stresses of cast and SLM bridges are situated in the connectors between the teeth, i.e. the zones with the lowest areas of the cross sections. They are in the range 95-162 MPa, which is lower than the stress limits for the both materials. The minimum FOS of the both materials is higher than 1. In the cast bridges it is 1.32-2.64 in the zones with the highest loading, while in the SLM samples it is 2.61-5.68. As FOS shows the reserve strength of the material for the applied load, it is obvious that the SLM bridge possesses twice higher reserve strength. This allows optimization of the construction, economy of material and possibility for manufacturing of objects with porous structures

Possibilities of 3D printer Rapidshape D30 for manufacturing of cubic samples

The purpose of the present paper is to establish experimentally the possibilities of the 3D printer Rapidshape D30 for the manufacturing of standard cubic samples from different types of monomers and to evaluate their geometrical accuracy and roughness.Standard cubic samples with dimensions 5mm х 5mm х 5mm were printed from all the materials, given by the producer, in two ways of dimensional orientation according to the base – horizontally and inclined at 45о. They were manufactured with 3D printer Rapidshape D30, working on a stereolithography principle with LED light.It was established that:❖❖ The samples, made of NextDent Surgical Guide, have the highest dimensional accuracy and the lowest deviation interval in both ways of placement. This polymer is characterized with the highest thickness of the polymerization layer – 0.100 mm, but it is transparent, thus ensuring the entire polymerization throughout the depth of the whole layer. NextDent C+B, intended for manufacturing of temporary crowns and bridges, occupies a middle position in comparison to the other 6 materials.❖❖ Nearly in all the materials the surface roughness of the cube with horizontal placement is lower than that of the cube printed inclined (average values of Ra 0.46-2.69μm and Ra 1.74-2.77, respectively).❖❖ In 3D printing the surface roughness depends on the thickness of the polymerization layer and the inclination to the printing direction. The thicker the polymerization layer and the larger the slope, the higher the surface roughness

Investigation of the dental technicians’ readiness to manufacture dental prostheses using digital technologies

Introduction: Modern digital technologies allow us to generate a virtual model of the patient and to design his/her smile.  The future definitely belongs to the digital technologies because they offer a reliable, predictable and highly esthetic manner of treatment.Aim: The aim of the present study is to investigate the dental technicians' readiness to manufacture dental prostheses using digital technologies.Materials and Methods: A total of 159 respondents - practicing dental technicians and   students - were surveyed using an online survey. The survey was conducted via a social network platform.Results were processed with SPSS v. 20 using variational, comparative and correlation analyses. Results: Over 50% of the respondents have indicated that they use different types of digital technologies in their practice, the main reason being that the construction time is shortened and that the accuracy is improved (85.20%). There is a correlation between the length work experience and the use of new technologies (p<0.05), with younger specialists being the ones who primarily use modern technology. Young specialists are willing to invest in the purchase of modern equipment and to attend additional courses on working with it.Conclusion: Despite the variety of methods for recreating the prosthetic field when manufacturing prosthetic constructions, a trend towards full digitalization of the process is observed.The results from the conducted analyses show that digitalization is being increasingly used by young specialists (CAD planning and software application – 78.40%), who prefer it because it increases accuracy and shortens production time (85.40%)

3D-printing in contemporary prosthodontic treatment

The purpose of the present paper is to make a review of the applications for 3D-printing in contemporary prosthetic treatment as this modern technology has become widely spread not only in the industry but in medicine and dentistry, too. It is a form of additive manufacturing technology where a three-dimensional object is created by laying down successive layers of material

Is it possible to use 5 G in dental medicine education?

Information and communication technologies have reached their peak in recent years. With the development of virtual reality technologies, sensors and robotics, dental simulators provide better working conditions and facilitate the transition from the traditional simulation laboratory to the clinic. Innovations in digital technology, telemedicine, 5G technology and artificial intelligence (AI) create new opportunities for teaching dental students. Dentistry is a very precise specialty and the development of technology allows progress in the clinical training of dental students. The aim of the present study is to investigate the possibility of applying 5G technologies in the education of dental students. Using new technologies, dental simulators can now create an environment in which medical university students can practice clinical procedures such as prosthetic dentistry, endodontics, prosthetic dentistry, implantology  and even extractions

