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Journal of Prosthodontics : Official... Jun 2015The aim of this study was to review the effect of selective laser melting (SLM) procedure on the properties of dental structures made of Co-Cr alloys and to evaluate its... (Review)
Review
PURPOSE
The aim of this study was to review the effect of selective laser melting (SLM) procedure on the properties of dental structures made of Co-Cr alloys and to evaluate its quality and compare it to those produced by conventional casting and milling fabrication techniques.
MATERIALS AND METHODS
A computerized database search using PubMed and Scopus was conducted for peer-reviewed scientific research studies regarding the use of SLM in Co-Cr dental alloys with no restrictions for publication years. The search engines provided hundreds of results, and only 48 scientific research papers, case studies, or literature reviews were considered relevant for this review.
RESULTS
The innovative manufacturing concept of SLM offers many advantages compared with casting and milling fabrication techniques. SLM provides different microstructure from casting and milling with minimal internal porosity and internal fitting, marginal adaptation, and comparable bond strength to porcelain. Mechanical and electrochemical properties of SLM structures are enhanced compared to cast, while clinical longevity of single-metal ceramic crowns is comparable to Au-Pt dental alloy.
CONCLUSION
The SLM technique provides dental prosthetic restorations more quickly and less expensively without compromising their quality compared with restorations prepared by casting and milling techniques.
CLINICAL SIGNIFICANCE
The current SLM devices provide metallic restorations made of Co-Cr alloys for removable and fixed partial dentures without compromising the alloy or restoration properties at a fraction of the time and cost, showing great potential to replace the aforementioned fabrication techniques in the long term; however, further clinical studies are essential to increase the acceptance of this technology by the worldwide dental community.
Topics: Chromium Alloys; Dental Alloys; Dental Casting Technique; Dental Porcelain; Humans; Materials Testing; Metal Ceramic Alloys; Surface Properties
PubMed: 26129918
DOI: 10.1111/jopr.12268 -
The cytotoxic and oxidative effects of restorative materials in cultured human gingival fibroblasts.Drug and Chemical Toxicology Sep 2021The aim of this study was to evaluate the cytotoxic and oxidative effects of the most commonly used dental restorative materials on human gingival fibroblast cells... (Comparative Study)
Comparative Study
The aim of this study was to evaluate the cytotoxic and oxidative effects of the most commonly used dental restorative materials on human gingival fibroblast cells (HGFCs). HGFCs were obtained from healthy individuals. The tested restorative materials were a microhybrid resin based composite, a compomer resin, a glass ionomer cement, and an amalgam alloy. One hundred eight cylindirical samples, 10 mm in diameter and 2 mm in height, were prepared according to ISO 10993-12:2002 specifications ( = 9 in the tested subgroups). Freshly prepared and aged samples in artificial saliva at 37 °C (7 and 21 d) were placed into well plates and incubated. Wells without dental materials were constituted as the control group. After 72 h incubation period, cytotoxicity was determined using the neutral red (NR) assay. Oxidative alterations were assessed using total antioxidant capacity (TAC) and total oxidant status (TOS) assay kits. Data were analyzed using the ANOVA and LSD post hoc tests. All tested materials led to significant decreases in the cell viability rates (33-73%) compared to the control group. Glass ionomer and resin composite were found to be more cytotoxic than amalgam alloy and compomer. The highest TAC level was observed in glass ionomer after seven-day aging and these changes prevented an increase in TOS levels. Increases in TAC levels after seven-day aging in all groups exhibited significant differences with freshly prepared samples ( < 0.05). In all material groups, TOS levels of freshly prepared samples differed statistically and significantly from samples aged for 7 and 21 d ( < 0.05). The data obtained suggested that all the tested materials exhibited cytotoxic and pro-oxidant features. Freshly prepared samples caused higher TOS levels. However, oxidant status induced by materials decreased over time.
Topics: Cells, Cultured; Compomers; Composite Resins; Dental Alloys; Dental Amalgam; Dental Cements; Fibroblasts; Gingiva; Glass Ionomer Cements; Humans; Materials Testing; Oxidative Stress; Saliva; Time Factors
PubMed: 31146597
DOI: 10.1080/01480545.2019.1620265 -
International Endodontic Journal Apr 2023To compare design, metallurgy and mechanical performance of the ProTaper (PT) Ultimate system with instruments of similar dimensions from the ProGlider, PT Gold and PT...
