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Toxicology and Applied Pharmacology Nov 2019The aim was to explore the biological effect of nickel (Ni) and titanium (Ti) ions released from dental alloys. NiTi alloy were exposed to 40 mL of artificial saliva...
The aim was to explore the biological effect of nickel (Ni) and titanium (Ti) ions released from dental alloys. NiTi alloy were exposed to 40 mL of artificial saliva (pH = 4.8, t = 37 °C). The dynamics of Ni and Ti ions release during corrosion were recorded on the 3th, 7th and 14th day. Biological effect of Ni and Ti ions released from alloy was explored on cell lines of human tongue CAL 27, liver Hep G2 and colon Caco-2. Neutral Red uptake assay for the estimation of cell viability/cytotoxicity and 2',7'-dichlorofluorescein diacetate fluorimetric assay for reactive oxygen species were used. Cells were exposed to the following concentration of corrosion products: 5.0×, 1.0×, 0.5 and 0.1× during the period of 24, 48 and 72 h. To check the effect of each metal separately, cells were exposed to nickel-chloride and titanium-dioxide of corresponding concentration. The release of Ni is higher than of Ti (15.1-30.4 μg/L for Ni and 9.0-17.3 μg/L for Ti, respectively) and 5× higher concentrations are needed to induce cytotoxic effect. Ni and Ti ions alone do not induce a major cytotoxic effect, but their combination does indicating their synergistic effect. Increase in concentration of Ni and Ti tends to increase cytotoxicity, Ti more than Ni. Cytotoxicity and induction of free radicals are in strong positive linear correlation. Ions released from NiTi alloy during 14 days do not induce significant cytotoxic effect and would not have a clinically important impact. Cytotoxic effect is largely the result of the induction of free radicals.
Topics: Caco-2 Cells; Cell Survival; Cytotoxins; Dental Alloys; Gastrointestinal Tract; Hep G2 Cells; Humans; Materials Testing; Nickel; Oxidative Stress; Saliva; Titanium
PubMed: 31628918
DOI: 10.1016/j.taap.2019.114784 -
International Endodontic Journal Jun 2023This study aimed to compare three rotary instruments produced by the EDM process with the heat-treated ProTaper Gold system regarding design, metallurgy, mechanical...
AIM
This study aimed to compare three rotary instruments produced by the EDM process with the heat-treated ProTaper Gold system regarding design, metallurgy, mechanical properties and shaping ability.
METHODOLOGY
HyFlex EDM (25/~), Neoniti (25/.06), EDMax (25/.06) and ProTaper Gold (25/.08v) instruments (n = 58 per group) were compared regarding design, metallurgy and mechanical performance. Unprepared canal areas were calculated for each system after preparation of mesiobuccal, mesiolingual and distal canals of mandibular molars (15 canals per group) using micro-CT technology. Statistical analyses were performed using One-way anova post-hoc Tukey and Kruskal-Wallis post-hoc Dunn's tests (α = 5%).
RESULTS
All instruments had asymmetrical blades, no radial lands, no major defects and almost equiatomic nickel/titanium ratios, but different cross-section designs, tip geometries and surface appearances. Although instruments had distinct transformation temperature curves, they showed crystallographic martensitic arrangement at 21°C and mixed austenite plus R-phase at body temperature. Neoniti and HyFlex EDM showed similar results in all mechanical tests (p > .05), while EDMax and ProTaper Gold had similar time to fracture (p = .841), maximum bending load (p = .729), and cutting ability (p = .985). ProTaper Gold showed the highest torque to failure (p < .001) and HyFlex EDM had the lowest buckling resistance (p < .001). Mean percentages of unprepared canal areas ranged from 20.4% to 25.7% in the mesial canals, and from 20.8% to 26.2% in the distal canal, with no statistical differences among systems (p > .05).
CONCLUSIONS
Instruments' geometry and phase transformation temperatures influenced the results of the mechanical tests, but not their shaping ability.
Topics: Humans; Dental Alloys; Dental Instruments; Equipment Design; Materials Testing; Root Canal Preparation; Temperature; Titanium; Torque
PubMed: 36942476
DOI: 10.1111/iej.13915 -
Journal of Endodontics Sep 2021This study aimed to compare the torque generated by 4 different files in root canals with 4 different curvature angles.