Fixed Partial Dentures of Co-Cr Alloys Using Additive Manufacturing //// Неснемаеми протезни конструкции от Co-Cr сплави, изработени чрез технологии с добавяне на материал

[EN] Depending on the clinical situation and patient's condition, the restoration of missing teeth is carried out in various ways. Treatment with Fixed Partial Dentures (FPD) ensures very good aesthetics, physiological transmitting of the chewing load, even distribution of the masticatory loads and greater durability compared with the removable partial dentures. Conventional technology for production of FPD by casting with hand-built wax pattern is characterized with low accuracy, long-lasting manufacturing process and a high price. During the past 20 years innovative technologies enter very rapidly in the dental laboratories. The implementation of CAD-CAM systems lead to the elimination of many manual operations, increase the accuracy of the dental construction and decrease the time for their production. In the recent years, there is greater emphasis on the development of technologies for production by adding of material, so called Additive Technologies (AT) or Additive Manufacturing (AM). They give opportunity to produce complex personalized details of a wide range of materials - polymers, composites, ceramics, metals and alloys. They allow manufacturing of dense parts and parts with a predetermined porosity and surface roughness as well. The processes used are fast, reliable and easy for managing and control. The new equipment and the new technologies rapidly evolve and enter almost immediately after their development in dental laboratories and dental surgeries. The experience to work with them and the data associated with their application are insufficient. Therefore, the aim of the present work is to investigate the geometric accuracy and mechanical properties of fixed partial dentures of Co-Cr alloys produced by additive technologies, and to propose clinical and laboratory protocols for their application in dentistry.[BG] В дисертационния труд е направен сравнителен анализ на свойствата на неснемаеми дентални конструкции, произведени по: 1) класическа технология – леене по восъчни модели; 2) леене по модели, изработени чрез 3D печат и 3) избирателно лазерно стопяване. Разработена е методика за изследване точност при ажустиране на неснемаеми протезни конструкции с CAD софтуер. Установено е, че мостовите конструкции, отлети с 3D принтирани модели, са с най-висока точност, но са с по-голяма грапавост в сравнение с конструкциите, изработени по класическата технология (Ra=3.39 µm и Ra=1.11-1.31 µm съответно). Доказано е, че якостта на адхезия на керамично покритие към сплав Co212-f, изработена чрез ИЛС, е с 23% по-голяма от тази на керамика към отлята сплав Biosil F (83,1 МРа и 67,5 МРа съответно). Дефинирани са термините “частично дигитализиран план на лечение“ и „изцяло дигитализиран план на лечение“. Потвърдено е, че грапавостта на мостовите конструкции, изработени чрез ИЛС, е най-висока (Ra=4.24 µm) в сравнение с грапавостта на неснемаеми протези, изработени чрез леене с ръчно изработени или 3D принтирани модели. Потвърдено е, че твърдостта и границата на провлачване на образци от Co-Cr сплави, изработени чрез ИЛС (382 HV0,1 и 39 HRC, R0.2= 720 MPa), са по-високи от тези на образци, изработени чрез центробежно леене (335 HV0,1 и 33 HRC; R0.2= 410 MPa). Разработени са клинични протоколи за приложение на технологиите с добавяне на материал за производство на неснемаеми протезни конструкции

APPLICATION OF SELECTIVE LASER MELTING IN MANUFACTURING OF FIXED DENTAL PROSTHESES

The additive technologies characterize with the building of one layer at a time from a powder or liquid that is bonded by means of melting, fusing or polymerization. They offer a number of advantages over traditional methods: production of complex personalized objects without the need of complex machinery; manufacturing of parts with dense as well as the porous structure and predetermined surface roughness; controllable, easy and relatively quick process. The methods, mostly used in prosthetic dentistry, include stereolithography, selective laser sintering, and selective laser melting. The aim of the present paper is to review the features of the Selective Laser Melting (SLM) process and the possibilities of its application for production of fixed dental prostheses. The features of the SLM process, the microstructure and mechanical characteristics of dental alloys as well as the properties of fixed dental prostheses, fabricated via SLM, were discussed. It was revealed that the SLM Co-Cr dental alloys possess higher mechanical and tribo-corrosion properties, comparatively good fitting ability and higher adhesion strength of the porcelain comparing to the cast alloys. All this is a good precondition for successful application of the SLM process in the production of fixed dental prostheses, mainly of frameworks for metal-ceramic and constructions covered with polymer/composite, intended for areas with high loading