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Journal of Prosthodontics : Official... Apr 2024Bioceramic coatings have been shown to promote bone repair, which aids in the early integration of implants. This study aimed to evaluate the influence of air abrasion...
PURPOSE
Bioceramic coatings have been shown to promote bone repair, which aids in the early integration of implants. This study aimed to evaluate the influence of air abrasion with a bioceramic abrasive on the surface characteristics of different implant materials and surfaces. The dissolution of the applied treatment from the surfaces over 3 weeks was also assessed.
MATERIALS AND METHODS
Discs of three alloys used for dental implants were studied and compared: two types of commercially pure titanium (CpTi)/ (CpTi SLActive) and titanium-zirconia (TiZr). The tested surfaces were: CpTi control (CpC), sandblasted (SB), sandblasted and acid-etched (SBE), and CpTi SLActive®, (TiZr) Roxolid®. Three discs from each group underwent air abrasion with apatite bioceramic powders, 95% hydroxyapatite (HA)/5% calcium oxide (CaO), and 90% hydroxyapatite (HA)/10% calcium oxide (CaO). The treated discs were surface characterized by optical profilometry to obtain surface roughness, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) to compare element weight percentages of titanium, calcium, and phosphate. Dissolution was assessed using inductively coupled plasma optic emission spectrometry (ICP-OES).
RESULTS
Bioceramic powders were deposited on all tested surfaces leading to changes in surface characteristics. The only statistically significant differences between the material groups for surface roughness were found with 95% HA/5% CaO powder in the Sp and Rp parameters (p = 0.03 and 0.04, respectively). There were no significant differences in the Ca and P wt% between all groups and powders 95% HA/5% CaO and 90% HA/10% CaO (p = 0.14, 0.18, and p = 0.15, 0.12, respectively). A non-uniform dispersion of the treatment on the surface layer was visible on all treated surfaces. The bioceramic powder continued to dissolute from the tested surfaces for 3 weeks.
CONCLUSION
Bioceramic abrasion modifies implant surface characteristics, although the change in surface characteristics resulting from such treatment was not influenced by the implant material or surface treatment. Air abrasion with hydroxyapatite and calcium oxide bioceramics leaves powder deposits on the treated implant surfaces that could potentially influence the healing of implants affected by peri-implantitis.
PubMed: 38594924
DOI: 10.1111/jopr.13857 -
Dental and Medical Problems 2024Nickel-titanium (NiTi) file separation during endodontic treatment is an undesirable event. This phenomenon needs to be understood by knowing the factors influencing... (Review)
Review
Nickel-titanium (NiTi) file separation during endodontic treatment is an undesirable event. This phenomenon needs to be understood by knowing the factors influencing fracture in endodontic files. There is a large amount of literature where these factors and their influence have been studied, increasing the knowledge about the mechanisms involved, mainly related to wire technology, file shapes and geometry, operator manipulation, the anatomy of the root canal, and the irrigation and sterilization processes. As many factors are involved, the complexity of the fracture phenomena increases and the isolated correlation of one factor with the file fracture becomes a small part of comprehending the separation phenomena. This thematic review aims to compile important reports from 2014 to 2022 on the factors influencing NiTi file separation. The information obtained was classified into wire technology, file geometry, operational aspects, irrigation and sterilization, and anatomy. For this purpose, the Scopus, Web of Science and ScienceDirect databases were consulted using a search string. Filters were applied to consolidate the final set of relevant papers covering the subject of factors influencing endodontic file separation. It was found that the fracture of NiTi files incorporates different mechanisms that operate simultaneously during the endodontic procedure and strongly affect the instrument performance. The collected information promotes good practices to prevent file separation.
Topics: Nickel; Titanium; Humans; Root Canal Preparation; Equipment Failure; Equipment Design; Sterilization; Dental Instruments
PubMed: 38686969
DOI: 10.17219/dmp/156805 -
The Saudi Dental Journal Jun 2024This in vitro study aimed to evaluate the additive manufacturing (AM) of cobalt chromium Co-Cr and titanium Ti alloy clasps for clinical use. After scanning the Ni-Cr...