AIM
To compare design, metallurgy and mechanical performance of the ProTaper (PT) Ultimate system with instruments of similar dimensions from the ProGlider, PT Gold and PT Universal systems.
METHODOLOGY
New PT Ultimate instruments (n = 248) were compared with instruments of similar dimensions from ProGlider (n = 31), PT Gold (n = 155) and PT Universal (n = 155) systems regarding their number of spirals, helical angle, blade symmetry, tip geometry, surface finishing, nickel/titanium ratio, phase transformation temperatures and mechanical performance. One-way anova and nonparametric Mood's median tests were used for statistical comparison (α = 5%).
RESULTS
All instruments had symmetrical blades without radial lands or flat sides, similar surface finishing and an almost equiatomic nickel/titanium ratio, whilst the number of spirals, helical angles and the tip geometry were different. PT Ultimate instruments showed 3 distinct heat treatments that matched with the colour of their metal wire. Slider and ProGlider instruments had similar R-phase start (Rs) and R-phase finish (Rf) temperatures. SX, F1, F2, F3 and Shaper instruments showed equivalent heat treatments (Rs ~45.6°C and Rf ~28.3°C) that were similar to their PT Gold counterparts (Rs ~47.9°C and Rf ~28.2°C), but completely distinct to the PT Universal ones (Rs ~16.2°C and Rf ~-18.2°C). Amongst the PT Ultimate instruments, the lowest maximum torques were observed in the SX (0.44 N cm), Slider (0.45 N cm) and Shaper (0.60 N cm) instruments, whilst the highest was noted in the FXL (4.90 N cm). PT Ultimate Slider and ProGlider had similar torsional (~0.40 N cm) and bending loads (~145.0 gf) (p = 1.000), whilst the other PT Ultimate instruments showed statistically significantly lower maximum torque, higher angle of rotation and lower bending load (higher flexibility) than their counterparts of the PT Universal and PT Gold systems.
CONCLUSIONS
The PT Ultimate system comprises instruments with 3 distinct heat treatments that showed similar phase transformation temperatures to their heat-treated analogues. PT Ultimate instruments presented lower torsional strength and superior flexibility than their counterparts, whilst maximum torque, angle of rotation and bending loads progressively increased with their sizes.
Topics: Titanium; Nickel; Hot Temperature; Equipment Failure; Materials Testing; Dental Alloys; Root Canal Preparation; Equipment Design; Torsion, Mechanical
PubMed: 36508297
DOI: 10.1111/iej.13880 -
The Journal of Prosthetic Dentistry Apr 2019Electron backscatter radiation from dental materials can contribute to soft tissue injury in patients undergoing head and neck radiation therapy.
STATEMENT OF PROBLEM
Electron backscatter radiation from dental materials can contribute to soft tissue injury in patients undergoing head and neck radiation therapy.
PURPOSE
The dose enhancement from the materials used for prosthodontic restoration of the dentition has not been well quantified. This study reports the magnitude of backscatter dose from the contemporary dental materials lithium disilicate and zirconia as compared with high-noble alloy and investigates the role of a spacer material in mitigating this effect.
MATERIAL AND METHODS
Three flat slabs of dental materials high-noble alloy, lithium disilicate, and zirconia with thicknesses of 1.5 and 3 mm were irradiated with 6-MV photons from a clinical linear accelerator. Measurements were made using a thin-window parallel-plate ionization chamber placed at 0, 1, 3, and 5 mm from the material. One millimeter of poly(methyl methacrylate) or thermoplastic material was used to cover the dental material and measure the effect on the adjacent dose enhancement.
RESULTS
Dose enhancements between 8% and 50% were recorded adjacent to the dental restoration materials. The largest enhancements occurred for the material of the highest density, the high-noble alloy. Dose enhancement was substantially lower for lithium disilicate (8%) and zirconia (30%). The thickness of the restoration material did not significantly affect dose enhancement. The dose enhancement decreased with distance from the material, dropping to <10% for all materials at 3 mm.
CONCLUSIONS
Contemporary dental restorations enhance the backscatter dose. The presence of dental restorations may warrant the use of a stent to create separation from these materials as this can mitigate the effect.
