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Journal of the Mechanical Behavior of... May 2024Peri-implantitis and insufficient osseointegration are the principal challenges faced by dental implants at present. In order to fabricate dual-function dental implant...
Peri-implantitis and insufficient osseointegration are the principal challenges faced by dental implants at present. In order to fabricate dual-function dental implant materials possessing both antibacterial and osteogenic capabilities, this study incorporates the antimicrobial element Cu into the Ti40Nb alloy, developing a novel Ti40Nb-xCu alloy with antibacterial properties. Among them, Ti40Nb3Cu has the best overall performance. Compared to Ti40Nb, the tensile strength increased by 27.97%, reaching 613 MPa. Although the elongation rate has decreased from 23% to 13.5%, the antibacterial rates against S. aureus and P. gingivalis both exceed 85%. Furthermore, the surface of Ti40Nb-xCu alloy was then treated with micro-arc oxidation to enhance its bioactivity, thereby accelerating osseointegration. The results indicated that the MAO treatment retains the antibacterial properties of the Ti40Nb3Cu alloy while significantly promoting bone formation through its introduced porous coating, thus heralding it as a propitious candidate material for dental implant applications.
PubMed: 38852242
DOI: 10.1016/j.jmbbm.2024.106605 -
Journal of Long-term Effects of Medical... 2024This virtual study was designed to evaluate the stress-deformation of a metal fixed partial dentures (FPDs) pontic under different loads using two different connectors....
This virtual study was designed to evaluate the stress-deformation of a metal fixed partial dentures (FPDs) pontic under different loads using two different connectors. The STL file was generated for a RPD of two implant-supported restorations. The Co-Cr metal substructure was designed with two types of connector design. The pontic is connected to implant-supported crowns with square and round shape connectors. This study was designed for a cementless-retained implant-supported FPD. Finite element modeling (FEM) is used to assess the stress and deformation of the pontic within a metal substructure as the FEM might provide virtual values that could have laboratory and clinical relevance. The Co-Cr alloy mechanical properties like the Poisson ratio and modulus of elasticity were based on the parameters of the three-dimensional structure additive method. Nonparametric analyses (Mann-Whitney U test) was used. The use of square or round connectors often resulted in non-significant changes in stress, and deformation under either three or each loaded point on the occlusal surface of a pontic (P > 0.05). However, the deformation revealed distinct variations between loads of the three points compared to each loaded point (P ≤ 0.05). According to this study data, the pontic occlusal surface appears to be the same in stress and deformation under different loads depending on whether square or round connectors are used. While at the same connector designs, the pontic occlusal surface deformed significantly at three loaded points than it did at each point.
Topics: Finite Element Analysis; Denture, Partial, Fixed; Dental Prosthesis, Implant-Supported; Humans; Chromium Alloys; Denture Design; Dental Stress Analysis; Stress, Mechanical
PubMed: 38842231
DOI: 10.1615/JLongTermEffMedImplants.2023048378 -
The Journal of Evidence-based Dental... Jun 2024The primary aim was to investigate survival rate of zirconia versus metal abutments, and the secondary aim was clinical outcomes of all-ceramic versus metal-ceramic...
OBJECTIVES
The primary aim was to investigate survival rate of zirconia versus metal abutments, and the secondary aim was clinical outcomes of all-ceramic versus metal-ceramic crowns on single-tooth implants.
METHODS
Patients with tooth-agenesis participated to previously published prospective clinical study with 3-year follow-up were recalled after 5 years. Biological variables included survival and success rate of implants, marginal bone level, modified Plaque and Sulcus Bleeding Index and biological complications. Technical variables included restoration survival rate, marginal adaptation and technical complications. The aesthetic outcome of crowns and peri-implant mucosa in addition to patient-reported outcome were recorded. Descriptive analysis, linear mixed model for quantitative data, or generalized linear mixed model for ordinal categorical data were applied; significance was set to 0.05.
RESULTS
Fifty-three patients (mean age: 32.4 years), with 89 implants participated to the 5-years examination. The implants supported 50 zirconia abutments with 50 all-ceramic (AC) crown and 39 metal abutments with 29 metal-ceramic (MC) and 10 AC crowns. The Implant and restoration survival rate was 100% and 96%, respectively. No clinically relevant biological difference between implants supporting metal or zirconia abutments was registered. The technical complications were veneering fracture of AC-crowns (n = 3), crown loosening of MC-crowns (n = 4) and one abutment screw loosening (MC-crown on metal abutment). MC-crowns had significantly better marginal adaptation than AC-crowns (p = .01). AC-crowns had significantly better color and morphology than MC-crowns (p = .01).