This in vitro study aimed to evaluate the additive manufacturing (AM) of cobalt chromium Co-Cr and titanium Ti alloy clasps for clinical use. After scanning the Ni-Cr die of the first molar, Akers' clasps were designed using computer-aided design/ computer-aided manufacturing (CAD/CAM). The clasps were manufactured from Co-Cr-W dental alloy and Ti-6Al-4V alloy powder using AM machines. Then, they were divided into two groups. The initial retentive force of the clasps was measured using a universal testing machine. Cyclic loading of the clasps was carried out by a specially designed insertion-removal testing apparatus in wet condition up to 5000 cycles. Retentive force was measured at 1000, 2000, 3000, 4000, and 5000 cycles. Moreover, the intaglio surface of each clasp was scanned using the scanner; and superimposition between the pre- and post-cycling clasp files was performed to evaluate deformation after cyclic loading. The fitting surfaces of retentive clasp tips were examined with a scanning electron microscope (SEM). Finally, it has been found that the initial retentive force for the Co-Cr group was 10.81 ± 0.37 N, and for the Ti group was 5.41 ± 0.18 N. Additionally, during the testing periods, both Co-Cr and Ti clasps continued to lose retentive force within the cycles of placement and removal. This effect was more prominent in the Co-Cr than in the Ti clasps. The distances between pre- and post-cycling in the retentive arm were -0.290 ± 0.11 mm and -0.004 ± 0.01 mm in Co-Cr and Ti alloys, respectively, and in the reciprocal arm were -0.072 ± 0.04 mm and -0.032 ± 0.04 mm in Co-Cr and Ti alloys, respectively. The retentive force required to remove the Ti clasps was found to be significantly lower than those required to dislodge the Co-Cr clasps. Co-Cr and Ti clasps lost significant amounts of retentive force from the initial use to the 3.5-year periods of simulated clinical use.
PubMed: 38883903
DOI: 10.1016/j.sdentj.2024.04.001 -
BMC Oral Health Dec 2023Titanium is a commonly used material for dental implants owing to its excellent biocompatibility, strength-to-weight ratio, corrosion resistance, lightweight nature,...
BACKGROUND
Titanium is a commonly used material for dental implants owing to its excellent biocompatibility, strength-to-weight ratio, corrosion resistance, lightweight nature, hypoallergenic properties, and ability to promote tissue adhesion. However, alternative materials, such as titanium alloys (Ti-Al-2 V) and zirconia, are available for dental implant applications. This study discusses the application of Density Functional Theory (DFT) in evaluating dental implant materials' mechanical properties and structural stability, with a specific focus on titanium (Ti) metal. It also discusses the electronic band structures, dynamic stability, and surface properties. Furthermore, it presents the mechanical properties of Ti metal, Ti-Al-2 V alloy, and zirconia, including the stiffness matrices, average properties, and elastic moduli. This research comprehensively studies Ti metal's mechanical properties, structural stability, and surface properties for dental implants.
METHODS
We used computational techniques, such as the CASTEP code based on DFT, GGA within the PBE scheme for evaluating electronic exchange-correlation energy, and the BFGS minimization scheme for geometry optimization. The results provide insights into the structural properties of Ti, Ti-Al-2 V, and zirconia, including their crystal structures, space groups, and atomic positions. Elastic properties, Fermi surface analysis, and phonon studies were conducted to evaluate the tensile strength, yield strength, ductility, elastic modulus, Poisson's ratio, hardness, fatigue resistance, and corrosion resistance.
RESULTS
The findings were compared with those of Ti-Al-2 V and zirconia to assess the advantages and limitations of each material for dental implant applications. This study demonstrates the application of DFT in evaluating dental implant materials, focusing on titanium, and provides valuable insights into their mechanical properties, structural stability, and surface characteristics.
CONCLUSIONS
The findings of this study contribute to the understanding of dental implant material behavior and aid in the design of improved materials with long-term biocompatibility and stability in the oral environment.
Topics: Humans; Dental Implants; Titanium; Density Functional Theory; Dental Materials; Alloys; Materials Testing; Surface Properties
PubMed: 38041086
DOI: 10.1186/s12903-023-03691-8 -
International Orthodontics Dec 2023A TiNb alloy wire (GUMMETAL® [GM], Toyota Central R&D Labs, Inc., Nagakute, Japan) was recently developed with unique properties for orthodontic applications. This... (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVES
A TiNb alloy wire (GUMMETAL® [GM], Toyota Central R&D Labs, Inc., Nagakute, Japan) was recently developed with unique properties for orthodontic applications. This pilot split-mouth randomized controlled trial compared maxillary canine retraction during space closure using sliding mechanics on GM vs. stainless steel (SS) archwires.
