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Dental Press Journal of Orthodontics 2022To evaluate, in-vitro, the change in crown inclination that occurs during orthodontic leveling and alignment using different archwire-bracket-ligation combinations.
OBJECTIVE
To evaluate, in-vitro, the change in crown inclination that occurs during orthodontic leveling and alignment using different archwire-bracket-ligation combinations.
MATERIALS AND METHODS
Four archwire types were tested: (1) 0.012-in stainless steel and (2) 0.0155-in stainless steel multi-stranded, (3) 0.012-in nitinol Orthonol® and (4) 0.012-in nitinol Thermalloy®. Combinations with five types of 0.022-in slot orthodontic brackets were tested: SmartClipTM and Time3® self-ligating brackets, Mini-Taurus® and Victory SeriesTM conventional brackets, and Synergy® conventional-low friction bracket. Conventional brackets were ligated with both stainless steel and elastomeric ligatures. The simulated malocclusion comprised 2.0mm gingival and 2.0mm labial displacements of a maxillary right central incisor. Rotation around the Y-axis (representing labio-palatal inclination) was measured for the different archwire-bracket-ligation combinations.
RESULTS
The largest rotation was measured whith Orthonol® and Thermalloy® wires when combined with SmartClipTM brackets (8.07±0.24º and 8.06±0.26º, respectively) and with Synergy® brackets ligated with stainless steel ligatures (8.03±0.49º and 8.0±0.37º, respectively). The lower rotation was recorded when Thermalloy®, multi-stranded, and Orthonol® wires were ligated with elastomeric rings to Mini-Taurus® brackets (1.53±0.18º, 1.65± 0.23º and 1.70±0.28º, respectively) and to Victory SeriesTM brackets (1.68± 0.78º, 2.92± 1.40º and 1.74±0.46º, respectively).
CONCLUSIONS
All archwire-bracket-ligation combinations produced lingual crown inclination; however, lower changes were observed when the conventional brackets were ligated with elastomeric rings. The multi-stranded archwire produced less rotation with nearly every bracket-ligation combination, compared to the other archwires. The effect of the archwire-bracket-ligation combination on tooth inclination during leveling and alignment should be considered during planning treatment mechanics.
Topics: Crowns; Dental Alloys; Orthodontic Appliance Design; Orthodontic Wires; Oxygen Isotopes; Stainless Steel; Stress, Mechanical; Surface Properties; Titanium; Tooth Movement Techniques
PubMed: 35792791
DOI: 10.1590/2177-6709.27.3.e2220489.oar -
The Journal of Advanced Prosthodontics Jun 2021The aim of this study is to compare the hardness according to the conditions of metal alloys. Moreover, the correlation between the cast crown hardness before and after...
PURPOSE
The aim of this study is to compare the hardness according to the conditions of metal alloys. Moreover, the correlation between the cast crown hardness before and after wear testing and the degree of wear for each dental alloy was assessed.
MATERIALS AND METHODS
Cast crowns of three metal alloys (Co-Cr, gold, and Ni-Cr alloys) opposing smooth-surface monolithic zirconia were used. The Vickers microhardness of the ingot (which did not undergo wear testing) and the cast crown before and after wear testing were measured for each alloy. Two-way ANOVA and Scheffé tests were used to compare the measured hardness values. Moreover, the Pearson correlation coefficient was used to evaluate the relationship between the surface hardness and the wear of the cast crown (α=.05).
RESULTS
There was no significant difference in the hardness before and after wear testing for the gold alloy (>.05); however, the hardness of the worn surface of the cast crown increased compared to that of the cast crown before the wear tests of Ni-Cr and Co-Cr alloys (<.05). Furthermore, there was no correlation between the wear and hardness of the cast crown before and after wear testing for all three metal alloys (>.05).
CONCLUSION
There was a significant difference in hardness between dental alloys under the same conditions. No correlation existed between the surface hardness of the cast crown before and after wear testing and the wear of the cast crown.
PubMed: 34234922
DOI: 10.4047/jap.2021.13.3.127 -
Environmental Science & Technology Nov 2020The Minamata Convention on Mercury (ref. 1) is a global treaty to protect human and environmental health from adverse effects of the toxic element mercury and its...
The Minamata Convention on Mercury (ref. 1) is a global treaty to protect human and environmental health from adverse effects of the toxic element mercury and its compounds. During the Third Conference of Parties (COP-3) in November 2019, elimination of the use of dental amalgam in oral health care was discussed. Dental amalgam is one of the most commonly used restorative materials in oral health care due to its strength and longevity (ref. 2). However, the use of mercury in an amalgam adds to global environmental mercury pollution and can contribute to adverse health effects on humans and other organisms. The outcomes of the COP-3 meeting included a call for information on the availability at a national scale, the economic and technical feasibility of alternatives, and the associated risks or benefits. In this feature, we discuss the risks and benefits of dental amalgam, the global tracking of availability and procurement, and the implications and realities for global phase out. We suggest a better accounting of mercury use in dental amalgam is needed with sales being made only to registered practitioners via a Know Your Customer approach.
