Wyniki wyszukiwania - BazTech

1

Corrosion Assessment of Nickel - Base - Dental Alloys in Ringer Biological Solution Studied by Electrochemical Techniques

Benea Lidia, Dragus L., Mocanu D.

Archives of Metallurgy and Materials

|

2022

|

Vol. 67, iss. 2

529--533

EN

The aim of this paper was to study the corrosion behavior of Nickel - Base - Dental Alloys in Ringer biological fluid. The Nickel base alloys are widely used for medical purposes, especially for prosthetic works in the field of dentistry. The applied electrochemical methods used for corrosion investigations are Open Circuit Potential, Linear Polarization during time of immersion in order to calculate the polarization resistance and corrosion rate. Potentiodynamic Polarization diagrams was performed to appreciate the passive domain. Ni-Cr Ugirex alloy show a better corrosion resistance in Ringer solution which will be reflected in a longer life of the dental structures made with this alloy as compared to the Ni-Cr Ducinox alloy, which will result in dental structures with a shorter lifespan. The electrochemical studies has shown that the alloy have a corrosion behavior similar to a passivating alloy, displaying an extensive passivity area due to formation of an oxide film.

2

Study the precision of fixed partial dentures of Co-Cr alloys cast over 3D printed prototypes

Dikova T., Dzhendov D., Katreva I., Tonchev T.

Archives of Materials Science and Engineering

|

2018

|

Vol. 90, nr 1

25--32

EN

Purpose: of this paper is to investigate the accuracy of Co-Cr dental bridges, manufactured using 3D printed cast patterns. Design/methodology/approach: Four-unit dental bridges are fabricated from the alloys i-Alloy and Biosil-f by lost-wax process. The polymeric cast patterns are 3D printed with different layer’s thickness (13 pm, 35 pm and 50 pm). Two 3D printers are used: stereolithographic “Rapidshape D30” and ink-jet “Solidscape 66+”. The geometrical and fitting accuracy as well as the surface roughness are investigated. Findings: It is established that Co-Cr bridges, casted from 3D printed patterns with 50 pm layer thickness, characterize with the largest dimensions - 3.30%-9.14% larger than those of the base model. Decreasing the layer thickness leads to dimensional reduction. The dimensions of the bridges, casted on patterns with 13 pm layer thickness, are 0.17%-2.86% smaller compared to the primary model. The average roughness deviation Ra of the surface of Co-Cr bridges, manufactured using 3D printed patterns, is 3-4 times higher in comparison to the bridge-base model. The greater the layer thickness of the patterns, the higher Ra of the bridges. The silicone replica test shows 0.1-0.2 mm irregular gap between the bridge retainers and abutments of the cast patterns and Co-Cr bridges. Research limitations/implications: Highly precise prosthetic constructions, casted from 3D printed patterns, can be produced only if the specific features of the 3D printed objects are taken in consideration. Practical implications: Present research has shown that the lower the thickness of the printed layer of cast patterns, the higher the dimensional accuracy and the lower the surface roughness. Originality/value: The findings in this study will help specialist in dental clinics and laboratories to choose the right equipment and optimal technological regimes for production of cast patterns with high accuracy and low surface roughness for casting of precise dental constructions.

3

Fatigue testing of dental bridges on selected examples

Urban D., Jałbrzykowski M., Gołębiewska M.

Acta Mechanica et Automatica

|

2017

|

Vol. 11, no. 1

53--57

EN

The paper presents example tests of the functional quality of selected designs of dental bridges. These were: porcelain bridges on a metal base (cobalt based alloy), porcelain bridges on a zirconia base (zirconia ceramic – Zirkon Zahn), and full zirconia bridges (Zirkon Zahn). For the purpose of the study, durability of bridges in cyclic fatigue testing was adopted as a measure of their quality. The tests were carried out on a Zwick Roell Z010 universal testing machine. They consisted in cyclic loading and unloading of dental bridges mounted on gypsum models at a loading force of F= 400 [N] and a frequency of load of f= 1 [Hz]. Each bridge was subjected to a cycle of 7200 loads. The results show that there are no significant differences in the functional quality of the bridges.

4

Accuracy of polymeric dental bridges manufactured by stereolythography

Dikova T, Dzhendov D., Katreva I., Pavlova D.