CONCLUSIONS
Zirconia-based single-tooth restorations are reliable alternative materials to metal-based restorations with favorable biological and aesthetic outcome, and few technical complications.
Topics: Humans; Zirconium; Prospective Studies; Female; Male; Adult; Dental Implants, Single-Tooth; Dental Prosthesis, Implant-Supported; Crowns; Dental Abutments; Dental Restoration Failure; Middle Aged; Anodontia; Young Adult; Metal Ceramic Alloys; Esthetics, Dental
PubMed: 38821661
DOI: 10.1016/j.jebdp.2024.101970 -
The International Journal of... Feb 2024The purpose of this systematic review and meta-analysis was to compare the influence of fabrication method (conventional, subtractive, and additive procedures) and... (Meta-Analysis)
Meta-Analysis
Influence of the Manufacturing Trinomial (Technology, Printer, and Material) on the Marginal and Internal Discrepancies of Printed Metal Frameworks for the Fabrication of Tooth-Supported Prostheses: A Systematic Review and Meta-analysis.
PURPOSE
The purpose of this systematic review and meta-analysis was to compare the influence of fabrication method (conventional, subtractive, and additive procedures) and manufacturing trinomial (technology, printer, and material combination) on the marginal and internal fit of cobaltchromium (Co-Cr) tooth-supported frameworks.
MATERIALS AND METHODS
An electronic systematic review was performed in five data bases: MEDLINE/PubMed, Embase, World of Science, Cochrane, and Scopus. Studies that reported the marginal and internal discrepancies of tooth-supported Co-Cr additive manufacturing (AM) frameworks were included. Two authors independently completed the quality assessment of the studies by applying the Joanna Briggs Institute Critical Appraisal Checklist for Quasi-Experimental Studies. A third examiner was consulted to resolve lack of consensus.
RESULTS
A total of 31 articles were included and classified based on the evaluation method: manufacturing accuracy, the dual- or triple-scan method, stereomicroscope, optical coordinate measurement machine, microCT, profilometer, and silicone replica. Six subgroups were created: 3D Systems, Bego, Concept Laser, EOS, Kulzer, and Sisma. Due to the heterogeneity and limited data available, only the silicone replica group was considered for meta-analysis. The metaanalysis showed a mean marginal discrepancy of 91.09 μm (I2 = 95%, P < .001) in the conventional group, 77.48 μm (I2 = 99%, P < .001) in the milling group, and 82.92 μm (I2 = 98%, P < .001) in the printing group. Additionally, a mean internal discrepancy of 111.29 μm (I2 = 94%, P < .001) was obtained in the conventional casting group, 121.96 μm (I2 = 100%, P < .001) in the milling group, and 121.25 μm (I2 = 99%, P < .001) in the printing group.
CONCLUSIONS
Manufacturing method and selective laser melting (SLM) metal manufacturing trinomial did not impact the marginal and internal discrepancies of Co-Cr frameworks for the fabrication of tooth-supported restorations.
Topics: Humans; Computer-Aided Design; Chromium Alloys; Dental Marginal Adaptation; Printing, Three-Dimensional; Denture Design; Dental Prosthesis Design; Technology, Dental; Dental Materials
PubMed: 38819942
DOI: 10.11607/ijp.8830 -
Journal of Biomedical Materials... Jun 2024Cobalt-Chromium (CoCr) alloys are currently used for various cardiovascular, orthopedic, fracture fixation, and dental implants. A variety of processes such as casting,... (Review)
Review
Cobalt-Chromium (CoCr) alloys are currently used for various cardiovascular, orthopedic, fracture fixation, and dental implants. A variety of processes such as casting, forging, wrought processing, hot isostatic pressing, metal injection molding, milling, selective laser melting, and electron beam melting are used in the manufacture of CoCr alloy implants. The microstructure and precipitates (carbides, nitrides, carbonitrides, and intermetallic compounds) formed within the alloy are primarily determined by the type of manufacturing process employed. Although the effects of microstructure and precipitates on the physical and mechanical properties of CoCr alloys are well reviewed and documented in the literature, the effects on corrosion resistance and biocompatibility are not comprehensively reviewed. This article reviews the various processes used to manufacture CoCr alloy implants and discusses the effects of manufacturing processes on corrosion resistance and biocompatibility. This review concludes that the microstructure and precipitates formed in the alloy are unique to the manufacturing process employed and have a significant impact on the corrosion resistance and biocompatibility of CoCr alloys. Additionally, a historical and scientific overview of corrosion and biocompatibility for metallic implants is included in this review. Specifically, the failure of CoCr alloys when used in metal-on-metal bearing surfaces of total hip replacements is highlighted. It is recommended that the type of implant/application (orthopedic, dental, cardiovascular, etc.) should be the first and foremost factor to be considered when selecting biomaterials for medical device development.
