Mineralization of Titanium Surfaces: Biomimetic Implants

The surface modification by the formation of apatitic compounds, such as hydroxyapatite, improves biological fixation implants at an early stage after implantation. The structure, which is identical to mineral content of human bone, has the potential to be osteoinductive and/or osteoconductive materials. These calcium phosphates provoke the action of the cell signals that interact with the surface after implantation in order to quickly regenerate bone in contact with dental implants with mineral coating. A new generation of calcium phosphate coatings applied on the titanium surfaces of dental implants using laser, plasma-sprayed, laser-ablation, or electrochemical deposition processes produces that response. However, these modifications produce failures and bad responses in long-term behavior. Calcium phosphates films result in heterogeneous degradation due to the lack of crystallinity of the phosphates with a fast dissolution; conversely, the film presents cracks, which produce fractures in the coating. New thermochemical treatments have been developed to obtain biomimetic surfaces with calcium phosphate compounds that overcome the aforementioned problems. Among them, the chemical modification using biomineralization treatments has been extended to other materials, including composites, bioceramics, biopolymers, peptides, organic molecules, and other metallic materials, showing the potential for growing a calcium phosphate layer under biomimetic conditions.

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In Situ Characterization of Degradation Behavior of Plasma-Sprayed Coatings on Orthopedic and Dental Implants

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.49.203 ◽

2006 ◽

Vol 49 ◽

pp. 203-211 ◽

Cited By ~ 1

Author(s):

Racquel Z. LeGeros ◽

John P. LeGeros

Keyword(s):

Calcium Phosphate ◽

Dental Implants ◽

Calcium Phosphates ◽

Interfacial Strength ◽

Precipitation Method ◽

Calcium Phosphate Coating ◽

Implant Surface ◽

Ha Coating ◽

Plasma Sprayed

Plasma-sprayed ‘HA’ coatings on commercial orthopedic and dental implants were developed to combine the strength of the metal (Ti or Ti alloy) and the bioactivity of the hydroxyapatite (HA). Several studies have shown that ‘HA’-coated implants provided greater amount of bone attachment, higher bone-implant interfacial strength and accelerated skeletal attachment. However, some reports on implant failures have been attributed to coating delamination and coating early resorption of the plasma sprayed ‘HA’ coating. This paper reviews studies on characterization and degradation of plasma-sprayed ‘HA’ coatings on orthopedic and dental implants and offers alternatives to plasma-spray method of providing calcium phosphate coating. X-ray diffraction analyses showed that plasma-sprayed HA coating consists principally of HA and amorphous calcium phosphate (ACP) with minor amounts of other resorbable calcium phosphates (α- or β-tricalcium phosphates, tetracalcium phosphate), sometimes calcium oxide. The HA/ACP ratios were found to range from 20HA/80ACP to 70HA/30ACP in coated implants from different manufacturers. In vitro initial dissolution rates in acidic buffer (pH 6, 37oC) increased with decreasing HA/ACP ratios in the coating because of the preferential dissolution of the ACP phase. These results suggest that coating with very low HA/ACP ratio may result in the premature resorption of the coating before the bone can attach to the implant thus causing loosening and eventual failure of the implant. Alternatives to plasma-sprayed ‘HA’ are implant surface modifications and low temperature calcium phosphate coatings using electrochemical deposition method or precipitation method.

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PRECIPITATION CONTROL AND MECHANICAL PROPERTY OF CALCIUM PHOSPHATE–COATED AZ31B ALLOY FOR BIOMEDICAL APPLICATION

Biomedical Engineering Applications Basis and Communications ◽

10.4015/s1016237211002529 ◽

2011 ◽

Vol 23 (03) ◽

pp. 193-203 ◽

Cited By ~ 2

Author(s):

Qiang Wang ◽

Lili Tan ◽

Qiang Zhang ◽

Jianhong Qiu ◽

Ke Yang

Keyword(s):