Topics: Dental Amalgam; Environmental Pollution; Humans; International Cooperation; Mercury
PubMed: 33141561
DOI: 10.1021/acs.est.0c01248 -
Journal of Endodontics Jul 2020The aim of this review article was to discuss the concept of cryotherapy, its mechanism, physiological effect, and its different applications in the field of endodontics. (Review)
Review
INTRODUCTION
The aim of this review article was to discuss the concept of cryotherapy, its mechanism, physiological effect, and its different applications in the field of endodontics.
METHODS
The selected articles were limited to those published in the English language using the following key words: cryotherapy, cryogenic treatment of nickel-titanium, cold therapy, and cryotherapy in endodontics. The screening of articles was based on an electronic search of the following databases: PubMed, Scopus, Web of Science, and Egyptian Knowledge Bank.
RESULTS
The initial search yielded 98 citations, 78 of which were included. On the basis of the collected data, 32 studies addressed the physiological effect of cryotherapy, 10 focused on illustrating a different application of cryotherapy during root canal treatment, and 36 were concerned with the effect of cryogenic treatment on endodontic instruments.
CONCLUSIONS
It can be concluded that cryotherapy is a simple and cheap supplementary method for minimizing postoperative pain in cases of symptomatic apical periodontitis and for controlling pulpal hemorrhage during vital pulp therapy. Undoubtedly, it is also an indispensable measure for controlling postsurgical swelling and pain after endodontic surgery. However, further studies are needed to clarify the effect of cryogenic treatment of the recent generations of nickel-titanium rotary instruments.
Topics: Cryotherapy; Dental Alloys; Egypt; Endodontics; Humans; Root Canal Preparation; Root Canal Therapy; Titanium
PubMed: 32386857
DOI: 10.1016/j.joen.2020.03.019 -
General Dentistry 2023Polyetheretherketone (PEEK) resin is a high-performance thermoplastic polymer that has been introduced as a possible candidate to replace metallic components in dental... (Review)
Review
Polyetheretherketone (PEEK) resin is a high-performance thermoplastic polymer that has been introduced as a possible candidate to replace metallic components in dental prostheses. The objective of this integrative review was to compare, through analysis of studies in the literature, the mechanical performance of removable partial denture frameworks and clasps manufactured with PEEK with the performance of cobalt-chromium (Co-Cr) frameworks and clasps. The guiding question was, "Does the use of PEEK as a substitute for Co-Cr alloys for the construction of removable partial denture frameworks result in better mechanical properties?" The PubMed/ MEDLINE, Embase, Web of Science, Scopus, and SciELO databases were searched for articles published through October 2021. The JBI Critical Appraisal Checklist for Quasi-Experimental Studies was used to assess the methodologic quality of the selected in vitro studies. A total of 208 articles were identified. After the exclusion of duplicates and articles that did not meet the inclusion criteria, 7 studies- -4 in vitro and 3 three-dimensional finite element analyses- -published between 2012 and 2021 were included in the integrative review. The appraisal checklist revealed that the reviewed studies had a low risk of bias and high methodologic quality. The results of the review showed that PEEK alloys have adequate mechanical properties for use in clasps and removable partial denture frameworks, but Co-Cr alloys exhibit better mechanical properties and are more suitable in most circumstances.
Topics: Humans; Denture, Partial, Removable; Dental Clasps; Chromium Alloys; Polymers; Polyethylene Glycols; Ketones
PubMed: 37358585
DOI: No ID Found -
The Journal of Prosthetic Dentistry Dec 2020The release of titanium (Ti) particles from the surface of endosseous dental implants is not well understood.
STATEMENT OF PROBLEM
The release of titanium (Ti) particles from the surface of endosseous dental implants is not well understood.
PURPOSE
The purpose of this in vitro study was to evaluate the effect of thermocycling on the surface texture and release of Ti particles from the surface of dental implants.
MATERIAL AND METHODS
Three MSI dental implants and 3 Ti alloy (TiAlV) plates were divided into 6 subgroups (n=3). Specimens in each group were subjected to 0 (control group), 100, 200, 500, 1000, and 2000 thermocycles. After each cycling process, artificial saliva was collected, and the concentrations of released Ti particles were quantified by inductively coupled plasma-mass spectrophotometry (ICP-MS). The surfaces of the dental implants and Ti plates were evaluated before and after thermocycling by scanning electron microscopy (SEM), and SEM images were analyzed by using the ImageJ software program. Data were analyzed by mixed-model ANOVA and post hoc Tukey tests (α=.05).
RESULTS
The greatest Ti release was seen after 2000 thermocycles. After increasing the number of cycles, additional Ti particles were released. SEM images of the surfaces of the dental implants and Ti plates displayed significant changes in surface texture.
CONCLUSIONS
Thermocycling continuously removed the protective TiO layer on the surface of dental implants, resulting in the release of Ti particles. The surface treatment and texture did not affect the release of Ti particles.