Topics: Dental Alloys; Dental Materials; Dental Porcelain; Dental Prosthesis Design; Humans; Materials Testing; Radiation Dosage; Zirconium
PubMed: 30580980
DOI: 10.1016/j.prosdent.2018.07.012 -
Journal of the National Medical... Jun 2018The purpose of this study was to evaluate the two-body wear resistances of natural enamel and four dental materials in vitro.
INTRODUCTION
The purpose of this study was to evaluate the two-body wear resistances of natural enamel and four dental materials in vitro.
METHODS
The testing machine was modified to form a type of pin-on-disk wear test apparatus. Four dental material specimens (Au-Pd alloy, Ag-Pd alloy, FiltekTMP60 and FiltekTMZ350 composite resins) and enamel were used as the pins, and a steatite ceramic grinding wheel was used as the abrasive counter face. The wear volume loss and the rigidity value was measured. The worn surface and the element analysis of the debris were analyzed.
RESULT
The wear volume loss of Au-Pd alloy and its steatite antagonists were the nearest to those of the dental enamel. SEM microphotographs showed that, the main wear mechanism of the dental materials was abrasive and adhesive wear.
CONCLUSIONS
Au-Pd alloy had good wear resistance and was more suitable for dental applications than other three dental materials.
Topics: Composite Resins; Dental Alloys; Dental Enamel; Dental Materials; Dental Restoration Wear; Humans; Materials Testing; Surface Properties
PubMed: 29778127
DOI: 10.1016/j.jnma.2017.05.009 -
Dental Materials Journal Jun 2020The aim of this study was to construct a Ti-Nb-Cu ternary phase diagram that plays the role of a map for developing new titanium alloys with excellent machinability and...
The aim of this study was to construct a Ti-Nb-Cu ternary phase diagram that plays the role of a map for developing new titanium alloys with excellent machinability and mechanical properties. Fifteen experimental Ti-Nb-Cu ternary alloys composed of Ti-5-30%Nb-2-20%Cu were designed, and ingots made using Ar-arc melting furnace before casting to generate specimen. The alloy castings were evaluated in terms of their microstructures and alloy phases. A Ti-Nb-TiCu pseudo-ternary phase diagram was constructed using X-ray diffractmetry results. Three alloy phases (α-Ti, β-Ti and TiCu) were established within the specimen. Furthermore, the prescence of two-phase coexistence regions (α+TiCu, α+β and β+TiCu), and three-phase coexistence region (α+β+TiCu) was noted. The findings obtained through microstructural observation corresponded well with the constructed phase diagram.
Topics: Alloys; Dental Alloys; Titanium; X-Ray Diffraction
PubMed: 31969544
DOI: 10.4012/dmj.2018-394 -
Journal of the Mechanical Behavior of... Dec 2020In this study, two medium Zr-containing Ti-based alloys with commercially pure titanium as control were systematically investigated to assess their potential biomedical...
In this study, two medium Zr-containing Ti-based alloys with commercially pure titanium as control were systematically investigated to assess their potential biomedical application. After samples subjected to TMP and CR, it was found that the Zr addition significantly affected the microstructure, phase constitutions, mechanical properties and cytocompatibility. The microstructural results showed that increasing Zr concentrations resulted in more refined grains. Furthermore, Zr changed the phase constitution: CR Ti-20Zr was formed by the single α-phase while CR Ti-30Zr alloy was formed by the coexistence of α and deformation-induced FCC phases. The P-type FCC phase was dominant and more prone to occur than the B-type one. The mechanical tests demonstrated that the increasing Zr content led to a simultaneous increase in micro-hardness, strength and plasticity of CR samples due to the combined effects of solution strengthening, work hardening and the FCC phase. The SEM fractography indicated that the brittle fracture of CR Ti-20Zr due to deformation twins and ductile fracture of CR Ti-30Zr because of FCC phase. Furthermore, Ti-Zr alloys presented comparable cytocompatibility to the CP-Ti control based on cell viability, proliferation and intracellular O content of MSCs. Specifically, alkaline phosphatase activity in BMSCs were significantly higher for grain refined CR Ti-30Zr. Considering all these results, CR Ti-30Zr alloy exhibited the optimal comprehensive performance to be potential dental materials.
Topics: Alloys; Biocompatible Materials; Dental Alloys; Hardness; Materials Testing; Titanium
PubMed: 32920276
DOI: 10.1016/j.jmbbm.2020.104048 -
Dental Materials : Official Publication... Aug 2022Titanium (Ti) is considered bioinert and is still regarded as the "gold standard" material for dental implants. However, even 'commercial pure' Ti will contain minor...