INTRODUCTION
This study aimed to compare the torque generated by 4 different files in root canals with 4 different curvature angles.
METHODS
Four brands of nickel-titanium (NiTi) endodontic files were selected: WaveOne Primary (Dentsply Sirona, Ballaigues, Switzerland), WaveOne Gold Primary (Dentsply Sirona), ProTaper Universal F2 (Dentsply Sirona), and ProTaper Next X2 (Dentsply Sirona). A tempered steel block containing artificial canals with 4 different canal curvatures (15°, 25°, 35°, and 45°) was constructed. Each file was used according to the manufacturer's instructions in the dynamic model, with an added 15 axial up-and-down movements of 4 mm at the end of the canal. The generated torque was recorded, and the total and maximum torque values were measured. Two-way analysis of variance and the Duncan post hoc comparison test were performed at a significance level of 95%.
RESULTS
A significant correlation between the curvature angle and the type of file system was observed (P < .05). As the degree of canal curvature increased, the generated total and maximum torque increased. At 15° and 25°, the NiTi files with reciprocating motion generated a higher total and maximum torque than files with continuous rotation. ProTaper Universal of conventional NiTi alloy showed the steepest increase in the generated total and maximum torque with the increasing curvature angle. The ProTaper Next file had the lowest torque values at the higher canal angles of 35° and 45° (P < .05).
CONCLUSIONS
Despite the study limitations, it can be concluded that root canal curvature, design, and heat treatment of NiTi files and file kinematics affect the generated torque during instrumentation.
Topics: Alloys; Dental Alloys; Dental Pulp Cavity; Equipment Design; Nickel; Root Canal Preparation; Rotation; Titanium; Torque
PubMed: 34237386
DOI: 10.1016/j.joen.2021.06.019 -
Minerva Stomatologica Dec 2020Currently in dentistry, scientific research has been conducted in the study of dental implants. Being able to optimize dental implants, in all its mechanical and...
BACKGROUND
Currently in dentistry, scientific research has been conducted in the study of dental implants. Being able to optimize dental implants, in all its mechanical and biological components, is the main objective of the research. The purpose of this article was to evaluate the structure and the molecular features of dental implant titanium alloy.
METHODS
Two different internal hexagonal connection systems belonging to FDS76 have been used as sample. Beyond the literature search, fixture and abutment surface through an X-Ray Fluorescence (XRF) method have been analyzed.
RESULTS
The surfaces have achieved an excellent level of quality and low impurity, according to commercial pure titanium alloy.
CONCLUSIONS
This information will surely bring useful information to evaluate the quality of this type of alloy and possibly improve its features.
Topics: Alloys; Dental Abutments; Dental Alloys; Dental Implant-Abutment Design; Dental Implants; Dental Materials; Fluorescence; Materials Testing; Surface Properties; Titanium; X-Rays
PubMed: 33393276
DOI: 10.23736/S0026-4970.20.04358-7 -
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 -
Dental Materials Journal Aug 2023Adhesion of the most common dental biofilm bacteria to alloys used in orthodontics in relation to surface characteristics was analyzed. Streptococcus mutans (S. mutans),...
Adhesion of the most common dental biofilm bacteria to alloys used in orthodontics in relation to surface characteristics was analyzed. Streptococcus mutans (S. mutans), Streptococcus oralis (S. oralis), Veillonella parvula (V. parvula), and Aggregatibacter actinomycetemcomitans (A. actynomicetemcomitans) were incubated for 4 h with nickel-titanium (NiTi) and stainless-steel (SS) wires. The surface roughness and free energy of the alloys, as well as the hydrophobicity of the alloys and bacteria, were assessed. NiTi had higher surface free energy and rougher (p<0.001) and more hydrophilic surfaces than SS (p<0.001). The hydrophobic properties of the bacteria decreased in the following order: V. parvula>S. oralis>S. mutans>A. actynomicetemcomitans. Bacterial adhesion generally increased over time, though this pattern was influenced by the type of alloy and the bacteria present (p<0.001). In a multiple linear regression, the principal predictor of adhesion was bacterial hydrophobicity (p<0.001), followed by time (p<0.001); alloy surface characteristics had a low influence.