Magnesium Alloy ◽

Calcium Phosphate ◽

Electrochemical Impedance ◽

Biomedical Application ◽

Early Stage ◽

Calcium Phosphates ◽

Chemical Deposition ◽

Biological Properties ◽

Calcium Phosphate Coating ◽

Az31b Alloy

Surface modification is believed to be an effective way to control the biodegradation rate of magnesium alloys and improve their biological properties. In the present work, a calcium phosphate (Ca-P) coating was prepared on the AZ31B magnesium alloy by a chemical deposition method to integrate the mechanical advantages of the magnesium substrate and the good bioactivity of the ceramic coating. It was shown that the coating was mainly composed of magnesium and calcium phosphates. Scanning electron microscope coupled with the energy dispersive spectrum analyses showed that rough and crystallined Ca-P coatings with different Ca/P ratios and thickness were formed on the alloy by variation of deposition time. The corrosion resistance of AZ31B alloy was significantly improved by the Ca-P coating. Electrochemical impedance spectroscopy test was used to illustrate the reaction process of Ca-P coating on the alloy. Upon the above results, Ca-P formation mechanism on the AZ31B alloy was proposed. The heterogeneous nucleation and growth of the calcium phosphate coating may be catalyzed by the anodic dissolution of the magnesium alloy substrate in the early stage of deposition, and the deposition coating is mainly composed of the magnesium phosphate. Then calcium phosphate deposition on the alloy becomes dominant with the increase of time. Tensile test in simulated body environment results showed that the time of fracture and ultimate tensile strength for the coated AZ31B Mg alloy were higher than those of the uncoated, which is beneficial in supporting fractured bone for a longer time.

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Calcium Phosphate-Chitosan Coatings Deposited on Titanium Surfaces via Pulse Galvanostatic Electrodeposition for Dental Implants

International Journal of Electrochemical Science ◽

10.20964/2020.10.73 ◽

2020 ◽

pp. 9611-9621

Author(s):

Kyung Hee Park ◽

Keyword(s):

Calcium Phosphate ◽

Dental Implants ◽

Titanium Surfaces

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Electrochemically Deposited Calcium Phosphate Coating on Titanium Alloy Substrates

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.284-286.247 ◽

2005 ◽

Vol 284-286 ◽

pp. 247-250 ◽

Cited By ~ 9

Author(s):

John P. LeGeros ◽

Shu Jie Lin ◽

Dindo Q. Mijares ◽

Fred Dimaano ◽

Racquel Z. LeGeros

Keyword(s):

Calcium Phosphate ◽

Electric Fields ◽

Calcium Phosphates ◽

Octacalcium Phosphate ◽

Calcium Phosphate Coating ◽

Pulse Time ◽

Uniform Coating ◽

Spray Method ◽

Electrochemically Deposited ◽

Plasma Sprayed

Plasma-sprayed HA coating combines the strength of the metal and the bioactivity of the HA. However, this method has several disadvantages. Alternatives to the plasma-spray method such as electrochemical deposition (ECD) and biomimetic or precipitation methods are being explored. The purpose of this study was to develop an ECD method for coating Ti alloy substrate with different calcium phosphates (octacalcium phosphate, calcium deficient apatite, carbonatesubstituted apatite, fluoride-substituted apatite). Pairs of Ti6Al4V plates that have been mechanically polished, ultrasonically cleaned, acid etched, rinsed and dried were used as anodes and cathodes. ECD was carried out using programmed pulse time electric fields. Results showed that uniform coating with only the desired calcium phosphate can be obtained using metastable calcium phosphate solutions at different pH and temperature conditions and different electrolyte concentrations. Coating thickness varied with the duration of coating deposition. Crystal size varied with other ECD conditions (e.g., pulse time, current density). This method can be used to obtain uniform coating of the desired calcium phosphate composition at low temperatures (25 to 80oC) on substrates of any type of geometry.

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Scanning Electron Microscopic Evaluation of the Effects of an Air-Abrasive System on Dental Implants: A Comparative In Vitro Study Between Machined and Plasma-Sprayed Titanium Surfaces

Journal of Periodontology ◽

10.1902/jop.1997.68.12.1215 ◽

1997 ◽

Vol 68 (12) ◽

pp. 1215-1222 ◽

Cited By ~ 21

Author(s):

Jean-Pierre Chairay ◽

Habib Boulekbache ◽

Alain Jean ◽

Alain Soyer ◽

Philippe Bouchard

Keyword(s):

Dental Implants ◽

In Vitro Study ◽

Vitro Study ◽

Electron Microscopic ◽

Microscopic Evaluation ◽

Scanning Electron Microscopic ◽

Titanium Surfaces ◽

Plasma Sprayed ◽

Scanning Electron

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The survival rates and risk factors of implants in the early stage: a retrospective study

BMC Oral Health ◽

10.1186/s12903-021-01651-8 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Yong Yang ◽

Huiting Hu ◽

Mianyan Zeng ◽

Hongxing Chu ◽

Zekun Gan ◽

...