METHODS
Subjects who met the inclusion criteria were treated with fixed appliances and maxillary first-premolar extractions between September 2020 and March 2022. After leveling and aligning, maxillary archwires, fabricated by crimping together segments of 0.016×0.022" GM and SS archwires, were placed and canine retraction initiated using nickel-titanium coil springs. Digital models of the maxillary arch were superimposed at 0, 4, 8 and 12 weeks and the amount of canine movement (mm), rate of movement (mm/month), and 3-dimensional changes (rotational, vertical extrusion, tip) were measured and compared statistically.
RESULTS
Of the 12 subjects recruited, only six completed the study with a median age of 15.8 years (12.0-17.4 years). At 12 weeks, the median canine retraction was 3.41mm (IQR: 2.10, 4.76) with GM versus 3.71mm (IQR: 1.62, 6.45) with SS. The retraction rate was 1.14mm/month (IQR: 0.69, 1.59) with GM, versus 1.24mm/month (IQR: 0.54, 2.15) with SS. The median rotational, vertical and tip changes of the canine were 7.90̊, 0.59mm and 6.15̊ with GM, and 7.25̊, 0.29mm and 2.05̊ with SS. Intergroup differences with all measurements were not statistically significant.
CONCLUSION
No significant differences were found between GM and SS during maxillary canine retraction. GM demonstrated clinical potential for space closure mechanics, however, future larger studies are needed.
Topics: Humans; Adolescent; Stainless Steel; Dental Alloys; Orthodontic Wires; Orthodontic Space Closure; Alloys; Mouth; Titanium; Tooth Movement Techniques; Cuspid
PubMed: 37774499
DOI: 10.1016/j.ortho.2023.100810 -
Journal of Oral Biosciences Sep 2023There have been no reports on the radiopaque properties of new polyetheretherketone (PEEK) crowns for locating crowns during accidental ingestion or aspiration and...
OBJECTIVES
There have been no reports on the radiopaque properties of new polyetheretherketone (PEEK) crowns for locating crowns during accidental ingestion or aspiration and detection of secondary caries, which is essential information for clinical application. This study aimed to investigate whether the radiopaque properties of PEEK crowns could be used to identify the site of accidental ingestion or aspiration and detect secondary caries.
METHODS
Four types of crowns were fabricated: three non-metal crowns (PEEK, hybrid resin, and zirconia) and one full metal cast crown (gold-silver-palladium alloy). Initially, the images for these crowns were compared using intraoral radiography, chest radiography, cone-beam computed tomography (CBCT), and multi-detector computed tomography (MDCT); computed tomography (CT) values were calculated. Subsequently, the images for the crowns placed on the secondary caries model with two artificial cavities were compared using intraoral radiography.
RESULTS
The PEEK crowns displayed the lowest radiopaque properties on radiography and very few artifacts were observed on CBCT and MDCT. On the other hand, the CT values of the PEEK crowns were a little lower than those of the hybrid resin crowns and considerably lower than the zirconia and full metal cast crowns. The cavity could be detected in the PEEK crown-placed secondary caries model through intraoral radiography.
CONCLUSIONS
This simulated study of radiopaque properties with four types of crowns suggested that a radiographic imaging system can be used to identify the site of accidental ingestion and aspiration of PEEK crowns and to detect secondary caries of the abutment tooth within a PEEK crown.
Topics: Humans; Polymers; Benzophenones; Crowns; Polyethylene Glycols; Ketones; Dental Caries; Resins, Plant
PubMed: 37230464
DOI: 10.1016/j.job.2023.05.002 -
The Journal of Prosthetic Dentistry Nov 2023Conventional analog methods have been replaced with digital methods for removable partial denture (RPD) frameworks. However, limited information is available regarding...
STATEMENT OF PROBLEM
Conventional analog methods have been replaced with digital methods for removable partial denture (RPD) frameworks. However, limited information is available regarding the build direction of RPD frameworks and its effect on properties.
PURPOSE
The purpose of this in vitro study was to evaluate the mechanical and surface properties of the cobalt chromium (Co-Cr) alloy produced at different build angles by the laser powder bed fusion additive manufacturing (AM) technology used for RPD framework fabrication.