Topics: Alloys; Dental Alloys; Dental Implants; Materials Testing; Microscopy, Electron, Scanning; Surface Properties; Titanium
PubMed: 32037294
DOI: 10.1016/j.prosdent.2019.11.013 -
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 -
Molecules (Basel, Switzerland) Feb 2021The aim of this study was to investigate and understand bacterial adhesion to different dental material surfaces like amalgam, Chromasit, an Co-Cr alloy, an IPS InLine...
The aim of this study was to investigate and understand bacterial adhesion to different dental material surfaces like amalgam, Chromasit, an Co-Cr alloy, an IPS InLine ceramic, yttrium stabilized tetragonal polycrystalline zirconia (TPZ), a resin-based composite, an Au-Pt alloy, and a tooth. For all materials, the surface roughness was assessed by profilometry, the surface hydrophobicity was determined by tensiometry, and the zeta potential was measured by electrokinetic phenomena. The arithmetic average roughness was the lowest for the TPZ ceramic (R = 0.23 µm ± 0.02 µm), while the highest value was observed for the Au-Pt alloy (R = 0.356 µm ± 0.075 µm). The hydrophobicity was the lowest on the TPZ ceramic and the highest on the Co-Cr alloy. All measured streaming potentials were negative. The most important cause of tooth caries is the bacterium , which was chosen for this study. The bacterial adhesion to all material surfaces was determined by scanning electron microscopy. We showed that the lowest bacterial extent was on the amalgam, whereas the greatest extent was on tooth surfaces. In general, measurements showed that surface properties like roughness, hydrophobicity and charge have a significant influence on bacterial adhesion extent. Therefore, dental material development should focus on improving surface characteristics to reduce the risk of secondary caries.
Topics: Alloys; Bacterial Adhesion; Ceramics; Composite Resins; Dental Amalgam; Humans; Hydrophobic and Hydrophilic Interactions; Materials Testing; Methacrylates; Microscopy, Electron, Scanning; Particle Size; Streptococcus mutans; Surface Properties; Urethane
PubMed: 33670043
DOI: 10.3390/molecules26041152 -
Journal of Orofacial Orthopedics =... Jan 2022Gummetal® (Maruemu Works, Osaka, Japan), a new orthodontic wire material successfully used in clinical applications since 2006, is biocompatible and exhibits...
OBJECTIVES
Gummetal® (Maruemu Works, Osaka, Japan), a new orthodontic wire material successfully used in clinical applications since 2006, is biocompatible and exhibits exceptionally high elasticity, nonlinear elastic behavior, plasticity and strength. Systematic comparisons of friction behavior are lacking; thus, the friction of Gummetal® in the binding modus was compared to commonly used low friction wires.
MATERIALS AND METHODS
In vivo tests were run with Gummetal®, CoCr (cobalt-chromium Elgiloy®, Rocky Mountain Orthodontics, Denver, CO, USA), β‑Ti (β-Titanium TMA®, Ormco, Orange, CA, USA), NiTi (nickel-titanium, NiTi-SE, Dentalline, Birkenfeld, Germany), and stainless steel (SS; Ref. 251-925, 3M Unitek, Monrovia, CA, USA) [dimensions: 0.014 inch (0.35 mm), 0.016 inch (0.40 mm), 0.016 × 0.022 inch (0.40 × 0.56 mm), and 0.019 × 0.025 inch (0.48 × 0.64 mm)-β-Ti not available in the dimension 0.014 inch]. These were combined with Discovery® (Dentaurum, Ispringen, Germany), Micro Sprint® (Forestadent, Pforzheim, Germany), Clarity™ (3M Unitek), and Inspire Ice™ (Ormco) and slots in the dimension 0.022 inch (0.56 mm) and, except for the 0.019 × 0.025 inch wires, in the dimension 0.018 inch (0.46 mm). They were ligated with a 0.010 inch (0.25 mm) steel ligature (Smile Dental, Ratingen, Germany). Brackets were angulated by applying a moment of force of 10 Nmm against the wire, which was pulled through the slot at 0.2 mm/s.
RESULTS
In 660 tests using 132 bracket-wire combinations, friction loss for Gummetal® was comparable to and, in a few combinations with Micro Sprint®, significantly lower (p < 0.05) than SS and CoCr. The friction for Gummetal® was significantly lower (p < 0.05) than NiTi, and β‑Ti. In some bracket-wire combinations, lower friction was found with round wires compared to rectangular wires, except for the combination with Inspire Ice™, which was higher but not significant. Slot size did not have a significant effect on friction in most combinations.
CONCLUSION
The low friction associated with Gummetal® wires during arch-guided tooth movement will be a valuable addition to the armamentarium of orthodontists.
Topics: Dental Alloys; Dental Stress Analysis; Friction; Materials Testing; Orthodontic Appliance Design; Orthodontic Brackets; Orthodontic Wires; Titanium
PubMed: 34228140
DOI: 10.1007/s00056-021-00317-y -
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