Archives of Materials Science and Engineering

|

2016

|

Vol. 78, nr 1

29--36

EN

Purpose: Purpose of this paper is to investigate the accuracy of dental bridges produced via digital light projection stereolithography process. Design/methodology/approach: 3D printer Rapidshape D30 was used for manufacturing of two groups of samples – temporary four-part bridges and cast patterns for permanent bridges. The temporary bridges were made of NextDent C+B polymer, while the cast patterns - of NextDent Cast. The samples were manufactured with different layer’s thickness (0.035 mm and 0.050 mm). The geometrical and adjusting accuracy were investigated by measuring of the samples’ dimensions and silicone probe, while the surface roughness was studied out by profile meter and optical microscopy. Findings: It was established that the dimensions of the temporary bridges and the cast patterns, printed with layer thickness 50 µm, are larger than that of the virtual 3D model with 0.1-0.3 mm. Decreasing the layer thickness to 35 µm leads to 0.29%-1.10% smaller sizes of dental bridges and cast patterns in comparison to that of the virtual 3D model. The average roughness deviation Ra of the 3D printed temporary bridges and cast patterns is larger than that of the initial model. As the surface roughness depends on the layer’s thickness, the samples with 0.035 mm layer characterize with lower Ra values. The silicone probe shows that the temporary bridges as well as the cast patterns need additional adjusting in the dental office or corrections during design of the virtual 3D model and 3D printing process in the dental laboratory. Practical implications: The stereolithography as part of CAD/CAM manufacturing process characterizes with high accuracy as a whole. But present study reveals that additional adjusting or preliminary corrections of the design of 3D printing process are needed for dental constructions produced by SLA. Originality/value: The geometrical and fitting accuracy as well as the surface roughness of dental bridges, produced by stereolithography were evaluated. The data, shown in the present study, will help dentists and dental technicians to precise the manufacturing regimes for production of dental constructions with high accuracy.

5

Designing and manufacturing of implantoprosthetic fixed suprastructures in edentulous patients on the basis of digital impressions

Malara P., Dobrzański L. B.

Archives of Materials Science and Engineering

|

2015

|

Vol. 76, nr 2

163--171

EN

Purpose: The aim of the paper is to present the method of computer aided planning and manufacturing of a prosthetic suprastructure based on 6 implants in the totally edentulous mandible using digital intraoral scans. Design/methodology/approach: TThe method of computer aided planning and manufacturing of the implantoprosthetic restoration in the completely edentulous mandible using digital scans is presented on the example of a real clinical case of a patient with a significant deficit of alveolar bone qualified for the implant treatment. The abutments and the final fixed metal-ceramic bridge was designed and manufactured only on the basis of digital scanning of the intraoral supporting area instead of using traditional impression materials and trays. Findings: The method of computer-aided design and manufacturing of fixed restorations in the mandible using a digital scan of the supporting area is a powerful technique for improving the treatment process, through which the clinician and the patient may obtain satisfactory results in terms of functionality and aesthetics. Practical implications: The experience gained by the authors of the article in the technique of computer aided designing and manufacturing of fixed bridges on the basis of digital intraoral scans allows for the formulation of rules that must be followed at both clinical and laboratory stages. The properly performed scanning allows to obtain greater precision of the final restoration in terms of fit and occlusal accuracy. Originality/value: This paper presents an original methodology of obtaining information about intraoral configuration of the soft tissues and the position of the implants with the use of digital scanning. This method allows for designing and manufacturing of both the abutments and the final restoration without using impression materials which is especially useful in patients with significant bone loss and the gag reflex.

6

Strength analysis of a three-unit dental bridge framework with the Finite Element Method

Reimann Ł., Żmudzki J., Dobrzański L.

Acta of Bioengineering and Biomechanics

|

2015

|

Vol. 17, no. 1

51--59

EN

Purpose: The aim of the study was to analyse the strength of a prosthetic bridge with variable geometry in the connectors between the span and the retention elements on the pillar teeth crowns. Methods: Research was carried using the Finite Elements Method (FEM) on a model of the bridge in the anterior teeth arch in the field 21–22–23, obtained using a contact scanner and computer aided design (CAD) system, with four different cross-sectional areas of the connectors: 4.0, 5.0, 5.5, and 6.0 mm2. For that purpose, the impact of the properties of selected metal alloys on the deflection of the prosthesis was analysed. Results: On the basis of the analyses, it was found that when the loading force acted obliquely, the stress was 19% higher compared to the stress with a loading vertical force. In the case of connectors with the smallest cross-sectional area, the stress exceeded permissible value (with safety factor n = 2) for one of the alloys. Conclusions: Deflection of the bridges tested changed depending on the connector cross-section and the elastic modulus of the selected material.

7

Protetyczne podbudowy ze stałą warstwą ceramiczną

Czakon K., Wita K., Hajduga M.

Aktualne Problemy Biomechaniki

|

2014

|

z. 8

17--20

PL

We współczesnej protetyce stomatologicznej ważny jest odpowiedni dobór i połączenie materiałów. W pracy skupiono się na sprawdzeniu połączenia porcelany z trzema różnymi rodzajami podbudów (metal frezowany, spiek i cyrkon). Trwałość połączenia materiałów w stomatologii to znaczący aspekt decydujący o jakości wykonanej pracy protetycznej. Wnioski formułowano na podstawie wyników z wykonanych zdjęć makroskopowych i przeprowadzonego badania twardości. Stwierdzono że warstwa nałożona na podbudowę cyrkonową cechuje się najlepszym ciągłym połączeniem.

EN

In todays dental prosthodonties a suitable selection and connecting the materials is important while using permanent prothesis there are a lot of problems with different periodontal conditions of each patient. Biomechanical factors are important and cementing materials used to their accomplishment. The range of this study has been devoted to show the continuity of adhesing the porcelain to the top layer.

8

Digitization procedure of creating 3D model of dental bridgework reconstruction

Dobrzański L. A., Reimann Ł.