Topics: Humans; Corrosion; Chromium Alloys; Materials Testing; Animals; Biocompatible Materials; Prostheses and Implants
PubMed: 38817036
DOI: 10.1002/jbm.b.35431 -
The European Journal of Prosthodontics... May 2024The surface properties of titanium dental implants, such as wettability and surface free energy, influence the adhesion of microorganisms responsible for inflammation...
The surface properties of titanium dental implants, such as wettability and surface free energy, influence the adhesion of microorganisms responsible for inflammation and infection of peri-implant tissues. This systematic review aimed to investigate the relationship of titanium surface treatments, surface free energy/wettability property and its relationship with bacterial activity. This systematic review followed PRISMA 2020 (Preferred Reporting Items for Systematic Review and MetaAnalysis) guidelines and was registered in the OpenScience Framework (osf.io/ejnct). PubMed, ScienceDirect, Embase, and Scopus library databases were used from custom search strategies. Inclusion criteria were research articles that studied titanium or its alloys for wetting property and its correlation with adhesion. Of the 697 articles initially identified, 27 were selected after full-text reading and application of the eligibility criteria. In general, the evaluated studies showed that regardless of the surface treatment, there was an increase in titanium hydrophilicity and concomitant reduction in bacterial adhesion. The surface treatment of titanium results in higher surface free energy and lower bacterial adhesion. Hydrophilic titanium surfaces prevent adhesion of hydrophobic bacteria in early stages.
PubMed: 38809699
DOI: 10.1922/EJPRD_2609Soares12 -
Journal of the Mechanical Behavior of... Aug 2024The aim of this study is to compare the stress distribution in porous scaffolds with different structures with similar geometric parameters to study a new approach in... (Comparative Study)
Comparative Study
The aim of this study is to compare the stress distribution in porous scaffolds with different structures with similar geometric parameters to study a new approach in dental implantation. Three-dimensional finite element models of the fully porous and dense-core porous scaffolds with defined porosity parameters including space diameter and thickness with two porosity patterns were embedded in the jaw bone model with cortical and cancellous bone. The cylindrical shape was considered as the main shape of the scaffolds. To evaluate the mechanical performance, the Von Mises stress was compared in the models under static and dynamic masticatory loading. Incidentally, to validate the modeling results, experimental strain gauge tests were performed on four specimens fabricated from Ti6Al4V. Finally, the stress distribution in the models was compared with the results of previous studies on commercial implants. The results of the finite element analysis show that there are considerable differences in the magnitude of the equivalent stress in the models in static and dynamic phases. Also, changes in the defined geometric parameters have significant effects on the stress distribution in terms of Von Mises stress in the overall models. The experimental results indicated good agreement with those of the modeling. It can be concluded that some porous structures with optimal geometries can be proposed as a new structure for dental implants. However, considering the physiology of bone when confronted with porous structures, further studies such as in vivo experiments are needed in this field.
Topics: Porosity; Stress, Mechanical; Finite Element Analysis; Materials Testing; Alloys; Dental Implantation; Titanium; Dental Implants; Tissue Scaffolds; Mechanical Tests
PubMed: 38805873
DOI: 10.1016/j.jmbbm.2024.106602 -
The Journal of Prosthetic Dentistry May 2024Excellent optical properties are essential for esthetic dental materials. However, the translucency and color masking ability of zirconia fabricated with nanoparticle...
STATEMENT OF PROBLEM
Excellent optical properties are essential for esthetic dental materials. However, the translucency and color masking ability of zirconia fabricated with nanoparticle jetting (NPJ), a type of printed zirconia, are unknown.
PURPOSE
The purpose of this in vitro study was to evaluate the translucency and color masking ability of zirconia fabricated using NPJ.
MATERIAL AND METHODS
A total of 90 specimens with thicknesses of 1.5, 1.0, and 0.5 mm were fabricated using high translucent milled zirconia (HT), low translucent milled zirconia (LT), and NPJ. CIELab values (L*, a*, and b*) of the specimens over 7 backgrounds, black, white, VitaB1, VitaA2, VitaA4, gold alloy (Au), and titanium (Ti), were obtained using a spectral radiometer. The relative translucency parameter (RTP) and color difference (∆E) of specimens over VitaB1, VitaA4, Au, and Ti were determined using VitaA2 as the control with the CIEDE2000 color difference equation. The normality of the data distribution was determined using the Shapiro-Wilk test. Differences among groups were analyzed using 2-way analysis of variance and the Student-Newman-Keuls (SNK) post hoc test (α=.05). The ∆E of specimens was analyzed according to perceptibility (∆E=0.8) and acceptability (∆E=1.8) thresholds using the 1 sample t test. The correlation between RTP and ∆E and RTP/∆E and thickness was examined using the Pearson correlation analysis.