OBJECTIVE
Titanium (Ti) is considered bioinert and is still regarded as the "gold standard" material for dental implants. However, even 'commercial pure' Ti will contain minor fractions of elemental impurities. Evidence demonstrating the release of Ti ions and particles from 'passive' implant surfaces is increasing and has been attributed to biocorrosion processes which may provoke immunological reactions. However, Ti observed in peri-implant tissues has been shown to be co-located with elements considered impurities in biomedical alloys. Accordingly, this study aimed to quantify the composition of impurities in commercial Ti dental implants.
METHODS
Fifteen commercial titanium dental implant systems were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS) and optical emission spectrometry (ICP-OES).
RESULTS
The elemental composition of implants manufactured from commercially pure grades of Ti, Ti-6Al-4V, and the TiZr alloy (Roxolid) conformed to the respective ISO/ASTM standards or manufacturers´ data (TiZr/Roxolid). However, all implants investigated included exogenous metal contaminants including Ni, Cr, Sb, and Nb to a variable extent. Other contaminants detected in a fraction of implants included As and the radionuclides U-238 and Th-232.
SIGNIFICANCE
Although all Ti implant studies conformed with their standard compositions, potentially allergenic, noxious metals and even radionuclides were detected. Since there are differences in the degree of contamination between the implant systems, a certain impurity fraction seems technically avoidable. The clinical relevance of these findings must be further investigated, and an adaptation of industry standards should be discussed.
Topics: Alloys; Dental Alloys; Dental Implants; Spectrum Analysis; Surface Properties; Titanium; Uranium
PubMed: 35781168
DOI: 10.1016/j.dental.2022.06.028 -
Current Topics in Medicinal Chemistry 2015At present, the use of dental implants is a very common practice as tooth loss is a frequent problem and can occur as a result of disease or trauma. An implant is... (Review)
Review
At present, the use of dental implants is a very common practice as tooth loss is a frequent problem and can occur as a result of disease or trauma. An implant is usually made of biocompatible materials that do not cause rejection reactions and allow the implant union with the respective bone. To achieve this goal, the implant surface may have different structures and coatings, generally used to increase the adherence of the implant to the bone and to decrease the risk of the periimplantar inflammatory reactions. This review gives some insights of the metal based materials used for dental implants, their limits, improvement strategies as well as the pathophysiology, diagnosis, treatment and prevention of periimplantary diseases.
Topics: Biocompatible Materials; Dental Alloys; Dental Implants; Humans; Peri-Implantitis
PubMed: 25877088
DOI: 10.2174/1568026615666150414144033 -
Odontology Apr 2018The current study aimed at examining surface and chemical composition changes of retrieved mini-implants after different periods of service as aids of anchorage for...
The current study aimed at examining surface and chemical composition changes of retrieved mini-implants after different periods of service as aids of anchorage for orthodontic patients. This study examined 72 retrieved orthodontic self-tapping and self-drilling mini-implants, 1.7 mm in diameter and 8 mm in length (OrthoEasy system, Forestadent, Pforzheim, Germany) from 36 adult orthodontic patients (18 men and 18 women, mean age = 23 years). The retrieved mini-implants were divided into 3 groups according to service period: 3-6 months (3M-6M) group, 6-12 months (6M-12M) group, and 12-24 months (12M-24M) group, with 24 mini-implants in each group. The control group (As Received) comprised of 24 unused mini-implants of the same type (AR group). All mini-implant heads and threaded bodies were examined for chemical characterization and topographical features by SEM-EDS. The average weight percentages for the following elements Ti, Al, and O were obtained and compared among the 4 groups. There was significant decrease in titanium content and deterioration for the surface properties for all parts of the mini-implants after being used inside patients' oral cavities for more than 6 months p < 0.05. The period of mini-implant service inside patients' oral cavities should not exceed 6 months.
Topics: Dental Alloys; Dental Implants; Dental Prosthesis Design; Dental Restoration Failure; Female; Humans; Male; Materials Testing; Microscopy, Electron, Scanning; Orthodontic Anchorage Procedures; Surface Properties; Time Factors; Young Adult
PubMed: 28840411
DOI: 10.1007/s10266-017-0319-0