Journal of Achievements in Materials and Manufacturing Engineering

|

2012

|

Vol. 55, nr 2

469--476

EN

Purpose: The still growing patient requirements is concerned with aesthetics but also with strength of the prosthetic restorations. Resistance on stresses depends among others on the shape, so it is necessary to transfer the dentures of a physical model to a computer environment and a simulation of the work conditions. The aim of that work was to study the methodology of digitization of a plaster model into a numerical model, using CAD/CAM dental system and CAD application, which can be in a next step imported to ANSYS application in order to realize stress analysis. Design/methodology/approach: To realize the transfer of a physical model of the dental bridge to a computer environment the 3i Incise Renishaw scanner which saved the plaster model by a probe about 1 or 3 mm diameter, moved in the scanner arm and contacted with it was used. A scanned plaster mode was exported into STL file and then opened in DentCAD Delcam application. Using the CAD module the preparation line was marked, a pontic was orientated in a right position and connectors of the pillar teeth and the pontic. Geometry and the cross section of the connectors depend on the bridgework strength. A designed bridge reconstruction was imported to CAD application and there curves were firstly drawn, then changed into NURBS surfaces and finally surfaces were merged into one solid model. A ready model can be imported up to ANSYS software in order to realize the stress analysis. Findings: A prepared dental case from a physical one was changed into a numerical model in following steps: scanning a plaster model by a contact scanner, designing the bridgeworks in CAD dental software environment, importing in CAD application, building the solid model and at the end importing in ANSYS software. Selected digitization procedure let to make all engineering calculations and analysis without manufacturing the physical model, what considerably reduce cost of the research investigations. Practical implications: A realized work gave an information about possibilities of verification for a physical model of restoration and a numerical model which can be compared to results from software simulation of behaviour of the bridgework in different load cases. Originality/value: The paper presents that it is not necessary to have a physical reconstruction model, to check the resistance on stress because it is possible to use the CAD/CAM dental system to design the dentures and then modelling the boundary conditions and observe the stress analysis.

9

Wpływ środowiska jamy ustnej na uzupełnienie protetyczne metalowo – ceramiczne

Hajduga M., Zdziech T.

Aktualne Problemy Biomechaniki

|

2011

|

z. 5

45--52

PL

Celem pracy jest zbadanie wpływu długotrwałego oddziaływania środowiska jamy ustnej na charakter połączenia struktury mostu metalowoceramicznego. W pracy przedstawiono charakter połączenia materiałów jak i wyniki składu chemicznego pierwiastków na granicy ich połączenia. Zakres pracy obejmuje badania strukturalne, metalograficzne oraz mikroanalizę rentgenowską (JCXA 733 firmy Jeol).

EN

The aim of the work is to analyze the effect of the long-lasting influence of the oral cavity environment on the character of the structural connection of the metallic-ceramic bridge. The character of the connection between the materials as well as the records of the chemical structure of the elements on the border line have been presented. The research includes the metallographic structural analysis performed by means of the electron microprobe analyzer (JCXA 733 Jeol).

10

Wytrzymałość mostów protetycznych

Gralewski J., Bogusławski G.

Aktualne Problemy Biomechaniki

|

2007

|

z. 1

203--209

PL

W pracy przeprowadzono analizę stanu naprężenia i odkształcenia mostów protetycznych oraz reakcji podporowych dla różnych przypadków obciążeń. Uzyskane wyniki obliczeń pozwolą określić ugięcie i wytężenie materiału mostów protetycznych, a obliczone wartości reakcji podporowych pozwolą określić obciążenia zębów filarowych. Analizę prowadzono za pomocą metody elementów skończonych przy pomocy programu ANSYS, wykorzystując specjalnie przygotowany plik wsadowy ułatwiający analizę parametryczną dla różnych przypadków obciążeń i wymiarów geometrycznych mostów (przekrojów poprzecznych i długości przęseł mostów protetycznych).

EN

This paper describes numerical analysis of stress and strains in dentures bridges for various supports and load conditions. The obtained computation results allow to observe bend and strains in material of dental bridges, evaluated reaction forces allow to estimate loads of pillar teeth. The analysis was performed in commercial program ANSYS, with the use of special prepared batch file in order to ease the parametrical analysis for different boundary, loads conditions and geometrical dimension of bridges (cross-section and span of dentures bridges length).

11

Strength analysis of reinforcement of dental bridges of anterior teeth prostheses

Milewski G., Kromka M., Repeta P.

Zeszyty Naukowe Katedry Mechaniki Stosowanej / Politechnika Śląska

|

2006

|

z. 26

247-252

EN

Application of strengthening elements in dental bridges for both fixed and removable prostheses essentially extends possibilities of lost teeth reconstruction as well as increases the range of transfered occlusal loadings. The paper presents comparative numerical analysis of the reinforced polymer-based fixed prosthesis used for a reconstruction of the total teeth lack in anterior mandibular part. The strengthening bars of various cross-sections were made of stainless steel, titanic alloy, ceramics and glass composite. The stress distributions in the elements of prostheses as well as the analysis of effort in the mandibular bone structures close to the supporting pillars have been done for the case of bite occlusal loadings.