Topics: Dental Alloys; Orthodontic Wires; Surface Properties; Orthodontic Appliances; Alloys; Streptococcus mutans; Titanium; Stainless Steel
PubMed: 37271541
DOI: 10.4012/dmj.2022-235 -
Natural Product Research Apr 2024A phytochemical investigation of L.C.Xu ex X.W.Zheng afforded two novel polyacetylenes, tridecane-2-monoene-4,6,8-triyntylen-1,13-diol-12---glucoside () and...
A phytochemical investigation of L.C.Xu ex X.W.Zheng afforded two novel polyacetylenes, tridecane-2-monoene-4,6,8-triyntylen-1,13-diol-12---glucoside () and tetradecane-2,8-diene-4,6-diyne-1,14-diol-13---glucoside (), together with ten known compounds (). Their chemical structures were elucidated by NMR and MS spectrums as well as the comparison of the published data. Furthermore, the chemotaxonomy of the yielded compounds was also discussed.
Topics: Plant Extracts; Polyynes; Dental Porcelain; Glucosides; Glycosides; Molecular Structure; Titanium; Metal Ceramic Alloys
PubMed: 36255124
DOI: 10.1080/14786419.2022.2134864 -
BMC Oral Health Sep 2021Nickel-titanium (NiTi) archwires are routinely used for initial leveling and alignment of teeth in orthodontic treatment. This study aimed to clinically compare the... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Nickel-titanium (NiTi) archwires are routinely used for initial leveling and alignment of teeth in orthodontic treatment. This study aimed to clinically compare the level of pain and tooth alignment in orthodontic treatment with A-NiTi versus Cu-NiTi archwires.
METHODS
In this parallel randomized clinical trial, 88 orthodontic patients (12-25 years) with an irregularity index > 2 mm in the anterior site of the lower dental arch who required non-extraction orthodontic treatment of the lower arch were randomized into two age- and sex-matched groups (n = 44) for treatment with A-NiTi and Cu-NiTi initial archwires. Each archwire was used for 6 weeks. After 6 weeks, the irregularity index was measured, and the level of pain was scored using the Modified McGill pain questionnaire (MPQ) and visual analog scale (VAS) according to the time of onset and duration of pain, and analgesic intake. Data were analyzed by paired t test, independent samples t test, and Chi-square test (P < 0.05).
RESULTS
The irregularity index significantly decreased in both groups after 6 weeks of treatment (P < 0.001). However, the difference in this respect was not significant between the two groups (P > 0.05). Pain perception (P = 0.487), duration of pain (P = 0.546), and analgesic intake (P = 0.102) were not significantly different between the two groups either.
CONCLUSION
Both A-NiTi and Cu-NiTi archwires are equally effective for tooth alignment in the anterior site of the lower dental arch and have no significant difference with regard to the level of pain experienced by patients.
TRIAL REGISTRATION NUMBER
IRCT20190705044102N1 and Name of the registry: Iranian registry of clinical trials (https://irct.ir/) Date of registration: September, 26, 2019.
Topics: Dental Alloys; Humans; Iran; Nickel; Orthodontic Wires; Pain; Titanium; Tooth Movement Techniques
PubMed: 34488744
DOI: 10.1186/s12903-021-01789-5 -
European Journal of Orthodontics Mar 2022The aim of this systematic review was to compare the different force delivery systems for orthodontic space closure by sliding mechanics. (Meta-Analysis)
Meta-Analysis
BACKGROUND/OBJECTIVES
The aim of this systematic review was to compare the different force delivery systems for orthodontic space closure by sliding mechanics.
SEARCH METHODS
Multiple sources including Cochrane Central, Ovid Medline, Embase etc. were used to identify all relevant studies.
SELECTION CRITERIA
Randomized controlled trials (RCT) of parallel-group and split-mouth designs were included.
PARTICIPANTS
Orthodontic patients of any age treated with fixed orthodontic appliances and requiring space closure.