RESULTS
Statistically significant differences were observed in translucency and color masking ability among HT, LT, and NPJ (P<.05). The RTP value was the lowest for zirconia fabricated with NPJ (P<.001) and highest for HT (P<.001). Monolithic zirconia fabricated with NPJ had lower ∆E values than those of HT and LT for the same thickness and background (P<.05). A positive correlation was found in RTP and ∆E (P<.001). A negative correlation was observed in RTP and thickness (P<.001) and ∆E and thickness across a constant background (P<.001).
CONCLUSIONS
Zirconia fabricated with NPJ was less translucent and had a greater color masking ability for discolored backgrounds than HT and LT.
PubMed: 38796354
DOI: 10.1016/j.prosdent.2024.05.005 -
Materials (Basel, Switzerland) May 2024Chromium- and cobalt-based alloys, as well as chrome-nickel steels, are most used in dental prosthetics. Unfortunately, these alloys, especially nickel-based alloys, can...
Chromium- and cobalt-based alloys, as well as chrome-nickel steels, are most used in dental prosthetics. Unfortunately, these alloys, especially nickel-based alloys, can cause allergic reactions. A disadvantage of these alloys is also insufficient corrosion resistance. To improve the properties of these alloys, amorphous Si (C,N) coatings were deposited on the surfaces of metal specimens. This paper characterizes coatings of silicon carbide nitrides, deposited by the magnetron sputtering method on the surface of nickel-chromium alloys used in dental prosthetics. Depending on the deposition parameters, coatings with varying carbon to nitrogen ratios were obtained. The study analyzed their structure and chemical and phase composition. In addition, a study of surface wettability and surface roughness was performed. Based on the results obtained, it was found that amorphous coatings of Si (C,N) type with thicknesses of 2 to 4.5 µm were obtained. All obtained coatings increase the value of surface free energy. The study showed that Si (C,N)-type films can be used in dental prosthetics as protective coatings.
PubMed: 38793515
DOI: 10.3390/ma17102450 -
Materials (Basel, Switzerland) May 2024The resistance of nickel-titanium endodontic instruments against cyclic fatigue failure remains a significant concern in clinical settings. This study aimed to assess...
The resistance of nickel-titanium endodontic instruments against cyclic fatigue failure remains a significant concern in clinical settings. This study aimed to assess the cyclic fatigue strength of five nickel-titanium rotary systems, while correlating the results with the instruments' geometric and metallurgical characteristics. A total of 250 new instruments (sizes S1/A1, S2/A2, F1/B1, F2/B2, F3/B3) from ProTaper Gold, ProTaper Universal, Premium Taper Gold, Go-Taper Flex, and U-Files systems underwent mechanical testing. Prior to experimental procedures, all instruments were meticulously inspected to identify irregularities that could affect the investigation. Using a stereomicroscope, design characteristics such as the number of spirals, length, spirals per millimeter, and average helical angle of the active blade were determined. The surface finishing characteristics of the instruments were examined using a scanning electron microscope. Differential scanning calorimetry was employed to establish the instruments' phase transformation temperatures, while energy-dispersive X-ray spectroscopy was utilized to analyze the elemental composition of the alloy. The instruments were subjected to cyclic fatigue testing within a stainless steel non-tapered artificial canal featuring a 6 mm radius and 86 degrees of curvature. Appropriate statistical tests were applied to compare groups, considering a significance level of 0.05. The assessed design characteristics varied depending on the instrument type. The least irregular surface finishing was observed in U-Files and Premium Taper Gold files, while the most irregular surface was noted in Go-Taper Flex. All instruments exhibited near-equiatomic proportions of nickel and titanium elements, whereas ProTaper Universal and U-Files instruments demonstrated lower phase transformation temperatures compared to their counterparts. Larger-sized instruments, as well as ProTaper Universal and U-Files, tended to display lower cyclic fatigue strength results. Overall, the design, metallurgical, and cyclic fatigue outcomes varied among instruments and systems. Understanding these outcomes may assist clinicians in making more informed decisions regarding instrument selection.
PubMed: 38793413
DOI: 10.3390/ma17102345