MATERIAL AND METHODS
Plate-shaped Co-Cr specimens (n=6) were produced by the AM technology and divided into 3 groups depending on the build angle (0, 45, or 90 degrees). The elastic modulus and fracture properties were evaluated by flexural testing. Additionally, 15 disks were printed by using the same parameters of the plates (n=5) to analyze the surface hardness with microhardness testing, and surface properties were determined by surface free energy by using the contact angle and surface roughness measured by using a profilometer. Twelve Co-Cr cylindrical specimens were produced by using the same parameters (n=4), and their microstructure was examined by using an optical microscope. One-way ANOVA was used to evaluate the overall effects of the interaction between groups, and the Tukey test was applied when the interaction was statistically significant (α=.05).
RESULTS
The flexural strength showed a statistically significant difference (P<.05), with the peak value exhibited by the 0-degree group. A statistical difference was also observed between the angulation and modulus of elasticity; however, the highest value was exhibited by the 45-degree group. For the fracture topography, all groups observed a dimple-like fracture, although the 45-degree group showed wider cleavage planes of fractures than other angulations. For microhardness, the 0- and 45-degree groups exhibited a statistical difference in relation to the 90-degree group (P<.05). For surface properties, no statistically significant difference (P>.05) was found in any of the evaluated parameters. Dependence on the build angles was evidenced by the molten pool boundaries during observation of the microstructure.
CONCLUSIONS
The build angle influenced the flexural strength and microhardness of the Co-Cr alloy produced by AM; however, it does not affect surface free energy and surface roughness.
Topics: Denture, Partial, Removable; Chromium Alloys; Elasticity; Elastic Modulus; Surface Properties; Materials Testing
PubMed: 35184888
DOI: 10.1016/j.prosdent.2021.12.019 -
The Japanese Dental Science Review Dec 2023Binary titanium-zirconium alloys have been studied as promising alternatives for Ti implants. The commercial Ti-15Zr alloy (Roxolid, Straumann) has been the major... (Review)
Review
Binary titanium-zirconium alloys have been studied as promising alternatives for Ti implants. The commercial Ti-15Zr alloy (Roxolid, Straumann) has been the major subject of numerous binary Ti-Zr alloys-related studies and has gained wide recognition in laboratory studies and clinical practices. However, binary Ti-Zr alloys of other composition ratios are still being investigated by researchers. This review aims to provide information on the potential of binary Ti-Zr alloys other than Ti-15Zr as implant materials in terms of mechanical strengths, chemical or electrochemical corrosion resistance capabilities, and biological performances. In addition, in this review, the Ti-15Zr alloy is discussed only when compared with other binary Ti-Zr alloys. From the included 26 studies, it is confirmed that the mechanical, chemical, electrochemical, and biological properties of Ti-Zr alloys are related to the Ti and Zr composition ratio in the alloy, phase, manufacturing process, and surface treatment. Among the studied alloys, α-or α' phase-Ti-5 wt, 45 wt/30at, and 50 wt. %Zr exhibited relatively more promising results for further investigation. More research is necessary to evaluate the potential for future use of these materials for implants.
PubMed: 36819742
DOI: 10.1016/j.jdsr.2023.01.002 -
Journal of Biomedical Materials... Nov 2023In-stent restenosis and thrombosis remain to be long-term challenges in coronary stenting procedures. The objective of this study was to evaluate the in vitro biological...