Keyword(s):

Risk Factors ◽

Survival Rate ◽

Dental Implants ◽

Bone Quality ◽

Early Stage ◽

Survival Rates ◽

Bone Augmentation ◽

Early Survival ◽

Immediate Implantation ◽

Implant Length

Abstract Background Few large-sample studies in China have focused on the early survival of dental implants. The present study aimed to report the early survival rates of implants and determine the related influencing factors. Methods All patients receiving dental implants at our institution between 2006 and 2017 were included. The endpoint of the study was early survival rates of implants, according to gender, age, maxilla/mandible, dental position, bone augmentation, bone augmentation category, immediate implant, submerged implant category, implant diameter, implant length, implant torque, and other related factors. Initially, SPSS22.0 was used for statistical analysis. The Chi-square test was used to screen all factors, and those with p < 0.05 were further introduced into a multiple logistic regression model to illustrate the risk factors for early survival rates of implants. Results In this study, we included 1078 cases (601 males and 477 females) with 2053 implants. After implantation, 1974 implants were retained, and the early survival rate was 96.15%. Patients aged 30–60 years (OR 2.392), with Class I bone quality (OR 3.689), bone augmentation (OR 1.742), immediate implantation (OR 3.509), and implant length < 10 mm (OR 2.972), were said to possess risk factors conducive to early survival rates. Conclusions The early survival rate of implants in our cohort exceeded 96%, with risk factors including age, tooth position, bone quality, implant length, bone augmentation surgery, and immediate implantation. When the above factors coexist, implant placement should be treated carefully.

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Biphasic Calcium Phosphate Biomaterials: Stem Cell-Derived Osteoinduction or In Vivo Osteoconduction? Novel Insights in Maxillary Sinus Augmentation by Advanced Imaging

Materials ◽

10.3390/ma14092159 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2159

Author(s):

Giovanna Iezzi ◽

Antonio Scarano ◽

Luca Valbonetti ◽

Serena Mazzoni ◽

Michele Furlani ◽

...

Keyword(s):

Calcium Phosphate ◽

Maxillary Sinus ◽

Biphasic Calcium Phosphate ◽

Calcium Phosphates ◽

Three Dimensional ◽

Sinus Augmentation ◽

Native Bone ◽

Maxillary Sinus Augmentation ◽

Posterior Maxilla

Maxillary sinus augmentation is often necessary prior to implantology procedure, in particular in cases of atrophic posterior maxilla. In this context, bone substitute biomaterials made of biphasic calcium phosphates, produced by three-dimensional additive manufacturing were shown to be highly biocompatible with an efficient osteoconductivity, especially when combined with cell-based tissue engineering. Thus, in the present research, osteoinduction and osteoconduction properties of biphasic calcium-phosphate constructs made by direct rapid prototyping and engineered with ovine-derived amniotic epithelial cells or amniotic fluid cells were evaluated. More in details, this preclinical study was performed using adult sheep targeted to receive scaffold alone (CTR), oAFSMC, or oAEC engineered constructs. The grafted sinuses were explanted at 90 days and a cross-linked experimental approach based on Synchrotron Radiation microCT and histology analysis was performed on the complete set of samples. The study, performed taking into account the distance from native surrounding bone, demonstrated that no significant differences occurred in bone regeneration between oAEC-, oAFMSC-cultured, and Ctr samples and that there was a predominant action of the osteoconduction versus the stem cells osteo-induction. Indeed, it was proven that the newly formed bone amount and distribution decreased from the side of contact scaffold/native bone toward the bulk of the scaffold itself, with almost constant values of morphometric descriptors in volumes more than 1 mm from the border.

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Characterization of Thin Chromium Coatings Produced by PVD Sputtering for Optical Applications

Coatings ◽

10.3390/coatings11020215 ◽

2021 ◽

Vol 11 (2) ◽

pp. 215

Author(s):

Andreia A. Ferreira ◽

Francisco J. G. Silva ◽

Arnaldo G. Pinto ◽

Vitor F. C. Sousa

Keyword(s):

Automotive Industry ◽

Vapor Deposition ◽

Physical Vapor Deposition ◽

Early Stage ◽

Chemical Vapor ◽

Experimental Tests ◽

Scratch Test ◽

Industrial Sectors ◽

Deposition Processes ◽

Optical Applications

PVD (physical vapor deposition) and CVD (chemical vapor deposition) have gained greater significance in the last two decades with the mandatory shift from electrodeposition processes to clean deposition processes due to environmental, public safety, and health concerns. Due to the frequent use of coatings in several industrial sectors, the importance of studying the chromium coating processes through PVD–sputtering can be realized, investing in a real alternative to electroplated hexavalent chromium, usually denominated by chromium 6, regularly applied in electrodeposition processes of optical products in the automotive industry. At an early stage, experimental tests were carried out to understand which parameters are most suitable for obtaining chromium coatings with optical properties. To study the coating in a broad way, thickness and roughness analysis of the coatings obtained using SEM and AFM, adhesion analyzes with the scratch-test and transmittance by spectrophotometry were carried out. It was possible to determine that the roughness and transmittance decreased with the increase in the number of layers, the thickness of the coating increased linearly, and the adhesion and resistance to climatic tests remained positive throughout the study. Thus, this study allows for the understanding that thin multilayered Cr coatings can be applied successfully to polymeric substrates regarding optical applications in the automotive industry.

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