DATA COLLECTION AND ANALYSIS
Search result screening, data extraction and quality assessment were performed independently and in duplicate by 2 reviewers. The included studies were grouped into parallel-arm and split-mouth studies and subgroup analysis was then performed for the type of retraction subsets; en-masse and individual canine retraction. A traditional meta-analysis, and network meta-analysis (NMA) for direct and indirect comparisons for the rate of space closure were performed.
RESULTS
Thirteen studies, six parallel-arm and seven split-mouth were included. The traditional meta-analysis comparing Nickel-titanium (NiTi) closed coil springs and elastomeric power chain for the rate of tooth movement showed statistically significant difference favouring NiTi springs (MD: 0.24; 95% CI, 0.03-0.45; I2 0%, P = 0.02) and the comparison between NiTi springs and active ligatures also showed statistically significant result favouring NiTi springs (MD: 0.53; 95% CI, 0.44-0.63; I2 0%, P ˂ 0.00001) for the rate of tooth movement. NMA for the rate of space closure showed fairly confident evidence for NiTi coil springs when compared with elastomeric chain and active ligatures. The NiTi coil spring ranked best between all methods of space closure.
CONCLUSIONS
There is moderate quality evidence in favour of NiTi coil springs for the rate of space closure when compared with active ligature and low quality of evidence favouring NiTi springs when compared with elastomeric chain. The ranking from NMA showed NiTi coil springs to be the best method for space closure with 99% chance. An urgent need for standardization of study designs and the need for development of an agreed core outcome sets and core outcome instrument measurement sets is evident.
REGISTRATION
PROSPERO CRD42020157811.
Topics: Dental Alloys; Elasticity; Humans; Orthodontic Space Closure; Orthodontic Wires; Titanium; Tooth Movement Techniques
PubMed: 34609513
DOI: 10.1093/ejo/cjab047 -
The Journal of Prosthetic Dentistry Nov 2023Reusing the powder in selective laser melting machines after multiple cycles is a cost-effective procedure for dental laboratories. However, information on the...
STATEMENT OF PROBLEM
Reusing the powder in selective laser melting machines after multiple cycles is a cost-effective procedure for dental laboratories. However, information on the metal-ceramic bond strength of the framework fabricated by using recycled powder is lacking.
PURPOSE
The purpose of this in vitro study was to investigate how the bonding agent and repeated alloy powder reuse affected the metal-ceramic bond strength of cobalt chromium frameworks fabricated by using selective laser melting.
MATERIAL AND METHODS
Four square and 40-bar-shaped cobalt chromium frameworks were fabricated by selective laser melting. Half were produced by using virgin alloy powder (Group V; n=2, n=20), and half with 30-times reused powder (Group R; n=2, n=20). The particle size of each powder was measured by using scanning electron microscopy, and its phase composition was characterized by using radiograph diffraction. Each group was divided into 2 subgroups (Group W [Wash Opaque] and Group N [NP-Bond]) according to the brand of bonding agent used. After ceramic application, the metal-ceramic bond strengths were evaluated by using 3-point bend tests. The bonding agents' chemical composition was analyzed by using radiograph fluorescence. Bond strength data were analyzed by using a 2-way analysis of variance (α=.05).
RESULTS
Mean ±standard deviation bond strengths did not differ significantly (P>.05) between Groups V (31.25 ±4.65) and R (30.88 ±4.78). Group W (35.34 ±1.78) had significantly higher bond strength than Group N (26.80 ±1.74; P<.001). Radiograph diffraction analysis found that the phase composition of all powders was similar. The bonding agent in Group W contained cerium, whereas, that in Group N did not.
CONCLUSIONS
Metal-ceramic bond strength was unaffected by alloy powder reuse. However, the bonding agent brand may affect the bond strength of cobalt chromium frameworks fabricated by using selective laser melting.
Topics: Dental Porcelain; Powders; Cobalt; Chromium; Metal Ceramic Alloys; Chromium Alloys; Materials Testing; Ceramics; Lasers; Dental Bonding; Surface Properties
PubMed: 37718178
DOI: 10.1016/j.prosdent.2023.08.008