In-stent restenosis and thrombosis remain to be long-term challenges in coronary stenting procedures. The objective of this study was to evaluate the in vitro biological responses of trimethylsilane (TMS) plasma nanocoatings modified with NH /O (2:1 molar ratio) plasma post-treatment (TMS + NH /O nanocoatings) on cobalt chromium (CoCr) alloy L605 coupons, L605 stents, and 316L stainless steel (SS) stents. Surface properties of the plasma nanocoatings with up to 2-year aging time were characterized by wettability assessment and x-ray photoelectron spectroscopy (XPS). It was found that TMS + NH /O nanocoatings had a surface composition of 41.21 ± 1.06 at% oxygen, 31.90 ± 1.08 at% silicon, and 24.12 ± 1.7 at% carbon, and very small but essential amount of 2.77 ± 0.18 at% nitrogen. Surface chemical stability of the plasma coatings was noted with persistent O/Si atomic ratio of 1.292-1.413 and N/Si atomic ratio of ~0.087 through 2 years. The in vitro biological responses of plasma nanocoatings were studied by evaluating the cell proliferation and migration of porcine coronary artery endothelial cells (PCAECs) and smooth muscle cells (PCASMCs). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay results revealed that, after 7-day incubation, TMS + NH /O nanocoatings maintained a similar level of PCAEC proliferation while showing a decrease in the viability of PCASMCs by 73 ± 19% as compared with uncoated L605 surfaces. Cell co-culture of PCAECs and PCASMCs results showed that, the cell ratio of PCAEC/PCASMC on TMS + NH /O nanocoating surfaces was 1.5-fold higher than that on uncoated L605 surfaces, indicating enhanced selectivity for promoting PCAEC growth. Migration test showed comparable PCAEC migration distance for uncoated L605 and TMS + NH /O nanocoatings. In contrast, PCASMC migration distance was reduced nearly 8.5-fold on TMS + NH /O nanocoating surfaces as compared to the uncoated L605 surfaces. Platelet adhesion test using porcine whole blood showed lower adhered platelets distribution (by 70 ± 16%), reduced clotting attachment (by 54 ± 12%), and less platelet activation on TMS + NH /O nanocoating surfaces as compared with the uncoated L605 controls. It was further found that, under shear stress conditions of simulated blood flow, TMS + NH /O nanocoating significantly inhibited platelet adhesion compared to the uncoated 316L SS stents and TMS nanocoated 316L SS stents. These results indicate that TMS + NH /O nanocoatings are very promising in preventing both restenosis and thrombosis for coronary stent applications.
Topics: Animals; Swine; Endothelial Cells; Stents; Blood Platelets; Blood Coagulation; Chromium Alloys; Thrombosis
PubMed: 37465994
DOI: 10.1002/jbm.a.37587 -
Micromachines Jul 2023Pure titanium is limited to be used in biomedical applications due to its lower mechanical strength compared to its alloy counterpart. To enhance its properties and...
Pure titanium is limited to be used in biomedical applications due to its lower mechanical strength compared to its alloy counterpart. To enhance its properties and improve medical implants feasibility, advancements in titanium processing technologies are necessary. One such technique is equal-channel angular pressing (ECAP) for its severe plastic deformation (SPD). This study aims to surface modify commercially pure titanium using micro-arc oxidation (MAO) or plasma electrolytic oxidation (PEO) technologies, and mineral solutions containing Ca and P. The composition, metallography, and shape of the changed surface were characterized using X-ray diffraction (XRD), digital optical microscopy (OM), and scanning electron microscope (SEM), respectively. A microhardness test is conducted to assess each sample's mechanical strength. The weight % of Ca and P in the coating was determined using energy dispersive spectroscopy (EDS), and the corrosion resistance was evaluated through potentiodynamic measurement. The behavior of human dental pulp cell and periodontal cell behavior was also studied through a biomedical experiment over a period of 1-, 3-, and 7-days using culture medium, and the cell death and viability can be inferred with the help of enzyme-linked immunosorbent assay (ELISA) since it can detect proteins or biomarkers secreted by cells undergoing apoptosis or necrosis. This study shows that the mechanical grain refinement method and surface modification might improve the mechanical and biomechanical properties of commercially pure (CP) titanium. According to the results of the corrosion loss measurements, 2PassMAO had the lowest corrosion rate, which is determined to be 0.495 mmpy. The electrode potentials for the 1-pass and 2-pass coated samples are 1.44 V and 1.47 V, respectively. This suggests that the coating is highly effective in reducing the corrosion rate of the metallic CP Ti sample. Changes in the grain size and the presence of a high number of grain boundaries have a significant impact on the corrosion resistance of CP Ti. For ECAPED and surface-modified titanium samples in a 3.6% NaCl electrolyte solution, electrochemical impedance spectroscopy (EIS) properties are similar to Nyquist and Bode plot fitting. In light of ISO 10993-5 guidelines for assessing in vitro cytotoxicity, this study contributes valuable insights into pulp and periodontal cell behavior, focusing specifically on material cytotoxicity, a critical factor determined by a 30% decrease in cell viability.
PubMed: 37630077
DOI: 10.3390/mi14081541